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Bioscience Glossary
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Any change from the usual or “correct.” It may not necessarily mean harmful or undesirable; it equally can mean atypical, unusual or uncommon. When used in reference to genes, an abnormal gene can result in a specific disorder.
Termination of a pregnancy before birth.
The digestibility of a dietary supplement into the blood stream.
Acellular vaccine
A vaccine containing partial cellular material as opposed to complete cells.
Active immunity
The production of antibodies against a specific disease by the immune system. Active immunity can be acquired in two ways, either through contraction of the disease or through vaccination. Active immunity usually is permanent, meaning an individual is protected from the disease for the duration of his or her life.
A short-term, intense health effect.
A genetically determined characteristic that enhances an organism’s ability to cope with its environment.
Adequate intake
A dosage recommendation that may be used on a product label where recommended daily dietary allowance information is lacking and that is labeled as daily values.
Adult stem cell
An undifferentiated cell found in a differentiated tissue that can renew itself and, with certain limitations, differentiate to yield all the specialized cell types of the tissue from which it originated. The name is confusing because we are born with so-called adult stem cells in our tissue; therefore many scientists prefer to use the term somatic stem cell instead.
Adverse event report
A report of an incident where it is believed a substance may have caused a health problem or detrimental event.
Adverse events
Undesirable experiences occurring after immunization that may or may not be related to the vaccine.
Advisory Committee on Immunization Practices (ACIP)
A panel of 10 experts who make recommendations on the use of vaccines in the United States. The panel is advised on current issues by representatives from the Centers for Disease Control and Prevention, the Food and Drug Administration, the National Institutes of Health, the American Academy of Pediatrics, the American Academy of Family Physicians, the American Medical Association and others. The recommendations of the ACIP guide immunization practice at the federal, state and local level.
A factor, such as a microorganism, a chemical substance or a form of radiation, that causes a disease or medical condition.
Agricultural biotechnology
A range of tools, including traditional breeding techniques that alter living organisms or parts of organisms to make or modify products, improve plants or animals or develop microorganisms for specific agricultural uses. Modern biotechnology includes the tools of genetic engineering.
AIDS (acquired immune deficiency syndrome)
A medical condition in which the immune system cannot function properly and protect the body from disease. As a result, the body cannot defend itself against infections (such as pneumonia). AIDS is caused by the human immunodeficiency virus (HIV), which is spread through direct contact with the blood and body fluids of an infected individual. There is no cure for AIDS; however, research efforts are ongoing to develop a vaccine.
Alien species
A species living in an area outside its historically known natural range as a result of intentional or accidental dispersal by human activities.
One of two or more alternative forms of a gene that exists at a specific gene location on a chromosome. Different alleles produce variation in inherited characteristics such as hair color or blood type. In an individual, one form of the allele (the dominant one) may be expressed more than another form (the recessive one).
A substance, usually a protein, that can cause an allergy or allergic reaction in the body.
A reaction by the body’s immune system after exposure to a particular substance, often a protein.
Alzheimer’s disease
A progressive, degenerative disease that attacks the brain and results in impaired memory, thinking and behavior. Not all cases are inherited, but genes have been found for familial forms of Alzheimer’s disease.
Amino acid
The basic building block of a protein. There are about 20 different amino acids. Long chains of amino acids make up a protein or a polypedtide chain. Examples include phenylalanine, threonine and alanine.
1. A procedure for obtaining amniotic fluid for prenatal diagnosis. 2. The genetic analysis of a sample of amniotic fluid from the womb.
A noncontagious, potentially fatal disease caused by breathing, eating or absorbing through cuts in the skin the spore-forming bacterium Bacillus anthracis.
A substance that fights bacteria.
Proteins produced by the immune system of humans and other vertebrates in response to the presence of a specific antigen, or foreign substance.
A protein found in the blood that is produced in response to foreign substances, such as bacteria or viruses, invading the body. Antibodies protect the body from disease by binding to those organisms and destroying them.
A substance that can counteract a form of poisoning. Sometimes, the antidote for a particular toxin is manufactured by injecting the toxin into an animal in small doses and the resulting antibodies are extracted from the animals’ blood. However, some toxins have no known antidote. For example, the poison ricin, which is produced from the waste byproduct of castor oil manufacture, has no antidote, and as a result is often fatal if it enters the human body in sufficient quantities.
A substance that stimulates the production of antibodies. Examples include pollen grains, dust, bacteria or viruses and most proteins.
A substance that blocks or inhibits the actions of free radicals, molecules that speed up the aging process and contribute to illness. Free radicals are found in rancid fats and oils and environmental hazards.
Antibodies capable of neutralizing a poisonous substance, or toxin. The symptoms of certain diseases, such as botulism, tetanus and diphtheria, actually are caused by the toxins produced by the infecting bacteria.
Any medicine capable of destroying or weakening a virus. The term literally means “against virus.”
Aquatic plants
The wide variety of aquatic biomass resources such as algae, giant kelp, other seaweed and water hyacinth. Certain microalgae can produce hydrogen and oxygen while others manufacture hydrocarbons and a host of other products. Examples of microalgae include chlorella, dunaliella and euglena.
Condition in which the walls of arteries become hard and thick, sometimes interfering with blood circulation.
Artificial selection
The intentional manipulation by humans of the fitness of individuals in a population to produce a desired evolutionary response.
Residue remaining after ignition of a sample determined by a definite prescribed procedure.
A general-purpose device for molecular manufacturing, capable of guiding chemical reactions by positioning molcecules.
Association genetics
A means of establishing an association between a gene and an observable trait by comparing frequencies of alleles of the gene in groups of individuals who differ in the expression of that trait.
The smallest unit of a chemical element, about a third of a nanometer in diameter.
Atomic force microscopy (AFM)
A technique for analyzing the surface of a rigid material all the way down to the level of the atom.
A drug used as an antidote for nerve agent poisoning. Troops who are likely to be attacked with chemical weapons often carry autoinjectors with atropine that can be injected quickly into the thigh.
Attenuated vaccine
A vaccine in which a live virus is weakened through chemical or physical processes in order to produce an immune response without causing the severe effects of the disease. Attenuated vaccines currently licensed in the United States include measles, mumps, rubella, polio, yellow fever and varicella. Also known as a live vaccine.
Autosomal dominant mutation
A dominant mutation in a gene that is carried on an autosome.
Autosomal gene
Any gene that is located on an autosome.
Autosomal recessive mutation
A recessive mutation in a gene that is carried on an autosome.
Autosomal traits
Traits carried on the chromosomes other than the sex chromosomes (X and Y).
Any chromosome that is not a sex chromosome (not an X or Y chromosome).
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B cells
Small, white blood cells that help the body defend itself against infection. They are produced in bone marrow and develop into plasma cells that produce antibodies. Also known as B lymphocytes.
A large family of bacteria that have a rodlike shape. They include the bacteria that cause food to spoil as well as those responsible for some types of diseases. Helpful members of the Bacillus family are used to make antibiotics or to colonize the human intestinal tract and aid with digestion.
Bacillus thuringiensis (Bt)
A species of soil bacterium that possesses genes for a group of insecticides, the Bt toxins. Different strains of the bacterium produce different Bt toxins. Some organic farmers use this bacterium as an alternative to using chemicals to control pest insects. The genes for Bt toxins have been genetically engineered into cotton plants so the plants produce the insecticides.
Tiny, one-celled organisms present throughout the environment that require a microscope to be seen. Bacteria can exist either as independent (free-living) organisms or as parasites (dependent upon another organism for life). While not all bacteria are harmful, some cause disease. Examples of bacterial disease include diphtheria, pertussis, tetanus, Haemophilus influenza and pneumococcus (pneumonia).
Balanced diet
The overall dietary pattern of foods consumed that provide all the essential nutrients in the appropriate amounts to support life processes, such as growth in children, without promoting excess weight gain..
The outer protective layer of a tree outside the cambium comprising the inner bark and the outer bark. The inner bark is a layer of living bark that separates the outer bark from the cambium and in a living tree generally is soft and moist. The outer bark is a layer of dead bark that forms the exterior surface of the tree stem. The outer bark frequently is dry and corky.
Part of four types of simple molecules or nucleotides (adenine, cytosine, thymine and guanine) that are the subunits (building blocks) of DNA and RNA.
Base sequence
The order of nucleotide bases in a DNA molecule.
The rate and extent to which a drug or dietary supplement is absorbed into general ciruclation, therby permitting access to the site of action. Measured by the concentration in body fluids, usually blood, or by the magnitude of the pharmacological response. Expressed as a fraction of an administered dose.
Biobased product
As defined by the Farm Security and Rural Investment Act, it refers to a product determined by the Secretary of Agriculture to be a commercial or industrial product (other than food or feed) that is composed in full or significantly by biological products or renewable domestic agricultural materials (including plant, animal and marine materials) or forestry materials.
Biochemical conversion
The use of fermentation or anaerobic digestion to produce fuels and chemicals from organic sources.
Fuel derived from vegetable oils or animal fats.  It is produced when a vegetable oil or animal fat is chemically reacted with an alcohol.
The totality of genes, species and ecosystems in a region or the world.
1. Useful, renewable energy produced from organic matter. 2. The conversion of the complex carbohydrates in organic matter to energy. Organic matter may either be used directly as a fuel, processed into liquids and gases or be a residual of processing and conversion.
Fuels made from biomass resources or their processing and conversion derivatives. Biofuels include ethanol, biodiesel and methanol.
A combustible gas derived from decomposing biological waste under anaerobic conditions. Biogas normally consists of 50 to 60 percent methane.
The scientific study of the geographic distribution of organisms.
The science that uses advanced computing techniques for management and analysis of biological data. Bioinformatics particularly is important as an adjunct to genomic research, which generates a large amount of complex data involving DNA sequences and hundreds of thousands of genes.
Biological attack
The deliberate release of germs or other biological substances that can make people sick.
Biological plausibility
A causal association (or relationship between two factors) that is consistent with existing medical knowledge.
Biological resources
The components of biodiversity that are of direct, indirect or potential use to humanity.
An indicator, usually of a disease or a risk for a disease. For example, blood cholesterol is a biomarker for a risk for heart disease.
Any plant-derived organic matter. Biomass available for energy on a sustainable basis includes herbaceous and woody energy crops, agricultural food and feed crops, agricultural crop wastes and residues, wood wastes and residues, aquatic plants and other waste materials, including some municipal wastes. Biomass is a heterogeneous and chemically complex renewable resource. Biomass covers a very wide range of headings, including phytomass, dendromass, zoomass, waste (domestic waste and industrial waste), biodegradable materials, residue-sourced materials, recycled materials, food production residues, agricultural residues, animal residues, vegetable residues, biomass materials and innovative waste materials (poultry litter, coffee residues, mustard husks and spice waste).
Biomass processing residues
Byproducts from processing all forms of biomass that have significant energy potential. An example is that solid wood products and pulp from logs produces bark, shavings, sawdust and spent pulping liquors. Because these residues already are collected at the point of processing, they can be convenient and relatively inexpensive sources of biomass for energy.
A major portion of the living environment of a particular region characterized by its distinctive vegetation and maintained by local climatic conditions.
The production of pharmaceuticals such as edible vaccines and antibodies in plants or domestic animals.
The use of biomass feedstock to produce electric power or heat through direct combustion of the feedstock, through gasification and then combustion of the resultant gas or through other thermal conversion processes. Power is generated with engines, turbines, fuel cells or other equipment.
A facility that processes and converts biomass into value-added products, which can range from biomaterials to fuels such as ethanol or important feedstocks for the production of chemicals and other materials.
A territory defined by a combination of biological, social and geographic criteria, rather than by geopolitical considerations.
1. The use of plants and microorganisms to consume or otherwise help remove materials (such as toxic chemical wastes and metals) from contaminated sites (especially from soil and water). 2. A natural process in which environmental problems are treated by the use of bacteria or other microorganisms that break down a problem substance, such as oil, into less harmful molecules.
All the organisms, including animals, plants, fungi and microorganisms, found in a given area.
1. A set of biological techniques developed through basic research and now applied to research and product development. Biotechnology refers to the use of recombinant DNA, cell fusion and new bioprocessing techniques. 2. Any technological application that uses biological systems, living organisms or derivatives thereof to make or modify products or processes for specific use. 3. The industrial use of living organisms or biological techniques developed through basic research. Biotechnology products include antibiotics, beer, cheese, insulin, interferon, recombinant DNA and techniques such as waste recycling.
The use of molecular biology and/or recombinant DNA technology, or in vitro gene transfer, to develop products or to impart specific capabilities to plants or other living organisms.
Terrorism using biologic agents. Biological diseases and the agents that might be used for terrorism have been listed by the Centers for Disease Control and Prevention, and the list includes a sizable number of select agents — potential weapons whose transfer in the scientific and medical communities are regulated to keep them out of unfriendly hands.
A preimplantation embryo of about 150 cells. The blastocyst consists of a sphere made up of an outer layer of cells (the trophectoderm), a fluid-filled cavity (the blastocoel) and a cluster of cells on the interior (the inner cell mass).
Blastocyst division
When a fertilized egg divides until it forms a mass of about 32 to 150 cells.
Blastomere separation
The separation of embryonic cells, known as blastomeres, for use in producing multiple organisms that are genetically identical.
Body mass index (BMI)
An indirect measure of body fat calculated as the ratio of a person’s body weight in kilograms to the square of a person’s height in meters. BMI = weight (kg)/height (m^2) or [weight (lbs)/(height in inches)^2] x 703. In children and youth, BMI is based on growth charts for age and gender, and is referred to as BMI-for-age, which is used to assess underweight, overweight and risk for overweight.
Booster shots
Additional doses of a vaccine needed periodically to “boost” the immune system. For example, the tetanus and diphtheria (Td) vaccines are recommended for adults every 10 years.
A plant-based product.
Bottom-up nanotechnology
Building organic and inorganic structures atom by atom or molecule by molecule.
An uncommon but potentially very serious illness, it is a type of food poisoning that produces paralysis of muscles via the nerve toxin botulinum (botox), which in turn is manufactured by the bacteria Clostridium botulinum.
Bovine spongiform encephalopathy (BSE)
A disease of cattle, related to scrapie of sheep, also known as mad cow disease. It is thought to be caused by a prion, or small protein, that alters the structure of a normal brain protein, which in turn results in destruction of brain neural tissue.
Breakthrough infection
Development of a disease despite a person’s response to a vaccine.
An infectious disease caused by the bacteria Brucella that results in rising and falling (undulant) fevers, sweats, malaise, weakness, anorexia , headache, myalgia (muscle pain) and back pain.
Bt crops
Crops that are genetically engineered to carry a gene from the soil bacterium Bacillus thuringiensis (Bt). The bacterium produces proteins that are toxic to some pests but nontoxic to humans and other mammals. Crops containing the Bt gene are able to produce this toxin, thereby providing protection for the plant. Bt corn and Bt cotton are examples of commercially available Bt crops.
Bt toxins
Insecticidal proteins produced by the soil microorganism Bacillus thuringiensis.
A sphere of 60 carbon atoms, also known as a buckyball.
Buffer zone
The region near the border of a protected area.
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Caffeic acid
An acid obtained from coffee tannin, as a yellow crystalline substance.
A unit of measure for energy obtained from food and beverages.
Candidate gene
A gene whose function or location suggests it might be responsible for a disease or a trait in a population of individuals.
Organic compounds that are composed of carbon, hydrogen and oxygen and include cellulosics, starches and sugars.
Carbon black
A powdered form of elemental carbon.
A physical or chemical agent that causes cancer. It may or may not be a mutagen.
One of the most widespread groups of naturally occurring pigments. These compounds largely are responsible for the red, yellow and orange color of fruits and vegetables and also are found in many dark green vegetables.
An individual who has a recessive, disease-causing gene mutation at a particular locus on one chromosome of a pair and a normal allele at that locus on the other chromosome. It also may refer to an individual with a balanced chromosome rearrangement. Examples include a carrier for cystic fibrosis or for sickle cell anemia.
Carrier of a chromosomal rearrangement
Applies to an individual who has a rearrangement of his or her chromosomes so the normal genetic information is present (or “balanced”), but is not in the usual 46 chromosome pattern.
Carrier of a mutated gene
Every cell contains two copies of each gene. One gene copy may be mutated (altered) and the other may be “correct.” If the mutated gene is not expressed in the cells (resulting in a particular characteristic or a disorder), the mutated gene is said to be recessive to the other, correct copy of the gene. An individual who has one correct gene copy and one faulty (recessive) gene copy is said to be a carrier for the mutation leading to a specific condition. The carriers of a recessive mutation in a gene usually are not affected, but they are at risk for passing on the mutant gene to their offspring.
Carrier screening
Testing to determine if individuals are carriers of a mutated or faulty gene for a particular disorder.
Carrier rate or frequency
The proportion of individuals in a population who have a single copy of a specific recessive gene mutation.
Carrier testing (also known as carrier detection or heterozygote testing)
Testing used to identify usually asymptomatic individuals who have a gene mutation for an autosomal recessive or X-linked recessive disorder or who have a chromosome rearrangement (translocation or inversion, for example).
Carrying capacity
The maximum number of people or individuals of a particular species that a given part of the environment can maintain indefinitely.
A substance that increases the rate of a chemical reaction by reducing the activation energy. The substance is left unchanged by the reaction.
Causative gene
A gene that in a variant form is known to be the reason for developing a specific genetic disease. Monogenic genetic diseases are due to causative genes. Examples include cystic fibrosis, sickle cell anemia and Huntington’s disease.
The lowest denomination of life thought to be possible and the fundamental unit of an animal body. Most organisms consist of more than one cell, which becomes specialized into particular functions to enable the whole organism to function properly. In humans, each body organ contains different types of cells, and at the heart of a cell is the nucleus, which contains chromosomes, or long coils of DNA. DNA provides not only a blueprint from which a cell can produce proteins to perform its function, but also a design for the entire body.
Cell-based therapies
Treatments in which stem cells are induced to differentiate into the specific cell type required to repair damaged or depleted adult cell populations or tissues.
Cell culture
A method for growing cells in the laboratory.
Cell division
The mechanism by which cells multiply during the growth of tissues or organs.
The carbohydrate that is the principal constituent of wood and other biomass. It forms the structural framework of the wood cells.
Center of diversity
Geographic region with high levels of genetic or species diversity.
Characteristic diversity
The pattern of distribution and abundance of populations, species and habitats under conditions where humanity’s influence on the ecosystem is no greater than that of any other biotic factor.
A process that wraps or binds the minerals in amino acids, it uses an agent, such as the chemical compound EDTA, to remove heavy metals from the body.
Chemical vapor deposition (CVD)
A technique used to deposit coatings, where chemicals first are vaporized and then applied using an inert carrier gas, such as nitrogen.
Small fragments of wood chopped or broken by mechanical equipment. Total tree chips include wood, bark and foliage. Pulp chips or clean chips are free of bark and foliage.
The chorion develops into the placenta. Chorionic cells have the same genetic composition as cells of the fetus. Cells of the chorion are sampled during a prenatal diagnostic test called CVS (chorionic villus sampling).
Chorionic villus sampling (CVS)
Genetic testing of a tiny tissue sample from outside the sac where the fetus develops.
The physical method of separation in which the components to be separated are distributed between two phases (or media), one of which is stationary while the other moves in a definite direction.
A strand of coiled DNA that is the self-replicating genetic structure of cells. The nucleus of each animal cell (except red blood cells) contains at least one chromosome, and the number of chromosomes in each cell differs from animal to animal. Humans have 23 pairs of chromosomes, including the pair of sex chromosomes (two X chromosomes for females versus an X and a Y chromosome for males). Chromosomes are supported by proteins called chromatin.
Chronic health condition
A health-related state that lasts for a long period of time, such as cancer and asthma.
In taxonomy, a category beneath the phylum and above the order.
Clinical genetics
A specialty of medicine concerned with the diagnosis and provision for risks of developing an illness with a genetic basis in individuals and families.
Clinical trials
Controlled studies of a specific group of patients who have been screened and who meet stringent criteria to be included in the study.
1. A genetic replica of an organism created without sexual reproduction. 2. A group of genes, cells or organisms derived from a common ancestor. Each clone is genetically identical.
The process of production of a group of genes, cells or organisms that are genetically identical from a common ancestor.
A group of anaerobic bacteria that thrive in the absence of oxygen. It includes species that cause the diseases botulism, gas gangrene and tetanus.
Clostridium perfringens
A type of bacteria that is the most common agent of gas gangrene and that also can cause food poisoning and a fulminant form of bowel disease called necrotizing colitis.
Coding region
The part of a gene that directly specifies the amino acid sequence of its protein product.
Combination vaccine
Two or more vaccines administered at once in order to reduce the number of shots given. One example is the MMR (measles, mumps and rubella) vaccine.
Capable of spreading disease. Also known as infectious.
An integrated group of species inhabiting a given area. The organisms within a community influence one another’s distribution, abundance and evolution.
Community immunity
Having a large percentage of the population vaccinated in order to prevent the spread of certain infectious diseases. Even individuals not vaccinated, such as newborns and those with chronic illnesses, are offered some protection because the disease has little opportunity to spread within the community. Also known as herd immunity.
Complementary and alternative medicine (CAM)
A group of diverse medical and health care systems, practices and products that presently are not considered part of conventional medicine. Complementary medicine is used together with conventional medicine. Alternative medicine is used in place of conventional medicine.
Complementary metal-oxide semiconductor (CMOS)
The semiconductor technology used in the transistors that are manufactured into most of today’s computer microchips.
Complex disease
A common disease for which there is no simple model of inheritance or a single disease-causing gene. This category of disease often is described as multifactorial or polygenic. Examples include Type 2 diabetes, asthma and cardiovascular disease.
Combinations of metals, ceramics, polymers and biological materials that allow multifunctional behaviors.
Present at birth; not necessarily inherited.
Conjugate vaccine
The joining of two compounds (usually a protein and polysaccharide) to increase a vaccine’s effectiveness.
Relationship between two individuals with a common ancestor (cousins, for example).
Conservation of biodiversity
The management of human interactions with genes, species and ecosystems so as to provide the maximum benefit to the present generation while maintaining their potential to meet the needs and aspirations of future generations.
A medical condition or circumstance in which the use of a certain vaccine, drug or medical procedure is not allowed or is not advisable.
Fertilization of a plant with pollen from another plant. Pollen may be transferred by wind, insects, other organisms or humans.
Culture medium
The broth that covers cells in a culture dish and contains nutrients to feed the cells as well as other growth factors that may be added to direct desired changes in the cells.
Cystic fibrosis
An inherited disease in which a thick mucus clogs the lungs and blocks the ducts of the pancreas.
Cytogenetic map
A map that illustrates where genes are located on each chromosome.
The microscopic study of chromosomes and how changes in chromosome structure and number affect individuals.
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The rate of growth and the age structure of populations, and the processes that determine those properties.
Any of several metabolic diseases affecting the body’s use of blood sugars for the intake and excretion of fluids.
Diagnostic testing
Testing designed to confirm or exclude a known or suspected genetic disorder in a symptomatic individual, or prenatally, in a fetus at risk for a certain genetic condition.
Dietary reference intakes
An umbrella term for groups of values that specify recommended dosages.
Dietary supplement
Congress defined the term in the Dietary Supplement Health and Education Act of 1994 as a product taken by mouth that contains a dietary ingredient intended to supplement the diet. The dietary ingredients may include vitamins, minerals, herbs or other botanicals, amino acids or dietary substances to supplement the diet by increasing the total dietary intake. Dietary supplements can be concentrates, metabolites, constituents or extracts. They may be found in tablets, capsules, softgels, gelcaps, liquids or powders. They also can be in other forms, such as a bar; in this case, information on the label must not represent the product as a conventional food or a sole item of a meal or diet.
Dietary Supplement Health and Education Act (DSHEA)
Passed in 1994, this law amended the Federal Food, Drug, and Cosmetic Act. It created a new regulatory framework for the safety and labeling of dietary supplements, placing them in a special category under the general umbrella of foods and requiring them to be labeled as dietary supplements.
Differentiated cells
Cells that are specialized for a particular function (heart muscle or a blood cell, for example) and do not maintain the ability to generate other kinds of cells or to revert back to a less specialized type of cell (such as stem cells).
The process whereby an unspecialized early embryonic cell acquires the features of a specialized cell such as a heart, liver or muscle cell.
A specialized electronic component with two electrodes, the anode and the cathode.
A bacterial disease marked by the formation of a false membrane, especially in the throat, that can cause death.
Dip pen nanolithography
A soft lithography technique used to create nanostructures on a substrate of interest by delivering collections of molecules via capillary transport from an AFM tip to a surface.
Dirty bomb
The use of common explosives to spread radioactive materials over a targeted area. Also known as a radiation attack, a dirty bomb is not a nuclear blast, but rather an explosion with localized radioactive contamination.
Illness or sickness often characterized by typical patient problems and physical findings.
Disease-resistant individuals
Those who have no disease yet have high risk factors.
Disease surveillance
The ongoing systematic collection and analysis of data and the provision of information, which leads to action being taken to prevent and control a disease, usually one of an infectious nature.
The drop in potency of a dietary supplement while in storage as a function of time and storage conditions (light, heat, moisture and air) Stable supplements have a low rate of disintegration, allowing for a later expiration date, while others lose potency comparatively quickly.
DNA (deoxyribonucleic acid)
The genetic material of all cells and many viruses and the molecule that encodes genetic information. DNA is a double-stranded molecule held together by weak bonds between base pairs of nucleotides. The four nucleotides in DNA contain the bases adenine (A), guanine (G), cytosine (C) and thymine (T). In nature, base pairs form only between A and T and between G and C — thus the base sequence of each single strand can be deduced from that of its partner.
DNA chip
A purpose-built microchip used to identify mutations or alterations in a gene’s DNA.
DNA sequence
The relative order of base pairs in the DNA molecule, whether it is in a fragment of DNA, in a gene, in a chromosome or in the entire genome.
DNA sequencing
The process of deciphering the precise order of nucleotide bases in a DNA molecule. That sequence is the genetic code.
Every cell contains two copies of each gene. When only one of the gene copies, or alleles, is mutated and the other allele is “correct,” yet the person is affected by a disorder due to that mutation, the mutation is described as dominant. The mutated gene is said to be dominant over the other, correct copy of the gene. A disorder or characteristic caused by a dominant gene mutation only requires one of the genes to be mutated for the person to be affected.
Dominant trait
A characteristic determined by an allele that is expressed over any other alleles for a given trait.
Double helix
The structural arrangement of DNA, which resembles a twisted ladder.
Dry nanotechnology
Derives from surface science and physical chemistry and focuses on the fabrication of structures in carbon silicon and other inorganic materials. Unlike wet technology, dry techniques admit use of metals and semiconductors.
Abnormal development, or growth, of tissues or cells.
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Ebola virus
A notoriously deadly virus that causes fearsome symptoms, the most prominent being high fever and massive internal bleeding. The Ebola virus kills as many as 90 percent of the people it infects and is one of the viruses that is capable of causing hemorrhagic (bloody) fever.
A network of organisms from many different species living together in a region and their connections through the flow of energy, nutrients and matter. Those connections occur as the organisms of different species interact with one another. The ultimate source of energy in almost every ecosystem is the sun.
Efficacy rate
A measure used to describe how effective a vaccine is at preventing disease.
Electroscanning microscope (ESM)
Used for the study of surface morphology (the study of the form or shape of an organism or part thereof) and the determination of the thickness of molecular beam epitaxy (MBE)-grown films.
Elemental analysis
The determination of carbon, hydrogen, nitrogen, oxygen, sulfur, chlorine and ash in a sample.
An animal in the early stage of development before birth. In humans, the embryo stage lasts from the time of fertilization until the end of the eighth week of gestation, when it becomes known as a fetus.
Embryonic stem (ES) cell
A primitive (undifferentiated) cell from the embryo that has the potential to become a wide variety of specialized cell types.
Embryonic stem cell line
Embryonic stem cells that have been cultured under in vitro conditions, allowing proliferation without differentiation for months to years.
Inflammation of the brain. It occurs, for example, in 1 in 1,000 cases of measles and can start after onset of the measles rash and result in a high fever, convulsions and/or a coma. It usually runs a short course with full recovery within a week, though it can result in central nervous system impairment or death.
1. Restricted to a specified region or locality. 2. The continual, low-level presence of disease in a community.
Energy balance
A state where energy intake is equivalent to energy expenditure, resulting in no net weight gain or weight loss. Energy balance in children is used to indicate equality between energy intake and energy expenditure that supports normal growth without promoting excess weight gain.
Energy density
The amount of energy stored in a given food per unit of volume or mass. Fat stores 9 kilocalories/gram, alcohol stores 7 kilocalories/gram, carbohydrate and protein each store 4 kilocalories/gram, fiber stores 1.5 to 2.5 kilocalories/gram and water has no energy.
Enucleated oocyte
An egg cell from which the nucleus has been removed mechanically. The remaining intact cytoplasm of the cell is known as a cytoplast.
A protein molecule that promotes or enables a chemical reaction in the cells (a biochemical reaction) to take place. Enzymes are essential for the correct function of the body’s metabolism.
Enzyme replacement therapy
A method of treating genetic disorders caused by a deficiency of a particular enzyme. Overcoming the deficiency by providing the body with the enzyme enables the cells to function correctly and the symptoms of the disorder may be corrected.
Enzyme-linked immunosorbent assay (ELISA)
A technique using antibodies for detecting specific proteins. It is used to test for the presence of a particular genetically engineered organism.
The occurrence of disease within a specific geographical area or population that is in excess of what normally is expected.
The part of an antigen that stimulates an immune response.
A person who studies the relationship between plants and people. An ethnobotanist examines how plants have been or are used, managed and perceived in human societies — especially how plants are used for food, medicine, cosmetics, dyeing, textiles, building, tools, currency, clothing, rituals, social life and music.
The cause of.
The act of assisting a chronically ill person to die.
Any gradual change. Organic evolution is any genetic change in organisms from generation to generation.
Ex situ conservation
A conservation method that keeps components of biodiversity alive outside their original habitat or natural environment.
Contact with infectious agents (bacteria or viruses) in a manner that promotes transmission and increases the likelihood of disease.
The evolutionary termination of a species caused by the failure to reproduce and the death of all remaining members of the species.
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A characteristic or disorder that tends to run in families. It may have genetic or nongenetic etiology.
Any of a large number of natural and synthetic materials, including manure, nitrogen, phosphorus and potassium compounds, that are spread on or worked into soil to increase its capacity to support plant growth.
Ferulic acid
A compound, C10–H10–O4, related to vanillin and obtained from certain plants.
An animal in the later stage of development before birth. In humans, the fetal stage lasts from the end of the second month until birth.
Field trial
A test of a new technique or variety, including biotech-derived varieties, done outside the laboratory but with specific requirements on location, plot size, methodology and more.
Fixed carbon
The carbon remaining after heating in a prescribed manner to decompose thermally unstable components and to distill volatiles. It is part of the proximate analysis group.
A class of water-soluble plant pigments.
Forestry residues
Includes tops, limbs and other woody material not removed in forest harvesting operations in commercial hardwood and softwood stands, as well as woody material resulting from forest management operations, such as precommercial thinnings and removal of dead and dying trees.
A pure carbon molecule composed of at least 60 atoms of carbon.
Any event or process that occurs suddenly, quickly and is intense and severe to the point of lethality.
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A male or female reproductive cell. In the female, it is called an ovum or an egg; in the male, a sperm.
Genetically engineered or genetic engineering.
The fundamental physical and functional unit of heredity. A gene is a section of a DNA molecule, or an ordered sequence of nucleotides located in a particular position on a particular chromosome that encodes a specific functional product (such as a protein or an RNA molecule).
Gene bank
A facility established for the ex situ conservation of individuals (seeds), tissues or reproductive cells of plants or animals.
Gene cloning
Isolating a gene, then making multiple copies of it by inserting it into a bacterial cell or another organism.
Gene expression
The result of the activity of a gene or genes that influences the biochemistry and physiology of an organism and may change its outward appearance.
Gene families
Groups of closely related genes that make similar products, such as proteins.
Gene flow
The movement of genes from one individual or population to another genetically compatible individual or population.
Gene mapping
Determining the relative physical locations of genes on a chromosome. It is useful for plant and animal breeding.
Gene sequencing (also known as DNA sequencing)
Determining the exact sequence of nucleotide bases in a strand of DNA to better understand the behavior of a gene.
Gene splicing
The isolation of a gene from one organism followed by the introduction of that gene into another organism using techniques of biotechnology.
Gene therapy
The addition of a functional gene or groups of genes to a cell using recombinant DNA techniques to correct a hereditary disease.
Genetic counseling
A process involving an individual or family that comprises evaluation to confirm, diagnose or exclude a genetic condition, malformation syndrome or isolated birth defect; discussion of natural history and the role of heredity; identification of medical management issues; calculation and communication of genetic risks; and provision of or referral for psychosocial support.
Genetic diversity
Variation in the genetic composition of individuals within or among species.
Genetic engineering
The technique of removing, modifying or adding genes to a DNA molecule to change the information it contains. By altering this information, genetic engineering changes the type or amount of proteins an organism is capable of producing, thus enabling it to make new substances or to perform new functions. It is done to eliminate undesirable characteristics or to produce desirable new ones.
Genetic modification (GM)
1. The production of heritable improvements in plants or animals for specific uses, via either genetic engineering or other, more traditional methods. 2. Any process that alters the genetic material of living organism.
Genetic predisposition
The presence of a gene or group of genes that might predispose a person to develop a particular health problem later in life.
Genetic testing
The analysis of human DNA, RNA, and/or chromosomes to detect inheritable or acquired disease-related genotypes, mutations, phenotypes or karyotypes.
Genetically engineered food
A food substance that has foreign genes inserted into its genetic code. Genetic engineering can be done with plants, animals or microorganisms. Scientists can move desired genes from one plant into another and even from an animal to a plant, or vice versa.
Genetically engineered organism (GEO)
An organism produced through genetic engineering.
Genetically modified organism (GMO)
1. The label GMO and the term transgenic often refer to organisms that have acquired novel genes from other organisms by laboratory gene transfer methods. GMOs have had genes from other species inserted into their genome.
The study of how traits pass from parents to children and of the molecular basis of those traits.
All the genetic material in the chromosomes of a particular organism; its size generally is given as its total number of base pairs.
Genomic imprinting
Differing expression of genetic material depending on the sex of the transmitting parent.
Genomic library
A collection of biomolecules made from DNA fragments of a genome that represent the genetic information of an organism that can be propagated and then systematically screened for particular properties. The DNA may be derived from the genomic DNA of an organism or from DNA copies made from messenger RNA molecules.
The mapping and sequencing of all the genetic material in the DNA of a particular organism as well as the use of information derived from genome sequence data to further reveal what genes do, how they are controlled and how they work together.
The genetic identity of an individual, or the set of genes possessed by an individual organism. Genotype often is evident by outward characteristics. It also refers to the specific set of alleles inherited at a locus.
A disease caused by infection with the bacterium Burkholderia mallei, usually by ingestion of contaminated food or water. Symptoms include the formation of nodular lesions in the lungs and ulceration of the mucous membranes in the upper respiratory tract. The acute form results in coughing, fever and the release of infectious nasal discharge, followed by septicaemia and death within days. In the chronic form, nasal and subcutaneous nodules develop, eventually ulcerating. Death can occur within months, while survivors act as carriers.
1. A simple, six-carbon sugar. 2. A product of hydrolysis of glucan found in cellulose and starch. 3. A sweet, colorless sugar that is the most common sugar in nature and the sugar most commonly fermented to ethanol.
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Haemophilus influenzae type b (Hib)
A bacterial infection that can result in severe respiratory infections, including pneumonia, and other diseases such as meningitis.
One of the botanical groups of dicotyledonous trees that have broad leaves in contrast to the conifers or softwoods.
A group of viruses that cause hemorrhagic fever and pneumonia. It is carried by several mouse and rat species and is spread to humans when virus-containing particles from rodent urine, droppings or saliva are stirred into the air.
Healthy weight
In children and youth, a level of body fat where co-morbidities are not obeserved.
Heating value
Higher heating value is the potential combustion energy when water vapor from combustion is condensed to recover the latent heat of vaporization. Lower heating value is the potential combustion energy when water vapor from combustion is not condensed.
A plant lacking a permanent, woody stem.
Herbaceous energy crops
Perennial nonwoody crops that are harvested annually, though they can take two to three years to reach full productivity. Examples include switchgrass, reed, canary grass, miscanthus and giant reed.
Herbaceous plants
Nonwoody species of vegetation, usually of low lignin content such as grasses.
A substance that kills plants.
Herbicide-tolerant crops
Crops that have been developed to survive application(s) of particular herbicides by the incorporation of a certain gene or genes, either through genetic engineering or through traditional breeding methods. The genes allow the herbicides to be applied to the crop to provide effective weed control without damaging the crop itself.
An individual who has two different alleles at a particular locus on the same pair of chromosomes.
Holistic medicine
An approach to medical care that emphasizes the study of all aspects of a person’s health, including physical, psychological, social, economic and cultural factors.
A complementary and alternative medical system. In homeopathic medicine, there is a belief that small, highly diluted quantities of medicinal substances are given to cure symptoms, when the same substances given at higher or more concentrated doses actually would cause those symptoms.
Refers to an individual in whom the two gene copies, or alleles, contain identical information. An individual can be homozygous for the correct copies of the gene or can be homozygous for the mutated copies of the gene.
Human embryonic stem cell
A type of pluripotent stem cell derived from the inner cell mass of the blastocyst.
Human Genome Project
An extensive international research effort to determine the sequence in which human DNA is arranged. It ended in 2003 with a complete mapping of all the genes in the human body.
Concerning human nature and the welfare and dignity of humans.
Huntington’s disease
An adult-onset disease characterized by progressive mental and physical deterioration. It is caused by an inherited dominant gene mutation.
Seed or plants produced as the result of controlled cross-pollination as opposed to seed produced as the result of natural pollination. Hybrid seeds are selected to have higher quality traits (yield or pest tolerance, for example).
An organic compound that contains only carbon and hydrogen.
The conversion, by reaction with water, of a complex substance into two or more smaller units, such as the conversion of cellulose into glucose sugar units.
A condition in which the body has an exaggerated response to a substance, such as a food or drug. Also known as an allergy.
A condition in which the body has a weakened or delayed reaction to a substance.
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Identity preservation
The segregation of one crop type from another at every stage from production and processing to distribution. This process usually is performed through audits and site visits and provides independent third-party verification of the segregation.
Immune system
The complex system in the body responsible for fighting disease. Its primary function is to identify foreign substances in the body (bacteria, viruses, fungi and parasites) and develop a defense, or immune response, against them. It involves production of protein molecules called antibodies to eliminate foreign organisms that invade the body.
Protection against a disease. The two types of immunity are passive and active. Immunity is indicated by the presence of antibodies in the blood and usually can be determined through a laboratory test.
The process through which a person or animal becomes protected against a disease. The term often is used interchangeably with vaccination or inoculation.
Recording of observable immunological characteristics of an individual, which result from interaction between the genes of that individual and the environment.
The prevention of or interference with an immune response, either by disease or drugs. After receiving an organ transplant, a patient must be immunosuppressed by drugs to prevent the body from rejecting the organ. The condition can be caused by disease (such as HIV infection or cancer) or by certain drugs (such as those used in chemotherapy). Individuals whose immune systems are compromised should not receive live, attenuated vaccines.
In situ conservation
A conservation method that attempts to preserve the genetic integrity of gene resources by conserving them within the evolutionary-dynamic ecosystems of the original habitat or natural environment.
In vitro
Performed in a test tube or other laboratory apparatus. The term literally means “in glass.”
In vitro fertilization
The union of an egg and sperm in a laboratory followed by implantation of the fertilized egg into the uterus.
Inactive vaccine
A vaccine made from viruses and bacteria that have been killed through physical or chemical processes. The killed organisms cannot cause disease.
The number of new disease cases reported in a population over a certain period of time.
Incubation period
The time elapsed between exposure to a pathogenic organism and when symptoms and signs are first apparent. Depending on the disease, the person may or may not be able to give the disease to others during the incubation period.
Indicator species
A species whose status provides information on the overall condition of the ecosystem and of other species in that ecosystem.
Individualized medicine
Another term for personalized medicine and pharmacogenomics.
Capable of spreading disease. Also known as communicable.
Infectious agents
Organisms capable of spreading disease, such as bacteria or viruses.
Infectious disease
Diseases predominantly influenced by environmental exposure to a specific bacteria or virus. Genes can make us more prone to infection or determine how sick we get when infected. An example is the fact that some individuals who are HIV positive never develop AIDS because of their genetic makeup.
A highly contagious viral infection characterized by sudden onset of fever, severe aches and pains and inflammation of the mucous membrane.
Informed consent
A process by which a subject voluntarily confirms his or her willingness to participate in a particular trial after having been informed of all aspects of the trial relevant to the subject’s decision to participate. Informed consent typically is documented by means of a written, signed and dated informed consent form.
Inner cell mass
The cluster of cells inside the blastocyst. These cells give rise to the embryonic disk of the later embryo and ultimately to the fetus.
To inject with a virus to create immunity.
Insect-resistance management
A strategy for delaying the development of pesticide resistance by maintaining a portion of the pest population in a refuge that is free from contact with the insecticide. For Bt crops this allows the insects feeding on the Bt toxin to mate with insects not exposed to the toxin produced in the plants.
Insect-resistant crops
Plants with the ability to withstand, deter or repel insects and thereby prevent them from feeding on the plant. The traits (genes) determining resistance may be selected by plant breeders through cross-pollination with other varieties of this crop or through the introduction of novel genes such as Bt genes through genetic engineering.
A substance that kills insects.
Insecticide resistance
The development or selection of heritable traits (genes) in an insect population that allow individuals expressing the trait to survive in the presence of levels of an insecticide (biological or chemical control agent) that otherwise would debilitate or kill the particular species of insect. The presence of such resistant insects makes the insecticide less useful for managing pest populations.
Intellectual property rights
The legal protection for inventions, including new technologies or new organisms (such as new plant varieties). The owner of these rights can control their use and earn the rewards for their use. This encourages further innovation and creativity. Intellectual property rights protection includes various types of patents, trademarks and copyrights.
International units
A term for measurement of vitamins that are fat soluble (do not mix with water and need fat for proper absorption) Vitamins A, E, D and K usually are measured in international units.
Investigational vaccine
A vaccine that has been approved by the Food and Drug Administration for use in clinical trials on humans but that still is in the testing and evaluation phase and is not licensed for use in the general public.
An atom or group of atoms in which the number of electrons is different from the number of protons.
A class of organic compounds and biomolecules related to the flavonoids. They act as phytoestrogens, which are thought by many to be useful in treating cancer.
Sulfur-containing compounds that largely are responsible for the typical flavor of cruciferous vegetables.
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No definitions for this letter.
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A photomicrograph of an individual’s chromosomes arranged in a standard format showing the number, size and shape of each chromosome type. It is used in low-resolution physical mapping to correlate gross chromosomal abnormalities with the characteristics of specific diseases.
Keystone species
A species whose loss from an ecosystem would cause a greater-than-average change in other species’ populations or ecosystem processes.
Knock in
Replacement of a gene by a mutant version of the same gene.
Knock out
The process of purposely removing a particular gene or trait from an organism.
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Labeling of foods
The process of developing a list of ingredients contained in foods. Labels imply the list of ingredients can be verified. The Food and Drug Administration has jurisdiction over what is stated on food labels.
LCD (liquid crystal display)
Technology used for displays in flat-screen TVs and notebook and other smaller computers. LCDs allow displays to be much thinner than cathode ray tube technology and consume much less power because they work on the principle of blocking light rather than emitting it.
LED (light-emitting diode)
A semiconductor device that emits visible light when an electric current passes through it.
An ion, molecule or molecular group that binds to another chemical entity to form a larger complex.
Lithium ion battery
A rechargeable battery with twice the energy capacity of a nickel-cadmium battery and greater stability and safety.
Live vaccine
A vaccine in which a live virus is weakened through chemical or physical processes in order to produce an immune response without causing the severe effects of the disease. Live vaccines currently licensed in the United States include measles, mumps, rubella, polio, yellow fever and varicella. Also known as an attenuated vaccine.
Locus (plural, loci)
The location on a chromosome of a gene or other chromosome marker.
A type of white blood cells that helps the body defend itself against infection. They originate in the bone marrow and are the major cellular components of immunity. The two main types are T cells (T lymphocytes) and B cells (B lymphocytes).
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A complex, large molecule formed from simpler molecules.
A large cell that helps the body defend itself against disease by surrounding and destroying foreign organisms (viruses or bacteria).
Marburg virus
The virus that causes Marburg hemorrhagic fever, a disease that affects both humans and nonhuman primates. Caused by a genetically unique, animalborne RNA virus of the filovirus family, its recognition led to the creation of this virus family. The four species of Ebola virus are the only other known members of the filovirus family.
An identifiable physical location on a chromosome whose inheritance can be monitored.
Maternal serum testing
A test that assesses the risk of fetal abnormalities such as neural tube defects and Down syndrome by analyzing a number of biochemicals in the mother’s blood during pregnancy.
The study of the melding of artificial intelligence and electromechanical machines to make machines that are greater than the sum of their parts.
Medicine response profile
A test or set of tests that indicate the likely response, positive or negative, to a drug.
The special cell division that only takes place in reproductive cells and results in egg and sperm cells that contain 23 chromosomes.
Memory cell
A group of cells that help the body defend itself against disease by remembering prior exposure to specific organisms (viruses or bacteria). Therefore, they are able to respond quickly when those organisms threaten the body repeatedly. There are memory T cells and memory B cells.
The physical and chemical processes by which energy is made available for essential body functioning, growth and development.
Tiny organisms (including viruses and bacteria) that only can be seen with a microscope.
Microelectromechanical systems (MEMS)
Technology used to integrate various electromechanical functions onto integrated circuits.
A metric measurement that is 1/1,000 part of one milligram.
The introduction of DNA into the nucleus of an oocyte, embryo or other cell by injection through a very fine needle.
A metric measurement that is 1/1,000 part of one gram.
A naturally occurring inorganic substance with a definite and predictable chemical composition and physical properties.
Minimum viable population
The smallest isolated population having a good chance of surviving for a given number of years despite the foreseeable effects of demographic, environmental and genetic events and natural catastrophes.
Compartments or organelles in the cell that are the cell’s main energy source and often are called the powerhouse of the cell. The mitochondria also contain their own DNA and therefore genes. Mitochondrial genes follow maternal inheritance.
The process of cell division in all cells except reproductive cells. Mitosis results in “daughter” cells, which are identical genetically to the parent cells.
Mode of inheritance
The manner in which a particular genetic trait or disorder is passed from one generation to the next. Autosomal dominant, autosomal recessive, X-linked dominant, X-linked recessive, multifactorial and mitrochondrial inheritance are examples.
A measure of the amount of water and other components that are volatilized at 105 degrees Celsius and present in the biomass sample.
Moisture-free basis
Biomass composition and chemical analysis data typically is reported on a moisture-free or dry-weight basis. Moisture (and some volatile matter) is removed prior to analytical testing by heating the sample at 105 degrees Celsius to constant weight. By definition, samples dried in this manner are considered moisture-free.
Molecular assembler
A molecular machine that can build a molecular structure from its component building blocks.
Molecular biology
The study of the structure and function of proteins and nucleic acids in biological systems.
Molecular genetic testing (also known as DNA testing)
Testing that involves the analysis of DNA.
A group of atoms held together by chemical bonds, it is the typical unit manipulated by nanotechnology.
A disease or trait caused by variation in a single gene.
A simple sugar such as a five-carbon sugar (xylose and arabinose) or a six-carbon sugar (glucose and fructose). Sucrose, on the other hand is a disaccharide, composed of a combination of two simple sugar units, glucose and fructose.
Moore’s Law
The observation made in 1965 by Gordon Moore, co-founder of Intel, that the number of transistors per square inch on integrated circuits had doubled every 18 months since the integrated circuit was invented. Moore predicted that this trend would continue for the forseeable future.
Ability of a cell to develop into a small number of different cell types.
Municipal wastes
Residential, commercial and institutional post-consumer wastes contain a significant proportion of plant-derived organic material that constitutes a renewable energy resource. Waste paper, cardboard, construction and demolition wood waste and yard wastes are examples of biomass resources in municipal wastes.
A physical or chemical agent that causes a permanent change (mutation) in a gene. It may or may not be a carcinogen.
A gene that has undergone a change or mutation.
A permanent change in a gene, or the process by which a gene undergoes a change in the base DNA sequence. Some mutations result in the gene no longer coding for the correct protein or producing a reduced amount of the protein. If the mutation occurs in the germ line cells it then is able to be inherited. Mutations in somatic cells cannot be inherited. Mutations can occur naturally and spontaneously, but they also can be due to exposure to mutagens. The identification and incorporation of useful mutations has been essential for traditional crop breeding, among other things.
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A prefix meaning one-billionth.
Polymer/inorganic nanocomposites are composed of two or more physically distinct components with one or more average dimensions smaller than 100 nanometers.
Molecular-sized solids formed with a repeating, three-dimensional pattern of atoms or molecules with an equal distance between each part.
Nanoelectromechanical systems (NEMS)
A generic term to describe nanoscale electrical/mechanical devices.
One-billionth of a meter.
Between 0.1 and 100 nanometers.
Areas of technology where dimensions and tolerances in the range of 0.1 to 100 nanometers play a critical role.
Natural selection
The differential contribution of offspring to the next generation by various genetic types belonging to the same populations.
To undergo the process of necrosis, which is the death of tissue in the body.
New dietary ingredient
A dietary ingredient not sold in the United States in a dietary supplement before Oct. 15, 1994.
Nipah virus
A virus that infects pigs and people, in whom it can cause a sometimes-fatal form of viral encephalitis. Nipah virus caused a severe outbreak of viral encephalitis in Malaysia in 1998.
Nuclear transfer (NT)
The generation of a new animal nearly identical to another one by injection of the nucleus from a cell of the donor animal into an enucleated oocyte of the recipient.
Nuclear transfer technology (cloning)
The process that involves the removal of the nucleus of a cell followed by the transfer of a nucleus from another cell into it.
The structure within the cell that contains the chromosomes.
The subunit of DNA and RNA. It is composed of a nitrogenous base and a five-carbon sugar bonded to a phosphate group.
In biology, the part of a cell that controls growth and reproduction.
The term coined in the 1990s by Dr. Stephen DeFelice, who defined it as any substance that is a food or a part of a food and provides medical or health benefits, including the prevention and treatment of disease. Such products may range from isolated nutrients, dietary supplements and specific diets to genetically engineered designer foods, herbal products and processed foods such as cereals, soups and beverages. Since the term was coined, its meaning has been modified. The term also has been defined as a product isolated or purified from foods and generally sold in medicinal forms not usually associated with food and demonstrated to have a physiological benefit or provide protection against chronic disease.
Any substance that can be metabolized by an organism to give energy and build tissue.
Nutrient density
The amount of nutrients that a food contains per unit volume or mass.
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An excess amount of subcutaneous body fat in proportion to lean body mass. Obesity in children and youth refers to the age and gender-specific BMI that are equal to or greater than the 95th percentile of the Centers for Disease Control and Prevention BMI charts. In most children, these values are known to indicate elevated body fat and to reflect the co-morbidities associated with excessive body fatness.
Environmental factors that may promote obesity and encourage the expression of a genetic predisposition to gain weight.
A female germ cell in the process of development. It gives rise to the ovum, which can be fertilized.
Structures with special functions within cells such as the nucleus, mitochondria and lysosomes.
Organic agriculture
A concept and practice of agricultural production that focuses on production without the use of synthetic inputs and does not allow the use of transgenic organisms. The Department of Agriculture’s National Organic Program has established a set of national standards for certified organic production.
A living thing that contains DNA and is capable of cell replication by itself, from bacteria to fungi to plants to mammals.
Sudden appearance of a disease in a specific geographic area, such as a neighborhood or a community, or in a population, such as adolescents.
Mating between different populations or individuals of the same species that are not closely related. The term can be used to describe unintended pollination by an outside source of the same crop during hybrid seed production.
A mature female reproductive cell.
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An epidemic occurring over a very large area.
A sudden strong feeling of fear that prevents reasonable thought or action.
An example, model or pattern.
Parkinson’s disease
A chronic, progressive disease that occurs when nerve cells in a part of the midbrain, the substantia nigra, die or are impaired.
Passive immunity
Protection against disease through antibodies produced by another human being or animal. Passive immunity is effective, but protection generally is limited and diminishes over time (usually a few weeks or months). For example, maternal antibodies are passed to the infant prior to birth and protect the baby for the first four to six months of life.
Organisms (bacteria, viruses, parasites and fungi) that cause disease in human beings.
A diagram of the genetic relationships and medical history of a family using standard symbols and terminology.
Personalized medicine
1. Medicine using a genetic profile. 2. The prevention, detection and treatment of disease, taking into account a person’s unique genetic profile (also known as pharmacogenomics).
Pest-resistant crops
Plants with the ability to withstand, deter or repel pests and thereby prevent them from damaging the plants. Plant pests may include insects, nematodes, fungi, viruses, bacteria, weeds and others.
A chemical that kills pests.
Pesticide resistance
The development or selection of heritable traits (genes) in a pest population that allow individuals expressing the trait to survive in the presence of levels of a pesticide (biological or chemical control agent) that would otherwise debilitate or kill this pest. The presence of such resistant pests makes the pesticide less useful for managing pest populations.
Study of the biochemical and physiological processes determining the effects of drugs on organisms.
The study of variability in drug response due to hereditary factors in different populations.
The determination and analysis of the genome (DNA) and its products (RNAs) as they relate to drug response.
1. The process of farming genetically engineered plants or animals to be used as living pharmaceutical factories. The practice has used cows, sheep, pigs, goats, rabbits and mice to produce large amounts of human proteins in their milk. Plants are being used to produce vaccines and diagnostic reagents. 2. The production of pharmaceuticals from genetically altered plants or animals.
Also known under the older name of carbolic acid, a colorless crystalline solid with a typical sweet tarry odor.
1. The observable physical and/or biochemical characteristics of a person, animal or other organism that are determined by that organism’s genetic makeup and/or environment. 2. The clinical presentation of an individual with a particular genotype.
Physical activity
Body movement produced by the contraction of skeletal muscles that result in energy expenditure above the basal level. Physical activity consists of athletic, recreational, housework, transport or occupational activities that require physical skills and utilize strength, power, endurance, speed, flexibility, range of motion or agility.
Physical inactivity
Not meeting the type, duration and frequency of recommended leisure time and occupational physical activities.
Compounds that occur naturally in plants (phyto) and under certain circumstances can have actions like human estrogen.
The structure that provides the fetus with nourishment during development. It is attached to the wall of the uterus and connects to the fetus through the umbilical cord.
An infectious disease caused by the bacterium Yersinia pestis.
Plant breeding
The use of cross-pollination, selection and certain other techniques involving crossing plants to produce varieties with particular desired characteristics (traits) that can be passed on to future plant generations.
Plant-incorporated protectants (PIPs)
Pesticidal substances introduced into plants by genetic engineering that are produced and used by the plant to protect it from pests. The protein toxins of Bt often are used as PIPs in the formation of Bt crops.
Plant pests
Organisms that might directly or indirectly cause disease, spoilage or damage to plants, plant parts or processed plant materials. Common examples include certain insects, mites, nematodes, fungi, molds, viruses and bacteria.
Plant stanols and sterols
Essential components of plant cell membranes that resemble cholesterol structurally. Plant sterols are present naturally in small quantities in many fruits, vegetables, nuts, seeds, cereals, legumes, vegetable oils and other plant sources. Plant stanols occur in even smaller quantities than plant sterols in many of the same sources.
A small, circular piece of DNA found outside the chromosome in bacteria. Plasmids are the principal tools for inserting new genetic information into microorganisms or plants and are capable of replicating independently in a host cell.
The ability of stem cells from one adult tissue to generate the differentiated cell types of another tissue.
Ability of a single stem cell to develop into many different cell types of the body.
Poliomyelitis (polio)
An acute infectious viral disease characterized by fever, paralysis and atrophy of skeletal muscles.
Polymerase chain reaction (PCR)
A technique used to create a large number of copies of a target DNA sequence of interest. One use of PCR is in the detection of DNA sequences that indicate the presence of a particular genetically engineered organism.
Chemical compounds containing multiple hydroxyl groups. Sugar alcohols, a class of polyols, commonly are added to foods because of their lower caloric content.
A long-chain carbohydrate containing at least three molecules of simple anhydrosugars linked together. Examples include cellulose and starch.
Polysaccharide vaccines
Vaccines that are composed of long chains of sugar molecules that resemble the surface of certain types of bacteria. Polysaccharide vaccines are available for pneumococcal disease, meningococcal disease and Haemophilus influenzae type b.
A group of individuals with common ancestry that is much more likely to mate with one another than with individuals from another such group.
1. To enhance or increase the effect of a drug. 2. To promote or strengthen a biochemical or physiological action or effect.
Food substances that promote the growth of certain bacteria (generally beneficial) in the intestines.
Predictive testing
Testing offered to asymptomatic individuals with a family history of a genetic disorder and a potential risk of eventually developing the disorder.
A situation in which a person, because of his or her inherited genetic makeup, might have a particular susceptibility to a condition if exposed to the correct environmental triggers.
Prenatal diagnosis
Testing performed during pregnancy to determine if a fetus is affected with a particular disorder. Chorionic villus sampling, amniocentesis, periumbilical blood sampling, ultrasound and fetoscopy are examples of procedures used either to obtain a sample for testing or to evaluate fetal anatomy.
Presymptomatic testing
A form of genetic testing that looks for the presence of a mutation in a gene prior to an individual developing any symptoms of the disorder (testing for breast cancer, for example). The detection of a specific mutation does not necessarily mean the individual definitely will develop the disorder.
Proportion of the whole population affected.
With regard to obesity, primary prevention represents avoiding the occurrence of obesity in a population, secondary prevention represents early detection of obesity through screening with the purpose of limiting its occurrence and tertiary prevention involves preventing the sequelae of obesity in childhood and adulthood.
Primary forest
A forest largely undisturbed by human activities. Also known as a natural forest.
Prion-related protein (PrP)
A normal protein, expressed in the nervous system of animals, whose structure when altered (by interaction with altered copies of itself) is the cause of scrapie in sheep, bovine spongiform encephalopathy in cattle and Creutzfeldt-Jakob disease in humans.
Dietary supplements containing potentially beneficial bacteria or yeast.
A region of DNA that regulates the level of function of other genes.
Protected area
A legally established land or water area under either public or private ownership that is regulated and managed to achieve specific conservation objectives.
A large molecule composed of one or more chains of up to several hundred amino acids in a specific order held together by peptide bonds. The order is determined by the base sequence of nucleotides in the gene that codes for the protein. Proteins are required for the structure, function and regulation of the body’s cells, tissues and organs, and each protein has unique functions. Examples include hormones, enzymes and antibodies.
Public health
The approach to medicine that is concerned with the health of the community as a whole.
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Q fever
An acute febrile illness caused by Coxiella burnetii, a species of bacteria. Q fever is a zoonotic disease, which means it is contracted from animals. Besides the sudden onset of fever, it causes headaches, malaise and pneumonia, but not a rash.
Quantum dot
A nanoscale crystalline structure that can transform the color of light.
The isolation of a person or animal who has a disease or is suspected of having a disease in order to prevent further spread of the disease.
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Every cell contains two copies of each gene. Each gene contains the information for a particular gene product, such as a protein. If a gene is mutated, the gene no longer codes for the gene product. When an individual has one gene copy, or allele, mutated and the other copy “correct,” the cell only will be producing half the amount of gene product. If that does not result in any disorder for the individual, the mutation is described as being hidden or “recessive” to the correct copy of the gene. An individual with this genetic constitution is said to be a carrier of a recessive gene mutation. For a recessive gene mutation to result in a particular characteristic or a disorder, both copies of the genes must be mutated.
Recessive trait
A characteristic determined by an allele that requires the presence of two identical alleles to be expressed.
1. Of or resulting from new combinations of genetic material or cells. 2. The genetic material produced when segments of DNA from different sources are joined to produce recombinant DNA.
Recombinant DNA molecules (rDNA)
A combination of DNA molecules of different origin that are joined using recombinant DNA technologies.
Recombinant DNA technology
Procedure used to join together DNA segments in a cell-free system (an environment outside a cell or organism). Under appropriate conditions, a recombinant DNA molecule can enter a cell and replicate there, either autonomously or after it has become integrated into a cellular chromosome.
The process by which progeny derive a combination of genes different from that of either parent.
Regenerative or reparative medicine
A treatment in which stem cells are induced to differentiate into the specific cell type required to repair damaged or depleted adult cell populations or tissues.
Recommended daily dietary allowance
Started in the 1940s to safeguard the public’s health, recommended daily dietary allowances are estimates of the nutritional needs of adults and children. These statistics were developed by the Food and Drug Administration to be used as the legal standards for labeling foods with regard to nutritional content.
The recovery of specific ecosystem services in a degraded ecosystem or habitat.
An immune reaction a patient may have against an organ or tissue that has been transplanted.
Relative risk
A measure of how much a particular risk factor (cigarette smoking) influences the risk of a specified outcome (death by age 70).
Residues of biomass
Byproducts from processing all forms of biomass that have significant energy potential. For example, making solid wood products and pulp from logs produces bark, shavings, sawdust and spent pulping liquors. Because these residues already are collected at the point of processing, they can be convenient and relatively inexpensive sources of biomass for energy.
The return of an ecosystem or habitat to its original community structure, natural complement of species and natural functions.
A potent protein toxin made from the leftover waste after processing castor beans to make castor oil.
Risk assessment
Calculation of an individual’s risk of having inherited a certain gene mutation, developing a particular disorder or having a child with a certain disorder, based on an analysis of multiple factors, including family medical history and ethnic background.
RNA (ribonucleic acid)
A molecule similar to DNA whose functions include decoding the instructions for protein synthesis that are carried by the genes. It contains the sugar ribose instead of deoxyribose, transmits genetic information from DNA to the cytoplasm and controls certain chemical processes in the cell, such as the synthesis of proteins. Double-stranded RNA forms the genetic material in some viruses. Three types of RNA exist: messenger RNA (mRNA), transfer RNA (tRNA) and ribosomal RNA (rRNA).
One of a group of viruses that cause diarrhea in children.
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A simple sugar or a more complex compound that can be hydrolyzed to simple sugar units.
Any of various plant glucosides that form soapy lathers when mixed and agitated with water. They are used in detergents, foaming agents and emulsifiers.
Scanning electron microscopy (SEM)
Involves the manipulation of an electron beam that is scanned across the surface of specially prepared specimens to obtain a greatly enlarged, high-resolution image of the specimen’s exposed structure.
Scanning force microscope (SFM)
A microscope that works by detecting the vertical position of a probe while horizontally scanning the probe or the sample relative to the other.
Scanning tunneling microscope (STM)
A device that obtains images of the atoms on the surfaces of materials. It is important for understanding the topographical and electrical properties of materials and the behavior of microelectronic devices.
Testing designed to identify individuals in a given population who are at higher risk of having or developing a particular disorder, or having a gene mutation for a particular disorder.
A way of living or a lifestyle that requires minimal physical activity and that encourages inactivity through limited choices, disincentives and structural and/or financial barriers.
A facility designed for the ex situ conservation of individual plan varieties through seed preservation and storage.
Selectable marker
A gene, often encoding resistance to an antibiotic or an herbicide, introduced into a group of cells to allow identification of those cells that contain the gene of interest from the cells that do not. Selectable markers are used in genetic engineering to facilitate identification of cells that have incorporated another desirable trait that is not easy to identify in individual cells.
Selective breeding
Making deliberate crosses or mating of organisms so the offspring will have a desired characteristic derived from one of the parents.
Septicemic plague
A form of plague that occurs when the bacteria multiply in the blood. It usually is contracted through a flea or rodent bite, and its symptoms include fever, chills, weakness, abdominal pain, shock and bleeding underneath the skin or other organs.
Pathological conditions resulting from a prior disease, injury or attack.
Determination of the order of nucleotides (base sequences) in a DNA or RNA molecule or of the order of amino acids in a protein.
Measurement of antibodies and other immunological properties in the blood serum.
Sex chromosomes
The X or Y chromosome in human beings that determines the sex of an individual. Females have two X chromosomes; males have an X and a Y chromosome.
Shelf life
The period of time during which a dietary supplement remains sufficiently potent to be effective. The expiration date on a product label should indicate the end of this time period.
Sickle cell anemia
An inherited, potentially lethal disease in which a defect in hemoglobin, the oxygen-carrying pigment in the blood, causes distortion (sickling) and loss of red blood cells, producing damage to organs throughout the body.
Side effect
An undesirable reaction resulting from immunization.
Single-gene disorder
A hereditary disorder caused by a mutant allele of a single gene. An example is Huntington’s disease.
Smart materials
Reactive materials that combine sensors and actuators and possibly computers to enable a response to environmental conditions and changes to those conditions.
Also known as variola, smallpox is a highly contagious and frequently fatal viral disease characterized by a biphasic, or two-phased, fever and a distinctive skin rash that leaves pock marks. Because of its high case-fatality rates and transmissibility, smallpox now represents a serious bioterrorist threat. It is caused by the variola virus, the incubation period is about 12 days following exposure and initial symptoms include high fever, fatigue and head and back aches. A characteristic rash, most prominent on the face, arms and legs, follows in two to three days. The rash starts with flat, red lesions that evolve at the same rate. Lesions become pus-filled and begin to crust early in the second week. Scabs develop and then separate and fall off after about three to four weeks.
SNP (single-nucleotide polymorphism)
A SNP (pronounced “snip”) is a single-base variation that occurs about every 1,000 bases along the three billion base pairs of the human genome.
SNP map
A collection of single-nucleotide polymorphisms that can be superimposed over the existing genome map, creating greater detail and facilitating further genetic studies and analysis.
Generally, one of the botanical groups of trees that in most cases have needle- or scale-like leaves. This term also refers to the conifers and the wood produced by such trees. The term has no reference to the actual hardness of the wood. The botanical name for softwoods is gymnosperms.
Somatic cell
1. A cell that contains two complete sets of chromosomes. 2. A cell of the body other than those of the gamete-forming germ line
Somatic cell nuclear transfer (SCNT)
The transfer of a cell nucleus from a somatic cell into an enucleated egg (an egg from which the nucleus has been removed). In SCNT, a nucleus from a patient’s body cell, such as a skin cell, is introduced into an unfertilized egg from which the original genetic material has been removed. The egg then is used to produce a blastocyst whose stem cells could be used to create tissue that would be compatible with that of the patient. This is the procedure used for therapeutic cloning.
Somatic gene therapy
Correcting or transplanting genes that reside in somatic cells, not in the reproductive cells.
Somatic mutation
A change or mistake in a gene that is found in the cells of the body but not in the germ or sex cells. Somatic mutations therefore cannot be passed on to future generations.
A group of organisms capable of interbreeding freely with each other but not with members of other species.
Species diversity
A function of the distribution and abundance of species.
A function of several characteristics of community or ecosystem dynamics, including the degree of population fluctuations, the community’s resistance to disturbances, the speed of recovery from disturbances and the persistence of the community’s composition through time.
A person or group that has a direct interest in a negotiation or other decision-making process.
A group of bacteria that cause a multitude of diseases. Under a microscope, Staphylococcus bacteria are round and bunched together. They can cause illness directly by infection or indirectly through products they make, such as the toxins responsible for food poisoning and toxic shock syndrome. Staphylococcus are the main culprit in hospital-acquired infections and cause thousands of deaths every year.
Stem cells
Cells with the ability to divide for indefinite periods in culture and give rise to specialized cells. Scientists work primarily with two kinds of stem cells from animals and humans: embryonic stem cells and adult stem cells, which have different functions and characteristics.
The more or less predictable changes in the composition of communities following a natural or human disturbance.
One that acts in another’s place. In Dolly the sheep’s case (the first mammal cloned from an adult cell), the surrogate was another Scottish Blackface ewe.
Refers to several types of chemical compounds containing sulfur.
Susceptibility gene
A gene that confers a risk to develop a disease but is not necessary or sufficient by itself to cause the disease.
Unprotected against disease.
Sustainable development
Development that meets the needs and aspirations of the current generation without compromising the ability to meet those of future generations.
A group of characteristics or symptoms that occur together in a recognizable pattern.
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T cell
A type of white blood cell that matures in the thymus (a small glandular organ situated behind the top of the breastbone) and is essential for various aspects of immunity, especially in combating viral infections and cancers. The major subtypes of T cells in humans include helper T cells, cytotoxic T cells and suppressor T cells. Also known as a T lymphocyte.
Tay-Sachs disease
An inherited disease of infancy characterized by profound mental retardation and early death. It is caused by a recessive gene mutation.
Therapeutic cloning
Somatic cell nuclear transfer for the isolation of embryonic stem cells.
A mercury-containing preservative that has been used in some vaccines and other products since the 1930s. There is no evidence that the low concentrations of thimerosal in vaccines have caused any harm other than minor reactions like redness or swelling at the injection site. However, in July 1999 the U.S. Public Health Service, the American Academy of Pediatrics and vaccine manufacturers agreed thimerosal should be reduced or eliminated from vaccines as a precautionary measure. Today, all routinely recommended childhood vaccines manufactured for the U.S. market contain either no thimerosal or only trace amounts.
Compounds containing the functional group composed of a sulfur atom and a hydrogen atom.
Time release
When a vitamin or mineral has a time-release factor, it means the ingredients have been coated and calibrated scientifically in tiny “memory granules” that are released over a period of two to six hours. The advantage of time release is it gives the body the vitamin or mineral gradually instead of all at once.
A part of an organism consisting of a collection of cells having a similar structure and function (a piece of skin or bone, for example).
Tissue culture
1. A process of growing a plant in the laboratory from cells rather than from seeds. The technique is used in traditional plant breeding as well as when using techniques of agricultural biotechnology. 2. The growth of animal or plant cells in vitro in an artificial culture medium for experimental research. Also known as cell culture.
Top-down nanotechnology
Making nanoscale structures by machining and etching techniques.
Ability of a single cell to develop into all the different types of cells in the body (its potential is total).
Toxic shock syndrome
A serious but uncommon bacterial infection whose symptoms include sudden high fever, a faint feeling, watery diarrhea, headache and muscle aches.
A poisonous substance produced by living cells or organisms. Toxins almost always are proteins that are capable of causing disease on contact or absorption with body tissues by interacting with biological macromolecules such as enzymes or cellular receptors. Toxins vary greatly in their severity, ranging from usually minor and acute (as in a bee sting) to almost immediately deadly (as in botulinum toxin).
Traditional breeding
Modification of plants and animals through selective breeding. Practices used in traditional plant breeding can include aspects of biotechnology such as tissue culture and mutation breeding.
The process of converting genetic instructions coded in a segment of DNA into messenger RNA.
A reversible reaction in which one ester is converted into another (as by interchange of ester groups with an alcohol in the presence of a base).
A gene from one organism inserted into another organism by recombinant DNA techniques.
1. Containing genes altered by insertion of DNA from an unrelated organism. 2. Taking genes from one species and inserting them into another species to get that trait expressed in the offspring.
Transgenic mouse
A mouse that has been genetically altered by injecting human or other foreign DNA from another animal into fertilized mouse eggs. This DNA becomes incorporated into the mouse DNA and the mouse will translate the information contained in the foreign gene. This has become a useful model for the study of various human disorders.
Transgenic organism
An organism resulting from the insertion of genetic material from another organism using recombinant DNA techniques.
The conversion of genetic information coded in a segment of mRNA into a sequence of amino acids.
The presence of a single extra chromosome, yielding a total of three chromosomes of that particular type instead of a pair. Partial trisomy refers to the presence of an extra copy of a segment of a chromosome.
A highly contagious infection caused by the bacterium Mycobacterium tuberculosis. Tubercles (tiny lumps) are a characteristic finding in TB. Most patients with tuberculosis do not need to be quarantined, though it is necessary sometimes.
A bacterial disease caused by infection with the bacterium Francisella tularensis that usually occurs in wild and domestic animals, most often rabbits. Tularemia can be transmitted to humans by contact with animal tissues or ticks and fleas and also is known as rabbit fever and deerfly fever.
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A cell that has not changed to become a specialized cell type.
Undulant fever
An infectious disease caused by the bacteria Brucella that characteristically causes rising and falling fevers, sweats, malaise, weakness, anorexia , headache, myalgia (muscle pain) and back pain.
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Injection of a killed or weakened infectious organism in order to prevent the disease.
A product that produces immunity, therefore protecting the body from the disease. Vaccines are administered through needle injections, by mouth and by aerosol.
Vaccine Adverse Event Reporting System (VAERS)
A database managed by the Centers for Disease Control and Prevention and the Food and Drug Administration. VAERS provides a mechanism for the collection and analysis of adverse events associated with vaccines currently licensed in the United States. Reports to VAERS can be made by the vaccine manufacturer, the recipient, the recipient’s parent or guardian and the recipient’s health care provider.
Vaccine Safety Datalink Project (VSD)
In order to increase knowledge about vaccine adverse events, the Centers for Disease Control and Prevention has formed partnerships with eight large health management organizations (HMOs) to continually evaluate vaccine safety. The project contains data on more than six million people. Medical records are monitored for potential adverse events following immunization. The VSD project allows for planned vaccine safety studies as well as for timely investigations of hypotheses.
Alleles that are rare; they are found in fewer than 1 percent of a population. Some mutations are variants.
A subdivision of a species for taxonomic classification. A variety is a group of individual plants that is uniform, stable and distinct genetically from other groups of individuals in the same species.
Vascular system
The organ system that moves substances to and from cells in the body. It also can help stabilize body temperature and pH levels.
1. A type of DNA element, such as a plasmid or the genome of a bacteriophage or virus, that is self-replicating and that can be used to transfer DNA segments into target cells. 2. An insect or other organism that provides a means of dispersal for a disease or parasite.
The relative capacity of a pathogen to overcome body defenses.
An infectious agent composed of a single type of nucleic acid, DNA or RNA that is enclosed in a coat of protein. It does not have a cellular structure and therefore cannot replicate outside of a living, host cell. A virus invades living cells and uses their chemical machinery to keep itself alive and to replicate itself. It can reproduce with fidelity or with errors (mutations). The ability to mutate is responsible for the ability of some viruses to change slightly in each infected person, which makes treatment more difficult. Viruses are smaller than bacteria and are not affected by antibiotics, the drugs used to kill bacteria. Viruses cause disease such as chicken pox, measles, mumps, rubella, pertussis and hepatitis.
An organic substance essential in small quantities to normal metabolism.
Volatile matter
Products, exclusive of moisture, given off by a material such as a gas or vapor, determined by definite, prescribed methods that might vary according to the nature of the material.
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Waning immunity
The loss of protective antibodies over time.
A view of health that takes into account a child’s physical, social and emotional health.
Wet nanotechnology
The study of biological systems that exist primarily in a water environment.
Whole tree chips
Wood chips produced by chipping whole trees, usually in the forest. The chips thus contain both bark and wood. They frequently are produced from low-quality trees or from tops, limbs and other logging residues.
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X chromosome
A sex chromosome. Normal females carry two X chromosomes; normal males, one.
X-linked gene
Any gene that is located on the X chromosome.
X-linked recessive mutation
A recessive mutation in a gene carried on the X chromosome.
X-linked dominant mutation
A dominant mutation in a gene carried on the X chromosome.
X-linked trait
A trait that is passed on from mother to child or from father to daughter on the X chromosome.
The transplanted tissue in a xenotransplantation.
1. Transplantation of cells, tissues or organs from one species to another. 2. The term used to describe the transfer of living cells, tissues and organs from nonhuman animals into humans for medical purposes.
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Y chromosome
A sex chromosome. Normal males carry one Y and one X chromosome, while females carry none.
Yellow fever
An acute, systemic (bodywide) illness caused by a flavivirus virus. In severe cases, the viral infection causes a high fever, bleeding into the skin and death of cells in the kidney and liver. The damage done to the liver from the virus results in severe jaundice, which yellows the skin.
A group of bacteria that appear rodlike under a microscope and include Yersinia pestis (the cause of the bubonic and pneumonic plague). Infection with Yersinia bacteria can be treated with antibiotics.
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The single cell with 46 chromosomes resulting from the fertilization of an egg (23) by a sperm (23). Through cell division (mitosis), the zygote develops into a multicellular embryo and then into a fetus.