DICTIONARY OF
BIOTECHOLOGY [THE ALPHABET “A”]
A-DNA
A particular right-handed helical form of DNA (possessing 11 base
pairs per turn), in which DNA molecules exist when they are partially
dehydrated. A-form DNA is found in fibers at 75% relative humidity and requires
the presence of sodium, potassium, or cesium as the counter ion. Instead of
lying flat, the bases are tilted with regard to the helical axis and there are
more base pairs per turn. The A-form is biologically interesting because it is
probably very close to the conformation adopted by DNA-RNA hybrids or by
RNA-RNA double-stranded regions. The reason is that the presence of the 2’2 hydroxyl group
prevents RNA from lying in the B-form. See also B-DNA, DNA-RNA HYBRID, DEOXYRIBONUCLEIC
ACID (DNA), BASE PAIR (bp).
ABC Transporters
A class of membrane transporter proteins which “transfer” across
cell membranes: sugar molecules (i.e., used by cells as “fuel”); inorganic ions
(needed to catalyze certain cellular processes); polypeptides (i.e., protein
molecules); certain anticancer drugs (thereby making it harder to halt certain
cancer tumors via use of pharmaceuticals); certain antibiotics (thereby
conferring antibiotic resistance to some pathogenic bacteria). ABC transporter
molecules are embedded in the plasma membrane (i.e., surface “skin”) of cells.
See also CELL, PLASMA MEMBRANE, PROTEIN, CATALYST, ION, POLYPEPTIDE (protein),
CANCER, CHEMOTHERAPY, ANTIBIOTIC RESISTANCE.
AβPP
See
AMYLOID β PROTEIN PRECURSOR (AβPP).
Aw
WATER ACTIVITY (AW). [defined below]
aAI-1
ALPHA AMYLASE INHIBITOR-1. [defined below]
ABC
ASSOCIATION OF BIOTECHNOLOGY COMPANIES ABC). [defined below]
Abiogenesis
Spontaneous generation.
Abiotic
Absence of living organisms.
.
Abiotic Stresses
The stress caused (e.g., to crop plants) by nonliving,
environmental factors such as cold, drought, flooding, salinity, ozone,
toxic-to-that-organism metals (e.g., aluminum, for plants), and ultraviolet-B
light.
Abrin
A toxin derived from the seed of the rosary pea. See also RICIN,
PHYTOCHEMICALS, TOXIN.
Abscisic Acid
A phytohormone (plant hormone) utilized to control: the size of
stomatal pores — i.e., the openings in leaves through which plants exchange oxygen
and carbon dioxide (and water inadvertently) with the atmosphere; abscision
(e.g., shedding of flowers, fruit, etc.); dormancy. See also PLANT HORMONE,
GPA1.
Absolute Configuration
The configuration of four different substituent groups around an asymmetric
carbon atom, in relation to D- and L-glyceraldehyde. See also DEXTROROTARY (D)
ISOMER, LEVOROTARY (L) ISOMER.
Absorbance (A)
A measure of the amount of light absorbed by a substance suspended
in a matrix. The matrix may be gaseous, liquid, or solid in nature. Most
biologically active compounds (e.g., proteins) absorb light in the ultraviolet
(UV) or visible light portion of the spectrum. Absorbance is used to quantitate
(measure) the concentration of the substance in question (e.g., substance dissolved
in a liquid). See also OPTICAL DENSITY (OD), SPECTROPHOTOMETER.
Absorption
From the Latin ab, away, and sorbere, to suck into. The taking-up of nutrients, water, etc. by
assimilation (e.g., transport of the products of digestion from the intestinal tract across the cell
membranes that comprise the gut, and into the blood). See also “ADME” TESTS, DIGESTION
(WITHIN ORGANISMS).
Abzymes
Catalytic antibodies that are synthetic constructs. They either
stabilize the transition state of a chemical reaction or bind to a specific
substrate, thereby increasing the reaction rate of that chemical reaction. See also
CATALYTIC ANTIBODY, TRANSITION STATE, SUBSTRATE (CHEMICAL).
Ac-CoA
Abbreviation for Acetyl-coenzyme A. Ac-CoA is a chemical
synthesized in cell mitochondria by combining the thiol (molecular group) of
coenzyme A with an acetyl group (i.e., from breakdown/digestion of fats,
carbohydrates, or proteins). See also COENZYME, COENZYME A, FATS,
ACETYLCHOLINE, GLUCONEOGENESIS, ACETYL-CoA CARBOXYLASE, CHOLINESTERASE, CELL,
MITOCHONDRIA, FATS, PROTEIN.
Ac-P
Acetylphosphate.
ACC
Abbreviation/acronym for the compound 1-aminocyclopropane-1-carboxylic
acid, which is produced from S-adenosylmethionine (SAM) in the fruit of certain
plants. When the “sam-k” gene is inserted into the genome of those plants, the
level of SAM is greatly reduced in their fruit, which inhibits (slows)
ripening/softening of that fruit via a reduction/slowdown in production of
ethylene (hormone that causes fruit to ripen/soften). See also ACC SYNTHASE,
ETHYLENE, SAM-K GENE, GENETIC ENGINEERING, GENOME, PLANT HORMONE.
ACC Synthase
Aminocyclopropane carboxylic acid synthase/deaminase; it is one of
the most critical enzymes in the metabolic pathway that creates the hormone
ethylene inside fruit. Because ethylene causes certain fruit (e.g., tomatoes)
to ripen (soften), it is possible to significantly delay the softening (i.e., spoilage)
process by controlling creation of ACC synthase via manipulation of the ACC synthase
gene. See also ACC, METABOLISM, ENZYME, METABOLITE, INTERMEDIARY METABOLISM, PATHWAY,
PLANT HORMONE, POLYGALACTURONASE (PG), ETHYLENE, SAM-K GENE.
ACCase
See ACETYL-CoA CARBOXYLASE.
Acceptor Control
The regulation of the rate of respiration by the availability of
ADP as phosphate acceptor. See also RESPIRATION, ADENOSINE DIPHOSPHATE (ADP).
Acceptor Junction Site The junction between the right 3′ end of an intron and the left 5′ end of an exon. See
also INTRON, EXON. Accession The addition of germ-plasm deposits to existing germ-plasm storage
bands. See also AMERICAN TYPE CULTURE COLLECTION (ATCC).
Acclimatization
The biological process whereby an organism adapts to a new
environment. For example, the body of a mountain climber who has spent
significant time high on Mount Everest (e.g., 20,000 feet above sea level)
produces twice as many red blood cells (to transport oxygen) as it does at sea
level. Often, this adaptation actually occurs on a molecular level. One example
is when natural microorganisms adapt so that they feed on, and degrade, toxic
chemical wastes; or change from using one sugar as a fuel source to another.
See also SUGAR MOLECULES, CATABOLISM, RED BLOOD CELLS, COLD HARDENING,
PHARMACOENVIROGENETICS.
ACE
Angiotensin-converting enzyme. A crucial enzyme (within the human
vascular system) for catalyzing the formation of angiotensin, a hormone that
causes narrowing/ restriction of blood vessels, thus increasing the body’s
blood pressure as the blood is squeezed through those narrowed blood vessels.
The action of ACE can be inhibited by the pharmaceuticals known as ACE
inhibitors. Research indicates that consumption of whey protein can also result
in inhibition of ACE. See also ENZYME, HORMONE, ACE INHIBITORS.
ACE Inhibitors A family of chemically-similar pharmaceuticals utilized to lower
blood pressure in humans, by blocking formation of a hormone (angiotensin) that
narrows/ restricts blood vessels. See also ACE.
Acetolactate Synthase
See ALS.
Acetyl Carnitine
One of the metabolites of mitochondria, it is a substrate (i.e.,
substance that is acted upon) for acylcarnitine transferase (which converts the
acetyl carnitine to carnitine). Research indicates that consumption of acetyl
carnitine helps increase the levels of acetylcholine and nerve growth factor (NGF)
in the brain. See also METABOLITE, MITOCHONDRIA, ACYLCARNITINE TRANSFERASE, SUBSTRATE
(CHEMICAL), CARNITINE, ACETYLCHOLINE, NERVE GROWTH FACTOR (NGF).
Acetyl Coenzyme A
See Ac-CoA.
Acetyl-CoA
Acetyl-coenzyme A. See also Ac-CoA.
Acetyl-CoA Carboxylase
An enzyme that catalyzes the chemical reaction (i.e., conversion of
Ac-CoA to malonyl CoA via carboxylation) which is the first step in the series of
chemical reactions through which some plants manufacture oils (e.g., soybean
oil, canola oil, etc.). See also ENZYME, FATS, SOYBEAN OIL, CANOLA.
Acetylcholine
A neurotransmitter (i.e., one of several relatively small,
diffusible molecules utilized by the human body to “transmit” nerve impulses)
that is synthesized (manufactured) near the ends of axons (i.e., one type of
neuron). That synthesis is accomplished by the “transfer” of an acetyl group (portion
of molecule) from Ac-CoA to a choline molecule (available in the body via
consumption of soybean lecithin or certain other foods), in a chemical reaction
catalyzed by cholinesterase. Increased amounts of acetylcholine in the (human)
brain has been shown to reduce the symptoms of Alzheimer’s disease. See also
NEUROTRANSMITTER, NEURON, CHOLINE, Ac-CoA, LECITHIN, ALZHEIMER’S DISEASE, THYMUS,
ENZYME, CHOLINESTERASE.
Acetylcholinesterase
An enzyme that hydrolyzes (cuts into smaller pieces) molecules of the
neurotransmitter acetylcholine, after the acetylcholine molecules have
accomplished “transmission” of a nerve impulse. That hydrolysis (cutting into
pieces) of acetylcholine molecules thus serves to prepare the neurons (cells of
the body’s nervous system) to be able to transmit other, later nerve impulses.
See also ENZYME, HYDROLYSIS, NEUROTRANSMITTER, ACETYLCHOLINE, NEURON.
Acid
A substance that contains hydrogen atom(s) in its molecular
structure, with a pH in the range from 0–6, which will react with a base to
form a salt. Acids normally taste sour and feel slippery. For example, food product
manufacturers often add citric acid, malic acid, fumaric acid, and itaconic
acid in order to impart a sharp taste to food products. See also BASE, CITRIC
ACID, FUMARIC ACID (C4H4O4).
Acidic Fibroblast Growth Factor (AFGF)
See FIBROBLAST GROWTH FACTOR (FGF).
Acidosis
A metabolic condition in which the capacity of the body to buffer
changes in pH is diminished. Hence, acidosis is accompanied by decreased blood
pH (i.e., the blood becomes more acidic than is normal).
ACP (acyl carrier protein)
A protein that binds acyl intermediates during the formation of
long-chain fatty acids. ACP is important in that it is involved in every step
of fatty acid synthesis. See also FATTY ACID, ACYL-CoA, FATS.
Acquired Immune Deficiency Syndrome (AIDS)
A disease in which a specific virus attacks and kills
macrophages and helper T cells (thus causing collapse of the entire immune system). Once
the immune system has been inactivated, other diseases, which under normal
circumstances can be fought off, become fatal. See also HUMAN IMMUNODEFICIENCY VIRUS TYPE 1 (HIV-1),
HUMAN IMMUNODEFICIENCY VIRUS TYPE 2 (HIV-2), HELPER T CELLS (T4 CELLS), MACROPHAGE, TUMOR NECROSIS FACTOR
(TNF).
Acrylamide Gel
See POLYACRYLAMIDE GELS.
ACTH [adrenocorticotropic hormone (corticotropin)]
A polypeptide secreted by the anterior lobe of the pituitary gland.
This is an example of a protein hormone. See also POLYPEPTIDE (PROTEIN),
ENDOCRINE GLANDS, ENDOCRINE HORMONES.
Activation Energy
The amount of energy (calories) required to bring all the
molecules in one mole of a reacting substance to the transition state. More
simply, it may also be viewed as the energy required to bring reacting molecules
to a certain energy state from which point the reaction proceeds spontaneously.
See also TRANSITION STATE (IN A CHEMICAL REACTION), MOLE, FREE ENERGY.
Activator
A small molecule that stimulates (increases) an enzyme’s catalytic
activity when it binds to an allosteric site. See also ENZYME, EFFECTOR,
ALLOSTERIC SITE.
Active Site
The region of an enzyme surface that binds the substrate molecule
and transforms the substrate molecule into the new (chemical) product (entity).
This site is usually located not on a protruding portion of the enzyme, but
rather in a cleft or depression. This establishes a controlled environment in
which the chemical reaction may occur. See also CATALYTIC SITE, AGONISTS, PHARMACOPHORE,
SUBSTRATE (CHEMICAL), ENZYME, ANTAGONISTS.
Active Transport
Cell-mediated, energy requiring translocation of a molecule across
a membrane in the direction of increasing concentration (i.e., opposite of natural
tendency). See also OSMOTIC PRESSURE.
α-Helix
See ALPHA HELIX.
A.flavus
See ASPERGILLUS FLAVUS.
Activity Coefficient
The factor by which the concentration of a solute must be
multiplied to give its true thermodynamic activity.
Acuron™ Gene
A gene, trademarked by Syngenta AG, that can be inserted into
plants via genetic engineering techniques. Inserted into the genome (DNA) of a
plant, the gene confers tolerance to herbicide(s) whose active ingredient is
protoporphyrinogen oxidase inhibitor (thus, such herbicides are known as PPO
inhibitors). See also HERBICIDE-TOLERANT CROP, GENE, GENETIC ENGINEERING, GENOME,
DEOXYRIBONUCLEIC ACID (DNA).
Acute Transfection
Short-term infection of cells with DNA.
Acyl-CoA
Acyl derivatives of coenzyme A (acyl-S-CoA). See also CARNITINE,
COENZYME A, TRYPSIN INHIBITORS.
Acylcarnitine Transferase
An enzyme that converts the mitochondrial metabolite acetyl carnitine
into carnitine. See also ENZYME, ACETYL CARNITINE, CARNITINE.
AD
An acronym referring to the group of diseases known collectively
as Autoimmune Disorders. These include diseases such as multiple sclerosis,
lupus, rheumatoid arthritis, etc. See also AUTOIMMUNE DISEASE, MULTIPLE SCLEROSIS,
LUPUS.
Adaptation
Refers to the adjustment of a population of organisms to a changed
environment. For example, during the 19th century, the Industrial Revolution
caused large black soot deposits on the white bark of certain trees in England.
The change in environment resulted in adaptation (e.g., via selective breeding)
of a particular indigenous moth population, consisting of a mixture of
all-white and all-black members. Because the soot blackened the formerly white
bark of the trees
on which the moths rested, predatory birds were able to easily
catch and eat the all-white members of the population. Thus, there were fewer
all-white moths present in the breeding
population, and a preponderance of all-black members. During the
20th century, antipollution efforts in England resulted in a cessation of the
airborne soot and the return of tree bark to its original white color. Because
the predatory birds were now able to catch and eat the all-black members of
that moth population more easily, the proportion of all-black and all-white
moths in the breeding population once again changed. See also ORGANISM.
Adaptive Enzymes
See INDUCIBLE ENZYMES.
ADBF
See AZUROPHIL-DERIVED BACTERICIDAL FACTOR (ADBF).
Additive Genes
Genes that interact but do not show dominance (in the case of
alleles) or epistasis (if they are not alleles). See also GENE, ALLELE,
DOMINANT ALLELE, EPISTASIS.
Adenylate Cyclase
The enzyme (within cells) that catalyzes the synthesis
(manufacture) of cyclic AMP. See also CYCLIC AMP.
Adenine A purine base, 6-aminopurine, occurring in ribonucleic acid (RNA)
as well as in deoxyribonucleic acid (DNA) and a component of adenosine
diphosphate (ADP) and adenosine triphosphate (ATP). Adenine pairs with thymine
in DNA and uracil in RNA. See also BASE (NUCLEOTIDE), BASE PAIR (bp), RIBONUCLEIC
ACID (RNA), DEOXYRIBONUCLEIC ACID (DNA).
Adenosine Diphosphate (ADP)
A ribonucleoside 5′-diphosphate serving as phosphategroup acceptor in the cell energy
cycle. See also CATABOLISM, ADENOSINE TRIPHOSPHATE (ATP), ADENOSINE
MONOPHOSPHATE (AMP).
Adenosine Monophosphate (AMP)
A ribonucleoside 5′-monophosphate that is formed by hydrolysis of ATP or ADP. See
also HYDROLYSIS, ADENOSINE DIPHOSPHATE (ADP), ADENOSINE TRIPHOSPHATE (ATP).
Adenosine Triphosphate (ATP)
The major carrier of chemical energy in the cells of all living
things on this planet. A ribonucleoside 5′-triphosphate functioning as a phosphategroup
donor in the energy cycle of the cell, ATP contains three phosphate/oxygen
molecules linked together. When a phosphatephosphate bond in ATP is broken
(hydrolyzed), the energy produced can be used by the cell to carry out its
functions. Thus, ATP serves as the universal medium of biological energy
storage and exchange in living cells. See also ATPase, ATP SYNTHETASE,
HYDROLYSIS, CYCLIC PHOTOPHOSPHORYLATION, BIOLUMINESCENCE, ATP SYNTHASE,
ADENOSINE MONOPHOSPHATE (AMP).
Adenovirus
A type of virus that can infect humans. As with all viruses, it
can reproduce only inside living cells (of other host, organisms). Adenovirus
causes manufacture of a protein (metabolite) that disables the p53 gene.
Because the p53 gene then cannot perform its usual function (i.e., prevention
of uncontrolled cell growth caused by virus/DNA damage), the adenovirus takes over
and causes the cell to make numerous copies of the virus until the cell dies,
thus releasing the virus copies into the body of the host organism to cause
further infection. See also VIRUS, RETROVIRUSES, GENE DELIVERY, GENE THERAPY,
CELL, PROTEIN, p53 GENE, DEOXYRIBONUCLEIC ACID (DNA).
Adhesion Molecule
From the Latin adhaerere, to stick to, the term adhesion molecule refers to a glycoprotein
(oligosaccharide) molecular chain that protrudes from the surface membrane of
certain cells, causing cells possessing matching adhesion molecules to adhere
to each other. For example, in 1952 Aaron Moscona observed that (harvesting enzyme-separated)
chicken embryo cells did not remain separated, but instead coalesced again into
an (embryo) aggregate. In 1955, Philip Townes and Johannes Holtfreter showed
that like amphibian (e.g., frog) neuron cells will rejoin after being
physically separated (e.g., with a knife blade); but unlike cells remain
segregated (apart). Adhesion molecules also play a crucial role in guiding
monocytes to sources of infection (e.g., pathogens) because adhesion molecules
in the walls of blood vessels (after activation caused by pathogen invasion of adjacent
tissue) adhere to like adhesion molecules in the membranes of monocytes in the blood.
The monocytes pass through the blood vessel walls, become macrophages, and
fight the pathogen infection (e.g., triggering tissue inflammation, etc.). See
also OLIGOSACCHARIDES, MONOCYTES, MACROPHAGE, POLYPEPTIDE (PROTEIN), CELL,
PATHOGEN, CD4 PROTEIN, CD44 PROTEIN, GP120 PROTEIN, VAGINOSIS, HARVESTING
ENZYMES, HARVESTING, SIGNAL TRANSDUCTION, SELECTINS, LECTINS, GLYCOPROTEINS,
SUGAR MOLECULES, LEUKOCYTES, LYMPHOCYTES, NEUTROPHILS, ENDOTHELIUM, ENDOTHELIAL
CELLS, P-SELECTIN, ELAM-1, INTEGRINS, CYTOKINES.
Adhesion Protein
See ADHESION MOLECULE, ENDOTHELIAL CELLS.
Adipocytes
Specialized cells within an organism’s lymphatic system that store
the triacylglycerols (also sometimes called triglycerides) after digestion of
those fats, later releasing fatty acids and glycerol into the bloodstream when
needed by the organism. See also CELL, TRIGLYCERIDES, FATTY ACID, DIGESTION
(within organism), FATS.
Adipose
Refers to energy storage tissues consisting of fat molecules
within some animals. Adipose tissue tends to increase if an animal consumes
more energy-containing food than needed for its level of energy expenditure (e.g.,
via exercise). In humans older than 40, an increase in the body’s adipose
tissue is correlated with an increased risk of premature death (e.g., from
coronary heart disease). See also FATS, CORONARY HEART DISEASE (CHD), LEPTIN.
Adjuvant (to a herbicide)
Any compound that enhances the effectiveness (i.e., weedkilling ability)
of a given herbicide. For example, adjuvants such as surfactants can be mixed
(prior to application to weeds) with herbicide (in water), in order to hasten
transport of the herbicide’s active ingredient into the weed plant. That is
because the herbicide must move from an aqueous (water) environment into one
(i.e., the weed plant’s cuticle or “skin”) comprised of lipids/lipophilic molecules,
before it can accomplish its task. See also SURFACTANT, LIPIDS, LIPOPHILIC.
Adjuvant (to a pharmaceutical)
Any compound that enhances the desired response by the body to
that pharmaceutical. For example, adjuvants such as certain polysaccharides or surface-modified
diamond nanoparticles, can be injected along with (vaccine) antigen in order to
increase the immune response (e.g., production of antibodies) to a given
antigen. Another example is that consumption of grapefruit juice by humans will
increase the impact of certain pharmaceuticals. Those pharmaceuticals include
some sedatives, antihypertensives, the antihistamine terfenadine, and the
immunosuppressant cyclosporine. The adjuvant effect of grapefruit juice is
thought to be caused via inhibition of the enzyme cytochrome P4503A4, which
catalyzes reactions involved in the metabolism (breakdown) of those
pharmaceuticals. Another example is that consumption of the pharmaceutical
known as clopidogrel (commercial name Plavix) by people immediately following a
mild heart attack (severe chest pain) — along with aspirin — greatly reduces
the risk of death, strokes, and (new, additional) heart attacks, versus taking
aspirin alone after a mild heart attack. See also CELLULAR IMMUNE RESPONSE,
HUMORAL IMMUNITY, POLYSACCHARIDES, NANOTECHNOLOGY, ANTIGEN, ANTIBODY, ENZYME,
METABOLISM, HISTAMINE, CYCLOSPORINE, CYTOCHROME P4503A4.
ADME
Acronym for Absorption, Distribution (within the body),
Metabolism, and Elimination of pharmaceuticals. See also ADME TESTS, IN SILICO SCREENING.
ADME Tests
Refers to Absorption, Distribution (within the body), Metabolism,
and Elimination tests required by the U.S. Food and Drug Administration (FDA)
for approval of new pharmaceuticals or new food ingredients. See also FOOD AND
DRUG ADMINISTRATION (FDA), ABSORPTION, METABOLISM, INTERMEDIARY METABOLISM,
PHARMACOKINETICS, PHARMACOGENOMICS, CODEX ALIMENTARIUS COMMISSION, ADME, ADMET,
IN
SILICO SCREENING.
ADMET
Acronym for Absorption, Distribution (within the body),
Metabolism, Elimination, Toxicity of pharmaceuticals. See also ADME TESTING, IN SILICO TESTING.
Adoptive Cellular Therapy
The increase in immune response that is achieved by selectively removing
certain immune system cells from a (patient’s) body, multiplying them in vitro outside the body to
increase their
number greatly, then reinserting those (more numerous) immune
system cells into the same body. See also CELLULAR IMMUNE RESPONSE, CELL
CULTURE, IN
VITRO,
GENE DELIVERY, GENE THERAPY, EX VIVO (THERAPY).
Adoptive Immunization
The transfer of an immune state from one animal to another by means
of lymphocyte transfusions. See also LYMPHOCYTE.
ADP
See ADENOSINE DIPHOSPHATE (ADP).
Adventitious
From the Latin adventitius, not properly belonging to. The term can be utilized to refer to:
plant shoots emanating from sites other than typical ones (e.g., from a plant’s
leaves); a small amount of transgenic grain accidentally mixed into other
grain. See also TRANSGENIC.
Aerobe
An organism that requires oxygen to live (respire).
Aerobic
Exposed to air or oxygen. An oxygenated environment.
Affinity Chromatography
A method of separating a mixture of proteins or nucleic acids (molecules)
by specific interactions of those molecules with a component known as a ligand,
which is immobilized on a support. If a solution of, say, a mixture of proteins
is passed over (through) the column, one of the proteins binds to the ligand on
the basis of specificity and high affinity (they fit together like a lock and
key). The other proteins in the solution wash through the column because they
were not able to bind to the ligand. Once the column is devoid of the other
proteins, an appropriate wash solution is passed through the column, which
causes the protein/ligand complex to dissociate. The protein is subsequently collected
in a highly purified form. See also CHROMATOGRAPHY, PROTEIN, NUCLEIC ACIDS,
ANTIBODY AFFINITY CHROMATOGRAPHY, LIGAND (IN CHROMATOGRAPHY).
Aflatoxin
The term that is used to refer to a group of related mycotoxins
(i.e., metabolites produced by fungi that are toxic to animals and humans)
produced by some strains Aspergillus flavus and Aspergillus parasiticus, common fungi that
typically live on decaying vegetation. Corn earworm (Helicoverpa zea) and European corn
borer (Ostrinia nubilalis) are vectors
(carriers) of Aspergillus flavus. Aflatoxin B1 is the most commonly occurring aflatoxin and one of
the most potent carcinogens known to man. When dairy cattle eat
aflatoxin-contaminated feed, their metabolism process converts the aflatoxin
(e.g., Aflatoxin B1) into the mycotoxins known as Aflatoxin M1 and Aflatoxin
M2, which soon appear in the milk produced. Consumption of aflatoxins by humans
can also result in acute liver damage. See also CARCINOGEN, TOXIN, FUNGUS,
MYCOTOXINS, STRESS PROTEINS, LIPOXYGENASE (LOX), PEROXIDASE, HELICOVERPA ZEA (H. zea), BETA CAROTENE,
OH43, BRIGHT GREENISH-YELLOW FLUORESCENCE (BGYF), CORN, EUROPEAN CORN BORER
(ECB).
AFLP
Acronym for Amplified Fragment Length Polymorphism. See also
AMPLIFIED FRAGMENT LENGTH POLYMORPHISM.
Agar
A complex mixture of polysaccharides obtained from marine red
algae. It is also called agar-agar. Agar is used as an emulsion stabilizer in
foods, as a sizing agent in fabrics, and as a solid substrate for the
laboratory culture of microorganisms. Agar melts at 100°C (212°F), and when
cooled below 44°C (123°F) forms a stiff and transparent gel. Microorganisms are
seeded onto and grown (in the laboratory) on the surface of the gel. See also
POLYSACCHARIDES, CULTURE
MEDIUM.
Agarose
A highly purified form of agar used as a stationary phase (substrate)
in some chromatography and electrophoretic methods. See also CHROMATOGRAPHY,
ELECTROPHORESIS, AGAR.
Aging
The process, affecting organisms and most cells, whereby each cell
division (mitosis) brings that cell (or organism composed of such cells) closer
to its final cell division (i.e., death). Notable exceptions to this aging process
include cancerous cells (e.g., myelomas) and the single-celled organism; both
of which are “immortal.” See also TELOMERES, MITOSIS, HYBRIDOMA, MYELOMA,
CANCER.
Aglycon
A nonsugar component of a glycoside. See also GLYCOSIDE.
Aglycone
The biologically active (molecular) form of molecules of
isoflavones. See also ISOFLAVONES, BIOLOGICAL ACTIVITY.
Agonists
Small protein or organic molecules that bind to certain cell proteins
(i.e., receptors) at a site that is adjacent to the cell’s “docking” site of
protein hormones, neurotransmitters, etc. (i.e., receptor) to induce a
conformational change in that cell protein, thereby enhancing its activity
(i.e., effect upon the cell). See also RECEPTORS, ACTIVE SITE, CONFORMATION,
CELL, HORMONE, ANTAGONISTS, NEUROTRANSMITTER.
Agraceutical
See NUTRACEUTICAL, PHYTOCHEMICAL.
Agrobacterium tumefaciens
A naturally occurring bacterium that is capable of inserting its
DNA (genetic information) into plants, resulting in a type of injury to the plant
known as crown gall. In 1980, Marc van Montagu showed that Agrobacterium tumefaciens
could
alter the DNA of its host plant(s) by inserting its own (“foreign”) DNA into the genome
of the host plants (thereby opening the way for scientists to insert virtually any
foreign genes into plants via use of A. tumefaciens). In 1983, Luis Herrera-Estrella
created the first man-made transgenic plant by inserting an antibioticresistant gene into a tobacco
plant. During
2000,
Weija Zhou and Richard Vierling proved that A. tumefaciens is at least 10 times more
effective (i.e., at “infecting” plants to insert DNA) in space (i.e.,
weightlessness/ microgravity) than it is when on the surface of the Earth.
Among others, Monsanto Company has developed a way to stop A. tumefaciens from causing crown
gall, while maintaining its ability to insert DNA into plant cells, and now
uses A.
tumefaciens
as a vehicle to insert desired genes into crop plants (e.g., the gene causing
high production of CP4 EPSP synthase, thus conferring resistance to
glyphosate-containing herbicide). See also BACTERIA, DEOXYRIBONUCLEIC ACID (DNA),
INFORMATIONAL MOLECULES, GENOME, TRANSGENIC (ORGANISM), PROTOPLAST, EPSP SYNTHASE,
CP4 EPSPS, “SHOTGUN” METHOD, BIOLISTIC® GENE GUN, WHISKERS™, GENETIC ENGINEERING,
GENE, BIOSEEDS, GLYPHOSATE, GLYPHOSATE-TRIMESIUM, GLYPHOSATE ISOPROPYLAMINE SALT,
NOS TERMINATOR.
AHG
Antihemophilic Globulin. Also known as FACTOR VIII or
Antihemophilic Factor VIII. See also FACTOR VIII, GAMMA GLOBULIN.
AIDS
See ACQUIRED IMMUNE DEFICIENCY SYNDROME (AIDS).
Alanine (ala)
A nonessential amino acid of the pyruvic acid family. In its dry,
bulk form it appears as a white crystalline solid. See also ESSENTIAL AMINO ACIDS.
Albumin A protein that the liver synthesizes (manufactures). Most minerals
and hormones utilized by the human body are first “attached” to a molecule of
albumin before they are transported in the bloodstream to where they are needed
in the body. See also PROTEIN, HORMONE, SUPERCRITICAL CARBON DIOXIDE.
ALCAR
Acronym for Acetyl-L-Carnitine. See also ACETYL CARNITINE.
Aldose
A simple sugar in which the carbonyl carbon atom is at one end of
the carbon chain. A class of monosaccharide sugars; the molecule contains an
aldehyde group. See also MONOSACCHARIDES.
Aleurone
The layer (“skin”) that covers the endosperm portion of a plant
seed. See also ENDOSPERM.
AlfAFP
Acronym for Alfalfa Antifungal Peptide. See also DEFENSINS.
Algae
A heterogeneous (widely varying) group of photosynthetic plants,
ranging from microscopic single-cell forms to multicellular, very large forms
such as seaweed. All of them contain chlorophyll and hence most are green, but
some may be different colors due to the presence of other, overshadowing
pigments.
Alicin
A compound that is produced naturally by the garlic plant when the
cells within garlic bulbs are broken open (e.g., during food preparation or
consumption). Enzymes present within those garlic cells convert (precursor compound)
to alicin. Research indicates that human consumption of alicin confers some specific
health benefits (anti-thrombotic, reduce blood cholesterol levels, reduce/avoid
coronary heart disease, enhance the immune system, etc.). See also CELL,
PHYTOCHEMICALS, ENZYME, THROMBOSIS, CORONARY HEART DISEASE (CHD), CHOLESTEROL.
Alkaline Hydrolysis
A chemical method of liberating DNA from a DNA-RNA hybrid. See
also HYDROLYSIS, RIBONUCLEIC ACID (RNA), DNA-RNA HYBRID, DEOXYRIBONUCLEIC ACID (DNA).
Alkaloids
A class of toxic compounds that are naturally produced by some
organisms (e.g., ants, certain plants such as lupines, and certain fungi such as ergot). For example, certain
species of ants naturally produce alkaloids, as a self-defense mechanism.
Poison- dart frogs (Dendrobates azureus) and two species of New Guinea songbirds (Pitohui dichrous and Ifrita kowaldi) can tolerate those
ant-produced alkaloids, so they also acquire that self-defense (toxin) by
eating those particular ants. Another example is the moth Utetheisa ornatrix, whose larvae (caterpillars)
feed on certain plants that contain pyrrolizidine alkaloids. Because those
alkaloids are extremely bitter tasting and toxic, spiders that normally prey on
them refuse to eat those Utetheisa ornatrix; even after they later become adult moths.
If those moths (who consumed those pyrrolizidine alkaloids as larvae) get
caught in the spider’s web, the spider will cut it out of the web and release
that particular (toxic) moth. Vinca alkaloids, isolated from the specific
plants that produce them, have been utilized as cancer- treating (antitumor)
drugs. See also
TOXIN, FUNGUS, TREMORGENIC INDOLE ALKALOIDS, ERGOTAMINE.
Allele
From the Greek allelon, mutually each other, the term refers to one of several alternate
forms of a gene occupying a given locus on the chromosome, which controls
expression (of product) in different ways. See also EXPRESS, GENE, CHROMOSOMES,
LOCUS.
Allelic Exclusion
The expression in any particular manner of only one of the alleles
in an antibody gene within a B lymphocyte (cell), coding for the expressed
antibody. See also ALLELE, CODING SEQUENCE, GENE, B LYMPHOCYTES, ANTIBODY,
IMMUNOGLOBULIN.
Allelopathy
Refers to the secretion of certain chemicals (e.g., terpenoid
compounds) by a plant, in order to hinder the growth or reproduction of other
plants growing near it.
Allergies (airborne)
See MAST CELLS.
Allergies (foodborne)
An IgE-mediated (aggressive) immune system response to antigen(s)
present on protein molecules in the particular food to which (a given) person is
allergic. The antibodies (IgE) bind to those antigens and trigger a humoral
immune response that can cause vomiting, diarrhea, skin reactions, wheezing,
and respiratory distress. In severe cases, the immune response can cause death.
In some rare instances, the allergic reaction is mediated by sensitized T
cells. In some rare instances, the onset of a food allergy incident is induced
by exercise (before or after eating that particular food). The U.S. Food and
Drug Administration (FDA) requires testing in advance to determine if a
genetically engineered foodstuff has the potential to cause allergic reactions in
humans, before that genetically engineered foodstuff (e.g., a modified crop
plant) is approved by the FDA. In general, known food allergens (e.g., peanuts,
Brazil nuts, wheat, etc.) are protein molecules that are resistant to rapid
digestion (because those protein molecules are too tightly “folded together”
for digestive enzymes to access their chemical bonds to break down). One potential
way to genetically engineer currently allergenic crops (e.g., wheat) to make them
less allergenic, is to insert gene(s) for extra production of thioredoxin.
Found in all living organisms, thioredoxin is a protein that targets and breaks
down the chemical bonds holding together a tightly folded together protein
molecule (thereby making those protein molecules easier to digest). Future
crops engineered to contain more thioredoxin than the traditional average level
may be nonallergenic. See also PROTEIN, PROTEIN FOLDING, ANTIBODY, ANTIGEN,
FOOD AND DRUG ADMINISTRATION (FDA), GENETIC ENGINEERING, IMMUNOGLOBULIN,
HUMORAL IMMUNITY, MAST CELLS, LEUKOTRIENES, DIGESTION (WITHIN
ORGANISMS), ORGANISM.
Allicin
See ALICIN.
Allogeneic
With a different set of genes (but same species). For example, an
organ transplant from one nonrelated human to another is allogeneic. An organ
transplant from a baboon to a human would be xenogeneic. See also GENE,
SPECIES, XENOGENEIC ORGANS.
Allosteric Enzymes
Regulatory enzymes whose catalytic activity is modulated by the noncovalent
binding of a specific metabolite (effector) at a site (regulatory site) other
than the catalytic site (on the enzyme). Effector binding causes a
three-dimensional conformation change in the enzyme and is the root of the
modulation. The term allosteric is used to differentiate this form of
regulation from the type that may result from the competition between substrate
and inhibitors at the catalytic site. See also ENZYME, STERIC HINDRANCE, EFFECTOR,
CONFORMATION, ACTIVE SITE.
Allosteric Site
The site on an (allosteric) enzyme molecule where, via noncovalent
binding to the site, a give effector can increase or decrease that enzyme’s
catalytic activity. Such an effector is called an allosteric effector because
it binds at a site on the enzyme molecule that is other (allo) than the enzyme’s
catalytic site. See also ALLOSTERIC ENZYMES, ACTIVATOR, CATALYTIC SITE,
EFFECTOR, CONFORMATION, ENZYME, METABOLITE, CATALYST.
Allotypic Monoclonal Antibodies
Monoclonal antibodies that are isoantigenic. See also MONOCLONAL
ANTIBODIES (MAb), ANTIGEN.
Allozyme
See ALLOSTERIC ENZYMES.
Aloe vera L.
A plant whose sap (juice) contains certain carbohydrates that
naturally assist healing of human skin (wounds). Those carbohydrates “activate”
macrophages, which cause those macrophages to produce cytokines (that regulate
human immune system and inflammatory responses which promote healing). See also
PHYTOCHEMICALS, CARBOHYDRATES (SACCHARIDES), MACROPHAGE, CYTOKINES.
Alpha Amylase Inhibitor-1
A protein naturally produced in the seeds of the plant known as
the common bean Phaseolus vulgaris that inhibits the amylase enzyme in the gut
of the pest insect known as the pea weevil. Because the amylase enzyme (in its
gut) is inhibited (prevented from helping digestion) by the Alpha Amylase
Inhibitor-1, the seeds of the P. vulgaris plant are protected
from depradation by the pea weevil. See also PROTEIN, ENZYME, AMYLASE, WEEVILS.
Alpha Galactosides
Term referring to a family of polysaccharides (produced in plant seeds)
composed (at the molecular level) of one sucrose unit linked by a 1,6 molecular
bond to several galactose units. Alpha galactosides include raffinose,
stachyose, and verbascose. See also POLYSACCHARIDES, GALACTOSE (GAL),
STACHYOSE.
Alpha Helix (α-helix) A highly regular (i.e., repeating) structural feature that occurs
in certain large molecules. First discovered in protein molecules by Linus
Pauling in the late 1940s. See also A-DNA, PROTEIN, PROTEIN FOLDING, PROTEIN
STRUCTURE.
Alpha Interferon
Also written as α-interferon,
it has been shown to prolong life and reduce tumor size in patients suffering
from Kaposi’s sarcoma (a cancer that affects approximately 10% of people with
acquired immune deficiency syndrome). It is also effective against hairy-cell
leukemia and may work against other cancers. It has recently been approved by
the U.S. FDA for use against certain types of sarcoma. Recent research
indicates that injections of alpha interferon can limit the liver damage
typically caused by hepatitis C, a viral disease. See also INTERFERONS.
ALS
A plant enzyme (also present in some microoganisms) known as
acetolactate synthase or acetohydroxy acid synthase. ALS catalyzes (enables to
occur) one of the early chemical reaction steps in the synthesis (manufacturing)
of branched-chain amino acids (isoleucine, leucine, valine) required by plants
to sustain life (i.e., to make needed proteins). Herbicides that
deactivate/destroy ALS are effective at killing plants (e.g., weeds). See also
ENZYME, GENE, ALS GENE, MICROORGANISMS, CATALYST, AMINO ACID, ISOLEUCINE (ile),
LEUCINE (leu), VALINE (val).
ALS Gene
Gene that codes for (i.e., causes to be produced in microorganisms
or plants’ chloroplasts) the critical-to-plants enzyme acetolactate synthase
(ALS). See also GENE, HTC, MICROORGANISMS, CHLOROPLASTS, ENZYME, CATALYST,
AMINO ACID, ISOLEUCINE (ile), LEUCINE (leu), VALINE, STS SULFONYLUREA
(HERBICIDE)- TOLERANT SOYBEANS.
Alternative mRNA Splicing
See TRANSCRIPTOME, CENTRAL DOGMA (NEW).
Alternative Splicing See TRANSCRIPTOME, CENTRAL DOGMA (NEW).
Alu Family
A set of dispersed and related genetic sequences, each about 300
base pairs long, in the human genome. At both ends of these 300 bp segments
there is an A-G-C-T sequence. Alu 1 is a restriction enzyme that recognizes
this sequence and cleaves (cuts) it between the G (guanine) and the C
(cytosine). See also GENOME, RESTRICTION ENDONUCLEASES.
Aluminum Resistance
See CITRATE SYNTHASE (CSb) GENE, GENE, CITRIC ACID.
Aluminum Tolerance
See CITRATE SYNTHASE (CSb) GENE, GENE, CITRIC ACID.
Aluminum Toxicity
See CITRATE SYNTHASE (CSb) GENE, GENE, CITRIC ACID.
Alzheimer’s Disease
Named after Alois Alzheimer who, in 1906, first described the Amyloid
β Protein (AβP) plaques in the human
brain that are caused by this disease. Alzheimer’s disease causes progressive memory
loss and dementia in its victims as it kills brain cells (neurons). Some drugs (e.g.,
tacrine, donepezil, etc.) appear to slow the progression of Alzheimer’s disease
(by increasing the availability of acetylcholine in the brain), but there is
currently no way to stop the disease. See also AMYLOID β PROTEIN (AβP), AMYLOID β PROTEIN PRECURSOR (AβPP), NEURON,
NEUROTRANSMITTER, ACETYLCHOLINE, OXIDATIVE STRESS.
AMD
Acronym for Age-related Macular Degeneration. See also LUTEIN.
American Society for Biotechnology (ASB)
A society founded for the purpose of “providing a multi- and
interdisciplinary forum for those persons from academia, industry, and
government who are interested in any and all aspects of biotechnology, and will
achieve its aims by cooperation with existing organizations active in the
field.” To join, write to ASB, P.O. Box 2820, Sausalito, California, 94966-2820.
See also BIOTECHNOLOGY, INTERNATIONAL SOCIETY FOR THE ADVANCEMENT OF
BIOTECHNOLOGY (ISAB), BIOTECHNOLOGY INDUSTRY ORGANIZATION (BIO).
American Type Culture Collection (ATCC)
An independent, nonprofit organization established in 1925 for the
preservation and distribution of reference cultures. See also CELL CULTURE,
CULTURE, CULTURE MEDIUM, TYPE SPECIMEN, CONSULTATIVE GROUP ON INTERNATIONAL AGRICULTURAL
RESEARCH (CGIAR).
Ames Test
A simple bacterial-based carcinogens test that was developed by
Bruce Ames in 1961. Although this test evaluates mutagenesis (causation of
mutations) in the DNA of bacteria, its results have been utilized to approve or
not approve certain compounds for consumption by humans. See also BIOASSAY,
BACTERIA, ASSAY, MUTUAL RECOGNITION AGREEMENTS (MRAs), GENOTOXIC CARCINOGENS, CARCINOGEN,
PARP.
Amino Acid
There are 20 common amino acids, each specified by a different
arrangement of three adjacent DNA nucleotides. These are the building blocks of
proteins. Joined together in a strictly ordered chain, the sequence of amino
acids determines the character of each protein (chain) molecule. The 20 common
amino acids are: alanine, arginine, aspartic acid, glutamic acid, glutamine,
glycine, histidine, isoleucine, leucine, phenylalanine, proline, serine,
threonine, tryptophan, tyrosine, valine, cysteine, methionine, lysine, and
asparagine. Note that virtually all of these amino acids (except glycine) possess
an asymmetric carbon atom, and thus are potentially chiral in nature. See also
PROTEIN, POLYPEPTIDE (protein), STEREOISOMERS, CHIRAL COMPOUND, MESSENGER RNA (mRNA),
ESSENTIAL AMINO ACIDS, DEOXYRIBONUCLEIC ACID (DNA), ABSOLUTE CONFIGURATION.
Amino Acid Profile
Also known as “protein quality,” this refers to a quantitative
delineation of how much of each amino acid is contained in a given source of
(livestock feed or food) protein. For example, the amino acid profile of
soybean meal is matched closest to the profile of amino acids needed for human
nutrition, of all protein meals. See also “IDEAL PROTEIN” CONCEPT, PROTEIN,
AMINO ACID, SOYBEAN MEAL, PDCAAS.
Aminocyclopropane Carboxylic Acid Synthase/ deaminase
See ACC SYNTHASE, ACC.
AMP
See ADENOSINE MONOPHOSPHATE (AMP).
Amphibolic Pathway
A metabolic pathway used in both catabolism and anabolism. See also
ANABOLISM, CATABOLISM.
Amphipathic Molecules
Molecules bearing both polar and nonpolar domains (within the same
molecule). Some examples of amphipathic molecules are wetting agents (SDS), and
membrane lipids such as lecithin. See also MICELLE, REVERSE MICELLE (RM),
POLARIT(CHEMICAL).
Amphiphilic Molecules
Also known collectively as amphiphiles, these molecules possess distinct
regions of hydrophobic (“water hating”) and hydrophilic (“water loving”) character
within the same molecule. When dissolved in water above a certain concentration
(known as the CMC), they are capable of forming high molecular weight
aggregates, or micelles. See also CRITICAL MICELLE CONCENTRATION, HYDROPHOBIC,
HYDROPHILIC, MICELLE, REVERSE MICELLE (RM).
Amphoteric Compound
A compound capable of both donating and accepting protons and thus
able to act chemically as either an acid or a base.
Amplicon
A specific sequence of DNA produced by a DNA-amplification
technology such as the Polymerase Chain Reaction (PCR) technique. See also
DEOXYRIBONUCLEIC ACID (DNA), SEQUENCE (OF A DNA MOLECULE), POLYMERASE CHAIN
REACTION (PCR) TECHNIQUE, NESTED PCR.
Amplification
The production of additional copies of a chromosomal sequence,
found as either intrachromosomal or extrachromosomal DNA. See also IN VITRO SELECTION.
Amplified Fragment Length Polymorphism
Also known by its acronym, AFLP is a “DNA marker” utilized in a
“genetic mapping” technique which employs the specific sequence of bases
(nucleotides) in a piece of DNA (from an organism). Since the specific sequence
of bases in their DNA molecules is different for each species, strain, variety,
or individual (due to DNA polymorphism), AFLP can be used to “map” those DNA molecules
(e.g., to assist and speed up plant breeding programs). See also GENETIC MAP, SEQUENCE
(OF A DNA MOLECULE), DEOXYRIBONUCLEIC ACID (DNA), GENOME, PHYSICAL MAP (OF
GENOME), MARKER (DNA SEQUENCE), MARKER (GENETIC MARKER), POLYMORPHISM (CHEMICAL),
NUCLEIC ACIDS, NUCLEOTIDE, GENETIC CODE.
Amplimer
See AMPLICON.
Amylase
A term that is used to refer to a category of enzymes that
catalyzes the chemical reaction in which amylose (starch) molecules are
hydrolytically cleaved (broken) to molecular pieces (e.g., the polysaccharides maltose,
maltotriose, a-dextrin, etc.). For example, α-amylase is used to break apart corn starch molecules in the first
step of manufacturing fructose (sweetener for soft drinks). Since 1857, amylase
has been utilized to remove (amylose) starch from woven fabrics in the textile
industries. Modern uses of some amylases include enabling the substitution of
barley grain for malt in the beer brewing process. See also ENZYME, STARCH,
AMYLOSE, BARLEY, HYDROLYTIC CLEAVAGE, POLYSACCHARIDES, ALPHA AMYLASE
INHIBITOR-1.
Amyloid β Protein Precursor (AβPP)
A (collective) set of protein molecules, from which are derived
Amyloid β Protein (AβP). See also PROTEIN,
AMYLOID β PROTEIN PRECURSOR (AβPP).
AmyloidβProtein (AβP)
A small protein that forms plaque in the brains and in the brain blood
vessels of victims of Alzheimer’s disease. AβP forms cation-selective ion channels in lipid bilayers (e.g.,
membranes surrounding cells). This ion channel formation disrupts calcium
homeostasis, allowing (destructive) high concentrations of calcium ions in
brain cells. See also PROTEIN, AMYLOID β PROTEIN PRECURSOR (AβPP), ALZHEIMER’S DISEASE.
Amyloid Placques
See AMYLOID β PROTEIN
(AβP).
Amylopectin
The form of starch (molecule) that consists of multi-branched
polymers, containing approximately 100,000 glucose units per molecule
(polysaccharide). See also STARCH, POLYMER, GLUCOSE (GLc), POLYSACCHARIDES,
WAXY CORN.
Amylose
The form of starch that consists of unbranched polymers,
containing approximately 4000 glucose units per molecule (polysaccharide). It
is present in potatoes at 23–29% content (variation is thought to be caused by
different growing conditions). See also POLYMER, GLUCOSE (GLc), AMYLASE, POLYSACCHARIDES.
Anabolism
The phase of intermediary metabolism concerned with the
energy-requiring biosynthesis of cell components from smaller precursor
molecules. See also CATABOLISM, ASSIMILATION, METABOLISM, CELL, PLASMA
MEMBRANE.
Anaerobe
An organism that lives in the absence of oxygen and generally
cannot grow in the presence of oxygen. The catabolic metabolism of anaerobic
microorganisms reduces a variety of organic and inorganic compounds in order to
survive (e.g., carbon dioxide, sulfate, nitrate, fumarate, iron, manganese);
anaerobes produce a large number of end products of metabolism (e.g., acetic
acid, propionic acid, lactic acid, ethanol, methane, etc.). See also
CATABOLISM, METABOLISM, METABOLITE, REDUCTION (IN A CHEMICAL REACTION),
ANAEROBIC.
Anaerobic
An environment without air or oxygen. See also ANAEROBE.
Analogue (Analog)
A compound (or molecule) that is a (chemical) structural
derivative of a parent compound. The word is also used to describe a molecule
that may be structurally similar (but not identical) to another, and which
exhibits many or some of the same biological functions of the other. For
example, the large class of antibiotics known as the sulfa drugs are all
analogues of the original synthetic chemical drug (known as Prontosil, which
cures streptococcal infections) discovered by the German biologist Gerhart
Domagk. His discovery and others made possible a program of further chemical syntheses
based upon the original (sulfanilamide) molecular structure and resulted in the
large number of sulfonamide (also called “sulfa”) drugs available today. All of
the analogue (also analog) sulfa drugs that were patterned after the original
sulfanilamide molecular structure may be called sulfanilamide analogues. Today,
analogues are known by man for various vitamins, amino acids, purines, sugars, growth
factors, and many other chemical compounds. Research chemists produce analogues
of various molecules in order to ascertain the biological role of, or
importance of, certain structures (within the molecule) to the molecule’s
function within a living organism. See also BIOMIMETIC MATERIALS, RATIONAL DRUG
DESIGN, HETEROLOGY, GIBBERELLINS, QUANTITATIVE STRUCTURE-ACTIVITY RELATIONSHIP
(QSAR).
ANDA (to FDA)
Abbreviated New Drug Application (to the U.S. Food and Drug Administration).
See also NDA, “TREATMENT” IND REGULATIONS, FOOD AND DRUG ADMINISTRATION (FDA).
Angiogenesis
Formation/development of new blood vessels in the body. Discovered
to be triggered and stimulated by angiogenic growth factors, in the early
1980s. Angiogenesis is required for malignant tumors to metastasize (spread throughout
the body), because it provides the (newly-created) blood supply that tumors
require. Angiogenesis is also crucial to the development of glaucoma and
macular degeneration (major cause of blindness). The drug Thalidomide is a potent
inhibitor of angiogenesis, as are the proteins angiostatin and endostatin. See
also ANGIOGENIC GROWTH FACTORS, TUMOR, CANCER, METASTASIS, ANTIANGIOGENESIS,
CHIRAL
COMPOUND, ANGIOSTATIN, ENDOSTATIN.
Angiogenesis Factors
See ANGIOGENIC GROWTH FACTORS.
Angiogenic Growth Factors
Proteins that stimulate formation of blood vessels (e.g., in tissue
being formed by the body to repair wounds). See also FILLER EPITHELIAL CELLS, FIBROBLAST
GROWTH FACTOR (FGF), MITOGEN, ANGIOGENIN, ENDOTHELIAL CELLS, TRANSFORMING GROWTH
FACTOR-ALPHA (TGF-ALPHA), TRANSFORMING GROWTH FACTOR-BETA (TGFBETA),
PLATELET-DERIVED GROWTH FACTOR (PDGF), ANGIOGENESIS.
Angiogenin
One of the human angiogenic growth factors, it possesses potent
angiogenic (formation of blood vessels) activity. In addition to stimulating
(normal) blood vessel formation, angiogenin levels are correlated with placenta
formation and tumor growth (tumors require new blood vessels). See also
ANGIOGENIC GROWTH FACTORS, ANGIOGENESIS, TUMOR, GROWTH FACTOR.
Angiostatin
An antiangiogenesis (anti-blood vessel- formation) human protein
discovered by Judah Folkman. In combination with endostatin, it has been shown
to cause certain cancer tumors in mice to shrink by cutting off the creation of
new blood vessels required to “feed” a growing tumor. Angiostatin acts to halt
the creation of new blood vessels by binding to ATP synthase (an enzyme needed
to initiate new blood vessels). See also PROTEIN, ANTIANGIOGENESIS, ENDOSTATIN,
CANCER, ATP SYNTHASE, TUMOR.
Angstrom (Å)
10–8 cm (3.937 × 10–9 inch or 10-10 m).
Anion
See ION.
Anneal
The process by which the complementary base pairs in the strands
of DNA combine. See also BASE PAIR (bp), DEOXYRIBONUCLEIC ACID (DNA).
Anonymous DNA Marker
Refers to a DNA marker with a clearly identifiable sequence variation
(i.e., it is detectable by the specific variation in its DNA sequence, whether
or not it occurs in or near a coding sequence). See also DEOXYRIBONUCLEIC ACID
(DNA), SEQUENCE (OF A DNA MOLECULE), MARKER (DNA SEQUENCE), MICROSATELLITE DNA.
Antagonists
Molecules that bind to certain proteins (e.g., receptors, enzymes)
at a specific (active) site on that protein. The binding suppresses or inhibits
the activity (function) of that protein. See also RECEPTORS, ACTIVE SITE,
CONFORMATION, AGONISTS, ENZYME, ALLOSTERIC ENZYMES.
Anterior Pituitary Gland
See PITUITARYGLAND.
Anthocyanidins Natural pigments (flavonoids) produced in blueberries (genus Vaccinium), blackberries (Rubus fruticosus), cranberries (Vaccinium
macrocarpon),
cherries (genus Prunus), black or purple carrots (Daucus carota), and some types of
grapes. Consumption of anthocyanidins by humans has been shown to be beneficial
to eyesight by aiding the health of the retina. Within the human body,
anthocyanidins act as antioxidants (i.e., “quenchers” of free radicals), so consumption
apparently reduces the risk of some cancers, coronary heart disease, eyesight loss,
and cataracts. See also PHYTOCHEMICALS, NUTRACEUTICALS, CAROTENOIDS,
ANTIOXIDANTS, OXIDATIVE STRESS, CANCER, CORONARY HEART DISEASE (CHD), INSULIN,
PROANTHOCYANIDINS, FOSHU.
Anthocyanins
See ANTHOCYANIDINS.
Anti-Idiotype Antibodies
See ANTI-IDIOTYPES.
Anti-Idiotypes
Antibodies to antibodies. In other words, if a human antibody is
injected into rabbits, the rabbit immune systems will recognize the human
antibodies as foreign (regardless of the fact that they are antibodies) and
produce antibodies against them. To the rabbit, the foreign antibodies
represent just another invader or nonself to be targeted and destroyed. Anti-idiotypes
mimic antigens in that they are shaped to fit into the antibody’s binding site
(in lock-and-key fashion). As such, anti-idiotypes can be used to create
vaccines that stimulate production of antibodies to the antigen (that the
antiidiotype mimics). This confers disease resistance (to the pathogen
associated with that antigen) without the risk that a vaccine using attenuated
pathogens entails (i.e., that the pathogen “revives” to cause the disease). See
also ANTIBODY, MONOCLONAL ANTIBODIES (MAb), ANTIGEN, IDIOTYPE, PATHOGEN,
ATTENUATED (PATHOGENS).
Anti-Interferon
An antibody to interferon. Used for the purification of
interferons. See also ANTIBODY, INTERFERONS, AFFINITY CHROMATOGRAPHY.
Anti-Oncogenes
See ONCOGENES, ANTISENSE (DNA SEQUENCE).
Antiangiogenesis
Refers to impact of any compound that prevents angiogenesis (i.e.,
formation/development of new blood vessels). Because angiogenesis is required
for malignant tumors to grow and/or metastasize (spread), antiangiogenesis was
proposed by Judah Folkman in 1970 as a means to combat cancer. Because
angiogenesis is required for embryonic development, antiangiogenic drugs
inhibit proper development/growth of infants in the womb. Fumagillin, ovalicin,
and Thalidomide have been found to possess antiangiogenic properties. Also, the
human proteins angiostatin and endostatin. See also ANGIOGENESIS, ANGIOGENIC
GROWTH FACTORS, TUMOR, CANCER, ANGIOSTATIN, ENDOSTATIN, GENISTEIN.
Antibiosis
Refers to the processes by which one organism produces a substance
that is toxic or repellent to another organism (e.g., a parasite) that is
attacking the first organism. For example, certain varieties of corn/maize (Zea mays L.) naturally produce
chemical substances in their roots that are toxic to the corn rootworm. See
also ANTIBIOTIC, BACILLUS THURINGIENSIS (B.t.), CORN, CORN ROOTWORM.
Antibiotic
Coined by Selman Waksman during the 1940s, this term refers to
organic compounds that are naturally formed and secreted by various species of
microorganisms and/or plants. It has a defensive function and is often toxic to
other species (e.g., penicillin, originally produced by bread mold, is toxic to
numerous human pathogens). Antibiotics generally act by inhibiting protein
synthesis, DNA replication, synthesis of cell wall (cytoplasmic membrane)
constituents, inhibition of required cell (e.g., bacteria) metabolic processes,
and nucleic acid (DNA and RNA) biosynthesis, hence killing the (targeted
bacteria) cells involved. Inorganic (e.g., certain metals) molecules may also have
antibiotic properties. See also PATHOGEN, MICROORGANISM, PROTEIN, NUCLEIC
ACIDS, PENICILLIN G (benzylpenicillin), SYMBIOTIC, GRAM STAIN, GRAMNEGATIVE, ALLELOPATHY,
BACTERIA, GRAM-POSITIVE, CELL, ANTIBIOSIS, AUREOFACIN, PHOTORHABDUS LUMINESCENS,
BETA-LACTAM ANTIBIOTICS, METABOLISM, DEOXYRIBONUCLEIC ACID (DNA), PLASMA
MEMBRANE, RIBONUCLEIC ACID (RNA).
Antibiotic Resistance
A property of a cell (e.g.. pathogenic bacteria) that enables it
to avoid the effect of an antibiotic that had formerly killed or inhibited that
cell. Ways this can occur include: changing the structure of the cell wall
(plasma membrane); synthesis (manufacture) of enzymes to inactivate the antibiotic
(e.g., penicillinases, which inactivate penicillin); synthesis of enzymes to
prevent antibiotic entering cell; and active removal of the antibiotic from the
cell. For example, the membrane transporter protein molecules known as ABC
transporters are sometimes able to help pathogenic bacteria resist certain
antibiotics by transporting out the antibiotic before it can kill the bacteria.
The ABC transporter is a V-shaped molecule embedded in the (bacteria) cell’s
plasma membrane, with the open end of the “V” pointed toward the interior of
the cell. When molecules of certain antibiotics (inside the cell) contact the
ABC transporter molecule, the two “arms” of the ABC transporter close around
the antibiotic molecule, the ABC transporter flips over, and thereby sends the antibiotic
molecule out through the exterior of the cell’s plasma membrane, replacing some
critical cell metabolic processes, with (new) metabolic processes that bypass
the antibiotic’s (former) effect. See also CELL, PATHOGEN, PATHOGENIC,
BACTERIA, ANTIBIOTIC, PLASMA MEMBRANE, ENZYME, PENICILLINASES, METABOLISM, ABC
TRANSPORTERS, MYCOBACTERIUM TUBERCULOSIS.
Antibody
Also called immunoglobulin, Ig. A large defense protein that
consists of two classes of polypeptide chains, light (L) chains and heavy (H)
chains. A single antibody molecule consists of two identical copies of the L
chain and two of the H chain. They are synthesized (made) by the immune system
(B lymphocytes) of the organism. The antibody is composed of four proteins linked
together to form a Y-shaped bundle of proteins (looks somewhat like a slingshot
or two hockey sticks taped together at the handles). The amino acid sequence
that makes up the stem (heavy chains) of the Y (i.e., the handles of the taped
together hockey sticks) is similar for all antibodies. The stem is known as the
Fc region of the antibody, and it does not bind to antigens, but does have
other regulatory functions. The two arms of the Y are each made up of two
side-by-side proteins called light chains and heavy chains (proteins are chains
of amino acids), with identical antigen-binding (ab) sites on the tips of each
“arm.” The antibody is thus bivalent in that it has two binding sites for
antigen. Taken together, the two arms of the Y are known as the Fab portions of
the antibody molecule. The Fab portions can be cleaved from the antibody
molecule with papain (an enzyme that is also used as a meat tenderizer) or the
Fab portions can be produced by genetically engineered Escherichia coli (E. coli) bacteria. When a
foreign molecule (e.g., a bacterium, virus, etc.) enters the body, B
lymphocytes are stimulated into becoming rapidly dividing blast cells, which mature
into antibody-producing plasma cells. The plasma cells are triggered by the
foreign molecule’s epitope(s) [i.e., group or groups of specific atoms (also
known as a hapten), that are recognized to be foreign by the body’s immune
system] into producing antibody molecules possessing antigen-binding (ab) sites
(also called combining sites or determinants). These fit into the foreign
molecule’s epitope. Thus, via the tips of its arms, the antibody molecule binds
specifically to the foreign entity (antigen) that has entered the body. By this
process it inactivates that foreign molecule or marks it for eventual destruction
by other immune system cells. System marking of the foreign molecule (e.g., pathogen
or toxin) for destruction is accomplished by the fact that the stem of the Y
(i.e., the Fc) fragment hangs free from the combined antibody-antigen clump,
thereby providing a receptor for phagocytes, which roam throughout the body
ingesting and subsequently destroying such “marked” foreign molecules. Research
published during 2001 indicates that antibodies may also kill some pathogens
themselves by catalyzing the formation of hydrogen peroxide from oxygen free
radicals (singlet oxygen) and water. Hydrogen peroxide is highly reactive, and could
potentially kill pathogens when generated by an (attached) antibody. There are five
classes of immunoglobulin: IgG, IgM, IgD, IgA, and IgE. See also HUMORAL
IMMUNITY,
IMMUNOGLOBULIN, PROTEIN, POLYPEPTIDE (PROTEIN), AMINO ACID, B
LYMPHOCYTES, BLAST CELL, ANTIGEN, HAPTEN, EPITOPE, COMBINING SITE, DOMAIN (OF A
PROTEIN), SEQUENCE (OF A PROTEIN MOLECULE), ESCHERICHIA COLIFORM (E. COL I ), PATHOGEN, TOXIN,
PHAGOCYTE, MICROPHAGE, MONOCYTES, T CELLS, POLYMORPHONUCLEAR LEUKOCYTES (PMN),
CELLULAR IMMUNE RESPONSE, POLYMORPHONUCLEAR GRANULOCYTES, GENETIC ENGINEERING,
“MAGIC BULLET”, ENGINEERED ANTIBODIES, RECEPTORS, OXYGEN FREE RADICALS.
Antibody Affinity Chromatography
A type of chromatography in which antibodies are immobilized onto
the column material. The antibodies bind to their target molecules while the
other components in the solution are not retained. In this way a separation
(purification) is achieved. See also ANTIBODY, CHROMATOGRAPHY, AFFINITY
CHROMATOGRAPHY.
Antibody-Mediated Immune Response
See HUMORAL IMMUNE RESPONSE.
Anticoding Strand
Refers to the single strand of DNA (double helix) that
is transcribed. Sometimes called the antisense strand or the template strand.
See also DEOXYRIBONUCLEIC ACID (DNA), TRANSCRIPTION, ANTISENSE (DNA SEQUENCE).
Anticodon A specific sequence of three
nucleotides in a transfer RNA (tRNA), complementary to a codon (also three
nucleotides) for an amino acid in a messenger RNA. See also CODON, TRANSFER RNA
(tRNA), AMINO ACID, MESSENGER RNA (mRNA), NUCLEOTIDE.
Antigen
Also called an immunogen. Any large molecule or small
organism whose entry into the body provokes synthesis of an antibody or immunoglobulin
(i.e., an immune system response). See also HAPTEN, ANTIBODY, EPITOPE, CELLULAR
IMMUNE RESPONSE, HUMORAL IMMUNITY.
Antigenic Determinant
See HAPTEN, EPITOPE, SUPERANTIGENS.
Antihemophilic Factor VIII
Also known as Factor VIII or Antihemophilic Globulin (AHG).
See also FACTOR VIII.
Antihemophilic Globulin
Also known as Factor VIII or Antihemophilic Factor
VIII. See also FACTOR VIII.
Antioxidants
Compounds (e.g., phytochemicals) that act to prevent
lipids from oxidizing (to plaque) or breaking down (e.g., to carcinogenic compounds),
or that act to capture and halt singlet oxygen (O-) free radicals; which can
damage DNA in cells (causing mutations). Since oxidation of lipids in the blood
is the intitial step in atherosclerosis, consumption of large amounts of
certain antioxidants (e.g., flavonoids) may prevent atherosclerosis. Because
oxidation reactions within the body often lead to formation of tissue-damaging
free radicals (molecules containing an “extra” electron), consumption of
antioxidants can help to prevent such tissue damage. Evidence indicates that tissue
damage from free radicals may play a role in causing some arthritis, coronary
heart disease, diabetes, and cancers. Synthetic analogues have also been
manufactured (e.g., synthetic vitamins, etc.) which perform a similar
antioxidant function to naturally occurring antioxidant phytochemicals. See also
OXIDATIVE STRESS, PHYTOCHEMICALS, LIPIDS, CARCINOGEN, CANCER, ANALOGUES,
OXIDATION, CORONARY HEART DISEASE, INSULIN,
LYCOPENE, MUTAGEN, MUTATION, FLAVONOIDS, ISOFLAVONES,
ATHEROSCLEROSIS, ASTAXANTHIN, HUMAN SUPEROXIDE DISMUTASE (hSOD), PEG-SOD (POLYETHYLENE
GLYCOL SUPEROXIDE DISMUTASE), PLAQUE, PHYTATE, POLYPHENOLS, BETA CAROTENE,
VITAMIN E, POLYUNSATURATED FATTY ACIDS (PUFA), CONJUGATED LINOLEIC ACID (CLA).
Antiparallel
Describes molecules that are parallel but point in
opposite directions. The strands of the DNA double helix are antiparallel. See
also DOUBLE HELIX.
Antisense (DNA sequence)
A strand of DNA that produces a messenger RNA (mRNA) molecule
which (when reversed end-forend) has the same sequence as (is complementary to)
the unwanted (“bad”) messenger RNA. The SENSE (forward) and ANTISENSE (backward)
mRNA strands hybridize (tightly bond to each other), which prevents the bonded
pair from leaving the cell’s nucleus, so that bonded pair is rapidly degraded
(destroyed) by nuclei within the cell nucleus. In genetic targeting (to block “bad”
genes), antisense molecules are used to bind to a “bad” gene’s (an oncogene)
messenger RNA (mRNA), thus canceling the (cancer-causing) message of the gene
and preventing cells from following its (tumor growth) instructions. Another
example would be the use of antisense DNA to block the gene that codes for
production of polygalacturonase (an enzyme that causes ripe fruit to (soften).
Physically, antisense is accomplished by removing a given gene from an
organism’s genome, reversing it (end-for-end), and reinserting it back into the
organism’s genome. See also DEOXYRIBONUCLEIC ACID (DNA), CODING SEQUENCE, GENE,
GENOME, COMPLEMENTARY DNA (c-DNA), MESSENGER RNA (mRNA), GENETIC TARGETING, CANCER,
POLYGALACTURONASE (PG), ONCOGENES, SENSE, COSUPPRESSION, GENE SILENCING, HYBRIDIZATION
(MOLECULAR GENETICS), NUCLEASE, ANTICODING STRAND.
Antisense RNA
See ANTISENSE (DNA SEQUENCE).
Antithrombogenous Polymers
Synthetic polymers (i.e., plastics) used to make
medical devices that will be in contact with a patient’s A blood
(e.g., catheters), but will not initiate the coagulation process as synthetic polymers
usually do. The natural anticoagulant heparin is incorporated into the polymer
and is gradually released into the bloodstream by the polymer, thus preventing
blood coagulation on the surface of the polymer. See also POLYMER, THROMBOSIS.
Antitoxin
See POLYCLONAL ANTIBODIES, DIPHTHERIA ANTITOXIN.
AP
Atrial peptide. See also ATRIAL PEPTIDES.
APHIS
The Animal and Plant Health Inspection Service is the
agency of the U.S. Department of Agriculture responsible for regulating the
field (outdoor) testing of genetically engineered plants and certain microorganisms.
See also COORDINATED FRAMEWORK FOR REGULATION OF BIOTECHNOLOGY, MICROORGANISM,
GENETIC ENGINEERING.
Aplastic Anemia
An autoimmune disease of the bone marrow. See also
AUTOIMMUNE DISEASE.
APO B-100
See LOW-DENSITY LIPOPROTEINS (LDLP), APOLIPOPROTEINS,
VERY LOW-DENSITY LIPOPROTEINS (VLDL).
APO-1/Fas
See CD95 PROTEIN.
Apoenzyme
The protein portion of a holoenzyme. Many (but not
all) enzymes are composed of functional “pieces” (i.e., a protein piece (chain)
and another piece that is an organic and/or inorganic molecule). The other
piece is known as a cofactor, and it may be removed from the enzyme under
certain conditions, after which the resulting inactive enzyme is known as an
apoenzyme. The inactive apoenzyme becomes functionally active again if it is
allowed to recombine with its cofactor. See also COFACTOR, ENZYME, HOLOENZYME.
Apolipoprotein B
See LOW-DENSITY LIPOPROTEINS (LDLP), APOLIPOPROTEINS,
VERY LOW-DENSITY LIPOPROTEINS (VLDL).
Apolipoproteins
The protein portion of lipoproteins (i.e., after the
lipid portion is removed from those molecules). See also LOW-DENSITY
LIPOPROTEINS (LDLP), PROTEIN, LIPIDS, VERY LOW-DENSITY LIPOPROTEINS (VLDL).
Apomixis
A method of reproduction used by scientists to
propagate (hybrid) plants without having to utilize sexual fertilization. By combining
apomixis with tissue culture technology, Cai Detian, Ma Piugfu, and Yao Jialin
were able to propagate rice varieties in 1994. In 1998, Dimitri Petrov, Phillip
Sims, and Chester Deald were able to cause apomixis in corn (maize). By
“fixing” hybrid dominance, the need for (sexual) breeding is eliminated and the
hybrid vigor is passed down via the seed from generation to generation. See
also ASEXUAL, GERM CELL, HYBRID VIGOR, TISSUE CULTURE, HYBRIDIZATION (PLANT GENETICS),
CORN, F1 HYBRIDS.
Apoptosis
Also called “programmed cell death,” it is a series of
programmed steps that cause a cell to die by “self digestion” without rupturing
and releasing intracellular contents (e.g., nucleus, chromosomes, refractile bodies,
etc.) into the local (surrounding tissue) environment. Manifestations of cell apoptosis
include shrinking of the cell’s cytoplasm and chromatin condensation. If the
normal cell apoptosis is prevented (e.g., by an enzyme that is present due to
disease) in the body, cells can grow uncontrollably (i.e., causing cancer). For
example, people with chronic myelogenous leukemia (CML, also known as chronic
myeloid leukemia) typically have 10–25 times as many white blood cells as
normal. See also CELL, CD95 PROTEIN, SIGNAL TRANSDUCTION, SIGNALING, REFRACTILE
BODIES (RB), NUCLEUS, CHROMOSOMES, CHROMATIN, CYTOPLASM, FUSARIUM, p53 GENE,
TUBULIN, CANCER, SELECTIVE APOPTOTIC ANTI-NEOPLASTIC DRUG (SAAND),
HYPERSENSITIVE RESPONSE, SIGNAL TRANSDUCTION, SIGNAL TRANSDUCERS AND ACTIVATORS
OF TRANSCRIPTION (STATs), GENE EXPRESSION CASCADE, ENZYME, WHITE BLOOD CELLS,
PHILADELPHIA CHROMOSOME, GLEEVEC™.
Approvable Letter (from the FDA)
One of the final steps in the U.S. Food and Drug
Administration’s (FDA) review process for new pharmaceuticals. The letter
precedes final FDA clearance for marketing of the new compound. See also FOOD
AND DRUG ADMINISTRATION (FDA), IND, IND EXEMPTION.
Aptamers
Oligonucleotide molecules that bind (stick to) other,
specific molecules (e.g., proteins). Aptamer is from the Latin aptus, to fit.
In 1992, Louis Bock and John Toole isolated aptamers that bind and inhibit the blood-coagulation
enzyme thrombin. Since thrombin is crucial to the formation of blood A clots
(coagulation), such aptamers may someday be useful for anticoagulant therapy (e.g.,
to prevent blood clots following surgery or heart attacks). See also ENZYME, OLIGONUCLEOTIDE,
PROTEIN, INHIBITION, THROMBIN, THROMBUS, THROMBOSIS.
Arabidopsis thaliana
A small weed plant (Cruciferae) possessing 70,000
kilobase pairs in its genome, with very little repetitive DNA. This makes it an
ideal model for studying plant genetics. At least two genetic maps have been
created for Arabidopsis thaliana (one using yeast artificial
chromosomes). Because of this, a large base of knowledge about it has been
accumulated by the scientific community. A. thaliana was first
genetically engineered in 1986. In 1994, researchers succeeded in transferring
genes for polyhydroxylbutylate (“biodegradable plastic”) production into A.
thaliana. Because production of polyhydroxylbutylate (PHB) requires
simultaneous expression of three genes (the PHB production process is
“polygenic”) — yet researchers have only been able to insert a maximum of two
genes — they have to insert two genes into one plant and one gene into a second
plant, then finally get the (total) three genes into (offspring) plants via
traditional breeding. During 2001, Eduardo Blumwald and Hong-Xia Zhang inserted
a salt-tolerance gene from A. thaliana into a tomato (Lycopersicon
esculentum), and thereby made that tomato plant resistant to salt in
concentrations up to 200 mM (far higher than it could previously survive). See also
BRASSICA, GENE, EXPRESS, BASE PAIR (bp), KILOBASE PAIRS (Kbp), GENOME, GENETIC
CODE, GENETIC MAP, GENETICS, TRAIT, POLYGENIC, DEOXYRIBONUCLEIC ACID (DNA),
POLYHYDROXYLBUTYLATE (PHB), YEAST ARTIFICIAL CHROMOSOMES (YAC), MODEL ORGANISM,
TOMATO, SALT TOLERANCE.
Arachidonic Acid (AA)
One of the omega-6 (n-6) highly unsaturated fatty
acids (HUFA), AA is synthesized (manufactured) by the human body from linoleic
acid (e.g., obtained by consuming soybean oil). AA is present in human breast
milk, and research indicates that it plays an important role in the mental
development of infants. Arachidonic acid is a crucial precursor for
prostaglandins and other eicosanoids. The COX-1 enzyme converts arachidonic
acid to constitutive prostaglandins and the COX-2 enzyme converts arachidonic
acid to inducible prostaglandins. See also CYCLOOXYGENASE, POLYUNSATURATED
FATTY ACIDS (PUFA), N-6 FATTY ACIDS, FATTY ACIDS, UNSATURATED FATTY ACIDS,
LINOLEIC ACID, SOYBEAN OIL, CONSTITUTIVE ENZYMES, INDUCIBLE ENZYMES,
LEUKOTRIENES, ESSENTIAL FATTY ACIDS, EICOSANOIDS.
Archaea
Single-celled life forms that can live at extreme
ocean depths (high pressure) and in the absence of oxygen. Enzymes robust (sturdy)
enough for industrial process utilization have been isolated by scientists from
some strains of Archaea. Other Archaea strains
are sometimes present in the rumen (“first stomach”) of cattle and sheep. Those
Archaea produce methane gas by breaking down some of the feed
consumed by the cattle and sheep. See also ENZYME, EXTREMOZYMES, CELL,
ANAEROBE, ANAEROBIC, STRAIN.
Arginine (arg)
An amino acid, commonly abbreviated arg. In dry, bulk
form arginine is colorless, crystalline, and water soluble. It is an essential
amino acid of the α-ketoglutaric acid family. See also AMINO ACID,
ESSENTIAL AMINO ACIDS, NITRIC OXIDE SYNTHASE.
ARM
Acronym for antibiotic resistance marker. See also
MARKER (GENETIC MARKER). ARMD Acronym for Age-Related Macular Degeneration.
See also LUTEIN.
ARMG
Acronym for Antibiotic Resistance Marker Gene. See
also ANTIBIOTIC, ANTIBIOTIC RESISTANCE, GENE, MARKER (GENETIC MARKER), RECOMBINASE.
Armyworm
Caterpillars (pupae) of the Lepidopteran insect Pseudaletia
unipuncta family; most of which are harmful to crops (e.g., wheat,
corn/maize, etc.) grown by humans. Armyworms are susceptible to some of the “cry”
proteins (e.g., they are killed if they eat plants genetically engineered to contain
Cry1A(b), Cry9C, or Cry1F proteins). Armyworms are preyed upon by some species of
ground beetles, sphecid wasps, toads, birds, etc. See also PROTEIN, VOLICITIN,
CRY PROTEINS, CRY1A(b) PROTEIN, CRY1F PROTEIN, CRY9C PROTEIN, CORN, WHEAT.
AroA
Refers to the transgene (cassette) which was initially
isolated/extracted from the genome of the Agrobacterium bacteria species (strain
CP4) and inserted via genetic engineering techniques into a crop plant (e.g.,
soybean, Glycine max L.) in order to make that (soybean) plant tolerant to
glyphosate- based herbicides (and also sulfosatebased herbicides). See also
GENE, TRANSGENE, CASSETTE, GENOME, AGROBACTERIUM TUMEFACIENS, EPSP SYNTHASE,
mEPSPS, CP4 EPSPS, SOYBEAN, HERBICIDE-TOLERANT CROP, GENETIC ENGINEERING,
SOYBEAN PLANT, GLYPHOSATE, SULFOSATE.
ARS
See ARS ELEMENT.
ARS Element
A sequence of DNA that will support autonomous
replication (sequence, ARS). See also DEOXYRIBONUCLEIC ACID (DNA), SEQUENCE (OF
A DNA MOLECULE).
Arteriosclerosis
A group of diseases (including atherosclerosis) which
is characterized by a decrease in elasticity (stretchiness) and a thickening of
the walls of the body’s arteries. See also ATHEROSCLEROSIS, CORONARY HEART
DISEASE (CHD), PLAQUE.
Arthritis
See OSTEOARTHRITIS, AUTOIMMUNE DISEASE.
Ascites
Liquid accumulations in the peritoneal cavity. Used as
an input in one of the methods for producing monoclonal antibodies. See also
MONOCLONAL ANTIBODIES (MAb), PERITONEAL CAVITY/MEMBRANE, ANTIBODY.
Ascorbic Acid
A water-soluble vitamin and antioxidant. See also
VITAMIN, ANTIOXIDANTS.
-ase
The three-letter suffix that is added to a (root) word
to denote an enzyme. For example, the stomachs of reindeer contain lichenase, an
enzyme that enables reindeer to digest lichen that the reindeer consume as a
source of winter food. See also ENZYME, PROTEASE, OXYGENASE, HUMAN PROTEIN
KINASE C, HUMAN SUPEROXIDE DISMUTASE (hSOD), POLYMERASE, ATPase, ATP SYNTHASE,
REGULATORY ENZYME.
Asexual
Denotes fertilization and/or reproduction by in vitro
means. Without sex. See also IN VITRO,
APOMIXIS, GERM CELL.
Asian Corn Borer
Also known by its Latin name, Ostrinia
furnacalis is an insect (originally from Asia) whose larvae (caterpillars) eat
and bore into the corn/maize (Zea Mays L.)
plant. In doing so, they can act as vectors (carriers) of the fungi known as Aspergillus
flavus (a source of aflatoxin), Fusarium moniliforme (a source
of fumonisin), or Aspergillus parasiticus (a source
of aflatoxin). See also EUROPEAN CORN BORER (ECB), CORN, FUNGUS, AFLATOXIN,
FUSARIUM, FUSARIUM MONILIFORME.
Asparagine (asp)
An amino acid, commonly abbreviated asp. In dry, bulk
form asparagines appears as a white, crystalline solid. It is found in high
amounts in many plants. See also AMINO ACID.
Aspartic Acid
A dicarboxylic amino acid found in plants and animals,
especially in molasses from young sugarcane and sugar beets. See also AMINO
ACID.
Aspergillus flavus
See AFLATOXIN, PEROXIDASE, BETA CAROTENE.
Assay
A test (specific technique) that measures a response
to a test substance or the efficacy (effectiveness) of the test substance. See
also IMMUNOASSAY, BIOASSAY, LUMINESCENT ASSAY, HYBRIDIZATION SURFACES.
Assimilation
The formation of self cellular material from small
molecules derived from food. See also INSULIN-LIKE GROWTH FACTOR-1 (IGF-1),
RIBOSOMES, MESSENGER RNA (mRNA).
Association of Biotechnology Companies (ABC)
An American trade association of companies
involved in biotechnology and services
to biotechnology companies (e.g., accounting,
law, etc.). Formed in 1984, the ABC
tended to consist of the smaller firms involved
in biotechnology (and service firms that
worked for all biotechnology companies). In 1993,
the ABC was merged with the Industrial Biotechnology Association (IBA) to
form the Biotechnology Industry Organization
(BIO). See also INDUSTRIAL BIOTECHNOLOGY ASSOCIATION
(IBA), BIOTECHNOLOGY INDUSTRY ORGANIZATION (BIO), BIOTECHNOLOGY.
Astaxanthin
A carotenoid pigment responsible for the
characteristic pink coloring of salmon, trout, and shrimp. It is produced by the
microorganisms in the natural (wild) diets of those aquatic animals. Research
has shown that astaxanthin (an antioxidant) helps boost the immune systems of
humans that consume it. Research has also shown that astaxanthin helps to
reduce oral cancer A in rats and inhibit breast cancer in mice. See also
CAROTENOIDS, ANTIOXIDANTS, OXIDATIVE STRESS.
AT-III
A human blood factor that promotes clotting. A
deficiency of AT-III can be inherited or can result from certain surgical
procedures, certain illnesses, and sometimes use of certain oral
contraceptives. See also FACTOR VIII.
ATCC
See AMERICAN TYPE CULTURE COLLECTION (ATCC), TYPE
SPECIMEN, ACCESSION.
Atherosclerosis
A form of arteriosclerosis characterized by deposition
and buildup of fatty deposits (plaque) on the internal walls of the body’s
arteries, in addition to the decreased elasticity of artery walls that
characterizes all forms of arteriosclerosis. When a piece of plaque breaks off,
a blood clot generally forms, and that clot often blocks blood flow through the
artery, causing a heart attack or stroke. See also ARTERIOSCLEROSIS, CORONARY HEART
DISEASE (CHD), CHOLESTEROL, THROMBOSIS, THROMBUS, FLAVONOIDS, OXIDATIVE STRESS,
ANTIOXIDANTS, PLAQUE.
Atomic Weight
The total mass of an atom equal to the sum of the
isotope’s number of protons and neutrons (in the atom’s nucleus). The atomic
weights of the earth’s elements are based on the assignment of exactly 12.000 as
the atomic weight of the carbon-12 isotope (variation of atom). The atomic
(weight) theory was established as a framework in 1869 by Meyer and Mendeléev,
but standard precise values were not adopted internationally until an
international commission on atomic weights was formed in 1899 in response to an
initiative by the German Chemical Society. An element’s atomic weight does not come
out to a whole number (with the exception of carbon), because of the existence
of isotopes which differ slightly with respect to the number of neutrons each
contains. See also MOLECULAR WEIGHT, ISOTOPE.
ATP
See ADENOSINE TRIPHOSPHATE (ATP).
ATP Synthase
An enzyme complex that forms ATP from ADP and phosphate
during oxidative phosphorylation in the inner mitochondrial membrane (in
animals), in chloroplasts (in plants), and in cell membranes (in bacteria).
This is an energy-producing reaction in that ATP is a high-energy compound used
by cells to maintain their living condition. ATP synthase is also present on
the surface of endothelial cells (lining of blood vessels) where it helps to
build new blood vessels (e.g., to replace tissue damaged by injury or disease).
Under certain circumstances, this also creates new blood vessels that provide
blood supply to tumors. When separated from the cell’s membrane, ATP synthase
hydrolyzes (breaks down) ATP via a chemical process in which one subunit (designated
g) of ATP synthase rotates within the other (hollow) part of ATP synthase. See
also ENZYME, CHLOROPLASTS, ADENOSINE TRIPHOSPHATE (ATP), HYDROLYSIS, ADENOSINE
DIPHOSPHATE (ADP), MITOCHONDRIA, TUMOR, ENDOTHELIAL CELLS, ANGIOSTATIN.
ATP Synthetase
See ATP SYNTHASE.
ATPase
Adenosine triphosphatase, an enzyme that hydrolyzes
(clips the bond between two phosphates in) ATP to yield ADP, phosphate, and
energy. The reaction is usually coupled to an energy-requiring process. ATP is hydrolyzed
in the act of shivering and the energy produced is converted into heat to increase
body temperature. This type of heat production involves what is known as a
futile cycle because the energy is converted to (and wasted as) heat rather
than used in motion, etc. See also ATP SYNTHASE, ENZYME, ADENOSINE TRIPHOSPHATE
(ATP), ADENOSINE DIPHOSPHATE (ADP), FUTILE CYCLE, HYDROLYSIS, HYDROLYZE.
Atrial Natriuretic Factor
An atrial peptide hormone that may regulate blood
pressure and electrolyte balance within the body. An example is a peptide
hormone. See also HORMONE, ATRIAL PEPTIDES, PEPTIDE.
Atrial Peptides
Endocrine components (proteins) that act to regulate
blood pressure, as well as water and electrolyte homeostasis within the body.
Atrial peptides are made by the heart in response to elevated blood pressure levels,
and they stimulate the kidneys to excrete water and sodium into the urine, thus
lowering blood pressure. They also slow the heartbeat. An example is a peptide
hormone. See also ENDOCRINE HORMONES, HOMEOSTASIS, ELECTROLYTE.
Attenuated (pathogens)
Inactivated, rendered harmless (e.g., killed viruses
used to make A a vaccine). Some of the ways in which viruses and
other pathogens may be attenuated are by heat, chemical, or radiation
treatment. See also PATHOGEN.
Attenuation (of RNA)
Premature termination of an elongating RNA chain. See
also RIBONUCLEIC ACID (RNA).
Aureofacin
An antifungal antibiotic produced by a strain of Streptomyces
aureofaciens. At least one company has incorporated the gene for this
antibiotic (which acts against wheat take-all disease) into a Pseudomonas
fluorescens used to confer resistance to wheat takeall disease by allowing
the bacteria to colonize the wheat’s roots. In this way the plant obtains the
benefits of the antibiotic because the bacteria become part of the plant. See also
PSEUDOMONAS FLUORESCENS, ENDOPHYTE, ANTIBIOTIC, BACILLUS
THURINGIENSIS (B.t.).
Autogenous Control
The action of a gene product (a molecule) that either
inhibits (negative autogenous control) or activates (positive autogenous
control) expression of the gene that codes for it (Greek auto, self). The
presence of the product either causes or stops its own production. See also
GENE, EXPRESS.
Autoimmune Disease
A disease in which the body produces an immunogenic
(immune system) response to some constituent of its own tissue. In other words,
the immune system loses its ability to recognize some tissue or system within
the body as “self” and targets and attacks it as if it were foreign. Autoimmune
diseases can be classified into those in which one organ is predominantly
affected
(e.g., hemolytic anemia and chronic thyroiditis), and
those in which the autoimmune disease process is diffused through many tissues (e.g.,
multiple sclerosis, systemic lupus erythematosus, and rheumatoid arthritis). For
example, multiple sclerosis is thought to be caused by T cells attacking
acetylcholine receptors in the sheaths (myelin) that surround the nerve fibers
of the brain and spinal cord. This eventually results in loss of coordination,
weakness, and blurred vision. Arthritis is caused by immune system cells attacking
joint tissues. Certain bacterial infections (e.g., Lyme disease, Salmonella, etc.)
are followed by arthritis in approximately 10% of cases. The antigen (on
surface of those bacteria) targeted by the human immune system is similar (in
its molecular shape) to a protein located on the surface of cells in human
joint tissue(s). See also THYMUS, SUPERANTIGENS, T CELLS, TUMOR NECROSIS FACTOR
(TNF), MULTIPLE SCLEROSIS, MYOELECTRIC SIGNALS, ACETYLCHOLINE, LUPUS,
INSULINDEPENDENT DIABETES MELLITIS (IDDM), DIABETES, ANTIGEN, BACTERIA, SALMONELLA
TYPHIMURIUM, PROTEIN, CELL.
Autonomous Replicating Segment
See ARS ELEMENT.
Autonomous Replicating Sequence
See ARS ELEMENT.
Autoradiography
A technique to detect radioactively labeled molecules
by creating an image on photographic film. The slab of gel or other material in
which the molecules are held (suspended) is placed on top of a piece of
photographic film. The two are then securely fastened together such that
movement is eliminated and the film is exposed for a period of time. The
exposed (to the radiation) film is subsequently developed and the radioactive
area is seen as a dark (black) area. Among other uses, autoradiography has been
used to track the spread of (radioactively labeled) viruses in a living plant.
After treatment (the radioactive labeling process), the whole plant (in a slab)
is placed on top of a piece of photographic film. When the film is subsequently
developed, the picture seen is of a plant, with darker areas indicating regions
of greater virus concentration. See also LABEL (RADIOACTIVE), VIRUS.
Autosomes
All chromosomes except the sex chromosomes. A diploid
cell has two copies of each autosome.
Autotroph
An organism that can live on very simple carbon and
nitrogen sources, such as carbon dioxide and ammonia. See also HETEROTROPH.
Auxins
From the Greek auxein, to
increase, this term refers to a family of chemical compounds that regulate
plant growth (e.g., stimulate cell enlargement, cell division, initate roots/growth,
flowering, etc.). See also CELL.
Auxotroph
Auxotrophic mutant. A mutant defective in the
synthesis of a given biomolecule. The biomolecule must be supplied to the organism if normal
growth is to be achieved. See also MUTATION,
GENE, GENE DELIVERY (GENE THERAPY), ESSENTIAL
FATTY ACIDS.
Avidin
A protein naturally present in egg white, oilseed protein (e.g.,
soybean meal), and grain (e.g., corn/maize), it is 70 kilodaltons in mass
(weight) and has a high affinity for biotin (i.e., it “sticks” tightly to the
biotin molecule). Since grain-eating insects require biotin (a B-complex
vitamin) to live, adding extra avidin to grain (e.g., by inserting a gene to
cause overproduction of avidin in the grain kernels) may be a way to protect
grain from insects (e.g., weevils in stored corn/maize). See also PROTEIN, SOY
PROTEIN, CORN, KILODALTON (KD), BIOTIN, WEEVILS, VITAMIN.
Avidity (of an antibody)
The “tightness of fit” between a given antibody’s combining site and
the antigenic determinant with which it combines. The firmness of the combination
of antigen with antibody. See also ANTIGENIC DETERMINANT, ANTIBODY, ANTIGEN,
COMBINING SITE, POLYCLONAL RESPONSE, CATALYTIC ANTIBODY.
Azadirachtin
The pharmacophore (active ingredient) in secretions of the
tropical neem tree, which resists insect depradations. See also PHARMACOPHORE,
NEEM TREE.
Azurophil-Derived Bactericidal Factor (ADBF)
Potent antimicrobial protein produced by neutrophils (a
type of white blood cell). See also LEUKOCYTES.
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