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 glypho- sate-based herbicides (and also sulfosatebased herbicides). See also GENE, TRANSGENE,

CASSETTE, GENOME, AGROBACTERIUM TUMEFA-

CIENS, EPSP SYNTHASE, mEPSPS, CP4 EPSPS, SOY-

BEAN, 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

(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 arter-

ies. 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), PERI-

TONEAL 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

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

in rats and inhibit breast cancer in mice. See

Aalso 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 syn-

thase. 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, ADENOS-

INE TRIPHOSPHATE (ATP), ADENOSINE DIPHOS-

PHATE (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 HOR-

MONE, 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 hor-

mone. See also ENDOCRINE HORMONES, HOMEOSTASIS, ELECTROLYTE.

Attenuated (pathogens) Inactivated, rendered harmless (e.g., killed viruses used to make

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 RIBO-

NUCLEIC 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

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.

ASee 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.