and animals, including humans. They present a philosophical problem to those who would speak of living and nonliving systems because in and of itself a virus is not “alive” as we know life, but rather represents “life potential” or “symbiotic life.”

See also VACCINIA, NUCLEOPROTEINS, RETROVIRUSES, TOBACCO MOSAIC VIRUS (TMV), VIRAL

TRANSACTIVATING PROTEIN, GENE DELIVERY,

ADENOVIRUS.

Viscosity A measure of a liquid’s resistance to flow, as expressed in units called poise (P; grams per cm per sec). The degree of “thickness” or “syrupiness” of a liquid.

Vitafoods See NUTRACEUTICALS.

Vitamers See VITAMIN.

Vitamin The modern term descended from the original phrase “vital amine” (or “vitamine”), which was coined by Casimir Funk in the early 1900s. Most vitamins are actually “families” of chemically related isomers (i.e., vitamers) which cause same or similar metabolic impact (benefit) in most animals (including humans) that consume those vitamins. Some compounds are vitamins for certain species of animals, but are not for certain other species. In general, a vitamin is an organic compound required in tiny amounts (for the optimal growth, proper biological functioning, and maintenance of health of an organism).

Vitamins are commonly classified into two categories, the fat soluble and the water soluble. Vitamins A, D, E, and K are fat soluble whereas vitamin C (ascorbic acid) and members of the vitamin B complex group are water soluble. In general, the vitamins play catalytic and regulatory roles in the body’s metabolism. Among the watersoluble vitamins, the B vitamins apparently function as coenzymes (nonprotein parts of enzymes). Vitamin C’s coenzyme role, if any, has not been established. Part of the importance of vitamin C to the body may arise from its strong antioxidant action. The functions of the fat-soluble vitamins are less well understood. Some of them, too, may contribute to enzyme activity; and others are essential to the functioning of cellular membranes (on surface of cells).

Some vitamins act as transcription factors. Vitamin A is able to regulate the expression of certain genes in the embryos of mammals, via one of its metabolites; retinoic acid. Those embryo cells contain nuclear receptors (which bring the retinoic acid “signal” from outside into the cell’s nucleus) on their cell membrane surface. The retinoic acid then (via the nuclear receptors) regulates the expression of the genes that cause embryonic cell differentiation into complex body structures, such as legs and arms, of the growing embryo. See also ENZYME, CAT-

ALYST, COENZYME, METABOLISM, METABOLITE,

GENE, EXPRESS, BETA CAROTENE, EMBRYOLOGY,

RETINOIDS, PROTEIN, CELL, RECEPTORS, SIGNALING,

CHOLINE, SIGNALING MOLECULES, SIGNAL TRANS-

DUCTION, NUCLEAR RECEPTORS, LYCOPENE,

LUTEIN, FATS, TRANSCRIPTION FACTORS, SPECIES,

AVIDIN, VITAMIN E, BIOTIN, TOCOPHEROLS,

TOCOTRIENOLS, ANTIOXIDANTS, INOSITOL.

Vitamin E Refers to a group of related, naturally occurring compounds consisting of tocopherol and tocotrienol “families.” It is a fat-soluble vitamin with antioxidant properties (i.e., helps prevent lipids in the body from breaking down). Vitamin E is especially effective at preventing oxidation of low-density lipoproteins (so-called “bad cholesterol”), whose oxidation products (e.g., beta hydroxycholesterol) can be deposited onto the interior walls of blood vessels (e.g., arteries) in the form of plaque — which can result in the disease atherosclerosis — and/or adversely increasing blood platelet aggregation (e.g., clotting). Vitamin E occurs naturally in soybeans, cereal grains, etc., so it can be considered a phytochemical. In 2000, the Institute of Medicine of the U.S. National Academy of Sciences issued a report that called for an increase in the amount of vitamin E consumed each day, to

improve citizens’ health. See also VITAMIN, V

OXIDATIVE STRESS, ANTIOXIDANTS, PHYTOCHEMI-

CALS, OXIDATION, LIPIDS, CHOLESTEROL, LOW-

DENSITY LIPOPROTEINS (LDLP), ATHEROSCLERO-

SIS, PLAQUE, PLATELETS, PHYTOCHEMICALS,

NATIONAL ACADEMY OF SCIENCES (NAS), TOCO-

PHEROLS, TOCOTRIENOLS, SOYBEAN PLANT.

Volicitin A chemical compound produced by Beet Armyworm caterpillars (Spodoptera

exigua) after they have consumed some linoleic acid (in plants they chew on, such as corn/maize). The body cells of Beet Armyworm caterpillars conjugate (i.e., chemically join together) the linoleic acid molecules onto glutamine molecules. The conjugated molecule, consisting of one linoleic acid (molecule) joined to one glutamine (molecule), is known as volicitin. When Beet Armyworm caterpillars subsequently chew on corn/maize plants, some volicitin is inadvertently inserted by

those caterpillars into the tissue of the corn (maize). That volicitin causes the corn (maize) plant to emit certain volatile compounds that attract type(s) of wasps which are natural enemies of the Beet Armyworm; leading them to attack those Beet Armyworm caterpillars (which are feeding on the maize/corn). See also LINOLEIC ACID, CORN,

GLUTAMINE, CELL, OCTADECANOID/JASMONATE

SIGNAL COMPLEX.

Vomitoxin See FUSARIUM, MYCOTOXINS.

Water Activity (Aw) A measure of the “free” unbound water (e.g., in a processed food product) available to sustain the growth of microorganisms (spoilage) and/or to sustain undesired chemical reactions (e.g., “staling” of baked food products). Most bacteria are unable to grow in foods possessing a water activity below 0.90. Most yeasts and molds that cause spoilage cannot grow in foods possessing a water activity below 0.80. Sugars can be added to certain foods in order to increase Aw, as they “bind up” the (formerly) free water present. See also MICROORGANISM,

HYDROPHILIC, BACTERIA, YEAST, PENICILLIUM.

Water Soluble Fiber Food fiber (e.g., oat fiber, barley fiber, soybean fiber) that dissolves in water. It apparently absorbs lowdensity lipoproteins (LDLP) in the intestine, before the fiber passes from the body; plus it inhibits absorption of LDLP by the body’s intestinal walls due to increasing the viscosity of the intestine’s contents. Those two effects thus lower the amount of “bad” cholesterol (i.e., LDLP can lead to hardening/blockage of arteries) in the body and thereby coronary heart disease (CHD). Additional to those two effects, water soluble fiber also absorbs/binds bile acid and causes it to be excreted along with that water soluble fiber. That helps to lower cholesterol levels in the body (bloodstream), because the liver synthesizes (manufactures) more bile acids (to replace those absorbed and removed by the fiber) from cholesterol. Water soluble fiber from oat bran is a polysaccharide known as beta-glucan; composed entirely of glucose (molecular) units. U.S. FDA regulations also include gums, pectins, mucilages, and certain hemicelluloses in the category of water soluble fiber.

0-8493-XXXX-X/01/$0.00+$1.50 © 2001 by CRC Press LLC

Soybean flour/meal is also a source of water soluble fiber.

in a covalent (chemical) bond (between two atoms). Weak interactions include ionic (chemical) bonds, hydrogen bonds, and van der Waals forces. See also VAN DER

WAALS FORCES.

Weevils A term describing a number of insects that consume grains (i.e., grown and used by man). Many of the weevils consume (and proliferate in) stored grains, and stored grain products (e.g., flour). One example of a weevil is the insect known as the pea weevil, which lays its eggs on pea pods or dried peas. When the larvae hatch, they burrow into the pod and eat the peas inside. The insect Theocolax elegans attacks the larvae of maize weevils (Sitophilus granarius, Triboleum castaneum), rice weevils (Sitophilus oryzae), and the lesser grain borer. Thus it could potentially be added to grain storage bins (silos) as part of an Integrated Pest Management (IPM) program. See also INTEGRATED

PEST MANAGEMENT (IPM), BIOTIN, AVIDIN, ALPHA

AMYLASE INHIBITOR-1.

Western Blot Test A test performed on biological samples such as blood (after centrifugation to remove red blood cells from the blood) to detect AIDS antibodies individually. Gel electrophoresis is used to separate the AIDS antigen proteins of killed (known) AIDS viruses. Next the protein bands (resulting from the gel electrophoresis) are exposed to the blood being tested and (AIDS) antibodies stick to specific individual antigens (bands) which are then identified (as being present in the tested blood) via dyes. See also

ACQUIRED IMMUNE DEFICIENCY SYNDROME

(AIDS), ANTIBODY, ANTIGEN, ELECTROPHORESIS,

POLYACRYLAMIDE GEL ELECTROPHORESIS (PAGE),

BASOPHILIC, BUFFY COAT (CELLS).

Western Corn Rootworm Latin name Diabrotica virgifera virgifera LeConte. See also

CORN ROOTWORM.

Wheat Refers to a family of related small grains descended from the natural crossing

Wof three Middle East grasses (Triticum monococcum, Aegilops speltoids, and Triticum tauscii) centuries ago. As a result, wheat’s genome is triploid (i.e., it incorporates three complete sets of deoxyribonucleic acid (DNA)), and contains approximately 17 billion base pairs (bp). Wheat is historically an

annual plant that can attain a height of four feet (1.2 meters), although variations (e.g., shorter) have been bred. The Latin name for traditional (bread) wheat is Triticum aestivum, and for durum (pasta) wheat is Triticum durum desf. Historically, wheat kernels have contained 15% or less protein. Most of the rest of the kernel is composed of starch (amylose and amylopectin). See also GENOME,

DEOXYRIBONUCLEIC ACID (DNA), BASE PAIR (bp),

HYBRIDIZATION (PLANT GENETICS), TRIPLOID,

WHEAT TAKE-ALL DISEASE, WHEAT SCAB, KARNAL

BUNT, WHEAT HEAD BLIGHT, GLUTEN, GLUTENIN,

PROTEIN, STARCH, AMYLOSE, AMYLOPECTIN.

TELETHIA CONTROVERSIA KOON SMUT.

Wheat Head Blight See FUSARIUM. Wheat Scab See FUSARIUM.

Wheat Take-All Disease A fungal disease that attacks wheat (Triticum aestivum) plant roots, and causes dry rot and premature death of the plant. Certain strains of Brassica plants and Pseudomonas bacteria produce compounds that can act as natural antifungal agents against the wheat take-all fungus. See

also FUNGUS, BACTERIA, GENETICALLY ENGI-

NEERED MICROBIAL PESTICIDES (GEMP), BRASSICA,

ALLELOPATHY.

WhiskersTM A trademarked method for inserting DNA (genes) into plants cells, so that those plant cells will then incorporate that new DNA and express the protein(s) coded for by that DNA. Developed by ICI Seeds Inc. (Garst Seed Company) in 1993, Whiskers™ is an alternative to other methods of inserting DNA into plant cells (e.g., the Biolistic® Gene Gun, Agrobacterium tumefaciens, the “Shotgun” Method, etc.); it consists of needle-like crystals (“whiskers”) of silicon carbide. The crystals are placed into a container along with the plant cells, then mixed at high speed, which causes the crystals to pierce the plant cell walls with microscopic “holes” (passages). Then the new DNA (gene) is added, which causes the DNA to flow into the plant cells. The plant cells then incorporate the new gene(s); and thus they have been genetically engineered.

See also BIOLISTIC® GENE GUN, AGROBACTERIUM

TUMEFACIENS, “SHOTGUN” METHOD, GENETIC

E N G I N E E R I N G , G E N E , B I O S E E D S , C O D I N G