O

O Glycosylation S e e G L Y C O S Y L A T I O N ( T O	of such plants. See also SIGNALING MOLECULE,
GLYCOSYLATE).	SIGNALING, EUROPEAN CORN BORER, INTEGRATED
OAB (Office of Agricultural Biotechnology)	PEST MANAGEMENT (IPM), VOLICITIN.
A unit of the U.S. Department of Agriculture	OD See OPTICAL DENSITY.
in charge of a part of the federal regulatory	Odorant Binding Protein A p r o t e i n	t h a t
process for biotechnology (e.g., field tests of	enhances people’s ability to smell odorants
transgenic plants). See also TOXIC SUBSTANCES	in trace quantities much lower than those
CONTROL ACT (TSCA), RECOMBINANT DNA ADVI-	needed to activate olfactory (i.e., smelling)
SORY COMMITTEE (RAC), FOOD AND DRUG ADMIN-	nerves. The protein accomplishes this by
ISTRATION (FDA), TRANSGENIC.	latching onto (odorant) molecules and
Ochratoxins A term that refers to a group of	enhancing their aroma. Hence, it acts as a
related mycotoxins (i.e., toxic metabolites	kind of “helper” entity in bringing about the
produced by fungi) that are produced by	ability to smell certain odorants present in
some Aspergillus species and some Penicil-	low concentration. See also PROTEIN.
lium species of fungi (e.g., Penicillium viri-	OECD See ORGANIZATION FOR ECONOMIC COOP-
dicatum). These particular fungi tend to	ERATION AND DEVELOPMENT.
produce ochratoxins when they grow in	Office International des Epizootics	S e e
damaged grain (e.g., during grain storage),	INTERNATIONAL OFFICE OF EPIZOOTICS (OIE).
especially when grain temperature is above	OGM See GMO.
4°C (40°F) and grain moisture content is	OH43 Gene in plants (e.g., corn/maize) that
above 18%. Ochratoxin A is a very carcino-	causes production of a seed coat more resis-		O
genic (cancer-causing) toxin when con-	tant to tearing. Greater tear-resistance results
sumed by humans. When dairy cattle	in a lower incidence of fungi infestation in
consume ochratoxin A-containing grain, the	seed, which results in less mycotoxin pro-
ochratoxin A soon appears in the milk pro-	duction in seed. See also GENE, FUNGUS, AFLA-
duced by those cows. See also MYCOTOXINS,	TOXIN, MYCOTOXINS.
TOXIN, FUNGUS, PENICILLIUM, CARCINOGEN.	OIE Office International des Epizootics. See
Octadecanoid/Jasmonate Signal Complex	also INTERNATIONAL OFFICE OF EPIZOOTICS (OIE).
A chemical signal created and emitted by	OIF See OSTEOINDUCTIVE FACTOR.
certain plants in response to those plants	Oils See FATTY ACID.
being wounded (e.g., via chewing) by	Oleic Acid A fatty acid naturally present in the
insects. The octadecanoid/jasmonate signal	fat of animals and also in oils extracted from
complex then causes the production and also	oilseed plants (soybean, canola, etc.). For
emission of volatile chemicals such as volic-	example, the soybean oil produced from tra-
itin, which attract certain types of wasps that	ditional varieties of soybeans tends to con-
are natural enemies of those insects which	t a i n 2 4 % o l e i c a c i d . S e e	a l s o
initially wounded the plants. Thus, the octa-	MONOUNSATURATED FATS, FATTY ACID, FATS,
decanoid/jasmonate signal complex is a cru-	CANOLA, SOYBEAN PLANT, SOYBEAN OIL, HIGH-
cial part of an (indirect) defense mechanism	OLEIC OIL SOYBEANS, COSUPPRESSION.

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

© 2002 by CRC Press LLC

NUCLEOTIDE,

CHARIDES,

CHARIDES,

GLYCOGEN,

R I D E S ,

Oleosomes The storage bodies for lipids (fats) in the seeds of certain plants. See also LIPIDS,

FATS, FATTY ACID.

Oligionucleotide See OLIGONUCLEOTIDE.

Oligofructans See FRUCTAN, FRUCTOSE OLIGO-

SACCHARIDES.

Oligofructose See FRUCTOSE OLIGOSACCHARIDES.

Oligomer A relatively short (the prefix oligomeans few, slight) chain molecule (polymer) that is made up of repeating units (e.g., XAXAXAXA or XXAAXXAAXXAA, etc.). Short polymers consisting of only two repeating units are called dimers, those of three repeating units are called trimers. Longer units are called polymers (i.e., many units). As a rule of thumb, oligomers consisting of 11 or more repeating units are called polymers. See also POLYMER.

Oligonucleotide Synonymous with oligodeoxyribonucleotide, they are short chains of nucleotides (i.e., single-stranded DNA or RNA) that have been synthesized (made) by chemically linking together a number of specific nucleotides. Oligonucleotides (also called, simply “oligos”) are used as synthetic (man-made) genes, DNA probes, and in sitedirected mutagenesis. See also

GENE, DNA PROBE, OLIGOMER, SITE-DIRECTED

OMUTAGENESIS, GENE MACHINE, DEOXYRIBONUCLEIC ACID (DNA), RIBONUCLEIC ACID, SYNTHESIZING (OF DNA MOLECULES).

Oligonucleotide Probes Short chain fragments of DNA that are used in various gene analysis tests (e.g., the single base change in DNA that causes sickle-cell anemia). See

also OLIGONUCLEOTIDE, DEOXYRIBONUCLEIC

ACID (DNA), DNA PROBE, GENE MACHINE.

Oligopeptide A relatively short chain molecule made up of amino acids linked by peptide bonds. See also PEPTIDE, POLYPEPTIDE

(PROTEIN), OLIGOMER, AMINO ACID.

“Oligos” See OLIGONUCLEOTIDE.

Oligosaccharides Relatively short molecular chains made of up to 10–100 simple sugar (saccharide) units. These sugar (i.e., carbohydrate) chains are frequently attached to protein molecules. When this happens, the resulting molecule is known as a glycoprotein, i.e., a hybrid molecule that is part protein and part sugar. The oligosaccharide portion affects a protein’s conformation(s) and biological

© 2002 by CRC Press LLC

activity. The oligosaccharide (carbohydrate) portion of a glycoprotein functions as a mediator of cellular uptake of that glycoprotein. Glycosylation thus affects the length of time the molecule resides in the bloodstream before it is taken out of circulation (serum lifetime).

It is thought that blood group (A, B, O, etc.) is based upon an oligosaccharide concept. For example, different oligosaccharide “branches” on a given glycoprotein (e.g., tissue plasminogen activator) could cause that glycoprotein to be perceived by the body’s immune system to be another (incorrect) blood type, thus provoking an immune response against it. Oligosaccharides play a critical role in numerous disease processes (bacterial and viral infection processes, cancer metastasis processes, inflammation processes, etc.). For example, oligosaccharide “chains” extending from the exterior membrane plasma membrane of cells are utilized by bacteria (and inflammation-triggering immune system cells) to latch onto cells and facilitate entry into cells. See also POLYSAC-

CHARIDES, CELL, CONFORMATION, MONOSACCHA- F U R A N O S E , P E N T O S E , P Y R A N O S E ,

GLYCOFORM, FRUCTOSE OLIGOSAC-

GLYCOPROTEIN, MANNANOLIGOSAC-

TISSUE PLASMINOGEN ACTIVATOR

(tPA), OLIGOMER, SEROLOGY, HUMORAL IMMU-

NITY, CELLULAR IMMUNE RESPONSE, METASTASIS,

ADHESION MOLECULES, HEMAGGLUTININ (HA),

TRANSGALACTO-OLIGOSACCHARIDES.

Omega-3 Fatty Acids More properly called “n-3 fatty acids.” See also N- 3 FATTY ACIDS.

Omega-6 Fatty Acids More properly called “n-6 fatty acids.” See also N- 6 FATTY ACIDS.

Oncogenes Genes within a cell’s DNA that code for receptors (proteins on outer surface of cell membrane) for a cellular growth factor (e.g., epidermal growth factor). Via that coding-for of applicable receptors (or other protein molecules that are part of the signal transduction process of a cell), oncogenes “turn on” the process of cell division (replication) at appropriate time(s) during the life of each cell in an organism. When oncogenes are mutated (via exposure to cigarette smoke or ultraviolet light, etc.), those oncogenes can become cancer-causing genes, some of which (e.g., erythroblastosis virus gene) are

almost identical to the gene for epidermal growth factor (EGF) receptor (i.e., oncogene is a “deformed copy” of that gene). Such mutated oncogenes code for (i.e., cause to be made) proteins (protein kinases, protein phosphorylating enzymes, etc.) that trigger uncontrolled cell growth. They sometimes may consist of a human chromosome that has viral nucleic acid material incorporated into it and is a permanent part of that chro-

mosome. See also GENE, CELL, DEOXYRIBONUCLEIC ACID (DNA), BRCA GENES, HER-2 GENE,

ras GENE, MEIOSIS, CARCINOGEN, RIBOSOMES,

PROTEIN, TYROSINE KINASE, ENZYME, CHROMO-

SOME, PLASMA MEMBRANE, EPIDERMAL GROWTH

FACTOR (EGF), SIGNAL TRANSDUCTION, CODING

SEQUENCE, TUMOR, CANCER, PROTO-ONCOGENES,

GENETIC CODE, RECEPTORS, MUTAGEN.

Open Reading Frame (ORF) Region of a gene (DNA) that contains a series of triplet (bases) coding for amino acids without any termination codons. The ORF sequence is potentially translatable into a protein, but the presence of an open reading frame (sequence) does not guarantee that a protein molecule will be produced (by cell ribo-

some). See also GENE, DEOXYRIBONUCLEIC ACID

(DNA), AMINO ACID, PROTEIN, CODING SEQUENCE,

GENETIC CODE, TRANSLATION, CELL, RIBOSOMES.

Operator Also known as the “o locus.” The site on the DNA to which a repressor molecule binds to prevent the initiation of transcription. The operator locus is a distinct entity and exists independently of the structural genes and the regulatory gene. It is the structural/biochemical “switch” with which the operon is turned on or off, and it controls the transcription of an entire group of coordinately induced genes. One type of mutation of the operator locus is called operator constitutive mutants. Constitutive mutants continually churn out the protein characteristic for that operon because the operon unit cannot be turned off by the repressor mole-

cule. See also OPERON, PROMOTER, REGULATORY GENES, REPRESSION (OF GENE TRANSCRIPTION/TRANSLATION), REPRESSOR (PROTEIN),

STRUCTURAL GENE, STRUCTURAL GENOMICS.

Operon A gene unit consisting of one or more genes that specify a polypeptide and an operator unit that regulates the structural gene,

i.e., the production of messenger RNA (mRNA) and hence, ultimately, of a number of proteins. Generally an operon is defined as a group of functionally related structural genes mapping (being) close to each other in the chromosome and being controlled by the same (one) operator. If the operator is “turned on,” then the DNA of the genes comprising the operon will be transcribed into mRNA, and down the line specific proteins are produced. If, on the other hand, the operator is “turned off,” then transcription of the genes does not occur and the production of the operon-specific proteins does not occur.

See also OPERATOR, TRANSCRIPTION.

	Optical Activity The capacity of a substance
	to rotate the plane of polarization of plane-
	polarized light when examined in an instru-
	ment known as a polarimeter. All com-
	pounds that are capable of existing in two
	forms that are nonsuperimposable mirror
	images of each other exhibit optical activity.
	Such compounds are called stereoisomers
	(or enantiomers or chiral molecules) and the
	two forms arise because compounds having
	asymmetric carbon atoms to which other
	atoms are connected may arrange themselves
	in two different ways. See also STEREO-
		O
	ISOMERS, ENANTIOMERS, CHIRAL COMPOUND.
	Optical Density (OD) The absorbance of
	light of a specific wavelength by molecules
	normally dissolved in a solution. Light
	absorption depends upon the concentration
	of the absorbing compound (chemical
	entity) in the solution, the thickness of the
	sample being illuminated, and the chemical

nature of the absorbing compound. An analytical instrument known as a spectrophotometer is used to (quantitatively) express the amount of a substance (dissolved) in a solution. Mathematically, this is accomplished using the Beer-Lambert Law. See

also SPECTROPHOTOMETER, ABSORBANCE (A). Optimum Foods See NUTRACEUTICALS, PHYTO-

CHEMICALS.

Optimum pH The pH (level of acidity) at which maximum growth occurs or maximal enzymatic activity occurs, or at which any reaction occurs maximally. See also ENZYME.

Optimum Temperature The temperature at which the maximum growth occurs or

© 2002 by CRC Press LLC

maximal enzymatic activity occurs, or at which any reaction occurs maximally. See

also ENZYME, ENSILING.

Optrode A fiberoptic sensor made by coating the tip of a (glass) optic fiber with an antibody that fluoresces when the antibody comes in contact with its corresponding antigen. Alternatively, the fiber tip is sometimes coated with a dye that fluoresces when the dye comes in contact with specific chemicals (oxygen, glucose, etc.).

Functionally, a beam of light is sent down the fiber and strikes (“pumps”) the fluorescent complex, which then fluoresces (releases light of a specific wavelength). The light produced by fluorescence travels back up the same optic fiber and is detected by a spectrophotometer upon its return. By application of the Beer-Lambert Law, quantitative detection/measurement of the antigen or chemical in vivo in, e.g., a patient’s bloodstream is possible. See also ANTIGEN, IN VIVO ,

ANTIBODY, GLUCOSE (GLc), SPECTROPHOTOMETER.

Oral Cancer Also sometimes known as “cancer of the mouth,” this is a cancer involving the tissues lining the human mouth. Causes include consumption by humans of carcinogens (tobacco products, certain mycotoxins,

Oetc.). Oral cancerous cells arise from precancerous mouth lesions known as oral leukoplakia. During 2000, research by Frank Meyskins and William Armstrong indicated that consumption of Bowman-Birk trypsin inhibitor (BB T.I.) derived from soybeans, in a manner that ‘bathes’ mouth tissues in BB T.I. (for an extended period of time) inhib-

its the development of oral leukoplakia. See

also CANCER, TUMOR, MUTAGEN, MYCOTOXINS,

TRYPSIN INHIBITORS.

Oral Leukoplakia See ORAL CANCER.

ORF See OPEN READING FRAME (ORF).

Organelles Membrane-surrounded structures found in eucaryotic cells; they contain enzymes and other components required for specialized cell function (e.g., ribosomes for protein synthesis, or lysosomes for enzymatic hydrolysis). Some organelles such as mitochondria and chloroplasts contain DNA and can replicate autonomously (from the rest of the cell). See also NUCLEUS, EUCARY-

OTE, ENZYME, RIBOSOMES, LYSOSOME.

Organism Refers to any living plant, animal, bacteria, fungus, virus, etc. Also (e.g., in certain international treaties such as the Convention on Biological Diversity), this term includes things (e.g., seeds, spores, eggs) possessing the potential to become plants, animals, fungi, etc. See also BIOLOGY, BACTE-

RIA, FUNGUS, VIRUS, CONVENTION ON BIOLOGICAL

DIVERSITY (CBD).

Organismos Geneticamente Modificados

See GMO.

Organization for Economic Cooperation and Development (OECD) An international organization comprised of the world’s wealthiest (most developed) nations, originally established in 1960 to study trade and related matters. In 1991, the OECD’s Group of National Experts on Safety in Biotechnology (GNE) completed a document entitled Report on the Concepts and Principles Underpinning Safety Evaluations of Food Derived from Modern Biotechnology. The “aim of that document was to elaborate the scientific principles to be considered (i.e., by OECD member nations’ regulatory agencies) in evaluating the safety of new foods and food components” (e.g., genetically modified soybeans, corn/maize, potatoes,

etc.). See also BIOTECHNOLOGY, SOYBEAN PLANT, GNE, CANOLA, MUTUAL RECOGNITION

AGREEMENTS (MRA).

Organogenesis The production of entire organs, usually from basic cells, such as fibroblasts, and structural material such as

collagen. See also COLLAGEN, FIBROBLASTS.

Origin Point or region where DNA (deoxyribonucleic acid) replication is begun. Often abbreviated “Ori.” See also REPLICATION (OF

VIRUS), REPLICATION FORK.

Orphan Drug The name of the legal status granted by the Food and Drug Administration’s Office of Orphan Products Development (to certain pharmaceuticals). This classification provides the sponsors of those pharmaceuticals with special tax and other financial incentives (e.g., market monopoly for a limited time). If companies feel that they possess a cure (drug) for a certain disease, but the number of potential patients is below a certain number and there is potential competition from rival companies, then the

© 2002 by CRC Press LLC