DEOXYRIBO-

gene is inserted via genetic engineering into a (fruit crop) plant’s genome, that causes greatly reduced production of the chemical compound S-adenosylmethionine (SAM) in that plant’s fruit. Because the SAM is normally converted (chemically) into l-ami- nocyclopropane-1-carboxylic acid (ACC) in the fruits of traditional vaieties of (fruit crop) plants, such sam-k gene-containing plants produce fruits which ripen/soften far slower than fruit from traditional varieties of those plants; which can reduce spoilage/loss in the harvest and transport of such fruit. That is because ACC is required for fruits to produce ethylene, the plant hormone which triggers (over-) ripening/softening of fruit. See

also GENE, BACTERIOPHAGE, ESCHERICHIA

COLIFORM (E. COLI), GENETIC ENGINEERING,

GENOME, ACC, ACC SYNTHASE.

Sanitary and Phytosanitary (SPS) Agreement The agreement to GATT/WTO via which WTO member nations agreed to base their technical barriers (regarding some imports, designed for the protection of human health or the control of animal and plant pests/diseases) only on an assessment of actual risks posed by the particular import in question; and to utilize only scientific methods in assessing those risks. See also

SANITARY AND PHYTOSANITARY (SPS) MEASURES,

WORLD TRADE ORGANIZATION (WTO), SPS.

Sanitary and Phytosanitary (SPS) Measures

Technical barriers (i.e., against some imports) that are designed for the protection of human health or the control of animal and

Splant pests/diseases. In the Sanitary and Phytosanitary (SPS) Agreement to GATT/WTO, the WTO member nations agreed to base their SPS measures only on an assessment of actual risks posed by the particular import in question, and to utilize only scientific

methods in assessing those risks. See also

SANITARY AND PHYTOSANITARY (SPS) AGREEMENT,

WORLD TRADE ORGANIZATION (WTO), SPS.

Saponification Alkaline hydrolysis of triacyl glycerols to yield fatty acid salts. The molecules thus produced are known as surfactants (surface active agents), commonly called soap. The process of soapmaking. See

also HYDROLYSIS.

Saponins A group of phytochemicals (i.e., sugars linked to a triterpene or a steroid molecular subunit) produced by certain plants (the soybean plant, spinach plant, tomatoes, potatoes, ginseng plant, etc.). Evidence suggests that human consumption of saponins (e.g., produced in soybeans) can help to lower a person’s blood content of low-density lipoproteins (LDLP) and can help prevent certain types of cancer. See also

PHYTOCHEMICALS, SUGAR MOLECULES, SOYBEAN

PLANT, LOW-DENSITY LIPOPROTEINS (LDLP), CAN-

CER, STEROID.

SAR Acronym for Systemic Acquired Resis-

tance. See also SYSTEMIC ACQUIRED RESISTANCE

(SAR).

Satellite DNA Many tandem repeats (identical or related) of a short basic repeating unit (in the DNA molecule). See also

NUCLEIC ACID (DNA).

Saturated Fatty Acids (SAFA) Fatty acids containing fully saturated alkyl chains (on their molecules). This means that the carbon atoms comprising the chains are held together by one carbon-to-carbon bond and not two or three. High levels of dietary SAFA have been related to increased blood cholesterol levels, which tends to lead to coronary heart disease (CHD) in humans. The sole exception is stearic acid (also known as stearate), which research has shown has no impact on the blood cholesterol levels of humans that consume it. Beef fat typically contains approximately 54% saturated fatty acids; sheep fat typically contains approximately 58% saturated fatty acids; pork fat typically contains approximately 45% saturated fatty acids; chicken fat typically contains approximately 32% saturated fatty acids.

In general, fats possessing the highest levels of saturated fatty acids tend to be solid at room temperature; and those fats possessing the highest levels of unsaturated fatty acids tend to be liquid at room temperature. That rule of thumb was the original “dividing line” between the terms “fats” and “oils,” respectively. See also FATTY ACID, DEHYDRO-

GENATION, CHOLESTEROL, MONOUNSATURATED

FATS, SAPONIFICATION, LPAAT PROTEIN, UNSAT-

URATED FATTY ACID, POLYUNSATURATED FATTY

© 2002 by CRC Press LLC

ACIDS (PUFA), CORONARY HEART DISEASE (CHD),

PALMITIC ACID, STEARATE (STEARIC ACID), HIGH-

STEARATE SOYBEANS, HIGH-STEARATE CANOLA.

Saxitoxins Paralytic poisons produced by certain shellfish. See also RICIN.

SBO Soybean oil.

Scab See FUSARIUM.

Scale-Up The transition step in moving a (chemical) process from experimental (e.g., “test tube,” small, bench) scale to a larger scale producing more or much more product that the bench scale (e.g., production of tons/year in a chemical plant). A process may require a number of scale-ups, with each scale-up producing more product than the last one.

Scanning Tunneling Electron Microscopy

See ELECTRON MICROSCOPY (EM).

SCP See SINGLE-CELL PROTEIN (SCP).

SDM Site-directed mutagenesis. See also SITE-

DIRECTED MUTAGENESIS (SDM).

SDS Sodium dodecyl sulfate. Also known as sodium lauryl sulfate (SLS). A surfactant commonly used in biochemical and biotechnological applications for the solubilization of membrane components and hard-to-solu- bilize (dissolve) molecules. For example, it is often utilized at high concentration in water solution (e.g., along with potassium acetate) to dissolve plant DNA samples (e.g., when a scientist wants to sequence that sample of plant DNA). The SDS/PA in water solution helps the scientist to separate out contaminants commonly present in samples from plant tissues (polysaccharides, proteins, etc.) because DNA molecules are much more soluble in SDS/PA solution than are those contaminant molecules. Above a critical concentration (CMC), SDS forms micelles in water which are thought to be responsible for its solubilizing action. SDS is also used in such items as shampoo. See also

CRITICAL MICELLE CONCENTRATION, MICELLE,

REVERSE MICELLE (RM), PROTEIN, MEMBRANE (OF

A CELL), SURFACTANT, DEOXYRIBONUCLEIC ACID

(DNA), POLYSACCHARIDES, SEQUENCING (OF DNA

MOLECULES), HEXADECYLTRIMETHYLAMMONIUM

BROMIDE (CTAB).

Seed-Specific Promoter See PROMOTER.

“Seedless” Fruits See TRIPLOID.

Selectable Marker Genes See MARKER (GENETIC

MARKER).

	Selectins Also called LEC-CAMs (leukocyte-
	cell adhesion molecules). A class of molecu-
	lar structurally related lectins that mediate
	(control, cause, etc.) the contacts between a
	variety of cells (e.g., leukocytes and endo-
	thelial cells), and function as cellular adhe-
	sion receptors. See also RECEPTORS, LECTINS,
	ADHESION MOLECULE, LEUKOCYTES, ENDOTHELIAL
	CELLS, ENDOTHELIUM, SIGNAL TRANSDUCTION.
	Selective Apoptotic Anti-Neoplastic Drug
	(SAAND) A category of pharmaceuticals
	that acts to prevent neoplastic growth (i.e.,
	cancer) by allowing normal cell apoptosis to
	occur again (e.g., by blocking an enzyme that
	is hindering normal apoptosis) in abnormal
	precancerous cells and cancerous cells.
	Examples of SAANDs include sulindac,
	which blocks phosphodiesterases (enzymes).
	See also NEOPLASTIC GROWTH, CANCER, TUMOR,
	APOPTOSIS, CELL, ENZYME, PHOSPHODIESTERASES.
	Selective Estrogen Effect A term used to
	describe how certain phytochemicals (fla-
	vones, flavonols, isoflavones, etc.) and phar-
	maceuticals (Evista/raloxifene, tamoxifen,
	etc.) possessing molecular structures that are
	similar to estrogen (a hormone) impart some
	beneficial effect on the human body when
	consumed by humans, without any of the
	adverse impacts of estrogen (e.g., promotion
	of the growth of certain tumors by estrogen).
	See also PHYTOCHEMICALS, FLAVONOLS, ISOFLA-
	VONES, FLAVONOIDS, ESTROGEN, PHYTOESTRO-
	GENS, PROSTATE, GENISTEIN (Gen).
	Selective Estrogen Receptor Modulators
		S
	Abbreviated SERM. This term refers to
	chemical compounds (isoflavones, the phar-
	maceuticals Evista/raloxifene and tamox-
	ifen, etc.) which impart some beneficial
	effect on the human body when consumed
	by humans, without any of the adverse
	impacts of estrogen (e.g., promotion of the
	growth of certain tumors by estrogen). See
	also SELECTIVE ESTROGEN EFFECT, ESTROGEN,
	ISOFLAVONES, PHYTOCHEMICALS.
	Self-Assembly (of a large molecular struc-
	ture) The essentially automatic ordering and
	assembly of certain molecules into a large
	structure. Examples of such large molecular
	structures (often called supramolecular

© 2002 by CRC Press LLC

DEOXYRIBO-

structures or supramolecular assemblies) include micelles, reverse micelles, ribosomes, peptide nanotubes, and Tobacco Mosaic Virus (TMV).

The first discovery of a self-assembling active biological structure occurred in 1955, when Heinz Frankel-Conrat and Robley Williams showed that TMV will reassemble into functioning, infectious virus particles (after TMV has been dissociated into its components via immersion in concentrated acetic acid). In the future, it is hoped that man will be able to “direct” the self-assembly of molecular structures which will:

• Serve as “cages” to carefully protect and deliver sensitive/unstable pharmaceuticals to targeted tissues within the body.

• Serve as “crucibles” (i.e., reaction vessels) for small-scale chemical reactions to occur within.

• Serve as computer logic or memory devices (i.e., bioelectronics).

• Serve as antibiotics.

		For example, during the 1990s, M. Reza
		Ghadiri created “peptide nanotubes” made
		via self-assembly of certain peptides into
		tubes (cylinders) of nanometer dimensions.
		These peptide nanotubes are “membrane
		active” (i.e., insert one end of themselves
		into the outer membrane of a cell), and cause
		the cell (e.g., pathogenic bacteria) contents to
		“leak out,” which kills the bacteria. See also
		MICELLE, REVERSE MICELLE (RM), RIBOSOMES,
		TOBACCO MOSAIC VIRUS (TMV), NANOCRYSTAL
	S
		MOLECULES, NANOSCIENCE, NANOTECHNOLOGY,
		NANOMETERS (NM), BIOELECTRONICS, ANTIBIOTIC,
		PATHOGEN, BACTERIA.
		Semisynthetic Catalytic Antibody An anti-
		body produced (e.g., via monoclonal anti-
		body techniques) in response to a carefully
		selected antigen (i.e., one of the molecules
		involved in the chemical reaction that you
		are trying to catalyze). Such an antibody is
		then made to be catalytic by “attaching” a
		(molecular) group that is known to catalyze
		the desired chemical reaction. This attaching
		is done either via chemical modification of
		the antibody, or via genetic engineering of
		the cell (DNA) that produces that antibody.

See also CATALYST, ANTIBODY, CATALYTIC

ANTIBODY, SITE-DIRECTED MUTAGENESIS (SDM),

MONOCLONAL ANTIBODIES (MAb), ANTIGEN,

GENETIC ENGINEERING, ABZYMES.

Senior Advisory Group on Biotechnology (SAGB) An association of approximately 35 of the largest European companies that are engaged in at least some form of genetic engineering research or production. Similar to America’s Biotechnology Industry Organization (BIO), the SAGB works with governments and the public to promote safe and rational advancement of genetic engineering and biotechnology. It was formed in 1989 and is based in Brussels, Belgium. See also

BIOTECHNOLOGY, GENETIC ENGINEERING, RECOM-

BINANT DNA (rDNA), JAPAN BIO-INDUSTRY ASSO-

CIATION, INTERNATIONAL FOOD BIOTECHNOLOGY

COUNCIL (IFBC), BIOTECHNOLOGY INDUSTRY

ORGANIZATION (BIO).

Sense Normal (forward) orientation of DNA sequence (gene) in genome. See also GENE

SILENCING, ANTISENSE (DNA SEQUENCE).

Sepsis Also known as systemic inflammatory response syndrome, this life-threatening condition (“septic shock”) occurs when the body’s immune system over-responds to infection (e.g., by gram-negative bacteria) in which release of bacterial endotoxin (lipopolysaccharide, or LPS) occurs. Those immune system cells (e.g., macrophages, etc.) overproduce numerous inflammatory agents (e.g., cytokines), which induce fever, shock, and sometimes organ failure. See also

GRAM-NEGATIVE (G-), BACTERIA, CYTOKINES,

ENDOTOXIN, MACROPHAGE.

Septic Shock See SEPSIS.

Sequence (of a DNA molecule) The specific nucleic acids that comprise a given segment of a DNA molecule. See also

NUCLEIC ACID (DNA), GENETIC CODE, GENE,

CHROMOSOMES, NUCLEIC ACIDS, CONTROL

SEQUENCES, SEQUENCING (OF DNA MOLECULES),

STRUCTU RAL GEN OMICS, CO MP LEMENTARY

(MOLECULAR GENETICS).

Sequence (of a protein molecule) The specific amino acids (and the order in which they are coupled together) that comprise a given segment of a protein molecule. See also PROTEIN,

AMINO ACID, STRUCTURAL GENE, GENOMICS,

© 2002 by CRC Press LLC

STRUCTURAL GENOMICS, SEQUENCING (OF PROTEIN

MOLECULES).

Sequence Map A pictorial representation of the sequence of amino acids in a protein molecule, the sequence of nucleic acids in a DNA molecule, or the sequence of oligosaccharide components in a glycoprotein/carbohydrate molecule. See also SEQUENCING (OF

DNA MOLECULES), SEQUENCING (OF PROTEIN MOL-

ECULES), SEQUENCING (OF OLIGOSACCHARIDES),

SEQUENCE (OF A DNA MOLECULE), SEQUENCE (OF

A PROTEIN MOLECULE), RESTRICTION MAP.

Sequencing (of DNA molecules) The process used to obtain the sequential arrangement of nucleotides in the DNA backbone. The cleavage into fragments (followed by separation of those fragments, which can then be sequenced individually) of DNA molecules by one of several methods: (1) a chemical cleavage method followed by polyacrylamide gel electrophoresis (PAGE) or capillary electrophoresis, (2) a method consisting of controlled interruption of enzymatic replication methods followed by PAGE, (3) a didexyl method utilizing fluorescent “tag” atoms attached to the DNA fragments, followed by use of spectrophotometry to identify the respective DNA fragments by their differing “tags” (which fluoresce at different wavelengths). This (fluorescent tag) variant of the dideoxy method can be automated to “decipher” large DNA molecules (i.e., genomes). Such automated machines are sometimes called “gene machines .” Sequencing of DNA was first done in the mid-1970s by Frederick Sanger. See also

POLYACRYLAMIDE GEL ELECTROPHORESIS (PAGE),

GENE MACHINE, DEOXYRIBONUCLEIC ACID (DNA),

SEQUENCE (OF A DNA MOLECULE), BASE EXCISION

SEQUENCE SCANNING (BESS), SHOTGUN SEQUENC-

ING, NANOPORE, NEAR-INFRARED SPECTROSCOPY

(NIR), COMPARATIVE SEQUENCING, BIOCHIPS.

Sequencing (of oligosaccharides) See RESTRIC-

TION ENDOGLYCOSIDASES, SEQUENCE MAP.

Sequencing (of protein molecules) The process used to obtain the sequential arrangement of amino acids in a protein molecule.

See also PROTEIN, AMINO ACID, SEQUENCE (OF A PROTEIN MOLECULE).

Sequon A (potential) site on a protein molecule’s “backbone” where a sugar molecule

(or a chain of sugar molecules, i.e., an oligosaccharide) may be attached. See also PROTEIN,

SUGAR MOLECULES, GLYCOPROTEIN, GLYCOGEN,

G L Y C O S Y L A T I O N , P R O T E I N E N G I N E E R I N G ,

OLIGOSACCHARIDES.

	Serine (ser) A nonessential amino acid; a bio-
	synthetic precursor of several metabolites,
	including cysteine, glycine, and choline. In
	1999, Solomon H . Snyder, Herman
	Wolosker, and Seth Blackshaw conducted
	research that showed that some mammals
	synthesize (manufacture) D-serine within
	their brains, and it functions as a neurotrans-
	mitter there. See also ESSENTIAL AMINO ACIDS,
	METABOLITE, CYSTEINE (cys), GLYCINE (Gly),
	CHOLINE, NEUROTRANSMITTER.
	Seroconversion The development of antibod-
	ies (specific to that disease-causing microor-
	ganism) in response to vaccination or natural
	exposure to a disease-causing microorgan-
	ism. See also SEROLOGY, ANTIBODY, IMMUNO-
	GLOBULIN, HUMORAL IMMUNITY, PATHOGEN,
	POLYCLONAL ANTIBODIES, PASSIVE IMMUNITY.
	Serologist See SEROLOGY.
	Serology A subdiscipline of immunology, con-
	cerned with the properties and reactions of
	blood sera. It includes the diverse techniques
	used for the “test tube” measurement of anti-
	body-antigen reactions, including blood typ-
	ing (e.g., for transfusions). See also MAJOR
	HISTOCOMPATIBILITY COMPLEX (MHC), OLIGO-
	SACCHARIDES, SERUM LIFETIME.
	Seronegative Refers to negative results of a
	serology test. See also SEROLOGY, HUMORAL
	IMMUNITY, ANTIBODY.
	Serotonin An important neurochemical whose
		S
	effects upon the human brain include mood
	elevation. Production of serotonin in the
	brain is increased by ingestion of the amino
	acid tryptophan (a chemical precursor to
	serotonin). Elevation of brain levels of sero-
	tonin can also be caused by consumption of
	the herb known as Saint John’s Wort
	(Hypericum perforatum), or by consumption
	of certain pharmaceuticals such as the anti-
	depressants Prozac™ (trademarked product
	of Eli Lilly & Company), Zoloft™ (trade-
	marked product of Pfizer, Inc.), or Paxil™
	(trademarked product of Smithkline Beecham
	PLC). In 1997, Marianne Regard and
	Theodor Landis discovered that humans

© 2002 by CRC Press LLC