H U M A N

than 72.9 atmospheres — carbon dioxide becomes a dense (sort of) liquid. Some coffee processors have used supercritical carbon dioxide as a solvent to remove caffeine from coffee.

In 1995, Keith Johnston added the surfactant ammonium carboxylate perfluoropolyether to a supercritical carbon dioxide system containing water and proved that the large biological molecule bovine serum albumin dissolved inside the micelles that form via water droplet surrounded by fluoroether molecules. Subsequent to that, Eric Beckman proved that the protease subtilisin Carlsberg can be extracted from crude (impure) cell broth because that protease preferentially dissolves in a supercritical carbon dioxide/water system containing fluoroether amphiphiles as surfactants. See also

BIOLOGICAL ACTIVITY, SURFACTANT, MICELLE,

REVERSE MICELLE (RM), BROTH, PROTEASE,

SUPERCRITICAL FLUID, ALBUMIN.

Supercritical Fluid Refers to a material that has been heated to a temperature above its (normal atmospheric pressure) boiling point, but which is kept in a state that resembles a liquid via the application of high pressure. Less commonly, refers to a liquid that has been cooled to a temperature below its normal freezing point, but which is kept in a liquid state by various means. For example, water will remain “liquid” up to a temperature of 375°C (617°F) if it is placed under enough pressure. Ammonia will remain “liquid” up to a temperature of 133°C (271°F) if it is placed under enough pressure, despite

Sthe fact that ammonia normally becomes a gas (at standard atmospheric pressure) whenever the temperature is higher than –33.35°C (–30°F).

One predatory mite (Alaskozetes antarcticus) living in Antarctica is able to survive subfreezing temperatures by preventing ice crystals from forming (i.e., supercritical water) inside its body, even when the environmental temperature is below the freezing point (i.e., supercritical). Most supercritical fluids have unique physical properties (e.g., they are often better solvents than their true liquid forms). Some supercritical fluids (e.g., supercritical carbon dioxide) can be used to

extract biological molecules (e.g., chlorophyll) from mixtures (e.g., ground-up plant leaves). After the biological molecule has dissolved out of the mixture, the biological molecule is recovered by releasing pressure so the carbon dioxide returns to gaseous form, and drifts away. See also SUPERCRITICAL

CARBON DIOXIDE.

Superoxide Dismutase (SOD) S e e

SUPEROXIDE DISMUTASE (hSOD).

Suppressor Gene A gene that can reverse the effect of a specific type of mutation in other genes, such as a premature termination sequence. See also GENE, TRANSWITCH®.

Suppressor Mutation A mutation that totally or partially restores a function lost by a primary mutation. It is located at a site in the gene different from the site of the primary mutation. See also GENE.

Suppressor T Cells Those T cells (thymusderived lymphocytes) that are triggered (after other types of T cells and other immune system cells have successfully fought off an infection) to slow down gradually and halt the body’s immune response (to the now-conquered pathogen). Discovered by Tomio Tada in 1971, suppressor T cells inhibit B cell activity. Failure to halt the immune response in time could lead to harm to the body by its own immune system. The B and T lymphocytes are indistinguishable in size and general morphology. Only the existence or nonexistence of certain proteins on their cell surfaces distinguishes the two classes of lymphocytes. See also CELLU-

LAR IMMUNE RESPONSE, PATHOGEN, B LYMPHO-

CYTES, T CELLS, AUTOIMMUNE DISEASE.

Supramolecular Assembly Refers to a very large molecular structure. See also SELF-

ASSEMBLY (OF A LARGE MOLECULAR STRUC-

TURE).

Surfactant Acronym for surface active agent. Amphipathic molecules (i.e., molecules that contain both a polar and nonpolar domain) which, due to their unique properties, position themselves at interfacial regions (surfaces) such as an oil/water interface. When surfactants are dissolved above a certain critical concentration in either water or nonpolar solvents, they may form micelles or reverse micelles, respectively. Surfactants are

© 2002 by CRC Press LLC

	commonly used to solubilize cell membrane	Merrifield developed a means to partially
	components and other hard-to-solubilize	automate the oligonucleotide assembly pro-
	molecules. See also AMPHIPATHIC MOLECULES,	cess. This led to automated machines that
	AMPHIPHILIC MOLECULES, MICELLE, REVERSE	can now rapidly manufacture a gene frag-
	MICELLE (RM), SDS, ADJUVANT (TO A HERBICIDE).	ment, gene, or DNA probe. See also GENE
	Sustainable Development D e fi n e d i n t h e	MACHINE, NUCLEOTIDE, OLIGOMER, OLIGONUCLE-
	1987 United Nations report “our common	OTIDE, SYNTHESIZING (OF PROTEINS), DEOXY-
	future” to be development (e.g., economic	R I B O N U C L E I C A C I D (D N A ), D N A P R O B E ,
	development) that meets the needs of the	SYNTHESIZING (OF OLIGOSACCHARIDES).
	present without compromising the ability of	Synthesizing (of oligosaccharides) Chemical
	future generations to meet their own needs.	synthesis (manufacture) of a known oli-
	See also CONSERVATION TILLAGE, GLOMALIN,	gosaccharide (structure). For example, a
	NO-TILLAGE CROP PRODUCTION, LOW-TILLAGE	synthesis of a defined-sequence oligosaccha-
	CROP PRODUCTION, EARTHWORMS.	ride (molecular) “branch” at a specific site
	Switch Proteins Refers to certain protein mol-	on a glycoprotein in order to “cover up” an
	ecules that signal a plant when environmen-	antigenic site on that glycoprotein molecule
	tal conditions are so dry (or cold, etc.) that	(e.g., so the glycoprotein can be used as a
	the plant needs to protect itself (via extreme	pharmaceutical). See also OLIGOSACCHARIDES,
	measures) to survive. See also TREHALOSE,	GLYCOPROTEIN, ANTIGEN, ANTIGENIC DETERMI-
	PROTEIN, SIGNALING, TRANSCRIPTION FACTORS,	NANT, RESTRICTION ENDOGLYCOSIDASES.
	CBF1, SEQUENCE (OF A DNA MOLECULE), REGU-	Synthesizing (of proteins) Chemical synthe-
	LATORY SEQUENCE.	sis (manufacture) of a known protein mole-
	Switching (e.g., on/off) of Genes See G E N E ,	cule. Devised based upon the solid phase
	GENETIC CODE, CODING SEQUENCE, DEOXYRIBO-	synthesis methodology developed by Robert
	NUCLEIC ACID (DNA), SEQUENCE (OF A DNA MOL-	Bruce Merrifield in 1963, the desired pro-
	ECULE), REGULATORY SEQUENCE, TRANSCRIPTION	teins are assembled by repetitive coupling of
	FACTORS, CBF1, COLD HARDENING, CESSATION	the constituent amino acids to a growing
	CASSETTE.	polypeptide backbone, which itself is
	Syk Protein See MAST CELLS.	attached to a polymeric support (substrate).
	Symbiotic Refers to the mutually beneficial	This procedure has been automated, so it is
	living together of organisms, in an intimate	now possible to make proteins via automated
	association or union. For example, lichen are	synthesizers. See also PROTEIN, POLYPEPTIDE
	a life form consisting of algae and a fungus	(PROTEIN), AMINO ACID, SUBSTRATE (STRUC-
	growing together as a unit on a solid surface	TURAL), COMBINATORIAL CHEMISTRY, SYNTHE-
	(e.g., a tree trunk or a rock). Each helps the	SIZING (OF DNA MOLECULES).
	other to survive and grow. See also ALGAE,	Synthetase See SYNTHASE.
			S
	FUNGUS, RHIZOBIUM (BACTERIA), PHARMACOEN-	Systematic Activated Resistance See SYSTEMIC
	VIROGENETICS, ANTIBIOSIS.	ACQUIRED RESISTANCE (SAR).
	Synthase See ACC SYNTHASE, EPSP SYNTHASE,	Systematics An extension of taxonomy, it is the
	ENZYME, CP4 EPSPS, CITRATE SYNTHASE (CSb)	scientific classification of living organisms.
	GENE, GLUTAMINE SYNTHETASE, ALS GENE.	Systemic Acquired Resistance (SAR) D i s -
	Synthesizing (of DNA molecules) The build-	covered in 1992 (applicable to harpin-
	ing (i.e., polymerization manufacture) of a	induced SAR) and in 1996 by J.A. Ryals,
	known sequence of nucleotides into a chain	U.H. Neuenschwander, M.G. Willits, A.
	called an oligonucleotide (of which genes	Molina, H.-Y. Steiner, and M.D. Hunt, SAR
	are made) or DNA (deoxyribonucleic acid).	is a sort of “immune (cascade) response” by
	Invented by Har Goribind Khorana and his	a plant, against infection (by bacteria, fun-
	colleagues at the University of Wisconsin,	gus, etc.). One example of this is the pro-
	Madison, in 1968, this process enables sci-	duction of stress proteins or pathogenesis-
	entists to create genes or gene fragments for	related proteins when certain plants are
	use in research. In 1973, Robert Bruce	attacked by certain pathogens. Via such SAR

© 2002 by CRC Press LLC

response triggered by low-level fungal or	approved harpin protein to be applied to
viral infection, many plants successfully	some crops in order to trigger SAR against
resist fungal/bacterial/viral attacks.	certain plant diseases. See also PATHOGENESIS
In 1998, the U.S. Environmental Protec-	RELATED PROTEINS, PHYTOALEXINS, R GENES,
tion Agency (EPA) approved one herbicide	ISOFLAVONES, SOYBEAN PLANT, FUNGUS, IMMUNE
(COBRAR owned by Valent Corp.), whose	RESPONSE, VIRUS, PATHOGEN, STRESS PROTEINS,
active ingredient is the chemical lactofin, to	SALICYLIC ACID (SA), JASMONIC ACID, HARPIN,
be applied to soybean plants “at or near	CASCADE, WHITE MOLD DISEASE.
bloom stage” in order to trigger SAR against	Systemic Inflammatory Response Syndrome
white mold disease. In 2000, the U.S. EPA	See SEPSIS.

S

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T

T Cell Growth Factor (TCGF) Also known as Interleukin-2. See also INTERLEUKIN-2 (IL- 2).

T Cell Modulating Peptide (TCMP) A short protein chain that is thought to restrain certain types of T cells from attacking an (arthritis) afflicted patient’s tissues (mainly cartilage). Arthritis is caused by the sufferer’s own immune system attacking the body’s cartilage tissues. See also CYTOTOXIC

T CELLS, HELPER T CELLS (T4 CELLS), LYMPHOCYTE, SUPPRESSOR T CELLS, T CELL RECEPTORS,

AUTOIMMUNE DISEASE, TUMOR NECROSIS FACTOR

(TNF).

TCell Receptors Antibody-like transmembrane (i.e., across the cell’s surface membrane) proteins located on the surface of T cells. These trigger the (cellular) immune response that is mounted by T cells when these receptors bind to antigens (foreign pieces of antigenic protein) that have been “presented” to these receptors by an MHC protein which itself is located on the surface of phagocytic (i.e., scavenging, pathogeningesting) B lymphocyte. Antibodies in the blood recognize native antigen macromolecules (large molecules), whereas T cell receptors recognize fragments derived from those antigen macromolecules (upon presentation at the surface of B lymphocytes following ingestion and digestion by the

B lymphocytes). See also ANTIBODY, ANTIGEN,

MAJOR HISTOCOMPATIBILITY COMPLEX (MHC),

PROTEIN, T CELLS, CELLULAR IMMUNE RESPONSE,

PHAGOCYTE, B LYMPHOCYTES, CYTOTOXIC T CELLS,

HELPER T CELLS, SUPPRESSOR T CELLS.

TCells A class of (thymus-derived) lymphocytes that include helper T cells (also

known as T helper cells or TH cells), suppressor T cells, and cytotoxic T cells (also known as killer cells or CTL for cytotoxic

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

T lymphocyte). These cells mediate (i.e., control/direct) the cellular response of the human immune system in very complex ways. T cells are involved in the activation of B cells. See also CELLULAR IMMUNE

RESPONSE, CYTOTOXIC T CELLS, HELPER T CELLS

(T4 CELLS), LYMPHOCYTE, SUPPRESSOR T CELLS,

T CELL RECEPTORS, T CELL MODULATING PEPTIDE

(TCMP), ALLERGIES (FOODBORNE), DENDRITIC

CELLS, LEUKOTRIENES.

T Lymphocytes See T CELLS, LYMPHOCYTE,

LYMPHOKINES, THYMUS.

T-DNA See Ti PLASMID.

t-IND Treatment Investigational New Drug Application to the U.S. Food and Drug Administration (FDA). See also “TREATMENT”

IND REGULATIONS.

t-IND Treatment Investigational New Drug
Application to the U.S. Food and Drug
Administration (FDA). See also “TREATMENT”
IND REGULATIONS.
T3 See SAM-K GENE.
T4 Cells See HELPER T CELLS (T4 CELLS).
Tachykinins A class of neuropeptides (i.e.,
peptides produced by cells of the nervous
system; neurons) that includes neurokinin A,
neurokinin B, eledoisin, physalaemin, kassi-
nin, substance P, and substance K. Some of
these neuropeptides (e.g., Substance P) are
picked up by mast cells, lymphocytes, and/or	T
monocytes; and cause those three types of
immune system cells to release certain lym-
phokines (e.g., tumor necrosis factor, inter-
leukin-1 etc.), thus activating the immune
system. See also MAST CELLS, LYMPHOCYTE,
MONOCYTES, TUMOR NECROSIS FACTOR (TNF),
INTERLEUKIN-1 (IL- 1).
TAG See TRIACYLGLYCEROLS.
Taq DNA Polymerase A 94 kilodalton DNA
polymerase, which was originally isolated

© 2002 by CRC Press LLC