Biotechnology

Transformation The process in which free
DNA is transferred directly into a competent
recipient cell. The direct transfer of genetic
material from donor to recipient. The acqui-
sition (e.g., by bacteria cells) of new genetic
markers (new traits coded for by the new
DNA) via the process of transformation. See
also
DEOXYRIBONUCLEIC ACID
 (
DNA
),
TRANSFEC-
TION
,
MARKER
 (
GENETIC MARKER
).
Transforming Growth Factor-Alpha (TGF-
alpha) An angiogenic growth factor pro-
duced by tumor cells. It is able to induce
specific malignant characteristics in normal
cells (such as fibroblasts), thereby “trans-
forming” those cells. TGF-alpha appears to
possess a variety of potentially useful phar-
maceutical properties, such as powerful
stimulation of scar tissue formation follow-
ing wounding of a tissue, as indicated by
preliminary research. See also 
TRANSFORMING
GROWTH FACTOR
-
BETA
  (
TGF
-
BETA
),
GROWTH
FACTOR
,
NERVE GROWTH FACTOR
 (
NGF
),
TUMOR
,
FIBROBLASTS
,
ANGIOGENIC GROWTH FACTORS
.
© 2002 by CRC Press LLC

T
Transforming Growth Factor-Beta (TGF-
beta) An angiogenic growth factor pro-
duced by tumor cells, it is able to induce
specific malignant characteristics in normal
cells (such as fibroblasts), thereby “trans-
forming” those cells. TGF-beta stimulates
blood vessel growth, even though it inhibits
the division of endothelial cells. TGF-beta is
a strong “attracting agent” for macrophages
(i.e., TGF-beta is chemotactic), and appears
to be responsible for the high concentrations
of macrophages often found in tumors. TGF-
beta has shown immunosuppressive activity
(i.e., it suppresses the immune system). For
example, transforming growth factor-beta
works together with osteoinductive factor
(OIF) to promote bone-formation by first
causing connective tissue cells to grow
together to form a matrix of cartilage (e.g.,
across a bone break); bone cells slowly
replace that cartilage. See also 
TRANSFORMING
GROWTH FACTOR
-
ALPHA
  (
TGF
-
ALPHA
),
GROWTH
FACTOR
,
OSTEOINDUCTIVE FACTOR
 (
OIF
),
IMMUN-
OSUPPRESSIVE
,
NERVE GROWTH FACTOR
  (
NGF
),
TUMOR
,
FIBROBLASTS
,
ANGIOGENIC GROWTH FAC-
TORS
,
MITOGEN
,
ENDOTHELIAL CELLS
,
CHEMOT-
AXIS
,
MACROPHAGE
.
Transgalacto-oligosaccharides A “family” of
oligosaccharides (produced via enzymatic
conversion of lactose, using 
β-glucosidase
enzyme); some of which help to foster the
growth of beneficial bifidobacteria in the
lower colon of monogastric animals
(humans, swine, etc.). See also 
OLIGOSACCHA-
RIDES
,
PREBIOTICS
,
BACTERIA
,
BIFIDOBACTERIA
,
BIFIDUS
,
ENZYME
.
Transgene A “package” of genetic material
(i.e., DNA) that is inserted into the genome
of a cell via gene splicing techniques. May
include promoter(s), leader sequence, termi-
nation codon, etc. See also 
DEOXYRIBO-
NUCLEIC ACID
  (
DNA
),
GENE SPLICING
,
GENOME
,
LEADER SEQUENCE
,
PROMOTER
,
GENETIC CODE
,
TERMINATION CODON
 (
SEQUENCE
),
GENETIC ENGI-
NEERING
,
CASSETTE
.
Transgenic An organism whose gamete cells
(sperm/egg) contain genetic material origi-
nally derived from an organism other than
the parents, or in addition to the parental
genetic material. See also 
GENETIC ENGINEER-
ING
,
GAMETE
,
NUCLEAR TRANSFER
.
Transgressive Segregation A plant breeding
(propagation) technique, in which geneti-
cally very different members of the same
species are mated with each other. The off-
spring of that mating can be more healthy,
productive (e.g., fast growing), and uniform
than their parents, a phenomenon known as
“hybrid vigor.” See also 
GENETICS
,
SPECIES
,
F
1
HYBRIDS
,
HYBRIDIZATION
 (
PLANT GENETICS
).
Transit Peptide A peptide that, when fused to
a protein, acts to transport that protein
between compartments within eucaryotic
cells. Once inside the “destination compart-
ment,” the transit peptide is cleaved off the
protein and that protein is then free (to do
its designed task). See also 
PEPTIDE
,
PROTEIN
,
EUCARYOTE
,
CELL
,
FUSION PROTEIN
,
GATED
TRANSPORT
,
VESICULAR TRANSPORT
,
CHLOROPLAST
TRANSIT PEPTIDE
 (
CTP
).
Transition Refers to the replacement (i.e., in
DNA or RNA molecule) of one purine by
another purine; or one pyrimidine by another
pyrimidine. See also 
PURINE
,
PYRIMIDINE
,
DEOXYRIBONUNCLEIC ACID
  (
DNA
),
RIBONUCLEIC
ACID
 (
RNA
),
BASE SUBSTITUTION
.
Transition State (in a chemical reaction) That
point in the chemical reaction at which the
reactants (i.e., chemical entities about to
react with each other) have been “brought to
the brink.” It is a point in the chemical reac-
tion process in which an “activated condi-
tion” is reached. From this point the
probability of the reaction going to comple-
tion and producing a product is very high.
The transition state separates (energetically)
products from reactants. It is viewed as being
at the top of the energy barrier separating
reactants and products. The reacting species
in the transition state can, because of their
location at the “top” of the energy barrier,
“fall” to either products or reactants. See also
CATALYST
,
ENDERGONIC REACTION
,
ACTIVATION
ENERGY
,
FREE ENERGY
,
CATALYTIC ANTIBODY
,
SEMISYNTHETIC CATALYTIC ANTIBODY
,
EXERGONIC
REACTION
.
Translation The process whereby the genetic
information present in an mRNA molecule
directs the order of incorporation of specific
amino acids, and hence the growth of the
polypeptide chain during protein synthesis.
One can think of translation as the process
© 2002 by CRC Press LLC

T
of translating one language into another. In
this particular case the nucleic acid-based
language represented by mRNA is translated
into the amino acid-based language of pro-
teins. See also 
CODING SEQUENCE
,
CODON
,
RIBO-
SOMES
,
MESSENGER RNA
 (
m
RNA
),
PROTEIN
,
GENE
,
GENETIC CODE
.
Translocation Genetic mutation in which a
section of a chromosome “breaks off” and
moves to a new (abnormal) position in that
(or a different) chromosome. See also 
GENE
,
C H R O M O S O M E S
,
G E N E T I C
C O D E
,
C O D I N G
SEQUENCE
,
TRANSPOSITION
,
DEOXYRIBONUCLEIC
ACID
 (
DNA
),
MUTATION
,
INTROGRESSION
,
JUMPING
GENES
,
HOT SPOTS
.
Transmembrane Proteins Refers to those
protein molecules that extend from one side
of a cell membrane to the other side of that
membrane. For example, G-proteins are
transmembrane proteins that act to accom-
plish signal transduction (i.e., convey “sig-
nal” from outside the cell to one or more
internal cell parts). EGF receptors bind to
EGF molecules (e.g., passing-by in the
blood), then both enter the cell (through the
cell membrane) together, where the EGF
stimulates growth/division of that cell. See
also
PROTEIN
,
CELL
,
PLASMA MEMBRANE
,
RECEP-
TORS
,
MEMBRANE
  (
OF A CELL
),
MEMBRANE
TRANSPORT
,
ABC TRANSPORTERS
,
EGF RECEPTOR
,
G
-
PROTEINS
,
CECROPHINS
  (
LYTIC PROTEINS
),
MAGAININS
,
SIGNAL TRANSDUCTION
,
SIGNALING
,
EPIDERMAL GROWTH FACTOR
 (
EGF
).
Transposable Element See
TRANSPOSON
.
Transposase An enzyme required for transpo-
sition to occur. It is coded for by the trans-
poson known as the P element. See also
TRANSPOSITION
,
TRANSPOSON
,
ENZYME
,
GENETIC
CODE
,
CODING SEQUENCE
.
Transposition Movement of a gene or set of
genes from one site in the genome to another
without a reciprocal exchange (of DNA).
See also 
GENE
,
JUMPING GENES
,
GENOME
,
TRANSPOSON
,
TRANSPOSASE
,
HOT SPOTS
,
DEOXY-
RIBONUCLEIC ACID
 (
DNA
).
Transposon A DNA (deoxyribonucleic acid)
sequence (segment of molecule) able to rep-
licate and insert one copy (of itself ) at a new
location in the genome (i.e., a transposition
of location). Discovered in 1950 by geneti-
cist Barbara McClintock in corn (maize)
plants (Zea mays L.); and in bacteria a
decade later by Joshua Lederberg.
Transposons can either carry genes along
one organism’s genome, or even into another
organism’s genome (e.g., via sexual conju-
gation, in bacteria). By such sexual conju-
gation, transposons can carry genes that
confer new phenotypic properties (e.g.,
resistance to certain antibiotics, for a given
bacterial cell). See also 
DEOXYRIBONUCLEIC
ACID
  (
DNA
),
REPLICATION
  (
OF VIRUS
),
GENOME
,
TRANSPOSITION
,
TRANSPOSASE
,
SEQUENCE
  (
OF A
DNA MOLECULE
),
CORN
,
JUMPING GENES
,
GENE
,
SEXUAL CONJUGATION
,
PHENOTYPE
,
CONJUGATION
.
Transversion The substitution of a purine for
a pyramidine, or of a pyramidine for a purine
(at a specific site, within a given nucleotide
in a molecule of DNA). See also 
NUCLEOTIDE
,
DEOXYRIBONUCLEIC ACID
 (
DNA
),
SINGLE
-
NUCLEO-
TIDE POLYMORPHISMS
  (
SNP
s
),
MUTATION
,
BASE
SUBSTITUTION
.
TRANSWITCH
®
A “sense” technology used
to “turn off “ (suppress) a gene (e.g., the one
that causes tomato to ripen) that causes an
unwanted effect (e.g., premature softening
of tomato). TRANSWITCH
®
 and its regis-
tered trademark are owned by DNA Plant
Technology Corp. See also 
GENE SILENCING
,
SUPPRESSOR GENE
,
SENSE
.
“Treatment” IND Regulations Food and Drug
Administration (FDA) regulations promul-
gated in 1987, to provide a more rapid for-
mal pharmaceutical approval mechanism
than the usual IND (Investigational New
Drug) regulatory approval process. Its pur-
pose is to enable drug developers to provide
promising experimental drugs to patients
suffering from immediately life-threatening
diseases or certain serious conditions (e.g.,
acquired immune deficiency syndrome, or
AIDS) before complete data on that drug’s
efficacy or toxicity are available. See also
IND
,
FOOD AND DRUG ADMINISTRATION
  (
FDA
),
DELANEY CLAUSE
,
KOSEISHO
,
COMMITTEE FOR
PROPRIETARY MEDICINAL PRODUCTS
 (
CPMP
).
Treatment Investigational New Drug See
“
TREATMENT
”
IND REGULATIONS
.
Trehalose A disaccharide (simple sugar) that
is naturally synthesized (manufactured) by
many plants and animals in response to the
stresses of freezing, heating, or drying. That
© 2002 by CRC Press LLC

T
is because trehalose protects certain proteins
(needed for life) and prevents loss of crucial
volatile (i.e., easily evaporated) compounds
from organisms during those stressful (dry,
frozen, or hot) conditions. Trehalose also
provides a source of quick energy after the
stressful conditions have passed. That is why
dried baker’s yeast (which contains up to
20% trehalose by weight) can be stored in
its dry state for many years, yet quickly leav-
ens bread dough within minutes of being
rehydrated (i.e., rewetted).
Trehalose accomplishes this protection
by forming a nonhygroscopic “glass” on the
surfaces of cells and large molecules. It
immobilizes and stabilizes large molecules
(e.g., proteins), but still allows water to dif-
fuse out so complete drying can occur. Thus,
trehalose holds potential as a food additive
to keep proteins (e.g., eggs) fresh in the dried
form. In 1991, the U.K. approved trehalose
for use in food, and the U.S. approved its
use in 2001. Trehalose hydrolyzes (e.g., dur-
ing digestion) into two molecules of glucose.
See also 
DISACCHARIDES
,
PROTEIN
,
GLUCOSE
(
GL
c
),
HYDROLYSIS
,
CONFORMATION
, “
SWITCH
”
PROTEINS
,
TERTIARY STRUCTURE
,
PROTEIN FOLD-
ING
.
Tremorgenic Indole Alkaloids A “family” of
toxic alkaloids (chemical compounds) that
are naturally produced (within some plants)
by certain fungi (which sometimes grow in
those plants). For example, the alkaloid
known as Penitrem D is produced by certain
fungi which grow in some grass species. It
causes tremors, weakness, lack of coordina-
tion, and convulsions in animals that con-
sume those fungus-infested grasses. See also
ALKALOIDS
,
TOXIN
,
FUNGUS
,
ENDOPHYTE
.
Triacylglycerols See
TRIGLYCERIDES
.
Trichoderma harzianum A microorganism
that possesses (natural) fungicide activity.
See also 
BACILLUS THURINGIENSIS
  (
B
.
t
.),
WHEAT
TAKE
-
ALL DISEASE
,
FUNGUS
,
FUNGICIDE
.
Trichosanthin An enzyme extracted from a
specific Chinese plant. It has been discov-
ered to “cut apart” the ribosomes in some
cells infected with the HIV (i.e., AIDS)
virus, thus potentially stopping the virus and
preventing infection of additional cells. See
also
RIBOSOMES
,
ACQUIRED IMMUNE DEFICIENCY
SYNDROME
  (
AIDS
),
ENZYME
,
PROTEIN
,
HUMAN
IMMUNODEFICIENCY VIRUS TYPE
1
 (
HIV-
1
), 
HUMAN
IMMUNODEFICIENCY VIRUS TYPE
2
 (
HIV-
2
).
Triglycerides The primary constituent of fats
or oils; triglycerides are molecules that con-
sist of three fatty acids attached to a glycerol
“molecular backbone.” More accurately
called triacylglycerols, although long-term
historical usage of “triglycerides” has made
the latter term more common. Similarly, the
term “diglyceride” is often used to refer to
those molecules which consist of two fatty
acids attached to a glycerol “molecular back-
bone.” “Diglycerides” (more accurately
called diacylglycerols) can result from the
splitting-off (i.e., hydrolysis) of one fatty acid
from a triacylglycerol (“triglyceride”) mole-
cule (e.g., during fat breakdown/oxidation);
or from the combination of two fatty acids
with glycerol (e.g., during synthesis of fats).
The “triglyceride level” in human blood-
stream refers to the blood’s content of non-
cholesterol total fats. Research during the
1990s provided evidence that high blood lev-
els of triglycerides in humans (e.g., immedi-
ately after meals) contribute to thrombosis.
See also 
FATS
,
THROMBOSIS
,
FATTY ACID
,
SAT-
URATED FATTY ACIDS
  (
SAFA
),
LPAAT PROTEIN
,
UNSATURATED FATTY ACID
,
HYDROLYSIS
,
OXIDA-
TION
  (
of fats/oils/lipids
),
ADIPOCYTES
,
FRUCTOSE
OLIGOSACCHARIDES
,
BIFIDUS
,
POLYUNSATURATED
FATTY ACIDS
 (
PUFA
),
DIACYLGLYCEROLS
.
Triploid Refers to organisms that possess three
sets of chromosomes, instead of the normal
two sets. Conversion of a diploid (i.e., two
sets of chromosomes) organism to triploid
can be done by man (certain fish, “seedless”
grapes, etc.). For example, fish are ordinarily
diploid. By exposing fish eggs to certain spe-
cific combinations of temperature and pres-
sure, immediately after fertilization of those
eggs, scientists can cause the resultant fish
to become triploid. Triploid fish are unable
to reproduce. This sterility is desired by man,
in order to prevent certain fish (e.g., those
that have been genetically engineered) from
mating with wild fish. Such induced (trip-
loid) sterility also prevents the (genetically
engineered) fish from wasting energy on the
act of reproduction, so they grow faster and
larger. That transfer (of energy use from
© 2002 by CRC Press LLC

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reproduction to growth) also holds true for
“seedless” grapes, watermelons, etc. See
also
DIPLOID
,
CHROMOSOMES
,
WHEAT
.
tRNA See
TRANSFER RNA
 (
t
RNA
).
Tropism Orientation movement of a sessile
organism in response to a stimulus. Move-
ment of curvature due to an external stimulus
that determines the direction of movement.
Also known as topotaxis. See also 
SESSILE
,
CHEMOTAXIS
.
Trypsin A proteolytic (protein molecular
chain-cutting) enzyme produced by the pan-
creas, to facilitate digestion within certain
animals. Trypsin cleaves polypeptide (pro-
tein) molecular chains on the carboxyl
(group) side of arginine and lysine units (res-
idues); and it is often utilized by man to
break apart protein molecules (e.g., to enable
scientists to study that protein’s constituent
peptides). See also 
ARGININE
 (
arg
),
LYSINE
 (
lys
),
PROTEIN
,
PEPTIDE
,
POLYPEPTIDE
 (
PROTEIN
),
PRO-
TEOLYTIC ENZYMES
,
PROTEASES
,
CHYMOTRYPSIN
,
TRYPSIN INHIBITORS
,
DIGESTION
 (
WITHIN ORGAN-
ISMS
),
COWPEA TRYPSIN INHIBITOR
 (
C
p
TI
).
Trypsin Inhibitors Compounds present in
certain legumes (soybeans, etc.) that inhibit
the activity (i.e., protein-cleavage, which
aids digestion) of proteases (i.e., protein-
cleaving enzymes such as trypsin or chymot-
rypsin) in the digestive systems of monogas-
tric (single-stomach) animals (which include
swine, poultry, and humans). Trypsin inhib-
itors present in traditional varieties of soy-
beans (botanical name Glycine max (L.)
Merrill) include:
• the Kunitz trypsin inhibitor (TI), which
was first isolated and crystallized by M.
Kunitz in 1945. It combines tightly with
molecules of trypsin on a 1:1 basis, and
thereby reduces the rate of protein-
cleavage effected by the trypsin
enzyme; which inhibits the animal’s
digestion of protein(s).
• the Bowman-Birk trypsin inhibitor
(BB T.I.), first described by D. E. Bow-
man in 1944. It combines with mole-
cules of trypsin and chymotripsin, and
thereby reduces the rate of protein-cleav-
age effected by the trypsin and
chymotrypsin enzymes, which inhibits
the animal’s digestion of protein(s).
NOTE: During 2000, research by
Frank Meyskins and William Arm-
strong indicated that consumption of
BB T.I. in a manner that ‘bathes’ mouth
tissues in it (for extended period of
time) inhibits the development of the
precancerous mouth lesions that can
become oral cancer.
• certain free fatty acids and their acyl
CoA esters, which reduce the rate of
protein-cleavage effected by the trypsin
enzyme inhibiting the animal’s diges-
tion of protein(s).
Heating of soybeans to a temperature of 212°
(100°C) for 15 min causes these trypsin
inhibitors to be rendered inactive in soy-
beans, so the animal’s digestion is unim-
peded when it is fed soy that has been thus
heated. See also 
TRYPSIN
,
CHYMOTRYPSIN
,
SOY-
BEAN PLANT
,
PROTEIN
,
PROTEASES
,
ENZYME
,
PRO-
T E O L Y T I C
E N Z Y M E S
,
D I G E S T I O N
  (
W I T H I N
ORGANISMS
),
POLYPEPTIDE
 (
PROTEIN
),
BIOLOGICAL
ACTIVITY
,
ACYL C
o
A
,
COWPEA TRYPSIN INHIBITOR
(
C
p
TI
),
ORAL CANCER
.
Tryptophan (trp) An essential amino acid, it
is a precursor of the important biochemical
molecules indoleacetic acid, serotonin, and
nicotinic acid. 
L
-Tryptophan is used as a
common feed additive for livestock to ensure
that their diet includes an adequate amount
of this essential amino acid. See also 
ESSEN-
TIAL AMINO ACIDS
,
STEREOISOMERS
,
SEROTONIN
,
AMINO ACID
.
TSH See
THYROID STIMULATING HORMONE
 (
TSH
).
Tuberculosis See
MYCOBACTERIUM TUBERCULOSIS
.
Tubulin A cell protein required for cell mitosis
(i.e., the cell-reproduction process in which
a cell divides into two identical cells). When
the drugs paclitaxel or Taxol™ are adminis-
tered to the body (e.g., in chemotherapy),
they bind tubulin; which halts cell division
and causes apoptosis in the affected cells
(e.g., tumor cells) by binding Bc1-2 (a pro-
tein that prevents apoptosis in cells). See also
CELL
,
PROTEIN
,
MITOSIS
,
PACLITAXEL
,
TAXOL
,
CAN-
CER
,
CHEMOTHERAPY
,
APOPTOSIS
.