Biotechnology

Angiogenesis Formation/development of new
blood vessels in the body. Discovered to be
triggered and stimulated by angiogenic
growth factors, in the early 1980s. Angio-
genesis is required for malignant tumors to
metastasize (spread throughout the body),
because it provides the (newly-created)
blood supply that tumors require. Angiogen-
esis is also crucial to the development of
glaucoma and macular degeneration (major
cause of blindness). The drug Thalidomide
is a potent inhibitor of angiogenesis, as are
the proteins angiostatin and endostatin. See
also
ANGIOGENIC GROWTH FACTORS
,
TUMOR
,
CAN-
CER
,
METASTASIS
,
ANTIANGIOGENESIS
,
CHIRAL
COMPOUND
,
ANGIOSTATIN
,
ENDOSTATIN
.
Angiogenesis Factors See
ANGIOGENIC GROWTH
FACTORS
.
Angiogenic Growth Factors P r o t e i n s   t h a t
stimulate formation of blood vessels (e.g., in
tissue being formed by the body to repair
wounds). See also 
FILLER EPITHELIAL CELLS
,
FIBROBLAST GROWTH FACTOR
  (
FGF
),
MITOGEN
,
ANGIOGENIN
,
ENDOTHELIAL CELLS
,
TRANSFORM-
ING GROWTH FACTOR
-
ALPHA
  (
TGF
-
ALPHA
),
TRANSFORMING GROWTH FACTOR
-
BETA
  (
TGF
-
BETA
),
PLATELET
-
DERIVED GROWTH FACTOR
(
PDGF
),
ANGIOGENESIS
.
Angiogenin One of the human angiogenic
growth factors, it possesses potent angio-
genic (formation of blood vessels) activity.
In addition to stimulating (normal) blood
vessel formation, angiogenin levels are cor-
related with placenta formation and tumor
growth (tumors require new blood vessels).
See also 
ANGIOGENIC GROWTH FACTORS
,
ANGIO-
GENESIS
,
TUMOR
,
GROWTH FACTOR
.
Angiostatin An antiangiogenesis (anti-blood-
vessel-formation) human protein discovered
by Judah Folkman. In combination with
endostatin, it has been shown to cause certain
cancer tumors in mice to shrink by cutting
off the creation of new blood vessels
required to “feed” a growing tumor.
Angiostatin acts to halt the creation of new
blood vessels by binding to ATP synthase
(an enzyme needed to initiate new blood ves-
sels). See also 
PROTEIN
,
ANTIANGIOGENESIS
,
ENDOSTATIN
,
CANCER
,
ATP SYNTHASE
,
TUMOR
.
Angstrom (Å) 10
–8
 cm (3.937 
× 10
–9
 inch).
Anion See
ION
.
Anneal The process by which the complemen-
tary base pairs in the strands of DNA combine.
See also 
BASE PAIR
  (
bp
),
DEOXYRIBONUCLEIC
ACID
 (
DNA
).
Anonymous DNA Marker Refers to a DNA
marker with a clearly identifiable sequence
variation (i.e., it is detectable by the specific
variation in its DNA sequence, whether or
not it occurs in or near a coding sequence).
See also 
DEOXYRIBONUCLEIC ACID
  (
DNA
),
SEQUENCE
 (
OF A DNA MOLECULE
),
MARKER
 (
DNA
SEQUENCE
),
MICROSATELLITE DNA
.
Antagonists Molecules that bind to certain
proteins (e.g., receptors, enzymes) at a spe-
cific (active) site on that protein. The binding
suppresses or inhibits the activity (function)
of that protein. See also 
RECEPTORS
,
ACTIVE
SITE
,
CONFORMATION
,
AGONISTS
,
ENZYME
,
ALLOSTERIC ENZYMES
.
Anterior Pituitary Gland S e e
P I T U I T A R Y
GLAND
.
Anthocyanidins Natural pigments (flavo-
noids) produced in blueberries (genus Vac-
cinium), blackberries (Rubus fruticosus),
cranberries (Vaccinium macrocarpon), cher-
ries (genus Prunus), black or purple carrots
(Daucus carota), and some types of grapes.
Consumption of anthocyanidins by humans
has been shown to be beneficial to eyesight
by aiding the health of the retina. Within the
human body, anthocyanidins act as antioxi-
dants (i.e., “quenchers” of free radicals), so
consumption apparently reduces the risk of
some cancers, coronary heart disease, eyesight
loss, and cataracts. See also 
PHYTOCHEMICALS
,
NUTRACEUTICALS
,
CAROTENOIDS
,
ANTIOXIDANTS
,
OXIDATIVE STRESS
,
CANCER
,
CORONARY HEART
DISEASE
  (
CHD
),
INSULIN
,
PROANTHOCYANIDINS
,
FOSHU
.
Anthocyanins See
ANTHOCYANIDINS
.
© 2002 by CRC Press LLC

A
Anti-Idiotype Antibodies See
ANTI
-
IDIOTYPES
.
Anti-Idiotypes Antibodies to antibodies. In
other words, if a human antibody is injected
into rabbits, the rabbit immune systems will
recognize the human antibodies as foreign
(regardless of the fact that they are antibod-
ies) and produce antibodies against them. To
the rabbit, the foreign antibodies represent
just another invader or nonself to be targeted
and destroyed. Anti-idiotypes mimic anti-
gens in that they are shaped to fit into the
antibody’s binding site (in lock-and-key
fashion). As such, anti-idiotypes can be used
to create vaccines that stimulate production
of antibodies to the antigen (that the anti-
idiotype mimics). This confers disease resis-
tance (to the pathogen associated with that
antigen) without the risk that a vaccine using
attenuated pathogens entails (i.e., that the
pathogen “revives” to cause the disease). See
also
ANTIBODY
,
MONOCLONAL ANTIBODIES
(
MA
b
),
ANTIGEN
,
IDIOTYPE
,
PATHOGEN
,
ATTENU-
ATED
 (
PATHOGENS
).
Anti-Interferon An antibody to interferon.
Used for the purification of interferons. See
also
A N T I B O D Y
,
I N T E R F E R O N S
,
A F F I N I T Y
CHROMATOGRAPHY
.
Anti-Oncogenes See
ONCOGENES
,
ANTISENSE
(
DNA SEQUENCE
).
Antiangiogenesis Refers to impact of any
compound that prevents angiogenesis (i.e.,
formation/development of new blood ves-
sels). Because angiogenesis is required for
malignant tumors to grow and/or metastasize
(spread), antiangiogenesis was proposed by
Judah Folkman in 1970 as a means to com-
bat cancer. Because angiogenesis is required
for embryonic development, antiangiogenic
drugs inhibit proper development/growth of
infants in the womb. Fumagillin, ovalicin,
and Thalidomide have been found to possess
antiangiogenic properties. Also, the human
proteins angiostatin and endostatin. See also
ANGIOGENESIS
,
ANGIOGENIC GROWTH FACTORS
,
TUMOR
,
CANCER
,
ANGIOSTATIN
,
ENDOSTATIN
,
GENISTEIN
.
Antibiosis Refers to the processes by which
one organism produces a substance that is
toxic or repellent to another organism (e.g.,
a parasite) that is attacking the first organ-
ism. For example, certain varieties of
corn/maize (Zea mays L.) naturally produce
chemical substances in their roots that are
toxic to the corn rootworm. See also 
ANTIBI-
OTIC
,
BACILLUS THURINGIENSIS
 (
B
.
t
.),
CORN
,
CORN
ROOTWORM
.
Antibiotic Coined by Selman Waksman during
the 1940s, this term refers to organic com-
pounds that are naturally formed and secreted
by various species of microorganisms and/or
plants. It has a defensive function and is often
toxic to other species (e.g., penicillin, origi-
nally produced by bread mold, is toxic to
numerous human pathogens). Antibiotics
generally act by inhibiting protein synthesis,
DNA replication, synthesis of cell wall (cyto-
plasmic membrane) constituents, inhibition
of required cell (e.g., bacteria) metabolic pro-
cesses, and nucleic acid (DNA and RNA)
biosynthesis, hence killing the (targeted bac-
teria) cells involved. Inorganic (e.g., certain
metals) molecules may also have antibiotic
properties. See also 
PATHOGEN
,
MICROORGAN-
ISM
,
PROTEIN
,
NUCLEIC ACIDS
,
PENICILLIN G
(
benzylpenicillin
),
SYMBIOTIC
,
GRAM STAIN
,
GRAM
-
NEGATIVE
,
ALLELOPATHY
,
BACTERIA
,
GRAM
-
POSI-
TIVE
,
CELL
,
ANTIBIOSIS
,
AUREOFACIN
,
PHOTORHAB-
DUS LUMINESCENS
,
BETA
-
LACTAM ANTIBIOTICS
,
METABOLISM
,
DEOXYRIBONUCLEIC ACID
  (
DNA
),
PLASMA MEMBRANE
,
RIBONUCLEIC ACID
 (
RNA
).
Antibiotic Resistance A property of a cell
(e.g.. pathogenic bacteria) that enables it to
avoid the effect of an antibiotic that had for-
merly killed or inhibited that cell. Ways this
can occur include: changing the structure of
the cell wall (plasma membrane); synthesis
(manufacture) of enzymes to inactivate the
antibiotic (e.g., penicillinases, which inacti-
vate penicillin); synthesis of enzymes to pre-
vent antibiotic entering cell; and active
removal of the antibiotic from the cell. For
example, the membrane transporter protein
molecules known as ABC transporters are
sometimes able to help pathogenic bacteria
resist certain antibiotics by transporting out
the antibiotic before it can kill the bacteria.
The ABC transporter is a V-shaped molecule
embedded in the (bacteria) cell’s plasma
membrane, with the open end of the “V”
pointed toward the interior of the cell. When
molecules of certain antibiotics (inside the
cell) contact the ABC transporter molecule,
© 2002 by CRC Press LLC

A
the two “arms” of the ABC transporter close
around the antibiotic molecule, the ABC
transporter flips over, and thereby sends the
antibiotic molecule out through the exterior
of the cell’s plasma membrane, replacing
some critical cell metabolic processes, with
(new) metabolic processes that bypass the
antibiotic’s (former) effect. See also 
CELL
,
PATHOGEN
,
PATHOGENIC
,
BACTERIA
,
ANTIBIOTIC
,
PLASMA MEMBRANE
,
ENZYME
,
PENICILLINASES
,
METABOLISM
,
ABC TRANSPORTERS
,
MYCOBACTE-
RIUM TUBERCULOSIS
.
Antibody Also called immunoglobulin, Ig. A
large defense protein that consists of two
classes of polypeptide chains, light (L)
chains and heavy (H) chains. A single anti-
body molecule consists of two identical cop-
ies of the L chain and two of the H chain.
They are synthesized (made) by the immune
system (B lymphocytes) of the organism.
The antibody is composed of four proteins
linked together to form a Y-shaped bundle
of proteins (looks somewhat like a slingshot
or two hockey sticks taped together at the
handles). The amino acid sequence that
makes up the stem (heavy chains) of the Y
(i.e., the handles of the taped together
hockey sticks) is similar for all antibodies.
The stem is known as the Fc region of the
antibody, and it does not bind to antigens,
but does have other regulatory functions.
The two arms of the Y are each made up
of two side-by-side proteins called light chains
and heavy chains (proteins are chains of amino
acids), with identical antigen-binding (ab)
sites on the tips of each “arm.” The antibody
is thus bivalent in that it has two binding sites
for antigen. Taken together, the two arms of
the Y are known as the Fab portions of the
antibody molecule. The Fab portions can be
cleaved from the antibody molecule with
papain (an enzyme that is also used as a meat
tenderizer) or the Fab portions can be pro-
duced by genetically engineered Escherichia
coli  (E. coli) bacteria. When a foreign mole-
cule (e.g., a bacterium, virus, etc.) enters the
body, B lymphocytes are stimulated into
becoming rapidly dividing blast cells, which
mature into antibody-producing plasma cells.
The plasma cells are triggered by the foreign
molecule’s epitope(s) [i.e., group or groups of
specific atoms (also known as a hapten), that
are recognized to be foreign by the body’s
immune system] into producing antibody mol-
ecules possessing antigen-binding (ab) sites
(also called combining sites or determinants).
These fit into the foreign molecule’s
epitope. Thus, via the tips of its arms, the
antibody molecule binds specifically to the
foreign entity (antigen) that has entered the
body. By this process it inactivates that for-
eign molecule or marks it for eventual
destruction by other immune system cells.
System marking of the foreign molecule
(e.g., pathogen or toxin) for destruction is
accomplished by the fact that the stem of the
Y (i.e., the Fc) fragment hangs free from the
combined antibody-antigen clump, thereby
providing a receptor for phagocytes, which
roam throughout the body ingesting and sub-
sequently destroying such “marked” foreign
molecules. Research published during 2001
indicates that antibodies may also kill some
pathogens themselves by catalyzing the for-
mation of hydrogen peroxide from oxygen
free radicals (singlet oxygen) and water.
Hydrogen peroxide is highly reactive, and
could potentially kill pathogens when gen-
erated by an (attached) antibody. There are
five classes of immunoglobulin: IgG, IgM,
IgD, IgA, and IgE. See also 
HUMORAL IMMU-
NITY
,
IMMUNOGLOBULIN
,
PROTEIN
,
POLYPEPTIDE
(
PROTEIN
),
AMINO ACID
,
B LYMPHOCYTES
,
BLAST
CELL
,
ANTIGEN
,
HAPTEN
,
EPITOPE
,
COMBINING
SITE
,
DOMAIN
  (
OF A PROTEIN
),
SEQUENCE
  (
OF A
PROTEIN MOLECULE
),
ESCHERICHIA COLIFORM
(
E
.
COL I
),
PATHOGEN
,
TOXIN
,
PHAGOCYTE
,
MICROPHAGE
,
MONOCYTES
,
T CELLS
,
POLYMOR-
PHONUCLEAR LEUKOCYTES
  (
PMN
),
CELLULAR
IMMUNE RESPONSE
,
POLYMORPHONUCLEAR GRAN-
ULOCYTES
,
GENETIC ENGINEERING
, “
MAGIC BUL-
LET
”,
ENGINEERED ANTIBODIES
,
RECEPTORS
,
OXYGEN FREE RADICALS
.
Antibody Affinity Chromatography A type
of chromatography in which antibodies are
immobilized onto the column material. The
antibodies bind to their target molecules while
the other components in the solution are not
retained. In this way a separation (purifica-
tion) is achieved. See also 
ANTIBODY
,
CHROMA-
TOGRAPHY
,
AFFINITY CHROMATOGRAPHY
.
© 2002 by CRC Press LLC

A
Antibody-Mediated Immune Response S e e
HUMORAL IMMUNE RESPONSE
.
Anticoding Strand Refers to the single strand
of DNA (double helix) that is transcribed.
Sometimes called the antisense strand or the
template strand. See also 
DEOXYRIBONUCLEIC
ACID
  (
DNA
),
TRANSCRIPTION
,
ANTISENSE
  (
DNA
SEQUENCE
).
Anticodon A specific sequence of three nucle-
otides in a transfer RNA (tRNA), comple-
mentary to a codon (also three nucleotides)
for an amino acid in a messenger RNA. See
also
CODON
,
TRANSFER RNA
 (
t
RNA
),
AMINO ACID
,
MESSENGER RNA
 (
m
RNA
),
NUCLEOTIDE
.
Antigen Also called an immunogen. Any large
molecule or small organism whose entry into
the body provokes synthesis of an antibody or
immunoglobulin (i.e., an immune system
response). See also 
HAPTEN
,
ANTIBODY
,
EPITOPE
,
CELLULAR IMMUNE RESPONSE
,
HUMORAL IMMUNITY
.
Antigenic Determinant See
HAPTEN
,
EPITOPE
,
SUPERANTIGENS
.
Antihemophilic Factor VIII Also known as
Factor VIII or Antihemophilic Globulin
(AHG). See also 
FACTOR VIII
.
Antihemophilic Globulin A l s o   k n ow n   a s
Factor VIII or Antihemophilic Factor VIII.
See also 
FACTOR VIII
.
Antioxidants Compounds (e.g., phytochemi-
cals) that act to prevent lipids from oxidizing
(to plaque) or breaking down (e.g., to carci-
nogenic compounds), or that act to capture
and halt singlet oxygen (O-) free radicals;
which can damage DNA in cells (causing
mutations). Since oxidation of lipids in the
blood is the intitial step in atherosclerosis,
consumption of large amounts of certain
antioxidants (e.g., flavonoids) may prevent
atherosclerosis. Because oxidation reactions
within the body often lead to formation of
tissue-damaging free radicals (molecules
containing an “extra” electron), consump-
tion of antioxidants can help to prevent such
tissue damage. Evidence indicates that tissue
damage from free radicals may play a role
in causing some arthritis, coronary heart dis-
ease, diabetes, and cancers. Synthetic ana-
logues have also been manufactured (e.g.,
synthetic vitamins, etc.) which perform a
similar antioxidant function to naturally
occurring antioxidant phytochemicals. See
also
OXIDATIVE STRESS
,
PHYTOCHEMICALS
,
LIPIDS
,
CARCINOGEN
,
CANCER
,
ANALOGUES
,
OXI-
DATION
,
CORONARY HEART DISEASE
,
INSULIN
,
LYCOPENE
,
MUTAGEN
,
MUTATION
,
FLAVONOIDS
,
ISOFLAVONES
,
ATHEROSCLEROSIS
,
ASTAXANTHIN
,
HUMAN SUPEROXIDE DISMUTASE
 (
h
SOD
),
PEG
-
SOD
(
POLYETHYLENE GLYCOL SUPEROXIDE DISMU-
TASE
),
PLAQUE
,
PHYTATE
,
POLYPHENOLS
,
BETA
CAROTENE
,
VITAMIN E
,
POLYUNSATURATED FATTY
ACIDS
 (
PUFA
),
CONJUGATED LINOLEIC ACID
 (
CLA
).
Antiparallel Describes molecules that are par-
allel but point in opposite directions. The
strands of the DNA double helix are antipar-
allel. See also 
DOUBLE HELIX
.
Antisense (DNA sequence) A strand of DNA
that produces a messenger RNA (mRNA)
molecule which (when reversed end-for-
end) has the same sequence as (is comple-
mentary to) the unwanted (“bad”) messenger
RNA. The SENSE (forward) and ANTI-
SENSE (backward) mRNA strands hybrid-
ize (tightly bond to each other), which
prevents the bonded pair from leaving the
cell’s nucleus, so that bonded pair is rapidly
degraded (destroyed) by nuclei within the
cell nucleus. In genetic targeting (to block
“bad” genes), antisense molecules are used
to bind to a “bad” gene’s (an oncogene) mes-
senger RNA (mRNA), thus canceling the
(cancer-causing) message of the gene and
preventing cells from following its (tumor
growth) instructions. Another example
would be the use of antisense DNA to block
the gene that codes for production of poly-
galacturonase (an enzyme that causes ripe
fruit to (soften). Physically, antisense is
accomplished by removing a given gene
from an organism’s genome, reversing it
(end-for-end), and reinserting it back into the
organism’s genome. See also 
DEOXYRIBO-
NUCLEIC ACID
  (
DNA
),
CODING SEQUENCE
,
GENE
,
GENOME
,
COMPLEMENTARY DNA
  (
c
-
DNA
),
MES-
SENGER RNA
 (
m
RNA
),
GENETIC TARGETING
,
CAN-
CER
,
POLYGALACTURONASE
  (
PG
),
ONCOGENES
,
SENSE
,
COSUPPRESSION
,
GENE SILENCING
,
H Y B R I D I Z A T I O N
  (
M O L E C U L A R
G E N E T I C S
),
NUCLEASE
,
ANTICODING STRAND
.
Antisense RNA See
ANTISENSE
 (
DNA SEQUENCE
).
Antithrombogenous Polymers Synthetic poly-
mers (i.e., plastics) used to make medical
devices that will be in contact with a patient’s
© 2002 by CRC Press LLC

A
blood (e.g., catheters), but will not initiate
the coagulation process as synthetic poly-
mers usually do. The natural anticoagulant
heparin is incorporated into the polymer and
is gradually released into the bloodstream by
the polymer, thus preventing blood coagula-
tion on the surface of the polymer. See also
POLYMER
,
THROMBOSIS
.
Antitoxin See
POLYCLONAL ANTIBODIES
,
DIPH-
THERIA ANTITOXIN
.
AP Atrial peptide. See also 
ATRIAL PEPTIDES
.
APHIS The Animal and Plant Health Inspec-
tion Service is the agency of the U.S. Depart-
ment of Agriculture responsible for
regulating the field (outdoor) testing of
genetically engineered plants and certain
microorganisms. See also 
COORDINATED
FRAMEWORK FOR REGULATION OF BIOTECHNOL-
OGY
,
MICROORGANISM
,
GENETIC ENGINEERING
.
Aplastic Anemia An autoimmune disease of the
bone marrow. See also 
AUTOIMMUNE DISEASE
.
APO B-100 See
LOW
-
DENSITY LIPOPROTEINS
(
LDLP
),
APOLIPOPROTEINS
,
VERY LOW
-
DENSITY
LIPOPROTEINS
 (
VLDL
).
APO-1/Fas See
CD
95
PROTEIN
.
Apoenzyme The protein portion of a holoen-
zyme. Many (but not all) enzymes are com-
posed of functional “pieces” (i.e., a protein
piece (chain) and another piece that is an
organic and/or inorganic molecule). The
other piece is known as a cofactor, and it
may be removed from the enzyme under cer-
tain conditions, after which the resulting
inactive enzyme is known as an apoenzyme.
The inactive apoenzyme becomes function-
ally active again if it is allowed to recombine
with its cofactor. See also 
COFACTOR
,
ENZYME
,
HOLOENZYME
.