Glossary of Bacterial Gentics
A
Allele
any of one or more alternative forms of a gene
Amino acid
organic nitrogenous acids from which protein molecules are constructed
B
Bacteriocin
a protein antibiotic, one or more types of which can be produced and
excreted by certain strains of bacteria
Bacteriophage
a virus that infects a bacterium
Bacterium (pl. bacteria)
a prokaryotic, microscopic, single-celled organism with a cell wall that
increases by binary fission
Biotechnology
the development of genetically modified organisms through the use of
modern technology and processes, including genetic engineering
Biotype
a subdivision of a species, subspecies, or race based on some identifiable
physiological trait such as a specific virulence pattern
C
Chromosome
the structure that contains the genes of an organism; in eukaryotes,
chromosomes are in the nucleus and can be visualized with an optical
microscope as threads or rods during meiosis and mitosis; in bacteria, the
chromosome is usually a single circle of DNA that cannot be visualized with
an optical microscope
Codon
a particular sequence of three nucleotides in a nucleic acid that codes for a
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specific amino acid or termination of a polypeptide chain (see triplet
codon)
Conjugation
the temporary contact of bacterial cells during which genetic material is
transferred
D
Deoxyribonucleicacid (abbr. DNA)
the double-stranded, helical molecule that contains genetic code
information; each repeating unit, or nucleotide, is composed of
deoxyribose (a sugar), a phosphate group, and a purine (adenine or
guanine) or a pyrimidine (thymine or cytosine) base.
G
Gene
unit within an organism controlling heritable characteristics;
genes are organized on chromosomes
Genome
the complete genetic information of an organism or virus
Genotype
genetic constitution of an individual or group; class or group of
individuals sharing a specific genetic makeup (see phenotype)
Genus (pl. genera)
a taxonomic category that includes a group of closely related
(structurally or phylogenetically) species; the genus or generic
name is the first name in a Latin binomial
M
Messenger RNA (abbrev. mRNA)
a form of RNA that carries information to direct the synthesis
of protein.
Mutation (n. mutant)
an abrupt heritable or genetic change in a gene or an
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individual as a result of an alteration in a gene or
chromosome, or of an increase in chromosome number.
N
Negative-sense RNA (-RNA)
ribonucleic acid complementary to the positive or plus sense;
not translated into protein (contrasts with positive-sense RNA)
Nucleic acid
genetic material of all living organisms, including DNA
(deoxyribonucleic acid) and RNA (ribonucleic acid)
Nucleoid
region in prokaryotes, chloroplasts, and mitochondria where
the DNA is concentrated. Unlike a nucleus, it is not bound by a
membrane.
Nucleus
dense aggregation of proteinaceous matter and nucleic acid in
cells, surrounded by a membrane; contains chromosomes and
controls heredity
Nucleotide
a subunit of a nucleic acid, either DNA or RNA
O
Open reading frame
portion of a nucleic acid molecule that is translated into a
protein.
P
PCR (acronym for polymerase chain reaction)
a technique used to amplify the number of copies of a specific
region of DNA in order to produce enough of the DNA for use
in various applications such as identification and cloning
Plasmid
a circular, self-replicating hereditary element that is not part
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of a chromosome; plasmids are used in recombinant DNA
experiments as acceptors and vectors of foreign DNA
Positive-sense RNA (+RNA)
RNA that can serve directly as messenger RNA (contrasts with
negative-sense RNA).
Primer
small fragment of nucleic acid with a free 3'-hydroxyl group
necessary for initiation of DNA and, sometimes, RNA
synthesis; often specific fragments chosen for use in
polymerase chain reaction (PCR) for rapid identification of
pathogens
pv. (abbrev. for pathovar)
a subdivision of a plant pathogenic bacterial species defined
by host range; pathovar for bacteria is equivalent to forma
specialis for fungi.
R
Race
subgroup or biotype within a species or variety, distinguished
from other races by virulence, symptom expression, or host
range, but not by morphology
Recombinant DNA
DNA molecules in which sequences, not normally contiguous,
have been placed next to each other by in vitro methods
Replication
the process by which a DNA or RNA molecule makes an exact
copy of itself;
repetition of an experiment or procedure at the same time
and place (one of several identical experiments, procedures,
or samples);
the process by which a virus particle induces the host cell to
reproduce the virus
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Restriction endonuclease
enzyme that cleaves DNA at a particular base sequence;
sometimes informally referred to as a restriction enzyme
Reverse transcriptase
enzyme used to make complementary DNA from a piece of
RNA, such as a plant virus genome
Ribosomal RNA (abbrev. rRNA)
RNA molecules forming part of the ribosomal structure.
Ribosome
a subcellular protoplasmic particle, made up of one or more
RNA molecules and several proteins, involved in protein
synthesis.
RNA (acronym for ribonucleic acid)
several nucleic acids composed of repeating units of ribose (a
sugar), a phosphate group, and a purine (adenine or guanine)
or a pyrimidine (uracil or cytosine) base; transcribed from DNA
and involved in translation to proteins.
rRNA (abbrev. for ribosomal RNA)
RNA molecules forming part of the ribosomal structure.
S
Species
any one kind of life subordinate to a genus but above a race; a
group of closely related individuals of the same ancestry,
resembling one another in certain inherited characteristics of
structure and behavior and relative stability in nature; the
individuals of a species ordinarily interbreed freely and
maintain themselves and their characteristics in nature.
T
Transduction
the transfer of genes from one organism to another by viruses,
especially in bacteria.
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Transfer RNA (abbrev. tRNA)
the RNA that moves amino acids to the ribosome to be placed
in the order prescribed by the messenger RNA.
Transformation
the transfer of genetic materials from one organism to
another by humans (genetic engineering); a means of genetic
variation in bacteria by absorption and incorporation of DNA
from another bacterial cell.
Transgenic
possessing a gene from another species; used to describe the
organisms that have been the subject of genetic engineering
(see also genetically modified organism, GMO).
Translation
the assembling of amino acids into a protein using messenger
RNA, ribosomes and transfer RNA.
Triplet codon
a set of three nucleotide bases in DNA or RNA that code for an
amino acid.
Type
the example on which the description of a scientific name is
based, and which fixes the application of the name (the type
genus of a family, or the type species of a genus).
American Phytopathological Society (APS)
Illustrated Glossary of Plant Pathology
Authors: C.J. D'Arcy, D.M. Eastburn, and G. L. Schumann
(with acknowledgement of contributions from M.C. Shurtleff, P.A.
Arneson, F.H. Tainter, and T.A. Evans)
http://www.apsnet.org/edcenter/illglossary/Pages/default.aspx
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