Glossary

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A
Adjuvant

Any substance which, when administered with or before an antigen, heightens and/or affects qualitatively the immune response in terms of antibody formation and/or the cell-mediated response.

Aerobe

A micro-organism that grows in the presence of oxygen.

Agonist

A drug, hormone or transmitter substance that forms a complex with a receptor site that is capable of triggering an active response from a cell.

Amino acid

Any of 20 basic building blocks of proteins with a free amino (NH2) and a free carboxyl (COOH) group, and having the basic formula NH2 - CR - COOH. According to the side group R, they are subdivided into: polar or hydrophilic (serine, threonine, tyrosine, asparagine and glutamine); non-polar or hydrophobic (glycine, alanine, valine, leucine, isoleucine, proline, phenylalanine, tryptophan and cysteine); acidic (aspartic acid and glutamic acid) and basics (lysine, arginine, hystidine). The sequence of amino acids determines the shape, properties and the biological role of a protein. Plants and many micro-organisms can synthesize amino acids from simple inorganic compounds, but animals are unable to synthesize some of them, called essential amino acids, so they must be present in the diet.

Anaerobe

An organism that can grow in the absence of oxygen.

Antibiotic

A class of natural and synthetic compounds that inhibit the growth of or kill some micro-organisms. 

Antibody

An immunological protein produced by certain white blood cells of the immune system of an organism in response to a contact with an antigen. Such an immunological protein has the ability of specifically binding with the foreign substance and rendering it harmless.

Antigen

A compound that elicits an immune response by stimulating the production of antibodies. 

Attenuated vaccine

A virulent organism that has been modified to produce a less virulent form, but nevertheless retains the ability to elicit antibodies against the virulent form.

B
Bacterin

A vaccine containing killed bacterial cells.

Bacteriostat

A substance that inhibits or slows down growth and reproduction of bacteria.

Biosafety level 1

(BSL-1) is the basic level of protection and is appropriate for agents that are not known to cause disease in normal, healthy humans. 

Biosafety level 2

(BSL-2) is appropriate for handling moderate-risk agents that cause human disease of varying severity by ingestion or through percutaneous or mucous membrane exposure. 

Biosafety level 3

(BSL-3) is appropriate for agents with a known potential for aerosol transmission, for agents that may cause serious and potentially lethal infections and that are indigenous or exotic in origin. 

Biosafety level 4

(BSL-4) is appropriate for exotic agents that pose a high individual risk of life-threatening disease by infectious aerosols and for which no treatment is available.

C
Carcinogen

A substance capable of inducing cancer in an organism.

D
DNA

(deoxyribonucleic acid)  The long chain of molecules in most cells that carries the genetic message and controls all cellular functions in most forms of life. The information-carrying genetic material that comprises the genes.

E
Efficacy (vaccine)

A measure of the specific protective capacity of the biologic when used according to label recommendations.

Endemic

Describing a disease or a pest that is always present in an area.

Enzyme

A protein produced in living cells, which, even in very low concentration, catalyses specific chemical reactions but is not used up in the reaction. 

Epitope

A specific chemical domain on an antigen that stimulates the production of, and is recognized by, an antibody. 

F
Fermentation

The anaerobic breakdown by micro-organisms of complex organic substances, especially carbohydrates like glucose. 

Fungicide

An agent, such as a chemical, that kills fungi.

G
Generation time

The time that it takes for a population of single-celled organisms to double its cell number. Successive generations of cells or organisms within a population are separated by a time interval called generation time. 

Genotype

The genetic constitution (gene makeup) of an organism.

H
Heterologous

From a different source.

Histology

Science that deals with the microscopic structure of animal tissues.

Homologous

From the same source, or having the same evolutionary function or structure.

I
Immunity

The state of relative insusceptibility of an animal to infection by disease-producing organisms or to the harmful effects of their poisons.

Infection

The invasion of any living organisms by disease-causing micro-organisms, which proceed to establish themselves, multiply, and produce various clinical signs in their host.

Interferon

A family of small proteins that stimulate viral resistance in cells.

K
Kauffmann–White classification

A scheme for the classification and identification of the numerous serotypes of Salmonella (e.g. for epidemiological purposes). Each serotype is defined by its O Antigens and, where applicable, its H Antigens and VI Antigens, and is given a specific Antigenic formula which indicates the nature of these antigens in the order O, Vi (if present) : H phase 1 : H phase 2. 

 

 

L
LD50 (lethal dose 50%)

The amount of a chemical required to kill 50% of the test population. The higher the LD50, the lower the presumed toxicity of the chemical.

M
Mycotoxin

Toxic substance of fungal origin, such as aflatoxin.

N
Necrosis

 Death associated with discoloration and dehydration of all or some parts of organs.

O
Oncogene

A gene that causes cells to grow in an uncontrolled manner. Oncogenes are mutant forms of normal functional genes (called proto-oncogenes) that have a role in normal cell proliferation.

Organ

A tissue or group of tissues that constitute a morphologically and functionally distinct part of an organism.

P
Parts per million (ppm)

Units of any given substance per one million equivalent units.

Persistence

Ability of an organism to remain in a particular setting for a period of time after it is introduced.

pH

A measure of acidity and alkalinity.

Polyacrylamide Gel Electrophoresis (PAGE)

A method for separating nucleic acid or protein molecules according to their molecular size. 

Polymerase Chain Reaction (PCR)

A procedure that amplifies a particular DNA sequence.

Polypeptide

A linear molecule composed of two or more amino acids linked by covalent (peptide) bonds. 

Potency (vaccine)

A measure of the relative strength of a biologic when tested by established methods which are documented in the production outline. It should correlate with the immunogenicity/efficacy of the biologic.

Purity (of a final biological product)

The quality or condition of being free from extraneous micro-organisms and substances as determined by established test methods.

Pyrethrins

Active constituents of pyrethrum (Tanacetum cinerariifolium) flowers, used as insecticides.

Q
Quinolone antibiotics

A group of synthetic antibiotics whose targets are gyrase (gyrase-targeted antibiotics), and topoisomerase IV; each antibiotic contains a substituted 4-quinolone ring.

S
Safety (vaccine)

The freedom from properties causing undue local or systemic reactions, when used as recommended.

Supernatant

The soluble liquid fraction of a sample after centrifugation or precipitation of insoluble solids.

T
Tissue culture

Culture of cells, tissues or organs in a nutrient medium under sterile conditions.

Toxin

A compound produced by an organism and poisonous to plants or animals.

V
Vaccine

A preparation of inactivated or attenuated pathogens, or of derived antigenic determinants, that is used to induce formation of antibodies or immunity against the pathogen.

Virus

An infectious particle composed of a protein capsule and a nucleic acid core (DNA or RNA), which is dependent on a host organism for replication.

Y
Yeast

A unicellular ascomycete fungus, commonly found as a contaminant in plant tissue culture.