Glossary

Mar 10, 2006
By BioPharm International Editors

Many of these terms have more general definitions as well. Those given here are specific to their application in cell culture and fermentation.

absorption Removing a particular antibody or antigen from a sample (from serum, for example) by adding the corresponding antigen or antibody.

adsorption Nonspecific adherence of substances in solution or suspension to cells or other particulate matter.

adventitious agents Acquired, sporadic, accidental contaminants.

aerobe An aerobic organism is one that grows in the presence of oxygen. A strict aerobe grows only under such a condition.

antigen An agent, often a large molecule, that stimulates production of an antibody that will react specifically with it.

bacteriophage A virus that infects bacteria, sometimes used as a vector.

base pair Two bases on different strands of nucleic acid that join together. In DNA, cytosine (C) always pairs with guanine (G) and adenine (A) always links to thymine (T). In RNA molecules, adenine joins to uracil (U).

bioactivity A protein's ability to function correctly after it has been delivered to the active site of the body (in vivo).

bioavailability Measure of the true rate and the total amount of drug that reaches the target tissue after administration.

cell lines When cells from the first culture (taken from the organism) are used to make subsequent cultures, a cell line is established. Thanks to genetic or other manipulations, immortal cell lines can replicate indefinitely.

cloning vectors Methods of transferring desired genes to organisms that will be used to express them. Cloning vectors are used to make recombinant organisms.

cytokine A protein that acts as a chemical messenger to stimulate cell migration, usually toward where the protein was released. Interleukins, lymphokines, and interferons are the most common.

cytopathic Damaging to cells, causing them to exhibit signs of disease.

DNA fingerprinting Sequences of nucleic acids in specific areas on a DNA molecule are polymorphic, meaning that genes in those locations may differ from person to person. DNA fragments can be cut from those sequences using restriction enzymes.

DNA vaccine A nucleic acid vaccine: Genes coding for specific antigenic proteins are injected to produce those antigens and trigger an immune response.

endonuclease A restriction enzyme that breaks up nucleic acid molecules at specific sites along their length. Such enzymes are naturally produced by microorganisms as a defense against foreign nucleic acids.

endoplasmic reticulum A highly specialized and complex network of branching, interconnecting tubules (surrounded by membranes) found in the cytoplasm of most animal and plant cells. The rough endoplasmic reticulum is where ribosomes make proteins. It appears "rough" because it is covered with ribosomes. The smooth endoplasmic reticulum is the site for synthesis and metabolism of lipids.

eukaryotes Complex organisms, often multicellular, whose cells contain nuclei.

express To translate a cell's genetic information, stored in its DNA (gene), into a specific protein.

expression system Organisms chosen to manufacture (by expression) a protein of interest through recombinant DNA technology.

expression vector A way of delivering foreign genes to a host, creating a recombinant organism that will express the desired protein.

fusion partner When making a small protein or peptide in E. coli, it is often necessary to produce the protein fused to a larger protein to get high levels of stable expression. The resulting fusion protein must be cleaved (chemically or enzymatically broken) to yield the desired protein or peptide.

genotype The genetic composition of an organism (including expressed and nonexpressed genes), which may not be readily apparent.