Aspartic acid, one of over 20 naturally occurring amino acids.
assay A technique (test) for measuring a biological response or for determining characteristics such as composition, purity, activity,
Adenosine 5'-triphosphate; helps cells conserve and spend energy and often is used in assays of various ATP-dependent enzymes.
attenuated Weakened (attenuated) viruses often used as vaccines; they can no longer produce disease but still stimulate a strong immune
response similar to the natural virus. Examples include oral polio, measles, mumps, and rubella vaccines.
autoradiography A technique that uses X-ray film to visualize radioactively labeled molecules or molecular fragments; used in analyzing the
length and number of DNA fragments after separation by gel electrophoresis.
A Gram-positive, aerobic, endospore-forming, rod-shaped bacterium commonly found in soil, bodies of water, sewers, and in
association with some green plants; the second most common species used in recombinant fermentation; also known for its ability
to handle organic waste in other types of biotechnology such as bioremediation.
backflush Washing a column, membrane, or filter by reverse flow.
bacteriophage A virus that infects bacteria, sometimes used as a vector.
bacteriostatic agent A chemical agent that prevents microbes from multiplying but does not reliably kill them. May be used during processing,
in raw materials, or in final products, especially multiple dosage medicines.
baculovirus A virus that replicates only in the cells of Lepidopteran insects; it has been genetically engineered to force the insect
cells in culture to produce large amounts of a given protein through its natural method of replication, that is, injecting
DNA into each cell.
baseline Observations or data used for comparison or as a control.
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).
batch A quantity of a drug substance or drug product with uniform character and quality, within specified limits, produced according
to a single manufacturing run during the same cycle of manufacture.
batch culture Large-scale cell culture in which cell inoculum is cultured to a maximum density in a tank or airlift fermentor, harvested,
and processed as a batch.
benchtop A term used to distinguish between laboratory-scale or small-scale processes, those that can be performed "on the bench" (in
the lab or even on a tabletop) and larger, pilot- or production-scale processes. Bench-top equipment (a "bench-top bioreactor,"
for example) can fit on a table or in a confined laboratory area.
beta sheet (β-sheet) A structure resulting from the regular, accordion-like folding of polypeptide chains; the chief alternative to the alpha helix.
Baculovirus expression vector system, an insect cell culture method in which a genetically engineered virus transfers recombinant DNA to the insect cells it infects,
which then produce the peptide or protein in large quantities.
Blow–fill–seal, a type of fill and finish system used in the pharmaceutical industry that forms a plastic container, fills that container,
and then seals it with in-line machinery.
Baby hamster kidney cells, an established mammalian cell line that is commonly used for biotechnology.
bioactivity A protein's ability to function correctly after it has been delivered to the active site of the body (in vivo).