These transgenic goats are being milked by a special machine.
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roller bottle A container with large growth surfaces in which cells can be grown in a confluent monolayer. The bottles are rotated or agitated
to keep cells in contact with growth media, but they require extensive handling, labor, and media. In large-scale vaccine
production, roller bottles have been replaced by microcarrier culture systems that offer the advantage of scale-up, minimizing
contamination.
R subgroup (or side chain) The group of atoms that differs among different amino acid molecules and thus determines their diverse chemical properties;
for example, the R subgroup on a Gly molecule is simply a hydrogen atom, on an Ala it is a methyl complex (a carbon atom and three hydrogens),
and on Glu it is a combination of carbon, oxygen, nitrogen, and hydrogen atoms.
S
Saccharomyces cerevisiae
Brewer's yeast, familiar to cooks as the yeast used to leaven bread, was the first and is still the most widely used yeast
species in biotechnology. Certain strains are used in the manufacture of alcoholic beverages and fermented foods — and also
for expression of genes. Biologically active interferons, for example, have been produced in it and it can be used in the
manufacture of biologics. Commonly Abbreviated: S. cerevisiae.
scale-down To model a biopharmaceutical manufacturing process (or section of that process) at the laboratory scale, usually for validation
or other study purposes. Scale-down requires holding the critical parameters constant, and may be confounded by differences
in equipment dead volumes, per-formance, materials of construction.
Many vendors sell turnkey systems like this chromatography–filtration unit.
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scale-up To transfer a biopharmaceutical manufacturing process from the laboratory scale to a manufacturing scale while holding critical
parameters constant.
Schizosaccharomyces pombe
The second most commonly used yeast species in biotechnology, originally used in east Africa to brew millet beer but which
is typically unsuitable for other types of fermentation because of the large amount of sulfurous compounds it emits.
SDS
Sodium dodecyl sulfate, an ionic detergent that binds to and denatures proteins, and binds in rough proportion to the size of the protein; used to
aid analytical separations.
SDS-PAGE
Sodium dodecyl sulfate–polyacrylamide gel electrophoresis; the SDS detergent denatures and binds to proteins, aiding in their separation. Analytical separation technique, often used to characterize
proteins or mixtures, that uses a charged gel environment through which molecules of varying sizes and electric charges migrate
from one pole to the other. Unlike gel-filtration chromatography, larger molecules move more slowly than smaller molecules
because migration rate is not dependent on diffusion into and out of particles.
SEC
Size-exclusion chromatography, gel-filtration or gel-permeation chromatography; an analytical method that uses porous particles to separate molecules of
different sizes. Molecules that are smaller than the pore size can enter the particles and therefore have a longer path and
longer transit time than larger molecules that cannot enter the particles. SEC can separate biological molecules and help
scientists determine the molecular weights and molecular weight distributions of polymers.
secondary structure In proteins, the folding, twisting, coiled, sometimes spring-like chain that results when hydrogen bonds form between the
adjacent parts of a molecule, as in an alpha helix or beta sheet.
seed stock The initial inoculum, or the cells placed in growth medium from which other cells will grow.
sequence The precise order of bases in a nucleic acid or amino acids in a protein.
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