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 to that sample.
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.
aggregate A clustered mass of individual cells solid, fluffy, or pelletized that can clog the pores of filters or other fermentation apparatus.
amino acids A class of 20 hydrocarbon molecules that combine to form proteins in living things.
anaerobe An anaerobic organism grows in the absence of air or oxygen. Some anaerobic organisms are killed by brief exposure to oxygen, whereas oxygen may just retard or stop the growth of others.
antibody An infection-fighting protein molecule that tags, neutralizes, and helps destroy foreign microorganisms or toxins. Also known as immunoglobulins , antibodies are produced by the immune system in response to antigens, which are often bacterial or viral particles or components.
antifoam agent A chemical added to the fermentation broth to reduce surface tension and counteract the foaming (bubbles) that can be caused by mixing, sparging, or stirring.
antigen (antigenicity) Any agent, often a large molecule, that stimulates production of an antibody that will react specifically with it. Each antigen may contain more than one site capable of binding to a particular antibody. An immunogen can cause the production of a number of antibodies with different specificities. Antigenicity is the capacity of a substance to function as an antigen to trigger an immune response.
artificial chromosome Synthesized DNA in chromosomal form for use as an expression vector.
aseptic Sterile, free from bacteria, viruses, and contaminants such as foreign DNA.
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.
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). .
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.
bioactivity A proteins 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.
biologic A therapeutic agent derived from living things.
biopharmaceutical A therapeutic product created through the genetic manipulation of living things, including (but not limited to) proteins and monoclonal antibodies, peptides, and other molecules that are not chemically synthesized, along with gene therapies, cell therapies, and engineered tissues.
bioprocessing Using organisms or biologically derived macromolecules to carry out enzymatic reactions or to manufacture products.
bioreactor A vessel capable of supporting a cell culture in which a biological transformation takes place (also called a fermentor or reactor).
broth The contents of a microbial bioreactor: cells, nutrients, waste, and so on.
cascade effects A series of events that result from one initial cause.
catabolites Waste products of catabolism , by which organisms convert substances into excreted compounds.
cell culture Cells taken from a living organism and grown under controlled conditions (in culture). Methods used to maintain cell lines or strains.
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.
chemostat A growth chamber that keeps a bacterial culture at a specific volume and rate of growth by limiting nutrient medium and removing spent culture.
chromosome A long and complex DNA chain containing the genetic information (genes) of a cell. Prokaryotes contain only a single chromosome; eukaryotes have more than one, made up of a complex of DNA, RNA, and protein. The exact number of chromosomes is species-specific. Humans have 23 pairs.
CIP (clean in place) A way to clean large vessels (tanks, piping, and associated equipment) without moving them or taking them apart, using a highpressure rinsing treatment, sometimes followed by steam-in-place (SIP) sanitization.
clean room A room in which the concentration of airborne particulate matter is controlled at specific limits to facilitate the manufacture of sterile and high-purity products. Clean rooms are classified according to the number of particles per volume of air.
clearance Demonstrated removal according to specified parameters.
clone To duplicate exactly, whether a gene or a whole organism; or an organism that is a genetically identical copy of another organism.
cloning vectors Methods of transferring desired genes to organisms that will be used to express them. Cloning vectors are used to make recombinant organisms.
cosmid An artificially constructed plasmid vector that contains a specific bacteriophage gene, which allows it to carry up to 45,000 base pairs of desired DNA.
Creutzfeld-Jacob disease A disease affecting the human nervous system, believed to be caused by a prion that also causes bovine spongiform encephalopathy (BSE) or Mad Cow Disease in cattle.
cryopreservation Maintenance of frozen cells, usually in liquid nitrogen.
cytokine A protein that acts as a chemical messenger to stimulate cell migration, usually toward where the protein was released. Interleukins, lym phokines, and interferons are the most common.
cytopathic Damaging to cells, causing them to exhibit signs of disease.
cytoplasm The protoplasm of a cell outside the nucleus (inside the nucleus is it called nucleoplasm ). Protoplasm is a semifluid, viscous, translucent mixture of water, proteins, lipids, carbohydrates, and inorganic salts found in all plant and animal cells.
cytostat Something that retards cellular activity and production. This can refer to cytostatic agents or to machinery, such as those that would freeze cells.
dalton The unit of molecular weight, equal to the weight of a hydrogen atom.
downstream processing Bioprocessing steps following fermentation and/or cell culture, a sequence of separation and purification activities needed to obtain the required drug product at the necessary level of purity.
DNA (deoxyribonucleic acid) The nucleic acid based on deoxyribose (a sugar) and the nucleotides G, A, T, and C. Occurring in a corkscrew-ladder shape, it is the primary component of chromosomes, which thus carry inheritable charac teristics of life.
DNA fingerprinting Sequences of nucleic acids in specific areas (loci) on a DNA molecule are polymorphic , meaning that the genes in those locations may differ from person to person. DNA fragments can be cut from those sequences using restriction enzymes. Fragments from various samples can be analyzed to determine whether they are from the same person. The technique of analyzing restriction fragment length polymorphism (RFLP) is called DNA typing or DNA fingerprinting.
DNA vaccine A nucleic acid vaccine: Genes coding for specific antigenic proteins are injected to produce those antigens and trigger an immune response.
efficacy The ability of a substance (such as a protein therapeutic) to pro duce a desired clinical effect; its strength and effectiveness.
ELISA Enzyme linked immunosorbent assay: a test to measure the concen tration of antigens or antibodies.
endogenous Growing or developing from a cell or organism, or arising from causes within the organism.
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, and it is involved in detoxifying chemicals such as drugs and pesticides.
endotoxin A poison in the form of a a fat/sugar complex (lipopolysaccha ride) that forms a part of the cell wall of some types of bacteria. It is released only when the cell is ruptured and can cause septic shock and tissue dam age. Pharmaceuticals are tested routinely for endotoxins.
enzymes Proteins that catalyze biochemical reactions by causing or speed ing up reactions without being changed in the process themselves.
epithelium (epithelial) The layer(s) of cells between an organism or its tissues or organs and their environment (skin cells, inner linings of lungs or digestive organs, outer linings of kidneys, and so on).
eukaryotes Complex organisms, often multicellular, whose cells contain nuclei.
exogenous Developing from outside, originating externally. Exogenous fac tors can be external factors such as food and light that affect an organism.
express To translate a cells 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 recombinant organism that will express the desired protein.
fermentor A bioreactor used to grow bacteria or yeasts in liquid culture.
floc A fluffy aggregate that resembles a woolly cloud.
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. The nonproduct fusion partner is left over and usually thrown away.
gene The unit of inheritance consisting of a sequence of DNA, occupying specific position within the genome. Three types of genes have been identified: structural genes encoding particular proteins; regulatory genes controlling the expression of the other genes; and genes for transfer RNA or ribosomal RNA instead of proteins.
genetic engineering Altering the genetic structure of an organism (adding foreign genes, removing native genes, or both) through technological means rather than traditional breeding.
genotype The genetic composition of an organism (including expressed and nonexpressed genes), which may not be readily apparent.
germ cell The sex cells in higher animals and plants that carry only half of the organisms genetic material and can combine to develop into new living things.
glycosylation Adding one or more carbohydrate molecules onto a protein (a glycoprotein) after it has been built by the ribosome; a posttranslational modifi cation.
GMPs Good manufacturing practices required by FDA regulations.
Golgi body A cell organelle consisting of stacked membranes where post translational modifications of proteins are performed; also called Golgi appara tus.
growth hormone A protein produced in the pituitary gland to control cell growth.
hemocytometer A device for counting blood cells.
hormone A protein released by an endocrine gland to travel in the blood and act on tissues at another location in the body.
HPLC High-performance liquid chromatography or high-pressure liquid chromatography, a commonly used method for separating liquid mixtures.
hybridoma An immortalized cell line (usually derived by fusing B-lympho cyte cells with myeloma tumor cells) that secretes desirable antibodies.
immortalize To alter cells (either chemically or genetically) so that they can reproduce indefinitely.
inoculate To introduce cells into a culture medium.
inoculum Material (usually cells) introduced into a culture medium.
interferon A cytokine that inhibits virus reproduction. Interferons also affect growth and development (differentiation) in certain normal and tumor cells.
in vitro Performed in the laboratory rather than in a living organism (in vivo).
ligase An enzyme that causes fragments of DNA or RNA to link together; used with restriction enzymes to create recombinant DNA.
lymphocytes White blood cells that produce antibodies.
lysosomes Cell organelles containing enzymes, responsible for degrading proteins and other materials ingested by the cell.
MAb Monoclonal antibody: A highly specific, purified antibody that recog nizes only a single antigen.
macrokinetics Movement of whole cells and their media within a bioreactor.
media A (usually sterile) preparation made for the growth, storage, mainte nance, or transport of microorganisms or other cells.
metabolites Chemical byproducts of metabolism , the chemical process of life.
microbiology The study of microscopic life such as bacteria, viruses, and yeast.
microcarrier A microscopic particle (often, a 200-m polymer bead) that supports cell attachment and growth in suspension culture.
microencapsulated Surrounded by a thin, protective layer of biodegrad able substance referred to as a microsphere.
microheterogeneity Slight differences in the amino acid sequence of a protein. For example, to produce a recombinant protein in E. coli , a methion ine (met) must be added to one end of the protein sequence to act as a sig nal that initiates protein synthesis. In most cases, that met is removed once the protein is made. Sometimes the met is removed for only some of the mol ecules. The purified product is then a mixture of a protein with the native sequence and a protein with the native sequence plus the extra amino acid.
microinjection Manually using tiny needles to inject microscopic material (such as DNA) directly into cells or cell nuclei; computer screens provide a mag nified view.
microkinetics Movement of chemicals into, out of, and within the cell.
microorganism A microbe; a living thing too small to be seen by the naked eye.
microtubules Cellular organelles common in microorganisms: thin tubes that make structures involved in cellular movement.
mitochondria Animal-cell organelles that reproduce using their own DNA. They metabolize nutrients to provide the cell with energy and are believed to have once been symbiotic bacteria. Chloroplasts are their plant-cell equiva lents.
multicellular Referring to organisms composed of more than one cell often billions of them, arranged in various organs, tissues, and systems.
mutagen An agent (chemicals, radiation) that causes mutations in DNA.
mutation A permanent change in DNA sequence or chromosomal struc ture.
mycoplasma parasitic microorganisms that infect mammals, possessing some characteristics of both bacteria and viruses.
myeloma Lymphocytic cancer; a malignancy normally found in bone mar row.
nucleic acids DNA or RNA: long, chainlike molecules composed of nucleotides.
nucleotides Molecules composed of a nitrogen-rich base, phosphoric acid, and a sugar. The bases can be adenine (A), cytosine (C), guanine (G), thymine (T), or uracil (U).
nucleus The largest organelle, a sphere that contains all the cells genetic material and a nucleolus that builds ribosomes.
oncogene A gene that, when expressed as a protein, can lead cells to become cancerous, usually by removing the normal constraints on its growth.
organelle A structurally discrete component that performs a certain func tion inside a eukaryotic cell.
organism A single, autonomous living thing. Bacteria and yeasts are organ isms; mammalian and insect cells used in culture are not.
PCR Polymerase chain reaction, a method of duplicating genes exponential ly.
peptides Proteins consisting of fewer than 40 amino acids.
phenotype The part of an organisms genotype that is expressed, and thus is generally apparent by observation.
pilot plant A medium-scale bioprocessing facility used as an intermediate in scaling up processes from the laboratory to commercial production.
plasmid Hereditary material that is not part of a chromosome. Plasmids are circular and self-replicating and found in the cytoplasm of cells (naturally in bacteria and some yeasts). They can be used as vectors for introducing up to 10,000 base-pairs of foreign DNA into recipient cells.
polymerase An enzyme that catalyzes the production of nucleic acid mole cules.
posttranslational modifications Protein processing done by the Golgi bodies after proteins have been constructed by ribosomes.
prions Resembling viruses, these pathogens are composed only of protein, with no detectable nucleic acid.
prokaryotes Simple organisms with no cell nuclei and very few cell organelles.
protein Macromolecules whose structures are coded in an organisms DNA. Each is a chain of more than 40 amino acids folded back upon itself in a partic ular way.
proteolytic Capable of lysing (denaturing, or breaking down) proteins.
recombinant Containing genetic material from another organism. Genetically altered microorganisms are usually referred to as recombinant, whereas plants and animals so modified are called transgenic (see transgen ics).
restriction enzyme An bacterial enzyme that cuts DNA molecules at the location of particular sequences of base pairs.
ribosome Cell organelles that translate RNA to build proteins.
RNA Ribonucleic acid; similar to DNA but based on ribose, and with the base uracil (U) in place of thymine (T). Various forms of RNA are found: mRNA (messenger RNA); tRNA (transfer RNA); and rRNA (ribosomal RNA). Most RNA molecules are single-stranded, although they can form double-stranded units.
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 suspension, but they require extensive handling, labor, and media. In large-scale vaccine production, roller bottles have been replaced by microcar rier culture systems that offer the advantage of scale-up.
scale-up To take a biopharmaceutical manufacturing process from the labo ratory scale to a scale at which it is commercially feasible.
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.
serum The watery portion of an animal or plant fluid (such as blood) remain ing after coagulation. When cheese is made, whey is the milk serum thats left.
SIP Steam in place or sterilize in place (see CIP).
somatic cell In higher organisms, a cell that (unlike germ cells) carries the full genetic make-up of an organism.
sparge To spray. A sparger is the component of a fermentor that sprays air into the broth.
strain A population of cells all descended from a single cell.
substrate Reactive material, the substance on which an enzyme acts.
substratum The solid surface of which a cell moves or on which cells grow.
supernatant Material floating on the surface of a liquid mixture (often the liquid component that has the lowest density).
surfactant Any substance that changes the nature of a surface, such as lowering the surface tension of water.
suspension Particles floating in (not necessarily on) a liquid medium, or the mix of particles and liquid itself.
symbiotic Living together for mutual benefit.
synthesis Creating products through chemical and enzymatic reactions.
tissue culture Growing plant or animal tissues outside of the body, as in nutrient medium in a laboratory; similar to cell culture, but cells are maintained in their structured, tissue form.
titer A measured sample. (To draw a measured, representative sample from a larger amount is to titrate .)
transgenics The alteration of plant or animal DNA so that it contains a gene from another organism. There are two types of cells in animals and plants, germ line cells (the sperm and egg in animals, pollen and ovule in plants) and somatic cells (all of the other cells). It is the germ-line DNA that is altered in transgenic animals and plants, so those alterations are passed on to off spring. Transgenic animals are used to produce therapeutics, to study dis ease, or to improve livestock strains. Transgenic plants have been created for increased resistance to disease and insects as well as to make biopharma ceuticals.
translation The process by which information transferred from DNA by RNA specifies the sequence of amino acids in a polypeptide (protein) chain.
trypsin, tryptic digestion Trypsin allows the growth of cells as indepen dent microorganisms distinct from tissue culture by causing cell disaggrega tion. Excised tissue is softened and treated with a proteolytic enzyme, normally trypsin, then washed and suspended in a growth medium to produce a prima ry culture. Subculturing from the primary culture usually involves treatment with an antitrypsin (such as serum) to produce a secondary culture. Cell lines are established by repeated culture through cycles of growth, trypsinization, and subculture. Trypsin is also used to remove anchorage-dependent cells from their attached substratum.
tryptic fragment analysis Quantitating the resultant fragments caused by tryptic digestion.
turbidostat A variation on a chemostat. Whereas a chemostat is designed for constant input of medium, a turbidostat is designed to keep the organisms at a constant concentration. A turbidity sensor measures the concentration of organisms in the culture and adds additional medium when a preset value is exceeded.
turbulent flow field The state that results from mixing the contents of a fermentor or bioreactor to provide oxygen to the cells. That must be balanced against the shear that causes cell damage and death.
unicellular Composed of only a single cell.
vaccines Preparations of antigens from killed or modified organisms that elicit immune response (production of antibodies) to protect a person or ani mal from the disease-causing agent.
vacuolation In cell and tissue culture, excess fluid, debris (aggregates), or gas (from sparging) can form inside a cell vacuole. A vacuole is a cavity within the cell that can be relatively clear and fluid filled, gas filled (as in a number of blue-green algae), or food filled (as in protozoa).
vector The plasmid, virus, or other vehicle used to carry a DNA sequence into the cell of another species.
vessel jacket A temperature control method consisting of a double wall out side the main vessel wall. Liquid or steam flows through the jacket to heat (or cool) the fluid in the vessel. Because biopharmaceutical products are so sensi tive and vessel jackets can cause uneven heating (hot or cold spots), shell-and tube or plate-and-frame heat exchangers are more common in biopharmaceuti cal production systems.
viability Life and health, ability to grow and reproduce; a measure of the proportion of live cells in a population.
virus The simplest form of life: RNA or DNA wrapped in a shell of protein, sometimes with a means of injecting that genetic material into a host organ ism (infection). Viruses cannot reproduce on their own, but require the aid of host.
viscosity Thickness of a liquid; determines its internal resistance to shear forces.
water-for-injection Very pure water suitable for medical uses.
yeast A single-celled fungus.