| bacteriophage t4 | <microbiology> A bacteriophage (a virus which infects bacteria) which uses DNA as its genetic material (some viruses use RNA) and is unusually large. (09 Oct 1997) |
|---|---|
| bacteriophage t7 | <microbiology> A bacteriophage (a virus which infects bacteria) that is useful to geneticists because it has a very strong promoter region which strongly encourages transcription of its gene by specific T7 RNA polymerase. Geneticists can take the part with the promoter and attach their own genes of interest to it so that they can control transcription rates of their gene by choosing the amount of the RNA polymerase to put in. (09 Oct 1997) |
| bacteriophage T7 induced DNA polymerase | <enzyme> Complex of two proteins, phage gene 5 protein and E coli thioredoxin Registry number: EC 2.7.7.- Synonym: t7 phage DNA polymerase, sequenase, t7 DNA polymerase, thermo sequenase (26 Jun 1999) |
| bacteriophage typing | A technique of bacterial typing which differentiates between bacteria or strains of bacteria by their susceptibility to one or more bacteriophages. (12 Dec 1998) |
| R17 bacteriophage | Bacteriophage with RNA genome that codes for the enzyme RNA synthetase and for the coat protein, a protein to which the RNA is attached and that is involved in attachment to the bacterium. (18 Nov 1997) |
| vegetative bacteriophage | The form of bacteriophage in which the bacteriophage nucleic acid (lacking its coat) multiplies freely within the host bacterium, independently of bacterial multiplication. (05 Mar 2000) |
| mature bacteriophage | The complete, infective form of bacteriophage. (05 Mar 2000) |
| virulent bacteriophage | A bacteriophage that regularly causes lysis of the bacteria that it infects; it may exist in one or the other of only two forms, vegetative or mature; it does not have a probacteriophage form (i.e., its genome does not incorporate with that of the host bacterium), therefore it does not effect lysogenization. (05 Mar 2000) |
| defective bacteriophage | A temperate bacteriophage mutant whose genome does not contain all of the normal components and cannot become fully infectious virus, yet can replicate indefinitely in the bacterial genome as defective probacteriophage; many defective bacteriophage's are mediators of transduction. Synonym: defective phage. (05 Mar 2000) |
| temperate bacteriophage | Bacteriophage whose genome incorporates with, and replicates with, that of the host bacterium; dissociation (and resultant development of vegetative bacteriophage) occurs at a slow rate resulting occasionally in lysis of a bacterium and release of mature bacteriophage, thus rendering the bacterial culture capable of inducing general lysis if transferred to a culture of a susceptible bacterial strain. (05 Mar 2000) |
| typhoid bacteriophage | Bacteriophage specific for Salmonella typhi. (05 Mar 2000) |
| filamentous bacteriophage | <molecular biology> A type of single-stranded DNA bacteriophage (virus which infects bacteria) that has a capsid which is long and thin, like a filament. Examples include the viruses F1 and M13. (10 Mar 1998) |
| lambda bacteriophage | <virology> Bacterial DNA virus, first isolated from E. Coli. Its structure is similar to that of the T even phages. Lambda genetic material consists of a double-stranded DNA molecule with 5' twelve-base-pair sticky ends, known as cos sites, which permit circularisation of the DNA molecule. It shows a lytic cycle and a lysogenic cycle and studies on the control of these alternative cycles have been very important for our understanding of the regulation of gene transcription. It is used as a cloning vector, accommodating fragments of DNA up to 15 kilobase pairs long. For larger pieces, the cosmid vector was constructed from its ends. (14 Mar 2000) |
| lysosogenic bacteriophage | <virology> Bacteriophage that can take part in a lysogenic or lytic cycle in its bacterial host. See: lysogeny. (15 Oct 1997) |
| acquired immunity | <immunology> A form of cellular defense which identifies certain foreign substances (antigens) as harmful to the body. For this reason, the body can acquire resistance to a particular foreign agent. These foreign agents are then attacked by sensitised T lymphocytes (cellular immunity). White blood cells, plasma cells, B lymphocytes and other specialised immune system cells act in concert with T lymphocytes to produce antibodies (humoral immunity) that attach to the antigen directing T-cells to attack. Antibodies also stimulate the release of special chemical mediators in the blood (for example complement, interferon) that further enhance antigen destruction. (13 Nov 1997) |