Bacteriophage Bacterium

Certain strains of Escherichia coli can be stimulated by irradiation with a moderate dose of ultraviolet (UV) light to stop normal growth and start producing bacteriophages that eventually lyse the bacterium. Bacteria of these so-called lysogenic strains carry the DNA of the phage integrated into their own... 

Autoradiography The detection of radioactive molecules (eg, DNA, RNA, protein) by visualization of their effects on photographic film. Bacteriophage A virus that infects a bacterium. Blunt-ended DNA Two strands of a DNA duplex having ends that are flush with each other. cDNA A single-stranded DNA molecule that is complementary to an mRNA molecule and is synthesized from it by the action of reverse transcriptase. 

Bacteriological sulfur, 23 577-578 Bacteriophages, 3 135 12 474 in fermentation, 11 46 Bacteriorhodopsin, 20 826, 840 photochromic material, 6 603 Bacteriosins, 12 76. See also Bacteriocins Bacteriostatic water, 18 714 Bacterium lactis, 11 7 Baculovirus expression system, 5 346 Baddeleyite, 21 489 26 623-624 colorants for ceramics, 7 346t Badische Anilin und Soda Fabrik (BASF) terpenoid manufacture process, 24 481 Baeyer-Villiger oxidation reactions, 14 592 chiral recognition by enzymes, 3 675 microbial, 16 401 Baffled shellside flow, 13 262 Baffles, in stirred tank geometries,... 

Lysozyme is an enzyme that hydrolyzes some bacterial cell-walls, the bacterium used for the assay being Micrococcus lysodeikticus. Lysozyme is found in a wide variety of species and locations, including bacteriophages, blood, egg white, gastric secretions, milk, nasal mucus, papaya, sputum, and tears. The outstanding achievement in this field has been the elucidation of the crystal structures of some of the lysozyme-substrate complexes. 

Bacteriophages Bacteriophage A has a very efficient mechanism for delivering its 48,502 bp of DNA into a bacterium, and it can be used as a vector to clone somewhat larger DNA segments (Fig. 9-6). Two key features contribute to its utility ... 

The recombinase is the A integrase (or INT protein). Integration and excision use different attachment sites and different auxiliary proteins. Excision uses the proteins XIS, encoded by the bacteriophage, and FIS, encoded by the bacterium. Both reactions require the protein IHF (/integration host /actor), encoded by the bacterium. 

Temperate bacteriophage, the best known being phage X, have a very different life cycle. Their DNA usually becomes integrated at a specific point into the genome of the bacterium (Chapter 27). Only rarely is an infected cell lysed. The retroviruses that attack mammals and birds have a similar characteristic. 

Other experiments also pointed to the conclusion that DNA was the genetic material. DNA was found localized in the nuclei of eukaryotic cells. The absolute amount per cell was constant for a given species. Studies of bacteriophage replication pointed strongly to DNA as the genetic material.11 In 1952 Hershey and Chase showed that when a phage particle infects a cell the viral DNA enters the bacterium, but the protein "coat" remains outside.13 This was demonstrated by... 

In all biological systems, gene expression is regulated so that gene products are produced either before or as they are needed. In this chapter we examine the mechanisms that ensure efficient regulation in the bacterium Escherichia coli and the bacteriophage A. 

In this chapter we discussed the regulatory systems of the E. coli bacterium and the A bacteriophage. The main points in our presentation are as follows. 

The first step in bacteriophage infection is the adsorption of the phage to a receptor on the bacterium. Almost every structure on the surface of a bacterial cell, or extending from it, can act as (or include) phage receptors (29). The 0-antigenic polysaccharide chains of the LPS are no exgeption in this respect. Since it has been estimated that 10 > to 10 LPS molecules are found on each bacterial cell (30), it is evident that part of the... 

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