Biomaterial Database

Physiological effects of growth of an Escherichia coli temperature-sensitive dnaZ mutant at nonpermissive temperatures. 1977

H Chu, and M M Malone, and W G Haldenwang, and J R Walker

The physiological effects of incubation at nonpermissive temperatures of Escherichia coli mutants that carry a temperature-sensitive dnaZ allele [dnaZ(Ts)2016] were examined. The temperature at which the dnaZ(Ts) protein becomes inactivated in vivo was investigated by measurements of deoxyribonucleic acid (DNA) synthesis at temperatures intermediate between permissive and nonpermissive. DNA synthesis inhibition was reversible by reducing the temperature of cultures from 42 to 30 degrees C; DNA synthesis resumed immediately after temperature reduction and occurred even in the presence of chloramphenicol. Inasmuch as DNA synthesis could be resumed in the absence of protein synthesis, we concluded that the protein product of the dnaZ allele (Ts)2016 is renaturable. Cell division, also inhibited by 42 degrees C incubation, resumed after temperature reduction, but the length of time required for resumption depended on the duration of the period at 42 degrees C. Replicative synthesis of cellular DNA, examined in vitro in toluene-permeabilized cells, was temperature sensitive. Excision repair of ultraviolet light-induced DNA lesions was partially inhibited in dnaZ(Ts) cells at 42 degrees C. The dnaZ(+) product participated in the synthesis of both Okazaki piece (8-12S) and high-molecular-weight DNA. During incubation of dnaZ(Ts)(lambda) lysogens at 42 degrees C, prophage induction occurred, and progeny phage were produced during subsequent incubation at 30 degrees C. The temperature sensitivity of both DNA synthesis and cell division in the dnaZ(Ts)2016 mutant was suppressed by high concentrations of sucrose, lactose, or NaCl. Incubation at 42 degrees C was neither mutagenic nor antimutagenic for the dnaZ(Ts) mutant.

UI	MeSH Term	Description	Entries
D008242	Lysogeny	The phenomenon by which a temperate phage incorporates itself into the DNA of a bacterial host, establishing a kind of symbiotic relation between PROPHAGE and bacterium which results in the perpetuation of the prophage in all the descendants of the bacterium. Upon induction (VIRUS ACTIVATION) by various agents, such as ultraviolet radiation, the phage is released, which then becomes virulent and lyses the bacterium.	Integration, Prophage,Prophage Integration,Integrations, Prophage,Prophage Integrations
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D009997	Osmotic Pressure	The pressure required to prevent the passage of solvent through a semipermeable membrane that separates a pure solvent from a solution of the solvent and solute or that separates different concentrations of a solution. It is proportional to the osmolality of the solution.	Osmotic Shock,Hypertonic Shock,Hypertonic Stress,Hypotonic Shock,Hypotonic Stress,Osmotic Stress,Hypertonic Shocks,Hypertonic Stresses,Hypotonic Shocks,Hypotonic Stresses,Osmotic Pressures,Osmotic Shocks,Osmotic Stresses,Pressure, Osmotic,Pressures, Osmotic,Shock, Hypertonic,Shock, Hypotonic,Shock, Osmotic,Shocks, Hypertonic,Shocks, Hypotonic,Shocks, Osmotic,Stress, Hypertonic,Stress, Hypotonic,Stress, Osmotic,Stresses, Hypertonic,Stresses, Hypotonic,Stresses, Osmotic
D002455	Cell Division	The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION.	M Phase,Cell Division Phase,Cell Divisions,Division Phase, Cell,Division, Cell,Divisions, Cell,M Phases,Phase, Cell Division,Phase, M,Phases, M
D002701	Chloramphenicol	An antibiotic first isolated from cultures of Streptomyces venequelae in 1947 but now produced synthetically. It has a relatively simple structure and was the first broad-spectrum antibiotic to be discovered. It acts by interfering with bacterial protein synthesis and is mainly bacteriostatic. (From Martindale, The Extra Pharmacopoeia, 29th ed, p106)	Cloranfenicol,Kloramfenikol,Levomycetin,Amphenicol,Amphenicols,Chlornitromycin,Chlorocid,Chloromycetin,Detreomycin,Ophthochlor,Syntomycin
D004260	DNA Repair	The removal of DNA LESIONS and/or restoration of intact DNA strands without BASE PAIR MISMATCHES, intrastrand or interstrand crosslinks, or discontinuities in the DNA sugar-phosphate backbones.	DNA Damage Response
D004269	DNA, Bacterial	Deoxyribonucleic acid that makes up the genetic material of bacteria.	Bacterial DNA
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D000483	Alleles	Variant forms of the same gene, occupying the same locus on homologous CHROMOSOMES, and governing the variants in production of the same gene product.	Allelomorphs,Allele,Allelomorph
D013696	Temperature	The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.	Temperatures