Biomaterial Database

Dark recovery processes in Escherichia coli irradiated with ultraviolet light. I. Effect of rec mutations on liquid holding recovery. 1968

A K Ganesan, and K C Smith

We have examined various derivatives of Escherichia coli K-12 for liquid holding recovery, a type of recovery originally observed in E. coli B irradiated with ultraviolet light. Although most of the K-12 derivatives tested showed relatively little or no recovery under our conditions, four of the six independent rec(-) mutants examined, those carrying recA1, rec-12, recA13, and rec-56, respectively, displayed marked recovery. These mutants are distinguished from rec(+) strains by their increased sensitivity to ultraviolet radiation and decreased ability to undergo genetic recombination. Two of them have also been reported to release large amounts of their deoxyribonucleic acid as acid-soluble material, especially after irradiation. None of the three uvr(-) mutants examined, containing uvrA6, uvrB5, or uvrC34, showed comparable liquid holding recovery. The one rec(-) uvr(-) derivative tested, carrying recA13 and uvrA6, did not appear to undergo liquid holding recovery, although recA13 uvr(+) strains did. Genetic analysis of one strain, a recA13 mutant, indicated that all the rec(+) derivatives obtained from it by conjugation, transduction and reversion, had lost the property of showing liquid holding recovery. From these results, we conclude that in E. coli K-12 the expression of liquid holding recovery depends upon certain rec(-) mutations.

UI	MeSH Term	Description	Entries
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
D011831	Radiation Genetics	A subdiscipline of genetics that studies RADIATION EFFECTS on the components and processes of biological inheritance.	Genetics, Radiation
D011995	Recombination, Genetic	Production of new arrangements of DNA by various mechanisms such as assortment and segregation, CROSSING OVER; GENE CONVERSION; GENETIC TRANSFORMATION; GENETIC CONJUGATION; GENETIC TRANSDUCTION; or mixed infection of viruses.	Genetic Recombination,Recombination,Genetic Recombinations,Recombinations,Recombinations, Genetic
D003227	Conjugation, Genetic	A parasexual process in BACTERIA; ALGAE; FUNGI; and ciliate EUKARYOTA for achieving exchange of chromosome material during fusion of two cells. In bacteria, this is a uni-directional transfer of genetic material; in protozoa it is a bi-directional exchange. In algae and fungi, it is a form of sexual reproduction, with the union of male and female gametes.	Bacterial Conjugation,Conjugation, Bacterial,Genetic Conjugation
D003624	Darkness	The absence of light.	Darknesses
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
D005796	Genes	A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.	Cistron,Gene,Genetic Materials,Cistrons,Genetic Material,Material, Genetic,Materials, Genetic
D005827	Genetics, Microbial	A subdiscipline of genetics which deals with the genetic mechanisms and processes of microorganisms.	Microbial Genetics,Genetic, Microbial,Microbial Genetic
D014161	Transduction, Genetic	The transfer of bacterial DNA by phages from an infected bacterium to another bacterium. This also refers to the transfer of genes into eukaryotic cells by viruses. This naturally occurring process is routinely employed as a GENE TRANSFER TECHNIQUE.	Genetic Transduction,Genetic Transductions,Transductions, Genetic
D014466	Ultraviolet Rays	That portion of the electromagnetic spectrum immediately below the visible range and extending into the x-ray frequencies. The longer wavelengths (near-UV or biotic or vital rays) are necessary for the endogenous synthesis of vitamin D and are also called antirachitic rays; the shorter, ionizing wavelengths (far-UV or abiotic or extravital rays) are viricidal, bactericidal, mutagenic, and carcinogenic and are used as disinfectants.	Actinic Rays,Black Light, Ultraviolet,UV Light,UV Radiation,Ultra-Violet Rays,Ultraviolet Light,Ultraviolet Radiation,Actinic Ray,Light, UV,Light, Ultraviolet,Radiation, UV,Radiation, Ultraviolet,Ray, Actinic,Ray, Ultra-Violet,Ray, Ultraviolet,Ultra Violet Rays,Ultra-Violet Ray,Ultraviolet Black Light,Ultraviolet Black Lights,Ultraviolet Radiations,Ultraviolet Ray