Biomaterial Database

Changes in the ultraviolet sensitivity of Escherichia coli during growth in batch cultures. 1969

R A Morton, and R H Haynes

The ultraviolet (UV) sensitivity of Escherichia coli B/r harvested at various times during growth in batch cultures was measured. The results showed a period of increased UV sensitivity in late log phase, just before the cultures entered stationary phase. This increase in sensitivity was associated with a decreased shoulder in the UV survival curves. The postirradiation division delay of survivors was shortest for cells harvested during the period of maximal sensitivity. This period of increased UV sensitivity during late log phase was not found in the radiation-sensitive, repair-deficient mutant B(s-1) (a strain which is unable to excise pyrimidine dimers from UV-damaged deoxyribonucleic acid). These results suggest that the variation in UV sensitivity of E. coli B/r as a function of time of harvesting of the cells from batch cultures is related to the varying capacities of these populations to repair UV-damaged deoxyribonucleic acid. Further experiments designed to elucidate the mechanism underlying this variation in UV sensitivity indicated that it arises from the partial depletion of nutrients in the medium during late log phase. We suggest that growth in such depleted media leads to a depression in the intercellular concentration or activity of one or more of the repair enzymes concerned with the repair of damaged deoxyribonucleic acid.

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
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
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
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