Biomaterial Database

Effect of phosphate buffer agar on the number of UV-induced mutations to streptomycin resistance in Escherichia coli strains. 1990

S M Specht, and A S Sideropoulos

Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania 15282.

The number of UV-induced mutations to streptomycin resistance in Escherichia coli B/r cells depends on the post-irradiation incubation medium. When cells are incubated on phosphate buffer agar (PBA) as opposed to brain heart infusion agar (BHI), there is an irreversible loss in the number of potential streptomycin resistant mutants which develop. This decrease in mutant numbers is known to occur without a corresponding loss in overall cell viability and cannot be explained in terms of the kinetics of dimer excision. Recent studies have indicated that pyrimidine dimers are the substrate for this repair on PBA. The genetics of PBA repair was investigated by observing the influence of the post-irradiation incubation medium (PBA vs BHI) on the number of streptomycin resistant mutants which develop in E. coli strains deficient in various repair pathways. A recB and recC strain (WP3 recB trp-; WP7 recC trp-) showed repair of potential streptomycin resistant mutants similar to that of B/r when incubated on PBA following irradiation. The medium had no effect on the number of mutants expressed in an excision deficient uvrA- strain (WP2 uvrA trp-) or a polymerase I mutant (P3478 polA thy-). This was interpreted to mean that the loss of streptomycin resistant mutants on PBA involves the excision repair pathway and is dependent on the polA gene product, polymerase I.

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
D010710	Phosphates	Inorganic salts of phosphoric acid.	Inorganic Phosphate,Phosphates, Inorganic,Inorganic Phosphates,Orthophosphate,Phosphate,Phosphate, Inorganic
D003470	Culture Media	Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.	Media, Culture
D004256	DNA Polymerase I	A DNA-dependent DNA polymerase characterized in prokaryotes and may be present in higher organisms. It has both 3'-5' and 5'-3' exonuclease activity, but cannot use native double-stranded DNA as template-primer. It is not inhibited by sulfhydryl reagents and is active in both DNA synthesis and repair.	DNA Polymerase alpha,DNA-Dependent DNA Polymerase I,Klenow Fragment,DNA Pol I,DNA Dependent DNA Polymerase I,Polymerase alpha, DNA
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
D004352	Drug Resistance, Microbial	The ability of microorganisms, especially bacteria, to resist or to become tolerant to chemotherapeutic agents, antimicrobial agents, or antibiotics. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).	Antibiotic Resistance,Antibiotic Resistance, Microbial,Antimicrobial Resistance, Drug,Antimicrobial Drug Resistance,Antimicrobial Drug Resistances,Antimicrobial Resistances, Drug,Drug Antimicrobial Resistance,Drug Antimicrobial Resistances,Drug Resistances, Microbial,Resistance, Antibiotic,Resistance, Drug Antimicrobial,Resistances, Drug Antimicrobial
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
D013307	Streptomycin	An antibiotic produced by the soil actinomycete Streptomyces griseus. It acts by inhibiting the initiation and elongation processes during protein synthesis.	Estreptomicina CEPA,Estreptomicina Clariana,Estreptomicina Normon,Strepto-Fatol,Strepto-Hefa,Streptomycin Grünenthal,Streptomycin Sulfate,Streptomycin Sulfate (2:3) Salt,Streptomycin Sulphate,Streptomycine Panpharma,Strepto Fatol,Strepto Hefa
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