Biomaterial Database

The fate of thymine-containing dimers in ultraviolet-irradiated Halobacterium cutirubrum. 1987

P S Fitt, and N Sharma

Department of Biochemistry, University of Ottawa, Canada.

Extremely halophilic bacteria do not recover in the dark from the effects of ultraviolet radiation, although they can be completely photoreactivated, thus proving that pyrimidine dimers are the cytotoxic photoproducts. We have now shown, by studying the fate of thymine-containing dimers during dark liquid-holding of Halobacterium cutirubrum, that the lack of dark repair in these bacteria is due to their inability to excise such lesions, in contrast to Escherichia coli B. Nevertheless, extensive nonspecific degradation of DNA occurs in H. cutirubrum following ultraviolet irradiation, so the lack of dimer excision is not due to a generalised inability to degrade DNA after such treatment. These findings raise interesting questions concerning the basis of the resistance of halophiles to ultraviolet radiation.

UI	MeSH Term	Description	Entries
D011740	Pyrimidine Dimers	Dimers found in DNA chains damaged by ULTRAVIOLET RAYS. They consist of two adjacent PYRIMIDINE NUCLEOTIDES, usually THYMINE nucleotides, in which the pyrimidine residues are covalently joined by a cyclobutane ring. These dimers block DNA REPLICATION.	Cyclobutane Pyrimidine Dimer,Cyclobutane-Pyrimidine Dimer,Cytosine-Thymine Dimer,Pyrimidine Dimer,Thymine Dimer,Thymine Dimers,Cyclobutane-Pyrimidine Dimers,Cytosine-Thymine Dimers,Thymine-Cyclobutane Dimer,Thymine-Thymine Cyclobutane Dimer,Cyclobutane Dimer, Thymine-Thymine,Cyclobutane Dimers, Thymine-Thymine,Cyclobutane Pyrimidine Dimers,Cytosine Thymine Dimer,Cytosine Thymine Dimers,Pyrimidine Dimer, Cyclobutane,Pyrimidine Dimers, Cyclobutane,Thymine Cyclobutane Dimer,Thymine Thymine Cyclobutane Dimer,Thymine-Cyclobutane Dimers,Thymine-Thymine Cyclobutane Dimers
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
D004307	Dose-Response Relationship, Radiation	The relationship between the dose of administered radiation and the response of the organism or tissue to the radiation.	Dose Response Relationship, Radiation,Dose-Response Relationships, Radiation,Radiation Dose-Response Relationship,Radiation Dose-Response Relationships,Relationship, Radiation Dose-Response,Relationships, Radiation Dose-Response
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
D006217	Halobacterium	A genus of HALOBACTERIACEAE whose growth requires a high concentration of salt. Binary fission is by constriction.
D013045	Species Specificity	The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.	Species Specificities,Specificities, Species,Specificity, Species
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