Biomaterial Database

Radiation protection of E. coli strains by cysteamine in the presence of oxygen. 1986

J W Hülsewede, and D Schulte-Frohlinde

The survival of various E. coli K12 strains with defects in the rec system have been measured after gamma-irradiation in air in the presence (0.1 mol dm-3) or in the absence of cysteamine. The results confirm those of Bresler et al. (1978) indicating that the protection by cysteamine in the presence of oxygen is due to an influence on enzymatic repair. The low protection by cysteamine of wild-type cells pretreated with chloramphenicol which prevents protein synthesis, supports the above conclusion. The reason for the absence of a protective effect by OH radical scavenging and H-atom donation is discussed. It is proposed that DNA peroxyl radicals are formed during irradiation in the presence of oxygen and that they are transformed into hydroperoxides by H-atom donation from the intracellular glutathione and the added cysteamine. These hydroperoxides are still dangerous for the cell as indicated by the protective action of glutathione peroxidase observed by Marklund et al. (1984).

UI	MeSH Term	Description	Entries
D010100	Oxygen	An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.	Dioxygen,Oxygen-16,Oxygen 16
D003543	Cysteamine	A mercaptoethylamine compound that is endogenously derived from the COENZYME A degradative pathway. The fact that cysteamine is readily transported into LYSOSOMES where it reacts with CYSTINE to form cysteine-cysteamine disulfide and CYSTEINE has led to its use in CYSTINE DEPLETING AGENTS for the treatment of CYSTINOSIS.	Cysteinamine,Mercaptamine,2-Aminoethanethiol,Becaptan,Cystagon,Cysteamine Bitartrate,Cysteamine Dihydrochloride,Cysteamine Hydrobromide,Cysteamine Hydrochloride,Cysteamine Maleate (1:1),Cysteamine Tartrate,Cysteamine Tartrate (1:1),Cysteamine Tosylate,Cysteamine, 35S-Labeled,Mercamine,Mercaptoethylamine,beta-Mercaptoethylamine,2 Aminoethanethiol,35S-Labeled Cysteamine,Bitartrate, Cysteamine,Cysteamine, 35S Labeled,Dihydrochloride, Cysteamine,Hydrobromide, Cysteamine,Hydrochloride, Cysteamine,Tartrate, Cysteamine,Tosylate, Cysteamine,beta Mercaptoethylamine
D004247	DNA	A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).	DNA, Double-Stranded,Deoxyribonucleic Acid,ds-DNA,DNA, Double Stranded,Double-Stranded DNA,ds DNA
D004249	DNA Damage	Injuries to DNA that introduce deviations from its normal, intact structure and which may, if left unrepaired, result in a MUTATION or a block of DNA REPLICATION. These deviations may be caused by physical or chemical agents and occur by natural or unnatural, introduced circumstances. They include the introduction of illegitimate bases during replication or by deamination or other modification of bases; the loss of a base from the DNA backbone leaving an abasic site; single-strand breaks; double strand breaks; and intrastrand (PYRIMIDINE DIMERS) or interstrand crosslinking. Damage can often be repaired (DNA REPAIR). If the damage is extensive, it can induce APOPTOSIS.	DNA Injury,DNA Lesion,DNA Lesions,Genotoxic Stress,Stress, Genotoxic,Injury, DNA,DNA Injuries
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
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
D006878	Hydroxides	Inorganic compounds that contain the OH- group.
D017665	Hydroxyl Radical	The univalent radical OH. Hydroxyl radical is a potent oxidizing agent.