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The role of water radicals in thermorestoration of bacterial spores

Journal Article:

Abstract

Fully hydrated bacterial spores exposed to 0.45 Mrad showed a characteristic pattern of survival associated with thermorestoration. When temperature during radiation was controlled at -15/sup 0/ to +120/sup 0/C, the lowest viable cell counts were at 0/sup 0/C. Above 0/sup 0/C radiosurvival gradually increased by 2 to 3 log cycles reaching peak at 75/sup 0/C (Bacillus cereus T heat sensitive spores) and at 95/sup 0/C (B.stearothermophilus, heat resistant spores). Simultaneously high survival was observed in the solidly frozen state at -15/sup 0/C to -5/sup 0/C since harmful radicals produced by radiation were trapped in ice. Radiation modifying effects, i.e., protection by 2M ethanol (a scavenger of OH radicals) and sensitization by 1M sodium nitrate (a scavenger of H radicals and hydrated electrons), were studied. The results with ethanol and nitrate confirm the idea that in aqueous sytems below 50/sup 0/C the lethal action is due to oxidizing OH radicals known to attack cell DNA. However, the reversal of scavenger actions above 50/sup 0/C indicates that at those high temperatures lethal effects may also involve the reducing H and esub(aq), which at lower temperatures appear not to affect spore survival though they are known to attack proteins. In this case, it  More>>
Authors:
Friedman, Y S; Grecz, N [1] 
  1. Illinois Inst. of Tech., Chicago (USA). Dept. of Biology
Publication Date:
Jan 01, 1974
Product Type:
Journal Article
Reference Number:
AIX-07-242157; EDB-76-072448
Resource Relation:
Journal Name: Acta Aliment. Acad. Sci. Hung.; (Hungary); Journal Volume: 3:3; Other Information: 10 figs.; 24 refs.; 1 table
Subject:
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.; BACTERIAL SPORES; BIOLOGICAL RADIATION EFFECTS; ETHANOL; RADIOSENSITIVITY EFFECTS; NITRATES; BIOLOGICAL RECOVERY; LOW TEMPERATURE; MEDIUM TEMPERATURE; RADICALS; RADIOPROTECTIVE SUBSTANCES; RESPONSE MODIFYING FACTORS; SCAVENGING; WATER; ALCOHOLS; BIOLOGICAL EFFECTS; DRUGS; HYDROGEN COMPOUNDS; HYDROXY COMPOUNDS; NITROGEN COMPOUNDS; ORGANIC COMPOUNDS; OXYGEN COMPOUNDS; RADIATION EFFECTS; RECOVERY; SPORES; 560131* - Radiation Effects on Microorganisms- Basic Studies- (-1987)
OSTI ID:
7181869
Country of Origin:
Hungary
Language:
English
Other Identifying Numbers:
Journal ID: CODEN: AAASC
Submitting Site:
INIS
Size:
Pages: 251-265
Announcement Date:

Journal Article:

Citation Formats

Friedman, Y S, and Grecz, N. The role of water radicals in thermorestoration of bacterial spores. Hungary: N. p., 1974. Web.
Friedman, Y S, & Grecz, N. The role of water radicals in thermorestoration of bacterial spores. Hungary.
Friedman, Y S, and Grecz, N. 1974. "The role of water radicals in thermorestoration of bacterial spores." Hungary.
@misc{etde_7181869,
title = {The role of water radicals in thermorestoration of bacterial spores}
author = {Friedman, Y S, and Grecz, N}
abstractNote = {Fully hydrated bacterial spores exposed to 0.45 Mrad showed a characteristic pattern of survival associated with thermorestoration. When temperature during radiation was controlled at -15/sup 0/ to +120/sup 0/C, the lowest viable cell counts were at 0/sup 0/C. Above 0/sup 0/C radiosurvival gradually increased by 2 to 3 log cycles reaching peak at 75/sup 0/C (Bacillus cereus T heat sensitive spores) and at 95/sup 0/C (B.stearothermophilus, heat resistant spores). Simultaneously high survival was observed in the solidly frozen state at -15/sup 0/C to -5/sup 0/C since harmful radicals produced by radiation were trapped in ice. Radiation modifying effects, i.e., protection by 2M ethanol (a scavenger of OH radicals) and sensitization by 1M sodium nitrate (a scavenger of H radicals and hydrated electrons), were studied. The results with ethanol and nitrate confirm the idea that in aqueous sytems below 50/sup 0/C the lethal action is due to oxidizing OH radicals known to attack cell DNA. However, the reversal of scavenger actions above 50/sup 0/C indicates that at those high temperatures lethal effects may also involve the reducing H and esub(aq), which at lower temperatures appear not to affect spore survival though they are known to attack proteins. In this case, it is proposed that radiation inactivation of spores at temperatures below 50/sup 0/C is due to DNA damage inflicted by OH radicals whereas spore death above 50/sup 0/C seems to involve protein /enzyme/ inactivation due to a combined action of heat plus reducing (H, esub(aq)) as well as oxidizing (OH) radical species. From the practical point of view it is important that normally radioprotective effects of such substances as ethanol or ground beef are progressively lost when radiation is carried out at temperatures above 50/sup 0/C.}
journal = {Acta Aliment. Acad. Sci. Hung.; (Hungary)}
volume = {3:3}
journal type = {AC}
place = {Hungary}
year = {1974}
month = {Jan}
}