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Titolo:
INTRACELLULAR CHANGES IN IONS AND ORGANIC SOLUTES IN HALOTOLERANT BREVIBACTERIUM SP. STRAIN JCM-6894 AFTER EXPOSURE TO HYPEROSMOTIC SHOCK
Autore:
NAGATA S; ADACHI K; SANO H;
Indirizzi:
KOBE UNIV,RES INST MARINE CARGO TRANSPORTAT,HIGASHINADA KU KOBE HYOGO6580022 JAPAN MARINE BIOTECHNOL INST CO LTD SHIMIZU SHIZUOKA 424 JAPAN
Titolo Testata:
Applied and environmental microbiology (Print)
fascicolo: 10, volume: 64, anno: 1998,
pagine: 3641 - 3647
SICI:
0099-2240(1998)64:10<3641:ICIIAO>2.0.ZU;2-K
Fonte:
ISI
Lingua:
ENG
Soggetto:
COMPATIBLE SOLUTES; ESCHERICHIA-COLI; HALOPHILIC EUBACTERIA; OSMOTIC ADAPTATION; GLYCINE BETAINE; ACCUMULATION; GLUTAMATE; ECTOINE; STRESS; TETRAHYDROPYRIMIDINES;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
25
Recensione:
Indirizzi per estratti:
Citazione:
S. Nagata et al., "INTRACELLULAR CHANGES IN IONS AND ORGANIC SOLUTES IN HALOTOLERANT BREVIBACTERIUM SP. STRAIN JCM-6894 AFTER EXPOSURE TO HYPEROSMOTIC SHOCK", Applied and environmental microbiology (Print), 64(10), 1998, pp. 3641-3647

Abstract

In the present study we aimed to observe the intracellular responses when there was a hyperosmotic shock with a large shift in ionic strength in nutrient-rich and nutrient-poor external environments in order to clarify the availability of substrates. To do this, we used the halotolerant organism Brevibacterium sp. strain JCM 6894, which is able togrow in the presence of a wide range of salt concentrations. Hyperosmotic shock was induced by transferring cells in the late exponential phase of growth in a complex medium containing 0.5 M NaCl into either old or fresh culture medium containing 2 M NaCl. Changes in the growth rate, in the pH of the medium, and in the internal cation or organic solute concentrations in the cytosol after an upshock were analyzed as a function of incubation time. The cells exhibited very different responses to upshocks in fresh culture medium and in old culture medium; in fresh culture medium, growth was stimulated and the medium became more acidic, whereas the old culture medium repressed growth and the medium became more alkaline. The intracellular free Na+ concentrations remained low (80 nmol mg of protein(-1)) after an upshock in fresh culture medium, although they quickly increased twofold in the old culture medium. In contrast, K+ ions immediately accumulated in the cells in fresh culture medium, whereas K+ ions were taken up quite slowly in oldculture medium. Furthermore, the cells placed in fresh culture mediumtransiently accumulated alanine and glutamine in response to the upshock, but the cells placed in old culture medium did not. Growth of theBrevibacterium strain at higher levels of salinity was supported by ectoine synthesis but was not observed after the shift to high-osmolarity conditions in the old culture. In the fresh culture, however, ectoine was vigorously synthesized in cells for more than 5 h after the upshock; the concentration of ectoine in cells was more than 3,500 nmol mg of protein(-1) at 10 h, which corresponded to a ninefold increase compared to the concentration before the shock These findings are consistent with the results of an analysis of the extracellular medium composition before and after the upshock.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/11/20 alle ore 04:17:55