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Titolo:
AMINO-ACID EFFLUX IN RESPONSE TO CHEMOTACTIC AND OSMOTIC SIGNALS IN BACILLUS-SUBTILIS
Autore:
WONG LS; JOHNSON MS; SANDBERG LB; TAYLOR BL;
Indirizzi:
LOMA LINDA UNIV,DEPT MICROBIOL & MOLEC GENET LOMA LINDA CA 92350 LOMA LINDA UNIV,DEPT MICROBIOL & MOLEC GENET LOMA LINDA CA 92350
Titolo Testata:
Journal of bacteriology
fascicolo: 15, volume: 177, anno: 1995,
pagine: 4342 - 4349
SICI:
0021-9193(1995)177:15<4342:AEIRTC>2.0.ZU;2-R
Fonte:
ISI
Lingua:
ENG
Soggetto:
ESCHERICHIA-COLI; SENSORY ADAPTATION; GLUTAMIC-ACID; PROTEINS; METHYLATION; SHOCK; ATTRACTANTS; OSMOLYTES; TREHALOSE; TRANSIENT;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
38
Recensione:
Indirizzi per estratti:
Citazione:
L.S. Wong et al., "AMINO-ACID EFFLUX IN RESPONSE TO CHEMOTACTIC AND OSMOTIC SIGNALS IN BACILLUS-SUBTILIS", Journal of bacteriology, 177(15), 1995, pp. 4342-4349

Abstract

We observed a large efflux of nonvolatile radioactivity from Bacillussubtilis in response to the addition of 31 mM butyrate or the withdrawal of 0.1 M aspartate in a flow assay. The major nonvolatile components effluxed were methionine, proline, histidine, and lysine, In studies of the release of volatile radioactivity in chemotaxis by B. subtilis cells that had been labeled with [H-3] methionine, the breakdown of methionine to methanethiol can contribute substantially to the volatile radioactivity in fractions following addition of 0.1 M aspartate. However, methanol was confirmed to be released after aspartate addition and, in lesser quantities, after aspartate withdrawal. Methanol and methanethiol were positively identified by derivitization with 3,5-dinitro-benzoylchloride. Amino acid efflux but not methanol release was observed in response to 0.1 M aspartate stimulation of a cheR mutant of B. subtilis that lacks the chemotaxis methylesterase, The amino acid efflux could be reproduced by withdrawal of 0.1 M NaCl, 0.2 M sucrose, or 0.2 M xylitol and is probably the result of changes in osmolarity. Chemotaxis to 10 mM alanine or 10 mM proline resulted in methanol release but not efflux of amino acids. In behavioral studies, B. subtilis tumbled for 16 to 18 s in response to a 200 mosM upshift and for 14 s after a 20 mosM downshift in osmolarity when the bacteria were in perfusion buffer (40 mosM). The pattern of methanol release was similar to that observed in chemotaxis. This is consistent with osmotaxis in B. subtilis away from an increase or decrease in the osmolarity of the incubation medium. The release of methanol suggests that osmotaxis is correlated with methylation of a methyl-accepting chemotaxis protein.

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Documento generato il 01/10/20 alle ore 06:07:42