ISSN:
1433-4909
Keywords:
Key words Sucrose transport
;
Alkaliphile
;
Thermophile
;
Sodium gradient
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract An alkaliphilic Bacillus designated strain TA2.A1, isolated from a thermal spring in Te Aroha, New Zealand, grew optimally at pH 9.2 and 70°C. Sodium chloride (〉5 mM) was an obligate requirement for the growth of strain TA2.A1 on sucrose, and growth on sucrose was inhibited by monensin, an ionophore that collapses the sodium gradient (ΔpNa+) across the cell membrane. Sucrose transport by strain TA2.A1 was sodium dependent and was inhibited by monensin. The Kt for sucrose tran-sport was 33 μM and the Eadie–Hofstee plot was linear, suggesting one high-affinity uptake system for sucrose. The affinity for sodium was low (0.5 mM), and the Hill plot had a slope of 1.6, suggesting that sodium binding was noncooperative and that the sucrose transporter had more than one binding site for sodium. Based on these results, Bacillus strain TA2.A1 uses a sodium gradient for sucrose uptake, in addition to the sodium-dependent glutamate uptake system reported previously.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s007920070016
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