Details

Autor(en) / Beteiligte

• Rajkhowa, R.C
• Goswami, P
• Singh, H.D

Titel

Mode of uptake of sterol by Arthrobacter simplex

Ist Teil von

• World journal of microbiology & biotechnology, 2000-02, Vol.16 (1), p.63-68

Ort / Verlag

Dordrecht: Springer

Erscheinungsjahr

2000

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The mechanism of uptake of water-insoluble β-sitosterol by a newly isolated strain of Arthrobacter simplex SS-7 was studied. The production of an extracellular sterol-pseudosolubilizing protein during growth of A. simplex on β-sitosterol was demonstrated by isolating the factor from the cell-free supernatant and its subsequent purification by Sephadex G-150 column chromatography. The M^sub r^ of the purified sterol-pseudosolubilizing protein determined by SDS-PAGE was 19kDa. The rate of sterol pseudosolubilization (5.2×10^sup -3^g l^sup -1^h^sup -1^) could not adequately account for the rate of sterol uptake (72×10^sup -3^g l^sup -1^h^sup -1^) and the specific growth rate (56×10^sup -3^ h^sup -1^). However in the unfavourable growth condition, when the cells were treated with sodium azide at the level of 30-60% of MIC, the sterol pseudosolubilization accounted for nearly 74% of the total growth containing 96% free cells. Cellular adherence to substrate particles was found to play an active role in the normal growth of the strain on β-sitosterol. Unlike sodium acetate-grown cells, whose surface activity was negligible (60mNm^sup -1^), the sterol-grown cells had strong surface activity (40mNm^sup -1^). The high lipid content and long chain fatty acids in the cell-wall of β-sitosterol-grown cells probably contribute to the high sterol adherence activity of the cells.[PUBLICATION ABSTRACT]