Change in transport activities of vacuoles of the yeast Yarrowia lipolytica during its growth on glucose

Abstract

Vacuoles were isolated from Yarrowia lipolytica yeast cells taken at various growth phases under carbon or nitrogen limitation. Vacuoles from the cells at the logarithmic growth phase showed a high activity of vacuolar H(+)-ATPase (0.9-1.1 U/mg protein) and efficiently generated chemical proton gradient and membrane potential across the tonoplast. Ca(2+)- and citrate transport were found to be maximal at this growth phase. At growth retardation and then in the stationary phase all the parameters studied decreased irrespective of the method of growth limitation. The citrate-transporting activity of vacuoles completely disappeared at growth retardation, also irrespective of the limitation method and irrespective of whether yeast cells overproduced citrate in the culture medium. The citrate-transporting system of Y. lipolytica vacuolar membrane is concluded not to be involved in citrate efflux and this efflux is probably performed by the plasmalemma transport system.

Aluminum impairs morphogenic transition and stimulates H+transport mediated by the plasma membrane ATPase ofYarrowia lipolytica

“…Y. lipolytica resistance in response to Al treatment could be related to organic acid exudation, a process described in plants ( Kochian et al, 2004;Shen et al, 2005). Yarrowia lipolytica is known for its capacity to produce organic acids (Barth & Gaillardin, 1997) and citrate efflux was suggested to be performed by a plasma membrane transport system rather than by vacuole (Kulakovskaya et al, 1993). It would be interesting to determine whether organic acid secretion is induced in Al-treated Y. lipolytica cells.…”