Data di Pubblicazione:
1973
Citazione:
Rhodotorula gracilis : adaptation of the mithocondrial apparatus to shortage of oxygen / G. Rossi, M. Cocucci. - In: INFORMATORE BOTANICO ITALIANO. - ISSN 0020-0697. - 5:1(1973), pp. 114-114. (Intervento presentato al 13. convegno Congresso della Società Italiana di Fisiologia Vegetale tenutosi a Gran Sasso).
Abstract:
Oxygen is known to induce the synthesis, in fermenting yeasts, of oxidating enzymes
and of the whole mitochondrial apparatus in general. The mitochondrial apparatus is, on the
other hand, reduced under conditions of shortage of oxygen.
Previous experiments had shown that Rhodotorula gracilis maintains an extraordinary
metabolic activity even at very low (1-3 mm Hg in the culture medium) partial pressures of
oxygen, thus indicating the existence of systems capable of utilizing oxygen which have a
great affinity for it.
EM observations of cells grown at low oxygen concentrations (about 1 mm Hg) show
a well defined increase of the system of mitochondrial membranes as against control cells
grown under aerobic conditions. At slightly higher oxygen concentrations (2 mm Hg) there
is no indication of significant changes in the mitochondrial system.
Spectrophotometric analysis of whole yeast cells shows that at 1 mm Hg of oxygen partial
pressure alterations occur in the peaks of absorption specific for cytochromes as measured both
as absolute and as differential (ox-red)absorbancy.
As cellular synthetic activities are strongly inhibited under these conditions, the results
so far obtained seem to suggest that cytoplasmic growth is likely to be much more sensitive
to oxygen shortage than the mitochondrial one. Similarly, the observed discrepancy between
mitochondrial and cytoplasmic volumes seems to be related to a stronger repression of cytoplasmic
synthetic processes rather than to a stimulation of mitochondrial syntheses
Tipologia IRIS:
01 - Articolo su periodico
Elenco autori:
G. Rossi, M. Cocucci
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