The effects of oxygen availability on the rate of growth and on RNA and protein metabolism in Rhodotorula gracilis
Abstract
Data di Pubblicazione:
1972
Citazione:
The effects of oxygen availability on the rate of growth and on RNA and protein metabolism in Rhodotorula gracilis / M. Cocucci, S.M. Cocucci. - In: INFORMATORE BOTANICO ITALIANO. - ISSN 0020-0697. - 4:1(1972), pp. 73-73. (Intervento presentato al convegno Congresso della Società Italiana di Fisiologia Vegetale tenutosi a Bologna nel 1972).
Abstract:
The present work deals with the effects of low oxygen availability on the rate of growth
and of RNA and protein synthesis in Rhodotorula gracilis cells growing in a liquid mineralglucose
medium. In these experiments O2 partial pressure in tl.!e medium has been measured
and maintained satisfactorily constant by means of a Clark oxygen electrode. It has been found
that: a) the optimal rate of growth requires O2 partial pressure above 3 mm of Hg; b) lowering
O2 pressure below this value induces a progressive inhibition of growth; c) under conditions
of suboptimal O2 availability (ca. 1 ±0.2 mm Hg) the accumulation of RNA and DNA is
inhibited in an earlier period and to larger extent than protein synthesis. Experiments of
incorporation of 32p orthophosphate into RNA show that the « low O2 » condition is characterized
by a marked inhibition of RNA synthesis, even in the case of relatively short 'pulses' (5 minutes),
while no important changes of the rate RNA breakdown is observed. In fact, the rate of 32p
incorporation into RNA remains practically linear in time for at least 30 minutes. This behaviour
is in contrast with the one observed in this yeast as a consequence of nitrogen or of glucose
starvation; in these cases the block of the net synthesis of RNA appears to correspond rather
to an increased rate of breakdown of the newly formed RNA than to an inhibition at transcription
level.
Tipologia IRIS:
01 - Articolo su periodico
Elenco autori:
M. Cocucci, S.M. Cocucci
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