ON THE CYTOCHROMES OF ANAEROBICALLY 

 CULTURED YEAST 



By Paulette Chaix 



Laboratoire de Cliimie biologiqiie de la Faculte des Sciences, 

 Paris 



The first observations of cytochrome spectra, made at ordinary temperature 

 by MacMunn between 1884 and 1886 and by Keilin in 1925, led to the con- 

 clusion that cells grown anaerobically are lacking in these pigments. This 

 point of view appeared later to be confirmed and the term cytochrome, 

 notably because of the intra-mitochondrial localization (Chance and Williams, 

 1955, 1956) of the components {a + ^3), b, c^ and c of aerobic cells, became 

 synonymous with oxidation-reduction catalysts belonging to the respiratory 

 chain. 



At the present time, it is known that certain anaerobic cells (Postgate, 

 1954a, 1954b; Ephrussi and Slonimski, 1950) and certain cellular fractions 

 lacking respiratory activity (Strittmatter and Ball, 1954; Chance and 

 Williams, 1954) of anaerobic organisms may contain spectrographically 

 detectable oxidation-reduction enzymes of haematin type, and the problem 

 arises of trying to distinguish without ambiguity the cytochromes which 

 belong to the respiratory chain from those which do not. 



Bakers' yeast, which may be cultured aerobically or strictly anaerobically, 

 appeared to us a particularly suitable material to elucidate such problems as 

 these. This work has been done in collaboration with Therese Heyman- 

 Blanchet and Francois Zajdela, with the aid of the spectrographic method for 

 studying the cytochromes in situ at room temperature (Chaix and Fromageot, 

 1942) and subsequently adapted to low temperature measurements (Chaix 

 and Petit, 1956, 1957). 



VARIATIONS OF THE HAEMATIN SPECTRUM OF YEAST 



CULTURED ANAEROBICALLY, AS A FUNCTION OF ITS 



GROWTH PHASES 



Saccharomyces cerevisiae ('yeast foam' diploid) may be cultivated under strict 

 anaerobiosis at 25°C either on a Difco yeast extract medium or on a synthetic 

 medium. By adding to these two media Tween 80 and ergosterol, as recom- 

 mended by Andreasen and Stier (1953, 1954) growth rates of // = 0-65 and 

 ^ = 0-45 respectively (Heyman-Blanchet and Chaix, 1959) may be obtained. 



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