Short Communication SPECTROPHOTOMETRIC ANALYSIS OF YEASTS: CYTOCHROME SPECTRA OF THE GENUS YAMADAZYMA

In previous papers, the cytochrome absorption spectra of some sporogenic yeasts were reported by Fiol and Claisse (10) in the genus Kluyveromyces, Fiol and Hmama (11) in the genus Ambrosiozyma, Hormoascus and Hyphopichia, Fiol and Claisse (12) in the genus Pichia, and in some Candida Montrocher and Claisse (14, 15). We have now examined the cytochrome absorption spectra of the nitratenegative yeasts of the genus Yamadazyma (5), equipped with the coenzyme Q9 system as reported by Yamada et al. (17) and Billon-Grand (3, 4) . Taxonomic implications were established in relation to the vitamin requirements according to Fiol (8, 9), Billon-Grand (2), and the GC contents as reported by Barnett et al. (1), Billon-Grand (2) and Starmer et al. (16). Materials and methods. Yeast strains: Sixteen type strains were examined (Tables 1, 2, 3). They came from the yeast collection of the Centraal Bureau voor Schimmelcultures (CBS) Delft, The Netherlands. Cytochrome spectra: The strains were inoculated in YPGA medium (1 % yeast extract, l% bacto peptone, 2% glucose, 0.002% adenine and 2.3% agar) with 0.3 ml of a preculture grown aerobically for 24 h at 25°C in a liquid YPGA medium. After aerobic growth on solid medium for 3 days at 25°C, the yeast cultures were collected for spectrophotometry. Cytochrome absorption spectra were determined with whole-cell pastes 0.7 mm thick according to Claisse et al. (6, 7). The cytochromes were reduced by adding dithionite at room temperature; after freezing the cells in liquid nitrogen, the spectra were graphed with a Cary 219 spectropho-