Communication TAKASHI NAKASE,* AKIKO TAKEMATSU, MUTSUMI ITOH AND TEUN BOEKHOUT'

Transcription

1 J. Gen. App!. Mierobiol., 36, (1990) Short Communication CONSPECIFICITY OF BULLERA DERXII, SINENSIS AND BULLERA ALGA VAR. BULLERA LACTIS TAKASHI NAKASE,* AKIKO TAKEMATSU, MUTSUMI ITOH AND TEUN BOEKHOUT' Japan Collection of Microorganisms, The Institute of Physical and Chemical Research (RIKEN), Wako, Saitarna 351-O1, Japan ' Centraalbureau voor Schimmelcultures, Yeast Division, Julianalaan 67a, 2628 BC Delft, The Netherlands (Received May 16, 1990) Bu//era sinensis and Bu//era alba var. lactis were described by Li (1) in 1982 as new taxa of ballistosporous yeasts. According to Li, B. sinensis forms subglobose to ellipsoidal ballistospores, while B. alba var. lactis forms exclusively apiculate ballistospores which resemble those of B, alba. Because of this feature, she proposed a new variety, B. alba var. lactis, in spite of the fact that the physiological characteristics of B. alba var. lactis are quite similar to those of B. sinensis. She considered that "the morphology of ballistospores is of prime importance." Nakase and Suzuki (3) described Bu//era derxii in 1986 based on three isolates from dead leaves of Oryza saliva and Miscanthus sinensis. They did not compare their isolates with B. sinensis and B. alba var. lactis because they did not notice Li's (1) paper. Bu//era derxii showed physiological characteristics similar to B. sinensis and B. alba var. lactis. We compared four taxa chemotaxonomically, using the following strains: B. alba JCM 2954 (=CBS 501), B. alba var. lactis JCM 6254, T (=CBS 7237), B. derxii JCM 5280, T (=CBS 7225) and B. sinensis JCM 6253, T (=CBS 7238). Ubiquinones were extracted from cells harvested in the stationary growth phase, and purified and identified according to procedures described by Nakase and Suzuki (5). DNAs were extracted and purified according to Nakase and Suzuki (4) after disruption of cells harvested in the logarithmic growth phase, by a Braun's mechanical cell homogenizer. The DNA base composition was calculated from the * Address reprint requests to: Dr. T. Nakase, Japan Collection of Microorganisms, The Institute of Physical and Chemical Research (RIKEN), Hirosawa 2-1, Wako, Saitama , Japan. 209

2 210 NAKASE, TAKEMATSU, ITOH, and BOEKHOUT VOL. 36 thermal denaturation temperature (Tm), and it was also analyzed by high performance liquid chromatography (HPLC) after hydrolysis of the DNA with nuclease P1 and alkaline phosphatase as described in a previous paper (6). Xylose in the cells was analyzed by the method of Suzuki and Nakase (7). Electrophoretic comparison of enzymes was carried out according to Yamazaki and Komagata (9). The ubiquinone system of B. sinensis was composed of Q-10 (96.1 mol%) and Q-9 (3.9 mol%) and that of B. alba var. lactis of Q-10 (93.9 mol%) and Q-9 (6.1 mol%). The major ubiquinone of B, alba and B. derxii already had been reported as Q-10 (3, 8). The values for the mol% G + C of DNA are shown in Table 1. Bu//era sinensis and B. alba var. lactis showed similar G + C values, i.e mol% (from Tm) or 54.3 mol% (by HPLC) for B. sinensis, and 56.8 mol% (from Tm) or 54.9 mol% (by HPLC) for B. alba var. lactis. Bu//era alba showed a somewhat lower mol% G + C compared with B. sinensis and B. alba var. lactis, i.e mol% (from T m) or 47.0 mol% (by HPLC). The reason for the remarkable discrepancy in B. alba of 7.5 mol% G + C between the spectrophotometric and HPLC methods is not yet known. The G + C of B. derxii was reported as mol% (3). These results suggest that B. alba and B. alba var. lactis belong to different species. This is supported by the comparison of electrophoretic enzyme patterns (Table 2). Of the nine enzymes examined, enzyme bands of malate dehydrogenase, fumarase, esterase and lactate dehydrogenase appeared in both B. alba and B. alba var. lactis. The similarity of the banding patterns of these enzymes between these two taxa was calculated as 9.5% (Fig. 1), which indicated that they are not closely related. Enzyme bands of glutamate dehydrogenase, malate dehydrogenase, fumarase, esterase and lactate dehydrogenase appeared in B. alba var. lactis, B. derxii and B, sinensis. The similarity of the banding patterns of these enzymes among these three taxa was calculated as % (Fig. 1). Thus the conspecificity Table 1. DNA base composition in strains of Bullera alba, Bullera alba var. lactis, Bu//era derxii and Billera sinensis.

3 1990 B. der.xii, B. sinensis and B. alba var. lactis?ll

4 217 NAKASE, TAKEMATSU, ITOH, and BOEKHOUT VOL. 36 Fig. 1. Similarity matrix based on electrophoretic patterns of enzymes from strains of Bullera alba, Bullera alba var. lactis, Bullera derxii and Bullera sinensis. % Similarity= (NS/ND + NS) x 100. NS, number of enzyme bands showing identical mobilities; ND, number of enzyme bands showing different mobilities. A difference of 0.02 in the Rm value is regarded as significant. of B. derxii, B. sinensis and B. alba var, lactis is strongly indicated. The production of ballistospores by B. alba var. lactis and B. sinensis was poor on various media. Globose, subglobose, napiform or ampulliform ballistospores were formed at sterigmata in cultures of B, alba var. lactis grown on corn meal agar, after incubation for 22 days at room temperature. The ballistospores could not be collected on a glass slide, because they were poorly discharged. We confirmed Li's (1) findings that B, sinensis and B. alba var. lactis had similar physiological characteristics. Bu//era derxii had physiological characteristics similar to both taxa. These three differed physiologically from B. alba in their inability to assimilate lactose. On the basis of our observations, we conclude that B. derxii, B. sinensis and B. alba var. lactis represent one and the same species. Bu//era sinensis has priority over the other two taxa. In conclusion, the following synonymy is given. Bu//era sinensis Li, Acta Microbiol. Sin. 22: 22 (1982). = But/era alba (Hanna) Derx var. lactis Li, Acta Microbiol. Sin. 22: 23 (1982). =Bullera derxii Nakase et Suzuki, J. Gen. App/. Microbiol. 32: 127 (1986). REFERENCES 1) Li, M.-X., Studies on Sporobolomycetaceae I. Taxonomy of Bullera. Acta Microbial. Sin., 22, (1982). 2) Nakase, T. and Komagata, K., DNA base composition of some species of yeasts and yeast-like fungi. J. Gen. App!. Microbiol., 17, (1971). 3) Nakase, T. and Suzuki, M., Bullera derxii sp. nov. and Bullera pseudoalba sp. nov. isolated from dead leaves of Oryza sativa and Miscanthus sinensis. J. Gen. App!. Microbiol., 32, (1986). 4) Nakase, T. and Suzuki, M., Bullera megalospora, a new species of yeast forming large ballistospores isolated from dead leaves of Oryza sativa, Miscanthus sinensis and Sasa sp. in Japan. J. Gen. App!. Microbiol., 32, (1986). 5) Nakase, T. and Suzuki, M., The ubiquinone system in strains of species in the ballistospore-forming yeast genera Sporidiobolus. Sporobolomyces and Bullera. J. Gen. App!. Microbiol., 32, (1986). 6) Nakase, T., Itoh, M., Takematsu, A., and Komagata, K., Candida tanzawaensis, a new species of yeast isolated from moss collected in Japan. Trans. mycol. Soc. Jpn., 29, (1988). 7) Suzuki, M. and Nakase, T., The distribution of xylose in the cells of ballistosporous

5 1990 B. derxii B. sinensis and B alba var. lactis?13 yeasts-application of high performance liquid chromatography without derivatization to the analysis of xylose in whole cell hydrolysates. J. Gen. App!. Microbiol., 34, (1988). 8) Yamada, Y., Ohishi, T., and. Kondo, K., The coenzyme Q system in strains of some yeasts and yeast-like fungi. J. Gen. Appl. Microbiol., 29, (1983). 9) Yamazaki, M. and Komagata, K., Taxonomic significance of electrophoretic comparison of enzymes in the genera Rhodotorula and Rhodosporidium. Int. J. Syst. Bacteriol., 31, (1981).