Round Shape Enlargement of the Yeast Spheroplast of Saccharomyces cerevisiae by HM-1 Toxin
| Autor: | Yasuhiro Furuichi, Tetsuya Kimura, Tadazumi Komiyama |
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| Rok vydání: | 2002 |
| Předmět: | |
| Zdroj: | Biological and Pharmaceutical Bulletin. 25:959-965 |
| ISSN: | 1347-5215 0918-6158 |
| Popis: | The effects of HM-1 killer toxin (HM-1) on yeast spheroplasts of Saccharomyces cerevisiae were examined under osmotically stabilized conditions. Prolonged incubation of spheroplasts in nutrient-rich media resulted in an increase in volume, accompanied by aberrant morphological changes. By contrast, spheroplasts were enlarged, maintaining a round shape, when incubated in HM-1 media. The required 50% effective dose of HM-1 was as low as 2.2 x 10(-8) M, and this effect by HM-1 was specific to yeast sensitive to RM-1. Some parts of the enlarged spheroplasts were stable, but the round shape was deformed as HM-1 was removed from the medium. In both the control and HM-1-treated spheroplasts, the total protein and DNA content were increased by approximately three and four times in response to their incubations, respectively. Cytochemical analysis by 4'6-diamidino-2-phenylindol (DAPI) staining showed multiple nuclei. Consistently, actin patches of cells were evenly distributed in both the control and HM-1-treated spheroplasts. A similar enlargement of spheroplasts was observed with lipophilic antifungal compounds, aculeacin A and papulacandin B, but the effects were distinct from those of HM-1 because the spheroplasts resulted in lysis after a long incubation. The molecular mechanism(s) behind this unique observation remains to be studied, but it is clear that HM-1 is an excellent tool for studying yeast cell biology. |
| Databáze: | OpenAIRE |
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