The objective of the present study was to investigate yeast communities in kefir grains and viili starters in Taiwan through conventional microbiological cultivation and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The DNA sequencing was used as a validity technique to ensure that all isolates within each group belonged to just one species, and to confirm the identified results of PCR-DGGE. Results indicated that a combination of conventional microbiological cultivation with PCR-DGGE and sequencing could successfully identify 4 yeast species from both types of cultures in Taiwan. Kluyveromyces marxianus, Saccharomyces turicensis, and Pichia fermentans were found in Taiwanese kefir grains with a distribution of 76, 22, and 2%, respectively, whereas Klu. marxianus, Saccharomyces unisporus and P. fermentans were identified in viili starters corresponding to 58, 11, and 31% of the total cell counts, respectively. Furthermore, the culture-independent method was applied to identify the yeast species using DGGE. Only 2 yeast species, Klu. marxianus and S. turicensis, were found in kefir grains and 2, Klu. marxianus and P. fermentans, in viili starters. These results suggest that in samples containing multiple species, PCR-DGGE may fail to detect some species. Sequences of yeast isolates reported in this study have been deposited in the GenBank database under accession nos. DQ139802, AF398485, DQ377652, and AY007920.

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The efFecls of blocking polar body I (FBI) or polar body II (PB2) with four different dosages of cytochalasin B (CB) on the development and ploidy of resultant embryos were studied in the small abalone. HalioUs diversicolor supertexta (Uschke). To block the release of PBl. the fertilized eggs were treated with 0.25. 0.5. 1.0 or 2.0mgL~^ of CB for 10 min beginning at 3 min post-fertilization at 24 °C. To block the release of rB2. lhe fertilized eggs were treated under the same conditions as PBl. except that the treatment was begun 10 min post-fertilization. In the control group, only 41.8% of the cells had a diploid number of J2 chromosomes. although spontaneous haploids (9.0%). tripolids (7.5'^) and aneuploids 141.7'^) were also observed. In CB treatment of PBl and PB2 groups. 5.0-28.6% of the cells remained as diploid. triploids (IO.O-IH.9%) and aneuploids (41.1-(•}l.0%]. With regard to the development of the resultant embryos, the proportion of normal embryos in the control group was 87%. while in the treatment groups, the proportions of normal embryos in the PBl and PB2 groups were 57-58% and 53-56% in the 0.25 mg L"* and 0.5 mg L"' CB treatments, respectively. From this data on induced triploids and the resultant development of normal embryos, the proportions suggest that 0.25-().5mgL~' of CB for lOmin was sufficient for blocking the release of PBl or PB2 to produce triploids in the small abalone.

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