. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Figure 1. Mitotic (A, C) and meiotic (B, D. E) chromosomes of Corbicula leana from Mie Prefecture (A, B) and C. aff. fluminea from Saga Prefecture (C, D. E). Scale bar = 10 /jm. treated with hypotonic solution (SmMKCl), and fixed with Carnoy's fixative according to the procedure of Oka- moto and Arimoto (1986). Cells were isolated from either gill or gonads, placed on slides, and stained with 2% Giemsa in phosphate buffer (pH ). At least 4 clams were examined for each case (, each combination of species and tissue typ
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Figure 1. Mitotic (A, C) and meiotic (B, D. E) chromosomes of Corbicula leana from Mie Prefecture (A, B) and C. aff. fluminea from Saga Prefecture (C, D. E). Scale bar = 10 /jm. treated with hypotonic solution (SmMKCl), and fixed with Carnoy's fixative according to the procedure of Oka- moto and Arimoto (1986). Cells were isolated from either gill or gonads, placed on slides, and stained with 2% Giemsa in phosphate buffer (pH ). At least 4 clams were examined for each case (, each combination of species and tissue type). DNA microfluorometry To compare the relative DNA content of spermatozoa and somatic tissue, cells were isolated on a glass slide by cutting a small piece of gonad or mantle in distilled water with a scalpel and air-drying it before fixing it with 70% ethanol. Spermatozoa and somatic cells from one individ- ual were placed on the same slide. The cells were stained with the DNA-specific dye DAPI, and the relative DNA content (fluorescence intensity) per cell was estimated by microfluorometry as in Komaru el al. (1988). Sperm- atozoa could be easily distinguished from other sperm- atogenic cells because of their elongate and curved mor- phology. Results Mitotic and meiotic chromosomes In four specimens of C leana, we counted 54 chromo- somes in the mitotic metaphase plates of somatic tissue (Fig. 1A) and about 18 chromosomes in the gonad (Fig. IB). In C. aff. fluminea, we observed 36 chromosomes in the mitotic metaphase in 16 cells, but the haploid num- ber of 18 in 8 gonadal cells. Pachytene (Fig. ID), diakine- sis or metaphase I (Fig. IE) figures were observed in the meiotic cells. Relative DNA content of spermatozoa and somatic cells In C. leana, C. and C. fluminea, the rela- tive content of DNA in the spermatozoa was also identical. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability -
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
