Proceedings of the Japan Academy, Series B

A 44-year-old female diagnosed as having chronic myelogenous leukemia (CML) in the acute phase is found to possess three cell lines, 46, XX (35%), 47, XXX (50%), and 48, XXXX (15%), in cultured lymphocytes, although her skin culture shows exclusively a 47, XXX karyotype. By contrast, all of the bone marrow cells examined in the acute phase as well as in remission and relapse has a 47, XXX, t(9;22) constitution, with some random karyotypic variations in the initial acute phase before therapy. These findings seem to provide additional evidence for the monoclonal origin of Ph¹-positive cells in CML.

View full abstract

The male germ-line chromosomes of the Japanese newt, Cynops pyrrhogaster, are revised in its 9 geographical populations by the use of the improved cytological techniques, and their karyotypes are found to be quite uniform and stable. The spermatogonial chromosomes (2n, 24) are all bi-armed and their morphometric characteristics are shown, by way of example, for the Hirosaki-population (Table I). A pair of no. 11 chromosomes somewhat differ each other in shape. No secondary constrictions and satellites are distinguished. Twelve bivalents are observed in Meiosis-I and the same number of dyads in Meiosis-II. Additional observations of mitotic chromosomes of larvae (Hirosaki) reveal that their somatic cell karyotype is similar to the spermatogonial karyotype.

View full abstract

The mechanism of preferential destruction of chloroplast nucleoids (ct-nucleoids) from the male parent in young zygotes in Chiamydomonas reinhardii was studied using an epifluorescent microscopy and translation inhibitors. When the young zygotes were treated with inhibitors (chloramphenicol, erythromycin) of translation in chloroplasts, the preferential destruction of ct-nucleoids of male parent occurred like the control. However, the addition of an inhibitor (cycloheximide) of translation in the cytoplasm inhibited preferential destruction of ct-nucleoids of male origin 100%. The results suggest that soon after mating, the newly synthesized protein is involved in the preferential digestion of the chloroplast nucleoids of male origin.

View full abstract

Show abstractHide abstract

The mechanism of preferential destruction of chloroplast nucleoids from the male parent in young zygotes in Chiamydomonas reinhardii was studied using inhibitors of transcription, ultraviolet irradiation and an epifluorescent microscopy. Addition of an inhibitor (rifampisin) of transcription in chloroplasts has no effect on the preferential destruction of chloroplast nucleoids while addition of inhibitors (actinomycin D, α-amanitin) inhibited remarkably the preferential destruction of chloroplast nucleoids. In addition, UV irradiation of male gametes had no effect on the preferential destruction of chloroplast nucleoids while irradiation of female parent blocked the preferential destruction approx. 100%. The results suggest that soon after mating, the RNA which is synthesized in the female nucleus is involved in the preferential destruction of chloroplast nucleoids of male origin and there is a coupled RNA-protein system for the preferential destruction in young zygotes.

View full abstract

Download PDF (391K)

Register with J-STAGE for free!