Masashi Ryuzaki

Evidence for heteromorphic sex chromosomes in males of Rana tagoi and Rana sakuraii in Nishitama district of Tokyo (Anura: Ranidae).

Karyotypes of the Tago brown frog Rana tagoi and stream Tago brown frog Rana sakuraii from a mountain region in the Nishitama district in Tokyo were examined by conventional Giemsa staining, C-banding and late replication (LR)-banding. Chromosome number was 2n = 26 in all cases. The 26 chromosomes consisted of five (1–5) pairs of large chromosomes and eight (6–13) pairs of small chromosomes. Chromosome 10 had a secondary constriction on the long arm. In all frogs, on chromosome pair 8, the XX/XY type sex chromosome was present. C-banding analysis indicated that, in R. sakuraii, neither the X nor Y chromosome possessed interstitial C-bands but each had centromere staining, while in R. tagoi, an interstitial C-band was present on the long arm of the X chromosome. The Y chromosome had no interstitial C-band. LR-banding analysis demonstrated the X and Y chromosomes to have a LR-band on the short arm and two LR-bands, each on the long arm, and the bands on both species to be essentially the same. Heteromorphic sex chromosomes in males of R. sakuraii and R. tagoi were identified for the first time in this study.

Heat production during early development of frog egg

Abstract The production of heat in the fertilized eggs, during the early development of the Japanese pond frog, Rana brevipoda porosa, was measured using a pyroelectric detector constructed with a polyvinylidene fluoride film. One and 2 μW of heat production was detected during the cleavage periods in the embryogenesis of the 2-cell embryo and the 4-cell embryo, respectively. The heat production increased stepwise with the cleavage in the embryogenesis of each stage. In comparison with the heat production during the inter-cleavage periods, a larger amount was noted at the cleavage periods in the two embryonic stages.

Karyotypes of Rana tagoi Okada with diploid number 28 in the Chausu Mountains of the Minamishinshu district of Nagano Prefecture, Japan (Anura: Ranidae)

Karyotypes of Tago’s brown frog Rana tagoi from the Chausu mountains in Minamishinshu of Nagano Prefecture were examined by conventional Giemsa staining, C-banding and late replication (LR)-banding. Chromosome number was 2n = 28 in all cases. The 28 chromosomes consisted of four pairs (1–4) of large biarmed chromosomes, two pairs (5–6) of telocentric chromosomes and eight pairs (7–14) of small biarmed chromosomes. Chromosome pair 11 had a secondary constriction on the long arm. In females, the C-band on the long arm of chromosome pair 6 was detected in both homologs, but was absent from the arms of the homologs of chromosome pairs 5 and 9. In males, C-bands were found in the long arms of both homologs of chromosome pairs 5 and 6, were present only in one homolog of chromosome pair 5 for certain male specimens and found in only one homolog of chromosome pair 9. Specimens of R. tagoi (2n = 28) should thus have two pairs of telocentric chromosomes to provide the same number of chromosome arms, these originating quite likely from chromosome pair 1 in the 26-chromosome specimens by centric fission. Heteromorphic sex chromosomes of the XX-XY type in R. tagoi (2n = 28) in the Chausu mountains were identified. Karyotypes of tail-tip cells from a hybrid tadpole between female R. tagoi (2n = 26) from the Hinohara village in Tokyo and male R. tagoi (2n = 28) from the Chausu mountain population were examined by squash preparation. Chromosome number was 2n = 27 in all tadpoles. The 27 chromosomes consisted of one chromosome set of R. tagoi (2n = 28) and one of R. tagoi (2n = 26).

Positional distribution of constituent fatty acids in phosphatidylethanolamine during early development in Rana nigromaculata

Qualitative and quantitative changes in phosphatidylethanolamine (PE) were analyzed in the eggs, embryos and tadpoles of the Japanese pond frog, Rana nigromaculata, at various stages of development. The weight percentage of PE to total phospholipid and to total lipid was about 15-18% and about 3-4%, respectively, during embryonic life. At all stages from the unfertilized egg to the feeding tadpole, the major fatty acids at the 1-position of PE were palmitic, stearic and oleic acids. At the 2-position, arachidonic, oleic, palmitic, stearic and linoleic acids were present during embryonic life. The most abundant fatty acid at the 2-position was arachidonic acid at the unfertilized egg and hatching embryo stages. However, palmitic acid was the most prevalent 2-fatty acid at the posthatching tadpole and the feeding tadpole stages. Thus, there were marked changes in the positional distribution of the constituent fatty acids in PE during development.

Study on amphibian lipids—II. Characteristic constituents of monoglycosylceramides from the skin of three frog species

Abstract 1. Monoglycosylceramide was isolated from the skin of three frog species, Rana nigromaculata, Bufo bufo japonicus and Xenopus laevis, and the chemical constituents were compared. 2. Monoglycosylceramides of Rana nigromaculata and Xenopus laevis contained more galactose than glucose as the hexose components, and mainly 4-sphingenine (D-erythro-1,3-dihydroxy-2-amino-4-trans-octadecene) and sphinganine (D-erythro-1,3-dihydroxy-2-aminooctadecane) as the long chain bases. 3. Skin glycolipids from Bufo bufo japonicus were characterized by glucose and 4D-hydroxy-sphinganine (D-ribo-1,3,4-trihydroxy-2-aminooctadecane) as their major hexose and base components, respectively. 4. Both hydroxy and nonhydroxy fatty acids ranging from C14 to C26 were distributed in the glycolipids. The fatty acid composition differed in different frog species.

PHOTON EMISSION DURING CLEAVAGE OF FROG EGGS

Emission of light was detected from the surface of embryos of the frog, Rana japonica, during early cleavage by a photon counting and an “analog separation (integrated photons) method”. The light‐emission from an egg was more than 5.6 times 10−‐19 W at the beginning of the first cleavage.

Characterization of the constituent fatty acids in phosphatidylinositol during early development in Rana nigromaculata.

1. Qualitative and quantitative changes in phosphatidylinositol (PI) were analyzed in the eggs, embryos and tadpoles of the Japanese pond frog, Rana nigromaculata, at various stages of development. 2. The weight percentage of PI to total phospholipid and lipid was about 8.4-15.2% and 1.4-2.6%, respectively, during embryonic life. 3. At the early stages of the unfertilized egg and the two-cell embryo, the predominant fatty acids are palmitic, stearic, oleic and linoleic acid. From the dorsal lip, early gastrula stage and beyond, the percentage of linoleic acid declines and there is an increase in palmitoleic acid. A relatively large amount of arachidonic acid was noted at the unfertilized egg stage at the 1-position. 4. A large amount of arachidonic acid was also observed at the 2-position of PI in the unfertilized egg, hatching embryo and post-hatching tadpole stages, relative to palmitic and stearic acid. 5. Palmitic and stearic acid were increased at the 2-position of PI in the other embryo and the feeding tadpole stages, relative to arachidonic acid, indicating a shift in these molecular species. 6. Thus, there were marked changes in the positional distribution of the constituent fatty acids in PI during early development of R. nigromaculata.

Characterization of the Constituent Fatty Acids in the Phosphoglycerides of Chemically Induced Polycystic Disease and Gastric Tumor in Rat

The positional distribution of fatty acids in choline‐ and ethanolamine phosphoglycerides from the livers of polycystic disease‐bearing rats and stomachs of gastric tumor‐bearing rats was analyzed and compared to that in normal rat liver and stomach. Polycystic disease and gastric tumors were induced with N‐Methyl‐N′‐Nitro‐N‐Nitrosoguanidine. There was no significant difference between diseased and normal organs with respect to the composition of fatty acids at the 1‐position, except that diseased livers exhibited an increase of approximately 22% in 16: 0 fatty acid and a decrease of approximately 12% in 18: 1 fatty acid. However, in diseased organs, there were marked quantitative changes in the positional distribution of fatty acids at the 2‐position, their composition exhibiting greater saturation. Furthermore, in diseased organs, there was an increase in 15: 0 fatty acid at the 2‐position of ethanolamine phosphoglycerides.