Metabolism of PG in man: Effect of furosemide on the excretion of the main metabolite of PG F2α

The excretion rates of main urinary metabolite of PG F₂α were measured radioimmunologically in 4 healthy persons and in 13 essential hypertensives. The resting values were 9.3±0.73 in the former and 10.4±2.17 ng/min in the latter. There was no significant differences between them. The excretion of the metabolite decresed prominently after the administration of furosemide. The percent decrease was 57% in healthy persons and 70% in essential hypertension. The percent result supports that furosemide inhibit the catabolism of PG F₂α.     

Nucleic acid metabolism in cold-treated wheat embryos

The incorporation of ₃₂P into nucleic acid fractions separatedon a MAK column was compared for normally germinated and cold-treatedwheat embryos. ₃₂P accumulation in DNA fraction was decreasedby cold treatment, although that in the RNA fractions was slightlypromoted. The synthesis of the fraction, probably mRNA, elutedafter the peak of heavy rRNA was enhanced in cold-treated embryosand suppressed when the embryos were cold-treated in the presenceof 8-azaguanine, an inhibitor of vernalization. (Received May 2, 1975; )     

Changes in nucleic acids, protein-nitrogen and amino-nitrogen of excised winter wheat embryos during vernalization

Embryos excised from winter wheat grains were vernalized for10–50 days with or without sugar (sucrose). Determinationswere made of fresh weight, protein-nitrogen, amino-nitrogen,RNA and DNA. There was no change in the contents of RNA of wheatembryos during the vernalization. The incorporation of ³²P intonucleic acid in wheat embryos during vernalization in the presenceof sugar was much higher than that of embryos vernalized withoutsugar. From these results we assumed that RNA turnover occurredduring the vernalization. There was no significant differencein the nucleotide composition of RNA extracted between the vernalizedand unvernalized embryos. The RNA of wheat embryos was separatedinto two fractions. Proportions of these two RNA fractions variedin the course of cold treatment, and similar changes were foundin developing wheat leaves. (Received July 25, 1974; )     

Application of L-DNA to the study of the specific DNA recognition mechanism of bleomycin.

The hexadeoxynucleotide analog, L-d(CGCGCG) composed of L-deoxyribose was synthesized and clearly shown to have the same conformation and dynamic properties with natural D-d(CGCGCG) except for chirality with CD spectra. This unnatural hexanucleotide was not cleaved by bleomycin, an antitumor DNA cleaving drug, but was able to bind to the DNA binding domain of bleomycin to a similar extent with the natural one. These results strongly suggest the importance of the other moiety than the DNA binding domain for the specific DNA recognition of bleomycin. Thus, L-oligonucleotides are useful for the study of DNA-drug interactions.     

Variable sensitivity of Trichoderma viride to Medicago sativa saponins

Eight saponins were isolated from alfalfa roots (Medicago sativa). The sensitivity of Trichoderma viride to the saponin varied with the individual saponin isolate. Seven isolates appeared to contain the aglycone, medicagenic acid, and while the other did not, it inhibited the growth of the fungus at higher concentrations than the other isolates. One pair and a triplet of saponins with divergent R_fs evoked near identical biological responses suggesting structural similarity toxic to T. viride.     

Phylogeography of Fischer’s blue,Tongeia fischeri,in Japan: Evidence for introgressive hybridization

The widespread lycaenid butterfly Tongeia fischeri is distributed from eastern Europe to northeastern Asia and represented by three geographically isolated populations in Japan. In order to clarify the phylogeographic history of the species, we used sequences of three mitochondrial (COI, Cyt b and ND5) and two nuclear (Rpl5 and Ldh) genes of 207 individuals collected from 55 sites throughout Japan and five sites on the Asian continent. Phylogenetic trees and the median-joining network revealed six evolutionary mitochondrial haplotype clades, which corresponded to the geographic distribution of the species. Common ancestors of Japanese T. fischeri might have come to Japan during the mid-Pleistocene by multiple dispersals of continental populations, probably via a land bridge or narrow channel between western Japan and the Korean Peninsula. The geographical patterns of variation of mitochondrial and nuclear markers are discordant in northeastern Kyushu, possibly as a result of introgressive hybridization during the ancient contact between the Kyushu and Shikoku populations in the last glacial maximum. The phylogeographic pattern of T. fischeri in Japan are probably related to the geological history, Pleistocene climatic oscillations and distribution of the host plant.     

Thermophilic and halophilic β-agarase from a halophilic archaeon Halococcus sp. 197A

An agar-degrading archaeon Halococcus sp. 197A was isolated from a solar salt sample. The agarase was purified by hydrophobic column chromatography using a column of TOYOPEARL Phenyl-650 M. The molecular mass of the purified enzyme, designated as Aga-HC, was ~55 kDa on both SDS-PAGE and gel-filtration chromatography. Aga-HC released degradation products in the order of neoagarohexose, neoagarotetraose and small quantity of neoagarobiose, indicating that Aga-HC was a β-type agarase. Aga-HC showed a salt requirement for both stability and activity, being active from 0.3 M NaCl, with maximal activity at 3.5 M NaCl. KCl supported similar activities as NaCl up to 3.5 M, and LiCl up to 2.5 M. These monovalent salts could not be substituted by 3.5 M divalent cations, CaCl₂ or MgCl₂. The optimal pH was 6.0. Aga-HC was thermophilic, with optimum temperature of 70 °C. Aga-HC retained approximately 90 % of the initial activity after incubation for 1 hour at 65–80 °C, and retained 50 % activity after 1 hour at 95 °C. In the presence of additional 10 mM CaCl₂, approximately 17 % remaining activity was detected after 30 min at 100 °C. This is the first report on agarase purified from Archaea.     

Variation in life-history traits of male Japanese fluvial sculpin Cottus pollux in relation to nest abundance along a stream course

Life-history theory predicts the occurrence of variation in the life-history traits of fish populations under different environmental conditions; however, most studies have focused on such variation between geographically separated populations. We compared breeding characteristics and life-history traits of the Japanese fluvial sculpin (Cottus pollux), a bottom-dwelling nest-holding fish, between two adjacent sites sub-divided by a weir along a stream course in central Japan. Males in the area with a lower abundance of nest sites reached sexual maturity at an earlier age and had a shorter life span than males in the area with sufficient nest abundance. Size-dependent male reproduction was found only in areas with a shortage of nest sites, supporting the assumption of competitive exclusion among males for nests. Females matured at the same age in both sites with no differences in age-specific growth rates and mortality. Our results provide evidence for life-history variation in age and size at maturity and age-specific mortality schedule of males in nest-holding fishes in a single stream population via different sexual selection regimes related to differences in nest abundance between sites.