Freshwater Algae from Skarvsnes, Near Syowa Station, Antarctica (Biology and Medical Science)

This contribution is the result of the studies on the collections obtained by Dr. M. OHNO during the 16th Japanese Antarctic Research Expedition in 1975-76. The author determined 134 taxa of fresh and marine forms of algae, comprising 51 taxa of blue-green algae, 71 taxa of diatoms and 12 taxa of green algae. The characteristic feature of the algal flora of the Skarvsnes area, especially that in Lake Hunazoko, is the rich marine species of diatoms, while freshwater species of blue-green algae are abundant in the streams. Judging from this, the nature of the algal species from the lakes in the Skarvsnes area is characteristic of high content of salt, and those from the stream water is entirely of a freshwater nature. Many species of marine diatoms are found in the inland lakes; especially notable in Melosira (3 taxa), Coscinodiscus (8 taxa), Actinocyclus (2 taxa), Hyalodiscus (1 taxon) and Charotia (2 taxa) of centricous diatoms, and Cocconeis (1 taxon), Trachyneis (1 taxon) and Fragilariopsis (3 taxa) of pennaceous diatoms, while the species of blue-green algae belonging to the Oscillatoriaceae were found in the streams

コルステロールの胆汁酸への転換に関する肝臓中必須脂肪酸の役割及びそのコレステロール系胆石形成に対する意義

京都大学0048新制・論文博士医学博士論医博第227号新制||医||85B(附属図書館)1057(主査)教授 木村 忠司, 教授 伊藤 鉄夫, 教授 本庄 一夫学位規則第5条第2項該当Kyoto UniversityDA

コレステロールの胆汁酸への転換に関する肝臓中必須脂肪酸の役割及びそのコレステロール系胆石形成に対する意義

京都大学0048新制・論文博士医学博士論医博第227号新制||医||85B(附属図書館)1057(主査)教授 木村 忠司, 教授 伊藤 鉄夫, 教授 本庄 一夫学位規則第5条第2項該当Kyoto UniversityDA

The detection of the genotoxic potential of extremely low frequency electromagnetic field

The Drosophila strain that is genetically sensitive to various mutagens was introduced in order to assess the genotoxic potential of extremely low frequency (ELF) magnetic field. The males of this strain have high sensitivity to mutagens, because they have double mutant alleles, one can't carry out a normal nucleotide excision repair against somatic mutations and the other fail to arrest cell cycle when the replicated chromosome has any aberration. If the males were exposed to mutagen, the fitness of the males would be lower than that of the females owing to accumulation of somatic mutations on single X chromosome. It is possible to estimate the genotoxic potential exposing larvae to the ELF magnetic field during the whole larval development and measuring the male-to-female ratio which would be less than that of the control group, if the genotoxic potential exists. Therefore, we exposed this strain to extremely low frequency (10μT and 100μT) magnetic field, and compared the sex ratio of the exposed groups with that of the control. The result showed that the number of males which were exposed to the 10μT ELF magnetic field reduced by about 5% compared with that of the control, however it was not the statistically significant level. The number of males exposed to the 100μT field significantly reduced by 14%. The numbers of females with two X chromosomes and normal repair genes hardly changed among those of control and exposed groups, but slight decrease (2%) was observed in the number of females exposed to 100μT. These results suggest that the male X chromosomes in somatic cells that are deficient in two kinds of repair genes could accumulated mutations induced by the mutgenic effect of the extremely low frequency magnetic field

Observation of Allende and Antarctic meteorites by monochromatic X-ray CT based on synchrotron radiation

Three-dimensional CT images of the Allende meteorite with a high resolution of 10μm have been obtained nondestructively by a monochromatic X-ray computed tomography (CT) based on synchrotron radiation (SR). The metallic minerals, matrix and chondrules can be clearly observed in the CT images. The CT values, which express the image intensity, allow a quantitative elemental analysis including such as difference in the metallic minerals, i. e., pentlandite and troilite, using the comparison of CT images and elemental images measured by a computer-aided microanalyzer (CMA). The three-dimensional CT images indicate that the metallic minerals surround some chondrules, and the largest chondrule has two humps and well crystallized olivine in its center. These observations suggest that the three-dimensional SR-CT system is a useful method for identification of internal structures of stony meteorites. Additionally, information obtained from the CT images of Antarctic meteorites confirms that the SR-CT system can be applied to classification of stony chondrites

日本におけるAtorella vanhoeffeni(刺胞動物門,鉢虫綱,カンムリクラゲ目)の広範囲な地理的分布

Medusae of a rare, small scyphomedusa, Atorella vanhoeffeni Bigelow, 1909 (Cnidaria, Scyphozoa, Coronatae), were collected and/or photographed at three sites in Japan: Notojima, Ishikawa Prefecture, in the Sea of Japan; Osezaki, Shizuoka Prefecture, on the Pacific coast; and Yonaguni Island, Okinawa Prefecture, in the East China Sea. In Japanese waters this species has been previously reported only from Kakeroma Island, Kagoshima Prefecture. The detailed morphology is described based on a medusa from Yonaguni Island