Centrifugal precipitation chromatography -- a novel chromatographic system for fractionation of polymeric pigments from black tea and red wine

A novel chromatographic system was developed and first applied to the fractionation of polymeric pigments from black tea and red wine. Centrifugal precipitation chromatography (CPC) generates solvent gradients through a long separation channel under a centrifugal force field. Tea and wine extracts are precipitated in a hexane- or methyl tert-butyl ether-rich environment and are exposed to a gradually increasing ethanol concentration. This causes a repetitive precipitation and dissolution of the biopolymers along the channel. Consequently, they are eluted in the order of their solubility in the organic solvent. It is shown by HPLC analysis of the separated fractions that monomers elute first, whereas fractionated polymers can be found at the end of the chromatographic run. This novel method allows gentle fractionation of polymeric tea and wine constituents and also has potential for use in preparative-scale separations.     

Effects of Acid Stress on Reproductive Functions in Immature Carp, Cyprinus Carpio

Changes in plasma cortisol, estoradiol-17β (E2) and 11-ketotestosterone (11-KT) levels under chronic acid exposure were examined to clarify the endocrinological effects of lowered environmental pH on gametogenesis in immature and gonadal developing carp, Cyprinus carpio. Plasma cortisol levels increased markedly 3 hours after the acid exposure and high levels were maintained for 48 hours, and then gradually decreased. Plasma E2 levels were significantly elevated and peaked at 1 week after the acid exposure. After that, E2 levels decreased gradually, but remained at significantly higher levels than the control group even at 4 weeks after the exposure. Plasma 11-KT levels showed no significant change throughout the experiment. These results indicate that acidic water disrupts the endocrine system that may have adverse effects on gametogenesis in freshwater fish.     

Zoosporicidal activity of polyflavonoid tannin identified in Lannea coromandelica stem bark against phytopathogenic oomycete Aphanomyces cochlioides

In a survey of nonhost plant secondary metabolites regulating motility and viability of zoospores of the Aphanomyces cochlioides, we found that stem bark extracts of Lannea coromandelica remarkably inhibited motility of zoospores followed by lysis. Bioassay-guided fractionation and chemical characterization of Lannea extracts by MALDI-TOF-MS revealed that the active constituents were angular type polyflavonoid tannins. Commercial polyflavonoid tannins, Quebracho and Mimosa, also showed identical zoosporicidal activity. Against zoospores, the motility-inhibiting and lytic activities were more pronounced in Lannea extracts (MIC 0.1 microg/mL) than in Quebracho (MIC 0.5 microg/mL) and Mimosa (MIC 0.5 microg/mL). Scanning electron microscopic observation visualized that both Lannea and commercial tannins caused lysis of cell membrane followed by fragmentation of cellular materials. Naturally occurring polyflavonoid tannin merits further study as potential zoospore regulating agent or as lead compound. To the best of our knowledge, this is the first report of zoosporicidal activity of natural polyflavonoid tannins against an oomycete phytopathogen.     

Diatoms and the ecological conditions of their growth in sea ice in the arctic ocean

A summer field survey off Point Barrow, Alaska, revealed that Arctic sea ice develops a growth of phytoplanktonic diatoms. The diatoms are found in a brine solution in microfissures between ice crystals on the underside of the ice. The chlorophyll content of this layer is 100 times more than that of the surrounding sea waters; this has led to a hypothesis that a considerable fraction of the primary production of the Arctic Sea may be carried out in sea ice, especially during the spring and early summer months.     

Genetic variation in resistance of the tiger pufferfish Takifugu rubripes to a host-specific monogenean parasite Heterobothrium okamotoi

Fisheries Science - The tiger pufferfish Takifugu rubripes is one of the most valuable aquaculture species in Japan. In this study, we investigated the genetic variation in resistance to...     

古梅灵芝和梅子精抗过敏性作用的研究

抑制组胺游离和肠管收缩等过敏反应的研究表明,对于由Ｃｏｍｐｏｕｎｄ４８／８０或ＩｇＥ抗血清反应引起的老鼠腹腔细胞中组胺的游离及外源组胺引起的土拨鼠肠管的收缩,古梅灵芝和梅子精均有明显的抑制作用．     

湖北省杜仲种质资源收集与繁殖保存研究

以湖北省杜仲资源调查为基础,分析了湖北省杜仲资源的分布特点及生长差异,对不同类型的杜仲种质资源进行了收集和繁殖试验,确定了影响杜仲繁殖保存效果的主导因子,为湖北省杜仲种质资源的保存和利用提供了依据。     

Influence of the spawning environment on final maturation and spawning in Japanese dace, Tribolodon hakonensis

Results of the present study demonstrated that a specific combination of spawning substrate and water current was indispensable for the spawning of mature Japanese dace, Triborodon hakonensis. It became evident that the environmental factors acted as a trigger for endocrine changes leading to final maturation in this species.     

Ecological studies of Yersinia enterocolitica I. Dissemination of Y. enterocolitica in pigs

Pigs were examined on five farms for carrier status of Yersinia enterocolitica. Yersinia enterocolitica biovar 4, serovar 3, phagovar VIII was isolated consistently from the feces of fattening pigs on one farm and sporadically from those of similar pigs on the other farms and of sows on all five farms, during a one-year period of weekly surveys. Seasonal variation was not a feature of fattening pigs on a highly contaminated farm. In other pigs, however, the organisms were not isolated during the summer months. On a highly contaminated farm, the organisms were excreted in the feces of 8 to 15-week-old pigs within 1–3 weeks of entering pens which were thought to be contaminated with the organisms. On a detailed observation of natural infection of Y. enterocolitica in eight pigs, the organism appeared in the pigs' feces within 2–7 weeks of them being moved to a pen which had been washed thoroughly after becoming contaminated, by a previous group of pigs, with feces containing 10⁵ viable organisms per g. Thus, Y. enterocolitica is apparently transmitted from infected feces or picked up from the floor of a contaminated pen, and the regular schedule of pig movement among the pens is an important factor in the spread of Y. enterocolitica within a piggery. Intestinal colonization continues for a long time and does not occur by re-infection. The organisms were not isolated from eight pigs at the time of slaughter, and their serum O-agglutinin titers were $\text{1}\text{40}$ or less. Thus, circulating antibody may not inhibit intestinal colonization by Y. enterocolitica.