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81.
The influence of castration on the development of the thymus in neonatal rats was studied to elucidate when after birth the thymus comes under inhibitory regulation by the testis in rats. The relative and absolute weights of the thymus were measured five days after castration these cases. No excessive changes in the weights of the thymus with castration were observed by 31 days after birth. Significant changes in the thymus appeared in the relative weight at 36-day-castration. The absolute weight of the thymus was also significantly increased after 41-day-castration. These findings suggest that in rats the inhibitory regulation of the thymus by testis development does not appear before at least 31 days of age. 相似文献
82.
Hiroyuki Imachi Ken Aoi Eiji Tasumi Yumi Saito Yuko Yamanaka Yayoi Saito Takashi Yamaguchi Hitoshi Tomaru Rika Takeuchi Yuki Morono Fumio Inagaki Ken Takai 《The ISME journal》2011,5(12):1913-1925
Microbial methanogenesis in subseafloor sediments is a key process in the carbon cycle on the Earth. However, the cultivation-dependent evidences have been poorly demonstrated. Here we report the cultivation of a methanogenic microbial consortium from subseafloor sediments using a continuous-flow-type bioreactor with polyurethane sponges as microbial habitats, called down-flow hanging sponge (DHS) reactor. We anaerobically incubated methane-rich core sediments collected from off Shimokita Peninsula, Japan, for 826 days in the reactor at 10 °C. Synthetic seawater supplemented with glucose, yeast extract, acetate and propionate as potential energy sources was provided into the reactor. After 289 days of operation, microbiological methane production became evident. Fluorescence in situ hybridization analysis revealed the presence of metabolically active microbial cells with various morphologies in the reactor. DNA- and RNA-based phylogenetic analyses targeting 16S rRNA indicated the successful growth of phylogenetically diverse microbial components during cultivation in the reactor. Most of the phylotypes in the reactor, once it made methane, were more closely related to culture sequences than to the subsurface environmental sequence. Potentially methanogenic phylotypes related to the genera Methanobacterium, Methanococcoides and Methanosarcina were predominantly detected concomitantly with methane production, while uncultured archaeal phylotypes were also detected. Using the methanogenic community enrichment as subsequent inocula, traditional batch-type cultivations led to the successful isolation of several anaerobic microbes including those methanogens. Our results substantiate that the DHS bioreactor is a useful system for the enrichment of numerous fastidious microbes from subseafloor sediments and will enable the physiological and ecological characterization of pure cultures of previously uncultivated subseafloor microbial life. 相似文献
83.
An unusual hemangioma of the face, found in a 7-year-old girl in the masticator space and consisting of multiple lobes, is reported. Direct angiography was effective in clarifying the space occupied by the tumor. It was removed through a combined approach, using both temporal and oral incisions, with almost no bleeding. 相似文献
84.
When a mixture of creatinine, phenylalanine and glucose in diethylene glycol-water solution was heated for 2 h at 128 degrees C, a mutagen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), was found to be produced, identified by high-performance liquid chromatography, and UV-visible and mass spectrometries. The yield of PhIP was 3.6 nmoles/mmole original creatinine. PhIP was originally isolated from cooked beef, and this study shows creatinine, phenylalanine and glucose to be the probable precursors of PhIP in beef. 相似文献
85.
Primula sieboldii E. Morren is a heterostylous clonal herb that is widely distributed in Japan but in danger of extinction in the wild. The existence of pollinators in each habitat is imperative for its long-term survival, because seeds can be produced only by insect cross-pollination between different flower morphs. In this study, we identified the pollinators of P. sieboldii in a wild habitat in Hiroshima as those insects that we observed to (a) put the proboscis into a corolla tube, (b) deposit pollen grains on the proboscis, and (c) have a proboscis of appropriate length and width. Effective pollinators were identified from their contribution to pollination. In 2015 and 2016, the flower visitations of 232 and 558 insects, respectively, were recorded and 85 and 13 insects were captured. Two Bombylius species, B. major L. and B. shibakawae Matsumura, accounted for 90% of flower-visiting insects in both years. All 14 species that we captured were considered pollinators of P. sieboldii, because they had proboscises that were long enough to reach pollen and that had pollen grains deposited on them. The total visitation rate of “Bombyliidae” was the highest among all pollinator categories. The results of potential pollen transport per flower per hour, which was based on total pollen number and total visitation rate of each pollinator category, indicated that “Bombyliidae” species were the most effective pollinators of P. sieboldii in this habitat. 相似文献
86.
Aoi Ogawa Junpei Dake Yu-ki Iwashina Toshinobu Tokumoto 《Reproductive biology and endocrinology : RB&E》2011,9(1):11
Background
The African clawed frog, Xenopus laevis, is widely used in studies of oogenesis, meiotic cell cycle and early embryonic development. However, in order to perform such studies, eggs are normally collected after the injection of hCG into the dorsal lymph sac of fully-grown female frogs following pre-injection of PMSF. Although this protocol is established and used as standard laboratory approach, there are some concerns over whether the injections could cause the transmission of deleterious microorganisms. Moreover, these injection protocols require a competent skilled worker to carry out the procedure efficiently. 相似文献87.
88.
Shinya Aoi Takahiro Kondo Naohiro Hayashi Dai Yanagihara Sho Aoki Hiroshi Yamaura Naomichi Ogihara Tetsuro Funato Nozomi Tomita Kei Senda Kazuo Tsuchiya 《Biological cybernetics》2013,107(2):201-216
Obstacle avoidance during locomotion is essential for safe, smooth locomotion. Physiological studies regarding muscle synergy have shown that the combination of a small number of basic patterns produces the large part of muscle activities during locomotion and the addition of another pattern explains muscle activities for obstacle avoidance. Furthermore, central pattern generators in the spinal cord are thought to manage the timing to produce such basic patterns. In the present study, we investigated sensory-motor coordination for obstacle avoidance by the hindlimbs of the rat using a neuromusculoskeletal model. We constructed the musculoskeletal part of the model based on empirical anatomical data of the rat and the nervous system model based on the aforementioned physiological findings of central pattern generators and muscle synergy. To verify the dynamic simulation by the constructed model, we compared the simulation results with kinematic and electromyographic data measured during actual locomotion in rats. In addition, we incorporated sensory regulation models based on physiological evidence of phase resetting and interlimb coordination and examined their functional roles in stepping over an obstacle during locomotion. Our results show that the phase regulation based on interlimb coordination contributes to stepping over a higher obstacle and that based on phase resetting contributes to quick recovery after stepping over the obstacle. These results suggest the importance of sensory regulation in generating successful obstacle avoidance during locomotion. 相似文献
89.
90.
Iguchi H Urashima Y Inagaki Y Ikeda Y Okamura M Tanaka T Uchida A Yamamoto TT Kodama T Sakai J 《The Journal of biological chemistry》2007,282(26):19052-19061