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Toru TANIUCHI Takayuki KANAYA Shuuichi UWABE Takahito KOJIMA Seiji AKIMOTO Isamu MITANI 《Fisheries Science》2004,70(5):845-851
ABSTRACT: Age and growth of alfonsino Beryx splendens (Lowe) were studied using counts of presumed daily incremental growth rings on the transverse section of otoliths of fish collected from the Kanto District, central Japan. Microstructural growth increments were observed from the core to the outermost margin of the broadest of approximately 50 branches formed on the surface of an otolith. Of 98 otoliths examined, 46 were readable. The number of increments and fish lengths ranged from 448 (218 mm fork length [FL]) to 3701 (411 mm FL). The ages of these fish were estimated to be 1 year, 2 months and 10 years, 2 months, respectively, assuming that an increment was formed daily. The von Bertalanffy growth equation combined for males and females was expressed as follows: L t = 542 {1 − exp [−0.133( t + 2.00)]}, where L t is fork length (mm) at yearly age t . The results of the present study were compared with those of other researchers who had studied alfonsino from central Japan. 相似文献
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SHINJI UEHARA CHRISTOPHER T. TAGGART TAKUMI MITANI IAIN M. SUTHERS 《Fisheries Oceanography》2006,15(5):351-362
We assess the effect of drifting seaweed (Sargassum sp.) biomass, geography and hydrography on juvenile yellowtail (Seriola quinqueradiata) abundance variation off the southeast coast of Japan, near the Kuroshio Current. The amount of drifting seaweed mats progressively increased northeastward into the cooler, coastal waters. Frontal structure indexed using a station‐to‐station ΔSST did not explain spatial variation in the seaweed mat distribution, although the western extent of the Kuroshio Current appeared to act as a boundary. Juvenile yellowtail constituted 51–62% of the fish collected in association with drifting seaweed mats in April 1996 and 1997 and 29% in June 1996. The abundance of juvenile yellowtail was positively correlated with seaweed biomass. The geographic distribution of juvenile yellowtail associated with drifting mats varied among sampling periods, being more southwesterly in April and more northeasterly in June. Simple multiple regression models based on seaweed biomass and geographic distribution (latitude) explained between 35% and 43% of the variation in juvenile yellowtail abundance in spring. Associations with spatial and temporal variations in hydrographic conditions did not contribute to explained variation in a meaningful manner. The results presented here indicate that, off the southeast coast of Japan during April, yellowtail juveniles are likely to be most abundant when seaweed biomass is high, occur offshore, and are bounded by the western extent of the Kuroshio Current near the 19–20°C SST isotherm. 相似文献
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Isolation and culture of rabbit primordial germ cells 总被引:2,自引:0,他引:2
Kakegawa R Teramura T Takehara T Anzai M Mitani T Matsumoto K Saeki K Sagawa N Fukuda K Hosoi Y 《The Journal of reproduction and development》2008,54(5):352-357
Primordial germ cells (PGCs) are embryonic precursors of the gametes of adult animals and are considered stem cells of the germline. Since their proliferation in vitro correlates well with the schedule of developmental changes in vivo, they might be interesting research tools for genomic imprinting, germ-cell tumors and fertility. Furthermore, once primordial germ cells are separated and placed on a feeder layer with cytokines, they become cultured pluripotent cell lines called embryonic germ (EG) cells. EG cells share several important characteristics with embryonic stem (ES) cells as they can also contribute to the germ line of chimeras. To investigate the characteristics of PGCs and establish rabbit EG (rEG) cells, we cultured rabbit PGCs (rPGCs) in vitro with various combinations of leukemia inhibitory factor (LIF), basic fibroblast growth factor (bFGF) and forskolin on inactivated mouse embryonic fibroblast (MEF) feeder layers. The present study found PGC proliferation in early cultures and induction of rEG-like colonies. These cells expressed pluripotent markers, such as alkaline phosphatase activity, OCT-4, Sox-2 and SSEA-1, in the undifferentiated state; however, the cells did not develop into a teratoma when injected into the kidney capsules of SCID mice, although the restricted differentiation potentials to neural cells were determined via embryoid body formation. From these characteristics and further characterization of the germ stem cell markers Vasa, SCP-1 and SCP-3, we suggested that these were hybrid cells with characteristics somewhere between PGC and EG cells. 相似文献
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Tomohiro MITANI Makoto TAKAHASHI Koichiro UEDA Hiroki NAKATSUJI Seiji KONDO 《Animal Science Journal》2005,76(5):453-460
Four Holstein cows were used to determine the effect of timing of the feeding of a corn silage (CS)‐based supplement on the feed intake, milk production and nitrogen utilization of grazing dairy cows. The cows were fed the supplement 2 h before grazing (pre‐grazing) or immediately after grazing (post‐grazing). Cows were grazed for 5 h per day under a rotational grazing system. There was no difference in the herbage and total feed intake between treatments. The milk protein yield for pre‐grazing tended to be higher than that for post‐grazing, whereas the milk yield did not differ between treatments. The total nitrogen intake for pre‐grazing tended to be higher than that for post‐grazing (P = 0.06). There was no difference in the urinary nitrogen output between treatments, whereas the proportion of urinary nitrogen output : total nitrogen intake for pre‐grazing tended to be lower than that for post‐grazing (P = 0.06). The milk nitrogen output and nitrogen retention for pre‐grazing tended to be higher than that for post‐grazing (milk nitrogen, P = 0.06; nitrogen retention, P = 0.05). Nitrogen utilization of grazing dairy cows was improved by feeding a CS‐based supplement before grazing. 相似文献
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Joyce Njoloma Kazunori Tanaka Tasuku Shimizu Tomohiro Nishiguchi Muhammad Zakria Ryo Akashi Moriya Oota Shoichiro Akao 《Biology and Fertility of Soils》2006,43(2):137-143
In this study, we used Herbaspirillum sp. B501gfp1 (B501gfp1), an isolate from wild rice, to investigate the interaction between a non-host nitrogen-fixing endophytic bacterium and micropropagated sugarcane plants under aseptic condition. Two Japanese sugarcane plants (Saccharum sp.) cultivars (cvs) NiF8 and Ni15 were inoculated using B501gfp1 in two inoculum doses of 108 and 102 bacterial-cells-per-milliliter suspension. The results showed that bacterial cells colonized both the root and stem tissues, and colonization was apparent in the intercellular spaces. Higher bacterial numbers were detected in plant tissues inoculated with the higher inoculum concentration treatment. Bacterial numbers also varied between the two cultivars, with the higher values determined in cv Ni15. This study provides evidence that Herbaspirillum sp. B501gfp1, a rice isolate, could colonize sugarcane tissues, suggesting non-specificity of host plant among endophytes. 相似文献
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Water shortages during the dry season threaten sustainable agricultural production in Nganjuk District, East Java, Indonesia. To mitigate this problem, farmers adopted conjunctive use of surface water and groundwater, but the sustainability of this practice has not been investigated. This study temporally and spatially assessed water allocation in Nganjuk District when conjunctive irrigation was used. In particular, the land cover, water balance, and irrigation well density (IWD) were analyzed using time series GIS and remote sensing data to obtain their temporal and spatial distributions. First, the land cover was analyzed to determine cropping intensity, and the water balance was analyzed temporally and spatially. IWD was introduced to facilitate the water balance analysis. Second, the land cover, water balance, and IWD results were overlaid. Third, the effectiveness of the IWD method, the magnitude of water shortages, and the sustainability of groundwater resources were considered. Temporal and spatial water shortages in irrigation blocks were observed during the dry season. The change of storage showed a surplus during the wet and early dry seasons and a shortage during the late dry season. The annual water balances indicated that the southern part had a surplus, and the northern part experienced water shortages, especially downstream of the Widas River. Conjunctive use during the late dry season was predominant and concentrated in the southern part (83% of southern blocks). IWD was appropriate for examining groundwater use trends and was effective for expressing average withdrawal data (R 2 = 0.87). 相似文献
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Critical roles of activation-induced cytidine deaminase in the homeostasis of gut flora 总被引:1,自引:0,他引:1
Fagarasan S Muramatsu M Suzuki K Nagaoka H Hiai H Honjo T 《Science (New York, N.Y.)》2002,298(5597):1424-1427
Activation-induced cytidine deaminase (AID) plays an essential role in class switch recombination (CSR) and somatic hypermutation (SHM) of immunoglobulin genes. We report here that deficiency in AID results in the development of hyperplasia of isolated lymphoid follicles (ILFs) associated with a 100-fold expansion of anaerobic flora in the small intestine. Reduction of bacterial flora by antibiotic treatment of AID-/- mice abolished ILF hyperplasia as well as the germinal center enlargement seen in secondary lymphoid tissues. Because an inability to switch to immunoglobulin A on its own does not lead to a similar phenotype, these results suggest that SHM of ILF B cells plays a critical role in regulating intestinal microflora. 相似文献
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