The sex determining gene of medaka: a Y-specific DM domain gene (DMY) is required for male development     

Masaru Matsuda  Yoshitaka Nagahama  Tohru Kobayashi  Chika Matsuda  Satoshi Hamaguchi  Mitsuru Sakaizumi 《Fish physiology and biochemistry》2003,28(1-4):135-139

Although the sex-determining gene Sry has been identified in mammals, no comparable genes have been found in non-mammalian vertebrates. To clone positionally the sex-determining region of the medaka, Oryzias latipes, we generated a Y congenic strain to highlight the genetic differences between the X and Y chromosomes from inbred strains of medaka. We used recombinant breakpoint analysis and deletion analysis of the Y chromosome of a congenic XY female to restrict the sex-determining region to 250-kb stretch of the Y chromosome. Shotgun sequencing of this region predicted 27 genes. Three of these genes were expressed during sexual differentiation. However, only one gene was Y specific. The full-length cDNA sequence of this gene encodes a putative protein of 267 amino acids, including the highly conserved DM domain. We thus named it DMY. To establish a role for DMY during sexual differentiation, we screened wild medaka populations for naturally occurring DMY mutants. Two XY females with distinct mutations in DMY were found in separate populations. The first heritable mutant – a single insertion in exon 3 and the subsequent truncation of DMY – resulted in all XY female offspring. Similarly, the second XY mutant female showed reduced DMY expression with a high proportion of XY female offspring. Furthermore, during normal development, DMY is expressed only in somatic cells of XY gonads. These findings strongly suggest that the sex-specific DMY is required for normal testicular development and is a prime candidate for the medaka sex-determining gene.  相似文献   

Genomic Reassortants of Pandemic A (H1N1) 2009 Virus and Endemic Porcine H1 and H3 Viruses in Swine in Japan     

Rikio KIRISAWA  Yoshitaka OGASAWARA  Hayato YOSHITAKE  Asuka KODA  Tokujiro FURUYA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2014,76(11):1457-1470

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Bovine papillomavirus type 10 with a deletion associated with a lingual papilloma in a cow     

Wei Zhu  Jianbao Dong  Kazuyuki Uchida  Ken-ichi Watanabe  Hiroyuki Nakayama  Yoshitaka Goto  Takeshi Haga 《Veterinary journal (London, England : 1997)》2014,199(2):303-305

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Larval rearing without aeration: a case study of the seven-band grouper <Emphasis Type="Italic">Epinephelus septemfasciatus</Emphasis> using a wave maker     

Yoshitaka Sakakura  Shigeaki Shiotani  Masashi Shiozaki  Atsushi Hagiwara 《Fisheries Science》2007,73(5):1199-1201

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Changes in seawater tolerance during the development of eyed-stage embryos in shishamo smelt Spirinchus lanceolatus (Hikita)     

Shinya Mizuno  Yoshitaka Sasaki  & Kazushi Imada 《Aquaculture Research》2005,36(6):615-619

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Estimation of flow in a rearing tank of marine fish larvae by simplified numerical computation—a case of two-dimensional flow     

Shigeaki Shiotani  Atsushi Hagiwara  Yoshitaka Sakakura  Hisashi Chuda   《Aquacultural Engineering》2005,32(3-4):465-481

Marine fish larvae are fragile against physical stress. However, few studies have been conducted to evaluate the flow field in a rearing tank, which is assumed to provide a high degree of physical stress to marine fish larvae. The flow field in a rearing tank (volume of 1 m³) is generated by aerators, which are commonly used to provide oxygen.

This paper is a report on the estimation of stationary flow in the rearing tank of marine fish larvae. The larvae are seven band grouper larvae of Epinephelus septemfasciatus, which have a very low survival rate immediately after the hatching of eggs. The experiments of rearing of seven band grouper larvae were carried out using rearing tanks with four aeration rates (1000, 200, 50 ml/min, and no aeration). The effects of aeration on the survival and floating death of seven band grouper larvae were examined. The experiments confirmed that the mass mortality of seven band grouper larvae depends on the flow rate in the rearing tank. Aeration at 200 ml/min resulted in the highest survival and growth rates of grouper larvae.

Larvae-rearing experiments provided evidence that the flow rates of the rearing tanks are very important design aspects of rearing tanks. The estimation of flow in a rearing tank for an aerating rate of 200 ml/min was carried out by numerical calculation. The computation was simplified by a two-dimensional flow based on experimental results. The calculated flow in the rearing tank was compared with the experimental one. The calculation of the stationary flow in the rearing tank showed good qualitative and quantitative agreement with the experimental results. The numerical estimation of the flow in a rearing tank of marine fish larvae was confirmed to be effective and satisfactory for the design of a tank that would provide optimum performance.  相似文献   

Validation of a food-frequency questionnaire for cohort studies in rural Japan     

Ogawa K  Tsubono Y  Nishino Y  Watanabe Y  Ohkubo T  Watanabe T  Nakatsuka H  Takahashi N  Kawamura M  Tsuji I  Hisamichi S 《Public health nutrition》2003,6(2):147-157

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MET amplification leads to gefitinib resistance in lung cancer by activating ERBB3 signaling     

Engelman JA  Zejnullahu K  Mitsudomi T  Song Y  Hyland C  Park JO  Lindeman N  Gale CM  Zhao X  Christensen J  Kosaka T  Holmes AJ  Rogers AM  Cappuzzo F  Mok T  Lee C  Johnson BE  Cantley LC  Jänne PA 《Science (New York, N.Y.)》2007,316(5827):1039-1043

The epidermal growth factor receptor (EGFR) kinase inhibitors gefitinib and erlotinib are effective treatments for lung cancers with EGFR activating mutations, but these tumors invariably develop drug resistance. Here, we describe a gefitinib-sensitive lung cancer cell line that developed resistance to gefitinib as a result of focal amplification of the MET proto-oncogene. inhibition of MET signaling in these cells restored their sensitivity to gefitinib. MET amplification was detected in 4 of 18 (22%) lung cancer specimens that had developed resistance to gefitinib or erlotinib. We find that amplification of MET causes gefitinib resistance by driving ERBB3 (HER3)-dependent activation of PI3K, a pathway thought to be specific to EGFR/ERBB family receptors. Thus, we propose that MET amplification may promote drug resistance in other ERBB-driven cancers as well.  相似文献   

Three new algorithms to calculate the irreplaceability index for presence/absence data     

Nobuyuki Tsuji  Yoshitaka Tsubaki 《Biological conservation》2004,119(4):487-494

The irreplaceability index is used for determining the priority of sites for conservation. We propose three new and simple algorithms for calculating it from presence/absence data without any statistical assumptions when the representative combination size is the minimum. The rare species algorithm gives accurate results but takes the longest calculation time. The species richness algorithm gives approximated results and takes the shortest calculation time. The combined algorithm is intermediate in accuracy and calculation time. We applied the combined algorithm to real data of butterflies in the Kanto district, central Japan, and derived irreplaceability values.  相似文献   

Comparison of collagen content, distribution and architecture among the pectoralis, iliotibialis lateralis and puboischiofemoralis muscles with different myofiber composition in Silky cocks     

Yoshi-Nori NAKAMURA  Hisao IWAMOTO  Shoji TABATA  Yoshitaka ONO  Nobuya SHIBA  Shotaro NISHIMURA 《Animal Science Journal》2003,74(2):119-128

The total amount of collagen, the relative distributions of types I and III collagens in perimysium and endomysium, and the collagen fiber architecture were compared among the pectoralis (PT), iliotibialis lateralis (ITL) and puboischiofemoralis (PIF) muscles in Silky cocks. All of the myofibers in the PT muscle were type IIB, the myofibers in the ITL muscle were divided into type IIA, 41.7% and IIB, 58.3%, and the PIF muscle was composed of type I, 24.6%; IIA, 64.6%; and transitional, 10.8%. The total amount of collagen differed significantly among the PT (2.92 mg/g), PIF (4.20 mg/g) and ITL (8.06 mg/g) material, where only the PIF was a whole muscle with epimysium. On the image analysis of the immunohistochemical preparations, the percentage area of perimysial collagen to the total area in each type differed significantly among the PIF, PT and ITL muscles, where it was 26.8, 50.0 and 74.4% for the type I collagen and 27.4, 32.9 and 61.7% for the type III collagen, respectively. In the scanning electron micrography of the perimysium in macerated preparations, thick bundles of collagen fibers were observed in the ITL muscle, thinner but broad platelets in the PT muscle, and a coarse tissue of thinner collagen fibers in the PIF muscle. However, the endomysial fabric of collagen fibrils was similar among the muscles. Small, transverse collagen fibers, which branched off from the thicker perimysia, occupied narrow interendomysial spaces and separated the primary myofiber fasciculi. The results indicate that the ITL muscle, localized in the distorted and overextended part of the leg and subject to strong external forces, had highly developed perimysial collagen fiber bundles, but the ITL endomysial collagen architecture was similar to that of the PT and PIF muscles.  相似文献