Method for efficiently obtaining fertilized eggs from the black scraper Thamnaconus modestus by natural spawning in captivity     

Kaori Mizuno  Sonoko Shimizu-Yamaguchi  Chiemi Miura  Takeshi Miura 《Fisheries Science》2012,78(5):1059-1064

To develop an efficient and stable method for enhancing spawning of black scrapers in captivity, we examined the following three factors: (1) different kinds of spawning substrate, (2) the area of the spawning substrate, (3) the grain size of the spawning substrate. The results demonstrated that sand is the optimum spawning substrate when compared to a hard polyvinyl chloride sheet, a piece of shading net, or artificial spawning grass. No difference was observed in the spawning frequency between a small sand bed of area 400?cm² and sand spread over the bottom of the tank to an area of 7085?cm², since the egg masses were spawned on the sand in a small area approximately 15?cm in diameter. In addition to the spawned eggs, the small movable sand bed is useful for subsequent harvest. No differences were observed in either the spawning frequency or the hatching rate when using sand beds with different grain sizes. In large-scale egg collection trials, an average of 33 egg masses from which an average of 403,000 larval fish were obtained. We can therefore conclude that the procedure developed in the present study is applicable to the commercial-scale seed production of black scraper.  相似文献   

Microbiological and thin-layer chromatographic identification of benzylpenicillin and ampicillin in animal body     

H Yoshimura  O Itoh  S Yonezawa 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1981,43(6):833-840

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Role of acidification elicited by sialylation and sulfation of zona glycoproteins during oocyte maturation in porcine sperm-zona pellucida interactions     

Lay KM  Oshiro R  Arasaki C  Ashizawa K  Tatemoto H 《The Journal of reproduction and development》2011,57(6):744-751

The porcine zona pellucida (ZP) undergoes biochemical changes during the final phase of maturation prior to fertilization. The present study was conducted to elucidate whether the acidification of ZP glycoproteins during porcine oocyte maturation influences sperm-ZP interactions. Two-dimensional gel electrophoresis clearly demonstrated that ZP acidification occurred in accordance with the sialylation and sulfation of ZP glycoproteins in oocytes matured for 44 h. The increases in the incidences of sperm penetration and polyspermy with the progress of the IVM culture period were significantly suppressed by ZP desialylation on treatment with neuraminidase as a consequence of reductions in the number of sperm bound to ZPs and the acrosome reaction (AR) in ZP-bound sperm (P<0.05). In contrast, the blocking of ZP sulfation by NaClO(3) treatment during IVM markedly reduced the incidence of polyspermy with no inhibitory effect on penetration, but the number of sperm bound to ZPs and the rate of AR-inducing sperm were decreased to the same level as in desialylated oocytes. The results indicate that ZP sulfation influences sperm-ZP interactions in a ZP sialylation-independent manner. Moreover, sialylation and sulfation were not associated with a protective proteolytic modification of the ZP matrix before fertilization. These findings suggest that ZP acidification elicited by the sialylation and sulfation of ZP glycoproteins during oocyte maturation contributes to the porcine ZP acquiring the capacity to accept sperm.  相似文献   

Developing neuromuscular junctions: first signs of chemical transmission during formation in tissue culture   总被引：3，自引：0，他引：3  

N Robbins  T Yonezawa 《Science (New York, N.Y.)》1971,172(981):395-398

Electrophysiological study of rat neuromuscular junctions in the early stage of formation in tissue culture showed that chemical transmission begins with discrete, localized release of transmitter about the time when nerve-muscle contacts are first visible with light microscopy. Noncontractile myotubes with as few as three nuclei showed evidence of junctional transmission.  相似文献   

On the optimum mutation rate and optimum dose for practical mutation breeding     

K. Yonezawa  H. Yamagata 《Euphytica》1977,26(2):413-426

Summary Optimum mutation rates for practical purpose were discussed based on the theoretically derived formulae, and mutagen doses giving the optimum mutation rates were estimated from the experiments reported hitherto. It was suggested that in cereal crops such as rice and barley, considerably low mutation rates as with the mutagen doses lower than 5 kR of or X rays and 2%·h of EMS are appropriate for obtaining directly applicable mutants. High mutation rates seem to be limited to the production of some rare breeding stocks.  相似文献   

Epizootiological studies on R plasmid with carbadox resistance   总被引：2，自引：0，他引：2  

K Ohmae  S Yonezawa  N Terakado 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1983,45(2):165-170

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Molecular cloning of goat 20alpha-hydroxysteroid dehydrogenase cDNA     

Jayasekara WS  Yonezawa T  Ishida M  Yamanouchi K  Nishihara M 《The Journal of reproduction and development》2004,50(3):323-331

20Alpha-hydroxysteroid dehydrogenase (20alpha-HSD), which catalyzes the conversion of progesterone to its inactive form 20alpha-dihydroprogesterone, is expressed in murine placenta and has been suggested to play roles in maintaining pregnancy. To understand the role of 20alpha-HSD during pregnancy in the goat, as a first step, cloning and sequencing of 20alpha-HSD cDNA were performed. The full nucleotide sequence of 20alpha-HSD cDNA was determined on samples obtained from the corpus luteum at the luteal phase of the estrous cycle and the placenta in late pregnancy by RT-PCR and 3' and 5' RACE systems. Cloned 20alpha-HSD cDNA consisted of 1124 bp and belonged to the aldo-keto reductase superfamily. From the start codon to stop codon there were 323 amino acids, the same as in other species. To verify whether the protein derived from goat 20alpha-HSD cDNA had 20alpha-HSD activity, the cDNA was expressed by bacteria. Bacterially expressed goat 20alpha-HSD protein showed 20alpha-HSD enzyme activity. A tissue distribution study demonstrated that 20alpha-HSD was expressed in the placenta, but not in the adrenal gland, liver and spleen during pregnancy. The present study suggests that goat 20alpha-HSD is another member of the aldo-keto reductase superfamily and that it plays a role in the placenta during pregnancy.  相似文献   

The semifossorial function of the forelimb in the common rice tenrec (Oryzorictes hova) and the streaked tenrec (Hemicentetes hemispinosus)     

Endo H  Oishi M  Yonezawa T  Rakotondraparany F  Hasegawa M 《Anatomia, histologia, embryologia》2007,36(6):413-418

The forelimb muscles of the two semifossorial species of Tenrecidae (Oryzoryctinae: common rice tenrec; and Tenrecinae: streaked tenrec) were compared macroscopically with those of the unspecialized terrestrial-arboreal species, the Talazac long-tailed tenrec. The structure of the hand was also observed using three-dimensional reconstructed images from computed tomography data. The two semifossorial species had similar muscle weight ratios in the lateral and long heads of M. triceps brachii and M. teres major. A similar hand skeleton structure (in which the second, third and fourth metacarpals and phalanges act as a digging apparatus) was observed in both species. Our observations confirm that both these species have muscular-skeletal adaptations supporting fossorial locomotion. As each species belongs to a monophyletic subfamily within the Tenrecidae isolated in Madagascar, such semifossorial adaptations are assumed to have evolved convergently.  相似文献   

Sampling performance and operational quality of a frame trawl used to catch juvenile fish     

Kazuhiko Itaya  Yasuzumi Fujimori  Daisuke Shiode  Ichiro Aoki  Takashi Yonezawa  Susumu Shimizu  Teisuke Miura 《Fisheries Science》2001,67(3):436-443

SUMMARY: A sampling trawl with a rigid mouth; that is, the frame trawl, was designed so as to catch the large larval and juvenile fish more efficiently. The net consisted of four 13 m panels (nylon multifilament and twine diameter φ 0.75 mm, mesh size 8 mm). The frame of the net's mouth was composed of four stainless steel pipes (length 4 m, diameter φ 76 mm, thickness 5 mm). Several operations were conducted to investigate the capability of catching juveniles. A lot of Sardinops melanostictus juveniles, which are generally difficult to catch, were caught during every operation. Underwater observations proved that juveniles could not elude the capture. The frame trawl requires no special handling and is possible to operate in a rough sea.  相似文献   

Antimicrobial susceptibilities and bacteriological characteristics of bovine Pseudomonas aeruginosa and Serratia marcescens isolates from mastitis     

Ohnishi M  Sawada T  Hirose K  Sato R  Hayashimoto M  Hata E  Yonezawa C  Kato H 《Veterinary microbiology》2011,154(1-2):202-207

The presence of metallo-β-lactamase (MBL)-producing and multidrug-resistant Pseudomonas aeruginosa (MDRP) strains among bovine isolates of Gram-negative bacilli, and O-serotypes of bovine Serratia marcescens and P. aeruginosa isolates have been reported rarely. The aims of this study were to (1) elucidate antimicrobial susceptibilities and O-serotypes of P. aeruginosa and S. marcescens isolates from bovine mastitis and the presence of MBL-producers and MDRP strains among them and (2) evaluate their relationships to human isolates. We investigated the MICs of 24 antimicrobials and O-serotypes for 116 P. aeruginosa and 55 S. marcescens isolates in Japan, primarily in 2006. A total of 171 isolates exhibited high antimicrobial susceptibilities with the exception of a partial drug. P. aeruginosa isolates exhibited high susceptibilities of ≥ 95.7% to ciprofloxacin, imipenem, meropenem, piperacillin, ceftazidime, cefepime, cefoperazone/sulbactam, amikacin, tobramycin, and gentamicin; however, they exhibited a susceptibility of only 69.8% to aztreonam. They exhibited substantial resistances to ceftriaxone, enrofloxacin, cefotaxime, and moxalactam. S. marcescens isolates exhibited high susceptibilities of ≥ 90.9% to kanamycin, ceftiofur, sulfamethoxazole-trimethoprim, and the 15 aforementioned drugs, but exhibited resistance to minocycline. Neither MBL-producers nor MDRP strains were detected among the 171 strains. The dominant serotypes of P. aeruginosa isolates were OG, OA, OB, OI, OF, OE, and OK; those of S. marcescens isolates were O6 and O5. Every S. marcescens isolate was pigmented. These findings suggest that bovine P. aeruginosa and S. marcescens isolates differ from human isolates from both antibiogram and phenotypic perspectives, and could help to evaluate differences in bacteriological characteristics between bovine and human isolates.  相似文献