Morphological study on the stomach of the lesser mouse deer (Tragulus javanicus) with special reference to the internal surface.     

S Agungpriyono  Y Yamamoto  N Kitamura  J Yamada  K Sigit  T Yamashita 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》1992,54(6):1063-1069

The stomach of the lesser mouse deer (Tragulus javanicus) was observed macroscopically. It consisted of only three compartments, rumen, reticulum and abomasum without omasum. The rumen was S-shaped with large ventral and caudoventral blind sacs and the reticulum was larger than the abomasum. Internally, the rumen was covered with numerous ruminal papillae even on the pillars and the ruminoreticular fold. These papillae were leaf- or tongue-like shaped and varied in size and density. The reticulum had honey-combed crests and the secondary crests were found rarely. The lips of the reticular groove were prominent and more developed in the aboral part than in the oral one. A sac-like transition zone, which had more prominent mucosal folds than had the floor of the reticular groove, was observed between the caudal end of the reticular groove and the abomasum. Mucosal folds of the abomasum were spiral, low but rather thick. These findings were discussed in view of comparison with other ruminants and of possible functional implications.  相似文献   

Underwater sound detection by cephalopod statocyst     

Kenzo Kaifu  Tomonari Akamatsu  Susumu Segawa 《Fisheries Science》2008,74(4):781-786

Abstract:   The cephalopod receptor of particle motion was identified. In a previous study, it was suggested that statocysts served this function, but there was no direct supporting evidence, and epidermal hair cells had not been conclusively ruled out. Experiments on Octopus ocellatus were conducted using respiratory activity as an indicator of sound perception. Intact animals clearly responded to 141-Hz particle motion at particle accelerations below 1.3 × 10⁻³ m/s², and the mean perception threshold at this frequency was approximately 6.0 × 10⁻⁴ m/s². Specimens in which the statoliths had been surgically removed did not show any response for accelerations up to 3.9 × 10⁻³ m/s² at 141 Hz, which was approximately 16 dB greater than the mean perception threshold at this frequency. Specimens that had undergone a control operation in which the statoliths remained intact showed positive responses at 2.8 × 10⁻³ m/s² for the same frequency stimulus. This indicates that the statocyst, which is morphologically similar to the inner ear system in fish, is responsible for the observed responses to particle motion in O. ocellatus . This is the first direct evidence that cephalopods detect kinetic sound components using statocysts.  相似文献   

Reproductive season and female maturity size of coconut crab <Emphasis Type="Italic">Birgus latro</Emphasis> on Hatoma Island,southern Japan     

Taku Sato  Kenzo Yoseda 《Fisheries Science》2008,74(6):1277-1282

Information about reproductive season, size at sexual maturity and size-dependent reproductive potentials is important for efficient resource management. Such information is necessary to determine seasonal closures and minimum legal size limits. To conserve resources of coconut crab Birgus latro, which are in danger of extinction due to excessive exploitation, their reproductive season, female size at functional maturity and relationship between female size and reproductive potentials were investigated. The reproductive season started in early June and ended late August, and females with higher reproductive potentials showed a tendency to spawn early in the reproductive season. The prohibition of exploiting the resources during the reproductive season, especially early in the season, would be appropriate for sustainability of high reproductive outputs. Fifty percent of investigated females matured functionally at 24.5-mm thoracic length (TL). However, the size at which all females reached functional maturity was 32.3 mm TL, and there was a wide variation in the size of functional maturity among individuals. We must determine minimum legal size by taking the variation into account to allow all individuals to mate at least once before they are caught, which may prevent serious depression in reproductive rate and genetic diversity.  相似文献   

Influence of light intensity on feeding, growth, and early survival of leopard coral grouper (Plectropomus leopardus) larvae under mass-scale rearing conditions     

Kenzo Yoseda  Kazuhisa Yamamoto  Kimio Asami  Masayuki Chimura  Koji Hashimoto  Shinichi Kosaka 《Aquaculture (Amsterdam, Netherlands)》2008,279(1-4):55-62

This study investigated the effect of different light intensities on feeding, growth and survival of early stage leopard coral grouper Plectropomus leopardus larvae. Four different light intensities (0, 500, 1000 and 3000 lx) were used and larvae were kept under constant light conditions from 0 day after hatching (DAH) to 5 DAH. The larvae were fed a small S-type of Thai strain rotifers at a density of 20 individuals/mL from 2 DAH. The number of rotifers in larval digestive organ and total length of larvae were examined at 3 h intervals between 04:00 and 22:00 h on 3 DAH, and thereafter at 6 h intervals until the end of the experiment (5 DAH). Four experimental trials of the larval rearing were repeated using by 60 kL mass-scale rearing tanks. The results indicate that coral grouper larvae are visual feeders and their food intake increases with increasing light intensity. Food intake of larvae reared at 3000 lx was significantly higher than those reared at 0–1000 lx on 3 DAH despite being the first-feeding day (P < 0.01). On 4 DAH, total length of larvae reared at 3000 lx was significantly larger than those reared at the lower light intensities (0, 500 and 1000 lx), and thereafter light intensity significantly influenced larval feeding and growth until the end of the experiment. Survival on 5 DAH did not show a significant difference between light intensities, but survival rate at 3000 lx and 1000 lx had a tendency to be higher than those reared at the lower light intensities (0 and 500 lx). In contrast, larvae reared at 0 lx exhibited stagnant and/or negative growth. These results indicate that light intensity is significantly the factor affecting larval feeding, growth, and survival in coral grouper larvae under the rearing conditions.  相似文献   

The maturation of the salmon GnRH system and its regulation by gonadal steroids in masu salmon     

M. Amano  K. Ikuta  S. Kitamura  K. Aida 《Fish physiology and biochemistry》1997,17(1-6):63-70

Pituitary gonadotropin (GTH) secreting cells and brain gonadotropin-releasing hormone (GnRH) secreting neurons are known to be subjected to feedback control by gonadal steroid in teleosts. In masu salmon, Oncorhynchus masou, salmon GnRH (sGnRH) neurons in the ventral telencephalon (VT) and the preoptic area (POA) are involved in the control of GTH cells because sGnRH synthesis in these areas is activated with gonadal maturation. In this study, we attempted to clarify mechanisms of feedback control of sGnRH neurons by gonadal steroids. We examined the effects of 17-methyltestosterone (MT) on sGnRH synthesis in yearling and 2-year-old female fish (which were immature during experimentation in May), and the effects of castration on sGnRH synthesis in underyearling precocious male fish in August. sGnRH synthesis in the POA, but not in the VT, was increased by MT administration in 2-year-old females only, indicating higher sensitivity to MT in the preoptic sGnRH neurons. Castration increased sGnRH synthesis in the VT but not in the POA. These results suggest that sGnRH neurons in the VT and those in the POA are differentially regulated by gonadal steroids.  相似文献   

Immunohistochemical evaluation of a malignant phecochromocytoma in a wolfdog   总被引：1，自引：0，他引：1  

Sako T  Kitamura N  Kagawa Y  Hirayama K  Morita M  Kurosawa T  Yoshino T  Taniyama H 《Veterinary pathology》2001,38(4):447-450

A malignant pheochromocytoma with multiple metastases was diagnosed in a 7-year-old male wolfdog that resulted from a cross between an eastern timber wolf (Canis lupus lycaon) and an Alaskan malamute. A yellowish white neoplastic mass approximately 10 cm diameter was found in the right adrenal gland. The neoplasm penetrated through the wall of the caudal vena cava. A diagnosis of pheochromocytoma was established by histopathologic and immunohistochemical procedures. Immunohistochemically, the neoplastic cells expressed chromogranin A, substance P, synaptophysin, Leu-7, protein gene product 9.5, methionine-enkephalin, S100 protein, and galanin. Multiple metastatic tumors were found in the kidneys, spleen, lungs, heart, and liver.  相似文献   

Immunohistochemical localization of inhibin subunits in the testis of the bull     

Matsuzaki S  Cruzana MB  Budipitojo T  Hondo E  Watanabe G  Taya K  Sasaki M  Kitamura N  Yamada J 《Anatomia, histologia, embryologia》2001,30(6):375-378

The differential localization of the inhibin beta subunits betaA and betaB in the testis of adult bull was studied using specific monoclonal and polyclonal primary antibodies. Inhibin betaA- and betaB-subunits were localized only in the Sertoli cells. The inhibin betaA-subunit was observed in the cytoplasm while the betaB-subunit was localized in the nucleus. No specific findings depending on spermatogenic stages were observed among the seminiferous tubules. Moreover, the inhibin alpha-subunit was not detected in the testis of the bulls. In addition, no inhibin subunits were detected in the Leydig cells and spermatogenic cells. These findings indicate the presence of betaA- and betaB-subunits in the bull, which may suggest a possibility that activin is produced and/or stored in the Sertoli cells and regulates spermatogenesis in an autocrine/paracrine manner. Moreover, the inhibin betaB-subunit may be produced in the nucleus but the functional meaning of this is not yet clear.  相似文献   

Concentrations and specific antibodies to staphylococcal enterotoxin-C and toxic shock syndrome toxin-1 in bovine mammary gland secretions,and inflammatory response to the intramammary inoculation of these toxins     

Kuroishi T  Komine K  Kai K  Itagaki M  Kobayashi J  Ohta M  Kamata S  Kumagai K 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2003,65(8):899-906

To investigate the pathological role of staphylococcal enterotoxins (SEs) and toxic shock syndrome toxin-1 (TSST-1) in bovine mastitis, the production of SEs and TSST-1 was investigated in staphylococci isolated from 120 mammary gland secretions (MGS, 51 from no clinical sign-mammary glands and 69 from staphylococcal mastitic-mammary glands) collected from dairy farms where staphylococcal mastitis frequently occurred in Miyagi and Yamagata prefectures from 1997 to 1998. Concentrations of these toxins and specific antibody titers in each MGS were also measured. Furthermore, SEC and TSST-1 were inoculated into lactating mammary glands and inflammatory responses were analyzed. A high percentage of staphylococci including Staphylococcus aureus and coagulase-negative staphylococci isolated from both no clinical sign- and mastitic-MGS produced both SEC and/or TSST-1. The concentration of SEC increased with the severity of the mastitis, and was significantly higher (P<0.05) in acute mastitic-than in no clinical signs-MGS. Titers of specific antibodies to TSST-1 in MGS were significantly higher (P<0.05) than those to SEC, regardless of whether or not the cows were lactating or mastitic. Specific antibodies purified from MGS neutralized each toxin in vitro. A significant increase (P < 0.05) in somatic cell counts was induced by the intramammary inoculation of SEC but not TSST-1. These findings indicated that SEC rather than TSST-1 plays an important role in the pathology of staphylococcal bovine mastitis. The inflammatory activity of TSST-1 was probably neutralized by specific antibodies in MGS.  相似文献   

Hepatocyte growth factor transduces different intracellular signals in aortic and umbilical venous endothelial cells   总被引：1，自引：0，他引：1  

Makondo K  Kimura K  Kitamura T  Yamaji D  Saito M 《The Japanese journal of veterinary research》2003,51(2):105-112

Endothelial cells are important for maintenance of vascular integrity by producing a variety of bioactive molecules such as nitric oxide (NO). Recent evidence has suggested that there are some differences in characteristics between endothelial cells from different origins. Here we examined responses of two typical endothelial cells to hepatocyte growth factor (HGF), which induces endothelium-dependent relaxation of microvessels. Stimulation of human umbilical vein endothelial cells (HUVEC) and bovine aortic endothelial cells (BAEC) with HGF increased endothelial NO synthase activity, accompanied with an increase of activity-related site-specific phosphorylation of protein kinase B/Akt. However, HGF stimulated phosphorylation of p38 mitogen-activated protein kinase (MAPK) only in HUVEC, but not in BAEC, while it induced phosphorylation of p44/p42 MAPK in both cells. These results suggest that HGF transduces different intracellular signals between aortic and umbilical venous endothelial cells, and that the differences might represent divergent endothelial responses to growth factors, especially those that activate receptor-tyrosine kinases.  相似文献   

Cloning of canine 21-hydroxylase gene and its polymorphic analysis as a candidate gene for congenital adrenal hyperplasia-like syndrome in Pomeranians     

Takada K  Kitamura H  Takiguchi M  Saito M  Hashimoto A 《Research in veterinary science》2002,73(2):159-163

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