Quantitative analysis of pattern of gonial proliferation during sexual maturation in Japanese scallop <Emphasis Type="Italic">Patinopecten yessoensis</Emphasis>     

Makoto Osada  Satoshi Nakamura  Akihiro Kijima 《Fisheries Science》2007,73(6):1318-1324

ABSTRACT:   This study was undertaken to describe and quantitatively analyze the pattern of development of gametes in the Japanese scallop Patinopecten yessoensis . Incorporation of 5-bromo-2'-deoxyuridine (BrdU) into gonial cells was used to quantitatively detect mitotically active gonial cells. Oogonia increased in number from November to December and decreased rapidly to March. A small number of oocytes was detected in November. Oocytes steadily increased in number and size up to March. The number of spermatogonia slightly increased from November to December, and increased markedly from January to March. Both ratios of BrdU-immunopositive gonial cells in the ovary and testis to gonial cells moderately increased from September to December. The ratio of BrdU-immunopositive spermatogonia to gonial cells drastically increased from January to February and kept an elevated level in March, whereas the oogonia started to disappear in January. The results suggest that the pattern of proliferation of gonial cells can be divided into two phases: (i) phase I, oogonia and spermatogonia slowly proliferate through the growing stage; and (ii) phase II, oogonia develop into oocytes and spermatogonia begin to proliferate rapidly through the mature and spawning stages. The proliferation of gonial cells is likely under different endocrine controls in phases I and II.  相似文献   

A retrospective evaluation of doxorubicin‐based chemotherapy for dogs with right atrial masses and pericardial effusion     

S. Ghaffari  D. C. Pelio  A. J. Lange  J. W. Arndt  J. D. Chretin  S. C. Fiocchi  D. Bianco  R. K. Nakamura 《The Journal of small animal practice》2014,55(5):254-257

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Prognostic Value of Left Atrial Function in Dogs with Chronic Mitral Valvular Heart Disease     

K. Nakamura  T. Osuga  K. Morishita  S. Suzuki  T. Morita  N. Yokoyama  H. Ohta  M. Yamasaki  M. Takiguchi 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2014,28(6):1746-1752

Background

A strong correlation between left atrial (LA) dysfunction and the severity of cardiac disease has been described in human patients with various cardiac diseases. The role of LA dysfunction in dogs with chronic mitral valvular heart disease (CMVHD) has not been addressed.

Objectives

To investigate the correlation between LA function and the prognosis of dogs with CMVHD.

Animals

Thirty‐eight client‐owned dogs with CMVHD.

Methods

Prospective clinical cohort study. Dogs were divided into 2 groups (survivors and nonsurvivors) based on the onset of cardiac‐related death within 1 year. Physical examination and echocardiographic variables were compared between the groups. For the assessment of the comparative accuracy in identifying patients with cardiac‐related death, receiver operating characteristic (ROC) curves and multivariate logistic analysis were used.

Results

The highest accuracy was obtained for the LA active fractional area change (LA‐FAC _act), with an area under the ROC curve (AUC) of 0.95, followed by the left atrial to aortic root ratio (LA/Ao), with an AUC of 0.94; peak early diastolic mitral inflow velocity (E), with an AUC of 0.85; and LA total fractional area change (LA‐FAC _total), with an AUC of 0.85. In the multivariate logistic regression analysis, LA‐FAC _act emerged as the only independent correlate of cardiac‐related death within 1 year (odds ratio = 1.401, P = .002).

Conclusions and Clinical Importance

Regarding both the size and function, the LA has a strong correlation with the prognosis of dogs with CMVHD. The most significant independent predictor of mortality in this study was LA‐FAC _act.  相似文献   

Mycobacteriosis in a Domestic Ferret (Mustela putorius furo)     

Makoto NAKATA  Yasutsugu MIWA  Masaya TSUBOI  Kazuyuki UCHIDA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2014,76(5):705-709

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Taurine transporter from the giant Pacific oyster <Emphasis Type="Italic">Crassostrea gigas</Emphasis>: function and expression in response to hyper- and hypo-osmotic stress     

Masatomi Hosoi  Chuya Shinzato  Masaya Takagi  Shoko Hosoi-Tanabe  Hideki Sawada  Eri Terasawa  Haruhiko Toyohara 《Fisheries Science》2007,73(2):385-394

ABSTRACT:   Taurine is the primary osmolyte in marine molluscs, whose cellular osmo-conforming process is vital for environmental adaptation because of a lack of osmotic homeostasis. Here, cDNA cloning and expression, and functional analyses of taurine transporter (TAUT) from the giant Pacific oyster are reported on. The deduced amino-acid sequence of oyster TAUT (oyTAUT) showed 47–51% identity to those of vertebrate TAUT, whereas identity among the vertebrates is 78–95%. Functional analysis of oyTAUT expressed in Xenopus oocytes revealed that oyTAUT has a lower affinity and specificity for taurine and a requirement for higher NaCl concentration, compared with vertebrate TAUT. Taken together with similar functional properties of TAUT from mussel, indicated by our previous study, it is possible that these functional features reflect the internal environment of the molluscs (i.e. higher taurine and NaCl concentrations). Oyster taurine transporter mRNA expression was induced by not only hyper-osmotic stress, similar to other TAUT, but also hypo-osmotic stress. It is speculated that the expression in response to hypo-osmotic stress was induced by a substantial decrease in tissue taurine content following the decrease in the internal osmolality.  相似文献   

Changes in myoglobin content and proximate compositions of the dorsal ordinary muscles of full-cycle cultured Pacific bluefin tuna Thunnus orientalis (Temminck et Schlegel) with body size     

Yasuyuki Tsukamasa  Yoshi-Nori Nakamura  Masashi Ando  Manabu Seoka  & Ken-Ichi Kawasaki 《Aquaculture Research》2007,38(2):201-205

We investigated the changes in myoglobin (Mb) content and proximate compositions of the cephalad parts of the dorsal ordinary muscles (Ce‐DOM) of full‐cycle cultured (FC) Pacific bluefin tuna [body length: 42.6–115.4 cm, body weight (BW): 1.7–38.4 kg, killed from July 2004 to October 2005]. The Mb content of Ce‐DOM increased (P<0.01) until a BW of 7.0 kg was reached. However, the Mb content of Ce‐DOM had a wide variety above a BW of 7.0 kg. On the other hand, the moisture, protein and ash contents of Ce‐DOM of FC tuna decreased (P<0.05 and 0.01) with an increase in BW. However, the lipid content of Ce‐DOM increased gradually above about a BW of 20.0 kg. Furthermore, the Mb content in protein of the Ce‐DOM of FC tuna increased with an increase in BW. These results indicated that the increase in Mb content of Ce‐DOM of FC tuna was not related to changes in proximate composition between a BW of 1.7 and 38.4 kg.  相似文献   

IMP improves water‐holding capacity,physical and sensory properties of heat‐induced gels from porcine meat     

Yukinobu Nakamura  Koshiro Migita  Akihiro Okitani  Masanori Matsuishi 《Animal Science Journal》2014,85(5):595-601

Water‐holding capacity (WHC) of heat‐induced pork gels was examined. The heat‐induced gels were obtained from meat homogenates prepared by adding nine volumes of 0.3–0.5 mol/L NaCl solutions containing 9–36 mmol/L disodium inosine‐5′‐monophosphate (IMP) or 9 mmol/L tetrapotassium pyrophosphate (KPP) to minced pork. IMP at 36 mmol/L enhanced the WHC to the same level as attained by KPP. Physical and sensory properties of heat‐induced gels were also examined. The heat‐induced gels were prepared from porcine meat homogenates containing 0.3 mol/L NaCl and 9–36 mmol/L IMP or 9 mmol/L KPP. IMP at 36 mmol/L enhanced the values of hardness, cohesiveness, gumminess and springiness, measured with a Tensipresser, and several organoleptic scores to the same level as the score attained by KPP. Thus, it is concluded that IMP is expected to be a practical substitute for pyrophosphates to improve the quality of sausages.  相似文献   

Accumulation of organotin compounds and marine birnavirus detection in Korean ascidians   总被引：1，自引：0，他引：1  

Kaoru Azumi  Shinji Nakamura  Shin-Ichi Kitamura  Sung-Ju Jung  Keisuke Kanehira  Hisato Iwata  Shinsuke Tanabe  Satoru Suzuki 《Fisheries Science》2007,73(2):263-269

ABSTRACT:   Recently, a serious disease spread extensively in aquaculture sites of the ascidian Halocynthia roretzi in Korea. To understand circumstances of ascidians in Korean aquaculture sites, residue levels of organotin compounds were analyzed, and detection of a marine birnavirus (MABV) in tissues of H. roretzi was attempted. Korean H. roretzi showed high concentrations of butyltins (mono, di, and tributyltins), especially in the gill, hepatopancreas, and digestive tract. However, there was no significant difference in the residues of butyltins in the hepatopancreas between diseased and non-diseased ascidians. The positive rate of MABV detection was high in the hepatopancreas, but also no significant difference was observed between diseased and non-diseased individuals. These observations suggest that an accumulation of tributyltin and a latency of MABV in H. roretzi tissues does not directly relate to the occurrence of the disease.  相似文献   

Treatment with an aromatase inhibitor induces complete sex change in the protogynous honeycomb grouper (Epinephelus merra)     

Ramji K. Bhandari  Mikihiko Higa  Hiroki Komuro  Shigeo Nakamura  Masaru Nakamura 《Fish physiology and biochemistry》2003,28(1-4):141-142

To study the mechanism of protogynous sex change in honeycomb grouper, the wild fish of both sexes and transitionals were collected for one year, and changes in gonadal structures and serum levels of sex hormones in each individual were examined. The onset of sex change was associated with low serum estradiol - 17β (E2) levels. In order to clarify whether E2 deprivation causes sex change, maturing females were implanted with the non-steroidal aromatase inhibitor (Fadrozole, AI). AI caused complete sex change from female to functional males in two and half months. The present results suggest that E2 is an important endogenous factor which regulates protogynous sex change in the honeycomb grouper.  相似文献   

Characterization of a cDNA encoding a homolog of actin-related protein 4 from a marine red alga Porphyra yezoensis     

Yukihiro Kitade  Michiko Nakamura  Hirotoshi Endo  Satoru Fukuda  Kazuyoshi Kuwano  Naotsune Saga 《Fisheries Science》2006,72(3):639-645

ABSTRACT:   A cDNA ( PyARP4 ) containing an open reading frame for a protein of 573 amino acids was identified in the marine red alga Porphyra yezoensis . The conceptual PyARP4 protein exhibits significant similarity to actin-related protein (ARP) 4 in the terrestrial plant Arabidopsis . Comparison of the deduced amino acid sequence showed moderate sequence identity (30%) to a conventional actin in P. yezoensis , as seen in comparisons between ARP and conventional actins of other organisms. A putative bipartite nuclear localization signal and an actin motif were found within the PyARP4 amino acid sequence. In a phylogenetic analysis, the PyARP4 was found to cluster with the ARP4 of other organisms. The expression level of PyARP4 did not change significantly among four developmental stages of life cycle and was lower than that of a conventional actin. This cDNA therefore may serve as a useful internal standard in gene expression analyses of differentially expressed genes in P. yezoensis .  相似文献