Distribution of a fish pathogen Listonella anguillarum in the Japanese flounder Paralichthys olivaceus hatchery     

Hirotaka Mizuki  Tetsuo Morita  Haruo Sugita 《Aquaculture (Amsterdam, Netherlands)》2006,261(1):26-32

The present study was undertaken to investigate the distribution of Listonella anguillarum in a Japanese flounder (Paralichthys olivaceus) hatchery. A total of 2704 isolates were obtained from the developing fish, live diets and artificial feeds of Japanese flounder and their rearing water, 439 of which were identified as L. anguillarum by the combining incubation on thiosulfate-citrate-bile salt-sucrose (TCBS) agar at 35 °C overnight with polymerase chain reaction (PCR) detection for the VAH1 hemolysin gene. L. anguillarum was detected in all seven rotifer samples, with densities of 2.5 × 10³ to 4.6 × 10⁶ colony forming units (CFU) g^− 1. Both the analyzed samples of Nannochloropsis oculata contained this bacterium at densities of 1.6 × 10⁴ to 1.4 × 10⁵ CFU g^− 1. L. anguillarum was detected in only one of four samples of Artemia nauplii with a density of 4.8 × 10⁵ CFU g^− 1 (35%) and it was not detected in the two analyzed artificial feed samples. L. anguillarum was detected in 11 of 18 specimens of larval and juvenile Japanese flounder at densities of 5.0 × 10¹ to 7.4 × 10⁵ CFU g^− 1, while it was not detected in the two analyzed egg specimens of Japanese flounder. These results indicate that L. anguillarum associated with the developing Japanese flounder is likely derived from rearing water and live diets such as rotifers. Further, it is strongly suggested that L. anguillarum is a transient bacterium of the intestinal microflora for the Japanese flounder but is a permanently indigenous one for the Japanese flounder hatcheries.  相似文献   

Epidemiological Study and Control Trial of Taeniid Cestode Infection in Farm Dogs in Qinghai Province,China     

Zhihong GUO  Wei LI  Mao PENG  Hong DUO  Xiuying SHEN  Yong FU  Takao IRIE  Tiantian GAN  Yumi KIRINO  Tetsuo NASU  Yoichiro HORII  Nariaki NONAKA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2014,76(3):395-400

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Contamination of Poultry Products with Listeria monocytogenes at Poultry Processing Plants     

Yoshimasa SASAKI  Mika HARUNA  Mariko MURAKAMI  Mizuho HAYASHIDA  Nao TAKAHASHI  Tetsuo URUSHIYAMA  Kazuo ITO  Yukiko YAMADA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2014,76(1):129-132

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Thyroid hormone deficiency in abnormal larvae of the Japanese flounder <Emphasis Type="Italic">Paralichthys olivaceus</Emphasis>   总被引：1，自引：0，他引：1  

Nozomi?OkadaEmail author  Tetsuo?Morita  Masaru?Tanaka  Masatomo?Tagawa 《Fisheries Science》2005,71(1):107-114

ABSTRACT:   In large-scale rearing of juveniles of the Japanese flounder Paralichthys olivaceus, a certain morphological abnormality occurred spontaneously in 4% of the fish. These fish showed a slight but clearly different appearance from any developmental stage of this species, and did not settle when all the other juveniles in the same tank completed metamorphosis and had settled. From comparisons of external and internal structures between the normal and the abnormal fish, the abnormality was attributed to unbalanced progress of metamorphosis, mainly due to metamorphic stasis. The thyroid of the abnormal fish was apparently activated morphologically. In addition, serum thyroxine (T4) concentrations in the abnormal fish were reduced to less than 1/10 of that of normal fish. After 14 days of T4 treatment (0.1 p.p.m) of the abnormal fish, all the abnormal characteristics disappeared, and the fish recovered to normal, suggesting normal responsiveness to thyroid hormones in peripheral tissues, whereas thiourea treatment (30 p.p.m., 14 days) further delayed metamorphosis. These results suggest that these abnormal fish were suffering from thyroid hormone deficiency, and were unable to secrete a sufficient amount of thyroid hormone to complete metamorphosis.  相似文献   

Changes in estrogen receptor expression in the chick thymus during late embryonic development     

Masafumi Katayama  Tomokazu Fukuda  Toshimitsu Hatabu  Kiyoaki Narabara  Asaki Abe  Yasuhiro Kondo 《Animal Science Journal》2014,85(3):277-285

In chickens, although estrogen receptors (ER) are reported to be associated with the immunological processes, detailed information about the differences in ER expression in the tissues related to the development of lymphocytes is not fully known, especially during the developmental stage. To learn more about this immunological relationship, we used semi‐quantitative polymerase chain reaction method to detect the ER expression levels in the thymus tissues of chicks during the developmental stage. Furthermore, ER‐expressing cells were detected by immunohistochemistry. The results of this study show that the expression level of ER increased on embryonic day 16 and decreased on day 20. Furthermore, ER expression was significantly higher in male than in female chickens at day 16. The increased expression on day 16 and decreased level on day 20 were also reproduced in the incidence of immunoreactive cells, although there was a 1‐day delay in the elevated incidence of the cells. This study revealed the changes in ER expression and the incidence of ER‐positive cells in the thymus of chickens during the developmental stage.  相似文献   

Interannual variability of the ecosystem of the Kii Channel, the Inland Sea of Japan, as influenced by bottom intrusion of cold and nutrient-rich water from the Pacific Ocean, and a recent trend of warming and oligotrophication   总被引：2，自引：0，他引：2  

Koji Ozaki  Shin-Ichi Uye  Teruichi Kusumoto  Tetsuo Hagino 《Fisheries Oceanography》2004,13(1):65-79

Interannual variability of the ecosystem of the Kii Channel, productive shelf water on the Pacific side of south‐western Japan, was analysed based on physicochemical environmental variables and abundance of major zooplankton taxa collected monthly for 12 yr from 1987 to 1999. The Kii Channel experienced both short‐term (i.e. 3–4 yr) cyclical changes and a long‐term (i.e. decadal) environmental trend. The short‐term variability was primarily associated with year‐to‐year differences in intrusion of subsurface, cold nutrient‐rich water along the bottom of the Kii Channel from the Pacific Ocean. When this bottom intrusion was intense, the Kii Channel experienced a cold, new production‐dominated ecosystem. The bottom intrusion, however, has become less intense in recent years, because of the closer proximity of the Kuroshio flow axis to the Kii Channel. Hence, there was a consistent trend towards warming and a regenerated production‐dominated ecosystem. In accordance with such environmental changes, the zooplankton community shifted towards more oceanic conditions; major herbivorous calanoids (i.e. Calanus sinicus, Paracalanus parvus (s.l.), Clausocalanus spp. and Acartia omorii) decreased, while carnivores (i.e. hydromedusae and Sagitta spp.) increased. The amount of total fish catch also decreased, while the catch of subtropical species increased. These findings lead us to conclude that the bottom intrusion from the Pacific Ocean plays a key role in determining the biological production in the Kii Channel.  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   

All-male Tilapia Hybrids of Two Strains of Oreochromis niloticus     

Nilton G.  Marengoni Yoshio  Onoue Tetsuo  Oyama 《Journal of the World Aquaculture Society》1998,29(1):108-113

Hybridization between Nile tilapia Oreochromis niloticus (Local and Stirling University strains) and blue tilapia O. aureus was found to be a tool to produce monosex populations. In order to select a purebred that produces all- or nearly all-male hybrids with high productivity, O. niloticus females and their diploid gynogenetics (meiogynes and mitogynes) were hybridized with O. aureus males. The sex ratio of progenies was evaluated from inter- and intraspecific crosses of two strains of Nile tilapia. Single-pair matings and group spawns under hatchery conditions showed no deviation ( P > 0.01) from the expected sex ratio of intraspecific crosses among two strains of Nile tilapia. However, a higher proportion of male progenies in blue tilapia was observed in group spawns in pond ( P < 0.004) and hatchery conditions ( P < 0.01). Only the Stirling strain and mitogynes produced all-male progenies under laboratory conditions. There were significant differences ( P < 0.05) in growth among hybrid progeny groups, when gynogens and their regular O. niloticus (Local strain) females were crossed with O. aureus males. Six-month hybrid offspring from mitogyne female parents grew better than those from regular and meiogyne female broods.  相似文献   

Production of aromatic amino acids and related compounds from p-hydroxyphenylacetic acid by rumen microorganisms in vitro     

Rokibul Islam KHAN  Sada ANDO  Toshihiro TAKAHASHI  Tetsuo MORITA  Ryoji ONODERA 《Animal Science Journal》2003,74(4):313-319

Suspensions of mixed rumen bacteria (B), protozoa (P), and mixed rumen microorganisms (BP) prepared from rumen contents of fistulated goats were anaerobically incubated with 1 mM p‐hydroxyphenylacetic acid (HPA) at 39°C for 24 h. Tyrosine (Tyr), phenylalanine (Phe), tryptophan (Trp) and other related compounds in both supernatants and hydrolyzates of microbial cells in all incubations were analyzed by HPLC. Large amounts of Tyr (32.1, 42.7 and 36.1% of disappeared HPA in B, P and BP, respectively) were produced from HPA during a 12 h incubation period. The formation of Tyr in P (178.6 µmol/g MN) was 1.5 and 2 times higher than in B and BP, respectively. Phe (7–11% of the disappeared HPA) and Trp (3–6% of the disappeared HPA) were also synthesized from HPA in B, P, and BP. Phe synthesis in P (46.3 µmol/g MN) was 1.7 times higher than in B but, in contrast, Trp synthesis in B, was 1.6 times higher than in P. The metabolites p‐hydroxyphenylpyruvic acid (in the range of 5–14% of disappeared HPA), phenylacetic acid (1–11%), p‐hydroxybenzoic acid (3–7%) and benzoic acid (1–6%) were produced from HPA in B, P and BP. Phenylpropionic acid (6% of the disappeared HPA) was produced only in B and BP.  相似文献   

Positive chronotropic and ruminolytic actions of adenosine in goat     

M Fukuda  T Hayama 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1985,47(5):849-850

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