Phospholipase A<Subscript>1</Subscript> activity of crude enzyme extracted from the ovaries of skipjack tuna     

Seiichi Hiratsuka  Tomoko Kitagawa  Kouta Yamagishi  Shun Wada 《Fisheries Science》2008,74(1):146-152

The phospholipid class composition, fatty acid composition and phospholipase A₁ (PLA₁) activity from the ovaries of skipjack tuna were compared with those of six other species of marine fish. In the skipjack ovaries, the lysophosphatidylcholine (LPC) proportion for the phospholipid, the docosahexaenoic acid (DHA) percentage for the total fatty acids of the phospholipids and the PLA₁ activity of the crude enzyme were the highest among those of the seven species. The optimum pH and temperature for the PLA₁ activity of the crude enzyme from the skipjack ovaries were in the range of pH 6–7 and 20–30°C, respectively, and calcium ions were not required. As a substrate, phosphatidylcholine was more easily hydrolyzed than phosphatidylethanolamine by this enzyme, and the plasmalogen-type phospholipid was much lower than the acyl-type phospholipid. After a 6-h hydrolysis reaction of the purified phospholipid extracted from the mixed ovaries of skipjack and yellowfin tuna by this enzyme, the LPC ratio of the phospholipid increased from 20 to 72.6% and the percentage of DHA for the total fatty acids of the phospholipid also increased. Thus, skipjack ovaries might possibly be used as a source of PLA₁.  相似文献   

Spatial variability in the growth of direct-seeded rainfed lowland rice (Oryza sativa L.) in northeast Thailand     

Satoshi Hayashi  Akihiko Kamoshita  Junko Yamagishi  Anuchart Kotchasatit  Boonrat Jongdee 《Field Crops Research》2009

Large within-field variation in rice growth often causes production loss in broadcast-seeded (BC) rainfed lowland rice. The spatial variability of direct-seeded rainfed lowland rice was evaluated in 2004, 2005, and 2007 in on-station experiments at Ubon Ratchathani, northeast Thailand, in relation to soil water content and weed infestation, by adopting semivariogram and block kriging, including comparisons among BC with harrowing (BCH; no weeding), BC with no harrowing (BCNH; no weeding), and row-seeded (RS; interrow weeding once) fields. BCH and BCNH were also compared in 11 farmers’ fields in 2006 and 2007, to assess the effect of harrowing on rice growth and weed infestation. During most of the rice growing periods, flooded and non-flooded portions existed simultaneously in the fields, with different proportions among years and among seeding methods in the on-station experiment. BCH and BCNH rice had large within-field variation in seedling density, heading date, shoot dry matter, grain yield, harvest index, panicle density, and filled spikelet per panicle, as well as in weed infestation, measured by a quick visual estimation. Many of the measured variables (except mean soil water content in RS in 2007, seedling density in BCH in 2005 and 2007, shoot dry matter in BCH and BCNH in 2007, and panicle density in BCH in 2007) were spatially dependent (i.e., data from nearby locations were most similar) by geostatistical analysis. Analysis of correlations using the 420 data sets of BCH plots in 2005 and BCH, BCNH, and RS plots in 2007 revealed a positive correlation between soil water content and grain yield and negative correlations between weed infestation and soil water content and grain yield. Compared with BCH, in 2007 BCNH had much lower grain yield because of lower soil water content after establishment and more weed infestation. BCH had higher grain yield than BCNH in weedy fields in the farmers’ fields experiment. RS with interrow weeding resulted in a smaller coefficient of variation, smaller sill value, and higher grain yield than BCH, due to less weed infestation and a higher proportion of flooded water. These results indicated that reducing the spatial variability in rice growth requires careful field preparation, such as harrowing to level the soil surface and to reduce the uneven distribution of standing water and the variability in soil water content, combined with effective crop and weed management (i.e., harrowing and row-seeding). This is the first study that examined spatial variability in the growth of direct-seeded rice as a function of soil water content and weed infestation in a rainfed lowland environment.  相似文献   

Pathological changes in the myocardium of hypocalcaemic parturient cows     

Yamagishi N  Ogawa K  Naito Y 《The Veterinary record》1999,144(3):67-72

Three parturient cows in lateral recumbency which were moaning and had tachycardia, arrhythmia and dyspnoea were thoroughly examined. They were hypocalcaemic (0.70-1.27 mmol/litre) and were euthanized within four days, because they failed to respond to calcium treatment. By light microscopy the most characteristic pathological changes in the heart were necrotic changes scattered throughout the myocardium. Electron microscopy revealed abnormalities in the myocytes which were characterised by focal myofibrillar lysis, irregular splitting, streaming and spreading of the Z band and myofibrillar disarray.  相似文献   

The N-Terminal Region of the Readthrough Domain Is Closely Related to Aphid Vector Specificity of Soybean dwarf virus     

Terauchi H  Honda K  Yamagishi N  Kanematsu S  Ishiguro K  Hidaka S 《Phytopathology》2003,93(12):1560-1564

ABSTRACT It has been speculated that the N-terminal half of the readthrough domain (RTD) encoded by open reading frame 5 of Soybean dwarf virus (SbDV) is related to the vector specificity. To further investigate this hypothesis, transmissibility via aphids was tested on 17 SbDV isolates and comparisons of the deduced amino acid sequences of the coat protein (CP) and other proteins encoded by the RTD were made between these isolates. Isolates were distinguished into four strains: YS, causing yellowing in soybean and transmittable by Aulacorthum solani; DS, causing dwarfing and transmittable by A. solani; YP, causing yellowing and transmittable by Acyrthosiphon pisum; and DP, causing dwarfing and transmittable by A. pisum. Phylogenetic analysis showed that the trees for the CP and the C-terminal half of the RTD sequences contained clusters of isolates of the same symptom type, whereas the tree for the N-terminal half of the RTD contained clusters of isolates of the same aphid vector type. These results agreed with our previous data of the complete nucleotide sequences of four SbDV isolates, and strongly indicated a close relationship between the N-terminal half of the RTD amino acid sequences and aphid transmission specificity of SbDV.  相似文献   

Cerebellar ataxia due to Toxocara infection in Mongolian gerbils,Meriones unguiculatus   总被引：3，自引：0，他引：3  

Akao N  Tomoda M  Hayashi E  Suzuki R  Shimizu-Suganuma M  Shichinohe K  Fujita K 《Veterinary parasitology》2003,113(3-4):229-237

We assessed the usefulness of gerbils as an experimental model for neurologic toxocarosis. Mongolian gerbils, Meriones unguiculatus, infected with Toxocara canis or Toxocara cati (1000 eggs/gerbil) showed progressive neurologic disorders from 50 days after infection in T. canis-infected gerbils or from 120 days after infection in T. cati-infected gerbils. The incidence of the onset was 6 of the 13 gerbils (49%) in the T. canis-gerbils and 5 of the 7 gerbils (71%) in the T. cati-gerbils. Histopathologically, the cerebellum was the most affected in both groups. We observed loss of Purkinje cells, glial nerve fibers, and nerve sheaths. We also found foci consisting of aggregated macrophages scattered in the white matter of the cerebellum. The affected gerbils showed ataxia and ultimately died of cachexia. Our findings suggest that irreversible neurologic toxocarosis in gerbils can be induced by infection with either T. canis or T. cati.  相似文献   

An immunohistochemical study of endocrine cells in the abomasum of vagotomized calf     

Soehartono RH  Kitamura N  Yamagishi N  Taguchi K  Yamada J  Yamada H 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2002,64(1):11-15

The effect of thoraco-vagotomy on the distribution and frequency of chromogranin-, serotonin-, somatostatin- and gastrin-immunoreactive cells in the abomasum of the calf were investigated by immunohistochemistry. Calves were vagotomized at 1 week old and sampled 2 and 4 weeks later. The endocrine cells generally decreased in number in vagotomized calves as compared to non-operated control calves. However, the detailed responses of endocrine cells to vagotomy varied depending on the endocrine cell type, region of gastric mucosa, and period after vagotomy. The present result suggests that the vagus nerve has an influence on the intrinsic regulatory system by endocrine cell control in the ruminant abomasum.  相似文献   

Effects of oral administration of "rumen-bypass" vitamin D3 on vitamin D and calcium metabolism in periparturient cows     

Yamagishi N  Dohmae H  Shirato A  Sato J  Sato R  Naito Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2000,62(4):403-408

Eleven late-pregnant Jersey cows were assigned to two groups; a group (PO-RBVD group) consisting of five cows treated with an oral administration of 10 million I.U. of an encapsulated form of vitamin D3 ("rumen-bypass" VD3; RBVD3) and another group (IMVD group) consisting of the other six treated with an intramuscular injection of 10 million I.U. of vitamin D3 (VD3). The cows received the RBVD3 or VD3 administration at 7 days before the expected parturition. The changes in the plasma concentrations of vitamin D metabolites, ionized Ca (Ca++) and inorganic phosphorus (iP) were evaluated. Of the vitamin D metabolites, the plasma 25-hydroxyvitamin D concentrations in PO-RBVD group increased significantly after the RBVD3 administration and remained in high levels that were significantly higher than those in IMVD group. This suggested that RBVD3 was absorbed rapidly and excellently from the post-ruminal digestive tract without the degradation by ruminal microorganisms. The plasma Ca++ and iP concentrations in PO-RBVD group tended to be higher after the administration and around parturition than those in IMVD group. From these observations, it was suggested the oral RBVD3 administration had more potent ability to prevent parturient paresis compared with the VD3 injection used widely in Japan.  相似文献   

Pathological evaluation of host-specific AAL-toxins and fumonisin mycotoxins produced by Alternaria and Fusarium species     

Daisuke Yamagishi  Hajime Akamatsu  Hiroshi Otani  Motoichiro Kodama 《Journal of General Plant Pathology》2006,72(5):323-327

Host-specific AAL-toxins and mycotoxin fumonisins are structurally related and were originally isolated from the tomato pathotype of Alternaria alternata and from Fusarium verticillioides, respectively. Previous reports on the production of fumonisin derivatives by the tomato pathotype suggested a possible involvement in the pathogenicity of the pathogen. Here, we have evaluated the role of fumonisin in A. alternata–tomato interactions. The results indicate that highly pathogenic isolates of A. alternata tomato pathotype produce AAL-toxin as the sole toxin, strongly implicating it as a pathogenicity factor. The related compound, fumonisin, is also toxigenic and has infection-inducing activity on susceptible tomato plants.  相似文献   

The relation between pathogenicity and plaque size of Getah virus Kanagawa strain in suckling mice     

T Hohdatsu  N Takahasi  S Ide  H Yamagishi  H Saito  Y Fujisaki  H Koyama 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1990,52(3):519-526

The relation among biological properties, particularly pathogenicity for suckling mice, and plaque size was studied in four virus strains: Getah virus strain Kanagawa; two strains obtained by plaque cloning of the Kanagawa strain, Getah Kanagawa SP (G-K-SP) strain which forms small plaques (SP) only and strain G-K-LP which forms large plaques (LP) only; and strain Haruna which forms SP only. There were no marked differences among the four strains in serological properties, growth curves and sensitivity to pH, trypsin and temperature. Strain G-K-LP showed higher pathogenicity for suckling mice than strain G-K-SP. However, the pathogenicity of strain Haruna, which forms SP only, was as high as that of strain G-K-LP. Some of the clones in SP of strain Kanagawa kill all mice in 5 to 6 days after inoculation while the others required 9 to 11 days or longer before causing death. The present study showed that the pathogenicity of Getah viruses shortly after being isolated from the field, such as the Kanagawa strain, is different between large and small plaques, and even among small plaques, at least in suckling mice, and that the pathogenicity has no relation to plaque size.  相似文献   

The duality of teleost gonadotropins   总被引：5，自引：0，他引：5  

Hiroshi Kawauchi  Kunimasa Suzuki  Hiromichi Itoh  Penny Swanson  Nobuko Naito  Yoshitaka Nagahama  Masumi Nozaki  Yasumitu Nakai  Seiga Itoh 《Fish physiology and biochemistry》1989,7(1-6):29-38

The duality of salmon gonadotropins has been proved by biochemical, biological, and immunological characterization of two chemically distinc gonadotropins. GTH I and GTH II were equipotent in stimulating estradiol production, whereas GTH II appears to be more potent in stimulating maturational steroid synthesis. The ratio of plasma levels and pituitary contents of GTHs and the secretory control by a GnRH suggest that GTH I is the predominant GTH during vitellogenesis and early stages of spermatogenesis in salmonids, whereas GTH II is predominant at the time of spermiation and ovulation. GTH I and GTH II are found in distinctly separate cells. In trout, GTH I is expressed first in ontogeny, whereas GTH II cells appear coincident with the onset of spermatogenesis and vitellogenesis, and increase dramatically at the time of final reproductive maturation. Comparison of the amino acid sequences of polypeptides and the base sequences of cDNA revealed that salmon GTH I β is more similar to bovine FSHβ than bovine LHβ and salmon GTH II β shows higher homology to bovine LHβ than to bovine FSHβ. The existence of two pituitary gonadotropins in teleosts as well as tetrapods suggests that the divergence of the GTH gene took place earlier than the time of divergence of teleosts from the main line of evolution leading to tetrapods.  相似文献