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Hiroshi ISEKI Michihiro TAKAGI Kenji KAWASHIMA Tomoyuki SHIBAHARA Yoshiko KURODA Hiroshi TSUNEMITSU Makoto YAMAKAWA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(12):1663-1666
To clarify the pathogenicity of Japanese type 1 porcine reproductive and respiratory
syndrome virus (PRRSV) isolate in experimentally infected pigs, we evaluated clinical
signs and monitored viremia for 21 days post-inoculation (dpi). Lungs were mottled, tanned
and reddish in appearance; had lesions predominantly in the cranial, middle and accessory
lobes; and failed to collapse at 10 dpi. Although microscopic lesions of lungs were
reproduced using the Japanese emerging type 1 PRRSV isolate under experimental conditions,
no significant differences were noted between the challenge and control groups regarding
mean rectal temperature and daily weight gain. These results provide useful insights into
the limited pathogenicity of single infection with the Japanese type 1 PRRSV isolate in
piglets, which differ from findings in reported field cases. 相似文献
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ABSTRACT: The parasite fauna of Mustelus manazo from seven localitiesin Japan and Taiwan was assessed for the feasibility of using parasitesas biological tags for the identification of different host stocks.Examination of 1038 host specimens resulted in 13 parasite speciesrecorded: one nematode, two myxosporeans, two copepods and eightcestodes. Although relatively low overall prevalence of the firstfive species at different localities showed some significant differences,the samples collected in Tokyo Bay bore the lowest similarity (19.2%).These results support previous studies, which suggested the existenceof a unique host stock in Tokyo Bay. Accordingly, combinations ofprevalence data may provide useful information on stock identification.Cestodes probably have the greatest potential for use as biologicaltags. Detailed examination of 25 specimens of M . manazo fromAomori and Tokyo Bay disclosed eight species of intestinal cestodes.A canonical discriminant analysis based on these species separatedthe two localities clearly. 相似文献
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MINORU ICHIHARA HIDEHIRO INAGAKI KAZUO MATSUNO CHIEKO SAIKI MASAYUKI YAMASHITA HITOSHI SAWADA 《Weed Biology and Management》2012,12(3):131-135
The potential impact of postdispersal seed predation by the field cricket, Teleogryllus emma (Ohmachi et Matsuura), on the seedling emergence of Italian ryegrass (Lolium multiflorum Lam.), a non‐native grass weed in Japan, was determined. The relationship between cricket density and the proportion of seedling emergence was investigated by conducting manipulative experiments in duplicate, using enclosures. One‐thousand seeds of Italian ryegrass were exposed to adult crickets at different densities (zero, one, two, four and eight individuals per 2.25 m2 enclosure) for 2 weeks. The proportion of seedling emergence decreased with increasing cricket density. The proportion of seedling emergence in the enclosures without the crickets was 90.9–97.2%, whereas the seedling emergence in the enclosures with eight crickets greatly decreased, to 0.5–2.5%. These results suggest that postdispersal seed predation by T. emma can substantially decrease the abundance of Italian ryegrass at an early life stage and reduce its population in environments with a high density of crickets. 相似文献
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Spatial patterns in the distribution and abundance of Japanese anchovy, Engraulis japonicus, eggs were studied from net surveys in the East China Sea in May 1991. Egg abundance was> 5 × 103 eggs (100 m3)?1 in the area off Changjiang River, where a large spawning ground was developed. The vertical distribution of living eggs showed a maximum concentration at the surface (40700 eggs (100 m3)?1) and rapidly decreased to ~5000 eggs (100 m3)?1 at 14 m. Newly spawned eggs (stage I) were found throughout the water column but were most abundant near surface. Some eggs were morphologically identified as dead owing to their abnormal development and physical damage. In contrast to living eggs, no dead eggs were found at the surface and the concentrations were low to 21 m depth (40–64 eggs (100 m3)?1). The concentration increased markedly with increasing depth, reaching a maximum of 634 eggs (100 m3)?1 near the bottom (35 m). Dead eggs accounted for less than 0.3% of the total caught within 7 m of the surface and increased exponentially to 12% near the bottom. The settling loss of dead anchovy eggs also was studied by employing sediment traps at the spawning ground. The downward flux of settling eggs was low (304–405 eggs m?2 day?1) at 15 and 20 m depths, but rapidly increased with increasing depth, reaching a maximum of 1622 eggs m?2 day?1 at 35 m (5 m above bottom). By comparing the egg flux at 20 m with the living eggs abundance in the upper 20 m, the settling loss of eggs was calculated as about 0.098 day?1. This probably represents the natural mortality of anchovy eggs caused by genetic abnormalities and incomplete fertilization. 相似文献
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使用12个分别持有不同抗病基因(Xa1,Xa2,Xa3,Xa4,Xa5,Xa7,Xa8,Xa10,Xa11,Xa13,Xa14和Xa21)的近等基因系水稻白叶枯病鉴别品种及3个对照品种(IR24,Toyonishiki和Sigadagabo),鉴别了从云南省收集的138个菌株。结果根据致病谱可以将这些菌株分成A-J共10组。A组菌株仅对Toyonishiki和Sigadagabo两个对照品种致病,J组菌株则能对9个鉴别品种和3个对照品种致病。对不同海拔采集的菌株进行致病力分析的结果表明,从大理、武定等较高海拔粳稻种植区采集的菌株致病力较弱,在鉴别品种上病斑的平均长度不到50mm;而元江、景洪、潞西等低海拔杂交稻种植区采集的菌株致病力较强,在鉴别品种上的病斑平均长度超过100mm。从高海拔稻区到低海拔稻区,病菌致病力有逐步增强的趋势。 相似文献
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Bidjokazo FOFANA Leonides HALOS-KIM Mercy AKEREDOLU Ande OKIROR Kebba SIMA Deola NAIBAKELAO Mel OLUOCH Fumiko ISEKI 《农业科学与工程前沿(英文版)》2020,7(4):418-426
The value chain extension strategy of Sasakawa Africa Association focuses on improving the capacity of national agricultural extension systems and follows various thematic areas along the value chain to address key challenges accountable for low income households and poverty in Africa. Farmer learning platform is a model designed to increase crop productivity and encompasses demonstration plots where technological packages demonstrated significantly outperformed other technology plots in crop productivity and average profit margins. Enterprise-oriented production, postharvest and trading centers are value adding models designed to improve the effectiveness of extension and adoption of postharvest and agricultural processing technologies by producers. The use of the above along with necessary capacity building has facilitated the development of profitable business linkages of smallholder farmers with financial institutions and reliable market opportunities. The community association trader-trainer model is a market-oriented business approach applied in combination with other extension models. In 2018, 297 community-based commodity association trader-trainers were mobilized and capacitated to improve farmer group dynamics and developed collective input and output access and cluster aggregation centers at community level where various agricultural produces were mobilized and collectively aggregated, and valued at about 3.9 million USD. The supervised enterprise project model is an innovative agricultural extension model developed along with above models for capacity development of extension agents and transfer of technologies to smallholder farmers. Over 6000 supervised enterprise projects have been introduced into 27 universities in 12 African countries for training front-line extension officers and extension delivery to farming communities. 相似文献
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Masaji MASE Makiko GOTOU Daisuke INOUE Satoko WATANABE Hiroshi ISEKI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(3):522
Seventeen isolates of infectious bronchitis virus (IBV) were obtained from various prefectures of Japan during 2008–2019 and genetically analyzed. The IBV isolates were classified into six genetic groups, based on phylogenetic analysis of the S1 gene. The S1 genotypes were distinguishable by a newly developed restriction fragment length polymorphism (RFLP) method using three endonucleases, Hae II, Hpa I, and Fok I. Moreover, the isolates were classified into four genetic groups, based on phylogenetic analysis of the S2 gene. However, novel genetic groups based on a combination of S1 and S2 genotypes, which were undetected previously, were confirmed in this study, indicating that various recombinant IBV strains were prevalent in poultry in Japan. 相似文献
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