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排序方式: 共有60条查询结果,搜索用时 31 毫秒
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Carlos Yanes‐Roca Mayra E. Toledo‐Cuevas Lizbeth J. Sánchez Ana Born‐Torrijos Nicole Rhody Kevan L. Main 《Journal of the World Aquaculture Society》2018,49(3):612-624
Black snook, Centropomus nigrescens, have been identified as a promising candidate for aquaculture although, like many of the Centropomid species, high mortality associated with early larval stages presents a significant bottleneck to their commercialization. The digestive capacity of black snook larvae throughout the first 37 d after hatch (d.a.h.) was evaluated by quantifying digestive enzyme activities using biochemical techniques. Results showed that black snook larvae have alkaline proteases at hatching, which are known to be important during the first days of feeding for digestion. Toward the end of the study, acid proteases concentration increased (37 d.a.h.). Enzymes for lipid digestion, pancreatic lipase and bile salt‐activated lipase, were already present in the larvae before exogenous feeding commenced, and their activity increased with age and growth (length). Intracellular digestion, measured as the activity of leucine‐alanine peptidase, was high early on (5 d.a.h.) and decreased as development progressed (next 32 d). In contrast, alkaline phosphatase activity was lowest at first feeding and subsequently increased with age. Overall patterns in enzyme activity suggest the possibility of live feed weaning before 32 d.a.h. if artificial diets can be properly balanced. 相似文献
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Classification of Dutch and German avian reoviruses by sequencing the sigma C protein 总被引:1,自引:0,他引:1
Kant A Balk F Born L van Roozelaar D Heijmans J Gielkens A ter Huurne A 《Veterinary research》2003,34(2):203-212
We have amplified, cloned and sequenced (part of) the open reading frame of the S1 segment encoding the sigma C protein of avian reoviruses isolated from chickens with different disease conditions in Germany and The Netherlands during 1980 up to 2000. These avian reoviruses were analysed phylogenetically and compared with sequences of avian reoviruses in the Genbank database. The avian reoviruses could be grouped in 5 different genotyping clusters and this classification was identical when the sequences were compared of the 5' end, the 3' end or the whole open reading frame of the sigma C protein. Therefore sequencing of either part of the gene encoding the sigma C protein seems to be reliable for classification. We were unable to identify a correlation between sigma C sequences of the avian reoviruses and the disease condition they were isolated from. The sequences found in The Netherlands and in Germany are, like those in Taiwan, more dispersed than the known avian reovirus sigma C sequences in the USA and Australia. We did not establish temporal or geographic differences in the avian reoviruses studied. 相似文献
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Two hundred feral cats from the inner suburbs of Sydney were examined post mortem for adult Dirofilaria immitis and circulating microfilariae, and 101 of these cats were tested for heartworm antigens by an ELISA. Only 2 cats (1%) had adult heartworms, the blood sample from another cat contained a single microfilaria. The blood of a further three cats contained small amounts of D immitis antigen. Although D immitis occurs in cats in Sydney, the prevalence is not high enough to warrant prophylactic treatment. 相似文献
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Wänke H Begemann F Vilcsek E Rieder R Teschke F Born W Quijano-Rico M Voshage H Wlotzka F 《Science (New York, N.Y.)》1970,167(3918):523-525
Analytical data for 42 major and trace elements were mostly obtained by a combination of instrumental and radiochemical neutron activation analyses using both thermal and 14-million-electronvolt neutrons. Excesses of nitrogen and chlorine in the fines, compared with the rocks, are attributed to the solar wind. A striking similarity for contents of seven elements in lunar metal and metal from the calcium-rich achondrite Juvinas was noted. Fractional dissolution was used to separate five radionuclides produced by cosmic-ray bombardment in the fines and rock 57-40. Results for argon-39 from the reaction potassium-39 (n,p), and for argon-37, from the reaction calcium-40 (n,a), seem to require a neutron spectrum conitaining more neutrons below 2 million electronvolts than the evaporation spectrum or that given by Arnold, Honda, and Lal (1) or a strong time dependence for the neutron flux. 相似文献
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Born M 《Science (New York, N.Y.)》1955,122(3172):675-679