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961.
为了获得数量多且存活的游离青虾精子,首次采用胰蛋白酶消化日本沼虾精荚的方法,获得了游离日本沼虾的精子。通过观察游离精子形态,并经台盼蓝染色,以每克精荚所获得形态正常、结构完整且不被染色的存活精子数为依据,探究胰蛋白酶处理的最佳条件。在p H 7.1的条件下,设计三因素四水平正交试验,设置不同酶浓度(0.2%、0.4%、0.6%、0.8%)、处理时间(5 min、10 min、15 min、20 min)和处理温度(30℃、35℃、40℃、45℃),根据正交试验结果确定酶处理最佳反应条件。结果表明,酶浓度对获得游离精子影响最大,其次是处理温度和处理时间。酶处理的最适条件为:酶浓度0.8%,处理时间10 min,处理温度40℃。经优化验证试验,表明上述理论组合确为最佳组合。本研究通过酶解法获得较多数量的存活游离精子,为进一步研究日本沼虾精子提供了获得游离精子的方法。 相似文献
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Xiuxia Chen Hongshu Chi Binfu Xu Zaiyu Zheng Jia Chen Ling Ke Hui Gong 《Aquaculture Research》2019,50(10):2802-2809
This study aimed to investigate effects of bovine serum albumin immune‐stimulating complexes (BSA ISCOMs) on immune‐related genes expression, serum nonspecific immunity and disease resistance of large yellow croaker (Pseudosciaena crocea). Fish were fed diets containing 3.5 ml of BSA ISCOMs per kg feed (experimental group) or 3.5 ml of phosphate‐buffered saline per kg feed (control group) for 1 week. The liver, spleen, head‐kidney tissues were sampled for determining gene expression of myxovirus‐resistant protein (Mx), major histocompatibility complex class II alpha chain (MHC II α), tumour necrosis factor‐alpha (TNF‐α) and interleukin‐10 (IL‐10) 30 and 90 days after feeding. Also, blood samples were collected for determining activities of serum superoxide dismutase (SOD), interferon alpha (IFN‐α), TNF‐α and alkaline phosphatase (ALP). TNF‐α and MHCⅡα gene expression in the liver, spleen, head‐kidney, as well as IFN‐α, TNF‐α and ALP activities in the serum, of experimental fish were significantly higher 30 days after feeding; while only TNF‐α and MHC II gene expression in the head‐kidney remained upregulated 90 days after feeding. The cumulative mortality of the experimental fish was significantly lower than control. This study indicated that BSA ISCOMs improved the immune response and induced protective immunity in large yellow croaker. 相似文献
964.
Infection of a Myxobolus species, previously identified as Myxobolus rotundus, was detected in 182 of 7892 (2.31%) allogynogenetic gibel carp, Carassius auratus gibelio, in a closed pond culture system in China. Morphological and molecular data showed that this myxosporean is a different species from M. rotundus parasitizing Abramis brama in Europe and is thus designated as a new species, Myxobolus turpisrotundus. M. rotundus (s.l.) ex C. auratusauratus is a synonym of M. turpisrotundus. Plasmodia of M. turpisrotundus develop in the subepidermal tissues of the body surface resulting in an unaesthetic appearance and causing severe economic losses. Prevalence of infection with the myxosporean plasmodia varied seasonally, increasing in winter and decreasing in spring. Prevalence was positively correlated to host size, but no host sex‐specificity was found. No infection was observed in other fish species (grass carp, bighead carp and yellow catfish) reared in the same pond, suggesting that the parasite has a relatively strict host specificity. Plasmodia grew gradually as the parasite developed, and reached up to a maximum 5.6 mm in diameter. Plasmodia ruptured naturally to release the mature spores and host fish completely recovered with no mortality. Release of spores and regeneration of lesions were not correlated with water temperature. Histology showed that plasmodia developed sub‐epidermally, and that the wall of the plasmodia was composed of a multiple complex structure, including layers of fibroblasts, a collagenous membrane, melanophores and a layer of cup‐like cells of unknown derivation and function. The cup‐like cells are in direct contact with pre‐sporogonic stages located in the peripheral parts of the large plasmodia. No severe host inflammatory response was seen. 相似文献
965.
为了解长江口江心青草沙水库的鱼类群落结构,于2021年对该水库进行了鱼类资源调查和群落结构分析。共采集鱼类3 209尾,分属于9目13科36属46种,以鲤科淡水鱼类为主;鲢(Hypophthalmichthys molitrix)、鳙(Aristichthys nobilis)、花(Hemibarbus maculatus)、鲫(Carassius auratus)、刀鲚(Coilia nasus)、翘嘴鲌(Culter alburnus)、长蛇(Saurogobio dumerili)、花鲈(Lateolabrax japonicus)的IRI均超过1 000,为优势种;优势种生态位分析显示肉食性和杂食性鱼类在食物资源和生存环境存在较高的生态位重叠,这两种鱼类种群规模扩大受到食物、空间等资源的限制会比生态位重叠低的更大;鲢、鳙与其他鱼类生态位重叠较低,在水库内受到的食物、空间等资源的竞争较小。年度的Margalef种类丰富度指数(D)为5.70,Shannon-Wiener多样性指数(H’)为3.01,Pielou均匀度指数(J)为0.78, Simpson优势度指数(C)为0.81... 相似文献
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Lu Ningning Zhao Yunlei Wang Hongmei Chen Wei Zhao Pei Gong Haiyan Cui Yanli Sang Xiaohui Zhang Kai 《棉花学报》2019,31(3):254-262
[Objective] The objective of this study was to identify the stable quantitative trait loci (QTLs) related to Verticillium wilt resistance in cotton. [Method] In this study, a population of 111 recombinant inbred lines (RILs) strains was developed by crossing a highly resistant parental line "Changkangmian" to Verticillium wilt and the susceptible parent TM-1. The complete composite interval mapping method was adopted to detect QTLs by Verticillium wilt disease index in multiple environmental conditions and periods in Anyang and Verticillium wilt affected areas of Xinjiang. Simple sequence repeat (SSR) markers of polymorphism were screened for genetic mapping. [Result] The genetic map was constructed by 40 simple sequence repeat (SSR) markers, consisted of 12 linkage groups with total length of 212.5 centimorgan (cM). A total of six QTLs related to the resistance to Verticillium wilt were obtained. The likelihood of odd (LOD) values ranged from 2.51 to 5.55. The maximum phenotypic variation explained (PVE) 20.34%, and the minimum PVE 6.93% were recorded. Among detected QTLs, qVR-D05-1 was detected in both Verticillium wilt affected fields in Anyang and Xinjiang in July 2015 and July 2016 with PVE of 12.96% and 20.34%, respectively. [Conclusion] This study can provide a potential reference for mapping stable QTLs related to resistance to Verticillium wilt. 相似文献