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近江牡蛎雄核发育单倍体的人工诱导 总被引：1，自引：0，他引：1
利用紫外线诱导近江牡蛎(Crassostrea rivularis)单倍体,来用强度为1 820 μW/(cm2·s)的紫外线(254 nm)分别照射卵子0 s、10 s、20 s、30 s、40 s、50 s、60 s、70 s、80 s和90 s后,使之与正常精子进行授精实验.结果发现,照射50 s的卵子能够保持较高的受精率(63.5%),该处理组的D形幼虫发生率为0,染色体检查结果显示此时单倍体率最高(50.4%),并出现"Hertwig"效应.由于有效地诱导雄核发育需要卵子遗传物质失活和保证较高的受精率,因此在强度为1 820 μW/(cm2·s)的紫外线下照射50 s是获得近江牡蛎雄核发育单倍体的最佳条件.研究还表明,受精率和D形幼虫发生率随照射时间的增加而下降,遗传失活的卵子与正常精子受精后其胚胎发育至D形幼虫前期停止. 相似文献
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利用紫外线诱导进行栉江珧(Atrina pectinata)雌核发育单倍体的研究,用强度为2 561μW/(cm2.s)的紫外线(254nm)照射不同时间的精子与正常卵子受精展开实验。结果发现随照射时间的增加,卵裂率、早期胚胎存活率和D型幼虫发生率总体呈下降趋势,遗传失活的精子与正常卵子受精后其胚胎发育至D型幼虫前期停止。经紫外线照射的精子受精后所产生的单倍体胚胎发育速度慢于正常受精所产生的二倍体胚胎,各照射组均出现非整倍体。40 s照射组中卵裂率达到51.2%,D型幼虫发生率为0,单倍体率最高,达到36.8%,出现“Hertwig效应”。由于雌核发育单倍体的有效诱导既需要精子遗传物质失活、又需要保证较高的卵裂率,因而在强度2 561μW/(cm2.s)的紫外线下照射40 s是获得栉江珧雌核发育单倍体的最佳条件。 相似文献
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紫外线照射对光棘球海胆精子遗传失活和授精能力的影响 总被引：1，自引：0，他引：1
用不同照射剂量的紫外线照射光棘球海胆的精子,然后与正常的成熟卵子授精。在照射强度为0 75mW/(h·cm2),温度22℃的条件下,照射时间为0～180s,授精率随照射时间的增加而下降,但是在110～130s内又略有回升。用遗传失活精子授精可激活卵子,其早期胚胎的成活率随照射剂量的增加依次为57%、49%、41%、20%、12 5%、48 6%、61%、30 5%、16%。从早期胚胎成活率上可以看出"Hertwig效应"的存在。观察精子遗传失活和授精激活卵子的情况,其结果是在紫外线照射强度为0 75mW/(h·cm2),照射时间为130s,精液厚度为0 1mm的条件下,精子可以完全遗传失活,用这种失活精子授精可激活卵子进行胚胎发育。 相似文献
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利用荧光显微镜观察栉孔扇贝(Chlamysfarreri)正常卵子与雄核发育卵子在减数分裂、受精过程和卵裂早期中的核相变化。雄核发育单倍体是将强度为2.8mW/(cm2·s)的紫外线照射20s的卵子与正常精子受精后得到的。结果表明,尽管紫外线照射并没有影响卵子的成熟分裂及雌性、雄性原核的形成,但它们的发生过程滞后。在第1卵裂中期,雄核发育卵子中雌性原核并不像雄性原核一样形成染色体,而是形成1个浓缩的染色质小体(DCB)。第1卵裂后期,DCB不参与核分裂。第1卵裂结束时,DCB位于2个分裂球其中之一的细胞质内或在赤道板处被分割成两部分。实验结果首次提供了栉孔扇贝雄核发育的细胞学证据。 相似文献
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紫外辐射对栉孔扇贝精子遗传失活及形态结构的影响 总被引：4，自引：2，他引：4
报道了紫外辐射对栉孔扇贝精子遗传失活及形态结构的影响。采用光照强度为800μW/cm2·s的紫外线辐射40～50s的栉孔扇贝精子,与正常的卵子受精可以得到雌核发育的单倍体胚胎。随着辐射时间的增加,受精率明显下降,且受精卵极少发育到D形幼虫。扫描电镜观察发现,辐射后部分精子的顶体膜破裂,顶体丝伸出,辐射时间越长顶体受到的破坏越严重,证明紫外辐射可以诱导精子的顶体反应;精子的鞭毛在紫外辐射过程中也会受到破坏,随着辐射时间的增加鞭毛脱落的比例也逐渐增加。推测紫外辐射导致精子结构的破坏是受精率下降的原因之一。 相似文献
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采用照射强度为1500μw/cm2的紫外线对长牡蛎(Crassostrea gigas)精子照射60s,将处理后的精子分别与长牡蛎和栉孔扇贝(Chlamys farreri)的卵子进行受精试验,受精后11.5h用浓度为60mg/L的6-DMAP对栉孔扇贝受精卵分别持续处理15、20、25、30min,运用热滴片法对各实验组进行倍性检测。结果表明,长牡蛎同源单倍体组中单倍体率为75.6%;栉孔扇贝异源单倍体组中单倍体率为14.7%,最佳药物持续处理时间为20min,其二倍体率为24.1%;异源诱导栉孔扇贝单倍体组和二倍体组中胚胎均可以发育到D形幼虫期,其单倍体组中的D形幼虫率为5.0%,20min药物加倍二倍体组D形幼虫率最高为6.1%。本实验结果为异源精子诱导栉孔扇贝雌核发育提供了诱导参数依据。 相似文献
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研究了利用6-二甲基氨基嘌呤(60μg/mL;6-DMAP)抑制第1卵裂诱导栉孔扇贝[Chlamys farreri(Jones et Pre-ston)]雄核发育二倍体的条件。雄核发育单倍体是将强度为2.8 mW/(cm2.s)的紫外线照射20 s的卵子与正常精子受精后得到的。6-DMAP不仅可以有效地抑制减数分裂,还可以有效地抑制有丝分裂;抑制第1卵裂的适宜起始时间为受精后80 min,诱导率为21.0%~22.6%。细胞学观察显示,6-DMAP抑制第1卵裂产生的雄核发育二倍体主要来源于第1卵裂中期的受精卵,由于阻止了染色体分离和原核移动,导致一个融合的二倍性雌性原核的形成;经紫外线照射的卵核在第1卵裂中期没能形成染色体,而是形成1个浓缩的染色质小体,没有参与第1卵裂后期的核分裂。尽管倍化率和D形幼虫发生率较低,但本研究证实了栉孔扇贝雄核发育二倍体人工诱导的可行性。[中国水产科学,2006,13(4):585-590] 相似文献
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冷休克诱导大鳞副泥鳅雄核发育单倍体 总被引：4，自引：0，他引：4
为探索诱导鱼类雄核发育单倍体的新方法及形成机制,以大鳞副泥鳅为研究对象,无须卵子失活,仅用冷休克诱导雄核发育单倍体,并对其后代的早期胚胎发育、染色体数目、分裂胚细胞学观察等进行了系统分析。早期胚胎发育结果显示,0℃与3℃处理组的孵化率分别为0.83%和57.42%,二者之间孵化率差异显著(P0.05),0℃和3℃处理组均表现出单倍体综合征。染色体倍性鉴定结果显示,0℃处理组染色体分布为18~27,单倍体率为81.40%,3℃处理组染色体分布为20~30,单倍体率为68.97%。分裂胚细胞学观察结果显示,3℃处理组受精后60 min,卵核和第二极体位于胚表面,有一同释放迹象。结果表明,对大鳞副泥鳅受精卵进行3℃冷休克处理60 min,可以成功诱导雄核发育单倍体,研究推测冷休克诱导大鳞副泥鳅雄核发育的细胞学机制是雌核和第二极体一同释放。 相似文献
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Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean 
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下载免费PDF全文 The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna. 相似文献
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Liping Li Rui Wang Wanwen Liang Xi Gan Ting Huang Yan Huang Jian Li Yunliang Shi Honglin Luo Ming Chen 《广西水产科技》2014,(1)
Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China. 相似文献
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In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg. 相似文献
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Iciar Martinez Amaya Velasco Ricardo Pérez-Martín Eskil Forås Michiaki Yamashita Carmen G. Sotelo 《Journal Of Aquatic Food Product Technology》2013,22(4):289-297
The purpose of this work was to evaluate the suitability of a method based on the presence of two restriction sites (for Hae III and Hindf I) in the mitochondrial NADH dehydrogenase subunit 5 (mt ND5) gene to identify Scomber species. The evaluation was performed on 144 reference and market samples by sequencing of the entire 505-bp fragment of the mt ND5 gene and of a 464-bp fragment of the Kocher fragment of the cytochrome b gene (mt Cytb). Sequence analysis of any of the two fragments allows the identification of each of the four Scomber species, but S. japonicus and S. colias had the same restriction sites at the ND5 amplicon and would not have been differentiated by this analysis. Similarly, loss of the Hae III site in some S. scombrus individuals would have misidentified them as not being Scomber. All the market products were correctly labeled except one acquired in Spain labeled as originating in the Atlantic and containing S. japonicus. 相似文献
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Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL?1 (1.25 ng well?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation. 相似文献
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Controlled infection of Poecilia reticulata Peters (guppy) with Tetrahymena by immersion and intraperitoneal injection 下载免费PDF全文
下载免费PDF全文 G Sharon M Pimenta‐Leibowitz M C L Vilchis N Isakov D Zilberg 《Journal of fish diseases》2015,38(1):67-74
Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality). 相似文献
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Qin-Cheng Huang Di‐Gen Qin Bei‐Ping Tan Tao Du Yuan-Zhi Yang Qi-hui Yang Shu‐Yan Chi Xiao-hui Dong 《Aquaculture Research》2020,51(2):816-827
A 5 × 3 factorial growth trial was conducted to evaluate optimal dietary protein and lipid levels (dietary protein level, DP; dietary lipid level, DL) for juvenile Sillago sihama (S. sihama) (2.0 ± 0.02 g, initial weight). Fish were fed 15 diets containing 5 DPs (350, 400, 450, 500 and 550 g/kg) and 3 DLs (60, 90 and 120 g/kg) for 8 weeks. The interaction between proteins and lipids significantly influenced the feed conversion ratio, condition factor, body composition, antioxidant indices and lipase activity (p < .05). DP 450 g/kg showed the highest average final body weight. DPs 500 and 550 g/kg significantly decreased the protein efficiency ratio (p < .05). DL 120 g/kg showed the highest percentage weight gain. The low feed conversion ratio was found in diets P45L12, P55L9 and P55L12. Diet P45L12 showed high superoxide dismutase activities. DP 450 g/kg showed the lowest average malondialdehyde content. Lipase activity was increased by increasing DP (p < .05) with a fall at DP 550 g/kg. Under the present experimental conditions, the optimal DP for S. sihama was 450 g/kg under the DL 120 g/kg. 相似文献
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William King V David L. Berlinsky Craig V. Sullivan 《Fish physiology and biochemistry》1995,14(6):489-500
Plasma estradiol-17 (E2), testosterone (T), 17,20-dihydroxy-4-pregnen-3-one (DHP) and 17,20,21-tri-hydroxy-4-pregnen-3-one (20-S) levels were measured by radioimmunoassay (RIA) in white perch (Morone americana) and white bass (M. chrysops) that were induced to undergo final oocyte maturation (FOM) with human chorionic gonadotropin (hCG). Plasma DHP levels increased in females of both species in association with oocyte germinal vesicle migration (GVM) and germinal vesicle breakdown (GVBD) and decreased thereafter. Plasma 20-S levels also increased with oocyte GVM in white bass, but were several-fold lower than DHP levels. Circulating E2 and T levels were greatest during GVM and GVBD in both species and decreased to low levels during oocyte hydration and ovulation. Follicles from white perch and white bass which received a priming injection of hCG in vivo, produced both DHP and 20-S in vitro after exposure to hCG and their oocytes underwent GVBD. Ovarian incubates from unprimed fish of either species produced only E2 and T and their oocytes did not complete GVBD. Oocytes from unprimed bass, but not perch, matured when follicles were exposed to hCG in vitro. Both trilostane and cycloheximide blocked in vitro production of DHP and 20-S and oocyte GVBD by white perch follices. DHP and 20-S were equipotent inducers of FOM in the GVBD bioassay. None of several other structurally-related steroids tested were effective within a physiological range of concentrations. These results indicate a role for DHP and 20-S in the control of FOM in white perch and white bass. 相似文献