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111.
112.
近年来,随着水产经济动物遗传育种研究的迅速发展.对染色体制备技术的要求越来越高。十足类甲壳动物染色体的研究开展较早,但进展却相当缓慢,自一百多年前,Carnoy首次报道了褐虾和滨蟹的染色体,迄今为止已研究过的种类仅约70多种。其主要原因在于其细胞有丝分裂中期染色体形状小,不超过4um,且数目庞大,染色体标本制备和分析都较困难,仍然仅限于染色体数目统计水平。淡水虾类染色体材料与方法的研究极为稀少, 相似文献
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114.
He-Ne激光照射罗氏沼虾腹髓鞘神经纤维的电镜观察 总被引:1,自引:0,他引:1
用He Ne激光照射罗氏沼虾 (Macrobrachiumrosenbergii)的腹髓鞘神经纤维 ,结果表明 ,神经胶质细胞为不规则形 ,核的一端较大 ,另一端分叉 ,半包裹着轴突 ,呈蝴蝶形 ,核的横轴直径为 3 0 7μm ,轴突直径为 1 5 3 μm ;在髓鞘中普遍出现增厚的膜层结构 ,且膜层结构厚薄不一 ,具有高嗜锇性、电子密度大 ,正常的膜层厚度为 3 3 3 3nm ,增厚的膜层厚度可达 1 0 0nm。在两膜层之间存在着许多颗粒状物质。 相似文献
115.
Trophic patterns of omnivorous freshwater shrimps, Exopalaemon modestus and Macrobrachium nipponensis, were investigated in two shallow eutrophic lakes by using stable isotope analysis. δ15N and δ13C of M. nipponensis and E. modestus increased with increasing body weight, which might be attributed to larger individuals ingesting organisms that feed higher
up the food chain and/or increased assimilation of benthic food items with enriched isotopic signatures. Of the freshwater
shrimps occurring in the studied lakes, those from Lake Taihu had significantly elevated δ15N and δ13C values (4.3‰ and 1.8‰, respectively) compared with those from the less eutrophic Lake Chaohu, indicating that the isotopic
signature might partially reflect the trophic states of their habitats. Mixing model results suggested that the benthic food
web provides the primary carbon source for both shrimp species, and that E. modestus assimilated relatively more pelagic food sources than M. nipponensis in these lakes.
Handling editor: S. Wellekens 相似文献
116.
近年来,随着水产经济动物遗传育种研究的迅速发展,对染色体制备技术的要求越来越高。十足类甲壳动物染色体的研究开展较早,但进展却相当缓慢,自一百多年前,Carnoy首次报道了褐虾和滨蟹的染色体,迄今为止已研究过的种类仅约70多种。其主要原因在于其细胞有丝分裂中期染色体 相似文献
117.
Zenteno R Vázquez L Martínez-Cairo S Bouquelet S Agundis C Zenteno E 《Glycoconjugate journal》2000,17(5):339-347
From the serum of juvenile freshwater prawns, we isolated by affinity chromatography on glutaraldehyde-fixed rat erythrocytes stroma, immobilized in Sephadex G-25, a sialic acid specific lectin of 9.6[emsp4 ]kDa per subunit. Comparative analysis against adult organisms purified lectin, by chromatofocusing, showed that the lectin from juvenile specimens is composed by four main isoforms with a pl of 4.2, 4.6, 5.1, and 5.6, whereas the lectin from adults is eluted at pH 4.2. The amino acid composition of the lectin obtained from adult and juvenile stages suggest identity, but the compositions are not identical since a higher content of carbohydrates was found in the lectin from younger organisms. The freshwater prawn lectin showed specificity toward N-acetylated amino sugar residues such as GlcNAc, GalNAc, Neu5Ac and Neu5,9Ac; but in juvenile organisms the lectin showed three times less hemagglutinating activity than the lectin from adults. Both lectins agglutinated rat, rabbit and chicken erythrocytes, indicating that Neu5,9Ac in specific O-glycosydically linked glycans seems to be relevant for the interaction of M. rosenbergii lectins with their specific cellular receptor. Our results suggest that the physicochemical characteristics of the lectin from the freshwater prawn are regulated through maturation. 相似文献
118.
The feeding habits and selectivity of Macrobrachium borelliiwere studied by examining the stomach content of specimens from
anox-bow lake across one year. M. borellii isomnivorous-carnivorous, feeding largely on members oflittoral-benthic communities.
The bulk of the stomach content wasformed by oligochaetes, dipteran larvae, and a variety of organismsranging from algae to
palaemonids. Copepods and cladocerans were analternative food source in winter, at low-water, when macrophytes haddeclined.
Oligochaetes and dipteran larvae were positively, algae andmicrocrustaceans negatively selected.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
119.
闽江叶形吸虫新种的生活史研究 总被引:1,自引:0,他引:1
本文报道寄生在闽江的花鲈Lateolabrax japonicus膀胱及输尿管中的闽江叶形吸虫新种Phyllo-distomum mingensis sp.nov.。本新种以其成虫的虫卵大小、睾丸卵巢形态、不具劳氏管及后蚴的焰细胞排列公式等特征不同于现有的已知种。本新种的生活史经阐明,其第一中间宿主是河蚬Corbicula fluminea,第二中间宿主是河虾Macrobrachium nipponensis与M.aspergillus。本文尚对叶形属吸虫各发育结构等问题进行讨论。 相似文献
120.
为探求罗氏沼虾精氨酸激酶(Macrobrechium rosenbergii arginine kinase,MrAK)基因特征和与病毒感染的相关性,研究通过AK基因mRNA全长克隆,并采用QPCR检测病毒感染前后不同时间点罗氏沼虾幼体AK基因的转录差异。最终克隆得到的AK序列全长为1740 bp(GenBank:KT970484),其开放阅读框包含1068个碱基,编码356个氨基酸;同源性分析显示MrAK基因编码区蛋白与多齿新米虾、南极磷虾、鲑鱼海虱和安氏伪镖水蚤的同源性分别为97%、82%、83%和79%;系统进化树分析表明,该基因与多齿新米虾的AK聚在同一分支簇,而蟹、对虾和螯虾聚在另一分支;氨基酸结构分析表明,其存在一个可能的ATP:胍基磷酸转移酶的活性位点(Cys286-Pro287-Thr288-Asn289-Leu290-Gly291-Thr292);病毒感染罗氏沼虾幼体后,其AK基因表达在第9h开始出现显著性上调,在12h时达到峰值,随后开始降低。以上研究结果表明,AK基因在无脊椎甲壳动物中存在多样性,其蛋白结构存在保守性,并且其在罗氏沼虾病毒感染过程中起到潜在的能量供给调节作用。 相似文献