共查询到20条相似文献,搜索用时 15 毫秒
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本实验采用辣根过氧化物酶(HRP)逆行追踪技术对鲫鱼尾部神经分泌系统进行了研究,结果表明,尾部神经分泌细胞可分为大(60-70μm)、中(40-50μm)、小(20-30μm)三种类型,在尾部脊髓的背侧面和腹侧面都有分布,HRP的引入采用Griffin(1979)提出的缓释胶法,结果证明这种方法在鱼类神经解剖的束路示踪方而是可行的。 相似文献
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ROGER S. MILES 《Lethaia: An International Journal of Palaeontology and Stratigraphy》1970,3(4):343-362
The vertebral column and caudal fin are described from species of Acanthodes. Less-specialized acanthodians are briefly noted and shown to resemble Acanthodes spp. closely in these structures. The anterior extent of the notochord and the nature of acanthodian fin-rays are also considered. The phylogenetic significance of all these structures is discussed, and acanthodians are found to resemble the early members of other groups of gnathostome fishes mainly in primitive characters. 相似文献
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长江水系鱼体氟元素背景值特征研究 总被引:2,自引:0,他引:2
本文通过测定鱼骨氟研究了氟在鱼体中的存在特征以及氟元素背景值的地域分异特征。鱼骨氟用离子选择电极法测定。样品采集涉及长江水系186个江段、12个环境单元,12种鱼1600余尾,分析样品1154个,同时分析了黄河源鄂陵湖,以及青海湖等地区几种鱼骨氟作为参考。给出了38个环境统计单元的背景值。鱼骨氟数据以服从对数正态为主。比较了同一水环境不同鱼种鱼骨氟的差异,部分鱼种鱼骨氟差异显著,而部分鱼种两两间无显著性差异。用方差分析和多重范围分析方法分析了芜湖以上长江水系鱼体氟元素背景值,结果表明,不同环境单元同一鱼种鱼骨氟差异显著。从环境和生物因素讨论了以上统计分析结果。 相似文献
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Controversy has existed about the power stroke of cetacean locomotion. We therefore measured cross-sectional areas of the appropriate muscles of the tail and computed possible forces and bending moments. The muscle areas are approximately equal in size and a similar relationship holds for the caudal tendons. It appears that the hypoaxial and epiaxial muscles are capable of generating forces that are approximately equal. Thrust delivered in the upstroke and downstroke may therefore be equal. 相似文献
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THE CHROMOSOMES OF SALMONID FISHES 总被引:6,自引:0,他引:6
S. E. HARTLEY 《Biological reviews of the Cambridge Philosophical Society》1987,62(3):197-214
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东亚似鮈类鱼类的起源和演化 总被引:1,自引:0,他引:1
本文采用分支扩散法和分支离散法两种生物地理学方法分析了似 类的起源和演化。结果说明似类于第三纪末起源于中国北方的原始类,逐步向南扩散。在其物种分化过程中可能存在南北两个分化中心。 相似文献
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用离体血管收缩功能实验法分析了大鼠基底动脉(BA)和尾动脉(CA)平滑肌细胞G蛋白的异质性。结果显示,当BA和CA平滑肌被精氨酸血管加压素(AVP)激动后,该两种血管对G蛋白非选择性激活剂GTPγS的收缩反应发生了相反的变化:BA对GTPγS的收缩增强,并且这种收缩增强不受百日咳毒素(PT,Gi和Go抑制剂)的影响。而霍乱毒素(CT,Gs激活剂)则完全抑制这种收缩,呈单相反应。与BA相反,CA对GTPγS的收缩减弱,后者可被PT预温育反转为收缩增强,而且CT对这种收缩的抑制作用短暂,呈双相反应。结果提示,BA和CA平滑肌细胞介导激动剂收缩反应的G蚕白存在异质性。 相似文献
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逗亚科棒花鱼属鱼类的分类与系统发育关系尚未解决。研究选择线粒体Cyt b基因和核基因RAG1、MLH3及MSH6作为分子标记, 重建了棒花鱼属鱼类的系统发育关系, 并结合形态证据对该属鱼类进行了分类厘定。结果表明: 棒花鱼与钝吻棒花鱼是单系种。拉林棒花鱼与辽宁棒花鱼是并系种, 一起形成单系群。拉林棒花鱼+辽宁棒花鱼一起嵌套在小鳔逗属鱼类内部, 钝吻棒花鱼嵌套在片唇逗属鱼类内部。拉林棒花鱼+辽宁棒花鱼+钝吻棒花鱼+片唇逗属+胡逗属+小鳔逗属+琵琶逗属鱼类组成单系群, 它们一起与棒花鱼形成姊妹群关系。可量性状与可数性状均不能区分拉林棒花鱼和辽宁棒花鱼。结合系统发育关系与形态证据, 棒花鱼属鱼类的分类厘定如下: 棒花鱼属鱼类包括棒花鱼和平江棒花鱼(未取样); 辽宁棒花鱼是拉林棒花鱼的同物异名, 后者的分类位置有待进一步校订; 钝吻棒花鱼校订为钝吻片唇逗。 相似文献
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George Wald 《The Journal of general physiology》1941,25(2):235-245
1. The retinas of all marine fishes so far examined except the Labridae, and of all terrestrial vertebrates contain the rhodopsin system alone; those of fresh water fishes the porphyropsin system alone. In the present paper the visual systems of a number of euryhaline fishes are examined—fishes capable of existence in a wide range of salinities, though usually restricted in spawning either to the sea (catadromous) or to fresh water (anadromous). 2. The retinas of the anadromous salmonids (brook trout, rainbow trout, and chinook salmon) contain mixtures of the rhodopsin and porphyropsin systems, predominantly the latter. The retinas of the catadromous eel and the killifish also contain mixtures of both systems, but in reverse proportions. The retinas of the anadromous white perch and alewife contain the porphyropsin system alone. 3. There is therefore an extensive parallelism between the salinity relations of these animals and the composition of their visual systems. All of them possess predominantly or exclusively the visual system commonly associated with the environment in which the fish spawns. 4. These patterns are fixed genetically, and are to a first approximation independent of the history of the individual. They may represent transitional stages in the evolutionary migration of fishes to and from the sea. The presence of both types of visual system in the retinas of some euryhaline fishes incidentally satisfies one formal requirement of two-component color vision. 相似文献
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ELECTRON MICROSCOPIC LOCALIZATION OF ACID PHOSPHATASE AND THIAMINE PYROPHOSPHATASE ACTIVITY IN HYPOTHALAMIC NEUROSECRETORY CELLS OF THE RAT 总被引:3,自引:7,他引:3
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Joseph Osinchak 《The Journal of cell biology》1964,21(1):35-47
Supraoptic nuclei in the hypothalamus of rats were fixed for the electron microscope by vascular perfusion with solutions of glutaraldehyde followed by post fixation with osmium tetroxide. Cytochemical methods for detection of acid phosphatase and thiamine pyrophosphatase activity have been applied to glutaraldehyde-fixed frozen sections containing the neurosecretory cells. The enzyme activities have been localized to certain Golgi cisternae. Acid phosphatase activity is present in the large (0.4 µ to 1.0 µ) granules or dense bodies which are surrounded by a single limiting membrane; both features characterize these structures as lysosomes. Smaller (0.1 µ) granules also present in the perikarya are generally unreactive towards enzyme activity and resemble in form the neurosecretory granules in the neurohypophysis. 相似文献
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Hudson Hoagland 《The Journal of general physiology》1934,18(1):89-91
Records of spontaneous discharge of nerve impulses, similar to that previously described in catfish and in trout, have been obtained from lateral-line nerves of goldfish and perch, by the use of concentric micro electrodes slipped under the nerve in situ. These impulses have been followed into the central nervous system. They enter the tuberculum acusticum and thence apparently spread diffusely through the cerebellum. Cutting the lateral-line nerve on one side silences the ipsilateral tuberculum acusticum, but only reduces the intensity of ipsilateral cerebellar activity. Cutting the remaining lateral-line nerve silences activity throughout the tuberculum acusticum and the cerebellum. The maintenance of tonic activity in the tuberculum acusticum by way of lateral-line discharge may account for the inhibitory effects of the lateral-line system on auditory responses. 相似文献
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THE SPECIFICITY AND SULFHYDRYL SENSITIVITY OF THE INOSITOL TRANSPORT SYSTEM OF THE CENTRAL NERVOUS SYSTEM 总被引:3,自引:5,他引:3
R. Spector 《Journal of neurochemistry》1976,27(1):229-236
Abstract— The transport of two cyclohexitol stereoisomers, myo-inositol (inositol) and scyllo-inositol (scyllitol), from blood into the CNS in vivo and into the choroid plexus in vitro was studied. In vitro , the uptake of [3 H]scyllitol or [3 H]inositol by choroid plexuses, isolated from rabbits and incubated in artificial CSF, was measured. Both scyllitol and inositol inhibited [3 H]scyllitol or [3 H]inositol accumulation by the choroid plexus. Inositol competitively inhibited [3 H]scyllitol accumulation and both isomers had a comparable affinity (Kt = 0.1 m m ) for the single cyclohexitol accumulation system. The other 6 stereoisomers tested had an order of magnitude less affinity for the cyclohexitol accumulation system of choroid plexus. Thiol reagents that penetrate cells inhibited inositol accumulation by choroid plexus more effectively than nonpenetrating thiol reagents. In vivo , in unanesthetized rabbits. the transport of unmetabolized [3 H]inositol from blood into CSF, choroid plexus and brain was readily saturated by increasing the plasma levels of myo-inositol but not by the stereoisomer d -chiroinositol. Similarly, the transport of unmetabolized [3 H]scyllitol into CSF, brain and choroid plexus was readily saturated by increasing the plasma levels of myo-inositol. Beside documenting the stereospecificity and thiol reagent sensitivity of the inositol transport mechanism of the choroid plexus, these results provide further evidence that the choroid plexus is a locus for cyclohexitol transport between blood and CSF. Moreover, they show that scyllitol, which, like inositol, is present at a higher concentration in brain than plasma, can be transported from blood into CSF and brain by the same system that transports inositol. 相似文献
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Anthony A. Echelle Thomas E. Dowling Craig C. Moritz Wesley M. Brown 《Evolution; international journal of organic evolution》1989,43(5):984-993
Restriction-endonuclease analysis of mitochondrial DNA (mtDNA) of the unisexual M. clarkhubbsi complex and close sexual relatives indicated that the unisexual complex arose through multiple, nonreciprocal hybridizations involving females of M. peninsulae. High-resolution analyses using restriction endonucleases that cleave at 4-bp sites revealed mtDNA sequence diversity that was low among unisexuals but high among individuals of M. peninsulae. The identification of M. peninsulae as a parent of the unisexuals conflicts with some details of previous allozyme comparisons. One possibility is that the unisexuals were derived from hybridization involving M. beryllina and a recently extinct form of M. peninsulae. In contrast to the unisexuals, contemporary hybrids of M. peninsulae and M. beryllina are formed by reciprocal matings. The origins of extant unisexual lineages from nonreciprocal hybridizations, together with their low mtDNA diversity relative to the maternal ancestor, implies strong constraints on origins of unisexuality via hybridization. Data on reproduction by contemporary F1 hybrids reveal one form of genetic/developmental constraint: M. peninsulae and M. beryllina may now have diverged beyond the point where the hybrid origin of new unisexual lineages is possible. 相似文献
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GEOFFREY FRYER 《Journal of Zoology》1965,145(2):285-303
New crustaceans parasitie on African freshwater fishes of the Nile, or former Nile, and Niger systems are described. The taxonomy of a group of closely related species of Argulus is clarified, and errors in the older literature are corrected. Additional information on distribution is presented. 相似文献
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云南路南县黑龙潭水库及灌区的鱼类 总被引:2,自引:0,他引:2
云南路南县黑龙潭水库灌区的鱼类共有48种;扣除外来种12种,实有土著鱼种36种,隶属于4目7科28属。本文描记了新种大斑云南鳅YunnanilusmacrositanusLi,sp.nov和叉尾云南鳅YunnanilusforkicaudalisLi.sp.nov,并对黑龙潭水库灌区的鱼类区系和动物地理学特征作了简要分析。 相似文献