长薄鳅外周血细胞的显微结构和细胞化学特征研究

长薄鳅外周血细胞可分为红细胞、中性粒细胞、单核细胞、淋巴细胞和血栓细胞.在数量上,中性粒细胞、单核细胞、淋巴细胞和血栓细胞占白细胞总数的百分比分别是17.06%、5.83%、28.16%和48.94%.细胞化学染色显示所有白细胞均含有糖原物质,所有红细胞均不含酸性磷酸酶,中性粒细胞、单核细胞、淋巴细胞和血栓细胞均含有酸性磷酸酶.非特异件酯酶染色显示单核细胞呈阳性反应,中性粒细胞、淋巴细胞和血栓细胞均为部分呈阳性反应.所有细胞的碱性磷酸酶、过氧化物酶、苏丹黑显色反应均呈阴性.     

Zoogeography and biodiversity of the freshwater fishes of Southeast Asia

The ichthyofauna of the freshwater system of Southeast Asia is extremely diverse. A recent estimate of about 1000 species is probably an understatement. More than 10 new species are being added to the list annually. The distribution pattern of the Southeast Asian freshwater fishes can be divided into five zoogeographic regions. The first one is the Salween basin in Burma, with fishes mainly of the Indian subcontinent origin such as Amblypharyngodon atkinsoni, Bangana almorae and Brachydanio jayarami. The second zoogeographic area is the Mekong, Chao Phraya and Mae Khlong drainages which harbour fishes typical of the mainland of Southeast Asia such as Acanthorhodeus deignani, Barbichthys nitidus and Cirrhinus siamensis. The Malay Peninsula is the third region whose species composition is heavily influenced by the Siamese (such as Homaloptera smithi, Tuberoschistura baenzigeri and Botia beauforti) and Indonesian (such as Botia hymenophysa, Luciocephalus pulcher and Parosphromenus deissneri) elements. The islands of Sumatra, Borneo and Java are the fourth zoogeographic area of fish distribution. These islands show a high degree of endemism, especially in fishes of the family Belontiidae. Finally, the freshwater system of the Philippines is the last zoogeographic region of Southeast Asia. The area is characterized by the presence of closely related species of the cyprinids especially in Lake Lanao. Currently, high diversity of these freshwater fishes is being threatened by land development, such as deforestation, road construction and land expansion for plantation. Recent studies in the Gombak River basin show the extermination of 41 per cent of native fish species from 1969 to 1990. This is probably due to the construction of highways, logging, as well as land clearing for agriculture.     

Differences between blood cells of juvenile and adult specimens of the pond snail Lymnaea stagnalis

Summary Blood cells (amoebocytes) of juvenile and adult specimens of the pond snail Lymnaea stagnalis were compared. Juvenile snails contain fewer circulating amoebocytes per l haemolymph. However, a higher percentage of these cells shows mitotic activity, as determined by incorporation of ³H-thymidine in vitro. Relatively more amoebocytes of juvenile snails have the characteristics of less differentiated cells: they are small and round with few inclusions, a high nucleus-to-cytoplasm ratio, and a high pyronin stainability. Enzyme cytochemical studies showed that acid phosphatase (AcP), non-specific esterase (NSE), and alkaline phosphatase (AlP) are present in all amoebocytes of juvenile and adult snails. AcP activity is relatively weak. NSE activity is dispersed throughout the cytoplasm and occasionally found in granules, whereas AlP is clearly localized in granules. Differences between the two age groups were found only for the enzyme peroxidase (PO). In juvenile snails a lower percentage of the cells is positive and the granules that contain the activity are less abundant than in amoebocytes of adults. It is suggested that, due to the above-mentioned characteristics of the amoebocytes, the activity of the internal defence system in juvenile L. stagnalis is on a lower level than that in adult snails. This might be an explanation for the fact that juvenile L. stagnalis are highly susceptible to infection by the schistosome Trichobilharzia ocellata, whereas adult snails are less susceptible.     

The Distribution and Origins of Freshwater Fishes in the Balkan Peninsula,Especially in Greece

Zoogeography of freshwater fish fauna of the Balkan peninsula south of the Danube has been studied. Four main divisions - Ponto-Aegean, Attiko-Beotia, Dalmatia and South Adriatic-Ionian - were recognized. All endemics belong to European, Euro-Siberian or Palaearctic taxa, originated from ancestors of the Euro-Siberian stock and reached the area as well as Asia Minor in Oligocene or Miocene. Central European and Danubian species are intruders of late Pliocene to Pleistocene arriving by the freshened Black Sea and its drainage basin or directly from the North (Middle Danube) by river captures.     

Response to De Silva et al. (2007): Endemic freshwater finfish of Asia: distribution and conservation status

De Silva et al . (2007) present an overview of the distribution and conservation status of the endemic freshwater fish of Asia. Within that review they use data from the IUCN Red List of Threatened Species™ (2006) to conduct an analysis of the conservation status of those endemic fish species. Their analysis is incorrect and provides a very misleading impression of the level of threat to Asian freshwater fish and to freshwater fish at the global scale. The errors stem from a misinterpretation of the data presented on the IUCN Red List. The sources of errors are discussed below and the opportunity is taken to clarify what the information on the IUCN Red List represents.     

Threatened fishes in Australia–an overview

Considering the size of the continent, the Australian freshwater fish fauna is a relatively depauperate one, comprising only about 192 species (belonging to 34 families) which spend significant portions of their life cycles in freshwater habitats. Of these freshwater species, the latest (1989) analysis indicates that six can be classified as endangered, five as vulnerable, four as potentially threatened, two as indeterminate, 32 as restricted, and 16+ as of unknown status, totalling 65 + species. Thus approximately 34% of the entire Australian freshwater fish fauna falls within the above six conservation status categories, which were established by the Australian Society for Fish Biology in 1985. Conservation problems of these fishes, and particularly man-made changes to their habitats, are discussed, and some possible management solutions outlined. Brief mention is also made of several marine species which may also fall into one or more of the above conservation categories, although not enough information is yet available to classify them accurately.     

淡水鱼类微囊藻毒素去毒酶基因的克隆

微囊藻毒素去毒酶在鱼类微囊藻毒素去毒过程中起着关键作用,研究成功克隆鲢鱼、鳙鱼、草鱼、鲫鱼、鳜鱼、罗非鱼等淡水鱼类微囊藻毒素去毒酶基因cDNA核心片段而首次获得这些淡水鱼类微囊藻毒素去毒酶氨基酸序列。鲢鱼、鳙鱼、草鱼、鲫鱼、鳜鱼、罗非鱼微囊藻毒素去毒酶基因与人、小鼠、大鼠、牛、猪、羊的谷胱甘肽S-转移酶基因氨基酸同源性为60%左右,表明淡水鱼类微囊藻毒素去毒酶基因在进化上变异性较大,与其承担微囊藻毒素去毒代谢之特殊功能相适应。     

Maintaining Biodiversity in Freshwater Ecosystems on Oceanic Islands of the Tropical Pacific

Duringthepastfiveyears,aresearchgroupfromtheHawai'iDivisionofAquaticRe-sourcesandtheLouisianaStaeUniversityMuseumofNaturalSciencehascollaboratedonaseriesofstudiesconcerningthebiologyandconservaionofstreamanimalsintheHawaiianIs-lands.Fromtheviewpointsofbothgeologyandbiology,theseislandsrepresentthenorth-ernmostextensonofPolynesia.StreamanimalsinHawai'ihaverelativesattheleveloffami-ly,genus,andoccasionallyevenspeciesnotonlyinPolynesiabutthroughoutMelanesiaandMicronesiaaswell.Forthisreason…