Geographic variation of Chevrier's field mouse (Apodemus chevrieri) (Milne-Edwards, 1868) (Muridae : Murinae) from southwestern China based on cranial morphometric variables

Geographic variation of Chevrier's field mouse (Apodemus chevrieri) (Milne-Edwards, 1868) (Muridae: Murinae) from southwestern China based on cranial morphometric variables. Zoological Studies 47(4): 393-401. A sample of 134 specimens of Apodemus chevrieri was investigated in the present study. Individuals were divided into male and female groups, and these were respectively subjected to multivariate analysis. Results indicated that 3 geographic populations of A. chevrieri inhabit southwestern China: a Sichuan population in western Sichuan Province; a northwestern Yunnan population ranging from northwestern Yunnan Province eastward to southern Sichuan Province; and a central Yunnan population in central Yunnan Province. In addition, a coefficient of difference analysis was performed among these 3 geographic populations. The results suggested that these 3 geographical populations of A. chevrieri belonged to 2 subspecies. Furthermore, we discuss the relationships of the subspecific differentiation of A. chevneri with changes in latitude in southwestern China.

Geographic variation of the Perny's Long-nosed squirrels (Dremomys pernyi) (Milne-Edwards, 1867) (Rodentia : Sciuridae) from southwestern China based on cranial morphometric variables

A sample of 114 specimens of Dremomys pernyi was investigated, 73 of which had intact skulls and were subjected to multivariate, coefficient of difference (C. D.), and cluster analyses. Results indicate that 4 subspecies (groups) of Dremomys pernyi inhabi

Geographic variation of the Anderson's Niviventer (Niviventer andersoni) (Thomas, 1911) (Rodentia: Muridae) of two new subspecies in China verified with cranial morphometric variables and pelage characteristics

A total of 66 specimens of Niviventer andersoni with intact skulls was investigated on pelage characteristics and cranial morphometric variables. The data were subjected to principal component analyses as well as to discriminant analyses, and measurement

Geographic and economic setting of Lake Victoria

Lake Victoria, besides being the second largest in the world after Lake Superior, is the largest tropical lake. Its waters are shared by Kenya (6% of the surface area), Uganda (43%), and Tanzania (51%). Before dramatic structural and functional changes manifested in the lake's ecosystem especially in the 1980s, fish life flourished in the lake's entire water column at all times of the year. Currently, the situation is much more different from what it was in the past. The exponential increase in the introduced Nile perch (Lates niloticus) and Nile tilapia (Oreochromis niloticus) stocks, siltation, wetland degradation and eutrophication have characterised the lake ecosystem. The two exotic species and the small native cyprinid (Rastrineobola argentea) form the basis of the commercial fishery that was once dominated by two native tilapiines (Oreochromis esculentus and Oreochromis variabilis) and five other large-bodied endemic fishes. Severe deoxygenation observed at shallow depths (Ochumba 1990; Hecky et al., 1994) indicates that a large volume of the lake is unable to sustain fish life. The Lake Victoria catchment is one of the most densely populated areas in East Africa, encompassing a population of about 30 million people. Widespread poverty resulting from high inflation rates, lack of opportunities and general unemployment have characterised the lakeside communities over much of the last two decades. The biophysical environment in which Lake Victoria exists makes the lake particularly susceptible to changes that occur as a result of human modification to the watershed or the lake itself, thus rendering benefits from the lake unsustainable.

Base Isolation of Buildings for Control of Ground-borne Vibration

These works, edited by Malcolm Crocker, positioned Wiley as a major player in the acoustics reference market.

Isolation of Y- and X-linked SCAR markers in yellow catfish and application in the production of all-male populations

P>Sex controls have been performed in some farmed fish species because of significant growth differences between females and males. In yellow catfish (Pelteobagrus fulvidraco), adult males are three times larger than female adults. In this study, six Y- and X-linked amplified fragment length polymorphism fragments were screened by sex-genotype pool bulked segregant analysis and individual screening. Interestingly, sequence analysis identified two pairs of allelic genes, Pf33 and Pf62. Furthermore, the cloned flanking sequences revealed several Y- and X-specific polymorphisms, and four Y-linked or X-linked sequence characterized amplified region (SCAR) primer pairs were designed and converted into Y- and X-linked SCAR markers. Consequently, these markers were successfully used to identify genetic sex and YY super-males, and applied to all-male population production. Thus, we developed a novel and simple technique to help commercial production of YY super-males and all-male populations in the yellow catfish.

Relationships between Testate Amoebae Assemblages (Protozoa) and Geographic Factors in Yunnan Plateau Lakes, China

Knowledge of the effect of geographic factors on the assemblages of protozoan testate amoebae is still limited, despite there having been a number of studies on this fauna. We applied statistical analyses to data on the distribution of testate amoebae from nine major lakes in the Yunnan Plateau, southwest China. Cluster analysis, based on community structure, separated the lakes into two groups - the oligotrophic/mesotrophic lakes and the hypercutrophic lakes - confirming the idea that the testate amoebae assemblages in lakes are closely related to the trophic status. Additionally, within the oligotrophic/mesotrophic lakes, there was distinct geographic clustering. Linear regression analysis and the Mantel test both revealed that similarity of species composition decreased with increasing geographic distance among the oligotrophic/mesotrophic lakes.

Isolation and characterization of Streptococcus dysgalactiae from diseased Acipenser schrenckii

Streptococcosis became an increasingly significant health problem in intensive aquaculture in China. Fifteen strains of Gram-positive, chain-forming coccus were isolated from moribund Amur sturgeon, Acipenser schrenckii, fanned with high density in central China. The coccoid microorganism was identified as Streptococcus dysgalactiae by means of physiological. biochemical properties and molecular analysis; furthermore, this coccus was confirmed as pathogen of sturgeon by challenge experiments and its infection potential on the cyprinid was also evaluated. To our knowledge, this was the first report of S. dysgalactiae linked to diseased A. schrenckii. (C) 2009 Elsevier B.V. All rights reserved.

Communities of gastrointestinal helminths of fish in historically connected habitats: habitat fragmentation effect in a carnivorous catfish Pelteobagrus fulvidraco from seven lakes in flood plain of the Yangtze River, China

Background: Habitat fragmentation may result in the reduction of diversity of parasite communities by affecting population size and dispersal pattern of species. In the flood plain of the Yangtze River in China, many lakes, which were once connected with the river, have become isolated since the 1950s from the river by the construction of dams and sluices, with many larger lakes subdivided into smaller ones by road embankments. These artificial barriers have inevitably obstructed the migration of fish between the river and lakes and also among lakes. In this study, the gastrointestinal helminth communities were investigated in a carnivorous fish, the yellowhead catfish Pelteobagrus fulvidraco, from two connected and five isolated lakes in the flood plain in order to detect the effect of lake fragmentation on the parasite communities. Results: A total of 11 species of helminths were recorded in the stomach and intestine of P. fulvidraco from seven lakes, including two lakes connected with the Yangtze River, i.e. Poyang and Dongting lakes, and five isolated lakes, i.e. Honghu, Liangzi, Tangxun, Niushan and Baoan lakes. Mean helminth individuals and diversity of helminth communities in Honghu and Dongting lakes was lower than in the other five lakes. The nematode Procamallanus fulvidraconis was the dominant species of communities in all the seven lakes. No significant difference in the Shannon-Wiener index was detected between connected lakes (0.48) and isolated lakes (0.50). The similarity of helminth communities between Niushan and Baoan lakes was the highest (0.6708), and the lowest was between Tangxun and Dongting lakes (0.1807). The similarity was low between Dongting and the other lakes, and the similarity decreased with the geographic distance among these lakes. The helminth community in one connected lake, Poyang Lake was clustered with isolated lakes, but the community in Dongting Lake was separated in the tree. Conclusion: The similarity in the helminth communities of this fish in the flood-plain lakes may be attributed to the historical connection of these habitats and to the completion of the life-cycles of this fish as well as the helminth species within the investigated habitats. The diversity and the digenean majority in the helminth communities can be related to the diet of this fish, and to the lacustrine and macrophytic characters of the habitats. The lake isolation from the river had little detectable effect on the helminth communities of the catfish in flood-plain lakes of the Yangtze River. The low similarities in helminth communities between the Dongting Lake and others may just be a reflection of its unique water environment and anthropogenic alterations or fragmentation in this lake.

Isolation of a novel cyanophage infectious to the filamentous cyanobacterium Planktothrix agardhii (Cyanophyceae) from Lake Donghu, China

A previously unknown cyanophage, PaV-LD (Planktothrix agardhii Virus isolated from Lake Donghu), which causes lysis of the bloom-forming filamentous cyanobacterium P. agardhii, was isolated from Lake Donghu, Wuhan, China. PaV-LD only lysed P. agardhii strains isolated from Lake Donghu and not those isolated from other lakes. The PaV-LD particle has an icosahedral, non-tailed structure, ca. 70 to 85 nm (mean +/- SD = 76 +/- 6 nm) in diameter. PaV-LD was stable at freezing temperature, but lost its infectivity at temperatures >50 degrees C. Lysis of host cells was delayed about 3 d after the PaV-LD treatment with chloroform, and the virus was inactivated by exposure to low pH (<= 4). The latent period and burst size of the PaV-LD were estimated to be 48 to 72 h and about 340 infectious units per cell, respectively. The regrowth cultures of surviving host filaments were not lysed by the PaV-LD suspension. To our knowledge, this is the first isolation and cultivation of a virus infectious to the filamentous bloom-forming cyanobacterium Planktothrix from a freshwater lake.

Isolation and characterization of Argonaute 2: A key gene of the RNA interference pathway in the rare minnow, Gobiocypris rarus

Argonaute 2 gene plays a pivotal role in RNAi in many species. Herein is the first report of the cloning and characterization of Argonaute 2 gene in fish. The full-length cDNA of Gobiocypris rarus Argonaute 2 (GrAgo2) consisted of 3073 nucleotides encoding 869 amino acid residues with a calculated molecular weight of 98.499 kDa and an estimated isoelectric point of 9.18. Analysis of the deduced amino acid sequence showed the presence of two signature domains, PAZ and Piwi. RT-PCR analysis indicated that GrAgo2 mRNA expression could be detected in widespread tissues. After infection with grass carp reovirus, GrAgo2 expression was up-regulated from 12 h post-injection (p < 0.05) and returned to control levels at 48 h post-injection (p > 0.05). These data imply that GrAgo2 is involved in antiviral defense in rare minnow. (C) 2008 Published by Elsevier Ltd.

Microsatellite marker isolation and cultured strain identification in Carassius auratus gibelio

Microsatellites have become the preferred molecular markers for strain selection and genetic breeding in fish. In this study a total of 105 microsatellites were isolated and identified in gibel carp (Carassius auratus gibelio) by microsatellite sequence searches in GenBank and other databases and by screening and sequencing of positive clones from the genomic library enriched for AG and GATA repeats. Moreover, nineteen microsatellites were randomly selected to design locus-specific primer pairs, and these were successfully used to identify and discriminate different cultured strains of gibel carp including strains A, D, L, and F. Three different types of microsatellite pattern were distinguished by the number and length of fragments amplified from the 19 primer pairs, and some microsatellite primer pairs were found to produce different microsatellite patterns among strains and strain-specific fragments. In addition, some duplicated alleles were also detected in two microsatellite patterns. Therefore, the current study provides direct molecular markers to discriminate among different cultured strains for selective breeding and aquaculture practice of gibel carp.

Isolation, characterization and genome sequence of a birnavirus strain from flounder Paralichthys olivaceus in China

A birnavirus strain, Paralichthys olivaceus birnavirus (POBV), was isolated and characterized from cultured flounder in China, and its complete genomic sequence was subsequently determined. The virus could induce cytopathic effects (CPE) in four of seven fish cell lines and was resistant to chloroform, 5-iodo-2'-deoxyuridine, acid and alkaline pH, and heat treatment. Purified virus particles had a typical icosahedral shape, with a diameter of approximately 55-60 nm. The genomic segments A and B of POBV were 3,091 and 2,780 bp in length and shared many of the features of the members of the family Birnaviridae. Segment A contained two partially overlapping ORFs encoding a polyprotein, pVP2-VP4-VP3, and a nonstructural protein, VP5, while segment B had only one ORF encoding for the VP1, a viral RNA-dependent RNA polymerase (RdRp). This is the first report about a birnavirus strain from a new non-salmonid host in China and its complete genome sequence.