Search

Under intensive and high-density aquaculture conditions, the cultured eels are easily infected by a variety of virulent Aeromonas species, which leads to high mortality rates and economic losses. In this study, a visual closed-tube loop-mediated isothermal amplification (LAMP) assay was developed for targeting aerolysin gene of Aeromonas species affecting cultured eels. Firstly, two pairs of outer and inner primers were designed against a conserved region of the aer gene from different Aeromonas species. Secondly, the weakly buffered aer-LAMP assay was optimized under various Mg2+ concentrations, different amplification times and amplification temperatures followed by the visual evaluation of phenol red dye and SYTO-9. Thirdly, the detection limit of the aer-LAMP assay showed 16.8 copy/μl which was simultaneously evaluated by the color changes from red to yellow and the real-time fluorescence amplification curves. The specificity of the aer-LAMP assay showed no cross-reaction with other related species. In addition, 30 Aeromonas strains and 40 clinical tissues from eels were used to further validate the effectiveness of the aer-LAMP assay. All the results showed that the aer-LAMP assay provided a rapid, simple, and reliable method for detecting Aeromonas harboring the aerolysin gene, which would be helpful for the prevention and control of Aeromonas infection in cultured eels. [ABSTRACT FROM AUTHOR]

Water quality, size, connectivity and other physical properties of hydrological systems might have different functions in the formation and maintenance of biodiversity, but this remains mostly unclear due to the lack of undisturbed sites for experimental modelling. Alpine freshwater habitats such as micro-waterbodies (MWB) represent a kind of natural system suitable for biodiversity research. In order to assess potential linkages between environmental factors, connectivity of MWBs and aquatic species richness, we conducted a pilot study in two separated MWB systems located in Gaoligong Mountain, northwest Yunnan province, China. A total of 27 MWBs have been analyzed, including 22 connected and 5 isolated bodies. 13 conventional environmental factors were tested while all kinds of aquatic macro-organisms were collected and classified. Results showed a high environmental heterogeneity among MWBs and significant differences between the two systems but only a few environmental variables such as the depth of soil bottom, total Nitrogen and altitude were related to species richness and the formation of the community structure. As a benefit from the high environmental heterogeneity, the cascaded MWB systems provided divergent habitats able to support species richness at a higher level than the same number of randomly selected MWBs. This finding supports the idea that habitat connectivity matters also in extremely small aquatic ecosystems. Moreover, although still a preliminary result, a polarization effect within connected chains where edge MWBs host higher taxa and endemic taxa richness as well as larger populations, was detectable. This study gives interesting insights on the spatial processes driving community structure and a new prospective for biodiversity conservation. Since alpine MWBs have significant effects on the maintenance of watershed biodiversity, further research on such small and crucial ecosystems is encouraged. [ABSTRACT FROM AUTHOR]

From 2007, the economic turmoil in the USA has had a dramatic impact on immigrant populations living within the nation’s borders. One such group is Chinese migrants who came to the USA as students in the 1980s and 1990s. This paper focuses on a segment of this population—medical professionals—who obtained graduate degrees in the USA and subsequently stayed on to work in pharmaceutical or health industries in Philadelphia’s metropolitan area. As a result of the economic crises in the USA and also the burgeoning market in China, pharmaceutical companies have begun to repatriate some of these Chinese professionals. This paper will examine reflections on the return experience to Shanghai, which has developed rapidly to become the most commercialized modern city in China as a result of the market reform initiated in 1979. I argue that neoliberal ideology in the USA not only forces these Chinese immigrants back to China, but also challenges their concepts of identity and citizenship, including cultural citizenship. This paper also examines the ways in which processes of change are affected by global capitalism and neoliberalism. [ABSTRACT FROM AUTHOR]