Fish type I IFNs are classified into two groups with two (group I) or four (group II) cysteines in the mature peptide and can be further divided into four subgroups, termed IFN-a, -b, -c, and -d. Salmonids possess all four subgroups, whereas other teleost species have one or more but not all groups. In this study, we have discovered two further subgroups (IFN-e and -f) in rainbow trout Oncorhynchus mykiss and analyzed the expression of all six subgroups in rainbow trout and brown trout Salmo trutta. In rainbow trout RTG-2 and RTS-11 cells, polyinosinic-polycytidylic acid stimulation resulted in early activation of IFN-d, whereas the IFN-e subgroup containing the highest number of members showed weak induction. In contrast with the cell lines, remarkable induction of IFN-a, -b, and -c was detected in primary head kidney leukocytes after polyinosinic-polycytidylic acid treatment, whereas a moderate increase of IFNs was observed after stimulation with resiquimod. Infection of brown trout with hemorrhagic septicemia virus resulted in early induction of IFN-d, -e, and -f and a marked increase of IFN-b and IFN-c expression in kidney and spleen. IFN transcripts were found to be strongly correlated with the viral burden and with marker genes of the IFN antiviral cascade. The results demonstrate that the IFN system of salmonids is far more complex than previously realized, and in-depth research is required to fully understand its regulation and function.

Although freshwaters are considered to be substantial natural sources of atmospheric methane (CH 4 ), in situ processes of CH 4 production and consumption in freshwater ecosystems are poorly understood, especially in subtropical areas, leading to uncertainties in the estimation of global CH 4 emissions. To improve our understanding of physical and biogeochemical factors affecting CH 4 dynamics in subtropical lakes, we examined vertical and seasonal profiles of dissolved CH 4 and its carbon isotope ratio (δ 13 C) and conducted incubation experiments to assess CH 4 production and oxidation in the deep subtropical Fei-Tsui Reservoir (FTR; Taiwan). The mixing pattern of the FTR is essentially monomixis, but the intensity of winter vertical mixing changes with climatic conditions. In years with incomplete vertical mixing (does not reach the bottom) and subsequent strong thermal stratification resulting in profundal hypoxia, we observed increases in sedimentary CH 4 production and thus profundal CH 4 storage with the development of reducing conditions. In contrast, in years with strong winter vertical mixing to the bottom of the reservoir, CH 4 production was suppressed under NO 3 À -rich conditions, during which denitrifiers have the competitive advantage over methanogens. Diffusive emission from profundal CH 4 storage appeared to be negligible due to the efficiency of CH 4 oxidation during ascent through methane-oxidizing bacteria (MOB) activity. Most of the profundal CH 4 was rapidly oxidized by MOB in both oxic and anoxic layers, as characterized by its carbon isotope signature. In contrast, aerobic CH 4 production in the subsurface layer, which may be enhanced under high temperatures in summer, may account for a large portion of atmospheric CH 4 emissions from this reservoir. Our CH 4 profiling results provide valuable information for future studies predicting CH 4 emissions from subtropical lakes with the progress of global warming.

No abstract

Fungi belonging to the Cordyceps species have long been used as food and herbal medicines in Asia and are especially popular as commercially available powdered supplements. Despite this acceptance and use, little is known of the phylogenetic relationships of the genus. Presently, the neighbor-joining method based on the ITS1, 5.8S rRNA, and ITS2 regions was used to construct a phylogenetic tree of 17 Cordyceps isolates. Five major groups were evident. Cordyceps sinensis was less closely related to 15 Cordyceps species but shared a closer relationship with Cordyceps agriota. PCR-single-stranded conformational polymorphism was applied to differentiate seven Cordyceps isolates: five were different from those used to construct the phylogenetic tree, based on differences in the internal spacer 2 (ITS2). The length of ITS2, amplified by primers 5.8SR and ITS4, vary between 334 and 400 bp. This segment could be used for intraspecies classification or detection of mutations and represents potential novel means of identification of this fungal genus in herbal medicines and in quality control applications in the fermentation industry.

No abstract