Pepsin-soluble collagen was prepared from bullfrog skin and partially characterized. This study revealed interesting differences, such as molecular weight, amino acid composition, denaturation temperature (Td), in the...Pepsin-soluble collagen was prepared from bullfrog skin and partially characterized. This study revealed interesting differences, such as molecular weight, amino acid composition, denaturation temperature (Td), in the frog skin collagen when compared to the known vertebrate collagens. This study gives hints that bullfrog skin can be a potential, safe alternative source of collagen from cattle for use in various fields.展开更多
Invasive predators have been widely regarded as one of the principle drivers of the global decline of amphibians, which are among the most threatened vertebrate taxon on Earth. The American bullfrog （Lithobates cates...Invasive predators have been widely regarded as one of the principle drivers of the global decline of amphibians, which are among the most threatened vertebrate taxon on Earth. The American bullfrog （Lithobates catesbeianus） is identiifed as one of the most successful vertebrate invaders and has caused the decline or extinction of some native amphibians in many regions and countries including China. Based on ifeld surveys and stomach content analyses, we examined the diet composition of the invasive bullfrog for the ifrst time in two invaded populations in Yunnan Province, southwestern China, a region of global conservation priority, during the breeding season from 2008 to 2014. Additionally, we conducted the first quantitative study on the prey selection of this global invader among their invaded ranges after controlling for the local anuran assemblage and other aquatic preys in the environment. Our results showed that the range of food items in the stomachs of bullfrogs spanned more than 30 species belonging to ten taxonomic classes. Both of post-metamorphosis individuals and juveniles preyed upon native frogs, independent of the bullfrog’s body size and mouth width. Importantly, Jacobs’ selection index showed a bullfrog preference for the Yunnan pond frog （Babina pleuraden）, one native endemic anuran with population decline, in terms of both food volume and occurrence. We therefore provided direct evidence on the predation impact of the invasive bullfrog on an endemic anuran and urged further efforts to prevent the dispersal of this invader into more fragile habitats to reduce their negative impacts on native amphibians.展开更多
The tested strain from typical clinical cases,and the physio-chemical characteristics,16 S rRNA gene sequence and drug sensitivity challenge property were analyzed.This isolate was determined as Streptococcus agalacti...The tested strain from typical clinical cases,and the physio-chemical characteristics,16 S rRNA gene sequence and drug sensitivity challenge property were analyzed.This isolate was determined as Streptococcus agalactiae,16 S rRNA gene fragment of 1 280 bp in length.Blast analysis showed that this fragment shared a 100% homology with the conservative region of Streptococcus agalactiae isolate（AB023574）,Streptococcus dysqalactiae isolate（HM146084.1,AB537922,EU075033）,Streptococcus difficilis isolate（AB112407） accessed in Genbank.The isolate was sensitive to ciprofloxacin,neomycin,spectinomycin,furadantin and enoxacin.The results lay foundation for the effective control,rational medication and vaccine preparation for Streptococcus disease on bullfrogs.展开更多
Native species may decline quickly when confronted with an exotic species to which they are not adapted. The extent of decline may depend on the abundance of an invader and the length of time since it first arrived in...Native species may decline quickly when confronted with an exotic species to which they are not adapted. The extent of decline may depend on the abundance of an invader and the length of time since it first arrived in the community （residence time）, and the interaction between these two variables. We tested these effects using data on the effects of American bullfrog Lithobates catesbeianus invasion on native frog communities in 65 permanent lentic waters on islands in the Zhoushan Archipel- ago, China. We examined variation in native frog abundance and species richness in relation to features of the American bullfrog invasion, habitat disturbance, characteristics of the water body and fish communities and the presence of red swamp crayfish. Bullfrog invaded sites had lower native frog density and species richness, higher submerged vegetation cover and greater fre- quency of repairs to the water body than did non-invaded sites. The minimum adequate general linear mixed models showed that both native frog density and species richness were negatively related to post-metamorphosis bullfrog density, and that native frog species richness was also positively related to the vegetation cover. There was no effect on either native frog density or species richness of residence time or its interaction with bullfrog density, or of the abundance of bullfrog tadpoles. The results suggested that post-metamorphosis bullfrogs had impacts on native frog communities in the islands, and that the extents of these impacts are proportional to post-metamorphosis bullfrog density展开更多
牛蛙的生态养殖受到了养殖者的关注与重视。文章结合安徽省宿松县的实际情况,介绍了牛蛙(Rana catesbeiana)的生态养殖技术,包括牛蛙养殖场址的选择、养殖池的建造、养殖模式,以及常见的红腿病(Red-leg disease of frog)的防治措施,可...牛蛙的生态养殖受到了养殖者的关注与重视。文章结合安徽省宿松县的实际情况,介绍了牛蛙(Rana catesbeiana)的生态养殖技术,包括牛蛙养殖场址的选择、养殖池的建造、养殖模式,以及常见的红腿病(Red-leg disease of frog)的防治措施,可供养殖者参考。展开更多
文摘Pepsin-soluble collagen was prepared from bullfrog skin and partially characterized. This study revealed interesting differences, such as molecular weight, amino acid composition, denaturation temperature (Td), in the frog skin collagen when compared to the known vertebrate collagens. This study gives hints that bullfrog skin can be a potential, safe alternative source of collagen from cattle for use in various fields.
基金supported by grants from National Natural Science Foundation of China (31200416 and 31370545)The collection and handling of amphibians were conducted by the Animal Care and Use Committee of Institute of Zoology, Chinese Academy of Sciences (Project No. 2008/73)
文摘Invasive predators have been widely regarded as one of the principle drivers of the global decline of amphibians, which are among the most threatened vertebrate taxon on Earth. The American bullfrog （Lithobates catesbeianus） is identiifed as one of the most successful vertebrate invaders and has caused the decline or extinction of some native amphibians in many regions and countries including China. Based on ifeld surveys and stomach content analyses, we examined the diet composition of the invasive bullfrog for the ifrst time in two invaded populations in Yunnan Province, southwestern China, a region of global conservation priority, during the breeding season from 2008 to 2014. Additionally, we conducted the first quantitative study on the prey selection of this global invader among their invaded ranges after controlling for the local anuran assemblage and other aquatic preys in the environment. Our results showed that the range of food items in the stomachs of bullfrogs spanned more than 30 species belonging to ten taxonomic classes. Both of post-metamorphosis individuals and juveniles preyed upon native frogs, independent of the bullfrog’s body size and mouth width. Importantly, Jacobs’ selection index showed a bullfrog preference for the Yunnan pond frog （Babina pleuraden）, one native endemic anuran with population decline, in terms of both food volume and occurrence. We therefore provided direct evidence on the predation impact of the invasive bullfrog on an endemic anuran and urged further efforts to prevent the dispersal of this invader into more fragile habitats to reduce their negative impacts on native amphibians.
基金Supported by Scientific and Technological Project of Huzhou City(2009GN03)Major Agricultural Program in Zhejiang Province(2009C12056)
文摘The tested strain from typical clinical cases,and the physio-chemical characteristics,16 S rRNA gene sequence and drug sensitivity challenge property were analyzed.This isolate was determined as Streptococcus agalactiae,16 S rRNA gene fragment of 1 280 bp in length.Blast analysis showed that this fragment shared a 100% homology with the conservative region of Streptococcus agalactiae isolate（AB023574）,Streptococcus dysqalactiae isolate（HM146084.1,AB537922,EU075033）,Streptococcus difficilis isolate（AB112407） accessed in Genbank.The isolate was sensitive to ciprofloxacin,neomycin,spectinomycin,furadantin and enoxacin.The results lay foundation for the effective control,rational medication and vaccine preparation for Streptococcus disease on bullfrogs.
基金Acknowledgements We thank Feng XU and Yanping WANG for helping a part of field works and Richard Duncan for comments on the manuscript. This work was supported by a grant from National Science foundation （No. 30870312） and by a grant from the ＂973＂ program （No. 2007CB411600）.
文摘Native species may decline quickly when confronted with an exotic species to which they are not adapted. The extent of decline may depend on the abundance of an invader and the length of time since it first arrived in the community （residence time）, and the interaction between these two variables. We tested these effects using data on the effects of American bullfrog Lithobates catesbeianus invasion on native frog communities in 65 permanent lentic waters on islands in the Zhoushan Archipel- ago, China. We examined variation in native frog abundance and species richness in relation to features of the American bullfrog invasion, habitat disturbance, characteristics of the water body and fish communities and the presence of red swamp crayfish. Bullfrog invaded sites had lower native frog density and species richness, higher submerged vegetation cover and greater fre- quency of repairs to the water body than did non-invaded sites. The minimum adequate general linear mixed models showed that both native frog density and species richness were negatively related to post-metamorphosis bullfrog density, and that native frog species richness was also positively related to the vegetation cover. There was no effect on either native frog density or species richness of residence time or its interaction with bullfrog density, or of the abundance of bullfrog tadpoles. The results suggested that post-metamorphosis bullfrogs had impacts on native frog communities in the islands, and that the extents of these impacts are proportional to post-metamorphosis bullfrog density
