East Lake(Lake Donghu),located in Wuhan,China,is a typical city freshwater lake that has been experiencing eutrophic conditions and algal blooming during recent years.Marine and fresh water are considered to contain a...East Lake(Lake Donghu),located in Wuhan,China,is a typical city freshwater lake that has been experiencing eutrophic conditions and algal blooming during recent years.Marine and fresh water are considered to contain a large number of viruses.However,little is known about their genetic diversity because of the limited techniques for culturing viruses.In this study,we conducted a viral metagenomic analysis using a high-throughput sequencing technique with samples collected from East Lake in Spring,Summer,Autumn,and Winter.The libraries from four samples each generated 234,669,71,837,12,820,and 34,236 contigs(>90 bp each),respectively.The genetic structure of the viral community revealed a high genetic diversity covering 23 viral families,with the majority of contigs homologous to DNA viruses,including members of Myoviridae,Podoviridae,Siphoviridae,Phycodnaviridae,and Microviridae,which infect bacteria or algae,and members of Circoviridae,which infect invertebrates and vertebrates.The highest viral genetic diversity occurred in samples collected in August,then December and June,and the least diversity in March.Most contigs have low-sequence identities with known viruses.PCR detection targeting the conserved sequences of genes(g20,psbA,psbD,and DNApol)of cyanophages further confirmed that there are novel cyanophages in the East Lake.Our viral metagenomic data provide the first preliminary understanding of the virome in one freshwater lake in China and would be helpful for novel virus discovery and the control of algal blooming in the future.展开更多
The concept of ecological security stems from environmental security theory, and is generally used to evaluate the ecological security of land, water resources and the city. This study applies the Pressure-Station-Res...The concept of ecological security stems from environmental security theory, and is generally used to evaluate the ecological security of land, water resources and the city. This study applies the Pressure-Station-Response （P-S-R） model and theory of ecological security with field research in 2010 to establish an index system for tourism ecological security evaluation. The findings show that tourism ecological security in Wuhan has increasingly improved from a comprehensive evaluation value of 5.8023 in 2004 to 6.459 in 2010, and has moved from a ＂sensitive＂ condition to ＂safe＂ condition. Ecological pressure and ecological response are negatively correlated, and the value of ecological response was below that of ecological pressure during the seven years. In order to make clear the impact factors affecting tourism ecological security in Wuhan, this paper summarizes ten limiting factors influencing tourism ecological security and makes several recommendations to improve tourism ecological security.展开更多
文摘East Lake(Lake Donghu),located in Wuhan,China,is a typical city freshwater lake that has been experiencing eutrophic conditions and algal blooming during recent years.Marine and fresh water are considered to contain a large number of viruses.However,little is known about their genetic diversity because of the limited techniques for culturing viruses.In this study,we conducted a viral metagenomic analysis using a high-throughput sequencing technique with samples collected from East Lake in Spring,Summer,Autumn,and Winter.The libraries from four samples each generated 234,669,71,837,12,820,and 34,236 contigs(>90 bp each),respectively.The genetic structure of the viral community revealed a high genetic diversity covering 23 viral families,with the majority of contigs homologous to DNA viruses,including members of Myoviridae,Podoviridae,Siphoviridae,Phycodnaviridae,and Microviridae,which infect bacteria or algae,and members of Circoviridae,which infect invertebrates and vertebrates.The highest viral genetic diversity occurred in samples collected in August,then December and June,and the least diversity in March.Most contigs have low-sequence identities with known viruses.PCR detection targeting the conserved sequences of genes(g20,psbA,psbD,and DNApol)of cyanophages further confirmed that there are novel cyanophages in the East Lake.Our viral metagenomic data provide the first preliminary understanding of the virome in one freshwater lake in China and would be helpful for novel virus discovery and the control of algal blooming in the future.
文摘The concept of ecological security stems from environmental security theory, and is generally used to evaluate the ecological security of land, water resources and the city. This study applies the Pressure-Station-Response （P-S-R） model and theory of ecological security with field research in 2010 to establish an index system for tourism ecological security evaluation. The findings show that tourism ecological security in Wuhan has increasingly improved from a comprehensive evaluation value of 5.8023 in 2004 to 6.459 in 2010, and has moved from a ＂sensitive＂ condition to ＂safe＂ condition. Ecological pressure and ecological response are negatively correlated, and the value of ecological response was below that of ecological pressure during the seven years. In order to make clear the impact factors affecting tourism ecological security in Wuhan, this paper summarizes ten limiting factors influencing tourism ecological security and makes several recommendations to improve tourism ecological security.
