Twenty water bodies in China were sampled,and 186 strains of different Microcystis species were isolated,from which eight morpho species were identified and 43 stains containing the mcyB gene were detected.Phylogeneti...Twenty water bodies in China were sampled,and 186 strains of different Microcystis species were isolated,from which eight morpho species were identified and 43 stains containing the mcyB gene were detected.Phylogenetic analysis based on the mcyB gene indicated that the microcystin(MC)-producing Microcystis in China could be divided into two groups(ⅠandⅡ)and showed significant differences between the two groups.The maximum sequence similarity was 69.1%.Microcystins(MCs)were measured by high-performance liquid chromatography(HPLC)analysis,and no microcystin-RR(MC-RR)was detected in some strains belonging to GroupⅡ.Compared to other regions of the world,the proportion of Chinese MC-producing was different,and the regional differences were more obvious.A whole-cell polymerase chain reactio(PCR)assay was conducted to analyze the proportion of the mcyB gene in the laboratory cultured and field cultured Microcystis.The proportion of four morphospecies(M.vividis,M.ichthyoblabe,M.novacekii,and M.aeruginosa)that contained the mcyB gene exceeded 50%in the field cultured sample s.Compared with former studies,M.aeruginosa was the mo st likely morphotype that can produce MCs in the world.This study provided new insight of Microcystis hazard assessment and field monitoring.展开更多
Blooms of microcystin-producing cyanobacteria are a problem worldwide. Microcystin is a liver hepatotoxin commonly found in bodies of water and is produced mainly by the genus Microcystis. The aim of the present study...Blooms of microcystin-producing cyanobacteria are a problem worldwide. Microcystin is a liver hepatotoxin commonly found in bodies of water and is produced mainly by the genus Microcystis. The aim of the present study was to develop and assess a competitive PCR method for the quantification of toxic and non-toxic Microcystis cells using the cpcBA and mcyB genes, which are respectively involved in the formation of phycocyanin and biosynthesis of microcystin. For the acquisition of competitor DNA, amplification sequences were carried out of the “cell DNA equivalent” of microcystin-producing (BCCUSP18) and non-microcystin-producing (BCCUSP03) strains of Microcystis spp. using primers described in the literature as well as others designed for the present study. The method was successfully developed, as competitor DNA was constructed and co-amplified with the target DNA. Competitive PCR proved to be useful in quantifying toxic and non-toxic cells of Microcystis spp. strains, representing a helpful methodology tool to study isolated toxin-producing cyanobacteria.展开更多
Harmful cyanobacterial blooms, especially Microcystis blooms, occur worldwide and draw widespread attention. The dynamics of microcystin-producing Microcystis and competition between microcystin-producing Microcystis ...Harmful cyanobacterial blooms, especially Microcystis blooms, occur worldwide and draw widespread attention. The dynamics of microcystin-producing Microcystis and competition between microcystin-producing Microcystis and non-microcystin-producing Microcystis are key to predicting and treating Microcystis blooms. Multiplex qPCR is a useful tool to assess such issues. In this study, we developed multiplex qPCR methods with newly-designed probes and primers for the microcystin-synthesis related genes mcyA and mcyE. We used seven toxic Microcystis strains and four non-toxic Microcystis strains to compare the differences in the ratios of toxic and non-toxic Microcystis in mixed cultures, which were calculated using abundances of the genes mcyA, mcyB, mcyD, mcy E and phycocyanin( PC). We also compared traditional cell counting and multiplex qPCR. Hierarchical clustering and principal component analysis indicated that mcyD was the most suitable mcy gene for quantification in laboratory experiments. mcyB abundances were always higher; we suggest that the amount of toxic Microcystis measured using mcyB might overestimate the actual percentages.展开更多
基金the Science and Technology Project of Henan Province(Nos.19A180018,192102310306)the Key Laboratory of Algal Biology,Institute of Hydrobiology,Chinese Academy of Sciences(No.2018001)。
文摘Twenty water bodies in China were sampled,and 186 strains of different Microcystis species were isolated,from which eight morpho species were identified and 43 stains containing the mcyB gene were detected.Phylogenetic analysis based on the mcyB gene indicated that the microcystin(MC)-producing Microcystis in China could be divided into two groups(ⅠandⅡ)and showed significant differences between the two groups.The maximum sequence similarity was 69.1%.Microcystins(MCs)were measured by high-performance liquid chromatography(HPLC)analysis,and no microcystin-RR(MC-RR)was detected in some strains belonging to GroupⅡ.Compared to other regions of the world,the proportion of Chinese MC-producing was different,and the regional differences were more obvious.A whole-cell polymerase chain reactio(PCR)assay was conducted to analyze the proportion of the mcyB gene in the laboratory cultured and field cultured Microcystis.The proportion of four morphospecies(M.vividis,M.ichthyoblabe,M.novacekii,and M.aeruginosa)that contained the mcyB gene exceeded 50%in the field cultured sample s.Compared with former studies,M.aeruginosa was the mo st likely morphotype that can produce MCs in the world.This study provided new insight of Microcystis hazard assessment and field monitoring.
基金supported by grants from“Fundacao de Amparoa Pesquisa do Estado de Sao Paulo”(Proc.2007/57672-0)CNPq(Proc.301739/2011-0)-Brazilian agencies for the promotion of Science.
文摘Blooms of microcystin-producing cyanobacteria are a problem worldwide. Microcystin is a liver hepatotoxin commonly found in bodies of water and is produced mainly by the genus Microcystis. The aim of the present study was to develop and assess a competitive PCR method for the quantification of toxic and non-toxic Microcystis cells using the cpcBA and mcyB genes, which are respectively involved in the formation of phycocyanin and biosynthesis of microcystin. For the acquisition of competitor DNA, amplification sequences were carried out of the “cell DNA equivalent” of microcystin-producing (BCCUSP18) and non-microcystin-producing (BCCUSP03) strains of Microcystis spp. using primers described in the literature as well as others designed for the present study. The method was successfully developed, as competitor DNA was constructed and co-amplified with the target DNA. Competitive PCR proved to be useful in quantifying toxic and non-toxic cells of Microcystis spp. strains, representing a helpful methodology tool to study isolated toxin-producing cyanobacteria.
基金Supported by the National Natural Science Foundation of China(Nos.31370418,41561144008)the Jiangxi Water Science and Technology Fund(No.KT201602)the State Key Laboratory of Freshwater Ecology and Biotechnology(No.2016FBZ07)
文摘Harmful cyanobacterial blooms, especially Microcystis blooms, occur worldwide and draw widespread attention. The dynamics of microcystin-producing Microcystis and competition between microcystin-producing Microcystis and non-microcystin-producing Microcystis are key to predicting and treating Microcystis blooms. Multiplex qPCR is a useful tool to assess such issues. In this study, we developed multiplex qPCR methods with newly-designed probes and primers for the microcystin-synthesis related genes mcyA and mcyE. We used seven toxic Microcystis strains and four non-toxic Microcystis strains to compare the differences in the ratios of toxic and non-toxic Microcystis in mixed cultures, which were calculated using abundances of the genes mcyA, mcyB, mcyD, mcy E and phycocyanin( PC). We also compared traditional cell counting and multiplex qPCR. Hierarchical clustering and principal component analysis indicated that mcyD was the most suitable mcy gene for quantification in laboratory experiments. mcyB abundances were always higher; we suggest that the amount of toxic Microcystis measured using mcyB might overestimate the actual percentages.
