To explore the relationships between community composition and the environment in a reservoir ecosystem, plankton communities from the Three Gorges Reservoir Region were studied by PCR-denaturing gradient gel electrop...To explore the relationships between community composition and the environment in a reservoir ecosystem, plankton communities from the Three Gorges Reservoir Region were studied by PCR-denaturing gradient gel electrophoresis fingerprinting. Bacterial and eukaryotic operational taxonomic units （OTUs）, generated by DGGE analysis of the PCR-amplified 16S and 18S rRNA genes, were used as surrogates for the dominant ＂biodiversity units＂. OTU composition among the sites was heterogeneous; 46.7% of the total bacterial OTUs （45） and 64.1% of the eukaryotic OTUs （39） were identified in less than half of the sampling sites. Unweighted pair group method with arithmetic averages （UPGMA） clustering of the OTUs suggested that the plankton communities in the Xiangxi Rive sites were not always significantly different from those from the Yangtze River sites, despite clear differences in their environmental characterizations. Canonical correspondence analysis （CCA） was applied to further investigate the relationships between OTU composition and the environmental factors. The first two CCA ordination axes suggested that the bacterial community composition was primarily correlated with the variables of NO3^--N, dissolved oxygen （DO）, and SiO3^2--Si, whereas, the eukaryotic community was mainly correlated with the concentrations of DO, PO4^3--P, and SiO3^2--Si.展开更多
Bioaerosol charge information is of vital importance for their electrostatic collection. Here, electrostatic means and molecular tools were applied to studying bioaerosol charge dynamics. Positively or negatively char...Bioaerosol charge information is of vital importance for their electrostatic collection. Here, electrostatic means and molecular tools were applied to studying bioaerosol charge dynamics. Positively or negatively charged bioaerosols were collected using an electrostatic sampler operated with a field strength of 1.1 kV cm 1 at a flow rate of 3 L min 1 for 40 min. Those with fewer or no charges bypassing the sampler were also collected using a filter at the downstream of the electrostatic sampler in one environment. The experiments were independently conducted three times in three different environments. The collected bacterial aerosols were cultured directly on agar plates at 26°C, and the colony forming units (CFU) were manually counted. In addition, the CFUs were washed off from the agar plates, and further subjected to polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) for culturable diversity analysis. The results revealed remarkable differences in positively and negatively charged culturable bacterial aerosol concentration and diversity among the studied environments. In the office environment, negatively charged culturable bacterial aerosols appeared to dominate (P = 0.0489), while in outdoor and hotel environments both polarities had similar concentration levels (P = 0.078, P = 0.88, respectively). DGGE patterns for positively charged culturable bacterial aerosols were shown strikingly different from those of negatively charged regardless of the sampling environments. In addition, for each of the environments positively charged culturable bacterial aerosols collected were found to have more band pattern similarity with those positively charged for respective regions of agar plates than those negatively charged, and vice versa. The information developed here is useful for developing efficient electrostatic sampling protocols for bioaerosols.展开更多
基金This work was supported by the National Natural Science Foundation of China(No.30490232,30570240)the Major State Basic Research Development Program of China(No.2002CB412308).
文摘To explore the relationships between community composition and the environment in a reservoir ecosystem, plankton communities from the Three Gorges Reservoir Region were studied by PCR-denaturing gradient gel electrophoresis fingerprinting. Bacterial and eukaryotic operational taxonomic units （OTUs）, generated by DGGE analysis of the PCR-amplified 16S and 18S rRNA genes, were used as surrogates for the dominant ＂biodiversity units＂. OTU composition among the sites was heterogeneous; 46.7% of the total bacterial OTUs （45） and 64.1% of the eukaryotic OTUs （39） were identified in less than half of the sampling sites. Unweighted pair group method with arithmetic averages （UPGMA） clustering of the OTUs suggested that the plankton communities in the Xiangxi Rive sites were not always significantly different from those from the Yangtze River sites, despite clear differences in their environmental characterizations. Canonical correspondence analysis （CCA） was applied to further investigate the relationships between OTU composition and the environmental factors. The first two CCA ordination axes suggested that the bacterial community composition was primarily correlated with the variables of NO3^--N, dissolved oxygen （DO）, and SiO3^2--Si, whereas, the eukaryotic community was mainly correlated with the concentrations of DO, PO4^3--P, and SiO3^2--Si.
基金supported by the National Natural Science Foundation of China (21277007, 21077005 and 41121004)
文摘Bioaerosol charge information is of vital importance for their electrostatic collection. Here, electrostatic means and molecular tools were applied to studying bioaerosol charge dynamics. Positively or negatively charged bioaerosols were collected using an electrostatic sampler operated with a field strength of 1.1 kV cm 1 at a flow rate of 3 L min 1 for 40 min. Those with fewer or no charges bypassing the sampler were also collected using a filter at the downstream of the electrostatic sampler in one environment. The experiments were independently conducted three times in three different environments. The collected bacterial aerosols were cultured directly on agar plates at 26°C, and the colony forming units (CFU) were manually counted. In addition, the CFUs were washed off from the agar plates, and further subjected to polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) for culturable diversity analysis. The results revealed remarkable differences in positively and negatively charged culturable bacterial aerosol concentration and diversity among the studied environments. In the office environment, negatively charged culturable bacterial aerosols appeared to dominate (P = 0.0489), while in outdoor and hotel environments both polarities had similar concentration levels (P = 0.078, P = 0.88, respectively). DGGE patterns for positively charged culturable bacterial aerosols were shown strikingly different from those of negatively charged regardless of the sampling environments. In addition, for each of the environments positively charged culturable bacterial aerosols collected were found to have more band pattern similarity with those positively charged for respective regions of agar plates than those negatively charged, and vice versa. The information developed here is useful for developing efficient electrostatic sampling protocols for bioaerosols.
