For revealing the effects of increasing of zinc oxide nanoparticles(ZnO NPs)on denitrification and denitrifying bacteria communities in estuarine sediments,the surface sediments of two typical estuaries(the Yangtze Ri...For revealing the effects of increasing of zinc oxide nanoparticles(ZnO NPs)on denitrification and denitrifying bacteria communities in estuarine sediments,the surface sediments of two typical estuaries(the Yangtze River Estuary and the Yellow River Estuary)were added with medium concentration(170mgL−1)and high concentration(1700mgL−1)of ZnO NPs for anaerobic cul-ture in laboratory.The concentration of NO_(3)^(−)and NO_(2)^(−),the reductase activity and denitrification rate were measured by physico-chemical analysis,nirS gene abundance and denitrifying bacteria communities by molecular biological methods.The results showed that ZnO NPs inhibited NO_(3)^(−), NO_(2)^(−)reduction process and NO_(3)^(−), NO_(2)^(−)reductase activity,and a stronger inhibition effect resulting from the higher ZnO NPs concentration.ZnO NPs decreased nirS gene abundance and community diversity of denitrifying bacteria.In addition,the inhibition degree of ZnO NPs on the denitrification process of sediments in different estuaries was different.These results were of great significance for evaluating the potential ecological toxicity and risks of nanomaterials in estuaries.展开更多
Microbe communities in rhizosphere ecosystems are important for plant health but there is limited knowledge of them in the rhizospheres of genetically modified(GM) plants, especial for tree species. We used the ampl...Microbe communities in rhizosphere ecosystems are important for plant health but there is limited knowledge of them in the rhizospheres of genetically modified(GM) plants, especial for tree species. We used the amplitude sequencing method to analyze the V4 regions of the 16 S r RNA gene to identify changes in bacterial diversity and community structure in two GM lines(D520 and D521), one non-genetically modified(nonGM) line and in uncultivated soil. After chimera filtering,468.133 sequences in the domain Bacteria remained. There were ten dominant taxonomic groups(with [1 % of all sequences) across the samples. 241 of 551 genera(representing a ratio of 97.33 %) were common to all samples.A Venn diagram showed that 1.926 operational taxonomic units(OTUs) were shared by all samples. We found a specific change, a reduction in Chloroflexi, in the microorganisms in the rhizosphere soil planted with poplars. Taken together, the results showed few statistical differences in the bacterial diversity and community structure between the GM line and non-GM line, this suggests that there was no or very limited impact of this genetic modification on the bacterial communities in the rhizosphere.展开更多
The dust storms from the continent usually affect the abundance and diversity of planktons by supplying trace elements. As such, the response of heterotrophic planktonic bacteria to dusts, nutrients(i.e., nitrogen and...The dust storms from the continent usually affect the abundance and diversity of planktons by supplying trace elements. As such, the response of heterotrophic planktonic bacteria to dusts, nutrients(i.e., nitrogen and phosphorus) or ferrous dosages was investigated in the Kuroshio Extension region of the Northwest Pacific Ocean(NWPO) through on-board incubation experiments during an oceanographic survey in spring 2014. The flow cytometry and 16S rRNA high-throughput sequencing methods were applied to explore the abundance and community structure of bacteria, and the percentage of high nucleic acid bacteria(HNA%). The results showed that the heterotrophic bacteria abundance was low(average 2.55×10^5 cells mL^-1) and subjected to both nitrogen(N) and ferrous(Fe) limitation. Sand-dust deposition observably promoted the activity of heterotrophic planktonic bacteria. The maximum abundance of heterotrophic bacteria was 6.98×10^5 cells mL^-1 in the dust-dosage group, which was 44% higher than the control(P < 0.05). The HNA% in the dust-dosage group was 1.37 times higher than the control(P < 0.05). The activation mechanism was mainly related to the dissolution of N and Fe in the dusts. The relative abundance of genus Winogradskyella was significantly increased by dust deposition while the relative abundance of the genera Tenacibaculum and Hyphomonas was decreased. These variations of bacterial community structure were ascribed to the dissolution of nutrients N and P. Comparing the results of different experimental groups, this study concluded that dust storm improved the abundance of heterotrophic bacteria by dissolution of N and Fe.展开更多
Microorganisms play a key role in aquatic ecosystems.Recent studies show that keystone taxa in microbial community could change the community structure and function.However,most previous studies focus on abundant taxa...Microorganisms play a key role in aquatic ecosystems.Recent studies show that keystone taxa in microbial community could change the community structure and function.However,most previous studies focus on abundant taxa but neglected low abundant ones.To clarify the seasonal variation of bacterial and microalgal communities and understand their synergistic adaptation to diff erent environmental factors,we studied the bacterial and eukaryotic phytoplankton communities in Fenhe River that runs through Taiyuan City,central China,and their seasonal co-occurrence patterns using 16S and 18S rDNA sequencing.Results indicate that positive interaction of eukaryotic phytoplankton network was more active than negative one except winter,indicating that the cooperation(symbiotic phenomenon in which phytoplankton are interdependent and mutually benefi cial)among them could improve the adaption of microbial community to the local environmental changes and maintain the stability of microbial network.The main genera that identifi ed as keystone taxa in bacterial network were Salinivibrio and Sphingopyxis of Proteobacteria and they could respond to the variation of nitrite and make use of it,while those that identifi ed as keystone taxa in eukaryotic phytoplankton network were Pseudoschroederia and Nannochloris,and they were more susceptible to nitrate and phosphate.Mychonastes and Cryptomonas were closely related to water temperature.However,the loss of the co-occurrence by environmental factor changes aff ected the stability of network structure.This study provided a reference for analyzing relationship between bacteria and eukaryotic phytoplankton and revealing potential importance of keystone taxa in similar ecological domains in carbon,nitrogen,and phosphorus dynamics.展开更多
Purification capacity of a faucet mounted type water filter for home use was evaluated, particularly with regard to microbiological performance under different running conditions. Biofilms were formed inside the filte...Purification capacity of a faucet mounted type water filter for home use was evaluated, particularly with regard to microbiological performance under different running conditions. Biofilms were formed inside the filter, affecting the bacterial quality of the effluent water. Low flow rate, long stagnation period and high filter temperature were found favorable for bacterial growth inside. By commercial analytical profile index (API) kits, ten different bacterial species were identified in drinking water, four of which were probably contributed to the biofilm formation since they were also present in the biofilm. Fluorescence in situ hybridization (FISH) was used to confirm the API identification results, and direct viable count (DVC) method was employed to improve the sensitivity of FISH for the isolated Acinetobacter spp. and Pseudomonas putida as models. Relationship between the filter operating condition and the bacterial community alteration was partly revealed, which could provide the basic knowledge for the filter design and its practical use.展开更多
Methanotrophs play a vital role in the mitigation of methane emission from soils. However, the influences of cover crops incorporation on paddy soil methanotrophic community structure have not been fully understood. I...Methanotrophs play a vital role in the mitigation of methane emission from soils. However, the influences of cover crops incorporation on paddy soil methanotrophic community structure have not been fully understood. In this study, the impacts of two winter cover crops(Chinese milk vetch(Astragalus sinicus L.) and ryegrass(Lolium multiflorum Lam.), representing leguminous and non-leguminous cover crops, respectively) on community structure and abundance of methanotrophs were evaluated by using PCR-DGGE(polymerase chain reaction-denaturing gradient gel electrophoresis) and real-time PCR technology in a double-rice cropping system from South China. Four treatments were established in a completely randomized block design: 1) double-rice cropping without nitrogen fertilizer application, CK; 2) double-rice cropping with chemical nitrogen fertilizer application(200 kg ha^(–1) urea for entire double-rice season), CF; 3) Chinese milk vetch cropping followed by double-rice cultivation with Chinese milk vetch incorporation, MV; 4) ryegrass cropping followed by double-rice cultivation with ryegrass incorporation, RG. Results showed that cultivating Chinese milk vetch and ryegrass in fallow season decreased soil bulk density and increased rice yield in different extents by comparison with CK. Additionally, methanotrophic bacterial abundance and community structure changed significantly with rice growth. Methanotrophic bacterial pmo A gene copies in four treatments were higher during late-rice season(3.18×10^7 to 10.28×10^7 copies g^–1 dry soil) by comparison with early-rice season(2.1×10^7 to 9.62×10^7 copies g^–1 dry soil). Type Ⅰ methanotrophs absolutely predominated during early-rice season. However, the advantage of type Ⅰ methanotrophs kept narrowing during entire double-rice season and both types Ⅰ and Ⅱ methanotrophs dominated at later stage of late-rice.展开更多
This study characterizes the colonization and composition of bacterial flora in dwarf Asian honeybee (Apisflorea) larvae and compares bacterial diversity and distribu- tion among different sampling locations. A. flo...This study characterizes the colonization and composition of bacterial flora in dwarf Asian honeybee (Apisflorea) larvae and compares bacterial diversity and distribu- tion among different sampling locations. A. florea larvae were collected from 3 locations in Chiang Mai province, Thailand. Bacterial DNA was extracted from each larva using the phenol-chloroform method. Denaturing gradient gel electrophoresis was performed, and the dominant bands were excised from the gels, cloned, and sequenced for bacterial species identification. The result revealed similarities of bacterial community profiles in each individual colony, but differences between colonies from the same and different locations. A. florea larvae harbor bacteria belonging to 2 phyla (Firmicutes and Proteobac- teria), 5 classes (Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Bacilli, and Clostridia), 6 genera (Clostridium, Gilliamella, Melissococcus, Lactobacillus, Saccha- ribacter, and Snodgrassella), and an unknown genus from uncultured bacterial species. The classes with the highest abundance of bacteria were Alphaproteobacteria (34%), Bacilli (25%), Betaproteobacteria (11%), Gammaproteobacteria (10%), and Clostridia (8%), re- spectively. Similarly, uncultured bacterial species were identified (12%). Environmental bacterial species, such as Saccharibacterfloricola, were also found. This is the first study in which sequences closely related to Melissococcus plutonius, the causal pathogen re- sponsible for European foulbrood, have been identified in Thai A. florea larvae.展开更多
Objective To investigate the features of vaginal bacteria community in women with recurrent vulvovaginal candidiasis (R VVC) and its etiological risk in vaginal health. Methods Totally 237 reproductive-aged women wi...Objective To investigate the features of vaginal bacteria community in women with recurrent vulvovaginal candidiasis (R VVC) and its etiological risk in vaginal health. Methods Totally 237 reproductive-aged women with RVVC in an acute episode were studied. Whereas 230 healthy reproductive-aged women were enrolled as the control. The vaginal pH was evaluated, while vaginal secretions were sampled for Gram's staining and oilmicroscopy. By Nugent score system, the composition of vaginal communities was determined, and other micro-ecological features were approached. To describe other features of vaginal microbiota, the community's bacteria density, species diversity and predominant species were evaluated at 1 000 X magnification. Results The vaginal pH (4.53 ~ 0.30) and Nugent score (4.31 ___+ O. 73) in RVVC group were significantly increased compared with vaginal pH (4.11 __+ 0.30) and Nugent score (1.32 _+ 1.29) in control group (P〈O.05, respectively). The density of Lactoba- cillus in RVVC group was significantly lower than that in control group (P〈O.05), while the densities of Gardnerella vaginalis, Gram-positive cocci and other species were significantly higher respectively than those in control group (P〈O. 05). Species diversity of women with RVVC significantly exceeded that of control group (P〈O.05). More than half of vaginal communities in R VVC group lost Lactobacillus-dominating and were predominated by other bacteria such as Gardnerella vaginalis and Gram-positive cocci. The prevalence of Gardnerella vaginalis-dominating and Gram-positive cocci-domi- nating communities in RVVC group (37.55% and 19.83%) were significantly higher than those in control group (1.30% and 1.73%) (P〈0.05). Conclusion The significant changes in vaginal bacterial community were observed in RVVC women. Such variations in community might relate to vaginal biological barrier compromising and increase the risk to the recurrence of VVC. It is still controversial whether probiotics can prevent recurrences of VVC, and more randomized, doubleblind, placebo-controlled trials with a larger sample size should be carried out, so as to clarify its effects for the prophylaxis of RVVC.展开更多
Background:Previous studies have found that coastal eutrophication increases the influence of homogeneous selection on bacterial community assembly.However,whether seasonal changes affect the dominance of homogenous s...Background:Previous studies have found that coastal eutrophication increases the influence of homogeneous selection on bacterial community assembly.However,whether seasonal changes affect the dominance of homogenous selection in bacterial community assembly in eutrophic bays remains unclear.Sansha Bay is an enclosed bay with ongoing eutrophication,located in the southeast coast of China.We investigated the bacterial community composition at two depths of the enclosed bay across seasons and the seasonal variation in community assembly processes.Results:Diversity analyses revealed that the bacterial community composition among seasons differed significantly.By contrast,there was little difference in the community composition between the two depths.The temperature was the key environmental factor influencing the community composition.The null model indicated that the relative importance of homogeneous selection decreased in the following order:spring>winter>autumn>summer.Homogeneous selection did not always dominate the community assembly among seasons in the eutrophic bay.The effects of pure spatial variables on the community assembly were prominent in autumn and winter.Conclusions:Our results showed the seasonal influence of eutrophication on bacterial community diversity.The seasonal variation in composition and structure of bacterial communities eclipsed the vertical variability.Eutrophication could enhance the importance of homogeneous selection in the assembly processes,but the seasonal environmental differences interfered with the steady-state maintained by ongoing eutrophication and changed the community assembly processes.Homogeneous selection was not always important in bacterial community in the eutrophic enclosed bay.The bacterial community was the most complex in summer,because the composition differed from other seasons,and the assembly process was the most intricate.These findings have contributed to understanding bacterial community composition and assembly processes in eutrophic coastal ecosystems.展开更多
基金This work was supported by the National Key Research and Development Program of China(No.2018 YFC1407601)Startup Foundation for Introducing Talent of NUISTthe National Key R&D Program of China(No.2018YFD0900805).
文摘For revealing the effects of increasing of zinc oxide nanoparticles(ZnO NPs)on denitrification and denitrifying bacteria communities in estuarine sediments,the surface sediments of two typical estuaries(the Yangtze River Estuary and the Yellow River Estuary)were added with medium concentration(170mgL−1)and high concentration(1700mgL−1)of ZnO NPs for anaerobic cul-ture in laboratory.The concentration of NO_(3)^(−)and NO_(2)^(−),the reductase activity and denitrification rate were measured by physico-chemical analysis,nirS gene abundance and denitrifying bacteria communities by molecular biological methods.The results showed that ZnO NPs inhibited NO_(3)^(−), NO_(2)^(−)reduction process and NO_(3)^(−), NO_(2)^(−)reductase activity,and a stronger inhibition effect resulting from the higher ZnO NPs concentration.ZnO NPs decreased nirS gene abundance and community diversity of denitrifying bacteria.In addition,the inhibition degree of ZnO NPs on the denitrification process of sediments in different estuaries was different.These results were of great significance for evaluating the potential ecological toxicity and risks of nanomaterials in estuaries.
基金financially supported by the National High-Tech Research and Development Program of China,863Program(Grant No.2011AA100201)the National Forestry Public Welfare Research Project of China(Grant No.201004004)
文摘Microbe communities in rhizosphere ecosystems are important for plant health but there is limited knowledge of them in the rhizospheres of genetically modified(GM) plants, especial for tree species. We used the amplitude sequencing method to analyze the V4 regions of the 16 S r RNA gene to identify changes in bacterial diversity and community structure in two GM lines(D520 and D521), one non-genetically modified(nonGM) line and in uncultivated soil. After chimera filtering,468.133 sequences in the domain Bacteria remained. There were ten dominant taxonomic groups(with [1 % of all sequences) across the samples. 241 of 551 genera(representing a ratio of 97.33 %) were common to all samples.A Venn diagram showed that 1.926 operational taxonomic units(OTUs) were shared by all samples. We found a specific change, a reduction in Chloroflexi, in the microorganisms in the rhizosphere soil planted with poplars. Taken together, the results showed few statistical differences in the bacterial diversity and community structure between the GM line and non-GM line, this suggests that there was no or very limited impact of this genetic modification on the bacterial communities in the rhizosphere.
基金funded by the National Natural Science Foundation of China (No.41210008)the Major State Basic Research Development Program of China (973 Program No.2014CB953701)。
文摘The dust storms from the continent usually affect the abundance and diversity of planktons by supplying trace elements. As such, the response of heterotrophic planktonic bacteria to dusts, nutrients(i.e., nitrogen and phosphorus) or ferrous dosages was investigated in the Kuroshio Extension region of the Northwest Pacific Ocean(NWPO) through on-board incubation experiments during an oceanographic survey in spring 2014. The flow cytometry and 16S rRNA high-throughput sequencing methods were applied to explore the abundance and community structure of bacteria, and the percentage of high nucleic acid bacteria(HNA%). The results showed that the heterotrophic bacteria abundance was low(average 2.55×10^5 cells mL^-1) and subjected to both nitrogen(N) and ferrous(Fe) limitation. Sand-dust deposition observably promoted the activity of heterotrophic planktonic bacteria. The maximum abundance of heterotrophic bacteria was 6.98×10^5 cells mL^-1 in the dust-dosage group, which was 44% higher than the control(P < 0.05). The HNA% in the dust-dosage group was 1.37 times higher than the control(P < 0.05). The activation mechanism was mainly related to the dissolution of N and Fe in the dusts. The relative abundance of genus Winogradskyella was significantly increased by dust deposition while the relative abundance of the genera Tenacibaculum and Hyphomonas was decreased. These variations of bacterial community structure were ascribed to the dissolution of nutrients N and P. Comparing the results of different experimental groups, this study concluded that dust storm improved the abundance of heterotrophic bacteria by dissolution of N and Fe.
基金Supported by the National Natural Science Foundation of China(No.31770223)the Excellent Achievement Cultivation Project of Higher Education in Shanxi(No.2020KJ029)the Scientifi c and Technological Innovation Programs of Higher Education Institutions in Shanxi(No.2019L0778)。
文摘Microorganisms play a key role in aquatic ecosystems.Recent studies show that keystone taxa in microbial community could change the community structure and function.However,most previous studies focus on abundant taxa but neglected low abundant ones.To clarify the seasonal variation of bacterial and microalgal communities and understand their synergistic adaptation to diff erent environmental factors,we studied the bacterial and eukaryotic phytoplankton communities in Fenhe River that runs through Taiyuan City,central China,and their seasonal co-occurrence patterns using 16S and 18S rDNA sequencing.Results indicate that positive interaction of eukaryotic phytoplankton network was more active than negative one except winter,indicating that the cooperation(symbiotic phenomenon in which phytoplankton are interdependent and mutually benefi cial)among them could improve the adaption of microbial community to the local environmental changes and maintain the stability of microbial network.The main genera that identifi ed as keystone taxa in bacterial network were Salinivibrio and Sphingopyxis of Proteobacteria and they could respond to the variation of nitrite and make use of it,while those that identifi ed as keystone taxa in eukaryotic phytoplankton network were Pseudoschroederia and Nannochloris,and they were more susceptible to nitrate and phosphate.Mychonastes and Cryptomonas were closely related to water temperature.However,the loss of the co-occurrence by environmental factor changes aff ected the stability of network structure.This study provided a reference for analyzing relationship between bacteria and eukaryotic phytoplankton and revealing potential importance of keystone taxa in similar ecological domains in carbon,nitrogen,and phosphorus dynamics.
基金supported by the Proctor and Gamble Company and in part by Boshidian Fund of Ministry of Education of China(No.200800030046)
文摘Purification capacity of a faucet mounted type water filter for home use was evaluated, particularly with regard to microbiological performance under different running conditions. Biofilms were formed inside the filter, affecting the bacterial quality of the effluent water. Low flow rate, long stagnation period and high filter temperature were found favorable for bacterial growth inside. By commercial analytical profile index (API) kits, ten different bacterial species were identified in drinking water, four of which were probably contributed to the biofilm formation since they were also present in the biofilm. Fluorescence in situ hybridization (FISH) was used to confirm the API identification results, and direct viable count (DVC) method was employed to improve the sensitivity of FISH for the isolated Acinetobacter spp. and Pseudomonas putida as models. Relationship between the filter operating condition and the bacterial community alteration was partly revealed, which could provide the basic knowledge for the filter design and its practical use.
基金supported by the National Natural Science Foundation of China (31171509 and 30671222)the Special Fund for Agro-scientific Research in the Public Interest, China (201103001)the National Key Technology R&D Program for the 12th Five-Year Plan period (2011BAD16B15)
文摘Methanotrophs play a vital role in the mitigation of methane emission from soils. However, the influences of cover crops incorporation on paddy soil methanotrophic community structure have not been fully understood. In this study, the impacts of two winter cover crops(Chinese milk vetch(Astragalus sinicus L.) and ryegrass(Lolium multiflorum Lam.), representing leguminous and non-leguminous cover crops, respectively) on community structure and abundance of methanotrophs were evaluated by using PCR-DGGE(polymerase chain reaction-denaturing gradient gel electrophoresis) and real-time PCR technology in a double-rice cropping system from South China. Four treatments were established in a completely randomized block design: 1) double-rice cropping without nitrogen fertilizer application, CK; 2) double-rice cropping with chemical nitrogen fertilizer application(200 kg ha^(–1) urea for entire double-rice season), CF; 3) Chinese milk vetch cropping followed by double-rice cultivation with Chinese milk vetch incorporation, MV; 4) ryegrass cropping followed by double-rice cultivation with ryegrass incorporation, RG. Results showed that cultivating Chinese milk vetch and ryegrass in fallow season decreased soil bulk density and increased rice yield in different extents by comparison with CK. Additionally, methanotrophic bacterial abundance and community structure changed significantly with rice growth. Methanotrophic bacterial pmo A gene copies in four treatments were higher during late-rice season(3.18×10^7 to 10.28×10^7 copies g^–1 dry soil) by comparison with early-rice season(2.1×10^7 to 9.62×10^7 copies g^–1 dry soil). Type Ⅰ methanotrophs absolutely predominated during early-rice season. However, the advantage of type Ⅰ methanotrophs kept narrowing during entire double-rice season and both types Ⅰ and Ⅱ methanotrophs dominated at later stage of late-rice.
文摘This study characterizes the colonization and composition of bacterial flora in dwarf Asian honeybee (Apisflorea) larvae and compares bacterial diversity and distribu- tion among different sampling locations. A. florea larvae were collected from 3 locations in Chiang Mai province, Thailand. Bacterial DNA was extracted from each larva using the phenol-chloroform method. Denaturing gradient gel electrophoresis was performed, and the dominant bands were excised from the gels, cloned, and sequenced for bacterial species identification. The result revealed similarities of bacterial community profiles in each individual colony, but differences between colonies from the same and different locations. A. florea larvae harbor bacteria belonging to 2 phyla (Firmicutes and Proteobac- teria), 5 classes (Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Bacilli, and Clostridia), 6 genera (Clostridium, Gilliamella, Melissococcus, Lactobacillus, Saccha- ribacter, and Snodgrassella), and an unknown genus from uncultured bacterial species. The classes with the highest abundance of bacteria were Alphaproteobacteria (34%), Bacilli (25%), Betaproteobacteria (11%), Gammaproteobacteria (10%), and Clostridia (8%), re- spectively. Similarly, uncultured bacterial species were identified (12%). Environmental bacterial species, such as Saccharibacterfloricola, were also found. This is the first study in which sequences closely related to Melissococcus plutonius, the causal pathogen re- sponsible for European foulbrood, have been identified in Thai A. florea larvae.
文摘Objective To investigate the features of vaginal bacteria community in women with recurrent vulvovaginal candidiasis (R VVC) and its etiological risk in vaginal health. Methods Totally 237 reproductive-aged women with RVVC in an acute episode were studied. Whereas 230 healthy reproductive-aged women were enrolled as the control. The vaginal pH was evaluated, while vaginal secretions were sampled for Gram's staining and oilmicroscopy. By Nugent score system, the composition of vaginal communities was determined, and other micro-ecological features were approached. To describe other features of vaginal microbiota, the community's bacteria density, species diversity and predominant species were evaluated at 1 000 X magnification. Results The vaginal pH (4.53 ~ 0.30) and Nugent score (4.31 ___+ O. 73) in RVVC group were significantly increased compared with vaginal pH (4.11 __+ 0.30) and Nugent score (1.32 _+ 1.29) in control group (P〈O.05, respectively). The density of Lactoba- cillus in RVVC group was significantly lower than that in control group (P〈O.05), while the densities of Gardnerella vaginalis, Gram-positive cocci and other species were significantly higher respectively than those in control group (P〈O. 05). Species diversity of women with RVVC significantly exceeded that of control group (P〈O.05). More than half of vaginal communities in R VVC group lost Lactobacillus-dominating and were predominated by other bacteria such as Gardnerella vaginalis and Gram-positive cocci. The prevalence of Gardnerella vaginalis-dominating and Gram-positive cocci-domi- nating communities in RVVC group (37.55% and 19.83%) were significantly higher than those in control group (1.30% and 1.73%) (P〈0.05). Conclusion The significant changes in vaginal bacterial community were observed in RVVC women. Such variations in community might relate to vaginal biological barrier compromising and increase the risk to the recurrence of VVC. It is still controversial whether probiotics can prevent recurrences of VVC, and more randomized, doubleblind, placebo-controlled trials with a larger sample size should be carried out, so as to clarify its effects for the prophylaxis of RVVC.
基金funded by the National Natural Science Foundation of China(42176147)the Natural Science Foundation of Fujian Province of China(2021J01025)the National Key Research and Development Program of China(2018YFC1406306).
文摘Background:Previous studies have found that coastal eutrophication increases the influence of homogeneous selection on bacterial community assembly.However,whether seasonal changes affect the dominance of homogenous selection in bacterial community assembly in eutrophic bays remains unclear.Sansha Bay is an enclosed bay with ongoing eutrophication,located in the southeast coast of China.We investigated the bacterial community composition at two depths of the enclosed bay across seasons and the seasonal variation in community assembly processes.Results:Diversity analyses revealed that the bacterial community composition among seasons differed significantly.By contrast,there was little difference in the community composition between the two depths.The temperature was the key environmental factor influencing the community composition.The null model indicated that the relative importance of homogeneous selection decreased in the following order:spring>winter>autumn>summer.Homogeneous selection did not always dominate the community assembly among seasons in the eutrophic bay.The effects of pure spatial variables on the community assembly were prominent in autumn and winter.Conclusions:Our results showed the seasonal influence of eutrophication on bacterial community diversity.The seasonal variation in composition and structure of bacterial communities eclipsed the vertical variability.Eutrophication could enhance the importance of homogeneous selection in the assembly processes,but the seasonal environmental differences interfered with the steady-state maintained by ongoing eutrophication and changed the community assembly processes.Homogeneous selection was not always important in bacterial community in the eutrophic enclosed bay.The bacterial community was the most complex in summer,because the composition differed from other seasons,and the assembly process was the most intricate.These findings have contributed to understanding bacterial community composition and assembly processes in eutrophic coastal ecosystems.