Candidate division JS 1-and Chloroflexi-related bacteria are ubiquitous in various deep marine sediments worldwide, yet almost nothing is known about their abundance and diversity in cold seep sediments. Here, we inve...Candidate division JS 1-and Chloroflexi-related bacteria are ubiquitous in various deep marine sediments worldwide, yet almost nothing is known about their abundance and diversity in cold seep sediments. Here, we investigated the abundance and diversity of JS1- and Chloroflexi-related bacteria in a cold seep marine sediment core collected from the northern South China Sea （SCS） with the employment of quantitative polymerase chain reaction （qPCR） and 16S rRNA gene phylogenetic analyses. The qPCR results showed that 16S rRNA gene copies per gram of sediments for the total bacteria and JS 1- and Chloroflexi-related bacteria were at magnitudes of 108 and 106, respectively. The relative abundance of JS 1- and Chloroflexi-related 16S rRNA genes to that of total bacteria was 0.07%-8.78% throughout the core. Phyloge- netic analyses showed that the JS-1 related clone sequences were dominant throughout the core. Our study provided insights into abundance and diversity of JS 1- and Chloroflexi-related bacteria in the northern SCS cold seep sediments.展开更多
The soil microbiome that plays important ecological roles in mountains and forests is influenced by anthropogenic and natural causes.Human activity,particularly harvesting or thinning,affects the soil microbiome in fo...The soil microbiome that plays important ecological roles in mountains and forests is influenced by anthropogenic and natural causes.Human activity,particularly harvesting or thinning,affects the soil microbiome in forests by altering environmental conditions,such as vegetation,microclimate,and soil physicochemical properties.The purpose of this study was to investigate the effects on forest thinning on the diversity and composition of the soil bacterial community.From next-generation sequencing results of the 16S rRNA gene,we examined differences in soil bacterial diversity and community composition before and after thinning at Mt.Janggunbong,South Korea.We identified 40 phyla,103 classes,192 orders,412families,947 genera,and 3,145 species from the soil samples.Acidobacteria and Proteobacteria were the most dominant bacterial phyla in the forest soil of Mt.Janggunbong.Soil bacterial diversity measures(richness,Shannon diversity index,and evenness)at the phylum level increased after thinning,whereas species-level taxonomic richness decreased after thinning.Thinning provided new opportunities for bacterial species in Chloroflexi,Verrucomicrobia,Nitrospirae,and other nondominant bacterial taxa,especially for those not found in Mt.Janggunbong before thinning,to settle and adapt to the changing environment.Our results suggested that thinning affected the diversity and composition of soil bacterial communities in forests and mountains.展开更多
This study is focused on investigation of biofilms formed in an anaerobic laboratory-scale bioreactor fed with medium for anammox bacteria oxidizing ammonia with nitrite. The mixed culture of anammox bacteria was enri...This study is focused on investigation of biofilms formed in an anaerobic laboratory-scale bioreactor fed with medium for anammox bacteria oxidizing ammonia with nitrite. The mixed culture of anammox bacteria was enriched from the microbial community that sampled from the activated sludge of a denitrifying reactor at a wastewater treatment station located in the Sochi region, Russia. This community forms biofilms on the surface of the flexible polymer brush carriers, which are used for biomass immobilization in both laboratory and full-scale bioreactors. Anammox bacteria were discovered in the activated sludge community. The anammox community was enriched by incubation in an up-flow laboratory-scale anaerobic bioreactor with a flexible brush carrier. In the course of ~3 years, the loading rate of nitrogen substrates (ammonium and nitrite) increased from 100 to 5000 mg N L-1 day-1. The concentration of the substrates in the upper part of the reactor was 40 times less than in the influent. The pH values were 7.5 at the bottom and up to 9 in the upper part up of the reactor. Biofilms of two types developed in the reactor. Bunches of irregular spherical granules formed on the carrier filaments, while films of irregular thickness containing submerged spherical granules were formed on the walls of reactor. The anammox population was found to consist of at least three active species: a new strain of Candidatus “Jettenia asiatica” named “strain ecos” and two species of the genus Candidatus “Brocadia”. Other types of bacteria found in the community, including members of phylum Chloroflexi, were presumably involved in biofilm spatial organization.展开更多
文摘Candidate division JS 1-and Chloroflexi-related bacteria are ubiquitous in various deep marine sediments worldwide, yet almost nothing is known about their abundance and diversity in cold seep sediments. Here, we investigated the abundance and diversity of JS1- and Chloroflexi-related bacteria in a cold seep marine sediment core collected from the northern South China Sea （SCS） with the employment of quantitative polymerase chain reaction （qPCR） and 16S rRNA gene phylogenetic analyses. The qPCR results showed that 16S rRNA gene copies per gram of sediments for the total bacteria and JS 1- and Chloroflexi-related bacteria were at magnitudes of 108 and 106, respectively. The relative abundance of JS 1- and Chloroflexi-related 16S rRNA genes to that of total bacteria was 0.07%-8.78% throughout the core. Phyloge- netic analyses showed that the JS-1 related clone sequences were dominant throughout the core. Our study provided insights into abundance and diversity of JS 1- and Chloroflexi-related bacteria in the northern SCS cold seep sediments.
基金support of R&D Program for Forest Science Technology (Project No. 2013069D10-1719-AA03) provided by Korea Forest Service (Korea Forestry Promotion Institute)
文摘The soil microbiome that plays important ecological roles in mountains and forests is influenced by anthropogenic and natural causes.Human activity,particularly harvesting or thinning,affects the soil microbiome in forests by altering environmental conditions,such as vegetation,microclimate,and soil physicochemical properties.The purpose of this study was to investigate the effects on forest thinning on the diversity and composition of the soil bacterial community.From next-generation sequencing results of the 16S rRNA gene,we examined differences in soil bacterial diversity and community composition before and after thinning at Mt.Janggunbong,South Korea.We identified 40 phyla,103 classes,192 orders,412families,947 genera,and 3,145 species from the soil samples.Acidobacteria and Proteobacteria were the most dominant bacterial phyla in the forest soil of Mt.Janggunbong.Soil bacterial diversity measures(richness,Shannon diversity index,and evenness)at the phylum level increased after thinning,whereas species-level taxonomic richness decreased after thinning.Thinning provided new opportunities for bacterial species in Chloroflexi,Verrucomicrobia,Nitrospirae,and other nondominant bacterial taxa,especially for those not found in Mt.Janggunbong before thinning,to settle and adapt to the changing environment.Our results suggested that thinning affected the diversity and composition of soil bacterial communities in forests and mountains.
文摘This study is focused on investigation of biofilms formed in an anaerobic laboratory-scale bioreactor fed with medium for anammox bacteria oxidizing ammonia with nitrite. The mixed culture of anammox bacteria was enriched from the microbial community that sampled from the activated sludge of a denitrifying reactor at a wastewater treatment station located in the Sochi region, Russia. This community forms biofilms on the surface of the flexible polymer brush carriers, which are used for biomass immobilization in both laboratory and full-scale bioreactors. Anammox bacteria were discovered in the activated sludge community. The anammox community was enriched by incubation in an up-flow laboratory-scale anaerobic bioreactor with a flexible brush carrier. In the course of ~3 years, the loading rate of nitrogen substrates (ammonium and nitrite) increased from 100 to 5000 mg N L-1 day-1. The concentration of the substrates in the upper part of the reactor was 40 times less than in the influent. The pH values were 7.5 at the bottom and up to 9 in the upper part up of the reactor. Biofilms of two types developed in the reactor. Bunches of irregular spherical granules formed on the carrier filaments, while films of irregular thickness containing submerged spherical granules were formed on the walls of reactor. The anammox population was found to consist of at least three active species: a new strain of Candidatus “Jettenia asiatica” named “strain ecos” and two species of the genus Candidatus “Brocadia”. Other types of bacteria found in the community, including members of phylum Chloroflexi, were presumably involved in biofilm spatial organization.
