The study aims to reveal phylogenetic and evolutionary relationship between aerobic anoxygenic phototrophic bacteria(AAnPB) and their relatives,anaerobic anoxygenic phototrophic bacteria(AnAnPB) and nonphototrophi...The study aims to reveal phylogenetic and evolutionary relationship between aerobic anoxygenic phototrophic bacteria(AAnPB) and their relatives,anaerobic anoxygenic phototrophic bacteria(AnAnPB) and nonphototrophic bacteria(NPB,which had high homology of 16S rDNA gene with AAnPB and fell into the same genus),and validate reliability and usefulness of farnesyl pyrophosphate synthase(FPPS) gene for the phylogenetic determination.FPPS genes with our modified primers and 16S rDNA genes with general primers,were amplified and sequenced or retrieved from GenBank database.In contrast to 16S rDNA gene phylogenetic tree,AAnPB were grouped into two clusters and one branch alone with no intermingling with NPB and AnAnPB in the tree constructed on FPPS.One branch of AAnPB,in both trees,was located closer to outgroup species than AnAnPB,which implicated that some AAnPB would be diverged earlier in FPPS evolutionary history than AnAnPB and NPB.Some AAnPB and NPB were closer located in both trees and this suggested that they were the closer relatives than AnAnPB.Combination codon usage in FPPS with phylogenetic analysis,the results indicates that FPPS gene and 16S rRNA gene have similar evolutionary pattern but the former seems to be more reliable and useful in determining the phylogenic and evolutionary relationship between AAnPB and their relatives.This is the first attempt to use a molecular marker beside 16S rRNA gene for studying the phylogeny of AAnPB,and the study may also be helpful in understanding the evolutionary relationship among phototrophic microbes and the trends of photosynthetic genes transfer.展开更多
Aerobic anoxygenic phototrophic bacteria(AAPB)repre sent a major group of bacterioplankton assemblages in many water systems and some are assumed to be closely associated with phytoplankton.However,studies on relation...Aerobic anoxygenic phototrophic bacteria(AAPB)repre sent a major group of bacterioplankton assemblages in many water systems and some are assumed to be closely associated with phytoplankton.However,studies on relationships between AAPB and cyanobacterial blooms are in scarcity.The dynamics of the abundance and diversity of AAPB was compared based on pufM gene in Meiliang Bay(featured by cyanobacterial blooms)and East Bay(featured by macrophyte)of Taihu Lake,a shallow subtropical lake in the East China plain.AAPB abundance was not significantly different between the two sites,and they were positively correlated with dissolved organic carbon(DOC)concentration.The ratios of AAPB to total bacteria varied from 3.4%to 11.5%and peaked in winter in both site s.No significant differences of AAPB community compositions were detected between the two sites,but there was a separation between warm seasons(June,August,and October)and cold seasons(December,February,and April).Rhizobiales and Limnohabitans-like pufM sequences were significantly contributors for the difference between two seasons,and specially enriched in cold seasons.Chlorophyll a(Ch1 a)and DOC were the most significant variables influencing the AAPB community structure.Furthermore,Porphyrobacter and Rhodospirillales-like pufM sequences were positively correlated with Ch1 a,indicating potential influence of cyanobacterial blooms on these AAPB taxa.These results suggested that diverse AAPB ecotypes coexisted in Taihu Lake,and their ecological role in carbon cycling in the lake may not be ignored.展开更多
High efficient removal of antibiotics during nutriments recovery for biomass production poses a major technical challenge for photosynthetic microbial biofilm-based wastewater treatment since antibiotics are always co...High efficient removal of antibiotics during nutriments recovery for biomass production poses a major technical challenge for photosynthetic microbial biofilm-based wastewater treatment since antibiotics are always co-exist with nutriments in wastewater and resist biodegradation due to their strong biotoxicity and recalcitrance.In this study,we make a first attempt to enhance metronidazole(MNZ)removal from wastewater using electrochemistry-activated binary-species photosynthetic biofilm of Rhodopseudomonas Palustris(R.Palustris)and Chlorella vulgaris(C.vulgaris)by cultivating them under different applied potentials.The results showed that application of external potentials of-0.3,0 and 0.2 V led to 11,33 and 26-fold acceleration in MNZ removal,respectively,as compared to that of potential free.The extent of enhancement in MNZ removal was positively correlated to the intensities of photosynthetic current produced under different externally applied potentials.The binary-species photoelectrogenic biofilm exhibited 18 and 6-fold higher MNZ removal rate than that of single-species of C.vulgaris and R.Palustris,respectively,due to the enhanced metabolic interaction between them.Application of an external potential of 0V significantly promoted the accumulation of tryptophan and tyrosine-like compounds as well as humic acid in ex-tracellular polymeric substance,whose concentrations were 7.4,7.1 and 2.0-fold higher than those produced at potential free,contributing to accelerated adsorption and reductive and photosensitive degradation of MNZ.展开更多
anoxygenic phototrophic bacteria (AAPB), which form a unique functional group of heterotrophic bacteria, have the abilit,to utilize light energy. The impact of carbon source and light intensity on the growth and bac...anoxygenic phototrophic bacteria (AAPB), which form a unique functional group of heterotrophic bacteria, have the abilit,to utilize light energy. The impact of carbon source and light intensity on the growth and bacteriochlorophyn a ( BChl a) expression of a typical strain of AAPB, Erythrobacter longus strain DSMZ6997 was examined during batch culture and continuous culture. The results showed that the expression of BChl a in DSMZ6997 was regulated by both carbon-source and light conditions, and was stimulated by low availability of carbon but inhibited by light to a certain extent at 300 lx and completely at 1 500 lx. In contrast, cell abundance, and even cell size of this strain, was substantially enhanced under light/dark cycle cultivation conditions over dark conditions, indicating the promotion of growth by light. These results led to the conclusion that utilization of light through BChl a helps AAPB to survive under carbon stress, while light at high intensity is harmful to the synthesis of BChl a in AAPB.展开更多
Aerobic anoxygenic phototrophic(AAP) bacteria serve important functions in marine carbon and energy cycling because of their capability to utilize dissolved organic substrates and harvest light energy.AAP bacteria a...Aerobic anoxygenic phototrophic(AAP) bacteria serve important functions in marine carbon and energy cycling because of their capability to utilize dissolved organic substrates and harvest light energy.AAP bacteria are widely distributed in marine environments,and their diversity has been examined in marine habitats.However,information about AAP bacteria at high latitudes remains insufficient to date.Therefore,this study determined the summer AAP bacterial diversity in Arctic Kongsfjorden and in the Antarctic coastal seawater of King George Island on the basis of puf M,a gene that encodes a pigment-binding protein subunit of the reaction center complex.Four puf M clone libraries were constructed,and 674 positive clones were obtained from four investigated stations(two in Kongsfjorden and two in the Antarctic Maxwell Bay).Arctic clones were clustered within the Alphaproteobacteria,whereas Antarctic clones were classified into the Alphaproteobacteria and Betaproteobacteria classes.Rhodobacteraceae-like puf M genes dominated in all samples.In addition,sequences closely related to puf M encoded on a plasmid in Sulfitobacter guttiformis were predominant in both Arctic and Antarctic samples.This result indicates the transpolar or even global distribution of puf M genes in marine environments.Meanwhile,differences between the Arctic and Antarctic sequences may prove polar endemism.These results indicate the important role of Rhodobacteraceae as AAP bacteria in bipolar coastal waters.展开更多
Lake Zigetang is located on the central Tibetan Plateau(TP) and represents a rare but typical meromictic lake in China.The lake's stable meromixis sustains microflora communities, and changes in these communities ...Lake Zigetang is located on the central Tibetan Plateau(TP) and represents a rare but typical meromictic lake in China.The lake's stable meromixis sustains microflora communities, and changes in these communities are relatively independent of climate. Therefore, these communities can be used as paleoclimate proxies. In this paper, the stratification properties and their relationships with the microflora of Lake Zigetang were analyzed. We found that water depth and climate conditions were two important factors for maintaining meromixis in Lake Zigetang. Generally, stratification was enhanced during warm periods, while temperature differences between the mixolimnion and monimolimnion were decreased during cold periods. The presence of anoxygenic phototrophic bacteria(APB) was demonstrated by the discovery of bacteriopheophytin-a(Bph-a) in the sediments.This bacterial community is mainly concentrated at the bottom of the chemocline and the top of the monimolimnion, where it forms a thin APB layer. Moreover, total APB productivity is mainly affected by the light intensity penetrating to the APB layer,which exponentially increases as the thermocline becomes shallow. Therefore, high Bph-a values in the lake corresponded to a shallow thermocline and warm periods, low Bph-a values corresponded to cold periods, and zero changes indicated that the water was completely mixed and reflected an extreme cold climate or low lake level period. Thus, Bph-a can be used as a climate proxy to reconstruct the history of lake stratification and climate changes.展开更多
基金The National Natural Science Foundation of China under contract Nos 40232021 and 40576063
文摘The study aims to reveal phylogenetic and evolutionary relationship between aerobic anoxygenic phototrophic bacteria(AAnPB) and their relatives,anaerobic anoxygenic phototrophic bacteria(AnAnPB) and nonphototrophic bacteria(NPB,which had high homology of 16S rDNA gene with AAnPB and fell into the same genus),and validate reliability and usefulness of farnesyl pyrophosphate synthase(FPPS) gene for the phylogenetic determination.FPPS genes with our modified primers and 16S rDNA genes with general primers,were amplified and sequenced or retrieved from GenBank database.In contrast to 16S rDNA gene phylogenetic tree,AAnPB were grouped into two clusters and one branch alone with no intermingling with NPB and AnAnPB in the tree constructed on FPPS.One branch of AAnPB,in both trees,was located closer to outgroup species than AnAnPB,which implicated that some AAnPB would be diverged earlier in FPPS evolutionary history than AnAnPB and NPB.Some AAnPB and NPB were closer located in both trees and this suggested that they were the closer relatives than AnAnPB.Combination codon usage in FPPS with phylogenetic analysis,the results indicates that FPPS gene and 16S rRNA gene have similar evolutionary pattern but the former seems to be more reliable and useful in determining the phylogenic and evolutionary relationship between AAnPB and their relatives.This is the first attempt to use a molecular marker beside 16S rRNA gene for studying the phylogeny of AAnPB,and the study may also be helpful in understanding the evolutionary relationship among phototrophic microbes and the trends of photosynthetic genes transfer.
基金Supported by the National Natural Science Foundation of China(Nos.31971449,31370509,31100363)the CAS-SAFEA International Partnership Program for Creative Research Teams(CN)(No.KZZD-EWTZ-08)the startup funds from Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences(No.NIGLAS2011QD05)。
文摘Aerobic anoxygenic phototrophic bacteria(AAPB)repre sent a major group of bacterioplankton assemblages in many water systems and some are assumed to be closely associated with phytoplankton.However,studies on relationships between AAPB and cyanobacterial blooms are in scarcity.The dynamics of the abundance and diversity of AAPB was compared based on pufM gene in Meiliang Bay(featured by cyanobacterial blooms)and East Bay(featured by macrophyte)of Taihu Lake,a shallow subtropical lake in the East China plain.AAPB abundance was not significantly different between the two sites,and they were positively correlated with dissolved organic carbon(DOC)concentration.The ratios of AAPB to total bacteria varied from 3.4%to 11.5%and peaked in winter in both site s.No significant differences of AAPB community compositions were detected between the two sites,but there was a separation between warm seasons(June,August,and October)and cold seasons(December,February,and April).Rhizobiales and Limnohabitans-like pufM sequences were significantly contributors for the difference between two seasons,and specially enriched in cold seasons.Chlorophyll a(Ch1 a)and DOC were the most significant variables influencing the AAPB community structure.Furthermore,Porphyrobacter and Rhodospirillales-like pufM sequences were positively correlated with Ch1 a,indicating potential influence of cyanobacterial blooms on these AAPB taxa.These results suggested that diverse AAPB ecotypes coexisted in Taihu Lake,and their ecological role in carbon cycling in the lake may not be ignored.
基金The authors thank the financial support provided by the National Natural Science Foundation of China(No.51108186)the Tip-top Scientific and Technical Innovative Youth Talents of Guangdong Special Support Program,China(No.2015TQ01Z039)the Natural Science Research Project of Higher Education Institutions of Guangdong Province(No.2015KTSCX025).
文摘High efficient removal of antibiotics during nutriments recovery for biomass production poses a major technical challenge for photosynthetic microbial biofilm-based wastewater treatment since antibiotics are always co-exist with nutriments in wastewater and resist biodegradation due to their strong biotoxicity and recalcitrance.In this study,we make a first attempt to enhance metronidazole(MNZ)removal from wastewater using electrochemistry-activated binary-species photosynthetic biofilm of Rhodopseudomonas Palustris(R.Palustris)and Chlorella vulgaris(C.vulgaris)by cultivating them under different applied potentials.The results showed that application of external potentials of-0.3,0 and 0.2 V led to 11,33 and 26-fold acceleration in MNZ removal,respectively,as compared to that of potential free.The extent of enhancement in MNZ removal was positively correlated to the intensities of photosynthetic current produced under different externally applied potentials.The binary-species photoelectrogenic biofilm exhibited 18 and 6-fold higher MNZ removal rate than that of single-species of C.vulgaris and R.Palustris,respectively,due to the enhanced metabolic interaction between them.Application of an external potential of 0V significantly promoted the accumulation of tryptophan and tyrosine-like compounds as well as humic acid in ex-tracellular polymeric substance,whose concentrations were 7.4,7.1 and 2.0-fold higher than those produced at potential free,contributing to accelerated adsorption and reductive and photosensitive degradation of MNZ.
基金This study was supported by the National Natural Science Foundation of China under contract Nos 40232021,40576063 and 40521003the Ministry of Science and Technology of China under contract Nos 2005AA635240 and 2003DF000040.
文摘anoxygenic phototrophic bacteria (AAPB), which form a unique functional group of heterotrophic bacteria, have the abilit,to utilize light energy. The impact of carbon source and light intensity on the growth and bacteriochlorophyn a ( BChl a) expression of a typical strain of AAPB, Erythrobacter longus strain DSMZ6997 was examined during batch culture and continuous culture. The results showed that the expression of BChl a in DSMZ6997 was regulated by both carbon-source and light conditions, and was stimulated by low availability of carbon but inhibited by light to a certain extent at 300 lx and completely at 1 500 lx. In contrast, cell abundance, and even cell size of this strain, was substantially enhanced under light/dark cycle cultivation conditions over dark conditions, indicating the promotion of growth by light. These results led to the conclusion that utilization of light through BChl a helps AAPB to survive under carbon stress, while light at high intensity is harmful to the synthesis of BChl a in AAPB.
基金The National Natural Science Foundation of China under contract Nos 41076131and 41476171the Chinese Polar Environment Comprehensive Investigation and Assessment Program under contract Nos CHINARE2015-02-01 and CHINARE2015-04-01
文摘Aerobic anoxygenic phototrophic(AAP) bacteria serve important functions in marine carbon and energy cycling because of their capability to utilize dissolved organic substrates and harvest light energy.AAP bacteria are widely distributed in marine environments,and their diversity has been examined in marine habitats.However,information about AAP bacteria at high latitudes remains insufficient to date.Therefore,this study determined the summer AAP bacterial diversity in Arctic Kongsfjorden and in the Antarctic coastal seawater of King George Island on the basis of puf M,a gene that encodes a pigment-binding protein subunit of the reaction center complex.Four puf M clone libraries were constructed,and 674 positive clones were obtained from four investigated stations(two in Kongsfjorden and two in the Antarctic Maxwell Bay).Arctic clones were clustered within the Alphaproteobacteria,whereas Antarctic clones were classified into the Alphaproteobacteria and Betaproteobacteria classes.Rhodobacteraceae-like puf M genes dominated in all samples.In addition,sequences closely related to puf M encoded on a plasmid in Sulfitobacter guttiformis were predominant in both Arctic and Antarctic samples.This result indicates the transpolar or even global distribution of puf M genes in marine environments.Meanwhile,differences between the Arctic and Antarctic sequences may prove polar endemism.These results indicate the important role of Rhodobacteraceae as AAP bacteria in bipolar coastal waters.
基金supported by the Chinese Academy of Sciences Strategic Priority Research Program(Grant No.XDA05080402)the National Natural Science Foundation of China(Grant No.41361008)+1 种基金Yunnan Provincial Government Leading Scientist Program(Grant No.2015HA024)Yunnan Provincial Government Senior Talent Program(Grant No.2010CI111)
文摘Lake Zigetang is located on the central Tibetan Plateau(TP) and represents a rare but typical meromictic lake in China.The lake's stable meromixis sustains microflora communities, and changes in these communities are relatively independent of climate. Therefore, these communities can be used as paleoclimate proxies. In this paper, the stratification properties and their relationships with the microflora of Lake Zigetang were analyzed. We found that water depth and climate conditions were two important factors for maintaining meromixis in Lake Zigetang. Generally, stratification was enhanced during warm periods, while temperature differences between the mixolimnion and monimolimnion were decreased during cold periods. The presence of anoxygenic phototrophic bacteria(APB) was demonstrated by the discovery of bacteriopheophytin-a(Bph-a) in the sediments.This bacterial community is mainly concentrated at the bottom of the chemocline and the top of the monimolimnion, where it forms a thin APB layer. Moreover, total APB productivity is mainly affected by the light intensity penetrating to the APB layer,which exponentially increases as the thermocline becomes shallow. Therefore, high Bph-a values in the lake corresponded to a shallow thermocline and warm periods, low Bph-a values corresponded to cold periods, and zero changes indicated that the water was completely mixed and reflected an extreme cold climate or low lake level period. Thus, Bph-a can be used as a climate proxy to reconstruct the history of lake stratification and climate changes.