Biofouling, the accumulation of microorganisms, is a major problem in paper mills processing paper and cardboard. This leads to the production of lower quality recycled products. Several studies have focused on the mi...Biofouling, the accumulation of microorganisms, is a major problem in paper mills processing paper and cardboard. This leads to the production of lower quality recycled products. Several studies have focused on the microbial content in the paper mill and the final products. Our aim was to determine the microbial biota in a bale of collected cardboard prior to entering the paper mill. Total genomic DNA was isolated and analyzed using two different methods for comparison purposes: 454 pyrosequencing and clone library. A total of 3268 V6-V8 454 pyrosequencing reads and 322 cloned V6-V8 16S rRNA nucleotide sequences were obtained. Both methods showed the presence of three major bacterial genera: Bacillus, Solibacillus and Paenibacillus, all members of the spore-forming phylum Firmicutes. Pyrosequencing, however, revealed a richer and more diverse bacterial community than clone library. It showed the presence of additional minor Firmicute genera and of a small number of Proteobacteria. The sorting at the recycling plant, the storing, and the processing at the paper mill, the end uses, will all contribute to the bacterial microbiota present in a bale of collected cardboard as revealed here.展开更多
Biological risks of bioaerosols emitted from wastewater treatment processes have attracted wide attention in the recent years. However, the culture-based analysis method has been mostly adopted for detecting the bacte...Biological risks of bioaerosols emitted from wastewater treatment processes have attracted wide attention in the recent years. However, the culture-based analysis method has been mostly adopted for detecting the bacterial community in bioaerosols, which may result in the underestimation of total microorganism concentration as not all microorganisms are cultivable. In this study, oligonucleotide fingerprinting of 16S rRNA genes was applied to reveal the composition and structure of the bacterial community in bioaerosols from an Orbal oxidation ditch in a Beijing wastewater treatment plant （WWTP）. Bioaerosols were collected at different distances from the aerosol source, rotating brushes, and the sampling height was 1.5 m which is the common respiratory height of a human being. The bacterial communities of bioaerosols were diverse, and the lowest bacterial diversity was found at the sampling site just after the rotating brush rotating brush. A large proportion of bacteria in bioaerosols were affiliated with Proteobacteria and Bacteroidetes. Numerous bacteria present in the bioaerosols also emerged in water, indicating that the bacterial community in the bioaerosols was related to that of the aerosols＇ sources. The forced aeration of rotating brushes brought about observably distinct bacterial communities between sampling sites situated before and after the rotating brush. Isolation sources of closest relatives in bioaerosols clone libraries were associated with the aqueous environment in the WWTP. Common potential pathogens in bioaerosols as well as those not reported in previous research were also analyzed in this study. Measures should be adopted to reduce the emission of bioaerosols and prevent their exposure to workers.展开更多
Objective To construct human myeloma cell cDNA expression library as to screen myeloma tumor antigen. Methods Total RNA and purified mRNA were extracted from human myeloma cell line HMy2. First and second strand cDNA ...Objective To construct human myeloma cell cDNA expression library as to screen myeloma tumor antigen. Methods Total RNA and purified mRNA were extracted from human myeloma cell line HMy2. First and second strand cDNA were synthesized through reverse transcription. After blunting, the cDNA fragments were ligated with EcoR I adapters. Then the cDNAs were digested by Xho I, and smaller than 400bp were removed by Sephacryl-S400 spin column, the remaining were ligated with λZAP vector. The recombinants were packaged in vitro, and a small portion of packaged phage was used to infect E.coli XL1-Blue-MRF for titration. The recombinants were examined by color selection. In order to evaluate the size of cDNA inserts and the diversity of library, the pBK-CMV phagemid were excised from the ZAP express vector by using ExAssist helper phage with XLOLR strain , and then the pBK-CMV phagemid were digested by Xho I and EcoR I. Results The HMy2 cell line cDNA library consisting of 1.58×10 6 recombinant bacteriophages was constructed with the recombinant ratio 99.6%. The average length of the recombinant exogenous inserts was about 1.7kb.Conclusion The constructed cDNA library are deserved to screen target clones.展开更多
To expand knowledge on microbial communities of various metal-rich levels of mine drainage environments in Anhui province, China, the archaeal and bacterial diversities were examined using a PCR-based cloning approach...To expand knowledge on microbial communities of various metal-rich levels of mine drainage environments in Anhui province, China, the archaeal and bacterial diversities were examined using a PCR-based cloning approach. Eight acid mine water samples were collected from five areas in Tongling. Phylogenetic analyses revealed that bacteria mainly fell into ten divisions, which were Betaproteobacteria, Gammaproteobacteria, Alphaproteobacteria, Deinococcus-Thermus, Nitrospira, Firmicutes, Actinobacteria, Deltaproteobacteria, Bacteroidetes, Chloroflexi. Archaea fell into three phylogenetic divisions, Thermoplasma, Ferroplasma and Thermogymnomonas. The unweighted pair group method with arithmetic mean（UPGMA） cluster analysis based on the microbial communities’ compositions revealed that five samples shared similarity with the dominance of Meiothermus and Thermomonas. Two samples had the preponderant existence of Acidithiobacillus and Leptospirillum. The remaining sample owned higher microbial communities’ diversity with the Shannon-Weaver H up to 2.91. Canonical correlation analysis（CCA） suggested that microbial community structures had great association with p H and the concentration of Hg2＋, Pb2＋, Fe3＋, Cl-, SO2- 4in water.展开更多
Taking two important agricultural soils with different pH, brown soil （Hap-Udic Luvisol） and cinnamon soil （Hap-Ustic Luvisol）, from Northeast China, a pot culture experiment with spring maize （Zea mays L.） was ...Taking two important agricultural soils with different pH, brown soil （Hap-Udic Luvisol） and cinnamon soil （Hap-Ustic Luvisol）, from Northeast China, a pot culture experiment with spring maize （Zea mays L.） was conducted to study the dynamic changes in the abundance and diversity of soil ammonia-oxidizing bacteria （AOB） and ammonia-oxidizing archaea （AOA） populations during maize growth period in response to the additions of nitrification inhibitors dicyandiamide （DCD） and 3,4-dimethylpyrazole phosphate （DMPP） by the methods of real-time polymerase chain reaction （PCR） assay, PCR-denaturing gradient gel electrophoresis （DGGE）, and construction of clone library targeting the amoA gene. Four treatments were established, i.e., no urea （control）, urea, urea plus DCD, and urea plus DMPP. Both DCD and DMPP inhibited growth of AOB significantly, compared to applying urea alone. Soil bacterial amoA gene copies had a significant positive linear correlation with soil nitrate content, but soil archaeal amoA gene copies did not. In both soils, all AOB sequences fell within Nitrosospira or Nitrosospira-like groups, and all AOA sequences belonged to group 1.1b crenaxchaea. With the application of DCD or DMPP, community composition of AOB and AOA in the two soils had less change except that the AOB community composition in Hap-Udic Luvisol changed at the last two growth stages of maize under the application of DCD. AOB rather than AOA likely dominated soil ammonia oxidation in these two agricultural soils.展开更多
The bacterial community of a bulking sludge from a municipal wastewater treatment plant with anoxic-anaerobic-oxic process was investigated by combination of cultivation and 16S rRNA gene clone library analysis for un...The bacterial community of a bulking sludge from a municipal wastewater treatment plant with anoxic-anaerobic-oxic process was investigated by combination of cultivation and 16S rRNA gene clone library analysis for understanding the causes of bulking.A total of 28 species were obtained from 63 isolates collected from six culture media.The most cultivable species belonged to γ-Proteobacteria including Klebsiella sp.,Pseudomonas sp.,Aeromonas sp.and Acinetobacter sp.Further analysis of these strains by repetitive sequence based on polymerase chain reaction （rep-PCR） technology showed that rep-PCR yielded discriminatory banding patterns within the same genus using REP and BOX primer sets.While the culture-independent assessment revealed that β-Proteobacteria was the dominant group in the bulking sample.Sequence analysis revealed that the highest proportion （14.7%） of operational taxonomic units was 98% similar to Candidatus Accumulibacter phosphatis,which is used to remove phosphorous from wastewater.Our results indicated that combining different approaches can produce complementary information,thus generate a more accurate view of microbial community in bulking sludge.展开更多
This study evaluated the microbial community dynamics and maturation time of two compost systems： biogas slurry compost and cow manure compost, with the aim of evaluating the potential utility of a biogas slurry comp...This study evaluated the microbial community dynamics and maturation time of two compost systems： biogas slurry compost and cow manure compost, with the aim of evaluating the potential utility of a biogas slurry compost system. Denaturing gradient gel electrophoresis （DGGE）, gene clone library, temperature, C/N ratio, and the germination index were employed for the investigation, cow manure compost was used as the control. Results showed that the basic strip and dominant strips of the DGGE bands for biogas slurry compost were similar to those of cow manure compost, but the brightness of the respective strips for each system were different. Shannon-Weaver indices of the two compost systems differed, possessing only 22% similarity in the primary and maturity stages of the compost process. Using bacterial 16S rRNA gene clone library analysis, 88 bacterial clones were detected. Further, 18 and 13 operational taxonomic units （OTUs） were present in biogas slurry and cow manure compost, respectively. The 18 OTUs of the biogas slurry compost belonged to nine bacterial genera, of which the dominant strains were Bacillus sp. and Carnobacterium sp.; the 13 OTUs of the cow manure compost belonged to eight bacterial genera, of which the dominant strains were Psychrobacter sp., Pseudomonas sp., and Clostridium sp. Results demonstrated that the duration of the thermophilic phase （more than 50°C） for biogas slurry compost was 8 d less than the according duration for cow manure compost, and the maturation times for biogas slurry and cow manure compost were 45 and 60 d, respectively. It is an effective biogas slurry assimilate technology by application of biogas slurry as nitrogen additives in the manufacture of organic fertilizer.展开更多
Bioaerosols from wastewater treatment processes are a significant subgroup of atmospheric aerosols. In the present study,airborne microorganisms generated from a wastewater treatment station（WWTS） that uses an oxida...Bioaerosols from wastewater treatment processes are a significant subgroup of atmospheric aerosols. In the present study,airborne microorganisms generated from a wastewater treatment station（WWTS） that uses an oxidation ditch process were diminished by ventilation.Conventional sampling and detection methods combined with cloning/sequencing techniques were applied to determine the groups,concentrations,size distributions,and species diversity of airborne microorganisms before and after ventilation. There were 3021 ± 537 CFU/m3 of airborne bacteria and 926 ± 132 CFU/m3 of airborne fungi present in the WWTS bioaerosol.Results showed that the ventilation reduced airborne microorganisms significantly compared to the air in the WWTS. Over 60% of airborne bacteria and airborne fungi could be reduced after4 hr of air exchange. The highest removal（92.1% for airborne bacteria and 89.1% for fungi） was achieved for 0.65–1.1 μm sized particles. The bioaerosol particles over 4.7 μm were also reduced effectively. Large particles tended to be lost by gravitational settling and small particles were generally carried away,which led to the relatively easy reduction of bioaerosol particles0.65–1.1 μm and over 4.7 μm in size. An obvious variation occurred in the structure of the bacterial communities when ventilation was applied to control the airborne microorganisms in enclosed spaces.展开更多
Fungicides have been used extensively for controlling fungal pathogens of plants. However, little is known regarding the effects that fungicides upon the indigenous bacterial communities within the plant phyllosphere....Fungicides have been used extensively for controlling fungal pathogens of plants. However, little is known regarding the effects that fungicides upon the indigenous bacterial communities within the plant phyllosphere. The aims of this study were to assess the impact of fungicide enostroburin upon bacterial communities in wheat phyllosphere. Culture-independent methodologies of 16S rDNA clone library and 16S rDNA directed polymerase chain reaction with denaturing gradient gel electrophoresis （PCR-DGGE） were used for monitoring the change of bacterial community. The 16S rDNA clone library and PCR-DGGE analysis both confirmed the microbial community of wheat plant phyllosphere were predominantly of the γ-Proteobacteria phyla. Results from PCR-DGGE analysis indicated a significant change in bacterial community structure within the phyllosphere following fungicide enostroburin application. Bands sequenced within control cultures were predominantly of Pseudomonas genus, but those bands sequenced in the treated samples were predominantly strains of Pantoea genus and Pseudomonas genus. Of interest was the appearance of two DGGE bands following fungicide treatment, one of which had sequence similarities （98%） to Pantoea sp. which might be a competitor of plant pathogens. This study revealed the wheat phyllosphere bacterial community composition and a shift in the bacterial community following fungicide enostroburin application.展开更多
The response of archaeal communities to petroleum contamination in saline-alkali soil was characterized by analyses of three soil samples with different total petroleum hydrocarbon concentrations.Through the construct...The response of archaeal communities to petroleum contamination in saline-alkali soil was characterized by analyses of three soil samples with different total petroleum hydrocarbon concentrations.Through the construction and screening of 16S rRNA gene clone libraries based on DNA extracts from these soils,nine distinct phylogenetic groups were identified.Statistical analyses showed that the distribution of archaeal community structures differ significantly along the gradient of petroleum contamination in these three saline- alkali soils.Five phylogenetic groups were dominant in the control soil,two of which were also abundant in the lightly contaminated soil.Four phylogenetic groups were dominant in heavily contaminated soil,one of which was also abundant in the lightly contaminated soil.The halophilic genus of Haloferax and the haloalkaliphilic genus of Natronomonas were more abundant in heavily contaminated soil.These results suggested that the genera of Haloferax and Natronomonas may have a role in the natural attenuation of petroleum- contaminated saline-alkali soil.展开更多
Fungistasis is one of the important approaches to control soil-borne plant pathogens.Some hypotheses about the mechanisms for soil fungistasis had been established,which mainly focused on the soil bacterial community ...Fungistasis is one of the important approaches to control soil-borne plant pathogens.Some hypotheses about the mechanisms for soil fungistasis had been established,which mainly focused on the soil bacterial community composition,structure,diversity as well as function.In this study,the bacterial community composition and diversity of a series of soils treated by autoclaving,which coming from the same original soil sample and showing gradient fungistasis to the target soil-borne pathogen fungi Fusarium grami...展开更多
To better understand the effect of salinity on denitrification communities, soils along a salinity gradient （ranging from 7.32 to 1.70 mS cm 1） in a wetland along the Yellow Sea coastline in Jiangsu Province, China,...To better understand the effect of salinity on denitrification communities, soils along a salinity gradient （ranging from 7.32 to 1.70 mS cm 1） in a wetland along the Yellow Sea coastline in Jiangsu Province, China, were studied using both culture-dependent and -independent methods. Culture efforts yielded 82 isolates in total, 81.7% of which were close relatives of Bacillus sp. based on partial sequences of their 16S rRNA genes. Denaturing gradient gel electrophoresis （DGGE） analysis based on 16S rRNA sequences suggested possible existence of bacterial community succession along the salinity gradient. Clone library analysis based on nosZ gene sequences （coding nitrous oxide reductase） showed that operational taxonomic units （OTUs） associated with α-proteobacteria dominated in all three soils, whereas those associated with β- and γ-subdivisions showed a clear succession. In the high salinity soil, only the OTUs associated with a-subdivision were found. In the medium salinity soil, small proportions of β- （6.5%） and γ-associated （19.6%） OTUs were found. In the low salinity soil, the proportions were further increased to 33% and 25% for β- and γ-Proteobacteria, respectively. Statistic analysis using Unifrac P test showed that nosZ-communities in different saline soils were significantly different from each other. It could be concluded that α-subdivision of nosZ-community tended to be sustained in high salinity environments whereas β and γ-subdivisions, especially the former, tended to be sustained in low salinity environments. Salinity was the key determinant of nosZ-community composition in the environment.展开更多
The microbial community structures in an integrated two-phase anaerobic reactor（ITPAR）were investigated by 16 S r DNA clone library technology. The 75 L reactor was designed with a 25 L rotating acidogenic unit at t...The microbial community structures in an integrated two-phase anaerobic reactor（ITPAR）were investigated by 16 S r DNA clone library technology. The 75 L reactor was designed with a 25 L rotating acidogenic unit at the top and a 50 L conventional upflow methanogenic unit at the bottom, with a recirculation connected to the two units. The reactor had been operated for 21 stages to co-digest fruit/vegetable wastes and wheat straw, which showed a very good biogas production and decomposition of cellulosic materials. The results showed that many kinds of cellulose and glycan decomposition bacteria related with Bacteroidales,Clostridiales and Syntrophobacterales were dominated in the reactor, with more bacteria community diversities in the acidogenic unit. The methanogens were mostly related with Methanosaeta, Methanosarcina, Methanoculleus, Methanospirillum and Methanobacterium; the predominating genus Methanosaeta, accounting for 40.5%, 54.2%, 73.6% and 78.7% in four samples from top to bottom, indicated a major methanogenesis pathway by acetoclastic methanogenesis in the methanogenic unit. The beta diversity indexes illustrated a more similar distribution of bacterial communities than that of methanogens between acidogenic unit and methanogenic unit. The differentiation of methanogenic community composition in two phases, as well as pH values and volatile fatty acid（VFA） concentrations confirmed the phase separation of the ITPAR. Overall, the results of this study demonstrated that the special designing of ITPAR maintained a sufficient number of methanogens, more diverse communities and stronger syntrophic associations among microorganisms, which made two phase anaerobic digestion of cellulosic materials more efficient.展开更多
The anaerobic ammonium oxidation （anammox） process was successfully started up from conventional activated sludge using a hybrid bioreactor within 2 months.The average removal efficiencies of ammonia and nitrite wer...The anaerobic ammonium oxidation （anammox） process was successfully started up from conventional activated sludge using a hybrid bioreactor within 2 months.The average removal efficiencies of ammonia and nitrite were both over 80%,and the maximum total nitrogen removal rate of 1.85 kg N/（m^3 ·day） was obtained on day 362 with the initial sludge concentration of 0.7 g mixed liquor suspended solids （MLSS）/L.Scanning electron microscope （SEM） observation of the granular sludge in the hybrid reactor clearly showed a high degree of compactness and cell sphericity,and the cell size was quite uniform.Transmission electron microscope photos showed that cells were round or oval,the cellular diameter was 0.6-1.0 μm,and the percentage of the anammoxosome compartment was 51%-85% of the whole cell volume.Fluorescence in situ hybridization analysis （FISH） indicated that anammox bacteria became the dominant population in the community （accounting for more than 51% of total bacteria on day 250）.Seven planctomycete 16S rRNA gene sequences were present in the 16S rRNA gene clone library generated from the biomass and affiliated to Candidatus Kuenenia stuttgartiensis and Candidatus Brocadia sp.,a new anammox species.In addition,the average effluent suspended solid （MLSS） concentrations of outlets I （above the non-woven carrier） and II （below the non-woven carrier） were 0.0009 and 0.0035 g/L,respectively.This showed that the non-woven carrier could catch the biomass effectively,which increased biomass and improved the nitrogen removal rate in the reactor.展开更多
Seashore landfill aquifers are environments of special physicochemical conditions (high organic load and high sa- linity), and microbes in leachate-polluted aquifers play a significant role for intrinsic bioremediatio...Seashore landfill aquifers are environments of special physicochemical conditions (high organic load and high sa- linity), and microbes in leachate-polluted aquifers play a significant role for intrinsic bioremediation. In order to characterize microbial diversity and look for clues on the relationship between microbial community structure and hydrochemistry, a cul- ture-independent examination of a typical groundwater sample obtained from a seashore landfill was conducted by sequence analysis of 16S rDNA clone library. Two sets of universal 16S rDNA primers were used to amplify DNA extracted from the groundwater so that problems arising from primer efficiency and specificity could be reduced. Of 74 clones randomly selected from the libraries, 30 contained unique sequences whose analysis showed that the majority of them belonged to bacteria (95.9%), with Proteobacteria (63.5%) being the dominant division. One archaeal sequence and one eukaryotic sequence were found as well. Bacterial sequences belonging to the following phylogenic groups were identified: Bacteroidetes (20.3%), β, γ, δ and ε-subdivisions of Proteobacteria (47.3%, 9.5%, 5.4% and 1.3%, respectively), Firmicutes (1.4%), Actinobacteria (2.7%), Cyanobacteria (2.7%). The percentages of Proteobacteria and Bacteroides in seawater were greater than those in the groundwater from a non-seashore landfill, indicating a possible influence of seawater. Quite a few sequences had close relatives in marine or hypersaline environments. Many sequences showed affiliations with microbes involved in anaerobic fermentation. The remarkable abundance of sequences related to (per)chlorate-reducing bacteria (ClRB) in the groundwater was significant and worthy of further study.展开更多
The bacterial diversity of activated slud ge from submerged membrane bioreactor(SMBR)was investigated.A 16S rDNA clone library was generated,and 150 clones were screened using restriction frag ment length poly morp hi...The bacterial diversity of activated slud ge from submerged membrane bioreactor(SMBR)was investigated.A 16S rDNA clone library was generated,and 150 clones were screened using restriction frag ment length poly morp hism(RFLP).Of the screened clones,almost full-leng th 16S rDNA sequences of 64 clones were sequenced.Phy lo genetic tree was constructed with a database containing clone sequences from this study and bacterial rDNA sequen ces from NCBI for identification purposes.The 90.6%of the clones were affi liated with the two phy la Bacteroidetes(50%)and Proteobacteria(40%),and β-,γ-and δ-Proteobacteria acco unted for 7.8%,28.1%,and 4.7%,respectively.Minor portions were affiliated with the Actinobacteria and Firmicutes(both 3.1%).Only 6 out of 6416S rDNA sequences exhibited simil arities of more than 97%to classifed bacterial species,which indicated that a substantial fraction of the clone sequences were deri ved from unkno wn tax a.Rarefaction analysis of operational taxonomic units(OTUs)clusters demonstrated that 150 clones screened were still insuffi cient to describe the whole bacterial diversity.Measurement of water quality parameter demonstrated that performance of the SMBR maintained hig h level,and the SMBR sy stem remained stable during this study.展开更多
Ammonia-oxidizing archaea （AOA） are widely considered key to ammonia oxidation in various environments. However, little work has been conducted to simultaneously investigate the abundance and diversity of AOA as wel...Ammonia-oxidizing archaea （AOA） are widely considered key to ammonia oxidation in various environments. However, little work has been conducted to simultaneously investigate the abundance and diversity of AOA as well as correlations between archaeal amoA genotypes and environmental parameters of different ecosystems at one district. To understand the abundance, diversity, and distribution of AOA in Pearl River Delta of China in response to various habitats, the archaeal amoA genes in soil, marine, river, lake, hot spring and wastewater treatment plant （WWTP） samples were investigated using real-time fluorescent quantitative PCR and clone libraries. Our analyses indicated that the diversity of AOA in various habitats was different and could be clustered into five major clades, i.e., estuary sediment, marine water/sediment, soil, hot spring and Cluster 1. Phylogenetic analyses revealed that the structure of AOA communities in similar ecological habitats exhibited strong relation. The canonical correspondence method indicated that the AOA community structure was strongly correlated to temperature, pH, total organic carbon, total nitrogen and dissolved oxygen variables. Assessing AOA amoA gene copy numbers, ranging from 6.84× 10^6 to 9.45 × 10^7 copies/g in dry soil/sediment, and 6.06× 10^6 to 2.41 ×10^7 copies/L in water samples, were higher than ammonia-oxidizing bacteria （AOB） by 1-2 orders of magnitude. However, AOA amoA copy numbers were much lower than AOB in WWTP activated sludge samples. Overall, these studies suggested that AOA may be a major contributor to ammonia oxidation in natural habitats but play a minor role in highly aerated activated sludge. The result also showed the ratio of AOA to AOB amoA gene abundance was positively correlated with temperature and less correlated with other environmental parameters. New data from our study provide increasing evidence for the relative abundance and diversity of ammonia-oxidizing archaea in the global nitrogen cycle.展开更多
Objective To compare the bacterioplankton communities in streams exposed to pollution of different types. Methods The bacterioplankton communities in three selected heavily polluted streams were investigated by using ...Objective To compare the bacterioplankton communities in streams exposed to pollution of different types. Methods The bacterioplankton communities in three selected heavily polluted streams were investigated by using terminal‐restriction fragment length polymorphism （T‐RFLP） analysis in combination with 16S rRNA gene clone library analysis. Results Both T‐RFLP and 16S rRNA gene clone library revealed a great difference in bacterioplankton community composition in the different streams. Conclusion This work might provide some new insights into bioremediation of heavily polluted streams.展开更多
Phylogenetic diversity of Form I and Form II ribulose1, 5-bisphosphate carboxylase/oxygenase (RubisCO) largesubunit (rbcL) genes in the inshore and offshore areas of the East China Sea were investigated. Two new prime...Phylogenetic diversity of Form I and Form II ribulose1, 5-bisphosphate carboxylase/oxygenase (RubisCO) largesubunit (rbcL) genes in the inshore and offshore areas of the East China Sea were investigated. Two new primer setswere designed for amplifying partial sequences of rbcL genes from Proteobacteria. Four rbcL gene clone libraries wereconstructed by amplification and cloning of approximately 640~800 bp sequences of bacterioplankton populations.The method of screening library by denaturing gradient gel electrophoresis (DGGE) was introduced. The resultsshow that the diversity of Form I is higher in offshore waters with higher salinity and lower productivity, while thatof Form II is higher at the inshore station where salinity is lower and productivity is higher. Several clusters ofsequences obtained are deeply rooted and show low similarity (60%~78%) to the known rbcL in existing databases.The degree of diversity of rbcL genes is directly related to environmental variables, including temperature, salinity,pH, dissolved oxygen, etc. These results indicate that rbcL gene can be used as an effective indicator for geneticdiversity and population variability of bacterioplankton with the ability of carbon dioxide fixation in the sea.展开更多
Micro-communities are supposed to have more potential functions of biodegradation of polysaccharides than single strain; however, the intestinal mi ties involved in the biodegradation of Enteromorpha polysaccharides ...Micro-communities are supposed to have more potential functions of biodegradation of polysaccharides than single strain; however, the intestinal mi ties involved in the biodegradation of Enteromorpha polysaccharides （EP） were sel- dom reported. In order to obtain the EP-degrading micro-community, the intestines of Siganus oramin was obtained to isolate the micro-communities, which were enriched by 0.3% of EP as the sole carbon source. A stable micro-community with EP degradative capability was achieved after seven generations of subculture, named H1. Results showed that H1 was able to degrade 75% of EP within 24 hours, and the activity of EP lyases reached 500 U mL-1 in 32 hours. With denaturing gradient gel electrophoresis （DGGE） and 16S rRNA gene clone library analysis, ten bacteria closely related to Marinomonas pontica, Microbacterium sp., Leucobacter chironomi, Cyclobacterium sp., Algoriphagus winogradskyi, Pseudoalteromonas sp. and Vibrio sp. were determined. Furthermore, compared with the DGGE bands sequence and the clone library analysis, the dominant bacteria of the EP-biodegrading mi- cro-community were Pseudoalteromonas sp. and Vibrio sp., with the respective proportion of 38% and 46%, and they should play an important role in EP degradation together with other degrading bacteria in the micro-community H1.展开更多
基金supported in part by the Natural Sciences and Engineering Research Council of Canada(grant EGP 436904-12).
文摘Biofouling, the accumulation of microorganisms, is a major problem in paper mills processing paper and cardboard. This leads to the production of lower quality recycled products. Several studies have focused on the microbial content in the paper mill and the final products. Our aim was to determine the microbial biota in a bale of collected cardboard prior to entering the paper mill. Total genomic DNA was isolated and analyzed using two different methods for comparison purposes: 454 pyrosequencing and clone library. A total of 3268 V6-V8 454 pyrosequencing reads and 322 cloned V6-V8 16S rRNA nucleotide sequences were obtained. Both methods showed the presence of three major bacterial genera: Bacillus, Solibacillus and Paenibacillus, all members of the spore-forming phylum Firmicutes. Pyrosequencing, however, revealed a richer and more diverse bacterial community than clone library. It showed the presence of additional minor Firmicute genera and of a small number of Proteobacteria. The sorting at the recycling plant, the storing, and the processing at the paper mill, the end uses, will all contribute to the bacterial microbiota present in a bale of collected cardboard as revealed here.
基金supported by the National Natural Science Foundation of China (No.51178451,51138009)
文摘Biological risks of bioaerosols emitted from wastewater treatment processes have attracted wide attention in the recent years. However, the culture-based analysis method has been mostly adopted for detecting the bacterial community in bioaerosols, which may result in the underestimation of total microorganism concentration as not all microorganisms are cultivable. In this study, oligonucleotide fingerprinting of 16S rRNA genes was applied to reveal the composition and structure of the bacterial community in bioaerosols from an Orbal oxidation ditch in a Beijing wastewater treatment plant （WWTP）. Bioaerosols were collected at different distances from the aerosol source, rotating brushes, and the sampling height was 1.5 m which is the common respiratory height of a human being. The bacterial communities of bioaerosols were diverse, and the lowest bacterial diversity was found at the sampling site just after the rotating brush rotating brush. A large proportion of bacteria in bioaerosols were affiliated with Proteobacteria and Bacteroidetes. Numerous bacteria present in the bioaerosols also emerged in water, indicating that the bacterial community in the bioaerosols was related to that of the aerosols＇ sources. The forced aeration of rotating brushes brought about observably distinct bacterial communities between sampling sites situated before and after the rotating brush. Isolation sources of closest relatives in bioaerosols clone libraries were associated with the aqueous environment in the WWTP. Common potential pathogens in bioaerosols as well as those not reported in previous research were also analyzed in this study. Measures should be adopted to reduce the emission of bioaerosols and prevent their exposure to workers.
文摘Objective To construct human myeloma cell cDNA expression library as to screen myeloma tumor antigen. Methods Total RNA and purified mRNA were extracted from human myeloma cell line HMy2. First and second strand cDNA were synthesized through reverse transcription. After blunting, the cDNA fragments were ligated with EcoR I adapters. Then the cDNAs were digested by Xho I, and smaller than 400bp were removed by Sephacryl-S400 spin column, the remaining were ligated with λZAP vector. The recombinants were packaged in vitro, and a small portion of packaged phage was used to infect E.coli XL1-Blue-MRF for titration. The recombinants were examined by color selection. In order to evaluate the size of cDNA inserts and the diversity of library, the pBK-CMV phagemid were excised from the ZAP express vector by using ExAssist helper phage with XLOLR strain , and then the pBK-CMV phagemid were digested by Xho I and EcoR I. Results The HMy2 cell line cDNA library consisting of 1.58×10 6 recombinant bacteriophages was constructed with the recombinant ratio 99.6%. The average length of the recombinant exogenous inserts was about 1.7kb.Conclusion The constructed cDNA library are deserved to screen target clones.
基金Project(41171418)supported by the National Natural Science Foundation of China
文摘To expand knowledge on microbial communities of various metal-rich levels of mine drainage environments in Anhui province, China, the archaeal and bacterial diversities were examined using a PCR-based cloning approach. Eight acid mine water samples were collected from five areas in Tongling. Phylogenetic analyses revealed that bacteria mainly fell into ten divisions, which were Betaproteobacteria, Gammaproteobacteria, Alphaproteobacteria, Deinococcus-Thermus, Nitrospira, Firmicutes, Actinobacteria, Deltaproteobacteria, Bacteroidetes, Chloroflexi. Archaea fell into three phylogenetic divisions, Thermoplasma, Ferroplasma and Thermogymnomonas. The unweighted pair group method with arithmetic mean（UPGMA） cluster analysis based on the microbial communities’ compositions revealed that five samples shared similarity with the dominance of Meiothermus and Thermomonas. Two samples had the preponderant existence of Acidithiobacillus and Leptospirillum. The remaining sample owned higher microbial communities’ diversity with the Shannon-Weaver H up to 2.91. Canonical correlation analysis（CCA） suggested that microbial community structures had great association with p H and the concentration of Hg2＋, Pb2＋, Fe3＋, Cl-, SO2- 4in water.
基金Supported by the National Natural Science Foundation of China(No.41101242)the National Basic Research Program(973 Program)of China(No.2011CB100504)the National Key Technology R&D Program of China(Nos.2011BAD11B04 and 2012BAD14B04)
文摘Taking two important agricultural soils with different pH, brown soil （Hap-Udic Luvisol） and cinnamon soil （Hap-Ustic Luvisol）, from Northeast China, a pot culture experiment with spring maize （Zea mays L.） was conducted to study the dynamic changes in the abundance and diversity of soil ammonia-oxidizing bacteria （AOB） and ammonia-oxidizing archaea （AOA） populations during maize growth period in response to the additions of nitrification inhibitors dicyandiamide （DCD） and 3,4-dimethylpyrazole phosphate （DMPP） by the methods of real-time polymerase chain reaction （PCR） assay, PCR-denaturing gradient gel electrophoresis （DGGE）, and construction of clone library targeting the amoA gene. Four treatments were established, i.e., no urea （control）, urea, urea plus DCD, and urea plus DMPP. Both DCD and DMPP inhibited growth of AOB significantly, compared to applying urea alone. Soil bacterial amoA gene copies had a significant positive linear correlation with soil nitrate content, but soil archaeal amoA gene copies did not. In both soils, all AOB sequences fell within Nitrosospira or Nitrosospira-like groups, and all AOA sequences belonged to group 1.1b crenaxchaea. With the application of DCD or DMPP, community composition of AOB and AOA in the two soils had less change except that the AOB community composition in Hap-Udic Luvisol changed at the last two growth stages of maize under the application of DCD. AOB rather than AOA likely dominated soil ammonia oxidation in these two agricultural soils.
基金supported by the"Knowledge In-novation"Program of Chinese Academy of Sciences(No.KZCX2-YW-JC407-3,KSCX2-YW-G-054-2)the Ministry of Science and Technology,China(No.2006DFA91870)
文摘The bacterial community of a bulking sludge from a municipal wastewater treatment plant with anoxic-anaerobic-oxic process was investigated by combination of cultivation and 16S rRNA gene clone library analysis for understanding the causes of bulking.A total of 28 species were obtained from 63 isolates collected from six culture media.The most cultivable species belonged to γ-Proteobacteria including Klebsiella sp.,Pseudomonas sp.,Aeromonas sp.and Acinetobacter sp.Further analysis of these strains by repetitive sequence based on polymerase chain reaction （rep-PCR） technology showed that rep-PCR yielded discriminatory banding patterns within the same genus using REP and BOX primer sets.While the culture-independent assessment revealed that β-Proteobacteria was the dominant group in the bulking sample.Sequence analysis revealed that the highest proportion （14.7%） of operational taxonomic units was 98% similar to Candidatus Accumulibacter phosphatis,which is used to remove phosphorous from wastewater.Our results indicated that combining different approaches can produce complementary information,thus generate a more accurate view of microbial community in bulking sludge.
基金supported by the National 863 Program of China(2012AA101803)the National Key Technology R&D Program of China(2012BAD14B06,2012BAD14B01)
文摘This study evaluated the microbial community dynamics and maturation time of two compost systems： biogas slurry compost and cow manure compost, with the aim of evaluating the potential utility of a biogas slurry compost system. Denaturing gradient gel electrophoresis （DGGE）, gene clone library, temperature, C/N ratio, and the germination index were employed for the investigation, cow manure compost was used as the control. Results showed that the basic strip and dominant strips of the DGGE bands for biogas slurry compost were similar to those of cow manure compost, but the brightness of the respective strips for each system were different. Shannon-Weaver indices of the two compost systems differed, possessing only 22% similarity in the primary and maturity stages of the compost process. Using bacterial 16S rRNA gene clone library analysis, 88 bacterial clones were detected. Further, 18 and 13 operational taxonomic units （OTUs） were present in biogas slurry and cow manure compost, respectively. The 18 OTUs of the biogas slurry compost belonged to nine bacterial genera, of which the dominant strains were Bacillus sp. and Carnobacterium sp.; the 13 OTUs of the cow manure compost belonged to eight bacterial genera, of which the dominant strains were Psychrobacter sp., Pseudomonas sp., and Clostridium sp. Results demonstrated that the duration of the thermophilic phase （more than 50°C） for biogas slurry compost was 8 d less than the according duration for cow manure compost, and the maturation times for biogas slurry and cow manure compost were 45 and 60 d, respectively. It is an effective biogas slurry assimilate technology by application of biogas slurry as nitrogen additives in the manufacture of organic fertilizer.
基金financially supported by the National Key Technology R & D Program of China (No.2012BAC13B04-08)the National Natural Science Foundation of China (Nos.51178451 and 51221892)
文摘Bioaerosols from wastewater treatment processes are a significant subgroup of atmospheric aerosols. In the present study,airborne microorganisms generated from a wastewater treatment station（WWTS） that uses an oxidation ditch process were diminished by ventilation.Conventional sampling and detection methods combined with cloning/sequencing techniques were applied to determine the groups,concentrations,size distributions,and species diversity of airborne microorganisms before and after ventilation. There were 3021 ± 537 CFU/m3 of airborne bacteria and 926 ± 132 CFU/m3 of airborne fungi present in the WWTS bioaerosol.Results showed that the ventilation reduced airborne microorganisms significantly compared to the air in the WWTS. Over 60% of airborne bacteria and airborne fungi could be reduced after4 hr of air exchange. The highest removal（92.1% for airborne bacteria and 89.1% for fungi） was achieved for 0.65–1.1 μm sized particles. The bioaerosol particles over 4.7 μm were also reduced effectively. Large particles tended to be lost by gravitational settling and small particles were generally carried away,which led to the relatively easy reduction of bioaerosol particles0.65–1.1 μm and over 4.7 μm in size. An obvious variation occurred in the structure of the bacterial communities when ventilation was applied to control the airborne microorganisms in enclosed spaces.
基金supported by the National Natural Science Foundation of China (No.30600082,20777089)the "Knowledge Innovation" Program of Chinese Academy of Sciences (No.kzcx1-yw-06-03)the Key Technologies R&D Program of China (No.2008BADA7B01)
文摘Fungicides have been used extensively for controlling fungal pathogens of plants. However, little is known regarding the effects that fungicides upon the indigenous bacterial communities within the plant phyllosphere. The aims of this study were to assess the impact of fungicide enostroburin upon bacterial communities in wheat phyllosphere. Culture-independent methodologies of 16S rDNA clone library and 16S rDNA directed polymerase chain reaction with denaturing gradient gel electrophoresis （PCR-DGGE） were used for monitoring the change of bacterial community. The 16S rDNA clone library and PCR-DGGE analysis both confirmed the microbial community of wheat plant phyllosphere were predominantly of the γ-Proteobacteria phyla. Results from PCR-DGGE analysis indicated a significant change in bacterial community structure within the phyllosphere following fungicide enostroburin application. Bands sequenced within control cultures were predominantly of Pseudomonas genus, but those bands sequenced in the treated samples were predominantly strains of Pantoea genus and Pseudomonas genus. Of interest was the appearance of two DGGE bands following fungicide treatment, one of which had sequence similarities （98%） to Pantoea sp. which might be a competitor of plant pathogens. This study revealed the wheat phyllosphere bacterial community composition and a shift in the bacterial community following fungicide enostroburin application.
基金supported by the Knowledge Innova-tion Program of the Chinese Academy of Sciences(No.KZCX1-YW-06-03)
文摘The response of archaeal communities to petroleum contamination in saline-alkali soil was characterized by analyses of three soil samples with different total petroleum hydrocarbon concentrations.Through the construction and screening of 16S rRNA gene clone libraries based on DNA extracts from these soils,nine distinct phylogenetic groups were identified.Statistical analyses showed that the distribution of archaeal community structures differ significantly along the gradient of petroleum contamination in these three saline- alkali soils.Five phylogenetic groups were dominant in the control soil,two of which were also abundant in the lightly contaminated soil.Four phylogenetic groups were dominant in heavily contaminated soil,one of which was also abundant in the lightly contaminated soil.The halophilic genus of Haloferax and the haloalkaliphilic genus of Natronomonas were more abundant in heavily contaminated soil.These results suggested that the genera of Haloferax and Natronomonas may have a role in the natural attenuation of petroleum- contaminated saline-alkali soil.
文摘Fungistasis is one of the important approaches to control soil-borne plant pathogens.Some hypotheses about the mechanisms for soil fungistasis had been established,which mainly focused on the soil bacterial community composition,structure,diversity as well as function.In this study,the bacterial community composition and diversity of a series of soils treated by autoclaving,which coming from the same original soil sample and showing gradient fungistasis to the target soil-borne pathogen fungi Fusarium grami...
基金Supported by the National Natural Science Foundation of China (No. 41071177)
文摘To better understand the effect of salinity on denitrification communities, soils along a salinity gradient （ranging from 7.32 to 1.70 mS cm 1） in a wetland along the Yellow Sea coastline in Jiangsu Province, China, were studied using both culture-dependent and -independent methods. Culture efforts yielded 82 isolates in total, 81.7% of which were close relatives of Bacillus sp. based on partial sequences of their 16S rRNA genes. Denaturing gradient gel electrophoresis （DGGE） analysis based on 16S rRNA sequences suggested possible existence of bacterial community succession along the salinity gradient. Clone library analysis based on nosZ gene sequences （coding nitrous oxide reductase） showed that operational taxonomic units （OTUs） associated with α-proteobacteria dominated in all three soils, whereas those associated with β- and γ-subdivisions showed a clear succession. In the high salinity soil, only the OTUs associated with a-subdivision were found. In the medium salinity soil, small proportions of β- （6.5%） and γ-associated （19.6%） OTUs were found. In the low salinity soil, the proportions were further increased to 33% and 25% for β- and γ-Proteobacteria, respectively. Statistic analysis using Unifrac P test showed that nosZ-communities in different saline soils were significantly different from each other. It could be concluded that α-subdivision of nosZ-community tended to be sustained in high salinity environments whereas β and γ-subdivisions, especially the former, tended to be sustained in low salinity environments. Salinity was the key determinant of nosZ-community composition in the environment.
基金supported by the Major Science and Technology Programs for Water Pollution Control and Management of China(No.2012ZX07205-001)the National Science and Technology Support Program(No.2008BADC4B18)
文摘The microbial community structures in an integrated two-phase anaerobic reactor（ITPAR）were investigated by 16 S r DNA clone library technology. The 75 L reactor was designed with a 25 L rotating acidogenic unit at the top and a 50 L conventional upflow methanogenic unit at the bottom, with a recirculation connected to the two units. The reactor had been operated for 21 stages to co-digest fruit/vegetable wastes and wheat straw, which showed a very good biogas production and decomposition of cellulosic materials. The results showed that many kinds of cellulose and glycan decomposition bacteria related with Bacteroidales,Clostridiales and Syntrophobacterales were dominated in the reactor, with more bacteria community diversities in the acidogenic unit. The methanogens were mostly related with Methanosaeta, Methanosarcina, Methanoculleus, Methanospirillum and Methanobacterium; the predominating genus Methanosaeta, accounting for 40.5%, 54.2%, 73.6% and 78.7% in four samples from top to bottom, indicated a major methanogenesis pathway by acetoclastic methanogenesis in the methanogenic unit. The beta diversity indexes illustrated a more similar distribution of bacterial communities than that of methanogens between acidogenic unit and methanogenic unit. The differentiation of methanogenic community composition in two phases, as well as pH values and volatile fatty acid（VFA） concentrations confirmed the phase separation of the ITPAR. Overall, the results of this study demonstrated that the special designing of ITPAR maintained a sufficient number of methanogens, more diverse communities and stronger syntrophic associations among microorganisms, which made two phase anaerobic digestion of cellulosic materials more efficient.
基金supported by the Fundamental Research Funds for the Central Universities (No. DUT09RC(3)304)the Key Laboratory of Industrial Ecology and Environmental Engineering,China Ministry of Education (No.KLIEEE-09-09)the National Natural Science Foundation of China (No. 51008045)
文摘The anaerobic ammonium oxidation （anammox） process was successfully started up from conventional activated sludge using a hybrid bioreactor within 2 months.The average removal efficiencies of ammonia and nitrite were both over 80%,and the maximum total nitrogen removal rate of 1.85 kg N/（m^3 ·day） was obtained on day 362 with the initial sludge concentration of 0.7 g mixed liquor suspended solids （MLSS）/L.Scanning electron microscope （SEM） observation of the granular sludge in the hybrid reactor clearly showed a high degree of compactness and cell sphericity,and the cell size was quite uniform.Transmission electron microscope photos showed that cells were round or oval,the cellular diameter was 0.6-1.0 μm,and the percentage of the anammoxosome compartment was 51%-85% of the whole cell volume.Fluorescence in situ hybridization analysis （FISH） indicated that anammox bacteria became the dominant population in the community （accounting for more than 51% of total bacteria on day 250）.Seven planctomycete 16S rRNA gene sequences were present in the 16S rRNA gene clone library generated from the biomass and affiliated to Candidatus Kuenenia stuttgartiensis and Candidatus Brocadia sp.,a new anammox species.In addition,the average effluent suspended solid （MLSS） concentrations of outlets I （above the non-woven carrier） and II （below the non-woven carrier） were 0.0009 and 0.0035 g/L,respectively.This showed that the non-woven carrier could catch the biomass effectively,which increased biomass and improved the nitrogen removal rate in the reactor.
基金Project (No. 20377030) supported by the National Natural ScienceFoundation of China
文摘Seashore landfill aquifers are environments of special physicochemical conditions (high organic load and high sa- linity), and microbes in leachate-polluted aquifers play a significant role for intrinsic bioremediation. In order to characterize microbial diversity and look for clues on the relationship between microbial community structure and hydrochemistry, a cul- ture-independent examination of a typical groundwater sample obtained from a seashore landfill was conducted by sequence analysis of 16S rDNA clone library. Two sets of universal 16S rDNA primers were used to amplify DNA extracted from the groundwater so that problems arising from primer efficiency and specificity could be reduced. Of 74 clones randomly selected from the libraries, 30 contained unique sequences whose analysis showed that the majority of them belonged to bacteria (95.9%), with Proteobacteria (63.5%) being the dominant division. One archaeal sequence and one eukaryotic sequence were found as well. Bacterial sequences belonging to the following phylogenic groups were identified: Bacteroidetes (20.3%), β, γ, δ and ε-subdivisions of Proteobacteria (47.3%, 9.5%, 5.4% and 1.3%, respectively), Firmicutes (1.4%), Actinobacteria (2.7%), Cyanobacteria (2.7%). The percentages of Proteobacteria and Bacteroides in seawater were greater than those in the groundwater from a non-seashore landfill, indicating a possible influence of seawater. Quite a few sequences had close relatives in marine or hypersaline environments. Many sequences showed affiliations with microbes involved in anaerobic fermentation. The remarkable abundance of sequences related to (per)chlorate-reducing bacteria (ClRB) in the groundwater was significant and worthy of further study.
基金the National NaturalScience Foundation of China (No. 39925007)the HiTech Research and Development Program (863) of China(No. 2002AA60l021)the Pilot Project of KnowledgeInnovation Program of Chinese Academy of Sciences (No.KSCX2-SW-102)
文摘The bacterial diversity of activated slud ge from submerged membrane bioreactor(SMBR)was investigated.A 16S rDNA clone library was generated,and 150 clones were screened using restriction frag ment length poly morp hism(RFLP).Of the screened clones,almost full-leng th 16S rDNA sequences of 64 clones were sequenced.Phy lo genetic tree was constructed with a database containing clone sequences from this study and bacterial rDNA sequen ces from NCBI for identification purposes.The 90.6%of the clones were affi liated with the two phy la Bacteroidetes(50%)and Proteobacteria(40%),and β-,γ-and δ-Proteobacteria acco unted for 7.8%,28.1%,and 4.7%,respectively.Minor portions were affiliated with the Actinobacteria and Firmicutes(both 3.1%).Only 6 out of 6416S rDNA sequences exhibited simil arities of more than 97%to classifed bacterial species,which indicated that a substantial fraction of the clone sequences were deri ved from unkno wn tax a.Rarefaction analysis of operational taxonomic units(OTUs)clusters demonstrated that 150 clones screened were still insuffi cient to describe the whole bacterial diversity.Measurement of water quality parameter demonstrated that performance of the SMBR maintained hig h level,and the SMBR sy stem remained stable during this study.
基金supported by the National Natural Science Foundation of China (No. 50978069)
文摘Ammonia-oxidizing archaea （AOA） are widely considered key to ammonia oxidation in various environments. However, little work has been conducted to simultaneously investigate the abundance and diversity of AOA as well as correlations between archaeal amoA genotypes and environmental parameters of different ecosystems at one district. To understand the abundance, diversity, and distribution of AOA in Pearl River Delta of China in response to various habitats, the archaeal amoA genes in soil, marine, river, lake, hot spring and wastewater treatment plant （WWTP） samples were investigated using real-time fluorescent quantitative PCR and clone libraries. Our analyses indicated that the diversity of AOA in various habitats was different and could be clustered into five major clades, i.e., estuary sediment, marine water/sediment, soil, hot spring and Cluster 1. Phylogenetic analyses revealed that the structure of AOA communities in similar ecological habitats exhibited strong relation. The canonical correspondence method indicated that the AOA community structure was strongly correlated to temperature, pH, total organic carbon, total nitrogen and dissolved oxygen variables. Assessing AOA amoA gene copy numbers, ranging from 6.84× 10^6 to 9.45 × 10^7 copies/g in dry soil/sediment, and 6.06× 10^6 to 2.41 ×10^7 copies/L in water samples, were higher than ammonia-oxidizing bacteria （AOB） by 1-2 orders of magnitude. However, AOA amoA copy numbers were much lower than AOB in WWTP activated sludge samples. Overall, these studies suggested that AOA may be a major contributor to ammonia oxidation in natural habitats but play a minor role in highly aerated activated sludge. The result also showed the ratio of AOA to AOB amoA gene abundance was positively correlated with temperature and less correlated with other environmental parameters. New data from our study provide increasing evidence for the relative abundance and diversity of ammonia-oxidizing archaea in the global nitrogen cycle.
基金supported by the Research Fund from China Priority Scientific Research Project for Water Pollution Control and Treatment (No. 2008ZX07526‐001‐004)
文摘Objective To compare the bacterioplankton communities in streams exposed to pollution of different types. Methods The bacterioplankton communities in three selected heavily polluted streams were investigated by using terminal‐restriction fragment length polymorphism （T‐RFLP） analysis in combination with 16S rRNA gene clone library analysis. Results Both T‐RFLP and 16S rRNA gene clone library revealed a great difference in bacterioplankton community composition in the different streams. Conclusion This work might provide some new insights into bioremediation of heavily polluted streams.
基金This work was supported by the National Natural Science Foundation of China(NSFC)under project contract Nos 40232021,40176037 and 30170189the Ministry of Science and Technology of China(MOST)under project contract Nos 2003AA635160,2003DF000040,G2000078500 and,2001CB409700.
文摘Phylogenetic diversity of Form I and Form II ribulose1, 5-bisphosphate carboxylase/oxygenase (RubisCO) largesubunit (rbcL) genes in the inshore and offshore areas of the East China Sea were investigated. Two new primer setswere designed for amplifying partial sequences of rbcL genes from Proteobacteria. Four rbcL gene clone libraries wereconstructed by amplification and cloning of approximately 640~800 bp sequences of bacterioplankton populations.The method of screening library by denaturing gradient gel electrophoresis (DGGE) was introduced. The resultsshow that the diversity of Form I is higher in offshore waters with higher salinity and lower productivity, while thatof Form II is higher at the inshore station where salinity is lower and productivity is higher. Several clusters ofsequences obtained are deeply rooted and show low similarity (60%~78%) to the known rbcL in existing databases.The degree of diversity of rbcL genes is directly related to environmental variables, including temperature, salinity,pH, dissolved oxygen, etc. These results indicate that rbcL gene can be used as an effective indicator for geneticdiversity and population variability of bacterioplankton with the ability of carbon dioxide fixation in the sea.
基金supported by the National Natural Science Foundation of China (Nos.41476150 and 41276179)Guangdong Natural Science Foundation (No.S2011030005257)the Science and Technology Project of Guangdong Province (Nos.2012A031100009 and 2012B060400016)
文摘Micro-communities are supposed to have more potential functions of biodegradation of polysaccharides than single strain; however, the intestinal mi ties involved in the biodegradation of Enteromorpha polysaccharides （EP） were sel- dom reported. In order to obtain the EP-degrading micro-community, the intestines of Siganus oramin was obtained to isolate the micro-communities, which were enriched by 0.3% of EP as the sole carbon source. A stable micro-community with EP degradative capability was achieved after seven generations of subculture, named H1. Results showed that H1 was able to degrade 75% of EP within 24 hours, and the activity of EP lyases reached 500 U mL-1 in 32 hours. With denaturing gradient gel electrophoresis （DGGE） and 16S rRNA gene clone library analysis, ten bacteria closely related to Marinomonas pontica, Microbacterium sp., Leucobacter chironomi, Cyclobacterium sp., Algoriphagus winogradskyi, Pseudoalteromonas sp. and Vibrio sp. were determined. Furthermore, compared with the DGGE bands sequence and the clone library analysis, the dominant bacteria of the EP-biodegrading mi- cro-community were Pseudoalteromonas sp. and Vibrio sp., with the respective proportion of 38% and 46%, and they should play an important role in EP degradation together with other degrading bacteria in the micro-community H1.
