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1.
Microbes Environ ; 35(1)2020.
Artigo em Inglês | MEDLINE | ID: mdl-31969532

RESUMO

The pmoA gene, encoding particulate methane monooxygenase in methanotrophs, and nirS and nirK genes, encoding bacterial nitrite reductases, were examined in the root and rhizosphere sediment of three common emergent macrophytes (Phragmites australis, Typha angustifolia, and Scirpus triqueter) and unvegetated sediment from eutrophic Wuliangsuhai Lake in China. Sequencing analyses indicated that 334 out of 351 cloned pmoA sequences were phylogenetically the most closely related to type I methanotrophs (Gammaproteobacteria), and Methylomonas denitrificans-like organisms accounted for 44.4% of the total community. In addition, 244 out of 250 cloned nirS gene sequences belonged to type I methanotrophs, and 31.2% of nirS genes were the most closely related to paddy rice soil clone SP-2-12 in Methylomonas of the total community. Three genera of type I methanotrophs, Methylomonas, Methylobacter, and Methylovulum, were common in both pmoA and nirS clone libraries in each sample. A quantitative PCR (qPCR) analysis demonstrated that the copy numbers of the nirS and nirK genes were significantly higher in rhizosphere sediments than in unvegetated sediments in P. australis and T. angustifolia plants. In the same sample, the nirS gene copy number was significantly higher than that of nirK. Furthermore, type I methanotrophs were localized in the root tissues according to catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH). Thus, nirS-carrying type I methanotrophs were enriched in macrophyte root and rhizosphere sediment and are expected to play important roles in carbon/nitrogen cycles in a eutrophic wetland.


Assuntos
Eutrofização , Gammaproteobacteria/genética , Genes Bacterianos/genética , Magnoliopsida/microbiologia , Microbiologia do Solo , Áreas Alagadas , Proteínas de Bactérias/genética , China , Gammaproteobacteria/classificação , Gammaproteobacteria/metabolismo , Dosagem de Genes , Lagos/microbiologia , Metano/metabolismo , Nitrito Redutases/genética , Oxigenases/genética , Raízes de Plantas/microbiologia , Rizosfera
2.
Sci Total Environ ; 701: 134601, 2020 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-31734485

RESUMO

Glyphosate-based herbicides are the most commonly used herbicide worldwide. Although glyphosate is known to be toxic to aquatic organisms, it can also have stimulatory effects on small-size (ø <2 µm) cyanobacteria (Pcy) able to metabolize and degrade glyphosate and AMPA. Several previous experimental studies in micro- and mesocosms reported increases of Pcy abundance in response to glyphosate additions, but comparable field evidence is presently unavailable. We surveyed a large geographical area in order to collect information on Pcy abundance from lakes within the Pampa region (with over three decades of glyphosate usage) and lakes from Patagonia (with virtually no history of glyphosate usage). Fifty-two Pampean lakes and 24 Patagonian lakes were surveyed. We used three indicators of glyphosate impact: herbicide concentration, the presence of phosphonate metabolism genes (responsible for glyphosate and AMPA degradation) in environmental DNA samples, and descriptors of land use in the surrounding area of each lake. We addressed three questions: (1) is there field evidence of stimulatory effects of glyphosate on picocyanobacteria abundance? (2) is the magnitude of the effects of glyphosate in natural systems comparable to that reported under controlled experimental conditions? and (3), how do the effects of glyphosate compare to the effects of other potential environmental drivers of Pcy biomass? The collected evidence is consistent with the hypothesis that long-term agricultural practices relying on glyphosate-based technologies had important effects on freshwater microbial communities, particularly by promoting increases in picocyanobacteria abundance.


Assuntos
Cianobactérias/fisiologia , Monitoramento Ambiental , Glicina/análogos & derivados , Herbicidas , Lagos/microbiologia , Agricultura , Poluentes Químicos da Água
3.
Chemosphere ; 239: 124796, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31520972

RESUMO

In July 2013, a fatal train derailment led to an explosion and fire in the town of Lac-Mégantic (LM), Quebec, and the crude oil contamination of regional surface water, soil, and sediment in the adjacent Lake Mégantic. This study investigated the degradation potential of the spilled crude oil by using the sediments from the incident site as the source of microorganisms. Two light crude oils (LM source oil and Alberta Sweet Mixed Blend (ASMB)) were tested at 22 °C for 4 weeks and 4 °C for 8 weeks, respectively. The post-incubation biological and chemical information of the samples were analysed. There was no marked difference in degradation efficacy and biological activities for both the LM and ASMB oils, although the biodegradation potential differed between the two incubations. Higher temperature favoured the growth of microorganisms, thus for the degradation of all petroleum hydrocarbons, except for some conservative biomarkers. The degradation of both oils followed the order of resolved components > total saturated hydrocarbons (TSH) > unresolved complex mixture (UCM) >total aromatic hydrocarbons (TAH). Normal alkanes were generally degraded more significantly than branched ones, and polycyclic aromatic hydrocarbons (PAHs). Degradation of polycyclic aromatic hydrocarbons (PAHs) and their alkylated congeners (APAHs) for both incubations generally decreased as the number of aromatic rings, and the degree of alkylation increased. This study showed that the LM sediments can biodegrade the petroleum hydrocarbons efficaciously if appropriate ambient temperatures are generated to favour the growth of autochthonous microorganisms.


Assuntos
Sedimentos Geológicos/microbiologia , Hidrocarbonetos/química , Hidrocarbonetos/metabolismo , Petróleo/metabolismo , Poluentes Químicos da Água/metabolismo , Alcanos/química , Alcanos/metabolismo , Biodegradação Ambiental , Lagos/microbiologia , Poluição por Petróleo , Hidrocarbonetos Policíclicos Aromáticos/química , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Quebeque , Temperatura Ambiente , Poluentes Químicos da Água/química
4.
Sci Total Environ ; 702: 134803, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31731125

RESUMO

Photosynthetic picoeukaryotes (PPEs) are key players in aquatic systems, while their diversity and community composition dynamics remain poorly understood. The monthly composition of PPEs in Lake Chaohu was investigated using a combination of flow cytometry sorting and high throughput sequencing. Results indicated that temperature is the most important factor shaping PPEs community structure. The PPEs community can be categorized into three groups that are dominant at different temperature ranges: high temperature (>21.8 °C), intermediate temperature (between 9.8 °C and 21.8 °C) and low temperature (<9.8 °C). At the supergroup level, Cryptophyta were dominant at the intermediate temperature level, and Bacillariophyta were prevalent at low temperatures. In comparison, Chlorophyta PPEs were sensitive to temperature at the order level. Molecular network analysis using 18S rDNA sequencing results from sorted samples revealed that the Operational Taxonomic Units (OTUs) of PPE from the same taxonomic groups were predominantly positive, implying that they were occupying similar niches. The cooccurrence patterns between PPEs and fungi were mostly negative. In particular, OTU101, which was associated with Chytridiomycota, was negatively related to many OTUs belonging to Chlorophyta and Diatom, indicating that their potential parasitic associations may be not species-specific.


Assuntos
Lagos/microbiologia , Temperatura Ambiente , Microbiologia da Água , Clorófitas , Monitoramento Ambiental , Haptófitas , Fotossíntese
5.
Huan Jing Ke Xue ; 40(7): 3285-3294, 2019 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854730

RESUMO

Human activities and climate change cause the degradation of subalpine lake ecosystems, which induce the shift of microbial community structure. The spatio-temporal dynamics and the diversity maintenance mechanisms of bacterial communities in Gonghai Lake in Ningwu, Shanxi, were investigated by using Q-PCR and DGGE. The results showed that the temperature), pH, dissolved oxygen, electrical conductivity salinity, and ammonium nitrogen (NH4+) contestation were significantly different among the different sampling depths during different months. Bacterial abundance was the highest in August and the lowest in November, and the abundance was higher in the middle water layer (2 m, 4 m, and 6 m depths), but relatively low in the surface layer and bottom layer (0 m and 8 m depths, respectively). The α diversity index of bacterial communities had significant differences among the different months and depths, and showed an initial decreasing trend and then an increasing trend from April to December. A PERMANOVA test showed that the spatial distribution of bacterial communities was significantly different among depths (P<0.001). The results of redundancy analysis and variation partitioning indicated that environmental selection and diffusion limitation had an effect on the maintenance of the diversity patterns of bacterial communities at the different depths of GH. However, the relative effect of environmental factors was stronger, of which the concentration of NO3-, NO2-, and NH4+ were the main influencing factors. In conclusion, the bacterial communities in GH subalpine lake showed clear spatio-temporal distribution patterns, and environmental variables had a significant effect on shaping the community diversity.


Assuntos
Bactérias/classificação , Lagos/microbiologia , Microbiota , Biodiversidade , China , Concentração de Íons de Hidrogênio , Nitrogênio , Oxigênio , Salinidade , Estações do Ano , Análise Espaço-Temporal , Temperatura Ambiente
6.
Int J Syst Evol Microbiol ; 69(12): 3728-3739, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31693471

RESUMO

The Arxan-Chaihe volcanic field of the Da Hinggan mountains in north-East PR China hosts various typical crater lakes. In this study we performed a yeast diversity survey using water sampled from five crater lakes and a total of 122 yeast strains belonging to 33 species of 25 genera were isolated. Three strains, TFL1-L, TFL2B and ATC4C, were identified as three novel species belonging to the Tremellomycetes based on a multiple gene phylogeny and on the comparison of physiological data. A phylogenetic study employing the sequences of seven genes indicated that the new species were more related to three separated phylogenetic lineages of the Tremellomycetes and their closest relatives were Heterocephalacria arrabidensis, Phaeotremella skinneri and Solicoccozyma keelungensis. The divergence values of the D1/D2 domain of LSU sequences of strains TFL1-L, TFL2B and ATC4C from H. arrabidensis CBS 8678T, P. skinneri CBS 5029T and S. keelungensisSN-82T were 4.8,3.4,2.1 %, respectively. The divergence values of the sequences of ITS regions between strains TFL1-L, TFL2B and ATC4C and their close relatives (H. arrabidensis, P. skinneri and S. keelungensis) were 16.1, 5.9 and 8.1  %, respectively. Moreover, the three strains differed from their phylogenetic neighbours by the ability to grow on distinct carbon and nitrogen sources. On the basis of these findings, it is suggested that these strains represent three novel species for which the names Heterocephalacria sinensis sp. nov. (holotype CGMCC 2.5595), Phaeotremella lacus sp. nov. (holotype CGMCC 2.5580) and Solicoccozyma aquatica sp. nov. (holotype CGMCC 2.5574) are proposed.


Assuntos
Basidiomycota/classificação , Lagos/microbiologia , Filogenia , Basidiomycota/isolamento & purificação , China , DNA Fúngico/genética , DNA Espaçador Ribossômico/genética , Técnicas de Tipagem Micológica , Análise de Sequência de DNA
7.
Syst Appl Microbiol ; 42(6): 126016, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31635887

RESUMO

Hypoxic and anoxic niches of meromictic lakes are important sites for studying the microbial ecology of conditions resembling ancient Earth. The expansion and increasing global distribution of such environments also means that information about them serves to understand future phenomena. In this study, a long-term chemical dataset (1996-2015) was explored together with seasonal (in 2015) information on the diversity and abundance of bacterial and archaeal communities residing in the chemocline, monimolimnion and surface sediment of the marine meromictic Rogoznica Lake. The results of quantitative PCR assays, and high-throughput sequencing, targeting 16S rRNA genes and transcripts, revealed a clear vertical structure of the microbial community with Gammaproteobacteria (Halochromatium) and cyanobacteria (Synechococcus spp.) dominating the chemocline, Deltaproteobacteria and Bacteroidetes dominating the monimolimnion, and significantly more abundant archaeal populations in the surface sediment, most of which affiliated to Nanoarchaeota. Seasonal changes in the community structure and abundance were not pronounced. Diversity in Rogoznica Lake was found to be high, presumably as a consequence of stable environmental conditions accompanied by high dissolved carbon and nutrient concentrations. Long-term data indicated that Rogoznica Lake exhibited climate changes that could alter its physico-chemical features and, consequently, induce structural and physiological changes within its microbial community.


Assuntos
Biodiversidade , Lagos/microbiologia , Microbiota , Oxigênio/metabolismo , Archaea/classificação , Archaea/genética , Archaea/isolamento & purificação , Archaea/metabolismo , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Mudança Climática , Bases de Dados de Compostos Químicos , Irlanda , Lagos/química , Microbiota/genética , Oxigênio/análise , RNA Ribossômico 16S/genética , Estações do Ano , Microbiologia da Água
8.
J Water Health ; 17(5): 826-836, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31638032

RESUMO

There is a global concern regarding the occurrences of harmful algal blooms (HABs) and their effects on human health. Lake Victoria (LV) has been reported to face eutrophication challenges, resulting in an increase of bloom-forming cyanobacteria. This study is aimed at understanding the association of HABs and health risks at Ukerewe Island. A cross-sectional study conducted on 432 study subjects and water samples for cyanobacteria species identification were collected at LV shores. The results reveal that concentrations of cyanobacteria cells are beyond (WHO) acceptable limits; species of Microcystis aeruginosa range from 90,361.63 to 3,032.031.65 cells/mL and Anabaena spp. range from 13,310.00 to 4,814,702 cells/mL. Water usage indicates that 31% use lake water, 53% well water and 16% treated supplied pipe water. Vomiting and throat irritation was highly reported by lake water users as compared to wells and pipe water (P < 0.001). Gastrointestinal illness (GI) was significantly elevated among lake water users as compared to pipe and well water users (P < 0.001). Visible blooms in lake water were associated with GI, skin irritation and vomiting as compared to water without visible blooms (P < 0.001). The concentration of cyanobacteria blooms poses greater risks when water is used without treatment.


Assuntos
Proliferação Nociva de Algas , Lagos/microbiologia , Microcystis , Estudos Transversais , Humanos , Tanzânia
9.
Int J Syst Evol Microbiol ; 69(7): 2108-2113, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31663498

RESUMO

Strain M8-2T, which was isolated from brackish lake water (Lake Sanaru) in Japan, was characterized for representation of a novel species in the genus Algoriphagus. Cells of strain M8-2T were aerobic, Gram-stain-negative and curved-rod-shaped (0.2-0.5 µm wide and 0.7-1.9 µm long). Strain M8-2T grew optimally at 30 °C, pH 6.5-7.5 and in the presence of 0.5-1.0 % (w/v) NaCl. MK-7 was the sole isoprenoid quinone. The major polar lipids were phosphatidylethanolamine, an unidentified phospholipid and an unidentified polar lipid. The predominant cellular fatty acids were iso-C15 : 0 and anteiso-C15 : 0. Phylogenetic analysis based on its 16S rRNA gene sequence showed that strain M8-2T belonged to the genus Algoriphagus and was closely related to Algoriphagus aquatilis A8-7T, Algoriphagus boseongensis BS-R1T, Algoriphagus aquaeductus T4T, Algoriphagus olei CC-Hsuan-617T, Algoriphagusshivajiensis NIO-S3T and Algoriphagus mannitolivorans DSM 15301T with sequence similarities of 96.6-97.4 %. Results of average nucleotide identity (<75 %) and digital DNA-DNA hybridization (<19 %) studies showed that M8-2T was distinct from its phylogenetic relatives. Based on the results of tests for acid production, the predominant cellular fatty acid composition, the DNA G+C content and phylogenetic position, a novel species in the genus Algoriphagus, with the name Algoriphagussanaruensis sp. nov., is proposed for strain M8-2T (=JCM 31446T=LMG 29969T).


Assuntos
Bacteroidetes/classificação , Lagos/microbiologia , Filogenia , Técnicas de Tipagem Bacteriana , Bacteroidetes/isolamento & purificação , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Japão , Hibridização de Ácido Nucleico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
10.
J Basic Microbiol ; 59(12): 1173-1184, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31621083

RESUMO

Lipids are hydrocarbons comprised of long-chain fatty acids and are found in all living things. In the environment, microorganisms degrade them to obtain energy using esterases and lipases. These enzymes are nowadays used in different industrial applications. We report isolation of 24 bacteria with esteresic and lipolytic activity from Lake Magadi, Kenya. The isolates were characterised using morphological, biochemical, and molecular methods. Isolates grew at an optimum salt concentration of 5-8% (w/v), pH range of 8.0-9.0, and temperature range of 35-40°C. The isolates were positive for esterase and lipase assay as well as other extracellular enzymes. Phylogenetic analysis of the 16S ribosomal RNA gene showed that the isolates were affiliated to the genus Bacillus, Alkalibacterium, Staphylococcus, Micrococcus, Halomonas, and Alkalilimnicola. None of the bacterial isolates produced antimicrobial agents, and all of them were resistant to trimethoprim and nalidixic acid but susceptible to streptomycin, amoxillin, chloramphenicol, and cefotaxime. Growth at elevated pH, salt, and temperature is an indicator that the enzymes from these organisms could function well under haloalkaline conditions. Therefore, Lake Magadi could be a good source of isolates with the potential to produce unique biocatalysts for the biotechnology industry.


Assuntos
Bactérias/classificação , Bactérias/enzimologia , Biodiversidade , Esterases/metabolismo , Lagos/microbiologia , Lipase/metabolismo , Microbiologia da Água , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Bactérias/genética , DNA Bacteriano/genética , Esterases/genética , Concentração de Íons de Hidrogênio , Quênia , Lagos/química , Lipase/genética , Testes de Sensibilidade Microbiana , Filogenia , RNA Ribossômico 16S/genética , Tolerância ao Sal , Análise de Sequência de DNA , Temperatura Ambiente
11.
Ecotoxicol Environ Saf ; 184: 109634, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31520950

RESUMO

Imidazolium-based ionic liquids (IL) with short-alkyl side chain such as 1-ethyl-3-methyl-imidazolium chloride ([Emim]Cl) and 1-butyl-3-methyl-imidazolium chloride ([Bmim]Cl) has immense application potential including in lignocellulosic bioenergy production. But they are toxic to most microorganisms, and those isolated from different environments as IL-tolerant have salt tolerance capabilities. This study evaluates the relationship between salt and [Emim]Cl tolerance of microorganisms using different salinity sediments (2-19%) and brines (35%) of India's largest inland hypersaline lake, Sambhar in Rajasthan as the model system. While samples with 2% and 35% salinities do not yield any [Emim]Cl (100 mM) tolerant colonies, others have 6-50% colonies tolerant to the IL. Similar trend was observed with 50 mM [Bmim]Cl. Moderate halophilic isolates of genera Halomonas and Bacillus (growth in 0.7-3.0 M NaCl) isolated from the sediments could grow in as high as 375 mM [Emim]Cl, or 125 mM [Bmim]Cl facilitated by higher synthesis, and uptake of organic osmolytes; and up to 1.7-fold increased activity of active efflux pumps. [Bmim]Cl was more toxic than [Emim]Cl in all performed experiments. [Emim]Cl-adapted cells could trounce IL-induced stress. Interestingly, enrichment with 100 mM [Emim]Cl resulted in increase of IL-tolerant colonies in all sediments including the one with 2% salinity. However, the salt saturated brines (35%) do not yield any such colony even after repeated incubations. Extreme halophilic archaea, Natronomonas (growth in 3.0-4.0 M NaCl) isolated from such brines, were exceedingly sensitive to even 5 mM [Emim]Cl, or 1 mM [Bmim]Cl. Two additional extremophilic archaea, namely Haloferax and Haladaptatus were also sensitive to the tested ILs. Archaeal sensitivity is possibly due to the competitive interaction of [Emim]+ with their acidic proteome (15.4-17.5% aspartic and glutamic acids, against 10.7-12.9% in bacteria) that they maintain to stabilize the high amount of K+ ion accumulated by salt-in strategy. Thus, general salt adaptation strategies of moderate halophilic bacteria help them to restrain toxicity of these ILs, but extremophilic archaea are highly sensitive and demands meticulous use of these solvents to prevent environmental contamination.


Assuntos
Halobacteriaceae/efeitos dos fármacos , Halomonas/efeitos dos fármacos , Imidazóis/toxicidade , Líquidos Iônicos/toxicidade , Sedimentos Geológicos/química , Sedimentos Geológicos/microbiologia , Índia , Lagos/química , Lagos/microbiologia , Salinidade , Tolerância ao Sal
12.
Curr Microbiol ; 76(12): 1537-1544, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31555854

RESUMO

One novel ascomycetous yeast strain TF5-16-2 was isolated from water samples of Tuofengling crater lake located in Da Hinggan Ling Mountain, in the Inner Mongolia province of China. Morphological, physiological characteristics, as well as phylogenetic analyses of D1/D2 domains of the large subunit rRNA (LSU), ITS region, small subunit rRNA (SSU), and elongation factor-1α (EF-1α) were performed and finally confirmed the phylogenetic placement of strain TF5-16-2 in the genus Wickerhamomyces. Sequences analysis revealed that strain TF5-16-2 differed from its most closely related phylogenetic neighbors 'Candida' silvicultrix CBS 6269T and Wickerhamomyces anomalus CBS 5759T by 8.0% (including 2.3% gaps), 8.5% (including 2.4% gaps) divergences in D1/D2 domains of LSU, and 11% (including 4.3% gaps) and 13% (including 4.4% gaps) divergences in ITS region, respectively. As the considerable sequence divergence and distinguishable physiological characteristics, strain TF5-16-2 was proposed as a new species of the genus Wickerhamomyces, with the name Wickerhamomyces kurtzmanii sp. nov. (holotype = CGMCC 2.5597, Mycobank number is MB829959).


Assuntos
Lagos/microbiologia , Saccharomycetales/isolamento & purificação , China , DNA Fúngico/genética , DNA Espaçador Ribossômico/genética , Proteínas Fúngicas/genética , Técnicas de Tipagem Micológica , Fator 1 de Elongação de Peptídeos/genética , Filogenia , Saccharomycetales/classificação , Saccharomycetales/genética
13.
Artigo em Inglês | MEDLINE | ID: mdl-31547457

RESUMO

Currently, water contaminated with fecal matter poses a threat to public health and safety. Thus, enteric viruses are tested for as a part of water quality indicator assays; however, enteric viruses have not yet been listed in the criteria. Effective and sensitive methods for detecting enteric viruses are required in order to increase water safety. This study utilized enteric viruses as possible alternative indicators of water quality to examine fresh water in six sites in Poyang Lake, Nanchang, Jiangxi Province. The presence of norovirus geno-groups II (NoV GII), enteroviruses (EoV) and adenoviruses (AdV) were determined using Tianjin's protocol and Hawaii's protocol during a six month period from 2016-2017. The former used an electropositive material method for viral concentration and Taqman-q reverse transcription polymerase chain reaction (RT-PCR) to detect enteric viruses; while the latter used a filtration-based method for viral concentration and RT-PCR for enteric virus detection. There is a statistically significant difference between Tianjin's method and Hawaii's method for the detection of enteric viruses, such as NoV GII, EoV, and AdV (n = 36, p < 0.001). The enteric viruses showed no significant positive correlation with bacteria indicators (n = 36, p > 0.05). These data stress the need for additional indicators when establishing water quality systems, and the possibility of using enteric viruses as water quality indicators. It has become essential to improve shortcomings in order to search for an adequate method to detect enteric viruses in water and to implement such method in water quality monitoring.


Assuntos
Bactérias/isolamento & purificação , Enterovirus/isolamento & purificação , Lagos/microbiologia , Norovirus/isolamento & purificação , Microbiologia da Água , Bactérias/genética , China , Enterovirus/genética , Fezes/microbiologia , Humanos , Norovirus/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Qualidade da Água/normas
14.
Nat Commun ; 10(1): 4230, 2019 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-31530813

RESUMO

In alkaline soda lakes, concentrated dissolved carbonates establish productive phototrophic microbial mats. Here we show how microbial phototrophs and autotrophs contribute to this exceptional productivity. Amplicon and shotgun DNA sequencing data of microbial mats from four Canadian soda lakes indicate the presence of > 2,000 species of Bacteria and Eukaryotes. We recover metagenome-assembled-genomes for a core microbiome of < 100 abundant bacteria, present in all four lakes. Most of these are related to microbes previously detected in sediments of Asian alkaline lakes, showing that common selection principles drive community assembly from a globally distributed reservoir of alkaliphile biodiversity. Detection of > 7,000 proteins show how phototrophic populations allocate resources to specific processes and occupy complementary niches. Carbon fixation proceeds by the Calvin-Benson-Bassham cycle, in Cyanobacteria, Gammaproteobacteria, and, surprisingly, Gemmatimonadetes. Our study provides insight into soda lake ecology, as well as a template to guide efforts to engineer biotechnology for carbon dioxide conversion.


Assuntos
Bactérias/isolamento & purificação , Lagos/microbiologia , Microbiota , Filogenia , Álcalis/análise , Processos Autotróficos , Bactérias/classificação , Bactérias/genética , Bactérias/efeitos da radiação , Biodiversidade , Canadá , Ciclo do Carbono , Lagos/química , Luz , Processos Fototróficos , Enxofre/metabolismo
15.
Artigo em Inglês | MEDLINE | ID: mdl-31510040

RESUMO

Extracellular DNA (exDNA) pool in aquatic environments is a valuable source for biomonitoring and bioassessment. However, degradation under particular environmental conditions can hamper exDNA detectability over time. In this study, we analyzed how different biotic and abiotic factors affect the degradation rate of extracellular environmental DNA using 16S rDNA sequences extracted from the sediment of a eutrophic lake and Anabaena variabilis cultured in the laboratory. We exposed the extracted exDNA to different levels of temperature, light, pH, and bacterial activity, and quantitatively analyzed the concentration of exDNA during 4 days. The solution containing bacteria for microbial activity treatment was obtained from the lake sediment using four consecutive steps of filtration; two mesh filters (100 µm and 60 µm mesh) and two glass fiber filters (2.7 µm and 1.2 µm pore-sized). We found that temperature individually and in combination with bacterial abundance had significant positive effects on the degradation of exDNA. The highest degradation rate was observed in samples exposed to high microbial activity, where exDNA was completely degraded within 1 day at a rate of 3.27 day-1. Light intensity and pH had no significant effects on degradation rate of exDNA. Our results indicate that degradation of exDNA in freshwater ecosystems is driven by the combination of both biotic and abiotic factors and it may occur very fast under particular conditions.


Assuntos
DNA Ribossômico/análise , Lagos/microbiologia , Anabaena variabilis/metabolismo , Biodegradação Ambiental , DNA Ribossômico/química , DNA Ribossômico/efeitos da radiação , Eutrofização , Sedimentos Geológicos/microbiologia , Concentração de Íons de Hidrogênio , Luz , Temperatura Ambiente , Microbiologia da Água
16.
J Basic Microbiol ; 59(11): 1112-1124, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31502316

RESUMO

Microcystis aeruginosa blooms are a worldwide serious environmental problem and bloom control with bacteria is promising. In this study, a Bacillus licheniformis strain Sp34 with potent algicidal and inhibitory effects on the microcystins synthesis against fast-growing M. aeruginosa was isolated from Dianchi Lake. Sp34 killed the bloom-causing algal strain M. aeruginosa DCM4 of Dianchi Lake with an initial Chlorophyll-a concentration of 2.0 mg/L at a cell density of no less than 1.35 × 105 CFU/ml. It can also efficiently kill some other harmful algal species, such as M. wesenbergii and Phormidium sp. The algicidal activity of Sp34 relied on the release of algicidal substances, which had good heat (-20°C to 121°C) and acid-base (pH 3-11) resistance. In addition, the high algicidal activity depended on the good growth of algae indicated by the significantly positive correlations between algal growth and algicidal ratio (p < .001). The algicidal effect of Sp34 involved causing oxidative stress, lipid peroxidation, and morphological injury of algal cells, along with DNA damage and dysfunction of DNA-repair function, weakening the photosynthesis system, and inhibiting microcystin synthesis. In general, Sp34 can kill fast-growing M. aeruginosa and inhibit algal microcystin synthesis efficiently, so, it is a promising biocontrol agent to mitigate cyanobacterial blooms.


Assuntos
Bacillus licheniformis/metabolismo , Agentes de Controle Biológico/metabolismo , Agentes de Controle Biológico/farmacologia , Microcystis/efeitos dos fármacos , Antibiose , Bacillus licheniformis/classificação , Bacillus licheniformis/genética , Bacillus licheniformis/crescimento & desenvolvimento , Clorofila/análogos & derivados , Clorofila/biossíntese , Clorofila/genética , Eutrofização/efeitos dos fármacos , Lagos/microbiologia , Microcistinas/biossíntese , Microcistinas/genética , Microcystis/genética , Microcystis/crescimento & desenvolvimento , Microcystis/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Transcrição Genética/efeitos dos fármacos
17.
Environ Pollut ; 254(Pt B): 113108, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31491696

RESUMO

Taihu Lake is one of the largest freshwater lakes in China and serves as an important source for drinking water. This lake is suffering from eutrophication, cyanobacterial blooms and fecal pollution, and the inflow Tiaoxi River is one of the main contributors. The goal here was to characterize the bacterial community structure of Tiaoxi River water by next-generation sequencing (NGS), paying attention to bacteria that are either fecal-associated or pathogenic, and to examine the relationship between environmental parameters and bacterial community structure. Water samples collected from 15 locations in three seasons, and fecal samples collected from different hosts and wastewater samples were used for bacterial community analysis. The phyla Proteobacteria, Actinobacteria, Bacteroidetes, and Cyanobacteria were predominant in most of the water samples tested. In fecal samples, Bacteroidetes, Firmicutes, and Proteobacteria were abundant, while wastewater samples were dominated by Proteobacteria, Bacteroidetes, Acidobacteria, and Chloroflexi. The cluster analysis and principal coordinate analysis indicated that bacterial community structure was significantly different between water, fecal and sewage samples. Shared OTUs between water samples and chicken, pig, and human fecal samples ranged from 4.5 to 9.8% indicating the presence of avian, pig and human fecal contamination in Tiaoxi River. At genus level, five bacterial genera of fecal origin and sequences of seven potential pathogens were detected in many locations and their presence was correlated well with the land use pattern. The sequencing data revealed that Faecalibacterium could be a potential target for human-associated microbial source-tracking qPCR assays. Our results suggest that pH, conductivity, and temperature were the main environmental factors in shaping the bacterial community based on redundancy analysis. Overall, NGS is a valuable tool for preliminary investigation of environmental samples to identify the potential human health risk, providing specific information about fecal and potentially pathogenic bacteria that can be followed up by specific methods.


Assuntos
Bactérias/isolamento & purificação , Fezes , Sequenciamento de Nucleotídeos em Larga Escala , Lagos/microbiologia , Rios/microbiologia , Poluição da Água , Animais , Bactérias/classificação , Bacteroidetes/isolamento & purificação , China , Cianobactérias/isolamento & purificação , Eutrofização , Fezes/microbiologia , Humanos , Microbiota , Tipagem Molecular , Proteobactérias/isolamento & purificação , RNA Bacteriano , Estações do Ano
18.
Int J Syst Evol Microbiol ; 69(11): 3420-3425, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31385782

RESUMO

A novel Gram-stain-negative, aerobic, non-motile and rod-shaped bacterium was isolated from Lake Dajiaco on the Tibetan Plateau. Strain DJCT grew without NaCl and tolerated up to 3 % (w/v) NaCl. Growth occurred at pH 6.0-10.0 (optimum, pH 7.0-8.0) and 15-37 °C (optimum, 25-30 °C). Vitamins were not required for growth. The main polar lipids of strain DJCT were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The predominant respiratory quinone was Q-10. The major fatty acid was C18 : 1ω7c. Genome sequencing revealed a genome size of 4.61 Mbp and a G+C content of 62.9 mol%. Analysis of 16S rRNA sequences showed that strain DJCT belonged to the genus Tabrizicola, with the closest neighbour Tabrizicola aquatica RCRI19T (97.5 %). DNA-DNA relatedness between strain DJCT and the closest phylogenetically related strain T. aquatica RCRI19T was 40.8 %. Stain DJCT was clearly distinguished from the type strain mentioned above through phylogenetic analysis, DNA-DNA hybridization, fatty acid composition data and a range of physiological and biochemical characteristic comparisons. Based on its phenotypic and chemotaxonomic characteristics, strain DJCT could be classified as a representative of a novel species of the genus for which the name Tabrizicola alkalilacus sp. nov. is proposed. The type strain is DJCT (=CICC 24242T=KCTC 62173T).


Assuntos
Lagos/microbiologia , Filogenia , Rhodobacteraceae/classificação , Álcalis , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Concentração de Íons de Hidrogênio , Hibridização de Ácido Nucleico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Rhodobacteraceae/isolamento & purificação , Análise de Sequência de DNA , Tibet , Ubiquinona/análogos & derivados , Ubiquinona/química
19.
Int J Syst Evol Microbiol ; 69(11): 3581-3585, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31429814

RESUMO

A novel marine Gram-stain-negative, non-motile, aerobic and rod-shaped bacterium, designated strain DSL-48T, was isolated from tidal flat sediment sampled from the East China Sea and characterized phylogenetically and phenotypically. Bacterial optimal growth occurred at 35 °C (range, 4-37 °C), pH 6 (pH 5-10) and with 4 % (w/v) NaCl (0-7 %). The nearest phylogenetic neighbour was Confluentibacter citreus KCTC 52638T with 16S rRNA gene similarity of 97.1 %. The predominant respiratory quinone was menaquinone-6 (MK-6). The major polar lipids were phosphatidylethanolamine, three unidentified aminolipids and four unidentified lipids. The major fatty acids of strain DSL-48T were iso-C15 : 0, iso-C17 : 0 3-OH, anteiso-C15 : 0, iso-C15 : 0 3-OH and iso-C16 : 0 3-OH. The G+C content of the genomic DNA was 33.3 mol%. The combined genotypic and phenotypic data indicated that strain DSL-48T represents a novel species of the genus Confluentibacter, for which the name Confluentibacter sediminis sp. nov. is proposed, with the type strain DSL-48T (=KCTC 62648T=MCCC 1K03537T).


Assuntos
Flavobacteriaceae/classificação , Sedimentos Geológicos/microbiologia , Filogenia , Microbiologia da Água , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Flavobacteriaceae/isolamento & purificação , Lagos/microbiologia , Lipídeos/química , Oceanos e Mares , RNA Ribossômico 16S/genética , Águas Salinas , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
20.
Sci Total Environ ; 695: 133785, 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31421332

RESUMO

Polybrominated diphenyl ethers (PBDEs) are typical persistent organic pollutants (POPs) in the environment. However, little is known about their effects on phosphorus mineralizing bacteria (PMB) in eutrophic lake sediments, despite the critical role of PMB in phosphorus (P) biogeochemical cycling. In this study, we carried out a 60-day microcosm experiment to understand the effects of 2 and 20 mg kg-1 dry weight decabromodiphenyl ether (BDE-209) on the activity, abundance, diversity, and community composition of PMB in the sediment of Taihu Lake, a typical eutrophic lake in China. The results showed that BDE-209 contamination, regardless of the contamination levels, significantly increased the orthophosphate concentration in overlying water and available phosphorus concentration in sediments on day 60. Such increases may be explained by the stimulatory effects of BDE-209 on alkaline phosphatase (ALP) activity and PMB abundance. Moreover, based on Miseq sequencing of the phoD gene encoding ALP, Actinobacteria was the dominant PMB phylum in all treatments, and BDE-209 significantly increased the diversity of PMB and altered their community composition. In particular, the relative abundances of some PMB genera such as Bradyrhizobium were increased significantly after 60 days of the High treatment. A co-occurrence network analysis further revealed that the high level of BDE-209 contamination strengthened the connectivity and interspecific co-operative relationships in the PMB community. These results will help us to understand the effects of POPs on P biogeochemical cycling in eutrophic lakes and the associated microbial mechanisms.


Assuntos
Monitoramento Ambiental , Éteres Difenil Halogenados/análise , Poluentes Químicos da Água/análise , Bactérias , China , Eutrofização , Lagos/microbiologia
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