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1.
PLoS One ; 16(9): e0257017, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34550975

RESUMO

Microbial interactions in harmful algal bloom (HAB) communities have been examined in marine systems, but are poorly studied in fresh waters. To investigate HAB-microbe interactions, we isolated bacteria with close associations to bloom-forming cyanobacteria, Microcystis spp., during a 2017 bloom in the western basin of Lake Erie. The genomes of five isolates (Exiguobacterium sp. JMULE1, Enterobacter sp. JMULE2, Deinococcus sp. JMULE3, Paenibacillus sp. JMULE4, and Acidovorax sp. JMULE5.) were sequenced on a PacBio Sequel system. These genomes ranged in size from 3.1 Mbp (Exiguobacterium sp. JMULE1) to 5.7 Mbp (Enterobacter sp. JMULE2). The genomes were analyzed for genes relating to critical metabolic functions, including nitrogen reduction and carbon utilization. All five of the sequenced genomes contained genes that could be used in potential signaling and nutrient exchange between the bacteria and cyanobacteria such as Microcystis. Gene expression signatures of algal-derived carbon utilization for two isolates were identified in Microcystis blooms in Lake Erie and Lake Tai (Taihu) at low levels, suggesting these organisms are active and may have a functional role during Microcystis blooms in aggregates, but were largely missing from whole water samples. These findings build on the growing evidence that the bacterial microbiome associated with bloom-forming algae have the functional potential to contribute to nutrient exchange within bloom communities and interact with important bloom formers like Microcystis.


Assuntos
DNA Bacteriano/genética , Genoma Bacteriano , Proliferação Nociva de Algas/fisiologia , Metagenoma , Microcystis/genética , Percepção de Quorum/genética , Carbono/metabolismo , Sequenciamento de Nucleotídeos em Larga Escala , Lagos/microbiologia , Microbiota/genética , Microcystis/classificação , Microcystis/metabolismo , Nitrogênio/metabolismo , Oxirredução , Filogenia , Transdução de Sinais , Estados Unidos
2.
Toxins (Basel) ; 13(7)2021 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-34357943

RESUMO

Cyanobacteria are ubiquitous photosynthetic microorganisms considered as important contributors to the formation of Earth's atmosphere and to the process of nitrogen fixation. However, they are also frequently associated with toxic blooms, named cyanobacterial harmful algal blooms (cyanoHABs). This paper reports on an unusual out-of-season cyanoHAB and its dynamics during the COVID-19 pandemic, in Lake Avernus, South Italy. Fast detection strategy (FDS) was used to assess this phenomenon, through the integration of satellite imagery and biomolecular investigation of the environmental samples. Data obtained unveiled a widespread Microcystis sp. bloom in February 2020 (i.e., winter season in Italy), which completely disappeared at the end of the following COVID-19 lockdown, when almost all urban activities were suspended. Due to potential harmfulness of cyanoHABs, crude extracts from the "winter bloom" were evaluated for their cytotoxicity in two different human cell lines, namely normal dermal fibroblasts (NHDF) and breast adenocarcinoma cells (MCF-7). The chloroform extract was shown to exert the highest cytotoxic activity, which has been correlated to the presence of cyanotoxins, i.e., microcystins, micropeptins, anabaenopeptins, and aeruginopeptins, detected by molecular networking analysis of liquid chromatography tandem mass spectrometry (LC-MS/MS) data.


Assuntos
Cianobactérias , Proliferação Nociva de Algas , Lagos/microbiologia , Toxinas Bacterianas/análise , Toxinas Bacterianas/toxicidade , COVID-19/epidemiologia , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Cianobactérias/genética , DNA Bacteriano/análise , Monitoramento Ambiental , Atividades Humanas , Humanos , Itália/epidemiologia , Microcystis , Pandemias , SARS-CoV-2 , Imagens de Satélites
3.
Artigo em Inglês | MEDLINE | ID: mdl-34431766

RESUMO

The aerobic primarily chemoorganotrophic actinobacterial strain MWH-Mo1T was isolated from a freshwater lake and is characterized by small cell lengths of less than 1 µm, small cell volumes of 0.05-0.06 µm3 (ultramicrobacterium), a small genome size of 1.75 Mbp and, at least for an actinobacterium, a low DNA G+C content of 54.6 mol%. Phylogenetic analyses based on concatenated amino acid sequences of 116 housekeeping genes suggested the type strain of Aurantimicrobium minutum affiliated with the family Microbacteriaceae as its closest described relative. Strain MWH-Mo1T shares with the type strain of that species a 16S rRNA gene sequence similarity of 99.6 % but the genomes of the two strains share an average nucleotide identity of only 79.3 %. Strain MWH-Mo1T is in many genomic, phenotypic and chemotaxonomic characteristics quite similar to the type strain of A. minutum. Previous intensive investigations revealed two unusual traits of strain MWH-Mo1T. Although the strain is not known to be phototrophic, the metabolism is adjusted to the diurnal light cycle by up- and down-regulation of genes in light and darkness. This results in faster growth in the presence of light. Additionally, a cell size-independent protection against predation by bacterivorous flagellates, most likely mediated by a proteinaceous cell surface structure, was demonstrated. For the previously intensively investigated aerobic chemoorganotrophic actinobacterial strain MWH-Mo1T (=CCUG 56426T=DSM 107758T), the establishment of the new species Aurantimicrobium photophilum sp. nov. is proposed.


Assuntos
Actinobacteria/classificação , Lagos/microbiologia , Fotoperíodo , Filogenia , Actinobacteria/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
4.
Sci Rep ; 11(1): 16130, 2021 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-34373491

RESUMO

We analyzed phytoplankton assemblages' variations in oligo-mesotrophic Shchuchie and Burabay lakes using traditional morphological and next-generation sequencing (NGS) approaches. The total phytoplankton biodiversity and abundance estimated by both microscopy and NGS were significantly higher in Lake Burabay than in Lake Shchuchie. NGS of 16S and 18S rRNA amplicons adequately identify phytoplankton taxa only on the genera level, while species composition obtained by microscopic examination was significantly larger. The limitations of NGS analysis could be related to insufficient coverage of freshwater lakes phytoplankton by existing databases, short algal sequences available from current instrumentation, and high homology of chloroplast genes in eukaryotic cells. However, utilization of NGS, together with microscopy allowed us to perform a complete taxonomic characterization of phytoplankton lake communities including picocyanobacteria, often overlooked by traditional microscopy. We demonstrate the high potential of an integrated morphological and molecular approach in understanding the processes of organization in aquatic ecosystem assemblages.


Assuntos
Lagos/microbiologia , Fitoplâncton/genética , Biodiversidade , Ecossistema , Citometria de Fluxo , Biblioteca Gênica , Sequenciamento de Nucleotídeos em Larga Escala , Cazaquistão , Microscopia de Contraste de Fase , Parques Recreativos , Fitoplâncton/classificação , Fitoplâncton/ultraestrutura , RNA Ribossômico 16S/genética , RNA Ribossômico 18S/genética
5.
Commun Biol ; 4(1): 845, 2021 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-34234272

RESUMO

The contribution of oxic methane production to greenhouse gas emissions from lakes is globally relevant, yet uncertainties remain about the levels up to which methanogenesis can counterbalance methanotrophy by leading to CH4 oversaturation in productive surface waters. Here, we explored the biogeochemical and microbial community variation patterns in a meromictic soda lake, in the East African Rift Valley (Kenya), showing an extraordinarily high concentration of methane in oxic waters (up to 156 µmol L-1). Vertical profiles of dissolved gases and their isotopic signature indicated a biogenic origin of CH4. A bloom of Oxyphotobacteria co-occurred with abundant hydrogenotrophic and acetoclastic methanogens, mostly found within suspended aggregates promoting the interactions between Bacteria, Cyanobacteria, and Archaea. Moreover, aggregate sedimentation appeared critical in connecting the lake compartments through biomass and organic matter transfer. Our findings provide insights into understanding how hydrogeochemical features of a meromictic soda lake, the origin of carbon sources, and the microbial community profiles, could promote methane oversaturation and production up to exceptionally high rates.


Assuntos
Archaea/crescimento & desenvolvimento , Cianobactérias/crescimento & desenvolvimento , Água Doce/microbiologia , Lagos/microbiologia , Metano/análise , Archaea/classificação , Archaea/genética , Biomassa , Cianobactérias/classificação , Cianobactérias/genética , Cromatografia Gasosa-Espectrometria de Massas , Geografia , Gases de Efeito Estufa/análise , Quênia , RNA Ribossômico 16S/genética
6.
Syst Appl Microbiol ; 44(4): 126225, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34198168

RESUMO

A rhamnose-degrading bacterium, strain BoRhaAT, was isolated from profundal sediment of Lake Constance in agar dilution series with l-rhamnose as substrate and with a background lawn of Methanospirillum hungatei. The isolated strain was a motile rod that stained Gram positive. Growth was observed within a pH range of 4.0-7.5 and a temperature range of 15-30°C. Fermentation products of rhamnose or glucose were acetate, propionate, ethanol, butyrate, and 1-propanol. The G+C content was 40.6% G+C. The dominant fatty acids are C16:1ω9c, i-C13:03OH, C16:0 and C17:1ω8c with 8-21% relative abundance. Polar lipids were glycolipids, phosphatidylethanolamine, phosphoaminolipid and other lipids, of which phosphatidylethanolamine was most abundant. The sequence of the 16S rRNA gene of the new isolate matches the sequence of its closest relative Anaerosporomusa subterranea to 92.4%. A comparison of the genome with this strain showed 60.2% genome-wide average amino acid identity (AAI), comparisons with other type strains showed a maximum of 62.7% AAI. Thus, the definition of a new genus is justified for which we propose the name Pelorhabdus. For strain BoRhaAT, we propose the name Pelorhabdus rhamnosifermentans gen. nov., sp. nov., with strain BoRhaAT (DSM 111565T = JCM 39158T) as the type strain.


Assuntos
Firmicutes/classificação , Sedimentos Geológicos/microbiologia , Lagos , Filogenia , Anaerobiose , Técnicas de Tipagem Bacteriana , DNA Bacteriano/genética , Ácidos Graxos/química , Firmicutes/isolamento & purificação , Lagos/microbiologia , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Ramnose , Análise de Sequência de DNA
7.
PLoS One ; 16(7): e0254967, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34288957

RESUMO

Microcystis is a bloom-forming genus of cyanobacteria with some genotypes that produce highly toxic microcystin hepatotoxins. In waterbodies where biological and physical factors are relatively homogenous, toxin quotas (the average amount of toxin per cell), at a single point in time, are expected to be relatively constant. In this study we challenged this assumption by investigating the spatial distribution of microcystin quotas at a single point in time on two separate occasions in a lake with a major Microcystis bloom. Microcystis cell concentrations varied widely across the lake on both sampling occasions (730- and 137-fold) together with microcystin quotas (148- and 362-fold). Cell concentrations and microcystin quotas were strongly positively correlated (R2 = 0.89, P < 0.001, n = 28; R2 = 0.67, P < 0.001, n = 25). Analysis of Microcystis strains using high-throughput sequencing of the 16S-23S rRNA intergenic spacer region showed no relationship between microcystin quota and the relative abundance of specific sequences. Collectively, the results of this study indicate an association between microcystin production and cell density that magnifies the potential for bloom toxicity at elevated cell concentrations.


Assuntos
Eutrofização , Lagos/microbiologia , Microcistinas , Microcystis , DNA Bacteriano/genética , DNA Intergênico/genética , DNA Ribossômico/genética , Microcistinas/genética , Microcistinas/metabolismo , Microcystis/genética , Microcystis/crescimento & desenvolvimento , RNA Ribossômico 16S/genética , RNA Ribossômico 23S/genética
8.
Sci Rep ; 11(1): 13848, 2021 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-34226571

RESUMO

Metagenomic and traditional paleolimnological approaches are suitable to infer past biological and environmental changes, however, they are often applied independently, especially in tropical regions. We combined both approaches to investigate Holocene Prokaryote and Eukaryote diversity and microbial metabolic pathways in ancient Lake Chalco, Mexico. Here, we report on diversity among a large number of lineages (36,722 OTUs) and functional diversity (27,636,243 non-clustered predicted proteins, and 6,144 annotated protein-family genes). The most abundant domain is Bacteria (81%), followed by Archaea (15%) and Eukarya (3%). We also determined the diversity of protein families and their relationship to metabolic pathways. The early Holocene (> 11,000 cal years BP) lake was characterized by cool, freshwater conditions, which later became warmer and hyposaline (11,000-6,000 cal years BP). We found high abundances of cyanobacteria, and fungi groups associated with mature forests in these sediments. Bacteria and Archaea include mainly anaerobes and extremophiles that are involved in the sulfur, nitrogen, and carbon cycles. We found evidence for early human impacts, including landscape modifications and lake eutrophication, which began ~ 6,000 cal years BP. Subsaline, temperate conditions were inferred for the past 5,000 years. Finally, we found nitrogen-fixing bacteria and protein-family genes that are linked to contaminated environments, as well as several fungal pathogens of crops in near-surface sediments.


Assuntos
Archaea/genética , Bactérias/genética , Lagos/microbiologia , Microbiota/genética , Ciclo do Carbono/genética , Sedimentos Geológicos/microbiologia , Humanos , Metagenoma/genética , México , Nitrogênio/metabolismo , Filogenia , Clima Tropical
9.
J Environ Public Health ; 2021: 6664816, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34285697

RESUMO

The study aims to document the level of contamination of the aquatic ecosystem of the Cotonou-Lake Nokoué canal hydrographic complex by multidrug-resistant bacteria and their resistance genes. For this purpose, water samples were taken from several points of the complex and from the sediments at the depth of the lake. Samples of several species of freshly caught fish products from the lake were also collected. Bacteriological analyses were carried out according to the AFNOR standard (NF U: 47-100). The identification of the different bacterial species isolated was then carried out using the API 20E gallery and specific biochemical tests. The antibiogram of the strains was performed according to the recommendations of the EUCAST. Molecular characterization of the identified strains was carried out by searching for resistance and virulence genes. The results obtained revealed the presence of several bacterial species in water samples and in sediment and intestine samples of fishery products with a predominance of Gram-negative bacilli. The resistance profile of Gram-negative bacilli showed a total resistance to metronidazole (100%). 23% of the strains were also resistant to ciprofloxacin, 41% to amoxicillin, and 60% to aztreonam. Of the Gram-positive cocci identified, 66% was resistant to vancomycin, 7.5% to ciprofloxacin, 71% to erythromycin, and 22% to tetracycline. Regarding the genes sought, bla TEM (46%), bla SHV (24%), and bla CTX-M-15 (31%) were present in the genome of Gram-negative bacilli as resistance genes and fimH (41%) as virulence gene. As for Gram-positive cocci, the van B gene was completely absent. The van A was present at 6.25% in Staphylococcus aureus and mecA at 21.88 and 33.33%, respectively, in Staphylococcus aureus and coagulase-negative staphylococci strains. The high resistance of isolated bacterial strains is a matter of concern and calls for a rational use of antibiotics in order to avoid the transmission of antibiotic resistance from the environment to humans.


Assuntos
Resistência Microbiana a Medicamentos , Lagos , Animais , Antibacterianos/farmacologia , Benin , Resistência Microbiana a Medicamentos/genética , Humanos , Lagos/microbiologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/genética , Staphylococcus aureus/isolamento & purificação
10.
PLoS One ; 16(7): e0254257, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34330143

RESUMO

Griffiths et al. (2017) analyzed several ponds and lakes from the Cape Herschel region of Ellesmere Island in order to "…explicitly examine the role of ice cover as the dominant driver of diatom assemblage change…". I reanalyze their data and suggest that their classification scheme, that they propose is due to differences in ice cover seasonality ("warm", "cool", "cold", and "oasis"), is confounded with other morphological and chemical variables that better explain the differences between the groups. The "cold" sites are the deepest (lakes) and differ from the small, shallow ponds that occasionally dry, which would therefore have different diatom assemblages and histories. The "oasis" sites are nutrient enriched and probably have more stable water supplies, thereby enabling an aquatic flora providing habitats for diatoms. A key part of their interpretation is that "warm" sites have responded more rapidly to recent climate change than "cold" or "cool" sites, but their chronologies do not allow for such a conclusion. There is no clear difference between "cool" and "warm" sites, and problems in dating the sequences means inferences about their histories are not supported by data. Their results, which are restricted to the past century, are contradicted by a Holocene sequence from the region.


Assuntos
Mudança Climática , Diatomáceas/crescimento & desenvolvimento , Camada de Gelo/microbiologia , Lagos/microbiologia , Lagoas/microbiologia , Regiões Árticas , Canadá
11.
Ecotoxicol Environ Saf ; 221: 112427, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34171688

RESUMO

Lakes in arid northwestern China, as the main pollutant-holding water bodies in the typical ecologically fragile areas, are facing the unknown risk of exposure to antibiotics and antibiotic resistance genes (ARGs). In this study, five ARGs and one mobile genetic element (intI1) and their relation with antibiotics, microbial communities and water quality were investigated in Ebinur Lake Basin, a typical salt-lake of China. Quantitative PCR analysis indicated that ARGs decreasing order in both surface water and sediment was sul1 >sul2 >tetW>ermB>qnrS, which means sulfonamide resistance genes were the main pollution ARGs. Macrolide antibiotics were the predominant antibiotics in the surface water and sediment in winter, while sulfonamides and quinolones accounted for a high proportion in summer. There was a non-corresponding relationship between ARGs and antibiotics. Moreover, the relationship between ARGs and microbial communities were defined. Sulfonamide resistance genes were carried by a greater diversity of potential host bacteria (76 genera) than other ARGs (9 genera). And their positive correlation with intI1 (p < 0.05) which promotes their migration and provides possibility of their co-occurrence in bacterial populations (e.g., Nitrospira). Bacterial genera were the main driver of ARGs distribution pattern in highly saline lake sediment. Environmental factors like salinity, total nitrogen and organic matter could have a certain influence on the occurrence of ARGs by affecting microorganisms. The results systematically show the distribution and propagation characteristics of ARGs in typical inland salt-lakes in China, and preliminarily explored the relationship between ARGs and antibiotics, resistance genes and microorganisms in lakes in ecologically fragile areas.


Assuntos
Resistência Microbiana a Medicamentos/genética , Monitoramento Ambiental , Genes Bacterianos/genética , Lagos/microbiologia , Microbiota/efeitos dos fármacos , Microbiota/genética , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , China , Quinolonas/farmacologia , Sulfonamidas/farmacologia , Qualidade da Água
12.
Int Microbiol ; 24(3): 455-470, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34100180

RESUMO

The reemergence of infectious diseases and resistant pathogens represents a serious problem for human life. Hence, the screening for new or alternative antimicrobial compounds is still urgent. Unusual ecosystems such as saline habitats are considered promising environments for the purposes of isolating bacterial strains able to produce potent natural products. The aim of this study is the identification of bioactive compounds biosynthesized by three halotolerant strains isolated from the Sebkha of Oran (Algeria) using gas chromatography coupled to mass spectrometry. Primary screening investigation of antimicrobial activities were performed against reference bacterial and fungal strains and revealed a broad-spectrum activity. Secondary metabolite extraction was carried out using ethyl acetate and chloroform. Crude extracts were tested for bioactivity using the disc diffusion method and subjected to GC-MS analysis. The extracts showed an important inhibitory effect against all tested strains. Fifty-six compounds were identified; they include tert-butyl phenol compounds, fatty acid methyl esters due to the methylation procedure, hydrocarbons, aldehydes, benzoquinones, pyrrols, and terpenes. Literature reports such compounds to have wide biological and pharmaceutical applications. The molecular identification of the three isolates was achieved using the 16S-23S rRNA gene intergenic spacer region (ITS) and 16S rRNA sequencing. Partial 16S rRNA gene sequencing showed very high similarity with many species of Bacillus. This study provided insights on the potential of halotolerant Bacillus as drug research target for bioactive metabolites. The findings suggest that the Great Sebkha of Oran is a valuable source of strains exhibiting variety of beneficial attributes that can be utilized in the development of biological antibiotics.


Assuntos
Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Bacillus licheniformis/metabolismo , Bactérias/efeitos dos fármacos , Fungos/efeitos dos fármacos , Argélia , Bacillus licheniformis/classificação , Bacillus licheniformis/genética , Bacillus licheniformis/isolamento & purificação , DNA Bacteriano , Ecossistema , Cromatografia Gasosa-Espectrometria de Massas/métodos , Lagos/microbiologia , Testes de Sensibilidade Microbiana , RNA Ribossômico 16S , Tolerância ao Sal , Metabolismo Secundário , Microbiologia do Solo
13.
Arch Microbiol ; 203(6): 3695-3705, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33978771

RESUMO

Lago de Tota is the largest highland lake in Colombia and one of the most remarkable of Northern Andean Mountain range. This lake is under an anthropogenic-based eutrophication process as a consequence of non-sustainable agriculture practices developing nearby. Notable relationship between the trophic status and Bacteriome loop dynamics has been increasingly disclosed in lakes worldwide. We performed a 16S sequencing analysis to depict the bacterial community present and we inferred its potential gene function in Lago de Tota. Parameters for determining current trophic condition such as total nitrogen (TN), dissolved carbon (DOC), particulate organic matter (POM), and chlorophyll-a (chl-a) were measured. A total of 440 Operational Taxonomic Units (OTUs) arranged into 50 classes were identified based on V3-V4 regions of the 16S rRNA gene, harboring high-frequent likely found environmental classes such as Actinobacteria, Gammaproteobacteria, Bacteroidia, Acidimicrobia, and Verrucomicrobiae. A total of 26 bacterial classes configure most abundant predicted functional processes involved in organic matter decomposition (i.e., carbohydrate metabolism, amino acid metabolism, xenobiotic biodegradation, and energy metabolism). In general, Actinobacteria, Alphaproteobacteria, and Gammaproteobacteria show the highest potential gene functional contributors, although other low-frequent classes OTUs are also relevant in processes of carbohydrate metabolism, xenobiotic biodegradation, and energy metabolism. The Trophic State Index indicates an oligo-mesotrophic status, and additional variables measured (i.e., POM, DOC) suggest the increasing carbon accumulation. Results provide preliminary evidence for several bacteria groups related to eutrophication of Lago de Tota. Under this picture, we suggest that further studies for Bacteriome loop spatial-temporal description are essential to inform local water quality monitoring strategies.


Assuntos
Bactérias/genética , Eutrofização , Lagos/microbiologia , Colômbia , Microbiota , RNA Ribossômico 16S/genética
14.
Arch Microbiol ; 203(7): 3893-3903, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34008070

RESUMO

Increasing environmental pollutants such as heavy metals have become one of the most severe health dangers because of rapid industrialization. Exposure to lead and nickel heavy toxic metals can lead to hazardous diseases affecting most of the organs in humans. Bioremediation is a process that uses the ability of microorganisms or plants to detoxify environmental contaminants at lower costs than physicochemical techniques. This study isolated halophilic bacteria from Khara salt lake in Iran and screened their ability to resist lead and nickel. After screening stages, three selected strains including Bacillus sp. A21, Oceanobacillus sp. A22 and Salinicoccus A43 were identified by16S rDNA sequencing and the related sequences were submitted to GeneBank with accession IDs MN588312, MN588313, and MN 588,314, respectively. These strains resist 7.2 mM, 4.1 mM, and 6.7 mM lead and 3.6 mM, 3.7 mM, and 4.1 mM nickel, respectively. Investigation of growth pattern and evaluation of bioremediation ability by atomic absorption spectroscopy revealed that Bacillus sp. A21 could decrease lead and nickel in culture medium up to 97.5% and 76%, respectively. Oceanobacillus sp. A22 showed higher lead bioremediation rate (98.8%) and lower nickel-bioremediation rate (73.5%). Salinicoccus sp. A43 showed the least bioremediation ability (92% lead and 71.7% nickel). The ability of selected strains to synthesize lead and nickel nanoparticles was evaluated using UV/Vis spectrophotometry and Energy-Dispersive X-ray Spectroscopy (EDX). Particle dimensions were measured using Scanning Electron Microscopy (SEM). Bacillus sp. A21 and Oceanobacillus sp. A22 strains were able to synthesize lead nanoparticles; however, Salinicoccus sp. A43 could synthesize both lead and nickel nanoparticles.


Assuntos
Bactérias , Biodegradação Ambiental , Metais Pesados , Nanopartículas , Bactérias/genética , Bactérias/metabolismo , Irã (Geográfico) , Lagos/microbiologia , Metais Pesados/metabolismo , Nanopartículas/química , Nanopartículas/metabolismo
15.
World J Microbiol Biotechnol ; 37(6): 91, 2021 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-33939019

RESUMO

Ammonia-oxidizing microorganisms (AOM) play crucial roles in the degradation of ammonia nitrogen in freshwater lakes. Hence, it is necessary to reveal the spatiotemporal dynamic changes of AOM in freshwater lakes. Here, we conducted a study on the spatial and temporal dynamic changes of AOM in different lake regions under gradient nutrient levels in Lake Taihu, and found that the abundance of AOM had significant spatial changes, while the seasonal changes had relatively little effect on the abundance of AOM. We also found that ammonia-oxidizing archaea (AOA) were adapted to freshwater habitats with low nutrient levels, while ammonia-oxidizing bacteria (AOB) and anaerobic ammonia-oxidizing bacteria (AAOB) had higher abundance in high nutrient level lake regions. Moreover, the amoA gene abundance of AOB was much higher than that of AOA, indicating that AOB was the dominant aerobic ammonia oxidizer in the water of Lake Taihu. In addition, temperature, pH and dissolved oxygen all had a positive effect on AOM, especially AOB; while C- and N-related physicochemical factors had a significant positive effect on AAOB, but exhibited a significant negative correlation with AOA. The community structure of AOM also had obvious spatial changes and Group I.1a, Nitrosomonas and Candidatus Brocadia fulgida were the dominant cluster of AOA, AOB and AAOB, respectively.


Assuntos
Amônia/química , Archaea/classificação , Bactérias/classificação , Lagos/microbiologia , Nutrientes/análise , Archaea/genética , Archaea/isolamento & purificação , Proteínas Arqueais/genética , Bactérias/genética , Bactérias/isolamento & purificação , Proteínas de Bactérias/genética , China , Sedimentos Geológicos/microbiologia , Concentração de Íons de Hidrogênio , Lagos/química , Oxirredução , Filogenia , Estações do Ano , Análise Espaço-Temporal
16.
PLoS One ; 16(5): e0250783, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33939728

RESUMO

Lake sediments are natural archives that accumulate information on biological communities and their surrounding catchments. Paleolimnology has traditionally focussed on identifying fossilized organisms to reconstruct past environments. In the last decade, the application of molecular methodologies has increased in paleolimnological studies, but further research investigating factors such as sample heterogeneity and DNA degradation are required. In the present study we investigated bacterial community heterogeneity (16S rRNA metabarcoding) within depth slices (1-cm width). Sediment cores were collected from three lakes with differing sediment compositions. Samples were collected from a variety of depths which represent a period of time of approximately 1,200 years. Triplicate samples were collected from each depth slice and bacterial 16S rRNA metabarcoding was undertaken on each sample. Accumulation curves demonstrated that except for the deepest (oldest) slices, the combination of three replicate samples were insufficient to characterise the entire bacterial diversity. However, shared Amplicon Sequence Variants (ASVs) accounted for the majority of the reads in each depth slice (max. shared proportional read abundance 96%, 86%, 65% in the three lakes). Replicates within a depth slice generally clustered together in the Non-metric multidimensional scaling analysis. There was high community dissimilarity in older sediment in one of the cores, which was likely due to the laminae in the sediment core not being horizontal. Given that most paleolimnology studies explore broad scale shifts in community structure rather than seeking to identify rare species, this study demonstrates that a single sample is adequate to characterise shifts in dominant bacterial ASVs.


Assuntos
DNA Ambiental/análise , Sedimentos Geológicos/microbiologia , Lagos/microbiologia , DNA Ambiental/genética , Microbiota
17.
Sci Data ; 8(1): 131, 2021 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-33990618

RESUMO

Stratified lakes and ponds featuring steep oxygen gradients are significant net sources of greenhouse gases and hotspots in the carbon cycle. Despite their significant biogeochemical roles, the microbial communities, especially in the oxygen depleted compartments, are poorly known. Here, we present a comprehensive dataset including 267 shotgun metagenomes from 41 stratified lakes and ponds mainly located in the boreal and subarctic regions, but also including one tropical reservoir and one temperate lake. For most lakes and ponds, the data includes a vertical sample set spanning from the oxic surface to the anoxic bottom layer. The majority of the samples were collected during the open water period, but also a total of 29 samples were collected from under the ice. In addition to the metagenomic sequences, the dataset includes environmental variables for the samples, such as oxygen, nutrient and organic carbon concentrations. The dataset is ideal for further exploring the microbial taxonomic and functional diversity in freshwater environments and potential climate change impacts on the functioning of these ecosystems.


Assuntos
Lagos/microbiologia , Metagenoma , Microbiota/genética , Oxigênio/análise , Lagoas/microbiologia , Archaea/classificação , Archaea/genética , Bactérias/classificação , Bactérias/genética , Ciclo do Carbono , Mudança Climática , Gases de Efeito Estufa/análise , Lagos/química , Filogenia , Lagoas/química
18.
PLoS One ; 16(5): e0251065, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33956828

RESUMO

The supply of drinking water is a vital challenge for the people who live on the African continent, as this continent is experiencing strong demographic growth and therefore increasing water demands. To meet these needs, surface water resources are becoming increasingly mobilized because underground resources are not always available or have already been overexploited. This situation is the case in the region of Abidjan in the Ivory Coast, where the drinking water deficit is a growing problem and it is therefore necessary to mobilize new water resources to ensure the supply of drinking water. Among the potential resources, local managers have identified a freshwater lagoon, Lagoon Aghien, That is in close proximity to the city of Abidjan. With the aim of enhancing knowledge on the ecological functioning of the lagoon and contributing to the assessment of its ability to provide drinking water, several physical and chemical parameters of the water and the phytoplankton community of the lagoon were monitored for 17 months (December 2016-April 2018) at six sampling stations. Our findings show that the lagoon is eutrophic, as evidenced by the high concentrations of total phosphorus (>140 µg L-1), nitrogen (1.36 mg L-1) and average chlorophyll-a (26 to 167 µg L-1) concentrations. The phytoplankton community in the lagoon is dominated by genera typical of eutrophic environments including mixotrophic genera such as Peridinium and by cyanobacteria such as Cylindrospermopsis/Raphidiopsis, Microcystis and Dolichospermum that can potentially produce cyanotoxins. The two rainfall peaks that occur in June and October appeared to be major events in terms of nutrient flows entering the lagoon, and the dynamics of these flows are complex. Significant differences were also found in the nutrient concentrations and to a lesser extent in the phytoplankton communities among the different stations, especially during the rainfall peaks. Overall, these results reveal that the quality of the lagoon's water is already severely degraded, and this degradation could increase in future years due to increasing urbanization in the watershed. These results therefore raise questions about the potential use of the lagoon as a source of drinking water if measures are not taken very quickly to protect this lagoon from increasing eutrophication and other pollution sources.


Assuntos
Ecologia , Lagos , Clorofila A/análise , Costa do Marfim , Água Doce , Lagos/química , Lagos/microbiologia , Nutrientes/análise , Fitoplâncton , Estações do Ano , Análise Espaço-Temporal
19.
Nat Commun ; 12(1): 2406, 2021 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-33893318

RESUMO

Understanding Earth's response to climate forcing in the geological past is essential to reliably predict future climate change. The reconstruction of continental climates, however, is hampered by the scarcity of universally applicable temperature proxies. Here, we show that heterocyte glycolipids (HGs) of diazotrophic heterocytous cyanobacteria occur ubiquitously in equatorial East African lakes as well as polar to tropical freshwater environments. The relative abundance of HG26 diols and keto-ols, quantified by the heterocyte diol index (HDI26), is significantly correlated with surface water temperature (SWT). The first application of the HDI26 to a ~37,000 year-long sediment record from Lake Tanganyika provides evidence for a ~4.1 °C warming in tropical East Africa from the last glacial to the beginning of the industrial period. Given the worldwide distribution of HGs in lake sediments, the HDI26 may allow reconstructing SWT variations in polar to tropical freshwater environments and thereby quantifying past continental climate change.


Assuntos
Mudança Climática , Cianobactérias/metabolismo , Água Doce/microbiologia , Glicolipídeos/metabolismo , Lagos/microbiologia , Calibragem , Cianobactérias/citologia , Geografia , Sedimentos Geológicos/microbiologia , Tanzânia , Temperatura
20.
Arch Microbiol ; 203(6): 3135-3146, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33813595

RESUMO

The present study is the first of its kind which is focused on Tsomgo lake, a high-altitude lake, located in the Eastern Himalayas of Sikkim. To get a major insight into the bacterial diversity, the shotgun sequencing was carried out in Illumina platform. Our results showed that both the samples TLSS1 (soil) and TLSW1 (water), had Proteobacteria as the most abundant taxa. Cluster of Orthologous group (COG) functional category of TLSS1 has 1,46,965 predicted functions. Cluster of Orthologous Group (COG) functional category of TLSW1 has 1,34,773 predicted functions. Kyoto Encyclopedia of Gene and Genomes (KEGG) functional category of TLSS1 has 1,76,825 predicted functions, most of the sequence fall in metabolism followed by Environmental information processing function. (KEGG) functional category of TLSW1 has 1,62,696 predicted functions and it follows the same pattern as TLSS1. Our studies also provide insight into the presence of distribution of different carbohydrate-active enzymes (CAZymes) present in Tsomgo lake. We have found that in case of both the samples TLSW1 and TLSS1, GlycosylTransferases were active followed by GlycosylHydrolase. The result found, represents for the first time very important findings related to the microbial diversity and the abundance of CAZymes in Tsomgo lake one of the pristine high-altitude lakes in Sikkim.


Assuntos
Bactérias , Enzimas , Lagos , Metagenômica , Microbiota , Microbiologia do Solo , Bactérias/classificação , Bactérias/enzimologia , Bactérias/genética , Enzimas/genética , Índia , Lagos/microbiologia , Microbiota/genética , Filogenia
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