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1.
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
2.
Microbiome ; 7(1): 55, 2019 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-30944036

RESUMO

BACKGROUND: Biological soil crusts (biocrusts) are a key component of arid land ecosystems, where they render critical services such as soil surface stabilization and nutrient fertilization. The bundle-forming, filamentous, non-nitrogen-fixing cyanobacterium Microcoleus vaginatus is a pioneer primary producer, often the dominant member of the biocrust microbiome, and the main source of leaked organic carbon. We hypothesized that, by analogy to the rhizosphere of plant roots, M. vaginatus may shape the microbial populations of heterotrophs around it, forming a specialized cyanosphere. RESULTS: By physically isolating bundles of M. vaginatus from biocrusts, we were able to study the composition of the microbial populations attached to it, in comparison to the bulk soil crust microbiome by means of high-throughput 16S rRNA sequencing. We did this in two M. vaginatus-dominated biocrust from distinct desert biomes. We found that a small, selected subset of OTUs was significantly enriched in close proximity to M. vaginatus. Furthermore, we also found that a majority of bacteria (corresponding to some two thirds of the reads) were significantly more abundant away from this cyanobacterium. Phylogenetic placements suggest that all typical members of the cyanosphere were copiotrophs and that many were diazotrophs (Additional file 1: Tables S2 and S3). Nitrogen fixation genes were in fact orders of magnitude more abundant in this cyanosphere than in the bulk biocrust soil as assessed by qPCR. By contrary, competition for light, CO2, and low organic carbon concentrations defined at least a part of the OTUs segregating from the cyanobacterium. CONCLUSIONS: We showed that M. vaginatus acts as a significant spatial organizer of the biocrust microbiome. On the one hand, it possesses a compositionally differentiated cyanosphere that concentrates the nitrogen-fixing function. We propose that a mutualism based on C for N exchange between M. vaginatus and copiotrophic diazotrophs helps sustains this cyanosphere and that this consortium constitutes the true pioneer community enabling the colonization of nitrogen-poor soils. On the other hand, a large number of biocrust community members segregate away from the vicinity of M. vaginatus, potentially through competition for light or CO2, or because of a preference for oligotrophy.


Assuntos
Cianobactérias/classificação , Fixação de Nitrogênio , RNA Ribossômico 16S/genética , Cianobactérias/genética , Cianobactérias/isolamento & purificação , DNA Ribossômico/genética , Clima Desértico , Filogenia , Microbiologia do Solo , Simbiose
3.
J Microbiol ; 57(6): 450-460, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31012060

RESUMO

Next-generation DNA sequencing technology was applied to generate molecular data from semiarid reservoirs during well-defined seasons. Target sequences of 16S-23S rRNA ITS and cpcBA-IGS were used to reveal the taxonomic groups of cyanobacteria present in the samples, and genes coding for cyanotoxins such as microcystins (mcyE), saxitoxins (sxtA), and cylindrospermopsins (cyrJ) were investigated. The presence of saxitoxins in the environmental samples was evaluated using ELISA kit. Taxonomic analyses of high-throughput DNA sequencing data showed the dominance of the genus Microcystis in Mundaú reservoir. Furthermore, it was the most abundant genus in the dry season in Ingazeira reservoir. In the rainy season, 16S-23S rRNA ITS analysis revealed that Cylindrospermopsis raciborskii comprised 46.8% of the cyanobacterial community in Ingazeira reservoir, while the cpcBAIGS region revealed that C. raciborskii (31.8%) was the most abundant taxon followed by Sphaerospermopsis aphanizomenoides (17.3%) and Planktothrix zahidii (16.6%). Despite the presence of other potential toxin-producing genera, the detected sxtA gene belonged to C. raciborskii, while the mcyE gene belonged to Microcystis in both reservoirs. The detected mcyE gene had good correlation with MC content, while the amplification of the sxtA gene was related to the presence of STX. The cyrJ gene was not detected in these samples. Using DNA analyses, our results showed that the cyanobacterial composition of Mundaú reservoir was similar in successive dry seasons, and it varied between seasons in Ingazeira reservoir. In addition, our data suggest that some biases of analysis influenced the cyanobacterial communities seen in the NGS output of Ingazeira reservoir.


Assuntos
Biodiversidade , Cianobactérias/classificação , Cianobactérias/isolamento & purificação , Água Potável/microbiologia , Análise de Sequência de DNA/métodos , Microbiologia da Água , Abastecimento de Água , Toxinas Bacterianas/análise , Toxinas Bacterianas/genética , Toxinas Bacterianas/isolamento & purificação , Brasil , Cianobactérias/genética , DNA Bacteriano/análise , Monitoramento Ambiental/métodos , Genes Bacterianos/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Metagenômica/métodos , Microcystis/genética , RNA Ribossômico 16S/genética , RNA Ribossômico 23S/genética , Saxitoxina/genética , Estações do Ano , Uracila/análogos & derivados
4.
Chemosphere ; 225: 342-351, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30884295

RESUMO

Fast Detection Strategy for Cyanobacterial blooms and associated Cyanotoxins (FDSCC) is a multidisciplinary strategy that allows early detection, in 24 man-hours, of cyanobacteria and related cyanotoxins in water and bivalve samples. This approach combines the advantages of remote/proximal sensing with those of analytical/bioinformatics analyses, namely, LC-HRMS-based molecular networking. The detection of Lyngbyatoxin A, a lipophilic cyanotoxin, in all analyzed water samples and in bivalves, commonly used as food, was the proof of the reliability of the new method.


Assuntos
Cianobactérias/isolamento & purificação , Proliferação Nociva de Algas , Toxinas da Lyngbya/análise , Microcistinas/análise , Animais , Toxinas Bacterianas/análise , Bivalves/química , Bivalves/microbiologia , Itália , Reprodutibilidade dos Testes
5.
Int. microbiol ; 22(1): 49-58, mar. 2019. ilus, graf
Artigo em Inglês | IBECS | ID: ibc-184813

RESUMO

Green route for silver nanoparticle synthesis has gained increasing attention. Cyanobacteria are one of the promising organisms to produce a number of secondary metabolites that are capable of reducing silver ions to small-sized silver nanoparticles. In the present study, we employed an aqueous extract of the cyanobacterium Haloleptolyngbya alcalis KR2005/106 isolated from a soda lake for biosynthesis of silver nanoparticles (AgNPs). The extract acted as a reducing agent for AgNPs synthesis and resulted formation of nanoparticles <50 nm in size. In this study, synthesis of AgNPs obtained only in the sample exposed to photosynthetically active radiation (PAR) while the synthesis of AgNPs was not observed in the samples kept in dark. The biogenic fabrication of AgNPs was carried out by optimizing several governing parameters such as concentration of the silver nitrate solution, pH, temperature, and amount of biomass. Results obtained through different analytical techniques revealed that cyanobacterial taxon H. alcalis isolated from saline-alkaline habitat is a potential candidate for biosynthesis of optimum-sized spherical AgNPs. Surface plasmon resonance (SPR) property of AgNPs was exploited for aqueous ammonia sensing and revealed that AgNPs synthesized using aqueous extract of cyanobacterium H. alcalis could be employed for colorimetric detection of dissolved ammonia for monitoring quality of water


No disponible


Assuntos
Amônia/análise , Misturas Complexas/metabolismo , Cianobactérias/metabolismo , Nanopartículas Metálicas , Prata/metabolismo , Nitrato de Prata/metabolismo , Cianobactérias/isolamento & purificação , Escuridão , Lagos/microbiologia , Luz , Oxirredução , Ressonância de Plasmônio de Superfície
6.
ISME J ; 13(6): 1618-1634, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30809011

RESUMO

Blooms of planktonic cyanobacteria have long been of concern in lakes, but more recently, harmful impacts of riverine benthic cyanobacterial mats been recognized. As yet, we know little about how various benthic cyanobacteria are distributed in river networks, or how environmental conditions or other associated microbes in their consortia affect their biosynthetic capacities. We performed metagenomic sequencing for 22 Oscillatoriales-dominated (Cyanobacteria) microbial mats collected across the Eel River network in Northern California and investigated factors associated with anatoxin-a producing cyanobacteria. All microbial communities were dominated by one or two cyanobacterial species, so the key mat metabolisms involve oxygenic photosynthesis and carbon oxidation. Only a few metabolisms fueled the growth of the mat communities, with little evidence for anaerobic metabolic pathways. We genomically defined four cyanobacterial species, all which shared <96% average nucleotide identity with reference Oscillatoriales genomes and are potentially novel species in the genus Microcoleus. One of the Microcoleus species contained the anatoxin-a biosynthesis genes, and we describe the first anatoxin-a gene cluster from the Microcoleus clade within Oscillatoriales. Occurrence of these four Microcoleus species in the watershed was correlated with total dissolved nitrogen and phosphorus concentrations, and the species that contains the anatoxin-a gene cluster was found in sites with higher nitrogen concentrations. Microbial assemblages in mat samples with the anatoxin-a gene cluster consistently had a lower abundance of Burkholderiales (Betaproteobacteria) species than did mats without the anatoxin-producing genes. The associations of water nutrient concentrations and certain co-occurring microbes with anatoxin-a producing Microcoleus motivate further exploration for their roles as potential controls on the distributions of toxigenic benthic cyanobacteria in river networks.


Assuntos
Cianobactérias/isolamento & purificação , Cianobactérias/metabolismo , Rios/microbiologia , Tropanos/metabolismo , California , Cianobactérias/classificação , Cianobactérias/genética , Lagos/microbiologia , Metagenômica , Nitrogênio/metabolismo , Fósforo/metabolismo , Filogenia , Rios/química
7.
Int Microbiol ; 22(1): 49-58, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30810931

RESUMO

Green route for silver nanoparticle synthesis has gained increasing attention. Cyanobacteria are one of the promising organisms to produce a number of secondary metabolites that are capable of reducing silver ions to small-sized silver nanoparticles. In the present study, we employed an aqueous extract of the cyanobacterium Haloleptolyngbya alcalis KR2005/106 isolated from a soda lake for biosynthesis of silver nanoparticles (AgNPs). The extract acted as a reducing agent for AgNPs synthesis and resulted formation of nanoparticles < 50 nm in size. In this study, synthesis of AgNPs obtained only in the sample exposed to photosynthetically active radiation (PAR) while the synthesis of AgNPs was not observed in the samples kept in dark. The biogenic fabrication of AgNPs was carried out by optimizing several governing parameters such as concentration of the silver nitrate solution, pH, temperature, and amount of biomass. Results obtained through different analytical techniques revealed that cyanobacterial taxon H. alcalis isolated from saline-alkaline habitat is a potential candidate for biosynthesis of optimum-sized spherical AgNPs. Surface plasmon resonance (SPR) property of AgNPs was exploited for aqueous ammonia sensing and revealed that AgNPs synthesized using aqueous extract of cyanobacterium H. alcalis could be employed for colorimetric detection of dissolved ammonia for monitoring quality of water.


Assuntos
Amônia/análise , Misturas Complexas/metabolismo , Cianobactérias/metabolismo , Nanopartículas Metálicas , Prata/metabolismo , Colorimetria/métodos , Cianobactérias/isolamento & purificação , Escuridão , Lagos/microbiologia , Luz , Oxirredução , Nitrato de Prata/metabolismo , Ressonância de Plasmônio de Superfície
8.
J Microbiol ; 57(4): 243-251, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30721458

RESUMO

Various Nostoc spp. and related cyanobacteria are able to survive extreme temperatures and are among the most successful colonists of high-elevation sites being exposed due to glacial retreat. It is unclear, however, if cyanobacteria can grow during the extreme freeze-thaw cycles that occur on a year-round basis at high-elevation, peri-glacial sites or if they only grow during the rare periods when freeze-thaw cycles do not occur. We conducted several experiments to determine if cyanobacteria that form biological soil crusts (BSCs) at high-elevation sites (> 5,000 m.a.s.l.) in the Andes can grow during diurnal freeze-thaw cycles on a par with those that occur in the field. Here we show that a soil crust that had been frozen at -20°C for five years was able to increase from 40% to 100% soil coverage during a 45-day incubation during which the soil temperature cycled between -12°C and 26°C every day. In a second, experiment an undeveloped soil with no visible BSCs showed a statistically significant shift in the bacterial community from one containing few cyanobacterial sequences (8% of sequences) to one dominated (27%) by Nostoc, Microcoleus, and Leptolyngbya phylotypes during a 77-day incubation with daily freeze-thaw cycles. In addition, counts of spherical Nostoc-like colonies increased significantly on the soil surface during the experiment, especially in microcosms receiving phosphorus. Taken together these results show that freeze-thaw cycles alone do not limit the growth of BSCs in high-elevation soils, and provide new insight into how life is able to thrive in one of the most extreme terrestrial environments on Earth.


Assuntos
Cianobactérias/crescimento & desenvolvimento , Microbiologia do Solo , Solo/química , Cianobactérias/classificação , Cianobactérias/genética , Cianobactérias/isolamento & purificação , Congelamento , Temperatura Ambiente
9.
Geobiology ; 17(3): 308-319, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30707499

RESUMO

Bacteriohopanepolyols (BHPs) are bacterial membrane lipids that may be used as biological or environmental biomarkers. Previous studies have described the diversity, distribution, and abundance of BHPs in a variety of modern environments. However, the regulation of BHP production in polar settings is not well understood. Benthic microbial mats from ice-covered lakes of the McMurdo Dry Valleys, Antarctica provide an opportunity to investigate the sources, physiological roles, and preservation of BHPs in high-latitude environments. Lake Vanda is one of the most stable lakes on Earth, with microbial communities occupying specific niches along environmental gradients. We describe the influence of mat morphology and local environmental conditions on the diversity and distribution of BHPs and their biological sources in benthic microbial mats from Lake Vanda. The abundance and diversity of C-2 methylated hopanoids (2-MeBHP) are of particular interest, given that their stable degradation products, 2-methylhopanes, are among the oldest and most prevalent taxonomically informative biomarkers preserved in sedimentary rocks. Furthermore, the interpretation of sedimentary 2-methylhopanes is of great interest to the geobiology community. We identify cyanobacteria as the sole source of 2-MeBHP in benthic microbial mats from Lake Vanda and assess the hypothesis that 2-MeBHP are regulated in response to a particular environmental variable, namely solar irradiance.


Assuntos
Cianobactérias/metabolismo , Lagos/química , Lipídeos de Membrana/análise , Regiões Antárticas , Cianobactérias/isolamento & purificação , Meio Ambiente , Camada de Gelo , Lagos/microbiologia
10.
Mol Phylogenet Evol ; 134: 300-310, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30685417

RESUMO

Cyanobacteria are natural enormous sources of various biologically active compounds with great contributions in different industries. This study aimed to explore and characterize novel cyanobacterial isolates with antioxidant activity and potent phycoremediation ability from Egyptian wastewater canals. The in vitro biological activity of these isolates and their potential ability to take up nutrients and heavy metals from wastewater were examined. The obtained isolates were sequenced and deposited in database under accession numbers, KY250420.1, KY321359.1, KY296359.1 and KU373076.1 for Nostoc calcicola, Leptolyngbya sp., Nostoc sp., and Nostoc sp., respectively. Leptolyngbya sp. (KY321359.1) showed the lowest identity (90%) with the nearest deposited sequence in database. While the isolate Nostoc sp. (KU373076.1) showed the highest total phenolic content as well as the highest levels of caffeic, ferulic and gallic acids. Consequently, it presented the highest antioxidant scavenging activity. All studied isolates revealed potent ability in chelating nutrients and removing heavy metals from wastewater. In conclusion, this study provides a taxonomic, biochemical and molecular evidence of four novel cyanobacterial isolates with antioxidant activity and potential phycoremediation ability.


Assuntos
Antioxidantes/farmacologia , Cianobactérias/isolamento & purificação , Poluição da Água , Biodegradação Ambiental , Compostos de Bifenilo/química , Cianobactérias/classificação , Fenóis/farmacologia , Filogenia , Picratos/química , Polimorfismo de Nucleotídeo Único/genética , RNA Ribossômico 16S/genética , Mapeamento por Restrição , Águas Residuárias , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água
11.
J Appl Microbiol ; 126(4): 1278-1289, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30633843

RESUMO

AIMS: Cyanobacteria are immense sources of several pharmacological active compounds such as flavonoids and carotenoids with anti-inflammatory and antioxidant activity. The potential therapeutic effect of two novel cyanobacterial isolates, Cronbergia siamensis (KY296358.1) and Sphaerospermopsis aphanizomenoides (KU212886.1), against hydrogen peroxide (H2 O2 )-induced oxidative stress damage in the rat model was determined in this study. METHODS AND RESULTS: In vitro antioxidant activity of the two studied isolates was evaluated by radical scavenging assay and ferric reducing power. The possible prophylactic activity of S. aphanizomenoides (KU212886.1) against H2 O2 -induced oxidative stress in the rat model was assessed in vivo. Serum alanine transaminase and aspartate transaminase were measured for the liver functions in redox rats. Liver malondialdehyde (MDA), glutathione, oxidized glutathione, nitric oxide, superoxide dismutase (SOD) and catalase (CAT) were assessed as oxidative stress markers. The effect of S. aphanizomenoides on the transcripts level of superoxide dismutase (Mn-SOD) and catalase (CAT) genes in the rat's liver tissues was measured using qRT-PCR. Oral administration of S. aphanizomenoides extract in low and high doses (100, 200 mg kg-1 b.w) resulted in significant improvement in biochemical parameters of liver functions and oxidative stress markers. Also, the endogenous antioxidant defence enzymes and the expression of their related genes (Mn/SOD, CAT) were upregulated. Immunohistochemistry of Caspase-3, an apoptotic marker, showed potent amelioration in the liver tissues. CONCLUSIONS: The novel isolate S. aphanizomenoides proved in vitro and in vivo antioxidant activity against redox rat model. SIGNIFICANCE AND IMPACT OF THE STUDY: This isolate provides a new source of pharmacological compounds with great importance in pharmacological and medical fields.


Assuntos
Antioxidantes/uso terapêutico , Cianobactérias/fisiologia , Estresse Oxidativo/efeitos dos fármacos , Animais , Antioxidantes/administração & dosagem , Antioxidantes/metabolismo , Cianobactérias/isolamento & purificação , Modelos Animais de Doenças , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Peróxido de Hidrogênio/toxicidade , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Ratos , Espécies Reativas de Oxigênio/metabolismo
12.
FEMS Microbiol Lett ; 366(2)2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30629176

RESUMO

Diatom diazotroph associations (DDAs) are a widespread marine planktonic symbiosis between several diatom genera and di-nitrogen (N2)-fixing bacteria. Combining single cell confocal microscopy observations and molecular genetic approaches on individual field collected cells, we determined the phylogenetic diversity, distribution and evolution of the DDAs. Confocal analyses coupled with 3-D imaging re-evaluated the cellular location of DDA symbionts. DDA diversity was resolved by paired gene sequencing (18S rRNA and rbcL genes, 16S rRNA and nifH genes). A survey using the newly acquired sequences against public databases found sequences with high similarity (99-100%) to either host (18S rRNA) or symbiont (16S rRNA) in atypical regions for DDAs (high latitudes, anoxic basin and copepod gut). Concatenated phylogenies were congruent for the host and cyanobacteria sequences and implied co-evolution. Time-calibrated trees dated the appearance of N2 fixing planktonic symbiosis from 100-50Mya and were consistent with the symbiont cellular location: symbioses with internal partners are more ancient. An ancestral state reconstruction traced the evolution of traits in DDAs and highlight that the adaptive radiation to the marine environment was likely facilitated by the symbiosis. Our results present the evolutionary nature of DDAs and provide new genetic and phenotypic information for these biogeochemically relevant populations.


Assuntos
Evolução Biológica , Cianobactérias/genética , Diatomáceas/genética , Variação Genética , Simbiose , Cianobactérias/classificação , Cianobactérias/isolamento & purificação , Cianobactérias/fisiologia , Diatomáceas/classificação , Diatomáceas/microbiologia , Diatomáceas/fisiologia , Fixação de Nitrogênio , Filogenia , Água do Mar/microbiologia , Água do Mar/parasitologia
13.
Extremophiles ; 23(1): 35-48, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30284641

RESUMO

Genotypic and morphological diversity of cyanobacteria in the Rupite hot spring (Bulgaria) was investigated by means of optical microscopy, cultivation, single-cell PCR, and 16S rRNA gene amplicon sequencing. Altogether, 34 sites were investigated along the 71-39 °C temperature gradient. Analysis of samples from eight representative sites shown that Illumina, optical microscopy, and Roche 454 identified 72, 45 and 19% respective occurrences of all cumulatively present taxa. Optical microscopy failed to detect species of minor occurrence; whereas, amplicon sequencing technologies suffered from failed primer annealing and the presence of species with extensive extracellular polysaccharides production. Amplicon sequencing of the 16S rRNA gene V5-V6 region performed by Illumina identified the cyanobacteria most reliably to the generic level. Nevertheless, only the combined use of optical microscopy, cultivation and sequencing methods allowed for reliable estimate of the cyanobacterial diversity. Here, we show that Rupite hot-spring system hosts one of the richest cyanobacterial flora reported from a single site above 50 °C. Chlorogloeopsis sp. was the most abundant at the highest temperature (68 °C), followed by Leptolyngbya boryana, Thermoleptolyngbya albertanoae, Synechococcus bigranulatus, Oculatella sp., and Desertifilum sp. thriving above 60 °C, while Leptolyngbya geysericola, Geitlerinema splendidum, and Cyanobacterium aponinum were found above 50 °C.


Assuntos
Cianobactérias/genética , Fontes Termais/microbiologia , Microbiota , Cianobactérias/classificação , Cianobactérias/citologia , Cianobactérias/isolamento & purificação , RNA Ribossômico 16S/genética
14.
Chemosphere ; 215: 1-7, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30300806

RESUMO

Increasing micropollutant and cyanobacterial contamination of drinking water threatens human health worldwide. However, these contaminates are not efficiently removed by common drinking water treatment processes, and thus additional treatments are frequently required. Recent investigations have demonstrated that KMnO4 pre-oxidation can efficiently remove some micropollutants and cyanobacteria but the release of cyanobacterial toxins and Mn2+ limit its use. To overcome these problems, we proposed a KMnO4 pre-oxidation coupled with bioaugmentation (e.g., sand filtration) method to treat micropollutant- and cyanobacteria-laden water. We used 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid (BP-4, a common micropollutant in drinking water sources) and Microcystis aeruginosa (a widely distributed cyanobacterial species) as model pollutants to verify the feasibility of the proposed method. Results revealed that KMnO4 pre-oxidation efficiently removed existing natural organic matter and Microcystis aeruginosa but failed to remove BP-4 and released Mn2+ and microcystin-LR (MC-LR) during treatment. Following the addition of a manganese-oxidizing bacterial strain (Pseudomonas sp. QJX-1) to the KMnO4-treated solution, we found that the bacteria could transform Mn2+ to Mn(III&IV) oxides, with the formed Mn oxides then able to remove BP-4 and MC-LR. Overall, the proposed method exhibited advantages in the removal of natural organic matter (i.e., decreasing disinfection byproduct formation), micropollutants, and cyanobacteria as well as preventing the release of Mn2+, and thus may be considered a good alternative for treating polluted drinking water.


Assuntos
Biodegradação Ambiental , Cianobactérias/isolamento & purificação , Desinfecção/métodos , Água Potável/química , Permanganato de Potássio/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Cianobactérias/metabolismo , Água Potável/análise , Humanos , Oxirredução
15.
Arch Microbiol ; 201(2): 199-208, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30506399

RESUMO

Plant endophytes play a crucial role in plant growth, health and ecological function. Jingbai pear (the best quality cultivar of Pyrus ussuriensi Maxim. ex Rupr.) has important ecological and economic value in north China. Conversation of its genetics has great meanings to pear genus (Pyrus L.). However, the bacterial community associated with the cultivar remains unknown. In this study, the structure of endophytic bacterial communities associated with different tissues and soil of Jingbai Pear trees was analyzed with Illumina Miseq sequencing of bacterial 16S rDNA. This is the first report on bacterial microbiome associated with Jingbai pear. Our results demonstrated that different tissues harbored a unique bacterial assemblage. Interestingly, Cyanobacteria was the most abundant phylum, followed by Proteobacteria and Actinobacteria. Samples from three different sites (soils) had significant differences in microbial communities structure. Redundancy analysis (RDA) showed that the bacterial community structure correlated significantly with soil properties-temperature, pH, nitrogen and carbon contents. The conclusion could facilitate to understand the interaction and ecological function of endophytic bacteria with host Jingbai pear trees, so as to benefit the pear variety genetic resource conservation and protection.


Assuntos
Bactérias/isolamento & purificação , Pyrus/microbiologia , Actinobacteria/isolamento & purificação , Bactérias/genética , China , Cianobactérias/isolamento & purificação , DNA Ribossômico/química , Endófitos , Microbiota , Proteobactérias/isolamento & purificação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Solo/química , Microbiologia do Solo , Árvores/microbiologia
16.
Genome Biol Evol ; 11(1): 319-334, 2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30534962

RESUMO

Cycads are the only early seed plants that have evolved a specialized root to host endophytic bacteria that fix nitrogen. To provide evolutionary and functional insights into this million-year old symbiosis, we investigate endophytic bacterial sub-communities isolated from coralloid roots of species from Dioon (Zamiaceae) sampled from their natural habitats. We employed a sub-community co-culture experimental strategy to reveal both predominant and rare bacteria, which were characterized using phylogenomics and detailed metabolic annotation. Diazotrophic plant endophytes, including Bradyrhizobium, Burkholderia, Mesorhizobium, Rhizobium, and Nostoc species, dominated the epiphyte-free sub-communities. Draft genomes of six cyanobacteria species were obtained after shotgun metagenomics of selected sub-communities. These data were used for whole-genome inferences that suggest two Dioon-specific monophyletic groups, and a level of specialization characteristic of co-evolved symbiotic relationships. Furthermore, the genomes of these cyanobacteria were found to encode unique biosynthetic gene clusters, predicted to direct the synthesis of specialized metabolites, mainly involving peptides. After combining genome mining with detection of pigment emissions using multiphoton excitation fluorescence microscopy, we also show that Caulobacter species co-exist with cyanobacteria, and may interact with them by means of a novel indigoidine-like specialized metabolite. We provide an unprecedented view of the composition of the cycad coralloid root, including phylogenetic and functional patterns mediated by specialized metabolites that may be important for the evolution of ancient symbiotic adaptations.


Assuntos
Caulobacter/genética , Cianobactérias/genética , Cycadopsida/microbiologia , Fixação de Nitrogênio , Raízes de Plantas/microbiologia , Evolução Biológica , Caulobacter/isolamento & purificação , Caulobacter/metabolismo , Cianobactérias/isolamento & purificação , Cianobactérias/metabolismo , Endófitos , Família Multigênica , Simbiose
17.
Microb Ecol ; 78(2): 482-493, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30535915

RESUMO

Inoculation of soils with cyanobacteria is proposed as a sustainable biotechnological technique for restoration of degraded areas in drylands due to the important role that cyanobacteria and their exopolysaccharides (EPS) play in the environment. So far, few studies have analyzed the macromolecular and chemical characteristics of the polysaccharidic matrix in induced cyanobacterial biocrusts and the scarce existing studies have mainly focused on sandy soil textures. However, the characteristics of the cyanobacterial polysaccharidic matrix may greatly depend on soil type. The objective of this study was to examine the macromolecular distribution and monosaccharidic composition of the polysaccharidic matrix induced by inoculation of two cyanobacterial species common in arid environments, Phormidium ambiguum (non N-fixing) and Scytonema javanicum (N-fixing) in different soil types. S. javanicum promoted a higher release in the soil of the more soluble and less condensed EPS fraction (i.e., the loosely bound EPS fraction, LB-EPS), while P. ambiguum showed a higher release of the less soluble and more condensed EPS fraction (i.e., the tightly bound EPS fraction, TB-EPS). LB-EPSs were mainly composed of low MW molecules (< 50 kDa), while TB-EPSs were mainly composed of high MW molecules (1100-2000 kDa). The two EPS fractions showed a complex monosaccharidic composition (from 11 to 12 different types of monosaccharides), with glucose as the most abundant monosaccharide, in particular in the poorer soils characterized by lower organic C contents. In more C-rich soils, high abundances of galactose, mannose, and xylose were also found. Low abundance of uronic acids and hydrophobic monosaccharides, such as fucose and rhamnose, was found in the EPS extracted from the inoculated soils. Our results point to the influence of soil type on the macromolecular distribution and monosaccharide composition of the polysaccharidic matrix in induced biocrusts, which is likely to affect biocrust development and their role in soil structure and nutrient cycling in restored dryland soils.


Assuntos
Cianobactérias/metabolismo , Polissacarídeos Bacterianos/química , Polissacarídeos Bacterianos/metabolismo , Microbiologia do Solo , Solo/química , Cianobactérias/classificação , Cianobactérias/genética , Cianobactérias/isolamento & purificação , Clima Desértico
18.
Sci Total Environ ; 654: 1379-1388, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30527887

RESUMO

Machu Picchu Inca sanctuary (Cusco Region, Peru) was constructed on a granitic plateau, better known as Vilcabamba batholith. One of the most important carved granitic rocks from this archaeological site is the Sacred Rock, used by Inca citizens for religious rituals. Due to the location and climatic conditions, different rocks from this archaeological site are affected by biocolonizations. Concretely, the Sacred Rock shows flaking and delamination problems. In this work, a non-destructive multi analytical methodology has been applied to determine the possible role of the biodeteriogens, forming the biological patina on the Sacred Rock, in the previously mentioned conservation problems. Before characterizing the biological patina, a mineralogical characterization of the granitic substrate was conducted using X-ray Diffraction, Raman microscopy (RM) and micro energy dispersive X-ray fluorescence spectrometry. For the identification of the main biodeteriogens in the biofilm, Phase Contrast Microscopy was used. RM also allowed to determine the distribution (imaging) and the penetration (depth profiling) of the biogenic pigments present in the biopatina. Thanks to this study, it was possible to asses that some colonizers are growing on inner areas of the rock, reinforcing their possible assistance in the delamination. Moreover, the in-depth distribution of a wide variety of carotenoids in the patinas allowed to approach the penetration ability of the main biodeteriogens and the diffusion of these biogenic pigments to the inner areas of the rocky substrate.


Assuntos
Biofilmes/crescimento & desenvolvimento , Cianobactérias/fisiologia , Líquens/fisiologia , Microalgas/fisiologia , Arqueologia , Cianobactérias/isolamento & purificação , Líquens/isolamento & purificação , Microalgas/isolamento & purificação , Microscopia Óptica não Linear , Peru , Pigmentos Biológicos/classificação , Dióxido de Silício , Espectrometria por Raios X , Análise Espectral Raman , Difração de Raios X
19.
Toxicon ; 157: 18-24, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30448287

RESUMO

The aim of this study was to obtain the first data on the occurrence and distribution of potentially toxic cyanobacteria and cyanotoxins in the Russian Easternmost part of the Gulf of Finland of the Baltic Sea. Studied samples were collected from 2012 to 2017 and three independent approaches - HPLC-HRMS, PCR and light microscopy were applied for cyanotoxins analysis and detection of toxigenic cyanobacteria. Aphanizomenon flos-aquae Ralfs ex Born. et Flah., Planktothrix agardhii (Gom.) Anag. et Kom., Microcystis aeruginosa (Kütz.) Kütz. and Dolichospermum spp. dominated among cyanobacteria in collected samples. In 2012-2013 during research cruises, microcystins concentrations varied from below detection levels to low (0.01-0.6 µg L-1) values. In the autumn of 2015 and 2017, during cyanobacterial bloom events very high concentrations of microcystins (dissolved up to 49 µg L-1, intracellular up to 466 µg g-1) and dissolved anatoxin-a (1.4 µg L-1) were detected. The evaluated toxin profile was represented by most common arginine-containing variants of microcystins (MC-LR, MC-RR, MC-YR) and their desmethylated forms. Leucine-containing congeners (MC-LF; MC-LY; MC-LW for the biomass sample from the coast of Komarovo, 2015) were found at low concentrations. In environmental DNA from bloom samples, we identified mcy genes regions responsible for MC biosynthesis that are specific for Dolichospermum, Microcystis, and Planktothrix. This study is the first molecular evidence the ability of Microcystis aeruginosa and Planktothrix agardhii from the Gulf of Finland to produce microcystins. On the basis of the obtained data of genus-specific PCR and microscopy, we suppose the presence of anatoxin-a-producing Apanizomenon flos-aquae population in the phytoplankton of Russian part of the Gulf of Finland.


Assuntos
Cianobactérias/isolamento & purificação , Microcistinas/análise , Água do Mar/química , Tropanos/análise , Cianobactérias/classificação , Cianobactérias/genética , DNA Bacteriano/análise , Eutrofização , Oceanos e Mares , Federação Russa
20.
Microb Ecol ; 77(2): 288-303, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30019110

RESUMO

Two annual Baltic Sea phytoplankton blooms occur in spring and summer. The bloom intensity is determined by nutrient concentrations in the water, while the period depends on weather conditions. During the course of the bloom, dead cells sink to the sediment where their degradation consumes oxygen to create hypoxic zones (< 2 mg/L dissolved oxygen). These zones prevent the establishment of benthic communities and may result in fish mortality. The aim of the study was to determine how the spring and autumn sediment chemistry and microbial community composition changed due to degradation of diatom or cyanobacterial biomass, respectively. Results from incubation of sediment cores showed some typical anaerobic microbial processes after biomass addition such as a decrease in NO2- + NO3- in the sediment surface (0-1 cm) and iron in the underlying layer (1-2 cm). In addition, an increase in NO2- + NO3- was observed in the overlying benthic water in all amended and control incubations. The combination of NO2- + NO3- diffusion plus nitrification could not account for this increase. Based on 16S rRNA gene sequences, the addition of cyanobacterial biomass during autumn caused a large increase in ferrous iron-oxidizing archaea while diatom biomass amendment during spring caused minor changes in the microbial community. Considering that OTUs sharing lineages with acidophilic microorganisms had a high relative abundance during autumn, it was suggested that specific niches developed in sediment microenvironments. These findings highlight the importance of nitrogen cycling and early microbial community changes in the sediment due to sinking phytoplankton before potential hypoxia occurs.


Assuntos
Bactérias/isolamento & purificação , Cianobactérias/crescimento & desenvolvimento , Diatomáceas/crescimento & desenvolvimento , Sedimentos Geológicos/microbiologia , Fitoplâncton/crescimento & desenvolvimento , Bactérias/classificação , Bactérias/genética , Biomassa , Cianobactérias/classificação , Cianobactérias/genética , Cianobactérias/isolamento & purificação , Diatomáceas/classificação , Diatomáceas/genética , Diatomáceas/isolamento & purificação , Eutrofização , Sedimentos Geológicos/química , Nitratos/análise , Nitratos/metabolismo , Nitritos/análise , Nitritos/metabolismo , Filogenia , Fitoplâncton/classificação , Fitoplâncton/genética , Fitoplâncton/isolamento & purificação , Estações do Ano , Água do Mar/química , Água do Mar/microbiologia
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