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1.
Environ Monit Assess ; 193(5): 294, 2021 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-33893564

RESUMO

Aquatic environments are hotspots for the spread of antibiotic-resistant bacteria and genes due to pollution caused mainly by anthropogenic activities. The aim of this study was to evaluate the impact of wastewater effluents, informal settlements, hospital, and veterinary clinic discharges on the occurrence, antibiotic resistance profile and virulence signatures of Aeromonas spp. and Pseudomonas spp. isolated from surface water and wastewater. High counts of Aeromonas spp. (2.5 (± 0.8) - 3.3 (± 0.4) log10 CFU mL-1) and Pseudomonas spp. (0.6 (± 1.0) - 1.8 (± 1.0) log10 CFU mL-1) were obtained. Polymerase chain reaction (PCR) and MALDI-TOF characterization identified four species of Aeromonas and five of Pseudomonas. The isolates displayed resistance to 3 or more antibiotics (71% of Aeromonas and 94% of Pseudomonas). Aeromonas spp. showed significant association with the antibiotic meropenem (χ2 = 3.993, P < 0.05). The virulence gene aer in Aeromonas was found to be positively associated with the antibiotic resistance gene blaOXA (χ2 = 6.657, P < 0.05) and the antibiotic ceftazidime (χ2 = 7.537, P < 0.05). Aeromonas recovered from both wastewater and surface water displayed high resistance to ampicillin and had higher multiple antibiotic resistance (MAR) indices close to the hospital. Pseudomonas isolates on the other hand exhibited low resistance to carbapenems but very high resistance to the third-generation cephalosporins and cefixime. The results showed that some of the Pseudomonas spp. and Aeromonas spp. isolates were extended-spectrum ß-lactamase producing bacteria. In conclusion, the strong association between virulence genes and antibiotic resistance in the isolates shows the potential health risk to communities through direct and indirect exposure to the water.


Assuntos
Aeromonas , Aeromonas/genética , Antibacterianos/farmacologia , Resistência Microbiana a Medicamentos , Monitoramento Ambiental , Testes de Sensibilidade Microbiana , Pseudomonas/genética , Virulência , Águas Residuárias , Água
2.
Water Sci Technol ; 83(7): 1535-1547, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33843741

RESUMO

The accumulation of toxic chemical constituents in sludge and wastewater has fuelled an interest in investigating efficient and eco-friendly wastewater remediation approaches. In this study, a set of bacterial samples were isolated from petroleum sludge and tested for their ability to degrade different aromatic pollutants, including azo dyes and emerging pollutants. Although exhibiting differential specificity, all bacterial isolates were able to degrade different classes of aromatic dyes efficiently. Ribosomal 16S rRNA sequencing of the 12 bacterial isolates showed that they belonged to two different bacterial genera: Bacillus cereus and Pseudomonas guariconensis. Of these 12 strains, MA1 (B. cereus) was the most promising and was chosen for further optimization and biochemical studies. The optimum culture and remediation conditions for MA1 was found to be at pH 7, with 100 ppm dye concentration, and under aerobic condition. In addition to efficiently degrading various aromatic dyes (e.g. Congo Red, Reactive Black 5, PBS, and Toluidine Blue), MA1 was also found to be capable of degrading various emerging pollutants (e.g. prometryn, fluometuron and sulfamethoxazole). Preliminary transcriptome analysis shows that MA1 grown on media containing a mixture of aromatic dyes appears to differentially express a number of genes. Data shown here strongly suggests that petroleum sludge is a rich reservoir of bacteria with powerful remediation abilities.


Assuntos
Bacillus , Poluentes Ambientais , Petróleo , Bacillus cereus/genética , Biodegradação Ambiental , Pseudomonas , RNA Ribossômico 16S/genética , Esgotos
3.
Artigo em Inglês | MEDLINE | ID: mdl-33835910

RESUMO

A beige-pigmented, oxidase-positive bacterial isolate, Wesi-4T, isolated from charcoal in 2012, was examined in detail by applying a polyphasic taxonomic approach. Cells of the isolates were rod shaped and Gram-stain negative. Examination of the 16S rRNA gene sequence of the isolate revealed highest sequence similarities to the type strains of Pseudomonas matsuisoli and Pseudomonas nosocomialis (both 97.3 %). Phylogenetic analyses on the basis of the 16S rRNA gene sequences indicated a separate position of Wesi-4T, which was confirmed by multilocus sequence analyses (MLSA) based on the three loci gyrB, rpoB and rpoD and a core genome-based phylogenetic tree. Genome sequence based comparison of Wesi-4T and the type strains of P. matsuisoli and P. nosocomialis yielded average nucleotide identity values <95 % and in silico DNA-DNA hybridization values <70 %, respectively. The polyamine pattern contains the major amines putrescine, cadaverine and spermidine. The quinone system contains predominantly ubiquinone Q-9 and in the polar lipid profile diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine are the major lipids. The fatty acid contains predominantly C16 : 0, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and summed feature 8 (C18 : 1ω7c and/or C18 : 1 ω6c). In addition, physiological and biochemical tests revealed a clear phenotypic difference from P. matsuisoli. These cumulative data indicate that the isolate represents a novel species of the genus Pseudomonas for which the name Pseudomonas carbonaria sp. nov. is proposed with Wesi-4T (=DSM 110367T=CIP 111764T=CCM 9017T) as the type strain.


Assuntos
Carvão Vegetal , Filogenia , Pseudomonas/classificação , Alabama , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Genes Bacterianos , Tipagem de Sequências Multilocus , Hibridização de Ácido Nucleico , Fosfolipídeos/química , Pseudomonas/isolamento & purificação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/química
4.
Planta ; 253(4): 78, 2021 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-33715081

RESUMO

MAIN CONCLUSION: The in vitro application of rhizosphere microorganisms led to a higher rooting percentage in Pyrus Py12 rootstocks and increased plant growth of Pyrus Py170 and Prunus RP-20. The rooting of fruit tree rootstocks is the most challenging step of the in vitro propagation process. The use of rhizosphere microorganisms to promote in vitro rooting and plant growth as an alternative to the addition of chemical hormones to culture media is proposed in the present study. Explants from two Pyrus (Py170 and Py12) rootstocks and the Prunus RP-20 rootstock were inoculated with Pseudomonas oryzihabitans PGP01, Cladosporium ramotenellum PGP02 and Phoma sp. PGP03 following two different methods to determine their effects on in vitro rooting and plantlet growth. The effects of the microorganisms on the growth of fully developed Py170 and RP-20 plantlets were also studied in vitro. All experiments were conducted using vermiculite to simulate a soil system in vitro. When applied to Py12 shoots, which is a hard-to-root plant material, both C. ramotenellum PGP02 and Phoma sp. PGP03 fungi were able to increase the rooting percentage from 56.25% to 100% following auxin indole-3-butyric acid (IBA) treatment. Thus, the presence of these microorganisms clearly improved root development, inducing a higher number of roots and causing shorter roots. Better overall growth and improved stem growth of treated plants was observed when auxin treatment was replaced by co-culture with microorganisms. A root growth-promoting effect was observed on RP-20 plantlets after inoculation with C. ramotenellum PGP02, while P. oryzihabitans PGP01 increased root numbers for both Py170 and RP-20 and increased root growth over stem growth for RP-20. It was also shown that the three microorganisms P. oryzihabitans PGP01, C. ramotenellum PGP02 and Phoma sp. PGP03 were able to naturally produce auxin, including indole-3-acetic acid (IAA), at different levels. Overall, our results demonstrate that the microorganisms P. oryzihabitans PGP01 and C. ramotenellum PGP02 had beneficial effects on in vitro rooting and plantlet growth and could be applied to in vitro tissue culture as a substitute for IBA.


Assuntos
Cladosporium/fisiologia , Raízes de Plantas/fisiologia , Prunus/fisiologia , Pseudomonas/fisiologia , Pyrus/fisiologia , /fisiologia , Raízes de Plantas/microbiologia , Prunus/microbiologia , Pyrus/microbiologia , Rizosfera , Microbiologia do Solo
5.
Ann Agric Environ Med ; 28(1): 49-55, 2021 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-33775067

RESUMO

INTRODUCTION AND OBJECTIVE: Ixodes ricinus (I. ricinus) and Dermacentor reticulatus (D. reticulatus) are the most common ticks in Poland. These ticks contain many bacteria, which compose a microbiome with potential impact on humans. The aim of the study was to discover the microbiome of ticks in Poland. MATERIAL AND METHODS: Ticks were collected in The Protected Landscape Area of the Bug and Nurzec Valley, Poland, in 2016-2018 by flagging. They were cleaned in 70% ethanol and damaged in mortar with PBS (without Ca2+ and Mg2+ ions). DNA was extracted from the homogenates with spin columns kits, and used as a matrix in end-point PCR for bacterial 16S rRNA fragments amplifications, and further for next generation sequencing (NGS) by ILLUMINA. RESULTS: In 22 ticks (3 I. ricinus and 19 D. reticulatus) 38 microorganisms were detected. The most common were Francisella hispaniensis and Francisella novicida. In 17 ticks, Sphingomonas oligophenolica, and in 12 Rickettsia aeshlimanii were found. In 2, I. ricinus specific DNA of Borrelia americana and Borrelia carolinensis were found. In one female, D. reticulatus Anaplasma phagocytophilum and Anaplasma centrale were found. Pseudomonas lutea and Ps. moraviensis were detected in 9 and 8 ticks, respectively. CONCLUSIONS: Polish ticks microbiome contains not only well-known tick-borne pathogens, but also other pathogenic microorganisms. For the first time in Poland, Borrelia americana and Borrelia carolinensis in I. ricinus collected from the environment were detected. The dominant pathogenic microorganisms for humans were Francisella spp. and Rickettsia spp., and non-pathogenic - Sphingomonas oligophenolica. Knowledge of a tick microbiome might be useful in tick-borne biocontrol and tick-borne diseases prevention.


Assuntos
Dermacentor/microbiologia , Ixodes/microbiologia , Microbiota , Spirochaetales/genética , Animais , Francisella/classificação , Francisella/genética , Francisella/isolamento & purificação , Genoma Bacteriano , Metagenômica , Polônia , Pseudomonas/classificação , Pseudomonas/isolamento & purificação , Sphingomonas/classificação , Sphingomonas/genética , Sphingomonas/isolamento & purificação , Spirochaetales/classificação , Spirochaetales/isolamento & purificação
6.
J Dairy Sci ; 104(5): 5185-5196, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33663848

RESUMO

Heat-stable endopeptidases in raw milk, especially the alkaline metallopeptidase AprX secreted by Pseudomonas spp., are a well-known challenge for the dairy industry. They can withstand UHT treatment and may cause quality defects over the shelf life of milk products. Therefore, we established an indirect ELISA for the detection of Pseudomonas AprX in milk. We developed a 2-step sample treatment for milk contaminated with AprX to avoid the interference of milk proteins with the detection system. First, casein micelles were destabilized by the detraction of Ca2+ using trisodium citrate; then, AprX was concentrated 10-fold using hydrophobic interaction chromatography. The recovery of AprX in spiked milk samples after the 2-step treatment was 43 ± 0.1%. Specific antibodies for purified AprX from Pseudomonas lactis were produced to establish the ELISA. Western blot experiments showed that the binding affinity of these antibodies depended on the sequence homology of the AprX from P. lactis and several other Pseudomonas spp. The indirect ELISA, which was completed in 6 to 7 h, had a limit of detection of 21.0 ng mL-1 and a limit of quantification of 25.7 ng mL-1. Milk proteins or milk endogenous peptidases were not detected by the antibodies. The ELISA had high precision, with a CV between 0.2 and 0.8% measured on the same day (intraday) and 5.6 and 6.8% measured on 5 separate days (interday). Milk samples were spiked with different AprX activity levels [7.5-150 nkat Na-caseinate/o-phthalaldehyde (OPA) mL-1] and evaluated by ELISA. The recovery of the ELISA was 92.3 ± 1.6 to 105 ± 4.7%. The lowest AprX activity quantifiable in the spiked milk samples was 500 pkat Na-caseinate/OPA mL-1. The proof of concept to detect heat-stable Pseudomonas AprX in milk by ELISA was established.


Assuntos
Endopeptidases , Temperatura Alta , Animais , Ensaio de Imunoadsorção Enzimática/veterinária , Pseudomonas
7.
Science ; 371(6533): 1033-1037, 2021 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-33674490

RESUMO

Microbial production of antibiotics is common, but our understanding of their roles in the environment is limited. In this study, we explore long-standing observations that microbes increase the production of redox-active antibiotics under phosphorus limitation. The availability of phosphorus, a nutrient required by all life on Earth and essential for agriculture, can be controlled by adsorption to and release from iron minerals by means of redox cycling. Using phenazine antibiotic production by pseudomonads as a case study, we show that phenazines are regulated by phosphorus, solubilize phosphorus through reductive dissolution of iron oxides in the lab and field, and increase phosphorus-limited microbial growth. Phenazines are just one of many examples of phosphorus-regulated antibiotics. Our work suggests a widespread but previously unappreciated role for redox-active antibiotics in phosphorus acquisition and cycling.


Assuntos
Antibacterianos/biossíntese , Fenazinas/metabolismo , Fósforo/metabolismo , Pseudomonas/metabolismo , Técnicas de Cultura Celular por Lotes , Disponibilidade Biológica , Oxirredução , Pseudomonas/genética , Pseudomonas/crescimento & desenvolvimento
8.
FEMS Microbiol Ecol ; 97(4)2021 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-33674848

RESUMO

Ralstonia solanacearum biovar2-race3 (Rs r3b2) is an epidemic soil-borne bacterial phytopathogen causing brown rot disease in potato. In this study, we assessed how three soil types stored at the same field site influenced the proportion and diversity of bacterial isolates with in vitro antagonistic activity towards Rs in bulk soil and different potato plant spheres (rhizosphere, endorhiza and endocaulosphere; ecto- and endosphere of seed and yield tubers). In general, the plate counts observed for each sample type were not significantly different. A total of 96 colonies per sample type was picked and screened for in vitro antagonistic activity against Rs. Antagonists were obtained from all bulk soils and plant spheres with the highest proportion obtained from the endorhiza and endocaulosphere of potato plants. BOX-PCR fingerprints of antagonists showed that some were specific for particular plant spheres independent of the soil type, while others originated from different plant spheres of a particular soil type. The majority of antagonists belonged to Pseudomonas. A high proportion of antagonists produced siderophores, and interestingly antagonists from potato tubers frequently carried multiple antibiotic production genes. Our data showed an enrichment of bacteria with genes or traits potentially involved in biocontrol in the rhizosphere and in endophytic compartments. We report that the proportion and diversity of in vitro antagonists towards Rs isolated from bulk soil and different spheres of potato plants grown under field conditions in three different soil types was mainly shaped by the plant sphere and to a lesser extent by the soil type. Bacteria with antagonistic activity towards Ralstonia solanacearum were isolated from all plant spheres and bulk soils but their proportion was highest in endophytic compartments.


Assuntos
Ralstonia solanacearum , Solanum tuberosum , Doenças das Plantas , Pseudomonas , Solo
9.
Molecules ; 26(4)2021 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-33672940

RESUMO

Pseudomonas is considered as the specific spoilage bacteria in meat and meat products. The purpose of this study was to evaluate the inactivation efficiency and mechanisms of slightly acidic electrolyzed water (SAEW) against Pseudomonas deceptionensis CM2, a strain isolated from spoiling chicken breast. SAEW caused time-dependent inactivation of P. deceptionensis CM2 cells. After exposure to SAEW (pH 5.9, oxidation-reduction potential of 945 mV, and 64 mg/L of available chlorine concentration) for 60 s, the bacterial populations were reduced by 5.14 log reduction from the initial load of 10.2 log10 CFU/mL. Morphological changes in P. deceptionensis CM2 cells were clearly observed through field emission-scanning electron microscopy as a consequence of SAEW treatment. SAEW treatment also resulted in significant increases in the extracellular proteins and nucleic acids, and the fluorescence intensities of propidium iodide and n-phenyl-1-napthylamine in P. deceptionensis CM2 cells, suggesting the disruption of cytoplasmic and outer membrane integrity. These findings show that SAEW is a promising antimicrobial agent.


Assuntos
Ácidos/farmacologia , Membrana Celular/patologia , Eletrólise , Viabilidade Microbiana/efeitos dos fármacos , Pseudomonas/efeitos dos fármacos , Água/farmacologia , Membrana Celular/efeitos dos fármacos , Membrana Celular/ultraestrutura , Permeabilidade da Membrana Celular/efeitos dos fármacos , Citoplasma/efeitos dos fármacos , Desinfecção , Pseudomonas/citologia , Pseudomonas/ultraestrutura
10.
Pestic Biochem Physiol ; 173: 104777, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33771256

RESUMO

Ceratocystis fimbriata is the pathogen of black rot disease, which widely exists in sweet potato producing areas all over the world. The antifungal activity of volatile organic compounds (VOCs) released by Pseudomonas chlororaphis subsp. aureofaciens SPS-41 against C. fimbriata was reported in our previous study. In this study, we attempted to reveal the underlying antifungal mechanism of SPS-41 volatiles. Our results showed that the VOCs released by SPS-41 caused the morphological change of hyphae, destroyed the integrity of cell membrane, reduced the content of ergosterol, and induced massive accumulation of reactive oxygen species in C. fimbriata cells. Furthermore, SPS-41 fumigation decreased the mitochondrial membrane potential, acetyl-CoA and pyruvate content of C. fimbriata cells, as well as the mitochondrial dehydrogenases activity. In addition, the VOCs generated by SPS-41 reduced the intracellular ATP content and increased the extracellular ATP content of C. fimbriata. In summary, SPS-41 fumigation exerted its antifungal activity by inducing oxidative stress and mitochondrial dysfunction in C. fimbriata.


Assuntos
Ascomicetos , Compostos Orgânicos Voláteis , Antifúngicos/farmacologia , Mitocôndrias , Estresse Oxidativo , Doenças das Plantas , Pseudomonas , Compostos Orgânicos Voláteis/farmacologia
11.
Appl Environ Microbiol ; 87(9)2021 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-33579686

RESUMO

Although enzyme-encoding genes involved in the degradation of carbaryl have been reported in Pseudomonas sp. strain XWY-1, no regulator has been identified yet. In the mcbABCDEF cluster responsible for the upstream pathway of carbaryl degradation (from carbaryl to salicylate), the mcbA gene is constitutively expressed, while mcbBCDEF is induced by 1-naphthol, the hydrolysis product of carbaryl by McbA. In this study, we identified McbG, a transcriptional activator of the mcbBCDEF cluster. McbG is a 315-amino-acid protein with a molecular mass of 35.7 kDa. It belongs to the LysR family of transcriptional regulators and shows 28.48% identity to the pentachlorophenol (PCP) degradation transcriptional activation protein PcpR from Sphingobium chlorophenolicum ATCC 39723. Gene disruption and complementation studies reveal that mcbG is essential for transcription of the mcbBCDEF cluster in response to 1-naphthol in strain XWY-1. The results of the electrophoretic mobility shift assay (EMSA) and DNase I footprinting show that McbG binds to the 25-bp motif in the mcbBCDEF promoter area. The palindromic sequence TATCGATA within the motif is essential for McbG binding. The binding site is located between the -10 box and the transcription start site. In addition, McbG can repress its own transcription. The EMSA results show that a 25-bp motif in the mcbG promoter area plays an important role in McbG binding to the promoter of mcbG This study reveals the regulatory mechanism for the upstream pathway of carbaryl degradation in strain XWY-1. The identification of McbG increases the variety of regulatory models within the LysR family of transcriptional regulators.IMPORTANCE Pseudomonas sp. strain XWY-1 is a carbaryl-degrading strain that utilizes carbaryl as the sole carbon and energy source for growth. The functional genes involved in the degradation of carbaryl have already been reported. However, the regulatory mechanism has not been investigated yet. Previous studies demonstrated that the mcbA gene, responsible for hydrolysis of carbaryl to 1-naphthol, is constitutively expressed in strain XWY-1. In this study, we identified a LysR-type transcriptional regulator, McbG, which activates the mcbBCDEF gene cluster responsible for the degradation of 1-naphthol to salicylate and represses its own transcription. The DNA binding site of McbG in the mcbBCDEF promoter area contains a palindromic sequence, which affects the binding of McbG to DNA. These findings enhance our understanding of the mechanism of microbial degradation of carbaryl.


Assuntos
Proteínas de Bactérias/genética , Carbaril/metabolismo , Pseudomonas/genética , Pseudomonas/metabolismo , Fatores de Transcrição/genética , Proteínas de Bactérias/metabolismo , Biodegradação Ambiental , Família Multigênica , Fatores de Transcrição/metabolismo
12.
Appl Environ Microbiol ; 87(9)2021 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-33608298

RESUMO

Biosurfactant production is a common trait in leaf surface-colonizing bacteria that has been associated with increased survival and movement on leaves. At the same time, the ability to degrade aliphatics is common in biosurfactant-producing leaf colonizers. Pseudomonads are common leaf colonizers and have been recognized for their ability to produce biosurfactants and degrade aliphatic compounds. In this study, we investigated the role of biosurfactants in four non-plant-pathogenic Pseudomonas strains by performing a series of experiments to characterize their surfactant properties and their role during leaf colonization and diesel degradation. The biosurfactants produced were identified using mass spectrometry. Two strains produced viscosin-like biosurfactants, and the other two produced massetolide A-like biosurfactants, which aligned with the phylogenetic relatedness between the strains. To further investigate the role of surfactant production, random Tn5 transposon mutagenesis was performed to generate knockout mutants. The knockout mutants were compared to their respective wild types with regard to their ability to colonize gnotobiotic Arabidopsis thaliana and to degrade diesel or dodecane. It was not possible to detect negative effects during plant colonization in direct competition or individual colonization experiments. When grown on diesel, knockout mutants grew significantly slower than their respective wild types. When grown on dodecane, knockout mutants were less impacted than during growth on diesel. By adding isolated wild-type biosurfactants, it was possible to complement the growth of the knockout mutants.IMPORTANCE Many leaf-colonizing bacteria produce surfactants and are able to degrade aliphatic compounds; however, whether surfactant production provides a competitive advantage during leaf colonization is unclear. Furthermore, it is unclear if leaf colonizers take advantage of the aliphatic compounds that constitute the leaf cuticle and cuticular waxes. Here, we tested the effect of surfactant production on leaf colonization, and we demonstrate that the lack of surfactant production decreases the ability to degrade aliphatic compounds. This indicates that leaf surface-dwelling, surfactant-producing bacteria contribute to degradation of environmental hydrocarbons and may be able to utilize leaf surface waxes. This has implications for plant-microbe interactions and future studies.


Assuntos
Arabidopsis/microbiologia , Gasolina , Folhas de Planta/microbiologia , Pseudomonas/metabolismo , Tensoativos/metabolismo , Alcanos/metabolismo , Biodegradação Ambiental , Mutagênese , Filogenia , Pseudomonas/genética , Pseudomonas/crescimento & desenvolvimento , RNA Ribossômico 16S , Tensoativos/química
13.
Appl Environ Microbiol ; 87(9)2021 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-33608299

RESUMO

Gram-negative bacteria employ secretion systems to translocate proteinaceous effectors from the cytoplasm to the extracellular milieu, thus interacting with the surrounding environment or microniche. It is known that bacteria can benefit from the type VI secretion system (T6SS) by transporting ions to combat reactive oxygen species (ROS). Here, we report that T6SS activities conferred tolerance to nicotine-induced oxidative stress in Pseudomonas sp. strain JY-Q, a highly active nicotine degradation strain isolated from tobacco waste extract. AA098_13375 was identified to encode a dual-functional effector with antimicrobial and anti-ROS activities. Wild-type strain JY-Q grew better than the AA098_13375 deletion mutant in nicotine-containing medium by antagonizing increased intracellular ROS levels. It was, therefore, tentatively designated TseN (type VI secretion system effector for nicotine tolerance), homologs of which were observed to be broadly ubiquitous in Pseudomonas species. TseN was identified as a Tse6-like bacteriostatic toxin via monitoring intracellular NAD+ TseN presented potential antagonism against ROS to fine tune the heavy traffic of nicotine metabolism in strain JY-Q. It is feasible that the dynamic tuning of NAD+ driven by TseN could satisfy demands from nicotine degradation with less cytotoxicity. In this scenario, T6SS involves a fascinating accommodation cascade that prompts constitutive biotransformation of N-heterocyclic aromatics by improving bacterial robustness/growth. In summary, the T6SS in JY-Q mediated resistance to oxidative stress and promoted bacterial fitness via a contact-independent growth competitive advantage, in addition to the well-studied T6SS-dependent antimicrobial activities.IMPORTANCE Mixtures of various pollutants and the coexistence of numerous species of organisms are usually found in adverse environments. Concerning biodegradation of nitrogen-heterocyclic contaminants, the scientific community has commonly focused on screening functional enzymes that transform pollutants into intermediates of attenuated toxicity or for primary metabolism. Here, we identified dual roles of the T6SS effector TseN in Pseudomonas sp. strain JY-Q, which is capable of degrading nicotine. The T6SS in strain JY-Q is able to deliver TseN to kill competitors and provide a growth advantage by a contact-independent pattern. TseN could monitor the intracellular NAD+ level by its hydrolase activity, causing cytotoxicity in competitive rivals but metabolic homeostasis on JY-Q. Moreover, JY-Q could be protected from TseN toxicity by the immunity protein TsiN. In conclusion, we found that TseN with cytotoxicity to bacterial competitors facilitated the nicotine tolerance of JY-Q. We therefore reveal a working model between T6SS and nicotine metabolism. This finding indicates that multiple diversified weapons have been evolved by bacteria for their growth and robustness.


Assuntos
Proteínas de Bactérias/metabolismo , Nicotina/metabolismo , Pseudomonas/metabolismo , Sistemas de Secreção Tipo VI/metabolismo , Proteínas de Bactérias/genética , Biodegradação Ambiental , Homeostase , Família Multigênica , Pseudomonas/genética , Espécies Reativas de Oxigênio/metabolismo , Sistemas de Secreção Tipo VI/genética
14.
Bioresour Technol ; 328: 124826, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33631461

RESUMO

Fluoroquinolone antibiotics like ofloxacin (OFL) have been frequently detected in the aquatic environment. Recently manganese-oxidizing bacteria (MOB) have attracted research efforts on the degradation of recalcitrant pollutants with the aid of their biogenic manganese oxides (BioMnOx). Herein, the degradation of OFL with a strain of MOB (Pseudomonas sp. F2) was investigated for the first time. It was found that the bacteria can degrade up to 100% of 5 µg/L OFL. BioMnOx and Mn(III) intermediates significantly contributed to the degradation. Moreover, the degradation was clearly declined when the microbial activity was inactivated by heat or ethanol, indicating the importance of bioactivity. Possible transformation products of OFL were identified by HPLC-MS and the degradation pathway was proposed. In addition, the toxicity of OFL was reduced by 66% after the degradation.


Assuntos
Manganês , Pseudomonas , Bactérias , Compostos de Manganês , Ofloxacino , Oxirredução , Óxidos
15.
Int J Mol Sci ; 22(4)2021 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-33557119

RESUMO

Coumarins are well known secondary metabolites widely found in various plants. However, the degradation of these compounds in the environment has not been studied in detail, and, especially, the initial stages of the catabolic pathways of coumarins are not fully understood. A soil isolate Pseudomonas mandelii 7HK4 is able to degrade 7-hydroxycoumarin (umbelliferone) via the formation of 3-(2,4-dihydroxyphenyl)propionic acid, but the enzymes catalyzing the α-pyrone ring transformations have not been characterized. To elucidate an upper pathway of the catabolism of 7-hydroxycoumarin, 7-hydroxycoumarin-inducible genes hcdD, hcdE, hcdF, and hcdG were identified by RT-qPCR analysis. The DNA fragment encoding a putative alcohol dehydrogenase HcdE was cloned, and the recombinant protein catalyzed the NADPH-dependent reduction of 7-hydroxycoumarin both in vivo and in vitro. The reaction product was isolated and characterized as a 7-hydroxy-3,4-dihydrocoumarin based on HPLC-MS and NMR analyses. In addition, the HcdE was active towards 6,7-dihydroxycoumarin, 6-hydroxycoumarin, 6-methylcoumarin and coumarin. Thus, in contrast to the well-known fact that the ene-reductases usually participate in the reduction of the double bond, an alcohol dehydrogenase catalyzing such reaction has been identified, and, for P. mandelii 7HK4, 7-hydroxycoumarin degradation via a 7-hydroxy-3,4-dihydrocoumarin pathway has been proposed.


Assuntos
Álcool Desidrogenase/metabolismo , Biodegradação Ambiental , Pseudomonas/metabolismo , Umbeliferonas/metabolismo , Álcool Desidrogenase/genética , Catálise , Cumarínicos/farmacologia , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Genoma Bacteriano , Estrutura Molecular , Família Multigênica , NADP/metabolismo , Oxirredutases/genética , Oxirredutases/metabolismo , Filogenia , Pseudomonas/classificação , Pseudomonas/enzimologia , Pseudomonas/genética , Reação em Cadeia da Polimerase em Tempo Real , Umbeliferonas/química
16.
J Environ Manage ; 284: 112030, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33529882

RESUMO

This study prioritizes the biodegradation potential of novel bacterial consortia formulated from cow dung samples towards low-density polyethylene (LDPE) and polypropylene (PP) in comparison with our previous studies. Ten possible consortia were formulated using 10 selected isolates with >10% weight reduction of LDPE and PP, these were pre-treated under UV for 1 h, and their biodegradation potential was studied for 160 days. The isolates present in prioritized consortia were characterized by standard microbiology and 16SrRNA gene sequencing methods. Out of 10 bacterial consortia formulated, potential consortium-CB3 showed greater percentage degradation (weight reduction) of 64.25 ± 2% and 63.00 ± 2% towards LDPE and PP films, respectively (p < 0.05) at 37 °C compared to other consortia. Significant structural variations due to the formation of bacterial biofilm were observed in CB3 treated LDPE and PP films. The three bacteria-IS1, IS2, and IS3-that constituted CB3 were found to be novel strains and designated to be Enterobacter sp nov. bt DSCE01, Enterobacter cloacae nov. bt DSCE02, and Pseudomonas aeruginosa nov. bt DSCE-CD03, respectively. This novel consortium can be scaled up for enhanced degradation of plastic polymers and probably design cost-effective bio-digester for industrial applications using CB3 as potential inoculum.


Assuntos
Polietileno , Polipropilenos , Animais , Biodegradação Ambiental , Bovinos , Enterobacter , Feminino , Pseudomonas/genética
17.
Environ Pollut ; 274: 116572, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33529904

RESUMO

Due to ecologically unsustainable mining strategies, there remain large areas of phosphate mining wasteland contaminated with accumulated lead (Pb). In this study, a Pb-resistant phosphate-solubilizing strain of Pseudomonas sp., LA, isolated from phosphate mining wasteland, was coupled with two species of native plants, ryegrass (Lolium perenne L.) and sonchus (Sonchus oleraceus L.), for use in enhancing the reduction of bioavailable Pb in soil from a phosphate mining wasteland. The effect of PbCO3 solubilization by Pseudomonas sp. strain LA was evaluated in solution culture. It was found that strain LA could attain the best solubilization effect on insoluble Pb when the PbCO3 concentration was 1% (w/v). Pot experiments were carried out to investigate the potential of remediation by ryegrass and sonchus in phosphate mining wastelands with phosphate rock application and phosphate-solubilizing bacteria inoculation. Compared to the control group without strain LA inoculation, the biomass and length of ryegrass and sonchus were markedly increased, available P and Pb in roots increased by 22.2%-325% and 23.3%-368%, respectively, and available P and Pb in above-ground parts increased by 4.44%-388% and 1.67%-303%, respectively, whereas available Pb in soil decreased by 14.1%-27.3%. These results suggest that the combination of strain LA and plants is a bioremediation strategy with considerable potential and could help solve the Pb-contamination problem in phosphate mining wastelands.


Assuntos
Lolium , Poluentes do Solo , Sonchus , Biodegradação Ambiental , Disponibilidade Biológica , Mineração , Fosfatos , Pseudomonas , Solo , Poluentes do Solo/análise
18.
Bioresour Technol ; 329: 124867, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33640696

RESUMO

Pseudomonas asiatica C1, which could grow on glucose and aerobically synthesize coenzyme B12, was isolated and developed as a microbial cell factory for the production of 3-hydroxypropionic acid (3-HP) from glycerol. Three heterologous enzymes, glycerol dehydratase (GDHt), GDHt reactivase (GdrAB) and aldehyde dehydrogenase (ALDH), constituting the 3-HP synthesis pathway, were introduced, and three putative dehydrogenases, responsible for 3-HP degradation, were disrupted. In addition, the transcriptional repressor glpR and the glycerol kinase glpK were removed to increase glycerol import while eliminating the catabolic use of glycerol. Furthermore, the global regulatory protein encoded by crc and several putative oxidoreductases (PDORs) were disrupted. One resulting strain, when grown on glucose, could produce 3-HP at ~ 700 mM in 48 h in a fed-batch bioreactor experiment, with the molar yield > 0.99 on glycerol without much by-products. This study demonstrates that P. asiatica C1 is a promising host for production of 3-HP from glycerol.


Assuntos
Glicerol , Pseudomonas , Ácido Láctico/análogos & derivados
19.
Bioresour Technol ; 326: 124794, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33550210

RESUMO

For solving the challenge in nitrate removal from low C/N wastewater at low temperature, Pseudomonas sp. Y39-6 was isolated and used in nitrate removal. It showed aerobic-heterotrophic denitrification with rate of 1.77 ± 0.31 mg/L·h and unusual aerobic-autotrophic nitrate removal (rate of 0.324 mg/L·h). The aerobic-autotrophic nitrate removal mechanisms were deep investigated by analyzing the nitrate removal process and genomic information. At aerobic-autotrophic condition, the strain Y39-6 could assimilate nitrate to amino acid (NO3- + PHA + CO2 â†’ C5H7O2N) with the carbon source from Polyhydroxyalkanoic acid (PHA) degradation and CO2 fixation. Flagella motivation, swarming activity and extracellular polymeric substances (EPS) production regulated Pseudomonas sp. Y39-6 forming biofilm. Carriers immobilized with Pseudomonas sp. Y39-6 were used in moving bed biofilm reactor (MBBR) and achieved 24.83% nitrate removal at C/N < 1 and 4 °C. Results of this study provided a practical way for nitrogen removal from low C/N wastewater in cold region.


Assuntos
Nitratos , Águas Residuárias , Biofilmes , Reatores Biológicos , Desnitrificação , Nitrogênio , Pseudomonas , Temperatura
20.
Bioresour Technol ; 323: 124601, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33385627

RESUMO

The present study revealed biosurfactants production by a novel oil-degrading Pseudomonas sp. S2WE isolated from hydrocarbon enriched water sample, where the genus Pseudomonas (48.65%) was dominated amongst several other genera. Biosurfactants produced by this strain showed the great potential for surface tension reduction (SFT) and emulsification. The extracted crude biosurfactants were characterized using ultra-high-performance liquid chromatography-Mass Spectrometry (UHPLC-MS) and identified various mono-and di-rhamnolipids homologs from the mixture. Moreover, the lowest SFT 33.05 ± 0.1 mN/m and highest emulsification of 60.65 ± 0.64% were achieved from rhamnolipids produced from glycerol with urea. Compared to initial screening, almost (>87%) higher emulsification was observed. In addition, the biosurfactants were found highly stable at different environmental factors i.e. temperature (4 °C-121 °C), pH (3-10) and NaCl conc. (1-9%). The high stable rhamnolipids produced by new Pseudomonas sp. S2WE in this study could widely be used in enormous industrial as well as environmental applications.


Assuntos
Bioprospecção , Lagos , Glicolipídeos , Pseudomonas , Pseudomonas aeruginosa , Tensoativos
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