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1.
Electron. j. biotechnol ; 44: 14-18, Mar. 2020. ilus, graf
Artigo em Inglês | LILACS | ID: biblio-1087629

RESUMO

BACKGROUND: Although bioactive metabolites capable of causing oxidative photo-necrosis in plant tissues have been identified in fungi, little is known about this type of mechanism in bacteria. These metabolites act as photosensitizers that generate reactive oxygen species (ROS) capable of causing damage to cells. In addition, these metabolites can pass into an energetically excited state when they receive some luminous stimulus, a condition in which they interact with other molecules present in the environment, such as molecular oxygen (O2), also known as triplet oxygen (3 O2), generating ROS. RESULTS: The suspension of the bacterial culture of Pseudomonas cedrina was shown to produce foliar necrosis in papaya leaves (Carica papaya L.) only in the presence of sunlight, which is evidence of photosensitizing mechanisms that generate singlet oxygen (1 O2). From the chemical study of extracts obtained from this bacteria, 3-(4-(2-carboxipropyl) phenyl) but-2-enoic acid (1) was isolated. This compound, in the presence of light and triplet oxygen (3 O2), was able to oxidize ergosterol to its peroxide, since it acted as a photosensitizer producing 1 O2, with which it was corroborated that a photosensitization reaction occurs, mechanism by which this bacterium could prove to cause oxidative foliar photo-necrosis. CONCLUSIONS: P. cedrina was able to induce oxidative foliar photo-necrosis because of its potential ability to produce photosensitizing metabolites that generate singlet oxygen in the plants it colonizes. Based on the above, it can be proposed that some bacteria can cause oxidative foliar photo-necrosis as an important mechanism in the pathogenesis of host species.


Assuntos
Doenças das Plantas/microbiologia , Pseudomonas/fisiologia , Carica/microbiologia , Oxigênio Singlete/metabolismo , Pseudomonas/metabolismo , Ácidos , Espécies Reativas de Oxigênio , Folhas de Planta/microbiologia , Foto-Oxidação , Luz , Necrose
2.
J Med Microbiol ; 69(3): 347-360, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31976855

RESUMO

Pseudomonas brassicacearum is one of over fifty species of bacteria classified into the P. fluorescens group. Generally considered a harmless commensal, these bacteria are studied for their plant-growth promotion (PGP) and biocontrol characteristics. Intriguingly, P. brassicacearum is closely related to P. corrugata, which is classified as an opportunistic phytopathogen. Twenty-one P. brassicacearum genomes have been sequenced to date. In the current review, genomes of P. brassicacearum and strains from the P. corrugata clade were mined for regions associated with PGP, biocontrol and pathogenicity. We discovered that 'beneficial' bacteria and those classified as plant pathogens have many genes in common; thus, only a fine line separates beneficial/harmless commensals from those capable of causing disease in plants. The genotype and physiological state of the plant, the presence of biotic/abiotic stressors, and the ability of bacteria to manipulate the plant immune system collectively contribute to how the bacterial-plant interaction plays out. Because production of extracellular metabolites is energetically costly, these compounds are expected to impart a fitness advantage to the producer. P. brassicacearum is able to reduce the threat of nematode predation through release of metabolites involved in biocontrol. Moreover this bacterium has the unique ability to form biofilms on the head of Caenorhabditis elegans, as a second mechanism of predator avoidance. Rhizobacteria, plants, fungi, and microfaunal predators have occupied a shared niche for millions of years and, in many ways, they function as a single organism. Accordingly, it is essential that we appreciate the dynamic interplay among these members of the community.


Assuntos
Biofilmes/crescimento & desenvolvimento , Caenorhabditis elegans/microbiologia , Genoma Bacteriano/genética , Doenças das Plantas/microbiologia , Plantas/microbiologia , Pseudomonas/fisiologia , Animais , Lipopeptídeos/genética , Controle Biológico de Vetores , Pseudomonas/genética , Pseudomonas/crescimento & desenvolvimento , Transdução de Sinais , Simbiose
3.
J Sci Food Agric ; 100(3): 1092-1098, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31667839

RESUMO

BACKGROUND: Plant-growth-promoting rhizobacteria (PGPR) and arbuscular mycorrhizal (AM) fungi have the ability to enhance the growth, fitness, and quality of various agricultural crops, including cowpea. However, field trials confirming the benefits of microbes in large-scale applications using economically viable and efficient inoculation methods are still scarce. Microbial seed coating has a great potential for large-scale agriculture through the application of reduced amounts of PGPR and AM fungi inocula. Thus, in this study, the impact of seed coating with PGPR, Pseudomonas libanensis TR1 and AM fungus, Rhizophagus irregularis (single or multiple isolates) on grain yield and nutrient content of cowpea under low-input field conditions was evaluated. RESULTS: Seed coating with P. libanensis + multiple isolates of R. irregularis (coatPMR) resulted in significant increases in shoot dry weight (76%), and in the number of pods and seeds per plant (52% and 56%, respectively) and grain yield (56%), when compared with non-inoculated control plants. However, seed coating with P. libanensis + R. irregularis single-isolate (coatPR) did not influence cowpea grain yield. Grain lipid content was significantly higher (25%) in coatPMR plants in comparison with control. Higher soil organic matter and lower pH were observed in the coatPMR treatment. CONCLUSIONS: Our findings indicate that cowpea field productivity can be improved by seed coating with PGPR and multiple AM fungal isolates under low-input agricultural systems. © 2019 Society of Chemical Industry.


Assuntos
Produção Agrícola/métodos , Glomeromycota/fisiologia , Pseudomonas/fisiologia , Sementes/microbiologia , Vigna/crescimento & desenvolvimento , Micorrizas/fisiologia , Sementes/crescimento & desenvolvimento , Solo/química , Vigna/microbiologia
4.
Microbiol Res ; 232: 126388, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31865223

RESUMO

Induction of systemic tolerance in sorghum [Sorghum bicolor (L.) Moench] against drought stress was studied by screening a large collection of rhizobacterial isolates for their potential to exhibit this essential plant growth-promoting trait. This was done by means of a greenhouse assay that measured the relative change in both plant height and -biomass (roots and shoots) between rhizobacteria-primed versus non-primed (naïve) plants under drought stress conditions. In order to elucidate the metabolomic changes in S. bicolor that conferred the drought stress tolerance after treatment (priming) with selected isolates, untargeted ultra-high performance liquid chromatography-high definition mass spectrometry (UHPLC-HDMS)-based metabolomics was carried out. Intracellular metabolites were methanol-extracted from rhizobacteria-primed and naïve S. bicolor roots and shoots. Extracts were analysed on a UHPLC-HDMS system and the generated data were chemometrically mined to determine signatory metabolic profiles and bio-markers related to induced systemic tolerance. The metabolomic results showed significant treatment-related differential metabolic reprogramming between rhizobacteria-primed and naïve plants, correlating to the ability of the selected isolates to protect S. bicolor against drought stress. The selected isolates, identified by means of 16S rRNA gene sequencing as members of the genera Bacillus and Pseudomonas, were screened for 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity by means of an in vitro assay and the presence of the acdS gene was subsequently confirmed by PCR for strain N66 (Pseudomonas sp.). The underlying key metabolic changes in the enhanced drought stress tolerance observed in rhizobacteria-primed S. bicolor plants included (1) augmented antioxidant capacity; (2) growth promotion and root architecture modification as a result of the upregulation of the hormones gibberellic acid, indole acetic acid and cytokinin; (3) the early activation of induce systemic tolerance through the signalling hormones brassinolides, salicylic acid and jasmonic acid and signalling molecules sphingosine and psychosine; (4) the production of the osmolytes proline, glutamic acid and choline; (5) the production of the epicuticular wax docosanoic acid and (6) ACC deaminase activity resulting in lowered ethylene levels. These results unravelled key molecular details underlying the PGPR-induced systemic tolerance in sorghum plants, providing insights for the plant priming for abiotic stress.


Assuntos
Adaptação Fisiológica , Secas , Desenvolvimento Vegetal , Rhizobiaceae/fisiologia , Sorghum/microbiologia , Sorghum/fisiologia , Bacillus/isolamento & purificação , Bacillus/fisiologia , Biomassa , Raízes de Plantas/microbiologia , Pseudomonas/isolamento & purificação , Pseudomonas/fisiologia , RNA Ribossômico 16S , Rhizobiaceae/isolamento & purificação , Rhizobium , Solo/química , Microbiologia do Solo , Estresse Fisiológico
5.
PLoS One ; 14(12): e0226155, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31860658

RESUMO

Exploration of diverse environmental samples for plant growth-promoting microbes to fulfill the increasing demand for sustainable agriculture resulted in increased use of bacterial biofertilizer. We aimed for the isolation of plant growth-promoting as well as antibiotic sensitive bacteria from bovine manure samples. The basic theme of our study is to highlight potentials of bacteria in manure and the unchecked risk associated with the application of manure i.e. introducing antibiotic-resistant microbial flora, as fertilizer. Fifty-two, morphologically distinct isolates; from eight different manure samples, were subjected to plant growth-promoting parametric tests along with antibiotic resistance. Thirteen antibiotic sensitive bacterial strains with potentials of plant growth promotion further characterized by 16S rRNA ribotyping and the identified genera were Stenotrophomonas, Achromobacter, Pseudomonas, and Brevibacillus. Successful radish seeds germination under sterile in-vitro conditions showed the potential of selected bacterial isolates as plant growth-promoting bacteria. The results of this study confirmed plant growth-promoting characteristics of bovine manures' bacterial strains along with an alarming antibiotic resistance load which comprises 75% of bacterial isolated population. Our study showed distinct results of un-explored manure bacterial isolates for plant growth promotion and flagged ways associated with unchecked manure application in agriculture soil through high load of antibiotic resistant bacteria.


Assuntos
Bactérias/classificação , Esterco/microbiologia , RNA Ribossômico 16S/genética , Raphanus/crescimento & desenvolvimento , Achromobacter/classificação , Achromobacter/isolamento & purificação , Achromobacter/fisiologia , Agricultura/métodos , Animais , Bactérias/genética , Bactérias/isolamento & purificação , Brevibacillus/classificação , Brevibacillus/isolamento & purificação , Brevibacillus/fisiologia , Bovinos , Fertilizantes , Germinação , Testes de Sensibilidade Microbiana , Pseudomonas/classificação , Pseudomonas/isolamento & purificação , Pseudomonas/fisiologia , Raphanus/microbiologia , Microbiologia do Solo , Stenotrophomonas/classificação , Stenotrophomonas/isolamento & purificação , Stenotrophomonas/fisiologia
6.
Chem Commun (Camb) ; 55(100): 15020-15032, 2019 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-31782426

RESUMO

With the rapid spread of resistance among parasites and bacterial pathogens, antibiotic-resistant infections have drawn much attention worldwide. Consequently, there is an urgent need to develop new strategies to treat neglected diseases and drug-resistant infections. Here, we outline several new strategies that have been developed to counter pathogenic microorganisms by designing and constructing antimicrobial peptides (AMPs). In addition to traditional discovery and design mechanisms guided by chemical biology, synthetic biology and computationally-based approaches offer useful tools for the discovery and generation of bioactive peptides. We believe that the convergence of such fields, coupled with systematic experimentation in animal models, will help translate biological peptides into the clinic. The future of anti-infective therapeutics is headed towards specifically designed molecules whose form is driven by computer-based frameworks. These molecules are selective, stable, and active at therapeutic doses.


Assuntos
Anti-Infecciosos/uso terapêutico , Peptídeos Catiônicos Antimicrobianos/química , Doenças Transmissíveis/tratamento farmacológico , Algoritmos , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Peptídeos Catiônicos Antimicrobianos/genética , Peptídeos Catiônicos Antimicrobianos/uso terapêutico , Biofilmes/efeitos dos fármacos , Doenças Transmissíveis/patologia , Desenho de Fármacos , Humanos , Imunidade Inata/efeitos dos fármacos , Fatores Imunológicos/química , Fatores Imunológicos/farmacologia , Fatores Imunológicos/uso terapêutico , Engenharia de Proteínas , Pseudomonas/fisiologia
7.
J Photochem Photobiol B ; 200: 111655, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31655456

RESUMO

Textile effluent is often difficult to manage as it contains a high concentration of toxic and recalcitrant synthetic dyes. In this study, congo Red and textile effluent were treated by electrochemical oxidation using RuO2-IrO2 coated titanium electrode as an anode followed by biodecolorization using Pseudomonas stutzeri MN1 and Acinetobacter baumannii MN3. Effluent pre-treatment is often necessary to minimize the inhibitory effects of textile dyes on dye degrading bacterial during bio-treatment. The pre-treatment of Congo Red by electrochemical oxidation for 10 min resulted in a decolorization rate of 98% at a pH, NaCl concentration, and current density of 7, 2 g L-1, and 20 mA cm-2. Subsequent bio-treatment of the pretreated Congo Red enhanced the biodegradation to 93%. The COD removal efficiency in real textile effluent following electrochemical pretreatment and biological treatment using bacterial consortium were 3.8% and 93%, respectively. Therefore, integrating electrochemical oxidation and microbial consortia offers an effective and environmentally friendly approach for treating complex industrial effluents.


Assuntos
Biodegradação Ambiental , Vermelho Congo/química , Técnicas Eletroquímicas/métodos , Têxteis , Poluentes Químicos da Água/química , Acinetobacter/fisiologia , Compostos Azo/química , Vermelho Congo/metabolismo , Eletrodos , Concentração de Íons de Hidrogênio , Irídio/química , Oxirredução , Pseudomonas/fisiologia , Compostos de Rutênio/química , Cloreto de Sódio/química , Titânio/química , Eliminação de Resíduos Líquidos , Poluentes Químicos da Água/metabolismo
8.
Environ Sci Pollut Res Int ; 26(31): 31822-31833, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31487012

RESUMO

Remediation of heavy metal-contaminated soils is essential for safe agricultural or urban land use, and phytoremediation is among the most effective methods. The success of phytoremediation relies on the size of the plant biomass and bioavailability of the metal for plant uptake. This research was carried out to determine the effect of Ethylenediaminetetraacetic acid (EDTA) ligand and Cu-resistant plant growth-promoting rhizobacteria (PGPR) on phytoremediation efficiency of selected plants as well as fractionation and bioavailability of copper (Cu) in a contaminated soil. The test conditions included three plant species (maize: Zea mays L., sunflower: Helianthus annuus L., and pumpkin: Cucurbita pepo L.) and six treatments, comprising two PGPR strains (Pseudomonas cedrina K4 and Stenotrophomonas sp. A22), two PGPR strains with EDTA, EDTA, and control (without PGPR and EDTA). The combination of EDTA and PGPR enhanced the Cu concentration in both shoot and root tissues and increased the plant biomass. The Cu specific uptake was at a maximum level in the shoots of pumpkin plants when treated with the PGPR strain K4 + EDTA (202 µg pot-1), and the minimum amount of Cu was recorded for sunflower with no PGPR or EDTA addition (29.6 µg pot-1). The result of the PGPR-EDTA treatments showed that the combined application of EDTA and PGPR increased the shoot Cu-specific uptake approximately fourfold in pumpkin. Pumpkin with the highest shoot Cu specific uptake and maize with the highest root Cu specific uptake were the most effective plants in phytoextraction and phytostabilization, respectively. The effectiveness of different PGPR-EDTA treatments in increasing Cu specific uptake by crop plants was assessed by measuring the amount of Cu extracted from the rhizosphere soil adhering to the roots of crop species, by the use of the single extractants Diethylenetriamine pentaacetic acid (DTPA), H2O, NH4NO3, and NH4OAc. PGPR-EDTA treatments increased the amount of water-extractable Cu from rhizosphere soils more than ten times that of the control. The combined application of the EDTA and PGPR reduced the carbonated Fe and Mn oxide-bound Cu in the contaminated soil, and increased the soluble and exchangeable concentration of Cu. Pumpkin, with high shoot biomass and the highest shoot Cu specific uptake was found to be the most effective field crop in phytoextraction of Cu from the contaminated soil. The results of this pot study demonstrated that the EDTA+PGPR treatment could play an important role in increasing the Cu bioavailability and specific uptake by plants, and thus increasing the phytoremediation efficiency of plants in Cu-contaminated areas.


Assuntos
Biodegradação Ambiental/efeitos dos fármacos , Cobre/toxicidade , Ácido Edético/farmacologia , Pseudomonas/efeitos dos fármacos , Poluentes do Solo/toxicidade , Inoculantes Agrícolas , Disponibilidade Biológica , Biomassa , Cobre/análise , Cobre/farmacocinética , Cucurbita/efeitos dos fármacos , Cucurbita/microbiologia , Helianthus/efeitos dos fármacos , Helianthus/microbiologia , Brotos de Planta/efeitos dos fármacos , Pseudomonas/fisiologia , Rizosfera , Poluentes do Solo/farmacocinética , Zea mays/efeitos dos fármacos , Zea mays/microbiologia
9.
J Mater Sci Mater Med ; 30(9): 108, 2019 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-31535222

RESUMO

Biological effects of titanium (Ti) alloys were analyzed on biofilms of Candida albicans, Enterococcus faecalis, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus mutans, and Streptococcus sanguinis, as well as on osteoblast-like cells (MG63) and murine macrophages (RAW 264.7). Standard samples composed of aluminum and vanadium (Ti-6Al-4V), and sample containing niobium (Ti-35Nb) and zirconium (Ti-13Nb-13Zr) were analyzed. Monomicrobial biofilms were formed on the Ti alloys. MG63 cells were grown with the alloys and the biocompatibility (MTT), total protein (TP) level, alkaline phosphatase (ALP) activity, and mineralization nodules (MN) formation were verified. Levels of interleukins (IL-1ß and IL-17), tumor necrosis factor alpha (TNF-α), and oxide nitric (NO) were checked, from RAW 264.7 cells supernatants. Data were statically analyzed by one-way analysis of variance (ANOVA) and Tukey's test, or T-test (P ≤ 0.05). Concerning the biofilm formation, Ti-13Nb-13Zr alloy showed the best inhibitory effect on E. faecalis, P. aeruginosa, and S. aureus. And, it also acted similarly to the Ti-6Al-4V alloy on C. albicans and Streptococcus spp. Both alloys were biocompatible and similar to the Ti-6Al-4V alloy. Additionally, Ti-13Nb-13Zr alloy was more effective for cell differentiation, as observed in the assays of ALP and MN. Regarding the stimulation for release of IL-1ß and TNF-α, Ti-35Nb and Ti-13Nb-13Zr alloys inhibited similarly the synthesis of these molecules. However, both alloys stimulated the production of IL-17. Additionally, all Ti alloys showed the same effect for NO generation. Thus, Ti-13Nb-13Zr alloy was the most effective for inhibition of biofilm formation, cell differentiation, and stimulation for release of immune mediators.


Assuntos
Ligas/farmacologia , Materiais Biocompatíveis/farmacologia , Biofilmes/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Titânio/farmacologia , Ligas/química , Animais , Materiais Biocompatíveis/química , Biofilmes/crescimento & desenvolvimento , Candida albicans/efeitos dos fármacos , Candida albicans/fisiologia , Células Cultivadas , Teste de Materiais , Camundongos , Testes de Sensibilidade Microbiana , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Osteoblastos/fisiologia , Pseudomonas/efeitos dos fármacos , Pseudomonas/fisiologia , Células RAW 264.7 , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/fisiologia , Streptococcus/efeitos dos fármacos , Streptococcus/fisiologia , Propriedades de Superfície , Titânio/química
10.
Microbiol Res ; 228: 126305, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31422234

RESUMO

Traditional culture-based enumeration methods were compared with the ethidium monoazide quantitative polymerase chain reaction (EMA-qPCR) technique to assess Bdellovibrio-and-like-organisms (BALOs) predator-prey interactions. Gram-negative [Pseudomonas spp. and Klebsiella pneumoniae (K. pneumoniae)] and Gram-positive [Staphylococcus aureus (S. aureus) and Enterococcus faecium (E. faecium)] organisms were employed as prey cells, while a Bdellovibrio bacteriovorus strain (PF13) was used as the predator. The co-culture experiments were also compared in diluted nutrient broth (DNB) and HEPES buffer. In both media, K. pneumoniae (maximum log reduction of 5.13) and Pseudomonas fluorescens (P. fluorescens) (maximum log reduction of 4.21) were sensitive to predation by B. bacteriovorus PF13 as their cell counts and gene copies were reduced during all the co-culture experiments, while the concentration of B. bacteriovorus PF13 increased. The concentration of B. bacteriovorus PF13 also increased in the presence of S. aureus (HEPES buffer) and E. faecium (DNB), indicating that the predator interacted with these Gram-positive prey in order to survive. Moreover, as no predator plaques were produced in the co-culture experiments with P. aeruginosa (DNB and HEPES buffer), S. aureus (DNB and HEPES buffer) and E. faecium (HEPES buffer), EMA-qPCR proved to be beneficial in monitoring the concentration of B. bacteriovorus. In conclusion, the cell counts and/or EMA-qPCR analysis for the HEPES buffer and DNB assays were successfully employed to monitor the predation of P. fluorescens and K. pneumoniae by B. bacteriovorus, while E. faecium was sensitive to predation in DNB and S. aureus was sensitive to predation in HEPES buffer.


Assuntos
Azidas , Fenômenos Fisiológicos Bacterianos , Interações Microbianas/fisiologia , Reação em Cadeia da Polimerase em Tempo Real/métodos , Bactérias , Bdellovibrio bacteriovorus/fisiologia , Técnicas de Cocultura , Contagem de Colônia Microbiana , Enterococcus faecium/fisiologia , Klebsiella pneumoniae/fisiologia , Pseudomonas/fisiologia , Staphylococcus aureus/fisiologia , Águas Residuárias/microbiologia , Purificação da Água
11.
Fish Shellfish Immunol ; 93: 949-957, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31433996

RESUMO

Pseudomonas plecoglossicida is a Gram-negative aerobic bacterium that causes high mortality and serious economic losses in some commercial marine fish. Expression of secY was found to be significantly upregulated at 18 °C compared to 28 °C by RNA-seq and qRT-PCR. All five tested recombinant vectors (pCM130/tac + shRNA) significantly reduced secY mRNA levels in P. plecoglossicida. The recombinant vector encoding shRNA-1165 exhibited the best gene-silencing efficiency, 82.4% and was used to create an RNAi strain for further studies. Compared with the wildtype strain, infections of Larimichthys crocea with the RNAi strain resulted in a 2-day delay in onset time and a 35% reduction in mortality, as well as the alleviation of spleen symptoms. The spleens of L. crocea infected by the wild type or RNAi strain of P. plecoglossicida were subjected to dual RNA-seq at 2 dpi. Compared with the wildtype strain, infection of P. plecoglossicida with the RNAi strain resulted in significant changes in the transcriptomes of both host and pathogen. KEGG analysis showed that the complement and coagulation cascade and the Toll-like receptor signalling pathway were the most enriched host pathways. In the pathogen, genes of the "Sec secretion system" were significantly downregulated. This downregulation of "Sec secretion system" genes hindered the secretion of bacterial proteins and reduced the virulence of P. plecoglossicida. Thus, it was easier for L. crocea to clear the RNAi strain of P. plecoglossicida, and the immune response was similarly reduced. The results indicated that secY was a virulence gene of P. plecoglossicida and played roles in the host-pathogen interactions of L. crocea and P. plecoglossicida.


Assuntos
Proteínas de Bactérias/genética , Doenças dos Peixes/imunologia , Interações Hospedeiro-Patógeno/imunologia , Imunidade Inata/genética , Perciformes/imunologia , Canais de Translocação SEC/genética , Animais , Proteínas de Bactérias/metabolismo , Pseudomonas/fisiologia , Infecções por Pseudomonas/imunologia , Infecções por Pseudomonas/veterinária , Canais de Translocação SEC/metabolismo
12.
Arch Microbiol ; 201(10): 1333-1349, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31309236

RESUMO

The present study aims to characterize nodule endophytic bacteria of spontaneous lupine plants regarding their diversity and their plant growth promoting (PGP) traits. The potential of PGPR inoculation was investigated to improve white lupine growth across controlled, semi-natural and field conditions. Lupinus luteus and Lupinus angustifolius nodules were shown inhabited by a large diversity of endophytes. Several endophytes harbor numerous plant growth promotion traits such as phosphates solubilization, siderophores production and 1-aminocyclopropane-1-carboxylate deaminase activity. In vivo analysis confirmed the plant growth promotion ability of two strains (Paenibacillus glycanilyticus LJ121 and Pseudomonas brenneri LJ215) in both sterilized and semi-natural conditions. Under field conditions, the co-inoculation of lupine by these strains increased shoot N content and grain yield by 25% and 36%, respectively. These two strains Paenibacillus glycanilyticus LJ121 and Pseudomonas brenneri LJ215 are effective plant growth-promoting bacteria and they may be used to develop an eco-friendly biofertilizer to boost white lupine productivity.


Assuntos
Endófitos/fisiologia , Lupinus/microbiologia , Paenibacillus/fisiologia , Raízes de Plantas/microbiologia , Pseudomonas/fisiologia , Microbiologia do Solo , Endófitos/genética , Endófitos/isolamento & purificação , Lupinus/crescimento & desenvolvimento , Desenvolvimento Vegetal , Caules de Planta/química , Caules de Planta/microbiologia , Sideróforos/metabolismo , Tunísia
13.
Plant Physiol Biochem ; 142: 179-192, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31299600

RESUMO

Soil micro-biota plays a vital role in maintaining plant growth and fitness under normal and adverse conditions. Pseudomonas is one of the most important free-living and copious genera in south-west Punjab and involved in plant growth promotion under heavy metal stress. In this study, we have studied microbial diversity of the agricultural and marginal land based on 16S rRNA gene and screened eight strains of Pseudomonas for its tolerances towards various heavy metals and for plant growth promoting properties (PGP). The best strain is tested in chickpea plants against Arsenic (As5+) stress. All the strains responded differently to heavy metals viz. Arsenic, (As5+ (0.3-0.5M) and As3+ (250 µg mL-1) Cadmium (Cd2+) (250-350 µg mL-1), Chromium (Cr2+) (200-350 µg mL-1) and Mercury (Hg2+) (1-2 µg mL-1). Out of eight strains, only two strains (KM594398 and KM594397) showed plant growth promoting characters, concurrently they were highly tolerant to Arsenic (As5+). Pseudomonas citronellolis (PC) (KM594397) showed the best results in terms of As5+ tolerance and plant growth promoting activity, hence further tested for actual plant growth response in chickpea (Cicer arietinum L.) under As5+ (10-160 mg kg-1) stress. Pseudomonas citronellolis enhanced plant growth and dry biomass under As5+ stress. High As5+ tolerance and plant growth promoting activity of Pseudomonas citronellolis in chickpea especially designate this strain suitable for marginal lands and heavy metals contaminated sites.


Assuntos
Arsênico/toxicidade , Cicer/efeitos dos fármacos , Cicer/microbiologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Pseudomonas/efeitos dos fármacos , Pseudomonas/fisiologia , Inoculantes Agrícolas , Clorofila/metabolismo , Cicer/crescimento & desenvolvimento , Eletrólitos/metabolismo , Poluição Ambiental , Índia , Malondialdeído/metabolismo , Metais Pesados/toxicidade , Filogenia , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/crescimento & desenvolvimento , Pseudomonas/isolamento & purificação , RNA Ribossômico 16S , Microbiologia do Solo
14.
Microb Cell Fact ; 18(1): 121, 2019 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-31277643

RESUMO

BACKGROUND: Fungal perylenequinonoid (PQ) pigments from Shiraia fruiting body have been well known as excellent photosensitizers for medical and agricultural uses. The fruiting bodies are colonized by a diverse bacterial community of unknown function. We screened the companion bacteria from the fruiting body of Shiraia sp. S9 and explored the bacterial elicitation on fungal PQ production. RESULTS: A bacterium Pseudomonas fulva SB1 isolated from the fruiting body was found to stimulate the production of fungal PQs including hypocrellins A, C (HA and HC), and elsinochromes A-C (EA, EB and EC). After 2 days of co-cultures, Shiraia mycelium cultures presented the highest production of HA (325.87 mg/L), about 3.20-fold of that in axenic culture. The co-culture resulted in the induction of fungal conidiation and the formation of more compact fungal pellets. Furthermore, the bacterial treatment up-regulated the expression of polyketide synthase gene (PKS), and activated transporter genes of ATP-binding cassette (ABC) and major facilitator superfamily transporter (MFS) for PQ exudation. CONCLUSIONS: We have established a bacterial co-culture with a host Shiraia fungus to induce PQ biosynthesis. Our results provide a basis for understanding bacterial-fungal interaction in fruiting bodies and a practical co-culture process to enhance PQ production for photodynamic therapy medicine.


Assuntos
Ascomicetos/metabolismo , Carpóforos/metabolismo , Perileno/análogos & derivados , Pseudomonas/fisiologia , Quinonas/metabolismo , Ascomicetos/genética , Técnicas de Cocultura , Proteínas Fúngicas/genética , Interações Microbianas , Perileno/metabolismo , Policetídeo Sintases/genética , Pseudomonas/isolamento & purificação , Esporos Fúngicos
15.
Fish Shellfish Immunol ; 93: 344-353, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31352116

RESUMO

Large yellow croaker (Larimichthys crocea) is an economical important farmed fish in China. "Visceral White Spot Disease" caused by Pseudomonas plecoglossicida is a disease with a high mortality rate in cage-cultured L. crocea in recent years and resulted in heavy economy lossess. The dual RNA-seq results of previous study showed that the expression of clpV gene in P. plecoglossicida was significantly up-regulated during infection. RNAi significantly reduced the expression of clpV in P. plecoglossicida with maximum silencing efficiency of 96.1%. Compared with the wild type strain, infection of clpV-RNAi strain resulted in a delayed onset time and a 25% reduction in mortality of L. crocea, as well as lessening the symptoms of the spleen. The results of dual RNA-seq of L. crocea infected by clpV-RNAi strain of P. plecoglossicida changed considerably, compared with the counterpart infected with the wild strain. The KEGG enrichment analysis showed that Cytokine-cytokine receptor interaction, Toll-like receptor signaling pathway, C-type lectin receptor signaling pathway and MAPK signaling pathway of L. crocea were most affected by the silence of clpV in P. plecoglossicida. RNAi of clpV resulted in the downregulation of genes in flagella assembly pathway and a weaker immune response of host.


Assuntos
Proteínas de Bactérias/genética , Doenças dos Peixes/imunologia , Interações Hospedeiro-Patógeno/imunologia , Perciformes/imunologia , Transcriptoma/imunologia , Animais , Proteínas de Bactérias/metabolismo , Pseudomonas/fisiologia , Infecções por Pseudomonas/imunologia , Infecções por Pseudomonas/veterinária , Interferência de RNA , Baço/metabolismo , Baço/microbiologia
16.
Curr Microbiol ; 76(10): 1168-1174, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31263923

RESUMO

A Gram-negative, strictly aerobic, motile, rod-shaped bacterium with monopolar flagellum, designated as F51T, was isolated from the skin ulcer of farmed Murray cod sampled from Zhejiang Province, China. Strain F51T grew at 4-37 °C (optimal temperature, 28 °C), pH 5.0-8.5 (optimal pH, 7.5) and NaCl concentration of 0-6.0% (w/v) (optimal concentration, 2.0%). Phylogenetic analysis based on average nucleotide identity (76.2-78.4%) and in silico DNA-DNA hybridization (22.3-23.2%) values revealed that strain F51T forms a distinct lineage in the clade of genus Pseudomonas with less than 98.9% 16S rRNA gene sequence similarity to type strains of the genus and represents a novel species related most closely to Pseudomonas floridensis LMG 30013T. Three housekeeping genes (rpoB, rpoD and gyrB) of strain F51T were analysed to further confirm that the isolate is distinctly delineated from related Pseudomonas species. Chemotaxonomic analysis indicated that the sole respiratory quinone of strain F51T is Q-9; its predominant cellular fatty acids are C16:0, summed feature 3 (iso-C15:0 2-OH and/or C16:1ω7c), summed feature 8 (C18:1ω7c and/or C18:1ω6c) and C10:0 3-OH; and its major polar lipids consist of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, two unidentified glycolipids, three unidentified phospholipids and an unidentified aminophosphoglycolipid. This composition is typical of the chemotaxonomic attributes of Pseudomonas. Based on its phenotypic, chemotaxonomic and phylogenetic features, strain F51T is considered to represent a novel species for which the name Pseudomonas ovata sp. nov. is proposed. The type strain is F51T (= KCTC 62133T = MCCC 1K03458T).


Assuntos
Doenças dos Peixes/microbiologia , Perciformes/microbiologia , Filogenia , Pseudomonas/classificação , Pseudomonas/fisiologia , Animais , Aquicultura , Composição de Bases , China , DNA Bacteriano/genética , Genes Bacterianos/genética , Genoma Bacteriano/genética , Lipídeos/química , Hibridização de Ácido Nucleico , Pseudomonas/química , Pseudomonas/genética , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Especificidade da Espécie
17.
Artigo em Inglês | MEDLINE | ID: mdl-31195653

RESUMO

One effective method in to reduce the uptake of organic contaminants by plants is the development of a root barrier. In this study, the characterization of biofilm structure and function by phenanthrene-degrading Pseudomonas sp. JM2-gfp on rice root surfaces were carried out. Our results showed that root surfaces from three rice species, namely Liaojing401, Koshihikari, and Zhenzhuhong all present hydrophobicity and a high initial adhesion of strain JM2-gfp. Matured robust biofilm formation occurred at 48 h on the root surfaces. The biofilm exhibited cell dense aggregates and biomass embedded in the extracellular polymeric substance (EPS) matrix. EPS composition results showed that the proteins, carbohydrates, lipids and nucleic acids are produced in the biofilm, while the content varied with rice species. Under the initial concentration of phenanthrene 50 mg·L-1, the residual phenanthrene in plant roots from 'Zhengzhuhong', 'Koshihikari' and 'Liaojing401' with biofilm mediated were significantly decreased by 71.9%, 69.3% and 58.7%, respectively, compared to those without biofilm groups after 10 days of exposure. Thus, the biofilm colonized on roots plays an important role of degradation in order to reduce the level of phenanthrene uptake of plants. Thereby, the present work provides significant new insights into lowering the environmental risks of polycyclic aromatic hydrocarbons (PAHs) in crop products from contaminated agriculture soils.


Assuntos
Biofilmes/crescimento & desenvolvimento , Oryza/microbiologia , Fenantrenos/metabolismo , Raízes de Plantas/microbiologia , Pseudomonas/fisiologia , Poluentes do Solo/metabolismo , Biodegradação Ambiental , Matriz Extracelular de Substâncias Poliméricas/metabolismo , Oryza/metabolismo , Raízes de Plantas/metabolismo
18.
Extremophiles ; 23(5): 587-597, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31250111

RESUMO

Reactive oxygen species and nitrogen species (ROS and RNS), produced in a wide range of physiological process even under low oxygen availability, are among the main stressors found in the environment. Strategies developed to combat them constitute key features in bacterial adaptability and survival. Pseudomonas extremaustralis is a metabolic versatile and stress resistant Antarctic bacterium, able to grow under different oxygen conditions. The present work explores the effect of oxidative stress under low oxygen conditions in P. extremaustralis, by combining RNA deep sequencing analysis and physiological studies. Cells grown under microaerobiosis exhibited more oxidative damage in macromolecules and lower survival rates than under aerobiosis. RNA-seq analysis showed an up-regulation of genes related with oxidative stress response, flagella, chemotaxis and biofilm formation while chaperones and cytochromes were down-regulated. Microaerobic cultures exposed to H2O2 also displayed a hyper-flagellated phenotype coupled with a high motility behavior. Moreover, cells that were subjected to oxidative stress presented increased biofilm formation. Altogether, our results suggest that a higher motile behavior and augmented capacity to form biofilm structures could work in addition to well-known antioxidant enzymes and non-enzymatic ROS scavenging mechanisms to cope with oxidative stress at low oxygen tensions.


Assuntos
Quimiotaxia , Flagelos/metabolismo , Estresse Oxidativo , Pseudomonas/metabolismo , Transcriptoma , Biofilmes , Genes Bacterianos , Oxigênio/metabolismo , Pseudomonas/genética , Pseudomonas/fisiologia
19.
Nat Commun ; 10(1): 2120, 2019 05 09.
Artigo em Inglês | MEDLINE | ID: mdl-31073166

RESUMO

All organisms are sensitive to the abiotic environment, and a deteriorating environment can cause extinction. However, survival in a multispecies community depends upon interactions, and some species may even be favored by a harsh environment that impairs others, leading to potentially surprising community transitions as environments deteriorate. Here we combine theory and laboratory microcosms to predict how simple microbial communities will change under added mortality, controlled by varying dilution. We find that in a two-species coculture, increasing mortality favors the faster grower, confirming a theoretical prediction. Furthermore, if the slower grower dominates under low mortality, the outcome can reverse as mortality increases. We find that this tradeoff between growth and competitive ability is prevalent at low dilution, causing outcomes to shift dramatically as dilution increases, and that these two-species shifts propagate to simple multispecies communities. Our results argue that a bottom-up approach can provide insight into how communities change under stress.


Assuntos
Comunicação Celular/fisiologia , Microbiota/fisiologia , Modelos Biológicos , Microbiologia do Solo , Enterobacter aerogenes/fisiologia , Pseudomonas/fisiologia
20.
Fish Shellfish Immunol ; 92: 45-53, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31129188

RESUMO

As an important pathogen in aquaculture, Pseudomonas plecoglossicida has caused heavy losses. The expression of an ABC transporter gene-L321_23611 of P. plecoglossicida at 18 °C was found significant higher than those at 28 °C by RNA-seq and qRT-PCR. RNAi significantly reduced the content of L321_23611 mRNA in P. plecoglossicida with a maximal decrease of 89.2%. Compared with the wild type strain, the infection of L321_23611-RNAi strain resulted in the reduction in mortality and the onset time delay of a kind of marine teleosts, Epinephelus coioides. The results of dual RNA-seq showed that the RNAi of L321_23611 resulted in a significant change in both pathogen and host transcriptome in the spleens of infected E. coioides. The result of GO and KEGG analysis from dual RNA-seq data showed both host genes of chemokine signaling pathway, coagulation and complement system, hematopoietic cell lineage pathway as well as hemoglobin complex GO term and pathogenic genes of bacterial-type flagellum-dependent cell mortality GO term and flagellar assembly, biosynthesis of amino acids and lysine biosynthesis systems pathways were mainly affected by L321_23611 gene of P. plecoglossicida. The results indicated that: 1. ABC transporter gene-L321_23611 was a virulent gene of P. plecoglossicida. 2. Both the activation of the host immune pathways and depression of pathogenic virulence-related pathways facilitated E. coioides to remove L321_23611-RNAi strain than the wild type strain of P. plecoglossicida.


Assuntos
Transportadores de Cassetes de Ligação de ATP/imunologia , Bass , Doenças dos Peixes/imunologia , Proteínas de Peixes/imunologia , Interações Hospedeiro-Patógeno/genética , Imunidade Inata/genética , Transportadores de Cassetes de Ligação de ATP/genética , Animais , Doenças dos Peixes/genética , Proteínas de Peixes/genética , Pseudomonas/fisiologia , Infecções por Pseudomonas/genética , Infecções por Pseudomonas/imunologia , Infecções por Pseudomonas/veterinária , Análise de Sequência de RNA/veterinária
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