Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 49
Filtrar
1.
Plant Pathol J ; 36(4): 378-383, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32788896

RESUMO

The objective of this research was introduction of chit42 to tuber mustard plants through Agrobacteriummediated transformation against white mold caused by Sclerotinia sclerotiorum. The binary plasmid pGisPEC1 was used in this study. Polymerase chain reaction analysis detected the transgene in 27 transformants with a transformation efficiency of 6.9%. Southern blot test was used to assess the copy number of transgene in tuber mustard plants. One, two, two, and two chit42-related bands were observed in the transformed lines TMB4, TMB7, TMB12, and TMB18, respectively. Enzymatic tests showed a significant increase in the activity of endochitinase in protein isolated from leaf tissues of chit42 transgenic 75-day tuber mustard lines. The pathogenicity of three pathogen isolates was tested on the leaves of transformed plans. The results of current study showed that expression of the gene chit42 in tuber mustard plants markedly reduced infection radius on the leaves 7 days after inoculation with the fungus.

2.
Molecules ; 21(8)2016 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-27472315

RESUMO

Camptothecin (CPT) has anticancer, antiviral, and antifungal properties. However, there is a dearth of information about antibacterial activity of CPT. Therefore, in this study, we investigated the inhibitory effect of CPT on Acidovorax avenae subsp. avenae strain RS-2, the pathogen of rice bacterial brown stripe, by measuring cell growth, DNA damage, cell membrane integrity, the expression of secretion systems, and topoisomerase-related genes, as well as the secretion of effector protein Hcp. Results indicated that CPT solutions at 0.05, 0.25, and 0.50 mg/mL inhibited the growth of strain RS-2 in vitro, while the inhibitory efficiency increased with an increase in CPT concentration, pH, and incubation time. Furthermore, CPT treatment affected bacterial growth and replication by causing membrane damage, which was evidenced by transmission electron microscopic observation and live/dead cell staining. In addition, quantitative real-time PCR analysis indicated that CPT treatment caused differential expression of eight secretion system-related genes and one topoisomerase-related gene, while the up-regulated expression of hcp could be justified by the increased secretion of Hcp based on the ELISA test. Overall, this study indicated that CPT has the potential to control the bacterial brown stripe pathogen of rice.


Assuntos
Antibacterianos/farmacologia , Camptotecina/farmacologia , Comamonadaceae/crescimento & desenvolvimento , Oryza/microbiologia , Doenças das Plantas/prevenção & controle , Proteínas de Bactérias/genética , Membrana Celular/efeitos dos fármacos , Comamonadaceae/efeitos dos fármacos , Relação Dose-Resposta a Droga , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Testes de Sensibilidade Microbiana , Doenças das Plantas/microbiologia
3.
ISME J ; 10(8): 2072-5, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-26859773

RESUMO

Different lifestyles, ranging from a saprophyte to a pathogen, have been reported in bacteria of one species. Here, we performed genome-wide survey of the ecological adaptation in four Burkholderia seminalis strains, distinguished by their origin as part of the saprophytic microbial community of soil or water but also including human and plant pathogens. The results indicated that each strain is separated from the others by increased fitness in medium simulating its original niche corresponding to the difference between strains in metabolic capacities. Furthermore, strain-specific metabolism and niche survival was generally linked with genomic variants and niche-dependent differential expression of the corresponding genes. In particular, the importance of iron, trehalose and d-arabitol utilization was highlighted by the involvement of DNA-methylation and horizontal gene transfer in niche-adapted regulation of the corresponding operons based on the integrated analysis of our multi-omics data. Overall, our results provided insights of niche-specific adaptation in bacteria.


Assuntos
Adaptação Fisiológica , Burkholderia/fisiologia , Genoma Bacteriano/genética , Genômica , Burkholderia/genética , Ecologia , Transferência Genética Horizontal , Humanos , Plantas/microbiologia , Solo , Microbiologia do Solo , Especificidade da Espécie
4.
Pestic Biochem Physiol ; 127: 8-14, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26821652

RESUMO

This study was conducted to determine the inhibitory effect of E-cinnamaldehyde (EC) against causal agent of storage carrot rot, Sclerotinia sclerotiorum, under in vivo and in vitro conditions. Based on the results, EC was able to completely inhibit mycelial growth of three isolates (P>0.05) in both volatile and contact phases after 6days at the concentrations 200µl and 1µl/ml, respectively. In addition, EC at concentrations 1 and 10µl/ml completely inhibited carpogenic germination of three isolates. The results of in vivo trials showed that EC at the concentration of 10µl/ml was able to control the disease caused by isolates 1 and 3. However the disease caused by isolate 2 was inhibited with the concentration of 20µl/ml. In enzyme analyses, the activity of polyphenoloxidase and peroxidase did not change in the inoculated carrots after application of EC. Furthermore, the level of phenylalanine ammonia lyase decreased. These results indicated that EC does not have any potential to be considered as resistance inducers against sclerotinia carrot rot.


Assuntos
Acroleína/análogos & derivados , Ascomicetos/efeitos dos fármacos , Daucus carota/microbiologia , Acroleína/farmacologia , Daucus carota/crescimento & desenvolvimento , Germinação , Testes de Sensibilidade Microbiana , Doenças das Plantas
5.
Int J Mol Sci ; 16(9): 22008-26, 2015 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-26378528

RESUMO

Valine glycine repeat G (VgrG) proteins are regarded as one of two effectors of Type VI secretion system (T6SS) which is a complex multi-component secretion system. In this study, potential biological roles of T6SS structural and VgrG genes in a rice bacterial pathogen, Acidovorax avenae subsp. avenae (Aaa) RS-1, were evaluated under seven stress conditions using principle component analysis of gene expression. The results showed that growth of the pathogen was reduced by H2O2 and paraquat-induced oxidative stress, high salt, low temperature, and vgrG mutation, compared to the control. However, pathogen growth was unaffected by co-culture with a rice rhizobacterium Burkholderia seminalis R456. In addition, expression of 14 T6SS structural and eight vgrG genes was significantly changed under seven conditions. Among different stress conditions, high salt, and low temperature showed a higher effect on the expression of T6SS gene compared with host infection and other environmental conditions. As a first report, this study revealed an association of T6SS gene expression of the pathogen with the host infection, gene mutation, and some common environmental stresses. The results of this research can increase understanding of the biological function of T6SS in this economically-important pathogen of rice.


Assuntos
Comamonadaceae/genética , Interação Gene-Ambiente , Viabilidade Microbiana/genética , Análise de Componente Principal , Sistemas de Secreção Tipo VI/genética , Meio Ambiente , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos , Estresse Fisiológico
6.
Sci Rep ; 5: 10841, 2015 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-26042679

RESUMO

The fabrication and control of the conductive surface and interface on insulating SrTiO3 bulk provide a pathway for oxide electronics. The controllable manipulation of local doping concentration in semiconductors is an important step for nano-electronics. Here we show that conductive patterns can be written on bare SrTiO3 surface by controllable doping in nanoscale using the mechanical interactions of atomic force microscopy tip without applying external electric field. The conductivity of the layer is n-type, oxygen sensitive, and can be effectively tuned by the gate voltage. Hence, our findings have potential applications in oxide nano-circuits and oxygen sensors.

7.
Microb Ecol ; 69(1): 75-83, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25081413

RESUMO

Outer membrane proteins (OMPs) are integral ß-barrel proteins of the Gram-negative bacterial cell wall and are crucial to bacterial survival within the macrophages and for eukaryotic cell invasion. Here, we used liquid chromatography tandem mass spectrometry (LC-MS/MS) to comprehensively assess the outer membrane proteome of Burkholderia cenocepacia, an opportunistic pathogen causing cystic fibrosis (CF), in conditions mimicking four major ecological niches: water, CF sputum, soil, and plant leaf. Bacterial cells were harvested at late log phase, and OMPs were extracted following the separation of soluble proteins by one-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (1D-SDS-PAGE). Protein bands were excised and identified by LC-MS/MS analysis. The proteins identified under various growth conditions were further subjected to in silico analysis of gene ontology (subcellular localization, structural, and functional analyses). Overall, 72 proteins were identified as common to the four culture conditions, while 33, 37, 20, and 10 proteins were exclusively identified in the water, CF sputum, soil, and plant leaf environments, respectively. The functional profiles of the majority of these proteins revealed significant diversity in protein expression between the four environments studied and may indicate that the protein expression profiles are unique for every condition. Comparison of OMPs from one strain in four distinct ecological niches allowed the elucidation of proteins that are essential for survival in each niche, while the commonly expressed OMPs, such as RND efflux system protein, TonB-dependent siderophore receptor, and ABC transporter-like protein, represent promising targets for drug or vaccine development.


Assuntos
Proteínas da Membrana Bacteriana Externa/metabolismo , Burkholderia cenocepacia/metabolismo , Proteoma/análise , Proteínas da Membrana Bacteriana Externa/genética , Burkholderia cenocepacia/genética , Eletroforese em Gel de Poliacrilamida , Sequências de Repetição em Tandem/genética
8.
Front Microbiol ; 5: 547, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25374564

RESUMO

Acidovorax avenae subsp. avenae is the causal agent of bacterial brown stripe disease in rice. In this study, we characterized a novel horizontal transfer of a gene cluster, including tetR, on the chromosome of A. avenae subsp. avenae RS-1 by genome-wide analysis. TetR acted as a repressor in this gene cluster and the oxidative stress resistance was enhanced in tetR-deletion mutant strain. Electrophoretic mobility shift assay demonstrated that TetR regulator bound directly to the promoter of this gene cluster. Consistently, the results of quantitative real-time PCR also showed alterations in expression of associated genes. Moreover, the proteins affected by TetR under oxidative stress were revealed by comparing proteomic profiles of wild-type and mutant strains via 1D SDS-PAGE and LC-MS/MS analyses. Taken together, our results demonstrated that tetR gene in this novel gene cluster contributed to cell survival under oxidative stress, and TetR protein played an important regulatory role in growth kinetics, biofilm-forming capability, superoxide dismutase and catalase activity, and oxide detoxicating ability.

9.
Artigo em Inglês | MEDLINE | ID: mdl-24996215

RESUMO

Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas oryzae pv. oryzicola (Xoc) strains are closely related phenotypically and genetically, which make it difficult to differentiate between the two pathovars based on phenotypic and DNA-based methods. In this study, a fast and accurate method was developed based on the differences in MALDI-TOF MS and FTIR spectra between the two pathovars. MALDI-TOF MS analysis revealed that 9 and 10 peaks are specific to Xoo and Xoc, respectively, which can be used as biomarkers to identify and differentiate the two closely related pathovars. Furthermore, FTIR analysis showed that there is a significant difference in both the band frequencies and absorption intensity of various functional groups between the two pathovars. In particular, the 6 peaks at 3433, 2867, 1273, 1065, 983 and 951cm(-1) were specific to the Xoo strains, while one peak at 1572cm(-1) was specific to the Xoc strains. Overall, this study gives the first attempt to identify and differentiate the two pathovars of X. oryzae based on mass and FTIR spectra, which will be helpful for the early detection and prevention of the two rice diseases caused by both X. oryzae pathovars.


Assuntos
Técnicas de Tipagem Bacteriana/métodos , Oryza/microbiologia , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Xanthomonas/química , Xanthomonas/classificação
10.
Molecules ; 19(7): 9975-85, 2014 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-25010469

RESUMO

Burkholderia glumae has been proposed to have a potential risk to vulnerable communities. In this work, we investigated the antibacterial activity and mechanism of copper surfaces against multi-drug resistant B. glumae from both patients and rice plants. The susceptibility of B. glumae to copper surfaces was noted by a significant decline in viable bacterial counts, relative to the slight reduction of stainless steel and polyvinylchloride, both of which were used as control surfaces. The mode of action of bacterial killing was determined by examing the mutagenicity, DNA damage, copper ions accumulation, and membrane damage in bacterial cells. The results indicated that the cells exposed to copper surfaces did not cause severe DNA lesions or increase the mutation frequencies, but resulted in a loss of cell membrane integrity within minutes. Furthermore, bacterial cells exposed to copper surfaces accumulated significantly higher amounts of copper compared to control surfaces. Overall, this study showed that metallic copper had strong antibacterial effect against B. glumae by causing DNA and membrane damage, cellular accumulation of copper, and cell death following DNA degradation, which could be utilized to reduce the risk of bacterial contamination and infection.


Assuntos
Aderência Bacteriana , Burkholderia , Cobre , Antibacterianos , Burkholderia/genética , Membrana Celular , Dano ao DNA , Viabilidade Microbiana , Testes de Mutagenicidade , Propriedades de Superfície
11.
Carbohydr Res ; 391: 48-54, 2014 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-24785387

RESUMO

Inhibitory effect and mode of action of chitosan solution against rice bacterial brown stripe pathogen Acidovorax avenae subsp. avenae (Aaa) strain RS-1 was examined in this study. Result from this study indicated that chitosan solutions at 0.10, 0.20, and 0.40mg/mL inhibited the in vitro growth of Aaa strain RS-1, and in general the inhibitory efficiency increased with the increase of both chitosan concentration and the incubation time. Antibacterial activity of chitosan in this study may be mainly due to the damage of cell membrane, which was evidenced by both the cell lysis observed by transmission electron microscopy, and the increased release of cell materials based on the measurement of cell membrane integrity. Furthermore, chitosan solutions at concentrations of 0.1, 0.2, and 0.4mg/mL markedly inhibited bacterial biofilm formation compared to the control, and the inhibitory effect increased with the increase of chitosan concentration. In addition, quantitative real-time PCR of the 10 secretion system related genes revealed the differential expression of genes in particular ompA/motB, emphasizing the importance of this gene in the response of Aaa strain RS-1 to chitosan stress. These results indicated that the antibacterial mode of action of chitosan may be mainly due to membrane disruption and lysis, reduction of biofilm formation, and gene expression change. Overall, the results clearly indicated that chitosan had the potential to control bacterial brown stripe of rice.


Assuntos
Antibacterianos/farmacologia , Quitosana/farmacologia , Comamonadaceae/efeitos dos fármacos , Oryza/microbiologia , Antibacterianos/química , Quitosana/química , Relação Dose-Resposta a Droga , Testes de Sensibilidade Microbiana , Soluções , Relação Estrutura-Atividade
12.
Arch Microbiol ; 196(1): 9-16, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24213809

RESUMO

Chitosan, a versatile derivative of chitin, is widely used as an antimicrobial agent either alone or mixed with other natural polymers. Burkholderia cenocepacia is a multidrug-resistant bacteria and difficult to eradicate. Our previous studies shown that chitosan had strong antibacterial activity against B. cenocepacia. In the current study, we have investigated the molecular aspects for the susceptibility of B. cenocepacia in response to chitosan antibacterial activity. We have conducted RNA expression analysis of drug efflux system by RT-PCR, membrane protein profiling by SDS-PAGE, and by LC-MS/MS analysis following the validation of selected membrane proteins by real-time PCR analysis. By RT-PCR analysis, it was found that orf3, orf9, and orf13 were expressed at detectable levels, which were similar to control, while rest of the orf did not express. Moreover, shotgun proteomics analysis revealed 21 proteins in chitosan-treated cells and 16 proteins in control. Among them 4 proteins were detected as shared proteins under control and chitosan-treated cells and 17 proteins as uniquely identified proteins under chitosan-treated cells. Among the catalog of uniquely identified proteins, there were proteins involved in electron transport chain and ATP synthase, metabolism of carbohydrates and adaptation to atypical conditions proteins which indicate that utilization and pattern of chitosan is diverse which might be responsible for its antibacterial effects on bacteria. Moreover, our results showed that RND drug efflux system, which display the ability to transport a variety of structurally unrelated drugs from a cell and consequently are capable of conferring resistance to a diverse range of chemotherapeutic agents, was not determined to play its role in response to chitosan. It might be lipopolysaccharides interaction with chitosan resulted in the destabilization of membrane protein to membrane lyses to cell death. Membrane proteome analysis were also validated by RT-qPCR analysis, which corroborated our results that of membrane proteins.


Assuntos
Anti-Infecciosos/farmacologia , Burkholderia cenocepacia/efeitos dos fármacos , Quitosana/farmacologia , Proteínas de Membrana/metabolismo , Farmacorresistência Bacteriana/fisiologia , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos
13.
World J Microbiol Biotechnol ; 30(2): 469-78, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23990042

RESUMO

Biological control efficacy of Brevibacillus laterosporus B4 associated with rice rhizosphere was assessed against bacterial brown stripe of rice caused by Acidovorex avenae subsp. avenae. A biochemical bactericide (chitosan) was used as positive control in this experiment. Result of in vitro analysis indicated that B. laterosporus B4 and its culture filtrates (70%; v/v) exhibited low inhibitory effects than chitosan (5 mg/ml). However, culture suspension of B. laterosporus B4 prepared in 1% saline solution presented significant ability to control bacterial brown stripe in vivo. Bacterization of rice seeds for 24 h yielded a greater response (71.9%) for controlling brown stripe in vivo than chitosan (56%). Studies on mechanisms revealed that B. laterosporus B4 suppressed the biofilm formation and severely disrupted cell membrane integrity of A. avenae subsp. avenae, causing the leakage of intracellular substances. In addition, the expression level of virulence-related genes in pathogen recovered from biocontrol-agent-treated plants showed that the genes responsible for biofilm formation, motility, niche adaptation, membrane functionality and virulence of A. avenae subsp. avenae were down-regulated by B. laterosporus B4 treatment. The biocontrol activity of B. laterosporus B4 was attributed to a substance with protein nature. This protein nature was shown by using ammonium sulfate precipitation and subsequent treatment with protease. The results obtained from this study showed the potential effectiveness of B. laterosporus B4 as biocontrol agent in control of bacterial brown stripe of rice.


Assuntos
Antibiose , Biofilmes/crescimento & desenvolvimento , Brevibacillus/fisiologia , Comamonadaceae/efeitos dos fármacos , Comamonadaceae/fisiologia , Oryza/microbiologia , Doenças das Plantas/microbiologia , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/farmacologia , Brevibacillus/metabolismo , Locomoção/efeitos dos fármacos , Doenças das Plantas/prevenção & controle , Virulência/efeitos dos fármacos , Fatores de Virulência/antagonistas & inibidores
14.
Mar Drugs ; 11(5): 1534-52, 2013 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-23670533

RESUMO

This present study deals with synthesis, characterization and antibacterial activity of cross-linked chitosan-glutaraldehyde. Results from this study indicated that cross-linked chitosan-glutaraldehyde markedly inhibited the growth of antibiotic-resistant Burkholderia cepacia complex regardless of bacterial species and incubation time while bacterial growth was unaffected by solid chitosan. Furthermore, high temperature treated cross-linked chitosan-glutaraldehyde showed strong antibacterial activity against the selected strain 0901 although the inhibitory effects varied with different temperatures. In addition, physical-chemical and structural characterization revealed that the cross-linking of chitosan with glutaraldehyde resulted in a rougher surface morphology, a characteristic Fourier transform infrared (FTIR) band at 1559 cm⁻¹, a specific X-ray diffraction peak centered at 2θ = 15°, a lower contents of carbon, hydrogen and nitrogen, and a higher stability of glucose units compared to chitosan based on scanning electron microscopic observation, FTIR spectra, X-ray diffraction pattern, as well as elemental and thermo gravimetric analysis. Overall, this study indicated that cross-linked chitosan-glutaraldehyde is promising to be developed as a new antibacterial drug.


Assuntos
Antibacterianos/farmacologia , Burkholderia cepacia/efeitos dos fármacos , Quitosana/farmacologia , Glutaral/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , Quitosana/síntese química , Quitosana/química , Reagentes de Ligações Cruzadas/química , Farmacorresistência Bacteriana , Glutaral/síntese química , Glutaral/química , Temperatura Alta , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Termogravimetria , Fatores de Tempo , Difração de Raios X
15.
PLoS One ; 8(5): e62946, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23690965

RESUMO

The rhizosphere isolate Pseudomonas putida BW11M1 produces a mixture of cyclic lipopeptide congeners, designated xantholysins. Properties of the major compound xantholysin A, shared with several other Pseudomonas lipopeptides, include antifungal activity and toxicity to Gram-positive bacteria, a supportive role in biofilm formation, and facilitation of surface colonization through swarming. Atypical is the lipopeptide's capacity to inhibit some Gram-negative bacteria, including several xanthomonads. The lipotetradecadepsipeptides are assembled by XtlA, XtlB and XtlC, three co-linearly operating non-ribosomal peptide synthetases (NRPSs) displaying similarity in modular architecture with the entolysin-producing enzymes of the entomopathogenic Pseudomonas entomophila L48. A shifted serine-incorporating unit in the eight-module enzyme XtlB elongating the central peptide moiety not only generates an amino acid sequence differing at several equivalent positions from entolysin, but also directs xantholysin's macrocyclization into an octacyclic structure, distinct from the pentacyclic closure in entolysin. Relaxed fatty acid specificity during lipoinitiation by XtlA (acylation with 3-hydroxydodec-5-enoate instead of 3-hydroxydecanoate) and for incorporation of the ultimate amino acid by XtlC (valine instead of isoleucine) account for the production of the minor structural variants xantholysin C and B, respectively. Remarkably, the genetic backbones of the xantholysin and entolysin NRPS systems also bear pronounced phylogenetic similarity to those of the P. putida strains PCL1445 and RW10S2, albeit generating the seemingly structurally unrelated cyclic lipopeptides putisolvin (undecapeptide containing a cyclotetrapeptide) and WLIP (nonapeptide containing a cycloheptapeptide), respectively. This similarity includes the linked genes encoding the cognate LuxR-family regulator and tripartite export system components in addition to individual modules of the NRPS enzymes, and probably reflects a common evolutionary origin. Phylogenetic scrutiny of the modules used for selective amino acid activation by these synthetases indicates that bacteria such as pseudomonads recruit and reshuffle individual biosynthetic units and blocks thereof to engineer reorganized or novel NRPS assembly lines for diversified synthesis of lipopeptides.


Assuntos
Anti-Infecciosos/metabolismo , Lipopeptídeos/metabolismo , Peptídeo Sintases/metabolismo , Peptídeos Cíclicos/metabolismo , Filogenia , Pseudomonas putida/metabolismo , Sequência de Bases , Análise por Conglomerados , Ácidos Graxos/metabolismo , Lipopeptídeos/classificação , Lipopeptídeos/genética , Dados de Sequência Molecular , Peptídeo Sintases/genética , Peptídeos Cíclicos/genética , Análise de Sequência de DNA , Especificidade da Espécie , Especificidade por Substrato
16.
J Sci Food Agric ; 93(5): 1010-5, 2013 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-23400827

RESUMO

BACKGROUND: The production of watermelon in China has been seriously hampered by fruit blotch disease and limited control measures are now applied. Chitosan has been employed to control a variety of plant diseases and is considered to be the most promising biochemical to control this disease. RESULTS: The in vitro antibacterial effect of chitosan and its ability in protection of watermelon seedlings from bacterial fruit blotch were evaluated. Results showed that three types of chitosan, in particular, chitosan A at 0.40 mg mL⁻¹ significantly inhibited the growth of Acidovorax citrulli. The antibacterial activity of chitosan A was affected by chitosan concentration and incubation time. The direct antibacterial activity of chitosan may be attributed to membrane lysis evidenced by transmission electron microscopic observation. The disease index of watermelon seedlings planted in soil and the death rate of seedlings planted in perlite were significantly reduced by chitosan A at 0.40 mg mL⁻¹ compared to the pathogen control. Fresh and dry weight of watermelon seedlings planted in soil was increased by chitosan seed treatment, but not by chitosan leaf spraying. CONCLUSION: The results indicated that chitosan solution may have a potential in controlling bacterial fruit blotch of watermelon.


Assuntos
Agroquímicos/farmacologia , Antibacterianos/farmacologia , Quitosana/farmacologia , Citrullus/efeitos dos fármacos , Comamonadaceae/efeitos dos fármacos , Doenças das Plantas/prevenção & controle , Plântula/efeitos dos fármacos , Acetilação , Agroquímicos/química , Óxido de Alumínio , Antibacterianos/química , Membrana Celular/efeitos dos fármacos , Membrana Celular/ultraestrutura , China , Quitosana/química , Citrullus/enzimologia , Citrullus/crescimento & desenvolvimento , Citrullus/microbiologia , Contagem de Colônia Microbiana , Comamonadaceae/crescimento & desenvolvimento , Comamonadaceae/isolamento & purificação , Comamonadaceae/ultraestrutura , Frutas/efeitos dos fármacos , Frutas/enzimologia , Frutas/crescimento & desenvolvimento , Frutas/microbiologia , Testes de Sensibilidade Microbiana , Viabilidade Microbiana , Peso Molecular , Concentração Osmolar , Doenças das Plantas/microbiologia , Proteínas de Plantas/metabolismo , Plântula/enzimologia , Plântula/crescimento & desenvolvimento , Plântula/microbiologia , Sementes/efeitos dos fármacos , Sementes/enzimologia , Sementes/crescimento & desenvolvimento , Sementes/microbiologia , Dióxido de Silício , Solo
17.
Int J Syst Evol Microbiol ; 63(Pt 7): 2577-2582, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23291881

RESUMO

Five nitrogen-fixing bacterial strains (SP1(T), NN143, NN144, NN208 and HX148) were isolated from stem, root or rhizosphere soil of sugar cane (Saccharum officinarum L.) plants. Cells were Gram-negative, motile, rods with peritrichous flagella. DNA G+C content was 55.0 ± 0.5 mol%. Sequence determinations and phylogenetic analysis of 16S rRNA gene and rpoB indicated that the strains were affiliated with the genus Enterobacter and most closely related to E. radicincitans DSM 16656(T) and E. oryzae LMG 24251(T). Fluorimetric determination of thermal denaturation temperatures after DNA-DNA hybridization, enterobacterial repetitive intergenic consensus PCR and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry differentiated the whole-genome, genotype and protein profiles from those of E. radicincitans and E. oryzae. The strains' cell fatty acid composition differentiated them from E. radicincitans and E. oryzae by containing a higher level of summed feature 2 (C16 : 1ω7c and/or C16 : 1ω6c) and a lower level of C17 : 0 cyclo. Their physiological and biochemical profiles differentiated them from E. radicincitans by being positive for methyl red test, ornithine decarboxylase and utilization of putrescine, D-arabitol, L-fucose and methyl α-D-glucoside and being negative for arginine dihydrolase, and differentiated them from E. oryzae by being positive for aesculin hydrolysis and utilization of putrescine, D-arabitol and L-rhamnose and being negative for arginine dihydrolase, lysine decarboxylase and utilization of mucate. The five strains therefore represent a novel species, for which the name Enterobacter sacchari sp. nov. is proposed, with the type strain SP1(T) ( = CGMCC 1.12102(T) = LMG 26783(T)).


Assuntos
Enterobacter/classificação , Fixação de Nitrogênio , Filogenia , Saccharum/microbiologia , Proteínas de Bactérias/análise , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Enterobacter/genética , Enterobacter/isolamento & purificação , Ácidos Graxos/análise , Genes Bacterianos , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Raízes de Plantas/microbiologia , Caules de Planta/microbiologia , RNA Ribossômico 16S/genética , Rizosfera , Análise de Sequência de DNA
18.
Pest Manag Sci ; 69(2): 312-20, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23129534

RESUMO

BACKGROUND: Bacterial leaf blight and leaf streak are the two most damaging bacterial diseases of rice. However, few bactericidal chemicals are available for controlling both diseases. The antibacterial properties of two kinds of chitosan with different molecular weights and degrees of N-deacetylation and their effect on rice bacterial leaf blight and leaf streak were evaluated. RESULTS: Results showed that the two kinds of chitosan solution possess a strong antibacterial activity against both rice bacterial pathogens and significantly reduced disease incidence and severity by comparison with the control under greenhouse conditions. However, the interaction between chitosan and rice pathogens was affected by the type and concentration of chitosan, the bacterial species and the contact time between chitosan and bacteria. The direct antibacterial activity of chitosan may be attributed to both membrane lysis and the destruction of biofilm. In addition, both chitosan solutions significantly increased the activities of phenylalanine ammonia lyase, peroxidase and polyphenol oxidase in rice seedlings following inoculation of two rice pathogens by comparison with the control. CONCLUSION: The role of chitosan in protection of rice against bacterial pathogens has been shown to involve direct antibacterial activity and indirect induced resistance.


Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Quitosana/farmacologia , Oryza/microbiologia , Doenças das Plantas/microbiologia , Folhas de Planta/microbiologia
19.
PLoS One ; 7(11): e49657, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23166741

RESUMO

Outer membrane (OM) proteins play a significant role in bacterial pathogenesis. In this work, we examined and compared the expression of the OM proteins of the rice pathogen Acidovorax avenae subsp. avenae strain RS-1, a Gram-negative bacterium, both in an in vitro culture medium and in vivo rice plants. Global proteomic profiling of A. avenae subsp. avenae strain RS-1 comparing in vivo and in vitro conditions revealed the differential expression of proteins affecting the survival and pathogenicity of the rice pathogen in host plants. The shotgun proteomics analysis of OM proteins resulted in the identification of 97 proteins in vitro and 62 proteins in vivo by mass spectrometry. Among these OM proteins, there is a high number of porins, TonB-dependent receptors, lipoproteins of the NodT family, ABC transporters, flagellins, and proteins of unknown function expressed under both conditions. However, the major proteins such as phospholipase and OmpA domain containing proteins were expressed in vitro, while the proteins such as the surface anchored protein F, ATP-dependent Clp protease, OmpA and MotB domain containing proteins were expressed in vivo. This may indicate that these in vivo OM proteins have roles in the pathogenicity of A. avenae subsp. avenae strain RS-1. In addition, the LC-MS/MS identification of OmpA and MotB validated the in silico prediction of the existance of Type VI secretion system core components. To the best of our knowledge, this is the first study to reveal the in vitro and in vivo protein profiles, in combination with LC-MS/MS mass spectra, in silico OM proteome and in silico genome wide analysis, of pathogenicity or plant host required proteins of a plant pathogenic bacterium.


Assuntos
Proteínas da Membrana Bacteriana Externa/metabolismo , Comamonadaceae/metabolismo , Proteoma , Proteínas da Membrana Bacteriana Externa/genética , Sistemas de Secreção Bacterianos/genética , Cromatografia Líquida , Comamonadaceae/genética , Biologia Computacional/métodos , Regulação Bacteriana da Expressão Gênica , Ordem dos Genes , Estudo de Associação Genômica Ampla , Proteômica/métodos , Espectrometria de Massas em Tandem
20.
J Bacteriol ; 194(23): 6666-7, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23144410

RESUMO

Microbacterium barkeri strain 2011-R4 is a Gram-positive epiphyte which has been confirmed as a biocontrol agent against several plant pathogens in our previous studies. Here, we present the draft genome sequence of this strain, which was isolated from the rice rhizosphere in Tonglu city, Zhejiang province, China.


Assuntos
Actinomycetales/genética , DNA Bacteriano/química , DNA Bacteriano/genética , Genoma Bacteriano , Análise de Sequência de DNA , Actinomycetales/isolamento & purificação , Actinomycetales/fisiologia , Antibiose , China , Dados de Sequência Molecular , Oryza/microbiologia , Controle Biológico de Vetores/métodos , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Rizosfera
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA