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1.
Mar Drugs ; 17(8)2019 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-31357504

RESUMO

Candida albicans is a type of commensal fungi which causes serious infections in immunocompromised patients and contributes to high mortality. In the present study, we identified that the extract from Streptomyces olivaceus SCSIO T05 inhibited hypha and biofilm formation of C. albicans. Seven compounds were isolated and evaluated for their effects on the biological functions and virulence of C. albicans. Two leading compounds, compound 1 (sorbicillin) and compound 2 (3-methyl-N-(2'-phenethyl)-butyrylamide) were identified as exhibiting strong activity against C. albicans morphological transition, adhesion activity, cytotoxicity, and adhesion to human cells, in a dose-dependent manner. Notably, compound 2 inhibited C. albicans infection in mouse oral mucosal models. Transcriptomic analysis and real-time PCR results revealed that compound 2 most likely inhibited the biological functions of C. albicans cells by regulating the expression levels of HWP1, TEC1, ALS1, IFD6, and CSH1, which are associated with filament formation and cell adhesion. Our results suggest that the candidate compounds present excellent efficacy against C. albicans pathogenicity and that they can be developed as potential options for the clinical treatment of candidiasis.

2.
Appl Environ Microbiol ; 85(8)2019 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-30770405

RESUMO

Quorum sensing (QS) signals are widely used by bacterial pathogens to control biological functions and virulence in response to changes in cell population densities. Burkholderia cenocepacia employs a molecular mechanism in which the cis-2-dodecenoic acid (named Burkholderia diffusible signal factor [BDSF]) QS system regulates N-acyl homoserine lactone (AHL) signal production and virulence by modulating intracellular levels of cyclic diguanosine monophosphate (c-di-GMP). Thus, inhibition of BDSF signaling may offer a non-antibiotic-based therapeutic strategy against BDSF-regulated bacterial infections. In this study, we report the synthesis of small-molecule mimics of the BDSF signal and evaluate their ability to inhibit BDSF QS signaling in B. cenocepacia A novel structural analogue of BDSF, 14-Me-C16:Δ2 (cis-14-methylpentadec-2-enoic acid), was observed to inhibit BDSF production and impair BDSF-regulated phenotypes in B. cenocepacia, including motility, biofilm formation, and virulence, while it did not inhibit the growth rate of this pathogen. 14-Me-C16:Δ2 also reduced AHL signal production. Genetic and biochemical analyses showed that 14-Me-C16:Δ2 inhibited the production of the BDSF and AHL signals by decreasing the expression of their synthase-encoding genes. Notably, 14-Me-C16:Δ2 attenuated BDSF-regulated phenotypes in various Burkholderia species. These findings suggest that 14-Me-C16:Δ2 could potentially be developed as a new therapeutic agent against pathogenic Burkholderia species by interfering with their QS signaling.IMPORTANCE Burkholderia cenocepacia is an important opportunistic pathogen which can cause life-threatening infections in susceptible individuals, particularly in cystic fibrosis and immunocompromised patients. It usually employs two types of quorum sensing (QS) systems, including the cis-2-dodecenoic acid (BDSF) system and N-acyl homoserine lactone (AHL) system, to regulate virulence. In this study, we have designed and identified an unsaturated fatty acid compound (cis-14-methylpentadec-2-enoic acid [14-Me-C16:Δ2]) that is capable of interfering with B. cenocepacia QS signaling and virulence. We demonstrate that 14-Me-C16:Δ2 reduced BDSF and AHL signal production in B. cenocepacia It also impaired QS-regulated phenotypes in various Burkholderia species. These results suggest that 14-Me-C16:Δ2 could interfere with QS signaling in many Burkholderia species and might be developed as a new antibacterial agent.

3.
Artigo em Inglês | MEDLINE | ID: mdl-30675369

RESUMO

Pseudomonas aeruginosa tends to be among the dominant species in multi-species bacterial consortia in diverse environments. To understand P. aeruginosa's physiology and interactions with co-existing bacterial species in different conditions, we established physiologically reproducible 18 species communities, and found that P. aeruginosa dominated in mixed-species biofilm communities but not in planktonic communities. P. aeruginosa's H1 type VI secretion system was highly induced in mixed-species biofilm consortia, compared with its monospecies biofilm, which was further demonstrated to play a key role in P. aeruginosa's enhanced fitness over other bacterial species. In addition, the type IV pili and Psl exopolysaccharide were required for P. aeruginosa to compete with other bacterial species in the biofilm community. Our study showed that the physiology of P. aeruginosa is strongly affected by interspecies interactions, and both biofilm determinants and type VI secretion system contribute to higher P. aeruginosa's fitness over other species in complex biofilm communities.

4.
Artigo em Inglês | MEDLINE | ID: mdl-30670437

RESUMO

A rapid increase in Candida albicans infection and drug resistance has caused an emergent need for new clinical strategies against this fungal pathogen. In this study, we evaluated the inhibitory activity of a series of 2-alkylaminoquinoline derivatives against C. albicans isolates. A total of 28 compounds were assessed for their efficacy in inhibiting the yeast-to-hypha transition, which is considered one of the key virulence factors in C. albicans Several compounds showed strong activity to decrease the morphological transition and virulence of C. albicans cells. The two leading compounds, compound 1 (2-[piperidin-1-yl]quinolone) and compound 12 (6-methyl-2-[piperidin-1-yl]quinoline), remarkably attenuated C. albicans hyphal formation and cytotoxicity in a dose-dependent manner, but they showed no toxicity to either C. albicans cells or human cells. Intriguingly, compound 12 showed an excellent ability to inhibit C. albicans infection in the mouse oral mucosal infection model. This leading compound also interfered with the expression levels of hypha-specific genes in the cyclic AMP-protein kinase A and mitogen-activated protein kinase signaling pathways. Our findings suggest that 2-alkylaminoquinoline derivatives could potentially be developed as novel therapeutic agents against C. albicans infection due to their interference with the yeast-to-hypha transition.

5.
Org Lett ; 21(1): 218-222, 2019 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-30571132

RESUMO

A cobalt-catalyzed site-selective functionalization of aniline derivatives with hexafluoroisopropanol, which enables the synthesis of a wide array of fluoroalkylated anilines, a class of highly valuable building blocks for further preparation of fluorinated functional products, is reported. The developed transformation proceeds with operational simplicity, use of earth-abundant metal catalyst, broad substrate scope, good functional group tolerance, and mild reaction conditions.

6.
J Agric Food Chem ; 67(1): 112-119, 2019 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-30543296

RESUMO

The morphological changes from single-cell yeast to filamentous hypha form are critical in plant pathogenic smut fungi. This dimorphic switch is tightly regulated by complex gene pathways in pathogenic development. The phytopathogenic basidiomycetes Sporisorium scitamineum displays a morphological transition from budding growth of haploid cells to filamentous growth of the dikaryon, which enables fungi to forage for nutrients and evade the host plant immune system. In the search for compounds that affect dimorphic switch instead of killing the cell directly, a natural product, mycophenolic acid (MPA), was purified and exhibited significant dimorphism inhibitory activities with minimum effective concentrations of 0.3 µg/mL. RNA sequencing and real-time quantitative transcription-PCR analysis showed that treatment of 100 µg/mL MPA dramatically repressed the expression of the ammonium transporter gene Ssa2 . A further subcellular localization experiment, ammonium response assay, and Western blot assay confirmed that Ssa2 could be one of the most important molecular targets of MPA in regulating dimorphism of S. scitamineum. These observations suggest that Ssa2 serves as a molecular target of MPA and could be used in the treatment of sugar cane smut diseases caused by S. scitamineum.


Assuntos
Basidiomycota/efeitos dos fármacos , Basidiomycota/crescimento & desenvolvimento , Fungicidas Industriais/farmacologia , Ácido Micofenólico/farmacologia , Doenças das Plantas/microbiologia , Saccharum/microbiologia , Basidiomycota/genética , Basidiomycota/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Fungicidas Industriais/química , Ácido Micofenólico/química , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/crescimento & desenvolvimento
7.
Microb Biotechnol ; 11(6): 1080-1089, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30221456

RESUMO

Clinical treatment of Candida albicans infections has become more difficult due to the limited development of antifungal agents and the rapid emergence of drug resistance. In this study, we demonstrate the synthesis of a series of piperazine derivatives and the evaluation of their inhibitory activity against C. albicans virulence. Thirty-four (1-aryloxy-2-hydroxypropyl)-phenylpiperazine derivatives, including 25 new compounds, were synthesized and assessed for their efficacy against the physiology and pathogenesis of C. albicans. Several compounds strongly inhibited the morphological transition and virulence of C. albicans cells, although they did not influence the growth rate of the fungal pathogen. A leading novel compound, (1-(4-ethoxyphenyl)-4-(1-biphenylol-2-hydroxypropyl)-piperazine), significantly attenuated C. albicans virulence by interfering with the process of hyphal development, but it showed no cytotoxicity against human cells at a micromolar level. These findings suggest that (1-aryloxy-2-hydroxypropyl)-phenylpiperazine derivatives could potentially be developed as novel therapeutic agents for the clinical treatment of C. albicans infections by interfering with morphological transition and virulence.

8.
Mol Plant Microbe Interact ; : MPMI07180187R, 2018 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-30156480

RESUMO

The plant pathogen Xanthomonas campestris pv. campestris produces diffusible signal factor (DSF) quorum sensing (QS) signals to regulate its biological functions and virulence. Our previous study showed that X. campestris pv. campestris utilizes host plant metabolites to enhance the biosynthesis of DSF family signals. However, it is unclear how X. campestris pv. campestris benefits from the metabolic products of the host plant. In this study, we observed that the host plant metabolites not only boosted the production of the DSF family signals but also modulated the expression levels of DSF-regulated genes in X. campestris pv. campestris. Infection with X. campestris pv. campestris induced changes in the expression of many sugar transporter genes in Arabidopsis thaliana. Exogenous addition of sucrose or glucose, which are the major products of photosynthesis in plants, enhanced DSF signal production and X. campestris pv. campestris pathogenicity in the Arabidopsis model. In addition, several sucrose hydrolase-encoding genes in X. campestris pv. campestris and sucrose invertase-encoding genes in the host plant were notably upregulated during the infection process. These enzymes hydrolyzed sucrose to glucose and fructose, and in trans expression of one of these enzymes, CINV1 of A. thaliana or XC_0805 of X. campestris pv. campestris, enhanced DSF signal biosynthesis in X. campestris pv. campestris in the presence of sucrose. Taken together, our findings demonstrate that X. campestris pv. campestris applies multiple strategies to utilize host plant sugars to enhance QS and pathogenicity.

9.
Molecules ; 23(1)2018 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-29351264

RESUMO

Ralstonia solanacearum is a causative agent of bacterial wilt in many important crops throughout the world. How to control bacterial wilt caused by R. solanacearum is a major problem in agriculture. In this study, we aim to isolate the biocontrol agents that have high efficacy in the control of bacterial wilt. Three new bacterial strains with high antimicrobial activity against R. solanacearum GMI1000 were isolated and identified. Our results demonstrated that these bacteria could remarkably inhibit the disease index of host plant infected by R. solanacearum. It was indicated that strain GZ-34 (CCTCC No. M 2016353) showed an excellent protective effect to tomato under greenhouse conditions. Strain GZ-34 was characterized as Escherichia coli based on morphology, biochemistry, and 16S rRNA analysis. We identified that the main antimicrobial compounds produced by E. coli GZ-34 were cyclo(l-Pro-d-Ile) and cyclo(l-Pro-l-Phe) using electrospray ionization mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR) analysis. The two active compounds also interfered with the expression levels of some pathogenicity-contributors of R. solanacearum. Furthermore, cyclo(l-Pro-l-Phe) effectively inhibited spore formation of Magnaporthe grisea, which is a vital pathogenesis process of the fungal pathogen, suggesting cyclic dipeptides from E. coli are promising potential antimicrobial agents with broad-spectrum activity to kill pathogens or interfere with their pathogenesis.


Assuntos
Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Antibiose , Dipeptídeos/química , Escherichia coli/metabolismo , Peptídeos Cíclicos/química , Ralstonia solanacearum/efeitos dos fármacos , Anti-Infecciosos/isolamento & purificação , Dipeptídeos/isolamento & purificação , Dipeptídeos/farmacologia , Escherichia coli/isolamento & purificação , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Peptídeos Cíclicos/isolamento & purificação , Peptídeos Cíclicos/farmacologia , Plantas/microbiologia , Microbiologia do Solo , Espectrometria de Massas por Ionização por Electrospray
10.
Mol Microbiol ; 108(1): 32-44, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29363827

RESUMO

Quorum sensing (QS) is widely utilized by bacterial pathogens to regulate biological functions and pathogenicity. Recent evidence has shown that QS is subject to regulatory cascades, especially two-component systems that often respond to environmental stimulation. At least two different types of QS systems regulate pathogenesis in Burkholderia cenocepacia. However, it remains unclear how this bacterial pathogen controls these QS systems. Here, we demonstrate a novel two-component system RqpSR (Regulating Quorum sensing and Pathogenicity), which plays an important role in modulating QS and pathogenesis in B. cenocepacia. We demonstrate strong protein-protein binding affinity between RqpS and RqpR. Mutations in rqpS and rqpR exerted overlapping effects on B. cenocepacia transcriptomes and phenotypes, including motility, biofilm formation and virulence. In trans expression of rqpR rescued the defective phenotypes in the rqpS mutant. RqpR controls target gene expression by direct binding to DNA promoters, including the cis-2-dodecenoic acid (BDSF) and N-acylhomoserine lactone (AHL) signal synthase gene promoters. These findings suggest that the RqpSR system strongly modulates physiology by forming a complicated hierarchy with QS systems. This type of two-component system appears to be widely distributed and coexists with the BDSF QS system in various bacterial species.

11.
Proc Natl Acad Sci U S A ; 114(49): 13006-13011, 2017 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-29158389

RESUMO

Quorum sensing (QS) signals are used by bacteria to regulate biological functions in response to cell population densities. Cyclic diguanosine monophosphate (c-di-GMP) regulates cell functions in response to diverse environmental chemical and physical signals that bacteria perceive. In Burkholderia cenocepacia, the QS signal receptor RpfR degrades intracellular c-di-GMP when it senses the QS signal cis-2-dodecenoic acid, also called Burkholderia diffusible signal factor (BDSF), as a proxy for high cell density. However, it was unclear how this resulted in control of BDSF-regulated phenotypes. Here, we found that RpfR forms a complex with a regulator named GtrR (BCAL1536) to enhance its binding to target gene promoters under circumstances where the BDSF signal binds to RpfR to stimulate its c-di-GMP phosphodiesterase activity. In the absence of BDSF, c-di-GMP binds to the RpfR-GtrR complex and inhibits its ability to control gene expression. Mutations in rpfR and gtrR had overlapping effects on both the B. cenocepacia transcriptome and BDSF-regulated phenotypes, including motility, biofilm formation, and virulence. These results show that RpfR is a QS signal receptor that also functions as a c-di-GMP sensor. This protein thus allows B. cenocepacia to integrate information about its physical and chemical surroundings as well as its population density to control diverse biological functions including virulence. This type of QS system appears to be widely distributed in beta and gamma proteobacteria.


Assuntos
Proteínas de Bactérias/genética , Burkholderia cenocepacia/genética , Burkholderia cenocepacia/patogenicidade , GMP Cíclico/análogos & derivados , Ácidos Graxos Monoinsaturados/metabolismo , Regulação Bacteriana da Expressão Gênica , Percepção de Quorum/genética , Animais , Carga Bacteriana , Proteínas de Bactérias/metabolismo , Biofilmes/crescimento & desenvolvimento , Infecções por Burkholderia/microbiologia , Infecções por Burkholderia/patologia , Burkholderia cenocepacia/crescimento & desenvolvimento , GMP Cíclico/metabolismo , Camundongos , Mutação , Fenótipo , Transdução de Sinais , Virulência
12.
Front Microbiol ; 8: 1172, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28690607

RESUMO

Ralstonia solanacearum is a ubiquitous soil-borne plant pathogenic bacterium, which frequently encounters and interacts with other soil cohabitants in competition for environmental niches. Ralsolamycin, which is encoded by the rmy genes, has been characterized as a novel inter-kingdom interaction signal that induces chlamydospore development in fungi. In this study, we provide the first genetic evidence that the rmy gene expression is controlled by the PhcBSR quorum sensing (QS) system in strain GMI1000. Mutation of phcB could lead to significant reduction of the expression levels of the genes involved in ralsolamycin biosynthesis. In addition, both the phcB and rmy mutants were attenuated in induction of chlamydospore formation in Fusarium oxysporum f. cubense and diminished in the ability to compete with the sugarcane pathogen Sporisorium scitamineum. Agreeable with the pattern of QS regulation, transcriptional expression analysis showed that the transcripts of the rmy genes were increased along with the increment of the bacterial population density. Taken together, the above findings provide new insights into the regulatory mechanisms that the QS system involves in governing the ralsolamycin inter-kingdom signaling system.

13.
Mar Drugs ; 14(12)2016 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-27999388

RESUMO

Cytoglobosins H (1) and I (2), together with seven known cytochalasan alkaloids (3-9), were isolated from the deep-sea-derived fungus Chaetomium globosum. The structures of new compounds 1 and 2 were elucidated by extensive 1D and 2D NMR and mass spectroscopic data. All the compounds were evaluated for their antiproliferative activities against MDA-MB-231 human breast cancer cells, LNCaP human prostate cancer cells, and B16F10 mouse melanoma cells. Compound 6 showed significant antiproliferative activity against LNCaP and B16F10 cell lines with IC50 values of 0.62 and 2.78 µM, respectively. Further testing confirmed that compound 6 inhibited the growth of LNCaP cells by inducing apoptosis.


Assuntos
Antineoplásicos/química , Chaetomium/química , Alcaloides Indólicos/química , Animais , Antineoplásicos/isolamento & purificação , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Chaetomium/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Ensaios de Seleção de Medicamentos Antitumorais , Fermentação , Humanos , Alcaloides Indólicos/isolamento & purificação , Alcaloides Indólicos/farmacologia , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Camundongos , Extração em Fase Sólida
14.
Front Microbiol ; 7: 1719, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27833603

RESUMO

Ralstonia solanacearum species complex is a devastating group of phytopathogens with an unusually wide host range and broad geographical distribution. R. solanacearum isolates may differ considerably in various properties including host range and pathogenicity, but the underlying genetic bases remain vague. Here, we conducted the genome sequencing of strain EP1 isolated from Guangdong Province of China, which belongs to phylotype I and is highly virulent to a range of solanaceous crops. Its complete genome contains a 3.95-Mb chromosome and a 2.05-Mb mega-plasmid, which is considerably bigger than reported genomes of other R. solanacearum strains. Both the chromosome and the mega-plasmid have essential house-keeping genes and many virulence genes. Comparative analysis of strain EP1 with other 3 phylotype I and 3 phylotype II, III, IV strains unveiled substantial genome rearrangements, insertions and deletions. Genome sequences are relatively conserved among the 4 phylotype I strains, but more divergent among strains of different phylotypes. Moreover, the strains exhibited considerable variations in their key virulence genes, including those encoding secretion systems and type III effectors. Our results provide valuable information for further elucidation of the genetic basis of diversified virulences and host range of R. solanacearum species.

15.
J Biol Chem ; 291(31): 16112-23, 2016 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-27231351

RESUMO

The bacterial messenger cyclic di-GMP (c-di-GMP) binds to a diverse range of effectors to exert its biological effect. Despite the fact that free-standing PilZ proteins are by far the most prevalent c-di-GMP effectors known to date, their physiological function and mechanism of action remain largely unknown. Here we report that the free-standing PilZ protein PA2799 from the opportunistic pathogen Pseudomonas aeruginosa interacts directly with the hybrid histidine kinase SagS. We show that PA2799 (named as HapZ: histidine kinase associated PilZ) binds directly to the phosphoreceiver (REC) domain of SagS, and that the SagS-HapZ interaction is further enhanced at elevated c-di-GMP concentration. We demonstrate that binding of HapZ to SagS inhibits the phosphotransfer between SagS and the downstream protein HptB in a c-di-GMP-dependent manner. In accordance with the role of SagS as a motile-sessile switch and biofilm growth factor, we show that HapZ impacts surface attachment and biofilm formation most likely by regulating the expression of a large number of genes. The observations suggest a previously unknown mechanism whereby c-di-GMP mediates two-component signaling through a PilZ adaptor protein.


Assuntos
Proteínas de Bactérias/metabolismo , Biofilmes/crescimento & desenvolvimento , GMP Cíclico/análogos & derivados , Histidina Quinase/metabolismo , Pseudomonas aeruginosa/fisiologia , Sistemas do Segundo Mensageiro/fisiologia , Proteínas de Bactérias/genética , GMP Cíclico/genética , GMP Cíclico/metabolismo , Histidina Quinase/genética
16.
Environ Microbiol ; 18(5): 1534-45, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-26913592

RESUMO

Diffusible signal factor (DSF) represents a new class of widely conserved quorum sensing signals, which regulates various biological functions through intra- or interspecies signaling. The previous studies identified that there is an antagonistic interaction between Xanthomonas and Bacillus species bacteria in natural ecosystem, but the detailed molecular mechanism of interspecies competition is not clear. This study showed that Xanthomonas campestris pv. campestris (Xcc) interfered with morphological transition and sporulation of Bacillus thuringiensis in mixed cultures, whereas abrogation of the DSF synthase RpfF reduced the interference. DSF inhibited B. thuringiensis cell division and sporulation through modulation of ftsZ, which encodes an important cell division protein in bacterial cells. In addition, RpfF is essential for production of six DSF-family signals in Xcc, which employ the same signaling pathways to regulate biological functions in Xcc and play similar effects on reduction of cell division, sporulation and antibiotic resistance of B. thuringiensis. Furthermore, abrogation of RpfF decreased the competitive capability of Xcc against B. thuringiensis on the surface of Chinese cabbage leaves. Our findings provide new insights into the role of DSF-family signals in interspecies competition and depict molecular mechanisms with which Xcc competes with B. thuringiensis.


Assuntos
Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica/fisiologia , Aptidão Genética , Xanthomonas campestris/metabolismo , Proteínas de Bactérias/genética , Difusão , Percepção de Quorum , Transdução de Sinais , Xanthomonas campestris/genética
17.
Sci Rep ; 5: 8784, 2015 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-25740758

RESUMO

Cyhalothrin is a common environmental pollutant which poses increased risks to non-target organisms including human beings. This study reported for the first time a newly isolated strain, Bacillus thuringiensis ZS-19 completely degraded cyhalothrin in minimal medium within 72 h. The bacterium transformed cyhalothrin by cleavage of both the ester linkage and diaryl bond to yield six intermediate products. Moreover, a novel degradation pathway of cyhalothrin in strain ZS-19 was proposed on the basis of the identified metabolites. In addition to degradation of cyhalothrin, this strain was found to be capable of degrading 3-phenoxybenzoic acid, a common metabolite of pyrethroids. Furthermore, strain ZS-19 participated in efficient degradation of a wide range of pyrethroids including cyhalothrin, fenpropathrinn, deltamethrin, beta-cypermethrin, cyfluthrin and bifenthrin. Taken together, our results provide insights into the mechanism of cyhalothrin degradation and also highlight the promising potentials of B.thuringiensis ZS-19 in bioremediation of pyrethroid-contaminated environment. This is the first report of (i) degradation of cyhalothrin and other pyrethroids by B.thuringiensis, (ii) identification of 3-phenoxyphenyl acetonitrile and N-(2-isoproxy-phenyl)-4-phenoxy-benzamide as the metabolites in the degradation pathway of pyrethroids, and (iii) a pathway of degradation of cyhalothrin by cleavage of both the ester linkage and diaryl bond in a microorganism.


Assuntos
Bacillus thuringiensis/metabolismo , Biodegradação Ambiental , Fungicidas Industriais/metabolismo , Redes e Vias Metabólicas , Nitrilos/metabolismo , Piretrinas/metabolismo , Bacillus thuringiensis/classificação , Bacillus thuringiensis/genética , Bacillus thuringiensis/isolamento & purificação , Benzoatos/metabolismo , Cinética , Metaboloma , Metabolômica/métodos , Filogenia , RNA Ribossômico 16S/genética
18.
Appl Environ Microbiol ; 81(8): 2861-8, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25681189

RESUMO

Plant pathogen Xanthomonas campestris pv. campestris produces cis-11-methyl-2-dodecenoic acid (diffusible signal factor [DSF]) as a cell-cell communication signal to regulate biofilm dispersal and virulence factor production. Previous studies have demonstrated that DSF biosynthesis is dependent on the presence of RpfF, an enoyl-coenzyme A (CoA) hydratase, but the DSF synthetic mechanism and the influence of the host plant on DSF biosynthesis are still not clear. We show here that exogenous addition of host plant juice or ethanol extract to the growth medium of X. campestris pv. campestris could significantly boost DSF family signal production. It was subsequently revealed that X. campestris pv. campestris produces not only DSF but also BDSF (cis-2-dodecenoic acid) and another novel DSF family signal, which was designated DSF-II. BDSF was originally identified in Burkholderia cenocepacia to be involved in regulation of motility, biofilm formation, and virulence in B. cenocepacia. Functional analysis suggested that DSF-II plays a role equal to that of DSF in regulation of biofilm dispersion and virulence factor production in X. campestris pv. campestris. Furthermore, chromatographic separation led to identification of glucose as a specific molecule stimulating DSF family signal biosynthesis in X. campestris pv. campestris. (13)C-labeling experiments demonstrated that glucose acts as a substrate to provide a carbon element for DSF biosynthesis. The results of this study indicate that X. campestris pv. campestris could utilize a common metabolite of the host plant to enhance DSF family signal synthesis and therefore promote virulence.


Assuntos
Proteínas de Bactérias/genética , Biofilmes/crescimento & desenvolvimento , Glucose/metabolismo , Transdução de Sinais , Fatores de Virulência/genética , Xanthomonas campestris/fisiologia , Proteínas de Bactérias/metabolismo , Brassica rapa/química , Reação em Cadeia da Polimerase em Tempo Real , Xanthomonas campestris/genética
19.
BMC Microbiol ; 14: 51, 2014 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-24575808

RESUMO

BACKGROUND: Extensive use of antibiotics has fostered the emergence of superbugs that are resistant to multidrugs, which becomes a great healthcare and public concern. Previous studies showed that quorum sensing signal DSF (diffusible signal factor) not only modulates bacterial antibiotic resistance through intraspecies signaling, but also affects bacterial antibiotic tolerance through interspecies communication. These findings motivate us to exploit the possibility of using DSF and its structurally related molecules as adjuvants to influence antibiotic susceptibility of bacterial pathogens. RESULTS: In this study, we have demonstrated that DSF signal and its structurally related molecules could be used to induce bacterial antibiotic susceptibility. Exogenous addition of DSF signal (cis-11-methyl-2-dodecenoic acid) and its structural analogues could significantly increase the antibiotic susceptibility of Bacillus cereus, possibly through reducing drug-resistant activity, biofilm formation and bacterial fitness. The synergistic effect of DSF and its structurally related molecules with antibiotics on B. cereus is dosage-dependent. Combination of DSF with gentamicin showed an obviously synergistic effect on B. cereus pathogenicity in an in vitro model. We also found that DSF could increase the antibiotic susceptibility of other bacterial species, including Bacillus thuringiensis, Staphylococcus aureus, Mycobacterium smegmatis, Neisseria subflava and Pseudomonas aeruginosa. CONCLUSION: The results indicate a promising potential of using DSF and its structurally related molecules as novel adjuvants to conventional antibiotics for treatment of infectious diseases caused by bacterial pathogens.


Assuntos
Antibacterianos/farmacologia , Sinergismo Farmacológico , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Ácidos Láuricos/farmacologia , Relação Dose-Resposta a Droga , Gentamicinas/farmacologia , Bactérias Gram-Negativas/fisiologia , Bactérias Gram-Positivas/fisiologia , Humanos , Percepção de Quorum
20.
J Agric Food Chem ; 62(10): 2147-57, 2014 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-24576059

RESUMO

The widely used insecticide fenpropathrin in agriculture has become a public concern because of its heavy environmental contamination and toxic effects on mammals, yet little is known about the kinetic and metabolic behaviors of this pesticide. This study reports the degradation kinetics and metabolic pathway of fenpropathrin in Bacillus sp. DG-02, previously isolated from the pyrethroid-manufacturing wastewater treatment system. Up to 93.3% of 50 mg L(-1) fenpropathrin was degraded by Bacillus sp. DG-02 within 72 h, and the degradation rate parameters qmax, Ks, and Ki were determined to be 0.05 h(-1), 9.0 mg L(-1), and 694.8 mg L(-1), respectively. Analysis of the degradation products by gas chromatography-mass spectrometry led to identification of seven metabolites of fenpropathrin, which suggest that fenpropathrin could be degraded first by cleavage of its carboxylester linkage and diaryl bond, followed by degradation of the aromatic ring and subsequent metabolism. In addition to degradation of fenpropathrin, this strain was also found to be capable of degrading a wide range of synthetic pyrethroids including deltamethrin, λ-cyhalothrin, ß-cypermethrin, ß-cyfluthrin, bifenthrin, and permethrin, which are also widely used insecticides with environmental contamination problems with the degradation process following the first-order kinetic model. Bioaugmentation of fenpropathrin-contaminated soils with strain DG-02 significantly enhanced the disappearance rate of fenpropathrin, and its half-life was sharply reduced in the soils. Taken together, these results depict the biodegradation mechanisms of fenpropathrin and also highlight the promising potentials of Bacillus sp. DG-02 in bioremediation of pyrethroid-contaminated soils.


Assuntos
Bacillus/metabolismo , Inseticidas/metabolismo , Piretrinas/metabolismo , Poluentes do Solo/metabolismo , Bacillus/crescimento & desenvolvimento , Biodegradação Ambiental , Cromatografia Gasosa-Espectrometria de Massas , Cinética
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