Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.420
Filtrar
1.
Int J Food Microbiol ; 330: 108783, 2020 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-32659523

RESUMO

The contamination of Aspergillus carbonarius causes decreases and great decay of agricultural products, and threatens the human and animal health by producing mycotoxins, especially ochratoxin A. Bacillus subtilis has been proved to efficiently inhibit the growth of A. carbonarius. Revealing the major active compound and the mechanisms for the antifungal of B. subtilis are essential to enhance its antifungal activity and control the quality of antifungal products made of it. In this study, we determined that iturin A is the major compound that inhibits Aspergillus carbonarius, a widespread fungal pathogen of grape and other fruits. Iturin A significantly inhibited growth and ochratoxin A production of A. carbonarius with minimal inhibitory concentrations (MICs) of 10 µg/mL and 0.312 µg/mL, respectively. Morphological observations revealed that iturin A caused swelling of the fungal cells and thinning of the cell wall and membrane at 1/2 MIC, whereas it inhibited fungal spore germination and caused mitochondrial swelling at higher concentrations. A differential transcriptomic analysis indicated that the mechanisms used by iturin A to inhibit A. carbonarius were to downregulate the expression of genes related to cell membrane, transport, osmotic pressure, oxidation-reduction processes, and energy metabolism. Among the down-regulated genes, those related to the transport capacity were most significantly influenced, including the increase of energy-related transport pathways and decrease of other pathways. Notably, the genes related to taurine and hypotaurine metabolism were also decreased, indicating iturin A potentially cause the occurrence of osmotic imbalance in A. carbonarius, which may be the intrinsic cause for the swelling of fungal cells and mitochondria. Overall, iturin A produced by B. subtilis played important roles to inhibit A. carbonarius via changing the fungal cell structure and causing perturbations to energy, transport and osmotic pressure metabolisms in fungi. The results indicated a new direction for researches on the mechanisms for lipopeptides and provided useful information to develop more efficient antifungal agents, which are important to agriculture and biomedicine.


Assuntos
Antifúngicos/farmacologia , Aspergillus/efeitos dos fármacos , Aspergillus/metabolismo , Bacillus subtilis/metabolismo , Peptídeos Cíclicos/farmacologia , Antifúngicos/metabolismo , Aspergillus/genética , Aspergillus/crescimento & desenvolvimento , Transporte Biológico/efeitos dos fármacos , Transporte Biológico/genética , Metabolismo Energético/efeitos dos fármacos , Metabolismo Energético/genética , Regulação Fúngica da Expressão Gênica/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Micotoxinas/metabolismo , Pressão Osmótica/efeitos dos fármacos , Peptídeos Cíclicos/metabolismo , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/metabolismo , Transcriptoma
2.
AAPS PharmSciTech ; 21(5): 172, 2020 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-32533366

RESUMO

Dissolution testing and solubility determinations in different biorelevant media have gained considerable interest in the pharmaceutical industry from early-stage development of new products to forecasting bioequivalence. Among all biorelevant fluids, the preparation of fed-state simulated gastric fluid (FeSSGF) and handling of samples from dissolution/solubility testing in FeSSGF is considered to be relatively challenging. Challenges include maintaining the stability of FeSSGF medium upon sampling, filtration, and mitigating analytical interference of excipients and milk components. To overcome these challenges, standard and uniform working practices are required that are not only helpful in preparation of stable FeSSGF but also serve as a harmonizing guide for the collection of dissolution/solubility samples and their subsequent processing (i.e., handling and assay). The optimization of sample preparation methodology is crucial to reduce method-related variance by ensuring specificity, robustness, and reproducibility with acceptable recovery of the analytes. The sample preparation methodology includes a combination of techniques including filtration, solvent treatment, and centrifugation to remove the interfering media-related components and excipients from the analyte. The analytes of interest were chromatographically separated from the interfering analytes to quantify the drug concentration using the new high-performance liquid chromatography methods with ultraviolet detection. The methods developed allow rapid sample preparation, acceptable specificity, reproducible recoveries (greater than 95% of label claim), and quantification of study drugs (ibuprofen and ketoconazole). The sample preparation technique and method considerations provided here for ibuprofen and ketoconazole can serve as a starting point for solubility and dissolution testing of other small molecules in FeSSGF.


Assuntos
Desenvolvimento de Medicamentos/métodos , Ácido Gástrico/metabolismo , Ibuprofeno/metabolismo , Cetoconazol/metabolismo , Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/metabolismo , Antifúngicos/química , Antifúngicos/metabolismo , Cromatografia Líquida de Alta Pressão/métodos , Ibuprofeno/química , Cetoconazol/química , Reprodutibilidade dos Testes , Solubilidade , Comprimidos
4.
PLoS Pathog ; 16(4): e1008518, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32324832

RESUMO

Competition is one of the fundamental driving forces of natural selection. Beauveria bassiana is a soil and plant phylloplane/root fungus capable of parasitizing insect hosts. Soil and plant environments are often enriched with other fungi against which B. bassiana competes for survival. Here, we report an antifungal peptide (BbAFP1), specifically expressed and localized to the conidial cell wall and is released into the surrounding microenvironment inhibiting growth of competing fungi. B. bassiana strains expressing BbAFP1, including overexpression strains, inhibited growth of Alternaria brassicae in co-cultured experiments, whereas targeted gene deletion of BbAFP1 significantly decreased (25%) this inhibitory effect. Recombinant BbAFP1 showed chitin and glucan binding abilities, and growth inhibition of a wide range of phytopathogenic fungi by disrupting membrane integrity and eliciting reactive oxygen species (ROS) production. A phenylalanine residue (F50) contributes to chitin binding and antifungal activity, but was not required for the latter. Expression of BbAFP1 in tomato resulted in transgenic plants with enhanced resistance to plant fungal pathogens. These results highlight the importance of fungal competition in shaping primitive competition strategies, with antimicrobial compounds that can be embedded in the spore cell wall to be released into the environment during the critical initial phases of germination for successful growth in its environmental niche. Furthermore, these peptides can be exploited to increase plant resistance to fungal pathogens.


Assuntos
Antifúngicos/metabolismo , Beauveria/metabolismo , Esporos Fúngicos/metabolismo , Animais , Antifúngicos/farmacologia , Beauveria/genética , Parede Celular/metabolismo , Quitina/metabolismo , Proteínas Fúngicas/metabolismo , Glucanos/metabolismo , Insetos/microbiologia , Peptídeos , Raízes de Plantas/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Espécies Reativas de Oxigênio , Estresse Fisiológico/efeitos dos fármacos , Virulência
5.
J Appl Microbiol ; 129(3): 652-664, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32196866

RESUMO

AIMS: This study aimed to apply the volatile organic compounds from Streptomyces philanthi RL-1-178 (VOCs RL-1-178) as a fumigant to protect soybean seeds against the two aflatoxin-producing fungi in stored soybean seeds. METHODS AND RESULTS: The antifungal bioassay tests on potato dextrose agar (PDA) dishes showed that 30 g l-1 wheat seed inoculum of S. philanthi RL-1-178 exhibited total (100%) inhibition on Aspergillus parasiticus TISTR 3276 and Aspergillus flavus PSRDC-4. Identification of the VOCs RL-1-178 using GC-MS revealed 39 compounds with the most abundant substances being geosmin (13·75%) followed by l-linalool (13·55%), 2-mercaptoethanol (9·71%) and heneicosane (5·96%). Comparison on the efficacy of the VOCs RL-1-178 (at 30 g l-1 wheat seed culture) and their four major components (100 µl l-1 each) on the suppression of the two aflatoxin-producing fungi on PDA plates revealed that the VOCs RL-1-178 as well as geosmin, l-linalool and 2-mercaptoethanol completely inhibited (100%) mycelial growth while heneicosane showed only 70·7% inhibition. Use of the VOCs RL-1-178 (30 g l-1 ) as a biofumigant on stored soybean seeds resulted in complete protection (100%) against the infection as well as complete inhibition on production of aflatoxin (B1 , B2 and G2 ) (analysed by HPLC) by the two aflatoxin-producing fungi. CONCLUSIONS: The VOCs RL-1-178 displayed strong inhibitory effects on A. parasiticus TISTR 3276 and A. flavus PSRDC-4 as well as inhibited aflatoxin (B1 , B2 and G2 ) production. SIGNIFICANCE AND IMPACT OF THE STUDY: These findings suggest that the VOCs RL-1-178 can be applied as a biofumigant to control the two aflatoxin-producing fungi on stored seeds products.


Assuntos
Aspergillus/efeitos dos fármacos , Fumigação/métodos , Controle Biológico de Vetores/métodos , Soja/microbiologia , Streptomyces/metabolismo , Aflatoxinas/biossíntese , Antifúngicos/metabolismo , Antifúngicos/farmacologia , Aspergillus/crescimento & desenvolvimento , Aspergillus/metabolismo , Sementes/microbiologia
6.
Appl Environ Microbiol ; 86(10)2020 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-32144106

RESUMO

In Lysobacter enzymogenes OH11, RpfB1 and RpfB2 were predicted to encode acyl coenzyme A (CoA) ligases. RpfB1 is located in the Rpf gene cluster. Interestingly, we found an RpfB1 homolog (RpfB2) outside this canonical gene cluster, and nothing is known about its functionality or mechanism. Here, we report that rpfB1 and rpfB2 can functionally replace EcFadD in the Escherichia coli fadD mutant JW1794. RpfB activates long-chain fatty acids (n-C16:0 and n-C18:0) for the corresponding fatty acyl-CoA ligase (FCL) activity in vitro, and Glu-361 plays critical roles in the catalytic mechanism of RpfB1 and RpfB2. Deletion of rpfB1 and rpfB2 resulted in significantly increased heat-stable antifungal factor (HSAF) production, and overexpression of rpfB1 or rpfB2 completely suppressed HSAF production. Deletion of rpfB1 and rpfB2 resulted in increased L. enzymogenes diffusible signaling factor 3 (LeDSF3) synthesis in L. enzymogenes Overall, our results showed that changes in intracellular free fatty acid levels significantly altered HSAF production. Our report shows that intracellular free fatty acids are required for HSAF production and that RpfB affects HSAF production via FCL activity. The global transcriptional regulator Clp directly regulated the expression of rpfB1 and rpfB2 In conclusion, these findings reveal new roles of RpfB in antibiotic biosynthesis in L. enzymogenes IMPORTANCE Understanding the biosynthetic and regulatory mechanisms of heat-stable antifungal factor (HSAF) could improve the yield in Lysobacter enzymogenes Here, we report that RpfB1 and RpfB2 encode acyl coenzyme A (CoA) ligases. Our research shows that RpfB1 and RpfB2 affect free fatty acid metabolism via fatty acyl-CoA ligase (FCL) activity to reduce the substrate for HSAF synthesis and, thereby, block HSAF production in L. enzymogenes Furthermore, these findings reveal new roles for the fatty acyl-CoA ligases RpfB1 and RpfB2 in antibiotic biosynthesis in L. enzymogenes Importantly, the novelty of this work is the finding that RpfB2 lies outside the Rpf gene cluster and plays a key role in HSAF production, which has not been reported in other diffusible signaling factor (DSF)/Rpf-producing bacteria.


Assuntos
Antifúngicos/metabolismo , Proteínas de Bactérias/genética , Coenzima A Ligases/genética , Lysobacter/genética , Sequência de Aminoácidos , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Coenzima A Ligases/química , Coenzima A Ligases/metabolismo , Ácidos Graxos não Esterificados/metabolismo , Lysobacter/metabolismo , Oxirredução , Alinhamento de Sequência
7.
J Biosci Bioeng ; 130(1): 6-13, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32192842

RESUMO

Defensins are antibacterial peptides that function in the innate immune system. OsAFP1, a defensin identified from Oryza sativa (rice), exhibits antimicrobial activity against rice pathogens. Intriguingly, OsAFP1 was also shown to demonstrate potent antifungal activity against the human pathogenic fungus Candida albicans by inducing apoptosis in target cells, suggesting that OsAFP1 represents a potential new antibiotic candidate; however, further analyses, particularly at the structural level, are required to elucidate the mechanistic underpinnings of OsAFP1 antifungal activity. Here, we determined the three-dimensional structure of OsAFP1 using X-ray crystallography. OsAFP1 features the cysteine-stabilized αß structure highly conserved in plant defensins and presents a dimeric structure that appears necessary for antifungal activity. Superimposition of the OsAFP1 structure with that of Nicotiana alata NaD1 complexed with phosphatidic acid indicated that the target molecule is likely trapped between the S2-S3 loops of each OsAFP1 dimer. In lipid-binding analyses performed using nitrocellulose membranes immobilized with various membrane lipid components, OsAFP1 was found to bind to phosphatidylinositols (PIPs) harboring phosphate groups, particularly PI(3)P. These results indicate that OsAFP1 exerts antifungal activity by binding to PI(3)P contained in the C. albicans cell membrane, thereby applying cellular stress and inducing apoptosis. Furthermore, the OsAFP1 structure and site-specific-mutation analyses revealed that Arg1, His2, Leu4, Arg9, and Phe10 play critical roles in OsAFP1 dimer formation. Thus, our study provides novel insights into the antifungal mechanism of OsAFP1.


Assuntos
Defensinas/química , Defensinas/metabolismo , Oryza/metabolismo , Fosfatidilinositóis/metabolismo , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Antifúngicos/química , Antifúngicos/metabolismo , Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Candida albicans/metabolismo , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Cristalização , Defensinas/genética , Defensinas/farmacologia , Oryza/química , Oryza/genética , Fosfatidilinositóis/química , Proteínas de Plantas/genética , Proteínas de Plantas/farmacologia
8.
J Appl Microbiol ; 129(3): 486-495, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32115828

RESUMO

Clonostachys rosea is a promising saprophytic filamentous fungus that belongs to phylum Ascomycota. Clonostachys rosea is widespread around the world and exists in many kinds of habitats, with the highest frequency in soil. As an excellent mycoparasite, C. rosea exhibits strong biological control ability against numerous fungal plant pathogens, nematodes and insects. These behaviours are based on the activation of multiple mechanisms such as secreted cell-wall-degrading enzymes, production of antifungal secondary metabolites and induction of plant defence systems. Besides having significant biocontrol activity, C. rosea also functions in the biodegradation of plastic waste, biotransformation of bioactive compounds, as a bioenergy sources and in fermentation. This mini review summarizes information about the biology and various applications of C. rosea and expands on its possible uses.


Assuntos
Hypocreales/fisiologia , Controle Biológico de Vetores , Animais , Antibiose , Antifúngicos/metabolismo , Antinematódeos/metabolismo , Biodegradação Ambiental , Fermentação , Hypocreales/metabolismo , Doenças das Plantas/microbiologia , Doenças das Plantas/parasitologia , Doenças das Plantas/prevenção & controle , Plásticos/metabolismo
9.
Microb Cell Fact ; 19(1): 71, 2020 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-32192516

RESUMO

Notonesomycin A is a 32-membered bioactive glycosylated macrolactone known to be produced by Streptomyces aminophilus subsp. notonesogenes 647-AV1 and S. aminophilus DSM 40186. In a high throughput antifungal screening campaign, we identified an alternative notonesomycin A producing strain, Streptomyces sp. A793, and its biosynthetic gene cluster. From this strain, we further characterized a new more potent antifungal non-sulfated analogue, named notonesomycin B. Through CRISPR-Cas9 engineering of the biosynthetic gene cluster, we were able to increase the production yield of notonesomycin B by up to 18-fold as well as generate a strain that exclusively produces this analogue.


Assuntos
Antifúngicos/isolamento & purificação , Macrolídeos/isolamento & purificação , Streptomyces/genética , Antifúngicos/metabolismo , Clonagem Molecular , Macrolídeos/metabolismo , Família Multigênica , Streptomyces/metabolismo
10.
Int J Food Microbiol ; 322: 108574, 2020 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-32151821

RESUMO

Fungi are commonly identified as the cause for dairy food spoilage. This can lead to substantial economic losses for the dairy industry as well as consumer dissatisfaction. In this context, biopreservation of fermented dairy products using lactic acid bacteria, propionibacteria and fungi capable of producing a large range of antifungal metabolites is of major interest. In a previous study, extensive screening was performed in vitro and in situ to select 3 dairy fermentates (derived from Acidipropionibacterium jensenii CIRM-BIA1774, Lactobacillus rhamnosus CIRM-BIA1952 and Mucor lanceolatus UBOCC-A-109193, respectively) with antifungal activity. The aim of the present study was to determine the main compounds responsible for this antifungal activity. Fifty-six known antifungal compounds as well as volatiles were targeted using different analytical methods (conventional LC and GC, GC-MS, LC-QToF). The most abundant antifungal compounds in P. jensenii-, L. rhamnosus- and M. lanceolatus-derived fermentates corresponded to propionic and acetic acids, lactic and acetic acids, and butyric acid, respectively. Many other antifungal compounds (organic acids, free fatty acids, volatile compounds) were identified but at lower levels. In addition, an untargeted approach using nano LC-MS/MS identified a 9-amino acid peptide derived from αs2-casein in the L. rhamnosus-derived fermentate. This peptide inhibited M. racemosus and R. mucilaginosa in vitro. This study provides new insights on the molecules involved in antifungal activities of food-grade microorganism fermentates which could be used as antifungal ingredients in the dairy industry.


Assuntos
Antifúngicos/análise , Produtos Fermentados do Leite/análise , Conservantes de Alimentos/análise , Antifúngicos/química , Antifúngicos/metabolismo , Antifúngicos/farmacologia , Reatores Biológicos , Produtos Fermentados do Leite/microbiologia , Fermentação , Microbiologia de Alimentos , Conservantes de Alimentos/química , Conservantes de Alimentos/metabolismo , Conservantes de Alimentos/farmacologia , Lactobacillus rhamnosus/isolamento & purificação , Lactobacillus rhamnosus/metabolismo , Mucor/isolamento & purificação , Mucor/metabolismo , Propionibacterium/isolamento & purificação , Propionibacterium/metabolismo , Rhodotorula/efeitos dos fármacos
11.
Microb Cell Fact ; 19(1): 18, 2020 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-32005241

RESUMO

BACKGROUND: Amphotericin B (AmB) is widely used against fungal infection and produced mainly by Streptomyces nodosus. Various intracellular metabolites of S. nodosus were identified during AmB fermentation, and the key compounds that related to the cell growth and biosynthesis of AmB were analyzed by principal component analysis (PCA) and partial least squares (PLS). RESULTS: Rational design that based on the results of metabolomics was employed to improve the AmB productivity of Streptomyces nodosus, including the overexpression of genes involved in oxygen-taking, precursor-acquiring and product-exporting. The AmB yield of modified strain S. nodosus VMR4A was 6.58 g/L, which was increased significantly in comparison with that of strain S. nodosus ZJB2016050 (5.16 g/L). This was the highest yield of AmB reported so far, and meanwhile, the amount of by-product amphotericin A (AmA) was decreased by 45%. Moreover, the fermentation time of strain S. nodosus VMR4A was shortened by 24 h compared with that of strain. The results indicated that strain S. nodosus VMR4A was an excellent candidate for the industrial production of AmB because of its high production yield, low by-product content and the fast cell growth. CONCLUSIONS: This study would lay the foundation for improving the AmB productivity through metabolomics analysis and overexpression of key enzymes.


Assuntos
Anfotericina B/biossíntese , Biotecnologia/métodos , Fermentação , Metabolômica/métodos , Streptomyces , Antifúngicos/metabolismo , Streptomyces/crescimento & desenvolvimento , Streptomyces/metabolismo
12.
Biochemistry (Mosc) ; 85(Suppl 1): S154-S176, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32087058

RESUMO

In this review, we present the data on the natural occurrence of chitin and its partially or fully deacetylated derivative chitosan, as well as their properties, methods of modification, and potential applications of derivatives with bactericidal, fungicidal, and antioxidant activities. The structure and physicochemical characteristics of the polymers, their functions, and features of chitin microbial synthesis and degradation, including the processes occurring in nature, are described. New data on the hydrolytic microorganisms capable of chitin degradation under extreme conditions are presented. Special attention is focused on the effect of physicochemical characteristics of chitosan, including molecular weight, degree of deacetylation, polydispersity index, and number of amino group derivatives (quaternized, succinyl, etc.) on the antimicrobial and antioxidant properties of modified polymers that can be of particular interest for biotechnology, medicine, and agriculture. Analysis of the available literature data confirms the importance of fundamental research to broaden our knowledge on the occurrence of chitin and chitosan in nature, their role in global biosphere cycles, and prospects of applied research aimed at using chitin, chitosan, and their derivatives in various aspects of human activity.


Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Antioxidantes/farmacologia , Quitosana/análogos & derivados , Quitosana/farmacologia , Fungicidas Industriais/farmacologia , Antibacterianos/química , Antibacterianos/metabolismo , Antifúngicos/química , Antifúngicos/metabolismo , Antioxidantes/química , Antioxidantes/metabolismo , Bactérias/metabolismo , Biotecnologia , Quitosana/química , Quitosana/metabolismo , Proteção de Cultivos , Descoberta de Drogas , Fungicidas Industriais/química , Fungicidas Industriais/economia , Fungicidas Industriais/metabolismo , Humanos , Hidrólise , Peso Molecular , Polímeros
13.
Infect Immun ; 88(4)2020 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-31932331

RESUMO

Candida albicans is a pervasive commensal fungus that is the most common pathogen responsible for invasive fungal infection (IFI). With incidence of IFI on the rise due to increasing susceptible populations, it is imperative that we investigate how Candida albicans interacts with blood components. When stimulating either human or mouse whole blood with thrombin, we saw a significant decrease in C. albicans survival. We then repeated Candida killing assays with thrombin-stimulated or unstimulated washed platelets and saw a similar decrease in CFU. To investigate whether killing was mediated through surface components or releasable products, platelets were pretreated with an inhibitor of actin polymerization (cytochalasin D [CytoD]). CytoD was able to abrogate C. albicans killing. Moreover, dilution of releasates from thrombin-stimulated platelets showed that the toxicity of the releasates on C. albicans is concentration dependent. We then investigated C. albicans actions on platelet activation, granule release, and aggregation. While C. albicans does not appear to affect alpha or dense granule release, C. albicans exerts a significant attenuation of platelet aggregation to multiple agonists. These results illustrate for the first time that platelets can directly kill C. albicans through release of their granular contents. Additionally, C. albicans can also exert inhibitory effects on platelet aggregation.


Assuntos
Antifúngicos/metabolismo , Plaquetas/metabolismo , Plaquetas/microbiologia , Candida albicans/imunologia , Fatores Imunológicos/metabolismo , Animais , Candida albicans/fisiologia , Contagem de Colônia Microbiana , Humanos , Camundongos , Viabilidade Microbiana/efeitos dos fármacos
14.
Comput Biol Chem ; 84: 107189, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31891900

RESUMO

A series of indole-derived methoxylated chalcones were described as anti-dermatophyte agents. The in vitro antifungal susceptibility testing against different dermatophytes revealed that most of compounds had potent activity against the dermatophyte strains. In particular, the 4-ethoxy derivative 4d with MIC values of 0.25-2 µg/ml was the most potent compound against Trichophyton interdigitale, Trichophyton veruccosum and Microsporum fulvum. Moreover, the 4-butoxy analog 4i displaying MIC values in the range of 1-16 µg/ml had the highest inhibitory activity against Trichophyton mentagrophytes, Microsporum canis, and Arthroderma benhamiae. To predict whether the synthesized compounds interact with tubulin binding site of dermatophytes, the 3D-structure of target protein was modeled by homology modeling and then used for molecular docking and molecular dynamics (MD) simulation studies. Docking simulation revealed that the promising compound 4d can properly bind with tubulin. The molecular dynamics analysis showed that interactions of compound 4d with the active site of target protein have binding stability throughout MD simulation. The results of this study could utilize in the design of more effective antifungal drugs with tubulin inhibition mechanism against keratinophilic fungi.


Assuntos
Antifúngicos/farmacologia , Chalconas/farmacologia , Indóis/farmacologia , Sequência de Aminoácidos , Antifúngicos/química , Antifúngicos/metabolismo , Arthrodermataceae/efeitos dos fármacos , Sítios de Ligação , Chalconas/química , Chalconas/metabolismo , Humanos , Indóis/química , Indóis/metabolismo , Testes de Sensibilidade Microbiana , Fungos Mitospóricos/efeitos dos fármacos , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Estrutura Molecular , Ligação Proteica , Alinhamento de Sequência , Relação Estrutura-Atividade , Tubulina (Proteína)/química , Tubulina (Proteína)/metabolismo
15.
Microbiol Res ; 232: 126389, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31821969

RESUMO

This study describes the biocontrol potential of rhizobacteria against a range of fungal phytopathogens. Out of 227 bacteria isolated from the rhizosphere of maize, rice, wheat, potato, sunflower and soybean crops cultivated in different agro-ecological regions of Pakistan, 48 exhibited >60 % antifungal activity against Fusarium oxysporum, Fusarium moniliforme, Rhizoctonia solani, Colletotrichum gloeosporioides, Colletotrichum falcatum, Aspergillus niger, and Aspergillus flavus. The rhizobacteria inhibiting >65 % pathogen growth were selected for detailed molecular and in planta studies most of which were identified as Pseudomonas and Bacillus species based on 16S rRNA gene sequence analysis. Antifungal metabolites produced by these rhizobacteria analyzed through LCMS were identified as antibiotics (iturin, surfactins, fengycin, DAPG, Phenazine, etc.), cell wall degrading enzymes (protease, chitinase, and cellulase), plant growth promotion enzymes and hormones (indole-3-acetic acid, ACC-deaminase, phosphates, nitrogen fixation), N-acyl-homoserine lactones and siderophores. The growth room experiment validated the potential of these bacteria as biofertilizer and biopesticide agents. Of all, P. aeruginosa strain FB2 and B. subtilis strain RMB5 showed significantly higher potential as antagonistic plant-beneficial bacteria effective against a range of fungal phytopathogens. Both these bacteria can be used to develop a dual-purpose bacterial inoculum as biopesticide and biofertilizer. Rest of the antagonistic PGPR may be exploited for disease control in less-infested soils.


Assuntos
Antifúngicos/metabolismo , Antifúngicos/farmacologia , Bactérias/metabolismo , Fungos/efeitos dos fármacos , Rizosfera , Antibacterianos/metabolismo , Aspergillus flavus/efeitos dos fármacos , Aspergillus niger/efeitos dos fármacos , Bacillus/metabolismo , Bactérias/genética , Bactérias/isolamento & purificação , Biofilmes/crescimento & desenvolvimento , Agentes de Controle Biológico/metabolismo , Agentes de Controle Biológico/farmacologia , Colletotrichum/efeitos dos fármacos , Fusarium/efeitos dos fármacos , Cianeto de Hidrogênio/metabolismo , Cianeto de Hidrogênio/farmacologia , Ácidos Indolacéticos/metabolismo , Ácidos Indolacéticos/farmacologia , Fixação de Nitrogênio , Paquistão , Desenvolvimento Vegetal/efeitos dos fármacos , Desenvolvimento Vegetal/imunologia , Doenças das Plantas/microbiologia , Raízes de Plantas/microbiologia , Pseudomonas/metabolismo , Pseudomonas aeruginosa , Percepção de Quorum , RNA Ribossômico 16S/genética , Rhizoctonia/efeitos dos fármacos , Sideróforos/metabolismo , Sideróforos/farmacologia , Zea mays/microbiologia
16.
J Appl Microbiol ; 128(3): 803-813, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31705716

RESUMO

AIMS: This study aimed to obtain an antagonistic endophyte against Sclerotium rolfsii from peanut seeds, evaluate the biocontrol efficacy towards peanut stem rot and explore its antifungal mechanism against S. rolfsii. METHODS AND RESULTS: Thirty-seven endophytic bacteria were isolated from peanut seeds, six of which exhibited stronger antagonistic activities against S. rolfsii (inhibition rate, IR of hyphae growth ≥70%). Strain LHSB1, the strongest antagonistic strain, was identified as Bacillus velezensis. LHSB1 showed 93·8% of radial growth inhibition of S. rolfsii hyphae and exhibited obvious antagonistic activity against another six pathogenic fungi of peanut. Pot experiments showed two different LHSB1 treatments both significantly reduced the disease incidence and severity of stem rot (P < 0·05) compared to the controls, and the biocontrol efficacy reached 62·6-70·8%, significantly higher than that of Carbendazim control (P < 0·05). Further analyses revealed LHSB1 culture filtrate significantly inhibited sclerotia formation and germination, caused the abnormalities and membrane integrity damage of S. rolfsii hyphae, which might be the possible mode of action of LHSB1 against S. rolfsii. Three antifungal lipopeptides bacillomycin A, surfactin A and fengycin A, were detected in LHSB1 culture extracts by UPLC-ESI-MS, which could be responsible for the biocontrol activity of LHSB1 against S. rolfsii. CONCLUSION: Our results suggested that the seed-borne endophytic B. velezensis LHSB1 would be a tremendous potential agent for the biocontrol of peanut stem rot caused by S. rolfsii. SIGNIFICANCE AND IMPACT OF THE STUDY: This comprehensive study provides a candidate endophytic biocontrol strain and reveals its antifungal mechanism against S. rolfsi. To the best of our knowledge, this is the first time that seed-borne endophytic B. velezensis was used as the biocontrol agent to control peanut stem rot.


Assuntos
Arachis/microbiologia , Bacillus/fisiologia , Basidiomycota/crescimento & desenvolvimento , Agentes de Controle Biológico , Doenças das Plantas/prevenção & controle , Antifúngicos/metabolismo , Antifúngicos/farmacologia , Bacillus/metabolismo , Basidiomycota/efeitos dos fármacos , Endófitos/fisiologia , Germinação , Hifas/crescimento & desenvolvimento , Doenças das Plantas/microbiologia , Sementes/microbiologia
17.
J Appl Microbiol ; 128(3): 814-827, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31710757

RESUMO

AIMS: Plant tissues are the reservoirs of beneficial and harmful microbes that regulates plant growth. In the present study, we investigated the diversity, function and colonization of sugarcane roots associated with Bacillus spp. METHODS AND RESULTS: A total of 20 Bacillus strains were isolated and identified by 16S rRNA gene sequencing, and their genetic diversity was examined by BOX, ERIC, REP, (GTG)5 PCR techniques. Among all Bacillus isolates, 65% showed indole acetic acid-like compounds production, 50% solubilized phosphorus and 25% of the isolates were able to secrete siderophore. Moreover, all 20 Bacillus isolates showed antifungal activity against eight fungal pathogens and 11 of them (55%) antagonized tomato grey mold. Based on the plant growth-promoting traits and antifungal potential, isolate Y8 was selected for root and plant tissue colonization assays and a greenhouse-level sugarcane growth promotion study. Fluorescence microscopy results confirmed that isolate Y8 has a strong ability to colonize in the sugarcane root and leaves, and the root surface association of Y8 was confirmed by scanning electron microscopy. Furthermore, greenhouse experimental results demonstrated that Y8 has a significant effect on enhancing sugarcane biomass and root length. CONCLUSIONS: Endophytic Bacillus strains have growth-promoting properties and anti-fungal ability that can enhance plant fitness in an eco-friendly manner. SIGNIFICANCE AND IMPACT OF THE STUDY: Endophytic Bacillus strains would be a potential alternative to chemical fertilizer as well as a biocontrol agent in the future.


Assuntos
Bacillus/isolamento & purificação , Bacillus/fisiologia , Saccharum/crescimento & desenvolvimento , Saccharum/microbiologia , Antifúngicos/metabolismo , Bacillus/genética , Bacillus/metabolismo , Endófitos/genética , Endófitos/isolamento & purificação , Endófitos/metabolismo , Endófitos/fisiologia , Fungos/classificação , Fungos/genética , Variação Genética , Ácidos Indolacéticos/metabolismo , Fósforo/metabolismo , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Sideróforos/metabolismo
18.
Xenobiotica ; 50(5): 614-619, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31573401

RESUMO

1. Voriconazole is known to display highly variable pharmacokinetics affecting treatment efficacy and safety. This study aimed to identify the factors causing the variation of voriconazole concentration in patients with allogeneic hematopoietic stem cell transplantation.2. The data of patients was collected, including clinical characteristics and voriconazole concentrations. A total of 5 single nucleotide polymorphisms of 3 candidate genes (CYP2C19, ABCC2, ABCG2) related to voriconazole metabolism were genotyped by MassArray method. The correlation between polymorphisms and voriconazole concentration was analyzed.3. A total of 244 voriconazole concentrations of 43 patients were included in this study. The voriconazole concentration was significantly correlated with patients' total bile acid (p = 0.001) and cyclosporin A (p < 0.001). The median concentration of the CYP2C19 normal metabolizers was remarkably lower than poor metabolizers (0.86 vs 2.27 µg/mL). The median concentration of ABCC2 rs2273697 GG genotype carriers was significantly higher than that of GA genotype carriers (p = 0.026).4. The variability of voriconazole concentration is partially explained by total bile acid, metabolic types of CYP2C19. The voriconazole concentration of CYP2C19 normal metabolizers is likely to be lower than 1.0 µg/mL and thus at risk of infection due to inadequate treatment.


Assuntos
Antifúngicos/farmacologia , Ciclosporina/farmacologia , Citocromo P-450 CYP2C19/genética , Voriconazol/metabolismo , Adulto , Antifúngicos/metabolismo , Ciclosporina/metabolismo , Transplante de Células-Tronco Hematopoéticas , Humanos , Proteínas Associadas à Resistência a Múltiplos Medicamentos , Variantes Farmacogenômicos , Polimorfismo de Nucleotídeo Único
19.
Insect Biochem Mol Biol ; 116: 103258, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31678582

RESUMO

The protease inhibitors found in silkworm cocoons can be divided into several families, a majority of which contain serpin, TIL, or Kunitz domains. Previously, it has been reported that TIL-type protease inhibitors have antimicrobial activity. To date, however, it has not been determined whether the Kunitz-type protease inhibitor BmSPI51, the most abundant of cocoon protease inhibitors, plays an antimicrobial role. Thus, in this study, we sought to determine the biological role of BmSPI51 in silkworm cocoons. Our results obtained from real-time quantitative reverse transcription PCR and immunofluorescence analyses indicate that BmSPI51 is expressed exclusively in the silk glands during the larval fifth instar stage and is subsequently secreted into cocoon silk. Moreover, at a molar ratio of 1:1, BmSPI51 produced via prokaryotic expression exhibited inhibitory activity against trypsin and also proved to be highly stable over wide ranges of temperature and pH values. The expression of BmSPI51 was also found to be significantly upregulated in the larval fat body after infection with three species of fungi, namely, Candida albicans, Beauveria bassiana, and Saccharomyces cerevisiae. In vitro inhibition tests revealed that BmSPI51 significantly inhibited the sporular growth of all three of these fungal species. Further, results obtained from a binding assay showed that BmSPI51 binds to ß-d-glucan and mannan on the surface of fungal cells. In this study, we, thus, revealed the antimicrobial activity of BmSPI51 and its underlying mechanism in silkworm, thereby contributing to our present understanding of defense mechanisms in silkworm cocoons.


Assuntos
Bombyx/metabolismo , Bombyx/microbiologia , Proteínas de Insetos/genética , Inibidores de Serino Proteinase/genética , Animais , Antifúngicos/metabolismo , Beauveria/fisiologia , Bombyx/crescimento & desenvolvimento , Candida albicans/fisiologia , Corpo Adiposo/química , Proteínas de Insetos/metabolismo , Larva/crescimento & desenvolvimento , Larva/metabolismo , Larva/microbiologia , Saccharomyces cerevisiae/fisiologia , Inibidores de Serino Proteinase/metabolismo
20.
Chem Biodivers ; 17(2): e1900624, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31863703

RESUMO

In search for new fungicidal and free radical scavenging agents, we synthesized a focused library of 2-chloroquinoline based monocarbonyl analogs of curcumin (MACs). The synthesized MACs were evaluated for in vitro antifungal and antioxidant activity. The antifungal activity was evaluated against five different fungal strains such as Candida albicans, Fusarium oxysporum, Aspergillus flavus, Aspergillus niger, and Cryptococcus neoformans, respectively. Most of the synthesized MACs displayed promising antifungal activity compared to the standard drug Miconazole. Furthermore, molecular docking study on a crucial fungal enzyme sterol 14α-demethylase (CYP51) could provide insight into the plausible mechanism of antifungal activity. MACs were also screened for in vitro radical scavenging activity using butylated hydroxytoluene (BHT) as a standard. Almost all MACs exhibited better antioxidant activity compared to BHT.


Assuntos
Antifúngicos/síntese química , Antioxidantes/química , Curcumina/análogos & derivados , Proteínas Fúngicas/metabolismo , Simulação de Acoplamento Molecular , Quinolinas/química , Antifúngicos/metabolismo , Antifúngicos/farmacologia , Aspergillus/efeitos dos fármacos , Sítios de Ligação , Candida albicans/efeitos dos fármacos , Domínio Catalítico , Cryptococcus neoformans/efeitos dos fármacos , Curcumina/metabolismo , Curcumina/farmacologia , Proteínas Fúngicas/química , Testes de Sensibilidade Microbiana , Esterol 14-Desmetilase/química , Esterol 14-Desmetilase/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA