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1.
J Agric Food Chem ; 67(41): 11403-11407, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31509401

RESUMO

Three new phenazine metabolites, strepphenazine A-C (1-3), along with a known compound baraphenazine E 4 were isolated from the culture broth of a Streptomyces strain YIM PH20095. The structures were elucidated based on the spectral data. Compounds 1-4 showed different antifungal activity against Fusarium oxysporum, Plectosphaerella cucumerina, Alternaria panax, and Phoma herbarum, which caused root-rot disease of Panax notoginseng with minimal inhibitory concentrations (MICs) of 16-64 µg/mL; compared with compound 4, compounds 1-3 showed better antifungal activity against some of these pathogenic fungi with MICs of 16-32 µg/mL, while compound 4 showed antifungal activity against F. oxysporum, P. cucumerina, and A. panax with the same MICs of 64 µg/mL. Thus, strain YIM PH20095 provides new sources for the development of biological control agents to prevent the infection of pathogenic fungi of P. notoginseng.


Assuntos
Antifúngicos/química , Antifúngicos/farmacologia , Panax notoginseng/microbiologia , Fenazinas/química , Fenazinas/farmacologia , Streptomyces/química , Alternaria/efeitos dos fármacos , Alternaria/crescimento & desenvolvimento , Antifúngicos/isolamento & purificação , Antifúngicos/metabolismo , Fusarium/efeitos dos fármacos , Fusarium/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Estrutura Molecular , Fenazinas/isolamento & purificação , Fenazinas/metabolismo , Doenças das Plantas/microbiologia
2.
World J Microbiol Biotechnol ; 35(8): 128, 2019 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-31375920

RESUMO

Large patch disease, caused by Rhizoctonia solani AG2-2, is the most devastating disease in Zoysiagrass (Zoysia japonica). Current large patch disease control strategies rely primarily upon the use of chemical pesticides. Streptomyces sp. S8 is known to possess exceptional antagonistic properties that could potentially suppress the large patch pathogen found at turfgrass plantations. This study aims to demonstrate the feasibility of using the strain as a biological control mechanism. Sequencing of the S8 strain genome revealed a valinomycin biosynthesis gene cluster. This cluster is composed of the vlm1 and vlm2 genes, which are known to produce antifungal compounds. In order to verify this finding for the large patch pathogen, a valinomycin biosynthesis knockout mutant was created via the CRISPR/Cas9 system. The mutant lost antifungal activity against the large patch pathogen. Consequently, it is anticipated that eco-friendly microbial preparations derived from the S8 strain can be utilized to biologically control large patch disease.


Assuntos
Antifúngicos/metabolismo , Antifúngicos/farmacologia , Rhizoctonia/efeitos dos fármacos , Streptomyces/metabolismo , Valinomicina/metabolismo , Valinomicina/farmacologia , Vias Biossintéticas/genética , Técnicas de Inativação de Genes , Genoma Bacteriano , Família Multigênica , Controle Biológico de Vetores/métodos , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Poaceae/microbiologia , Rhizoctonia/crescimento & desenvolvimento , Análise de Sequência de DNA , Streptomyces/genética
3.
Pestic Biochem Physiol ; 159: 41-50, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31400783

RESUMO

Emerging fungal phytodiseases are a food security threat and novel fungicides are in an urgent need. Herein, a series of isobutyrophenone derivatives were designed and synthesized. The derivatives exhibited excellent fungicidal activities against seven fungi. The structure-activity relationship (SAR) study indicated that the introduction of a bromo group at the position 3 or 5 of the phenyl ring, as well as esterification of the 4-hydroxy with a chloroacetyl group, could substantially increase the antifungal activity and spectrum of the compounds. Among all 23 compounds, 2-bromo-3-hydroxy-4-isobutyryl-6-methylphenyl 2-chloroacetate (12b) showed the highest fungicidal activity against all seven tested fungal pathogens with EC50 values ranging from 1.22 to 39.94 µg/mL and exhibited the most potent inhibition against class II fructose-1,6-bisphosphate aldolase with an IC50 of 3.63 µM. The lead compounds were proven to be safe to NIH3T3/293 T cells and silkworm larvae, and relatively stable under different harsh conditions. Detached fruit tests showed the practical potential of lead compounds for fruit (or plant) protection. Taken together, our results indicated that the isobutyrophenone derivatives could be further optimized and developed as advanced leads for new fungicides.


Assuntos
Antifúngicos/química , Antifúngicos/metabolismo , Frutose-Bifosfato Aldolase/metabolismo , Animais , Bombyx/metabolismo , Linhagem Celular , Frutose-Bifosfato Aldolase/genética , Humanos , Larva/metabolismo , Camundongos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Células NIH 3T3 , Relação Estrutura-Atividade
4.
Eur J Med Chem ; 177: 374-385, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31158751

RESUMO

To discover broad spectrum antifungal agents, two strategies were applied, and a novel class of l-amino alcohol derivatives were designed and synthesized. 3-F substituted compounds 14i, 14n, 14s and 14v exhibited excellent antifungal activities with broad antifungal spectra against C. albicans and C. tropicalis, with MIC values in the range of 0.03-0.06 µg/mL, and against A. fumigatus and C. neoformans, with MIC values in the range of 1-2 µg/mL. Notably, Compounds 14i, 14n, 14s and 14v also displayed moderate activities against fluconazole-resistance strains 17# and CaR that were isolated from AIDS patients. Moreover, only compounds in the S-configuration showed antifungal activity. Preliminary mechanistic studies showed that the potent antifungal activity of compound 14v stemmed from inhibition of C. albicans CYP51. Compounds 14n and 14v were almost nontoxic to mammalian A549 cells, and their stability in human plasma was excellent.


Assuntos
Amino Álcoois/farmacologia , Antifúngicos/farmacologia , Células A549 , Amino Álcoois/síntese química , Amino Álcoois/metabolismo , Amino Álcoois/toxicidade , Antifúngicos/síntese química , Antifúngicos/metabolismo , Antifúngicos/toxicidade , Aspergillus fumigatus/efeitos dos fármacos , Aspergillus fumigatus/enzimologia , Candida albicans/efeitos dos fármacos , Candida tropicalis/efeitos dos fármacos , Domínio Catalítico , Cryptococcus neoformans/efeitos dos fármacos , Desenho de Drogas , Estabilidade de Medicamentos , Ergosterol/metabolismo , Humanos , Testes de Sensibilidade Microbiana , Ligação Proteica , Estereoisomerismo , Esterol 14-Desmetilase/química , Esterol 14-Desmetilase/metabolismo , Relação Estrutura-Atividade
5.
World J Microbiol Biotechnol ; 35(6): 92, 2019 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-31187317

RESUMO

Polyketides and peptides obtained from actinobacteria are important therapeutic compounds which include front line antibiotics and anticancer drugs. Many screening programs are directed towards isolation of bioactive compounds from these organisms but the chances of finding novel antimicrobial leads among common actinobacteria are fast dwindling. As a result, the focus has shifted to the members of less exploited genera of rare actinobacteria. Three isolates, MMS8, MMS16 and KCR3 found to be potent polyketide and peptide producers were identified by 16S rRNA gene sequencing and their sequences deposited in the GenBank under the accession numbers MG407702, MG372012 and MG430204 respectively. MMS8 identified as Micromonospora auratinigra, yielded one potent compound determined to be chloroanthraquinone with an minimum inhibitory concentration (MIC) of 8 µg/ml against Bacillus subtilis and an IC50 value of 10 µg/ml and 4 µg/ml against HeLa and IMR cell lines respectively. This is the first report of the production of chloroanthraquinone by M. auratinigra. MMS16, identified as a member of the family Micromonosporaceae, yielded a potent compound MMS16B analyzed to be a novel bafilomycin analogue. The MIC of the compound was found to be 7 µg/ml against B.subtilis and IC50 value against HeLa and IMR was observed to be 9 µg/ml and 14 µg/ml respectively. MMS16B was also found to exhibit anti-quorum sensing (AQS) activity at sublethal concentrations. KCR3 identified as Kocuria kristinae yielded a novel antimicrobial peptide with antibacterial, antifungal and AQS activity. To the best of our knowledge, no antimicrobial activity has ever been reported from K. kristinae.


Assuntos
Actinobacteria/metabolismo , Peptídeos/metabolismo , Policetídeos/metabolismo , Actinobacteria/genética , Actinobacteria/isolamento & purificação , Animais , Antibacterianos/metabolismo , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Antifúngicos/metabolismo , Antifúngicos/farmacologia , Antineoplásicos/metabolismo , Bacillus subtilis/efeitos dos fármacos , Linhagem Celular , Testes de Sensibilidade Microbiana , Micromonospora/genética , Micromonospora/isolamento & purificação , Micromonospora/metabolismo , Peptídeos/isolamento & purificação , Peptídeos/farmacologia , Policetídeos/isolamento & purificação , Policetídeos/farmacologia , RNA Ribossômico 16S/genética
6.
J Agric Food Chem ; 67(20): 5820-5826, 2019 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-31060357

RESUMO

This work aims to uncover how glucose affected the production of phenyllactic acid (PLA) and p-hydroxyphenyllactic acid ( p-OH-PLA). The highest yields of PLA (68.53 mg/L) and p-OH-PLA (50.39 mg/L) were observed after Lactobacillus plantarum strain YM-4-3 fermentation in media containing 30 and 10 g/L glucose, respectively. Additionally, the antimicrobial activity of YM-4-3 against food-borne pathogens and the NADH/NAD+ ratio were positively correlated with the production of PLA and p-OH-PLA, respectively. In addition, a 2-oxoglutarate/malate translocator coding gene ( Omt1) was selected based on the qPCR results, and its knockout mutant, compared with the wild-type strain YM-4-3, showed that the PLA and p-OH-PLA production was decreased by 1.37-6.99 and 1.53-1.59 times, respectively. This result indicated that OMT1 was involved in the biosynthesis of PLA and p-OH-PLA. To conclude, this study suggests that glucose, NADH/NAD+ ratio and/or the Omt1 gene, PLA, and p-OH-PLA production, and antimicrobial activity contribute to a cause-and-effect relationship.


Assuntos
Antibacterianos/metabolismo , Antifúngicos/metabolismo , Proteínas de Bactérias/metabolismo , Glucose/metabolismo , Ácidos Cetoglutáricos/metabolismo , Lactatos/metabolismo , Lactobacillus plantarum/metabolismo , Malatos/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Fenilalanina/análogos & derivados , Antibacterianos/farmacologia , Antifúngicos/farmacologia , Bactérias/efeitos dos fármacos , Proteínas de Bactérias/genética , Fermentação , Microbiologia de Alimentos , Fungos/efeitos dos fármacos , Lactatos/farmacologia , Lactobacillus plantarum/genética , Proteínas de Membrana Transportadoras/genética , Fenilalanina/biossíntese
7.
IET Nanobiotechnol ; 13(2): 114-119, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31051440

RESUMO

Fluconazole (FLZ) application as a highly successful commercial antifungal azole agent to treat the fungal infections is limited due to emergence of FLZ-resistant candida. In this study, the potential of green synthesised silver nanoparticles (NPs) as an antifungal agent against Candida albicans fungal pathogen is investigated. The extract of ginger (Zingiber officinale) and thyme (Thymus vulgaris) plays as reducing agent, capping agent and antifungal agent. The UV-visible spectroscopy shows the peak of surface plasmon resonance of synthesised Ag NPs after a period of time. The synthesised Ag NPs are spherical, with average sizes of 12 and 18 nm based on ginger and thyme extract, respectively. Fourier transform infrared spectroscopy confirms the adsorption of the plant extract on the surface of the as-prepared Ag NPs. Based on the minimum inhibitory concentration (MIC) method against Candida albicans, the antifungal activity of as-prepared green synthesised Ag NPs shows higher inhibitory in comparison to FLZ. Finally, the Ag NPs synthesised via thyme extract shows no cytotoxicity with concentration below 3.5 ppm, which can be considered as an appropriate candidate instead of FLZ to treat the superficial fungal infections.


Assuntos
Antifúngicos/química , Gengibre/metabolismo , Nanopartículas Metálicas/química , Prata/química , Thymus (Planta)/metabolismo , Antifúngicos/metabolismo , Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Fluconazol/farmacologia , Química Verde , Humanos , Nanopartículas Metálicas/toxicidade , Extratos Vegetais/química , Prata/metabolismo , Prata/farmacologia
8.
IET Nanobiotechnol ; 13(2): 214-218, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31051453

RESUMO

Selenium (Se) is a rare and essential element for the human body and other living organisms because of its role in the structure of several proteins and having anti-oxidant properties to reduce oxidative stress at cells. Some microorganisms can absorb Se oxyanions and convert them into zero-valent Se (Se0) in the nanoscale dimensions, which can be used for producing Se nanoparticles (SeNPs). In the present study, SeNPs were intracellularly biosynthesised by yeast Nematospora coryli, which is an inexpensive method and does not involve using materials hazardous for human and environment. The produced NPs were refined by a two-phase system and then characterised and identified by ultraviolet-visible, X-ray diffraction, X-ray fluorescence, transmission electron microscope, and Fourier transform infrared spectroscopy analyses. The structural analysis of biosynthesised SeNPs showed spherical-shaped NPs with size ranging from 50 to 250 nm. Also, extracted NPs were applied to explore their anti-candida and anti-oxidant activities. The results of this investigation confirm the biological properties of Se.


Assuntos
Antifúngicos/metabolismo , Antioxidantes/metabolismo , Nanopartículas/química , Saccharomycetales/metabolismo , Selênio/metabolismo , Antifúngicos/química , Antifúngicos/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Compostos de Bifenilo/análise , Compostos de Bifenilo/metabolismo , Candida/efeitos dos fármacos , Tamanho da Partícula , Picratos/análise , Picratos/metabolismo , Saccharomycetales/química , Selênio/química
9.
IET Nanobiotechnol ; 13(2): 219-225, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31051454

RESUMO

Silver nanoparticles (Ag NPs) were synthesised using the crude ethyl acetate extracts of Ulva lactuca and evaluated their bioefficacy against two crop-damaging pathogens. The sets of lattice planes in the XRD spectrum for the Ag NPs were indexed to the 111, 200, 220 and 311 orientations and support the crystalline nature of the Ag NPs. The 3414 and 2968 cm-1 peaks were observed in crude algal thallus extract and they were characteristic of terpenoids. Further, a peak at 1389 cm-1 was observed as fatty acids. The marine macroalgae terpenoids and palmitic acid acted as reducing agent and stabiliser, respectively. The size (3 and 50 nm) and shape (spherical) of Ag NPs were recorded. The energy-dispersive X-ray spectroscopy analysis exemplified the presence of silver in its elemental nature. Moreover, U. lactuca Ag NPs were effective against two cotton phytopathogens namely Fusarium oxysporum f.sp. vasinfectum (FOV) and Xanthomonas campestris pv. malvacearum (XAM). The minimum inhibitory concentration was found to be 80.0 and 43.33 µg ml-1 against FOV and XAM, respectively. Results confirmed the anti-microbial activity of green nanoparticles against select pathogens and suggest their possible usage in developing antifungal agents for controlling destructive pathogens in a cotton agroecosystem.


Assuntos
Gossypium/microbiologia , Nanopartículas Metálicas/química , Doenças das Plantas/prevenção & controle , Alga Marinha/química , Prata/metabolismo , Antifúngicos/química , Antifúngicos/metabolismo , Antifúngicos/farmacologia , Fusarium/efeitos dos fármacos , Química Verde/métodos , Tamanho da Partícula , Doenças das Plantas/microbiologia , Extratos Vegetais/química , Extratos Vegetais/metabolismo , Prata/química , Espectroscopia de Infravermelho com Transformada de Fourier , Ulva/química
10.
BMC Genomics ; 20(1): 374, 2019 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-31088369

RESUMO

BACKGROUND: Phomafungin is a recently reported broad spectrum antifungal compound but its biosynthetic pathway is unknown. We combed publicly available Phoma genomes but failed to find any putative biosynthetic gene cluster that could account for its biosynthesis. RESULTS: Therefore, we sequenced the genome of one of our Phoma strains (F3723) previously identified as having antifungal activity in a high-throughput screen. We found a biosynthetic gene cluster that was predicted to synthesize a cyclic lipodepsipeptide that differs in the amino acid composition compared to Phomafungin. Antifungal activity guided isolation yielded a new compound, BII-Rafflesfungin, the structure of which was determined. CONCLUSIONS: We describe the NRPS-t1PKS cluster 'BIIRfg' compatible with the synthesis of the cyclic lipodepsipeptide BII-Rafflesfungin [HMHDA-L-Ala-L-Glu-L-Asn-L-Ser-L-Ser-D-Ser-D-allo-Thr-Gly]. We report new Stachelhaus codes for Ala, Glu, Asn, Ser, Thr, and Gly. We propose a mechanism for BII-Rafflesfungin biosynthesis, which involves the formation of the lipid part by BIIRfg_PKS followed by activation and transfer of the lipid chain by a predicted AMP-ligase on to the first PCP domain of the BIIRfg_NRPS gene.


Assuntos
Antifúngicos/química , Depsipeptídeos/química , Proteínas Fúngicas/genética , Saccharomycetales/genética , Sequência de Aminoácidos , Antifúngicos/metabolismo , Antifúngicos/farmacologia , Vias Biossintéticas , Depsipeptídeos/biossíntese , Depsipeptídeos/farmacologia , Genômica , Estrutura Molecular , Família Multigênica , Saccharomycetales/metabolismo , Sequenciamento Completo do Genoma
11.
J Microbiol ; 57(5): 396-404, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31062286

RESUMO

Aspergillus flavus is a saprophytic fungus that contaminates crops with carcinogenic aflatoxin. In the present work, the antifungal effects of volatile organic compounds (VOCs) from Streptomyces alboflavus TD-1 against A. flavus were investigated. VOCs from 8-day-old wheat bran culture of S. alboflavus TD-1 displayed strong inhibitory effects against mycelial growth, sporulation, and conidial germination of A. flavus. Severely misshapen conidia and hyphae of A. flavus were observed by scanning electron microscopy after exposure to VOCs for 6 and 12 h, respectively. Rhodamine 123 staining of mitochondria indicated that mitochondria may be a legitimate antifungal target of the VOCs from S. alboflavus TD-1. Furthermore, the VOCs effectively inhibited aflatoxin B1 production by downregulating genes involved in aflatoxin biosynthesis. Dimethyl trisulfide and benzenamine may play important roles in the suppression of A. flavus growth and production of aflatoxin. The results indicate that VOCs from S. alboflavus TD-1 have tremendous potential to be developed as a useful bio-pesticide for controlling A. flavus.


Assuntos
Aflatoxina B1/biossíntese , Antifúngicos/farmacologia , Aspergillus flavus/crescimento & desenvolvimento , Aspergillus flavus/metabolismo , Agentes de Controle Biológico/farmacologia , Streptomyces/metabolismo , Compostos Orgânicos Voláteis/farmacologia , Aflatoxina B1/genética , Antifúngicos/metabolismo , Agentes de Controle Biológico/metabolismo , Regulação para Baixo/efeitos dos fármacos , Regulação Fúngica da Expressão Gênica , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Sulfetos/farmacologia , Compostos Orgânicos Voláteis/metabolismo
12.
Appl Microbiol Biotechnol ; 103(11): 4623-4632, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30997552

RESUMO

Recent studies from our laboratory indicate that engineered silver nanoparticles can inhibit aflatoxin biosynthesis even at concentrations at which they do not demonstrate antifungal activities on the aflatoxin-producing fungus. Whether such inhibition can be modified by altering the nanoparticles' physical properties remains unclear. In this study, we demonstrate that three differently sized citrated-coated silver nanoparticles denoted here as NP1, NP2, and NP3 (where, sizes of NP1 < NP2 < NP3) inhibit aflatoxin biosynthesis at different effective doses in Aspergillus parasiticus, the plant pathogenic filamentous fungus. Recapping NP2 with polyvinylpyrrolidone coating (denoted here as NP2p) also altered its ability to inhibit aflatoxin production. Dose-response experiments with NP concentrations ranging from 10 to 100 ng mL-1 indicated a non-monotonic relationship between aflatoxin inhibition and NP concentration. The maximum inhibitory concentrations differed between the NP types. NP1 demonstrated maximum inhibition at 25 ng mL-1. Both NP2 and NP3 showed maximum inhibition at 50 ng mL-1, although NP2 resulted in a significantly higher inhibition than NP3. While both NP2 and NP2p demonstrated greater aflatoxin inhibition than NP1 and NP3, NP2p inhibited aflatoxin over a significantly wider concentration range as compared to NP2. Our results, therefore, suggest that nano-fungal interactions can be regulated by altering certain NP physical properties. This concept can be used to design NPs for mycotoxin prevention optimally.


Assuntos
Aflatoxinas/antagonistas & inibidores , Aflatoxinas/biossíntese , Antifúngicos/metabolismo , Aspergillus/efeitos dos fármacos , Metabolismo/efeitos dos fármacos , Nanopartículas Metálicas/química , Prata/metabolismo , Aspergillus/crescimento & desenvolvimento , Aspergillus/metabolismo , Nanopartículas Metálicas/ultraestrutura , Venenos
13.
Comput Biol Chem ; 80: 168-176, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30965174

RESUMO

The alarm is rang for friendly fire; Saccharomyces cerevisiae (S. cerevisiae) newfound as a fungal pathogen with an individual feature. S. cerevisiae has food safety and is not capable of producing infection but, when the host defenses are weakened, there is room for opportunistic S. cerevisiae strains to cause a health issues. Fungal diseases are challenging to treat because, unlike bacteria, the fungal are eukaryotes. Antibiotics only target prokaryotic cells, whereas compounds that kill fungi also harm the mammalian host. Small differences between mammalian and fungal cells regarding genes and proteins sequence and function make finding a drug target more challenging. Recently, Chitin synthase has been considered as a promising target for antifungal drug development as it is absent in mammals. In S. cerevisiae, CHS3, a class IV chitin synthase, produces 90% of the chitin and essential for cell growth. CHS3 from the trans-Golgi network to the plasma membrane requires assembly of the exomer complex (including proteins cargo such as CHS5, CHS6, Bach1, and Arf1). In this work, we performed SELEX (Systematic Evolution of Ligands by EXponential enrichment) as high throughput virtual screening of the RCSB data bank to find an aptamer as potential inhibit of the class IV chitin synthase of S. cerevisiae. Among all the candidates, G-rich VEGF (GVEGF) aptamer (PDB code: 2M53) containing locked sugar parts was observed as potential inhibitor of the assembly of CHS5-CHS6 exomer complex a subsequently block the chitin biosynthesis pathway as an effective anti-fungal. It was suggested from the simulation that an assembly of exomer core should begin CHS5-CHS6, not from CHS5-Bach1. It is notable that secondary structures of CHS6 and Bach1 was observed very similar, but they have only 25% identity at the amino acid sequence that exhibited different features in exomer assembly.


Assuntos
Proteínas Adaptadoras de Transporte Vesicular/metabolismo , Aptâmeros de Nucleotídeos/metabolismo , Quitina Sintase/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Membrana/metabolismo , Multimerização Proteica/efeitos dos fármacos , Proteínas de Saccharomyces cerevisiae/metabolismo , Fator A de Crescimento do Endotélio Vascular/química , Proteínas Adaptadoras de Transporte Vesicular/química , Sequência de Aminoácidos , Antifúngicos/metabolismo , Aptâmeros de Nucleotídeos/genética , Sítios de Ligação , Quitina Sintase/química , Quadruplex G , Peptídeos e Proteínas de Sinalização Intracelular/química , Proteínas de Membrana/química , Simulação de Acoplamento Molecular , Ligação Proteica , Técnica de Seleção de Aptâmeros , Saccharomyces cerevisiae/enzimologia , Proteínas de Saccharomyces cerevisiae/química , Alinhamento de Sequência
14.
Mar Drugs ; 17(4)2019 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-30934847

RESUMO

This study was initiated to screen for marine bacterial agents to biocontrol Magnaporthe grisea, a serious fungal pathogen of cereal crops. A bacterial strain, isolated from the cold seep in deep sea, exhibited strong growth inhibition against M. grisea, and the strain was identified and designated as Bacillus sp. CS30. The corresponding antifungal agents were purified by acidic precipitation, sequential methanol extraction, Sephadex LH-20 chromatography, and reversed phase high-performance liquid chromatography (RP-HPLC), and two antifungal peaks were obtained at the final purification step. After analysis by mass spectrometry (MS) and tandem MS, two purified antifungal agents were deduced to belong to the surfactin family, and designated as surfactin CS30-1 and surfactin CS30-2. Further investigation showed that although the antifungal activity of surfactin CS30-1 is higher than that of surfactin CS30-2, both of them induced the increased generation of reactive oxygen species (ROS) and caused serious damage to the cell wall and cytoplasm, thus leading to the cell death of M. grisea. Our results also show the differences of the antifungal activity and antifungal mechanism of the different surfactin homologs surfactin CS30-1 and surfactin CS30-2, and highlight them as potential promising agents to biocontrol plant diseases caused by M. grisea.


Assuntos
Antifúngicos/farmacologia , Bacillus/metabolismo , Lipopeptídeos/farmacologia , Magnaporthe/efeitos dos fármacos , Tensoativos/farmacologia , Antifúngicos/isolamento & purificação , Antifúngicos/metabolismo , Bactérias/metabolismo , Lipopeptídeos/biossíntese , Lipopeptídeos/isolamento & purificação , Magnaporthe/metabolismo , Doenças das Plantas/microbiologia , Doenças das Plantas/terapia , Espécies Reativas de Oxigênio/metabolismo , Tensoativos/isolamento & purificação , Tensoativos/metabolismo
15.
Org Lett ; 21(8): 2634-2638, 2019 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-30958008

RESUMO

Atrovimycin (1), a cyclodepsipeptide containing a unique vicinal-hydroxylated cinnamic acyl chain, was isolated and elucidated from Streptomyces atrovirens LQ13. The biosynthetic pathway of 1 was achieved, revealing cytochrome P450 (Avm43) and epoxide hydrolase (Avm29) enzymes constructing the vicinal-dihydroxy substitution, as well as a tailoring P450 (Avm28) enzyme catalyzing ß-hydroxylation of the l-Phe moiety. Atrovimycin shows in vitro antifungal activity and antitubercular activity against Mycobacterium tuberculosis H37Rv both in vitro (with MIC of 2.5 µg/mL) and in vivo.


Assuntos
Antifúngicos/metabolismo , Antituberculosos/metabolismo , Depsipeptídeos/biossíntese , Antituberculosos/farmacologia , Biocatálise , Vias Biossintéticas , Sistema Enzimático do Citocromo P-450/metabolismo , Depsipeptídeos/química , Epóxido Hidrolases/metabolismo , Hidroxilação , Mycobacterium tuberculosis/efeitos dos fármacos , Streptomyces/metabolismo , Relação Estrutura-Atividade
16.
Phytochemistry ; 163: 1-10, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30974396

RESUMO

Herein, five polyphenol oxidases (PPOs) obtained from Morus notabilis (Mn) were characterized. Chlorogenic acid was the most readily oxidized substrate by these MnPPOs, and the products derived from the oxidation of chlorogenic acid by MnPPOs were tested for antimicrobial activity. The results showed that products of the five MnPPOs exhibited good inhibitory effects against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Sclerotinia sclerotiorum, and Botrytis cinerea. Because the products of MnPPO1 exhibited the strongest antimicrobial activity, the antimicrobial mechanism of these products was explored. The results showed that the products of MnPPO1 increased cell membrane permeability and chitinase and ß-1,3-glucanase activities.


Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Catecol Oxidase/metabolismo , Ácido Clorogênico/farmacologia , Morus/química , Morus/enzimologia , Sequência de Aminoácidos , Antibacterianos/química , Antibacterianos/metabolismo , Antifúngicos/química , Antifúngicos/metabolismo , Ascomicetos/efeitos dos fármacos , Botrytis/efeitos dos fármacos , Catecol Oxidase/genética , Ácido Clorogênico/química , Ácido Clorogênico/metabolismo , Escherichia coli/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa/efeitos dos fármacos , Alinhamento de Sequência , Staphylococcus aureus/efeitos dos fármacos
17.
Int J Biol Macromol ; 132: 1235-1243, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-30980875

RESUMO

As the main component of the fungal cell wall, chitin has been regarded as an optimal molecular target for the biocontrol of plant-pathogenic fungi. In this study, the chitin hydrolase CcCti1, which belongs to the glycoside hydrolase family 18 (GH 18) and exhibits potential antifungal activity, was identified from Corallococcus sp. EGB. CcCti1 lacks a fibronectin type-III (FN3) domain that is present in similar enzymes from most genera of myxobacteria, indicating that CcCti1 may have acquired chitinase activity due to the FN3 domain deletion during myxobacterial evolution. CcCti1 was expressed in Escherichia coli BL21 (DE3) with a specific activity of up to 10.5 U/µmol with colloidal chitin as the substrate. Product analysis showed that CcCti1 could hydrolyze chitin into N-acetylated chitohexaose (GlcNAc)6 as the major product, in addition to chitooligosaccharides. The analysis of biochemical properties indicated that the CBD and FN3 domains in CcCti1 determine the substrate affinity and pH stability. Otherwise, CcCti1 exhibited efficient biocontrol activity against the plant pathogen Magnaporthe oryzae in a dose-dependent manner, inhibiting the conidia germination and appressoria formation at a concentration of 0.08 mg/mL. Overall, the chitohexaose-producing chitinase CcCti1 with hydrolytic features may find potential application in chitin conversion and biocontrol of fungal plant diseases.


Assuntos
Antifúngicos/metabolismo , Antifúngicos/farmacologia , Quitinases/genética , Quitinases/farmacologia , Myxococcales/efeitos dos fármacos , Sequência de Aminoácidos , Antifúngicos/química , Quitinases/química , Clonagem Molecular , Evolução Molecular , Hidrólise , Filogenia , Domínios Proteicos
18.
Food Microbiol ; 82: 160-170, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31027770

RESUMO

In the context of a demand for "preservative-free" food products, biopreservation appears as a promising alternative to either replace or reduce the use of chemical preservatives. The purpose of this study was to evaluate the antifungal activity of a collection of lactic acid bacteria (n = 194), and then to evaluate the applicability and efficacy of selected ones used as bioprotective cultures against mold spoilers in dairy and bakery products. First, lactic acid bacteria were isolated from various Algerian raw milk samples and Amoredj, a traditional fermented product. Secondly, in vitro screening tests against Mucor racemosus UBOCC-A-109155, Penicillium commune UBOCC-A-116003, Yarrowia lipolytica UBOCC-A-216006, Aspergillus tubingensis AN, Aspergillus flavus T5 and Paecilomyces formosus AT allowed for the selection of 3 active strains, namely Lactobacillus plantarum CH1, Lactobacillus paracasei B20 and Leuconostoc mesenteroides L1. In situ tests were then performed to validate their activity in actual products (sour cream and sourdough bread) challenged with fungal spoilers. These tests showed that antifungal LAB could slow the fungal target growth and could be candidates of interest for industrial applications. Finally, organic acids and various antifungal compounds produced in sour cream and sourdough bread by the selected LAB, and thus potentially supporting the observed antifungal activity, were identified and quantified by HPLC and LC-QTOF.


Assuntos
Antifúngicos/farmacologia , Laticínios/microbiologia , Microbiologia de Alimentos , Conservantes de Alimentos/farmacologia , Lactobacillales/fisiologia , Animais , Antibiose , Antifúngicos/metabolismo , Pão/microbiologia , Alimentos Fermentados/microbiologia , Conservantes de Alimentos/metabolismo , Fungos/efeitos dos fármacos , Fungos/crescimento & desenvolvimento , Lactobacillales/isolamento & purificação , Lactobacillales/metabolismo , Leite/microbiologia
19.
IET Nanobiotechnol ; 13(1): 42-45, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30964036

RESUMO

Cinnamomum camphora fruit extract was used to biosynthesise silver nanoparticles (AgNPs), and the optimised synthesis system was ascertained through solution colour change and ultraviolet-visible absorption spectra. It contained 20 ml of fruit extract, 4 mM Ag nitrate, and pH 7. AgNPs obtained based on such conditions were spherical and finely dispersed, with an average size of 20.3 nm. As-synthesised AgNPs exhibited excellent antifungal effect against Fusarium oxysporum. At a dose of 400 µg/ml of AgNPs, the inhibition rate of colony growth reached 61.00% and an IC50 value of 154.39 µg/ml. In addition, the conidia germination was totally inhibited at 100 µg/ml of AgNPs. Results of this study provide a new approach for biological control of plant pathogenic fungi, and it makes that possible for developing a brand new fungistat.


Assuntos
Antifúngicos , Cinnamomum camphora/química , Fusarium/efeitos dos fármacos , Nanopartículas Metálicas/química , Prata/farmacologia , Antifúngicos/química , Antifúngicos/metabolismo , Antifúngicos/farmacologia , Frutas/química , Química Verde , Concentração de Íons de Hidrogênio , Extratos Vegetais/química , Extratos Vegetais/metabolismo , Prata/química
20.
Braz J Microbiol ; 50(2): 481-494, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30877665

RESUMO

Fusarium crown and root rot (FCRR), caused by Fusarium oxysporum f. sp. radicis-lycopersici (FORL), is a soilborne tomato disease of increased importance worldwide. In this study, Withania somnifera was used as a potential source of biological control and growth-promoting agents. Seven fungal isolates naturally associated with W. somnifera were able to colonize tomato seedlings. They were applied as conidial suspensions or a cell-free culture filtrate. All isolates enhanced treated tomato growth parameters by 21.5-90.3% over FORL-free control and by 27.6-93.5% over pathogen-inoculated control. All tested isolates significantly decreased by 28.5-86.4% disease severity over FORL-inoculated control. The highest disease suppression, by 86.4-92.8% over control and by 81.3-88.8% over hymexazol-treated control, was achieved by the I6 isolate. FORL radial growth was suppressed by 58.5-82.3% versus control when dual cultured with tested isolates and by 61.8-83.2% using their cell-free culture filtrates. The most active agent was identified as Fusarium sp. I6 (MG835371), which displayed chitinolytic, proteolytic, and amylase activities. This has been the first report on the potential use of fungi naturally associated with W. somnifera for FCRR suppression and for tomato growth promotion. Further investigations are required in regard to mechanisms of action involved in disease suppression and plant growth promotion.


Assuntos
Antifúngicos/metabolismo , Agentes de Controle Biológico/metabolismo , Endófitos/metabolismo , Fusarium/crescimento & desenvolvimento , Lycopersicon esculentum/crescimento & desenvolvimento , Lycopersicon esculentum/microbiologia , Doenças das Plantas/prevenção & controle , Withania/microbiologia , Amilases/metabolismo , Quitinases/metabolismo , Doenças das Plantas/microbiologia , Folhas de Planta/microbiologia , Raízes de Plantas/microbiologia , Caules de Planta/microbiologia , Proteólise
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