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1.
Braz. j. microbiol ; 48(3): 410-418, July-Sept. 2017. tab, graf
Article in English | LILACS | ID: biblio-889127

ABSTRACT

Abstract Chaetoglobosin A is an antibacterial compound produced by Chaetomium globosum, with potential application as a biopesticide and cancer treatment drug. The aim of this study was to evaluate the feasibility of utilizing cornstalks to produce chaetoglobosin A by C. globosum W7 in solid-batch fermentation and to determine an optimal method for purification of the products. The output of chaetoglobosin A from the cornstalks was 0.34 mg/g, and its content in the crude extract was 4.80%. Purification conditions were optimized to increase the content of chaetoglobosin A in the crude extract, including the extract solvent, temperature, and pH value. The optimum process conditions were found to be acetone as the extractant, under room temperature, and at a pH value of 13. Under these conditions, a production process of the antifungal chaetoglobosin A was established, and the content reached 19.17%. Through further verification, cornstalks could replace crops for the production of chaetoglobosin A using this new production process. Moreover, the purified products showed great inhibition against Rhizoctonia solani, with chaetoglobosin A confirmed as the main effective constituent (IC50 = 3.88 µg/mL). Collectively, these results demonstrate the feasibility of using cornstalks to synthesize chaetoglobosin A and that the production process established in this study was effective.


Subject(s)
Industrial Microbiology/methods , Callosities/microbiology , Chaetomium/metabolism , Indole Alkaloids/metabolism , Antifungal Agents/metabolism , Waste Products/analysis , Industrial Microbiology/instrumentation , Callosities/metabolism , Molecular Structure , Plant Stems/metabolism , Plant Stems/microbiology , Indole Alkaloids/isolation & purification , Indole Alkaloids/chemistry , Antifungal Agents/isolation & purification , Antifungal Agents/chemistry
2.
Braz. j. microbiol ; 47(4): 955-964, Oct.-Dec. 2016. tab, graf
Article in English | LILACS | ID: biblio-828202

ABSTRACT

Abstract The possible application of a bacterial strain - Bacillus subtilis R1, isolated from an oil contaminated desert site in India, as biocontrol agent and its biosurfactant in microbial enhanced oil recovery are discussed. The biosurfactant production in minimal medium was carried out at different temperatures and salt concentrations, where it produced an efficient biosurfactant at 30-45 °C and in presence of up to 7% salt. It significantly reduced the surface tension from 66 ± 1.25 mN/m to 29 ± 0.85 mN/m within 24 h. In order to enhance the biosurfactant production, random mutagenesis of B. subtilis R1 was performed using chemical mutagen - ethyl methanesulfonate. Majority of the isolated 42 mutants showed biosurfactant production, but the difference was statistically insignificant as compared with parent strain R1. Therefore none of the mutants were selected for further study, and only parent strain R1 was studied. The biosurfactant was quite stable under harsh conditions for up to 10 days. The biosurfactant was extracted and characterized as similar to the lipopeptide group - surfactins and fengycin. The crude oil displacement experiments using biosurfactant broth in sand pack glass columns showed 33 ± 1.25% additional oil recovery. The strain also showed inhibition of various plant pathogenic fungi on potato dextrose agar medium.


Subject(s)
Bacillus subtilis/metabolism , Lipopeptides/biosynthesis , Surface-Active Agents/metabolism , Surface-Active Agents/pharmacology , Bacillus subtilis/classification , Bacillus subtilis/genetics , RNA, Ribosomal, 16S/genetics , Microbial Sensitivity Tests , Mutagenesis , Spectroscopy, Fourier Transform Infrared , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Lipopeptides/pharmacology , Metabolic Engineering , Hydrogen-Ion Concentration , Antifungal Agents/metabolism , Antifungal Agents/pharmacology
3.
Braz. j. microbiol ; 47(2): 480-488, Apr.-June 2016. tab, graf
Article in English | LILACS | ID: lil-780842

ABSTRACT

Abstract The aim of this paper is to identify and investigate an endophytic fungus (strain 28) that was isolated from Houttuynia cordata Thunb, a famous and widely-used Traditional Chinese Medicine. Based on morphological methods and a phylogenetic analysis of ITS sequences, this strain was identified as Chaetomium globosum. An antifungal activity bioassay demonstrated that the crude ethyl acetate (EtOAc) extracts of strain 28 had a wide antifungal spectrum and strong antimicrobial activity, particularly against Exserohilum turcicum (Pass.) Leonard et Suggs, Botrytis cinerea persoon and Botrytis cinerea Pers. ex Fr. Furthermore, the fermentation conditions, extraction method and the heat stability of antifungal substances from strain 28 were also studied. The results showed that optimal antifungal activity can be obtained with the following parameters: using potato dextrose broth (PDB) as the base culture medium, fermentation for 4–8 d (initial pH: 7.5), followed by extraction with EtOAc. The extract was stable at temperatures up to 80 °C. This is the first report on the isolation of endophytic C. globosum from H. cordata to identify potential alternative biocontrol agents that could provide new opportunities for practical applications involving H. cordata.


Subject(s)
Chaetomium/isolation & purification , Chaetomium/metabolism , Houttuynia/microbiology , Endophytes/metabolism , Antifungal Agents/metabolism , Phylogeny , Chaetomium/classification , Chaetomium/genetics , Endophytes/isolation & purification , Endophytes/classification , Endophytes/genetics , Fungi/growth & development , Fungi/drug effects , Antifungal Agents/pharmacology
4.
Braz. j. microbiol ; 47(1): 33-38, Jan.-Mar. 2016. tab, graf
Article in English | LILACS | ID: lil-775105

ABSTRACT

Abstract Since, there is no study reporting the mechanism of azole resistance among yeasts isolated from aquatic environments; the present study aims to investigate the occurrence of antifungal resistance among yeasts isolated from an aquatic environment, and assess the efflux-pump activity of the azole-resistant strains to better understand the mechanism of resistance for this group of drugs. For this purpose, monthly water and sediment samples were collected from Catú Lake, Ceará, Brazil, from March 2011 to February 2012. The obtained yeasts were identified based on morphological and biochemical characteristics. Of the 46 isolates, 37 were Candida spp., 4 were Trichosporon asahii, 3 were Cryptococcus laurentii, 1 Rhodotorula mucilaginosa, and 1 was Kodamaea ohmeri. These isolates were subjected to broth microdilution assay with amphotericin B, itraconazole, and fluconazole, according to the methodology standardized by the Clinical and Laboratory Standards Institute (CLSI). The minimum inhibitory concentrations (MICs) of amphotericin B, itraconazole, and fluconazole were 0.03125–2 µg/mL, 0.0625 to ≥16 µg/mL, and 0.5 to ≥64 µg/mL, respectively, and 13 resistant azole-resistant Candida isolates were detected. A reduction in the azole MICs leading to the phenotypical reversal of the azole resistance was observed upon addition of efflux-pump inhibitors. These findings suggest that the azole resistance among environmental Candida spp. is most likely associated with the overexpression of efflux-pumps.


Subject(s)
Antifungal Agents/metabolism , Azoles/metabolism , Candida/drug effects , Candida/isolation & purification , Drug Resistance, Fungal , Lakes/microbiology , Biological Transport, Active , Brazil , Microbial Sensitivity Tests
5.
Bol. latinoam. Caribe plantas med. aromát ; 15(1): 1-17, ene. 2016. ilus, graf, tab
Article in English | LILACS | ID: biblio-907513

ABSTRACT

The direct in vitro fungitoxicity and metabolism of safrole and dillapiole (isolated from Piper auritum and Piper holtonii, respectively) by Botryodiplodia theobromae and Colletotrichum acutatum were investigated. Higher values of mycelial growth inhibition for both fungi were obtained for dillapiole, as compared with safrole. B. theobromae was able to metabolize both compounds to their respective vicinal diols, reaching 65 percent relative abundance during the biotransformation of dillapiole; while C. acutatum only transformed safrole to various metabolites with relative abundances under 5 percent. According to the low antifungal activity of the major metabolic products (< 5 percent for vicinal diols), a detoxification process was implied. Studies on the influence of some substituents in the aromatic ring of safrole and dillapiole on the antifungal activity against B. theobromae were also carried out. As result, the safrole nitrated derivative, 6-nitrosafrole, showed a fungitoxicity level similar to that displayed by the commercial fungicide Carbendazim® under the conditions used. In light of this, safrole and dillapiole could be suggested as feasible structural templates for developing new antifungal agents.


Se investigó la fungitoxicidad directa in vitro y el metabolismo de safrol y dilapiol (obtenidos desde Piper auritum and Piper holtonii, respectivamente) por Botryodiplodia theobromae y Colletotrichum acutatum. Los valores mayores de inhibición del crecimiento micelial de ambos hongos se obtuvieron para dilapiol, en comparación con safrol. B. theobromae metabolizó ambos compuestos a sus respectivos dioles vecinales, alcanzando abundancias relativas del 65 por ciento durante la biotransformación del dilapiol; mientras que C. acutatum solo transformó safrol en varios metabolitos con abundancias relativas menores al 5 por ciento. De acuerdo con la baja actividad antifúngica de los productos metabólicos mayoritarios (< 5 por ciento para los dioles vecinales), se sugiere un proceso de desintoxicación. Adicionalmente, se evaluó la influencia de algunos sustituyentes en el anillo aromático de safrol y dilapiol sobre la actividad antifúngica contra B. theobromae. Como resultado, el derivado nitrado del safrol, el 6–nitro safrol, presentó un nivel de fungitoxicidad similar al exhibido por el fungicida comercial Carbendazim® bajo las condiciones usadas. A la luz de lo anterior, safrol y dilapiol podrían ser sugeridos como plantillas estructurales adecuadas para el desarrollo de nuevos agentes antifúngicos.


Subject(s)
Antifungal Agents/pharmacology , Dioxoles/pharmacology , Mitosporic Fungi , Safrole/pharmacology , Antifungal Agents/metabolism , Biotransformation , Colletotrichum , Dioxoles/metabolism , In Vitro Techniques , Safrole/metabolism
6.
Mem. Inst. Oswaldo Cruz ; 110(8): 1003-1009, Dec. 2015. tab, graf
Article in English | LILACS | ID: lil-769825

ABSTRACT

An investigation was carried out into the genetic mechanisms responsible for multidrug resistance in nine carbapenem-resistant Pseudomonas aeruginosaisolates from different hospitals in Recife, Brazil. Susceptibility to antimicrobial agents was determined by broth microdilution. Polymerase chain reaction (PCR) was employed to detect the presence of genes encoding β-lactamases, aminoglycoside-modifying enzymes (AMEs), 16S rRNA methylases, integron-related genes and OprD. Expression of genes coding for efflux pumps and AmpC cephalosporinase were assessed by quantitative PCR. The outer membrane proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The blaSPM-1, blaKPC-2 and blaGES-1 genes were detected in P. aeruginosaisolates in addition to different AME genes. The loss of OprD in nine isolates was mainly due to frameshift mutations, premature stop codons and point mutations. An association of loss of OprD with the overexpression of MexAB-OprM and MexXY-OprM was observed in most isolates. Hyper-production of AmpC was also observed in three isolates. Clonal relationship of the isolates was determined by repetitive element palindromic-PCR and multilocus sequence typing. Our results show that the loss of OprD along with overexpression of efflux pumps and β-lactamase production were responsible for the multidrug resistance in the isolates analysed.


Subject(s)
Humans , Carbapenems/metabolism , Drug Resistance, Multiple, Bacterial/genetics , Mutation , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/genetics , beta-Lactam Resistance/genetics , beta-Lactamases/metabolism , Aminoglycosides/metabolism , Amphotericin B/analogs & derivatives , Amphotericin B/metabolism , Antifungal Agents/metabolism , Brazil , Cephalosporinase/classification , Cephalosporinase/metabolism , Codon, Nonsense/metabolism , Enzyme Activation/genetics , Frameshift Mutation/genetics , Gene Expression Regulation, Bacterial/genetics , Membrane Transport Proteins/metabolism , Methyltransferases/metabolism , Nucleotidyltransferases/metabolism , Point Mutation/genetics , Porins/metabolism , Pseudomonas aeruginosa/enzymology , Pseudomonas aeruginosa/isolation & purification , Repetitive Sequences, Nucleic Acid , beta-Lactamases/genetics
7.
Braz. j. microbiol ; 46(2): 359-366, Apr-Jun/2015. tab, graf
Article in English | LILACS | ID: lil-749714

ABSTRACT

Endophytes are being considered for use in biological control, and the enzymes they secrete might facilitate their initial colonization of internal plant tissues and direct interactions with microbial pathogens. Microbial proteases are also biotechnologically important products employed in bioremediation processes, cosmetics, and the pharmaceutical, photographic and food industries. In the present study, we evaluated antagonism and competitive interactions between 98 fungal endophytes and Alternaria alternata, Colletotrichum sp., Phyllosticta citricarpa and Moniliophthora perniciosa. We also examined the proteolytic activities of endophytes grown in liquid medium and conducted cup plate assays. The results showed that certain strains in the assemblage of P. hispidum endophytes are important sources of antifungal properties, primarily Lasiodiplodia theobromae JF766989, which reduced phytopathogen growth by approximately 54 to 65%. We detected 28 endophytes producing enzymatic halos of up to 16.40 mm in diameter. The results obtained in the present study highlight the proteolytic activity of the endophytes Phoma herbarum JF766995 and Schizophyllum commune JF766994, which presented the highest enzymatic halo diameters under at least one culture condition tested. The increased activities of certain isolates in the presence of rice or soy flour as a substrate (with halos up to 17.67 mm in diameter) suggests that these endophytes have the potential to produce enzymes using agricultural wastes.


Subject(s)
Antifungal Agents/metabolism , Endophytes/isolation & purification , Endophytes/metabolism , Fungi/isolation & purification , Fungi/metabolism , Peptide Hydrolases/metabolism , Piper/microbiology , DNA, Fungal/chemistry , DNA, Fungal/genetics , DNA, Ribosomal Spacer/chemistry , DNA, Ribosomal Spacer/genetics , Fungi/classification , Fungi/drug effects , Microbiological Techniques , Molecular Sequence Data , Sequence Analysis, DNA
8.
Rev. argent. microbiol ; 47(2): 118-124, June 2015. ilus, tab, graf
Article in English | LILACS | ID: lil-757148

ABSTRACT

In this study, we analyzed the conservation of a semi-liquid bio-preserver (SL778) developed with Lactobacillus plantarum CRL 778, a lactic acid bacterium (LAB) having antifungal activity. The characteristics of the SL778 starter remained stable during a 14-day storage at 4 °C. At −20 °C, cell viability and organic acid concentration showed a significant (p < 0.05) decrease after 7 days. These differences observed between the storage temperatures tested were reflected in the acidification activity of SL778 during dough fermentation. However, SL778 maintained its antifungal efficacy up to a 14-day storage at both temperatures. Sensory attributes (acidic and spicy tastes and acidic smell) of breads manufactured with starter SL778 (stored at 4 or −20 °C) were evaluated. No undesirable difference was detected with respect to bread control without SL778 and bread manufactured with SL778 (stored at 4 or −20 °C). In conclusion, the SL778 semi-liquid bio-preserver can be stored at 4 or −20 °C without modifying its antifungal activity during 14 days.


Se evaluó la estabilidad de un bioconservante semilíquido destinado a panificados envasados, desarrollado con la bacteria láctica con actividad antifúngica Lactobacillus plantarum CRL 778. Las características del bioconservante, designado como SL778, se mantuvieron estables durante 14 días de almacenamiento a 4 °C. A -20 °C, la viabilidad celular y la concentración de ácidos orgánicos disminuyeron significativamente (p < 0,05) después de 7 días de almacenamiento. Estas diferencias según la temperatura de almacenamiento se reflejaron en la actividad acidificante de SL778 durante la fermentación de las masas. Sin embargo, SL778 mantuvo su eficacia antifúngica por hasta 14 días con el almacenamiento a ambas temperaturas. Se evaluaron los atributos sensoriales de los panificados elaborados con SL778 (gusto ácido y picante y olor ácido) tras el almacenamiento a las dos temperaturas. En tal sentido, los panelistas no detectaron diferencias que vuelvan al producto indeseable al comparar los panificados control (sin SL778) y los elaborados con SL778, tanto almacenados a 4 °C como a -20 °C. En conclusión, el bioconservante semilíquido SL778 se puede almacenar a 4 °C o a -20 °C durante 14 días sin que ocurran cambios en su actividad antifúngica.


Subject(s)
Humans , Antifungal Agents/metabolism , Bread/microbiology , Food Microbiology , Food Preservation/methods , Food Storage/methods , Lactobacillus plantarum/metabolism , Cooking , Fermentation , Food Preferences , Fast Foods/microbiology , Fungi/growth & development , Fungi/isolation & purification , Hydrogen-Ion Concentration
9.
Mem. Inst. Oswaldo Cruz ; 109(2): 220-228, abr. 2014. tab, graf
Article in English | LILACS | ID: lil-705813

ABSTRACT

The microbial synthesis of nanoparticles is a green chemistry approach that combines nanotechnology and microbial biotechnology. The aim of this study was to obtain silver nanoparticles (SNPs) using aqueous extract from the filamentous fungus Fusarium oxysporum as an alternative to chemical procedures and to evaluate its antifungal activity. SNPs production increased in a concentration-dependent way up to 1 mM silver nitrate until 30 days of reaction. Monodispersed and spherical SNPs were predominantly produced. After 60 days, it was possible to observe degenerated SNPs with in additional needle morphology. The SNPs showed a high antifungal activity against Candida and Cryptococcus , with minimum inhibitory concentration values ≤ 1.68 µg/mL for both genera. Morphological alterations of Cryptococcus neoformans treated with SNPs were observed such as disruption of the cell wall and cytoplasmic membrane and lost of the cytoplasm content. This work revealed that SNPs can be easily produced by F. oxysporum aqueous extracts and may be a feasible, low-cost, environmentally friendly method for generating stable and uniformly sized SNPs. Finally, we have demonstrated that these SNPs are active against pathogenic fungi, such as Candida and Cryptococcus .


Subject(s)
Antifungal Agents/metabolism , Candida/drug effects , Cryptococcus/drug effects , Fusarium/metabolism , Metal Nanoparticles , Silver/metabolism , Antifungal Agents/therapeutic use , Cell Extracts , Candida/classification , Candida/ultrastructure , Cryptococcus/classification , Cryptococcus/ultrastructure , Disk Diffusion Antimicrobial Tests , Growth Inhibitors , Microbial Sensitivity Tests , Microscopy, Atomic Force , Microscopy, Electron, Transmission , Metal Nanoparticles/therapeutic use , Silver/analysis , Silver/therapeutic use
10.
Braz. j. microbiol ; 45(1): 287-293, 2014. ilus, tab
Article in English | LILACS | ID: lil-709489

ABSTRACT

To optimize the medium for high zofimarin production, sucrose maltose, glucose, tryptone and peptone were used in an orthogonal array design experiment, where the highest value of zofimarin produced was 25.6 µg/mL. This value was about 3 times higher than that obtained with Czapek yeast extract (CzYE) culture medium. A study with Plackett-Burman design showed that sucrose, maltose, glucose and NaNO3 were significant factors in zofimarin production. Further studies using central composite design (CCD) showed the significance of glucose and the interactions of these critical components affecting zofimarin production. Multiple regression analysis of the data yielded a poor fit as shown by the mismatch of the model with these variable factors. When a polynomial equation was applied, the maximum zofimarin production was predicted to be 201.9 µg/mL. Experimental verification yielded a much lower amount of zofimarin, at around 70 µg/mL. Reconsideration of the CCD data and repetition of some runs with high zofimarin production resulted in reproducible zofimarin yield at 79.7 µ/mL. Even though the amount was lower than the predicted value, the medium optimization study was considered to be quite successful as the yield increased to around 8 times that obtained with the original CzYE culture medium.


Subject(s)
Antifungal Agents/metabolism , Culture Media/chemistry , Endophytes/metabolism , Xylariales/metabolism , Indenes/metabolism
11.
Braz. j. microbiol ; 44(2): 649-655, 2013. ilus, tab
Article in English | LILACS | ID: lil-688596

ABSTRACT

This study aims at evaluating the effects of Zataria multiflora (Z. multiflora) essential oil (EO) on growth, aflatoxin production and transcription of aflatoxin biosynthesis pathway genes. Total RNAs of Aspergillus parasiticus (A.parasiticus) ATCC56775 grown in yeast extract sucrose (YES) broth medium treated with Z. multiflora EO were subjected to reverse transcription-polymerase chain reaction (RT-PCR). Specific primers of nor-1, ver-1, omt-A and aflR genes were used. In parallel mycelial dry weight of samples were measured and all the media were assayed by high-pressure liquid chromatography (HPLC) for aflatoxinB1 (AFB1), aflatoxinB2 (AFB2), aflatoxinG1 (AFG1), aflatoxinG2 (AFG2) and aflatoxin total (AFTotal) production. The results showed that mycelial dry weight and aflatoxin production reduce in the presence of Z. multiflora EO (100 ppm) on day 5 of growth. It was found that the expression of nor-1, ver-1, omt-A and aflR genes was correlated with the ability of fungus to produce aflatoxins on day 5 in YES medium. RT-PCR showed that in the presence of Z.multiflora EO (100 ppm) nor-1, ver-1 and omtA genes expression was reduced. It seems that toxin production inhibitory effects of Z. multiflora EO on day 5 may be at the transcription level and this herb may cause reduction in aflatoxin biosynthesis pathway genes activity.


Subject(s)
Aflatoxins/biosynthesis , Antifungal Agents/metabolism , Aspergillus/drug effects , Biosynthetic Pathways/drug effects , Lamiaceae/chemistry , Oils, Volatile/metabolism , Transcription, Genetic/drug effects , Antifungal Agents/isolation & purification , Aspergillus/genetics , Aspergillus/growth & development , Aspergillus/metabolism , Biosynthetic Pathways/genetics , Chromatography, High Pressure Liquid , Gene Expression Profiling , Oils, Volatile/isolation & purification , Reverse Transcriptase Polymerase Chain Reaction
12.
Braz. j. microbiol ; 43(1): 224-229, Jan.-Mar. 2012. tab
Article in English | LILACS | ID: lil-622806

ABSTRACT

Our purpose was to determine the anti-Mycobacterium tuberculosis activity of the metabolites produced by the endophitic fungus Phomopsis stipata (Lib.) B. Sutton, (Diaporthaceae), cultivated in different media. The antimycobacterial activity was assessed through the Resazurin Microtiter Assay (REMA) and the cytotoxicity test performed on macrophage cell line. The extracts derived from fungi grown on Corn Medium and Potato Dextrose Broth presented the smallest values of Minimum Inhibitory Concentration (MIC) and low cytotoxicity, which implies a high selectivity index. This is the first report on the chemical composition and antitubercular activity of metabolites of P. stipata, as well as the influence of culture medium on these properties.


Subject(s)
Antifungal Agents/metabolism , In Vitro Techniques , Mycobacterium Infections , Macrophages, Alveolar/metabolism , Mycobacterium tuberculosis/isolation & purification , Mycobacterium tuberculosis/metabolism , Diagnostic Techniques and Procedures , Methodology as a Subject
13.
Electron. j. biotechnol ; 8(3)Dec. 2005. tab, ilus
Article in English | LILACS | ID: lil-448791

ABSTRACT

Trichoderma harzianum 650 (Th650) and Paenebacillus lentimorbus 629 (Pl629) selected earlier for their ability to control Rhizoctonia solani, Fusarium solani and F. oxysporum in vitro, were applied alone or combined with solarization (summer assay) and/or with methyl bromide (MeBr) (summer and winter assays) to a soil with a high inoculum level, for the control of tomato root rot caused by the complex F. oxysporum f. sp. lycopersici - Pyrenochaeta lycopersici - Rhizoctonia solani. Evaluations were also performed independently for root damage caused by P. lycopersici, and also for R. solani in the summer assay. MeBr decreased tomato root damage caused by the complex from 88.7 percent to 21.2 percent and from 78.4 percent to 35.7 percent in the summer and in the winter assay, respectively. None of the bio-controllers could replace MeBr in the winter assay, but Th650 and Pl629 reduced root damage caused by this complex in the summer assay. Treatments with bio-controllers were improved by their combination with solarization in this season. Independent evaluations showed that the positive control of Th650 towards R. solani and the lack of effect on P. lycopersici correlates well with the endochitinase pattern expressed by Th650 in response to these phytopathogens. Root damage caused by R. solani can be controlled at a similar level as it does MeBr in summer assays, thus representing an alternative to the use of this chemical fungicide for the control of this phytopathogen.


Subject(s)
Antifungal Agents/metabolism , Pest Control, Biological/methods , Fusarium/metabolism , Lycopersicon esculentum/microbiology , Rhizoctonia/metabolism , Bacillus/metabolism , Greenhouses , Hydrocarbons, Brominated , Mitosporic Fungi/metabolism , Models, Biological , Plant Roots/microbiology , Seasons , Soil Microbiology , Sunlight , Trichoderma/metabolism
14.
Braz. j. med. biol. res ; 38(11): 1585-1592, Nov. 2005.
Article in English | LILACS | ID: lil-414712

ABSTRACT

Lactococcus lactis, the model lactic acid bacterium, is a good candidate for heterologous protein production in both foodstuffs and the digestive tract. We attempted to produce Streptomyces tendae antifungal protein 1 (Afp1) in L. lactis with the objective of constructing a strain able to limit fungal growth. Since Afp1 activity requires disulfide bond (DSB) formation and since intracellular redox conditions are reportedly unfavorable for DSB formation in prokaryotes, Afp1 was produced as a secreted form. An inducible expression-secretion system was used to drive Afp1 secretion by L. lactis; Afp1 was fused or not with LEISSTCDA, a synthetic propeptide (LEISS) that has been described to be a secretion enhancer. Production of Afp1 alone was not achieved, but production of LEISS-Afp1 was confirmed by Western blot and immunodetection with anti-Afp1 antibodies. This protein (molecular mass: 9.8 kDa) is the smallest non-bacteriocin heterologous protein ever reported to be secreted in L. lactis via the Sec-dependent pathway. However, no anti-fungal activity was detected, even in concentrated samples of induced supernatant. This could be due to a too low secretion yield of Afp1 in L. lactis, to the absence of DSB formation, or to an improper DSB formation involving the additional cysteine residue included in LEISS propeptide. This raises questions about size limits, conformation problems, and protein secretion yields in L. lactis.


Subject(s)
Lactococcus lactis/metabolism , Bacterial Proteins , Carrier Proteins , Antifungal Agents/isolation & purification , Antifungal Agents/metabolism , Antifungal Agents/pharmacology , Aspergillus fumigatus/drug effects , Blotting, Western , Microbial Sensitivity Tests , Paecilomyces/drug effects , Plasmids/genetics , Bacterial Proteins/genetics , Bacterial Proteins/pharmacology , Carrier Proteins/genetics , Carrier Proteins/pharmacology , Trichophyton/drug effects
15.
Rev. ciênc. farm. básica apl ; 26(1): 29-37, 2005. tab
Article in Portuguese | LILACS | ID: lil-425721

ABSTRACT

Com o aumento significativo na incidência de infecções fúngicas invasivas durante a última década, principalmente em pacientes com câncer, AIDS, ou hospitalizados por período prolongado em unidades de terapia intensiva, há a necessidade da pesquisa de novos agentes antifúngicos com qualidade superior aos existentes. Esta pesquisa objetivou a procura de um microrganismo produtor de substâncias antibacterianas e antifúngicas. Microrganismos das amostras de solo da região de Araraquara, Brasil, foram coletados e analisados quanto ao seu potencial antimicrobiano contra microrganismos padrões (Staphylococcus aureus, Escherichia coli, Candida albicans, Aspergillus oryzae). Das 64 cepas isoladas, 34 apresentaram atividade antimicrobiana. A cepa Ar 4014 foi escolhida para dar continuidade ao trabalho por apresentar boa atividade antimicrobiana contra Candida albicans. Estudos fermentativos mostraram que os Meios 608-K e 602-B foram os melhores para produção e extração de substâncias antifúngicas de Ar 4014. Após cromatografia em coluna de sílica do extrato bruto, as frações ativas obtidas mostraram picos de absorção UV-VIS característicos de pentaenos normais. O antibiótico foi denominado provisoriamente Ara 4014-75


Subject(s)
Animals , Antifungal Agents , Anti-Bacterial Agents/metabolism , Antifungal Agents/isolation & purification , Antifungal Agents/metabolism , Streptomycin/isolation & purification , Streptomyces/isolation & purification , Streptomyces/metabolism , Aspergillus oryzae/isolation & purification , Candida albicans/isolation & purification , Escherichia coli/isolation & purification , Staphylococcus aureus/isolation & purification
16.
J Biosci ; 2001 Sep; 26(3): 333-9
Article in English | IMSEAR | ID: sea-111090

ABSTRACT

CaMDR1 encodes a major facilitator superfamily (MFS) protein in Candida albicans whose expression has been linked to azole resistance and which is frequently encountered in this human pathogenic yeast. In this report we have overexpressed CaMdr1p in Sf9 insect cells and demonstrated for the first time that it can mediate methotrexate (MTX) and fluconazole (FLC) transport. MTX appeared to be a better substrate for CaMdr1p among these two tested drugs. Due to severe toxicity of these drugs to insect cells, further characterization of CaMdr1p as a drug transporter could not be done with this system. Therefore, as an alternative, CaMdr1p and Cdr1p, which is an ABC protein (ATP binding cassette) also involved in azole resistance in C. albicans, were independently expressed in a common hypersensitive host JG436 of Saccharomyces cerevisiae. This allowed a better comparison between the functionality of the two export pumps. We observed that while both FLC and MTX are effluxed by CaMdr1p, MTX appeared to be a poor substrate for Cdr1p. JG436 cells expressing Cdr1p thus conferred resistance to other antifungal drugs but remained hypersensitive to MTX. Since MTX is preferentially transported by CaMdr1p, it can be used for studying the function of this MFS protein.


Subject(s)
Antifungal Agents/metabolism , Antimetabolites, Antineoplastic/metabolism , Binding Sites , Biological Transport , Candida albicans/drug effects , Cell Line , Cloning, Molecular , Drug Resistance, Multiple, Fungal/physiology , Fluconazole/metabolism , Humans , Methotrexate/metabolism , ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics , Transformation, Genetic
17.
Rev. argent. microbiol ; 32(3): 157-160, jul.-sept. 2000.
Article in Spanish | LILACS | ID: lil-332520

ABSTRACT

Severe mycotic infections are a source of concern in immunocompromised patients or in those who receive chemotherapy for hematological malignant diseases. One of the causes is referred to the appearance of antimycotic resistant microorganisms. Fluconazole is one of the antimycotic used for invasive mycoses treatment. Therefore it is necessary to evaluate the factors that originate this resistance. In the present report the yeast Saccharomyces cerevisiae S288c was used as a model system. In resistant strains the accumulation of the lipophilic cation Rhodamine 6G, L-leucine uptake and growth inhibition by crystal violet dye were determined. The results presented herein demonstrate the correlation between the membrane potential and the resistance to fluconazole presented by S. cerevisiae strain S288c.


Subject(s)
Antifungal Agents/pharmacology , Fluconazole , Membrane Potentials , Drug Resistance, Microbial , Rhodamines , Saccharomyces cerevisiae , Antifungal Agents/metabolism , Culture Media , Sterols/metabolism , Fluconazole , Gentian Violet , Leucine , Membrane Lipids/metabolism , Proline , Saccharomyces cerevisiae
18.
Arq. ciências saúde UNIPAR ; 3(1): 29-33, jan.-abr. 1999. tab, graf
Article in Portuguese | LILACS | ID: lil-325125

ABSTRACT

Metabólitos do fungo entomopatogênico Nomuraea rileyi produzidos em culturas submersas em caldo Sabouraud sacarose extrato de levedura foram extraídos com diclorometano. O extrato bruto foi fracionado por cromatografia em coluna e em camada espessa de fluxo contínuo utilizando benzeno-clorofórmio-acetato de etila 18:1:1 (v:v:v) como eluentes. Amostras de Saccharomyces cerevisiae e de bactérias (18 cepas hospitalares e 5 estirpes fitopatogênicas) foram testadas frente ao metabólito empregando-se o método de difusäo em ágar pelo sistema de discos (Kirby-Bauer). Aproximadamente (40 por cento) (9/23) das amostras bacterianas ensaiadas tiveram seu crescimento inibido na presença do metabólito produzido pelo fungo Nomuraea rileyi, sugerindo uma possível atividade antibacteriana deste metabólito


Subject(s)
Antifungal Agents/metabolism , Gram-Negative Bacteria/growth & development , Gram-Positive Bacteria/growth & development , Mitosporic Fungi/isolation & purification , Mycotoxins
19.
Rev. microbiol ; 20(4): 490-4, out.-dez. 1989. tab
Article in Portuguese | LILACS | ID: lil-97154

ABSTRACT

Foi estudada, "in vitro", a atividade antifúngica de cinco anti-sépticos contra leveduras isoladas antes e durante a radioterapia de pacientes de carcinoma epidermóide de boca. A concentraçäo inibitória mínima do triclosan variou de < ou = 0,07 g/L a 20 > g/L, conforme a cepa estudada, enquanto que a dos outros anti-sépticos foi invariavelemente < ou = 0,07 g/L. O hexaclorofeno e o timerosal foram fungicidas também em concentraçöes < ou = 0,7 g/L para todas as leveduras avaliadas, e o cloreto de cetilpiridino o foi a 0;31 g/L. Em concentraçöes de até 20g/L, o triclosan näo demonstrou atividade fungicida contra a maior parte das leveduras, e a violeta de genciana näo foi letal somente para duas cepas de C. albicans isoladas de pacientes que se encontravam sob radioterapia


Subject(s)
Antifungal Agents/metabolism , Candida albicans/isolation & purification , Carcinoma, Squamous Cell/radiotherapy , In Vitro Techniques , Mouth Neoplasms/radiotherapy , Yeasts/isolation & purification , Candida albicans/classification , Carcinoma, Squamous Cell/microbiology , Mouth Neoplasms/microbiology
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