RESUMO
Mycocins have demonstrated inhibition of fungi, bacteria, parasites and viruses, in addition to being studied as epidemiological markers and in the development of vaccines. They are defined as extracellular proteins or glycoproteins with different activities, the main mechanism of action being the inhibition of ß-glucan synthesis in the cell wall of sensitive strains. Given the resistance problems created by several microorganisms to agents commonly used in clinical practice, the discovery of new substances with this purpose becomes essential. Mycocins have potential as anti-microbials because they show minimal toxicity and do not present resistance.
Assuntos
Anti-Infecciosos/farmacologia , Proteínas Fúngicas/farmacologia , Micotoxinas/farmacologia , Leveduras/química , Animais , Anti-Infecciosos/química , Bactérias/efeitos dos fármacos , Parede Celular/efeitos dos fármacos , Proteínas Fúngicas/química , Humanos , Camundongos , Parasitos/efeitos dos fármacos , Vírus/efeitos dos fármacos , Leveduras/metabolismoRESUMO
Trichothecene mycotoxins are recognized as highly bioactive compounds that can be used in the design of new useful bioactive molecules. In Trichoderma brevicompactum, the first specific step in trichothecene biosynthesis is carried out by a terpene cyclase, trichodiene synthase, that catalyzes the conversion of farnesyl diphosphate to trichodiene and is encoded by the tri5 gene. Overexpression of tri5 resulted in increased levels of trichodermin, a trichothecene-type toxin, which is a valuable tool in preparing new molecules with a trichothecene skeleton. In this work, we developed the hemisynthesis of trichodermin and trichodermol derivatives in order to evaluate their antimicrobial and cytotoxic activities and to study the chemo-modulation of their bioactivity. Some derivatives with a short chain at the C-4 position displayed selective antimicrobial activity against Candida albicans and they showed MIC values similar to those displayed by trichodermin. It is important to highlight the cytotoxic selectivity observed for compounds 9, 13, and 15, which presented average IC50 values of 2 µg/mL and were cytotoxic against tumorigenic cell line MCF-7 (breast carcinoma) and not against Fa2N4 (non-tumoral immortalized human hepatocytes).
Assuntos
Tricodermina/análogos & derivados , Animais , Antibacterianos/síntese química , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Antifúngicos/síntese química , Antifúngicos/metabolismo , Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Linhagem Celular , Feminino , Hepatócitos/efeitos dos fármacos , Humanos , Células MCF-7 , Micotoxinas/farmacologia , Coelhos , Trichoderma/enzimologia , Trichoderma/genética , Trichoderma/metabolismo , Tricodermina/síntese química , Tricodermina/química , Tricodermina/farmacologiaRESUMO
Micophenolic acid (MPA) is an immunosuppressant mycotoxin which impairs yeast cell growth to variable degrees depending on the genetic background. Such variation could have emerged from several phenomena, including MPA gene resistance mutations and variations in copy number and localisation of resistance genes. To test this, we evaluated MPA susceptibility in four S. cerevisiae isolates and genetically dissected variation through the identification of Quantitative Trait Loci. Via linkage analysis we identified six QTLs, majority of which were located within subtelomeres and co-localised with IMD2, an inosine monophosphate dehydrogenase previously identified underlying MPA drug resistance in yeast cells. From chromosome end disruption and bioinformatics analysis, it was found that the subtelomere localisation of IMD2 within chromosome ends is variable depending on the strain, demonstrating the influence of IMD2 on the natural variation in yeast MPA susceptibility. Furthermore, GxE gene expression analysis of strains exhibiting opposite phenotypes indicated that ribosome biogenesis, RNA transport, and purine biosynthesis were impaired in strains most susceptible to MPA toxicity. Our results demonstrate that natural variation can be exploited to better understand the molecular mechanisms underlying mycotoxin susceptibility in eukaryote cells and demonstrate the role of subtelomeric regions in mediating interactions with the environment.
Assuntos
Farmacorresistência Fúngica/genética , Micotoxinas/farmacologia , Saccharomycetales/efeitos dos fármacos , Saccharomycetales/genética , Regulação Fúngica da Expressão Gênica , Genes Fúngicos , IMP Desidrogenase/genética , IMP Desidrogenase/metabolismo , Elementos de Resposta , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomycetales/metabolismoRESUMO
The aim of this study was to select S. cerevisiae strains able to exert probiotic and antimycotoxin effects plus antibiotics resistance properties for use in animal production. S. cerevisiae LL74 and S. cerevisiae LL83 were isolated from bakery by-products intended for use in animal feed and examined for phenotypic characteristics and nutritional profile. Resistance to antibiotic, tolerance to gastrointestinal conditions, autoaggregation and coaggregation assay, antagonism to animal pathogens and aflatoxin B1 binding were studied. S. cerevisiae LL74 and S. cerevisiae LL83 showed resistance to all the antibiotics assayed (ampicillin, streptomycin, neomycin, norfloxacin, penicillin G, sulfonamide and trimethoprim). The analysis showed that exposure time to acid pH had a significant impact onto the viable cell counts onto both yeast strains. Presence of bile 0.5% increased significantly the growth of the both yeast strains. Moreover, they were able to tolerate the simulated gastrointestinal conditions assayed. In general, the coaggregation was positive whereas the autoaggregation capacity was not observed. Both strains were able to adsorb AFB1. In conclusion, selected S. cerevisiae LL74 and S. cerevisiae LL83 have potential application to be used as a biological method in animal feed as antibiotic therapy replacement in, reducing the adverse effects of AFB1 and giving probiotic properties.
Assuntos
Ração Animal/análise , Antibacterianos/farmacologia , Micotoxinas/farmacologia , Probióticos/análise , Saccharomyces cerevisiae/efeitos dos fármacos , Resíduos/análise , Animais , Farmacorresistência Fúngica , Saccharomyces cerevisiae/fisiologiaRESUMO
Objetivou-se avaliar o processo de adaptação de idosos que buscam, voluntariamente, residir em Instituição de Longa Permanência para Idosos (ILPI), na cidade de Fortaleza-CE, com base no modelo teórico de Roy. Pesquisa descritiva, realizada em uma IPLI com treze idosos residentes. A coleta de dados foi por meio de entrevista, nos meses de outubro e dezembro de 2011. Os dados foram tratados pela análise de conteúdo temática. Emergiram as seguintes temáticas: Eu Físico, subdividido em sensação corporal e imagem corporal; e Eu Pessoal, subdividido em auto coerência, auto ideal e ser moral-ético-espiritual. Assim, a opção de morar em ILPI não mudou efetivamente a vida dos idosos. Estes conseguiram adaptação ao local e convivem bem com os estímulos internos e externos.
This study aimed to evaluate the adaptation of elderly individuals voluntarily reside in Institution for the Aged (LTCF) in the city of Fortaleza-CE, based on the theoretical model of Roy. Descriptive study, in a IPLI involving thirteen elderly residents. Data collect was through interviews in the months of October and December 2011 and organized by thematic content analysis. The following themes has emerged: I Physical subdivided into body sensation and body image; Staff and I, subdivided into self-consistency and auto ideal be moral-ethical-spiritual. Thus, the option to live in ILPI not effectively changed the lives of elderly people. They managed to adapt to the local and coexist well with internal and external stimuli.
Este estudio tuvo como objetivo evaluar la adaptación de las personas mayores que residen voluntariamente en la Institución para la tercera edad (LTCF) en la ciudad de Fortaleza-CE, basado en el modelo teórico de Roy. Estudio descriptivo, en un IPLI con trece ancianos residentes. Los datos fueran recogidos a través de entrevistas en los meses de octubre y diciembre de 2011 y organizados mediante análisis de contenido temático. Emergieron los siguientes temas: subdivide I Física en la imagen corporal y sensación de cuerpo; El personal y yo, subdividen en auto-consistencia y auto ideal ser moral-ético-espiritual. Por lo tanto, la opción de vivir en ILPI no cambió de manera efectiva la vida de los ancianos. Se las arreglaron para adaptarse a lo local y convivir bien con los estímulos internos y externos.
Assuntos
Animais , Masculino , Coelhos , Tronco Encefálico/efeitos dos fármacos , Indenos/farmacologia , Micotoxinas/farmacologia , Tronco Encefálico/fisiologia , Diazepam/farmacologia , Estimulação Elétrica , Neurônios Motores/efeitos dos fármacos , Formação Reticular/efeitos dos fármacosRESUMO
Six single-flow continuous cultures were used to study the effects of the mycotoxins patulin (PAT) and zearalenone (ZEN) alone or in combination on rumen microbial fermentation. In each of the four 7-d periods, the fermenters were supplemented in a 2 × 3 factorial arrangement with two levels of PAT (0 and 20 mg/l) and three levels of ZEN (0, 5 and 10 mg/l). The treatments did not affect the apparent and true digestibility of organic matter. PAT alone decreased the digestibility of neutral detergent fibre (NDF) and acid detergent fibre (ADF) (p < 0.01), but in the presence of 5 or 10 mg/l of ZEN, there were no effects of PAT. In contrast, the digestibility of NDF and ADF was decreased at 10 mg/l of ZEN in the absence of PAT (p < 0.05). The pH of the fermenters increased after 2 and 3 d of PAT treatment (p < 0.01). PAT decreased the concentration of total volatile acids (VFA), the molar proportion of acetate and the acetate:proportionate ratio (p < 0.01). The molar concentrations of other VFA were unchanged. Ammonia N (NH3-N) flow increased (p < 0.05) and there was a tendency to a higher NH3-N concentration (p < 0.1) in fermenters with PAT. Total N, non-ammonia N and bacterial N as well as efficiency of microbial protein synthesis and efficiency of N utilisation were not affected by treatments. PAT was nearly completely degraded during incubation. The mean recovery of ZEN, α-zearalenol and ß-zearalenol expressed as a proportion of administered ZEN was less than 50% in effluents from fermenters receiving only ZEN and ZEN plus PAT, respectively. With exception of fibre digestion, the co-administration of PAT and ZEN did not elicit interaction effects on most measured parameters of rumen metabolism.
Assuntos
Bactérias/efeitos dos fármacos , Fermentação/efeitos dos fármacos , Fusarium/química , Micotoxinas/farmacologia , Patulina/farmacologia , Penicillium/química , Zearalenona/farmacologia , Animais , Reatores Biológicos , Bovinos , Feminino , Rúmen/metabolismo , Rúmen/microbiologia , Zeranol/análogos & derivados , Zeranol/farmacologiaRESUMO
Bothrops mattogrossensis snake is widely distributed throughout eastern South America and is responsible for snakebites in this region. This paper reports the purification and biochemical characterization of three new phospholipases A2 (PLA2s), one of which is presumably an enzymatically active Asp49 and two are very likely enzymatically inactive Lys49 PLA2 homologues. The purification was obtained after two chromatographic steps on ion exchange and reverse phase column. The 2D SDS-PAGE analysis revealed that the proteins have pI values around 10, are each made of a single chain, and have molecular masses near 13 kDa, which was confirmed by MALDI-TOF mass spectrometry. The N-terminal similarity analysis of the sequences showed that the proteins are highly homologous with other Lys49 and Asp49 PLA2s from Bothrops species. The PLA2s isolated were named BmatTX-I (Lys49 PLA2-like), BmatTX-II (Lys49 PLA2-like), and BmatTX-III (Asp49 PLA2). The PLA2s induced cytokine release from mouse neutrophils and showed cytotoxicity towards JURKAT (leukemia T) and SK-BR-3 (breast adenocarcinoma) cell lines and promastigote forms of Leishmania amazonensis. The structural and functional elucidation of snake venoms components may contribute to a better understanding of the mechanism of action of these proteins during envenomation and their potential pharmacological and therapeutic applications.
Assuntos
Bothrops/metabolismo , Leishmania/efeitos dos fármacos , Micotoxinas/química , Micotoxinas/farmacologia , Neoplasias Experimentais/tratamento farmacológico , Venenos de Serpentes/química , Venenos de Serpentes/farmacologia , Animais , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Masculino , Camundongos , Micotoxinas/isolamento & purificação , Neoplasias Experimentais/patologia , Venenos de Serpentes/isolamento & purificação , Taxa de Sobrevida , Resultado do TratamentoRESUMO
UNLABELLED: Cerulenin is a fungal toxin that inhibits both eukaryotic and prokaryotic ketoacyl-acyl carrier protein synthases or condensing enzymes. It has been used experimentally to treat cancer and obesity, and is a potent inhibitor of bacterial growth. Understanding the molecular mechanisms of resistance to cerulenin and similar compounds is thus highly relevant for human health. We have previously described a Bacillus subtilis cerulenin-resistant strain, expressing a point-mutated condensing enzyme FabF (FabF[I108F]) (i.e. FabF with isoleucine 108 substituted by phenylalanine). We now report the crystal structures of wild-type FabF from B. subtilis, both alone and in complex with cerulenin, as well as of the FabF[I108F] mutant protein. The three-dimensional structure of FabF[I108F] constitutes the first atomic model of a condensing enzyme that remains active in the presence of the inhibitor. Soaking the mycotoxin into preformed wild-type FabF crystals allowed for noncovalent binding into its specific pocket within the FabF core. Interestingly, only co-crystallization experiments allowed us to trap the covalent complex. Our structure shows that the covalent bond between Cys163 and cerulenin, in contrast to that previously proposed, implicates carbon C3 of the inhibitor. The similarities between Escherichia coli and B. subtilis FabF structures did not explain the reported inability of ecFabF[I108F] (i.e. FabF from Escherichia coli with isoleucine 108 substituted by phenylalanine) to elongate medium and long-chain acyl-ACPs. We now demonstrate that the E. coli modified enzyme efficiently catalyzes the synthesis of medium and long-chain ketoacyl-ACPs. We also characterized another cerulenin-insensitive form of FabF, conferring a different phenotype in B. subtilis. The structural, biochemical and physiological data presented, shed light on the mechanisms of FabF catalysis and resistance to cerulenin. DATABASE: Crystallographic data (including atomic coordinates and structure factors) have been deposited in the Protein Data Bank under accession codes 4LS5, 4LS6, 4LS7 and 4LS8.
Assuntos
Bacillus subtilis/efeitos dos fármacos , Bacillus subtilis/enzimologia , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Cerulenina/farmacologia , Ácido Graxo Sintase Tipo II/química , Ácido Graxo Sintase Tipo II/metabolismo , Acetiltransferases/química , Acetiltransferases/genética , Acetiltransferases/metabolismo , Bacillus subtilis/genética , Proteínas de Bactérias/genética , Domínio Catalítico/genética , Cristalografia por Raios X , Farmacorresistência Bacteriana/genética , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Ácido Graxo Sintase Tipo II/genética , Inibidores da Síntese de Ácidos Graxos/farmacologia , Genes Bacterianos , Humanos , Modelos Moleculares , Micotoxinas/farmacologia , Mutação Puntual , Estrutura Quaternária de Proteína , Eletricidade EstáticaRESUMO
Alternariol and monomethylalternariol are natural phytotoxins produced by some fungal strains, such as Nimbya and Alternaria. These substances confer virulence to phytopathogens, yet no information is available concerning their mode of action. Here we show that in the micromolar range alternariol 9-methyl ether is able to inhibit the electron transport chain (IC50 = 29.1 ± 6.5 µM) in isolated spinach chloroplasts. Since its effectiveness is limited by poor solubility in water, several alternariol analogues were synthesized using different aromatic aldehydes. The synthesized 6H-benzo[c]cromen-6-ones, 5H-chromene[4,3-b]pyridin-5-one, and 5H-chromene[4,3-c]pyridin-5-one also showed inhibitory properties, and three 6H-benzo[c]cromen-6-ones were more effective (IC50 = 12.8-22.8 µM) than the lead compound. Their addition to the culture medium of a cyanobacterial model strain was found to inhibit algal growth, with a relative effectiveness that was consistent with their activity in vitro. In contrast, the growth of a nonphotosynthetic plant cell culture was poorly affected. These compounds may represent a novel lead for the development of new active principles targeting photosynthesis.
Assuntos
Cromonas/farmacologia , Lactonas/farmacologia , Fotossíntese/efeitos dos fármacos , Piridonas/farmacologia , Alternaria/química , Cloroplastos/efeitos dos fármacos , Cloroplastos/metabolismo , Cromonas/síntese química , Cromonas/química , Transporte de Elétrons/efeitos dos fármacos , Lactonas/análise , Lactonas/síntese química , Lactonas/química , Estrutura Molecular , Micotoxinas/farmacologia , Oxirredução , Piridonas/síntese química , Piridonas/química , Spinacia oleracea/citologia , Spinacia oleracea/metabolismoRESUMO
An enzyme assay for bacterial undecaprenyl pyrophosphate (UPP) synthase was performed to screen microbial culture broths for inhibitors of UPP synthase. During the course of this screening program, an EtOH extract of a rice culture of Penicillium brasilianum FKI-3368 was found to inhibit UPP synthase activity. From activity-guided purification, a new compound-designated spirohexaline was isolated together with the structurally related and known viridicatumtoxin by ethyl acetate extraction silica gel and octadecylsilane column chromatographies and high-performance liquid chromatography. The structure of spirohexaline was elucidated by spectroscopic analysis, including NMR. Spirohexaline and viridicatumtoxin have a common hexacycline structure produced by fusion of a tetracycline-type ring with a spiro-type ring. They inhibited UPP synthase activity with IC50 values of 9.0 and 4.0 µM, respectively.