ABSTRACT
The aim of this study was to investigate the mechanisms by which yeasts (Saccharomyces cerevisiae) control the toxic effects of aflatoxins, which are not yet fully understood. Radiolabeled aflatoxin B1 (AFB13H) was administered by gavage to Wistar rats fed with aflatoxin (AflDiet) and aflatoxin supplemented with active dehydrated yeast Y904 (AflDiet + Yeast). The distribution of AFB13H and its metabolites were analyzed at 24, 48 and 72 h by tracking back of the radioactivity. No significant differences were observed between the AflDiet and AflDiet + Yeast groups in terms of the distribution of labeled aflatoxin. At 72 h, for the AflDiet group the radiolabeled aflatoxin was distributed as following: feces (79.5%), carcass (10.5%), urine (1.7%), and intestine (7.4%); in the AflDiet + Yeast the following distribution was observed: feces (76%), carcass (15%), urine (2.9%), and intestine (4.9%). These values were below 1% in other organs. These findings indicate that even after 72 h considerable amounts of aflatoxins remains in the intestines, which may play a significant role in the distribution and metabolism of aflatoxins and its metabolites over time. The presence of yeast may not significantly affect this process. Furthermore, histopathological examination of hepatic tissues showed that the presence of active yeast reduced the severity of liver damage caused by aflatoxins, indicating that yeasts control aflatoxin damage through biochemical mechanisms. These findings contribute to a better understanding of the mechanisms underlying the protective effects of yeasts against aflatoxin toxicity.
Subject(s)
Aflatoxins , Saccharomyces cerevisiae , Rats , Animals , Rats, Wistar , Aflatoxins/toxicity , Dietary Supplements , FecesABSTRACT
Pleurotus ostreatus is a widely cultivated white-rot fungus. Owing to its considerable enzymatic versatility P. ostreatus has become the focus of increasing attention for its possible utility in biobleaching and bioremediation applications. Interactions between microorganisms can be an important factor in those processes. In this study, we describe the presence of a bacterial species associated with P. ostreatus strain G2. This bacterial species grew slowly (approximately 30 days) in the liquid and semi-solid media tested. When P. ostreatus was inoculated in solid media containing Tween 80 or Tween 20, bacterial microcolonies were detected proximal to the fungal colonies, and the relevant bacterium was identified via the analysis of a partial 16S rDNA sequence; it was determined to belong to the Burkholderia cepacia complex, but was not closely related to other fungus-isolated Burkholderiaceae. New specific primers were designed, and confirmed the presence of in vitro P. ostreatus cultures. This is the first time that a bacterial species belonging to the B. cepacia complex has been found associated with P. ostreatus.
Subject(s)
Burkholderia cepacia complex/growth & development , Burkholderia cepacia complex/isolation & purification , Pleurotus/growth & development , Burkholderia cepacia complex/classification , Burkholderia cepacia complex/genetics , Coculture Techniques , Culture Media , DNA, Bacterial/analysis , DNA, Bacterial/isolation & purification , DNA, Ribosomal/analysis , Molecular Sequence Data , Phylogeny , Polymerase Chain Reaction , RNA, Ribosomal, 16S/geneticsABSTRACT
O comportamento da viabilidade celular de leveduras é essencial quando se almeja utilizá-la como um probiótico e o veículo que assegure esta propriedade até o momento do consumo é particularmente. Sobre grãos de milho, contendo 16 ou 20% de umidade, foram aplicadas leveduras desidratadas vivas, nas concentrações de 1 e de 2%. A viabilidade celular foi avaliada nos períodos de 0, 15, 30, 90 e 110 dias de armazenamento. A viabilidade celular nas leveduras não diferiu estatisticamente entre os tratamentos aos 30 dias em armazenamento, com a viabilidade média de 89,10%. A viabilidade média encontrada aos 90 dias de 72,20% foi menor do que aquelas nos três primeiros períodos de armazenamento. Após 110 dias de armazenamento foi de 61,14%. Conclue-se que leveduras apresentam viabilidade celular até 110 dias em armazenamento sobre milho e que estes podem ser utilizados como um veículo para a aplicação da levedura como um probiótico.
ABSTRACT
O objetivo desta revisão de literatura foi abordar as condições favoráveis ao desenvolvimento de fungos toxigênicos que podem produzir micotoxinas. Os aspectos tratados incluíram temperatura e umidade, agentes competidores e atmosfera de crescimento. Também foram abordados os meios de cultura para identificação de fungos micootoxigênicos. Concluiu-se que o conhecimento dos fatores ligados à produção de micotoxinas possibilita a adoção de medidas para reduzir a presença de toxinas e melhorar o aproveitamento dos alimentos.
Subject(s)
Culture Media , Food Industry , Food Microbiology , Fungi , Mycotoxins , Biological FactorsABSTRACT
O uso de cobre na confecçäo de destiladores e acessórios para a indústria de bebidas destiladas favorece a qualidade sensorial da bebida. O presente trabalho teve por escopo correlacionar o teor de cobre na aguardente de cana com o grau alcoólico e a acidez do destilado. Constatou-se que os teores de cobre durante a destilaçäo acompanham os teores de acidez do destilado, encontrando-se ambos em maior concentraçäo na fraçäo cauda. Cortando-se a destilaçäo do produto com alto grau alcoólico os teores de acidez e de cobre säo reduzidos
