RESUMO
Actinobacteria occur in many environments and have the capacity to produce secondary metabolites with antibiotic potential. Identification and taxonomy of actinobacteria that produce antimicrobial substances is essential for the screening of new compounds, and sequencing of the 16S region of ribosomal DNA (rDNA), which is conserved and present in all bacteria, is an important method of identification. Melanized fungi are free-living organisms, which can also be pathogens of clinical importance. This work aimed to evaluate growth inhibition of melanized fungi by actinobacteria and to identify the latter to the species level. In this study, antimicrobial activity of 13 actinobacterial isolates from the genus Streptomyces was evaluated against seven melanized fungi of the genera Exophiala, Cladosporium, and Rhinocladiella. In all tests, all actinobacterial isolates showed inhibitory activity against all isolates of melanized fungi, and only one actinobacterial isolate had less efficient inhibitory activity. The 16S rDNA region of five previously unidentified actinobacterial isolates from Ilha do Mel, Paraná, Brazil, was sequenced; four of the isolates were identified as Streptomyces globisporus subsp. globisporus, and one isolate was identified as Streptomyces aureus. This work highlights the potential of actinobacteria with antifungal activity and their role in the pursuit of novel antimicrobial substances.(AU)
Assuntos
Antifúngicos , Exophiala , Cladosporium , Actinobacteria/classificação , Actinobacteria/genética , Análise de Sequência de RNA , Controle Biológico de Vetores , AntibacterianosRESUMO
Abstract Actinobacteria occur in many environments and have the capacity to produce secondary metabolites with antibiotic potential. Identification and taxonomy of actinobacteria that produce antimicrobial substances is essential for the screening of new compounds, and sequencing of the 16S region of ribosomal DNA (rDNA), which is conserved and present in all bacteria, is an important method of identification. Melanized fungi are free-living organisms, which can also be pathogens of clinical importance. This work aimed to evaluate growth inhibition of melanized fungi by actinobacteria and to identify the latter to the species level. In this study, antimicrobial activity of 13 actinobacterial isolates from the genus Streptomyces was evaluated against seven melanized fungi of the genera Exophiala, Cladosporium, and Rhinocladiella. In all tests, all actinobacterial isolates showed inhibitory activity against all isolates of melanized fungi, and only one actinobacterial isolate had less efficient inhibitory activity. The 16S rDNA region of five previously unidentified actinobacterial isolates from Ilha do Mel, Paraná, Brazil, was sequenced; four of the isolates were identified as Streptomyces globisporus subsp. globisporus, and one isolate was identified as Streptomyces aureus. This work highlights the potential of actinobacteria with antifungal activity and their role in the pursuit of novel antimicrobial substances.
Assuntos
Actinobacteria/fisiologia , Fungos/fisiologia , Antibiose , Filogenia , Streptomyces/classificação , Streptomyces/genética , Brasil , RNA Ribossômico 16S/genética , Actinobacteria/isolamento & purificação , Actinobacteria/classificação , Actinobacteria/genéticaRESUMO
Actinobacteria occur in many environments and have the capacity to produce secondary metabolites with antibiotic potential. Identification and taxonomy of actinobacteria that produce antimicrobial substances is essential for the screening of new compounds, and sequencing of the 16S region of ribosomal DNA (rDNA), which is conserved and present in all bacteria, is an important method of identification. Melanized fungi are free-living organisms, which can also be pathogens of clinical importance. This work aimed to evaluate growth inhibition of melanized fungi by actinobacteria and to identify the latter to the species level. In this study, antimicrobial activity of 13 actinobacterial isolates from the genus Streptomyces was evaluated against seven melanized fungi of the genera Exophiala, Cladosporium, and Rhinocladiella. In all tests, all actinobacterial isolates showed inhibitory activity against all isolates of melanized fungi, and only one actinobacterial isolate had less efficient inhibitory activity. The 16S rDNA region of five previously unidentified actinobacterial isolates from Ilha do Mel, Paraná, Brazil, was sequenced; four of the isolates were identified as Streptomyces globisporus subsp. globisporus, and one isolate was identified as Streptomyces aureus. This work highlights the potential of actinobacteria with antifungal activity and their role in the pursuit of novel antimicrobial substances.
Assuntos
Actinobacteria/fisiologia , Antibiose , Fungos/fisiologia , Actinobacteria/classificação , Actinobacteria/genética , Actinobacteria/isolamento & purificação , Brasil , Filogenia , RNA Ribossômico 16S/genética , Streptomyces/classificação , Streptomyces/genéticaRESUMO
Frutos consumidos in natura apresentam potencial de risco à saúde do consumidor pela transmissão de doenças. O objetivo do trabalho foi identificar os potenciais patógenos presentes em diferentes etapas de produção em duas propriedades produtoras de morango, em São José dos Pinhais, Paraná. Na I água de irrigação e nas mãos dos produtores foi observada a presença de Escherichia coli; em caixas de coleta apenas Staphylococcus aureus; nos frutos ausência destes micro-organismos. Bolores e leveduras ocorreram em todas as amostras avaliadas. Os resultados obtidos em todas as etapas de cultivo de morangueiro indicam a necessidade urgente de treinamento dos produtores e o estabelecimento de normas de boas práticas visando a sanidade dos frutos ofertados à população. (AU)
Fruits consumed in natura present potential risk to consumers' health through diseases transmission. This work aimed to identify potential pathogens found in the different steps of strawberry production, in two areas of São José dos Pinhais, Paraná. The presence of Escherichia coli was found in both irrigation water and producer's hands; Staphylococcus aureus was found only in collection boxes; there was no indication of these microorganisms presence in the fruit. Molds and yeasts were present in all samples. The results indicate the need to train strawberry producers and to establish norms of good practices aiming the health of the fruits offered to the population.(AU)
Assuntos
Humanos , Fragaria/microbiologia , Alimentos , Microbiologia de Alimentos , Coliformes , Staphylococcus aureus/isolamento & purificação , BrasilRESUMO
Paecilomyces lilacinus has potential for pests control. We aimed to analyze mycelial growth and spore production in P. lilacinus strains in several agro-industrial residues and commercial media. This study suggests alternative nutrient sources for fungi production and that the biotechnological potential of agro-industrial refuses could be employed in byproducts development.
Paecilomyces lilacinus apresenta potencial para controle de pragas. O objetivo deste trabalho foi analisar o crescimento micelial e a produção de esporos de linhagens de P. lilacinus em resíduos agro-industriais e meios comerciais. Este estudo sugere fontes alternativas para produção de fungos com potencial biotecnológico para desenvolvimento de bioprodutos.
Assuntos
Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/isolamento & purificação , Micélio/crescimento & desenvolvimento , Controle Biológico de Vetores , Resíduos de Praguicidas , Biotecnologia , Métodos , Linhagem , MétodosRESUMO
Paecilomyces lilacinus has potential for pests control. We aimed to analyze mycelial growth and spore production in P. lilacinus strains in several agro-industrial residues and commercial media. This study suggests alternative nutrient sources for fungi production and that the biotechnological potential of agro-industrial refuses could be employed in byproducts development.
RESUMO
Beauveria bassiana strains from different hosts and geographic origins were assayed for the presence of double-stranded RNA (dsRNA). Two of them (15.4%) showed extra bands, with approximately 4.0-3.5 kb and 2-0.7 kb, respectively, after electrophoretic separation of undigested nucleic acids. Virus-like particles were approximately 28-30 nm diam. The dsRNA was maintained after conidiogenesis (vertical transmission) and was transmitted horizontally by hyphal anastomosis. Strains purged of dsRNA obtained after cycloheximide treatment showed increased conidial production when compared with strains carrying dsRNA particles. Bioassays demonstrated hypovirulence associated with dsRNA. The mean mortality against the insect Euschistus heros was reduced in strains containing dsRNA when compared with the isogenic dsRNA-free ones.
Assuntos
Beauveria/patogenicidade , Beauveria/virologia , Infecções por Vírus de RNA/virologia , Vírus de RNA/isolamento & purificação , RNA de Cadeia Dupla/isolamento & purificação , Animais , Beauveria/ultraestrutura , Desoxirribonuclease I/metabolismo , Insetos , Microscopia Eletrônica de Transmissão , Vírus de RNA/genética , Vírus de RNA/metabolismo , Vírus de RNA/ultraestrutura , RNA de Cadeia Dupla/genética , RNA de Cadeia Dupla/metabolismo , RNA de Cadeia Dupla/ultraestrutura , RNA Viral/química , RNA Viral/genética , Técnica de Amplificação ao Acaso de DNA Polimórfico , Ribonuclease Pancreático/metabolismo , Endonucleases Específicas para DNA e RNA de Cadeia Simples/metabolismo , VirulênciaRESUMO
To understand the nature of recombination processes in Beauveria bassiana, double-auxotrophic complementary mutant strains were used to produce six heterokaryons by three different methods. Conidia from these heterokaryons were plated on selective media and stable haploid (but not diploid) recombinants were isolated. Single colony recombinants were recovered with both parental and non-parental random amplified polymorphic DNA (RAPD) profiles. These results suggest that a range of different recombination mechanisms may be occurring in B. bassiana.