RESUMO
The effects of shrimp farm effluents on bacterial communities in mangroves have been infrequently reported. Classic and molecular biology methods were used to survey bacterial communities from four mangroves systems. Water temperature, salinity, pH, total heterotrophic bacteria and maximum probable numbers of Vibrio spp. were investigated. Genetic profiles of bacterial communities were also characterized by polymerase chain reaction (PCR) amplification of eubacterial and Vibrio 16S rDNA using denaturing gradient gel electrophoresis (DGGE). Highest heterotrophic counts were registered in the mangrove not directly polluted by shrimp farming. The Enterobacteriaceae and Chryseomonas luteola dominated the heterotrophic isolates. Vibrio spp. pathogenic to humans and shrimps were identified. Eubacterial genetic profiles suggest a shared community structure independent of mangrove system. Vibrio genetic profiles were mangrove specific. Neither microbial counts nor genetic profiling revealed a significant decrease in species richness associated with shrimp farm effluent. The complex nature of mangrove ecosystems and their microbial communities is discussed.
Assuntos
Fenômenos Fisiológicos Bacterianos , Biodiversidade , Monitoramento Ambiental , Água do Mar/microbiologia , Aquicultura , Bactérias/genética , Bactérias/isolamento & purificação , Brasil , Contagem de Colônia Microbiana/métodos , Filogenia , RNA Ribossômico 16S/genética , Rhizophoraceae , Água do Mar/química , Vibrio/genética , Vibrio/isolamento & purificaçãoRESUMO
Newly designed group-specific PCR primers for denaturing gradient gel electrophoresis (DGGE) were used to investigate foaming mycolata from a bioreactor treating an industrial saline waste-water. Genetic profiles on DGGE gels were different with NaCl at 1.65 and 8.24 g l(-1), demonstrating that mycolata community was affected by salinity. A semi-nested PCR strategy resulted in more bands in community genetic profiles than direct amplification. DNA sequencing of bands confirmed the efficacy of the novel primers with sequences recovered being most similar to foam producing mycolata. The new group-specific primers/DGGE approach is a new step toward a more complete understanding of functionally important groups of bacteria involved in biological treatment of waste-water.
Assuntos
Actinobacteria/genética , Primers do DNA/genética , Resíduos Industriais/análise , Reação em Cadeia da Polimerase/métodos , Gerenciamento de Resíduos/métodos , Actinobacteria/isolamento & purificação , Biodegradação Ambiental , Ecossistema , Eletroforese em Gel de Poliacrilamida , Ácidos Micólicos/química , RNA Ribossômico 16S/classificação , Análise de Sequência de DNA/métodos , Purificação da Água/métodosRESUMO
AIMS: Characterization of yeast populations and genetic polymorphism of Saccharomyces cerevisiae strains collected during the short fermentative cycles from the spontaneous fermentations during the artisanal cachaça production. METHODS AND RESULTS: The prevalent S. cerevisiae strains were analysed by PFG and RAPD-PCR using primers EI1 and M13. The molecular analysis have showed a high degree of genetic polymorphism among the strains within a 24 h fermentative cycle. CONCLUSION: The genetic diversity observed in the S. cerevisiae strains may be occurring due to the existence of a large number of individual genotypes within the species. The unique characteristics of the cachaça fermentation process probably allows for a faster detection of molecular polymorphisms of yeast strains than other types of fermentations. SIGNIFICANCE AND IMPACT OF THE STUDY: Spontaneous fermentations to produce cachaça, due to their characteristics, are an excellent model for the study of molecular diversity of S. cerevisiae strains during the production of fermented beverages.
Assuntos
Bebidas Alcoólicas/microbiologia , Poaceae/microbiologia , Polimorfismo Genético/genética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/isolamento & purificação , Brasil , Fermentação , Genótipo , Técnicas de Tipagem Micológica , Filogenia , Técnica de Amplificação ao Acaso de DNA Polimórfico , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Fatores de Tempo , Leveduras/genética , Leveduras/crescimento & desenvolvimento , Leveduras/isolamento & purificação , Leveduras/metabolismoRESUMO
Yeast communities and genetic polymorphism of prevalent Saccharomyces cerevisiae strains isolated from the spontaneous fermentation of the sugarcane juice during the production of aguardente in three distilleries in the state of Minas Gerais, Brazil, were studied. S. cerevisiae was the prevalent species during the process of aguardente production, but Schizosaccharomyces pombe was predominant in old fermentations in one distillery. Transient yeast species were found in a variable number, probably due to the daily addition of sugarcane juice, and they were different for each of the three distilleries studied. PFGE and PCR analysis of the predominant strains of S. cerevisiae isolated from the fermented must showed a high degree of genetic polymorphism among the three distilleries. A high molecular variability of S. cerevisae strains was also observed among strains isolated from the same vat at different fermentation ages. Our results showed that there was a succession of geneticly different strains of S. cerevisae during the process of aguardente production.
Assuntos
Bebidas Alcoólicas , Polimorfismo Genético , Saccharomyces cerevisiae/genética , Leveduras/crescimento & desenvolvimento , Brasil , Fermentação , Poaceae , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/isolamento & purificação , Leveduras/genética , Leveduras/isolamento & purificaçãoRESUMO
Yeast communities associated with sugarcane leaves, stems and rhizosphere during different phases of plant development were studied near Campos, in Rio de Janeiro, Brazil. Atmospheric temperature, soil granulometry and pH, and sugar cane juice degree Brix and pH were determined. Yeast communities associated with sugarcane were obtained after cellular extraction by shaking, blending and shaking plus sonication, and cultured on Yeast Nitrogen Base Agar plus glucose (0.5%) and Yeast Extract-Malt Extract Agar. No significant differences in yeast counts were found among the cellular extraction treatments and culture media. 230 yeast cultures were identified according to standard methods, and distinct yeast communities were found for each substrate studied. The prevalent species isolated from sugarcane were Cryptococcus laurentii, Cryptococcus albidus, Rhodotorula mucilaginosa and Debaryomyces hansenii.
Assuntos
Plantas/microbiologia , Leveduras/classificação , BrasilRESUMO
The presence of killer and proteolytic yeasts was studied among 944 isolates representing 105 species from tropical yeast communities. We found 13 killer toxin producing species, with Pichia kluyveri being the most frequent. Other killer yeast isolates were Candida apis, Candida bombicola, Candida fructus, Candida krusei, Candida sorbosa, Hanseniaspora uvarum, Issatchenkia occidentalis, Kloeckera apis, Kluyveromyces marxianus, Pichia membranaefaciens, Pichia ohmeri-like, and Sporobolomyces roseus. The communities from which killer yeasts were isolated had strains sensitive to them, and there were interspecific and intraspecific differences in the spectra of their killer activities. Pichia kluyveri had the broadest spectra of activity against sensitive isolates, and it apparently produced different toxins. The coexistence of sensitive and killer yeasts using the same substrate suggests that there is spatial separation in microhabitats or temporal separation in different stages of successions. Basidiomycetous yeasts were more frequently proteolytic than ascomycetous yeasts. Extracellular proteases could be important for the yeasts to have access to more nitrogen nutrients and obtain a better balance with available carbon sources.
Assuntos
Endopeptidases/análise , Micotoxinas/análise , Leveduras/classificação , Endopeptidases/metabolismo , Micotoxinas/metabolismo , Leveduras/metabolismoRESUMO
Pseudomonas strains were isolated from the rhizosphere of maize grown in yellow-red latosol from Rio de Janeiro, Brazil, to serve as a delivery system for heterologous genes and for risk assessment studies in tropical soils. Selected strains were modified by insertion of the cryIVB gene from Bacillus thuringiensis and tested for pathogenicity gene expression against larvae of a susceptible model species, Anopheles aquasalis. Modified strains Br8 and Br12 showed similar survival performance to their parental strains, and presented a viable density of 10(7) c.f.u./g dry soil 30 days after release. A strain of P. fluorescens (Br12) that presented positive results for gene expression and the best survival performance, was selected for risk assessment studies in soil microcosms.
RESUMO
The succession of yeasts colonizing the fallen ripe amapa fruit, from Parahancornia amapa, was examined. The occupation of the substrate depended on both the competitive interactions of yeast species, such as the production of killer toxins, and the selective dispersion by the drosophilid guild of the amapa fruit. The yeast community associated with this Amazon fruit differed from those isolated from other fruits in the same forest. The physiological profile of these yeasts was mostly restricted to the assimilation of a few simple carbon sources, mainly L-sorbose, D-glycerol, DL-lactate, cellobiose, and salicin. Common fruit-associated yeasts of the genera Kloeckera and Hanseniaspora, Candida guilliermondii, and Candida krusei colonized fruits during the first three days after the fruit fell. These yeasts were dispersed and served as food for the invader Drosophila malerkotliana. The resident flies of the Drosophila willistoni group fed selectively on patches of yeasts colonizing fruits 3 to 10 days after the fruit fell. The killer toxin-producing yeasts Pichia kluyveri var. kluyveri and Candida fructus were probably involved in the exclusion of some species during the intermediate stages of fruit deterioration. An increase in pH, inhibiting toxin activity and the depletion of simple sugars, may have promoted an increase in yeast diversity in the later stages of decomposition. The yeast succession provided a patchy environment for the drosophilids sharing this ephemeral substrate.
Assuntos
Drosophila/microbiologia , Microbiologia de Alimentos , Frutas/microbiologia , Fungos/isolamento & purificação , Animais , Fungos/crescimento & desenvolvimentoRESUMO
The ascomycetous yeast communities associated with 3 bivalve mollusk, and 4 crab species were studied in the mangrove at Coroa Grande on Sepetiba Bay in Rio de Janeiro, Brazil. These were made up mostly of diverse but sparse and apparently allochtonous yeast populations. The striking exception was a prevalent population of the species Kluyveromyces aestuarii, which predominated the yeast communities of 2 detritus feeding crabs, Sesarma rectum and Uca spp., and the shipworm Neoteredo reynei. However, K. aestuarii was absent from the omnivorous crabs Aratus pisonii and Goniopsis cruentata, and the clam Anomalocardia brasiliana, and was rare in the clam Tagelus plebeius from mostly submerged more sandy sediments. Pichia membranaefaciens, Candida valida-like, Candida krusei, Candida sorbosa, Candida colliculosa-like, Candida famata-like, Kloeckera spp., Candida guilliermondii, Candida albicans, Candida silvae, Geotrichum spp., Rhodotorula spp., Cryptococcus spp., and the methylotrophic yeast Candida boidinii were frequently isolated. The 322 ascomycetous yeast cultures representing 252 isolates from crabs and mollusks were classified as 40 species that fit standard descriptions, and 44 putative new species. The ascomycetous yeast communities of the mangrove ecosystem include many new biotypes that require better taxonomic definition.
Assuntos
Ascomicetos/classificação , Braquiúros/microbiologia , Moluscos/microbiologia , Leveduras/classificação , Animais , Ascomicetos/isolamento & purificação , Brasil , Candida/classificação , Candida/isolamento & purificação , Ecossistema , Técnicas de Tipagem Micológica , Poluição da Água , Leveduras/isolamento & purificaçãoRESUMO
Genetic and karyotypic studies of some Saccharomyces sensu stricto yeasts from Brazil revealed a genetically isolated population which apparently represents a new sibling species of S. cerevisiae.