ABSTRACT
ABSTRACT Anthropogenic activity, such as accidental oil spills, are typical sources of urban mangrove pollution that may affect mangrove bacterial communities as well as their mobile genetic elements. To evaluate remediation strategies, we followed over the time the effects of a petroleum hydrocarbon degrading consortium inoculated on mangrove tree Avicennia schaueriana against artificial petroleum contamination in a phytoremediation greenhouse experiment. Interestingly, despite plant protection due to the inoculation, denaturing gradient gel electrophoresis of the bacterial 16S rRNA gene fragments amplified from the total community DNA indicated that the different treatments did not significantly affect the bacterial community composition. However, while the bacterial community was rather stable, pronounced shifts were observed in the abundance of bacteria carrying plasmids. A PCR-Southern blot hybridization analysis indicated an increase in the abundance of IncP-9 catabolic plasmids. Denaturing gradient gel electrophoresis of naphthalene dioxygenase (ndo) genes amplified from cDNA (RNA) indicated the dominance of a specific ndo gene in the inoculated petroleum amendment treatment. The petroleum hydrocarbon degrading consortium characterization indicated the prevalence of bacteria assigned to Pseudomonas spp., Comamonas spp. and Ochrobactrum spp. IncP-9 plasmids were detected for the first time in Comamonas sp. and Ochrobactrum spp., which is a novelty of this study.
Subject(s)
Bacteria/isolation & purification , Bacteria/metabolism , Avicennia/microbiology , Hydrocarbons/metabolism , Plasmids/genetics , Plasmids/metabolism , Soil Pollutants/analysis , Soil Pollutants/metabolism , Bacteria/classification , Bacteria/genetics , Biodegradation, Environmental , DNA, Bacterial/genetics , Petroleum/analysis , RNA, Ribosomal, 16S/genetics , Petroleum Pollution/analysis , Avicennia/metabolism , RhizosphereABSTRACT
Five strains of Rhodotorula mucilaginosa were tested for the ability to accumulate free and complexed silver ions by metabolism-dependent and -independent processes. The ability to take up Ag+ was observed in both live and dead biomass, whereas silver dicyanide [Ag (CN)2-] uptake was strictly glucose dependent. In contrast to Ag (CN)2-, glucose addition inhibited by 16 to 25(per cent) the Ag+ uptake rate of living UFMG - Y02, Y27, and Y35 cells, while strains CBS 316 and UFMG-Y01 showed an improved uptake rate of about 115(per cent) and 13(per cent), respectively. The Langmuir sorption model was used to evaluate the silver sorption capability of the R. mucilaginosa strains. The calculated qmax value suggested that R. mucilaginosa strains UFMG-Y27 had the highest loading capacity. The type strain CBS 316 had the lowest qmax but showed the highest affinity for silver ions. The results provided by the Fourier Transform Infra Red analysis (FTIR) suggest that C=O groups represent the main reactive site for silver uptake by the strain UFMG-Y27.
Subject(s)
Bioaccumulation , In Vitro Techniques , Ions , Metabolism , Rhodotorula , Silver , Language Tests , PedigreeABSTRACT
Yeasts had men counts of above 10 (6) CFU/gin the fecal pellets of small mammals from tropical forest fragments. Most of the 55 species isolated werefermentative ascomycetes, with the most frequent being Debaryomyces hansenii, Pichia membranifaciens and Issatchenkia orientalis, whereas Rhodotorula mucilaginosa was the most frequent yeast of basidiomycetous affinity
Subject(s)
Animals , Rodentia , Yeasts/isolation & purification , Feces , Marsupialia , Ascomycota/isolation & purification , Brazil , Environmental Microbiology , Pest Control, Biological/methodsABSTRACT
The response of a genetically modified Pseudomonas flurescens to nutrient starvation and starvation-induced stress cross-protection were investigated. Strain BR12 was starved for carbon, nitrogen, phosphorus and sulphur individually and for all nutrients in defined mineral media and exposed for 6 h to chemical (ethanol 20 percentage), oxidative (H2O220µM), osmotic (NaCl3M), cold shock (0 degree) and heat shock (47 degree C) stresses at different incubationtimes. Response to starvation and stress cross-protection development were evaluated by viable bacteria counts. There was a significant increase in resistance of late phase cultures grown in rich medium to stress, except for ethanol, in all starvation situations. Multiple nutrient starved cultures were more resistant to stress than individual nutrient starved ones. This strain inoculated in oligotrophic stream water microcosms also showed the starvation-induced stress protection mechanism but it presented a higher resistance to ethanol than cultures starved in mineral media. the acquisition of nonspecific resistance to stress can favour the persistance of Genetically Modified Microorganisms (GMMos) in apparently unfavourable.
Subject(s)
Stress, Physiological/etiology , Pseudomonas fluorescens/physiology , Genetic Engineering , Food Deprivation , Sulfur , Carbon , Phosphorus , NitrogenABSTRACT
Leveduras foram detectadas em leite em 50 de 158 doadores. As contagens de leveduras foram menores do que 10/ml em 90 por cento das amostras e acima de 1000/ml em somente 0.4 por cento. As espécies predominantes foram Candida parapsilosis, Candida guilhermondii, Candida famata, Candida sorbophila, Rhodotorula minuta, Candida albicans, Candida sphaerica, e Pichia ohmeri.