RESUMEN
In the present study, metagenomic technique and fosmid vectors were used to construct a library of clones for exploring the biotechnological potential of mangrove soils by isolation of functional genes encoding hydrolytic enzymes. The library was built with genomic DNA from the soil samples of mangrove sediments and the functional screening of 1824 clones (~64 Mbp) was performed to detect the hydrolytic activity specific for cellulases, amylases (at acidic, neutral and basic pH), lipases/esterases, proteases, and nitrilases. Significant numbers of clones, positive for the tested enzyme activities were obtained. Our results indicate the importance and biotechnological potential of mangrove soils especially when compared to those obtained using other soil metagenomic libraries.
Asunto(s)
Bacterias/enzimología , Proteínas Bacterianas/genética , Biblioteca de Genes , Vectores Genéticos/química , Metagenoma , Microbiología del Suelo , Humedales , Aminohidrolasas/genética , Amilasas/genética , Bacterias/genética , Proteínas Bacterianas/metabolismo , Celulasas/genética , Medios de Cultivo/química , Esterasas/genética , Consorcios Microbianos/genética , Péptido Hidrolasas/genética , Análisis de Secuencia de ADN , Suelo/químicaRESUMEN
Previous studies in dementia epidemiology have reported higher Alzheimer's disease rates in African-Americans when compared with White Americans. To determine whether genetically determined African ancestry is associated with neuropathological changes commonly associated with dementia, we analyzed a population-based brain bank in the highly admixed city of São Paulo, Brazil. African ancestry was estimated through the use of previously described ancestry-informative markers. Risk of presence of neuritic plaques, neurofibrillary tangles, small vessel disease, brain infarcts and Lewy bodies in subjects with significant African ancestry versus those without was determined. Results were adjusted for multiple environmental risk factors, demographic variables and apolipoprotein E genotype. African ancestry was inversely correlated with neuritic plaques (P=0.03). Subjects with significant African ancestry (n=112, 55.4%) showed lower prevalence of neuritic plaques in the univariate analysis (odds ratio (OR) 0.72, 95% confidence interval (CI) 0.55-0.95, P=0.01) and when adjusted for age, sex, APOE genotype and environmental risk factors (OR 0.43, 95% CI 0.21-0.89, P=0.02). There were no significant differences for the presence of other neuropathological alterations. We show for the first time, using genetically determined ancestry, that African ancestry may be highly protective of Alzheimer's disease neuropathology, functioning through either genetic variants or unknown environmental factors. Epidemiological studies correlating African-American race/ethnicity with increased Alzheimer's disease rates should not be interpreted as surrogates of genetic ancestry or considered to represent African-derived populations from the developing nations such as Brazil.
Asunto(s)
Enfermedad de Alzheimer , Población Negra/genética , Enfermedades del Sistema Nervioso/etiología , Enfermedades del Sistema Nervioso/genética , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/complicaciones , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/patología , Apolipoproteínas E/genética , Infarto Encefálico/etiología , Infarto Encefálico/genética , Brasil/epidemiología , Brasil/etnología , Femenino , Interacción Gen-Ambiente , Genotipo , Humanos , Masculino , Persona de Mediana Edad , Ovillos Neurofibrilares/patología , Oportunidad Relativa , Placa Amiloide/patología , Estudios Retrospectivos , Factores de Riesgo , Estadísticas no ParamétricasRESUMEN
Currently, the effect of crude oil on ammonia-oxidizing bacterium communities from mangrove sediments is little understood. We studied the diversity of ammonia-oxidizing bacteria in mangrove microcosm experiments using mangrove sediments contaminated with 0.1, 0.5, 1, 2, and 5% crude oil as well as non-contaminated control and landfarm soil from near an oil refinery in Camamu Bay in Bahia, Brazil. The evolution of CO(2) production in all crude oil-contaminated microcosms showed potential for mineralization. Cluster analysis of denaturing gradient gel electrophoresis-derived samples generated with primers for gene amoA, which encodes the functional enzyme ammonia monooxygenase, showed differences in the sample contaminated with 5% compared to the other samples. Principal component analysis showed divergence of the non-contaminated samples from the 5% crude oil-contaminated sediment. A Venn diagram generated from the banding pattern of PCR-denaturing gradient gel electrophoresis was used to look for operational taxonomic units (OTUs) in common. Eight OTUs were found in non-contaminated sediments and in samples contaminated with 0.5, 1, or 2% crude oil. A Jaccard similarity index of 50% was found for samples contaminated with 0.1, 0.5, 1, and 2% crude oil. This is the first study that focuses on the impact of crude oil on the ammonia-oxidizing bacterium community in mangrove sediments from Camamu Bay.
