Influência de cinco cultivares de soja no consumo, desenvolvimento, fecundidade e fertilidade de Anticarsia gemmatalis.

O presente trabalho foi conduzido em condições de laboratório, à temperatura de 29 + 2,5oC, fotoperíodo de 15 horas e umidade de 70 + 10%, no Centro Nacional de Pesquisa de Trigo, da EMBRAPA, localizado no município de Passo Fundo, RS, durante 1980/81. Teve como objetivo avaliar o efeito das cultivares de soja (Glycine max (L.) Merrill) "Paraná", "Cobb", "BR 1", "BR 3" e "BR 4", durante o período vegetativo tardio das plantas, no consumo, desenvolvimento, fecundidade e fertilidade de Anticarsia gemmatalis Hubner (1818). Constatou-se a influência do sexo no consumo e na duração total das fases imaturas. Observaram-se também efeitos significativos das cultivares no consumo e eficiência de conversão do alimento ingerido pelas lagartas, na duração total das fases imaturas, na taxa de fertilidade e potencial biótico. Ficou evidenciada a maior resistência da "Cobb" e menor da "BR 3 e "BR 4" à lagarta-da-soja

Nitrate addition to groundwater impacted by ethanol-blended fuel accelerates ethanol removal and mitigates the associated metabolic flux dilution and inhibition of BTEX biodegradation

A comparison of two controlled ethanol-blended fuel releases under monitored natural attenuation (MNA) versus nitrate biostimulation (NB) illustrates the potential benefits of augmenting the electron acceptor pool with nitrate to accelerate ethanol removal and thus mitigate its inhibitory effects on BTEX biodegradation. Groundwater concentrations of ethanol and BTEX were measured 2 m downgradient of the source zones. In both field experiments, initial source-zone BTEX concentrations represented less than 5% of the dissolved total organic carbon (TOC) associated with the release, and measurable BTEX degradation occurred only after the ethanol fraction in the multicomponent substrate mixture decreased sharply. However, ethanol removal was faster in the nitrate amended plot (1.4 years) than under natural attenuation conditions (3.0 years), which led to faster BTEX degradation. This reflects, in part, that an abundant substrate (ethanol) can dilute the metabolic flux of target pollutants (BTEX) whose biodegradation rate eventually increases with its relative abundance after ethanol is preferentially consumed. The fate and transport of ethanol and benzene were accurately simulated in both releases using RT3D with our general substrate interaction module (GSIM) that considers metabolic flux dilution. Since source zone benzene concentrations are relatively low compared to those of ethanol (or its degradation byproduct, acetate), our simulations imply that the initial focus of cleanup efforts (after free-product recovery) should be to stimulate the degradation of ethanol (e.g., by nitrate addition) to decrease its fraction in the mixture and speed up BTEX biodegradation.Petróleo Brasileiro S/A — PETROBRASCoordination of Improvement of Higher Education Personnel (CAPES)National Council for Scientific and Technological Development (CNPq

Occurrence and distribution of polycyclic aromatic hydrocarbons in surface water of Todos os Santos Bay, Bahia, Brazil

  Quatorze dos hidrocarbonetos policíclicos aromáticos (HPA) incluídos pelo Environmental Protection Agency (EPA) na lista de poluentes prioritários foram analisados através de cromatografia gasosa com espectrometria de massas acoplada (GC-MS). A amostragem das águas superficiais foi realizada na Baía de Todos os Santos (Bahia), norte do Brasil. Os perfis foram dominados por HPAs de alto peso molecular (quatro ou cinco anéis de componentes) em amostras de água superficial; indicativo de sua origem a partir de óleo ou contaminação residual (entrada pirogênica). Para discriminar diferenças e semelhanças entre as amostras, a análise de componente principal foi realizada utilizando uma matriz de correlação

Degradation of a benzene–toluene mixture by hydrocarbon-adapted bacterial communities

We examined the rate of degradation of a benzene–toluene mixture in aerobic microcosms prepared with samples of an aquifer that lies below a petrochemical plant (SIReN, UK). Five samples exposed to different concentrations of benzene (from 0.6 to 317 mg l−1) were used. Fast degradation (approx. 1–6 mg l−1 day−1) of both contaminants was observed in all groundwater samples and complete degradation was recorded by the seventh day except for one sample. We also identified the microbial community in each of the samples by culture-independent techniques. Two of the less impacted samples harbour the aerobic benzene degrader Pseudomonas fluorescens, while Acidovorax and Arthrobacter spp. were found in the most polluted sample and are consistent with the population observed in situ. Hydrogenophaga was found in the deepest sample while Rhodoferax spp. were recovered in an alkaline sample (pH 8.4) and may also be implicated in benzene degradation. Time series analysis shows that each of the samples has a different community but they remain stable over the degradation period. This study provides new information on a well not previously studied (no. 309s) and confirms that adapted communities have the ability to degrade hydrocarbon mixtures and could be used in further bioaugmentation approaches in contaminated sites