ABSTRACT
Aim: The aim of the present study was to identify and characterize the functions of key microbes mediating nitrification.Methodology: After sampling the biofilm from a submerged biofilter in a marine aquaculture system, selective media were used to isolate microbial strains involved in nitrification. Isolates were identified using physiological and biochemical assays and sequencing of 16S rRNA gene. Nitrogen removal under different conditions was characterized. Nitrogen removal pathway was characterized by a 15N tracer experiment. Representation of key microbes in the biolfim was characterized by metagenomics analysis. Results: Single-factor tests showed that Halomonas sp. strain Z8 exhibited good heterotrophic nitrification and aerobic denitrification abilities, with maximum NH4+-N, NO2--N and No3--N removal rates of 2.37, 1.28 and 1.7 mg N l-1 hr-1, respectively. The 15N isotope tracer experiment confirmed the aerobic nitrogen removal pathway of strain Z8. Average NO3-removal efficiencies were all above 80% in an aerated moving bed bioreactor inoculated with strain Z8 and employed to treat synthetic marine aquaculture wastewater. Metagenomic microbial community analysis revealed that Halomonas sp. Z8 was one of the dominant taxa at genus level, suggesting a vital role in removing nitrate from bioreactor
ABSTRACT
In this study, neem leaves were successively extracted with petroleum ether, 95% ethanol and water and the insecticidal activities of these extracts against Oxya chinensis larvae were measured. The results showed that 95% ethanol extract gave the highest extraction yield and insecticidal activity, and it was further extracted with five different solvents. The petroleum ether extract from the 95% ethanol extract possessed the highest insecticidal activity with median lethal concentration values ranging from 14.93 to 55.66mg/mL. The gas chromatography-mass spectrometer analysis showed that the petroleum ether extract mainly composed of alkanes, olefin, esters and amide. The pathological examination revealed that the prominent lesions, including reduced regenerative cells in midgut and swelled and degenerated cylindrical cells, were observed in the 5th instar Oxya chinensis after treatment. The ultrastructural features showed that the cylindrical cells, microvilli and mitochondria were seriously damaged. These results suggested that the petroleum ether extract from neem leaves had potent insecticidal activity and could be a candidate insecticide.(AU)
Nesse estudo, folhas "neem" foram extraídas com sucesso com éter de petróleo, 95% de etanol e água, e as atividades inseticidas desses extratos foram medidas contra larvas de Oxya chinesis. Os resultados mostram que extrato com 95% de etanol deram o maior resultado de extração e atividade inseticida e foi então extraído utilizando mais cinco diferentes solventes. O éter de petróleo do extrato de 95% etanol apresentou maior atividade inseticida com concentração letal média variando de 14.93 a 55.66mg/mL. A análise por cromatografia de massa mostrou que o extrato de éter de petróleo está composto principalmente de alcanos, alcenos, ésteres e amidas. A avaliação patológica revelou que as lesões proeminentes, inclusive células regenerativas reduzidas no intestino e células cilíndricas edemaciadas e degeneradas foram observadas no quinto estágio de desenvolvimento da Oxya chinesis após tratamento. As características ultraestruturais mostraram que as células cilíndricas, microvilos e mitocôndrias apresentavam lesões graves. Esses resultados sugerem que o extrato de éter de petróleo de folhas de "neem" tem atividade inseticida potente e pode ser um candidato a inseticida.(AU)
Subject(s)
Azadirachta/physiology , Insecticides/analysisABSTRACT
Scarce information is available about the seroprevalence of Toxoplasma gondii (T. gondii) and Neospora caninum (N. caninum) infections in goats in Hubei province, China. In the present study, the prevalence of T. gondii and N. caninum infections in goats were investigated in Hubei province, China between 2014 and 2015. A total 2007 serum samples were collected from 6 counties of Hubei province, China and were tested for antibodies to N. caninum and T. gondii by an enzyme-linked immunosorbent assay (ELISA) and an indirect agglutination test (IAT), respectively. Antibodies against T. gondii and N. caninum were detected in 13.4% and 3.9%, respectively in goats. 2% (41) serum samples were positive to both parasites. There was no apparent association of T. gondii and N. caninum infection with gender of the animals. There were significant differences of T. gondii (p < 0.01), N. caninum (p < 0.05) and both parasites (p < 0.01) infection with season. This is the first time that antibodies to T. gondii and N. caninum have been detected in goats in Hubei province, China.