190 research outputs found

    Hepatitis B virus genotypes and evolutionary profiles from blood donors from the northwest region of China

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    Hepatitis B virus (HBV) is prevalent in China and screening of blood donors is mandatory. Up to now, ELISA has been universally used by the China blood bank. However, this strategy has sometimes failed due to the high frequency of nucleoside acid mutations. Understanding HBV evolution and strain diversity could help devise a better screening system for blood donors. However, this kind of information in China, especially in the northwest region, is lacking. In the present study, serological markers and the HBV DNA load of 11 samples from blood donor candidates from northwest China were determined. The HBV strains were most clustered into B and C genotypes and could not be clustered into similar types from reference sequences. Subsequent testing showed liver function impairment and increasing virus load in the positive donors. This HBV evolutionary data for China will allow for better ELISA and NAT screening efficiency in the blood bank of China, especially in the northwest region

    Dynamics of Seed-Borne Rice Endophytes on Early Plant Growth Stages

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    Bacterial endophytes are ubiquitous to virtually all terrestrial plants. With the increasing appreciation of studies that unravel the mutualistic interactions between plant and microbes, we increasingly value the beneficial functions of endophytes that improve plant growth and development. However, still little is known on the source of established endophytes as well as on how plants select specific microbial communities to establish associations. Here, we used cultivation-dependent and -independent approaches to assess the endophytic bacterrial community of surface-sterilized rice seeds, encompassing two consecutive rice generations. We isolated members of nine bacterial genera. In particular, organisms affiliated with Stenotrophomonas maltophilia and Ochrobactrum spp. were isolated from both seed generations. PCR-based denaturing gradient gel electrophoresis (PCR-DGGE) of seed-extracted DNA revealed that approximately 45% of the bacterial community from the first seed generation was found in the second generation as well. In addition, we set up a greenhouse experiment to investigate abiotic and biotic factors influencing the endophytic bacterial community structure. PCR-DGGE profiles performed with DNA extracted from different plant parts showed that soil type is a major effector of the bacterial endophytes. Rice plants cultivated in neutral-pH soil favoured the growth of seed-borne Pseudomonas oryzihabitans and Rhizobium radiobacter, whereas Enterobacter-like and Dyella ginsengisoli were dominant in plants cultivated in low-pH soil. The seed-borne Stenotrophomonas maltophilia was the only conspicuous bacterial endophyte found in plants cultivated in both soils. Several members of the endophytic community originating from seeds were observed in the rhizosphere and surrounding soils. Their impact on the soil community is further discussed

    Knowledge actors and the construction of new governing panoramas:The case of the European Commission’s DG Education and Culture

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    RESUMO: Este artigo aborda o tema da governança da educação na Europa. Esse espaço da política tem sido dominado por grandes interesses e organizações transnacionais, entre as quais se destacam a Organização para a Cooperação e Desenvolvimento Econômico (OCDE) e a Comissão Europeia (CE). Este artigo procura explorar e explicar quais são os efeitos constitutivos que as práticas sistemáticas de 'medição' e de estandardização têm na intensificação da convergência entre a Direção-Geral de Educação e Cultura da CE e a OCDE, a qual, por meio do PISA e de outros testes internacionais, tornou-se um ator influente na política educativa em uma escala global. O artigo pretende identificar os feitos do 'governo pelos números' nas interdependências criadas entre as duas organizações internacionais

    Perspectives on the use of transcriptomics to advance biofuels

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    As a field within the energy research sector, bioenergy is continuously expanding. Although much has been achieved and the yields of both ethanol and butanol have been improved, many avenues of research to further increase these yields still remain. This review covers current research related with transcriptomics and the application of this high-throughput analytical tool to engineer both microbes and plants with the penultimate goal being better biofuel production and yields. The initial focus is given to the responses of fermentative microbes during the fermentative production of acids, such as butyric acid, and solvents, including ethanol and butanol. As plants offer the greatest natural renewable source of fermentable sugars within the form of lignocellulose, the second focus area is the transcriptional responses of microbes when exposed to plant hydrolysates and lignin-related compounds. This is of particular importance as the acid/base hydrolysis methods commonly employed to make the plant-based cellulose available for enzymatic hydrolysis to sugars also generates significant amounts of lignin-derivatives that are inhibitory to fermentative bacteria and microbes. The article then transitions to transcriptional analyses of lignin-degrading organisms, such as Phanerochaete chrysosporium, as an alternative to acid/base hydrolysis. The final portion of this article will discuss recent transcriptome analyses of plants and, in particular, the genes involved in lignin production. The rationale behind these studies is to eventually reduce the lignin content present within these plants and, consequently, the amount of inhibitors generated during the acid/base hydrolysis of the lignocelluloses. All four of these topics represent key areas where transcriptomic research is currently being conducted to identify microbial genes and their responses to products and inhibitors as well as those related with lignin degradation/formation.clos

    Evaluation of three second-generation and three confirmatory assays for antibodies to human immunodeficiency virus

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    The second-generation enzyme immunoassays (EIAs) for antibodies against human immunodeficiency virus (HIV) from three manufacturers (Abbott, Organon, Wellcome) and three anti-HIV confirmatory tests, i.e. Western Blot (WB, Biotech, Dupont), radioimmunoprecipitation assay (RIPA, CLB) and a competitive immunoassay (CIA, Abbott) were evaluated on a panel of 6,488 serum samples, which had previously been used for the comparison of seven first-generation EIAs. For the present study the panel was expanded with sequential serum samples from 12 individuals followed at 1- to 3-month intervals during seroconversion for anti-HIV. The second-generation EIAs and confirmatory tests were significantly more sensitive than the first-generation EIAs as was demonstrated by detection of 10- to 100-fold higher endpoint titers in anti-HIV-positive sera as well as by earlier detection of anti-HIV in 7-11 of the 12 subjects, who seroconverted. In all sera obtained during early HIV infection anti-gp 160/120env antibodies (WB, CIA) were found in addition to anti-p24 (WB, RIPA) and in serial twofold dilutions of these 'seroconversion samples' the new Abbott EIA and RIPA were significantly more sensitive than WB (p less than 0.05), whereas CIA and the new Organon EIA were significantly less sensitive than WB (p less than 0.05). The new Wellcome EIA was not statistically less sensitive than WB. The CIA was as sensitive as WB for antibodies to envelope proteins (gp41, gp160, gp120), but considerably less sensitive for core (p24) antibodies, as was shown in sera obtained during early as well as later clinical stages of HIV infection.(ABSTRACT TRUNCATED AT 250 WORDS

    Inactivation of 12 viruses by heating steps applied during manufacture of a hepatitis B vaccine

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    The efficacy of two heating cycles (90 sec at 103 degrees C and 10 hr at 65 degrees C) used during manufacture of a plasma-derived hepatitis-B vaccine was validated for the inactivation of 12 virus families. A period of 15 min warming up to 65 degrees C had already completely inactivated representatives of nine virus families, ie, poxvirus (vaccinia), picornavirus (encephalomyocarditis virus), togavirus (sindbis virus), coronavirus (mouse hepatitis virus), orthomyxovirus (influenza virus), rhabdovirus (vesicular stomatitis virus), herpes virus (cytomegalovirus), lentivirus (human immunodeficiency virus), and retrovirus (murine leukemia virus). After prolonged heating at 65 degrees C or heating for 90 sec at 103 degrees C, parvovirus (canine parvovirus) and the phage phiX174 were also completely inactivated. Papovavirus represented by simian virus 40 (SV-40) was the most heat-resistant virus evaluated. The infectivity of SV-40 was reduced by 10(4) Tissue Culture Infectious Doses (TCID50) per ml after 90 sec at 103 degrees C, but a marginal residual activity (less than 1.5 TCID50 per ml) was observed. Subsequent pasteurization for 10 h at 65 degrees C did not further reduce the infectivity of SV-40. This study shows that the two heat-inactivation steps used during the production of this vaccine kill a wide variety of viruses that might be present in human bloo
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