Expression of the putative ORF1 capsid protein of Torque teno sus virus 2 (TTSuV2) and development of Western blot and ELISA serodiagnostic assays: correlation between TTSuV2 viral load and IgG antibody level in pigs.
ABSTRACT Porcine Torque teno virus (TTV) has a single-stranded circular DNA genome and is currently classified into a new genus Iotatorquevirus with two species in a newly established family Anelloviridae. Viral DNA of both porcine TTV species (TTSuV1 and TTSuV2) has a high prevalence in both healthy and diseased pigs worldwide and multiple infections of TTSuV with distinct genotypes or subtypes of the same species has been documented in the United States and in Europe. However, the prevalence of specific TTSuV antibodies in pigs remains unknown. In this study, the putative ORF1 capsid protein from TTSuV2 isolate PTTV2c-VA was expressed in Escherichia coli. The purified recombinant ORF1 protein was used as the antigen for the development of Western blot and indirect ELISA to detect TTSuV2-specific IgG antibodies in pig sera. The results revealed a relatively high rate of seropositivity to TTSuV2 in conventional pigs from different sources but not in gnotobiotic pigs. Overall, pigs with undetectable TTSuV2 viral load were more likely to have a lower anti-TTSuV2 antibody level. An analysis of 10 conventional pigs during a 2-month period showed that decreased viral loads or presumed virus clearance were associated with elevated anti-ORF1 IgG antibody levels. Interestingly, porcine circovirus associated disease (PCVAD)-affected pigs had a significantly lower level of TTSuV2 antibody than PCVAD-unaffected pigs (p<0.01). This is the first study to establish essential serodiagnostic tools for investigation of TTSuV seroprevalence and infection dynamics, which will help elucidate the potential pathogenicity of TTSuV infection in pigs.
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ABSTRACT: The technical performance of lignocellulosic enzymatic hydrolysis and fermentation versus pyrolysis processes for sugarcane bagasse was evaluated, based on currently available technology. Process models were developed for bioethanol production from sugarcane bagasse using three different pretreatment methods, i.e. dilute acid, liquid hot water and steam explosion, at various solid concentrations. Two pyrolysis processes, namely fast pyrolysis and vacuum pyrolysis, were considered as alternatives to biological processing for the production of biofuels from sugarcane bagasse. For bioethanol production, a minimum of 30% solids in the pretreatment reactor was required to render the process energy self-sufficient, which led to a total process energy demand equivalent to roughly 40% of the feedstock higher heating value. Both vacuum pyrolysis and fast pyrolysis could be operated as energy self-sufficient if 45% of the produced char from fast pyrolysis is used to fuel the process. No char energy is required to fuel the vacuum pyrolysis process due to lower process energy demands (17% compared to 28% of the feedstock higher heating value). The process models indicated that effective process heat integration can result in a 10–15% increase in all process energy efficiencies. Process thermal efficiencies between 52 and 56% were obtained for bioethanol production at pretreatment solids at 30% and 50%, respectively, while the efficiencies were 70% for both pyrolysis processes. The liquid fuel energy efficiency of the best bioethanol process is 41%, while that of crude bio-oil production before upgrading is 67% and 56% via fast and vacuum pyrolysis, respectively. Efficiencies for pyrolysis processes are expected to decrease by up to 15% should upgrade to a transportation fuel of equivalent quality to bioethanol be taken into consideration.Biomass & Bioenergy - BIOMASS BIOENERG. 01/2011; 35(5):2117-2126.