Improving simultaneous saccharification and co-fermentation of pretreated wheat straw using both enzyme and substrate feeding

<p>Abstract</p> <p>Background</p> <p>Simultaneous saccharification and co-fermentation (SSCF) has been recognized as a feasible option for ethanol production from xylose-rich lignocellulosic materials. To reach high ethanol concentration in the broth, a high content of water-insoluble solids (WIS) is needed, which creates mixing problems and, furthermore, may decrease xylose uptake. Feeding of substrate has already been proven to give a higher xylose conversion than a batch SSCF. In the current work, enzyme feeding, in addition to substrate feeding, was investigated as a means of enabling a higher WIS content with a high xylose conversion in SSCF of a xylose-rich material. A recombinant xylose-fermenting strain of <it>Saccharomyces cerevisiae </it>(TMB3400) was used for this purpose in fed-batch SSCF experiments of steam-pretreated wheat straw.</p> <p>Results</p> <p>By using both enzyme and substrate feeding, the xylose conversion in SSCF could be increased from 40% to 50% in comparison to substrate feeding only. In addition, by this design of the feeding strategy, it was possible to process a WIS content corresponding to 11% in SSCF and obtain an ethanol yield on fermentable sugars of 0.35 g g^-1.</p> <p>Conclusion</p> <p>A combination of enzyme and substrate feeding was shown to enhance xylose uptake by yeast and increase overall ethanol yield in SSCF. This is conceptually important for the design of novel SSCF processes aiming at high-ethanol titers. Substrate feeding prevents viscosity from becoming too high and thereby allows a higher total amount of WIS to be added in the process. The enzyme feeding, furthermore, enables keeping the glucose concentration low, which kinetically favors xylose uptake and results in a higher xylose conversion.</p

Ricin Toxicokinetics and Its Sensitive Detection in Mouse Sera or Feces Using Immuno-PCR

Ricin (also called RCA-II or RCA(60)), one of the most potent toxins and documented bioweapons, is derived from castor beans of Ricinus communis. Several in vitro methods have been designed for ricin detection in complex food matrices in the event of intentional contamination. Recently, a novel Immuno-PCR (IPCR) assay was developed with a limit of detection of 10 fg/ml in a buffer matrix and about 10-1000-fold greater sensitivity than other methods in various food matrices.In order to devise a better diagnostic test for ricin, the IPCR assay was adapted for the detection of ricin in biological samples collected from mice after intoxication. The limit of detection in both mouse sera and feces was as low as 1 pg/ml. Using the mouse intravenous (iv) model for ricin intoxication, a biphasic half-life of ricin, with a rapid t(1/2)α of 4 min and a slower t(1/2)β of 86 min were observed. The molecular biodistribution time for ricin following oral ingestion was estimated using an antibody neutralization assay. Ricin was detected in the blood stream starting at approximately 6-7 h post- oral intoxication. Whole animal histopathological analysis was performed on mice treated orally or systemically with ricin. Severe lesions were observed in the pancreas, spleen and intestinal mesenteric lymph nodes, but no severe pathology in other major organs was observed.The determination of in vivo toxicokinetics and pathological effects of ricin following systemic and oral intoxication provide a better understanding of the etiology of intoxication and will help in the future design of more effective diagnostic and therapeutic methods

A Single-Stranded DNA Aptamer That Selectively Binds to Staphylococcus aureus Enterotoxin B

The bacterium Staphylococcus aureus is a common foodborne pathogen capable of secreting a cocktail of small, stable, and strain-specific, staphylococcal enterotoxins (SEs). Staphylococcal food poisoning (SFP) results when improperly handled food contaminated with SEs is consumed. Gastrointestinal symptoms of SFP include emesis, diarrhea and severe abdominal pain, which manifest within hours of ingesting contaminated food. Immuno-affinity based methods directly detect, identify, and quantify several SEs within a food or clinical sample. However, the success of these assays depends upon the availability of a monoclonal antibody, the development of which is non-trivial and costly. The current scope of the available immuno-affinity based methods is limited to the classical SEs and does not encompass all of the known or emergent SEs. In contrast to antibodies, aptamers are short nucleic acids that exhibit high affinity and specificity for their targets without the high-costs and ethical concerns of animal husbandry. Further, researchers may choose to freely distribute aptamers and develop assays without the proprietary issues that increase the per-sample cost of immuno-affinity assays. This study describes a novel aptamer, selected in vitro, with affinity to staphylococcal enterotoxin B (SEB) that may be used in lieu of antibodies in SE detection assays. The aptamer, designated APTSEB1, successfully isolates SEB from a complex mixture of SEs with extremely high discrimination. This work sets the foundation for future aptamer and assay development towards the entire family of SEs. The rapid, robust, and low-cost identification and quantification of all of the SEs in S. aureus contaminated food is essential for food safety and epidemiological efforts. An in vitro generated library of SE aptamers could potentially allow for the comprehensive and cost-effective analysis of food samples that immuno-affinity assays currently cannot provide

Potential relevance of salivary legumain for the clinical diagnostic of hand, foot, and mouth disease

10.1002/jmv.29243Journal of Medical Virology9511e29243

Avaliação da atenção secundária em saúde bucal: uma investigação nos centros de especialidades do Brasil Evaluation of secondary care in oral health: a study of specialty clinics in Brazil

Este trabalho discorre a respeito da avaliação da atenção secundária no âmbito da vigilância em saúde. Estudo descritivo, de caráter avaliativo normativo. Para análise de desempenho, foram utilizados dados secundários, com base na série histórica da produção de procedimentos odontológicos realizados nos CEO implantados no país e registrados pelo SIA/SUS no ano de 2007, e dados primários, pela visita in loco de 10% dos serviços implantados, com uso de questionários dirigidos à equipe profissional do CEO. Dentre os CEO analisados, observou-se que na maioria das regiões houve dificuldade no cumprimento das metas relativas à quantidade de procedimentos a serem informados no SIA/SUS. Sendo a Região Norte com menor percentual de serviços implantados. O indicador Cumprimento da Atenção Secundária em Saúde Bucal foi de 64,4%. Os CEO tipo III tiveram melhores resultados para o desempenho e cumprimento das metas. Foi evidenciada a necessidade de revisão no marco legal para a implantação dos CEO pela readequação dos critérios e normas, como também definições de novos padrões e cumprimento de metas para avaliação e monitoramento desses serviços.<br>This article discusses the evaluation of secondary care in the area of health surveillance. This was a descriptive and normative/evaluative study. Performance analysis drew on secondary data, based on a historical series of dental procedures conducted at the specialized dental clinics implemented in Brazil and recorded by the Outpatient Information System of the Unified National Health System (SIA/SUS) in 2007, as well as primary data from site visits to the clinics, based on questionnaires completed by clinic staff. Performance of the clinics was poor in most regions of the country, and the North of Brazil had the lowest percentage of specialty services implemented. The indicator "Performance of Secondary Care in Oral Health" was 64.4%. The type 3 specialty clinics showed better results in terms of performance and achievement of targets. The study showed the need to review the legal framework for implementing specialized dental clinics by adjusting the criteria and norms, as well as definition of new standards for achievement of goals in the evaluation and monitoring of these services