A Functional Genomics Approach to Establish the Complement of Carbohydrate Transporters in Streptococcus pneumoniae

The aerotolerant anaerobe Streptococcus pneumoniae is part of the normal nasopharyngeal microbiota of humans and one of the most important invasive pathogens. A genomic survey allowed establishing the occurrence of twenty-one phosphotransferase systems, seven carbohydrate uptake ABC transporters, one sodium∶solute symporter and a permease, underlining an exceptionally high capacity for uptake of carbohydrate substrates. Despite high genomic variability, combined phenotypic and genomic analysis of twenty sequenced strains did assign the substrate specificity only to two uptake systems. Systematic analysis of mutants for most carbohydrate transporters enabled us to assign a phenotype and substrate specificity to twenty-three transport systems. For five putative transporters for galactose, pentoses, ribonucleosides and sulphated glycans activity was inferred, but not experimentally confirmed and only one transport system remains with an unknown substrate and lack of any functional annotation. Using a metabolic approach, 80% of the thirty-two fermentable carbon substrates were assigned to the corresponding transporter. The complexity and robustness of sugar uptake is underlined by the finding that many transporters have multiple substrates, and many sugars are transported by more than one system. The present work permits to draw a functional map of the complete arsenal of carbohydrate utilisation proteins of pneumococci, allows re-annotation of genomic data and might serve as a reference for related species. These data provide tools for specific investigation of the roles of the different carbon substrates on pneumococcal physiology in the host during carriage and invasive infection

A Ray Tracing based Framework for High-Quality Virtual Reality in Industrial Design Applications

Computer aided design (CAD) and virtual reality (VR) are becoming increasingly important tools for industrial design applications. Unfortunately, there is a huge and growing gap between what data CAD engineers are working on, what rendering quality is needed by designers and executives to faithfully judge a design variant, and what rendering capabilities are offered by commonly available VR frameworks. In particular, existing VR systems cannot currently cope with the accuracy demanded by CAD engineers, nor can they deliver the photo-realistic rendering quality and reliability required by designers and decision makers. In this paper, we describe a ray tracing based virtual reality framework that closes these gaps. In particular, the proposed system supports direct ray tracing of trimmed freeform surfaces even for complex models of thousands of patches, allows for accurately simulating reflections and refraction for glass and car paint effects, offers support for direct integration of measured materials via bidirectional texture functions, and even allows for soft environmental lighting from high dynamic range environment maps. All of these effects can be delivered interactively, and are demonstrated on a real-world industrial model, a complete Mercedes C-Class car