Over the past years, bottom-up bionanotechnology has been developed as a promising tool for future technological applications. Many of these biomolecule-based assemblies are characterized using various single-molecule techniques that require strict anaerobic conditions. The most common oxygen scavengers for single-molecule experiments are glucose oxidase and catalase (GOC) or protocatechuate dioxygenase (PCD). One of the pitfalls of these systems, however, is the production of carboxylic acids. These acids can result in a significant pH drop over the course of experiments and must thus be compensated by an increased buffer strength. Here, we present pyranose oxidase and catalase (POC) as a novel enzymatic system to perform single-molecule experiments in pH-stable conditions at arbitrary buffer strength. We show that POC keeps the pH stable over hours, while GOC and PCD cause an increasing acidity of the buffer system. We further verify in single-molecule fluorescence experiments that POC performs as good as the common oxygen-scavenging systems, but offers long-term pH stability and more freedom in buffer conditions. This enhanced stability allows the observation of bionanotechnological assemblies in aqueous environments under well-defined conditions for an extended time.

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We performed a systematic review and meta-analysis to determine whether diabetic patients have an increased rate of postoperative complications compared to nondiabetic patients after head and neck free flap reconstruction. A systematic review of PubMed Database between 1966 and 2012 was performed. RevMan 5.0 was used for meta-analysis. A retrospective medical chart review of 7890 patients to identify those who had a failed microsurgical reconstruction of the head and neck region at Chang Gung Memorial Hospital was also carried out. The result revealed that patients with diabetes mellitus have a 1.76 increased risk of complications (odds ratio [OR] = 1.76; 95% confidence interval [CI] = 1.11-2.79) with minimal heterogeneity (I( 2)  = 22%; p = .28). The prevalence of diabetes mellitus in patients with failed free flaps for head and neck reconstruction is 15%. The incidence of diabetes mellitus in these patients with failed free flaps is 2.3 times higher than in the general population.

SummaryHelicobacter pylori infection is an aetiological cause of gastric disorders worldwide. H. pylori has been shown to assimilate and convert host cholesterol into cholesteryl glucosides (CGs) by cholesterol-aglucosyltransferase encoded by capJ. Here, we show that CapJ-deficient (DcapJ) H. pylori resulted in greatly reduced type IV secretion system (TFSS)-associated activities, including the hummingbird phenotype of AGS cells, IL-8 production, CagA translocation/phosphorylation and CagA-mediated signalling events. Complementation of the DcapJ mutation with wild type cagJ or by adding CGs-containing lysates or exogenous fluorophore-tagged CGs reversed the mutant phenotypes. We also show that the wild-type but not DcapJ H. pylori recruited raft-associated components to sites of bacterial attachment. Fluorescence recovery after photobleaching (FRAP) analysis of AGS cells treated with fluorescence-tagged cholesterol/CGs revealed that there was a higher proportion of CGs associated with immobile fractions. CGs-associated membranes were also more resistant to a cold detergent extraction. Thus, we propose that CGs synthesized by H. pylori around host-pathogen contact sites partition in detergent-resistant membranes (DRMs), alters lateralphase segregation in membrane and reorganizes membrane architecture. These processes together promote the formation of a functional TFSS and H. pylori infection.