Controlled Silanization Using Functional Silatrane for Thin and Homogeneous Antifouling Coatings.

Organosilicons for surface modification are gaining prominence because of their easy and rapid preparation, high availability, and effective modification for varying interfacial properties. However, their implementation has been humbled by poor control of the packing density, thickness, and molecular structures due to the uncontrollable hydrolysis and condensation. This study reports for the first time new functional silatrane chemistry for the precision deposition of a thin and homogeneous zwitterionic coating. Sulfobetaine silatrane (SBSiT) has a tricyclic caged structure and a transannular N → Si dative bond, which shows excellent chemical stability in the presence of water and an acid-modulated hydrolysis characteristic. Results from X-ray photoelectron spectroscopy indicate the progressive deposition of SBSiT on a silicon surface. Characterization using atomic force microscopy and ellipsometry shows the uniform and thin SBSiT films on silicon surfaces. The superior antifouling properties of SBSiT coatings were demonstrated by resisting bacterial and protein adsorption. More importantly, the stable and complete formation of the SBSiT coatings allows an accurate interpretation of the interfacial phenomena for sensing and nanomaterial applications.

Comparative Evaluation of Standard RT-PCR Assays and Commercial Real-Time RT-PCR Kits for Detection of Lassa Virus.

Lassa virus (LASV) is a causative agent of hemorrhagic fever epidemic in West Africa. In recent years, it has been transmitted several times to North America, Europe, and Asia. Standard reverse transcription (RT)-PCR and real-time RT-PCR are extensively used for early detection of LASV. However, the high nucleotide diversity of LASV strains complicates the development of appropriate diagnostic assays. Here, we analyzed LASV diversity clustered with geographic location and evaluated the specificity and sensitivity of two standard RT-PCR methods (GPC RT-PCR/1994 and 2007) and four commercial real-time RT-PCR kits (namely, Da an, Mabsky, Bioperfectus, and ZJ) to detect six representative LASV lineages using in vitro synthesized RNA templates. The results showed that the GPC RT-PCR/2007 assay had better sensitivity compared to the GPC RT-PCR/1994 assay. The Mabsky and ZJ kits were able to detect all RNA templates of six LASV lineages. Contrastingly, the Bioperfectus and Da an kits failed to detect lineages IV and V/VI. The limit of detection for lineage I with the Da an, Bioperfectus, and ZJ kits were significantly higher than that of the Mabsky kit at an RNA concentration of 1 × 1010 to 1 × 1011 copies/mL. The Bioperfectus and Da an kits detected lineages II and III at an RNA concentration of 1 × 109 copies/mL, higher than that of the other kits. In conclusion, the GPC RT-PCR/2007 assay and the Mabsky kit were suitable assays for the detection of LASV strains based on good analytical sensitivity and specificity. IMPORTANCE Lassa virus (LASV) is a significant human pathogen causing hemorrhagic fever in West Africa. Increased traveling around the world raises the risk of imported cases to other countries. The high nucleotide diversity of LASV strains clustered with geographic location complicates the development of appropriate diagnostic assays. In this study, we showed that the GPC reverse transcription (RT)-PCR/2007 assay and the Mabsky kit are suitable for detecting most LASV strains. Future assays for molecular detection of LASV should be based on specific countries/regions along with new variants.

Huntingtin-associated protein 1 plays an essential role in the pathogenesis of type 2 diabetes by regulating the translocation of GLUT4 in mouse adipocytes.

OBJECTIVE: Glucose disposal by insulin-responsive tissues maintains the body glucose homeostasis and insulin resistance leads to a risk of developing type 2 diabetes (T2DM). Insulin stimulates the translocation of glucose transporter isoform 4 (GLUT4) vesicles from intracellular compartments to the plasma membrane to facilitate glucose uptake. However, the underlying mechanisms of GLUT4 vesicle translocation are not well defined. Here we show the role of huntingtin-associated protein 1 (HAP1) in GLUT4 translocation in adipocytes and the pathogenesis of T2DM. RESEARCH DESIGN AND METHODS: The parameters for glucose metabolism including body weight, glucose tolerance and insulin tolerance were assessed in wild-type (WT) and Hap1+/- mice. HAP1 protein expression was verified in adipose tissue. Hap1 mRNA and protein expression was monitored in adipose tissue of high-fat diet (HFD)-induced diabetic mice. Insulin-stimulated GLUT4 vesicle translocation and glucose uptake were detected using immunofluorescence techniques and quantified in primary adipocytes from Hap1-/- mice. The interaction between HAP1 and GLUT4 was assessed by immunofluorescence colocalization and co-immunoprecipitation in HEK293 cells and adipose tissue. The role of sortilin in HAP1 and GLUT4 interaction was approved by co-immunoprecipitation and RNA interference. RESULTS: The expression of Hap1 mRNA and protein was detected in WT mouse adipose tissue and downregulated in adipose tissue of HFD-induced diabetic mice. Hap1+/- mice exhibited increased body weight, pronounced glucose tolerance and significant insulin intolerance compared with the WT mice. HAP1 colocalized with GLUT4 in mouse adipocytes and cotransfected HEK293 cells. Furthermore, the insulin-stimulated GLUT4 vesicle translocation and glucose uptake were defective in Hap1-/- adipocytes. Finally, sortilin mediated the interaction of HAP1 and GLUT4. CONCLUSIONS: Our study showed that HAP1 formed a protein complex with GLUT4 and sortilin, and played a critical role in insulin-stimulated GLUT4 translocation in adipocytes. Its downregulation may contribute to the pathogenesis of diabetes.

Merging catalyst-free synthesis and iodine catalysis: one-pot synthesis of dihydrofuropyrimidines and spirodihydrofuropyrimidine pyrazolones.

A new and efficient one-pot strategy combining catalyst-free synthesis and iodine catalysis has been developed for the synthesis of dihydrofuropyrimidines and spirodihydrofuropyrimidine pyrazolones. This approach affords products in moderate to high yields (up to 96%) with excellent diastereoselectivities (up to >25 : 1 dr). The reaction is simple to carry out and is metal-free.

Asymmetric synthesis of polysubstituted chiral chromans via an organocatalytic oxa-Michael-nitro-Michael domino reaction.

A catalytic asymmetric method for the synthesis of polysubstituted chromans via an oxa-Michael-nitro-Michael reaction has been developed. The squaramide-catalyzed domino reaction of 2-hydroxynitrostyrenes with trans-ß-nitroolefins produced chiral chromans with excellent enantioselectivities (up to 99% ee), diastereoselectivities (up to >20 : 1 dr), and moderate to good yields (up to 82%).