Structure–activity relationship and improved hydrolytic stability of pyrazole derivatives that are allosteric inhibitors of West Nile Virus NS2B-NS3 proteinase

West Nile Virus (WNV) is a potentially deadly mosquito-borne flavivirus which has spread rapidly throughout the world. Currently there is no effective vaccine against flaviviral infections. We previously reported the identification of pyrazole ester derivatives as allosteric inhibitors of WNV NS2B-NS3 proteinase. These compounds degrade rapidly in pH 8 buffer with a half life of 1–2 h. We now report the design, synthesis and in vitro evaluation of pyrazole derivatives that are inhibitors of WNV NS2B-NS3 proteinase with greatly improved stability in the assay medium.     

Comparison of Post-Mine Rehabilitated and Natural Shrubland Communities in Southwestern Australia

Following mineral sand mining near Eneabba, southwestern Australia, rehabilitation managers have the difficult task of restoring shrubland communities of exceptional plant species richness. Species diversity, composition, structure, and key functional attributes in four mined sites rehabilitated 8 (R8) to 24 (R24) years ago were compared with those of typical nearby natural areas classified on the basis of substrate type (Low and High sand Dunes, shallow sand Swales, sand over Laterite, and sand over Limestone). The rehabilitated sites (except R8) had more species (about 140) than natural sites (about 100) in 40 × 40–m plots, with 12–37% species in common with natural sites. Rehabilitated sites were more similar in composition to each other than they were to the natural sites, with two strong colonizers, the fire-killed Acacia blakelyi and the fire-tolerant Melaleuca leuropoma , universally present. Dendrograms and ordinations based on composition and cover showed that rehabilitated sites grouped with each other before they did with the Dune and Swale sites (physically closest), and last with the Laterite and Limestone sites. Plant densities for R16 and R24 were about half those of the High Dune and Limestone, and about a quarter those of the Swale and Laterite. Fire resprouters were under-represented in the rehabilitated sites. Growth form distribution in rehabilitated sites was most similar to those of the dunes, with some woody shrubs up to 2.5 m tall present. Total iron and soil hardness (penetrability) were the only soil factors consistently different (higher) in the rehabilitated sites.     

Tetra- and Penta-Acylated Lipid A Structures of Porphyromonas gingivalis LPS Differentially Activate TLR4-Mediated NF-κB Signal Transduction Cascade and Immuno-Inflammatory Response in Human Gingival Fibroblasts

Background

Porphyromonas gingivalis is a major pathogen of periodontal disease that affects a majority of adults worldwide. Increasing evidence shows that periodontal disease is linked to various systemic diseases like diabetes and cardiovascular disease, by contributing to increased systemic levels of inflammation. Lipopolysaccharides (LPS), as a key virulent attribute of P. gingivalis, possesses significant amount of lipid A heterogeneity containing tetra- (LPS_1435/1449) and penta-acylated (LPS₁₆₉₀) structures. Hitherto, the exact molecular mechanism of P. gingivalis LPS involved in periodontal pathogenesis remains unclear, due to limited understanding of the specific receptors and signaling pathways involved in LPS-host cell interactions.

Methodology/Principal Findings

This study systematically investigated the effects of P. gingivalis LPS_1435/1449 and LPS₁₆₉₀ on the expression of TLR2 and TLR4 signal transduction and the activation of pro-inflammatory cytokines IL-6 and IL-8 in human gingival fibroblasts (HGFs). We found that LPS_1435/1449 and LPS₁₆₉₀ differentially modulated TLR2 and TLR4 expression. NF-κB pathway was significantly activated by LPS₁₆₉₀ but not by LPS_1435/1449. In addition, LPS₁₆₉₀ induced significant expression of NF-κB and p38 MPAK pathways-related genes, such as NFKBIA, NFKB1, IKBKB, MAP2K4 and MAPK8. Notably, the pro-inflammatory genes including GM-CSF, CXCL10, G-CSF, IL-6, IL-8 and CCL2 were significantly upregulated by LPS₁₆₉₀ while down-regulated by LPS_1435/1449. Blocking assays confirmed that TLR4-mediated NF-κB signaling was vital in LPS₁₆₉₀-induced expression of IL-6 and IL-8 in HGFs.

Conclusions/Significance

The present study suggests that the tetra- and penta-acylated lipid A structures of P. gingivalis LPS differentially activate TLR4-mediated NF-κB signaling pathway, and significantly modulate the expression of IL-6 and IL-8 in HGFs. The ability to alter the lipid A structure of LPS could be one of the strategies carried-out by P. gingivalis to evade innate host defense in gingival tissues, thereby contributing to periodontal pathogenesis.     

Equilibration of H labeling between body water and free amino acids: Enabling studies of proteome synthesis

Protein synthesis can be estimated by measuring the incorporation of a labeled amino acid into a proteolytic peptide. Although prelabeled amino acids are typically administered, recent studies have tested ²H₂O; the assumption is that there is rapid equilibration of ²H (in body water) with the carbon-bound hydrogens of amino acids before those amino acids are incorporated into a protein(s). We have determined the temporal changes in ²H labeling of body water and amino acids which should build confidence in ²H₂O-based studies of protein synthesis when one aims to measure the ²H labeling of proteolytic peptides.     

Equilibration of (2)H labeling between body water and free amino acids: enabling studies of proteome synthesis

Protein synthesis can be estimated by measuring the incorporation of a labeled amino acid into a proteolytic peptide. Although prelabeled amino acids are typically administered, recent studies have tested (2)H(2)O; the assumption is that there is rapid equilibration of (2)H (in body water) with the carbon-bound hydrogens of amino acids before those amino acids are incorporated into a protein(s). We have determined the temporal changes in (2)H labeling of body water and amino acids which should build confidence in (2)H(2)O-based studies of protein synthesis when one aims to measure the (2)H labeling of proteolytic peptides.     

Quantification of Magnetically Induced Changes in ECM Local Apparent Stiffness

The stiffness of the extracellular matrix (ECM) is known to influence cell behavior. The ability to manipulate the stiffness of ECM has important implications in understanding how cells interact mechanically with their microenvironment. This article describes an approach to manipulating the stiffness ECM, whereby magnetic beads are embedded in the ECM through bioconjugation between the streptavidin-coated beads and the collagen fibers and then manipulated by an external magnetic field. It also reports both analytical results (obtained by formal modeling and numerical simulation) and statistically meaningful experimental results (obtained by atomic force microscopy) that demonstrate the effectiveness of this approach. These results clearly suggest the possibility of creating desired stiffness gradients in ECM in vitro to influence cell behavior.     

Selection on bristle length has the ability to drive the evolution of male abdominal appendages in the sepsid fly Themira biloba

Many exaggerated and novel traits are strongly influenced by sexual selection. Although sexual selection is a powerful evolutionary force, underlying genetic interactions can constrain evolutionary outcomes. The relative strength of selection vs. constraint has been a matter of debate for the evolution of male abdominal appendages in sepsid flies. These abdominal appendages are involved in courtship and mating, but their function has not been directly tested. We performed mate choice experiments to determine whether sexual selection acts on abdominal appendages in the sepsid Themira biloba. We tested whether appendage bristle length influenced successful insemination by surgically trimming the bristles. Females paired with males that had shortened bristles laid only unfertilized eggs, indicating that long bristles are necessary for successful insemination. We also tested whether the evolution of bristle length was constrained by phenotypic correlations with other traits. Analyses of phenotypic covariation indicated that bristle length was highly correlated with other abdominal appendage traits, but was not correlated with abdominal sternite size. Thus, abdominal appendages are not exaggerated traits like many sexual ornaments, but vary independently from body size. At the same time, strong correlations between bristle length and appendage length suggest that selection on bristle length is likely to result in a correlated increase in appendage length. Bristle length is under sexual selection in T. biloba and has the potential to evolve independently from abdomen size.     

Eph/Ephrin membrane proteins: a mammalian expression vector pTIg-BOS-Fc allowing rapid protein purification

There is an urgent need for high purity, single chain, fully functional Eph/ephrin membrane proteins. This report outlines the pTIg-BOS-Fc vector and purification approach resulting in rapid increased production of fully functional single chain extracellular proteins that were isolated with high purity and used in structure-function analysis and pre-clinical studies.