Sequence analysis of a salt tolerant metagenomic clone

Metagenome represent an unlimited resource for discovery of novel genes. Here we report, sequence analysis of a salt tolerant metagenomic clone (6B4) from a pond water metagenomic library. Clone 6B4 had an insert of 2254 bp with G+C composition of 64.06%. DNA sequence from 6B4 showed homology to DNA sequences from pro-teobacteria indicating origin of 6B4 metagenomic insert from a yet uncharacterized proteobacteria. Two encoded proteins from clone 6B4 showed match with ATP-depen-dent Clp protease adaptor protein (ClpS) and phasin, while two truncated encoded proteins showed match with poly-3-hydroxybutyrate synthase and permease. Clp complex is known to play a role in stress tolerance. Expression of ClpS from metagenomic clone is proposed to be responsible for salt tolerance of the metagenomic clone 6B4.     

Synthetic riboswitches that induce gene expression in diverse bacterial species

We developed a series of ligand-inducible riboswitches that control gene expression in diverse species of Gram-negative and Gram-positive bacteria, including human pathogens that have few or no previously reported inducible expression systems. We anticipate that these riboswitches will be useful tools for genetic studies in a wide range of bacteria.     

6-(4′-Aryloxy-phenyl)vinyl-1,2,4-trioxanes: A new series of orally active peroxides effective against multidrug-resistant Plasmodium yoelii in Swiss mice

A new series of 6-(4′-aryloxy-phenyl)vinyl-1,2,4-trioxanes 10a–d, 11a–d, and 12a–d have been synthesized and evaluated for their antimalarial activity against multidrug-resistant Plasmodium yoelii in Swiss mice by oral route. Trioxanes 10b and 10c, the two most active compounds of the series, provided 100% protection to the infected mice at 48 mg/kg × 4 days. Clinically useful drug β-arteether provided 100% and 20% protection at 48 mg/kg × 4 days and 24 mg/kg × 4 days, respectively, in this model.     

Ternary SNARE complexes are enriched in lipid rafts during mast cell exocytosis

Lipid rafts are membrane microdomains rich in cholesterol and glycosphingolipids that have been implicated in the regulation of intracellular protein trafficking. During exocytosis, a class of proteins termed SNAREs mediate secretory granule-plasma membrane fusion. To investigate the role of lipid rafts in secretory granule exocytosis, we examined the raft association of SNARE proteins and SNARE complexes in rat basophilic leukemia (RBL) mast cells. The SNARE protein SNAP-23 co-localized with a lipid raft marker and was present in detergent-insoluble lipid raft microdomains in RBL cells. By contrast, only small amounts (<20%) of the plasma membrane SNARE syntaxin 4 or the granule-associated SNARE vesicle-associated membrane protein (VAMP)-2 were present in these microdomains. Despite this, essentially all syntaxin 4 and most of VAMP-2 in these rafts were present in SNARE complexes containing SNAP-23, while essentially none of these complexes were present in nonraft membranes. Whereas SNAP-23 is membrane anchored by palmitoylation, the association of the transmembrane protein syntaxin 4 with lipid rafts was because of its binding to SNAP-23. After stimulating mast cells exocytosis, the amount of syntaxin 4 and VAMP-2 present in rafts increased twofold, and these proteins were now present in raft-associated phospho-SNAP-23/syntaxin 4/VAMP-2 complexes, revealing differential association of SNARE fusion complexes during the process of regulated exocytosis.     

Secondary penile tumours revisited

Objective

To highlight the salient features of metastatic malignancies involving the penis, with special reference to the primary tumour sites, metastatic mechanisms, clinical features, differential diagnosis, treatment and prognosis.

Methods

A comprehensive search of the literature was performed using MEDLINE and EMBASE, using the keywords 'penis', 'secondary malignancy', 'metastasis' and 'malignant priapism' to identify reviews and case reports of secondary penile malignancy. A case of rare clinical presentation of metastatic penile lesion is presented along with the review of the literature.

Conclusion

Secondary malignancy of the penis is a rare clinical entity, despite the rich vascularisation of this organ. The majority of metastatic lesions take their origin from the neighbouring genito-urinary organs, mainly prostate and bladder. These lesions are often associated with disseminated malignancy and hence have a poor outcome. Nodular or ulcerative lesions involving the corpora cavernosa or priapism are the main modes of clinical presentation. In most cases, only palliative or supportive therapy is indicated.

     

IL-13 signaling through the IL-13alpha2 receptor is involved in induction of TGF-beta1 production and fibrosis

Interleukin (IL)-13 is a major inducer of fibrosis in many chronic infectious and autoimmune diseases. In studies of the mechanisms underlying such induction, we found that IL-13 induces transforming growth factor (TGF)-beta(1) in macrophages through a two-stage process involving, first, the induction of a receptor formerly considered to function only as a decoy receptor, IL-13Ralpha(2). Such induction requires IL-13 (or IL-4) and tumor necrosis factor (TNF)-alpha. Second, it involves IL-13 signaling through IL-13Ralpha(2) to activate an AP-1 variant containing c-jun and Fra-2, which then activates the TGFB1 promoter. In vivo, we found that prevention of IL-13Ralpha(2) expression reduced production of TGF-beta(1) in oxazolone-induced colitis and that prevention of IL-13Ralpha(2) expression, Il13ra2 gene silencing or blockade of IL-13Ralpha(2) signaling led to marked downregulation of TGF-beta(1) production and collagen deposition in bleomycin-induced lung fibrosis. These data suggest that IL-13Ralpha(2) signaling during prolonged inflammation is an important therapeutic target for the prevention of TGF-beta(1)-mediated fibrosis.     

The MicroArray Quality Control (MAQC) project shows inter- and intraplatform reproducibility of gene expression measurements

Over the last decade, the introduction of microarray technology has had a profound impact on gene expression research. The publication of studies with dissimilar or altogether contradictory results, obtained using different microarray platforms to analyze identical RNA samples, has raised concerns about the reliability of this technology. The MicroArray Quality Control (MAQC) project was initiated to address these concerns, as well as other performance and data analysis issues. Expression data on four titration pools from two distinct reference RNA samples were generated at multiple test sites using a variety of microarray-based and alternative technology platforms. Here we describe the experimental design and probe mapping efforts behind the MAQC project. We show intraplatform consistency across test sites as well as a high level of interplatform concordance in terms of genes identified as differentially expressed. This study provides a resource that represents an important first step toward establishing a framework for the use of microarrays in clinical and regulatory settings.