Amblyceps crassioris,a new sisoroid catfish from Odisha,India (Siluriformes: Amblycipitidae)

Amblyceps crassioris, a new species of amblycipitid catfish, is described from the Mahanadi River basin in Odisha, India. The new species can be distinguished from its congeners in having a combination of the following characters: a deeply forked caudal fin, centrally projecting hooks on proximal lepidotrichia of median caudal-fin rays absent, jaws equal in length, lateral line absent, body depth at anus 15.1%–19.5% standard length (SL), caudal peduncle depth 13.0%–18.3% SL, adipose-fin base length 21.1%–27.1% SL, eye diameter 7.35%–14.1% head length and 38 total vertebrae.     

Lysosomal membrane protein composition, acidic pH and sterol content are regulated via a light-dependent pathway in metazoan cells

In metazoans, lysosomes are characterized by a unique tubular morphology, acidic pH, and specific membrane protein (LAMP) and lipid (cholesterol) composition as well as a soluble protein (hydrolases) composition. Here we show that perturbation to the eye-color gene, light, results in impaired lysosomal acidification, sterol accumulation, altered endosomal morphology as well as compromised lysosomal degradation. We find that Drosophila homologue of Vps41, Light, regulates the fusion of a specific subset of biosynthetic carriers containing characteristic endolysosomal membrane proteins, LAMP1, V0-ATPase and the cholesterol transport protein, NPC1, with the endolysosomal system, and is then required for the morphological progression of the multivesicular endosome. Inhibition of Light results in accumulation of biosynthetic transport intermediates that contain these membrane cargoes, whereas under similar conditions, endosomal delivery of soluble hydrolases, previously shown to be mediated by Dor, the Drosophila homologue of Vps18, is not affected. Unlike Dor, Light is recruited to endosomes in a PI3P-sensitive fashion wherein it facilitates fusion of these biosynthetic cargoes with the endosomes. Depletion of the mammalian counterpart of Light, hVps41, in a human cell line also inhibits delivery of hLAMP to endosomes, suggesting an evolutionarily conserved pathway in metazoa.     

Islet-like cell aggregates generated from human adipose tissue derived stem cells ameliorate experimental diabetes in mice

Background

Type 1 Diabetes Mellitus is caused by auto immune destruction of insulin producing beta cells in the pancreas. Currently available treatments include transplantation of isolated islets from donor pancreas to the patient. However, this method is limited by inadequate means of immuno-suppression to prevent islet rejection and importantly, limited supply of islets for transplantation. Autologous adult stem cells are now considered for cell replacement therapy in diabetes as it has the potential to generate neo-islets which are genetically part of the treated individual. Adopting methods of islet encapsulation in immuno-isolatory devices would eliminate the need for immuno-suppressants.

Methodology/Principal Findings

In the present study we explore the potential of human adipose tissue derived adult stem cells (h-ASCs) to differentiate into functional islet like cell aggregates (ICAs). Our stage specific differentiation protocol permit the conversion of mesodermic h-ASCs to definitive endoderm (Hnf3β, TCF2 and Sox17) and to PDX1, Ngn3, NeuroD, Pax4 positive pancreatic endoderm which further matures in vitro to secrete insulin. These ICAs are shown to produce human C-peptide in a glucose dependent manner exhibiting in-vitro functionality. Transplantation of mature ICAs, packed in immuno-isolatory biocompatible capsules to STZ induced diabetic mice restored near normoglycemia within 3–4 weeks. The detection of human C-peptide, 1155±165 pM in blood serum of experimental mice demonstrate the efficacy of our differentiation approach.

Conclusions

h-ASC is an ideal population of personal stem cells for cell replacement therapy, given that they are abundant, easily available and autologous in origin. Our findings present evidence that h-ASCs could be induced to differentiate into physiologically competent functional islet like cell aggregates, which may provide as a source of alternative islets for cell replacement therapy in type 1 diabetes.     

Cation-Mediated Interplay of Loops in Chaperonin-10

Abstract

The ubiquitously occurring chaperonins consist of a large tetradecameric Chaperonin-60, forming a cylindrical assembly, and a smaller heptameric Chaperonin-10. For a functional protein folding cycle, Chaperonin-10 caps the cylindrical Chaperonin-60 from one end forming an asymmetric complex. The oligomeric assembly of Chaperonin-10 is known to be highly plastic in nature. In Mycobacterium tuberculosis, the plasticity has been shown to be modulated by reversible binding of divalent cations. Binding of cations confers rigidity to the metal binding loop, and also promotes stability of the oligomeric structure. We have probed the conformational effects of cation binding on the Chaperonin-10 structure through fluorescence studies and molecular dynamics simulations. Fluorescence studies show that cation binding induces reduced exposure and flexibility of the dome loop. The simulations corroborate these results and further indicate a complex landscape of correlated motions between different parts of the molecule. They also show a fascinating interplay between two distantly spaced loops, the metal binding “dome loop” and the GroEL-binding “mobile loop”, suggesting an important cation-mediated role in the recognition of Chaperonin-60. In the presence of cations the mobile loop appears poised to dock onto the Chaperonin-60 structure. The divalent metal ions may thus act as key elements in the protein folding cycle, and trigger a conformational switch for molecular recognition.     

Virulence targeted inhibitory effect of linalool against the exclusive uropathogen Proteus mirabilis

Proteus mirabilis is one of the leading causes of catheter-associated UTIs (CAUTI) in individuals with prolonged urinary catheterization. Since, biofilm assisted antibiotic resistance is reported to complicate the treatment strategies of P. mirabilis infections, the present study was aimed to attenuate biofilm and virulence factor production in P. mirabilis. Linalool is a naturally occurring monoterpene alcohol found in a wide range of flowers and spice plants and has many biological applications. In this study, linalool exhibited concentration dependent anti-biofilm activity against crystalline biofilm of P. mirabilis through reduced production of the virulence enzyme urease that raises the urinary pH and drives the formation of crystals (struvite) in the biofilm. The results of q-PCR analysis unveiled the down regulation of biofilm/virulence associated genes upon linalool treatment, which was in correspondence with the in vitro bioassays. Thus, this study reports the feasibility of linalool acting as a promising anti-biofilm agent against P. mirabilis mediated CAUTI.     

Breast Tumors with Elevated Expression of 1q Candidate Genes Confer Poor Clinical Outcome and Sensitivity to Ras/PI3K Inhibition

Genomic aberrations are common in cancers and the long arm of chromosome 1 is known for its frequent amplifications in breast cancer. However, the key candidate genes of 1q, and their contribution in breast cancer pathogenesis remain unexplored. We have analyzed the gene expression profiles of 1635 breast tumor samples using meta-analysis based approach and identified clinically significant candidates from chromosome 1q. Seven candidate genes including exonuclease 1 (EXO1) are consistently over expressed in breast tumors, specifically in high grade and aggressive breast tumors with poor clinical outcome. We derived a EXO1 co-expression module from the mRNA profiles of breast tumors which comprises 1q candidate genes and their co-expressed genes. By integrative functional genomics investigation, we identified the involvement of EGFR, RAS, PI3K / AKT, MYC, E2F signaling in the regulation of these selected 1q genes in breast tumors and breast cancer cell lines. Expression of EXO1 module was found as indicative of elevated cell proliferation, genomic instability, activated RAS/AKT/MYC/E2F1 signaling pathways and loss of p53 activity in breast tumors. mRNA–drug connectivity analysis indicates inhibition of RAS/PI3K as a possible targeted therapeutic approach for the patients with activated EXO1 module in breast tumors. Thus, we identified seven 1q candidate genes strongly associated with the poor survival of breast cancer patients and identified the possibility of targeting them with EGFR/RAS/PI3K inhibitors.     

Molecular docking of azole drugs and their analogs on CYP121 of Mycobacterium tuberculosis

The Mycobacterium tuberculosis genome codes for 20 different cytochromes. These cytochromes are involved in the breakdown of recalcitrant pollutants and the synthesis of polyketide antibiotics and other complex macromolecules. It has been demonstrated that CYP121 is essential for viability of the bacterium by gene knock-out and complementation studies. CYP121 could therefore be a probable target for the development of new drugs for TB. It has been widely reported that orthologs of CYP121 in fungi are inhibited by azole drugs. We evaluated whether these azole drugs or their structural analogs could bind to and inhibit CYP121 of M. tuberculosis using molecular docking. Six molecules with known anti-CYP121 activity were selected from literature and PubChem database was searched to identify structural analogs for these inhibitors. Three hundred and fifty seven molecules were identified as structural analogs and used in docking studies. Fifty three molecules were found to be scored better than the azole drugs and five of them were ranked among the top 12 molecules by two different scoring functions. These molecules may be further tested by in vitro experimentation for their activity against CYP121 of M. tuberculosis.     

Metabolic engineering of soybean affords improved phytosterol seed traits

Different combinations of three rate‐limiting enzymes in phytosterol biosynthesis, the Arabidopsis thaliana hydroxyl methylglutaryl CoA1 (HMGR1) catalytic subunit linked to either constitutive or seed‐specific β‐conglycinin promoter, and the Glycine max sterol methyltransferase1 (SMT1) and sterol methyltransferase2‐2 (SMT2‐2) genes, under the control of seed‐specific Glycinin‐1 and Beta‐phaseolin promoters, respectively, were engineered in soybean plants. Mature seeds of transgenic plants displayed modest increases in total sterol content, which points towards a tight control of phytosterol biosynthesis. However, in contrast to wild‐type seeds that accumulated about 35% of the total sterol in the form of intermediates, in the engineered seeds driven by a seed‐specific promoter, metabolic flux was directed to Δ⁵‐24‐alkyl sterol formation (99% of total sterol). The engineered effect of end‐product sterol (sitosterol, campesterol, and stigmasterol) over‐production in soybean seeds resulted in an approximately 30% increase in overall sitosterol synthesis, a desirable trait for oilseeds and human health. In contradistinction, increased accumulation of cycloartenol and 24(28)‐methylencylartanol (55% of the total sterol) was detected in plants harbouring the constitutive t‐HMGR1 gene, consistent with the previous studies. Our results support the possibility that metabolic flux of the phytosterol family pathway is differentially regulated in leaves and seeds.     

The diabetes susceptibility locus Idd5.1 on mouse chromosome 1 regulates ICOS expression and modulates murine experimental autoimmune encephalomyelitis

Linkage analysis and congenic mapping in NOD mice have identified a susceptibility locus for type 1 diabetes, Idd5.1 on mouse chromosome 1, which includes the Ctla4 and Icos genes. Besides type 1 diabetes, numerous autoimmune diseases have been mapped to a syntenic region on human chromosome 2q33. In this study we determined how the costimulatory molecules encoded by these genes contribute to the immunopathogenesis of experimental autoimmune encephalomyelitis (EAE). When we compared levels of expression of costimulatory molecules on T cells, we found higher ICOS and lower full-length CTLA-4 expression on activated NOD T cells compared with C57BL/6 (B6) and C57BL/10 (B10) T cells. Using NOD.B10 Idd5 congenic strains, we determined that a 2.1-Mb region controls the observed expression differences of ICOS. Although Idd5.1 congenic mice are resistant to diabetes, we found them more susceptible to myelin oligodendrocyte glycoprotein 35-55-induced EAE compared with NOD mice. Our data demonstrate that higher ICOS expression correlates with more IL-10 production by NOD-derived T cells, and this may be responsible for the less severe EAE in NOD mice compared with Idd5.1 congenic mice. Paradoxically, alleles at the Idd5.1 locus have opposite effects on two autoimmune diseases, diabetes and EAE. This may reflect differential roles for costimulatory pathways in inducing autoimmune responses depending upon the origin (tissue) of the target Ag.