Infection of human amniotic and endothelial cells by Japanese encephalitis virus: Increased expression of HLA-F

Productive infection of human amniotic and endothelial cell lines with Japanese encephalitis virus (JEV) was established leading to the induction of NF kappa B and HLA-F, a non-classical MHC molecule. Induction of the HLA-F gene and protein in JEV-infected cells was shown to be NF kappa B dependent since it was blocked by inhibitors of NF kappa B activation. ShRNA targeting lentivirus-mediated stable knockdown of the p65 subunit of NF kappa B inhibited JEV-mediated induction of HLA-F both in the amniotic cell line, AV-3 as well as the human brain microendothelial cell line, HBMEC. The induction of HLA-F by treatment of AV-3 with TNF-alpha was also inhibited by ShRNA mediated knockdown of NF kappa B. TNF-alpha treatment of HEK293T cells that were transfected with reporter plasmids under the control of HLA-F enhancer A elements resulted in significant transactivation of the luciferase reporter gene. NF kappa B-mediated induction of HLA-F following JEV infection and TNF-alpha exposure is being suggested for the first time. (C) 2014 Elsevier Inc. All rights reserved.

An Expeditious Asymmetric Synthesis of the Polyketide Unit Present in HIV-Inhibitory Depsipeptides Aetheramide A and B

The enantioselective synthesis of the polyketide unit present in depsipeptides aetheramide A and B, which possess potent HIV-inhibitory activity, is accomplished from a chiral furyl carbinol.

Selective growth of single phase VO2(A, B, and M) polymorph thin films

We demonstrate the growth of high quality single phase films of VO2(A, B, and M) on SrTiO3 substrate by controlling the vanadium arrival rate (laser frequency) and oxidation of the V atoms. A phase diagram has been developed (oxygen pressure versus laser frequency) for various phases of VO2 and their electronic properties are investigated. VO2(A) phase is insulating VO2(B) phase is semi-metallic, and VO2(M) phase exhibits a metal-insulator transition, corroborated by photoelectron spectroscopic studies. The ability to control the growth of various polymorphs opens up the possibility for novel (hetero) structures promising new device functionalities. (C) 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.

Analysis of the hierarchical structure of the B. subtilis transcriptional regulatory network

The transcriptional regulation of gene expression is orchestrated by complex networks of interacting genes. Increasing evidence indicates that these `transcriptional regulatory networks' (TRNs) in bacteria have an inherently hierarchical architecture, although the design principles and the specific advantages offered by this type of organization have not yet been fully elucidated. In this study, we focussed on the hierarchical structure of the TRN of the gram-positive bacterium Bacillus subtilis and performed a comparative analysis with the TRN of the gram-negative bacterium Escherichia coli. Using a graph-theoretic approach, we organized the transcription factors (TFs) and sigma-factors in the TRNs of B. subtilis and E. coli into three hierarchical levels (Top, Middle and Bottom) and studied several structural and functional properties across them. In addition to many similarities, we found also specific differences, explaining the majority of them with variations in the distribution of s-factors across the hierarchical levels in the two organisms. We then investigated the control of target metabolic genes by transcriptional regulators to characterize the differential regulation of three distinct metabolic subsystems (catabolism, anabolism and central energy metabolism). These results suggest that the hierarchical architecture that we observed in B. subtilis represents an effective organization of its TRN to achieve flexibility in response to a wide range of diverse stimuli.

Al3+-Ion-Triggered Conformational Isomerization of a Rhodamine B Derivative Evidenced by a Fluorescence Signal - A Crystallographic Proof

A newly designed rhodamine B anisaldehyde hydrazone exhibits Al3+-ion-induced cis (L) to trans (L) conformational isomerization with respect to the xanthene moiety through a rotation about a N-N bond; the isomerization is indicated by a detectable naked-eye color change and a turn-on red fluorescence in 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) buffer (EtOH/Water 1:9 v/v; pH 7.4) at 25 degrees C. In support of this observation, detailed spectroscopic and physicochemical studies along with density function theory (DFT) calculations have been performed. This cis-to-trans conformational isomerization is due to Al3+ ion coordination, which induces this visual color change and the turn-on fluorescence response. To strengthen our knowledge of the conformational isomerization, detailed structural characterizations of the cis and trans isomers in the solid state were performed by single-crystal X-ray diffraction. To the best of our knowledge, this is the first structural report of both cis and trans conformational isomers for this family of compounds. Moreover, this noncytotoxic probe could be used to image the accumulation of Al3+ ions in HeLa and MCF-7 cell lines.

B-Spline potential function for maximum a-posteriori image reconstruction in fluorescence microscopy

An iterative image reconstruction technique employing B-Spline potential function in a Bayesian framework is proposed for fluorescence microscopy images. B-splines are piecewise polynomials with smooth transition, compact support and are the shortest polynomial splines. Incorporation of the B-spline potential function in the maximum-a-posteriori reconstruction technique resulted in improved contrast, enhanced resolution and substantial background reduction. The proposed technique is validated on simulated data as well as on the images acquired from fluorescence microscopes (widefield, confocal laser scanning fluorescence and super-resolution 4Pi microscopy). A comparative study of the proposed technique with the state-of-art maximum likelihood (ML) and maximum-a-posteriori (MAP) with quadratic potential function shows its superiority over the others. B-Spline MAP technique can find applications in several imaging modalities of fluorescence microscopy like selective plane illumination microscopy, localization microscopy and STED. (C) 2015 Author(s).

Significant photocytotoxic effect of an iron(III) complex of a Schiff base ligand derived from vitamin B-6 and thiosemicarbazide in visible light

Iron(III)-Schiff base complexes, namely, Fe(tsc-py)(2)](NO3) (1), Fe(tsc-acpy)(2)](NO3) (2) and Fe(tsc-VB6)(2)](NO3) (3), where tsc-py, tsc-acpy and tsc-VB6 are the respective Schiff bases derived from thiosemicarbazide (tsc) and pyridine-2-aldehyde (tsc-py), 2-acetyl pyridine (tsc-acpy) and vitamin B-6 (pyridoxal, tsc-VB6), have been prepared, structurally characterized and their photocytotoxicity studied in cancer HeLa cells. The single crystal X-ray structures of the complexes 1 and 2 show a distorted octahedral geometry formed by the FeN4S2 core. The low-spin and 1 : 1 electrolytic complexes display a broad absorption band in the visible region. Complexes 1 and 2, without any VB6 moiety are not cytotoxic under light or dark conditions. Complex 3 is significantly photocytotoxic under visible light of 400-700 nm giving an IC50 value of 22.5 mu M in HeLa cells with no dark toxicity (IC50 > 100 mu M). The photo-induced cell death is attributable to apoptotic pathways involving photo-assisted generation of intracellular ROS. The observed photocytotoxicity of complex 3 could be the result of its better photosensitizing property combined with its enhanced uptake into cancer cells via a VB6 transporting membrane carrier (VTC) mediated diffusion pathway due to the presence of the VB6 moiety compared to the two non-vitamin B-6 analogues, complexes 1 and 2.

DNA intercalative 4-butylaminopyrimido4',5':4,5]thieno(2,3-b)quinoline induces cell cycle arrest and apoptosis in leukemia cells

DNA intercalators are one of the interesting groups in cancer chemotherapy. The development of novel anticancer small molecule has gained remarkable interest over the last decade. In this study, we synthesized and investigated the ability of a tetracyclic-condensed quinoline compound, 4-butylaminopyrimido4',5':4,5]thieno(2,3-b)quinoline (BPTQ), to interact with double-stranded DNA and inhibit cancer cell proliferation. Circular dichroism, topological studies, molecular docking, absorbance, and fluorescence spectral titrations were employed to study the interaction of BPTQ with DNA. Cytotoxicity was studied by performing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assay. Further, cell cycle analysis by flow cytometry, annexin V staining, mitochondrial membrane potential assay, DNA fragmentation, and western blot analysis were used to elucidate the mechanism of action of BPTQ at the cellular level. Spectral, topological, and docking studies confirmed that BPTQ is a typical intercalator of DNA. BPTQ induces dose-dependent inhibitory effect on the proliferation of cancer cells by arresting cells at S and G2/M phase. Further, BPTQ activates the mitochondria-mediated apoptosis pathway, as explicated by a decrease in mitochondrial membrane potential, increase in the Bax:Bcl-2 ratio, and activation of caspases. These results confirmed that BPTQ is a DNA intercalative anticancer molecule, which could aid in the development of future cancer therapeutic agents.

Dynamic compression behavior of reactive spark plasma sintered ultrafine grained (Hf, Zr)B-2-SiC composites

This paper reports the dynamic compression behavior of ultrafine grained (Hf, Zr)B-2-SiC composites, sintered using reactive spark plasma sintering at 1600 degrees C for 10 min. Dynamic strength of similar to 2.3 GPa has been measured using Split Hopkinson Pressure Bar (SHPB) tests in a reproducible manner at strain rates of 800-1300 s(-1). A comparison with competing boride based armor ceramics, in reference to the spectrum of properties evaluated, establishes the potential of (Hf, Zr)B-2-SiC composites for armor applications. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

A novel DNA intercalator, 8-methoxy pyrimido4 `,5 `:4,5]thieno (2,3-b)quinoline-4(3H)-one induces apoptosis in cancer cells, inhibits the tumor progression and enhances lifespan in mice with tumor

Polycyclic aromatic molecules such as ellipticine intercalate into double-stranded DNA and interfere with physiological functions. In the present study, we evaluate the chemotherapeutic potential of MPTQ on animal models and its mode of action. In order to test the antitumor activity, monohydrochloride of MPTQ was orally administered in mice bearing tumor. Results showed a significant inhibition of tumor growth compared to that of untreated controls. More importantly, mean lifespan of tumor bearing animals treated with MPTQ was significantly higher as compared to that of untreated tumor bearing mice suggesting that the treatment affected viability of cancerous cells, but not of normal cells. Consistent with this, we find that administration of MPTQ to normal mice did not cause any major side effects as observed upon hematological and serum profiling. We also found that MPTQ induces cytotoxicity in cancer cell lines, by activating apoptosis both by intrinsic and extrinsic pathways. Thus, MPTQ could be used as a potential cancer therapeutic agent. (c) 2011 Wiley Periodicals, Inc.

Structure of an amidohydrolase, SACOL0085, from methicillin-resistant Staphylococcus aureus COL

Staphylococcus aureus is an opportunistic pathogen that rapidly acquires resistance to frontline antibiotics. The characterization of novel protein targets from this bacterium is thus an important step towards future therapeutic strategies. Here, the crystal structure of an amidohydrolase, SACOL0085, from S. aureus COL is described. SACOL0085 is a member of the M20D family of peptidases. Unlike other M20D peptidases, which are either monomers or dimers, SACOL0085 adopts a butterfly-shaped homotetrameric arrangement with extensive intersubunit interactions. Each subunit of SACOL0085 contains two Mn2+ ions at the active site. A conserved cysteine residue at the active site distinguishes M20D peptidases from other M20 family members. This cysteine, Cys103, serves as bidentate ligand coordinating both Mn2+ ions in SACOL0085.

Modelling staphylococcal pneumonia in a human 3D lung tissue model system delineates toxin-mediated pathology

Staphylococcus aureus necrotizing pneumonia is recognized as a toxin-mediated disease, yet the tissue-destructive events remain elusive, partly as a result of lack of mechanistic studies in human lung tissue. In this study, a three-dimensional (3D) tissue model composed of human lung epithelial cells and fibroblasts was used to delineate the role of specific staphylococcal exotoxins in tissue pathology associated with severe pneumonia. To this end, the models were exposed to the mixture of exotoxins produced by S. aureus strains isolated from patients with varying severity of lung infection, namely necrotizing pneumonia or lung empyema, or to purified toxins. The necrotizing pneumonia strains secreted high levels of alpha-toxin and Panton-Valentine leukocidin (PVL), and triggered high cytotoxicity, inflammation, necrosis and loss of E-cadherin from the lung epithelium. In contrast, the lung empyema strain produced moderate levels of PVL, but negligible amounts of alpha-toxin, and triggered limited tissue damage. alpha-toxin had a direct damaging effect on the epithelium, as verified using toxin-deficient mutants and pure alpha-toxin. Moreover, PVL contributed to pathology through the lysis of neutrophils. A combination of alpha-toxin and PVL resulted in the most severe epithelial injury. In addition, toxin-induced release of pro-inflammatory mediators from lung tissue models resulted in enhanced neutrophil migration. Using a collection of 31 strains from patients with staphylococcal pneumonia revealed that strains producing high levels of alpha-toxin and PVL were cytotoxic and associated with fatal outcome. Also, the strains that produced the highest toxin levels induced significantly greater epithelial disruption. Of importance, toxin-mediated lung epithelium destruction could be inhibited by polyspecific intravenous immunoglobulin containing antibodies against alpha-toxin and PVL. This study introduces a novel model system for study of staphylococcal pneumonia in a human setting. The results reveal that the combination and levels of alpha-toxin and PVL correlate with tissue pathology and clinical outcome associated with pneumonia.

On the contributions of different micromechanisms for enhancement in the strength of TI-6Al-4V alloy upon B addition: A nanomechanical analysis

The addition of small amount of boron to Ti and it alloys refines the as-cast microstructure and enhances the mechanical properties. In this paper, we employ nanoindentation on each of the constituent phases in the microstructure and `rule-of-mixture' type analysis to examine their relative contributions to the strength enhancement in a Ti-6Al-4V alloy modified with 0.3 wt% B. Our results indicate to two main contributors to the relatively higher flow strength of B-modified alloy vis-a-vis the base alloy: (a) strengthening of alpha phase due to the reduction in the effective slip length that occurs as a result of the microstructural refinement that occurs upon B addition, and (b) composite strengthening caused by the TiB whiskers present in the alloy. (C) 2015 Elsevier B.V. All rights reserved.

Roles for Transcription Factors Sp1, NF-kappa B, IRF3, and IRF7 in Expression of the Human IFNL4 Gene

The expression of a biologically active human IFN4 depends on the presence of a frameshift deletion polymorphism within the first exon of the interferon lambda 4 (IFNL4) gene. In this report, we use the lung carcinoma-derived cell line, A549, which is genetically viable to express a functional IFN4, to address transcriptional requirements of the IFNL4 gene. We show that the GC-rich DNA-binding transcription factor (TF) specificity protein 1 (Sp1) is recruited to the IFNL4 promoter and has a role in induction of gene expression upon stimulation with viral RNA mimic poly(I:C). By using RNAi and overexpression strategies, we also show key roles in IFNL4 gene expression for the virus-inducible TFs, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-B), IFN regulatory factor 3 (IRF3), and IRF7. Interestingly, we also observe that overexpression of IFN4 influences IFNL4 promoter activity, which may further be dependent on the retinoic acid-inducible gene-I (RIG-I)-like receptor pathway. Together, our work for the first time reports on the functional characterization of the human IFNL4 promoter.