1,402 research outputs found

    Effects of hydrogen bond and solvent polarity on the C=O strectching of bis(2-thienyl)ketone in solution

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    The optimized structural parameters, the absorption and the resonance Raman spectra have been investigated for the bis(2-thienyl)ketone in gas phase, in cyclohexane, methanol, and acetonitrile solvents by means of time dependent density functional theory calculations, the solvent electronic polarization effect on the solvation shift is examined and in well accordance with the calculation. The effect of increasing the polarity of the solvent is well represented by the polarizable continuum model, both for the absorption spectra and resonance Raman intensities. The Raman spectra of the C=O stretching mode, which is sensitive to the intermolecular interaction for bis(2-thienyl)ketone dissolved in solvents, were systematically studied. It was found that the hydrogen bond effect plays an important role in reducing the carbonyl stretching wavenumbers. The results of Raman shifts were interpreted through the dilution effect, solvation effects, and hydrogen bond-forming effects. Furthermore, the excitation profiles of several important Raman bands of bis(2-thienyl)ketone molecule in different solvents have been critically analyzed. The solvent effects on structural and symmetry properties of the molecule in S2 electronic state as well as the short-time photo relaxation dynamics have been discussed.published_or_final_versio

    Development of a high-throughput microsatellite typing approach for forensic and population genetic analysis of wild and domestic African Bovini.

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    Conservation management and forensic traceability of African buffalo and cattle rely on the timely provision of unbiased and accurate genetic information. An approach in which 17 cattle microsatellitemarkers are co-electrophoresed, following amplification in three core multiplex reactions was established for this purpose. Mean allelic richness per locus was 8.24 and 6.47, for buffalo and Bonsmara cattle, respectively, whilst an unbiased match probability of 6.5x10-17 and 1.03 x 10-16 wasobtained for each. These results confirm the usefulness of this rapid, cost-effective typing approach for forensic, paternity and fine-scale genetic analyses of wild and domestic African Bovini tribe members

    A repurposing strategy for Hsp90 inhibitors demonstrates their potency against filarial nematodes

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    Novel drugs are required for the elimination of infections caused by filarial worms, as most commonly used drugs largely target the microfilariae or first stage larvae of these infections. Previous studies, conducted in vitro, have shown that inhibition of Hsp90 kills adult Brugia pahangi. As numerous small molecule inhibitors of Hsp90 have been developed for use in cancer chemotherapy, we tested the activity of several novel Hsp90 inhibitors in a fluorescence polarization assay and against microfilariae and adult worms of Brugia in vitro. The results from all three assays correlated reasonably well and one particular compound, NVP-AUY922, was shown to be particularly active, inhibiting Mf output from female worms at concentrations as low as 5.0 nanomolar after 6 days exposure to drug. NVP-AUY922 was also active on adult worms after a short 24 h exposure to drug. Based on these in vitro data, NVP-AUY922 was tested in vivo in a mouse model and was shown to significantly reduce the recovery of both adult worms and microfilariae. These studies provide proof of principle that the repurposing of currently available Hsp90 inhibitors may have potential for the development of novel agents with macrofilaricidal properties

    The Adjuvanticity of an O. volvulus-Derived rOv-ASP-1 Protein in Mice Using Sequential Vaccinations and in Non-Human Primates

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    Adjuvants potentiate antigen-specific protective immune responses and can be key elements promoting vaccine effectiveness. We previously reported that the Onchocerca volvulus recombinant protein rOv-ASP-1 can induce activation and maturation of naïve human DCs and therefore could be used as an innate adjuvant to promote balanced Th1 and Th2 responses to bystander vaccine antigens in mice. With a few vaccine antigens, it also promoted a Th1-biased response based on pronounced induction of Th1-associated IgG2a and IgG2b antibody responses and the upregulated production of Th1 cytokines, including IL-2, IFN-γ, TNF-α and IL-6. However, because it is a protein, the rOv-ASP-1 adjuvant may also induce anti-self-antibodies. Therefore, it was important to verify that the host responses to self will not affect the adjuvanticity of rOv-ASP-1 when it is used in subsequent vaccinations with the same or different vaccine antigens. In this study, we have established rOv-ASP-1's adjuvanticity in mice during the course of two sequential vaccinations using two vaccine model systems: the receptor-binding domain (RBD) of SARS-CoV spike protein and a commercial influenza virus hemagglutinin (HA) vaccine comprised of three virus strains. Moreover, the adjuvanticity of rOv-ASP-1 was retained with an efficacy similar to that obtained when it was used for a first vaccination, even though a high level of anti-rOv-ASP-1 antibodies was present in the sera of mice before the administration of the second vaccine. To further demonstrate its utility as an adjuvant for human use, we also immunized non-human primates (NHPs) with RBD plus rOv-ASP-1 and showed that rOv-ASP-1 could induce high titres of functional and protective anti-RBD antibody responses in NHPs. Notably, the rOv-ASP-1 adjuvant did not induce high titer antibodies against self in NHPs. Thus, the present study provided a sound scientific foundation for future strategies in the development of this novel protein adjuvant

    Dynamics of Molecular Evolution and Phylogeography of Barley yellow dwarf virus-PAV

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    Barley yellow dwarf virus (BYDV) species PAV occurs frequently in irrigated wheat fields worldwide and can be efficiently transmitted by aphids. Isolates of BYDV-PAV from different countries show great divergence both in genomic sequences and pathogenicity. Despite its economical importance, the genetic structure of natural BYDV-PAV populations, as well as of the mechanisms maintaining its high diversity, remain poorly explored. In this study, we investigate the dynamics of BYDV-PAV genome evolution utilizing time-structured data sets of complete genomic sequences from 58 isolates from different hosts obtained worldwide. First, we observed that BYDV-PAV exhibits a high frequency of homologous recombination. Second, our analysis revealed that BYDV-PAV genome evolves under purifying selection and at a substitution rate similar to other RNA viruses (3.158×10−4 nucleotide substitutions/site/year). Phylogeography analyses show that the diversification of BYDV-PAV can be explained by local geographic adaptation as well as by host-driven adaptation. These results increase our understanding of the diversity, molecular evolutionary characteristics and epidemiological properties of an economically important plant RNA virus

    Identification of differentially expressed microRNAs in human male breast cancer

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    <p>Abstract</p> <p>Background</p> <p>The discovery of small non-coding RNAs and the subsequent analysis of microRNA expression patterns in human cancer specimens have provided completely new insights into cancer biology. Genetic and epigenetic data indicate oncogenic or tumor suppressor function of these pleiotropic regulators. Therefore, many studies analyzed the expression and function of microRNA in human breast cancer, the most frequent malignancy in females. However, nothing is known so far about microRNA expression in male breast cancer, accounting for approximately 1% of all breast cancer cases.</p> <p>Methods</p> <p>The expression of 319 microRNAs was analyzed in 9 primary human male breast tumors and in epithelial cells from 15 male gynecomastia specimens using fluorescence-labeled bead technology. For identification of differentially expressed microRNAs data were analyzed by cluster analysis and selected statistical methods.</p> <p>Expression levels were validated for the most up- or down-regulated microRNAs in this training cohort using real-time PCR methodology as well as in an independent test cohort comprising 12 cases of human male breast cancer.</p> <p>Results</p> <p>Unsupervised cluster analysis separated very well male breast cancer samples and control specimens according to their microRNA expression pattern indicating cancer-specific alterations of microRNA expression in human male breast cancer. miR-21, miR519d, miR-183, miR-197, and miR-493-5p were identified as most prominently up-regulated, miR-145 and miR-497 as most prominently down-regulated in male breast cancer.</p> <p>Conclusions</p> <p>Male breast cancer displays several differentially expressed microRNAs. Not all of them are shared with breast cancer biopsies from female patients indicating male breast cancer specific alterations of microRNA expression.</p

    Cell Membrane Is Impaired, Accompanied by Enhanced Type III Secretion System Expression in Yersinia pestis Deficient in RovA Regulator

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    BACKGROUND: In the enteropathogenic Yersinia species, RovA regulates the expression of invasin, which is important for enteropathogenic pathogenesis but is inactivated in Yersinia pestis. Investigation of the RovA regulon in Y. pestis at 26 °C has revealed that RovA is a global regulator that contributes to virulence in part by the direct regulation of psaEFABC. However, the regulatory roles of RovA in Y. pestis at 37 °C, which allows most virulence factors in mammalian hosts to be expressed, are still poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: The transcriptional profile of an in-frame rovA mutant of Y. pestis biovar Microtus strain 201 was analyzed under type III secretion system (T3SS) induction conditions using microarray techniques, and it was revealed that many cell-envelope and transport/binding proteins were differentially expressed in the ΔrovA mutant. Most noticeably, many of the T3SS genes, including operons encoding the translocon, needle and Yop (Yersinia outer protein) effectors, were significantly up-regulated. Analysis of Yop proteins confirmed that YopE and YopJ were also expressed in greater amounts in the mutant. However, electrophoresis mobility shift assay results demonstrated that the His-RovA protein could not bind to the promoter sequences of the T3SS genes, suggesting that an indirect regulatory mechanism is involved. Transmission electron microscopy analysis indicated that there are small loose electron dense particle-like structures that surround the outer membrane of the mutant cells. The bacterial membrane permeability to CFSE (carboxyfluorescein diacetate succinimidyl ester) was significantly decreased in the ΔrovA mutant compared to the wild-type strain. Taken together, these results revealed the improper construction and dysfunction of the membrane in the ΔrovA mutant. CONCLUSIONS/SIGNIFICANCE: We demonstrated that the RovA regulator plays critical roles in the construction and functioning of the bacterial membrane, which sheds considerable light on the regulatory functions of RovA in antibiotic resistance and environmental adaptation. The expression of T3SS was upregulated in the ΔrovA mutant through an indirect regulatory mechanism, which is possibly related to the altered membrane construction in the mutant
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