161 research outputs found

    Utility of a next generation framework for assessment of genomic damage: A case study using the industrial chemical benzene

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    We recently published a next generation framework for assessing the risk of genomic damage via exposure to chemical substances. The framework entails a systematic approach with the aim to quantify risk levels for substances that induce genomic damage contributing to human adverse health outcomes. Here, we evaluated the utility of the framework for assessing the risk for industrial chemicals, using the case of benzene. Benzene is a well‐studied substance that is generally considered a genotoxic carcinogen and is known to cause leukemia. The case study limits its focus on occupational and general population health as it relates to benzene exposure. Using the framework as guidance, available data on benzene considered relevant for assessment of genetic damage were collected. Based on these data, we were able to conduct quantitative analyses for relevant data sets to estimate acceptable exposure levels and to characterize the risk of genetic damage. Key observations include the need for robust exposure assessments, the importance of information on toxicokinetic properties, and the benefits of cheminformatics. The framework points to the need for further improvement on understanding of the mechanism(s) of action involved, which would also provide support for the use of targeted tests rather than a prescribed set of assays. Overall, this case study demonstrates the utility of the next generation framework to quantitatively model human risk on the basis of genetic damage, thereby enabling a new, innovative risk assessment concept. Environ. Mol. Mutagen. 61:94–113, 2020. © 2019 The Authors. Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society.JRC.F.3-Chemicals Safety and Alternative Method

    Impaired Functions of Peripheral Blood Monocyte Subpopulations in Aged Humans

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    Aging is associated with increased susceptibility to microbial infections, and monocytes play an important role in microbial defense. In this study, we have identified and compared four subpopulations of monocytes (CD14++(high)CD16−, CD14+(low)CD16−, CD14++(high)CD16+, and CD14+(low)CD16+) in the peripheral blood of young and aged subjects with regard to their numbers, cytokine production, TLR expression, and phosphorylation of ERK1/2 in response to pam3Cys a TLR-1/2 ligand. Proportions and numbers of CD14++(high)CD16+ and CD14+(low)CD16+ monocytes were significantly increased, whereas proportions of CD14+(low)CD16− monocytes were decreased in aged subjects as compared to young subjects. In aged subjects, IL-6 production by all four subsets of monocytes was significantly decreased, whereas TNF-α production was decreased in monocyte subsets, except the CD14+(low)CD16− subset. A significantly reduced expression of TLR1 was observed in CD14++(high)CD16+ and CD14+(low)CD16+ monocyte subsets in aged subjects. Furthermore, following pam3Cys stimulation, ERK1/2 phosphorylation was significantly lower in CD14+(low)CD16+, CD14++(high)CD16+, and CD14+(low)CD16− subsets of monocytes from aged subjects. This is the first study of four subpopulations of monocytes in aging, which demonstrates that their functions are differentially impaired with regard to the production of cytokines, expression of TLR, and signaling via the ERK–MAPK pathway. Finally, changes in the number of monocyte subsets, and impairment of TLR1 expression, TNF-α production, and EK1/2 phosphorylation was more consistent in CD16+ monocyte subsets regardless of expression of CD14high or CD14+low, therefore highlighting the significance of further subdivision of monocytes into four subpopulations

    A software pipeline for processing and identification of fungal ITS sequences

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    <p>Abstract</p> <p>Background</p> <p>Fungi from environmental samples are typically identified to species level through DNA sequencing of the nuclear ribosomal internal transcribed spacer (<it>ITS</it>) region for use in BLAST-based similarity searches in the International Nucleotide Sequence Databases. These searches are time-consuming and regularly require a significant amount of manual intervention and complementary analyses. We here present software – in the form of an identification pipeline for large sets of fungal <it>ITS </it>sequences – developed to automate the BLAST process and several additional analysis steps. The performance of the pipeline was evaluated on a dataset of 350 <it>ITS </it>sequences from fungi growing as epiphytes on building material.</p> <p>Results</p> <p>The pipeline was written in Perl and uses a local installation of NCBI-BLAST for the similarity searches of the query sequences. The variable subregion <it>ITS2 </it>of the <it>ITS </it>region is extracted from the sequences and used for additional searches of higher sensitivity. Multiple alignments of each query sequence and its closest matches are computed, and query sequences sharing at least 50% of their best matches are clustered to facilitate the evaluation of hypothetically conspecific groups. The pipeline proved to speed up the processing, as well as enhance the resolution, of the evaluation dataset considerably, and the fungi were found to belong chiefly to the <it>Ascomycota</it>, with <it>Penicillium </it>and <it>Aspergillus </it>as the two most common genera. The <it>ITS2 </it>was found to indicate a different taxonomic affiliation than did the complete <it>ITS </it>region for 10% of the query sequences, though this figure is likely to vary with the taxonomic scope of the query sequences.</p> <p>Conclusion</p> <p>The present software readily assigns large sets of fungal query sequences to their respective best matches in the international sequence databases and places them in a larger biological context. The output is highly structured to be easy to process, although it still needs to be inspected and possibly corrected for the impact of the incomplete and sometimes erroneously annotated fungal entries in these databases. The open source pipeline is available for UNIX-type platforms, and updated releases of the target database are made available biweekly. The pipeline is easily modified to operate on other molecular regions and organism groups.</p

    An iron-based beverage, HydroFerrate fluid (MRN-100), alleviates oxidative stress in murine lymphocytes in vitro

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    BackgroundSeveral studies have examined the correlation between iron oxidation and H2O2 degradation. The present study was carried out to examine the protective effects of MRN-100 against stress-induced apoptosis in murine splenic cells in vitro. MRN-100, or HydroFerrate fluid, is an iron-based beverage composed of bivalent and trivalent ferrates.MethodsSplenic lymphocytes from mice were cultured in the presence or absence of MRN-100 for 2 hrs and were subsequently exposed to hydrogen peroxide (H2O2) at a concentration of 25 μM for 14 hrs. Percent cell death was examined by flow cytometry and trypan blue exclusion. The effect of MRN-100 on Bcl-2 and Bax protein levels was determined by Western blot.ResultsResults show, as expected, that culture of splenic cells with H2O2 alone results in a significant increase in cell death (apoptosis) as compared to control (CM) cells. In contrast, pre-treatment of cells with MRN-100 followed by H2O2 treatment results in significantly reduced levels of apoptosis. In addition, MRN-100 partially prevents H2O2-induced down-regulation of the anti-apoptotic molecule Bcl-2 and upregulation of the pro-apoptotic molecule Bax.ConclusionOur findings suggest that MRN-100 may offer a protective effect against oxidative stress-induced apoptosis in lymphocytes

    Leptin Activates Human B Cells to Secrete TNF-α, IL-6, and IL-10 via JAK2/STAT3 and p38MAPK/ERK1/2 Signaling Pathway

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    Leptin, one of the adipokines, functions as a hormone and a cytokine. In this investigation, we show for the first time that leptin, in a concentration-dependent manner, activates human peripheral blood B cells to induce secretion of IL-6, IL-10, and TNF-α. Leptin increased B cells expressing CD25 and HLA-DR. Leptin induces phosphorylation of Janus activation kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3), p38 mitogen-activated protein kinase (p38MAPK), and extracellular signal-regulated kinase (ERK1/2). Furthermore, leptin-induced cytokine secretion by B cells was blocked by inhibitors of JAK2, STAT3, p38MAPK, and ERK1/2. These data demonstrate that leptin activates human B cells to secrete cytokines via activation of JAK2/STAT3 and p38MAPK/ERK1/2 signaling pathways, which may contribute to its inflammatory and immunoregulatory properties

    Cytotoxic Withanolide Constituents of Physalis longifolia

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    Fourteen new withanolides, 1–14, named withalongolides A–N, respectively, were isolated from the aerial parts of Physalis longifolia together with eight known compounds (15–22). The structures of compounds 1–14 were elucidated through spectroscopic techniques and chemical methods. In addition, the structures of withanolides 1, 2, 3, and 6 were confirmed by X-ray crystallographic analysis. Using a MTS viability assay, eight withanolides (1, 2, 3, 7, 8, 15, 16, and 19) and four acetylated derivatives (1a, 1b, 2a, and 2b) showed potent cytotoxicity against human head and neck squamous cell carcinoma (JMAR and MDA-1986), melanoma (B16F10 and SKMEL-28), and normal fetal fibroblast (MRC-5) cells with IC50 values in the range between 0.067 and 9.3 μM
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