899 research outputs found

    Isolation of deoxynivalenol-transforming bacteria from the chicken intestines using the approach of PCR-DGGE guided microbial selection

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    <p>Abstract</p> <p>Background</p> <p>Contamination of grains with trichothecene mycotoxins, especially deoxynivalenol (DON), has been an ongoing problem for Canada and many other countries. Mycotoxin contamination creates food safety risks, reduces grain market values, threatens livestock industries, and limits agricultural produce exports. DON is a secondary metabolite produced by some <it>Fusarium </it>species of fungi. To date, there is a lack of effective and economical methods to significantly reduce the levels of trichothecene mycotoxins in food and feed, including the efforts to breed <it>Fusarium </it>pathogen-resistant crops and chemical/physical treatments to remove the mycotoxins. Biological approaches, such as the use of microorganisms to convert the toxins to non- or less toxic compounds, have become a preferred choice recently due to their high specificity, efficacy, and environmental soundness. However, such approaches are often limited by the availability of microbial agents with the ability to detoxify the mycotoxins. In the present study, an approach with PCR-DGGE guided microbial selection was developed and used to isolate DON -transforming bacteria from chicken intestines, which resulted in the successful isolation of several bacterial isolates that demonstrated the function to transform DON to its de-epoxy form, deepoxy-4-deoxynivalenol (DOM-1), a product much less toxic than DON.</p> <p>Results</p> <p>The use of conventional microbiological selection strategies guided by PCR-DGGE (denaturing gradient gel electrophoresis) bacterial profiles for isolating DON-transforming bacteria has significantly increased the efficiency of the bacterial selection. Ten isolates were identified and isolated from chicken intestines. They were all able to transform DON to DOM-1. Most isolates were potent in transforming DON and the activity was stable during subculturing. Sequence data of partial 16S rRNA genes indicate that the ten isolates belong to four different bacterial groups, Clostridiales, <it>Anaerofilum</it>, <it>Collinsella</it>, and <it>Bacillus</it>.</p> <p>Conclusions</p> <p>The approach with PCR-DGGE guided microbial selection was effective in isolating DON-transforming bacteria and the obtained bacterial isolates were able to transform DON.</p

    Febuxostat methanol solvate

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    In the title compound {systematic name: [2-(3-cyano-4-isobutyl­oxyphen­yl)-4-methyl-1,3-thia­zole-5-carb­oxy­lic acid (febuxostat) methanol monosolvate}, C16H16N2O3S·CH4O, the benzene and thia­zole rings in the febuxostat mol­ecule are twisted at 5.3 (1)°. In the crystal structure, inter­molecular O—H⋯O and O—H⋯N hydrogen bonds link the febuxostat and methanol mol­ecules into helical chains along the 21 screw axis

    A High-Performance Mid-infrared Optical Switch Enabled by Bulk Dirac Fermions in Cd3As2

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    Pulsed lasers operating in the 2-5 {\mu}m band are important for a wide range of applications in sensing, spectroscopy, imaging and communications. Despite recent advances with mid-infrared gain media, the lack of a capable pulse generation mechanism, i.e. a passive optical switch, remains a significant technological challenge. Here we show that mid-infrared optical response of Dirac states in crystalline Cd3As2, a three-dimensional topological Dirac semimetal (TDS), constitutes an ideal ultrafast optical switching mechanism for the 2-5 {\mu}m range. Significantly, fundamental aspects of the photocarrier processes, such as relaxation time scales, are found to be flexibly controlled through element doping, a feature crucial for the development of convenient mid-infrared ultrafast sources. Although various exotic physical phenomena have been uncovered in three-dimensional TDS systems, our findings show for the first time that this emerging class of quantum materials can be harnessed to fill a long known gap in the field of photonics.Comment: 17 pages, 3 figure

    Cuprous oxide nanoparticles selectively induce apoptosis of tumor cells

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    In the rapid development of nanoscience and nanotechnology, many researchers have discovered that metal oxide nanoparticles have very useful pharmacological effects. Cuprous oxide nanoparticles (CONPs) can selectively induce apoptosis and suppress the proliferation of tumor cells, showing great potential as a clinical cancer therapy. Treatment with CONPs caused a G1/G0 cell cycle arrest in tumor cells. Furthermore, CONPs enclosed in vesicles entered, or were taken up by mitochondria, which damaged their membranes, thereby inducing apoptosis. CONPs can also produce reactive oxygen species (ROS) and initiate lipid peroxidation of the liposomal membrane, thereby regulating many signaling pathways and influencing the vital movements of cells. Our results demonstrate that CONPs have selective cytotoxicity towards tumor cells, and indicate that CONPs might be a potential nanomedicine for cancer therapy

    Minimal effect of sleep on the risk of age-related macular degeneration: a Mendelian randomization study

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    AimsObservational studies have shown that sleep pattern is associated with age-related macular degeneration (AMD), but whether sleep pattern is a causal factor for AMD remains unclear. This study aims to use Mendelian randomization (MR) analysis to investigate the potential causal relationship between sleep traits and AMD.MethodsThis is a two-sample MR study. The single-nucleotide polymorphisms associated with AMD and early AMD were selected as the outcome from two different genome-wide association studies (GWAS): the early AMD GWAS with 14,034 cases and 91,214 controls, and AMD GWAS with 3,553 cases and 147,089 controls. The datasets of sleep duration, daytime dozing, and sleeplessness were used as exposure, which comprised nearly 0.46 million participants. Inverse-variance weighted method was used as the main result, and comprehensive sensitivity analyses were conducted to estimate the robustness of identified associations and the impact of potential horizontal pleiotropy.ResultsThrough MR analysis, we found that sleep duration was significantly associated with AMD (OR = 0.983, 95% CI = 0.970–0.996, P-value = 0.01). We also found suggestive evidence for the association of genetically predicted sleep duration with early AMD, which showed a consistent direction of effect with a marginal significance (OR = 0.724, 95% CI = 0.503–1.041, P-value = 0.08). Sensitivity analyses further supported the robustness of the causal relationship between sleep duration and AMD. However, we were unable to determine the relationship between daytime dozing or sleeplessness and AMD (including early AMD) (P-value &gt; 0.05).ConclusionSleep duration affects the causal risk for AMD; that is, longer sleep duration reduces the risk of AMD, while shorter sleep duration increases the risk of AMD. Although the influence is minimal, keeping adequate sleep duration is recommended, especially for patients with intermediate or advanced AMD

    A simulation study on the measurement of D0-D0bar mixing parameter y at BES-III

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    We established a method on measuring the \dzdzb mixing parameter yy for BESIII experiment at the BEPCII e+e−e^+e^- collider. In this method, the doubly tagged ψ(3770)→D0D0‾\psi(3770) \to D^0 \overline{D^0} events, with one DD decays to CP-eigenstates and the other DD decays semileptonically, are used to reconstruct the signals. Since this analysis requires good e/πe/\pi separation, a likelihood approach, which combines the dE/dxdE/dx, time of flight and the electromagnetic shower detectors information, is used for particle identification. We estimate the sensitivity of the measurement of yy to be 0.007 based on a 20fb−120fb^{-1} fully simulated MC sample.Comment: 6 pages, 7 figure

    From hyper- to hypoinsulinemia and diabetes: effect of KCNH6 on insulin secretion

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    Glucose-stimulated insulin secretion from islet β cells is mediated by K channels. However, the role of non-K K channels in insulin secretion is largely unknown. Here, we show that a non-K K channel, KCNH6, plays a key role in insulin secretion and glucose hemostasis in humans and mice. KCNH6 p.P235L heterozygous mutation co-separated with diabetes in a four-generation pedigree. Kcnh6 knockout (KO) or Kcnh6 p.P235L knockin (KI) mice had a phenotype characterized by changing from hypoglycemia with hyperinsulinemia to hyperglycemia with insulin deficiency. Islets from the young KO mice had increased intracellular calcium concentration and increased insulin secretion. However, islets from the adult KO mice not only had increased intracellular calcium levels but also had remarkable ER stress and apoptosis, associated with loss of β cell mass and decreased insulin secretion. Therefore, dysfunction of KCNH6 causes overstimulation of insulin secretion in the short term and β cell failure in the long term.Yang et al. show that KCNH6 plays a key role in insulin secretion and glucose hemostasis in humans and mice. Dysfunction of KCNH6 results in a hyperinsulinemia phenotype in the short term and hypoinsulinemia and diabetes in the long term

    An Updated Search of Steady TeV γ−\gamma-Ray Point Sources in Northern Hemisphere Using the Tibet Air Shower Array

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    Using the data taken from Tibet II High Density (HD) Array (1997 February-1999 September) and Tibet-III array (1999 November-2005 November), our previous northern sky survey for TeV γ−\gamma-ray point sources has now been updated by a factor of 2.8 improved statistics. From 0.0∘0.0^{\circ} to 60.0∘60.0^{\circ} in declination (Dec) range, no new TeV γ−\gamma-ray point sources with sufficiently high significance were identified while the well-known Crab Nebula and Mrk421 remain to be the brightest TeV γ−\gamma-ray sources within the field of view of the Tibet air shower array. Based on the currently available data and at the 90% confidence level (C.L.), the flux upper limits for different power law index assumption are re-derived, which are approximately improved by 1.7 times as compared with our previous reported limits.Comment: This paper has been accepted by hepn

    Two loop electroweak corrections to Bˉ→Xsγ\bar B\rightarrow X_s\gamma and Bs0→μ+μ−B_s^0\rightarrow \mu^+\mu^- in the B-LSSM

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    The rare decays Bˉ→Xsγ\bar B\rightarrow X_s\gamma and Bs0→μ+μ−B_s^0\rightarrow \mu^+\mu^- are important to research new physics beyond standard model. In this work, we investigate two loop electroweak corrections to Bˉ→Xsγ\bar B\rightarrow X_s\gamma and Bs0→μ+μ−B_s^0\rightarrow \mu^+\mu^- in the minimal supersymmetric extension of the SM with local B−LB-L gauge symmetry (B-LSSM), under a minimal flavor violating assumption for the soft breaking terms. In this framework, new particles and new definition of squarks can affect the theoretical predictions of these two processes, with respect to the MSSM. Considering the constraints from updated experimental data, the numerical results show that the B-LSSM can fit the experimental data for the branching ratios of Bˉ→Xsγ\bar B\rightarrow X_s\gamma and Bs0→μ+μ−B_s^0\rightarrow \mu^+\mu^-. The results of the rare decays also further constrain the parameter space of the B-LSSM.Comment: 33 pages, 9 figures, Published in EPJ

    Altered gut fungi in systemic lupus erythematosus – A pilot study

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    ObjectiveGut fungi, as symbiosis with the human gastrointestinal tract, may regulate physiology via multiple interactions with host cells. The plausible role of fungi in systemic lupus erythematosus (SLE) is far from clear and need to be explored.MethodsA total of 64 subjects were recruited, including SLE, rheumatoid arthritis (RA), undifferentiated connective tissue diseases (UCTDs) patients and healthy controls (HCs). Fecal samples of subjects were collected. Gut fungi and bacteria were detected by ITS sequencing and 16S rRNA gene sequencing, respectively. Alpha and beta diversities of microbiota were analyzed. Linear discriminant analysis effect size analysis was performed to identify abundance of microbiota in different groups. The correlation network between bacterial and fungal microbiota was analyzed based on Spearman correlation.ResultsGut fungal diversity and community composition exhibited significant shifts in SLE compared with UCTDs, RA and HCs. Compared with HCs, the alpha and beta diversities of fungal microbiota decreased in SLE patients. According to principal coordinates analysis results, the constitution of fungal microbiota from SLE, RA, UCTDs patients and HCs exhibited distinct differences with a clear separation between fungal microbiota. There was dysbiosis in the compositions of fungal and bacterial microbiota in the SLE patients, compared to HCs. Pezizales, Cantharellales and Pseudaleuria were enriched in SLE compared with HCs, RA and UCTDs. There was a complex relationship network between bacterial and fungal microbiota, especially Candida which was related to a variety of bacteria.ConclusionThis study presents a pilot analysis of fungal microbiota with diversity and composition in SLE, and identifies several gut fungi with different abundance patterns taxa among SLE, RA, UCTDs and HCs. Furthermore, the gut bacterial-fungal association network in SLE patients was altered compared with HCs
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