163 research outputs found

    HOW A SILENT MUTATION SUPPRESSES THE ACTIVITY AND IRON INCORPORATION IN SUPEROXIDE DISMUTASE

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    A mutation (CTG to TTG) of FeSOD gene was found in Escherichia coli. Since they both encode leucine, it is a silent mutation. Site-­‐directed mutagenesis was applied to correct the mutation, and the mutant FeSOD (before gene correction) and wild type FeSOD (after gene correction) were purified. The FeSODs from the two genes were Characterized using different assays and spectroscopic methods including EPR and CD. The requirement for the rare codon TTG may result in slowed translation and heavy demand on a scarce tRNA. Cultures expressing wild type FeSOD are better able to grow for long times after addition of IPTG and more mature to incorporate Fe atoms to the active sites than are cultures expressing the mutant gene. Moreover, the wild type FeSOD has more activity than the mutant. To our knowledge, this is the first time that a silent mutation has been demonstrated to affect metal incorporation into a metalloenzyme

    Outcome of Patients With Small Vessel Vasculitis After Renal Transplantation: National Database Analysis

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    Background. Small vessel vasculitis commonly affects the kidney and can progress to end-stage renal disease. The goal of this study is to compare outcomes of patients who received a renal transplant as a result of small vessel vasculitis (group A) with those who received kidney transplants because of other causes (group B). Methods. This is a retrospective analysis of United Network for Organ Sharing registry data for adult primary kidney transplants from January 2000 to December 2014. Group A patients (N = 2196) were compared with a group B (N = 6588); groups were case matched for age, race, sex, donor type, and year of transplant in a 1:3 ratio. Results. Renal and patient survivals were better in the group A (P \u3c 0.001). New-onset diabetes after transplant developed in 8.3% of the group A and 11.3% of group B (P \u3c 0.001). Seventeen (0.8%) patients in group A developed recurrent disease. Of these, 7 patients had graft failure, 3 of which were due to disease recurrence. Group A patients had significantly higher risk of developing posttransplant solid organ malignancies (11.3% vs 9.3%, P = 0.006) and lymphoproliferative disorder (1.3% vs 0.8%, P = 0.026). Independent predictors of graft failure and patient mortality were recipients\u27 morbid obesity, diabetes, age, and dialysis duration (hazard ratio of 1.7, 1.4, 1.1/10 years, and 1.1/year for graft failure, and 1.7, 1.7, 1.6/10 years and 1.1/year for patient mortality, respectively). Conclusions. Renal transplantation in patients with has favorable long-term graft and patient outcomes with a low disease recurrence rate. However, they may have a higher risk of developing posttransplant malignancies

    The beneficial effects of curcumin supplementation on blood lipid levels among patients with metabolic related diseases in Asia area: a systematic review and meta-analysis of randomized controlled trials

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    ObjectivePublished studies suggest that the effects of curcumin on blood lipids in adults are controversial, and it is unclear whether there is a dose response to lipid changes following curcumin supplementation. Therefore, we conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to evaluate the effects of curcumin on triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL), and high-density lipoprotein cholesterol (HDL) in the Asian populations with metabolic diseases.MethodsWe systematically searched four electronic databases, including Web of Science, PubMed, Google Scholar, and Cochrane Library, for randomized controlled trials (RCTs) of the effects of curcumin on TG, TC, LDL, and HDL in the Asian populations with metabolic diseases. Mean difference (MD) indicates effect size with combined 95% confidence interval (95% CI). Heterogeneity among studies was assessed by I2. Subgroup analyses were performed to explore potential sources of heterogeneity.ResultsEvidence from 23 RCTs for TG, 21 RCTs for TC and LDL, and 22 RCTs for HDL showed that curcumin supplementation significantly reduced TG (MD: −18.07 mg/dL, 95% CI: −30.30, −5.85, P < 0. 01), TC (MD: −13.29 mg/dL, 95% CI: −20.43, −6.16, P < 0.01), and LDL (MD: −10.44 mg/dL, 95% CI: −16.87, −4.00, P < 0.01), but no effect on HDL (MD: 1.66 mg/dL, 95% CI: −0.13, 3.44, P = 0.07). In the non-linear dose-response analysis, we observed a significant effect of curcumin supplementation dose on TG levels (P-non-linearity = 0.022).ConclusionIn conclusion, curcumin may be beneficial in reducing TG, TC, and LDL levels in the Asian populations with metabolic diseases. The dose of curcumin intervention may be an underlying factor influencing TG levels

    Expression of SET Protein in the Ovaries of Patients with Polycystic Ovary Syndrome

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    Background. We previously found that expression of SET gene was up-regulated in polycystic ovaries by using microarray. It suggested that SET may be an attractive candidate regulator involved in the pathophysiology of polycystic ovary syndrome (PCOS). In this study, expression and cellular localization of SET protein were investigated in human polycystic and normal ovaries. Method. Ovarian tissues, six normal ovaries and six polycystic ovaries, were collected during transsexual operation and surgical treatment with the signed consent form. The cellular localization of SET protein was observed by immunohistochemistry. The expression levels of SET protein were analyzed by Western Blot. Result. SET protein was expressed predominantly in the theca cells and oocytes of human ovarian follicles in both PCOS ovarian tissues and normal ovarian tissues. The level of SET protein expression in polycystic ovaries was triple higher than that in normal ovaries (P<0.05). Conclusion. SET was overexpressed in polycystic ovaries more than that in normal ovaries. Combined with its localization in theca cells, SET may participate in regulating ovarian androgen biosynthesis and the pathophysiology of hyperandrogenism in PCOS

    Neonatal Overfeeding Induced by Small Litter Rearing Causes Altered Glucocorticoid Metabolism in Rats

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    Elevated glucocorticoid (GC) activity may be involved in the development of the metabolic syndrome. Tissue GC exposure is determined by the tissue-specific GC-activating enzyme 11ÎČ-hydroxysteriod dehydrogenase type 1 (11ÎČ-HSD1) and the GC-inactivating enzyme 5α-reductase type 1 (5αR1), as well as 5ÎČ-reductase (5ÎČR). Our aim was to study the effects of neonatal overfeeding induced by small litter rearing on the expression of GC-regulating enzymes in adipose tissue and/or liver and on obesity-related metabolic disturbances during development. Male Sprague-Dawley rat pup litters were adjusted to litter sizes of three (small litters, SL) or ten (normal litters, NL) on postnatal day 3 and then given standard chow from postnatal week 3 onward (W3). Small litter rearing induced obesity, hyperinsulinemia, and higher circulating corticosterone in adults. 11ÎČ-HSD1 expression and enzyme activity in retroperitoneal, but not in epididymal, adipose tissue increased with postnatal time and peaked at W5/W6 in both groups before declining. From W8, 11ÎČ-HSD1 expression and enzyme activity levels in retroperitoneal fat persisted at significantly higher levels in SL compared to NL rats. Hepatic 11ÎČ-HSD1 enzyme activity in SL rats was elevated from W3 to W16 compared to NL rats. Hepatic 5αR1 and 5ÎČR expression was higher in SL compared to NL rats after weaning until W6, whereupon expression decreased in the SL rats and remained similar to that in NL rats. In conclusion, small litter rearing in rats induced peripheral tissue-specific alterations in 11ÎČ-HSD1 expression and activity and 5αR1 and 5ÎČR expression during puberty, which could contribute to elevated tissue-specific GC exposure and aggravate the development of metabolic dysregulation in adults

    Neutrino Physics with JUNO

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    The Jiangmen Underground Neutrino Observatory (JUNO), a 20 kton multi-purposeunderground liquid scintillator detector, was proposed with the determinationof the neutrino mass hierarchy as a primary physics goal. It is also capable ofobserving neutrinos from terrestrial and extra-terrestrial sources, includingsupernova burst neutrinos, diffuse supernova neutrino background, geoneutrinos,atmospheric neutrinos, solar neutrinos, as well as exotic searches such asnucleon decays, dark matter, sterile neutrinos, etc. We present the physicsmotivations and the anticipated performance of the JUNO detector for variousproposed measurements. By detecting reactor antineutrinos from two power plantsat 53-km distance, JUNO will determine the neutrino mass hierarchy at a 3-4sigma significance with six years of running. The measurement of antineutrinospectrum will also lead to the precise determination of three out of the sixoscillation parameters to an accuracy of better than 1\%. Neutrino burst from atypical core-collapse supernova at 10 kpc would lead to ~5000inverse-beta-decay events and ~2000 all-flavor neutrino-proton elasticscattering events in JUNO. Detection of DSNB would provide valuable informationon the cosmic star-formation rate and the average core-collapsed neutrinoenergy spectrum. Geo-neutrinos can be detected in JUNO with a rate of ~400events per year, significantly improving the statistics of existing geoneutrinosamples. The JUNO detector is sensitive to several exotic searches, e.g. protondecay via the p→K++Μˉp\to K^++\bar\nu decay channel. The JUNO detector will providea unique facility to address many outstanding crucial questions in particle andastrophysics. It holds the great potential for further advancing our quest tounderstanding the fundamental properties of neutrinos, one of the buildingblocks of our Universe

    Potential of Core-Collapse Supernova Neutrino Detection at JUNO

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    JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve

    Detection of the Diffuse Supernova Neutrino Background with JUNO

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    As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO

    Real-time Monitoring for the Next Core-Collapse Supernova in JUNO

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    Core-collapse supernova (CCSN) is one of the most energetic astrophysical events in the Universe. The early and prompt detection of neutrinos before (pre-SN) and during the SN burst is a unique opportunity to realize the multi-messenger observation of the CCSN events. In this work, we describe the monitoring concept and present the sensitivity of the system to the pre-SN and SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is a 20 kton liquid scintillator detector under construction in South China. The real-time monitoring system is designed with both the prompt monitors on the electronic board and online monitors at the data acquisition stage, in order to ensure both the alert speed and alert coverage of progenitor stars. By assuming a false alert rate of 1 per year, this monitoring system can be sensitive to the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos up to about 370 (360) kpc for a progenitor mass of 30M⊙M_{\odot} for the case of normal (inverted) mass ordering. The pointing ability of the CCSN is evaluated by using the accumulated event anisotropy of the inverse beta decay interactions from pre-SN or SN neutrinos, which, along with the early alert, can play important roles for the followup multi-messenger observations of the next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure

    Finishing the euchromatic sequence of the human genome

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    The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∌99% of the euchromatic genome and is accurate to an error rate of ∌1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead
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