393 research outputs found
Nerve Agent Hydrolysis Activity Designed into a Human Drug Metabolism Enzyme
Organophosphorus (OP) nerve agents are potent suicide inhibitors of the essential neurotransmitter-regulating enzyme acetylcholinesterase. Due to their acute toxicity, there is significant interest in developing effective countermeasures to OP poisoning. Here we impart nerve agent hydrolysis activity into the human drug metabolism enzyme carboxylesterase 1. Using crystal structures of the target enzyme in complex with nerve agent as a guide, a pair of histidine and glutamic acid residues were designed proximal to the enzyme's native catalytic triad. The resultant variant protein demonstrated significantly increased rates of reactivation following exposure to sarin, soman, and cyclosarin. Importantly, the addition of these residues did not alter the high affinity binding of nerve agents to this protein. Thus, using two amino acid substitutions, a novel enzyme was created that efficiently converted a group of hemisubstrates, compounds that can start but not complete a reaction cycle, into bona fide substrates. Such approaches may lead to novel countermeasures for nerve agent poisoning
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The evolution of imprinting: chromosomal mapping of orthologues of mammalian imprinted domains in monotreme and marsupial mammals.
BACKGROUND: The evolution of genomic imprinting, the parental-origin specific expression of genes, is the subject of much debate. There are several theories to account for how the mechanism evolved including the hypothesis that it was driven by the evolution of X-inactivation, or that it arose from an ancestrally imprinted chromosome. RESULTS: Here we demonstrate that mammalian orthologues of imprinted genes are dispersed amongst autosomes in both monotreme and marsupial karyotypes. CONCLUSION: These data, along with the similar distribution seen in birds, suggest that imprinted genes were not located on an ancestrally imprinted chromosome or associated with a sex chromosome. Our results suggest imprinting evolution was a stepwise, adaptive process, with each gene/cluster independently becoming imprinted as the need arose.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are
Carbon dioxide and ocean acidification observations in UK waters. Synthesis report with a focus on 2010–2015
Key messages: 1.1 The process of ocean acidification is now relatively well-documented at the global scale as a long-term trend in the open ocean. However, short-term and spatial variability can be high. 1.2 New datasets made available since Charting Progress 2 make it possible to greatly improve the characterisation of CO2 and ocean acidification in UK waters. 3.1 Recent UK cruise data contribute to large gaps in national and global datasets. 3.2 The new UK measurements confirm that pH is highly variable, therefore it is important to measure consistently to determine any long term trends. 3.3 Over the past 30 years, North Sea pH has decreased at 0.0035±0.0014 pH units per year. 3.4 Upper ocean pH values are highest in spring, lowest in autumn. These changes reflect the seasonal cycles in photosynthesis, respiration (decomposition) and water mixing. 3.5 Carbonate saturation states are minimal in the winter, and lower in 7 more northerly, colder waters. This temperature-dependence could have implications for future warming of the seas. 3.6 Over the annual cycle, North-west European seas are net sinks of CO2. However, during late summer to autumn months, some coastal waters may be significant sources. 3.7 In seasonally-stratified waters, sea-floor organisms naturally experience lower pH and saturation states; they may therefore be more vulnerable to threshold changes. 3.8 Large pH changes (0.5 - 1.0 units) can occur in the top 1 cm of sediment; however, such effects are not well-documented. 3.9 A coupled forecast model estimates the decrease in pH trend within the North Sea to be -0.0036±0.00034 pH units per year, under a high greenhouse gas emissions scenario (RCP 8.5). 3.10 Seasonal estimates from the forecast model demonstrate areas of the North Sea that are particularly vulnerable to aragonite undersaturation
A trans-homologue interaction between reciprocally imprinted miR-127 and Rtl1 regulates placenta development.
The paternally expressed imprinted retrotransposon-like 1 (Rtl1) is a retrotransposon-derived gene that has evolved a function in eutherian placentation. Seven miRNAs, including miR-127, are processed from a maternally expressed antisense Rtl1 transcript (Rtl1as) and regulate Rtl1 levels through RNAi-mediated post-transcriptional degradation. To determine the relative functional role of Rtl1as miRNAs in Rtl1 dosage, we generated a mouse specifically deleted for miR-127. The miR-127 knockout mice exhibit placentomegaly with specific defects within the labyrinthine zone involved in maternal-fetal nutrient transfer. Although fetal weight is unaltered, specific Rtl1 transcripts and protein levels are increased in both the fetus and placenta. Phenotypic analysis of single (ΔmiR-127/Rtl1 or miR-127/ΔRtl1) and double (ΔmiR-127/ΔRtl1) heterozygous miR-127- and Rtl1-deficient mice indicate that Rtl1 is the main target gene of miR-127 in placental development. Our results demonstrate that miR-127 is an essential regulator of Rtl1, mediated by a trans-homologue interaction between reciprocally imprinted genes on the maternally and paternally inherited chromosomes.This work was supported by the Biotechnology and Biological Sciences Research Council (BBSRC) and Medical Research Council (MRC) and EU FP7 Marie Curie Action 290123 (INGENIUM). This work was partly funded by a National Health and Medical Research Council (NHMRC) CJ Martin Biomedical Fellowship to A.N.S.P.This is the accepted manuscript. The final version is available at http://dev.biologists.org/content/early/2015/07/01/dev.121996.abstract
Community pharmacy interventions for health promotion: effects on professional practice and health outcomes (Protocol)
This is the protocol for a review and there is no abstract. The objectives are as follows: Primary objective To assess the effectiveness of health promotion interventions in community pharmacy practice settings on pharmacy workers and pharmacy clients (including diagnosed patients) when compared to i) No treatment controls ii) Usual treatment controls iii) Other active intervention Secondary objectives To assess whether there are differences in effectiveness of health promotion interventions in community pharmacy practice settings on i) Pharmacy worker ii) Client (patient) with regard to: i) Ethnicity of patients ii) Country income level (World Bank Group 2009) iii) Extent of adverse health behaviour (defined according to national guidelines where available) iv) Type of pharmacy worker delivering the intervention (e.g. pharmacist versus pharmacist technician) v) Theoretical constructs/components and behaviour change techniques employed in the intervention vi) Costs of health car
Targeted deletion of a 170-kb cluster of LINE-1 repeats and implications for regional control.
Approximately half the mammalian genome is composed of repetitive sequences, and accumulating evidence suggests that some may have an impact on genome function. Here, we characterized a large array class of repeats of long-interspersed elements (LINE-1). Although widely distributed in mammals, locations of such arrays are species specific. Using targeted deletion, we asked whether a 170-kb LINE-1 array located at a mouse imprinted domain might function as a modulator of local transcriptional control. The LINE-1 array is lamina associated in differentiated ES cells consistent with its AT-richness, and although imprinting occurs both proximally and distally to the array, active LINE-1 transcripts within the tract are biallelically expressed. Upon deletion of the array, no perturbation of imprinting was observed, and abnormal phenotypes were not detected in maternal or paternal heterozygous or homozygous mutant mice. The array does not shield nonimprinted genes in the vicinity from local imprinting control. Reduced neural expression of protein-coding genes observed upon paternal transmission of the deletion is likely due to the removal of a brain-specific enhancer embedded within the LINE array. Our findings suggest that presence of a 170-kb LINE-1 array reflects the tolerance of the site for repeat insertion rather than an important genomic function in normal development
Multisite Promiscuity in the Processing of Endogenous Substrates by Human Carboxylesterase 1
Human carboxylesterase 1 (hCE1) is a drug- and endobiotic-processing serine hydrolase that exhibits relatively broad substrate specificity. It has been implicated in a variety of endogenous cholesterol metabolism pathways including the following apparently disparate reactions: cholesterol ester hydrolysis (CEH), fatty acyl Coenzyme A hydrolysis (FACoAH), acyl-CoenzymeA:cholesterol acyltransfer (ACAT), and fatty acyl ethyl ester synthesis (FAEES). The structural basis for the ability of hCE1 to perform these catalytic actions involving large substrates and products has remained unclear. Here we present four crystal structures of the hCE1 glycoprotein in various complexes with endogenous substrates or substrate analogues: Coenzyme A, the fatty acid palmitate, and the bile acids cholate and taurocholate. While the active site of hCE1 was known to be promiscuous and capable of interacting with a variety of chemically-distinct ligands, these structures reveal that the enzyme contains two additional ligand binding sites and that each site also exhibits relatively non-specific ligand binding properties. Using this multisite promiscuity, hCE1 appears structurally capable of assembling several catalytic events depending, apparently, on the physiological state of the cellular environment. These results expand our understanding of enzyme promiscuity and indicate that, in the case of hCE1, multiple non-specific sites are employed to perform distinct catalytic actions
Clinical Practice Guidelines for the Management Candidiasis: 2009 Update by the Infectious Diseases Society of America
Guidelines for the management of patients with invasive candidiasis and mucosal candidiasis were prepared by an Expert Panel of the Infectious Diseases Society of America. These updated guidelines replace the previous guidelines published in the 15 January 2004 issue of Clinical Infectious Diseases and are intended for use by health care providers who care for patients who either have or are at risk of these infections. Since 2004, several new antifungal agents have become available, and several new studies have been published relating to the treatment of candidemia, other forms of invasive candidiasis, and mucosal disease, including oropharyngeal and esophageal candidiasis. There are also recent prospective data on the prevention of invasive candidiasis in high-risk neonates and adults and on the empiric treatment of suspected invasive candidiasis in adults. This new information is incorporated into this revised documen
MCP1 SNPs and Pulmonary Tuberculosis in Cohorts from West Africa, the USA and Argentina: Lack of Association or Epistasis with IL12B Polymorphisms
The monocyte chemotactic protein-1 (MCP-1) is a chemokine that plays an important role in the recruitment of monocytes to M. tuberculosis infection sites, and previous studies have reported that genetic variants in MCP1 are associated with differential susceptibility to pulmonary tuberculosis (PTB). We examined eight MCP1 single nucleotide polymorphisms (SNPs) in a multi-ethnic, case-control design that included: 321 cases and 346 controls from Guinea-Bissau, 258 cases and 271 controls from The Gambia, 295 cases and 179 controls from the U.S. (African-Americans), and an additional set of 237 cases and 144 controls of European ancestry from the U.S. and Argentina. Two locus interactions were also examined for polymorphisms in MCP1 and interleukin 12B (IL12B), another gene implicated in PTB risk. Examination of previously associated MCP1 SNPs rs1024611 (−2581A/G), rs2857656 (−362G/C) and rs4586 (+900C/T) did not show evidence for association. One interaction between rs2857656 and IL12B SNP rs2288831 was observed among Africans but the effect was in the opposite direction in Guineans (OR = 1.90, p = 0.001) and Gambians (OR = 0.64, p = 0.024). Our data indicate that the effect of genetic variation within MCP1 is not clear cut and additional studies will be needed to elucidate its role in TB susceptibility
Early Change in Albuminuria with Canagliflozin Predicts Kidney and Cardiovascular Outcomes:A Post Hoc Analysis from the CREDENCE Trial
Background The association between early changes in albuminuria and kidney and cardiovascular events is primarily based on trials of renin-angiotensin system blockade. It is unclear whether this association occurs with sodium-glucose cotransporter 2 inhibition. Methods TheCanagliflozin and Renal Events inDiabeteswith EstablishedNephropathy Clinical Evaluation (CREDENCE) trial enrolled 4401 patients with type 2 diabetes and CKD (urinary albumin-creatinine ratio [UACR].300 mg/g). This post hoc analysis assessed canagliflozin's effect on albuminuria and how early change in albuminuria (baseline to week 26) is associated with the primary kidney outcome (ESKD, doubling of serum creatinine, or kidney death), major adverse cardiovascular events, and hospitalization for heart failure or cardiovascular death. Results Complete data for early change in albuminuria and other covariates were available for 3836 (87.2%) participants in the CREDENCE trial. Compared with placebo, canagliflozin lowered UACR by 31% (95% confidence interval [95% CI], 27% to 36%) at week 26, and significantly increased the likelihood of achieving a 30% reduction in UACR ( odds ratio, 2.69; 95% CI, 2.35 to 3.07). Each 30% decrease in UACR over the first 26 weeks was independently associated with a lower hazard for the primary kidney outcome (hazard ratio [HR], 0.71; 95% CI, 0.67 to 0.76; P,0.001), major adverse cardiovascular events (HR, 0.92; 95% CI, 0.88 to 0.96; P,0.001), and hospitalization for heart failure or cardiovascular death (HR, 0.86; 95% CI, 0.81 to 0.90; P,0.001). Residual albuminuria levels at week 26 remained a strong independent risk factor for kidney and cardiovascular events, overall and in each treatment arm. Conclusions In people with type 2 diabetes and CKD, use of canagliflozin results in early, sustained reductions in albuminuria, which were independently associated with long-term kidney and cardiovascular outcomes
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