The effects of legacy sulphur deposition on methylmercury production in northern peatlands; geochemical and biological considerations

Mercury is a ubiquitous element with a complex geochemical cycle. Aquatic ecosystems such as wetland soils convert inorganic mercury to organic, neurotoxic methylmercury though the activity of sulphate-reducing bacteria (SRB). Sulphate stimulates the activity of SRB, and the production of methylmercury in these environments. My aim was to investigate the effect that legacy sulphate has on Hg methylation in northern peatlands through a laboratory sulphate addition experiment with differentially sulphate-exposed peats and a field study of peatlands subjected to different levels of sulphate. Results from the laboratory study indicate that peatlands in regions of higher atmospheric sulphate deposition show enhanced Hg methylation responses compared to pristine peatlands, while field results indicate that sulphate deposition increases Hg methylation dependence on other nutrients as opposed to sulphate supply. Management for peatlands impacted by industrial sulphate sources will have to consider legacy sulphate deposition within peatland geochemical context to mitigate potential Hg methylation

The First Data Release of the Sloan Digital Sky Survey

The Sloan Digital Sky Survey has validated and made publicly available its First Data Release. This consists of 2099 square degrees of five-band (u, g, r, i, z) imaging data, 186,240 spectra of galaxies, quasars, stars and calibrating blank sky patches selected over 1360 square degrees of this area, and tables of measured parameters from these data. The imaging data go to a depth of r ~ 22.6 and are photometrically and astrometrically calibrated to 2% rms and 100 milli-arcsec rms per coordinate, respectively. The spectra cover the range 3800--9200 A, with a resolution of 1800--2100. Further characteristics of the data are described, as are the data products themselves.Comment: Submitted to The Astronomical Journal. 16 pages. For associated documentation, see http://www.sdss.org/dr

Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial

SummaryBackground Azithromycin has been proposed as a treatment for COVID-19 on the basis of its immunomodulatoryactions. We aimed to evaluate the safety and efficacy of azithromycin in patients admitted to hospital with COVID-19.Methods In this randomised, controlled, open-label, adaptive platform trial (Randomised Evaluation of COVID-19Therapy [RECOVERY]), several possible treatments were compared with usual care in patients admitted to hospitalwith COVID-19 in the UK. The trial is underway at 176 hospitals in the UK. Eligible and consenting patients wererandomly allocated to either usual standard of care alone or usual standard of care plus azithromycin 500 mg once perday by mouth or intravenously for 10 days or until discharge (or allocation to one of the other RECOVERY treatmentgroups). Patients were assigned via web-based simple (unstratified) randomisation with allocation concealment andwere twice as likely to be randomly assigned to usual care than to any of the active treatment groups. Participants andlocal study staff were not masked to the allocated treatment, but all others involved in the trial were masked to theoutcome data during the trial. The primary outcome was 28-day all-cause mortality, assessed in the intention-to-treatpopulation. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936.Findings Between April 7 and Nov 27, 2020, of 16 442 patients enrolled in the RECOVERY trial, 9433 (57%) wereeligible and 7763 were included in the assessment of azithromycin. The mean age of these study participants was65·3 years (SD 15·7) and approximately a third were women (2944 [38%] of 7763). 2582 patients were randomlyallocated to receive azithromycin and 5181 patients were randomly allocated to usual care alone. Overall,561 (22%) patients allocated to azithromycin and 1162 (22%) patients allocated to usual care died within 28 days(rate ratio 0·97, 95% CI 0·87–1·07; p=0·50). No significant difference was seen in duration of hospital stay (median10 days [IQR 5 to >28] vs 11 days [5 to >28]) or the proportion of patients discharged from hospital alive within 28 days(rate ratio 1·04, 95% CI 0·98–1·10; p=0·19). Among those not on invasive mechanical ventilation at baseline, nosignificant difference was seen in the proportion meeting the composite endpoint of invasive mechanical ventilationor death (risk ratio 0·95, 95% CI 0·87–1·03; p=0·24).Interpretation In patients admitted to hospital with COVID-19, azithromycin did not improve survival or otherprespecified clinical outcomes. Azithromycin use in patients admitted to hospital with COVID-19 should be restrictedto patients in whom there is a clear antimicrobial indication

A cleavable N-terminal signal peptide promotes widespread olfactory receptor surface expression in HEK293T cells.

Olfactory receptors (ORs) are G protein-coupled receptors that detect odorants in the olfactory epithelium, and comprise the largest gene family in the genome. Identification of OR ligands typically requires OR surface expression in heterologous cells; however, ORs rarely traffic to the cell surface when exogenously expressed. Therefore, most ORs are orphan receptors with no known ligands. To date, studies have utilized non-cleavable rhodopsin (Rho) tags and/or chaperones (i.e. Receptor Transporting Protein, RTP1S, Ric8b and G(αolf)) to improve surface expression. However, even with these tools, many ORs still fail to reach the cell surface. We used a test set of fifteen ORs to examine the effect of a cleavable leucine-rich signal peptide sequence (Lucy tag) on OR surface expression in HEK293T cells. We report here that the addition of the Lucy tag to the N-terminus increases the number of ORs reaching the cell surface to 7 of the 15 ORs (as compared to 3/15 without Rho or Lucy tags). Moreover, when ORs tagged with both Lucy and Rho were co-expressed with previously reported chaperones (RTP1S, Ric8b and G(αolf)), we observed surface expression for all 15 receptors examined. In fact, two-thirds of Lucy-tagged ORs are able to reach the cell surface synergistically with chaperones even when the Rho tag is removed (10/15 ORs), allowing for the potential assessment of OR function with only an 8-amino acid Flag tag on the mature protein. As expected for a signal peptide, the Lucy tag was cleaved from the mature protein and did not alter OR-ligand binding and signaling. Our studies demonstrate that widespread surface expression of ORs can be achieved in HEK293T cells, providing promise for future large-scale deorphanization studies

Chief Global Technical Advisor Halliburton Company Members

and Oil Resources, also approved the making available of certain materials used in the study process, including detailed, specific subject matter papers prepared or used by the study’s Task Groups and/or Subgroups. These Topic and White Papers were working documents that were part of the analyses that led to development of the summary results presented in the report’s Executive Summary and Chapters. These Topic and White Papers represent the views and conclusions of the authors. The National Petroleum Council has not endorsed or approved the statements and conclusions contained in these documents, but approved the publication of these materials as part of the study process. The NPC believes that these papers will be of interest to the readers of the report and will help them better understand the results. These materials are being made available in the interest of transparency. The attached paper is one of 57 such working documents used in the study analyses. Also included is a roster of the Subgroup that developed or submitted this paper. Appendix C of the final NPC report provides a complete list of the 57 Topic and Whit

A Renal Olfactory Receptor Aids in Kidney Glucose Handling

International audienceOlfactory receptors (ORs) are G protein-coupled receptors which serve important sensory functions beyond their role as odorant detectors in the olfactory epithelium. Here we describe a novel role for one of these ORs, Olfr1393, as a regulator of renal glucose handling. Olfr1393 is specifically expressed in the kidney proximal tubule, which is the site of renal glucose reabsorption. Olfr1393 knockout mice exhibit urinary glucose wasting and improved glucose tolerance, despite euglycemia and normal insulin levels. Consistent with this phenotype, Olfr1393 knockout mice have a significant decrease in luminal expression of Sglt1, a key renal glucose transporter, uncovering a novel regulatory pathway involving Olfr1393 and Sglt1. In addition, by utilizing a large scale screen of over 1400 chemicals we reveal the ligand profile of Olfr1393 for the first time, offering new insight into potential pathways of physiological regulation for this novel signaling pathway. Olfactory receptors (ORs) are seven transmembrane domain G protein-coupled receptors (GPCRs) that serve as the chemical sensors of smell in the olfactory epithelium (OE). While these receptors were originally thought to be restricted to the nose 1 , it is now appreciated that ORs and other sensory receptors are found in a variety of other tissues where they play important physiological functions 2–9. We previously reported that at least 10 different ORs as well as their downstream signaling components (adenylate cyclase 3 and the olfactory G protein) are expressed in the kidney, and that one of these renal ORs contributes to blood pressure regulation 6,10. However, the functions of the remaining renal ORs have remained a mystery. In this study, we report for the first time the localization, ligand profile and physiological relevance of renal Olfactory Receptor 1393 (Olfr1393). We find that Olfr1393 localizes to all three segments of the renal proximal tubule, which is the site of renal glucose reabsorption. Typically, an individual's entire blood volume is filtered ~50 times/day, and because glucose is neither protein-bound nor complexed with macromolecules, it is freely filtered by the glomerulus 11,12. Under normal conditions, the proximal tubule reabsorbs the entirety of the ~180 grams of glucose filtered per day from the ultra-filtrate, such that no glucose is detected in the final urine. Glucose reabsorption in the proximal tubule is mediated by two apical sodium-glucose co-transporters: Sglt2 (SCL5A2) and Sglt1 (SLC5A1) 11–14. The low affinity , high-flux transporter, Sglt2, is localized to the apical membrane of the early proximal tubule (S1 and S2) and handles > 90% of all glucose reabsorption. The remaining glucose is cleared from the lumen by the high affinity, low-flux transporter, Sglt1, in the straight proximal tubule (S3). While these transporters have been extensively characterized and explored as potential drug targets for type II diabetes 11,15,16 , the understanding of their regulation within the proximal tubule is limited 17. Here, we report that Olfr1393 knockout (KO) mice present with euglycemic glycosuria and improved glucose tolerance. Consistent with this, we observe an altered distribution of Sglt1 in the proximal tubule of KO animals, implicating Olfr1393 as a novel contributor to renal glucose handling. Additionally, when we began these studies, Olfr1393 was an 'orphan' receptor with no known ligands; therefore, we undertook a ligand screen and identified 8 ligands for Olfr1393. In sum, these studies have uncovered a novel role for a renal OR in kidney glucose handling , and have identified a novel mechanism for potential physiologic regulation of Sglt1

The Lucy tag does not alter OR signaling.

<p>(A) A luciferase reporter assay was performed for both Rho-Olfr691(R-691) and Lucy-Rho-Olfr691 (L-R-691) with and without RTP1S. Cells expressing the Olfr691 constructs were grown in a 96-well plate and exposed to the known Olfr691 ligand, isovaleric acid (0-5 mM). Error bars represent the SEM. By ANOVA and Student-Newman-Keuls, no concentrations of isovaleric acid activated R-691 (n/s = no significance). For R-691 + RTP1S, L-691, and L-691 + RTP1S, P ≤ 0.05 for 0 mM vs. all doses of isovaleric acid (marked by an *). In addition, for R-691 + RTP1S, P ≤ 0.05 for 5 vs 0.5, 0.25 and 0.1, 1 vs 0.25 and 0.1, 0.5 vs 0.1. For L-691, P ≤ 0.05 for 5 vs 0.1, 0.25 and 0.5. For L-691 + RTP1S, P ≤ 0.05 for 5 vs 0.5, 0.25 and 0.1, 1 vs 0.5, 0.25 and 0.1, 0.5 vs 0.1. (B) A luciferase reporter assay was performed for mOREG (EG), Rho-mOREG (R-EG), Lucy-mOREG (L-EG) and Lucy-Rho-mOREG (L-R-EG), all in the absence of RTP1S. Cells expressing the mOREG constructs were grown in a 96-well plate and exposed to the known mOREG ligand, eugenol (100-300 µM). Error bars represent the SEM. By ANOVA and Student-Newman-Keuls, all concentrations of eugenol significantly activated (P ≤ 0.05) eg, R-EG, L-EG and L-R-EG as compared to 0 µM (marked by an *). In addition, 100 and 300 µM eugenol were significant from each other (P ≤ 0.05) for both L-EG and L-R-EG. In both A and B, the Firefly: Renilla ratio was measured and compared to the non-treated control. An increase in the ratio indicates OR activation. Both Lucy-Rho-691 and Lucy-tagged mOREG constructs were activated with their ligands indicating that the Lucy tag does not alter OR signaling.</p