BST1 regulates nicotinamide riboside metabolism via its glycohydrolase and base-exchange activities

Nicotinamide riboside (NR) is one of the orally bioavailable NAD+ precursors and has been demonstrated to exhibit beneficial effects against aging and aging-associated diseases. However, the metabolic pathway of NR in vivo is not yet fully understood. Here, we demonstrate that orally administered NR increases NAD+ level via two different pathways. In the early phase, NR was directly absorbed and contributed to NAD+ generation through the NR salvage pathway, while in the late phase, NR was hydrolyzed to nicotinamide (NAM) by bone marrow stromal cell antigen 1 (BST1), and was further metabolized by the gut microbiota to nicotinic acid, contributing to generate NAD+ through the Preiss–Handler pathway. Furthermore, we report BST1 has a base-exchange activity against both NR and nicotinic acid riboside (NAR) to generate NAR and NR, respectively, connecting amidated and deamidated pathways. Thus, we conclude that BST1 plays a dual role as glycohydrolase and base-exchange enzyme during oral NR supplementation.

Lipidomic profiling reveals biosynthetic relationships between phospholipids and diacylglycerol ethers in the deep-sea soft coral Paragorgia arborea

The cold-water gorgonian coral Paragorgia arborea is considered as a foundation species of deep-sea ecosystems in the northern Atlantic and Pacific oceans. To advance lipidomic studies of deep-sea corals, molecular species compositions of diacylglycerol ethers (DAGE), which are specific storage lipids of corals, and structural glycerophospholipids (GPL) including ethanolamine, choline, inositol and serine GPL (PE, PC, PI, and PS, respectively) were analyzed in P. arborea by HPLC and tandem mass spectrometry. In DAGE molecules, alkyl groups (16:0, 14:0, and 18:1), polyunsaturated fatty acids (PUFA), and monounsaturated FA are mainly substituted the glycerol moiety at position sn-1, sn-2, and sn-3, respectively. The ether form (1-O-alkyl-2-acyl) predominates in PE and PC, while PI is comprised of the 1,2-diacyl form. Both ether and diacyl forms were observed in PS. At position sn-2, C20 PUFA are mainly attached to PC, but C24 PUFA, soft coral chemotaxonomic markers, concentrate in PS, PI, and PE. A comparison of non-polar parts of molecules has shown that DAGE, ether PE, and ether PC can originate from one set of 1-O-alkyl-2-acyl-sn-glycerols. Ether PE may be converted to ether PS by the base-exchange reaction. A diacylglycerol unit generated from phosphatidic acid can be a precursor for diacyl PS, PC, and PI. Thus, a lipidomic approach has confirmed the difference in biosynthetic origins between ether and diacyl lipids of deep-sea gorgonians.

Integration of Scandinavian genetic data with UK biobank data implicates the RBM20 gene with atrial fibrillation pathogenesis

Purpose Atrial fibrillation (AF) is the most common sustained arrhythmia. It carries a large healthcare burden and is associated with serious complications. The arrhythmia has a substantial genetic component and is associated with several structural genes, including the gene TTN. A recent large genome-wide association study on AF found an association to RBM20. The RBM20 gene is a splicing factor targeting TTN, RYR2 and CAMK2D among other cardiac genes. Using Next-Generation Sequencing and data derived from the UK Biobank, we aimed to reveal the role of RBM20 in AF. Methods and results We examined the burden of rare (Minor allele frequency (MAF)<0.01%) RBM20 loss-of-function (LOF) variants in whole-exome sequencing data from the UK Biobank (n=175,280). AF was defined by ICD9/10, while individuals without AF were used as controls. Association tests aggregating rare variants in RBM20 using the Efficient Variant-Set Mixed Model Association Test (SMMAT) were performed to assess the effect of LOF RBM20 variants, adjusted for age, sex and principal components. We identified 33 LOF variants in RBM20, which were significantly enriched in AF (P=0.0087). To examine the effect of rare missense RBM20 variants in the splicing of TTN, we screened an in-house cohort of 531 Scandinavian early-onset AF patients using targeted sequencing. We filtered for rare (MAF<0.1%) and deleterious (defined as combined annotation dependent depletion score >20) variants and identified nine missense variants and three novel LOF variants in RBM20. To evaluate the effect of these RBM20 variants, we constructed a series of human RBM20 single nucleotide base exchange mutants. The splicing activity of the variants was measured with RT-qPCR on HEK293 cells transfected with a TTN241–3 splicing reporter. Four of these variants resulted in a significantly altered splicing activity in TTN, with the largest effect observed for LOF variants. In order to examine the biological effect of RBM20 variants on structural changes in atrial tissue, we used a Norwegian Brown rat animal model with loss of RBM20. In this model, Transmission Electron Microscopy revealed altered sarcomere and mitochondrial structure in its atrial cardiomyocytes. Furthermore, nanopore RNA sequencing of atrial tissue from the aforementioned animal model indicated altered expression in several key cardiac genes, including TTN and PITX2. Conclusion Rare RBM20 LOF variants are significantly enriched in AF cases, seen in a large population of 175,000 individuals. We demonstrated that the effect of LOF RBM20 on alternative TTN splicing can be detected on an individual level in patients with AF. Studies using an animal model indicates that LOF in RBM20 may affect atrial function through altered expression of several genes in the atria, and may cause structural changes in the atrial cardiomyocytes. This suggests that RBM20 may be involved in AF pathogenesis mediated through an atrial cardiomyopathy. FUNDunding Acknowledgement Type of funding sources: Foundation. Main funding source(s): Novo Nordisk Foundation Pre-Graduate Scholarships (NNF18OC0053094)The Hallas Møller Emerging Investigator grant (Novo Nordisk Foundation (NNF17OC0031204))

Quantum Algorithm of Imperfect KB Self-organization. Pt II: Robotic Control with Remote Knowledge Base Exchange

The technology of knowledge base remote design of the smart fuzzy controllers with the application of the "Soft / quantum computing optimizer" toolkit software developed. The possibility of the transmission and communication the knowledge base using remote connection to the control object considered. Transmission and communication of the fuzzy controller’s knowledge bases implemented through the remote connection with the control object in the online mode apply the Bluetooth or WiFi technologies. Remote transmission of knowledge bases allows designing many different built-in intelligent controllers to implement a variety of control strategies under conditions of uncertainty and risk. As examples, two different models of robots described (mobile manipulator and (“cart-pole” system) inverted pendulum). A comparison of the control quality between fuzzy controllers and quantum fuzzy controller in various control modes is presented. The ability to connect and work with a physical model of control object without using than mathematical model demonstrated. The implemented technology of knowledge base design sharing in a swarm of intelligent robots with quantum controllers. It allows to achieve the goal of control and to gain additional knowledge by creating a new quantum hidden information source based on the synergetic effect of combining knowledge. Development and implementation of intelligent robust controller’s prototype for the intelligent quantum control system of mega-science project NICA (at the first stage for the cooling system of superconducted magnets) is discussed. The results of the experiments demonstrate the possibility of the ensured achievement of the control goal of a group of robots using soft / quantum computing technologies in the design of knowledge bases of smart fuzzy controllers in quantum intelligent control systems. The developed software toolkit allows to design and setup complex ill-defined and weakly formalized technical systems on line.

Assessment of Major Sources Controlling Groundwater Chemistry in Kombolcha Plain, Eastern Amhara Region, Ethiopia

The study area, Kombolcha town, forms an important industrial town situated in the Eastern Amhara region, Ethiopia. The geology of the area is mainly composed of basalts, rhyolitic ignimbrites, and Quaternary sediments. Hydrogeochemistry and the source of ions in the groundwater of the study area are poorly understood. Therefore, the current study aims to assess the factors and the different hydrochemical processes significantly controlling groundwater quality, source, and chemistry. For this purpose, a total of eighteen groundwater samples were collected using 250 ml sampling bottles at selected points in the dry season (May 2017) and wet season (November 2017). Gibbs diagram, correlation analysis, scatter plots of ionic molar ratio relations, saturation index values (estimated using PHREEQC Interactive 2.8) were used to decipher the hydrogeochemical process. Gibbs diagram shows that the rock-water interaction process is the predominant, Na+/Cl- and Ca2+/Mg2+ molar ratio value of all groundwater samples in both seasons reveals that the groundwater chemistry of the area is controlled by silicate minerals weathering. The strong correlation of Ca2+ with Mg2+ in the dry season, and Ca2+ with HCO3- and Na+ with HCO3- in the wet season could also be an indication of silicate weathering and ion exchange processes. The impact of anthropogenic practices on groundwater chemistry is also seen from the strong correlation of Ca2+ with Cl-, NO3-, PO43- and F-, NO2- with K+, Mg2+, and PO43- , PO43- with F- , and NO3- with Na+, Cl-, HCO3- . The negative values of chloro-alkaline indices in both seasons indicate base-exchange reaction where an indirect exchange of Ca2+ and Mg2+ of the water with Na+ and K+ of the host rock occurs. Saturation indices results for the wet season show that the groundwater is under-saturated with respect to calcite, aragonite, dolomite, gypsum, and anhydrite. In the dry season, however, some of the waters are oversaturated with respect to calcite and aragonite. To sum up, the groundwater quality of the study area is controlled by geological processes and anthropogenic effects.

Enzymatic and Chemical Syntheses of Vacor Analogs of Nicotinamide Riboside, NMN and NAD

It has recently been demonstrated that the rat poison vacor interferes with mammalian NAD metabolism, because it acts as a nicotinamide analog and is converted by enzymes of the NAD salvage pathway. Thereby, vacor is transformed into the NAD analog vacor adenine dinucleotide (VAD), a molecule that causes cell toxicity. Therefore, vacor may potentially be exploited to kill cancer cells. In this study, we have developed efficient enzymatic and chemical procedures to produce vacor analogs of NAD and nicotinamide riboside (NR). VAD was readily generated by a base-exchange reaction, replacing the nicotinamide moiety of NAD by vacor, catalyzed by Aplysia californica ADP ribosyl cyclase. Additionally, we present the chemical synthesis of the nucleoside version of vacor, vacor riboside (VR). Similar to the physiological NAD precursor, NR, VR was converted to the corresponding mononucleotide (VMN) by nicotinamide riboside kinases (NRKs). This conversion is quantitative and very efficient. Consequently, phosphorylation of VR by NRKs represents a valuable alternative to produce the vacor analog of NMN, compared to its generation from vacor by nicotinamide phosphoribosyltransferase (NamPT).

PROGRAMMED AXON DEATH EXECUTOR SARM1 IS A MULTI-FUNCTIONAL NAD(P)ASE WITH PROMINENT BASE EXCHANGE ACTIVITY, ALL REGULATED BY PHYSIOLOGICAL LEVELS OF NMN, NAD, NADP AND OTHER METABOLITES

SARM1 is an NAD glycohydrolase and TLR adapter with an essential, prodegenerative role in programmed axon death (Wallerian degeneration). It has low basal NADase activity that becomes strongly activated by NAD precursor NMN. Very high levels of NAD oppose this activation, competing for the same allosteric site on SARM1′s regulatory ARM domain. Injury or diseases that deplete axons of NMNAT2, an essential enzyme converting NMN to NAD, cause SARM1 activation. The resulting NAD degradation by SARM1, combined with loss of NAD synthesis by NMNAT2, causes rapid depletion of axonal NAD. This NAD loss is widely assumed to mediate axon death and is consequently a key focus for therapeutic strategies for axonopathies. However, like other NAD(P) glycohydrolases, SARM1 has additional enzyme activities whose contributions, consequences and regulation need to be fully understood. Here, we compare the multiple actions and regulation of recombinant human SARM1 with those of two other NAD(P) glycohydrolases, human CD38 and Aplysia californica ADP ribosyl cyclase. We find that SARM1 has the highest transglycosidation (base exchange) activity of these enzymes at neutral pH and with some bases this dominates NAD(P) hydrolysis and cyclisation. Moreover, like its NADase and NADPase reactions, SARM1-mediated base exchange at neutral pH is activated by increases in the NMN:NAD ratio, which we show for the first time can act in the presence of physiological levels of both metabolites. We establish that SARM1 base exchange is the most likely physiological source of calcium mobilizing agent NaADP, and potentially of other NAD(P) analogues, which could contribute to axon and cell death. We also identify regulatory effects of free pyridine bases, of NADP and of nicotinic acid riboside (NaR) on SARM1 that represent further therapeutic opportunities. These data will help to pinpoint which of the multiple functions of SARM1 is responsible for axon degeneration and how it can be optimally targeted to block axon degeneration in disease.

التباين الكمي والنوعي لخصائص المياه الجوفية في ناحية الدجيلي

تناولت دراسة البحث التباين الكمي والنوعي للمياه الجوفية في ناحية الدجيلي ضمن محافظة واسط. من خلال اختيار ((10 آبار موزعة في منطقة الدراسة وتحليل مياهها كيميائياً وفيزيائياً لشهر نيسان لعام . 2019 وبينت النتائج تباين في الخصائص النوعية للمياه لاختلاف مواقعها إذ تتراوح قيمة التوصيلية الكهربائية ( (ECبين (1071-7274) us/cm.وتتراح قيمة امتزاز الصوديوم بين (103-3.33) مليمكافيء/لتر. كما أظهرت النتائج اختلاف قيم الايونات موقعياً لكل المؤشرات المدروسة إذ تراوحت قيم التوصيل الكهربائي بين (1071-7274) us/cmوتراوحت قيم نسبة المغنيسيوم (mg) ما بين ( (54-99ملغرام/لتر.اما الاملاح الذائبة الكلية (TDS) فقد تراوحت قيمتها بين (998-1691 ) ملغرام /لتر.والكلورايد (CL) تراوحت قيمه بين (90-262) ملغرام/لتر. وهناك ايضاً اختلافات موقعية لكل المؤشرات المدروسة وفقاً لاستعمال مياه الابار والظروف المحيطة بها أظهرت قيم العناصر لعينات المياه صلاحيتها لأغراض الشرب. كما تم اعتماد تقييم مدى صلاحية المياه للري على المتغيرات الهيدروكميائية المتمثلة بالأملاح المذابة ونسبة الصوديوم إلى الكالسيوم والبيكاربونات إلى الكالسيوم والمغنسيوم على كلاً من النبات والتربة ويعتمد أيضاً على نسبة امتزاز الصوديوم (SAR) وعلى كاربونات الصوديوم المتبقية (RSC) وهي من المعايير الأكثر أهمية في جودة المياه . وقد أُستخدم ايضاً مخطط ويلكوكس ((,1954 wilicox)) لتصنيف المياه الجوفية لاغراض الري يتم إعداده بوساطة رسم النسبة المئوية الصوديوم (Na%) مقابل رسم التوصيلة الكهربائية (EC) وتبين بأن ( (90%من المواقع تقع ضمن الفئة الجيدة الى الممتازة وما نسبته( (10%منها تقع ضمن الفئة الغير ملائمة. فضلاً عن كل من المؤشرات الهيدروجيوكيميائية المتمثلة بنسبة امتزاز الصوديوم ((SAR)) ومؤشر التبادل القاعدي ( (R1) Base-exchange index) وتصنيف المياه من حيث النشأة (Meteoric genesis index (R2)). وهناك أيضاً معاييراستخدمت لتقييم المياه الجوفية وذلك بحساب (Na%, P1,). ولتقييم المياه لأغراض الري واظهرت النتائج بأن معظم عينات المياه الجوفية صالحة للري. أما بالنسبة الى صلاحية مياه الابار للاستخدام الحيواني قد استخدم تصنيف (Altoviski, 1962) الذي يعتمد على تراكيز الأيونات الرئيسة الموجبة والسالبة والأملاح الذائبة والعسرة الكلية فقد تبين بأن جميع عينات المياه ولكل المواقع تقع ضمن الفئة الجيدة جداً حسب المحددات العالمية

Substrate-Dependent Sensitivity of SIRT1 to Nicotinamide Inhibition

SIRT1 is the most extensively studied human sirtuin with a broad spectrum of endogenous targets. It has been implicated in the regulation of a myriad of cellular events, such as gene transcription, mitochondria biogenesis, insulin secretion as well as glucose and lipid metabolism. From a mechanistic perspective, nicotinamide (NAM), a byproduct of a sirtuin-catalyzed reaction, reverses a reaction intermediate to regenerate NAD+ through “base exchange”, leading to the inhibition of the forward deacetylation. NAM has been suggested as a universal sirtuin negative regulator. Sirtuins have evolved different strategies in response to NAM regulation. Here, we report the detailed kinetic analysis of SIRT1-catalyzed reactions using endogenous substrate-based synthetic peptides. A novel substrate-dependent sensitivity of SIRT1 to NAM inhibition was observed. Additionally, SIRT1 demonstrated pH-dependent deacetylation with normal solvent isotope effects (SIEs), consistent with proton transfer in the rate-limiting step. Base exchange, in contrast, was insensitive to pH changes with no apparent SIEs, indicative of lack of proton transfer in the rate-limiting step. Consequently, NAM inhibition was attenuated at a high pH in proteated buffers. Our study provides new evidence for “activation by de-repression” as an effective sirtuin activation strategy.

Assessment of groundwater quality for drinking and irrigation purpose using hydrochemical studies in Dera Bassi town and its surrounding agricultural area of Dera Bassi Tehsil of Punjab, India

Present research aims to assess the suitability of groundwater of Dera Bassi town (Punjab) and its surrounding agricultural area for drinking as well as irrigation purpose. Thirty groundwater samples were collected (in February 2020) and analyzed for various physicochemical parameters. Results of physicochemical analysis were compared with Indian (IS 10500:2012) as well as WHO (2006) standards to ascertain the suitability of the groundwater samples for drinking purpose, and it has been found that results for almost all the parameters except alkalinity (at few sites) are within the permissible limit. The pattern of ionic dominance was observed in the order of Ca2+ > Mg2+ > Na+ > K+ for cations and Cl− > NO3− > SO42− > F− for anions. Further, according to the observed Kelly’s ratio, sodium adsorption ratio, sodium percentage, corrosivity ratio and permeability index, the groundwater samples were found to be fit for irrigation purpose. However, the magnesium ratio and residual sodium carbonate revealed that groundwater of the area under study is not fit for irrigation purpose at some sites. The plot of SAR values versus EC values in the US Salinity Laboratory diagram revealed that the majority of the samples fall under water type C3-S1 (high salinity—low SAR) and 36.77% samples fall under water type C2-S1 (medium salinity—low SAR). Gibb’s diagram revealed that all samples fall under rock dominance category. The values of index of base exchange (CAI 1 and CAI 2) indicate that both direct ion and reverse ion exchange processes are taking place in the region.