The genetics of blood pressure regulation and its target organs from association studies in 342,415 individuals

To dissect the genetic architecture of blood pressure and assess effects on target-organ damage, we analyzed 128,272 SNPs from targeted and genome-wide arrays in 201,529 individuals of European ancestry and genotypes from an additional 140,886 individuals were used for validation. We identified 66 blood pressure loci, of which 17 were novel and 15 harbored multiple distinct association signals. The 66 index SNPs were enriched for cis-regulatory elements, particularly in vascular endothelial cells, consistent with a primary role in blood pressure control through modulation of vascular tone across multiple tissues. The 66 index SNPs combined in a risk score showed comparable effects in 64,421 individuals of non-European descent. The 66-SNP blood pressure risk score was significantly associated with target-organ damage in multiple tissues, with minor effects in the kidney. Our findings expand current knowledge of blood pressure pathways and highlight tissues beyond the classic renal system in blood pressure regulation

Establishment of the implication of α- and β-amylases and α-glucan phosphorylases during starch degradation in Arabidopsis thaliana leaf

Différentes classes d’enzymes hydrolytiques (α- et β-amylases) et phosphorolytiques (amidon-phosphorylases) des α-glucanes sont impliquées dans le métabolisme de l’amidon dans la feuille d’Arabidopsis thaliana. Pas moins de 9 β-amylases, 3 α-amylases et 2 glucane-phosphorylases ont été répertoriées dans le génome de cette plante. Afin de leur attribuer une fonction précise, une étude phénotypique complète de lignées mutantes pour les formes plastidiales de ces enzymes a été menée au cours de ce travail. Chaque isoforme d’amylase a également été croisée avec un double mutant d’enzymes de branchement, be2- be3-, qui est totalement dépourvu d’amidon et accumule du maltose de manière inhabituelle. Afin de préciser l’implication de chaque forme d’amylase pour la production de ce maltose, le contenu en maltose des triples mutants a été analysé. Nos résultats nous permettent de conforter l’hypothèse d’une fonction de régulation de BAM4. Les perturbations observées dans les mutants bam1- et bam8- montrent l’importance de ces enzymes dans le métabolisme de l’amidon. Enfin, les résultats obtenus avec le mutant aam3- ne nous révèlent rien de sa fonction. L’analyse de l’α-glucane phosphorylase plastidiale PHS1 a été couplée à celle du mutant ss4- (une forme d’amidon synthétase soluble) et du double mutant ss4- phs1-. En effet, on observe au sein de ce double mutant des grains d’une taille 4 à 5 fois supérieure à ceux de la souche sauvage ainsi qu’une très forte augmentation de la quantité d’amidon. Les résultats nous indiquent que PHS1 est impliquée dans la dégradation de l’amidon, n’attaquant pas le grain natif, et qu’elle est similaire à ses homologues des plantes supérieures.Different classes of α-glucans hydrolytic (α- and β-amylases) and phosphorolytic enzymes are implicated in starch metabolism in Arabidopsis thaliana leaves. At least, 9 β-amylases, 3 α-amylases and 2 α-glucan phosphorylases are listed in this plant genome. In order to allocate them a precise function, a complete phenotypic study of mutant lines for plastidial forms of these enzymes was investigated. Each isoform of amylase studied was crossed with a double mutant of branching enzymes, be2- be3-, wich is free of starch and accumulating maltose which is unusual in this plant. In order to specify the implication of each form of amylase for the production of maltose in the be2- be3- mutant, maltose content of the triple mutants was analyzed. Our results allow us to strengthen the hypothesis of a regulating function of BAM4. Alterations observed in mutants bam1- and bam8- show us importance of these enzymes in starch metabolism. Finally, results obtained from analysis of aam3- mutant don’t reveal anything about its function. Analysis of plastidial α-glucan phosphorylase PHS1 was coupled with that of the mutant ss4- (a form of soluble starch synthase) and the double mutant ss4- phs1-. In fact, in this double mutant we observed starch granules 4 to 5 fold bigger than those of the wild-type strain and a strong increase of starch content. Results obtained show that PHS1 is implicated in starch degradation, don’t breaking native granule directly, and that it is similar to phosphorylases of land plants

Établissement de l'implication des a- et b-amylases et des a-glucanes phosphorylases au cours de la dégradation de l'amidon dans la feuille d'Arabidopsis thaliana

Différentes classes d enzymes hydrolytiques (a- et b-amylases) et phosphorolytiques (amidon-phosphorylases) des a-glucanes sont impliquées dans le métabolisme de l amidon dans la feuille d Arabidopsis thaliana. Pas moins de 9 b-amylases, 3 a-amylases et 2 glucane-phosphorylases ont été répertoriées dans le génome de cette plante. Afin de leur attribuer une fonction précise, une étude phénotypique complète de lignées mutantes pour les formes plastidiales de ces enzymes a été menée au cours de ce travail. Chaque isoforme d amylase a également été croisée avec un double mutant d enzymes de branchement, be2- be3-, qui est totalement dépourvu d amidon et accumule du maltose de manière inhabituelle. Afin de préciser l implication de chaque forme d amylase pour la production de ce maltose, le contenu en maltose des triples mutants a été analysé. Nos résultats nous permettent de conforter l hypothèse d une fonction de régulation de BAM4. Les perturbations observées dans les mutants bam1- et bam8- montrent l importance de ces enzymes dans le métabolisme de l amidon. Enfin, les résultats obtenus avec le mutant aam3- ne nous révèlent rien de sa fonction. L analyse de l a-glucane phosphorylase plastidiale PHS1 a été couplée à celle du mutant ss4- (une forme d amidon synthétase soluble) et du double mutant ss4- phs1-. En effet, on observe au sein de ce double mutant des grains d une taille 4 à 5 fois supérieure à ceux de la souche sauvage ainsi qu une très forte augmentation de la quantité d amidon. Les résultats nous indiquent que PHS1 est impliquée dans la dégradation de l amidon, n attaquant pas le grain natif, et qu elle est similaire à ses homologues des plantes supérieures.Different classes of a-glucans hydrolytic (a- and b-amylases) and phosphorolytic enzymes are implicated in starch metabolism in Arabidopsis thaliana leaves. At least, 9 b-amylases, 3 a-amylases and 2 a-glucan phosphorylases are listed in this plant genome. In order to allocate them a precise function, a complete phenotypic study of mutant lines for plastidial forms of these enzymes was investigated. Each isoform of amylase studied was crossed with a double mutant of branching enzymes, be2- be3-, wich is free of starch and accumulating maltose which is unusual in this plant. In order to specify the implication of each form of amylase for the production of maltose in the be2- be3- mutant, maltose content of the triple mutants was analyzed. Our results allow us to strengthen the hypothesis of a regulating function of BAM4. Alterations observed in mutants bam1- and bam8- show us importance of these enzymes in starch metabolism. Finally, results obtained from analysis of aam3- mutant don t reveal anything about its function. Analysis of plastidial a-glucan phosphorylase PHS1 was coupled with that of the mutant ss4- (a form of soluble starch synthase) and the double mutant ss4- phs1-. In fact, in this double mutant we observed starch granules 4 to 5 fold bigger than those of the wild-type strain and a strong increase of starch content. Results obtained show that PHS1 is implicated in starch degradation, don t breaking native granule directly, and that it is similar to phosphorylases of land plants.LILLE1-Bib. Electronique (590099901) / SudocSudocFranceF

Further Evidence for the Mandatory Nature of Polysaccharide Debranching for the Aggregation of Semicrystalline Starch and for Overlapping Functions of Debranching Enzymes in Arabidopsis Leaves1[W]

Four isoforms of debranching enzymes are found in the genome of Arabidopsis (Arabidopsis thaliana): three isoamylases (ISA1, ISA2, and ISA3) and a pullulanase (PU1). Each isoform has a specific function in the starch pathway: synthesis and/or degradation. In this work we have determined the levels of functional redundancy existing between these isoforms by producing and analyzing different combinations of mutations: isa3-1 pu1-1, isa1-1 isa3-1, and isa1-1 isa3-1 pu1-1. While the starch content strongly increased in the isa3-1 pu1-1 double mutant, the latter decreased by over 98% in the isa1-1 isa3-1 genotype and almost vanished in triple mutant combination. In addition, whereas the isa3-1 pu1-1 double mutant synthesizes starch very similar to that of the wild type, the structure of the residual starch present either in isa1-1 isa3-1 or in isa1-1 isa3-1 pu1-1 combination is deeply affected. In the same way, water-soluble polysaccharides that accumulate in the isa1-1 isa3-1 and isa1-1 isa3-1 pu1-1 genotypes display strongly modified structure compared to those found in isa1-1. Taken together, these results show that in addition to its established function in polysaccharide degradation, the activity of ISA3 is partially redundant to that of ISA1 for starch synthesis. Our results also reveal the dual function of pullulanase since it is partially redundant to ISA3 for degradation and to ISA1 for synthesis. Finally, x-ray diffraction analyses suggest that the crystallinity and the presence of the 9- to 10-nm repetition pattern in starch precisely depend on the level of debranching enzyme activity

Humic Substances Alter Ammonia Production and the Microbial Populations Within a RUSITEC Fed a Mixed Hay – Concentrate Diet

Humic substances are a novel feed additive which may have the potential to mitigate enteric methane (CH4) production from ruminants as well as enhance microbial activity in the rumen. The aim of this study was to examine the effects of humic substances on fermentation characteristics and microbial communities using the rumen stimulation technique (RUSITEC). The experiment was conducted as a completely randomized design with 3 treatments duplicated in 2 runs (a 15-day period each run) with 2 replicates per run. Treatments consisted of a control diet (forage:concentrate; 60:40) without humic substances or humic substances added at either 1.5 g/d or 3.0 g/d. Dry matter disappearance, pH, fermentation parameters and gas production were measured from day 8 to 15. Samples for microbial profiling were taken on day 5, 10, and 15 using the digested feed bags for solid- associated microbes (SAM) and fermenter fluid for liquid- associated microbes (LAM). The inclusion of humic substances had no effect (P ≥ 0.19) on DM disappearance, pH or the concentrations of VFA. The production of NH3 was linearly decreased (P = 0.04) with increasing levels of humic substances in the diet. There was no effect (P ≥ 0.43) of humic substances on total gas, CO2 or CH4 production. The number of OTUs was significantly reduced in the 3.0 g/d treatment compared to the control on d 10 and 15; however, the microbial community structure was largely unaffected (P > 0.05). In the SAM samples, the genera Lachnospiraceae XPB1014 group, Succiniclasticum, and Fibrobacter were reduced in the 3.0 g/d treatment and Anaeroplasma, Olsenella, and Pseudobutyrivibrio were increased on day 5, 10, and 15. Within the LAM samples, Christensenellaceae R-7 and Succiniclasticum were the most differentially abundant genera between the control and 3.0 g/d HS treatment samples (P < 0.05). This study highlights the potential use of humic substances as a natural feed additive which may play a role in nitrogen metabolism without negatively affecting the ruminal microbiota

Genetic dissection of floridean starch synthesis in the cytosol of the model dinoflagellate Crypthecodinium cohnii

Starch defines an insoluble semicrystalline form of storage polysaccharides restricted to Archaeplastida (red and green algae, land plants, and glaucophytes) and some secondary endosymbiosis derivatives of the latter. While green algae and land-plants store starch in plastids by using an ADP-glucose-based pathway related to that of cyanobacteria, red algae, glaucophytes, cryptophytes, dinoflagellates, and apicomplexa parasites store a similar type of polysaccharide named floridean starch in their cytosol or periplast. These organisms are suspected to store their floridean starch from UDP-glucose in a fashion similar to heterotrophic eukaryotes. However, experimental proof of this suspicion has never been produced. Dinoflagellates define an important group of both photoautotrophic and heterotrophic protists. We now report the selection and characterization of a low starch mutant of the heterotrophic dinoflagellate Crypthecodinium cohnii. We show that the sta1-1 mutation of C. cohnii leads to a modification of the UDP-glucose-specific soluble starch synthase activity that correlates with a decrease in starch content and an alteration of amylopectin structure. These experimental results validate the UDP-glucose-based pathway proposed for floridean starch synthesis

Image_1_Humic Substances Alter Ammonia Production and the Microbial Populations Within a RUSITEC Fed a Mixed Hay – Concentrate Diet.PDF

<p>Humic substances are a novel feed additive which may have the potential to mitigate enteric methane (CH₄) production from ruminants as well as enhance microbial activity in the rumen. The aim of this study was to examine the effects of humic substances on fermentation characteristics and microbial communities using the rumen stimulation technique (RUSITEC). The experiment was conducted as a completely randomized design with 3 treatments duplicated in 2 runs (a 15-day period each run) with 2 replicates per run. Treatments consisted of a control diet (forage:concentrate; 60:40) without humic substances or humic substances added at either 1.5 g/d or 3.0 g/d. Dry matter disappearance, pH, fermentation parameters and gas production were measured from day 8 to 15. Samples for microbial profiling were taken on day 5, 10, and 15 using the digested feed bags for solid- associated microbes (SAM) and fermenter fluid for liquid- associated microbes (LAM). The inclusion of humic substances had no effect (P ≥ 0.19) on DM disappearance, pH or the concentrations of VFA. The production of NH₃ was linearly decreased (P = 0.04) with increasing levels of humic substances in the diet. There was no effect (P ≥ 0.43) of humic substances on total gas, CO₂ or CH₄ production. The number of OTUs was significantly reduced in the 3.0 g/d treatment compared to the control on d 10 and 15; however, the microbial community structure was largely unaffected (P > 0.05). In the SAM samples, the genera Lachnospiraceae XPB1014 group, Succiniclasticum, and Fibrobacter were reduced in the 3.0 g/d treatment and Anaeroplasma, Olsenella, and Pseudobutyrivibrio were increased on day 5, 10, and 15. Within the LAM samples, Christensenellaceae R-7 and Succiniclasticum were the most differentially abundant genera between the control and 3.0 g/d HS treatment samples (P < 0.05). This study highlights the potential use of humic substances as a natural feed additive which may play a role in nitrogen metabolism without negatively affecting the ruminal microbiota.</p

Image_3_Tucumã Oil Shifted Ruminal Fermentation, Reducing Methane Production and Altering the Microbiome but Decreased Substrate Digestibility Within a RUSITEC Fed a Mixed Hay – Concentrate Diet.TIFF

<p>Tucumã oil is sourced from the fruit pulp of the tucumã tree and contains high concentrations of unsaturated fatty acids and carotenoids. Due to these properties it may have the potential to decrease enteric methane (CH₄) from ruminants when included in the diet. The objective of this study was to determine the effect of oil mechanically extracted from the fruit pulp of tucumã on fermentation characteristics, CH₄ production and the microbial community using the rumen stimulation technique. Treatments consisted of a control diet (forage:concentrate; 70:30), and tucumã oil included at 0.5 or 1.0% (v/v). Addition of tucumã oil linearly decreased (P < 0.01) dry matter disappearance. Total gas (mL/d) and carbon dioxide (CO₂) production (mL/d, mL/g DM) were unaffected (P ≥ 0.36) to increasing addition of tucumã oil where 0.5% (v/v) of Tucumã oil numerically increased both variables. Acetate and butyrate percentages of total VFA were linearly decreased (P ≤ 0.01) and propionate and valerate percentages of total VFA were linearly increased (P < 0.01) by increasing concentrations of tucumã oil added to the substrate. The ratio of acetate to propionate was linearly decreased (P < 0.01) with increasing concentration of tucumã oil. Methane production (mL/d) was linearly decreased (P = 0.04) with increasing addition of tucumã oil to the substrate. Tucumã oil reduced the bacterial richness and diversity when included at 1.0% (v/v) in both solid- and liquid- associated microbes. The abundance of the genera Fibrobacter and Rikenellaceae RC9 gut group were decreased and Pyramidobacter, Megasphaera, Anaerovibrio, and Selenomonas were enriched by the addition of 1.0% tucumã oil. In conclusion, tucumã oil resulted in the favorable shift in fermentation products away from acetate toward propionate, decreasing the production of CH₄ when tucumã oil was included at 1.0% (v/v), however, substrate digestibility was also inhibited. The rumen microbiota was also altered by the addition of tucumã oil.</p

Image_4_Tucumã Oil Shifted Ruminal Fermentation, Reducing Methane Production and Altering the Microbiome but Decreased Substrate Digestibility Within a RUSITEC Fed a Mixed Hay – Concentrate Diet.TIFF

<p>Tucumã oil is sourced from the fruit pulp of the tucumã tree and contains high concentrations of unsaturated fatty acids and carotenoids. Due to these properties it may have the potential to decrease enteric methane (CH₄) from ruminants when included in the diet. The objective of this study was to determine the effect of oil mechanically extracted from the fruit pulp of tucumã on fermentation characteristics, CH₄ production and the microbial community using the rumen stimulation technique. Treatments consisted of a control diet (forage:concentrate; 70:30), and tucumã oil included at 0.5 or 1.0% (v/v). Addition of tucumã oil linearly decreased (P < 0.01) dry matter disappearance. Total gas (mL/d) and carbon dioxide (CO₂) production (mL/d, mL/g DM) were unaffected (P ≥ 0.36) to increasing addition of tucumã oil where 0.5% (v/v) of Tucumã oil numerically increased both variables. Acetate and butyrate percentages of total VFA were linearly decreased (P ≤ 0.01) and propionate and valerate percentages of total VFA were linearly increased (P < 0.01) by increasing concentrations of tucumã oil added to the substrate. The ratio of acetate to propionate was linearly decreased (P < 0.01) with increasing concentration of tucumã oil. Methane production (mL/d) was linearly decreased (P = 0.04) with increasing addition of tucumã oil to the substrate. Tucumã oil reduced the bacterial richness and diversity when included at 1.0% (v/v) in both solid- and liquid- associated microbes. The abundance of the genera Fibrobacter and Rikenellaceae RC9 gut group were decreased and Pyramidobacter, Megasphaera, Anaerovibrio, and Selenomonas were enriched by the addition of 1.0% tucumã oil. In conclusion, tucumã oil resulted in the favorable shift in fermentation products away from acetate toward propionate, decreasing the production of CH₄ when tucumã oil was included at 1.0% (v/v), however, substrate digestibility was also inhibited. The rumen microbiota was also altered by the addition of tucumã oil.</p