Graphical AbstractHighlights d Blocking ETC or lactate production reduces cytosolic NAD + / NADH and increases HUFAs d HUFA synthesis by D5D and D6D is a mechanism for glycolytic NAD + recycling d D5D-and D6D-mediated NAD + regeneration can be acutely adaptive in vivo d SLC16A11 and FADS1-3 may influence metabolic risk via impact on cytosolic NAD + /NADH SUMMARY The reactions catalyzed by the delta-5 and delta-6 desaturases (D5D/D6D), key enzymes responsible for highly unsaturated fatty acid (HUFA) synthesis, regenerate NAD + from NADH. Here, we show that D5D/D6D provide a mechanism for glycolytic NAD + recycling that permits ongoing glycolysis and cell viability when the cytosolic NAD + /NADH ratio is reduced, analogous to lactate fermentation. Although lesser in magnitude than lactate production, this desaturase-mediated NAD + recycling is acutely adaptive when aerobic respiration is impaired in vivo.Notably, inhibition of either HUFA synthesis or lactate fermentation increases the other, underscoring their interdependence. Consistent with this, a type 2 diabetes risk haplotype in SLC16A11 that reduces pyruvate transport (thus limiting lactate production) increases D5D/D6D activity in vitro and in humans, demonstrating a chronic effect of desaturase-mediated NAD + recycling. These findings highlight key biologic roles for D5D/D6D activity independent of their HUFA end products and expand the current paradigm of glycolytic NAD + regeneration.
The complete genome of the solvent tolerant Staphylococcus warneri SG1 was recently published. This Gram-positive bacterium is tolerant to a large spectrum of organic solvents including short-chain alcohols, alkanes, esters and cyclic aromatic compounds. In this study, we applied a two-dimensional liquid chromatography (2D-LC) mass spectrometry (MS) shotgun approach, in combination with quantitative 2-MEGA (dimethylation after guanidination) isotopic labeling, to compare the proteomes of SG1 grown under butanol-free and butanol-challenged conditions. In total, 1585 unique proteins (representing 65% of the predicted open reading frames) were identified, covering all major metabolic pathways. Of the 967 quantifiable proteins by 2-MEGA labeling, 260 were differentially expressed by at least 1.5-fold. These proteins are involved in energy metabolism, oxidative stress response, lipid and cell envelope biogenesis, or have chaperone functions. We also applied differential isotope labeling LC-MS to probe metabolite changes in key metabolic pathways upon butanol stress. This is the first comprehensive proteomic and metabolomic study of S. warneri SG1 and presents an important step toward understanding its physiology and mechanism of solvent tolerance.
Purpose -The purpose of the paper is to marshal the carbon sources, and explore a computational model to calculate the buildings' carbon emissions by using building information modeling (BIM) techniques. The study aims to integrate the BIM techniques with the carbon emission and energy analysis tools, which can provide a more exact quantification result. Design/methodology/approach -To define the scope of this study, several standards or regulations have been comparatively analyzed. The BIM technique has also been used to establish the computational model of carbon emissions, including the calculation principle, the basic database, and each process of modeling. Finally, a case study is given to test the theoretical study. Findings -The paper provides a quantitative calculation method for the carbon emissions of buildings, and suggests an approach to integrate the BIM techniques with the low carbon research. This allows the quantity of material consumption and carbon emission to be calculated in real time during the whole construction process. Research limitations/implications -Because of the chosen American database, the calculation results may lack generalizability. Therefore, the approach of establishing a universal database of carbon emission coefficients will be the next key point. Practical implications -As this research shows, there is a need for an advanced calculation method to evaluate the buildings' carbon emission exactly by BIM techniques, which also provides a basis to establish the regulation of carbon transaction tax in the future. Originality/value -This paper fulfils an identified need to calculate the carbon emission during the buildings' construction stage, so that better decisions can be made to optimize the construction plan and choose the low emission materials properly.
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