Genome Wide Analysis of GH Gene Family Reveals Vvgh9 Positively Regulates Sugar Accumulation under Low Sugar Content in Grape

Sugar content directly affects grape (Vitis vinifera L.) berry quality and the resulting wine. Therefore, it is of great importance to study and explore novel genes that affect sugar accumulation in grapes. Glycosyl hydrolases (GHs) are key enzymes hydrolyzing polysaccharides into monosaccharides and play important roles in the regulation of carbohydrate metabolism. Nevertheless, the impact of GHs on the regulation of sugar accumulation in plants has rarely been investigated. In this study, we identified 11 putative GH genes in grapevines by phylogeny analysis. RNA-seq and quantitative real-time PCR results demonstrated that the expression level of VvGH9 was higher during the fruit set stage, which had lower sugar content than the véraison and ripe stages. Treatment of grape berries with exogenous sugar two weeks before véraison revealed that VvGH9 was rapidly induced by sucrose, fructose, and glucose. When ‘41B’ calli was treated with different concentrations of glucose, VvGH9 expression increased at first and then decreased with the increase of glucose concentration. Overexpression of VvGH9 in grape calli and tomatoes also confirmed that this gene could contribute to sugar accumulation. All the above results demonstrated that VvGH9 promotes sugar accumulation under low sugar content in plants.

Protein-Metabolite Interactomics Reveals Novel Regulation of Carbohydrate Metabolism

Metabolism is highly interconnected and also has profound effects on other cellular processes. However, the interactions between metabolites and proteins that mediate this connectivity are frequently low affinity and difficult to discover, hampering our understanding of this important area of cellular biochemistry. Therefore, we developed the MIDAS platform, which can identify protein-metabolite interactions with great sensitivity. We analyzed 33 enzymes from central carbon metabolism and identified 830 protein-metabolite interactions that were mostly novel, but also included known regulators, substrates, products and their analogs. We validated previously unknown interactions, including two atomic-resolution structures of novel protein-metabolite complexes. We also found that both ATP and long-chain fatty acyl-CoAs inhibit lactate dehydrogenase A (LDHA), but not LDHB, at physiological concentrations in vitro. Treating cells with long-chain fatty acids caused a loss of pyruvate/lactate interconversion, but only in cells reliant on LDHA. We propose that these regulatory mechanisms are part of the metabolic connectivity that enables survival in an ever-changing nutrient environment, and that MIDAS enables a broader and deeper understanding of that network.

The Crosstalk of Melatonin and Hydrogen Sulfide Determines Photosynthetic Performance by Regulation of Carbohydrate Metabolism in Wheat under Heat Stress

Photosynthesis is a pivotal process that determines the synthesis of carbohydrates required for sustaining growth under normal or stress situation. Stress exposure reduces the photosynthetic potential owing to the excess synthesis of reactive oxygen species that disturb the proper functioning of photosynthetic apparatus. This decreased photosynthesis is associated with disturbances in carbohydrate metabolism resulting in reduced growth under stress. We evaluated the importance of melatonin in reducing heat stress-induced severity in wheat (Triticum aestivum L.) plants. The plants were subjected to 25 °C (optimum temperature) or 40 °C (heat stress) for 15 days at 6 h time duration and then developed the plants for 30 days. Heat stress led to oxidative stress with increased production of thiobarbituric acid reactive substances (TBARS) and hydrogen peroxide (H2O2) content and reduced accrual of total soluble sugars, starch and carbohydrate metabolism enzymes which were reflected in reduced photosynthesis. Application of melatonin not only reduced oxidative stress through lowering TBARS and H2O2 content, augmenting the activity of antioxidative enzymes but also increased the photosynthesis in plant and carbohydrate metabolism that was needed to provide energy and carbon skeleton to the developing plant under stress. However, the increase in these parameters with melatonin was mediated via hydrogen sulfide (H2S), as the inhibition of H2S by hypotaurine (HT; H2S scavenger) reversed the ameliorative effect of melatonin. This suggests a crosstalk of melatonin and H2S in protecting heat stress-induced photosynthetic inhibition via regulation of carbohydrate metabolism.

The Crosstalk of Melatonin and Hydrogen Sulfide Determines Photosynthetic Performance by Regulation of Carbohydrate Metabolism in Wheat under Heat Stress

Photosynthesis is a pivotal process that determines the synthesis of carbohydrates required for sustaining growth under normal or stress situation. Stress exposure reduces the photosynthetic potential owing to the excess synthesis of reactive oxygen species that disturb the proper functioning of photosynthetic apparatus. This decreased photosynthesis is associated with disturbances in carbohydrate metabolism resulting in reduced growth under stress. We evaluated the importance of melatonin in reducing heat stress-induced severity in wheat plants (Triticum aestivum L.). The plants were subjected to 25 ˚C (optimum temperature) or 40 ˚C (heat stress) for 15 days at 6 hours time duration and then developed the plants for 30 days. Heat stress led to oxidative stress with increased production of TBARS and H2O2 content and reduced accrual of total soluble sugars, starch and carbohydrate metabolism enzymes which are reflected in reduced photosynthesis. Application of melatonin not only reduced oxidative stress through lowering TBARS and H2O2 content, through augmenting the activity of antioxidative enzymes but also increased the photosynthesis in plant and carbohydrate metabolism that is needed to provide energy and carbon skeleton to the developing plant under stress. However, the increase in these parameters with melatonin was mediated via hydrogen sulfide (H2S), as the inhibition of H2S by hypotaurine (HT; H2S inhibitor) reversed the ameliorative effect of melatonin. This suggests a crosstalk of melatonin and H2S in protecting heat stress-induced photosynthetic inhibition via regulation of carbohydrate metabolism.

INFLUENCE OF MARKERS OF ENERGETIC HOMEOSTASIS AND ADIPOKINES ON THE REGULATION OF CARBOHYDRATE METABOLISM IN PATIENTS WITH ACUTE MYOCARDIAL INFARCTION AND CONCOMITANT OBESITY

There have been reports on the effect of energy homeostasis markers and adipokines (FABP 4 and CTRP 3) on the development and course of cardiovascular disease in patients with concomitant obesity. The role of energy homeostasis and adipokines in the development of acute myocardial infarction and concomitant diseases is still insufficiently studied. The purpose of this work was to study the relationship between markers of energy homeostasis, adipokines and carbohydrate metabolism in patients with acute myocardial infarction and syntropic pathology. The study included 189 patients with acute myocardial infarction with and without obesity. The control group included 20 healthy individuals. Adropin, irisin, FABP 4, CTRP 3, insulin were determined by enzyme-linked immunosorbent assay. Mathematical computer processing of the findings obtained were performed using the software package "IBM SPPS Statistics 27.0" and Microsoft Office Excel. All groups of the patients were found to have increased levels of glucose, insulin, HOMA index compared with the control group (p˂0.05). The patients of all group demonstrated a decrease in adropine, irisin and CTRP 3 and an increase in FABP 4 when compared with the control group (p˂0.05). Analysis of the results points out the correlation between carbohydrate metabolism and the level of adropine, irisin, FABP 4, and CTRP 3 in all groups of the patients. Thus, the study has shown the influence of energy metabolism and adipokine system on carbohydrate metabolism in the patients with acute myocardial infarction depending on the presence and absence of obesity.

Drosophila melanogastersex peptide regulates mated female midgut morphology and physiology

Drosophila melanogasterfemales experience a large shift in energy homeostasis after mating to compensate for nutrient investment in egg production. To cope with this change in metabolism, mated females undergo widespread physiological and behavioral changes, including increased food intake and altered digestive processes. The mechanisms by which the female digestive system responds to mating remain poorly characterized. Here, we demonstrate that the seminal fluid protein Sex Peptide (SP) is a key modulator of female post-mating midgut growth and gene expression. SP is both necessary and sufficient to trigger post-mating midgut growth in females under normal nutrient conditions, and likely acting via its receptor, Sex Peptide Receptor (SPR). Moreover, SP is responsible for almost the totality of midgut transcriptomic changes following mating, including up-regulation of protein and lipid metabolism genes and down-regulation of carbohydrate metabolism genes. These changes in metabolism may help supply the female with the nutrients required to sustain egg production. Thus, we report a role for SP in altering female physiology to enhance reproductive output: Namely, SP triggers the switch from virgin to mated midgut state.