Alternative NAD(P)H dehydrogenase and alternative oxidase: proposed physiological roles in animals

The electron transport systems in mitochondria of many organisms contain alternative respiratory enzymes distinct from those of the canonical respiratory system depicted in textbooks. Two of these enzymes, the alternative NADH dehydrogenase and the alternative oxidase, were of interest to a limited circle of researchers until they were envisioned as gene therapy tools for mitochondrial disease treatment. Recently, these enzymes were discovered in several animals. Here, we analyse the functioning of alternative NADH dehydrogenases and oxidases in different organisms. We propose that both enzymes ensure bioenergetic and metabolic flexibility during environmental transitions or other conditions which may compromise the operation of the canonical respiratory system. The electron transport systems in mitochondria of many organisms contain alternative respiratory enzymes distinct from those of the canonical respiratory system depicted in textbooks. Two of these enzymes, the alternative NADH dehydrogenase and the alternative oxidase, were of interest to a limited circle of researchers until they were envisioned as gene therapy tools for mitochondrial disease treatment. Recently, these enzymes were discovered in several animals. Here, we analyse the functioning of alternative NADH dehydrogenases and oxidases in different organisms. We propose that both enzymes ensure bioenergetic and metabolic flexibility during environmental transitions or other conditions which may compromise the operation of the canonical respiratory system

Alternative NAD(P)H dehydrogenase and alternative oxidase: proposed physiological roles in animals

The electron transport systems in mitochondria of many organisms contain alternative respiratory enzymes distinct from those of the canonical respiratory system depicted in textbooks. Two of these enzymes, the alternative NADH dehydrogenase and the alternative oxidase, were of interest to a limited circle of researchers until they were envisioned as gene therapy tools for mitochondrial disease treatment. Recently, these enzymes were discovered in several animals. Here, we analyse the functioning of alternative NADH dehydrogenases and oxidases in different organisms. We propose that both enzymes ensure bioenergetic and metabolic flexibility during environmental transitions or other conditions which may compromise the operation of the canonical respiratory system. The electron transport systems in mitochondria of many organisms contain alternative respiratory enzymes distinct from those of the canonical respiratory system depicted in textbooks. Two of these enzymes, the alternative NADH dehydrogenase and the alternative oxidase, were of interest to a limited circle of researchers until they were envisioned as gene therapy tools for mitochondrial disease treatment. Recently, these enzymes were discovered in several animals. Here, we analyse the functioning of alternative NADH dehydrogenases and oxidases in different organisms. We propose that both enzymes ensure bioenergetic and metabolic flexibility during environmental transitions or other conditions which may compromise the operation of the canonical respiratory system

Effects of Feeding with Non-Autoclaved and Autoclaved Fructose-Arginine Mixture on Stress Resistance of Drosophila Melanogaster

The diet of modern people includes fast food that leads to the development of obesity and related diseases. One of the reasons for the negative impact of such a diet is advanced glycation end products (AGEs), substances formed as a result of the interaction of amino acids with carbohydrates, especially under the influence of high temperature (the Maillard reaction). Once in the body, these substances lead to oxidative stress and inflammation, which in turn can accelerate aging process. Also, AGEs are involved in the development of metabolic syndrome, diabetes, cardiovascular disease, and cancer. However, mild oxidative stress can activate cellular defense systems and make cells more resistant to a stronger oxidative stress or other types of stress that is called hormesis or cross-tolerance. Our study shows an effect of non-autoclaved (FAMn) and autoclaved (FAMa) fructose-arginine mixtures on the body of fruit flies. In our study, we used the Drosophila melanogaster line w1118. Flies were grown on nutrient medium with the addition of different amounts of FAMn or FAMa to the final concentrations of reagents in a mixture of 10, 20 and 100 mM and maintained on the respective media until the second day of age. The flies were then used to determine physiological and biochemical parameters. The increase in absorbance at 294 nm and 420 nm and a decrease in fructose concentration in FAMa indicated that autoclaving of the fructose-arginine mixture led to caramelization of fructose and formation of Maillard products. The study showed that FAM in both forms did not affect lipid peroxide level, a marker of oxidative stress. Also, FAM in both forms did not affect the resistance of flies to hydrogen peroxide. However, FAMn, but not FAMa, increased the resistance of flies to sodium nitroprusside (SNP). This effect is likely caused by the presence of arginine, a substrate for NO-synthase, which may pre-adapt flies to •NO released from SNP. FAMn and FAMa at the concentration of 100 mM increased content of storage lipids, but decreased resistance of flies to starvation

Alternative NADH dehydrogenase extends lifespan and increases resistance to xenobiotics in Drosophila

Mitochondrial alternative NADH dehydrogenase (aNDH) was found to extend lifespan when expressed in the fruit fly. We have found that fruit flies expressing aNDH from Ciona intestinalis (NDX) had 17-71% lifespan prolongation on media with different protein-tocarbohydrate ratios except NDX-expressing males that had 19% shorter lifespan than controls on a high protein diet. NDX-expressing flies were more resistant to organic xenobiotics, 2,4-dichlorophenoxyacetic acid and alloxan, and inorganic toxicant potassium iodate, and partially to sodium molybdate treatments. On the other hand, NDX-expressing flies were more sensitive to catechol and sodium chromate. Enzymatic analysis showed that NDX-expressing males had higher glucose 6-phosphate dehydrogenase activity, whilst both sexes showed increased glutathione S-transferase activity.Peer reviewe

Alternative NADH dehydrogenase extends lifespan and increases resistance to xenobiotics in Drosophila (vol 147, pg 2311, 2020)

Correction to https://doi.org/10.1007/s10522-019-09849-8Peer reviewe

Insulin-Like Peptides Regulate Feeding Preference and Metabolism in Drosophila

Fruit flies have eight identified Drosophila insulin-like peptides (DILPs) that are involved in the regulation of carbohydrate concentrations in hemolymph as well as in accumulation of storage metabolites. In the present study, we investigated diet-dependent roles of DILPs encoded by the genes dilp1–5, and dilp7 in the regulation of insect appetite, food choice, accumulation of triglycerides, glycogen, glucose, and trehalose in fruit fly bodies and carbohydrates in hemolymph. We have found that the wild type and the mutant lines demonstrate compensatory feeding for carbohydrates. However, mutants on dilp2,3, dilp3, dilp5, and dilp7 showed higher consumption of proteins on high yeast diets. To evaluate metabolic differences between studied lines on different diets we applied response surface methodology. High nutrient diets led to a moderate increase in concentration of glucose in hemolymph of the wild type flies. Mutations on dilp genes changed this pattern. We have revealed that the dilp2 mutation led to a drop in glycogen levels independently on diet, lack of dilp3 led to dramatic increase in circulating trehalose and glycogen levels, especially at low protein consumption. Lack of dilp5 led to decreased levels of glycogen and triglycerides on all diets, whereas knockout on dilp7 caused increase in glycogen levels and simultaneous decrease in triglyceride levels at low protein consumption. Fruit fly appetite was influenced by dilp3 and dilp7 genes. Our data contribute to the understanding of Drosophila as a model for further studies of metabolic diseases and may serve as a guide for uncovering the evolution of metabolic regulatory pathways

Ciona intestinalis NADH dehydrogenase NDX confers stress-resistance and extended lifespan on Drosophila

Peer reviewe