Evolution of increased early-life fecundity but faster reproductive senescence in Drosophila melanogaster females through adaptation to chronic live-yeast deprivation

Dietary restriction is a common ecological challenge that limits reproduction. Yet only a few studies have explored adaptation under chronic protein deprivation. We subjected four replicate laboratory-adapted populations (YLB) of Drosophila melanogaster to a complete deprivation of live-yeast to mimic diet restricted ecology. In this insect, live-yeast is a critical source of protein that strongly affect reproductive output, especially in females. Following 24 generations of experimental evolution, compared to their matched controls (BL), females from YLB populations showed increase in reproductive output early in life, both in presence and absence of live-yeast. The observed increase in reproductive output was not associated with any accommodating alteration in average egg size; and development time, pre-adult survivorship, and body mass at eclosion of the progeny. Interestingly, adult lifespan was also found to be unaffected. However, YLB females were found to have a significantly faster rate of reproductive senescence albeit without any change in a measure of lifetime reproductive output. Taken together, adaptation to LYD ecology shows that reproductive output can evolve without affecting lifespan, suggesting that widely observed reproduction-survival trade-off is not universal. Populations can optimize fitness by fine tuning the scheduling of reproduction even when lifetime reproductive output is constrained.

Urinary Dopamine Excretion Rate Decreases during Acute Dietary Protein Deprivation and Is Associated with Increased Plasma Pancreatic Polypeptide Concentration

Background: Dopamine, a key neurotransmitter in the autonomic nervous system participating in the homeostatic balance between sympathetic and parasympathetic divisions, is involved in food intake regulation. Objective: We investigated whether dopamine is altered by acute fasting or overfeeding diets with varying macronutrient content. Design: Ninety-nine healthy subjects underwent 24-h dietary interventions including eucaloric feeding, fasting, and five different overfeeding diets in a crossover design. Overfeeding diets (200% of eucaloric requirements) included one diet with 3%-protein (low-protein high-fat overfeeding—LPF: 46%-fat), three diets with 20%-protein, and a diet with 30%-protein (44%-fat). Urine was collected for 24 h and urinary dopamine concentration was quantified by high-performance liquid chromatography. Plasma pancreatic polypeptide (PP) concentration, an indirect marker of parasympathetic activity, was measured prior to and after each diet after an overnight fast. Results: During 24-h of fasting, dopamine decreased on average by ~14% compared to eucaloric conditions, whereas PP increased by two-fold (both p < 0.001). Lower dopamine during 24-h fasting correlated with increased PP (r = −0.40, p < 0.001). Similarly, on average urinary dopamine decreased during LPF by 14% (p < 0.001) and lower dopamine correlated with increased PP (r = −0.31, p = 0.01). No changes in dopamine and PP concentrations were observed during other overfeeding diets (all p > 0.05). Conclusions: Dopamine concentrations decrease during short-term fasting and overfeeding with a low-protein diet. As both dietary conditions have in common protein deficit, the correlation between dopamine and PP suggests a compensatory mechanism underlying the shift from sympathetic to parasympathetic drive during dietary protein deprivation.

A translation repressor, 4E-BP1, regulates the triglyceride level in rat liver during protein deprivation

Protein deprivation has been shown to induce fatty liver in humans and animals, but the molecular mechanisms underlying such induction are largely unknown. Our previous studies have shown that a low-protein diet increases eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) protein and triglyceride (TG) levels in rat liver. 4E-BP1 is known to repress translation by binding to eIF4E. There is also evidence indicating that 4E-BP1 regulates lipid metabolism. Here, we examined the role of 4E-BP1 on TG accumulation in the livers of rats under protein deprivation. The low-protein diet rapidly increased the hepatic 4E-BP1 mRNA level within 1 day, followed by the induction of hepatic TG accumulation. The knockdown of hepatic 4E-BP1 attenuated the TG accumulation in rat liver induced by the low-protein diet. 4E-BP1 knockdown also increased the protein level of carnitine palmitoyltransferase 1A (CPT1A), a regulator of fatty acid oxidation, in the liver of rats fed a low-protein diet. These results indicate that a low-protein diet increases the amount of 4E-BP1, leading to TG accumulation in rat liver. We thus conclude that 4E-BP1 plays an important role in inducing hepatic steatosis under protein deprivation.

The content of methemoglobin and carboxygemoglobin in rats red blood cell under the toxic damage after alimentary protein deprivation

The study of the content of total hemoglobin and its pathological derivates methemoglobin and carboxyhemoglobin in rats’ red blood cell under the toxic damage and alimentary protein deprivation are presented. In order to simulate the low-protein diet of animals for 28 days were kept, an isoenergy diet containing 4.7% protein, 10% fats and 85.3% carbohydrates, which was calculated according to the American Institute of Nutrition recommendations. The simulation of acute toxic damage was performed by per os acetaminophen-administration to experimental animals at doses of 1250 mg/kg of animal body weight. It was found that in experimental animals the 2-fold decrease in erythrocytes counts compared with the values of the control group was observed under the toxic damage after alimentary protein deprivation. In this case, both protein deficiency and the administration of acetaminophen toxic doses have a clear effect on the studied indicator. At the same time, a decrease of erythrocyte counts is accompanied by a simultaneous decrease of total hemoglobin content in rat erythrocyte hemolysate. In animals consuming a low protein diet, this may be due to a deficiency of essential amino acids involved in the synthesis of globin’s polypeptide chains. The maximal increase of methemoglobin content (5-fold compared with control) in rats’ erythrocyte hemolysate was recorded under the administration of acetaminophen toxic doses after alimentary protein deprivation. In these experimental conditions this may be associated with a decrease of methemoglobin reductase activity, which causes methemoglobin accumulates in erythrocytes in the form of Heinz bodies. An increase of the carboxyhemoglobin level in rats’ erythrocyte hemolysate of all the experimental groups compared with the control under the conditions of toxin administration after protein deficiency, probably indicates impaired synthesis and/or degradation of heme-containing proteins.

The content of sialic acids in blood plasma of rats under the conditions of acetaminophen-induced hepatotoxicity after alimentary protein deprivation

The work is devoted to the study of the fractional distribution of sialic acids in the blood plasma of rats under the conditions of toxic damage with acetaminophen after alimentary protein deprivation. The content of free, protein-bound and oligo-bound sialic acids in the blood plasma of animals was investigated under experimental conditions. The animals consumed a semi-synthetic diet during the experiment according to the recommendations of the American Institute of Nutrition. In order to simulate alimentary protein deprivation, rats received a low-protein diet containing 1/3 of the standard daily protein requirement daily for 28 days. The animals were modeled acute toxic damage with acetaminophen after four weeks of experimental diet. The administration of the toxin was carried out at doses of 1250 mg/kg animal body weight in suspension in 2 % starch gel solution once a day for 2 days by gavage. The concentration of free, protein- and oligo-bound sialic acids was determined spectrophotometrically at 549 nm by color reaction with thiobarbituric acid. Removal of non-sialic acid specific chromogens were performed by the addition of n-butanol. It has been shown that the increase of total sialic acids in the blood plasma of protein-deficient rats (by 40% compared to control) is due only to the increase in the level of the oligo-bound fraction. Thus, protein deficiency is a key factor in the established changes, which probably indicates the intensification of catabolism processes of intracellular easily mobilized proteins under the conditions of protein deficiency in the diet. At the same time, toxin (acetaminophen) intake, leads to an increase in the concentration of total sialic acids, mainly due to the increase of free and protein-bound fractions, which indicates the development of inflammatory processes in the tissues of the body, regardless of the amount of exogenous protein consumed.

Influence of actual nutrition and energy consumption on the somatic protein deprivation syndrome formation among Tambov female students aged 18-22 years

Aim of the study: to explore the energy status influence features on the formation of anthropometric syndrome of somatic protein deprivation among female students. Materials and methods. 236 girls aged 18-22 years were examined. We study somatometric features of physical development, components of body weight, actual nutrition and energy consumption. We estimate 25 somatometric characteristics measured with application of the automated medical diagnostic complex “Healthy child” (Tulinovsky instrument-making plant, Russia). Syndrome of somatic protein deprivation diagnosis was made by arm muscle circumference index. We carry out the evaluation of actual nutrition and energy consumption by the frequency method with the subsequent application of the computer program “Analysis of human nutrition” (version 1.2.4) of the Scientific Research Institute of Nutrition. Results. With syndrome of somatic protein deprivation daily energy consumption was significantly reduced by 13 %. The main factor determining the level of daily energy consumption among female students is the actual body weight, as well as the amount of muscle mass, which were significantly less with syndrome of somatic protein deprivation than in the control. The level of basic metabolism with syndrome of somatic protein deprivation was also significantly reduced. At the same time, there were no significant differences in the caloric content of diets in these groups. They were in conformity with the age norms. Discussion. Energy costs, including physical activity, appears to be a regulated factor in the formation of somatic protein deprivation syndrome among female students, and its use should be controlled by somatometric signs of this syndrome.