Dietary protein defines stress resistance, oxidative damages and antioxidant defense system in Drosophila melanogaster

Dietary interventions have been previously shown to influence lifespan in diverse model organisms. Manipulations with macronutrients content including protein and amino acids have a significant impact on various fitness and behavioral traits in the fruit fly Drosophila melanogaster. Therefore, we asked if yeast amount of the diet could influence stress resistance and antioxidant defense system in Drosophila. We examined the effects of four diets differing in the relative level of yeast, as a source of protein, on resistance to cold, heat, starvation and oxidative stress induced by menadione as well as activities of antioxidant enzymes and levels of oxidative stress markers. Protein restriction as well protein-enriched diet led to a reduction of survival under starvation and oxidative stress conditions. However, enhanced resistance to heat shock was affected by high yeast concentration in the diet. Also, protein-rich diets resulted in higher activity of antioxidant enzymes. Increased levels of protein thiols, low-molecule mass thiols, lipid peroxides in response to high yeast concentration in the diet were detected in females only. Thus, we can assume that consumption of a high protein diet could induce oxidative stress in fruit fly

Protein content in the parental diet affects cold tolerance and antioxidant system state in the offspring Drosophila

Dietary nutrients are the key determinants of the lifespan and metabolic health. The content of specific dietary compounds in the parental diet can epigenetically affect the physiological state of the offspring. Here, we studied how variable dietary protein content in the diet of parental generation affects antioxidant capacity of Drosophila melanogaster adult offspring. The dry yeast concentration ranging from 0.25% to 15% in the parental diet was the only variable in the experiments, whereas subsequent generation was kept on a diet of the same composition. We found, that flies fed with yeast-restricted (0.25%) diet produced F1 male flies with a higher cold tolerance and higher activity of the second-line antioxidant enzymes whereas in F1 females no effect of parental diet composition on the cold tolerance, catalase, GST, G6PDH, IDH activity and low thiols content was detected. The results suggest that nutrient-dependent changes of genes expression in the flies of paternal generation differently affect the stress response of males and females of the first-generation offspring

Developmental diet defines metabolic traits in larvae and adult Drosophila

The influence of the developmental nutrition on adult metabolism and overall performance becomes a hot topic of modern evolutionary biology. We used fruit fly Drosophila melanogaster as a model and experimental nutrition media composed of different sucrose content (S) and dry yeast content (Y): 0S:2Y, 20S:2Y or 0S:5Y, 20S:5Y to show that the developmental nutrition conditions define metabolism in larvae and adults. The level of glucose, glycogen, triglycerids and total lipids in the larvae and flies body were measured with the diagnostic assay kits. We found that individuals developed on either low-yeast or high-sugar diet showed delayed developmental rate. When kept on the diets with high sucrose content the larvae and adult flies had lower weight and higher amount of lipids as energy reserves. Restriction of dry yeast content in the diet of larvae led to a decrease in glycogen storage and protein levels in larvae and adult flies. The results obtained indicate that the metabolic traits revealed in adult flies are the result of nutrition during development and may be associated with mechanisms of organisms adaptation to the developmental nutritional conditions

Longevity and stress resistance are affected by activation of TOR/Myc in progenitor cells of Drosophila gut

Diverse physiological pathways have been shown to regulate longevity, stress resistance, fecundity and feeding rates, and metabolism in Drosophila. Here we tesed physiological traits in flies with Rheb and Myc- Rheb overexpressed in gut progenitor cells, known as enteroblasts (EBs). We found that activation of TOR signaling by overexpression of Rheb in EBs decreases survival and stress resistance. Additionall, we showed that Myc co-expression in EBs reduces fly fecundity and feeding rate. Rheb overexpression enhanced the level of whole body glucose. Higher relative expression of the metabolic genes dilps, akh, tobi and pepck was, however, observed. The role of TOR/Myc in the regulation of genes involved in lipid metabolism and protein synthesis was established. We showed a significant role of TOR/Myc in EBs in the regulation of the JAK/STAT, EGFR and insulin signaling pathways in Drosophila gut. These results highlight the importance of the balance between all different types of cells and confirm previous studies demonstrating that promotion of homeostasis in the intestine of Drosophila may function as a mechanism for the extension of organismal lifespan. Overall, the results demonstrate a role of TOR signaling and its downstream target Myc in EB cells in the regulation of Drosophila physiological processes

Intermittent fasting causes metabolic stress and leucopenia in young mice

Overweight and obesity became the worldwide epidemic resulting from overeating especially when a so-called Western diet rich in carbohydrates and fats is used. It is widely accepted that limitation of food consumption could help to withstand such state of adult organism, but information about younger groups is contradictory. The present study was undertaken to characterize the effects of intermittent fasting, using an every other day (EOD) fasting/feeding protocol, on hematological parameters and biochemical blood plasma indices in young mice from one to two months old. It was shown that intermittently fasted mice were characterized by a reduced body weight, reduced total number of blood leucocytes, lower glucose and lactate levels and higher activity of alanine aminotransferase and aspartate aminotransferase in blood plasma as compared with the age-matched control mice. To gain the same mass EOD animals needed to eat more food than ad libitum fed animals. These differences may probably be explained by a need to expend certain resources to combat stress induced by intermittent fasting. Our data showed that EOD feeding at a young age may negatively influence young mammals

Anhydrobiosis-Associated Nuclear DNA Damage and Repair in the Sleeping Chironomid: Linkage with Radioresistance

Anhydrobiotic chironomid larvae can withstand prolonged complete desiccation as well as other external stresses including ionizing radiation. To understand the cross-tolerance mechanism, we have analyzed the structural changes in the nuclear DNA using transmission electron microscopy and DNA comet assays in relation to anhydrobiosis and radiation. We found that dehydration causes alterations in chromatin structure and a severe fragmentation of nuclear DNA in the cells of the larvae despite successful anhydrobiosis. Furthermore, while the larvae had restored physiological activity within an hour following rehydration, nuclear DNA restoration typically took 72 to 96 h. The DNA fragmentation level and the recovery of DNA integrity in the rehydrated larvae after anhydrobiosis were similar to those of hydrated larvae irradiated with 70 Gy of high-linear energy transfer (LET) ions (4He). In contrast, low-LET radiation (gamma-rays) of the same dose caused less initial damage to the larvae, and DNA was completely repaired within within 24 h. The expression of genes encoding the DNA repair enzymes occurred upon entering anhydrobiosis and exposure to high- and low-LET radiations, indicative of DNA damage that includes double-strand breaks and their subsequent repair. The expression of antioxidant enzymes-coding genes was also elevated in the anhydrobiotic and the gamma-ray-irradiated larvae that probably functions to reduce the negative effect of reactive oxygen species upon exposure to these stresses. Indeed the mature antioxidant proteins accumulated in the dry larvae and the total activity of antioxidants increased by a 3–4 fold in association with anhydrobiosis. We conclude that one of the factors explaining the relationship between radioresistance and the ability to undergo anhydrobiosis in the sleeping chironomid could be an adaptation to desiccation-inflicted nuclear DNA damage. There were also similarities in the molecular response of the larvae to damage caused by desiccation and ionizing radiation

Effects of Glyphosate and its Formulation, Roundup, on Reproduction in Zebrafish (Danio rerio)

This is an open access article that is freely available in ORE or from the publisher's web site. Please cite the published version.Copyright © 2014 American Chemical SocietyRoundup and its active ingredient glyphosate are among the most widely used herbicides worldwide and may contaminate surface waters. Research suggests both Roundup and glyphosate induce oxidative stress in fish and may also cause reproductive toxicity in mammalian systems. We aimed to investigate the reproductive effects of Roundup and glyphosate in fish and the potential associated mechanisms of toxicity. To do this, we conducted a 21-day exposure of breeding zebrafish (Danio rerio) to 0.01, 0.5, and 10 mg/L (glyphosate acid equivalent) Roundup and 10 mg/L glyphosate. 10 mg/L glyphosate reduced egg production but not fertilization rate in breeding colonies. Both 10 mg/L Roundup and glyphosate increased early stage embryo mortalities and premature hatching. However, exposure during embryogenesis alone did not increase embryo mortality, suggesting that this effect was caused primarily by exposure during gametogenesis. Transcript profiling of the gonads revealed 10 mg/L Roundup and glyphosate induced changes in the expression of cyp19a1 and esr1 in the ovary and hsd3b2, cat, and sod1 in the testis. Our results demonstrate that these chemicals cause reproductive toxicity in zebrafish, although only at high concentrations unlikely to occur in the environment, and likely mechanisms of toxicity include disruption of the steroidogenic biosynthesis pathway and oxidative stress.Natural Environment Research Counci

Gene Discovery in the Threatened Elkhorn Coral: 454 Sequencing of the Acropora palmata Transcriptome

BACKGROUND: Cnidarians, including corals and anemones, offer unique insights into metazoan evolution because they harbor genetic similarities with vertebrates beyond that found in model invertebrates and retain genes known only from non-metazoans. Cataloging genes expressed in Acropora palmata, a foundation-species of reefs in the Caribbean and western Atlantic, will advance our understanding of the genetic basis of ecologically important traits in corals and comes at a time when sequencing efforts in other cnidarians allow for multi-species comparisons. RESULTS: A cDNA library from a sample enriched for symbiont free larval tissue was sequenced on the 454 GS-FLX platform. Over 960,000 reads were obtained and assembled into 42,630 contigs. Annotation data was acquired for 57% of the assembled sequences. Analysis of the assembled sequences indicated that 83-100% of all A. palmata transcripts were tagged, and provided a rough estimate of the total number genes expressed in our samples (~18,000-20,000). The coral annotation data contained many of the same molecular components as in the Bilateria, particularly in pathways associated with oxidative stress and DNA damage repair, and provided evidence that homologs of p53, a key player in DNA repair pathways, has experienced selection along the branch separating Cnidaria and Bilateria. Transcriptome wide screens of paralog groups and transition/transversion ratios highlighted genes including: green fluorescent proteins, carbonic anhydrase, and oxidative stress proteins; and functional groups involved in protein and nucleic acid metabolism, and the formation of structural molecules. These results provide a starting point for study of adaptive evolution in corals. CONCLUSIONS: Currently available transcriptome data now make comparative studies of the mechanisms underlying coral's evolutionary success possible. Here we identified candidate genes that enable corals to maintain genomic integrity despite considerable exposure to genotoxic stress over long life spans, and showed conservation of important physiological pathways between corals and bilaterians

Understanding How Microplastics Affect Marine Biota on the Cellular Level Is Important for Assessing Ecosystem Function: A Review

Plastic has become indispensable for human life. When plastic debris is discarded into waterways, these items can interact with organisms. Of particular concern are microscopic plastic particles (microplastics) which are subject to ingestion by several taxa. This review summarizes the results of cutting-edge research about the interactions between a range of aquatic species and microplastics, including effects on biota physiology and secondary ingestion. Uptake pathways via digestive or ventilatory systems are discussed, including (1) the physical penetration of microplastic particles into cellular structures, (2) leaching of chemical additives or adsorbed persistent organic pollutants (POPs), and (3) consequences of bacterial or viral microbiota contamination associated with microplastic ingestion. Following uptake, a number of individual-level effects have been observed, including reduction of feeding activities, reduced growth and reproduction through cellular modifications, and oxidative stress. Microplastic-associated effects on marine biota have become increasingly investigated with growing concerns regarding human health through trophic transfer. We argue that research on the cellular interactions with microplastics provide an understanding of their impact to the organisms’ fitness and, therefore, its ability to sustain their functional role in the ecosystem. The review summarizes information from 236 scientific publications. Of those, only 4.6% extrapolate their research of microplastic intake on individual species to the impact on ecosystem functioning. We emphasize the need for risk evaluation from organismal effects to an ecosystem level to effectively evaluate the effect of microplastic pollution on marine environments. Further studies are encouraged to investigate sublethal effects in the context of environmentally relevant microplastic pollution conditions