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Alpha-ketoglutarate supplementation in long-lived Drosophila melanogaster: Impact on lifespan and metabolic responses.

Studies on antiaging remedies in insect models sometimes show discrepancies in results. These discrepancies could be explained by different responses of short- and long-lived strains on the antiaging remedies. The purpose of the study was to test whether life-prolonging effects of alpha-ketoglutarate (AKG), observed in nematodes and fruit flies, would be reproduced in long-lived Drosophila melanogaster flies. Lifespan was assayed in flies kept in demographic cages. Fecundity, proportion of flies capable of negative geotaxis, starvation resistance, time of heat coma onset, levels of triacyglycerols, body glucose, glycogen, activities of glutamate dehydrogenase, catalase, glutathione-S-transferase, hexokinase, phosphofructokinase, pyruvate kinase, lactate, and glutamate dehydrogenases were assessed. Dietary AKG did not affect fly lifespan on the diet with 5% yeast and 5% sucrose (5Y:5S) and on the diet with 9% yeast and 1% sucrose (9Y:1S), but increased lifespan on the low-protein diet (1Y:9S). Twenty-five-day-old female flies fed a 5Y:5S diet with 10 mM AKG for 3 weeks, did not differ from the control group (without AKG) in climbing activity, resistance to heat stress, and starvation. The levels of glucose and glycogen were unaffected but the levels of triacylglycerols were lower in AKG-fed female flies. No differences in activities of glycolytic enzymes, NADPH-producing enzymes, glutamate dehydrogenase, oxygen consumption, and levels of oxidative stress markers were observed between the control and AKG-fed flies. However, AKG-fed flies had lower activities of catalase and glutathione-S-transferase. These results suggest that potential antiaging remedies, such as AKG, may not extend lifespan in long-living organisms despite influencing several metabolic parameters.

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Copper-substituted magnetite as a Fenton-like catalyst boosted with electromagnetic heating

Copper-substituted magnetite samples Fe3-xCuxO4 (x = 0.0; 0.02; 0.05; 0.1) were synthesized using the co-precipitation method. XRD data revealed that the synthesized samples retain the cubic spinel structure of magnetite. The obtained materials were tested as heterogeneous Fenton catalysts to destroy organic pollutants and inactivate bacteria. The model organic pollutants were oxytetracycline, Congo Red dye, and Methylene Blue dye having neutral, anionic, and cationic nature, respectively. These organic pollutants differ in their adsorption on magnetite surface: oxytetracycline < Congo Red < Methylene Blue. The same order stays for their decomposition rates. The copper-substituted magnetite catalysts also ensure effective inactivation of E.coli bacteria. A contact time of 60 min is sufficient to reduce the number of bacteria by 6-log. In all tests, the catalytic activity of magnetite increases with the increase in Cu content. The maximum catalytic activity was recorded for the Fe2.9Cu0.1O4 sample. Since the copper-substituted magnetite samples are ferromagnetic, they absorb a high-frequency electromagnetic field. Electromagnetic heating results in a significant increase in catalytic activity: the rate constants of the studied catalytic reactions are increased by 1.5–5 times. Thus, copper-doped magnetite is a hetero-Fenton catalyst capable of increasing activity by electromagnetic heating. The adjustable catalytic activity may be useful in water disinfection, where bacterial load varies greatly.

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Water disinfection using hydrogen peroxide with fixed bed hematite catalyst - kinetic and activity studies.

A lab-scale reactor with a fixed-bed hematite catalyst for the effective decomposition of H2O2 and bacteria inactivation was designed. The bactericidal effect is the largest at a low initial bacterial count of 2·103CFU/L, which is typical for natural surface waters. When using a 5mM H2O2 solution and a residence time of 104min, the reduction in the number of E. coli bacteria is about 3.5-log. At a higher initial bacterial count of 1-2·104CFU/L, a 5mM H2O2 solution reduces the bacteria number by about 4-log. The H2O2 decomposition follows the log-linear kinetics of a first-order reaction while the bacterial inactivation does not. The kinetics of bacterial inactivation was described using the Weibull model in the modified form: log10(N0/N) =b · tn. The values of the non-linearity parameter n were found to be lower than 1, indicating that bacterial inactivation slows down over time. With increasing initial H2O2 concentration, the rate parameter b increases while the non-linearity parameter n decreases. With increasing temperature, both parameters increase. The stability of the catalyst has been proved by XRD, FTIR, SEM, and ICP-OES. The concentration of iron leaching into water during disinfection is much lower than the limit declared by WHO for iron in drinking water. The results show that technical-grade hematite is a promising Fenton-like catalyst for water disinfection. The fixed-bed reactor can be the basis of the mobile installations for water purification in emergencies.

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Life-History Trade-Offs in Drosophila: Flies Select a Diet to Maximize Reproduction at the Expense of Lifespan.

Macronutrient intake impacts physiology, behavior, and gene expression in a wide range of organisms. We used the response surface methodology to compare how life history traits, lifespan, and reproduction differ as a function of protein and carbohydrate intakes under choice and no-choice feeding regimens in the fruit fly, Drosophila melanogaster. We found that when offered a choice of nutritionally complementary foods mated female flies regulated toward a protein to carbohydrate ratio (P:C) that was associated with shortened lifespan and maximal egg production when compared to response surfaces derived from flies fed 1 of a range of fixed diets differing in P:C (no-choice regimen). This difference in lifespan between choice and no-choice feeding was not seen in males or virgin flies, reflecting the fact that increased protein intake is triggered by mating to support egg production. However, whereas in mated females a higher P:C intake was associated with greater egg production under both choice and no-choice feeding, contrary to expectations, choice-fed mated flies laid fewer eggs than no-choice flies on equivalent macronutrient intakes, perhaps reflecting that they had to ingest twice the volume of food to attain an equivalent intake of nutrients than no-choice flies on a diet of equivalent P:C ratio.

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Premature Centromere Division (PCD) as a Cause of Genome Instability in Children with Acute Lymphoblastic Leukemia

Premature centromere division (PCD) and C-anaphase are well known phenomena in leukemias. However, their biological significance is not well understood. We describe the relationship of levels of PCD and C-anaphase with leukemic phase, blasts, aneuploidy and polyploidy in children with acute lymphoblastic leukemia (ALL). Methods Cytogenetic preparations of bone marrow (BM) and peripheral blood (PB) cells from 57 children with ALL and 15 healthy children were evaluated. For children with ALL, cells were examined prior to treatment in the acute phase and during remission. PCD and C-anaphase designations were assigned to chromosomal preparations and analyzed. Results The PCD and C-anaphase levels in BM and PB cells were significantly higher in the acute phase of ALL and decreased, approaching normal during remission. Strong correlations were found between PCD levels in PB (r = 0.890) and BM (r = 0.896) cells compared with blast levels in PB cells. Strong correlations were observed between PB levels of aneuploid (r = 0.832) and polyploid (r = 0.955) cells compared with PCD levels in PB cells. The C-anaphase levels in PB (r = 0.139) and BM (r = 0.171) compared with blasts in PB did not demonstrate a positive correlation. Conclusions Our data demonstrates that PCD is a cause of genome instability associated with ALL and that the phenomenon of PCD and C-anaphase provide additional criteria for diagnosis of ALL and its remission.

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Teaching students in high school using multimedia technologies

The peculiarities of the training of specialists in higher education using multimedia technologies are clarified and their importance and necessity for modern education are shown. Based on the recorded didactic and technical pedagogical capabilities of multimedia, we will identify potential functions that can be differentially implemented in the educational space. Manipulation, deformation, contamination, toning of images, discrete presentation of audiovisual information is considered; fixation of a selected part of visual information for movement, its further examination "under a magnifying glass", demonstration of processes and events in the real-time, multi-window presentation of audiovisual information, which intensify the educational process and strengthen the motivational effect in the educational field. Research and experimental work were carried out, which made it possible to find out the peculiarities of the training of specialists in higher education using multimedia technologies and to prove their importance and necessity for modern education. We have reasonably identified the stages that are important for the educational space for the qualitative application of knowledge and skills in the training of specialists; advantages of the introduction of multimedia technologies; various aspects of the use of computer software multimedia tools in the process of professional training of a specialist are named.

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Open Access