title: Dietary alpha-ketoglutarate increases cold tolerance in Drosophila melanogaster and enhances protein pool and antioxidant defense in sex-specific manner.
abstract: Alpha-ketoglutarate (AKG) is an important intermediate in Krebs cycle which bridges the metabolism of amino acids and carbohydrates. Its effects as a dietary supplement on cold tolerance were studied in Drosophila melanogaster Canton S. Two-day-old adult flies fed at larval and adult stages with AKG at moderate concentrations (5-10mM) recovered faster from chill coma (0°C for 15min or 3h) than control ones. The beneficial effect of AKG on chill coma recovery was not found at its higher concentrations, which suggests hormetic like action of this keto acid. Time of 50% observed mortality after 2h recovery from continuous cold exposure (-1°C for 3-31h) (LTi50) was higher for flies reared on 10mM AKG compared with control ones, showing that the diet with AKG enhanced insect cold tolerance. In parallel with enhancement of cold tolerance, dietary AKG improved fly locomotor activity. Metabolic effects of AKG differed partly in males and females. In males fed on AKG, there were no differences in total protein and free amino acid levels, but the total antioxidant capacity, catalase activity and low molecular mass thiol content were higher than in control animals. In females, dietary AKG promoted higher total antioxidant capacity and higher levels of proteins, total amino acids, proline and low molecular mass thiols. The levels of lipid peroxides were lower in both fly sexes reared on AKG as compared with control ones. We conclude that both enhancement of antioxidant system capacity and synthesis of amino acids can be important for AKG-promoted cold tolerance in D. melanogaster. The involvement of AKG in metabolic pathways of Drosophila males and females is discussed.
authors: Department of Biochemistry and Biotechnology, Vasyl Stefanyk Precarpathian National University, 57 Shevchenko Str., Ivano-Frankivsk 76018, Ukraine. Electronic address: bayliak@ukr.net.
authors: Maria M
authors: MM
authors: Bayliak
authors: Department of Biochemistry and Biotechnology, Vasyl Stefanyk Precarpathian National University, 57 Shevchenko Str., Ivano-Frankivsk 76018, Ukraine.
authors: Maria P
authors: MP
authors: Lylyk
authors: Department of Biochemistry and Biotechnology, Vasyl Stefanyk Precarpathian National University, 57 Shevchenko Str., Ivano-Frankivsk 76018, Ukraine.
authors: Halyna V
authors: HV
authors: Shmihel
authors: Department of Biochemistry and Biotechnology, Vasyl Stefanyk Precarpathian National University, 57 Shevchenko Str., Ivano-Frankivsk 76018, Ukraine.
authors: Oksana M
authors: OM
authors: Sorochynska
authors: Department of Biochemistry and Biotechnology, Vasyl Stefanyk Precarpathian National University, 57 Shevchenko Str., Ivano-Frankivsk 76018, Ukraine.
authors: Oksana V
authors: OV
authors: Manyukh
authors: Department of Biology, Lund University, Sölvegatan 35, 223 62 Lund, Sweden; Department of Medical Biology, Institute of Rural Medicine, Jaczewskiego 2, 20-950 Lublin, Poland.
authors: Stefan G
authors: SG
authors: Pierzynowski
authors: Department of Biochemistry and Biotechnology, Vasyl Stefanyk Precarpathian National University, 57 Shevchenko Str., Ivano-Frankivsk 76018, Ukraine. Electronic address: lushchak@pu.if.ua.
authors: Volodymyr I
authors: VI
authors: Lushchak
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D003080:Cold Temperature; D058639:Cold-Shock Response; D019587:Dietary Supplements / Q000032:analysis; D029721:Drosophila Proteins / Q000378:metabolism; D004331:Drosophila melanogaster / Q000502:physiology*; D005260:Female; D006458:Hemolymph / Q000378:metabolism; D007656:Ketoglutaric Acids / Q000032:analysis / Q000378:metabolism*; D015227:Lipid Peroxidation; D008297:Male; D053858:Metabolic Networks and Pathways; D012727:Sex Characteristics
chemical_list: D000596:Amino Acids; D000975:Antioxidants; D029721:Drosophila Proteins; D007656:Ketoglutaric Acids; D002374:Catalase
keywords: Amino acids; Chill coma; Proline; Stress recovery; Thiols