1887

Abstract

and are microaerophilic protozoa which rely on fermentative metabolism for energy generation. These organisms have developed a number of antioxidant defence strategies to cope with elevated O tensions which are inimical to survival. In this study, the ability of pyruvate, a central component of their energy metabolism, to act as a physiological antioxidant was investigated. The intracellular pools of 2-oxo acids in were determined by HPLC. With the aid of a dichlorodihydrofluorescein diacetate-based assay, intracellular reactive oxygen species generation by and suspensions was monitored on-line. Addition of physiologically relevant concentrations of pyruvate to and cell suspensions was shown to attenuate the rate of HO- and menadione-induced generation of reactive oxygen species. In addition, pyruvate was also shown to decrease the generation of low-level chemiluminescence arising from the oxygenation of anaerobic suspensions of . In contrast, addition of pyruvate to suspensions of respiring was shown to increase the generation of reactive oxygen species. These data suggest that (i) in and , pyruvate exerts antioxidant activity at physiological levels, and (ii) it is the absence of a respiratory chain in the diplomonads which facilitates the observed antioxidant activity.

Loading

Article metrics loading...

/content/journal/micro/10.1099/00221287-147-12-3359
2001-12-01
2021-10-23
Loading full text...

Full text loading...

/deliver/fulltext/micro/147/12/1473359a.html?itemId=/content/journal/micro/10.1099/00221287-147-12-3359&mimeType=html&fmt=ahah

References

  1. Adam, R. D. (1991). The biology of Giardia spp. Microbiol Rev 55, 706-732. [Google Scholar]
  2. Biagini, G. A., Suller, M. T. E., Finlay, B. J. & Lloyd, D. (1997). Oxygen uptake and antioxidant responses of the free-living diplomonad Hexamita sp. J Eukaryot Microbiol 44, 447-453.[CrossRef] [Google Scholar]
  3. Biagini, G. A., McIntyre, P. S., Finlay, B. J. & Lloyd, D. (1998). Carbohydrate and aminoacid fermentation in the free-living primitive protozoon Hexamita sp. Appl Environ Microbiol 64, 203-207. [Google Scholar]
  4. Biagini, G. A., Kirk, K., Schofield, P. J. & Edwards, M. R. (2000). Role of K+ and amino acids in osmoregulation by the free-living microaerophilic protozoon Hexamita inflata. Microbiology 146, 427-433. [Google Scholar]
  5. Brand, K. A. & Hermfisse, U. (1997). Aerobic glycolysis by proliferating cells: a protective strategy against reactive oxygen species. FASEB J 11, 388-395. [Google Scholar]
  6. Brown, D. M., Upcroft, J. A. & Upcroft, P. (1993). Cysteine is the major low molecular weight thiol in Giardia duodenalis. Mol Biochem Parasitol 61, 155-158.[CrossRef] [Google Scholar]
  7. Brown, D. M., Upcroft, J. A. & Upcroft, P. (1995). Free-radical detoxification in Giardia duodenalis. Mol Biochem Parasitol 72, 47-56.[CrossRef] [Google Scholar]
  8. Brown, D. M., Upcroft, J. A. & Upcroft, P. (1996). A thioredoxin reductase-class of disulphide reductase in the protozoan parasite Giardia duodenalis. Mol Biochem Parasitol 83, 211-220.[CrossRef] [Google Scholar]
  9. Brown, D. M., Upcroft, J. A., Edwards, M. R. & Upcroft, P. (1998). Anaerobic bacterial metabolism in the ancient eukaryote Giardia duodenalis.Int J Parasitol 28, 149-164.[CrossRef] [Google Scholar]
  10. Brugerolle, G. (1974). Contribution a l’etude cytologique et phyletique des diplozaires (zoomastigophorea, diplozoa, Dangeard 1910). Protistologica 1, 83-90. [Google Scholar]
  11. Buchmann, K., Uldal, A. & Lyholt, H. C. K. (1995). Parasite infections in Danish trout farms. Acta Vet Scand 36, 283-298. [Google Scholar]
  12. Dando, P. R., Fenchel, T., Jensen, P., O’Hara, S. C. M., Niven, S. J. & Schuster, U. (1993). Ecology of gassy, organic-rich sediment in a shallow subtidal area on the kattegat coast of Denmark. Mar Ecol Prog Ser 100, 265-271.[CrossRef] [Google Scholar]
  13. Dimopoulos, M., Bagnara, A. S. & Edwards, M. R. (2000). Characterisation and sequence analysis of a carbamate kinase gene from the diplomonad Hexamita inflata. J Eukaryot Microbiol 47, 499-503.[CrossRef] [Google Scholar]
  14. Edwards, M. R., Payne, K. D., Wilson, J. R. & Schofield, P. J. (1994). Giardial aminotransferases. In Giardia from Molecules to Disease , pp. 189-191. Edited by R. C. A. Thompson, J. A. Reynoldson & A. J. Lymbery. Wallingford:CAB International.
  15. Fenchel, T., Bernard, C., Esteban, G., Finlay, B. J., Hansen, P. J. & Iversen, N. (1995). Microbial diversity and activity in a Danish fjord with anoxic deep water. Ophelia 43, 45-100.[CrossRef] [Google Scholar]
  16. Halliwell, B. & Gutteridge, J. M. C. (1999).Free Radicals in Biology and Medicine. Oxford: Oxford University Press.
  17. Hayashi, T., Tsuchiya, H., Todoriki, H. & Naruse, H. (1982). High-performance liquid chromatography determination of alpha-keto acids in human urine and plasma. Anal Biochem 122, 173-179.[CrossRef] [Google Scholar]
  18. Holleman, A. F. (1904).Lehrbuch der organischen Chemie. Leipzig: Veit.
  19. Knodler, L. A., Edwards, M. R. & Schofield, P. J. (1994). The intracellular amino acid pools of Giardia intestinalis, Trichomonas vaginalis and Crithidia luciliae. Exp Parasitol 79, 117-125.[CrossRef] [Google Scholar]
  20. Kulda, J. & Nohynková, E. (1978). Flagellates of the human intestine and of the intestines of other species. In Parasitic Protozoa , pp. 2-127. Edited by J. P. Kreier. New York:Academic Press.
  21. Liao, J. C., Hoffman, N. E., Barboriak, J. J. & Roth, D. A. (1977). High-performance liquid chromatography of pyruvic and alpha-ketoglutaric acids and its application to urine samples. Clin Chem 23, 802-805. [Google Scholar]
  22. Lloyd, D., Boveris, A., Reiter, R., Filipkowski, M. & Chance, B. (1979). Chemiluminescence of Acanthamoeba castellanii.Biochem J 184, 149-156. [Google Scholar]
  23. Lloyd, D., James, C. J. & Hastings, J. W. (1985). Oxygen affinities of the bioluminescence systems of various species of luminous bacteria. J Gen Microbiol 131, 2137-2140. [Google Scholar]
  24. Lloyd, D., Harris, J. C., Maroulis, S., Biagini, G. A., Wadley, R. B., Turner, M. P. & Edwards, M. R. (2000). The microaerophilic flagellate Giardia intestinalis: oxygen and its reaction products collapse membrane potential and cause cytotoxicity. Microbiology 146, 3109-3118. [Google Scholar]
  25. Mertens, E. (1990). Occurrence of pyrophosphate:fructose 6-phosphate 1-phosphotransferase in Giardia lamblia trophozoites. Mol Biochem Parasitol 40, 147-149.[CrossRef] [Google Scholar]
  26. Paget, T. A., Kelly, M. L., Jarroll, E. L., Lindmark, D. G. & Lloyd, D. (1993a). The effects of oxygen on fermentation in Giardia lamblia. Mol Biochem Parasitol 57, 65-72.[CrossRef] [Google Scholar]
  27. Paget, T. A., Manning, P. & Jarroll, E. L. (1993b). Oxygen uptake in cysts and trophozoites of Giardia lamblia. J Euk Microbiol 40, 246-250.[CrossRef] [Google Scholar]
  28. Phillips, N. F. B., Li, Z. & Lindmark, D. G. (1997). Isolation of a pyrophosphate-dependent phosphofructokinase from Hexamita inflata. Mol Biochem Parasitol 90, 377-380.[CrossRef] [Google Scholar]
  29. Schofield, P. J., Costello, M., Edwards, M. R. & O’Sullivan, W. J. (1990). The arginine dihydrolase pathway is present in Giardia intestinalis. Int J Parasitol 20, 697-699.[CrossRef] [Google Scholar]
  30. Thompson, R. C. A., Reynoldson, J. A. & Mendis, A. H. W. (1993).Giardia and giardiasis. Adv Parasitol 32, 71-160. [Google Scholar]
  31. Townson, S. M., Hanson, G. R., Upcroft, J. A. & Upcroft, P. (1996). Characterisation and purification of pyruvate:ferredoxin oxidoreductase from Giardia duodenalis. Mol Biochem Parasitol 79, 183-193.[CrossRef] [Google Scholar]
  32. Wilhelm, E. R., Battino, R. & Wilcock, R. J. (1977). Low pressure solubility of gases in liquid water. Chem Rev 77, 219-262.[CrossRef] [Google Scholar]
http://instance.metastore.ingenta.com/content/journal/micro/10.1099/00221287-147-12-3359
Loading
/content/journal/micro/10.1099/00221287-147-12-3359
Loading

Data & Media loading...

Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error