Tatlı Su Balıklarındaki (Oreochromis niloticus, Cyprinus carpio, Oncorhynchus mykiss) Solungaç Na,K-ATPaz Enzimlerinin Karakterizasyonu

Bu çal›flmada farkl› ekolojik gereksinimleri olan üç farkl› tatl› su bal›¤›nda (O. niloticus, C. carpio, O. mykiss) solungaç Na,KATPaz enzimlerinin karakterizasyonu yap›lm›flt›r. Ayn› zamanda solungaçlarda Na+, K+ ve Cl- düzeyleri de belirlenmifltir. En yüksek Na,K-ATPaz aktivitesi 100 mM Na+, 20 mM K+, 3-4 mM Mg+2, 1 mM Ouabain deriflimlerinde gözlenmifltir. O. mykiss’da (1,07 µmol Pi/mg prot/h), O. niloticus (7,25 µmol Pi/mg prot/h) ve C. carpio (7,44 µmol Pi/mg prot/h) ile karfl›laflt›r›ld›¤›nda gözlenen en düflük maximal h›z (Vmax) de¤eri, solungaçlardaki yüksek iyon düzeyleri ile iliflkilendirilebilir. Buna karfl›l›k, O. niloticus ve C. carpio’da yar› Vmax de¤erine sahip substrat deriflimleri (Km) ise, benzer Vmax de¤erlerine karfl›l›k farkl›l›k göstermektedir. O. niloticus’da C. carpio’ya oranla gözlenen düflük Km de¤erinin, de¤iflen ortam koflullar›nda O. niloticus’un daha dirençli olmas›ndan kaynaklanabilece¤i bildirilmifltir.

Anahtar Kelimeler:

Fish, gill, ion, Na, K-ATPase

Characterization of Branchial Na,K-ATPase from Three Freshwater Fish Species (Oreochromis niloticus, Cyprinus carpio, and Oncorhynchus mykiss)

Branchial Na,K-ATPase activity was characterized in 3 freshwater fish species (Oncorhynchus mykiss, Oreochromis niloticus, and Cyprinus carpio) with different ecological needs. Na+, K+, and Cl- concentrations in the gills were also measured. The maximal Na,K-ATPase activity was observed at 100 mM Na+, 20-40 mM K+, 3-4 mM Mg2+, and 1 mM ouabain. The maximal velocity (Vmax) of Na,K-ATPase isolated from O. mykiss (1.07 µmol Pi/mg prot/h) was lower than that isolated from O. niloticus (7.25 µmol Pi/mg prot/h) and C. carpio (7.44 µmol Pi/mg prot/h). Nevertheless, Na+, K+, and Cl- levels in O. mykiss were higher than the others. The lowest Vmax value can be attributed to the highest ion concentrations in the gills of O. mykiss. However, substrate concentrations, which give half of Vmax (Km) of Na,K-ATPase in the gills of O. niloticus and C. carpio, were different although they exhibited similar Vmax values. The low Km value in the gills of O. niloticus compared to C. carpio may be related to high resistance to changing environmental factors.

Keywords:

Fish, gill, ion, Na, K-ATPase,

PDF

___

Atkinson, A., Gatenby, A.O. and Lowe, A.G. 1973. The determination of inorganic orthophosphate in biological systems. Biochim. Biophys. Acta. 320: 195-204.
Bansal, S.K., Murthy, R.C. and Chandra, S.V. 1985. The effects of some divalent metals on cardiac and branchial Ca2+-ATPase in a freshwater fish Saccobranchus fossilis. Ecotox. Environ. Safe. 9: 373-377.
Canli, M. and Stagg, R.M. 1996. Effects of in vivo exposure to cadmium, copper and zinc on the activities of gill ATPases in the Norway lobster Nephrops norvegicus. Arch. Environ. Con. Tox. 31: 494-501.
Diaz, M., Cozzi, S., Almansa, E., Casariego, M., Bolanos, A., Cejas, J. and Lorenzo, A. 1998. Characterization of intestinal Na+-K+- ATPase in the gilthead seabream (Sparus aurata L.). Evidence for a tissue-specific heterogeneity. Comp. Biochem. Phys. 121B: 65- 76.
Evans, D.H., Piermarini, P.M. and Choe, K.P. 2005. The multifunctional fish gill: dominant site of gas exchange, osmoregulation, acid-base regulation, and excretion of nitrogenous waste. Physiol. Rev. 85, 97-177.
Gall, G.A.E. and Crandell, P.A. 1992. The rainbow trout. Aquaculture. 100: 1-10.
Guynn, S., Dowd, F. and Petzel, D. 2002. Characterization of gill Na/K- ATPase activity and ouabain binding in Antarctic and New Zealand nototheniid fish. Comp. Biochem. Phys. 131A: 363-374.
Handeland, S.O., Berge, A., Bjornsson, B.T. and Stefansson, S.O. 2000. Seawater adaptation by out-of season Atlantic salmon (Salmo salar L.) smolts at different temperatures. Aquaculture. 181: 377-396.
Heath, A.G. 1987. Water Pollution and Fish Physiology. CRC Press, Florida, USA, 245 pp.
Imsland, A.K., Gunnarsson, S., Foss, A. and Stefansson, S.O. 2003. Gill Na+,K+-ATPase activity, plasma chloride and osmolality in juvenile turbot (Scophthalmus maximus) reared at different temperatures and salinities. Aquaculture. 218: 671-683.
Inman, C.B.E. and Lockwood, A.P.M. 1977. Some effects of methylmercury and lindane on sodium regulation in the amphipod Gammarus duebeni during changes in the salinity of its medium. Comp. Biochem. Phys. 58C: 67-75.
Jagoe, C.H., Shaw-Allen, P.L. and Brundage, S. 1996. Gill Na+,K+- ATPase activity in largemouth bass (Micropterus salmoides) from three reservoirs with different levels of mercury contamination. Aquat. Toxicol. 36: 161-176.
Kamal, A.H.M.M. and Mair, G.C. 2005. Salinity tolerance in superior genotypes of tilapia, Oreochromis niloticus, Oreochromis mossambicus and their hybrids. Aquaculture. 247: 189-201.
Larsson, A., Haux, C. and Sjöbeck, M.L. 1985. Fish physiology and metal pollution: Results and experiences from laboratory and field studies. Ecotox. Environ. Safe. 9: 250-281.
Lowry, O.H., Rosebrough, N.J., Fara, N.J. and Randall, R.J. 1951. Protein measurements with the folin phenol reagent. J. Biol. Chem. 193: 265-275.
Metz, JR., van den Burg, E.H., Wendelaar Bonga, S.E. and Flik, G. 2003. Regulation of branchial Na+/K+-ATPase in common carp Cyprinus carpio L. acclimated to different temperatures. J. Exp. Biol. 206: 2273-2280.
Maitland, P.S. and Campbell, R.N. 1992. Freshwater fishes of the British Isles. Harper Collins Publishers, London, 368 pp.
Packer, R.K. and Garvin, J.L. 1998. Seasonal differences in activity of perch (Perca flavescens) gill Na+/KATPase. Comp. Biochem. Phys. 120B: 777-783.
Popma T. and Masser, M. 1999. Tilapia: Life History and Biology. SRAC Publication No. 283.
Sardella, B.A., Cooper, J., Gonzalez, R.J. and Brauner, C.J. 2004. The effect of temperature on juvenile tilapia hybrids (Oreochromis mossambicus x O. urolepis hornorum) exposed to full-strength and hypersaline seawater. Comp. Biochem. Phys. 137A: 621- 629.
Sunny, F. and Oommen, O.V. 2001. Rapid action of glucorticoids on branchial ATPase activity in Oreochromis mossambicus: an in vivo and in vitro study. Comp. Biochem. Phys. 130B: 323-330.
Ueng, Y.F., Liu, C., Lai, C.F., Meng, L.M., Hung, Y.Y. and Ueng, T.H. 1996. Effects of cadmium and environmental pollution on metallothionein and cytochrome P450 in tilapia. B. Environ. Contam. Tox. 57: 125-131.
Veillette, P.A. and Young, G. 2004. Temporal changes in intestinal Na+, K+-ATPase activity and in vitro responsiveness to cortisol in juvenile Chinook salmon. Comp. Biochem. Phys. 138A: 297-303.
Watson, T.A. and Beamish, F.W. 1981. The effects of zinc on branchial adenosine triphosphatase enzymes in vitro from rainbow trout, Salmo gairdneri. Comp. Biochem. Phys. 68C: 167-173.
Webb, N.A., Shaw, J.R., Morgan, J., Hogstrand, C. and Wood, C.M. 2001. Acute and chronic physiological effects of silver exposure in three marine teleosts. Aquat. Toxicol. 54: 161-178.