Camp. Bi~>chem. I’hyskd. Vt~i. 118A. No. 4. pp. 977-980. 1997 Ctjpyright 0 1YY7 Elsev~er Science Inc. All rights reserved. MN 0 100.C)6?9/97/$1 7.00 rll S03@0-Y629(97)0c70c74-? ELSEVIER zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHG Coenzyme Q Homologs and Trace Elements Content of Antarctic Fishes Chionodraco hamatus and Pugothenia bernucchii Compared With the Mediterranean Fish Mugil ceghalus B . Giardina~ M. L. Gozzo,JF B. Zappcosta,” L. Colacicco ,* C. CalliLT A. Mordente, f and zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONML S . zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLK Lippa” zyxwvutsrqponmlkjihgfedcbaZYXWVUTSR *INSTITUTE OF CHEMISTRY AND CLINICAL CHEMISTRY, ANL) ~INSTITUTE OF BIOLWIC.AL CHNISTW, FACULTY OF MEDICINE, CATHOLIC UNIVERSITY OF ROME, ITAL.) zyxwvutsrqponmlkjihgfedcbaZYXWV ABSTRACT. &enzyme Q and trace element contents of two antarctic tishrs (Pagotheniu bernucchii and Chiono- &a~-o humatus) were investigated and compared with that ci one temperate marine fish (Mugil cephulus). In p,lrticular. muscle and erythrncyte concentrations of coenzyme Q, vitamin E, selenium, cc~pper and zinc were determined. Antarctic fishes showed, at the level of their muscles, higher levels of selenium, zinc and copper c,mpared with M. ce@~&s. In antarctic fishes, in the place ot Q ic, the coenzyme Q form generally Ohserved in temperate fishes, only the homolog coenzyme QLI wah found. This particular finding h,lb heen related to the d&rrnce in the crystallization temperature existing between (:oQIo and G)Q,,. Moreover, the high Icvcls of zinc and selenium, ohserved in C. hamatus, correlate very well with a recent report on the prc.rcnce, in the liver of thib fish, of a rinc-hinding protein that, in additic)n, IS characterized hy an amino acid sequence closely aunila1 to that of a srlrni~lm-c~)ntaining protein isolated from ovine heart. All together, the results indicate, tar the antarctic species, iI high level of antioxidant defenses with respect tL) the meditrrranean hhh and may hc conyid- ered as a stimulating basis for further studies on the oxidative metahollbm of Antarctic organisms. (X)CII’ HIO(‘HEAI PHYSIOL 118A;4:977-980, 1997. 0 1997 Elsevier Science Inc. KEY WORDS. (&dative metaholism, cnensyme Q, vitamin E, \elcnium. zmc, copper. (:hir~nr&tcr~ hLltnccnc.\, Pqothmic~ brnlacchii, Mqil cephalus, reactive oxygen specie\ INTRODUCTION The phybico-chemical characteristics of Antarctica make this environment ideal for studying temperature adaptations at the various levels of organization of a given organism. Thus, the extrrme conditions of this habitat brought ahout some evolutionary adaptations, hoth at physiological and biochemical levels that, very often, resulted in peculiar properties of antarctic organisms. As to the fish fauna, the temperature td the oxygen-rich coastal Antarctic ocean is constantly at - 1.87”C, the equilibrium temperature of sea water and ice. Hence, antarctic fishes have developed mechanisms of cold adaptation such as the synthesis of “an- tifreeze” (glyco)peptides, which lower the freezing tempera- ture of hlnod in a noncolligative way, and the modification of some htmatological characteristics (decreased number of erythrocytes and hemoglobin concentration) to compensate 1996. for the increase of blood viscosity at low temperatures (7). As this latter aspect is concerned, the total lack of crythm- cytes and hence of hemoglobin in the hl,)od of tishes of the family Channichthyidae could he c~msidered the extreme stage of such evolutionary strategy. On the whole, antarctic fishes are fmely adjusted to their environment and intolt‘r- ant of warmer temperatures so that an increase in tempera- ture of only a few degrees centigrade generally leads tc> lethal effects (7). A well-known characteristic of antarctic t&es that pointed our attention to the oxidative metah<llism is their preferential utilization of the lipid metabolic pathway (5,16). This aspect caused us to investigate the presence, in various tissues trom different antarctic tishes, of those trace elements that are known to he essential for the func- tion of antioxidant enzymes (2). Along the SWNA line, par- ticular attention has been given to the presence of cot’~l- :yme Q and vitamin E. In fact, it is well known that the oxidative metabolism of the cell may lead to the production of some’ reactive oxygen species that directly or indirectly may attack sensitive macromolecules that comprise ccl1 membranes and chr~matin.