Variability in brain ganglioside composition: A further molecular mechanism beside serum antifreeze-glykoproteins for adaptation to cold in Antarctic and Arctic-boreal fishes

Rahmann, H.; Schneppenheim, Reinhard; Hilbig, Reinhard; Lauke, G.

doi:10.1007/bf00258155

Cited by 14 publications

(1 citation statement)

References 30 publications

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“…This could be shown with an energy-filtering transmission electron microscope for Image Electron Energy-Loss Spectroscopy (Wohrmann unpubl.). Thus, normal conduction velocities of the neuronal membranes are maintained even below the freezing point (Rahmann et al 1984, Beckei-et al 1995. Furthermore, the high proportions of lactonization and 0-acetylation of the brain gangliosides in P. antarcticun~ represent an important modulation of the surface electrostatics of the neuronal membranes to ensure a regular functioning of action potentials.…”

Section: Life Historymentioning

confidence: 99%

Adaptations of the Antarctic silverfish Pleuragramma antarcticum (Pisces:Nototheniidae) to pelagic life in high-Antarctic waters

Wöhrmann¹,

Hagen²,

Kunzmann³

1997

Mar. Ecol. Prog. Ser.

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Most fishes in Antarctic waters belong to the suborder Notothc,nioidei, highly developed perciform fishes whlch have been able to occupy not only a variety of benthic but also pclagic niches in Antarctic waters. One of the rare truly pelagic fish species. Pleuragramma antarctlcurn, plays a pivotal role in high-Antarctic food webs, due to its exceptional abundance. To investigdte the life history of P.antarctic~lrn more than 16 000 specimens were collected in the W~d d e l l Sea during various cruises with RV 'Polarstern' Apart from the more general life cycle adaptations with respect to reproduction, migrations, and feeding behaviour. P. antarct~cum has developed a number of specific biochcmical and physiological adaptations to cope with the environmental conditions in these permanently cold and highly scasonal Antarctic waters. During its second summer P. anlarcticum starts to accumulate large lipid deposits, mainly in the form of triacylglycerols. These low-density compounds provide the species with hydrostatic lift, an important factor for a pelagic fish without a swlm bladder. The lipid stores may also serve as energy reserves. I lighly polar brain gangliosides suggest wide-ranging neurophysiological adaptations to ensure proper functioning of the nervous system in icy waters. To avoid freezing in the presence of frazil ice P. antarctlcum contains efficient antifreeze glycoproteins. A newly discovered glycoprotein acts as an additional antifreeze agent. Although pelagic, adult P antarcticum are rather sluggish, which is indicated by the small total gill area as well as blood physiological characteristics. Such behaviour diminishes routine energy costs. Blood viscosity is reduced and at least 2 major haemog l o b~n s are found Provided that these haemoglobins are functionally different, they indicate a strong relationship between physiological and biochemical adaptations of the oxygen transport system and life style P antar-cfcum represents a prime esdmple of the colnplexity of adaptations necessary to thrive in the pelagic realm of Antarctic shelf waters, a niche largely unoccup~cd by other fish species.

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Section: Life Historymentioning

confidence: 99%