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Titolo:
Climate change and temperature-dependent biogeography: oxygen limitation of thermal tolerance in animals
Autore:
Portner, HO;
Indirizzi:
Alfred Wegener Inst Polar & Meeresforsch, D-27515 Bremerhaven, Germany Alfred Wegener Inst Polar & Meeresforsch Bremerhaven Germany D-27515 any
Titolo Testata:
NATURWISSENSCHAFTEN
fascicolo: 4, volume: 88, anno: 2001,
pagine: 137 - 146
SICI:
0028-1042(200104)88:4<137:CCATBO>2.0.ZU;2-K
Fonte:
ISI
Lingua:
ENG
Soggetto:
STANDARD METABOLIC-RATE; MITOCHONDRIAL-FUNCTION; ARENICOLA-MARINA; ANTARCTIC BIVALVE; ENERGY-METABOLISM; INNER MEMBRANE; MAJA-SQUINADO; ADAPTATION; LACTATE; TROUT;
Tipo documento:
Review
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Physical, Chemical & Earth Sciences
Citazioni:
78
Recensione:
Indirizzi per estratti:
Indirizzo: Portner, HO Alfred Wegener Inst Polar & Meeresforsch, D-27515 Bremerhaven,Germany Alfred Wegener Inst Polar & Meeresforsch Bremerhaven Germany D-27515
Citazione:
H.O. Portner, "Climate change and temperature-dependent biogeography: oxygen limitation of thermal tolerance in animals", NATURWISSEN, 88(4), 2001, pp. 137-146

Abstract

Recent years have shown a rise in mean global temperatures and a shift in the geographical distribution of ectothermic animals. For a cause and effect analysis the present paper discusses those physiological processes limiting thermal tolerance. The lower heat tolerance in metazoa compared with unicellular eukaryotes and bacteria suggests that a complex systemic rather than molecular process is limiting in metazoa. Whole-animal aerobic scope appears as tho first process limited at low and high temperatures, linked to the progressively insufficient capacity of circulation and ventilation. Oxygen levels in body fluids may decrease, reflecting excessive oxygen demand at high temperatures or insufficient aerobic capacity of mitochondria at lowtemperatures. Aerobic scope falls at temperatures beyond the thermal optimum and vanishes at low or high critical temperatures when transition to an anaerobic mitochondrial metabolism occurs. The adjustment of mitochondrial densities on top of parallel molecular or membrane adjustments appears crucial for maintaining aerobic scope and for shining thermal tolerance. In conclusion, the capacity of oxygen delivery matches full aerobic scope only within the thermal optimum. At temperatures outside this range, only time-limited survival is supported by residual aerobic scope, then anaerobic metabolism and finally molecular protection by heat shock proteins and antioxidative defence. In a cause and effect hierarchy, the progressive increase in oxygen limitation at extreme temperatures may even enhance oxidative and denaturation stress. As a corollary, capacity limitations at a complex level of organisation, the oxygen delivery system, define thermal tolerance Limitsbefore molecular functions become disturbed.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 09/07/20 alle ore 14:23:41