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Titolo:
Experimental studies of ice nucleation in an Antarctic springtail (Collembola, Isotomidae)
Autore:
Block, W; Worland, MR;
Indirizzi:
British Antarctic Survey, NERC, Cambridge CB3 0ET, England British Antarctic Survey Cambridge England CB3 0ET idge CB3 0ET, England
Titolo Testata:
CRYOBIOLOGY
fascicolo: 3, volume: 42, anno: 2001,
pagine: 170 - 181
SICI:
0011-2240(200105)42:3<170:ESOINI>2.0.ZU;2-P
Fonte:
ISI
Lingua:
ENG
Soggetto:
COLD-HARDINESS; CRYPTOPYGUS-ANTARCTICUS; SIGNY ISLAND; AGENTS; SURVIVAL; INSECTS; BEETLES; MITES;
Keywords:
ice nucleator activity; ice nucleation spectra; inactivation; acclimation; supercooling point; Cryptopygus antarcticus; Antarctic; springtail;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
29
Recensione:
Indirizzi per estratti:
Indirizzo: Block, W British Antarctic Survey, NERC, Madingley Rd,High Cross, Cambridge CB3 0ET, England British Antarctic Survey Madingley Rd,High Cross Cambridge England CB3 0ET
Citazione:
W. Block e M.R. Worland, "Experimental studies of ice nucleation in an Antarctic springtail (Collembola, Isotomidae)", CRYOBIOLOGY, 42(3), 2001, pp. 170-181

Abstract

Ice nucleation was studied in field-fresh and acclimated (4 degreesC without food for 11-20 days) samples of the springtail Cryptopygus antarcticus Willem (Collembola. Isotomidae) at Rothera Research Station. Adelaide Islandon the Antarctic Peninsula. Ice nucleator activity (INA) was measured by afreezing droplet technique in addition to supercooling point (SCP) profiles and polyol, sugar, and water contents. Field and acclimated samples showed bimodal SCP distributions with a distinct high group (HG, mean SCP -8 to - 10 degreesC) and low group (LG: mean SCP - 23 to - 25 degreesC), which were significantly different. Acclimation at 4 degreesC increased the proportion of individuals in the LG relative to that in the HG without significanteffects on the mean SCP of both groups. INA of the HG was significantly greater than that of the LG. and acclimation further reduced the INA of the LG. The number of active ice nucleator agents (INAs) calculated for the HG of field samples increased by 23-100 times over the temperature range - 5 to- 8 degreesC compared to only 7 times for the LG over the same range. These differences were accentuated in the acclimation experiments. Glucose and galactose were the main carbohydrates in both field and acclimated springtails, with the latter compound occurring in almost twice the concentration in the LG compared with that in the HG. Acclimation reduced the concentration of both compounds (glucose by 77% and galactose by 54%). whereas water content increased significantly. Digestion of food may have continued during acclimation at 4 degreesC, which could reduce the LG INA. Lowering of temperature over time is more likely to elicit a cold hardening response than constant temperature acclimation. INA numbers calculated at the nucleation temperatures for C. antarcticus samples were higher in the LG than in the HG. However, inactivation of INAs may be a key mechanism underlying cold hardening in this species, either by sequestration within the cellular matrix orby being only seasonally active. (C) 2001 Academic Press.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 05/04/20 alle ore 03:40:34