The rapid cold hardening response of Drosophila melanogaster: Complex regulation across different levels of biological organization

In studies of insect cold-hardiness, the supercooling point (SCP) is defined as the temperature at which spontaneous nucleation of body fluids occurs. Despite having an SCP of −20 degrees C, adults of Drosophila melanogaster did not survive exposure to −5 degrees C, which suggests that cold shock causes lethal injury that is not associated with freezing. If, however, flies were chilled at 5 degrees C, for as little as 30 min, approximately 50% of the flies survived exposure to −5 degrees C for 2h. This capacity to cold-harden rapidly was greatest in 3- and 5-day-old adults. The rapid cold-hardening response was also observed in larvae and pupae: no larvae survived 2 h of exposure to −5 degrees C, whereas 63% pupariated if chilled at 5 degrees C before subzero exposure. Similarly, although exposure of pupae to −8 degrees C was lethal, if pre-chilled at 5 degrees C 22% eclosed. This extremely rapid cold-hardening response may function to allow insects to enhance cold-tolerance in response to diurnal or unexpected seasonal decreases in environmental temperature.

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Rapid cold-hardening protects Drosophila melanogaster from cold-induced apoptosis

APOPTOSIS ◽

10.1007/s10495-006-0048-2 ◽

2007 ◽

Vol 12 (7) ◽

pp. 1183-1193 ◽

Cited By ~ 86

Author(s):

Shu-Xia Yi ◽

Clifford W. Moore ◽

Richard E. Lee

Keyword(s):

Drosophila Melanogaster ◽

Cold Hardening ◽

Rapid Cold Hardening ◽

Induced Apoptosis

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Speed of exposure to rapid cold hardening and genotype drive the level of acclimation response in Drosophila melanogaster

Journal of Thermal Biology ◽

10.1016/j.jtherbio.2018.06.011 ◽

2018 ◽

Vol 76 ◽

pp. 21-28 ◽

Cited By ~ 4

Author(s):

Alison R. Gerken ◽

Olivia C. Eller-Smith ◽

Theodore J. Morgan

Keyword(s):

Drosophila Melanogaster ◽

Cold Hardening ◽

Rapid Cold Hardening ◽

Acclimation Response

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Cold shock and rapid cold hardening in Drosophila melanogaster

Cryobiology ◽

10.1016/0011-2240(88)90404-x ◽

1988 ◽

Vol 25 (6) ◽

pp. 546 ◽

Cited By ~ 4

Author(s):

M.C. Czajka ◽

R.E. Lee

Keyword(s):

Drosophila Melanogaster ◽

Cold Shock ◽

Cold Hardening ◽

Rapid Cold Hardening

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Rapid cold-hardening of Drosophila melanogaster (Diptera: Drosophiladae) during ecologically based thermoperiodic cycles

Journal of Experimental Biology ◽

10.1242/jeb.204.9.1659 ◽

2001 ◽

Vol 204 (9) ◽

pp. 1659-1666 ◽

Cited By ~ 10

Author(s):

J.D. Kelty ◽

R.E. Lee

Keyword(s):

Drosophila Melanogaster ◽

Low Temperatures ◽

Cold Hardiness ◽

Stress Protein ◽

Cold Hardening ◽

Short Term ◽

Rapid Cold Hardening ◽

Cold Tolerant ◽

Acclimatory Response ◽

Cooling Phase

In contrast to most studies of rapid cold-hardening, in which abrupt transfers to low temperatures are used to induce an acclimatory response, the primary objectives of this study were to determine (i) whether rapid cold-hardening was induced during the cooling phase of an ecologically based thermoperiod, (ii) whether the protection afforded was lost during warming or contributed to increased cold-tolerance during subsequent cycles and (iii) whether the major thermally inducible stress protein (Hsp70) or carbohydrate cryoprotectants contributed to the protection afforded by rapid cold-hardening. During the cooling phase of a single ecologically based thermoperiod, the tolerance of Drosophila melanogaster to 1 h at −7 degrees C increased from 5 +/− 5% survival to 62.5 +/− 7.3% (means +/− S.E.M., N=40-60), while their critical thermal minima (CTmin) decreased by 1.9 degrees C. Cold hardiness increased with the number of thermoperiods to which flies were exposed; i.e. flies exposed to six thermoperiods were more cold-tolerant than those exposed to two. Endogenous levels of Hsp70 and carbohydrate cryoprotectants were unchanged in rapidly cold-hardened adults compared with controls held at a constant 23 degrees C. In nature, rapid cold-hardening probably affords subtle benefits during short-term cooling, such as allowing D. melanogaster to remain active at lower temperatures than they otherwise could.

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