Regulation of supercooling and nucleation in a freeze intolerant beetle (Tenebrio molitor)

Johnston, Sean L.; Lee, Richard

doi:10.1016/0011-2240(90)90043-4

Cited by 31 publications

(15 citation statements)

References 22 publications

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“…Several studies have reported that the capacity to supercool decreases with increasing body mass (Johnston and Lee, 1990;Lee and Costanzo, 1998). Although our data partly support these results, with the smallest eutardigrade in our study (M. sapiens) having the lowest (though not significantly so) SCP of all tested eutardigrades, it may be challenged by the presence of the much higher SCP of the equally small heterotardigrades E. granulatus and E. testudo.…”

Section: Discussionsupporting

confidence: 54%

Freeze tolerance, supercooling points and ice formation: comparative studies on the subzero temperature survival of limno-terrestrial tardigrades

Hengherr

Worland

Reuner

et al. 2009

Journal of Experimental Biology

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SUMMARYMany limno-terrestrial tardigrades live in unstable habitats where they experience extreme environmental conditions such as drought, heat and subzero temperatures. Although their stress tolerance is often related only to the anhydrobiotic state, tardigrades can also be exposed to great daily temperature fluctuations without dehydration. Survival of subzero temperatures in an active state requires either the ability to tolerate the freezing of body water or mechanisms to decrease the freezing point. Considering freeze tolerance in tardigrades as a general feature, we studied the survival rate of nine tardigrade species originating from polar, temperate and tropical regions by cooling them at rates of 9, 7, 5, 3 and 1°C h -1 down to -30°C then returning them to room temperature at 10°C h -1 . The resulting moderate survival after fast and slow cooling rates and low survival after intermediate cooling rates may indicate the influence of a physical effect during fast cooling and the possibility that they are able to synthesize cryoprotectants during slow cooling. Differential scanning calorimetry of starved, fed and cold acclimatized individuals showed no intraspecific significant differences in supercooling points and ice formation. Although this might suggest that metabolic and biochemical preparation are non-essential prior to subzero temperature exposure, the increased survival rate with slower cooling rates gives evidence that tardigrades still use some kind of mechanism to protect their cellular structure from freezing injury without influencing the freezing temperature. These results expand our current understanding of freeze tolerance in tardigrades and will lead to a better understanding of their ability to survive subzero temperature conditions.

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Section: Discussionsupporting

confidence: 54%

Freeze tolerance, supercooling points and ice formation: comparative studies on the subzero temperature survival of limno-terrestrial tardigrades

Hengherr

Worland

Reuner

et al. 2009

Journal of Experimental Biology

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“…If all larvae are likely to require THPs eventually, constitutive THP expression is not necessarily wasteful, particularly if the proteins are degraded very slowly. As well, Johnston & Lee [22] found that the supercooling ability of T. molitor larvae was inversely proportional to their mass. Therefore, larger larvae may constitutively express moderate levels of THPs to provide at least a few degrees of protection in the case of a sudden temperature decrease.…”

Section: Discussionmentioning

confidence: 98%

Developmental and environmental regulation of antifreeze proteins in the mealworm beetle Tenebrio molitor

Graham¹,

Walker

Davies

2000

European Journal of Biochemistry

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The yellow mealworm beetle, Tenebrio molitor, contains a family of small Cys-rich and Thr-rich thermal hysteresis proteins that depress the hemolymph freezing point below the melting point by as much as 5.5 8C (DT thermal hysteresis). Thermal hysteresis protein expression was evaluated throughout development and after exposure to altered environmental conditions. Under favorable growth conditions, small larvae (11±13 mg) had only low levels of thermal hysteresis proteins or thermal hysteresis protein message, but these levels increased 10-fold and 18-fold, respectively, by the final larval instar (. 190 mg), resulting in thermal hysteresis . 3 8C. Exposure of small larvae (11±13 mg) to 4 weeks of cold (4 8C) caused an < 20-fold increase in thermal hysteresis protein concentration, well in excess of the less than threefold developmental increase seen after 4 weeks at 22 8C. Exposure of large larvae (100±120 mg) to cold caused 12-fold and sixfold increases in thermal hysteresis protein message and protein levels, respectively, approximately double the maximum levels they would have attained in the final larval instar at 22 8C. Thus, thermal hysteresis increased to similar levels (. 4 8C) in the cold, irrespective of the size of the larvae (the overwintering stage). At pupation, thermal hysteresis protein message levels decreased . 20-fold and remained low thereafter, but thermal hysteresis activity decreased much more slowly. Exposure to cold did not reverse this decline. Desiccation or starvation of larvae had comparable effects to cold exposure, but surprisingly, short daylength photoperiod or total darkness had no effect on either thermal hysteresis or message levels. As all environmental conditions that caused increased thermal hysteresis also inhibited growth, we postulate that developmental arrest is a primary factor in the regulation of T. molitor thermal hysteresis proteins.

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“…Probably the most frequently documented variation in low‐temperature thermotolerance of insects associated with ontogeny is that attributed to variation among life stages (e.g. Tucić, 1979; Chen, Denlinger & Lee, 1987; Punzo & Huff, 1988; Bale, 1991; Johnston & Lee, 1990; Czajka & Lee, 1990; Brokerhof, Morton & Banks, 1993; Watson & Hoffmann, 1995; Gilchrist et al , 1997; Vernon & Vannier, 1996; Klok & Chown, 2001; Carrillo et al , 2005; Jensen et al , 2007; Terblanche et al , 2007 b ). For example, Paractora dreuxi larvae had lower CTmin than adults (‐5.1°C vs. ‐2.7°C) (Klok & Chown, 2001), while supercooling points (SCP or crystallization temperature) varied among ‐22.6, ‐13.0, ‐16.2, ‐16.9, ‐18.9 and ‐18.7°C in eggs, second instar larvae, final‐instar larvae, pupae, adult females and adult males, respectively, of the tineid moth Tineola bisselliella (Chauvin & Vannier, 1997).…”

Section: Empirical Examplesmentioning

confidence: 99%

Insect thermal tolerance: what is the role of ontogeny, ageing and senescence?

2008

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Temperature has dramatic evolutionary fitness consequences and is therefore a major factor determining the geographic distribution and abundance of ectotherms. However, the role that age might have on insect thermal tolerance is often overlooked in studies of behaviour, ecology, physiology and evolutionary biology. Here, we review the evidence for ontogenetic and ageing effects on traits of high-and low-temperature tolerance in insects and show that these effects are typically pronounced for most taxa in which data are available. We therefore argue that basal thermal tolerance and acclimation responses (i.e. phenotypic plasticity) are strongly influenced by age and/or ontogeny and may confound studies of temperature responses if unaccounted for. We outline three alternative hypotheses which can be distinguished to propose why development affects thermal tolerance in insects. At present no studies have been undertaken to directly address these options. The implications of these age-related changes in thermal biology are discussed and, most significantly, suggest that the temperature tolerance of insects should be defined within the age-demographics of a particular population or species. Although we conclude that age is a source of variation that should be carefully controlled for in thermal biology, we also suggest that it can be used as a valuable tool for testing evolutionary theories of ageing and the cellular and genetic basis of thermal tolerance.

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Regulation of supercooling and nucleation in a freeze intolerant beetle (Tenebrio molitor)

Cited by 31 publications

References 22 publications

Freeze tolerance, supercooling points and ice formation: comparative studies on the subzero temperature survival of limno-terrestrial tardigrades

Freeze tolerance, supercooling points and ice formation: comparative studies on the subzero temperature survival of limno-terrestrial tardigrades

Developmental and environmental regulation of antifreeze proteins in the mealworm beetle Tenebrio molitor

Insect thermal tolerance: what is the role of ontogeny, ageing and senescence?

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