Metabolomic analysis of heat-hardening in adult green-lipped mussel (Perna canaliculus): A key role for succinic acid and the GABAergic synapse pathway

Synchronization of seasonal acclimatization and short‐term heat hardening improves physiological resilience in a changing climate

“…The stronger heat hardening response induced by an initial heat stress closer to the seasonal maximum temperature also suggests that the short hardening effect may depend on the predictability of temperature variation, which can be obtained from long‐term seasonal acclimatization. It has been reported that mounting a heat hardening response involves upregulation of multiple HSPs and regulation of energy metabolism after initial heat stresses (Dunphy et al., 2018; Gu et al., 2018). A heat hardening response that is beyond the actual demand or inappropriate will result in a loss of fitness due to the extra cost of energy, impaired locomotor activity or reduced fecundity (Gilbert & Miles, 2019; Huang et al., 2007; Jordan & Snell, 2002).…”

A single heat-stress bout induces rapid and prolonged heat acclimation in the California mussel,Mytilus californianus

“…Here, heat-stress bouts are typically separated by at least 24 h due to a semi-diurnal tidal cycle. Thus, in the context of a semidiurnal tidal cycle, the findings of Dunphy et al [9] may not be ecologically relevant. Twelve hours after an extreme heat-stress bout (which likely would occur midday), the temperatures would probably be much cooler as it would be nighttime.…”

“…After the extreme heat-stress bout, all mussels were placed back into the flow-through aquaria, and mussel survival was monitored every 2-3 days for four weeks [32]. Mussels that exhibited continuous gaping and were unresponsive to several strong squeezes of the valves were considered dead [9].…”

“…Phenotypic changes, like acclimatization, that increase thermal tolerance may be critical in enabling organisms to survive under these changing temperature conditions [2][3][4][5]. These adaptive changes in phenotype would ideally occur rapidly during an initial period of heat stress and persist long enough to allow the organism to withstand subsequent episodes of extreme heating [6][7][8][9][10][11]. Improvements in heat tolerance have generally been classified as either (i) rapid heat hardening from a single heat-stress bout, which confers transient heat tolerance that typically lasts less than 32 h [12,13] or (ii) slower heat acclimatization accomplished through repeated heat-stress bouts, which confers heat tolerance that can last for weeks to months [14][15][16].…”

“…Mussels have received substantial investigation in terms of their physiological responses to environmental change, notably temperature. Most studies of mussels' responses to heat stress have involved either a short heat-hardening bout in which mussels' thermal tolerance was transiently improved for 12 h [9], or longer duration heat acclimation studies which constantly submerge mussels for periods of several days to a few weeks which leads to various physiological changes (e.g. cardiac performance; [14,19]) and biochemical status (e.g.…”