Temperature Preference During Forelimb Regeneration in the Red‐Spotted Newt Notophthalmus Viridescens

Abstract

Red-spotted newts (Notophthalmus viridescens) are model organisms for regenerative research. These animals can regenerate limbs, tails, jaws, spinal cords, as well as the lens of the eye. Newts are small ectotherms that are aquatic as adults; as ectotherms, they naturally conform to the temperature of their surroundings. Environmental temperatures, however, can increase or decrease the red-spotted newt's metabolic processes, including their rate of tissue regeneration; whether an optimal temperature for this rate of regeneration exists is unknown. However, newts do exhibit behavioral preferences for certain temperatures, and these thermal preferences can change with season or with acclimation. Given this flexibility in behavioral thermoregulation, we hypothesized that the process of tissue regeneration could also affect thermal preference, given the metabolic costs or altered temperature sensitivities of tissue regrowth. It was predicted that regenerating newts would select an environmental temperature that maximized the rate of regeneration, however, this prediction was not fully supported. Thermal preference trials revealed that newts consistently selected temperatures between 24 and 25°C throughout regeneration. This temperature selection was warmer than that of uninjured conspecifics, but was lower than temperatures that would have further augmented the rate of regeneration. Interestingly, regenerating newts maintained a more stable temperature preference than sham newts, suggesting that accuracy in thermoregulation may be more important to regenerating individuals, than to noninjured individuals.

A staging system for the regeneration of a polyp from the aboral physa of the anthozoan Cnidarian Nematostella vectensis

“…Previous studies on Hydra (Peebles, ), planarians (Brøndsted and Brøndsted, ), fiddler crabs (Weis, ), and urodele amphibians (Schauble and Nentwig, ; Young et al, ; Tattersall et al, ) have also described a temperature‐based influence on the rate of regeneration. Similarly, the separation of regeneration into “wound healing” and “regenerating” phases was seen in newts (Schauble and Nentwig, ; Tattersall et al, ), salamanders (Bryant et al, ; Gardiner et al, ), and planarians (Brøndsted and Brøndsted, ); however, although the wound healing phase in newts also appeared to be temperature independent (Schauble and Nentwig, ; Tattersall et al, ), that of the planarians appeared to vary with temperature, although this is difficult to assess from the published data (Brøndsted and Brøndsted, ). Recent work in Nematostella has shown that, in bisection of juvenile polyps (5–10 mm in length), cell proliferation begins to increase roughly 24 hpa (at 22°C), reaching a maximum at roughly 48 hpa (Passamaneck and Martindale, ).…”

“…The two distinct phases of regeneration, the first being temperature independent (Stages 0-2) and the other being temperature dependent (Stages 2-5), suggest that the metabolic demands on wound closure are low, compared with the metabolically intensive morphological restructuring occurring at the later regeneration stages. Previous studies on Hydra (Peebles, 1898), planarians (Brïndsted and Brïndsted, 1961), fiddler crabs (Weis, 1976), and urodele amphibians (Schauble and Nentwig, 1974;Young et al, 1983;Tattersall et al, 2012) have also described a temperature-based influence on the rate of regeneration. Similarly, the separation of regeneration into "wound healing" and "regenerating" phases was seen in newts (Schauble and Nentwig, 1974;Tattersall et al, 2012), salamanders Gardiner et al, 2002), and planarians (Brïndsted and Brïndsted, 1961); however, although the wound healing phase in newts also appeared to be temperature independent (Schauble and Nentwig, 1974;Tattersall et al, 2012), that of the planarians appeared to vary with temperature, although this is difficult to assess from the published data (Brïndsted and Brïndsted, 1961).…”

Evolution, comparative biology and ontogeny of vertebrate heart regeneration

“…Newts exhibit certain preferences for temperatures, which can change with season or acclimation. The study by Tattersall et al 141 demonstrated that newts display a preference for warmer temperatures following amputation compared with newts prior to surgery and compared with uninjured conspecific controls. Moreover, in zebrafish, the timing to complete fin regeneration also depends on temperature.…”

Trematode Parasite Infection Affects Temperature Selection in Aquatic Host Snails

“…To test for aquatic animal thermal preference, two apparatuses (53 cm # 27 cm) were constructed with plexiglass walls and a thermally conductive surface covered with white contact paper (Tattersall et al 2012). Three plastic dividers created four individual lanes (53 cm # 6.75 cm) such that each animal could turn and move without constraint.…”

“…Three plastic dividers created four individual lanes (53 cm # 6.75 cm) such that each animal could turn and move without constraint. We added 1.1 L of fully aerated water (i.e., water aerated overnight with air stones) to keep water levels low and avoid a vertical stratification of temperatures (Lefcort and Eiger 1993;Tattersall et al 2012). In pilot trials, a vertical stratification of temperatures was unavoidable with a water level of 4 cm (to fully immerse large snails), and thus we filled each apparatus to a depth of ∼1.2 cm, which was adequate to avoid a vertical cline of temperatures but deep enough to allow the foot and a portion of the shell of the snail to be submerged.…”