Seasonal variation of newt forelimb regeneration under controlled environmental conditions

Abstract

Forelimb regeneration studies using the newt, Notophthalmus uiridescens, were done under constant environmental conditions at 20' C. A series of three-month regenerative studies were done during a two and onehalf year period. Under conditions which eliminated factors known to affect regeneration, such as temperature and variation in light-dark cycle, a significant seasonal variation in the regenerative process was found. The rate and amount of regenerative new growth during the summer was enhanced over that in winter. A series of repetitive regenerations in the same group of animals demonstrated that this variation was cyclic under controlled environmental conditions for long periods of time. It is suggested that a cyclic biologic rhythm, probably endocrine in nature, is responsible for the phenomenon.

Envirnmental conditions prerequisite for complete limb regeneration in the postmetamorphic adult land‐phase salamander, Ambystoma

“…These results suggest that the capacity to regenerate and the rate in which it regenerates may also be linked to a biological clock within the animal that can adjust its internal functions according to prevailing environmental conditions. This parallels the postulates by Schauble (1972), on seasonal interaction; Schauble and Nentwig (19741, on temperature interaction; and Maier and Singer (19771, on light interaction, affecting regeneration and regeneration rates in newts. Their studies showed that the conditions of temperature and amount of light either greatly affected the capacity of the newt to regenerate, or the rate at which it regenerated.…”

“…Indeed, it has been shown that adult landphase forms will survive for only 2 to 3 months under conditions usually employed for studies on regeneration in aquatic forms (Scadding, 1977). Since studies pertaining to regeneration rates in newts have shown that the rates are greatly affected by adverse environmental conditions (Schauble, 1972;Schauble and Nentwig, 1974;Maier and Singer, 19771, it seems plausible that the reported inability of the adult land-phase salamander to regenerate a limb may be due to adverse laboratory conditions rather than actual loss of the intrinsic capacity to regenerate. The present study was initiated to determine what environmental conditions were necessary for long-term survival of adult land-phase Ambystoma salamanders in the laboratory and whether regeneration would occur in animals maintained under those conditions for prolonged periods.…”

Forelimb regeneration from different levels of amputation in the newt,Notophthalmus viridescens: Length, rate, and stages

“…A number of other factors, including temperature (Ellis, 1909;Maderson and Licht, 1968;Schmidt, 1968), light cycle (Maderson and Salthe, 1971), and season of the year (Schauble, 1972), have been shown to influence both the extent and the rate of regeneration in vertebrate appendages. It is unclear whether body size (length or weight) or ageing in adult urodeles has any influence on the rate of limb regeneration.…”

Population characteristics, age structure, and growth dynamics of neritic juvenile green turtles in the northeastern Gulf of Mexico

“…Deposition of skeletal growth marks appears to be driven primarily by endogenous, physiological cycles (Schauble 1972, Simmons 1992) synchronized with variations in environmental factors (Castanet et al 1993). Annual deposition of skeletal growth marks has been demonstrated for known-age Kemp's ridley Lepidochelys kempii and loggerhead Caretta caretta turtles (Snover & Hohn 2004), as well as for bonemarked (Snover et al 2011), tagged, and known-age green turtles (Goshe et al 2010).…”