𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Behavioral, molecular and integrative mechanisms of amphibian osmoregulation

✍ Scribed by Hillyard, Stanley D.


Publisher
John Wiley and Sons
Year
1999
Tongue
English
Weight
147 KB
Volume
283
Category
Article
ISSN
0022-104X

No coin nor oath required. For personal study only.

✦ Synopsis


Amphibian water balance has been studied at many levels of biological order. Terrestrial species must react to environmental cues that relate to water availability while some arboreal species have cutaneous skin secretions that can reduce evaporative water loss. The Indian tree frog, Polypedates maculatus, uses cutaneous secretions and wiping behavior to lower evaporation but also relies on moist microclimates to endure prolonged survival away from water. The related species, P. leucomystax, inhabits wetter forest habitats. Preliminary studies with this species are unable to demonstrate the expression of wiping behavior, indicating that arid habitats may be a powerful selective force for this behavior. Laboratory experiments on rehydrating toads in the genus Bufo indicate that animals are able to detect changes in barometric pressure and humidity that might result in the availability of water under field situations. Experiments with Bufonid species and with spadefoot toads, Scaphiopus couchi, show that the peptide hormone, angiotensin II, stimulates cutaneous drinking in a similar manner seen for oral drinking by other vertebrate classes. Amphibian tissues have long been used as a model for the study of basic physiological principles of epithelial ion and water transport. Recent progress with tissue cultures has provided information on the molecular structure of ion and water channels that can be applied to obtain a better understanding, at the molecular level, of ion and water balance strategies used by the wide variety of amphibian species. Terrestrial amphibians are more tolerant of dehydration than are other vertebrates and are able to store dilute urine in their urinary bladder. Toads appear to be able to detect the presence of water in their bladders in addition to the availability of water in their environment. Dehydrated toads are able to rehydrate very rapidly by the coordination of behavioral and physiological mechanisms to enhance cutaneous water absorption. The integration of behavior with cutaneous water gain, renal handling of ions and water and the role of the lymphatic system in overall water balance involves complex interactions between neural and hormonal factors. Experiments are summarized that describe the contribution of individual factors however much more information is needed before the nature of these interactions are fully understood.


πŸ“œ SIMILAR VOLUMES


Integrating quantum and molecular mechan
✍ Harrison, Robert W. πŸ“‚ Article πŸ“… 1999 πŸ› John Wiley and Sons 🌐 English βš– 284 KB πŸ‘ 1 views

A computer algorithm is developed for integrating density functional quantum mechanics into a molecular mechanics program. The Ε½ computationally infeasible aspects of the standard LCAO-MO approach the iterative calculation of eigenvectors and the requirement of orthogonal . expansions for the orbita

Mechanisms of osmoregulation in the gree
✍ Thompson, Guy A. πŸ“‚ Article πŸ“… 1994 πŸ› John Wiley and Sons 🌐 English βš– 544 KB

## Abstract The halotolerant alga, __D. salina__, offsets the high (up to 5 M) external NaCl concentration in its environment by maintaining a nearly equivalent level of intracellular glycerol. Cells experiencing sudden hypoosmotic shock respond initially by volume expansion and then convert glycer

Molecular mechanisms of nucleic acid int
✍ John M. Coffin πŸ“‚ Article πŸ“… 1990 πŸ› John Wiley and Sons 🌐 English βš– 573 KB

## Abstract There are three known mechanisms by which foreign DNA can be made a permanent part of the genome of an animal cell, and their properties are summarized in this report. Naked DNA introduced into cells is usually rapidly lost, but a small fraction can be integrated by illegitimate recombi