Osmetry. 2. Osmoregulation

Osmoregulation in marine mammals.

Osmoregulation in marine mammals has been investigated for over a century; however, a review of recent advances in our understanding of water and electrolyte balance and of renal function in marine mammals is warranted. The following topics are discussed: (i) kidney structure and urine concentrating ability, (ii) sources of water, (iii) the effects of feeding, fasting and diving, (iv) the renal...

Osmoregulation in Rhodobacter sphaeroides.

Betaine (N,N,N-trimethylglycine) functioned most effectively as an osmoprotectant in osmotically stressed Rhodobacter sphaeroides cells during aerobic growth in the dark and during anaerobic growth in the light. The presence of the amino acids L-glutamate, L-alanine, or L-proline in the growth medium did not result in a significant increase in the growth rate at increased osmotic strengths. The...

TRPV1 and Osmoregulation

Central control of systemic osmoregulation is the job of the organum vasculosum lamina terminalis (OVLT), located at the rostral ventral edge of the third ventricle. In this week’s Journal, Ciura and Bourque demonstrate that OVLT neurons are intrinsically osmosensitive because they express transient receptor potential vanilloid 1 (TRPV1) channels. The authors compared the neuronal activity of h...

Osmoregulation and excretion.

The article discusses advances in osmoregulation and excretion with emphasis on how multicellular animals in different osmotic environments regulate their milieu intérieur. Mechanisms of energy transformations in animal osmoregulation are dealt with in biophysical terms with respect to water and ion exchange across biological membranes and coupling of ion and water fluxes across epithelia. The ...

Osmoregulation in Halophilic Bacteria