The effect of osmotic hysteresis on volume regulation in Mytilus edulis

Gainey, Louis F.

doi:10.1016/0300-9629(87)90438-5

Cited by 12 publications

(1 citation statement)

References 11 publications

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“…As molluscs generally cannot control the water permeability of their integument very well, they undergo rapid changes in fluid volume in extracellular and intracellular compartments when exposed to environmental media with osmotic concentrations that are either hyperosmotic or hypoosmotic with respect to the body fluids of the animals. Such passive responses are very similar in marine bivalves (Gainey, 1987;Hosoi et al, 2003) Fig. 3.…”

Section: Discussionmentioning

confidence: 63%

Alanine, proline and urea are major organic osmolytes in the snailTheodoxus fluviatilisunder hyperosmotic stress

Wiesenthal

Müller

Harder

et al. 2019

Journal of Experimental Biology

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Hyperosmotic stress may result in osmotic volume loss from the body to the environment in animals that cannot control the water permeability of their integument. Euryhaline animals (which have a wide tolerance range of environmental salinities) have generally evolved the ability to counteract cell volume shrinkage by accumulating inorganic and organic osmolytes within their cells to balance internal and external osmolalities. Molluscs use very different combinations of amino acids and amino acid derivatives to achieve this goal. Theodoxus fluviatilis is a neritid gastropod that is distributed not only in limnic habitats in Europe but also in brackish waters (e.g. along the shoreline of the Baltic Sea). Animals from brackish sites survive better in high salinities than animals from freshwater locations. The results of the present study indicate that these differences in salinity tolerance cannot be explained by differences in the general ability to accumulate amino acids as organic osmolytes. Although there may be differences in the metabolic pathways involved in osmolyte accumulation in foot muscle tissue, the two groups of animals accumulate amino acid mixtures equally well when stepwise acclimated to their respective maximum tolerable salinity for extended periods. Among these amino acids, alanine and proline, as well as the osmolyte urea, hold a special importance for cell volume preservation in T. fluviatilis under hyperosmotic stress. It is possible that the accumulation of various amino acids during hyperosmotic stress occurs via hydrolysis of storage proteins, while alanine and proline are probably newly synthesised under conditions of hyperosmotic stress in the animals.

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Section: Discussionmentioning

confidence: 63%

Alanine, proline and urea are major organic osmolytes in the snailTheodoxus fluviatilisunder hyperosmotic stress

Wiesenthal

Müller

Harder

et al. 2019

Journal of Experimental Biology

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Osmoregulation and Excretion

Larsen

Deaton

Onken

et al. 2014

Comprehensive Physiology

182

141

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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 discussion of functions is based on a comparative approach analyzing mechanisms that have evolved in different taxonomic groups at biochemical, cellular and tissue levels and their integration in maintaining whole body water and ion homeostasis. The focus is on recent studies of adaptations and newly discovered mechanisms of acclimatization during transitions of animals between different osmotic environments. Special attention is paid to hypotheses about the diversity of cellular organization of osmoregulatory and excretory organs such as glomerular kidneys, antennal glands, Malpighian tubules and insect gut, gills, integument and intestine, with accounts on experimental approaches and methods applied in the studies. It is demonstrated how knowledge in these areas of comparative physiology has expanded considerably during the last two decades, bridging seminal classical works with studies based on new approaches at all levels of anatomical and functional organization. A number of as yet partially unanswered questions are emphasized, some of which are about how water and solute exchange mechanisms at lower levels are integrated for regulating whole body extracellular water volume and ion homeostasis of animals in their natural habitats. © 2014 American Physiological Society.

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Rapid and reversible tubulin tyrosination in human neutrophils stimulated by the chemotactic peptide, fMet‐Leu‐Phe

Rothwell

Nath

Wright

1993

Journal Cellular Physiology

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Neutrophil activation by specific stimuli, such as the oligopeptide chemotactic factor fMet-Leu-Phe (fMLF), is associated with an increased enzymatic addition of tyrosine to tubulin alpha-subunits, as measured by 14C tyrosine uptake. In studies using immunoblots we have found that this increased tyrosine uptake into tubulin in activated neutrophils reflects an increase in the proportion of cellular tubulin that is tyrosinated rather than simply an increase in the turnover of tyrosinated subunits. However, the increased accumulation of tyrosinated tubulin was also found to follow an initial depletion of tyrosinated tubulin and concomitant increase in detyrosinated tubulin between 0 and 60 sec following stimulation of neutrophils with fMLF. Immunogold electron microscopy studies of intact microtubules recovered from activated neutrophils demonstrated that these rapid changes in the relative content of tubulin isoforms in the cells were not associated with the formation or disappearance of microtubule microdomains composed of only one form of tubulin. Previously, we have shown that under conditions of fMLF-stimulated exocytosis there is an increased binding of neutrophil granules to endogenous microtubules. Since neutrophil activation by fMLF is associated with increased tyrosination of alpha-tubulin subunits, we speculated that rapid changes in the levels of tyrosinated tubulin in the microtubules of activated neutrophils might have a role in the regulation of granule-microtubule interactions. When the binding of purified neutrophil granules to reconstituted rat brain microtubules containing approximately 50% tyrosinated tubulin was measured by electron microscopy and compared with granule binding to microtubules that contained no detectable tyrosinated tubulin, granule-microtubule associations were found to be significantly favored by detyrosinated vs. tyrosinated tubulin. These findings indicate that interactions between cytoplasmic granules and microtubules in activated neutrophils may be modulated by rapid changes in the relative content of detyrosinated and tyrosinated tubulin in the microtubule network of the cells.

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The effect of osmotic hysteresis on volume regulation in Mytilus edulis

Cited by 12 publications

References 11 publications

Alanine, proline and urea are major organic osmolytes in the snailTheodoxus fluviatilisunder hyperosmotic stress

Alanine, proline and urea are major organic osmolytes in the snailTheodoxus fluviatilisunder hyperosmotic stress

Osmoregulation and Excretion

Rapid and reversible tubulin tyrosination in human neutrophils stimulated by the chemotactic peptide, fMet‐Leu‐Phe

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