Effect of Calcium on Survival Times of Rana temporaria L. Embryos at Low pH

1988 ◽  
Vol 2 (3) ◽  
pp. 297 ◽  
Author(s):  
C. P. Cummins
Keyword(s):  
Rana Temporaria ◽  
Low Ph ◽  
Survival Times

Physiological Correlates of Interspecific Variation in Acid Tolerance in Fish

1988 ◽  
Vol 136 (1) ◽  
pp. 243-258 ◽  
Author(s):  
J. FREDA ◽  
D. G. MCDONALD
Keyword(s):  
Yellow Perch ◽  
Acid Tolerance ◽  
Binding Activity ◽  
Low Ph ◽  
Whole Body ◽  
Salmo Gairdneri ◽  
Survival Times ◽  
Ion Regulation ◽  
Sodium Efflux ◽  
Na Efflux

This study investigated ion regulation in relation to water pH in three species of fish of differing tolerance to low pH (common shiners, Notropis cornutus, most sensitive; rainbow trout, Salmo gairdneri, intermediate; yellow perch, Perca flavescens, least sensitive). Increasing sensitivity to exposure to low pH was characterized by shorter survival times, greater losses of whole-body ions, more complete inhibition of Na+ uptake, and greater stimulation of Na+ efflux, the latter being the most important factor in determining survival. Interspecific variations in acid tolerance were also correlated with Na+ transport characteristics at circumneutral pH; Km was directly correlated and Vmax inversely correlated with acid tolerance. In addition, there were large qualitative differences among the species in the Ca2+-dependence of Na+ efflux. Sodium efflux induced by low pH was markedly Ca2+-dependent in both trout and shiners in a manner consistent with a simple competition between Ca2+ and H+ for gill binding sites. The increased sensitivity of shiners relative to trout was related to lowered Ca2+- binding activity. In contrast, Na+ efflux in perch was virtually unaffected by water [Ca2+]. Similarly, La3+ (a Ca2+ antagonist) stimulated higher Na+ losses from shiners than from trout, but had little effect upon perch. Ionic losses produced by saturating La3+ concentrations were generally lower than those produced by H+, suggesting that Ca2+ displacement is not the only mechanism for increased gill permeability at low pH. Nonetheless, the results obtained are consistent with the notion that acid tolerance may be related to Ca2+-binding activity in some species (e.g. trout and shiners) although not in others (e.g. perch).

The Effects of Low pH and Aluminum on Breeding Success in the Frog Rana temporaria

1992 ◽  
Vol 26 (4) ◽  
pp. 353 ◽  
Author(s):  
Robert C. Beattie ◽  
Richard Tyler-Jones
Keyword(s):  
Breeding Success ◽  
Rana Temporaria ◽  
Low Ph ◽  
Frog Rana Temporaria

Effects of pH on K depolarization and contracture in frog muscles

1979 ◽  
Vol 57 (2) ◽  
pp. 217-219
Author(s):  
Hrvoje Lorković
Keyword(s):  
Rana Temporaria ◽  
Rana Esculenta ◽  
Low Ph ◽  
Fiber Bundles ◽  
Bathing Solution ◽  
Mechanical Tension ◽  
Contraction Coupling ◽  
High K ◽  
Frog Species ◽  
Effects Of Ph

Membrane potential changes and mechanical tension provoked by 20 or 80 mM K at pH 8.0 or 4.5 were measured in muscle fiber bundles from Rana temporaria and Rana esculenta. The bathing solution contained Cl as the main anion. Low pH increased the depolarizing efficiency of high K to about the same degree in muscles of both species of frogs. The tension–[K] relationship was shifted toward lower [K] in muscles from R. temporaria and toward higher [K] in muscles from R. esculenta. It was concluded that the depolarization–contraction coupling was insensitive to pH changes in the former but not in the latter frog species.

The Mobilization of the Calcium Carbonate Deposits in the Endolymphatic Sacs of Metamorphosing Frogs

1966 ◽  
Vol 45 (2) ◽  
pp. 329-341
Author(s):  
J. B. PILKINGTON ◽  
K. SIMKISS
Keyword(s):  
Calcium Carbonate ◽  
Rana Temporaria ◽  
Morphological Changes ◽  
Environmental Water ◽  
Low Ph ◽  
The Other ◽  
Biochemical Data ◽  
Calcium Salts ◽  
Metamorphic Climax ◽  
Carbonate Deposits

1. Tadpoles of Rana temporaria have been reared in solutions of high and low pH with and without calcium. 2. Methods have been devised for analysing calcium, carbonate and phosphate in individual tadpoles. From these analyses it is possible to determine the distribution of calcium salts between the endolymphatic sacs and the skeleton throughout metamorphosis. 3. A system has been devised for correlating biochemical data with the morphological changes occurring during metamorphosis by means of a scale of ‘developmental days’. 4. The resorption of the endolymphatic deposits is not influenced by the acidity of the environmental solution. 5. Tadpoles reared in solutions containing added calcium had at any one stage in metamorphosis a larger reserve of endolymphatic calcium and a better ossified skeleton than the other tadpoles. 6. During metamorphic climax, when the tadpoles do not feed, the calcareous material in the endolymphatic sac is resorbed to provide calcium for the ossification of the skeleton and to make good any renal loss of calcium. 7. The resorption of endolymphatic calcium carbonate occurs in all tadpoles during metamorphic climax irrespective of the level of calcium in the environmental water. 8. The otoliths do not appear to be resorbed and the spinal portion of the deposits in the endolymphatic sacs may be more labile than those in the cranial regions.

Relationship between golgi apparatus and axonal reticulum in sympathetic ganglion cells

1978 ◽  
Vol 36 (2) ◽  
pp. 598-599
Author(s):  
J. Quatacker ◽  
W. De Potter
Keyword(s):  
Golgi Apparatus ◽  
Sympathetic Ganglion ◽  
Phosphotungstic Acid ◽  
Ganglion Cells ◽  
Low Ph ◽  
Dense Core ◽  
Dense Core Vesicles ◽  
Large Dense Core Vesicles ◽  
Cervical Ganglia ◽  
Axoplasmic Reticulum

Mucopolysaccharides have been demonstrated biochemically in catecholamine-containing subcellular particles in different rat, cat and ox tissues. As catecholamine-containing granules seem to arise from the Golgi apparatus and some also from the axoplasmic reticulum we examined wether carbohydrate macromolecules could be detected in the small and large dense core vesicles and in structures related to them. To this purpose superior cervical ganglia and irises from rabbit and cat and coeliac ganglia and their axons from dog were subjected to the chromaffin reaction to show the distribution of catecholamine-containing granules. Some material was also embedded in glycolmethacrylate (GMA) and stained with phosphotungstic acid (PTA) at low pH for the detection of carbohydrate macromolecules.The chromaffin reaction in the perikarya reveals mainly large dense core vesicles, but in the axon hillock, the axons and the terminals, the small dense core vesicles are more prominent. In the axons the small granules are sometimes seen inside a reticular network (fig. 1).

Transition (markov) models for the analysis of survival times in clinical research

1999 ◽  
Vol 28 (1) ◽  
pp. 165-176
Author(s):  
Sati Mazumdar ◽  
Kenneth Liu ◽  
Sang Ahnn ◽  
Patricia R. Houck ◽  
Charles F. Reynolds
Keyword(s):  
Clinical Research ◽  
Markov Models ◽  
Survival Times

Oxygen treatment after perinatal hypoxia-ischemia reduces neuronal damage at short survival times, but worsens injury with long-term survival

2005 ◽  
Vol 25 (1_suppl) ◽  
pp. S444-S444 ◽  
Author(s):  
Kristin M Noppens ◽  
J Regino Perez-Polo ◽  
David K Rassin ◽  
Karin N Westlund ◽  
Roderic Fabian ◽  
...  
Keyword(s):  
Neuronal Damage ◽  
Perinatal Hypoxia ◽  
Survival Times ◽  
Term Survival ◽  
Long Term Survival ◽  
Short Survival ◽  
Oxygen Treatment ◽  
Hypoxia Ischemia

Mechanism of Human Plasminogen Activation by Streptokinase and Human Plasmin

1964 ◽  
Vol 11 (01) ◽  
pp. 085-093
Author(s):  
W. F Blatt ◽  
JL Gray ◽  
H Jensen
Keyword(s):  
Proteolytic Activity ◽  
Low Ph ◽  
Plasminogen Activation ◽  
Sensitive Tool ◽  
Human Plasminogen

SummaryA sensitive tool has been described for measuring fibrinolysis in reconstituted systems using thrombelastography. Activator mixtures with no appreciable proteolytic activity can similarly be tested in this system when the fibrinogen utilized has sufficient plasminogen present. Exposure of human plasminstreptokinase mixtures formed at pH 7.0 to acid conditions produced a striking loss of activator activity which could not be ascribed to low pH lability of the components, nor to plasmin action on the SK at pH 2.0. This is additional evidence for the hypothesis that human plasmin interacts with SK to form a complex capable of converting human and bovine plasminogen to plasmin.

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