Solute Secretion By The Tube Foot Epithelium In The Starfish Asterias Forbesi

1977 ◽  
Vol 68 (1) ◽  
pp. 35-43
Author(s):  
ROBERT D. PRUSCH
Keyword(s):  
Driving Force ◽  
Sea Water ◽  
Vascular System ◽  
External Environment ◽  
Coelomic Fluid ◽  
Active Secretion ◽  
Osmotic Concentration ◽  
Asterias Forbesi ◽  
K Secretion ◽  
Tube Feet

1. The K+ and Cl- levels and osmotic concentration of the tube feet fluid in intact starfish (Asterias forbesi) are higher than that in the external sea water or perivisceral (coelomic) fluid. 2. The increase in K+ in the fluid in the tube feet lumen is brought about by the active secretion of K+ by the tube feet epithelium. 3. No exchange of material from the external environment with the more distal portions of the water vascular system across the madreporite was observed in this study. 4. It is suggested that the fluid volume in the tube feet is maintained by active K+ secretion, by the tube feet epithelium, which creates an osmotic driving force for water into the lumen of the tube feet.

Hypo-Osmotic Urine in Nereis Diversicolor

1970 ◽  
Vol 53 (1) ◽  
pp. 101-108
Author(s):  
RALPH I. SMITH
Keyword(s):  
Baltic Sea ◽  
Sea Water ◽  
Coelomic Fluid ◽  
Osmotic Concentration ◽  
Nereis Diversicolor ◽  
Low Salinity

1. Nereis diversicolor, when regulating in water of low salinity, produces urine of lower osmotic concentration than the coelomic fluid. 2. The urine is significantly hypo-osmotic in 0.9-5.3 % sea water (Cl = 5-30 mM/l), and slightly hypo-osmotic in natural Baltic Sea water (17 % sea water; Cl = 95 mM/l). 3. The urine is probably iso-osmotic in 28 % sea water (Cl = 157 mM/l) and higher salinities.

The Regulation of Calcium and Magnesium in the Brackish Water Polychaete Nereis Diversicolor O.F.M

1970 ◽  
Vol 53 (2) ◽  
pp. 425-443
Author(s):  
C. R. FLETCHER
Keyword(s):  
Brackish Water ◽  
Calcium Concentration ◽  
Sea Water ◽  
Calcium Influx ◽  
Coelomic Fluid ◽  
Nereis Diversicolor ◽  
Active Uptake ◽  
Calcium And Magnesium ◽  
Electrochemical Potentials

1. Nereis diversicolor tolerates changes in the concentration of calcium and magnesium in its coelomic fluid proportional to the concentrations in the medium between chlorosities of 100-1000 mM/kg of water. 2. In lower salinities both ions are maintained relatively constant providing that the ratios of these ions to chloride in the medium are similar to the ratios in sea water. 3. The ratio of the concentration of calcium in the coelomic fluid to the concentration in the medium is a function of the salinity of the medium but not of the calcium concentration. 4. Both calcium and magnesium are at lower electrochemical potentials in the coelomic fluid than in the medium, indicating that it is not necessary to invoke active uptake. 5. The rate of calcium influx is substantial. 6. In salinities below to mM of chloride/kg of water the urine must contain less calcium than the coelomic fluid. 7. The significance of these results is discussed.

Size-Dependent Variation in the Evasive Behaviour of the Bivalve Mollusc Spisula Solidissima

1979 ◽  
Vol 78 (1) ◽  
pp. 59-75
Author(s):  
DAVID J. PRIOR ◽  
ANNE M. SCHNEIDERMAN ◽  
SHARON I. GREENE
Keyword(s):  
Receptive Fields ◽  
Bivalve Mollusc ◽  
Spisula Solidissima ◽  
Visceral Ganglion ◽  
Size Dependent ◽  
Boston University ◽  
Asterias Forbesi ◽  
The Mean ◽  
The Individual ◽  
Tube Feet

1. The evasive jump response of Spisula can be elicited by contact of the siphons with the tube feet of a starfish (Asterias forbesi). 2. The level of responsiveness varies with the size of the individual clam; small clams (2.0-5.0 cm) being very responsive, large clams (12.0-18.0 cm) being totally unresponsive. 3. The cell bodies of touch-sensitive neurones subserving the siphons are located in the visceral ganglion. The mean area of the receptive fields of these neurones in small clams is 33.8 mm2 and in large clams is 9.7 mm2. 4. In small clams the large proportion of the total siphon surface innervated by single touch-sensitive neurones results in considerable overlap of receptive fields. As a result of this overlap, numerous touch-sensitive neurones are activated by a point stimulus. 5. The variation in jump responsiveness of large and small clams is correlated with the size of the receptive fields of touch-sensitive neurones. Note: Present address: Department of Zoology, University of California, Berkeley, CA 04720. Present address: Boston University Marine Program, Woods Hole, MA 02543.

Urinary Bladder Volume and the Reabsorption of Water from the Urine of Crabs

1974 ◽  
Vol 60 (1) ◽  
pp. 167-181
Author(s):  
J. A. RIEGEL ◽  
A. P. M. LOCKWOOD ◽  
J. R. W. NORFOLK ◽  
N. C. BULLEID ◽  
P. A. TAYLOR
Keyword(s):  
Body Weight ◽  
Urinary Bladder ◽  
Blood Volume ◽  
Ethacrynic Acid ◽  
Sea Water ◽  
Carcinus Maenas ◽  
Bladder Volume ◽  
Active Secretion ◽  
51Cr Edta

1. Measurements have been made to determine the blood volume, bladder volume, clearance of 131I-sodium diatrizoate and U/H for diatrizoate in the crabs Carcinus maenas and Macropipus (Portunus) depurator. 2. Observed values of clearance blood volume and bladder volume in the two species at 18 °C were: Clearance (as % blood volume per day), Macropipus 56.1±14.5; Carcinus 27.1±5.8; Blood volume (as % body weight), Macropipus 21.0±4.0; Carcinus 19.2±3.0; Bladder volume (as % blood volume), Macropipus 12.1 ±5.0; Carcinus 11.0±8.0. 3. It is shown that the measured U/H differs from that to be expected if no reabsorption of water or secretion of diatrizoate occurs. 4. 14C-inulin and 51Cr-EDTA are excreted in an essentially similar manner to 131I-diatrizoate by Carcinus, implying that any active secretion of diatrizoate must be small in magnitude. 5. Injections of ethacrynic acid decrease the U/H ratio for diatrizoate relative to that in control Carcinus injected with sea water. In some Carcinus the concentration of diatrizoate in the urine comes to exceed that initially present in the blood. Both these points are taken, with 3, as support for the conclusion that water can be withdrawn from the primary urine of Carcinus.

The effect of external salinity on drinking rate and rectal secretion in the larvae of the saline-water mosquito Aedes taeniorhynchus

1977 ◽  
Vol 66 (1) ◽  
pp. 97-110
Author(s):  
T. J. Bradley ◽  
J. E. Phillips
Keyword(s):  
Sea Water ◽  
External Medium ◽  
Narrow Range ◽  
Saline Water ◽  
Fluid Secretion ◽  
Osmotic Concentration ◽  
Drinking Rate ◽  
Aedes Taeniorhynchus ◽  
External Salinity ◽  
Kinetics Of

1. The drinking rate of the saline-water mosquito larva Aedes taeniorhyncus (100 nl.mg-1.h-1) is unaffected by the salinity of the external medium, but is directly proportional to the surface area of the animal. 2. Haemolymph Na+, Mg2+, K+, Cl-, SO42- and osmotic concentrations were measured in larvae adapted to 10%, 100% and 200% seawater and were found to be regulated within a narrow range. 3. With the exception of potassium, ionic concentrations in rectal secretion were found to increase with increasing concentrations of the sea water in which larvae were reared. 4. The osmotic concentration of rectal secretion was unaffected by changes in haemolymph osmotic concentration but did rise when sodium or chloride concentrations of the haemolymph were increased. High levels of these ions also stimulated the rate of fluid secretion. 5. Transport of chloride and sodium by the rectum exhibits the kinetics of allosteric rather than classical enzymes.

scholarly journals Extracellular accumulation of proline, serine and trehalose in the haemolymph of osmoconforming brackish-water mosquitoes

1987 ◽  
Vol 129 (1) ◽  
pp. 231-238 ◽  
Author(s):  
M. A. Garrett ◽  
T. J. Bradley
Keyword(s):  
Organic Compounds ◽  
Brackish Water ◽  
Sea Water ◽  
Full Range ◽  
Culex Tarsalis ◽  
Osmotic Concentration

Larvae of Culex tarsalis, a mosquito, are capable of surviving and developing in dilutions of sea water ranging from 0 mosmol l-1 to 700 mosmol l-1. In waters more dilute than 400 mosmol l-1, the larvae osmoregulate, whereas in those more concentrated than 400 mosmol l-1, the osmotic strength of the haemolymph parallels that of the medium, i.e. the larvae osmoconform. Over the full range of external concentrations tested, the larvae regulate the levels of Na+, K+, Mg2+, Ca2+ and Cl- in the haemolymph. Analyses of haemolymph samples from larvae adapted to media of 50 mosmol l-1 or 600 mosmol l-1 indicate that the increase in haemolymph osmotic concentration observed in media above 400 mosmol l-1 is due to the accumulation of organic compounds, particularly proline, serine and trehalose.

Ultrafiltration in the Branchial Heart Appendage of Dibranchiate Cephalopods: A Comparative Ultrastructural and Physiological Study

1981 ◽  
Vol 92 (1) ◽  
pp. 23-35
Author(s):  
R. SCHIPP ◽  
F. HEVERT
Keyword(s):  
Basal Lamina ◽  
Peripheral Blood ◽  
Sea Water ◽  
Physiological Study ◽  
Coelomic Fluid ◽  
Octopus Vulgaris ◽  
Sepia Officinalis ◽  
Branchial Heart ◽  
Urine Formation

It is shown that ultrafiltration could be the first step in urine formation in Sepia officinalis and Octopus vulgaris. The organization of the podocytes indicates that ultrafiltration can occur through these cells. They have a thick basal lamina in contact with the peripheral blood lacunae, and the cell apices lie in infoldings of the lumen of the appendage. Comparison between the colloid-osmotic and the hydrostatic pressures of the fluids in the branchial heart and the pericardial coelom shows that an ultrafiltration can take place during the branchial heart systole as well as during a long phase of the diastole. Comparison of the osmolalities of blood, coelomic fluid, renal-sac fluid, and sea water shows that these species are hypoosmotic regulators.

Kidney Function in the Crab-Eating Frog (Rana Cancrivora)

1962 ◽  
Vol 39 (1) ◽  
pp. 167-177 ◽  
Author(s):  
KNUT SCHMIDT-NIELSEN ◽  
PING LEE
Keyword(s):  
East Asia ◽  
Glomerular Filtration ◽  
Kidney Function ◽  
Sea Water ◽  
Tubular Reabsorption ◽  
Urine Flow ◽  
South East Asia ◽  
Considerable Part ◽  
Osmotic Concentration ◽  
Full Strength

1. A study has been made of kidney function in the crab-eating frog, Rana cancrivora, of south-east Asia. 2. This frog can live in full-strength sea water; in such concentrated media its blood is slightly hypertonic to the medium, and a considerable part of the osmotic concentration is due to urea. 3. In concentrated media the excretion of urea is greatly diminished. This is not due to active tubular reabsorption of urea, but primarily to a low urine flow caused by increased tubular reabsorption of water and reduced glomerular filtration. 4. In concentrated media, as compared with dilute media, only a few percent of the filtered urea appears in the urine. 5. Osmoregulation of the crab-eating frog in sea water resembles that of elasmobranchs except in that there is no evidence of active tubular reabsorption of urea in the frog.

Further Observations on the Physiology of Salinity Adaptation in the Crab-Eating Frog (Rana Cancrivora)

1968 ◽  
Vol 49 (1) ◽  
pp. 185-193
Author(s):  
MALCOLM S. GORDON ◽  
VANCE A. TUCKER
Keyword(s):  
Sea Water ◽  
Short Circuit ◽  
Electrical Potential ◽  
Short Circuit Current ◽  
Ringer Solution ◽  
Osmotic Concentration ◽  
Green Toad ◽  
The Face ◽  
Solution Bathing ◽  
Toad Bufo

1. Total rates of urea loss from adult euryhaline crab-eating frogs (Rana cancrivora) adapted to various environmental salinities between fresh water and 80 % sea water increase as salinity increases above 40% sea water. Oxygen consumption is constant in rate in all salinities studied. 2. The presence of urea in the Ringer solution bathing isolated pieces of skin of frogs adapted to 60% sea water increases both the electrical potential and the inwardly directed short-circuit current across the skin. 3. In skeletal muscle cells addition of intracellular solutes maintains tissue hydration in the face of large increases in plasma osmotic concentration in high-salinity media. Changes in the intracellular urea and free amino acid concentrations are primarily responsible for increases in intracellular osmotic concentration. 4. Some implications of these observations are discussed and comparisons made with the euryhaline green toad, Bufo viridis.

scholarly journals Estabilidade osmótica dos fluídos celômicos de um pepino do mar (Holothuria grisea) e de uma estrela-do-mar (Asterina stellifera) (Echinodermata) expostos ao ar durante a maré baixa: um estudo de campo

2002 ◽  
Vol 31 ◽  
Author(s):  
DENILTON VIDOLIN ◽  
IVONETE A. SANTOS GOUVEA ◽  
CAROLINA A. FREIRE
Keyword(s):  
Body Wall ◽  
Sea Water ◽  
Weather Conditions ◽  
Coelomic Fluid ◽  
Slight Reduction ◽  
Air Exposure ◽  
Water Influx ◽  
Sunny Weather ◽  
Wall Permeability ◽  
Water Gain

Animais de entre-marés podem ser expostos ao ar durante a maré baixa, por pelo menos 1-2 horas. Os animais expostos ao ar são susceptíveis a perda de sal e/ou entrada de água durante chuva intensa, ou perda de água pela ação de dessecação do sol. A osmolalidade de amostras de fluido celômico obtidas do pepino-do-mar Holothuria grisea e da estrela-do-mar Asterina stellifera expostas ao ar, ou de animais controles imersos na água do mar adjacente foi determinada. As amostras foram obtidas imediatamente após a exposição ao ar, e novamente após uma hora de exposição ao ar, durante a maré baixa no campo, em tempo nublado, chuvoso, ou ensolarado, na Praia rochosa do Quilombo, Penha, Sul do Brasil. Uma hora de exposição a qualquer das condições climáticas indicadas não alterou a osmolalidade dos fluidos celômicos. Houve pequena redução nas osmolalidades dos fluidos celômicos durante a exposição ao ar com precipitação de chuva. Sugere-se que estes equinodermas possam imediatamente detectar sua exposição ao ar, e possam então reduzir a permeabilidade osmótica de sua parede do corpo, para evitar perda de água para o ar ou entrada de água/saída de sal durante a chuva. ABSTRACT Intertidal animals can be exposed to the air during low tide, for at least 1-2 hours. Animals exposed to the air are subject to salt loss (or water gain) from heavy rains or volume loss from the desiccating action of the sun. Coelomic fluid samples obtained from the sea-cucumber Holothuria grisea and the starfish Asterina stellifera exposed to the air or from control animals submerged in surrounding sea water have been assayed for osmolality. Samples were obtained right after air exposure and again after 1 hour of exposure to the air during low tide in the field, either under cloudy, rainy or sunny weather conditions, in the rocky beach of Quilombo, Penha, Southern Brazil. One hour of exposure to any of the conditions did not change coelomic fluid osmolalities. There was a slight reduction in coelomic fluid osmolalities upon air exposure during rainfall. It is suggested that these echinoderms can somehow immediately detect air exposure and reduce their body wall permeability to avoid water loss or water influx/salt loss during rainfall. RÉSUMÉ Animaux d’entre-marées peuvent êtres exposés a l’air libre pendant le reflux de la marée, pour environ une ou deux heures seulement. Ces animaux, quand exposés a l’air libre, sont susceptibles de perdre du sel et d’absorber de l’eau pendant une période de pluie intense. Par contre, ils peuvent perdre de l’eau si soumis a l’action de dessèchement due a une éxposition au soleil. On a réussi a determiner l’osmolalité d’échantillons du fluide celomique obtenus du Pépin-de-mer Holothuria grisea et de l’Étoile-de-mer Asterina stellifera exposés a l’air libre, e d’animaux-controles immergés dans l’eau de mer voisin. Les échantillons ont été obtenus tout de suite après l’exposition à l’air et, une seconde fois, après une heure d’exposition à l’air libre, pendant la durée de la marée basse, soit sous la pluie, soit au soleil ou soit sous un ciel ombrageux, à la plage rocailleuse de Quilombo, Penha, au sud du Brésil. Une heure d’éxposition à n’importe quelles conditions climatiques indiquées, n’ont pas pu altérer l’osmolalité des fluides celomiques, ce que sugère la conclusion que ces échinodermes peuvent détecter immédiatement sa exposition à l’air libre et peuvent tout de suite réduire la permeabilité osmotique de la membrane que recouvre son corps pour éviter perdre d’eau et, de la même façon, reduire l’absortion de l’eau pendant la pluie. On a observé une petite réduction de fluides celomiques pendant l’exposition a l’air, avec ocurrence de pluie.

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