The Physiology of Contractile Vacuoles

1951 ◽  
Vol 28 (2) ◽  
pp. 203-214
Author(s):  
J. A. KITCHING
Keyword(s):  
Ethylene Glycol ◽  
Osmotic Pressure ◽  
Sea Water ◽  
Tap Water ◽  
Good Evidence ◽  
The Body ◽  
Body Volume ◽  
Dilute Solution ◽  
High Level ◽  
Osmoregulatory Mechanism

1. Evidence from osmotic experiments indicates that the amount of osmotically inactive material in the suctorian Podophrya is small, and that the internal osmotic pressure of the cytoplasm is approximately that of a 0-04 M solution of non-electrolyte. 2. When the internal osmotic pressure of Podophrya is raised to an abnormally high level by equilibration with a solution of ethylene glycol or with dilute sea water, and the organism is then transferred to tap water, the rate of vacuolar output is temporarily raised far above its normal value. The body swells only slightly. This is taken as good evidence for osmoregulation. 3. When Podophrya is placed in a dilute solution of sucrose the rate of vacuolar output (relative to the original rate in tap water) decreases rectilinearly with the concentration of sucrose used, reaching zero at about 0.04M. This is as would be required for good osmoregulation. 4. There is a slight lag in the response of the contractile vacuole to a change of medium. It is suggested that this delay in adjustment of the osmoregulatory mechanism must result in a slight change of body volume, which could be the basis for the control of vacuolar output.

scholarly journals The Physiology of Contractile Vacuoles

1934 ◽  
Vol 11 (4) ◽  
pp. 364-381
Author(s):  
J. A. KITCHING
Keyword(s):  
Fresh Water ◽  
Sea Water ◽  
Tap Water ◽  
Marine Species ◽  
The Body ◽  
Contractile Vacuole ◽  
Body Volume ◽  
Water Value ◽  
Contractile Vacuoles ◽  
Sustained Increase

1. The rate of output of fluid from the contractile vacuole of a fresh-water Peritrich Ciliate was decreased to a new steady value immediately the organism was placed in a mixture of tap water and sea water. The rate of output returned to its original value immediately the organism was replaced in tap water. The contractile vacuole was stopped when the organism was treated with a mixture containing more than 12 per cent, of sea water. 2. Transference of various species of marine Peritricha from 100 per cent, sea water to mixtures of sea water and tap water led to an immediate increase of the body volume to a new and generally steady value. Return of the organism to 100 per cent, sea water led to an immediate decrease of the body volume to its original value or less. 3. Marine Peritricha showed little change in rate of output when treated with concentrations of sea water between 100 and 75 per cent. In more dilute mixtures the rate of output was immediately increased, and then generally fell off slightly to a new steady value which was still considerably above the original (100 per cent. sea water) value. The maximum sustained increase was approximately x 80. Return of the organism to 100 per cent, sea water led to an immediate return of the rate of output to approximately its original value. 4. When individuals of some marine species were placed in very dilute concentrations of sea water, the pellicle was frequently raised up in blisters by the formation of drops of fluid underneath it, and the contractile vacuole stopped. 5. Evidence is brought forward to suggest that in the lower concentrations of sea water marine forms lost salts. 6. The contractile vacuole probably acts as an osmotic controller in fresh-water Protozoa. Its function in those marine Protozoa in which it occurs remains obscure.

The Physiology of Contractile Vacuoles

1948 ◽  
Vol 25 (4) ◽  
pp. 421-436
Author(s):  
J. A. KITCHING
Keyword(s):  
Osmotic Pressure ◽  
Sea Water ◽  
External Medium ◽  
External Solution ◽  
Pond Water ◽  
The Body ◽  
Contractile Vacuole ◽  
Effect Of Temperature ◽  
Body Volume ◽  
Sucrose Solutions

1. On transfer from sea water to dilute sea water, the marine peritrich ciliate Vorticella marina swells more rapidly at higher temperatures. 2. It is concluded that the permeability of the surface of V. marina to water is influenced by temperature, with a Q10 of very roughly 2·5-3·2. 3. The body volume of the fresh-water peritrich ciliate Carchesium aselli is maintained approximately constant when the organism is transferred to solutions of sucrose of concentrations up to about 0·04 M; in higher concentrations the organism shrinks. 4. The rate of output of the contractile vacuole of C. aselli decreases with increasing concentrations of sucrose in the external medium; the rate of output is very low in 0·05 M-sucrose. 5. From a consideration of the effects of sucrose solutions on the body volume and on the rate of vacuolar output it is concluded that the initial osmotic pressure of C. aselli normally exceeds that of the external pond water by about 0·04-0·05 M non-electrolyte. 6. The internal osmotic pressure of C. aselli is not materially increased by increase of temperature. 7. It is concluded that the increase in rate of vacuolar output, which accompanies increase of temperature, counterbalances an increased rate of osmotic uptake of water from the external medium, and that this increased rate of uptake is due to an effect of temperature on the permeability of the surface through which the water enters. 8. The rate of vacuolar output is temporarily much increased when C. aselli, which has been equilibrated in solutions of ethylene glycol, is returned to pond water. 9. It is suggested that the temperature and the osmotic pressure of the external solution largely determine the osmotic stress which is imposed on the organism, and that they thus influence the state of hydration of the protoplasm; in turn this may be supposed to determine the activity of the contractile vacuole.

Osmoregulation in the Larva of the Marine Caddis Fly, Philanisus Plebeius (Walk.) (Trichoptera)

1972 ◽  
Vol 57 (3) ◽  
pp. 821-838
Author(s):  
JOHN P. LEADER
Keyword(s):  
Sodium Chloride ◽  
Osmotic Pressure ◽  
Body Surface ◽  
Sea Water ◽  
Electrical Potential ◽  
Chloride Ion ◽  
Chloride Ions ◽  
The Body ◽  
Electrical Potential Difference ◽  
Caddis Fly

1. The larva of Philanisus plebeius is capable of surviving for at least 10 days in external salt concentrations from 90 mM/l sodium chloride (about 15 % sea water) to 900 mM/l sodium chloride (about 150 % sea water). 2. Over this range the osmotic pressure and the sodium and chloride ion concentrations of the haemolymph are strongly regulated. The osmotic pressure of the midgut fluid and rectal fluid is also strongly regulated. 3. The body surface of the larva is highly permeable to water and sodium ions. 4. In sea water the larva is exposed to a large osmotic flow of water outwards across the body surface. This loss is replaced by drinking the medium. 5. The rectal fluid of larvae in sea water, although hyperosmotic to the haemolymph, is hypo-osmotic to the medium, making it necessary to postulate an extra-renal site of salt excretion. 6. Measurements of electrical potential difference across the body wall of the larva suggest that in sea water this tissue actively transports sodium and chloride ions out of the body.

scholarly journals 908 PB 533 STUDIES ON NATURE OF SALT TOLERANCE IN OKRA

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 564b-564
Author(s):  
Kh. A. Okasha ◽  
R. M. Helal
Keyword(s):  
Salt Tolerance ◽  
Seed Germination ◽  
Plant Development ◽  
Sea Water ◽  
Saline Water ◽  
Tap Water ◽  
Total Yield ◽  
Gold Coast ◽  
Electronic Conductivities ◽  
High Level

Salt tolerance of four okra cutivars namely : white velvet ; Gold coast ; Balady and Eskandarani, were investigated during three different stages of plant development namely : seed germination, seedling and reproductive stages. At both first and second stages of plant development various concentrations of sea water (diluted with tap water) were used for irrigation while at the third stage, various saline water with different electronic conductivities were used for irrigation Results of these studies revealed that salinity reduced and delayed seed germination At this stage, white velvet cv. appeared to be tolerant to salinity. At the seedling stage, salinity generally reduced hash weight of plant for all tested cuitivars and Gold coast was the lead affected one At the reproductive stage, salinity reduced plant growth and total yield/plant but with different degrees depending upon cultivar In this respect, yield of both Gold coast and Balady was not greatly reduced at the high level of salinity The anatomical studies showed that salinity reduced xylem and phloem elements in okra roots depending upon both salinity level and cultivar Generally, the obtained results suggest that both Gold coast and Balady okra cultivars can considered as tolerant genotypes to salinity and recommended for cultivation in both and and semi-arid lands where salinity is considered a potential problem

scholarly journals Body volume modeling by linear features of the Irmen type cattle

2020 ◽  
Vol 50 (6) ◽  
pp. 106-114
Author(s):  
A. F. Petrov ◽  
E. V. Kamaldinov ◽  
O. D. Panferova ◽  
O. V. Efremova ◽  
V. A. Rogozin
Keyword(s):  
Regression Models ◽  
Complex Trait ◽  
The Body ◽  
Body Volume ◽  
Linear Regression Models ◽  
Linear Features ◽  
Volume Response ◽  
Volume Modeling ◽  
High Level

The results of modeling the variability of the complex trait "body volume" by linear traits measured on a 10-point scale in accordance with the current instructions for cattle grading of dairy and dairy-beef breeds are presented. The object of research is the complex indicator "body volume" of Irmen type cattle. The exterior of the livestock was evaluated by experts on a collegial basis. The models obtained made it possible to identify a group of exterior features associated with the variability of the studied trait and to identify errors in the work of the evaluators. The tasks were solved using multiple linear, polynomial, power and logarithmic regression models. It was found that multiple linear regression models accurately describe the norm reaction of the body volume response. Residue distribution diagrams made it possible to control the quality of appraisers' assessment and adjust their further work. The logarithmic model was marked as closest to linear. The residues in most cases turned out to be close to zero, which was explained by the low level of variability of the traits used. It was revealed that the use of different levels of power orders in modeling the variability of the body volume in points can lead to the emergence of biologically inexplicable relationships with such linear features as the location of the front teats, the location of the rear teats, attachment of the anterior lobes and the position of the bottom of the udder. The construction of the scatter diagram revealed a high level of variation in the residues and led to the conclusion that it was inexpedient to introduce power series models into the practical work of livestock breeders. The insignificant contribution of the studied linear features to the variation of the complex feature under study is shown. High intra-group variance in the construction of second- and fourth-order polynomial models was reflected in the lowest values of the Fisher criterion.

Hibernation and Osmoregulation in the Diamondback Terrapin Malaclemys Centrata Centrata (Latreille)

1973 ◽  
Vol 59 (1) ◽  
pp. 45-51
Author(s):  
M. GILLES-BAILLIEN
Keyword(s):  
Osmotic Stress ◽  
Blood Plasma ◽  
Osmotic Pressure ◽  
Fresh Water ◽  
Seasonal Variations ◽  
Sea Water ◽  
Tap Water ◽  
The Other ◽  
Diamondback Terrapin ◽  
Diamondback Terrapins

1. Two batches of diamondback terrapins have been kept for a whole year, one in sea water the other in tap water, and seasonal variations have been recorded in the composition and osmotic pressure of the blood plasma. 2. All year round the sea-water animals have a higher osmotic pressure and higher concentrations of Na, K, Cl and urea than fresh-water animals. It is in July, however, that these differences are the least marked. 3. The seasonal variations recorded are linked in particular to the conditions of osmotic stress imposed by the environment. 4. The results are discussed within the framework of hibernation and of the evolution among chelonians from fresh water to sea water.

The Adaptation of Gunda Ulvae to Salinity

1931 ◽  
Vol 8 (1) ◽  
pp. 82-94
Author(s):  
C. F. A. PANTIN
Keyword(s):  
Osmotic Pressure ◽  
Electric Conductivity ◽  
Fresh Water ◽  
Salt Concentration ◽  
Sea Water ◽  
Distilled Water ◽  
Dilute Solution ◽  
Dilute Solutions ◽  
The Moment ◽  
Limiting Value

1. The rate of loss of salts by the estuarine worm, Gunda ulvae, on transference from sea water to various dilute solutions has been studied by measurement of the electric conductivity of the solutions. 2. Salts are lost by the worms from the moment of immersion in dilute solutions. Conditions affecting the rate of loss of salts are discussed. 3. The relation between the amount of salts lost and the total electrolyte content of the worm was determined. It is shown that the worms only lose 25 per cent. of their salts during the time that they imbibe a volume of water from the dilute solution equal to their initial volume. 4. The limiting internal salt concentration of worms surviving in waters containing calcium is about 6-10 per cent. of the normal concentration in sea water. No such limiting value can be found for distilled water, since salts are lost continuously till cytolysis occurs. The significance of the limiting concentration is discussed. 5. The effect of osmotic pressure, pH, dilute solutions of NaCl, NaHCO3, glycerol, CaCl2 and CaCO3 are studied. The presence of calcium reduces the rate of loss of salts. Other factors do not seem to influence this rate. 6. The relation of calcium to the maintenance of normal permeability to water and salts in the worm, and the significance of this to the problem of migration into fresh water are discussed.

scholarly journals Adaptation to Changes of Salinity in the Polychaetes

1937 ◽  
Vol 14 (1) ◽  
pp. 56-70
Author(s):  
L. C. BEADLE
Keyword(s):  
Hydrostatic Pressure ◽  
Body Wall ◽  
Sea Water ◽  
Calcium Deficiency ◽  
Body Fluids ◽  
The Body ◽  
Concentration Curve ◽  
Body Volume ◽  
Weight Curve ◽  
Body Wall Muscles

1. Nereis diversicolor collected from the same locality at different times showed smaller weight increases in dilute sea water (25 per cent) during the winter than during the summer months. 2. In spite of great variations in the weight curve, the body fluid concentration curve was very constant. 3. The maintenance of hypertonic body fluids and the regulation of body volume are largely unconnected. 4. The lowering of the weight curve below that theoretically expected from the concentration curve cannot be attributed to passive salt loss through the body surface. It is suggested that this is due to the removal of fluid through the nephridia under the hydrostatic pressure produced by the contraction of the body wall muscles. 5. Animals previously subjected to dilute sea water, when placed in water isotonic with the body fluids, will increase the concentration of the latter. This result is more marked when the internal hydrostatic pressure is high. 6. The results suggest that the osmotic regulatory mechanism involves the removal by the nephridia of fluid hypotonic to the body fluids. But no direct evidence for this is available. 7. Calcium deficiency and cyanide in dilute sea water cause an increase of weight and ultimately inhibit the maintenance of hypertonic body fluids. Both these effects are reversible. 8. The mechanism by which body fluids are maintained hypertonic to the external medium is not sufficiently developed to be of survival value in the locality in which the animals were found. 9. The control of body volume is probably of greater importance. 10. The majority of the extra oxygen consumption in dilute sea water is not the result of osmotic work. It is suggested that it may be due to work done by the body wall muscles in resisting swelling.

The Osmoregulatory System of the Amoeba, Acanthamoeba Castellanii

1972 ◽  
Vol 57 (1) ◽  
pp. 55-76
Author(s):  
R. A. PAL
Keyword(s):  
Plasma Membrane ◽  
Polyethylene Glycol ◽  
Ethylene Glycol ◽  
Surface Membrane ◽  
Acanthamoeba Castellanii ◽  
Sodium Sulphate ◽  
The Body ◽  
Contractile Vacuole ◽  
Body Volume ◽  
Food Vacuoles

1. It is estimated that Acanthamoeba castellanii eliminates a volume of water equal to its body volume in about 15-30 min. About 7% of the vacuolar discharge enters the body by means other than osmosis through the surface membrane. Food vacuoles fusing with the contractile vacuole do not significantly affect the rate of output. 2. Vacuolar output declines with the age of culture so that during the stationary phase of growth it is about half of that during early log phase of growth. 3. The rate of output of the contractile vacuole decreases with an increase of concentration of a non-penetrating solute in the external medium and shows a rectilinear relationship up to 0.07 M concentration. A low residual output after 0.07 M may be due to food vacuoles and pinocytic vacuoles. 4. On the basis of vacuolar output the excess internal osmotic pressure and permeability constant of water has been estimated as 0.07 M non-electrolyte and 0.04µm min-1 atm.-1 respectively. 5. On the basis of vacuolar behaviour it is concluded that the relative permeabilities of the plasma membrane to different solutes follows this order: methyl alcohol > ethylene glycol > urea > glycerol. On certain assumptions the permeability of the plasma membrane to ethylene glycol has been estimated provisionally as 0.107 x 10-16 mol/sec/µm2/mol/l. 6. Vacuolar behaviour suggests that sodium chloride, sodium nitrate, sodium sulphate and potassium chloride, but not magnesium chloride and calcium chloride, pass into the cell freely. 7. Growth of populations of A. castellanii is almost normal in polyethylene glycol 600 up to 0.07 M concentration but in higher concentrations it is low. There are some indications of an increase in volume of A . castellanii in cultures of polyethylene glycol 600 up to 0.07 M concentration, but not in higher concentrations. For amoebae cultured in media containing polyethylene glycol 600 the rate of output of the contractile vacuole declines sharply with an increase of polyethylene glycol 600 up to 0.07 M concentration and then more gradually.

Active Transport and Sodium Fluxes at Moult in the Amphipod, Gammarus Duebeni

1969 ◽  
Vol 51 (3) ◽  
pp. 591-605
Author(s):  
A. P. M. LOCKWOOD ◽  
W. R. H. ANDREWS
Keyword(s):  
Fresh Water ◽  
Body Surface ◽  
Major Part ◽  
Sea Water ◽  
Sucrose Solution ◽  
The Body ◽  
Active Sodium ◽  
Sodium Influx ◽  
Sodium Uptake ◽  
High Level

1. The sodium fluxes of individual Gammarus duebeni, which moulted in sea water, have been followed daily from the morning following moult for at least 6 days. 2. Sodium influx from sea water declined from 15.1µM/animal/hr. on the first morning after moult to 1.7µM/animal/hr. by the tenth day after moult. 3. Sodium influx from 10 mM/l. NaCl plus sucrose solution isotonic with sea water declines from 4.48µM/animal/hr. to 0.14µM/animal/hr. in inter-moult animals. 4. Thionine inhibits over 90% of the influx from 10 mM/l NaCl plus isotonic sucrose on the first day after moult, and this, together with other evidence, suggests that the major part of the influx from this medium is due to active sodium uptake. The rate of active uptake is comparable with, or faster than, the rate of uptake by animals acclimatized to fresh water. 5. The influx occurs primarily across the body surface. It is suggested that the high level of sodium uptake is associated with the water uptake which occurs at moult.

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