The Physiology of Contractile Vacuoles

1954 ◽  
Vol 31 (1) ◽  
pp. 68-75
Author(s):  
J. A. KITCHING
Keyword(s):  
The Body ◽  
Contractile Vacuole ◽  
Body Volume ◽  
Sudden Increase ◽  
Small Decrease ◽  
Partial Restoration ◽  
Contractile Vacuoles

1. A study has been made of the effects of sudden changes of temperature on the contractile vacuole of the suctorian Discophrya piriformis Guilcher. 2. A sudden increase of temperature from below 15° C. by 5° or more causes a temporary fall in the rate of output, followed by a rise to a new level higher than the original. During the depression in activity the body swells slightly. 3. The vacuolar frequency increases immediately but briefly when the temperature is raised, falls steeply when the depression sets in, and when secretion is re-established rises again to a level above the original. 4. A sudden fall in temperature causes an immediate decrease in vacuolar frequency, followed by a partial restoration. The rate of output falls rather more slowly and remains low. In several cases a small decrease in body volume was observed. 5. It is suggested that the contractile vacuole is really contractile. 6. The observations on vacuolar frequency described in this paper are interpreted in terms of an inherent vacuolar rhythm which is modified by temperature and which is partially linked with rate of secretion.

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

1960 ◽  
Vol 37 (1) ◽  
pp. 73-82
Author(s):  
J. A. KITCHING ◽  
J. E. PADFIELD ◽  
M. H. ROGERS
Keyword(s):  
Body Surface ◽  
Normal Activity ◽  
The Body ◽  
Contractile Vacuole ◽  
Diffusion Constants ◽  
Contractile Vacuoles

1. The suctorian Discophrya collini (Root) has been subjected to D2O-H2O mixtures containing up to 99.7% D2O. 2. In 25% D2O or over there is a rapid but temporary shrinkage of the body. This shrinkage is difficult to estimate owing to the wrinkling of the body surface, but amounts to at least 10% in the undiluted (99.7%)D2O. 3. During the period of temporary shrinkage the contractile vacuole ceases activity. Normal activity is resumed when the normal volume is regained. In concentrations of D2O too low to cause shrinkage there is a temporary fall in the rate of vacuolar output. 4. Return to H2O leads to a brief but often very considerable rise in vacuolar output. 5. It is concluded that D2O penetrates less rapidly than H2O. A difference of at least 10% in the diffusion constants in the membrane would be required to explain our results. We cannot exclude this as unreasonable from our data, although an explanation based on differences in the equilibrium properties of D2O and H2O might also be invoked.

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.

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.

The Physiology of Contractile Vacuoles

1948 ◽  
Vol 25 (4) ◽  
pp. 406-420
Author(s):  
J. A. KITCHING
Keyword(s):  
Fresh Water ◽  
High Temperatures ◽  
Normal Level ◽  
Contractile Vacuole ◽  
High Rate ◽  
Body Volume ◽  
Slow Decline ◽  
Food Vacuoles ◽  
Contractile Vacuoles

1. The rate of output of the contractile vacuole in a fresh-water peritrich ciliate (Carchesium aselli) varies with temperature with a Q10 of about 2·5-3·2, or a µ of about 17,000, over the range 0-30° C. 2. There is a slow decline in output during exposure for several hours to high temperatures (25-30° C.). At still higher temperatures (34° C.) a high rate of output is maintained for a few minutes, but swelling and death rapidly ensue. 3. The frequency of uptake of food vacuoles also varies with temperature, increasing from 0 to about 24° C., but decreasing at higher temperatures. At about 0° C. and at temperatures above about 30° C. no food vacuoles are taken up and the adoral cilia remain extended and motionless. 4. No change in body volume could be detected during exposure to high temperatures (25-30° C.) for two or more hours, even though the rate of vacuolar output was increased to three or four times its normal level at 15° C. It is concluded that the rate of uptake of water from the outside medium must have been increased correspondingly. 5. It is suggested that temperature affects the permeability of the organism to water, and that the rate of vacuolar output is adjusted accordingly, although on the evidence so far presented other explanations are possible.

scholarly journals The Physiology Of Contractile Vacuoles

1936 ◽  
Vol 13 (1) ◽  
pp. 11-27
Author(s):  
J. A. KITCHING
Keyword(s):  
Cell Membrane ◽  
Body Surface ◽  
Salt Concentration ◽  
Sea Water ◽  
Cane Sugar ◽  
The Body ◽  
Contractile Vacuole ◽  
Body Volume ◽  
Oxidative Process ◽  
Low Concentrations

1. There was no change in the body volume of marine Peritricha subjected to reductions in the salt concentration of the medium, so long as the osmotic pressure of the medium was kept constant by the addition of urea, glycerol, or cane-sugar. In mixtures of isotonic non-electrolytes with sea water the rate of vacuolar output was decreased--more so in the case of urea than of glycerol. It is concluded that the cell membrane is relatively impermeable to urea, glycerol, and cane-sugar, and also to neutral salts. 2. Excretory substances could not be produced in sufficient quantity to attract water into the contractile vacuole by osmosis at the rate observed. The process of diastole therefore involves "secretion" of water by the vacuolar walls. 3. Cyanide and sulphide in very low concentrations rapidly caused a great reduction in the rate of output of the contractile vacuole of marine Peritricha. In the case of cyanide this effect was rapidly reversible. Alcohols and urethane only decreased the rate of vacuolar output when present in much higher concentrations. It is suggested that possibly vacuolar activity depends directly on an oxidative process. 4. When marine Peritricha were transferred from dilute sea water to dilute sea water of the same concentration+cyanide M/200 or M/500 (the pH being carefully controlled), the contractile vacuole was completely or almost completely stopped, and the body increased in volume. When the organism was transferred back to dilute sea water of the same concentration without cyanide, the contractile vacuole became active again and the body decreased in volume until a new steady value was attained which was rather below the value in dilute sea water before cyanide treatment. 5. The increase in body volume consequent on treatment with cyanide was greater the more dilute was the sea water. For sea water of concentrations of 100-75 per cent, no swelling was detectable when the organism was treated with cyanide. 6. The rate of output of the contractile vacuole is sufficiently great to account for the decrease in body volume during recovery from cyanide. 7. The permeability of the body surface to water is estimated as 0.05-0.10 cubic micra per square micron per atmosphere per minute.

Muscle strain histories in swimming milkfish in steady and sprinting gaits

1999 ◽  
Vol 202 (5) ◽  
pp. 529-541 ◽  
Author(s):  
S.L. Katz ◽  
R.E. Shadwick ◽  
H.S. Rapoport
Keyword(s):  
White Muscle ◽  
Beat Frequency ◽  
The Body ◽  
Body Volume ◽  
Implicit Assumption ◽  
Muscle Strain ◽  
Body Movements ◽  
Wide Range ◽  
Speed Range ◽  
Local Body

Adult milkfish (Chanos chanos) swam in a water-tunnel flume over a wide range of speeds. Fish were instrumented with sonomicrometers to measure shortening of red and white myotomal muscle. Muscle strain was also calculated from simultaneous overhead views of the swimming fish. This allowed us to test the hypothesis that the muscle shortens in phase with local body bending. The fish swam at slow speeds [U<2.6 fork lengths s-1 (=FL s-1)] where only peripheral red muscle was powering body movements, and also at higher speeds (2. 6>U>4.6 FL s-1) where they adopted a sprinting gait in which the white muscle is believed to power the body movements. For all combinations of speeds and body locations where we had simultaneous measurements of muscle strain and body bending (0.5 and 0.7FL), both techniques were equivalent predictors of muscle strain histories. Cross-correlation coefficients for comparisons between these techniques exceeded 0.95 in all cases and had temporal separations of less than 7 ms on average. Muscle strain measured using sonomicrometry within the speed range 0.9-2.6 FL s-1 showed that muscle strain did not increase substantially over that speed range, while tail-beat frequency increased by 140 %. While using a sprinting gait, muscle strains became bimodal, with strains within bursts being approximately double those between bursts. Muscle strain calculated from local body bending for a range of locations on the body indicated that muscle strain increases rostrally to caudally, but only by less than 4 %. These results suggest that swimming muscle, which forms a large fraction of the body volume in a fish, undergoes a history of strain that is similar to that expected for a homogeneous, continuous beam. This has been an implicit assumption for many studies of muscle function in many fish, but has not been tested explicitly until now. This result is achieved in spite of the presence of complex and inhomogeneous geometry in the folding of myotomes, collagenous myosepta and tendon, and the anatomical distinction between red and white muscle fibers.

VALIDITY OF THREE-DIMENSIONAL PHOTONIC SCANNING TECHNIQUE FOR ESTIMATING PERCENT BODY FAT

2013 ◽  
pp. 1-6
Author(s):  
K. SHITARA ◽  
H. KANEHISA ◽  
T. FUKUNAGA ◽  
T. YANAI ◽  
Y. KAWAKAMI
Keyword(s):  
Body Fat ◽  
Lung Volume ◽  
Three Dimensional ◽  
The Body ◽  
Percent Body Fat ◽  
Body Volume ◽  
Mean Values ◽  
Significant Difference ◽  
Human Body Surface ◽  
Estimated Error

Background:Three-dimensional photonic scanning (3DPS) was recently developed to measuredimensions of a human body surface. Objective:The purpose of this study was to explore the validity of bodyvolume measured by 3DPS for estimating the percent body fat (%fat). Design, setting, participants, andmeasurement:The body volumes were determined by 3DPS in 52 women. The body volume was corrected forresidual lung volume. The %fat was estimated from body density and compared with the corresponding referencevalue determined by the dual-energy x-ray absorptiometry (DXA). Results:No significant difference was foundfor the mean values of %fat obtained by 3DPS (22.2 ± 7.6%) and DXA (23.5 ± 4.9%). The root mean squareerror of %fat between 3DPS and reference technique was 6.0%. For each body segment, there was a significantpositive correlation between 3DPS- and DXA-values, although the corresponding value for the head was slightlylarger in 3DPS than in DXA. Residual lung volume was negatively correlated with the estimated error in %fat.Conclusions:The body volume determined with 3DPS is potentially useful for estimating %fat. A possiblestrategy for enhancing the measurement accuracy of %fat might be to refine the protocol for preparing thesubject’s hair prior to scanning and to improve the accuracy in the measurement of residual lung volume.

First report of Epistylis unioi Gong 1986 (Sessilida: Epistylididae) infecting fry of Pelteobagrus fulvidraco in Hubei, China

Zootaxa ◽  
2012 ◽  
Vol 3556 (1) ◽  
pp. 80 ◽  
Author(s):  
MING LI ◽  
WEIDONG LI ◽  
XIANPING GE ◽  
CHONG WANG ◽  
LIN ZHANG ◽  
...  
Keyword(s):  
Skin Lesions ◽  
Hubei Province ◽  
The Body ◽  
Contractile Vacuole ◽  
Central China ◽  
Pelteobagrus Fulvidraco ◽  
Fish Hatchery ◽  
The Relationship ◽  
Lake Fish

The peritrich Epistylis unioi Gong, 1986 was collected from fry of Pelteobagrus fulvidraco during parasite surveys at Hon-ghu Lake Fish Hatchery, Hubei Province, central China in May 2010 and redescribed. Some revisions were done basedon live, silver-impregnated, and SEM specimens. The zooid is elongated and somewhat vase-like in shape, measuring56–88 × 22–38 µm in vivo. A single contractile vacuole is apically located slightly below the peristome disc. The macro-nucleus is horseshoe-shaped, always transversely situated at the foreside of the body. Haplokinety (H) and polykinety (Po)complete one and one-half circuits on the peristome before entering the infundibulum, with a distal kinetal fragment pres-ent at the distal end. Silverline system consists of 37–45 pellicular striations between peristome and aboral trochal band(TB), and of 26–33 between TB and scopula. Colony is asymmetrically and dichotomously branched, usually with onlytwo levels of branches. In addition, the telotrochs of E. unioi were also observed and its structures were described herein.Besides, obvious skin lesions caused by the ringlike base of E. unioi were detected and the relationship between these epizooites and their hosts was briefly discussed as well.

Modelling skin surface areas involved in water transfer in the Palmate Newt (Lissotriton helveticus)

2014 ◽  
Vol 92 (8) ◽  
pp. 707-714 ◽  
Author(s):  
Thomas Wardziak ◽  
Laurent Oxarango ◽  
Sébastien Valette ◽  
Laurent Mahieu-Williame ◽  
Pierre Joly
Keyword(s):  
Surface Area ◽  
Skin Surface ◽  
Water Transfer ◽  
The Body ◽  
Body Volume ◽  
3D Analysis ◽  
Evaporative Water ◽  
Surface Areas ◽  
Lissotriton Helveticus ◽  
Palmate Newt

Magnetic resonance imaging (MRI) based 3D reconstructions were used to derive accurate quantitative data on body volume and functional skin surface areas involved in water transfer in the Palmate Newt (Lissotriton helveticus (Razoumovsky, 1789)). Body surface area can be functionally divided into evaporative surface area that interacts with the atmosphere and controls the transepidermal evaporative water loss (TEWL); ventral surface area in contact with the substratum that controls transepidermal water absorption (TWA); and skin surface area in contact with other skin surfaces when amphibians adopt water-conserving postures. We generated 3D geometries of the newts via volume-rendering by a “segmentation” process carried out using a graph-cuts algorithm and a Web-based interface. The geometries reproduced the two postures adopted by the newts, i.e., an I-shaped posture characterized by a straight body without tail coiling and an S-shaped posture where the body is huddled up with the tail coiling along it. As a guide to the quality of the surface area estimations, we compared measurements of TEWL rates between living newts and their agar replicas (reproducing their two postures) at 20 °C and 60% relative humidity. Whereas the newts did not show any physiological adaptations to restrain evaporation, they expressed an efficient S-shaped posture with a resulting water economy of 22.9%, which is very close to the 23.6% reduction in evaporative surface area measured using 3D analysis.

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