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.

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.

Studies on the Physiology of Ascaris Lumbricoides

1952 ◽  
Vol 29 (1) ◽  
pp. 1-21
Author(s):  
A. D. HOBSON ◽  
W. STEPHENSON ◽  
L. C. BEADLE
Keyword(s):  
Osmotic Pressure ◽  
Body Fluid ◽  
Body Wall ◽  
Sea Water ◽  
External Medium ◽  
Chloride Concentration ◽  
The Body ◽  
Intestinal Fluid ◽  
The Difference ◽  
Saline Medium

1. The total osmotic pressure, electrical conductivity and chloride concentration of the body fluid of Ascaris lumbricoides and of the intestinal contents of the pig have been measured. 2. The results obtained agree with the observations of previous workers that Ascaris normally lives in a hypertonic medium and that it swells or shrinks in saline media which are too dilute or too concentrated. 3. Experiments comparing the behaviour of normal and ligatured animals show that both the body wall and the wall of the alimentary canal are surfaces through which water can pass. 4. 30% sea water has been used as a balanced saline medium for keeping the worms alive in the laboratory. This concentration was selected as being the one in which there was least change in the body weight of the animals exposed to it. 5. The osmotic pressure of the body fluid of worms kept in 30% sea water is approximately the same as in animals taken directly from the pig's intestine. The body fluid of fresh worms is hypertonic to 30% sea water and hypotonic to the intestinal fluid. In 30% sea water the normal osmotic gradient across the body wall is therefore reversed. 6. In 30% sea water the total ionic concentration (as measured by the conductivity) decreases slightly, but the chloride concentration increases by about 50%, although still remaining much below that of the external medium. 7. Experiments in which the animals were allowed to come into equilibrium with various concentrations of sea water from 20 to 40% show that there are corresponding changes in the osmotic pressure of the body fluid which is, however, always slightly above that of the saline medium. The conductivity also changes in a similar manner but is always less than that of the medium, and the difference between the two becomes progressively greater the more concentrated the medium. 8. The chloride concentration of the body fluid varies with but is always below that of the external medium, whether this is intestinal fluid or one of the saline media. In the latter the difference between the internal and external chloride concentrations is least in 20% sea water and becomes progressively greater as the concentration of the medium is increased. 9. Experiments with ligatured worms and with eviscerated cylinders of the body wall show that these share the capacity of the normal worm to maintain the chloride concentration of the body fluid below that of the environment. This power is not possessed by cylinders composed of the cuticle alone. 10. If the worms which have had their internal chloride concentration raised by exposure to 30% sea water are transferred to a medium composed of equal volumes of 30% sea water and isotonic sodium nitrate solution, the chloride concentration of the body fluid is reduced to a value below that of the external medium. This phenomenon is also displayed by worms ligatured after removal from the 30% sea water and, to an even more marked degree, by eviscerated cylinders of the body wall. 11. It is concluded that Ascaris is able to maintain the chloride concentration of the body fluid below that of the external medium by an process of chloride excretion against a concentration gradient, and that this mechanism is resident in the body wall, the cuticle being freely permeable to chloride.

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

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.

scholarly journals Aedes Aegypti: Energetics of Osmoregulation

1982 ◽  
Vol 101 (1) ◽  
pp. 135-141 ◽  
Author(s):  
H.A. EDWARDS
Keyword(s):  
Oxygen Consumption ◽  
Energy Cost ◽  
Sea Water ◽  
External Medium ◽  
Minimum Energy ◽  
Body Volume ◽  
Wet Weight ◽  
Minimum Energy Cost ◽  
Anal Papillae ◽  
Theoretical Minimum

1. Oxygen consumption of A. aegypti larvae, about 210 mul l g−1 tissue wet weight h−1, does not change when the salinity of the environment is changed. The number of mitochondria in the anal papillae, a salt-absorbing epithelium, increases as the external medium is diluted. There is no difference in oxygen consumption between isolated anal papillae in 0, 2 and 20% sea water. The papillae represent about 5% of body volume and their oxygen consumption is about 2% of the animal's total. The theoretical minimum energy cost of osmoregulation is four orders of magnitude smaller than the measured figure for the anal papillae alone. Osmoregulatory phenomena which would explain the recorded observations are discussed.

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 Pesticide Residue Monitoring on Agriculture in Indonesia

2020 ◽  
Vol 12 (2) ◽  
pp. 133
Author(s):  
Asep Nugraha Ardiwinata ◽  
Lin Nuriah Ginoga ◽  
Eman Sulaeman ◽  
Elisabeth Srihayu Harsanti
Keyword(s):  
Pesticide Residue ◽  
Pesticide Residues ◽  
Sea Water ◽  
Animal Feed ◽  
Pond Water ◽  
The Body ◽  
Central Java ◽  
Persistence Properties ◽  
North Sulawesi ◽  
Food Commodities

<p class="JSDLAbstrak"><strong>Abstra</strong><strong>ct. </strong>Most agricultural producers use pesticides to prevent pests and increase yield and quality of the food they grow. Pesticides can damage people’s health, and lead to birth defects (<em>teratogenic </em>in character) and death in humans and animals. Many of these chemical residues, especially derivatives of <em>organochlorine </em>pesticides, demonstrate dangerous bioaccumulation levels in the body and environment. The problems caused by<em> organochlorine</em> residues (<em>lindan, aldrin, dieldrin, endrin, heptachlor and DDT</em>) on agricultural lands that are still found today are generally the consequence of past usage that dates back to the1960s. Research on pesticide residues in Indonesia was carried out several years ago by various research institutes and universities and some of these results were collected between 1985 and 2017. Data distribution of the results on pesticide residues include in Aceh, North Sumatra, West Sumatra, Jambi, Bengkulu, Lampung, Banten, Jakarta, West Java, Central Java, East Java, Yogyakarta, Bali, South Kalimantan, North Sulawesi, South Sulawesi, Gorontalo, Maluku, and Papua. Most of the pesticide residue research has been conducted on vegetables. Pesticide residues were found in various commodities and matrices such as rice, soybeans, cow's milk, chicken eggs, fruit ingredients, vegetables, soil, paddy water, river water, lake water, pond water, sea water, water birds, animal feed, fish, frogs, lamb, birds, eggs, tea, and honey. Pesticide residues found were insecticide (<em>organochlorine, organophosphate, carbamate, pyrethroid</em>), and fungicide (<em>dimethomorp, fenobucarb, propineb, benomyl, carbendazim</em> and <em>thiametoxam). Organochlorine</em> insecticides have been banned, but the residues are still found today. This is due to the nature of <em>organochlorines</em> which have high persistence properties. Even though insecticide residues (<em>organophosphate, carbamate, pirethroid</em>) found in food commodities are still below the maximum residual limit (MRL), namely SNI 7313: 2008, but some close to MRL. Particularly for <em>organochlorine</em> residues in soil, water and plants insecticides must be monitored because they are persistent, toxic and accumulative. This paper aims to review of pesticide residues in various products including food, and the potential impact of pesticide residues on human health.</p><p class="JSDLAbstrak"> </p><p class="JSDLAbstrak"><strong>Abstrak. </strong>Sebagian besar produsen pertanian menggunakan pestisida untuk mencegah hama dan meningkatkan hasil dan kualitas makanan yang mereka tanam. Pestisida dapat merusak kesehatan manusia, dan bersifat <em>teratogenik</em> dan mematikan pada manusia dan hewan. Banyak dari residu kimia ini, terutama turunan pestisida <em>organoklorin</em>, menunjukkan tingkat bioakumulasi yang berbahaya dalam tubuh manusia dan lingkungan. Masalah tersebut disebabkan oleh residu <em>organoklorin</em> (<em>lindan, aldrin, dieldrin, endrin, heptachlor</em> dan <em>DDT</em>) yang digunakan sejak tahun 1960-an. Penelitian tentang residu pestisida di Indonesia dilakukan beberapa tahun yang lalu oleh berbagai lembaga penelitian dan universitas yang dikumpulkan antara tahun 1985 dan 2017. Distribusi data hasil residu pestisida tersebar di Aceh, Sumatera Utara, Sumatera Barat, Jambi, Bengkulu, Lampung, Banten, Jakarta, Jawa Barat, Jawa Tengah, Jawa Timur, Yogyakarta, Bali, Kalimantan Selatan, Sulawesi Utara dan Selatan, Gorontalo, Maluku, dan Papua. Penelitian yang telah dilakukan menemukan residu pestisida tidak hanya ditemukan di berbagai komoditas pertanian seperti beras, kedelai, susu sapi, telur ayam, bahan buah, sayuran tetapi juga pada tanah, sawah, air sungai, air danau, air kolam, air laut, burung air, pakan ternak, ikan, katak, domba, telur burung, teh, dan madu. Residu pestisida yang banyak ditemukan di lapangan adalah insektisida (<em>organoklorin, organofosfat, karbamat, piretroid</em>), dan fungisida (<em>dimethomorp, fenobucarb, propineb, benomyl, carbendazim</em> dan <em>thiametoxam</em>). Insektisida golongan <em>organoklorin </em>telah dilarang penggunaannya, namun residunya masih ditemukan hingga kini. Hal ini dikarenakan sifat organoklorin yang memiliki sifat persistensi yang tinggi. Residu insektisida (<em>organofosfat, karbamat, piretroid</em>) yang ditemukan di dalam komoditas pangan secara umum masih di bawah batas maksimum residu (BMR) yang mengacu pada standar nasional, yaitu SNI 7313: 2008, namun beberapa residu insektisida telah mendekati BMR. Khusus untuk residu insektisida golongan <em>organoklorin</em> di dalam tanah, air dan tanaman harus dipantau karena sifatnya yang persisten, beracun, dan akumulatif. Makalah ini bertujuan untuk mengkaji residu pestisida dalam berbagai produk termasuk makanan, dan dampak potensial residu pestisida pada kesehatan manusia.</p>

scholarly journals The Mechanism of Urine Formation in Invertebrates

1936 ◽  
Vol 13 (3) ◽  
pp. 309-328
Author(s):  
L. E. R. PICKEN
Keyword(s):  
Hydrostatic Pressure ◽  
Osmotic Pressure ◽  
Body Fluid ◽  
External Medium ◽  
Carcinus Maenas ◽  
Colloid Osmotic Pressure ◽  
Body Fluids ◽  
The Body ◽  
Small Animals ◽  
Urine Formation

1. In Carcinus maenas: (a) The blood may be hypertonic, isotonic or hypotonic to the external medium. (b) The urine may be hypertonic, isotonic or hypotonic to the blood, and its concentration may differ in the two antennary glands. (c) The hydrostatic pressure of the body fluid is c. 13 cm. of water. (d) The colloid osmotic pressure of the blood is c. 11 cm. of water. (e) The urine probably contains protein and has a colloid osmotic pressure of c. 3 cm. of water. 2. In Potamobius fluviatilis: (a) The blood is hypertonic to the external medium. (b) The urine is hypotonic to the blood but hypertonic to the external medium and its concentration may differ in the two antennary glands. (c) The hydrostatic pressure of the body fluid is c. 20 cm. of water. (d) The colloid osmotic pressure of the blood is c. 15 cm. of water. (e) The urine may contain protein and has a colloid osmotic pressure (calculated) of c. 2 cm. of water. 3. In Peripatopsis spp.: (a) The blood is hypertonic to the urine. (b) The hydrostatic pressure of the body fluid is c. 10 cm. of water. (c) The colloid osmotic pressure (calculated) of the blood is c. 5 cm. of water. (d) The urine may contain protein and has a colloid osmotic pressure (calculated) of c. 2.5 cm. of water. 4. It is concluded that filtration is possible and that secretion and resorption almost certainly occur in the formation of the urine. 5. A microthermopile is described. 6. Methods are described for measuring the hydrostatic pressure and the colloid osmotic pressures of the body fluids in small animals.

The responses of Scrobicularia plana (da Costa) to osmotic pressure changes

1957 ◽  
Vol 36 (3) ◽  
pp. 553-567 ◽  
Author(s):  
R. F. H. Freeman ◽  
F. H. Rigler
Keyword(s):  
Osmotic Pressure ◽  
Sea Water ◽  
External Medium ◽  
Natural Habitat ◽  
Scrobicularia Plana ◽  
Significant Difference ◽  
Pressure Changes

The osmotic pressure of the blood of Scrobicularia plana has been measured when the animal is exposed to diluted sea water, and observations made on the behaviour of the animal when exposed to solutions of different osmotic pressure.The blood osmotic pressure shows no significant difference to that of the external medium except in very low salinities. The external medium with which an animal in its natural habitat comes into equilibrium is represented by the water above the mud rather than the water contained in the mud. Open animals equilibrate to 80% sea water in 4–5 h and to 60% sea water in 5–6 h. The osmotic pressure of the blood of animals that remain closed in dilute media is decreased by as little as 1·5% per hour.

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.

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