The Relative Losses of Sodium in the Urine and Across the Body surface in the Amphipod, Gammarus Duebeni

1965 ◽  
Vol 42 (1) ◽  
pp. 59-69
Author(s):  
A. P. M. LOCKWOOD
Keyword(s):  
Body Surface ◽  
Sea Water ◽  
Average Rate ◽  
The Body ◽  
High Rate ◽  
Water Turnover ◽  
Urine Production ◽  
Sodium Loss ◽  
And Diffusion ◽  
Total Sodium

1. The relative contributions of urine production and diffusion across the body surface to the loss of sodium from the body of the amphipod Gammarus duebeni have been investigated. 2. When the urine is isotonic to the blood some 80% of the total sodium loss is via the urine. 3. As the gradient between blood and medium is increased in dilute media production of urine hypotonic to the blood counteracts the tendency for sodium loss to increase. 4. In consequence, the average rate of sodium uptake at the body surface by animals acclimatized to 2% sea water needs to be only about twice that of animals acclimatized to 50% sea water. 5. It is suggested that the conservation of ions within the body by the production of hypotonic urine is likely to be found to be a common feature of the smaller brackish water crustacea, especially those with a high rate of water turnover.

Sodium Regulation in the Fresh-Water Amphipod, Gammarus Pulex (L.)

1967 ◽  
Vol 46 (3) ◽  
pp. 499-518
Author(s):  
D. W. SUTCLIFFE
Keyword(s):  
Fresh Water ◽  
Body Surface ◽  
Loss Rate ◽  
Sodium Concentration ◽  
The Body ◽  
Uptake Mechanism ◽  
Sodium Influx ◽  
Sodium Uptake ◽  
Sodium Loss ◽  
Total Sodium

1. Sodium influx and loss rates in Gammarus pulex were measured at constant temperatures. The sodium loss rate was immediately influenced by a change in temperature, with a Q10 of 1.5 to 2.0 at temperatures between 0.3 and 21.5° C. The sodium influx rate is apparently influenced in the same way. 2. The sodium uptake mechanism in G. pulex from three localities was half-saturated at an external concentration of 0.10-0.15 mM/l. sodium. 3. The total sodium loss rate remained approximately constant in animals acclimatized to the range of external concentrations from 2 to about 0.2 mM/l. sodium. 18% of the sodium was lost in urine with a sodium concentration estimated at 30-50 mM/l. The remainder of the sodium loss was due to diffusion across the body surface. 4. In animals acclimatized to concentrations below about 0.2 mM/l. sodium the sodium loss rate was reduced, due to (a) a lower diffusion rate following a fall in the blood sodium concentration, and (b) the elaboration of a more dilute urine. 5. There was a very close association between changes in the blood sodium concentration, the elaboration of a very dilute urine, and the rate of sodium uptake at the body surface. The results indicate that a fall in the blood sodium concentration leads to simultaneous activation of the sodium uptake mechanisms at the body surface and in the antennary glands. 6. It is estimated that, by producing a dilute urine, total sodium uptake in G. pulex is shared equally between the renal uptake mechanism and the mechanism situated at the body surface. 7. In sea-water media G. pulex drinks and expels fluid from the gut. In a medium slightly hyperosmotic to the normal blood concentration the amount imbibed was equal to the normal rate of urine flow when in fresh water.

Water Uptake and Loss in Relation to the Salinity of the Medium in the Amphipod Crustacean Gammarus Duebeni

1973 ◽  
Vol 58 (1) ◽  
pp. 149-163
Author(s):  
A. P. M. LOCKWOOD ◽  
C. B. E. INMAN
Keyword(s):  
Body Surface ◽  
Sea Water ◽  
Tritiated Water ◽  
Prima Facie ◽  
Urine Flow ◽  
The Body ◽  
Osmotic Gradient ◽  
Prima Facie Case ◽  
Urine Production ◽  
Water Saturated

1. The water fluxes across the body surface and the rate of urine production have been studied in the euryhaline amphipod Gammarus duebeni. 2. Urine flow rates (fPOs) have been determined from measurements of loss of [131I]sodium diatrizoate from the body, and the expected urine flow (fPdiff) has been calculated from determinations of the osmotic gradient between blood and medium and the flux of tritiated water. 3. For animals in 2% and 40% sea water the ratio fPOs/fPdiff are 1.16 and 1.44 respectively, and thus approximate fairly closely to unity. This implies that in these media the water subsequently excreted as urine enters the body by osmosis and that there is little interference with the free diffusion of water at the body surface due to passage through long pores or across unstirred layers. 4. In sea water the ratio fPOs/fPdiff is normally (assuming an osmotic gradient of 10 m-osmoles) almost twice unity but urine production is approximately halved when the animals are exposed to sea water saturated with an inhibitor of active sodium uptake (thionine). 5. It is suggested that there is a prima facie case for assuming that part of the fluid subsequently excreted by this species, when in sea water, is taken into the body initially by a process dependent upon active ion transport.

Studies on Ionic Regulation in Carcinus Maenas (L.)

1961 ◽  
Vol 38 (1) ◽  
pp. 135-152
Author(s):  
J. SHAW
Keyword(s):  
Body Weight ◽  
Sea Water ◽  
Carcinus Maenas ◽  
Sodium Concentration ◽  
Sodium Balance ◽  
Uptake Mechanism ◽  
Sodium Influx ◽  
Urine Production ◽  
Sodium Loss ◽  
Total Sodium

1. The mechanism of sodium balance in Carcinus maenas has been investigated. 2. Measurements of sodium outflux showed no evidence of a decrease in surface permeability to sodium in dilute sea water. 3. The rate of urine production in normal sea water was 3.6% body weight per day and the sodium loss through the urine was insignificant compared with the total sodium loss. In 40% sea water the urine rate was increased to 30% body weight per day and the loss in the urine accounted for 20% of the total loss. 4. Measurements of sodium influx and calculation of the active component showed that the active uptake mechanism was fully saturated at all external concentrations in which the animals could survive. 5. Regulation of the blood sodium concentration is effected largely by the activation of the sodium uptake mechanism. This prevents the blood concentration falling below a critical level as long as the external concentration itself is not too low.

Sodium Regulation in the Amphipod Gammarus Duebeni From Brackish-Water and Fresh-Water Localities in Britain

1967 ◽  
Vol 46 (3) ◽  
pp. 529-550 ◽  
Author(s):  
D. W. SUTCLIFFE
Keyword(s):  
Fresh Water ◽  
Body Surface ◽  
Brackish Water ◽  
Loss Rate ◽  
Sea Water ◽  
The Body ◽  
Sodium Ions ◽  
Sodium Uptake ◽  
Sodium Loss ◽  
Sodium Regulation

1. A quantitative study of sodium influx and loss rates was made on Gammarus duebeni obtained from brackish-water localities. Both influx and loss rates were immediately doubled by a rise in temperature from 10 to 20° C. 2. It is estimated that when animals are fully acclimatized to a series of media decreasing from 50 to 2% sea water the rate of sodium uptake at the body surface is doubled to balance the rate of sodium loss, which is also doubled. The increased loss rate is due equally to an increase in the rate of diffusion across the body surface and to loss in hypotonic urine containing about 160-190 mM/l. sodium. Diffusion losses normally account for at least 35% of the total losses, even when the urine is isotonic with the blood. 3. The sodium-transporting system at the body surface is fully saturated at an external concentration of about 10 mM/l. NaCl (2% sea water). The system has a low affinity for sodium ions and is only half-saturated at 1.5-2.5 mM/l. sodium. The overall rate of uptake is increased to its maximum rate to balance sodium losses when in fresh water. 4. When acclimatized to fresh water (0.25 mM/l. NaCl) the sodium loss rate is greatly reduced. This was partly due to a lower rate of diffusion across the body surface following a fall in the blood sodium concentration, and mainly due to elaboration of a very dilute urine. 5. It is suggested that increases in sodium uptake in the antennary glands, resulting in a hypotonic urine, are linked with increases in uptake at the body surface. Both uptake systems are possibly activated by a single internal regulator responding to changes in the blood concentration. 6. Sodium regulation at concentrations below 10 mM/l. NaCl was examined in G. duebeni obtained from fresh-water streams on the Lizard peninsula, the Kintyre peninsula, and the Isle of Man. The regulation of sodium uptake and loss is very similar to regulation in brackish-water animals, and the sodium-transporting system has the same low affinity for sodium ions at concentrations below about 10 mM/l. 7. It is suggested that fresh-water localities in north-west Europe, excluding Ireland, have been colonized from brackish water without any modifications in the sodium-regulatory mechanism. But the fresh-water animals tolerate very low sodium concentrations better than brackish-water animals. This is apparently due to natural selection of individuals in which the sodium uptake rate is higher than the average uptake rate in brackish-water animals.

Sodium Regulation and Adaptation to Fresh Water in Gammarid Crustaceans

1968 ◽  
Vol 48 (2) ◽  
pp. 359-380
Author(s):  
D. W. SUTCLIFFE
Keyword(s):  
Body Weight ◽  
Fresh Water ◽  
Body Surface ◽  
Sea Water ◽  
Sodium Concentration ◽  
The Body ◽  
Outward Diffusion ◽  
Gammarus Zaddachi ◽  
Freshwater Habitats ◽  
Sodium Regulation

1. Sodium uptake and loss rates are given for three gammarids acclimatized to media ranging from fresh water to undiluted sea water. 2. In Gammarus zaddachi and G. tigrinus the sodium transporting system at the body surface is half-saturated at an external concentration of about 1 mM/l. and fully saturated at about 10 mM/l. sodium. In Marinogammarus finmarchicus the respective concentrations are six to ten times higher. 3. M. finmarchicus is more permeable to water and salts than G. zaddachi and G. tigrinus. Estimated urine flow rates were equivalent to 6.5% body weight/hr./ osmole gradient at 10°C. in M. finmarchicus and 2.8% body weight/hr./osmole gradient in G. zaddachi. The permeability of the body surface to outward diffusion of sodium was four times higher in M. finmarchicus, but sodium losses across the body surface represent at least 50% of the total losses in both M. finmarchicus and G. zaddachi. 4. Calculations suggest that G. zaddachi produces urine slightly hypotonic to the blood when acclimatized to the range 20% down to 2% sea water. In fresh water the urine sodium concentration is reduced to a very low level. 5. The process of adaptation to fresh water in gammarid crustaceans is illustrated with reference to a series of species from marine, brackish and freshwater habitats.

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.

Tick Defense Strategies in Bison: The Role of Grooming and Hair Coat

Behaviour ◽  
1998 ◽  
Vol 135 (6) ◽  
pp. 693-718 ◽  
Author(s):  
Michael Mooring ◽  
William Samuel
Keyword(s):  
Body Surface ◽  
Cervus Elaphus ◽  
Attachment Site ◽  
The Body ◽  
Bison Bison ◽  
High Rate ◽  
Larval Feeding ◽  
Physical Barrier ◽  
Hair Coat ◽  
Winter Tick

AbstractGrooming behaviour, and its effectiveness in controlling infestation by the winter tick (Dermacentor albipictus), was studied for plains bison (Bison bison bison) in Elk Island National Park, Alberta, Canada from October 1995 through June 1996. Bison had few ticks (mean, 133 ticks per animal; 0.009 ticks per cm2), particularly in comparison with smaller sympatric cervids (moose, Alees alees; elk, Cervus elaphus; and white-tailed deer, Odocoileus virginianus), suggesting that tick defense in bison is highly effective. Bison performed grooming or grooming-like behaviours (oral grooming, scratching, rubbing, and wallowing) at a high rate during October, when winter tick larvae were blood feeding, but groomed very little from November to April, when nymphal and adult ticks predominated. Grooming in October probably removed many larval ticks while they were still unattached and traversing the body surface in search of an attachment site. Because bison groomed at the highest rate during the larval feeding period, when they were subjected to the lowest intensity of tick stimulation, grooming in bison appears to be centrally programmed rather than stimulus driven. This might be the only time ticks are vulnerable to grooming activity because bison have an extremely thick hair coat (a morphological adaptation to extreme cold), which probably serves as a physical barrier to infestation by ticks. The tightly packed mat of primary hairs at the skin surface (the highest density of primary hairs among bovids) likely forced larval ticks to traverse much of the body surface on top of the hair coat, making them vulnerable to being removed through licking and other grooming activity. Little grooming throughout late autumn and winter (November-March) corresponded to the period of coldest temperatures and snow on the ground, and was probably due to the bison's 'thermal inertia' strategy of energy conservation in which physical activity is minimized during the times of greatest cold stress, when forage is least available and of poorest quality. Newly born bison calves, 2 months old or younger, delivered 15-20 times more oral grooming per hour and 6 times more episodes per bout than did adult cows. This result is in accordance with the prediction of the body size principle of the programmed grooming hypothesis, which maintains that smaller animals should groom more frequently in order to maintain fewer ticks. Programmed grooming, which removes most larval ticks before they can attach, and the physical barrier of the dense hair coat, are proposed as the major reasons that bison host few D. albipictus.

Ingestion Rates and Aspects of Water, Sodium and Energy Metabolism in Caged Swamp Buffalo, Bubalus Bubalis, From Isotope Dilution and Materials Balances.

1982 ◽  
Vol 30 (5) ◽  
pp. 779 ◽  
Author(s):  
CK Williams ◽  
B Green
Keyword(s):  
Body Mass ◽  
Close Agreement ◽  
Bubalus Bubalis ◽  
The Body ◽  
High Rate ◽  
Evaporative Heat Loss ◽  
Northern Australia ◽  
Water Turnover ◽  
Daily Rate ◽  
Swamp Buffalo

Exchanges of DM, sodium, water and energy were estimated on caged swamp buffalo of body mass (W) 297 plus or minus 13 kg. Estimates of feed ingestion estimated from rates of 22Na and 3H turnover were in close agreement with estimates from weighing. Tritium equilibrated in 6 h and 22Na in 12 h. Tritium space was 78.9 plus or minus 1.6% of body mass at 6 h and 83.9 plus or minus 1.1% at 24 h. The body pool of exchangable Na was 40.56 plus or minus 1.79 mmol/kg W at 12 h, and 44.62 plus or minus 2.12 mmol/kg W at 24 h. The daily rate of water turnover was 34.72 plus or minus 2.33 litres or 326.1 plus or minus 17.2 ml/kg W0.82, about three times that expected on the basis of body size, reflecting adaptation to a tropical swamp habitat. It was due mainly to the high rate of imbibition, 30.78 plus or minus 2.15 litres daily or 289.1 plus or minus 16.3 ml/kg W0.82 daily. Daily rates of water loss were partitioned as: faecal, 9.99 plus or minus 0.761 (94.1 plus or minus 7.0 ml/kg W0.82); urinary, 10.39 plus or minus 0.76 litres (98.2 plus or minus 7.6 ml/kg W0.82); pulmocutaneous, 14.34 plus or minus 1.37 litres (133.8 plus or minus 8.9 ml/kg W0.82). Swamp buffalo are unlikely to be able to satisfy their water requirements from food alone during the dry season in northern Australia. The daily rate of Na turnover was 6.29 plus or minus 0.41 mmol/kg W0.75. Na in the faeces was low, 8.3 plus or minus 0.9 mmol/kg dry faeces, indicating very effective alimentary absorption of Na. Apparent digestible energy intake (DE) per day for maintenance was about 651 plus or minus 41 kJ/kg W0.75. Daily rates of evaporative heat loss were high, 481 plus or minus 33 kJ/kg W0.75, exceeding the non-evaporative component of the DE, 321 plus or minus 35 kJ/kg W0.75; evaporative processes may have contributed to the high maintenance DE.

The Physiology of the Antennal Gland of Carcinus Maenas (L.)

1969 ◽  
Vol 51 (1) ◽  
pp. 11-16
Author(s):  
R. BINNS
Keyword(s):  
Body Weight ◽  
Sea Water ◽  
Carcinus Maenas ◽  
Urine Flow ◽  
The Body ◽  
Antennal Gland ◽  
Urine Production ◽  
The Mean ◽  
Gland Function ◽  
Water Clearance

1. The space measured by inulin distribution, the ‘inulin volume’, has been determined, and represents approximately 20% of the body weight in crabs ranging in size from 20.0 to 57.2 g. 2. After the injection of labelled inulin into crabs, the increase in activity of the medium is equal to the fall in blood inulin in all dilutions of sea water. Clearance of inulin from the blood is due only to urine production, and therefore the molecule can be used for quantitative investigations of antennal gland function. 3. Urine production in various concentrations of sea water has been determined by measuring the clearance of inulin from the blood and the rates at which the tracer appeared in the external media. By these methods the mean rate of urine production in 100% sea water was estimated to be 4.4% body weight per day. In dilute sea water the rate of urine production increases; for example, in 50% sea water the urine flow is four times greater than in normal sea water.

Potassium metabolism and the accumulation of 137Caesium by decapod Crustacea

1962 ◽  
Vol 42 (2) ◽  
pp. 199-241 ◽  
Author(s):  
G. W. Bryan ◽  
Eileen Ward
Keyword(s):  
Body Surface ◽  
Soft Tissues ◽  
Sea Water ◽  
The Body ◽  
Limiting Factor ◽  
Freshwater Crayfish ◽  
Marine Animals ◽  
Decapod Crustacea ◽  
Concentration Factors ◽  
Potassium Metabolism

SUMMARYThe accumulation of 137Cs from sea water has been examined in relation to potassium metabolism in the lobster Homarus vulgaris and in the prawn Palaemon serratus. In unfed animals 137Cs is taken up and lost far more slowly than 42K. Although all the inactive K in the animals can be exchanged with 42K, higher whole-animal concentration factors are reached for 137Cs (about eight for lobsters and twenty-five for prawns). This is because both species have higher plasma/medium ratios for 137Cs than K at equilibrium despite the selective excretion of 137Cs. Also, except for the hepatopancreas in lobsters and fed prawns, all soft tissues can probably attain higher tissue/plasma ratios for 137Cs than inactive K.Uptake of both isotopes has also been studied in the freshwater crayfish Austropotamobius pallipes pallipes. In crayfish in o-i % sea water 137Cs is not concentrated to the same extent as K by whole animals (50-200 for 137Cs against about 4500 for K). Although the situation between plasma and tissues resembles that in the marine animals, 137Cs cannot be accumulated in the plasma to the same degree as K. Crayfish selectively excrete 137Cs in the urine relative to K at a lower concentration than in the plasma.In the accumulation of 137Cs by all species, muscle is the principal limiting factor in uptake and loss, but with 42K the body surface becomes more limiting.Experiments on the absorption of 137Cs from food in prawns and freshwater crayfish have been carried out. In prawns in a constant environment, feeding is probably less important than uptake over the body surface while in crayfish feeding is probably much more important.

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