scholarly journals Variations in the Osmotic Concentration of the Blood and Coelomic Fluids of Aquatic Animals, caused by Changes in the External Medium

1908 ◽  
Vol 3 (10) ◽  
pp. 473-490 ◽  
Author(s):  
W. J. Dakin
1977 ◽  
Vol 66 (1) ◽  
pp. 97-110
Author(s):  
T. J. Bradley ◽  
J. E. Phillips

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.


1977 ◽  
Vol 66 (1) ◽  
pp. 83-96 ◽  
Author(s):  
T. J. Bradley ◽  
J. E. Philips

1. Larvae of the saline-water mosquito Aedes campestris were adapted to three waters, all having an osmotic concentration of 700 mOsm, but differing in ionic rations. The (Na+Mg) SO4 medium was much moretoxic than the NAHCO3 or the NaCl media. 2. Ionic and osmotic concentrations of haemolymph and rectal secretion were measured in larvae adapted to all three media. The ratio of ionic concentrations in the rectal secretion reflected those in the external medium to which the larvae had been adapted, with the exception of SO42-, which was possibly replaced by HCO3-in the secretion. These differences in rectal fluid composition persisted even though all ligated recta were bathed in the same artificial haemolymph. 3. The Malpighian tubules were found to be the major site of SO42- excretion. In media containing high levels of NA+, Mg2+, K+, Cl- and HCO3-, the rectum secreted a hyperosmotic fluid containing these ions at concentrations several times greater than those found in the haemolymph. 4. These data provide the basis for speculation on the functioning of anal papillae in waters of diverse chemical composition.


1941 ◽  
Vol 18 (2) ◽  
pp. 110-114
Author(s):  
N. KESAVA PANIKKAR

The blood of Chirocephalus has a normal osmotic concentration equivalent to 0.44-0.5% NaCl in an external medium of 0.002% NaCl. The osmotic pressure falls rapidly when the animal is kept in glass-distilled water, but is fairly well maintained in tap water. There is an initial rise and a later return to normal even in hypotonic saline media, and this indicates active absorption of ions. The bracts are presumably the organs concerned in the salt absorption. The animal is unable to live in tap water or distilled water for more than 2-3 days without food and its general behaviour is thus markedly different from that of Daphnia.


1984 ◽  
Vol 35 (4) ◽  
pp. 483 ◽  
Author(s):  
NN Tait ◽  
D Atapattu ◽  
R Browne

Although G. caespitosa is able to survive seawater dilution down to 60% seawater, oocytes released into 60% seawater are not viable. Despite this, a greater percentage of oocytes released into 60% seawater are induced to undergo prematuration (as indicated by the initiation of meiosis) than occurs in oocytes released into normal seawater. Unspawned oocytes in adult worms maintained in 60% seawater are protected from this osmotic shock despite equilibration of the osmotic concentration of the body fluids with the external medium.


Author(s):  
Martin Hagopian ◽  
Michael D. Gershon ◽  
Eladio A. Nunez

The ability of cardiac tissues to take up norepinephrine from an external medium is well known. Two mechanisms, called Uptake and Uptake respectively by Iversen have been differentiated. Uptake is a high affinity system associated with adrenergic neuronal elements. Uptake is a low affinity system, with a higher maximum rate than that of Uptake. Uptake has been associated with extraneuronal tissues such as cardiac muscle, fibroblasts or vascular smooth muscle. At low perfusion concentrations of norepinephrine most of the amine taken up by Uptake is metabolized. In order to study the localization of sites of norepinephrine storage following its uptake in the active bat heart, tritiated norepinephrine (2.5 mCi; 0.064 mg) was given intravenously to 2 bats. Monoamine oxidase had been inhibited with pheniprazine (10 mg/kg) one hour previously to decrease metabolism of norepinephrine.


2021 ◽  
Vol 7 (14) ◽  
pp. eabg0677
Author(s):  
Becca Franks ◽  
Christopher Ewell ◽  
Jennifer Jacquet

The unprecedented growth of aquaculture involves well-documented environmental and public-health costs, but less is understood about global animal welfare risks. Integrating data from multiple sources, we estimated the taxonomic diversity of farmed aquatic animals, the number of individuals killed annually, and the species-specific welfare knowledge (absence of which indicates extreme risk). In 2018, FAO reported 82.12 million metric tons of farmed aquatic animals from six phyla and at least 408 species—20 times the number of species of farmed terrestrial animals. The farmed aquatic animal tonnage represents 250 to 408 billion individuals, of which 59 to 129 billion are vertebrates (e.g., carps, salmonids). Specialized welfare information was available for 84 species, only 30% of individuals; the remaining 70% either had no welfare publications or were of an unknown species. With aquaculture growth outpacing welfare knowledge, immediate efforts are needed to safeguard the welfare of high-production, understudied species and to create policies that minimize welfare risks.


Sign in / Sign up

Export Citation Format

Share Document