... is concentration dependent (1–1000 mmol l −1 , Michaelis–Menten-like kinetics; K ½ =127, 173 and 345 mmol l −1 ), and values at [urea]=1 mmol l −1 are 29.5×10 −6 , 467×10 −6 and 260×10 −6 cm s −1 , respectively. Diffusional water permeability, P d , was 0.84×10 −3 (chick), 5.95×10 −3 (duck), 0.39×10 −3 ( Amphiuma...

... © The Company of Biologists Limited 2006 2006 crab Hemigrapsus osmoregulation excretion development water permeability sodium transport embryonic dorsal organ silver staining Hemigrapsus sexdentatus (formerly H. edwardsii ) and H. crenulatus are euryhaline intertidal...

... of the fluid segregation and membrane dynamics that govern fluid discharge cycles in the contractile vacuole complex. The membrane vesicles shrank when the external osmolarity was increased,and swelled when the osmolarity was decreased, implying that the contractile vacuole complex membrane is water permeable...

... loss CO 2 output water permeability tritiated water 14 CO 2 Several methods have been used to study water loss of insects in air. Most studies have been made by gravimetric methods, in which loss of mass in dry air has been followed. An early example is the classic study of Ramsay (1935...

...-Nesbitt, 1989 ; Noble-Nesbitt, 1991 ), values as low as these are difficult to explain in terms of the water diffusion properties of liquid oil or solid wax. There is no obvious relationship between water permeability and initial mass of the insect ( Fig. 2A ). However, there is an interesting...

...Peter J. Campbell; M. B. Jones ABSTRACT Water permeability [based on the half-time of exchange of body water with the environment ( T 1/2 )] of the upper estuarine prawn Palaemon longirostris was measured in a range of salinities at 4, 12 and 20°C. Prawns acclimated for 7 days were compared...

...P. C. Croghan; J. Noble-Nesbitt 20 11 1989 © 1990 by Company of Biologists 1990 control of permeability insect cuticle water permeability In a recent note ( Croghan and Noble-Nesbitt, 1989 ), it was shown that water permeability of the cockroach epicuticle could...

... them. 6 12 1989 © 1989 by Company of Biologists 189 diffusion of water insect cuticle water permeability It seems, therefore, that it would be useful to derive, rigorously, simple relationships between the parameters involved in the diffusion of water across oil and wax...

... calculations demonstrated the need for knowledge of the water permeability of the membranes of epithelial cells for the purpose of estimation of the osmotic gradients required for fluid absorption. We measured the hydraulic water permeability of the individual cell membranes of Necturus gallbladder...