...Michael A. Menze; Nadja Hellmann; Heinz Decker; Manfred K. Grieshaber ABSTRACT Haemocyanin serves as an oxygen carrier in the haemolymph of decapod crustaceans. The oxygen-binding behaviour of the pigment is modulated by the two major anaerobic metabolites, L-lactate and urate. The binding...

... μmol l −1 the pH-dependence of P 50 remained unchanged. The potentiating effect of dopamine could be quantified as Δlog P 50 / Δlog[dopamine]=−0.10, which is similar to values for lactate and urate (see above), but at much lower concentrations of 10 −9 –10 −3 mol l −1 compared with 10 −4 –10 −2...

...) of the hydrothermal vent tubeworm Riftia pachyptila to acquire a general overview of nitrogen metabolism in this symbiotic organism. There were striking differences between the symbiont-containing trophosome tissue and other host tissues. High concentrations of ammonia, creatinine and, in particular, urate were found...

... reimmersion. Muscle and hepatopancreas urate contents and haemolymph serum protein levels were also measured during emersion. In air-exposed C. maenas , the muscle FAA pool increased significantly within the first 24 h of emersion. This increase was due to an increase in the non-essential amino acid (NEAA...

...Fabrice Durand; Michèle Regnault ABSTRACT Carcinus maenas and Necora puber were exposed to air for 72 h and 18 h, respectively, at 18 °C. Nitrogen excretion, blood and muscle ammonia content and blood urate and lactate content were recorded throughout the experimental emersion and following...

...Stuart M. Linton; Peter Greenaway ABSTRACT The urate content of the gecarcinid land crab Gecarcoidea natalis was correlated to the amount of nitrogen assimilated. Crabs fed a high-nitrogen diet ( ad libitum amounts of soy beans and fig leaves, Ficus macrophylla ) for 6 weeks assimilated...

...A. Nies; B. Zeis; C. R. Bridges; M. K. Grieshaber ABSTRACT The haemocyanin of Homarus vulgaris possesses specific binding sites for L-lactate and urate, two allosteric modulators of haemocyanin oxygen-affinity. The affinities for both ligands have been determined. The dissociation constants, K D...

...B. Zeis; A. Nies; C. R. Bridges; M. K. Grieshaber ABSTRACT The specific effects of L-lactate and urate on oxygen binding by the haemo-cyanin of the lobster Homarus vulgaris were investigated. Increasing concentrations of L-lactate were found to increase haemocyanin oxygen-affinity. The relationship...

... and urate to total buffering capacity of tubular fluid was estimated to be 75°, with bicarbonate responsible for 55° of the total. 6. The maximum rate of acid removal by all Malpighian tubules of starved locusts, including H + trapped in ammonium ions, was calculated to be very small in relation to the acid...

... in haemocyanin oxygen-affinity induced by metabolic acidosis via the Bohr shift was substantially balanced by the opposing effect of L-lactate ( Booth et al . 1982 ). Since this study, Morris et al . (1985) have discovered that urate also enhances haemocyanin oxygen-affinity in the crayfish Austropotamobius...

...F. Lallier; J. P. Truchot ABSTRACT The addition of either L-lactate or urate to dialysed haemolymph from the prawn Penaeus japonicus (Bate) increased the in vitro haemocyanin oxygen affinity. The quantitative values of these two effects, expressed as ΔlogP 50 / Δlog[effector], were found to be −0...