Potential of active excretion of ammonia in three different haline species of crabs

Aedes aegypti Rhesus glycoproteins contribute to ammonia excretion by larval anal papillae

“…Furthermore, the levels of ammonia in the hemolymph of insects in comparison to other animals demonstrate their increased tolerance to this toxic molecule (see Weihrauch et al, 2012b). For example, Drosophila melanogaster larvae feed and develop in media containing up to 30 mmol l −1 ammonia (Borash et al, 1998), and the ammonia hemolymph levels of black flies (5 mmol l −1 ; Gordon and Bailey, 1974), Manduca sexta larvae (0.8 mmol l −1 ; Weihrauch, 2006) and larval A. aegypti (up to ∼1.5 mmol l −1 ; Chasiotis et al, 2016) are much higher than those of aquatic crabs (Weihrauch et al, 1999) and mammals (Cooper and Plum, 1987), where levels are no greater than 400 μmol l −1 (see Weihrauch et al, 2004). Environmental ammonia levels as low as 19 μmol l −1 NH 3 are lethal to crustaceans (Ostrensky et al, 1992), but remarkably, A. aegypti larvae exposed to 1 mmol l −1 NH 4 Cl for 3 days not only survive, but also quickly adjust to the HEA conditions by increasing NH 4 + and H + excretion from the anal papillae (Weihrauch et al, 2012b).…”

Freshwater Decapods and Pesticides: An Unavoidable Relation in the Modern World

“…The high lipid solubility of ammonia makes it more diffusible through phospholipid bilayers. The mechanism supporting ammonia excretion in crustaceans is the simple diffusion of the non-ionic NH 3 along a concentration gradient and the partial excretion of the ionised form NH 4 + , whose release through diffusion is facilitated because of its hydrophobicity (Weihrauch et al, 1999(Weihrauch et al, , 2004. Several aquatic crab species possess an excretion system based on the ionised form of ammonia, NH 4 + , a water soluble compound which effluxes through the gill epithelium.…”

“…Freshwater crabs have tighter gill epithelia than their marine relatives, developed to avoid ionic efflux and tolerate a hyposmotic environment. This epithelium is much less permeable by NH 4 + , and freshwater crabs release their nitrogen compounds mainly as ammonia (Weihrauch et al, 1999).…”

“…Ammonia toxicity is mediated by the excessive activation of N-methyl-D-aspartate (NMDA)-type glutamate receptors in the brain. As a consequence, cerebral ATP is depleted, while intracellular Ca 2+ increases, with subsequent increases in intracellular K + and, finally, cell death (Weihrauch et al, 1999(Weihrauch et al, , 2004. The intensity of the observed effects is related to pesticide concentration and animal resistance.…”

Ammonia excretion inCaenorhabditis elegans: mechanism and evidence of ammonia transport of the Rhesus protein CeRhr-1

“…For the basolateral localized Na + /K + -ATPase, it was shown in 1960 by Jens Skou that this enzyme does accept NH 4 + as a substrate by replacing K + ions (Skou, 1960) and thereby is capable of actively pumping NH 4 + from the body fluids into the respective ammonia-transporting epithelial cell. The direct participation of this pump in the ammonia transport mechanism has now been identified for numerous systems, including those in gills of crustaceans (Furriel et al, 2004;Masui et al, 2002;Weihrauch et al, 1998;Weihrauch et al, 1999) and fish (Mallery, 1983;Nawata et al, 2010a;Wood et al, 2013), frog skin (Cruz et al, 2013), mammalian kidney (Garvin et al, 1985;Wall and Koger, 1994) and intestine (Worrell et al, 2008). The second pump often, if not always, involved in the ammonia transport processes is the V-ATPase.…”