Nitrogen excretion in developing zebrafish (Danio rerio): a role for Rh proteins and urea transporters

Abstract

Braun MH, Steele SL, Ekker M, Perry SF. Nitrogen excretion in developing zebrafish (Danio rerio): a role for Rh proteins and urea transporters.

Ammonia excretion in the freshwater planarianSchmidtea mediterranea

“…Rates for developing zebrafish larvae (9days post fertilization) are ca. 2molg -1 FMh -1 (Braun et al, 2009). Immediately after feeding, ammonia excretion rates roughly quadrupled compared with controls ( Fig.1), an increase in metabolic ammonia production similar to that observed in the green shore crab, C. maenas (Weihrauch, 1999), but much higher than values in rainbow trout (Zimmer et al, 2010), where excretion rates increase not directly after food intake but after a delay of approximately 2 to 4h.…”

The involvement of SLC26 anion transporters in chloride uptake in zebrafish (Danio rerio) larvae

“…Indeed, we are unaware of any isotope provider currently able to supply 36 Cl to North American researchers. The previous evidence implicating Cl -/HCO 3 -exchange as a mechanism for Cl -uptake in freshwater fish is overwhelming (Krogh, 1937;Krogh, 1938;Maetz and Garcia Romeu, 1964;De Renzis and Maetz, 1973;De Renzis, 1975;Braun et al, 2009) (reviewed by Marshall, 1995;Claiborne, 1998;Evans et al, 1999;Marshall, 2002;Perry et al, 2003a;Perry et al, 2003b;Evans et al, 2005;Perry and Gilmour, 2006;Marshall and Grosell, 2006;Tresguerres et al, 2006;Hwang and Lee, 2007;Evans, 2008). Prior to the demonstration of pendrin (SLC26A4)-like immunoreactivity on the elasmobranch gill (Piermarini et al, 2001), it was generally considered that branchial Cl -/HCO 3 -exchange was accomplished by one or more members of the SLC4 gene family.…”

An animal homolog of plant Mep/Amt transporters promotes ammonia excretion by the anal papillae of the disease vector mosquito,Aedes aegypti

“…In larvae of freshwater zebrafish, an Rh50 protein, Rhcg1, is required along with VA to actively excrete ammonia against a higher external concentration (Shih et al, 2013). The transcript abundance of Rhcg1 and VA increases with exposure to high environmental ammonia (HEA) and the capacity for ammonia excretion by ammonia-excreting cells increases (Braun et al, 2009). HEA exposure of the fully aquatic, freshwaterinhabiting African clawed frog caused a decrease in the transcript levels of Rhbg, VA and NKA in the dorsal and ventral skin and reduced the capacity of the skin to excrete ammonia (Cruz et al, 2013).…”

“…Members of the methylammonium permease/ammonium transporter (Mep/Amt) family of transporters play a critical role in ammonia uptake by plants and microorganisms (Thornton et al, 2006;Nygaard et al, 2006;Willmann et al, 2007;Gu et al, 2013;Wu et al, 2015). The annotated genomes of vertebrate animals lack Mep/Amt homologs and excretion of ammonia in animals has been linked to members of a related family of glycoproteins, the Rhesus glycoproteins (RhGPs) (Nawata et al, 2007;Braun et al, 2009;Shih et al, 2013). Interestingly, homologs of the Mep/Amt transporters are present in the invertebrates along with homologs of RhGPs (Weihrauch et al, 2012b; Fig.…”

“…Through work on frog skin, planarians, and crustacean and fish gills, a number of cellular mechanisms and transporters for ammonia excretion in freshwater animals have been discovered. In addition to the RhGPs and the Mep/Amts, these include members of the solute carrier family 9 (SLC9, NHEs) (Orlowski and Grinstein, 2004;Zachos et al, 2005); the Na + /K + -ATPase (NKA) (Masui et al, 2002;Furriel et al, 2004;Weihrauch et al, 2012b;Ip et al, 2012); and the V-type H + -ATPase (VA) (Wilson et al, 1994;Shih et al, 2008;Braun et al, 2009;Weihrauch et al, 2009;Wright and Wood, 2009).…”