An aquatic vertebrate can use amino acids from environmental water.
Conventional food-web theory assumes that nutrients from dissolved organic matter are transferred to aquatic vertebrates via long nutrient pathways involving multiple eukaryotic species as intermediary nutrient transporters. Here, using larvae of the salamander Hynobius retardatus as a model system, we provide experimental evidence of a shortcut nutrient pathway by showing that H. retardatus larvae can use dissolved amino acids for their growth without eukaryotic mediation. First, to explore which amino acids can promote larval growth, we kept individual salamander larvae in one of eight different high-concentration amino acid solutions, or in control water from which all other eukaryotic organisms had been removed. We thus identified five amino acids (lysine, threonine, serine, phenylalanine, and tyrosine) as having the potential to promote larval growth. Next, using15N-labelled amino acid solutions, we demonstrated that nitrogen from dissolved amino acids was found in larval tissues. These results suggest that salamander larvae can take up dissolved amino acids from environmental water to use as an energy source or a growth-promoting factor. Thus, aquatic vertebrates as well as aquatic invertebrates may be able to use dissolved organic matter as a nutrient source.
Teshio Experimental Forest, Field Science Center for Northern Biosphere, Hokkaido University, Toikanbetsu, Horonobe, Hokkaido 098-2943, Japan Tomakomai Experimental Forest, Field Science Center for Northern Biosphere, Hokkaido University, Takaoka, Tomakomai, Hokkaido 053-0035, Japan noborukata1913@gmail.com.
Noboru
http://orcid.org/0000-0003-1602-7497
N
Katayama
Teshio Experimental Forest, Field Science Center for Northern Biosphere, Hokkaido University, Toikanbetsu, Horonobe, Hokkaido 098-2943, Japan.
Kobayashi
K
Makoto
Teshio Experimental Forest, Field Science Center for Northern Biosphere, Hokkaido University, Toikanbetsu, Horonobe, Hokkaido 098-2943, Japan Tomakomai Experimental Forest, Field Science Center for Northern Biosphere, Hokkaido University, Takaoka, Tomakomai, Hokkaido 053-0035, Japan.
Osamu
O
Kishida
Hynobius retardatus; aquatic animal; dissolved organic nitrogen uptake; growth rate; nutrient flow; stable isotope
J Comp Physiol B. 2013 Oct;183(7):877-91
23660826
Proc Biol Sci. 2011 Oct 22;278(1721):3096-101
21367787
J Pharmacol Exp Ther. 1993 Oct;267(1):364-70
8229763
Biochim Biophys Acta. 1988 Feb 24;947(1):113-38
3278737
J Int Soc Sports Nutr. 2004 Dec 31;1(2):7-11
18500949
Proc Natl Acad Sci U S A. 2009 Mar 17;106(11):4301-6
19251645
Science. 1983 Apr 8;220(4593):204-6
17795831
Physiol Biochem Zool. 2011 Nov-Dec;84(6):607-17
22030853
J Exp Biol. 2008 Mar;211(Pt 6):860-5
18310111
Proc Biol Sci. 2016 Sep 28;283(1839):
27683364
Acta Physiol Scand. 2000 Jan;168(1):1-17
10691773
Springerplus. 2015 Mar 27;4:147
25830085
Ecology. 2015 Jul;96(7):1887-98
26378311
Integr Comp Biol. 2006 Oct;46(5):634-42
21672774
J Exp Biol. 2005 May;208(Pt 9):1621-5
15855393
Nat Methods. 2012 Jul;9(7):671-5
22930834
Proc Natl Acad Sci U S A. 2013 Feb 26;110(9):3229-36
23391737
Amino Acids. 2009 May;37(1):43-53
18751871
Biol Bull. 2009 Aug;217(1):6-24
19679719