Table 1.
Primer sequences designed for PCR, RACE-PCR and qPCR in this study.
Fig 1.
Molecular characterization of Na+/K+-ATPase α-subunit (Nkaα) isoforms of Electrophorus electricus.
A multiple amino acid alignment of Nkaα1c1, Nkaα1c2, Nkaα2 and Nkaα3 of E. electricus. Identical or strongly similar amino acids are indicated by shaded residues. The 10 predicted transmembrane regions (TM1–TM10) are underlined. Vertical boxes represent coordinating residues for Na+ or K+ binding. The conserved regions containing the TGES, DKTGTL, TGD and TGDGVND sequence motifs are double underlined. The hash marks denote the amino acid residues phosphorylated by PKA. The asterisks denote the amino acid residues phosphorylated by PKC. Substitution of amino acids is indicated by an arrow. The transmembrane domains of Nkaα1c1, Nkaα1c2, Nkaα2 and Nkaα3 of E. electricus were predicted using MEMSAT3 and MEMSAT-SVM provided by PSIPRED protein structure prediction server.
Table 2.
Percentage similarity between the amino acid sequences of Na+/K+-ATPase α1c1 (Nkaα1c1), Nkaα1c2, Nkaα2 and Nkaα3 from Electrophorus electricus and Nkaα sequences from other teleosts obtained from GenBank.
Fig 2.
A phenogramic analysis of Na+/K+-ATPase α-subunit (Nkaα) isoforms of Electrophorus electricus.
A phenogram illustrating the relationship among Nkaα1c1, Nkaα1c2, Nkaα2 and Nkaα3 of E. electricus and Nkaα isoforms of selected animals with Nkaα1 of Saccoglossus kowalevskii as the outgroup. The number at each branch represents the bootstrap value (max = 100).
Fig 3.
mRNA expression levels of Na+/K+-ATPase α1c1 (nkaα1c1) in Electrophorus electricus.
Absolute quantification (copies of transcript per ng of cDNA) of mRNA expression levels of nkaα1c1 in the skeletal muscle (SM), the main electric organ (EO), the Hunter’s EO and the Sach’s EO of (a) juvenile (N = 5) and (b) adult (N = 3) E. electricus kept in freshwater. Results represent mean + S.E.M. Means not sharing the same letter are significantly different (P<0.05).
Fig 4.
mRNA expression levels of Na+/K+-ATPase α1c2 (nkaα1c2) in Electrophorus electricus.
Absolute quantification (copies of transcript per ng of cDNA) of mRNA expression levels of nkaα1c2 in the skeletal muscle (SM), the main electric organ (EO), the Hunter’s EO and the Sach’s EO of (a) juvenile (N = 5) and (b) adult (N = 3) E. electricus kept in freshwater. Results represent mean + S.E.M. Means not sharing the same letter are significantly different (P<0.05).
Fig 5.
mRNA expression levels of Na+/K+-ATPase α2 (nkaα2) in Electrophorus electricus.
Absolute quantification (copies of transcript per ng of cDNA) of mRNA expression levels of nkaα2 in the skeletal muscle (SM), the main electric organ (EO), the Hunter’s EO and the Sach’s EO of (a) juvenile (N = 5) and (b) adult (N = 3) E. electricus kept in freshwater. Results represent mean + S.E.M. Means not sharing the same letter are significantly different (P<0.05).
Fig 6.
mRNA expression levels of Na+/K+-ATPase α3 (nkaα3) in Electrophorus electricus.
Absolute quantification (copies of transcript per ng of cDNA) of mRNA expression levels of nkaα3 in the skeletal muscle (SM), the main electric organ (EO), the Hunter’s EO and the Sach’s EO of (a) juvenile (N = 5) and (b) adult (N = 3) E. electricus kept in freshwater. Results represent mean + S.E.M. Means not sharing the same letter are significantly different (P<0.05).
Fig 7.
Western blotting results of Na+/K+-ATPase α-subunit (Nkaα) in juvenile Electrophorus electricus.
Protein abundance of Nkaα in the skeletal muscle (SM), the main electric organ (EO), the Hunter’s EO and the Sach’s EO of juvenile E. electricus kept in freshwater. (a) An example of the immunoblot of Nkaα. (b) The protein abundance of Nkaα expressed as arbitrary densitometric units per 100 μg protein. Results represent mean + S.E.M (N = 3). Means not sharing the same letter are significantly different among the SM and the three EOs (P<0.05).
Fig 8.
Western blotting results of Na+/K+-ATPase α-subunit (Nkaα) in adult Electrophorus electricus.
Protein abundance of Nkaα in the skeletal muscle (SM), the main electric organ (EO), the Hunter’s EO and the Sach’s EO of adult E. electricus kept in freshwater. (a) An example of the immunoblot of Nkaα. (b) The protein abundance of Nkaα expressed as arbitrary densitometric units per 20 μg protein. Results represent mean + S.E.M (N = 3). Means not sharing the same letter are significantly different among the three EOs (P<0.05). Nkaα was not detectable (n.d.) in the SM.
Table 3.
Vmax (μmol Pi released·min-1·g-1 tissue; N = 4) and Km (mmol l-1; N = 4) values of Na+/K+-ATPase (Nka) from the main electric organ (EO), the Hunter’s EO and the Sach’s EO of juvenile Electrophorus electricus.