Methyl–hydride metathesis between [Zr(cp)2Me2] and [HAl(μ3-NBut)]4: molecular structures of [Me1−xHxAl(μ 3-NBut)]4 (x = 0, 0.78 or 1) and [(cp)2ZrMe(μ-H)]2 (cp = η5-C5H5)

<p>Absolute quantification (copies of transcript per ng of cDNA) of <i>scn2b</i> transcripts in the main EO, the Hunter’s EO, the Sach’s EO and the SM of (a) adult or (b) juvenile <i>E</i>. <i>electricus</i> kept in fresh water. Results represent means ± S.E.M. (<i>N</i> = 4). Means not sharing the same letter are significantly different (<i>P</i><0.05).</p

mRNA expression levels of the <i>voltage-gated Na</i>^<i>+</i> <i>channel type IV α-subunit a isoform</i> (<i>scn4aa</i>) in the electric organs (EOs) and the skeletal muscle (SM) of <i>Electrophorus electricus</i>.

<p>Absolute quantification (×10³ copies of transcript per ng of cDNA) of <i>scn4aa</i> transcripts in the main EO, the Hunter’s EO, the Sach’s EO and the SM of (a) adult or (b) juvenile <i>E</i>. <i>electricus</i> kept in fresh water. Results represent means ± S.E.M. (<i>N</i> = 4). Means not sharing the same letter are significantly different (<i>P</i><0.05).</p

Protein abundances of voltage-gated Na⁺ channel β-subunit 4 isoform (Scn4b) in the electric organs (EOs) and the skeletal muscle (SM) of <i>Electrophorus electricus</i>.

<p>Representative immunoblots and protein abundances of Scn4b in the main EO, the Hunter’s EO, the Sach’s EO and the SM of (a) adult or (b) juvenile <i>E</i>. <i>electricus</i>. Protein abundance is expressed as arbitrary densitometric units per 20 μg protein. Results represent mean ± S.E.M (<i>N</i> = 3). Means not sharing the same letter are significantly different (<i>P</i> < 0.05).</p

Percentage similarity between the amino acid sequence of voltage-gated Na⁺ channel (Scn) β-subunit isoforms (Scn1b, Scn2b and Scn4b) of <i>Electrophorus electricus</i> in comparison with Scnb/SCNB of other animal species obtained from GenBank.

<p>Sequences are arranged in descending order of similarity. Similarity indices were obtained using the BioEdit software.</p

mRNA expression levels of the <i>voltage-gated Na</i>^<i>+</i> <i>channel β-subunit 1 isoform</i> (<i>scn1b</i>) in the electric organs (EOs) and the skeletal muscle (SM) <i>Electrophorus electricus</i>.

<p>Absolute quantification (copies of transcript per ng of cDNA) of <i>scn1b</i> transcripts in the main EO, the Hunter’s EO, the Sach’s EO and the SM of (a) adult or (b) juvenile <i>E</i>. <i>electricus</i> kept in fresh water. Results represent means ± S.E.M. (<i>N</i> = 4). Means not sharing the same letter are significantly different (<i>P</i><0.05).</p

Protein abundances of voltage-gated Na⁺ channel type IV α-subunit b isoform (Scn4ab) in the electric organs (EOs) and the skeletal muscle (SM) of <i>Electrophorus electricus</i>.

<p>Representative immunoblots and protein abundances of Scn4ab in the main EO, the Hunter’s EO, the Sach’s EO and the SM of (a) adult or (b) juvenile <i>E</i>. <i>electricus</i>. Protein abundance is expressed as arbitrary densitometric units per 20 μg protein. Results represent mean ± S.E.M (<i>N</i> = 3). Means not sharing the same letter are significantly different (<i>P</i> < 0.05).</p

Percentage similarity between the amino acid sequence of voltage-gated Na⁺ channel (Scn) type IV α-subunit isoforms (Scn4aa and Scn4ab) of <i>Electrophorus electricus</i> as compared with Scn4aa and Scn4ab of other teleosts obtained from GenBank.

<p>Sequences are arranged in descending order of similarity. Similarity indices were obtained using the BioEdit software.</p

Effects of light on the mRNA expression level and protein abundance of <i>Na</i>⁺<i>/Ca</i>^<i>2+</i> <i>exchanger/</i> Na⁺/Ca²⁺ exchanger <i>(NCX</i>/NCX<i>)</i> in the inner mantle of <i>Tridacna squamosa</i>.

<p>(A) The transcript level (x 10³ copies of transcripts per ng total RNA) of <i>NCX</i> transcripts in the inner mantle of <i>T</i>. <i>squamosa</i> exposed to 12 h of darkness (control) or 3, 6 or 12 h of light. Results represent means + S.E.M (<i>N</i> = 4). Means not sharing the same letter are significantly different from each other (<i>P</i><0.05). (B) The intensity of the NCX band for 50 μg protein was normalized with respect to that of tubulin. Results represent means + S.E.M (<i>N</i> = 4). Means not sharing the same letter are significantly different (<i>P</i><0.05).</p

Validation of immunofluorescence of Na⁺/K⁺-ATPase α (NKAα) labelling of the inner mantle of <i>Tridacna squamosa</i> by a peptide competition assay (PCA).

<p>Immunofluorescent localization of NKAα in the inner mantle (IM) of <i>T</i>. <i>squamosa</i> exposed to 12 h of light using the custom-made anti-NKAα antibody (A, C), or anti- NKAα antibody pre-incubated with the immunizing peptide in PCA (B, D). Green represents anti-NKAα immunofluorescence. The nuclei are counterstained with DAPI in blue. Together, the green and blue channels are merged and overlaid with differential interference contrast images (DIC). Arrowheads in (A, C) show basolateral staining of NKAα on the epithelium (EP) facing the extrapallial fluid (EPF) compared to the lack of NKAα staining in the control with PCA (b, d). SW, seawater. Scale bar: 20μm.</p

Analyses of Na⁺ and K⁺ binding sites of Na⁺/K⁺-ATPase α (NKAα).

<p>A multiple amino acid sequence alignment of a region of NKAα from the inner mantle of <i>Tridacna squamosa</i>, with Nkaα1a (JN180940), Nkaα1b (JN180941), and Nkaα1c (JN180942) from the gills of <i>Anabas testudineus</i>. Identical amino acid residues are indicated by shaded black residues and similar amino acids (threshold value 50%) are indicated by shaded gray residues. Vertical boxes represent coordinating residues for Na⁺ or K⁺ binding. Asterisks indicate the amino acid residue that is similar to Nkaα1c but different from Nkaα1a and Nkaα1b.</p