Analysis of the B-Type Natriuretic Peptide and the Aminoterminal-Pro-B-Type Natriuretic Peptide in Different Parrot, Raptor and Owl Species

Abstract

The B-type natriuretic peptide (BNP), a member of the natriuretic peptide family and a cardiac hormone, is produced mainly in the ventricular myocytes and released into the circulation due to mechanical stimuli during an increasing cardiac wall stretch. BNP has a significant role in the regulation of the cardiovascular system and body fluid. The concentration of this hormone and of the biologically inactive amino-terminal-prohormone in the blood plasma is a helpful diagnostic tool for detecting cardiovascular diseases in human medicine and can be used as a prognostic marker for the risk of mortality, whilst such a tool does not exist for avian medicine. To date, the amino acid sequence of BNP is not known for many of the species commonly presented in avian consultation. In this study, the amino acid sequence of BNP and the prepropeptide was described for 12 parrot species as well as 3 raptor and 3 owl species by polymerase chain reaction (PCR) after RNA isolation from the heart. The results showed a high similarity between the amino acid sequences in the mature peptide region of the BNP. The prepropeptide showed several differences between the examined species, some of them shared by closely related species.

Keywords: brain natriuretic peptide; cardiovascular diseases; heart; owls; parrots; raptors.

Figure 1

The PCR products of a grey parrot (a), a scarlet macaw (b) and a cockatiel (c) aligned with the marker (M) on the GelRed^®-stained 2% agarose gel after gel electrophoresis (base pairs, bp).

Figure 2

Nucleotide sequences of the mature peptide region of the BNP of the examined species aligned with the sequences of the pigeon and grey parrots, all consisting of 90 nucleotides. The stop codon is shown in brackets. The nucleotides that differ from the majority of the examined species are shaded in blue. Aberrations between animals of the same species as they were found in a previous study are shaded in green [21].

Figure 3

The amino acid sequences of the BNP prepropeptide of the species examined in this study. The 17-amino-acid ring structure is in bold letters and underlined. The asterisk marks a stop codon. The amino acids that differ from the majority of the examined species are shaded in blue.

Figure 4

The amino acid sequence of the BNP prepropeptide of pigeons and chickens, as already known from previous studies. The signal peptide sequence is underlined, and the mature peptide region is shown in bold letters. The 17-amino-acid ring structure is in bold letters and underlined. The asterisk marks a stop codon. The amino acids that differ from the majority of the examined species are shaded in blue. GenBank accession numbers: NM_204925.1 Gallus gallus natriuretic peptide A (NPPA); NM_001282844.1 Columba livia natriuretic peptides A-like (BNP); AY398687.1 Crocodylus porosus B-type natriuretic peptide; AY433953.1 Chelodina longicollis B-type natriuretic peptide (BNP).

Figure 5

A phylogenetic tree of the examined species aligned with chicken, tortoise and crocodile sequences, based on the prepropeptide amino acid sequences from Figure 3 and Figure 4. The genetic distance in substitutions per position is shown below.