Discovery and Characterization of Two Isoforms of Moronecidin, a Novel Antimicrobial Peptide from Hybrid Striped Bass

Abstract

We isolated a novel 22-residue, C-terminally amidated antimicrobial peptide, moronecidin, from the skin and gill of hybrid striped bass. Two isoforms, differing by only one amino acid, are derived from each parental species, white bass (Morone chrysops) and striped bass (Morone saxatilis). Molecular masses (2543 and 2571 Da), amino acid sequences (FFHHIFRGIVHVGKTIH(K/R) LVTGT), cDNA, and genomic DNA sequences were determined for each isoform. A predicted 79-residue moronecidin prepropeptide consists of three domains: a signal peptide (22 amino acids), a mature peptide (22 amino acids), and a C-terminal prodomain (35 amino acids). The synthetic, amidated white bass moronecidin exhibited broad spectrum antimicrobial activity that was retained at high salt concentration. An ␣-helical structure was confirmed by circular dichroism spectroscopy. The moronecidin gene consists of three introns and four exons. Peptide sequence and gene organization were similar to pleurocidin, an antimicrobial peptide from winter flounder. A TATA box and several consensus-binding motifs for transcription factors were found in the region 5 to the transcriptional start site. Moronecidin gene expression was detected in gill, skin, intestine, spleen, anterior kidney, and blood cells by kinetic reverse transcription (RT)-PCR. Thus, moronecidin is a new ␣-helical, broad spectrum antimicrobial peptide isolated from the skin and gills of hybrid striped bass.

Antibacterial and Antifungal Activities of Proteins Extracted from Seven Different Snails

“…The minimum inhibitory concentration (MIC) was determined by the micro dilution method [20] by using liquid nutrient broth with different concentrations of proteins from seven different snails. A total of 3.6 mL of sterilized nutrient broth was poured into a sterilized test tube.…”

“…The plates were incubated at 37 °C for 24 h. The diameters of the zone of inhibition were measured in millimeter by using the antibiotic zone measuring scale. The minimum inhibitory concentration (MIC) was determined by the micro dilution method [20] by using liquid nutrient broth with different concentrations of proteins from seven different snails. A total of 3.6 mL of sterilized nutrient broth was poured into a sterilized test tube.…”

Discovery and characterization of two types of liver-expressed antimicrobial peptide 2 (LEAP-2) genes in rainbow trout

“…To date several AMPs have been discovered in bony fish, primarily from the skin and mucous glands of several species of flatfish species, the loach and the hybrid striped bass (Cole et al, 1997;Lauth et al, 2002;Zhou et al, 2002). An exception is LEAP-1 (hepcidin), which has been reported recently in many species including salmonids (rainbow trout and Atlantic salmon, Salmo salar) Patrzykat and .…”

NK-lysin of channel catfish: Gene triplication, sequence variation, and expression analysis

“…Over 800 AMP sequences have been deposited in the Antimicrobial Peptide Database (http://bbcm1.univ.trieste.it/∼tossi/pag1.htm). Increasing numbers of antimicrobial peptides have been identified from teleost fishes in recent years (e.g., Cole et al, 1997;Douglas et al, 2001Douglas et al, , 2003aLauth et al, 2002;Shike et al, 2002Shike et al, , 2004Noga and Silphaduang, 2003;Zhang et al, 2004;Bao et al, 2005, in press;Xu et al, 2005). As the largest vertebrate group containing over 23,000 species (Helfman et al, 1997), teleosts should be a rich source of antimicrobial peptides.…”