Ceratotoxin: antimicrobial activity of the peptide and expression of the gene

In the medfly Ceratitis capitata the female accessory glands secrete a fluid containing several proteins, most of them of low molecular weight. Such fluid was found to have antimicrobial properties, including lysozyme activity. Two closely related 3 kDa peptides, named ceratotoxins A and B, effective against E. coli K12, were purified from the secretion. Synthetic ceratotoxin A was tested and demonstrated effective against several Gram-negative and -positive bacterial strains. The cDNA sequence encoding ceratotoxin A was determined. Ceratotoxin gene resulted to be sex-specific and expressed exclusively in the accessory glands of the female adult of Ceratitis capitata.