1. Presence of antibacterial peptides on the laid egg chorion of the medfly Ceratitis capitata
D Marchini, L Marri, M Rosetto, A G Manetti, R Dallai Biochem Biophys Res Commun. 1997 Nov 26;240(3):657-63. doi: 10.1006/bbrc.1997.7694.
Female reproductive accessory glands of the medfly Ceratitis capitata produce a secretion with antibacterial activity mainly ascribed to ceratotoxin peptides. To study whether the secretion from the accessory glands of the female protects the eggs and early larva from microbes, we examined whether ceratotoxins and other accessory gland components could be found on the egg surface. This was found to be the case; a water-soluble material with the same protein and antibacterial pattern as that of the accessory gland secretion was recovered from the laid egg surface and was observed as electrondense, clustered droplets over the outer exochorion. Such material showed the same electrophoretic pattern in both mated and virgin females. These findings indicate that the accessory gland secretion is spread, at oviposition, onto the eggs producing an antibacterial coating, irrespective of fertilization. This is the first report of antimicrobial components recovered from a material layered on insect laid eggs.
2. Molecular characterization of ceratotoxin C, a novel antibacterial female-specific peptide of the ceratotoxin family from the medfly Ceratitis capitata
M Rosetto, A G Manetti, P C Giordano, L Marri, R Amons, C T Baldari, D Marchini, R Dallai Eur J Biochem. 1996 Oct 15;241(2):330-7. doi: 10.1111/j.1432-1033.1996.00330.x.
Ceratotoxins A and B are antibacterial peptides produced by the sexually mature females of Ceratitis capitata. The gene expression is restricted to the female reproductive accessory glands, and is not affected by bacterial infection, but is enhanced by mating. We report here the purification and the amino acid sequence of ceratotoxin C, a novel member of the ceratotoxin family, the cloning of its cDNA and the analysis of its expression. Ceratotoxin C is coordinately expressed with the other members of the ceratotoxin family. Its antibacterial activity is directed against both Gram-negative and Gram-positive bacterial strains but it is lower than that of ceratotoxin A. We demonstrate in the genome of C. capitata the presence of at least three ceratotoxin genes which express, in the female accessory glands, a set of peptides presumably involved in the protection of the genital tract during fertilization.
3. The genes encoding the antibacterial sex-specific peptides ceratotoxins are clustered in the genome of the medfly Ceratitis capitata
M Rosetto, T De Filippis, A G Manetti, D Marchini, C T Baldari, R Dallai Insect Biochem Mol Biol. 1997 Dec;27(12):1039-46. doi: 10.1016/s0965-1748(97)00090-8.
Ceratotoxins are antibacterial peptides produced in the female reproductive accessory glands of the medfly Ceratitis capitata. Their expression is not affected by bacterial infection, but is enhanced after mating and is modulated by juvenile hormone. Three different peptides, named ceratotoxins A, B and C, have been previously purified from the female accessory gland secretion and their amino acid and cDNA sequences have been determined. We report here the complete nucleotide sequences of four genes encoding closely related ceratotoxin peptides. One of them encodes a novel peptide, which we named ceratotoxin D. Restriction and nucleotide sequence analysis indicate that these ceratotoxin genes are organized in a large cluster spanning more than 26 kilobases of DNA. All ceratotoxin genes are coordinately expressed. Ceratotoxin transcripts appear in 2-3 day old adult females, and they reach a maximum in 6-7 day old females. The presence of highly conserved motifs in the upstream regions of all the sequenced ceratotoxin genes suggests the presence of common regulatory elements for all ceratotoxins.
