Bactericidal activities of lysozyme and aprotinin against Gram‐negative and Gram‐positive bacteria related to their basic character

Abstract

Bactericidal properties of aprotinin, a proteinase inhibitor and possibly a defence molecule in bovine species, and of chicken egg white lysozyme, known as muramidase, were investigated. Incubation of various bacteria in the presence of either aprotinin or lysozyme showed that both proteins killed Gram-positive as well as Gram-negative bacteria without addition of complement or EDTA. Denaturation of the two proteins by dithiothreitol did not lead to loss of their bactericidal potency. Electron microscopic examination of Escherichia coli incubated either with lysozyme or aprotinin revealed that the bacterial cytoplasms gradually disintegrated. Both aprotinin and lysozyme were demonstrated within the affected cytoplasm by immunogold labelling. The results suggest that the bactericidal potency of lysozyme is not only due to muramidase activity but also to its cationic and hydrophobic properties. The bactericidal activity of aprotinin is probably also related to both these properties rather than to its activity as proteinase inhibitor.

Extracellular serine-proteinases isolated from Streptomyces alboniger: Partial characterization and effect of aprotinin on cellular structure

“…When S. alboniger was grown in the presence of aprotinin its growth was partially or completely inhibited depending on the inhibitor concentration. Ultrastructural analysis showed a low electron density of the cell wall and of the septum as well as a little swelling of the bacterial body consistent with the observations of Pellegrini et al (1992). The images exhibited centrally the genetic material, displaying a more condensed structure.…”

“…In particular one of them indicated that serine-proteinases may be involved in the conversion of chromatin into an acceptable DNA polymerase substrate, probably acting upon nuclear proteins involved in DNA folding (Jensen & O'Leary 1990). On the other hand, the S. alboniger DNA alterations detected after aprotinin treatment could be due to antibacterial activity of the inhibitor as shown previously (Pellegrini et al 1992).…”

Identification of an aprotinin antiviral domain

“…However, no control experiments were performed using inactivated aprotinin. While aprotinin also has antibacterial properties [8,11], these are most probably unrelated to its antiproteinase activity [11].…”

“…We recently reported that the bactericidal and antiproteolytic activities of aprotinin are not related and suggested that the bactericidal potency of aprotinin is due instead to its cationic and hydrophobic properties [11].…”

Analysis of Egg White Lysozyme Polymorphisms among Japanese Quail Populations in Japan and France

“…Lysozyme is one of the best characterized antimicrobial proteins in albumen, and comprises approximately 3.5% of the protein in egg white. Lysozyme exhibits an antibacterial activity against gram positive bacteria and some gram negative bacteria (Burley and Vadehra, 1989;Pellegrini et al, 1992;Ibrahim et al, 2002;Bera et al, 2005). The antibacterial properties of lysozyme are utilized widely in food manufacturing, cosmetics, pharmaceuticals, and human and veterinary medicine (Rzedzicki and Stępień-Pyśniak, 2009;Mastromatteo et al, 2010;Sung et al, 2011).…”