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  • Synergistic action of Galleria mellonella apolipophorin III and lysozyme against Gram-negative bacteria.

Synergistic action of Galleria mellonella apolipophorin III and lysozyme against Gram-negative bacteria.

Biochimica et biophysica acta (2013-02-20)
Agnieszka Zdybicka-Barabas, Sylwia Stączek, Paweł Mak, Krzysztof Skrzypiec, Ewaryst Mendyk, Małgorzata Cytryńska
ABSTRACT

Insect immune response relies on the humoral and cellular mechanisms of innate immunity. The key factors are the antimicrobial polypeptides that act in concert against invading pathogens. Several such components, e.g. apolipophorin III (apoLp-III), lysozyme, and anionic peptide 2, are present constitutively in the hemolymph of non-challenged Galleria mellonella larvae. In the present study, we demonstrate an evidence for a synergistic action of G. mellonella lysozyme and apoLp-III against Gram-negative bacteria, providing novel insights into the mode of action of these proteins in insect antimicrobial defense. It was found that the muramidase activity of G. mellonella lysozyme considerably increased in the presence of apoLp-III. Moreover, apoLp-III enhanced the permeabilizing activity of lysozyme toward Escherichia coli cells. As shown using non-denaturing PAGE, the proteins did not form intermolecular complexes in vivo and in vitro, indicating that the effect observed was not connected with the intermolecular interactions between the proteins. Analysis of AFM images of E. coli cells exposed to G. mellonella lysozyme and/or apoLp-III revealed evident alterations in the bacterial surface structure accompanied by the changes in their biophysical properties. The bacterial cells demonstrated significant differences in elasticity, reflected by Young's modulus, as well as in adhesive forces and roughness values in comparison to the control ones. The constitutive presence of these two defense molecules in G. mellonella hemolymph and the fact that apoLp-III enhances lysozyme muramidase and perforating activities indicate that they can be regarded as important antibacterial factors acting at the early stage of infection against Gram-negative as well as Gram-positive bacteria.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Lysozyme human, Lysobac, recombinant, expressed in rice, ≥100,000 units/mg protein, lyophilized powder
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Lysozyme from human neutrophils, ≥95% (SDS-PAGE), lyophilized powder, ≥100,000 units/mg protein (E1%/280)
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Lysozyme from chicken egg white, BioUltra, lyophilized powder, ≥98% (SDS-PAGE), ≥40,000 units/mg protein
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Lysozyme from chicken egg white, 10 mg/mL
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Lysozyme from chicken egg white, powder (crystalline), 70000-140000 U/mg
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Lysozyme from chicken egg white, dialyzed, lyophilized, powder, ~100000 U/mg
Sigma-Aldrich
Lysozyme from chicken egg white, For use as a marker in SDS-PAGE
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Lysozyme from chicken egg white, aseptically filled
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Lysozyme from chicken egg white, powder or granules, ≥90 %, ≥39,000 units/mg protein
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Lysozyme chloride form from chicken egg white, Grade VI, ≥35,000 units/mg protein (E1%/282)