Atomic force microscopy evaluation of the effects of a novel antimicrobial multimeric peptide on Pseudomonas aeruginosa.
In this article we evaluated by atomic force microscopy (AFM) the effects of the (novel) tetrabranched antimicrobial peptide SB006 on morphology and mechanical properties of the gram-negative bacterium Pseudomonas aeruginosa. AFM imaging showed that SB006 causes the appearance of significant fragmentariness in the bacterial membrane and a severe volume decrease. Quantitative evaluation of the degree of fragmentariness was allowed by a new ad hoc image analysis procedure. The rigidity of the treated and untreated bacteria was measured through AFM tip nanoindentation measurements, and no differences registered. These results support the membrane interaction hypothesis, according to which SB006 targets the bacterial membranes and disrupts their permeability (allowing the leakage of cytoplasmic material and the subsequent shrinkage), but it does not affect the bacterium wall, which determines its rigidity.
Rossetto
Greta
G
INSTM and Laboratorio di Chimica per le Tecnologie, Università di Brescia, Brescia, Italy.
Bergese
Paolo
P
Colombi
Paolo
P
Depero
Laura E
LE
Giuliani
Andrea
A
Nicoletto
Silvia F
SF
Pirri
Giovanna
G
D023181:Antimicrobial Cationic Peptides / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000648:ultrastructure*; D004548:Elasticity; D008846:Micromanipulation / Q000379:methods*; D018625:Microscopy, Atomic Force / Q000379:methods*; D011487:Protein Conformation; D011550:Pseudomonas aeruginosa / Q000737:chemistry* / Q000648:ultrastructure*; D013314:Stress, Mechanical
D023181:Antimicrobial Cationic Peptides; D001426:Bacterial Proteins