Coupling Plant-Derived Cyclotides to Metal Surfaces: An Antibacterial and Antibiofilm Study

Abstract

Modification of metal surfaces with antimicrobial peptides is a promising approach to reduce bacterial adhesion. Here, cyclic peptides or cycloids, possessing remarkable stability and antimicrobial activities, were extracted and purified from Viola philippica Cav., and identified using mass spectrometry. Cyclotides were subsequently utilized to modify stainless steel surfaces via polydopamine-mediated coupling. The resulting cyclotide-modified surfaces were characterized by Fourier transform infrared (FTIR) spectroscopy and contact angle analysis. The antibacterial capacity of these cyclotides against Staphylococcus aureus was assessed by Alamar blue assay. The antibiofilm capacity of the modified surfaces was assessed by crystal violet assay, and scanning electron microscopy (SEM). A composite of Kalata b1, Varv A, Viba 15 and Viba 17 (P1); Varv E (P2); and Viphi G (P3) were isolated and identified. FTIR analysis of the modified surfaces demonstrated that cyclotides bound to the surfaces and induced reduction of contact angles. Antimicrobial effects showed an order P3 > P1 and P2, with P3-treated surfaces demonstrating the strongest antibiofilm capacity. SEM confirmed reduced biofilm formation for P3-treated surfaces. This study provides novel evidence for cyclotides as a new class for development of antibacterial and antibiofilm agents.

Magnetic immobilization of a quorum sensing signal hydrolase, AiiA

“…The biofilm formation was quantified using the crystal violet staining method (Cao, Yang, Uche, Hart, & Li, ; Vinoj, Pati, Sonawane, & Vaseeharan, ). Different amount of IB@[AiiA‐MagR] (0, 0.025, 0.05, 0.1, 0.2, 0.4 mg) was added into 24‐well suspension culture plates.…”

Modification of metal surfaces using TCM-derived cyclotides: an antibacterial and antibiofilm study

“…We therefore propose that TCM-derived cyclotides, with their unique three-dimensional structure and remarkable stability, can serve as a novel source of biological materials to be used for the modification of metal surfaces in medical devices, aquaculture, food manufacture and shipbuilding devices. This study provides novel evidence for cyclotides as a new class for development of antibacterial and antibiofilm agents (6).…”

“…The antibacterial capacity of these cyclotides against Staphylococcus aureus was assessed by Alamar blue assay. The antibiofilm capacity of the modified surfaces was assessed by crystal violet assay, and scanning electron microscopy (SEM) (6).…”

“…Cyclotides are a family of plant disulfide-rich peptides arranged in a knotted pattern which is connected via cysteine residues with a combinatorial cyclic backbone (3,4). These structural features bestow on the cyclotides not only a remarkable stability, but also various biological activities including antibacterial (5,6), antifouling effects(7) and anti-HIV(8) activities. Viola species (Violaceae family) contain an abundance of cyclotides (5).…”

Designing a Minimal Synthetase

“…Although RNA molecules possess many properties crucial for life like the ability to store information, ability to evolve and catalysis their creation in the prebiotic environment remains uncertain [1]. Peptides and amino acids, on the other hand, have been proven to be produced in a variety of prebiotic reactions [2,3,4,5,6] which makes them probably first life-related organic polymers on Earth [7].…”