Clavanin bacterial sepsis control using a novel methacrylate nanocarrier.

Controlling human pathogenic bacteria is a worldwide problem due to increasing bacterial resistance. This has prompted a number of studies investigating peptides isolated from marine animals as a possible alternative for control of human pathogen infections. Clavanins are antimicrobial peptides isolated from the marine tunicate Styela clava, showing 23 amino acid residues in length, cationic properties, and also high bactericidal activity. In spite of clear benefits from the use of peptides, currently 95% of peptide properties have limited pharmaceutical applicability, such as low solubility and short half-life in the circulatory system. Here, nanobiotechnology was used to encapsulate clavanin A in order to develop nanoantibiotics against bacterial sepsis. Clavanin was nanostructured using EUDRAGIT(®) L 100-55 and RS 30 D solution (3:1 w:w). Atomic force, scanning electron microscopy and dynamic light scattering showed nanoparticles ranging from 120 to 372 nm in diameter, with a zeta potential of -7.16 mV and a polydispersity index of 0.123. Encapsulation rate of 98% was assessed by reversed-phase chromatography. In vitro bioassays showed that the nanostructured clavanin was partially able to control development of Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Furthermore, nanostructures did not show hemolytic activity. In vivo sepsis bioassays were performed using C57BL6 mice strain inoculated with a polymicrobial suspension. Assays led to 100% survival rate under sub-lethal sepsis assays and 40% under lethal sepsis assays in the presence of nanoformulated clavanin A until the seventh day of the experiment. Data here reported indicated that nanostructured clavanin A form shows improved antimicrobial activity and has the potential to be used to treat polymicrobial infections.

A novel antimicrobial peptide from Crotalaria pallida seeds with activity against human and phytopathogens.

An actual severe problem in agriculture consists of an expressive increase of economical losses caused by fungi and resistant bacteria toward antibiotics. In order to find a solution to this problem, several studies have been concentrating on the screening of novel plant defense peptides with antimicrobial activities. These peptides are commonly characterized by having low molecular masses and cationic charges. The present work reports the purification and characterization of a novel plant peptide with molecular mass of 5340 Da, named Cp-AMP, from seeds of C. pallida, a typical plant from Caatinga biome. Purification was achieved using a size exclusion S-200 column followed by reversed-phase chromatography on Vydac C18-TP column. In vitro assays indicated that Cp-AMP was able to inhibit the development of filamentous fungi Fusarium oxysporum as well as the gram-negative bacterium Proteus sp. The identification of Cp-AMP could contribute, in the near future, to the development of biotechnological products, such as transgenic plants with enhanced resistance to pathogenic fungi and/or of antibiotics production derived from plant sources in order to control bacterial infections.