Mechanisms of antimicrobial peptides as characterized by solid-state NMR

Antimicrobial peptides(AMP)are small proteins that play critical roles in host defense against microbe invasion.Many AMPs disrupt the cellular membrane of microbe,while the mechanism of action of AMPs can be very sophisticated.Solid-state NMR(SSNMR)technique is powerful in characterizing the mechanism of AMPs in vivo and in vitro.This review summarizes the recent advance of SSNMR technique in AMP mechanisms characterization.We highlight the sample preparation approaches,the SSNMR spectroscopic methods,and a number of outstanding examples of AMP mechanisms elucidated via SSNMR spectroscopy.

The lasso structure,biosynthesis,bioactivities and potential applications of Microcin J25:A novel antibacterial agent with unique mechanisms

The overuse and misuse of traditional antimicrobial drugs have led to their weakened effectiveness and the emergence of pathogenic bacterial resistance.Consequently,there has been growing interest in alternative op-tions such as antimicrobial peptides(AMPs)in the pharmaceutical industry.Microcin J25(MccJ25)has gained significant attention for its potent inhibitory effect on a diverse range of pathogens.Its unique rotaxane structure provides exceptional stability against extreme thermal,pH,and protease degradation,including chymotrypsin,trypsin,and pepsin.Given its remarkable stability and diverse bioactivity,we aim to provide an overview of the physicochemical properties,the mechanism underlying its antimicrobial activity,and the critical functional residues of MccJ25.Additionally,we have summarized the latest strategies for the heterologous expression of MccJ25,and its potential medical use and other applications.

A perspective on general direction and challenges facing antimicrobial peptides

The emergence of drug resistant bacterium threatens the global public healthcare systems.The urgent need to obtain new antimicrobials has driven antimicrobial peptides（AMPs） research into spotlight.Here we give a brief introduction of the recent progress of AMPs regarding their structures,properties,production and modification,and antimicrobial mechanism.Thereby,this review will give an insight into the trends and challenges facing on this particular kind of antimicrobial materials.

Fabrication linalool-functionalized hollow mesoporous silica spheres nanoparticles for efficiently enhance bactericidal activity

To develop a novel food preservation technology for efficiently enhance bactericidal activity in a long term,hollow mesoporous silica spheres(HMSS)with regular nanostructures were applied to encapsulate natural organic antimicrobial agents.The chemical structures,morphologies and thermal stabilities of linalool,HMSS and linalool-functionalized hollow mesoporous silica spheres(L-HMSS)nanoparticles were evaluated by polarimeter,field emission scanning electron microscope(FE-SEM),transmission electron microscope(TEM),fourier transform infrared(FT-IR),thermal gravimetric analyzer(TGA),nitrogen adsorption-desorption,zeta potential and small angle X-ray diffraction(SXRD).The results show that the linalool was successfully introduced into the cavities of HMSS,and the inorganic host exhibited a high loading capacity of about 1500 mg/g.In addition,after 48 h of incubatio n,the minimum bactericidal concentrations(MBC)of L-HMSS against Escherichia coli(E.coli),Salmonella enterica(S.enterica)and Staphylococcus aureus(S.aureus),Listeria monocytogenes(L.monocytogenes)were decreased to be 4(<5)mg/mL and 8(<10)mg/mL,respectively.These results revealed linaloolfunctionalized hollow mesoporous spheres could efficiently improve the bactericidal activities of the organic component.Furthermore,SEM images clearly showed that L-HMSS indeed had an extremely inhibitory effect against gram-negative(E.coli)and gram-positive(S.aureus)by breaking the structure of the cell membrane.This research is of great significance in the application of linalool in nano-delivery system as well as food industry.

Effect of Cu Addition in Pipeline Steels on Microstructure,Mechanical Properties and Microbiologically Influenced Corrosion

In the present study, Cu-modified pipeline steels were fabricated to mitigate MIC by the antimicrobial ability of Cu element. The microstructure, mechanical properties and the antimircobial performance of the Cu-modified steel were systematically investigated. The Cu-modified steels showed good antimicrobial performance with remarkable strength enhancement by nanoscale Cu-rich precipitates and good impact toughness without changing the original base microstructures after the optimal aging treatment of 500 °C/1 h.