Ning Han,Jie Li,Feifei Zhao,Yangyang Li,Jun Wang,Xiaolan Dai,Dongping Zeng,Wenguang Xiong,Zhenling Zeng
Streptococcus suis, an encapsulated zoonotic pathogen, has been reported to cause a variety of infectious diseases, such as meningitis and streptococcal-toxic-shock-like syndrome. Increasing antimicrobial resistance has triggered the need for new treatments. In the present study, we found that isopropoxy benzene guanidine (IBG) significantly attenuated the effects caused byS. suisinfection, in vivo and in vitro, by killingS. suisand reducingS. suispathogenicity. Further studies showed that IBG disrupted the integrity ofS. suiscell membranes and increased the permeability ofS. suiscell membranes, leading to an imbalance in proton motive force and the accumulation of intracellular ATP. Meanwhile, IBG antagonized the hemolysis activity of suilysin and decreased the expression ofSlygene. In vivo, IBG improved the viability ofS. suisSS3-infected mice by reducing tissue bacterial load. In conclusion, IBG is a promising compound for the treatment ofS. suisinfections, given its antibacterial and anti-hemolysis activity.Keywords:Streptococcus suis;isopropoxy benzene guanidine;antibacterial;anti-hemolysis;suilysin
Hafiz Abdul Rasheed,Abdur Rehman,Xiaochen Chen,Tariq Aziz,Fahad Al-Asmari,Majid Alhomrani,Abdulhakeem S. Alamri,Haiying Cui,Lin Lin
Listeria monocytogenes is a prominent cause of foodborne illnesses and public health concerns worldwide. Naturally active compounds have been extensively explored for their potential to reduce foodborne pathogenic contamination. This work is designed to study the chemical composition, antibacterial effect , and inhibition mechanism of Citrus bergamia essential oil (CB-EO) against L. monocytogenes . The CB-EO composition revealed the major components of the total account are d -limonene (23.2%), linalyl acetate (14.01%), and linalool (9.96%). The inhibitory effect was examined at different concentrations of CB-EO, and the MIC value was 1.5 mg/mL against L. monocytogenes . The CB-EO concentration of 1.5 mg/mL significantly disturbed the membrane permeability and fluidity, leading to leakage of intracellular protein and DNA constituents, as revealed by the BCA protein assay and UV–Vis spectrophotometric analysis, respectively. However, a decrease in concentration to 0.75 mg/mL indicated a significant decline in intracellular macromolecule leakage as well as membrane disruption. Moreover, SEM and CLSM observations provided extensive insight into the inhibition mechanism of CB-EO against L. monocytogenes . Finally, while investigating the anti-hemolysis activity, CB-EO and its major compounds, limonene , linalool, and linalyle acetate, have been found to be effective against the virulence agent listeriolysin O (LLO). Thus, it was proposed that CB-EO could act on L. monocytogenes cells through multiple mechanisms of action, with EO concentration providing a crucial role in determining the mode of action. This work offers deep insight into the inhibition mechanisms of natural substances, expanding the potential uses of CB-EO as a natural antimicrobial.
Poor safety and effectiveness is an outstanding challenge in the preparation of drug delivery systems (DDS) for cancer treatment. The pursuit of the high curative effect will inevitably increase the risk of adverse side effects. Herein, a bio-safe DDS was constructed by combining the advantages of functional zein and Au doped mesoporous silica nanoparticles ( [email protected] 2 ) to achieve chemo-photothermal therapy. The cRGD functionalized zein (cRGD-Zein) was coated on the surface of [email protected] 2 which effectively avoided premature leakage of paclitaxel and realized sustained drug release. Meanwhile, the high hemolysis rate (107%) of [email protected] 2 had been significantly reduced to 4%. The anti-hemolysis mechanism of functionalized zein was explored to give a deeper understanding of the interaction between nanoparticles and RBCs. The results showed that the functional zein would change the protein conformation during the interaction with [email protected] 2 to protect the RBCs from the damage of [email protected] 2 . And the release rate of hemoglobin was limited by the size of RBCs membrane cracks with approximately 40 nm in width and 470 nm in length. The cell cytotoxicity and uptake assays showed that the prepared DDS exhibited low tumour cell viability (35%) and enhanced uptake performance (99.3%). This work suggested that the prepared nanoparticles could serve as a promising carrier to achieve safe and efficacious tumour therapy.
危险品化学品经营许可证（带存储）