amineh sadat tajani

Bacterial infections are treated with antibiotics, but the development of multi-drug resistant strains, which are growing at an increasing rate, is a phenomenon that threatens human societies. Therefore, alternative strategies are needed to combat infectious diseases. Today, compounds that reduce the pathogenicity of bacteria and do not interfere with their survival or growth are introduced as the next generation of antibiotics. Pseudomonas aeruginosa is one of the important and hazardous pathogens that employs its quorum-sensing network to regulate pathogenicity and virulence factors production. Here, we investigated the effect of a natural naphthoquinone compound, Lawsone (isolated from Henna), and its synthetic derivatives on the quorum-sensing system of P. aeruginosa PAO1.

First, the MIC of each compound was evaluated. Then, the effect of the selected compounds on biofilm formation and survival rate of biofilm sessile cells was investigated by colorimetric method. Finally, the virulence factors secretion of P. aeruginosa, including pyocyanin, pyoverdine, and protease was studied in the presence of the selected compounds.

The results indicated that Lawsone and NO2-481 reduced the production of P. aeruginosa biofilm by about 79% and 92%, respectively. Moreover, Lawsone and NO2-481 (at both concentrations, 250 and 125 µg/mL) decreased the viability of biofilm cells by about 70%. Furthermore, NO2-481 reduced the production of virulence factors including pyocyanin and pyoverdine by about 55% and 81%, respectively; however, it did not affect the protease production.

NO2-481 derivative has the ability to reduce the pathogenicity of P. aeruginosa, and if it is proven to be non-cytotoxic, it can be assessed through animal and clinical studies, to be applied as an alternative compound along with antibiotics or disinfectants

The in vivo efficacy of nanoliposomal formulation of vancomycin against methicillin-resistant Staphylococcus aureus (MRSA) assessed.

Nanoliposomal formulations were prepared and characterized. The in vivo study was carried out on rabbits which received liquid culture medium containing MRSA under anesthesia. After 48 hr, the eyes treated with the liposomal and free form of vancomycin. The rabbits were euthanized at predesignate intervals at 12, 24, 48, 96, 144 hr intervals injection. The antibacterial activity of different vancomycin formulations was assayed by the time killing method.

The zeta potential, mean sizes and encapsulation efficacy of liposomal vancomycin were 29.7 mV, 381.93±30.13 nm and 47%, respectively. The results of time–killing studies indicated that the liposomal formula was more effective than the free form of vancomycin.

The results of this study revealed that liposomal vancomycin formulation is a powerful nano-antibacterial agent to combat infectious endophthalmitis.

Hepatitis C virus (HCV) infection is one of the most prevalent infectious diseases responsible for high morbidity and mortality worldwide. Therefore, designing new and effective therapeutics is of great importance. The aim of the current study was to construct a DNA vaccine containing structural proteins of HCV and evaluation of its expression in a eukaryotic system.
Structural proteins of HCV (core, E1, and E2) were isolated and amplified from JFH strain of HCV genotype 2a using PCR method. The PCR products were cloned into pCDNA3.1 () vector and finally were confirmed by restriction enzyme analysis and sequencing. The eukaryotic expression of the vector was confirmed by RT-PCR.
Recombinant vector containing 2241bp fragment of HCV structural genes was constructed.The desired plasmid was sequenced and corresponded to 100% identity with the submitted sequences in GenBank. RT-PCR results indicated that the recombinant plasmid could be expressed efficiently in the eukaryotic expression system.
Successful cloning of structural viral genes in pCDNA3.1 () vector and their expression in a eukaryotic expression system facilitates the development of new DNA vaccines against HCV. A DNA vaccine encoding core-E1-E2 antigens was designed. The desired expression vector can be used for further attempts in the development of vaccines.