Background Bioactive glasses (BGs) have attracted added attention in the structure of the scaffolds for bone repair applications. Different metal ions could be doped in BGs to induce specific biological responses. Among these ions, strontium (Sr) is considered as an effective and safe doping element with promising effects on bone formation and regeneration. Methods In this experiment, we evaluated the antibacterial activities of the gelatin-BG (Gel-BG) and Gel-BG/Sr scaffolds in vitro. The osteogenic properties of the prepared scaffolds were also assessed in rabbit calvarial bone defects for 12 weeks. Alizarin Red, Hematoxylin & Eosin (H&E) and Masson’s Trichrome staining were performed to assess bone regeneration and the obtained results were compared with those without Sr. Also, histomorphometric data were obtained to evaluate the new bone, residual graft, and connective tissue. Results Both scaffolds showed in vivo bone formation during 12 weeks with the newly formed bone area in Gel-BG/Sr scaffold was higher than that in Gel-BG scaffolds after the whole period. Based on the histological results, Gel-BG/Sr exhibited acceleration of early-stage bone formation in vivo. The results of antibacterial investigation showed that although both Gel-BG/Sr and Gel-BG effectively inhibited the growth of Escherichia coli (E. coli) but, only Gel-BG/Sr structure could lead to a 3 log reduction in Staphylococcus aureus (S. aureus). Conclusions: Our results confirmed that Sr doped BG is a favorable candidate for bone tissue engineering with superior antibacterial activity and bone regeneration capacity compared with similar counterparts having no Sr ion.
Vancomycin-intermediate resistant Staphylococcus aureus (VISA), one of the common causes of nosocomial infection, is developed by mutations, including in walKR, with unclear molecular mechanisms. Although studies have verified some of these mutations, there are a few studies to pay attention to the importance of molecular modeling of mutations. Here, the Sanger sequencing for comparing gene sequences of WlKR between a VISA and its parental strain revealed mutation WalK-H364R. Structural protein mapping showed that H364R was located in a functional zinc ion coordinating residue within the cytoplasmic Per-Arnt-Sim (PAS) domain. The structural and functional effects of this mutation were analyzed using molecular computational approaches based on the recently determined crystal structures of the PAS domain of S. aureus. WalK-H364R was predicted to destabilize protein and decrease WalK interactions with proteins and nucleic acids. The qRT-PCR method showed downregulation of walKR and WalKR-regulated autolysins, which verified the molecular computational results.Overall, WalK-H364R within a critical metal-coordinating site is linked to VISA development through the walKR gene expression changes as well as the destructive effects on protein.Therefore, molecular modeling can be provided detailed insight into the molecular mechanism of VISA development, in particular, where complementation experiments are not readily available.
Objective: Vaccination is an important strategy for the eradication of infectious diseases. CadF protein of Campylobacter jejuni is one of the important factors in the pathogenesis of this bacterium. The purpose of this work was to perform a bioinformatics study to identify an epitope-based CadF vaccine, as a subunit vaccine. Full protein sequences of CadF were extracted from the NCBI and UniProt databases and subjected to in silico evaluations, including sequence analysis, allergenicity, antigenicity, epitope conservancy, and molecular docking assessments done by different servers. Results: The results showed that CadF was a highly conserved protein belonging to the outer member proteins superfamily. Among the evaluated epitopes, LSDSLALRL was identified as an antigenic and non-allergenic peptide with a suitable structure for vaccine development. It was also able to stimulate both T and B cells. This 9-mer peptide was located in 136-144 segment of CadF protein and interacted with both HLA-A 0101 and HLA-DRB1 0101 alleles. Overall, the obtained theoretical results showed that CadF protein could be used for designing and evaluating a new effective vaccine against C. jejuni.
Background: Bioactive glasses (BGs) have attracted added attention in the structure of the scaffolds for bone repair applications. Different metal ions could be doped in BGs to induce specific biological responses. Among these ions, strontium (Sr) is considered as an effective and safe doping element with promising effects on bone formation and regeneration.Methods: In this experiment, we evaluated the antibacterial activities of the gelatin-BG (Gel-BG) and Gel-BG/Sr scaffolds in vitro. The osteogenic properties of the prepared scaffolds were also assessed in rabbit calvarial bone defects for 12 weeks. Alizarin Red, Hematoxylin & Eosin (H&E) and Masson’s Trichrome staining were performed to assess bone regeneration and the obtained results were compared with those without Sr. Also, histomorphometric data were obtained to evaluate the new bone, residual graft, and connective tissue.Results: Both scaffolds showed in vivo bone formation during 12 weeks with the newly formed bone area in Gel-BG/Sr scaffold was higher than that in Gel-BG scaffolds after the whole period. Based on the histological results, Gel-BG/Sr exhibited acceleration of early-stage bone formation in vivo. The results of antibacterial investigation showed that although both Gel-BG/Sr and Gel-BG effectively inhibited the growth of Escherichia coli (E. coli) but, only Gel-BG/Sr structure could lead to a 3 log reduction in Staphylococcus aureus (S. aureus). Conclusions: Our results confirmed that Sr doped BG is a favorable candidate for bone tissue engineering with superior antibacterial activity and bone regeneration capacity compared with similar counterparts having no Sr ion.
Infections caused by multidrug resistant (MDR) Pseudomonas aeruginosa isolates in burn patients restrict therapeutic strategies. The current study aimed to analyze antibiotic resistance genes and multilocus sequence typing (MLST) of P. aeruginosa strains isolated from burn patients in Shahid Motahari hospital in Tehran, Iran.Altogether 63 P. aeruginosa isolates were characterized in this study. Antibiotic susceptibility testing was performed by disc diffusion method. PCR was performed to determine the frequency of resistance genes. The expression rates of mexB, mexY genes were evaluated by Real-Time PCR. Genotyping of isolates was performed by MLST analysis. All isolates were MDR in this study. The highest resistance was detected against gentamicin, tobramycin, and cefoxitin (100%), while all isolates were susceptible to colistin. Altogether 14 resistance profiles were determined, and profile 1 included more than 50% of the isolates with the highest resistance. In this study blaampC, blaVIM-2, blaOXA-10, and aac(6′)-Ib resistance genes were detected in all isolates. The expression levels of mexB and mexY genes were upregulated in 66.6 and 88.8% of MDR isolates, respectively. Overexpression of both genes was detected in 55.5% of the isolates.MLST analysis revealed five sequence types (STs), including ST235, ST664, ST532, ST2637, and ST230, which showed a significant relationship with antibiotic resistance profiles. The present study indicates an increase in antibiotic resistance against different antibiotic families among P. aeruginosa isolates. We describe the circulation of globally distributed STs among hospitalized patients, and we report ST235 as the most common MDR clone in our study.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.