Screening and Identification of Natural Compounds as Potential Inhibitors of Glutamate Racemase, an Emerging Drug Target of Food Pathogen E. coli O157:H7: An In-silico Approach to Combat Increasing Drug Resistance

BACKGROUND: Shiga Toxin-Producing Escherichia coli (E. coli O157:H7), capable of causing serious food-borne illnesses, is extensively studied and is known to be transmitted through animal reservoirs or person-to-person contact, leading to severe disease outbreaks. The emergence of antibiotic resistance in these strains, coupled with increased adverse effects of existing therapeutics, underscores the urgent need for alternative therapeutic strategies. OBJECTIVE: This study aims to evaluate Glutamate Racemase (MurI protein) of the food-path-ogenic E. coli O157:H7 (EC MurI) as a novel drug target. Furthermore, the study seeks to identify new compounds with potential inhibitory effects against this protein. METHODS: Using computational tools, the study identified inhibitor binding sites on EC MurI and identified relevant inhibitors capable of binding to these sites. Molecular docking tech-niques were employed to assess potential hits, and selected compounds were further analyzed for their structural activity and binding affinity to the protein. RESULTS: The results of the study revealed that Frigocyclinone and Deslanoside, exhibited the best binding affinity with EC-MurI. Subsequent molecular dynamic (MD) simulations of the selected complexes indicated that both compounds were stable. This suggests that Frigocy-clinone and Deslanoside have the potential to serve as potent inhibitors of EC-MurI. CONCLUSION: In summary, this study highlights the urgent need for alternative therapies against food-pathogenic E. coli, focusing on E. coli O157:H7. Evaluation of Glutamate Race-mase as a drug target identified Frigocyclinone and Deslanoside as promising inhibitors. MD simulations indicated their stability, suggesting their potential as lead molecules for further research and treatment development.

Silver-Nanoparticle-Embedded Short Amphiphilic Peptide Nanostructures and Their Plausible Application to Reduce Bacterial Infections.

The microbiota-gut-brain axis (GBA) plays a critical role in the development of neurodegenerative diseases. Dysbiosis of the intestinal microbiome causes a significant alteration in the gut microbiota of Alzheimer's disease (AD) patients, followed by neuroinflammatory processes. Thus, AD beginning in the gut is closely related to an imbalance in gut microbiota, and hence a multidomain approach to reduce this imbalance by exerting positive effects on the gut microbiota is needed. In one example, a tyrosine-based short peptide amphiphile (sPA) was used to synthesize antibacterial AgNPs-sPA nanostructures. Such nanostructures showed high biocompatibility and low cytotoxicity, and therefore work as model drug delivery agents for addressing local bacterial infections. These may have therapeutic value for the treatment of microbiota-triggered progression of neurodegenerative diseases.

Amyloid-ß Inspired Short Peptide Amphiphile Facilitates Synthesis of Silver Nanoparticles as Potential Antibacterial Agents.

An amyloid-ß inspired biocompatible short peptide amphiphile (sPA) molecule was used for controlled and targeted delivery of bioactive silver nanoparticles via transforming sPA nanostructures. Such sPA-AgNPs hybrid structures can be further used to develop antibacterial materials to combat emerging bacterial resistance. Due to the excellent antibacterial activity of silver, the growth of clinically relevant bacteria was inhibited in the presence of AgNPs-sPA hybrids. Bacterial tests demonstrated that the high biocompatibility and low cytotoxicity of the designed sPA allow it to work as a model drug delivery agent. It therefore shows great potential in locally addressing bacterial infections. The results of our study suggest that these nanodevices have the potential to trap and then engage in the facile delivery of their chemical payload at the target site, thereby working as potential delivery materials. This system has potential therapeutic value for the treatment of microbiota triggered progression of neurodegenerative diseases.

The nano-bio interactions of rare-earth doped BaF2 nanophosphors shape the developmental processes of zebrafish.

Nanoparticles with biomedical applications should be evaluated for their biocompatibility. Rare-earth doped nanoparticles with unique spectral properties are superior in vivo optical probes in comparison with quantum dots and organic dyes, however, studies describing their nano-bio interactions are still limited. Here, we have evaluated the nano-bio interactions of green-synthesized, phase-pure BaF2 nanoparticles doped with rare-earth (RE3+ = Ce3+/Tb3+) ions using larval zebrafish. We found that zebrafish can tolerate a wide concentration range of these nanoparticles, as the maximal lethality was observed at very high concentrations (more than 200 mg L-1) upon five days of continuous exposure. At a concentration of 10 mg L-1, at which Zn2+, Ti4+ and Ag+ nanoparticles are reported to be lethal to developing zebrafish, continuous exposure to our nanoparticles for four days produced no developmental anomalies, craniofacial defects, cardiac toxicity or behavioural abnormalities in the developing zebrafish larvae. We have also found that the doping of rare-earth ions has no major effect on these biomarkers. Interestingly, the function of acetylcholinesterase (AChE) and the cellular metabolic activity of whole zebrafish larvae remained unchanged, even during continuous exposure to these nanoparticles at 150 mg L-1 for four days; however, severe developmental toxicities were evident at this high concentration. Based on these results, we can conclude that the biocompatibility of rare-earth doped nanoparticles is concentration dependent. Not all biomarkers are sensitive to these nanoparticles. The high concentration-dependent toxicity occurs through a mechanism distinct from changes in the metabolic or AChE activity. The significance of these findings lies in using these nanoparticles for bioimaging applications and biomarker studies, especially for prolonged exposure times.

Polymeric nanoparticles containing diazepam: preparation, optimization, characterization, in-vitro drug release and release kinetic study.

Nanoparticles formulated from biodegradable polymers like poly(lactic-co-glycolic acid) (PLGA) are being extensively investigated as drug delivery systems due to their two important properties such as biocompatibility and controlled drug release characteristics. The aim of this work to formulated diazepam loaded PLGA nanoparticles by using emulsion solvent evaporation technique. Polyvinyl alcohol (PVA) is used as stabilizing agent. Diazepam is a benzodiazepine derivative drug, and widely used as an anticonvulsant in the treatment of various types of epilepsy, insomnia and anxiety. This work investigates the effects of some preparation variables on the size and shape of nanoparticles prepared by emulsion solvent evaporation method. These nanoparticles were characterized by photon correlation spectroscopy (PCS), transmission electron microscopy (TEM). Zeta potential study was also performed to understand the surface charge of nanoparticles. The drug release from drug loaded nanoparticles was studied by dialysis bag method and the in vitro drug release data was also studied by various kinetic models. The results show that sonication time, polymer content, surfactant concentration, ratio of organic to aqueous phase volume, and the amount of drug have an important effect on the size of nanoparticles. Hopefully we produced spherical shape Diazepam loaded PLGA nanoparticles with a size range under 250 nm with zeta potential -23.3 mV. The in vitro drug release analysis shows sustained release of drug from nanoparticles and follow Korsmeyer-Peppas model.

Detection of Mycobacterium leprae DNA for 36kDa protein in urine from leprosy patients: a preliminary report.

We have searched for Mycobacterium leprae DNA for 36kDa protein in urine using a M. leprae specific PCR technique. A limited number of 16 patients (of which 11 belonged to lepromatous leprosy and five to tuberculoid leprosy) and eight healthy individuals were included for the present study. The number of urine samples positive by PCR were 36.4% (4/11) in lepromatous patients and 40% (2/5) in tuberculoid patients. None of the samples from healthy individuals was positive. To our knowledge, the results indicate, for the first time, the presence of M. leprae DNA in urine from leprosy patients. Another important finding obtained out of the study is that amongst treated patients 66.6% (4/6) were positive whereas amongst untreated only 20% (2/10) were positive. From the present indicative data it appears that treatment improves the PCR results with urine as a sample. Thus, the approach could prove to be useful for monitoring the treatment response of individual patients and needs to be further evaluated with a large number of patients.

Detection of Mycobacterium leprae DNA for 36kDa protein in urine from leprosy patients: a preliminary report

Pesquisamos o DNA do Mycobacterium leprae para proteína 36 kDa na urina usando a técnica do PCR específica para M. leprae. Um número limitado de 16 pacientes (dos quais 11 tinham hanseníase multibacilar e cinco hanseníase paucibacilar) e oito indivíduos saudáveis foram incluídos neste estudo. O número de amostras de urina positivas pelo PCR foi de 36,4% (4/11) em pacientes com hanseníase multibacilar e 40% (2/5) em pacientes com hanseníase paucibacilar. Nenhuma das amostras de indivíduos saudáveis foi positiva. Até onde chega o nosso conhecimento, os resultados indicam, pela primeira vez, a presença de DNA do M. leprae na urina de pacientes com hanseníase. Outro fato importante obtido através do exame é que entre os pacientes tratados 66.6% (4/6) eram positivos enquanto entre os não tratados somente 20% (2/10) foram positivos. Pelos presentes dados indicativos parece que o tratamento melhora os resultados do PCR em amostra de urina. Assim, o acesso a estes dados prova ser útil no monitoramento da resposta ao tratamento de pacientes individuais e precisa ser melhor avaliado com um grande número de pacientes.