scholarly journals In silico and in vitro analysis of recombinant arginine deiminase from Pseudomonas furukawaii as a potential anticancer enzyme

2021 ◽  
Author(s):  
Rakhi Dhankhar ◽  
Vatika Gupta ◽  
Aparajita Mohanty ◽  
Pooja Gulati
Keyword(s):  
In Silico ◽  
3D Structure ◽  
Cell Epitope ◽  
Mycoplasma Hominis ◽  
Arginine Deiminase ◽  
Phase Iii ◽  
Drug Candidate ◽  
Phase Iii Clinical Trials ◽  
Vitro Analysis

Abstract Arginine deiminase (ADI) is a promising anticancer enzyme that can be employed in amino acid deprivation therapy for the treatment of various arginine auxotrophic tumors. In our previous work, Pseudomonas furukawaii was identified as a potent producer of ADI with optimum activity at physiological pH and temperature. The 3D structure of PfADI was modeled. Immunoinformatics analysis was also carried out to compare the immunogenicity of PfADI with MhADI (Mycoplasma hominis ADI, which is in phase III clinical trials). The PfADI was found to be less immunogenic in terms of number of linear and conformational B cell epitopes and T cell epitope density. The overall antigenicity and allergenicity of PfADI was also lower as compared to MhADI. Thus, the ADI coding arcA gene was cloned and expressed in E. coli BL21. Recombinant ADI of P. furukawaii (PfADI) was purified using affinity chromatography and its molecular mass was estimated to be ~46KDa. PfADI was found to effectively inhibit the HepG2 cells with an IC50 value of 0.1950 IU/ml. PfADI was characterized and the enzyme was found to be stable at human physiological conditions (pH 7 and 37 ⁰C temperature). The Km and Vmax values were found to be 1.90 mM and 1.83 µmol ml-1min-1 respectively. Thus the present in vitro and in silico studies establish PfADI as a potential anticancer drug candidate with improved efficacy and low immunogenicity.

scholarly journals Conservation of S20 as an Ineffective and Disposable IFNγ-Inducing Determinant of Plasmodium Sporozoites Indicates Diversion of Cellular Immunity

2021 ◽  
Vol 12 ◽  
Author(s):  
Calvin Hon ◽  
Johannes Friesen ◽  
Alyssa Ingmundson ◽  
Diana Scheppan ◽  
Julius C. R. Hafalla ◽  
...  
Keyword(s):  
Genetic Background ◽  
Cell Epitope ◽  
Specific Protein ◽  
Phase Iii ◽  
Mammalian Host ◽  
Pivotal Phase ◽  
Phase Iii Clinical Trials ◽  
Immunogenic Proteins

Despite many decades of research to develop a malaria vaccine, only one vaccine candidate has been explored in pivotal phase III clinical trials. This candidate subunit vaccine consists of a portion of a single Plasmodium antigen, circumsporozoite protein (CSP). This antigen was initially identified in the murine malaria model and shown to contain an immunodominant and protective CD8+ T cell epitope specific to the H-2Kd (BALB/c)-restricted genetic background. A high-content screen for CD8+ epitopes in the H2Kb/Db (C57BL/6)-restricted genetic background, identified two distinct dominant epitopes. In this study, we present a characterization of one corresponding antigen, the Plasmodium sporozoite-specific protein S20. Plasmodium berghei S20 knockout sporozoites and liver stages developed normally in vitro and in vivo. This potent infectivity of s20(-) sporozoites permitted comparative analysis of knockout and wild-type parasites in cell-based vaccination. Protective immunity of irradiation-arrested s20(-) sporozoites in single, double and triple immunizations was similar to irradiated unaltered sporozoites in homologous challenge experiments. These findings demonstrate the presence of an immunogenic Plasmodium pre-erythrocytic determinant, which is not essential for eliciting protection. Although S20 is not needed for colonization of the mammalian host and for initiation of a blood infection, it is conserved amongst Plasmodium species. Malarial parasites express conserved, immunogenic proteins that are not required to establish infection but might play potential roles in diverting cellular immune responses.

In Vitro Activity of Gepotidacin Against Gram-negative and Gram-positive Anaerobes

2021 ◽  
Author(s):  
Meredith A. Hackel ◽  
James A. Karlowsky ◽  
Michele A. Canino ◽  
Daniel F. Sahm ◽  
Nicole E. Scangarella-Oman
Keyword(s):  
Clinical Trials ◽  
Vitro Activity ◽  
Phase Iii ◽  
In Vitro Activity ◽  
Gram Positive ◽  
Gram Negative ◽  
Phase Iii Clinical Trials ◽  
Agar Dilution

Gepotidacin (formerly GSK2140944) is a first in class triazaacenaphthylene antibacterial currently in Phase III clinical trials. When tested against Gram-negative ( n =333) and Gram-positive ( n =225) anaerobes by agar dilution, gepotidacin inhibited 90% of isolates (MIC 90 ) at concentrations of 4 and 2 μg/ml, respectively. Given gepotidacin’s in vitro activity against the anaerobic isolates tested, further study is warranted to better understand gepotidacin’s utility in the treatment of infections caused by clinically relevant anaerobic organisms.

Activities of Tobramycin and Six Other Antibiotics against Pseudomonas aeruginosa Isolates from Patients with Cystic Fibrosis

1999 ◽  
Vol 43 (12) ◽  
pp. 2877-2880 ◽  
Author(s):  
Ribhi M. Shawar ◽  
David L. MacLeod ◽  
Richard L. Garber ◽  
Jane L. Burns ◽  
Jenny R. Stapp ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Antimicrobial Agents ◽  
Active Drug ◽  
Resistance Mechanisms ◽  
Phase Iii ◽  
In Vitro Activity ◽  
Phase Iii Clinical Trials ◽  
Multiple Antibiotics

ABSTRACT The in vitro activity of tobramycin was compared with those of six other antimicrobial agents against 1,240 Pseudomonas aeruginosa isolates collected from 508 patients with cystic fibrosis during pretreatment visits as part of the phase III clinical trials of tobramycin solution for inhalation. The tobramycin MIC at which 50% of isolates are inhibited (MIC50) and MIC90 were 1 and 8 μg/ml, respectively. Tobramycin was the most active drug tested and also showed good activity against isolates resistant to multiple antibiotics. The isolates were less frequently resistant to tobramycin (5.4%) than to ceftazidime (11.1%), aztreonam (11.9%), amikacin (13.1%), ticarcillin (16.7%), gentamicin (19.3%), or ciprofloxacin (20.7%). For all antibiotics tested, nonmucoid isolates were more resistant than mucoid isolates. Of 56 isolates for which the tobramycin MIC was ≥16 μg/ml and that were investigated for resistance mechanisms, only 7 (12.5%) were shown to possess known aminoglycoside-modifying enzymes; the remaining were presumably resistant by an incompletely understood mechanism often referred to as “impermeability.”

In silico Repurposing of Anticancer Drug (5-Fluorouracil) as an Antibacterial Agent against Klebsiella pneumoniae

2021 ◽  
Vol 18 ◽  
Author(s):  
Amey Sharma ◽  
Apoorva Rana ◽  
Lakshya Mangtani ◽  
Aakanksha Kalra ◽  
Ravi Ranjan Kumar Niraj
Keyword(s):  
Molecular Docking ◽  
Klebsiella Pneumoniae ◽  
Thymidylate Synthase ◽  
In Silico ◽  
Homology Modelling ◽  
Klebsiella Pneumonia ◽  
Drug Resistant ◽  
Vitro Analysis ◽  
In Vitro Analysis

Background: Infections caused by drug resistant microorganisms have been increasing worldwide thereby being one of the major causes of morbidity in the 21st century. Klebsiella pneumoniae is one such bacteria causing lung inflammation, lung injury and death. Emergence of hyper-virulent and drug resistant species such as ESBL and CRKP has made this microbe a serious and urgent threat. The pace of emergence of these species is outgrowing the development of novel drug and vaccine candidates thereby focusing on drug repurposing approach. Objective: 1. Homology Modelling of Thymidylate Synthase. 2. Verification of Modelled Structure. 3. Molecular Docking. 4. Molecular Dynamic Simulation of Docked Complex. 5. In vitro analysis of 5-FU activity against Klebsiella pneumonia. Method: The 3-D structure of Thymidylate Synthase was predicted using Swiss-Model server and validated by in silico approaches. - Determination protein-protein interactions using STRING database. - Molecular docking. - MD simulations of 5-FU with predicted structure of thymidylate synthase. - In vitro antimicrobial drug sensitivity assay at different concentrations. Result: Hydrogen bond was observed in Molecular Docking - Protein-ligand complex remains stable during simulation. - 5-FU shows antimicrobial activity against Klebsiella pneumonia during In vitro study. Conclusion: Both In silico as well as in vitro analysis have indicated that 5-FU can potentially be developed as an antimicrobial agent towards Klebsiella pneumonia

scholarly journals Novel Promoters Derived from Chinese Hamster Ovary Cells via In Silico and In Vitro Analysis

2019 ◽  
Vol 14 (11) ◽  
pp. 1900125 ◽  
Author(s):  
Ly N. Nguyen ◽  
Martina Baumann ◽  
Heena Dhiman ◽  
Nicolas Marx ◽  
Valerie Schmieder ◽  
...  
Keyword(s):  
Chinese Hamster Ovary ◽  
In Silico ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Ovary Cells ◽  
Vitro Analysis ◽  
In Vitro Analysis

scholarly journals Microbiology and Preclinical Review of Omadacycline

2019 ◽  
Vol 69 (Supplement_1) ◽  
pp. S6-S15 ◽  
Author(s):  
James A Karlowsky ◽  
Judith Steenbergen ◽  
George G Zhanel
Keyword(s):  
Legionella Pneumophila ◽  
Animal Studies ◽  
Action Spectrum ◽  
Binding Activity ◽  
Phase Iii ◽  
Phase Iii Clinical Trials ◽  
Clostridioides Difficile ◽  
Semisynthetic Derivative

AbstractOmadacycline is a novel aminomethylcycline antimicrobial and semisynthetic derivative of tetracycline. In vitro, omadacycline displays potent activity against gram-positive and many gram-negative bacteria, including methicillin-resistant Staphylococcus aureus, Streptococcus pneumoniae, β-hemolytic streptococci, vancomycin-resistant Enterococcus, and Enterobacteriaceae. Omadacycline is also active against atypical and anaerobic pathogens, including Legionella pneumophila, Mycoplasma spp., Ureaplasma spp., Bacteroides spp., and Clostridioides difficile. This review outlines the microbiology and preclinical studies of omadacycline, including its mechanism of action; spectrum of activity; protein binding; activity in the presence of surfactant, serum, normal, and pH-adjusted urine, or bacterial biofilms; postantibiotic effect; pharmacodynamic properties; and in vitro and in vivo efficacy. The results of in vitro and in vivo animal studies support the observations made in phase III clinical trials and the clinical development of omadacycline.

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