scholarly journals In silico Analysis of Plant Based Quorum Sensing Inhibitor against Chromobacterium violaceum CviR

Author(s):  
P. Nandini ◽  
P. Sankar Ganesh ◽  
A. S. Smiline Girija ◽  
J. Vijayashree Priyadharshini

Background: Chromobacterium violaceum (C. violaceum), a Gram-negative, facultative anaerobic, non-sporing coccobacillus has a quorum-sensing system consisting of CviI/CviR, a homologous gene. Quorum sensing (QS) is a mechanism of intercellular communication in bacteria that received substantial attention as an alternate strategy for combating bacterial resistance and the development of new anti-infective agents. Methods: DATA SET Information of photochemical from the natural source deposited as a machine readable format in PubChem database was utilized to retrieve the compound for the study. To study ligand - receptor interactions, docking paves way to accomplish the protein ligand interaction was docked through rigid docking CviR protein (PDB ID: 3QP5) was prepared and energy minimized to evaluate the best affinity among the complex. Results: The results showed that the Alpha.,2.Alpha.- Epoxy-1.Beta.- Methyl Cholesta-4,6- Dien-3-One had high affinity for CviR receptor protein and Alpha.,2.Alpha.- Epoxy-1.Beta.- Methyl Cholesta-4,6- Dien-3-One binds to the active site of CviR with binding energy of -9.6 kcal/mol. Conclusion: Overall study concluded that 1. Alpha., 2. Alpha.- Epoxy-1.Beta.-Methyl Cholesta-4,6-Dien-3-One with highest binding affinity for the CviR protein possessing strong inhibitory binding interaction. Hence, we concluded that 1.Alpha.,2.Alpha.-Epoxy-1.Beta.- Methyl Cholesta-4, 6-Dien-3-One good serves as potential an anti-quorum sensing molecule for treating C. violaceum infection.

2020 ◽  
Vol 2020 ◽  
pp. 1-18 ◽  
Author(s):  
José Luis Herrera-Arizmendi ◽  
Everardo Curiel-Quesada ◽  
José Correa-Basurto ◽  
Martiniano Bello ◽  
Alicia Reyes-Arellano

The increasing common occurrence of antibiotic-resistant bacteria has become an urgent public health issue. There are currently some infections without any effective treatment, which require new therapeutic strategies. An attractive alternative is the design of compounds capable of disrupting bacterial communication known as quorum sensing (QS). In Gram-negative bacteria, such communication is regulated by acyl-homoserine lactones (AHLs). Triggering of QS after bacteria have reached a high cell density allows them to proliferate before expressing virulence factors. Our group previously reported that hexyloxy phenylimidazoline (9) demonstrated 71% inhibitory activity of QS at 100 μM (IC50 = 90.9 μM) in Chromobacterium violaceum, a Gram-negative bacterium. The aim of the present study was to take 9 as a lead compound to design and synthesize three 2-imidazolines (13–15) and three 2-oxazolines (16–18), to be evaluated as quorum-sensing inhibitors on C. violaceum CV026. We were looking for compounds with a higher affinity towards the Cvi receptor of this bacterium and the ability to inhibit QS. The binding mode of the test compounds on the Cvi receptor was explored with docking studies and molecular dynamics. It was found that 8-pentyloxyphenyl-2-imidazoline (13) reduced the production of violacein (IC50 = 56.38 μM) without affecting bacterial growth, suggesting inhibition of quorum sensing. Indeed, compound 13 is apparently one of the best QS inhibitors known to date. Molecular docking revealed the affinity of compound 13 for the orthosteric site of N-hexanoyl homoserine lactone (C6-AHL) on the CviR protein. Ten amino acid residues in the active binding site of C6-AHL in the Cvi receptor interacted with 13, and 7 of these are the same as those interacting with AHL. Contrarily, 8-octyloxyphenyl-2-imidazoline (14), 8-decyloxyphenyl-2-imidazoline (15), and 9-decyloxyphenyl-2-oxazoline (18) bound only to an allosteric site and thus did not compete with C6-AHL for the orthosteric site.


2021 ◽  
Vol 16 (5) ◽  
pp. 1934578X2110150
Author(s):  
Gang Li ◽  
Wei Zhou ◽  
Xiurong Zhao ◽  
Ying Xie

The novel coronavirus, 2019-nCoV, has led to a major pandemic in 2020 and is responsible for more than 2.9 million officially recorded deaths worldwide. As well as synthetic anti-viral drugs, there is also a need to explore natural herbal remedies. The Traditional Chinese Medicines (TCMs) system has been used for thousands of years for the prevention, diagnosis, and treatment of several chronic diseases. In this paper, we performed an in silico molecular docking and interaction analysis of TCMs against SARS-CoV-2 receptor RNA-dependent RNA polymerase (RdRp). We obtained the 5 most effective plant compounds which had a better binding affinity towards the target receptor protein. These compounds areforsythoside A, rutin, ginkgolide C, icariside II, and nolinospiroside E. The top-ranked compound, based on docking score, was nolinospiroside, a glycoside found in Ophiopogon japonicas that has antioxidant properties. Protein-ligand interaction analysis discerned that nolinospiroside formed a strong bond between ARG 349 of the protein receptor and the carboxylate group of the ligand, forming a stable complex. Hence, nolinospiroside could be deployed as a lead compound against SARS-CoV-2 infection that can be further investigated for its potential benefits in curbing the viral infection.


Author(s):  
Nikayla Batohi ◽  
Shabir Ahmad Lone ◽  
Musa Marimani ◽  
Mohmmad Younus Wani ◽  
Abdullah Saad Al-Bogami ◽  
...  

2004 ◽  
Vol 72 (11) ◽  
pp. 6589-6596 ◽  
Author(s):  
Ricky L. Ulrich ◽  
David DeShazer ◽  
Harry B. Hines ◽  
Jeffrey A. Jeddeloh

ABSTRACT Numerous gram-negative bacterial pathogens regulate virulence factor expression by using a cell density mechanism termed quorum sensing (QS). An in silico analysis of the Burkholderia mallei ATCC 23344 genome revealed that it encodes at least two luxI and four luxR homologues. Using mass spectrometry, we showed that wild-type B. mallei produces the signaling molecules N-octanoyl-homoserine lactone and N-decanoyl-homoserine lactone. To determine if QS is involved in the virulence of B. mallei, we generated mutations in each putative luxIR homologue and tested the pathogenicities of the derivative strains in aerosol BALB/c mouse and intraperitoneal hamster models. Disruption of the B. mallei QS alleles, especially in RJ16 (bmaII) and RJ17 (bmaI3), which are luxI mutants, significantly reduced virulence, as indicated by the survival of mice who were aerosolized with 104 CFU (10 50% lethal doses [LD50s]). For the B. mallei transcriptional regulator mutants (luxR homologues), mutation of the bmaR5 allele resulted in the most pronounced decrease in virulence, with 100% of the challenged animals surviving a dose of 10 LD50s. Using a Syrian hamster intraperitoneal model of infection, we determined the LD50s for wild-type B. mallei and each QS mutant. An increase in the relative LD50 was found for RJ16 (bmaI1) (>967 CFU), RJ17 (bmaI3) (115 CFU), and RJ20 (bmaR5) (151 CFU) compared to wild-type B. mallei (<13 CFU). These findings demonstrate that B. mallei carries multiple luxIR homologues that either directly or indirectly regulate the biosynthesis of an essential virulence factor(s) that contributes to the pathogenicity of B. mallei in vivo.


2014 ◽  
Vol 73 (2) ◽  
pp. 1-4 ◽  
Author(s):  
Marielba Montes de Oca-Mejía ◽  
Israel Castillo-Juárez ◽  
Mariano Martínez-Vázquez ◽  
Marcos Soto-Hernandez ◽  
Rodolfo García-Contreras

mBio ◽  
2019 ◽  
Vol 10 (6) ◽  
Author(s):  
Jeremy T. Ritzert ◽  
George Minasov ◽  
Ryan Embry ◽  
Matthew J. Schipma ◽  
Karla J. F. Satchell

ABSTRACT Cyclic AMP (cAMP) receptor protein (Crp) is an important transcriptional regulator of Yersinia pestis. Expression of crp increases during pneumonic plague as the pathogen depletes glucose and forms large biofilms within lungs. To better understand control of Y. pestis Crp, we determined a 1.8-Å crystal structure of the protein-cAMP complex. We found that compared to Escherichia coli Crp, C helix amino acid substitutions in Y. pestis Crp did not impact the cAMP dependency of Crp to bind DNA promoters. To investigate Y. pestis Crp-regulated genes during plague pneumonia, we performed RNA sequencing on both wild-type and Δcrp mutant bacteria growing in planktonic and biofilm states in minimal media with glucose or glycerol. Y. pestis Crp was found to dramatically alter expression of hundreds of genes in a manner dependent upon carbon source and growth state. Gel shift assays confirmed direct regulation of the malT and ptsG promoters, and Crp was then linked to Y. pestis growth on maltose as a sole carbon source. Iron regulation genes ybtA and fyuA were found to be indirectly regulated by Crp. A new connection between carbon source and quorum sensing was revealed as Crp was found to regulate production of acyl-homoserine lactones (AHLs) through direct and indirect regulation of genes for AHL synthetases and receptors. AHLs were subsequently identified in the lungs of Y. pestis-infected mice when crp expression was highest in Y. pestis biofilms. Thus, in addition to the well-studied pla gene, other Crp-regulated genes likely have important functions during plague infection. IMPORTANCE Bacterial pathogens have evolved extensive signaling pathways to translate environmental signals into changes in gene expression. While Crp has long been appreciated for its role in regulating metabolism of carbon sources in many bacterial species, transcriptional profiling has revealed that this protein regulates many other aspects of bacterial physiology. The plague pathogen Y. pestis requires this global regulator to survive in blood, skin, and lungs. During disease progression, this organism adapts to changes within these niches. In addition to regulating genes for metabolism of nonglucose sugars, we found that Crp regulates genes for virulence, metal acquisition, and quorum sensing by direct or indirect mechanisms. Thus, this single transcriptional regulator, which responds to changes in available carbon sources, can regulate multiple critical behaviors for causing disease.


2020 ◽  
Vol 9 (4) ◽  
pp. 1569-1577

The quorum sensing (QS) mechanism has become a viable research strategy for the discovery of plant-derived anti-virulent agents to control drug-resistant bacteria. The increasing incidences of drug-resistant bacteria and the effort to curb it necessitate this study. We investigated the QS inhibitory potential of Centaurea praecox extracts on Chromobacterium violaceum (CV), antibacterial activity, and determination of chemical composition using GC-MS. C. praecox was subjected to sequential extraction using hexane (HEX), dichloromethane (DCM), ethyl acetate (EA), ethanol (ET), and aqueous (AQ) solvents. The extracts were subsequently evaluated for antibacterial activity using disc diffusion and QS violacein inhibition using spectrophotometry. The antibacterial effects of the extracts were moderate on gram-positive bacteria at 4 mg/mL in the order: HEX >EA >DCM >ET =AQ. However, the DCM extract demonstrated the most effective violacein inhibition of ≥80% at 0.3 mg/mL. QS violacein inhibitions were generally found to be concentration-dependent in the order: DCM >EA >HEX >ET =AQ with efficacies of ≥ 90% inhibition at ≥ 0.6 mg/mL. GC-MS analysis on the most potent DCM extract revealed N-vinylmethanimine, N-ethyl formamide, and propanamide among components identified. We concluded that C. praecox DCM extract contains bioactive chemicals as QS inhibitors and potential anti-virulent agents capable of combating the pathogenicity of drug-resistant bacteria in vivo.


2020 ◽  
Author(s):  
Ben Geoffrey A S ◽  
Akhil Sanker ◽  
Host Antony Davidd ◽  
Judith Gracia

Our work is composed of a python program for automatic data mining of PubChem database to collect data associated with the corona virus drug target replicase polyprotein 1ab (UniProt identifier : POC6X7 ) of data set involving active compounds, their activity value (IC50) and their chemical/molecular descriptors to run a machine learning based AutoQSAR algorithm on the data set to generate anti-corona viral drug leads. The machine learning based AutoQSAR algorithm involves feature selection, QSAR modelling, validation and prediction. The drug leads generated each time the program is run is reflective of the constantly growing PubChem database is an important dynamic feature of the program which facilitates fast and dynamic anti-corona viral drug lead generation reflective of the constantly growing PubChem database. The program prints out the top anti-corona viral drug leads after screening PubChem library which is over a billion compounds. The interaction of top drug lead compounds generated by the program and two corona viral drug target proteins, 3-Cystiene like Protease (3CLPro) and Papain like protease (PLpro) was studied and analysed using molecular docking tools. The compounds generated as drug leads by the program showed favourable interaction with the drug target proteins and thus we recommend the program for use in anti-corona viral compound drug lead generation as it helps reduce the complexity of virtual screening and ushers in an age of automatic ease in drug lead generation. The leads generated by the program can further be tested for drug potential through further In Silico, In Vitro and In Vivo testing <div><br></div><div><div>The program is hosted, maintained and supported at the GitHub repository link given below</div><div><br></div><div>https://github.com/bengeof/Drug-Discovery-P0C6X7</div></div><div><br></div>


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