154 results on '"Anand, Anbarasu"'
Search Results
2. Anti-bacterial compounds from Indian curry-leaf tree Murraya koenigii have potential to inhibit carbapenem-resistant Streptococcus pneumoniae
- Author
-
Soumya Basu, Balaji Veeraraghavan, and Anand Anbarasu
- Subjects
Pneumococci ,Meropenem ,Phytocompounds ,Pharmacokinetics ,Simulation ,Public aspects of medicine ,RA1-1270 - Abstract
Problems considered: Spike in the mortality rates due to pneumococcal infections post-COVID-19 has raised clinical concerns globally. β-lactam antibiotic-susceptibility in the causative organism, Streptococcus pneumoniae has been compromised due to non-synonymous single nucleotide polymorphisms (nsSNPs) in different penicillin-binding protein (PBP) targets. Carbapenem-resistant S. pneumoniae strains have further constricted the pharmacologically safe therapeutic options. Methods: In-house sequenced whole genomes of meropenem and cefotaxime resistant Indian and global isolates were used to retrieve parent and mutant proteins. Anti-bacterial phtytochemicals (ABPs) from Indian curry-leaf tree Murraya koenigii were identified using database-mining. ABPs were screeened based on pharmacokinetics, and toxicity profiles. Site-specific molecular docking studies revealed ABPs‘ affinity towards the targets as compared to control drug meropenem. Coarse-grained and normal-mode molecular dynamics simulation further asserted the interactive stability of the chosen compounds. Results: From the whole genomes (n = 28) of meropenem and cefotaxime resistant (MIC ≥0.5 μg/ml) Indian and global isolates, ∼50 nsSNPs in the active-site regions of PBP1A, PBP2B and PBP2X were identified. Based on pharmacological safety and high drug-likeliness, 10 ABPs were funnelled down from 226 ABPs in M. koenigii. A pyrano-carbazole alkaloid koenine was further prioritized as the most efficient candidate based on consistently high binding affinity (binding energies −7.7 to −8.9 kcal/mol), low inhibition constant (0.69–3.5 μM) and low structural fluctuations (
- Published
- 2024
- Full Text
- View/download PDF
3. Structure Elucidation and Interaction Dynamics of MefA-MsrD Efflux Proteins in Streptococcus pneumoniae: Impact on Macrolide Susceptibility
- Author
-
Sreeram Chandra Murthy Peela, Soumya Basu, Jyoti Sharma, Abdullah F. AlAsmari, Fawaz AlAsmari, Sultan Alalmaee, Sudha Ramaiah, Sujatha Sistla, Paul Livingstone, and Anand Anbarasu
- Subjects
Chemistry ,QD1-999 - Published
- 2023
- Full Text
- View/download PDF
4. Genomic investigation unveils colistin resistance mechanism in carbapenem-resistant Acinetobacter baumannii clinical isolates
- Author
-
Saranya Vijayakumar, Rayapadi G. Swetha, Yamuna Devi Bakthavatchalam, Karthick Vasudevan, Baby Abirami Shankar, Agilandeeswari Kirubananthan, Kamini Walia, Sudha Ramaiah, Indranil Biswas, Balaji Veeraraghavan, and Anand Anbarasu
- Subjects
Acinetobacter baumannii ,colistin ,resistance ,SNP ,lpx ,pmr ,Microbiology ,QR1-502 - Abstract
ABSTRACTColistin resistance in Acinetobacter baumannii is mediated by multiple mechanisms. Recently, mutations within pmrABC two-component system and overexpression of eptA gene due to upstream insertion of ISAba1 have been shown to play a major role. Thus, the aim of our study is to characterize colistin resistance mechanisms among the clinical isolates of A. baumannii in India. A total of 207 clinical isolates of A. baumannii collected from 2016 to 2019 were included in this study. Mutations within lipid A biosynthesis and pmrABC genes were characterized by whole-genome shotgun sequencing. Twenty-eight complete genomes were further characterized by hybrid assembly approach to study insertional inactivation of lpx genes and the association of ISAba1-eptA. Several single point mutations (SNPs), like M12I in pmrA, A138T and A444V in pmrB, and E117K in lpxD, were identified. We are the first to report two novel SNPs (T7I and V383I) in the pmrC gene. Among the five colistin-resistant A. baumannii isolates where complete genome was available, the analysis showed that three of the five isolates had ISAba1 insertion upstream of eptA. No mcr genes were identified among the isolates. We mapped the SNPs on the respective protein structures to understand the effect on the protein activity. We found that majority of the SNPs had little effect on the putative protein function; however, some SNPs might destabilize the local structure. Our study highlights the diversity of colistin resistance mechanisms occurring in A. baumannii, and ISAba1-driven eptA overexpression is responsible for colistin resistance among the Indian isolates.IMPORTANCEAcinetobacter baumannii is a Gram-negative, emerging and opportunistic bacterial pathogen that is often associated with a wide range of nosocomial infections. The treatment of these infections is hindered by increase in the occurrence of A. baumannii strains that are resistant to most of the existing antibiotics. The current drug of choice to treat the infection caused by A. baumannii is colistin, but unfortunately, the bacteria started to show resistance to the last-resort antibiotic. The loss of lipopolysaccharides and mutations in lipid A biosynthesis genes are the main reasons for the colistin resistance. The present study characterized 207 A. baumannii clinical isolates and constructed complete genomes of 28 isolates to recognize the mechanisms of colistin resistance. We showed the mutations in the colistin-resistant variants within genes essential for lipid A biosynthesis and that cause these isolates to lose the ability to produce lipopolysaccharides.
- Published
- 2024
- Full Text
- View/download PDF
5. Epidemiology of Multidrug Resistance among Salmonella enterica serovars typhi and paratyphi A at a Tertiary Pediatric Hospital in India Over a Decade; In-silico Approach to Elucidate the Molecular Mechanism of Quinolone Resistance
- Author
-
Anand Manoharan, Dipjyoti Dey, Sulochana Putlibai, Sudha Ramaiah, Anand Anbarasu, and S. Balasubramanian
- Subjects
Enteric fever ,S. typhi ,S. paratyphi A ,Molecular docking ,Gyrase A ,Fluoroquinolone ,Infectious and parasitic diseases ,RC109-216 - Abstract
Background: Enteric fever caused by Salmonella enterica serovar typhi and Salmonella enterica serovar paratyphi A remains one of the most common causes of community-acquired bloodstream infection among children in India. Multidrug resistance is emerging and is a cause of concern as it affects the choice of treatment in enteric fever. Method: In this study, a 10-year analysis of resistance patterns was done along with in-silico homology modeling and molecular docking to understand the commonly occurring quinolone resistance. Results: A total of 1010 cases of blood culture–confirmed enteric fevers (S. typhi n=849; S. paratyphi A n=161) were recorded at the study hospital during the period from 2011-2020. Multidrug resistance among cases of S. typhi was 2.12 %, whereas it was completely absent among cases of S. paratyphi A. Fluoroquinolone resistance was high (>95%) throughout the study period. Resistance to ampicillin, chloramphenicol and co-trimoxacole was low (
- Published
- 2022
- Full Text
- View/download PDF
6. Network metrics, structural dynamics and density functional theory calculations identified a novel Ursodeoxycholic Acid derivative against therapeutic target Parkin for Parkinson's disease
- Author
-
Aniket Naha, Sanjukta Banerjee, Reetika Debroy, Soumya Basu, Gayathri Ashok, P. Priyamvada, Hithesh Kumar, A.R. Preethi, Harpreet Singh, Anand Anbarasu, and Sudha Ramaiah
- Subjects
Biomarker ,Docking ,Ligand optimization ,Neurodegenerative disorder ,Simulation ,Systems biology ,Biotechnology ,TP248.13-248.65 - Abstract
Parkinson's disease (PD) has been designated as one of the priority neurodegenerative disorders worldwide. Although diagnostic biomarkers have been identified, early onset detection and targeted therapy are still limited. An integrated systems and structural biology approach were adopted to identify therapeutic targets for PD. From a set of 49 PD associated genes, a densely connected interactome was constructed. Based on centrality indices, degree of interaction and functional enrichments, LRRK2, PARK2, PARK7, PINK1 and SNCA were identified as the hub-genes. PARK2 (Parkin) was finalized as a potent theranostic candidate marker due to its strong association (score > 0.99) with α-synuclein (SNCA), which directly regulates PD progression. Besides, modeling and validation of Parkin structure, an extensive virtual-screening revealed small (commercially available) inhibitors against Parkin. Molecule-258 (ZINC5022267) was selected as a potent candidate based on pharmacokinetic profiles, Density Functional Theory (DFT) energy calculations (ΔE = 6.93 eV) and high binding affinity (Binding energy = -6.57 ± 0.1 kcal/mol; Inhibition constant = 15.35 µM) against Parkin. Molecular dynamics simulation of protein-inhibitor complexes further strengthened the therapeutic propositions with stable trajectories (low structural fluctuations), hydrogen bonding patterns and interactive energies (>0kJ/mol). Our study encourages experimental validations of the novel drug candidate to prevent the auto-inhibition of Parkin mediated ubiquitination in PD.
- Published
- 2022
- Full Text
- View/download PDF
7. Impact of the COVID-19 pandemic on routine vaccine landscape: A global perspective
- Author
-
Soumya Basu, Gayathri Ashok, Reetika Debroy, Sudha Ramaiah, Paul Livingstone, and Anand Anbarasu
- Subjects
covid-19 ,vaccines ,disruption ,routine immunization ,Immunologic diseases. Allergy ,RC581-607 ,Therapeutics. Pharmacology ,RM1-950 - Abstract
The coronavirus disease (COVID-19) threat is subsiding through extensive vaccination worldwide. However, the pandemic imposed major disruptions in global immunization programs and has aggravated the risks of vaccine-preventable disease (VPD) outbreaks. Particularly, lower-middle-income regions with minimal vaccine coverage and circulating vaccine-derived viral strains, such as polio, suffered additional burden of accumulated zero-dose children, further making them vulnerable to VPDs. However, there is no compilation of routine immunization disruptions and recovery prospects. There is a noticeable change in the routine vaccination coverage across different phases of the pandemic in six distinct global regions. We have summarized the impact of COVID-19 on routine global vaccination programs and also identified the prospects of routine immunization to combat COVID-like outbreaks.
- Published
- 2023
- Full Text
- View/download PDF
8. Datasets comprising the quality validations of simulated protein-ligand complexes and SYBYL docking scores of bioactive natural compounds as inhibitors of Mycobacterium tuberculosis protein-targets
- Author
-
Sravan Kumar Miryala, Soumya Basu, Aniket Naha, Reetika Debroy, Sudha Ramaiah, Anand Anbarasu, and Saravanan Natarajan
- Subjects
Docking ,Simulation ,Natural compounds ,Tuberculosis ,Therapeutics ,Computer applications to medicine. Medical informatics ,R858-859.7 ,Science (General) ,Q1-390 - Abstract
Docking scores and simulation parameters to study the potency of natural compounds against protein targets in Mycobacterium tuberculosis (Mtb) were retrieved through molecular docking and in-silico structural investigation. The molecular docking datasets comprised 15 natural compounds, seven conventional anti-tuberculosis (anti-TB) drugs and their seven corresponding Mtb target proteins. Mtb protein targets were actively involved in translation mechanism, nucleic acid metabolism and membrane integrity. Standard structural screening and stereochemical optimizations were adopted to generate the 3D protein structures and their corresponding ligands prior to molecular docking. Force-field integration and energy minimization were further employed to obtain the proteins in their ideal geometry. Surflex-dock algorithm using Hammerhead scoring functions were used to finally produce the docking scores between each protein and the corresponding ligand(s). The best-docked complexes selected for simulation studies were subjected to topology adjustments, charge neutralizations, solvation and equilibrations (temperature, volume and pressure). The protein-ligand complexes and molecular dynamics parameter files have been provided. The trajectories of the simulated parameters such as density, pressure and temperature were generated with integrated tools of the simulation suite. The datasets can be useful to computational and molecular medicine researchers to find therapeutic leads relevant to the chemical behaviours of a specific class of compounds against biological systems. Structural parameters and energy functions provided a set of standard values that can be utilised to design simulation experiments regarding similar macromolecular interactions.
- Published
- 2022
- Full Text
- View/download PDF
9. Transcriptional expression of secondary resistance genes ccdB and repA2 is enhanced in presence of cephalosporin and carbapenem in Escherichia coli
- Author
-
Somorita Baishya, Chandrayee Deshamukhya, Jayalaxmi Wangkheimayum, Bhaskar Jyoti Das, Anand Anbarasu, Anupam Das Talukdar, Amitabha Bhattacharjee, and Manabendra Dutta Choudhury
- Subjects
repA2 ,ccdB ,Secondary resistance ,Cephalosporin ,Carabapenem ,Escherichia coli ,Microbiology ,QR1-502 - Abstract
Abstract Background The issue of carbapenem resistance in E.coli is very concerning and it is speculated that cumulative effect of both primary resistance genes and secondary resistance genes that act as helper to the primary resistance genes are the reason behind their aggravation. Therefore, here we attempted to find the role of two secondary resistance genes (SRG) ccdB and repA2 in carbapenem resistance in E. coli (CRE). In this context influential genes belonging to secondary resistome that act as helper to the primary resistance genes like bla NDM and bla CTX-M in aggravating β-lactam resistance were selected from an earlier reported in silico study. Transcriptional expression of the selected genes in clinical isolates of E.coli that were discretely harboring bla NDM-1, bla NDM-4, bla NDM-5, bla NDM-7 and bla CTX-M-15 with and without carbapenem and cephalosporin stress (2 μg/ml) was determined by real time PCR. Cured mutants sets that were lacking (i) primary resistance genes, (ii) secondary resistance genes and (iii) both primary and secondary resistance genes were prepared by SDS treatment. These sets were then subjected to antibiotic susceptibility testing by Kirby Bauer disc diffusion method. Results Out of the 21 genes reported in the in silico study, 2 genes viz. repA2 and ccdB were selected for transcriptional expression analysis. repA2, coding replication regulatory protein, was downregulated in response to carbapenems and cephalosporins. ccdB, coding for plasmid maintenance protein, was also downregulated in response to carbapenems except imipenem and cephalosporins. Following plasmid elimination assay increase in diameter of zone of inhibition under stress of both antibiotics was observed as compared to uncured control hinting at the reversion of antibiotic susceptibility by the-then resistant bacteria. Conclusion SRGs repA2 and ccdB help sustenance of bla NDM and bla CTX-M under carbapenem and cephalosporin stress.
- Published
- 2021
- Full Text
- View/download PDF
10. Emergence of Meropenem Resistance Among Cefotaxime Non-susceptible Streptococcus pneumoniae: Evidence and Challenges
- Author
-
Rosemol Varghese, Soumya Basu, Ayyanraj Neeravi, Agilakumari Pragasam, V. Aravind, Richa Gupta, Angel Miraclin, Sudha Ramaiah, Anand Anbarasu, and Balaji Veeraraghavan
- Subjects
S. pneumoniae ,penicillin-binding protein ,cefotaxime ,meropenem ,stability ,Microbiology ,QR1-502 - Abstract
The principal causative agent of acute bacterial meningitis (ABM) in children and the elderly is Streptococcus pneumoniae, with a widespread increase in penicillin resistance. Resistance is due to non-synonymous single-nucleotide polymorphisms (nsSNPs) that alter the penicillin-binding proteins (PBPs), the targets for all β-lactam drugs. Hence, resistance against one β-lactam antibiotic may positively select another. Since meropenem is an alternative to cefotaxime in meningeal infections, we aim to identify whether nsSNPs in the PBPs causing penicillin and cefotaxime resistance can decrease the pneumococcal susceptibility to meropenem. Comparison of the nsSNPs in the PBPs between the cefotaxime-resistant Indian (n = 33) and global isolates (n = 28) revealed that nsSNPs in PBP1A alone elevated meropenem minimal inhibitory concentrations (MICs) to 0.12 μg/ml, and nsSNPs in both PBP2X and 2B combined with PBP1A increases MIC to ≥ 0.25 μg/ml. Molecular docking confirmed the decrease in the PBP drug binding affinity due to the nsSNPs, thereby increasing the inhibition potential and the MIC values, leading to resistance. Structural dynamics and thermodynamic stability pattern in PBPs as a result of mutations further depicted that the accumulation of certain nsSNPs in the functional domains reduced the drug affinity without majorly affecting the overall stability of the proteins. Restricting meropenem usage and promoting combination therapy with antibiotics having non-PBPs as targets to treat cefotaxime non-susceptible S. pneumoniae meningitis can prevent the selection of β-lactam resistance.
- Published
- 2022
- Full Text
- View/download PDF
11. Aerobactin Seems To Be a Promising Marker Compared With Unstable RmpA2 for the Identification of Hypervirulent Carbapenem-Resistant Klebsiella pneumoniae: In Silico and In Vitro Evidence
- Author
-
Chaitra Shankar, Soumya Basu, Binesh Lal, Sathiya Shanmugam, Karthick Vasudevan, Purva Mathur, Sudha Ramaiah, Anand Anbarasu, and Balaji Veeraraghavan
- Subjects
Klebsiella pneumoniae ,hypervirulent ,aerobactin ,rmpA2 ,carbapenem resistance ,OXA-232 ,Microbiology ,QR1-502 - Abstract
BackgroundThe incidence of hypervirulent (hv) carbapenem-resistant (CR) Klebsiella pneumoniae (Kp) is increasing globally among various clones and is also responsible for nosocomial infections. The CR-hvKp is formed by the uptake of a virulence plasmid by endemic high-risk clones or by the uptake of plasmids carrying antimicrobial resistance genes by the virulent clones. Here, we describe CR-hvKp from India belonging to high-risk clones that have acquired a virulence plasmid and are phenotypically unidentified due to lack of hypermucoviscosity.MethodsTwenty-seven CRKp isolates were identified to possess rmpA2 by whole-genome sequencing; and resistance and virulence determinants were characterized. By in silico protein modeling (and validation), protein backbone stability analysis, and coarse dynamics study, the fitness of RmpA, RmpA2, and aerobactin-associated proteins-IucA and IutA, were determined to establish a reliable marker for clinical identification of CR-hvKp.ResultsThe CR-hvKp belonged to multidrug-resistant (MDR) high-risk clones such as CG11, CG43, ST15, and ST231 and carried OXA-232 as the predominant carbapenemase followed by NDM. The virulence plasmid belonged to IncHI1B replicon type and carried frameshifted and truncated rmpA and rmpA2. This resulted in a lack of hypermucoviscous phenotype. However, functional aerobactin was expressed in all high-risk clones. In silico analysis portrayed that IucA and IutA were more stable than classical RmpA. Furthermore, IucA and IutA had lower conformational fluctuations in the functional domains than the non-functional RmpA2, which increases the fitness cost of the latter for its maintenance and expression among CR-hvKp. Hence, RmpA and RmpA2 are likely to be lost among CR-hvKp owing to the increased fitness cost while coding for essential antimicrobial resistance and virulence factors.ConclusionIncreasing incidence of convergence of AMR and virulence is observed among K. pneumoniae globally, which warrants the need for reliable markers for identifying CR-hvKp. The presence of non-functional RmpA2 among high-risk clones highlights the significance of molecular identification of CR-hvKp. The negative string test due to non-functional RmpA2 among CR-hvKp isolates challenges phenotypic screening and faster identification of this pathotype. This can potentially be counteracted by projecting aerobactin as a stable, constitutively expressed, and functional marker for rapidly evolving CR-hvKp.
- Published
- 2021
- Full Text
- View/download PDF
12. Multi-Epitope Vaccine for Monkeypox Using Pan-Genome and Reverse Vaccinology Approaches
- Author
-
Rayapadi G. Swetha, Soumya Basu, Sudha Ramaiah, and Anand Anbarasu
- Subjects
monkeypox ,vaccine ,epitope ,pan-genome ,immunoinformatics ,virus ,Microbiology ,QR1-502 - Abstract
Outbreaks of monkeypox virus infections have imposed major health concerns worldwide, with high morbidity threats to children and immunocompromised adults. Although repurposed drugs and vaccines are being used to curb the disease, the evolving traits of the virus, exhibiting considerable genetic dynamicity, challenge the limits of a targeted treatment. A pan-genome-based reverse vaccinology approach can provide fast and efficient solutions to resolve persistent inconveniences in experimental vaccine design during an outbreak-exigency. The approach encompassed screening of available monkeypox whole genomes (n = 910) to identify viral targets. From 102 screened viral targets, viral proteins L5L, A28, and L5 were finalized based on their location, solubility, and antigenicity. The potential T-cell and B-cell epitopes were extracted from the proteins using immunoinformatics tools and algorithms. Multiple vaccine constructs were designed by combining the epitopes. Based on immunological properties, chemical stability, and structural quality, a novel multi-epitopic vaccine construct, V4, was finalized. Flexible-docking and coarse-dynamics simulation portrayed that the V4 had high binding affinity towards human HLA-proteins (binding energy < −15.0 kcal/mol) with low conformational fluctuations (
- Published
- 2022
- Full Text
- View/download PDF
13. Bioactive phytocompounds against specific target proteins of Borrelia recurrentis responsible for louse‐borne relapsing fever: Genomics and structural bioinformatics evidence
- Author
-
Soumya Basu, Reetika Debroy, Hithesh Kumar, Harpreet Singh, Sudha Ramaiah, and Anand Anbarasu
- Subjects
General Veterinary ,Insect Science ,Parasitology ,Ecology, Evolution, Behavior and Systematics - Abstract
Louse-borne relapsing fever (LBRF) with high untreated mortality caused by spirochete Borrelia recurrentis is predominantly endemic to Sub-Saharan Africa and has re-emerged in parts of Eastern Europe, Asia and Latin America due to population migrations. Despite subtractive evolution of lice-borne pathogenic Borrelia spp. from tick-borne species, there has been no comprehensive report on conservation of protein targets across tick and lice-borne pathogenic Borrelia nor exploration of phytocompounds that are toxic to tick against lice. From the 19 available whole genomes including B. recurrentis, B. burgdorferi, B. hermsii, B. parkeri and B. miyamotoi, conservation of seven drug targets (80% domain identity) viz. 30 S ribosomal subunit proteins (RSP) S3, S7, S8, S14, S19, penicillin-binding protein-2 and 50 S RSP L16 were deciphered through multiple sequence alignments. Twelve phytocompounds (hydroxy-tyrosol, baicalein, cis-2-decanoic acid, morin, oenin, rosemarinic acid, kaempferol, piceatannol, rottlerin, luteolin, fisetin and monolaurin) previously explored against Lyme disease spirochete B. burgdorferi when targeted against LBRF-causing B. recurrentis protein targets revealed high multi-target affinity (2%-20% higher than conventional antibiotics) through molecular docking. However, based on high binding affinity against all target proteins, stable coarse-grained dynamics (fluctuations1 Å) and safe pharmacological profile, luteolin was prioritized. The study encourages experimental evaluation of the potent phytocompounds and similar protocols for investigating other emerging vector-borne diseases.
- Published
- 2022
14. Vaccine repurposing approach for preventing COVID 19: can MMR vaccines reduce morbidity and mortality?
- Author
-
Anand Anbarasu, Sudha Ramaiah, and Paul Livingstone
- Subjects
covid-19 ,sars-cov-2 ,children ,innate immunity ,mmr vaccine ,prophylaxis ,Immunologic diseases. Allergy ,RC581-607 ,Therapeutics. Pharmacology ,RM1-950 - Abstract
The coronavirus disease (COVID-19) is resulting in millions of infected individuals with several hundred thousands dead throughout the world. Amidst all the havoc, one interesting observation in the present COVID-19 pandemic is the negligible symptoms in the young; particularly children below 10 years of age. We assume the extensive pediatric vaccination with MMR vaccines followed globally could have resulted in innate immune responses, e.g., induction of interferons (IFNs) and activated natural killer (NK) cells, thereby offering natural immunity against SARS-CoV-2 in the young population. Possible cross-protective innate immunity offered by MMR vaccination prompted us to suggest repurposing MMR vaccination for immuno-prophylaxis against COVID-19.
- Published
- 2020
- Full Text
- View/download PDF
15. Cancer-biomarkers associated with sex hormone receptors and recent therapeutic advancements: a comprehensive review
- Author
-
Suvitha Anbarasu and Anand Anbarasu
- Subjects
Cancer Research ,Oncology ,Hematology ,General Medicine - Published
- 2023
16. Designing Anti-Microbial Peptides Against Major β-Lactamase Enzymes in Clinically Important Gram-Negative Bacterial Pathogens: An In-Silico Study
- Author
-
Soumya Basu, Sahil Mandar Joshi, Sudha Ramaiah, and Anand Anbarasu
- Subjects
Molecular Docking Simulation ,Gram-Negative Bacteria ,Molecular Medicine ,Microbial Sensitivity Tests ,Peptides ,Molecular Biology ,Microbiology ,beta-Lactamases ,Anti-Bacterial Agents - Abstract
Anti-microbial resistance (AMR) creating healthcare concerns worldwide requires ardent exploration of therapeutic alternatives. Although anti-microbial peptides (AMP) are popular for broad-spectrum activity, recent evidence of increasing resistance to membrane-acting AMPs by ESKAPE pathogens has compelled us to design novel AMPs as therapeutic candidates. A library of 60 AMPs comprising natural AMPs and their mutants was constructed through in-silico methods. After physico-chemical property evaluations, each peptide in the library was subjected to flexible molecular docking against four major β-lactamases in Gram-negative ESKAPE pathogens. Among the potent AMP mutants, a Lactoferricin B-Mutant (M4) possessed uniformly high affinity with SHV1, OXA48, NDM1, and AmpC having energies -842.0Kcal/mol, -774.8Kcal/mol, -1103.3Kcal/mol, and -858.8Kcal/mol respectively. Coarse-grained clustering and flexibility analysis further accounted for the residue-level stable configurations of the protein-peptide complexes with high affinity. Highest affinity of Lactoferricin B_M4 was found with NDM1 due to H-bonds, salt-bridges, and hydrophobic interactions with the metallo-β-lactamase domain including crucial active-site residue Asp124. Molecular dynamics simulation further confirmed the stability of Lactoferricin B_M4-NDM1 complex having low residue-level root-mean square deviations (RMSD), atomic-level fluctuations, and radius of gyration (Rg). The study encourages experimental validations and similar methods to identify potential AMPs against drug-resistant pathogens.
- Published
- 2022
17. Systems biology tools for the identification of potential drug targets and biological markers effective for cancer therapeutics
- Author
-
Gayathri Ashok, P. Priyamvada, Sravan Kumar Miryala, Anand Anbarasu, and Sudha Ramaiah
- Published
- 2023
18. Integrated computational approaches to aid precision medicine for cancer therapy: Present scenario and future prospects
- Author
-
Hithesh Kumar, Sravan Kumar Miryala, Anand Anbarasu, and Sudha Ramaiah
- Published
- 2023
19. Genome sequencing and molecular characterisation of XDR Acinetobacter baumannii reveal complexities in resistance: Novel combination of sulbactam–durlobactam holds promise for therapeutic intervention
- Author
-
Balaji Veeraraghavan, Aniket Naha, Sudha Ramaiah, Baby Abirami Shankar, Saranya Vijayakumar, Anand Anbarasu, Binesh Lal, and Suriya Chandran
- Subjects
clone (Java method) ,Acinetobacter baumannii ,Nonsynonymous substitution ,Avibactam ,Aztreonam ,Biochemistry ,chemistry.chemical_compound ,Drug Resistance, Multiple, Bacterial ,medicine ,Humans ,Molecular Biology ,Gene ,Whole genome sequencing ,Strain (chemistry) ,biology ,Chemistry ,Cell Biology ,Sulbactam ,biology.organism_classification ,Molecular biology ,Neoplasm Proteins ,Drug Combinations ,Mutation ,Multilocus sequence typing ,Azabicyclo Compounds ,Acinetobacter Infections ,medicine.drug - Abstract
Acinetobacter baumannii is an emerging nosocomial strain expressing extensive drug resistance (XDR). Whole-genome sequencing and molecular characterisation analysis revealed the presence of carbapenemase in 92.86% of studied Indian isolates having blaOXA-51, blaOXA-23, blaOXA-58, and blaNDM genes, with a few evidences of dual carbapenemase genes. As per the MLST scheme, IC2Oxf/CC2Pas was the predominant clone, with 57.14% isolates belonging to this lineage. The presence of β-lactamases has rendered sulbactam (SUL) resistance (MIC: 16-256µg/ml) in all the studied isolates. The efficacy of novel durlobactam (DUR) in inhibiting β-lactamases and PBP2 was assessed through in-silico inter-molecular interaction analysis. Several non-synonymous single nucleotide polymorphisms (nsSNPs) were identified in PBP2 (G264S, I108V, S259T) and PBP3 (A515V, T526S) sequences. Minimal variations were recorded in the protein-backbone dynamics in active-site motifs of wild-type (WT) and mutants (MT), which correlated with the negligible binding energy fluctuations for PBP3-SUL (−5.85±0.04Kcal/mol) and PBP2-DUR (−5.16±0.66Kcal/mol) complexes. Furthermore, stronger binding affinities and low inhibition constants were noted in DUR complexed with OXA23 (−7.36Kcal/mol; 4.01µM), OXA58 (−6.44Kcal/mol; 19.07µM) and NDM (−6.82Kcal/mol; 10.01µM) when compared with conventional drugs avibactam and aztreonam. Stable interaction profiles of DUR, can possibly restore SUL activity against both PBP3WT and PBP3MTs. The study establishes the efficacy of novel SUL-DUR combination as a successful treatment strategy to combat emerging XDR strains.
- Published
- 2021
20. Antimicrobial Peptides as Immunomodulators and Antimycobacterial Agents to Combat Mycobacterium tuberculosis: a Critical Review
- Author
-
Preethi A. R. and Anand Anbarasu
- Subjects
Molecular Medicine ,Molecular Biology ,Microbiology - Abstract
Tuberculosis (TB) is a devastating disease foisting a significantly high morbidity, prepotent in low- and middle-income developing countries. Evolution of drug resistance among Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis, has made the TB treatment more complicated. The protracted nature of present TB treatment, persistent and tolerant Mtb populations, interaction with antiretroviral therapy and existing toxicity concerned with conventional anti-TB drugs are the four major challenges inflicted with emergence of drug-resistant mycobacterial strains, and the standard medications are unable to combat these strains. These factors emphasize an exigency to develop new drugs to overcome these barriers in current TB therapy. With this regard, antimycobacterial peptides derived from various sources such as human cells, bacterial sources, mycobacteriophages, fungal, plant and animal sources could be considered as antituberculosis leads as most of these peptides are associated with dual advantages of having both bactericidal activity towards Mtb as well as immuno-regulatory property. Some of the peptides possess the additional advantage of interacting synergistically with antituberculosis medications too, thereby increasing their efficiency, underscoring the vigour of antimicrobial peptides (AMPs) as best possible alternative therapeutic candidates or adjuvants in TB treatment. Albeit the beneficiary features of these peptides, few obstacles allied with them like cytotoxicity and proteolytic degradation are matter of concerns too. In this review, we have focused on structural hallmarks, targeting mechanisms and specific structural aspects contributing to antimycobacterial activity and discovered natural and synthetic antimycobacterial peptides along with their sources, anti-TB, immuno-regulatory properties, merits and demerits and possible delivery methods of AMPs.
- Published
- 2022
21. In Silico Approaches for Understanding Antimicrobial Resistance in Bacterial Pathogens
- Author
-
Sudha Ramaiah, Sravan Kumar Miryala, C.K. Hithesh Kumar, and Anand Anbarasu
- Published
- 2022
22. Green synthesis and characterization of water soluble nanocarnosine: A prospective drug delivery system
- Author
-
Nagarajan Usharani, Aniket Naha, Anand Anbarasu, Sudha Ramaiah, Swarna V Kanth, and Saravanan Natarajan
- Subjects
General Materials Science - Published
- 2023
23. A comprehensive review on genomics, systems biology and structural biology approaches for combating antimicrobial resistance in ESKAPE pathogens: computational tools and recent advancements
- Author
-
P. Priyamvada, Reetika Debroy, Anand Anbarasu, and Sudha Ramaiah
- Subjects
Physiology ,Systems Biology ,Drug Resistance, Bacterial ,Computational Biology ,Genomics ,General Medicine ,Applied Microbiology and Biotechnology ,Anti-Bacterial Agents ,Biotechnology - Abstract
In recent decades, antimicrobial resistance has been augmented as a global concern to public health owing to the global spread of multidrug-resistant strains from different ESKAPE pathogens. This alarming trend and the lack of new antibiotics with novel modes of action in the pipeline necessitate the development of non-antibiotic ways to treat illnesses caused by these isolates. In molecular biology, computational approaches have become crucial tools, particularly in one of the most challenging areas of multidrug resistance. The rapid advancements in bioinformatics have led to a plethora of computational approaches involving genomics, systems biology, and structural biology currently gaining momentum among molecular biologists since they can be useful and provide valuable information on the complex mechanisms of AMR research in ESKAPE pathogens. These computational approaches would be helpful in elucidating the AMR mechanisms, identifying important hub genes/proteins, and their promising targets together with their interactions with important drug targets, which is a crucial step in drug discovery. Therefore, the present review aims to provide holistic information on currently employed bioinformatic tools and their application in the discovery of multifunctional novel therapeutic drugs to combat the current problem of AMR in ESKAPE pathogens. The review also summarizes the recent advancement in the AMR research in ESKAPE pathogens utilizing the in silico approaches.
- Published
- 2022
24. Genomics and structural insight into the masking of gentamicin-resistance in clinical Burkholderia pseudomallei strain VB29710 from India
- Author
-
Yamuna Devi Bakthavatchalam, Soumya Basu, Abirami Shankar, Sudha Ramaiah, Anand Anbarasu, and Balaji Veeraraghavan
- Subjects
Microbiology (medical) ,Infectious Diseases ,General Medicine - Abstract
The present study reported a rare gentamicin-susceptible β-lactamase (PenA, OXA-57) expressing clinical Burkholderia pseudomallei isolate VB29710 from India. Whole-genome sequencing and structural analyses revealed the insertion of R962 and L963 into AmrB, the transmembrane-protein of the AmrAB-OprA efflux-pump that affected aminoglycoside-efflux through local alterations in backbone conformation.
- Published
- 2023
25. Systems biology approach to understand the interplay between Bacillus anthracis and human host genes that leads to CVDs
- Author
-
Shabduli Shinde, Sravan Kumar Miryala, Anand Anbarasu, and Sudha Ramaiah
- Subjects
Infectious Diseases ,Microbiology - Published
- 2023
26. Preclinical Evaluation of Sol-gel Synthesized Modulated 45S5-Bioglass Based Biodegradable Bone Graft Intended for Alveolar Bone Regeneration
- Author
-
Anand Manoharan, Nebu George Thomas, and Anand Anbarasu
- Subjects
Biomaterials ,Materials science ,Regeneration (biology) ,Medicine (miscellaneous) ,Biomaterial ,Orthopedics and Sports Medicine ,Cell Biology ,General Dentistry ,Biochemistry ,Dental alveolus ,Sol-gel ,Biomedical engineering - Published
- 2021
27. Organ-specific host differential gene expression analysis in systemic candidiasis: A systems biology approach
- Author
-
Sravan Kumar Miryala, Anand Anbarasu, and Sudha Ramaiah
- Subjects
Infectious Diseases ,Systems Biology ,Candida albicans ,Candidiasis ,COVID-19 ,Gene Expression ,Humans ,Microbiology - Abstract
Patients admitted to the hospital with coronavirus disease (COVID-19) are at risk for acquiring mycotic infections in particular Candidemia. Candida albicans (C. albicans) constitutes an important component of the human mycobiome and the most common cause of invasive fungal infections. Invasive yeast infections are gaining interest among the scientific community as a consequence of complications associated with severe COVID-19 infections. Early identification and surveillance for Candida infections is critical for decreasing the COVID-19 mortality. Our current study attempted to understand the molecular-level interactions between the human genes in different organs during systematic candidiasis. Our research findings have shed light on the molecular events that occur during Candidiasis in organs such as the kidney, liver, and spleen. The differentially expressed genes (up and down-regulated) in each organ will aid in designing organ-specific therapeutic protocols for systemic candidiasis. We observed organ-specific immune responses such as the development of the acute phase response in the liver; TGF-pathway and genes involved in lymphocyte activation, and leukocyte proliferation in the kidney. We have also observed that in the kidney, filament production, up-regulation of iron acquisition mechanisms, and metabolic adaptability are aided by the late initiation of innate defense mechanisms, which is likely related to the low number of resident immune cells and the sluggish recruitment of new effector cells. Our findings point to major pathways that play essential roles in specific organs during systemic candidiasis. The hub genes discovered in the study can be used to develop novel drugs for clinical management of Candidiasis.
- Published
- 2022
28. Emergence of sulphonamide resistance in azithromycin-resistant pediatric strains of Salmonella Typhi and Paratyphi A: A genomics insight
- Author
-
Hithesh Kumar, Anand Manoharan, Anand Anbarasu, and Sudha Ramaiah
- Subjects
Sulfanilamide ,Salmonella paratyphi A ,Drug Resistance, Bacterial ,Genetics ,Humans ,General Medicine ,Genomics ,Microbial Sensitivity Tests ,Salmonella typhi ,Azithromycin ,Typhoid Fever ,Child ,Anti-Bacterial Agents - Abstract
Whole genome sequences of Salmonella enterica subspecies enterica serovar Typhi (S. Typhi) and Salmonella enterica subspecies enterica serovar Paratyphi A (S. Paratyphi A) from pediatric settings were used to assess the emerging Antimicrobial Resistance (AMR). The high throughput sequences of twenty pediatric clinical isolates of S. Typhi and S. Paratyphi A were retrieved and were screened for prevalent Antimicrobial Resistance Genes (ARGs) and Virulent Factors (VF). The resistance data was compared with the reference strains of S. Typhi and S. Paratyphi A. AMR studies identified sul1, sul2, dfrA7, tem-1, AH(6)-Id and APH(3″)-Ib as common ARGs. VFs were identified to understand the level of pathogenicity. The most prevalent AMR genes in the sequenced genomes were detected in phenotypically azithromycin-resistant S. Typhi. Correlation with the global genomes projected a trend of concurrent resistance to macrolides, β lactams, fluoroquinolones (FQs), tetracyclines, ansamycins, and aminoglycosides. Traces of sulphonamide-resistance were observed indicating the emergence of a currently non-prevalent S. Typhi resistance that could be a future threat. Hence new antibiotic regimen to treat azithromycin-resistant S. Typhi should be formulated by avoiding the risks of aggravating sulphonamide resistance. The identified ARGs in genomes from paediatric isolates will aid future studies to design anti-bacterial compounds against S. Typhi and S. Paratyphi A.
- Published
- 2022
29. Essentiality Assessment of Cysteinyl and Lysyl-tRNA Synthetases of Mycobacterium smegmatis.
- Author
-
Sudha Ravishankar, Anisha Ambady, Rayapadi G Swetha, Anand Anbarasu, Sudha Ramaiah, and Vasan K Sambandamurthy
- Subjects
Medicine ,Science - Abstract
Discovery of mupirocin, an antibiotic that targets isoleucyl-tRNA synthetase, established aminoacyl-tRNA synthetase as an attractive target for the discovery of novel antibacterial agents. Despite a high degree of similarity between the bacterial and human aminoacyl-tRNA synthetases, the selectivity observed with mupirocin triggered the possibility of targeting other aminoacyl-tRNA synthetases as potential drug targets. These enzymes catalyse the condensation of a specific amino acid to its cognate tRNA in an energy-dependent reaction. Therefore, each organism is expected to encode at least twenty aminoacyl-tRNA synthetases, one for each amino acid. However, a bioinformatics search for genes encoding aminoacyl-tRNA synthetases from Mycobacterium smegmatis returned multiple genes for glutamyl (GluRS), cysteinyl (CysRS), prolyl (ProRS) and lysyl (LysRS) tRNA synthetases. The pathogenic mycobacteria, namely, Mycobacterium tuberculosis and Mycobacterium leprae, were also found to possess two genes each for CysRS and LysRS. A similar search indicated the presence of additional genes for LysRS in gram negative bacteria as well. Herein, we describe sequence and structural analysis of the additional aminoacyl-tRNA synthetase genes found in M. smegmatis. Characterization of conditional expression strains of Cysteinyl and Lysyl-tRNA synthetases generated in M. smegmatis revealed that the canonical aminoacyl-tRNA synthetase are essential, while the additional ones are not essential for the growth of M. smegmatis.
- Published
- 2016
- Full Text
- View/download PDF
30. Unravelling the Secrets of Mycobacterial Cidality through the Lens of Antisense.
- Author
-
Parvinder Kaur, Santanu Datta, Radha Krishan Shandil, Naveen Kumar, Nanduri Robert, Upneet K Sokhi, Supreeth Guptha, Shridhar Narayanan, Anand Anbarasu, and Sudha Ramaiah
- Subjects
Medicine ,Science - Abstract
One of the major impediments in anti-tubercular drug discovery is the lack of a robust grammar that governs the in-vitro to the in-vivo translation of efficacy. Mycobacterium tuberculosis (Mtb) is capable of growing both extracellular as well as intracellular; encountering various hostile conditions like acidic milieu, free radicals, starvation, oxygen deprivation, and immune effector mechanisms. Unique survival strategies of Mtb have prompted researchers to develop in-vitro equivalents to simulate in-vivo physiologies and exploited to find efficacious inhibitors against various phenotypes. Conventionally, the inhibitors are screened on Mtb under the conditions that are unrelated to the in-vivo disease environments. The present study was aimed to (1). Investigate cidality of Mtb targets using a non-chemical inhibitor antisense-RNA (AS-RNA) under in-vivo simulated in-vitro conditions.(2). Confirm the cidality of the targets under in-vivo in experimental tuberculosis. (3). Correlate in-vitro vs. in-vivo cidality data to identify the in-vitro condition that best predicts in-vivo cidality potential of the targets. Using cidality as a metric for efficacy, and AS-RNA as a target-specific inhibitor, we delineated the cidality potential of five target genes under six different physiological conditions (replicating, hypoxia, low pH, nutrient starvation, nitrogen depletion, and nitric oxide).In-vitro cidality confirmed in experimental tuberculosis in BALB/c mice using the AS-RNA allowed us to identify cidal targets in the rank order of rpoB>aroK>ppk>rpoC>ilvB. RpoB was used as the cidality control. In-vitro and in-vivo studies feature aroK (encoding shikimate kinase) as an in-vivo mycobactericidal target suitable for anti-TB drug discovery. In-vitro to in-vivo cidality correlations suggested the low pH (R = 0.9856) in-vitro model as best predictor of in-vivo cidality; however, similar correlation studies in pathologically relevant (Kramnik) mice are warranted. In the acute infection phase for the high fidelity translation, the compound efficacy may also be evaluated in the low pH, in addition to the standard replication condition.
- Published
- 2016
- Full Text
- View/download PDF
31. Role of SHV-11, a Class A β-Lactamase, Gene in Multidrug Resistance Among Klebsiella pneumoniae Strains and Understanding Its Mechanism by Gene Network Analysis
- Author
-
Sudha Ramaiah, Anand Anbarasu, and Sravan Kumar Miryala
- Subjects
Microbiology (medical) ,Pharmacology ,0303 health sciences ,biology ,030306 microbiology ,Klebsiella pneumoniae ,DNA damage ,DNA repair ,Immunology ,Drug resistance ,biochemical phenomena, metabolism, and nutrition ,biology.organism_classification ,Microbiology ,DnaA ,Multiple drug resistance ,03 medical and health sciences ,Antibiotic resistance ,bacteria ,Gene ,030304 developmental biology - Abstract
Aim: The rapid emergence of β-lactam resistance in gram-negative bacteria is a major problem in the treatment of infections caused by pathogenic bacterial strains, in particular Klebsiella pneumoniae. In our study, we are presenting a systems biology approach to understand the role of SHV-11 gene in drug resistance mechanism patterns in K. pneumoniae strain. Results: From the results, we have observed that the SHV-11 gene has a role in drug resistance mechanism along with its functional partner genes gyrA, parC, glsA, osmE, yjhA, yhdT, rimL, pepB, KPN_00437, and KPN_01875. We have also observed that of 51 genes, 27 genes were enriched in various Gene Ontology terms such as DNA metabolic process, DNA repair, and response to stress. The genes gyrA, parC, gyrB, parE, recA, dnaA, polB, dnaK, mutS, and dnaN constitute >41% of the total interactions; thus, these genes can be considered as hub nodes in the network, and they can be used as the potential drug targets. Conclusions: Drug exposure leads to the DNA damage in bacterial spp. We observed that the SHV11 gene along with the functional partners help in maintaining the genomic integrity by withstanding the environmental stress by inducing DNA damage repair mechanism. Our results provide a detailed understanding on the role of SHV-11 gene in drug resistance mechanisms in K. pneumoniae, and we are of the opinion that our results will be useful for researchers exploring the antibiotic resistance mechanisms in pathogenic bacteria.
- Published
- 2020
32. FN1 encoding fibronectin as a pivotal signaling gene for therapeutic intervention against pancreatic cancer
- Author
-
Gayathri Ashok, Sravan Kumar Miryala, Megha Treesa Saju, Anand Anbarasu, and Sudha Ramaiah
- Subjects
Pancreatic Neoplasms ,Gene Expression Regulation, Neoplastic ,Integrins ,Syndecans ,Gene Expression Profiling ,Genetics ,Biomarkers, Tumor ,Humans ,Gene Regulatory Networks ,General Medicine ,Adenocarcinoma ,Molecular Biology ,Fibronectins - Abstract
The delayed diagnosis of pancreatic cancer has resulted in rising mortality rate and low survival rate that can be circumvented using potent theranostics biomarkers. The treatment gets complicated with delayed detection resulting in lowered 5-year relative survival rate. In our present study, we employed systems biology approach to identify central genes that play crucial roles in tumor progression. Pancreatic cancer genes collected from various databases were used to construct a statistically significant interactome with 812 genes that was further analysed thoroughly using topological parameters and functional enrichment analysis. The significant genes in the network were then identified based on the maximum degree parameter. The overall survival analysis indicated through hazard ratio [HR] and gene expression [log Fold Change] across pancreatic adenocarcinoma revealed the critical role of FN1 [HR 1.4; log2(FC) 5.748], FGA [HR 0.78; log2(FC) 1.639] FGG [HR 0.9; log2(FC) 1.597], C3 [HR 1.1; log2(FC) 2.637], and QSOX1 [HR 1.4; log2(FC) 2.371]. The functional significance of the identified hub genes signified the enrichment of integrin cell surface interactions and proteoglycan syndecan-mediated cell signaling. The differential expression, low overall survival and functional significance of FN1 gene implied its possible role in controlling metastasis in pancreatic cancer. Furthermore, alternate splice variants of FN1 gene showed 10 protein coding transcripts with conserved cell attachment site and functional domains indicating the variants' potential role in pancreatic cancer. The strong association of the identified hub-genes can be better directed to design potential theranostics biomarkers for metastasized pancreatic tumor.
- Published
- 2021
33. Emergence of Meropenem Resistance Among Cefotaxime Non-susceptible
- Author
-
Rosemol, Varghese, Soumya, Basu, Ayyanraj, Neeravi, Agilakumari, Pragasam, V, Aravind, Richa, Gupta, Angel, Miraclin, Sudha, Ramaiah, Anand, Anbarasu, and Balaji, Veeraraghavan
- Abstract
The principal causative agent of acute bacterial meningitis (ABM) in children and the elderly is
- Published
- 2021
34. In-silico strategies to combat COVID-19: A comprehensive review
- Author
-
Sudha Ramaiah, Soumya Basu, and Anand Anbarasu
- Subjects
2019-20 coronavirus outbreak ,China ,COVID-19 Vaccines ,Coronavirus disease 2019 (COVID-19) ,Process (engineering) ,Computer science ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,In silico ,Bioengineering ,Molecular Dynamics Simulation ,Ligands ,Antiviral Agents ,Machine Learning ,Epitopes ,Artificial Intelligence ,Pandemic ,Global health ,Effective treatment ,Humans ,Computer Simulation ,Molecular Biology ,Pandemics ,COVID-19 ,Computational Biology ,Risk analysis (engineering) ,Drug Design ,Biotechnology - Abstract
The novel coronavirus SARS-CoV-2 since its emergence at Wuhan, China in December 2019 has been creating global health turmoil despite extensive containment measures and has resulted in the present pandemic COVID-19. Although the virus and its interaction with the host have been thoroughly characterized, effective treatment regimens beyond symptom-based care and repurposed therapeutics could not be identified. Various countries have successfully developed vaccines to curb the disease-transmission and prevent future outbreaks. Vaccination-drives are being conducted on a war-footing, but the process is time-consuming, especially in the densely populated regions of the world. Bioinformaticians and computational biologists have been playing an efficient role in this state of emergency to escalate clinical research and therapeutic development. However, there are not many reviews available in the literature concerning COVID-19 and its management. Hence, we have focused on designing a comprehensive review on in-silico approaches concerning COVID-19 to discuss the relevant bioinformatics and computational resources, tools, patterns of research, outcomes generated so far and their future implications to efficiently model data based on epidemiology; identify drug targets to design new drugs; predict epitopes for vaccine design and conceptualize diagnostic models. Artificial intelligence/machine learning can be employed to accelerate the research programs encompassing all the above urgent needs to counter COVID-19 and similar outbreaks.
- Published
- 2021
35. Aerobactin Seems To Be a Promising Marker Compared With Unstable RmpA2 for the Identification of Hypervirulent Carbapenem-Resistant Klebsiella pneumoniae: In Silico and In Vitro Evidence
- Author
-
Sathiya Shanmugam, Anand Anbarasu, Sudha Ramaiah, Soumya Basu, Purva Mathur, Binesh Lal, Balaji Veeraraghavan, Chaitra Shankar, and Karthick Vasudevan
- Subjects
Microbiology (medical) ,Genetics ,OXA-232 ,Klebsiella pneumoniae ,In silico ,Immunology ,carbapenem resistance ,Virulence ,Biology ,biology.organism_classification ,Phenotype ,Microbiology ,hypervirulent ,QR1-502 ,chemistry.chemical_compound ,Infectious Diseases ,Plasmid ,Antibiotic resistance ,chemistry ,aerobactin ,Aerobactin ,Replicon ,rmpA2 - Abstract
BackgroundThe incidence of hypervirulent (hv) carbapenem-resistant (CR)Klebsiella pneumoniae(Kp) is increasing globally among various clones and is also responsible for nosocomial infections. The CR-hvKp is formed by the uptake of a virulence plasmid by endemic high-risk clones or by the uptake of plasmids carrying antimicrobial resistance genes by the virulent clones. Here, we describe CR-hvKp from India belonging to high-risk clones that have acquired a virulence plasmid and are phenotypically unidentified due to lack of hypermucoviscosity.MethodsTwenty-seven CRKp isolates were identified to possessrmpA2by whole-genome sequencing; and resistance and virulence determinants were characterized. Byin silicoprotein modeling (and validation), protein backbone stability analysis, and coarse dynamics study, the fitness of RmpA, RmpA2, and aerobactin-associated proteins-IucA and IutA, were determined to establish a reliable marker for clinical identification of CR-hvKp.ResultsThe CR-hvKp belonged to multidrug-resistant (MDR) high-risk clones such as CG11, CG43, ST15, and ST231 and carried OXA-232 as the predominant carbapenemase followed by NDM. The virulence plasmid belonged to IncHI1B replicon type and carried frameshifted and truncatedrmpAandrmpA2. This resulted in a lack of hypermucoviscous phenotype. However, functional aerobactin was expressed in all high-risk clones.In silicoanalysis portrayed that IucA and IutA were more stable than classical RmpA. Furthermore, IucA and IutA had lower conformational fluctuations in the functional domains than the non-functional RmpA2, which increases the fitness cost of the latter for its maintenance and expression among CR-hvKp. Hence, RmpA and RmpA2 are likely to be lost among CR-hvKp owing to the increased fitness cost while coding for essential antimicrobial resistance and virulence factors.ConclusionIncreasing incidence of convergence of AMR and virulence is observed amongK. pneumoniaeglobally, which warrants the need for reliable markers for identifying CR-hvKp. The presence of non-functional RmpA2 among high-risk clones highlights the significance of molecular identification of CR-hvKp. The negative string test due to non-functional RmpA2 among CR-hvKp isolates challenges phenotypic screening and faster identification of this pathotype. This can potentially be counteracted by projecting aerobactin as a stable, constitutively expressed, and functional marker for rapidly evolving CR-hvKp.
- Published
- 2021
36. An IPTG Inducible Conditional Expression System for Mycobacteria.
- Author
-
Sudha Ravishankar, Anisha Ambady, Haripriya Ramu, Naina Vinay Mudugal, Ragadeepthi Tunduguru, Anand Anbarasu, Umender K Sharma, Vasan K Sambandamurthy, and Sudha Ramaiah
- Subjects
Medicine ,Science - Abstract
Conditional expression strains serve as a valuable tool to study the essentiality and to establish the vulnerability of a target under investigation in a drug discovery program. While essentiality implies an absolute requirement of a target function, vulnerability provides valuable information on the extent to which a target function needs to be depleted to achieve bacterial growth inhibition followed by cell death. The critical feature of an ideal conditional expression system is its ability to tightly regulate gene expression to achieve the full spectrum spanning from a high level of expression in order to support growth and near zero level of expression to mimic conditions of gene knockout. A number of bacterial conditional expression systems have been reported for use in mycobacteria. The utility of an isopropylthiogalactoside (IPTG) inducible system in mycobacteria has been reported for protein overexpression and anti-sense gene expression from a replicating multi-copy plasmid. Herein, we report the development of a versatile set of non-replicating IPTG inducible vectors for mycobacteria which can be used for generation of conditional expression strains through homologous recombination. The role of a single lac operator versus a double lac operator to regulate gene expression was evaluated by monitoring the expression levels of β-galactosidase in Mycobacterium smegmatis. These studies indicated a significant level of leaky expression from the vector with a single lac operator but none from the vector with double lac operator. The significance of the double lac operator vector for target validation was established by monitoring the growth kinetics of an inhA, a rpoB and a ftsZ conditional expression strain grown in the presence of different concentrations of IPTG. The utility of this inducible system in identifying target specific inhibitors was established by screening a focussed library of small molecules using an inhA and a rpoB conditional expression strain.
- Published
- 2015
- Full Text
- View/download PDF
37. A high-throughput cidality screen for Mycobacterium tuberculosis.
- Author
-
Parvinder Kaur, Anirban Ghosh, Ramya Vadageri Krishnamurthy, Deepa Gagwani Bhattacharjee, Vijayashree Achar, Santanu Datta, Shridhar Narayanan, Anand Anbarasu, and Sudha Ramaiah
- Subjects
Medicine ,Science - Abstract
Exposure to Mycobacterium tuberculosis (Mtb) aerosols is a major threat to tuberculosis (TB) researchers, even in bio-safety level-3 (BSL-3) facilities. Automation and high-throughput screens (HTS) in BSL3 facilities are essential for minimizing manual aerosol-generating interventions and facilitating TB research. In the present study, we report the development and validation of a high-throughput, 24-well 'spot-assay' for selecting bactericidal compounds against Mtb. The bactericidal screen concept was first validated in the fast-growing surrogate Mycobacterium smegmatis (Msm) and subsequently confirmed in Mtb using the following reference anti-tubercular drugs: rifampicin, isoniazid, ofloxacin and ethambutol (RIOE, acting on different targets). The potential use of the spot-assay to select bactericidal compounds from a large library was confirmed by screening on Mtb, with parallel plating by the conventional gold standard method (correlation, r2 = 0.808). An automated spot-assay further enabled an MBC90 determination on resistant and sensitive Mtb clinical isolates. The implementation of the spot-assay in kinetic screens to enumerate residual Mtb after either genetic silencing (anti-sense RNA, AS-RNA) or chemical inhibition corroborated its ability to detect cidality. This relatively simple, economical and quantitative HTS considerably minimized the bio-hazard risk and enabled the selection of novel vulnerable Mtb targets and mycobactericidal compounds. Thus, spot-assays have great potential to impact the TB drug discovery process.
- Published
- 2015
- Full Text
- View/download PDF
38. Non-steroidal anti-inflammatory drugs ketorolac and etodolac can augment the treatment against pneumococcal meningitis by targeting penicillin-binding proteins
- Author
-
Soumya Basu, Rosemol Varghese, Reetika Debroy, Sudha Ramaiah, Balaji Veeraraghavan, and Anand Anbarasu
- Subjects
Meningitis, Pneumococcal ,Anti-Inflammatory Agents, Non-Steroidal ,Anti-Inflammatory Agents ,Microbial Sensitivity Tests ,Microbiology ,Anti-Bacterial Agents ,Molecular Docking Simulation ,Infectious Diseases ,Bacterial Proteins ,Etodolac ,Humans ,Penicillin-Binding Proteins ,Child ,Ketorolac ,Aged - Abstract
Streptococcus pneumoniae is the principal etiological agent of acute bacterial meningitis (ABM) which has fatal outcome in children and elderly. Due to poor blood-brain barrier (BBB) permeation, conventional β-lactam antibiotics fail to establish the requisite bactericidal concentration in central nervous system leading to resistance in meningeal infections. The present study intended to identify potential therapeutic alternatives against Streptococcal meningitis.Virtual screening, pharmacokinetics/pharmacodynamics (PK/PD) and anti-bacterial evaluations were employed to screen potential drugs. Molecular docking and structural dynamics simulations were performed to analyze the binding affinity and interaction stability of the drugs against the conventional Penicillin binding protein (PBP) targets. Screened drugs were also checked for interactions with other possible Streptococcal targets and relevant host targets.Non-steroidal anti-inflammatory drugs (NSAIDs) ketorolac and etodolac exhibiting high BBB-permeation and anti-bacterial potency were identified. Ketorolac and etodolac possessed uniform binding affinities against PBP1A, PBP2X, PBP2B and PBP3 with low inhibition constants (50 μM). Against PBP2B and PBP3, higher binding affinities were observed for ketorolac (-6.45 and -6Kcal/mol respectively) and etodolac (-6.36 and -6.55Kcal/mol respectively) than penicillin (-5.95 and -5.85Kcal/mol respectively) and cefotaxime (-5.08 and -5.07Kcal/mol respectively). The binding affinities were contributed by conventional H-bonds and non-canonical interactions with active site residues of PBPs. Structural dynamics simulations further indicated the overall stability of the drug-bound complexes through minimal overall average root-mean square fluctuations (RMSFs) (1.0 Å). The average binding affinities of Ketorolac and Etodolac with PBPs were marginally higher than other Streptococcal targets and comparable to their conventional inflammatory targets.Pharmacological and structural profiles indicated that ketorolac and etodolac can potentially subdue the cause and effects of streptococcal meningitis and hence encourage experimental validations.
- Published
- 2022
39. Identification of Potential Carboxylic Acid-Containing Drug Candidate to Design Novel Competitive NDM Inhibitors: An In-Silico Approach Comprising Combined Virtual Screening and Molecular Dynamics Simulation
- Author
-
Soumya Basu, Aniket Naha, Amala Arumugam, Sudha Ramaiah, Anand Anbarasu, Karthick Vasudevan, and Balaji Veeraraghavan
- Subjects
chemistry.chemical_classification ,Virtual screening ,biology ,Chemistry ,medicine.drug_class ,Carboxylic acid ,In silico ,Antibiotics ,Active site ,biology.organism_classification ,Combinatorial chemistry ,chemistry.chemical_compound ,biology.protein ,medicine ,Target protein ,Lead compound ,Bacteria - Abstract
Metallo-β-lactamases (MBLs) producing bacteria especially the ones with New Delhi metallo-beta-lactamase-1 (NDM-1) and its variants can potentially hydrolyse all the major β-lactam antibiotics, ultimately escalating anti-microbial resistance world-wide. There is a dearth of approved inhibitors to combat NDM and other MBLs producing bacteria. Hence we focussed to find novel inhibitor(s) in-silico which can potentially suppress the activity of NDM/MBLs. A total of 2400 compounds were virtually screened to identify a promising carboxylic acid-containing compound (CID-53986787) analogous to NDM antagonist Captopril. Our lead compound can bind adjacent to the active site zinc ions (Zn1 and Zn2) in all highly resistant NDM variants. CID-53986787 possesses ~ 5–8% higher binding affinity than Captopril, exhibiting molecular interactions with crucial residues that can destabilize the hydrolytic activity of NDM. CID-53986787 was virtually evaluated to ascertain its safe pharmacological/toxicity profile. Molecular dynamics simulation studies further elucidated its stable interaction with the target protein (NDM-1).
- Published
- 2021
40. Molecular docking and dynamics studies on novel benzene sulfonamide substituted pyrazole-pyrazoline analogues as potent inhibitors of Plasmodium falciparum Histo aspartic protease
- Author
-
Mahalakshmi Thillainayagam, Sudha Ramaiah, and Anand Anbarasu
- Subjects
0303 health sciences ,biology ,Stereochemistry ,030303 biophysics ,Sulfonamide (medicine) ,Pyrazoline ,Plasmodium falciparum ,General Medicine ,Pyrazole ,medicine.disease ,biology.organism_classification ,03 medical and health sciences ,chemistry.chemical_compound ,chemistry ,Aspartate protease ,Structural Biology ,parasitic diseases ,medicine ,Molecular Biology ,Malaria ,medicine.drug - Abstract
Malaria is the major health issue in African, Asian and Mediterranean regions of the world. Due to the emerging resistance by the parasites and mosquitoes for the current medications and insecticid...
- Published
- 2019
41. Impact of bedaquiline and capreomycin on the gene expression patterns of multidrug‐resistant Mycobacterium tuberculosis H37Rv strain and understanding the molecular mechanism of antibiotic resistance
- Author
-
Sudha Ramaiah, Anand Anbarasu, and Sravan Kumar Miryala
- Subjects
0301 basic medicine ,Capreomycin ,Virulence Factors ,Antitubercular Agents ,Biology ,Biochemistry ,Microbiology ,Mycobacterium tuberculosis ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Antibiotic resistance ,Bacterial Proteins ,Gene interaction ,Drug Resistance, Multiple, Bacterial ,medicine ,Gene Regulatory Networks ,Multidrug-Resistant Mycobacterium tuberculosis ,Diarylquinolines ,Molecular Biology ,Oligonucleotide Array Sequence Analysis ,Gene Expression Profiling ,Cell Biology ,biology.organism_classification ,Multiple drug resistance ,030104 developmental biology ,Regulon ,chemistry ,030220 oncology & carcinogenesis ,Bedaquiline ,medicine.drug - Abstract
The emergence of multidrug resistance (MDR), extensively drug-resistant, and total drug-resistant Mycobacterium tuberculosis (Mtb) strains have hampered the treatment of tuberculosis (TB). Capreomycin and Bedaquiline are currently used for MDR-TB treatment. To understand the impact of these antibiotics on Mtb genes, we have curated the gene expression data where the Mtb cultures were exposed to the Bedaquiline and Capreomycin. Based on the P value cut off (0.05) and logFC (-0.5 and+0.5) values, we have selected the top differentially expressed genes during the antibiotic exposures. We have observed that the top differentially expressed Mtb genes were related to universal stress genes, two-component regulatory systems, and drug efflux pumps. We have curated the Mtb gene datasets and carried out the functional over-representation analysis using the individual gene expression values. We further, constructed the gene interaction networks of antibiotic resistance genes and virulence genes of Mtb to understand the impact of the antibiotics at the molecular level and thus to understand the antimicrobial resistance and virulence patterns. Our study elucidates the impact of antibiotics on the Mtb genes at the molecular level and the positively enriched pathways, operons, and regulons data are helpful in understanding the resistance patterns in Mtb. The upregulated genes during the exposure of Bedaquiline and Capreomycin can be considered as potent drug targets for the development of new anti-TB drugs.
- Published
- 2019
42. Full title: Identification of potential drug targets against carbapenem resistant Enterobacteriaceae (CRE) strains using in silico gene network analysis
- Author
-
Manabendra Dutta Choudhury, Amitabha Bhattacharjee, Sheuli Kangsa Banik, Anand Anbarasu, Somorita Baishya, and Anupam Das Talukdar
- Subjects
0301 basic medicine ,biology ,medicine.drug_class ,In silico ,Antibiotics ,Gene regulatory network ,Carbapenem-resistant enterobacteriaceae ,Computational biology ,biology.organism_classification ,Enterobacteriaceae ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,Antibiotic resistance ,030220 oncology & carcinogenesis ,Genetics ,medicine ,Gene silencing ,Gene - Abstract
In the era where issue of antibiotic resistance is increasing at an alarming rate and resistance to most antibiotics has occurred, carbapenems have been the choice of drug against most infection because of its unique structure. However due to lack of antibiotic policy carbapenems too have achieved resistance and led to the emergence of carbapenem resistant Enterobacteriaceae (CRE). Members of Enterobacteriaceae family produce New Delhi metallo-beta-lactamase (NDM), a type of carbapenemase that can cleave carbapenems. Therefore, new anti-microbial targets need to be identified and for this purpose a holistic model is designed in this approach in order to find out the influential genes that are liable in imparting carbapenem resistance owing to the presence of NDM. In this research approach, firstly genes associated with resistance owing to NDM are collected from NCBI database. A total of 419 genes from E. coli that have been obtained from NCBI were subjected to STRING for protein-protein interaction analysis. Out of 419 genes, only 59 genes showed interaction. STRING gave 1679 functional partners at different confidence levels. In the next stage, clustering analysis of the 1679 functional partners was done using MCODE app of Cytoscape software which generated 71 clusters. Topological properties of the 804 functional partners obtained from the 71 clusters were done using Network Analyser plugin of Cytoscape software. 797 functional partners were streamlined and they were subjected to functional enrichment analysis by DAVID Database. This database finally gave 21 genes from 15 clusters, thus indicating that these 15 genes might have a crucial role in the development of carbapenem resistance owing to NDM. These genes can be targeted for designing new anti-microbial drugs in future by the way of gene silencing or altering the genetic expression.
- Published
- 2019
43. Identification of potential inhibitors for Klebsiella pneumoniae carbapenemase-3: a molecular docking and dynamics study
- Author
-
Kullappan Malathi, Sudha Ramaiah, and Anand Anbarasu
- Subjects
0303 health sciences ,Imipenem ,biology ,Klebsiella pneumoniae ,medicine.drug_class ,Chemistry ,030303 biophysics ,Cephalosporin ,Antibiotics ,General Medicine ,Drug resistance ,Sulbactam ,biochemical phenomena, metabolism, and nutrition ,bacterial infections and mycoses ,biology.organism_classification ,Microbiology ,Penicillin ,03 medical and health sciences ,Structural Biology ,Clavulanic acid ,polycyclic compounds ,medicine ,Molecular Biology ,medicine.drug - Abstract
Klebsiella pneumoniae (K. pneumoniae) is a Gram-negative bacterium, which is a leading causal agent for nosocomial infections. Penicillin, cephalosporin and carbapenems along with the inhibitors such as tazobactam, sulbactam and clavulanic acid are prescribed for the treatment of K. pneumoniae infections. Prolonged exposure to β-lactam antibiotics leads to the development of resistance. The major reason for the β-lactam resistance in K. pneumoniae is the secretion of the enzyme K. pneumoniae carbapenemase (KPC). Secretion of KPC-2 and its variant KPC-3 by the K. pneumoniae strains causes resistance to both the substrate imipenem and the β-lactamase inhibitors. Hence, molecular docking and dynamics studies were carried out to analyze the resistance mechanism of KPC-2-imipenem and KPC-3-imipenem at the structural level. It reveals that KPC-3-imipenem has the highest c-score value of 4.03 with greater stability than the KPC-2-imipenem c-score value of 2.36. Greater the interaction between the substrate and the β-lactamase enzyme, higher the chances of hydrolysis of the substrate. Presently available β-lactamase inhibitors are also ineffective against KPC-3-expressing strains. This situation necessitates the need for development of novel and effective inhibitors for KPC-3. We have carried out the virtual screening process to identify more effective inhibitors for KPC-3, and this has resulted in ZINC48682523, ZINC50209041 and ZINC50420049 as the best binding energy compounds, having greater binding affinity and stability than KPC-3-tazobactam interactions. Our study provides a clear understanding of the mechanism of drug resistance and provides valuable inputs for the development of inhibitors against KPC-3 expressing K. pneumoniae. Communicated by Ramaswamy H. Sarma.
- Published
- 2019
44. Detection of OXA-1 β-lactamase gene of Klebsiella pneumoniae from blood stream infections (BSI) by conventional PCR and in-silico analysis to understand the mechanism of OXA mediated resistance.
- Author
-
Madhan Sugumar, K M Kumar, Anand Manoharan, Anand Anbarasu, and Sudha Ramaiah
- Subjects
Medicine ,Science - Abstract
Klebsiella pneumoniae strains producing extended-spectrum β-lactamases (ESBL) exhibit resistance to antibiotic classes. The production of ESBLs (TEM-1, TEM-2, SHV-1, OXA-1) results in resistance to ampicillin, ticarcillin, piperacillin and cephalosporins. High levels of β-lactamases leads to development of resistance to β-lactamase inhibitors. The present study deals with characterizing antimicrobial resistance pattern among septicemia causing K. pneumoniae and the prevalence of inhibitor resistant OXA-1 β-lactamase genes among them. Of 151 study isolates, 59 were resistant to piperacillin/tazobactam and these isolates were further selected for blaOXA-1 screening. Amplification of β-lactamases genes by conventional PCR showed the presence of blaOXA-1 genes among 12 K. pneumoniae (20.3%) isolates. OXA-1 β-lactamase producing strains were found to be resistant to piperacillin/tazobactam(100%), levofloxacin (91.6%), amikacin (75%), cefoxitin (50%), ertapenem (25%), imipenem (16.6%) and meropenem (16.6%); all were susceptible to tigecycline. 3D models of OXA-1 β-lactamase were generated and docking was performed with various β-lactam antibiotics. Molecular docking (MD) revealed the molecular basis of drug sensitivity. MD simulation results clearly confirmed the notable loss in stability for tigecycline-blaOXA-1 complex. Findings of the present study will provide useful insights for understanding the mechanism of resistance and help with strategies for the development of new antibiotics. The conventional PCR assay designed in this study can be routinely used in clinical microbiology laboratories to determine the blaOXA-1 genes.
- Published
- 2014
- Full Text
- View/download PDF
45. In silico structure evaluation of BAG3 and elucidating its association with bacterial infections through protein-protein and host-pathogen interaction analysis
- Author
-
Anand Anbarasu, Sudha Ramaiah, Soumya Basu, Aniket Naha, and Balaji Veeraraghavan
- Subjects
0301 basic medicine ,RHOA ,Viral pathogenesis ,Host–pathogen interaction ,In silico ,Apoptosis ,Computational biology ,Molecular Dynamics Simulation ,BAG3 ,Gram-Positive Bacteria ,Biochemistry ,Interactome ,Protein Structure, Secondary ,Protein–protein interaction ,Machine Learning ,03 medical and health sciences ,0302 clinical medicine ,Protein Domains ,Gram-Negative Bacteria ,Humans ,Protein Interaction Maps ,Molecular Biology ,Adaptor Proteins, Signal Transducing ,Cell Proliferation ,biology ,Cell Biology ,Bacterial Infections ,TLR2 ,030104 developmental biology ,Gene Ontology ,030220 oncology & carcinogenesis ,Host-Pathogen Interactions ,biology.protein ,Apoptosis Regulatory Proteins ,Protein Binding - Abstract
BAG3, a co-chaperone protein with a Bcl-2-associated athanogene (BAG) domain, has diverse functionalities in protein-folding, apoptosis, inflammation, and cell cycle regulatory cross-talks. It has been well characterised in cardiac diseases, cancers, and viral pathogenesis. The multiple roles of BAG3 are attributed to its functional regions like BAG, Tryptophan-rich (WW), isoleucine-proline-valine-rich (IPV), and proline-rich (PXXP) domains. However, to study its structural impact on various functions, the experimental 3D structure of BAG3 protein was not available. Hence, the structure was predicted through in silico modelling and validated through computational tools and molecular dynamics simulation studies. To the best of our knowledge, the role of BAG3 in bacterial infections is not explicitly reported. We attempted to study them through an in-silico protein-protein interaction network and host-pathogen interaction analysis. From structure-function relationships, it was identified that the WW and PXXP domains were associated with cellular cytoskeleton rearrangement and adhesion-mediated response, which might be involved in BAG3-related intracellular bacterial proliferation. From functional enrichment analysis, Gene Ontology terms and topological matrices, 18 host proteins and 29 pathogen proteins were identified in the BAG3 interactome pertaining to Legionellosis, Tuberculosis, Salmonellosis, Shigellosis, and Pertussis through differential phosphorylation events associated with serine metabolism. Furthermore, it was evident that direct (MAPK8, MAPK14) and associated (MAPK1, HSPD1, NFKBIA, TLR2, RHOA) interactors of BAG3 could be considered as therapeutic markers to curb down intracellular bacterial propagation in humans.
- Published
- 2021
46. Transcriptional expression of secondary resistance genes ccdB and repA2 is enhanced in presence of cephalosporin and carbapenem in Escherichia coli
- Author
-
Anupam Das Talukdar, Somorita Baishya, Anand Anbarasu, Bhaskar Das, Jayalaxmi Wangkheimayum, Amitabha Bhattacharjee, Manabendra Dutta Choudhury, and Chandrayee Deshamukhya
- Subjects
Microbiology (medical) ,Carbapenem ,Imipenem ,medicine.drug_class ,Secondary resistance ,Cephalosporin ,lcsh:QR1-502 ,ccdB ,Context (language use) ,Microbial Sensitivity Tests ,Biology ,Microbiology ,lcsh:Microbiology ,Plasmid maintenance ,03 medical and health sciences ,Plasmid ,Bacterial Proteins ,polycyclic compounds ,Escherichia coli ,medicine ,Gene ,Carabapenem ,030304 developmental biology ,repA2 ,0303 health sciences ,030306 microbiology ,Escherichia coli Proteins ,Gene Expression Regulation, Bacterial ,biochemical phenomena, metabolism, and nutrition ,bacterial infections and mycoses ,Anti-Bacterial Agents ,Cephalosporins ,Resistome ,Carbapenems ,Research Article ,medicine.drug - Abstract
Background The issue of carbapenem resistance in E.coli is very concerning and it is speculated that cumulative effect of both primary resistance genes and secondary resistance genes that act as helper to the primary resistance genes are the reason behind their aggravation. Therefore, here we attempted to find the role of two secondary resistance genes (SRG) ccdB and repA2 in carbapenem resistance in E. coli (CRE). In this context influential genes belonging to secondary resistome that act as helper to the primary resistance genes like blaNDM and blaCTX-M in aggravating β-lactam resistance were selected from an earlier reported in silico study. Transcriptional expression of the selected genes in clinical isolates of E.coli that were discretely harboring blaNDM-1, blaNDM-4, blaNDM-5, blaNDM-7 and blaCTX-M-15 with and without carbapenem and cephalosporin stress (2 μg/ml) was determined by real time PCR. Cured mutants sets that were lacking (i) primary resistance genes, (ii) secondary resistance genes and (iii) both primary and secondary resistance genes were prepared by SDS treatment. These sets were then subjected to antibiotic susceptibility testing by Kirby Bauer disc diffusion method. Results Out of the 21 genes reported in the in silico study, 2 genes viz.repA2 and ccdB were selected for transcriptional expression analysis. repA2, coding replication regulatory protein, was downregulated in response to carbapenems and cephalosporins. ccdB, coding for plasmid maintenance protein, was also downregulated in response to carbapenems except imipenem and cephalosporins. Following plasmid elimination assay increase in diameter of zone of inhibition under stress of both antibiotics was observed as compared to uncured control hinting at the reversion of antibiotic susceptibility by the-then resistant bacteria. Conclusion SRGs repA2 and ccdB help sustenance of blaNDM and blaCTX-M under carbapenem and cephalosporin stress.
- Published
- 2021
47. Computational Study of ADD1 Gene Polymorphism Associated with Hypertension
- Author
-
Kundu, Arpita and Anand, Anbarasu
- Published
- 2013
- Full Text
- View/download PDF
48. Gene interaction network to unravel the role of gut bacterial species in cardiovascular diseases: E. coli O157:H7 host-bacterial interaction study
- Author
-
Sravan Kumar Miryala, Sudha Ramaiah, and Anand Anbarasu
- Subjects
0301 basic medicine ,RHOA ,Gene regulatory network ,Health Informatics ,Biology ,Escherichia coli O157 ,Protein–protein interaction ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Humans ,EP300 ,Gene ,Genetics ,Bacteria ,Host Microbial Interactions ,Drug discovery ,medicine.disease ,Computer Science Applications ,Gastrointestinal Microbiome ,030104 developmental biology ,Cardiovascular Diseases ,biology.protein ,Human genome ,Dysbiosis ,030217 neurology & neurosurgery - Abstract
Background Cardiovascular Disease (CVD) is one of the most common causes of mortality in humans. Presently, the role of pathogens in the initiation and progression of the CVDs is not clearly understood. Hence, it is essential to understand the molecular-level interactions between the human proteins and the microbial proteins to deduce their functional roles in the CVDs. Method The host-pathogen interactions (HPI) related to CVDs in the case of E. coli str. O157:H7 colonization were curated, and also the protein-protein interactions (PPI) between humans and E. coli were collected. Gene interaction network (GIN) and functional enrichment analyses (FEA) were utilized for this. Results The GIN revealed dense interactions between the functional partners. The FEA indicated that the essential pathways played a significant role in humans as well as in E. coli. The primary responses against most of the bacterial pathogens in humans are different from that of E. coli; Terpenoid biosynthesis and production of secondary metabolite pathways aid the survival of the E. coli inside the host. Interestingly, network analysis divulged that the E. coli genes ksgA, rpsT, ispE, rpsI, ispH, and the human genes TP53, CASP3, CYCS, EP300, RHOA communicated by significant numbers in direct interactions. Conclusions The results obtained from the present study will help researchers understand the molecular-level interactions in the CVDs between the human and the E. coli genes. The important genes with vital interactions can be considered as hub molecules and can be exploited for new drug discovery.
- Published
- 2020
49. Novel cyclohexanone compound as a potential ligand against SARS-CoV-2 main-protease
- Author
-
Balaji Veeraraghavan, Soumya Basu, Anand Anbarasu, and Sudha Ramaiah
- Subjects
0301 basic medicine ,Drug ,Viral Protease Inhibitors ,medicine.medical_treatment ,media_common.quotation_subject ,030106 microbiology ,Cyclohexanone ,Molecular Dynamics Simulation ,Ligands ,Antiviral Agents ,Microbiology ,Article ,Docking ,03 medical and health sciences ,chemistry.chemical_compound ,Catalytic Domain ,medicine ,Pharmacokinetics ,Coronavirus 3C Proteases ,media_common ,Protease ,Nucleoside analogue ,biology ,Cyclohexanones ,SARS-CoV-2 ,Anti-viral activity ,Active site ,COVID-19 ,Lopinavir ,Combinatorial chemistry ,COVID-19 Drug Treatment ,Molecular Docking Simulation ,030104 developmental biology ,Infectious Diseases ,chemistry ,SARS-CoV-2 mpro ,Docking (molecular) ,Curcumin ,biology.protein ,medicine.drug - Abstract
No commercially available drug candidate has yet been devised which is unique to and not repurposed against SARS-CoV-2 and has high efficacy or safe toxicity profile or both. Taking curcumin as a reference compound, we identified a new commercially available cyclohexanone compound, ZINC07333416 with binding energy (−8.72 kcal/mol) better than that of popularly devised anti-Covid-19 drugs like viral protease inhibitor Lopinavir, nucleoside analogue Remdesivir and the repurposed drug hydroxychloroquine when targeted to the active-site of SARS-CoV-2 Main protease (Mpro) through docking studies. The ligand ZINC07333416 exhibits crucial interactions with major active site residues of SARS-CoV-2 Mpro viz. Cys145 and His41 involving in the protease activity; as well as GLU-166 and ASN-142 which plays the pivotal role in the protein-dimerization. The protein-ligand stable interaction was further confirmed with molecular dynamics simulation (MDS) studies. Based on virtual assessment, ZINC07333416 also have significant values in terms of medicinal chemistry, pharmacokinetics, synthetic accessibility and anti-viral activity that encourage its experimental applications against COVID-19., Highlights •We screened commercially available compounds with curcumin as a reference to specifically pertain to the anti-viral potential and safe toxicity profile of the later. •We checked the binding properties of lead compound and previously reported compounds against SARS-CoV-2 Mpro, besides comparing their pharmacological and toxicity profile. A novel cyclohexanone compound was identified with favourable drug attributes and eliciting stable molecular interactions with SARS-CoV-2 Mpro.
- Published
- 2020
- Full Text
- View/download PDF
50. Gene interaction network approach to elucidate the multidrug resistance mechanisms in the pathogenic bacterial strain Proteus mirabilis
- Author
-
Sudha Ramaiah, Anand Anbarasu, and Sravan Kumar Miryala
- Subjects
0301 basic medicine ,Physiology ,Clinical Biochemistry ,Gene regulatory network ,03 medical and health sciences ,0302 clinical medicine ,Antibiotic resistance ,Drug Resistance, Multiple, Bacterial ,Humans ,Gene Regulatory Networks ,Gene ,Pathogen ,Proteus mirabilis ,Phylogeny ,Genetics ,biology ,Cell Biology ,biology.organism_classification ,rpoB ,Anti-Bacterial Agents ,Multiple drug resistance ,030104 developmental biology ,030220 oncology & carcinogenesis ,Urinary Tract Infections ,Bacteria - Abstract
Proteus mirabilis is one among the most frequently identified pathogen in patients with the urinary tract infection. The multidrug resistance exhibited by P. mirabilis renders the treatment ineffective, and new progressive strategies are needed to overcome the antibiotic resistance (AR). We have analyzed the evolutionary relationship of 29 P. mirabilis strains available in the National Center for Biotechnology Information-Genome database. The antimicrobial resistance genes of P. mirabilis along with the enriched pathways and the Gene Ontology terms are analyzed using gene networks to understand the molecular basis of AR. The genes rpoB, tufB, rpsl, fusA, and rpoA could be exploited as potential drug targets as they are involved in regulating the vital functions within the bacterium. The drug targets reported in the present study will aid researchers in developing new strategies to combat multidrug-resistant P. mirabilis.
- Published
- 2020
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.