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Pathan SU, Kharwar A, Ibrahim MA, Singh SB, Bajaj P. Enzymes as indispensable markers in disease diagnosis. Bioanalysis 2024. [PMID: 38530222 DOI: 10.4155/bio-2023-0207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/27/2024] Open
Abstract
Enzymes have been used for disease diagnosis for many decades; however, advancements in technology like ELISA and flow cytometry-based detection have significantly increased their use and have increased the sensitivity of detection. Technological advancements in recombinant enzyme production have increased enzymatic stability, and the use of colorimetric-based and florescence-based assays has led to their increased use as biomarkers for disease detection. Enzymes like acid phosphatase, cathepsin, lactate dehydrogenase, thymidine kinase and creatine kinase are indispensable markers for diagnosing cancer, cardiovascular diseases and others. This minireview summarizes various enzymes used in disease diagnosis, their metabolic role, market value and potential as disease markers across various metabolic and other disorders.
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Affiliation(s)
- Shehabaz Usman Pathan
- National Institute of Pharmaceutical Education & Research, Balanagar, Hyderabad, 500037, India
| | - Akash Kharwar
- National Institute of Pharmaceutical Education & Research, Balanagar, Hyderabad, 500037, India
| | - Madaje Amir Ibrahim
- National Institute of Pharmaceutical Education & Research, Balanagar, Hyderabad, 500037, India
| | - Shashi Bala Singh
- National Institute of Pharmaceutical Education & Research, Balanagar, Hyderabad, 500037, India
| | - Priyanka Bajaj
- National Institute of Pharmaceutical Education & Research, Balanagar, Hyderabad, 500037, India
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2
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Bajaj P, Bhasin M, Varadarajan R. Molecular bases for strong phenotypic effects of single synonymous codon substitutions in the E. coli ccdB toxin gene. BMC Genomics 2023; 24:732. [PMID: 38049728 PMCID: PMC10694988 DOI: 10.1186/s12864-023-09817-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Accepted: 11/18/2023] [Indexed: 12/06/2023] Open
Abstract
BACKGROUND Single synonymous codon mutations typically have only minor or no effects on gene function. Here, we estimate the effects on cell growth of ~ 200 single synonymous codon mutations in an operonic context by mutating almost all positions of ccdB, the 101-residue long cytotoxin of the ccdAB Toxin-Antitoxin (TA) operon to most degenerate codons. Phenotypes were assayed by transforming the mutant library into CcdB sensitive and resistant E. coli strains, isolating plasmid pools, and subjecting them to deep sequencing. Since autoregulation is a hallmark of TA operons, phenotypes obtained for ccdB synonymous mutants after transformation in a RelE toxin reporter strain followed by deep sequencing provided information on the amount of CcdAB complex formed. RESULTS Synonymous mutations in the N-terminal region involved in translation initiation showed the strongest non-neutral phenotypic effects. We observe an interplay of numerous factors, namely, location of the codon, codon usage, t-RNA abundance, formation of anti-Shine Dalgarno sequences, predicted transcript secondary structure, and evolutionary conservation in determining phenotypic effects of ccdB synonymous mutations. Incorporation of an N-terminal, hyperactive synonymous mutation, in the background of the single synonymous codon mutant library sufficiently increased translation initiation, such that mutational effects on either folding or termination of translation became more apparent. Introduction of putative pause sites not only affects the translational rate, but might also alter the folding kinetics of the protein in vivo. CONCLUSION In summary, the study provides novel insights into diverse mechanisms by which synonymous mutations modulate gene function. This information is useful in optimizing heterologous gene expression in E. coli and understanding the molecular bases for alteration in gene expression that arise due to synonymous mutations.
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Affiliation(s)
- Priyanka Bajaj
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India
- Present address: Department of Bioengineering and Therapeutic Sciences, University of CA - San Francisco, San Francisco, CA, 94158, USA
| | - Munmun Bhasin
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India
| | - Raghavan Varadarajan
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India.
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3
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Bhardwaj M, Kamble P, Mundhe P, Jindal M, Thakur P, Bajaj P. Multifaceted personality and roles of heme enzymes in industrial biotechnology. 3 Biotech 2023; 13:389. [PMID: 37942054 PMCID: PMC10630290 DOI: 10.1007/s13205-023-03804-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 07/29/2023] [Indexed: 11/10/2023] Open
Abstract
Heme enzymes are the most prominent category of iron-containing metalloenzymes with the capability of catalyzing an astonishingly wide range of reactions like epoxidation, hydroxylation, demethylation, desaturation, reduction, sulfoxidation, and decarboxylation. Various enzymes in this category are P450s, heme peroxidases, catalases, myoglobin, cytochrome C, and others. Besides this, the natural promiscuity and amenability of these enzymes to protein engineering and evolution have also added several non-native reactions such as C-H, N-H, S-H insertions, cyclopropanation, and other industrially important reactions to their capabilities. Surprisingly, all of these reactions and their wide substrate scopes are attributed to changes in the active site scaffold of different heme enzymes as the center of all enzymes is constituted by a porphyrin ring containing iron. Multiple prominent research groups across the world, including 2018, Nobel Laureate Frances Arnold's group, have shown keen interest in engineering and evolving these enzymes for utilizing their industrial potential. Besides engineering the active site, researchers have also explored the possibility of these enzymes catalyzing non-native reactions by replacing the center porphyrin ring with other cofactors or by changing the iron in the porphyrin ring with other metal ions along with engineering the active site and thereby creating novel artificial metalloenzymes. Thus, in this mini-review from our group, for the first time, we are trying to catalog various activities catalyzed by heme enzymes and their engineered variants and their active usage in various industries along with shedding light on their potential for use in various applications in the future.
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Affiliation(s)
- Mahipal Bhardwaj
- Department of Chemical Sciences, National Institute of Pharmaceutical Education and Research (NIPER), Kukatpally Industrial Estate, NH-9, Balanagar, Hyderabad, Telangana 500037 India
| | - Pranay Kamble
- Department of Chemical Sciences, National Institute of Pharmaceutical Education and Research (NIPER), Kukatpally Industrial Estate, NH-9, Balanagar, Hyderabad, Telangana 500037 India
| | - Priyanka Mundhe
- Department of Chemical Sciences, National Institute of Pharmaceutical Education and Research (NIPER), Kukatpally Industrial Estate, NH-9, Balanagar, Hyderabad, Telangana 500037 India
| | - Monika Jindal
- Department of Chemical Sciences, National Institute of Pharmaceutical Education and Research (NIPER), Kukatpally Industrial Estate, NH-9, Balanagar, Hyderabad, Telangana 500037 India
| | - Payal Thakur
- CSIR-Institute of Microbial Technology (IMTech), Sector-39A, Chandigarh, 160036 India
| | - Priyanka Bajaj
- Department of Chemical Sciences, National Institute of Pharmaceutical Education and Research (NIPER), Kukatpally Industrial Estate, NH-9, Balanagar, Hyderabad, Telangana 500037 India
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Bajaj P, Ivlev A, Räth C, Schwabe M. Studying turbulence in a fluid with background damping. Phys Rev E 2023; 107:064603. [PMID: 37464622 DOI: 10.1103/physreve.107.064603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 04/26/2023] [Indexed: 07/20/2023]
Abstract
In this experimental paper, we demonstrate that turbulence can develop in a fluid system with background damping. For that purpose, we analyze dust acoustic waves, self-excited in a fluid complex plasma where the motion of individual microparticles was recorded with a high-speed video camera. We use the Wiener-Khinchin theorem to calculate the kinetic spectrum during different phases of the highly nonlinear periodic wave motion and show that a turbulent cascade develops at the phases of highest particle compression. We demonstrate that the energy cascade occurs despite the presence of a damping force due to the background neutral gas.
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Affiliation(s)
- P Bajaj
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51147 Köln, Germany
| | - A Ivlev
- Max-Planck-Institut für Extraterrestrische Physik, 85741 Garching, Germany
| | - C Räth
- Institut für KI Sicherheit, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 89081 Ulm, Germany
| | - M Schwabe
- Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Physik der Atmosphäre, 82234 Oberpfaffenhofen, Germany
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Majem M, Forster M, Krebs M, Peguero J, Clay T, Felip E, Iams W, Roxburgh P, de Spéville BD, Bajaj P, Mueller C, Triebel F. 11MO Final data from a phase II study (TACTI-002) of eftilagimod alpha (soluble LAG-3) and pembrolizumab in 2nd-line metastatic NSCLC pts resistant to PD-1/PD-L1 inhibitors. J Thorac Oncol 2023. [DOI: 10.1016/s1556-0864(23)00265-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
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6
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Rajakumara E, Saniya D, Bajaj P, Rajeshwari R, Giri J, Davari MD. Hijacking Chemical Reactions of P450 Enzymes for Altered Chemical Reactions and Asymmetric Synthesis. Int J Mol Sci 2022; 24:ijms24010214. [PMID: 36613657 PMCID: PMC9820634 DOI: 10.3390/ijms24010214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/09/2022] [Accepted: 12/12/2022] [Indexed: 12/25/2022] Open
Abstract
Cytochrome P450s are heme-containing enzymes capable of the oxidative transformation of a wide range of organic substrates. A protein scaffold that coordinates the heme iron, and the catalytic pocket residues, together, determine the reaction selectivity and regio- and stereo-selectivity of the P450 enzymes. Different substrates also affect the properties of P450s by binding to its catalytic pocket. Modulating the redox potential of the heme by substituting iron-coordinating residues changes the chemical reaction, the type of cofactor requirement, and the stereoselectivity of P450s. Around hundreds of P450s are experimentally characterized, therefore, a mechanistic understanding of the factors affecting their catalysis is increasingly vital in the age of synthetic biology and biotechnology. Engineering P450s can enable them to catalyze a variety of chemical reactions viz. oxygenation, peroxygenation, cyclopropanation, epoxidation, nitration, etc., to synthesize high-value chiral organic molecules with exceptionally high stereo- and regioselectivity and catalytic efficiency. This review will focus on recent studies of the mechanistic understandings of the modulation of heme redox potential in the engineered P450 variants, and the effect of small decoy molecules, dual function small molecules, and substrate mimetics on the type of chemical reaction and the catalytic cycle of the P450 enzymes.
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Affiliation(s)
- Eerappa Rajakumara
- Macromolecular Structural Biology Lab, Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy 502284, India
- Correspondence: (E.R.); (M.D.D.)
| | - Dubey Saniya
- Macromolecular Structural Biology Lab, Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy 502284, India
| | - Priyanka Bajaj
- Department of Chemical Sciences, National Institute of Pharmaceutical Education and Research (NIPER), NH-44, Balanagar, Hyderabad 500037, India
| | - Rajanna Rajeshwari
- Department of Plant Pathology, College of Horticulture, University of Horticultural Sciences, Bagalkot Campus, GKVK, Bengaluru 560064, India
| | - Jyotsnendu Giri
- Department of Biomedical Engineering, Indian Institute of Technology Hyderabad, Kandi, Sangareddy 502284, India
| | - Mehdi D. Davari
- Department of Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120 Halle, Germany
- Correspondence: (E.R.); (M.D.D.)
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Abstract
Bacterial cytochromes P450 BM3 (CYP450 BM3) catalyze reactions of industrial importance. Despite many successful biotransformations, robust (re)design for novel applications remains challenging. Rational design and evolutionary approaches are not always successful, highlighting a lack of complete understanding of the mechanisms of electron transfer (ET) modulations. Thus, the full potential of CYP450 reactions remains under-exploited. In this work, we report the first molecular dynamics (MD)-based explicit prediction of BM3 ET parameters (reorganization energies; λ and ET free energies; ΔG°), and log ET rates (log kET) using the Marcus theory. Overall, the calculated ET rates for the BM3 wild-type (WT), mutants (F393 and L86), ligand-bound state, and ion concentrations agree well with experimental data. In ligand-free (LF) BM3, mutations modulate kET via ET ΔG°. Simulations show that the experimental ET rate enhancement is due to increased driving force (more negative ΔG°) upon ligation. This increase is related to the protein reorganization required to accommodate the ligand in the binding pocket rather than binding interactions with the ligand. Our methodology (CYPWare 1.0) automates all the stages of the MD simulation step-up, energy calculations, and estimation of ET parameters. CYPWare 1.0 and this work thus represent an important advancement in the CYP450 ET rate predictions, which has the potential to guide the redesign of ET enzymes. This program and a Web tool are available on GitHub for academic research.
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Affiliation(s)
- Vaibhav A Dixit
- Department of Medicinal Chemistry, Department of Pharmaceuticals, Ministry of Chemicals & Fertilizers,, National Institute of Pharmaceutical Education and Research, Guwahati, (NIPER Guwahati) Govt. of India, Sila Katamur (Halugurisuk), P.O.: Changsari, Dist: Kamrup, 781101Guwahati, Assam, India
| | - Upadhyayula Suryanarayana Murty
- Department of Medicinal Chemistry, Department of Pharmaceuticals, Ministry of Chemicals & Fertilizers,, National Institute of Pharmaceutical Education and Research, Guwahati, (NIPER Guwahati) Govt. of India, Sila Katamur (Halugurisuk), P.O.: Changsari, Dist: Kamrup, 781101Guwahati, Assam, India
| | - Priyanka Bajaj
- National Institute of Pharmaceutical Education and Research, Hyderabad (NIPER Hyderabad), NH-9, Balanagar Main Road, Kukatpally Industrial Estate, Balanagar, Hyderabad500037, Telangana, India
| | - Jochen Blumberger
- Department of Physics and Astronomy, and Thomas Young Centre, University College London, Gower Street, LondonWC1E 6BT, U.K
| | - Sam P de Visser
- Manchester Institute of Biotechnology and Department of Chemical Engineering, The University of Manchester, 131 Princess Street, ManchesterM17DN, U.K
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Forster M, Krebs M, Majem M, Peguero J, Clay T, Felip E, Iams W, Roxburgh P, Doger B, Bajaj P, Kefas J, Scott J.A, Barba Joaquín A, Mueller C, Triebel F. EP08.01-109 TACTI-002: A Phase II Study of Eftilagimod Alpha (Soluble LAG-3) & Pembrolizumab in 2nd line PD-1/PD-L1 Refractory Metastatic NSCLC. J Thorac Oncol 2022. [DOI: 10.1016/j.jtho.2022.07.681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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9
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Bajaj P, Manjunath K, Varadarajan R. Structural and functional determinants inferred from deep mutational scans. Protein Sci 2022; 31:e4357. [PMID: 35762712 DOI: 10.1002/pro.4357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 04/04/2022] [Accepted: 05/11/2022] [Indexed: 11/08/2022]
Abstract
Mutations that affect protein binding to a cognate partner primarily occur either at buried residues or at exposed residues directly involved in partner binding. Distinguishing between these two categories based solely on mutational phenotypes is challenging. The bacterial toxin CcdB kills cells by binding to DNA Gyrase. Cell death is prevented by binding to its cognate antitoxin CcdA, at an extended interface that partially overlaps with the GyrA binding site. Using the CcdAB toxin-antitoxin (TA) system as a model, a comprehensive site-saturation mutagenesis library of CcdB was generated in its native operonic context. The mutational sensitivity of each mutant was estimated by evaluating the relative abundance of each mutant in two strains, one resistant and the other sensitive to the toxic activity of the CcdB toxin, through deep sequencing. The ability to bind CcdA was inferred through a RelE reporter gene assay, since the CcdAB complex binds to its own promoter, repressing transcription. By analyzing mutant phenotypes in the CcdB-sensitive, CcdB-resistant, and RelE reporter strains, it was possible to assign residues to buried, CcdA interacting or GyrA interacting sites. A few mutants were individually constructed, expressed, and biophysically characterized to validate molecular mechanisms responsible for the observed phenotypes. Residues inferred to be important for antitoxin binding, are also likely to be important for rejuvenating CcdB from the CcdB-Gyrase complex. Therefore, even in the absence of structural information, when coupled to appropriate genetic screens, such high-throughput strategies can be deployed for predicting structural and functional determinants of proteins.
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Affiliation(s)
- Priyanka Bajaj
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Kavyashree Manjunath
- Centre for Chemical Biology and Therapeutics, Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India
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Krebs M, Majem Tarruella M, Forster M, Peguero J, Clay T, Felip E, Iams W, Roxburgh P, Doger de Spéville B, Bajaj P, Mueller C, Triebel F. 11P Results of a phase II study investigating eftilagimod alpha (soluble LAG-3 protein) and pembrolizumab in second-line PD-1/PD-L1 refractory metastatic non-small cell lung carcinoma pts. Ann Oncol 2022. [DOI: 10.1016/j.annonc.2022.02.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Rajakumara E, Abhishek S, Nitin K, Saniya D, Bajaj P, Schwaneberg U, Davari MD. Structure and Cooperativity in Substrate-Enzyme Interactions: Perspectives on Enzyme Engineering and Inhibitor Design. ACS Chem Biol 2022; 17:266-280. [PMID: 35041385 DOI: 10.1021/acschembio.1c00500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Enzyme-based synthetic chemistry provides a green way to synthesize industrially important chemical scaffolds and provides incomparable substrate specificity and unmatched stereo-, regio-, and chemoselective product formation. However, using biocatalysts at an industrial scale has its challenges, like their narrow substrate scope, limited stability in large-scale one-pot reactions, and low expression levels. These limitations can be overcome by engineering and fine-tuning these biocatalysts using advanced protein engineering methods. A detailed understanding of the enzyme structure and catalytic mechanism and its structure-function relationship, cooperativity in binding of substrates, and dynamics of substrate-enzyme-cofactor complexes is essential for rational enzyme engineering for a specific purpose. This Review covers all these aspects along with an in-depth categorization of various industrially and pharmaceutically crucial bisubstrate enzymes based on their reaction mechanisms and their active site and substrate/cofactor-binding site structures. As the bisubstrate enzymes constitute around 60% of the known industrially important enzymes, studying their mechanism of actions and structure-activity relationship gives significant insight into deciding the targets for protein engineering for developing industrial biocatalysts. Thus, this Review is focused on providing a comprehensive knowledge of the bisubstrate enzymes' structure, their mechanisms, and protein engineering approaches to develop them into industrial biocatalysts.
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Affiliation(s)
- Eerappa Rajakumara
- Macromolecular Structural Biology Lab, Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana 502285, India
| | - Suman Abhishek
- Macromolecular Structural Biology Lab, Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana 502285, India
| | - Kulhar Nitin
- Macromolecular Structural Biology Lab, Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana 502285, India
| | - Dubey Saniya
- Macromolecular Structural Biology Lab, Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana 502285, India
| | - Priyanka Bajaj
- National Institute of Pharmaceutical Education and Research (NIPER), NH-44, Balanagar, Hyderabad 500037, India
| | - Ulrich Schwaneberg
- Institute of Biotechnology, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany
- DWI-Leibniz Institute for Interactive Materials, Forckenbeckstraße 50, 52074 Aachen, Germany
| | - Mehdi D. Davari
- Department of Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120 Halle, Germany
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Bajaj P, Khrapak S, Yaroshenko V, Schwabe M. Spatial distribution of dust density wave properties in fluid complex plasmas. Phys Rev E 2022; 105:025202. [PMID: 35291129 DOI: 10.1103/physreve.105.025202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 11/23/2021] [Indexed: 06/14/2023]
Abstract
Complex plasmas consist of microparticles embedded in a low-temperature plasma and allow investigating various effects by tracing the motion of these microparticles. Dust density waves appear in complex plasmas as self-excited acoustic waves in the microparticle fluid at low neutral gas pressures. Here we show that various properties of these waves depend on the position of the microparticle cloud with respect to the plasma sheath and explain this finding in terms of the underlying ion-drift instability. These results may be helpful in better understanding the propagation of dust density waves in complex plasmas and beyond, for instance, in astrophysical dusty plasmas.
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Affiliation(s)
- P Bajaj
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), D-82234 Weßling, Germany
| | - S Khrapak
- Joint Institute for High Temperatures, Russian Academy of Sciences, 125412 Moscow, Russia
| | - V Yaroshenko
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), D-82234 Weßling, Germany
| | - M Schwabe
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), D-82234 Weßling, Germany
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13
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Fountain J, Pandey A, Nayak S, Bajaj P, Wang H, Kumar V, Chitikineni A, Abbas H, Scully B, Kemerait R, Pandey M, Guo B, Varshney R. Transcriptional responses of toxigenic and atoxigenic isolates of Aspergillus flavus to oxidative stress in aflatoxin-conducive and non-conducive media. WORLD MYCOTOXIN J 2020. [DOI: 10.3920/wmj2020.2566] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Aflatoxin production by isolates of Aspergillus flavus varies, ranging from highly toxigenic to completely atoxigenic. Several mechanisms have been identified which regulate aflatoxin production including medium carbon source and oxidative stress. In recent studies, aflatoxin production has been implicated in partially ameliorating oxidative stress in A. flavus. To better understand the role of aflatoxin production in oxidative stress responses, a selection of toxigenic and atoxigenic isolates of A. flavus with moderate to high oxidative stress tolerance were exposed to increasing concentrations of H2O2 in both aflatoxin-conducive and non-conducive media. Mycelial mats were collected for global transcriptome sequencing followed by differential expression, functional prediction, and weighted co-expression analyses. Oxidative stress and medium carbon source had a significant effect on the expression of several secondary metabolite gene clusters including those for aflatoxin, aflatrem, aflavarin, cyclopiazonic acid, and kojic acid. Atoxigenic biological control isolates showed less differential expression under stress than other atoxigenic isolates suggesting expression profiles may be useful in screening. Increasing stress also resulted in regulation of SakA/Hog1 and MpkA MAP kinase signalling pathways pointing to their potential roles in regulating oxidative stress responses. Their expression was also influenced by medium carbon source. These results suggest that aflatoxin production along with that of other mycotoxins may occur as part of a concerted coping mechanism for oxidative stress and its effects in the environment. This mechanism is also regulated by availability of simple sugars and glycolytic compounds for their biosynthesis.
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Affiliation(s)
- J.C. Fountain
- USDA-ARS, Crop Protection and Management Research Unit, Tifton, GA 31793, USA
- Department of Plant Pathology, University of Georgia, Tifton, GA 31793, USA
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Starkville, MS 39762, USA
| | - A.K. Pandey
- Center of Excellence in Genomics & Systems Biology, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, Telangana 502324, India
| | - S.N. Nayak
- Department of Biotechnology, University of Agricultural Sciences, Dharwad, Karnataka 580005, India
| | - P. Bajaj
- Center of Excellence in Genomics & Systems Biology, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, Telangana 502324, India
| | - H. Wang
- Department of Plant Pathology, University of Georgia, Tifton, GA 31793, USA
| | - V. Kumar
- Center of Excellence in Genomics & Systems Biology, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, Telangana 502324, India
| | - A. Chitikineni
- Center of Excellence in Genomics & Systems Biology, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, Telangana 502324, India
| | - H.K. Abbas
- USDA-ARS, Biological Control of Pests Research Unit, Stoneville, MS, USA
| | - B.T. Scully
- USDA-ARS, National Horticultural Research Laboratory, Fort Pierce, FL, USA
| | - R.C. Kemerait
- Department of Plant Pathology, University of Georgia, Tifton, GA 31793, USA
| | - M.K. Pandey
- Center of Excellence in Genomics & Systems Biology, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, Telangana 502324, India
| | - B. Guo
- USDA-ARS, Crop Protection and Management Research Unit, Tifton, GA 31793, USA
| | - R.K. Varshney
- Center of Excellence in Genomics & Systems Biology, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, Telangana 502324, India
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14
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Fountain J, Pandey A, Nayak S, Bajaj P, Wang H, Kumar V, Chitikineni A, Abbas H, Scully B, Kemerait R, Pandey M, Guo B, Varshney R. Transcriptional responses of toxigenic and atoxigenic isolates of Aspergillus flavus to oxidative stress in aflatoxin-conducive and non-conducive media. WORLD MYCOTOXIN J 2020. [DOI: 10.3920/wmj2020.test2566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Aflatoxin production by isolates of Aspergillus flavus varies, ranging from highly toxigenic to completely atoxigenic. Several mechanisms have been identified which regulate aflatoxin production including medium carbon source and oxidative stress. In recent studies, aflatoxin production has been implicated in partially ameliorating oxidative stress in A. flavus. To better understand the role of aflatoxin production in oxidative stress responses, a selection of toxigenic and atoxigenic isolates of A. flavus with moderate to high oxidative stress tolerance were exposed to increasing concentrations of H2O2 in both aflatoxin-conducive and non-conducive media. Mycelial mats were collected for global transcriptome sequencing followed by differential expression, functional prediction, and weighted co-expression analyses. Oxidative stress and medium carbon source had a significant effect on the expression of several secondary metabolite gene clusters including those for aflatoxin, aflatrem, aflavarin, cyclopiazonic acid, and kojic acid. Atoxigenic biological control isolates showed less differential expression under stress than other atoxigenic isolates suggesting expression profiles may be useful in screening. Increasing stress also resulted in regulation of SakA/Hog1 and MpkA MAP kinase signalling pathways pointing to their potential roles in regulating oxidative stress responses. Their expression was also influenced by medium carbon source. These results suggest that aflatoxin production along with that of other mycotoxins may occur as part of a concerted coping mechanism for oxidative stress and its effects in the environment. This mechanism is also regulated by availability of simple sugars and glycolytic compounds for their biosynthesis.
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Affiliation(s)
- J.C. Fountain
- USDA-ARS, Crop Protection and Management Research Unit, Tifton, GA 31793, USA
- Department of Plant Pathology, University of Georgia, Tifton, GA 31793, USA
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Starkville, MS 39762, USA
| | - A.K. Pandey
- Center of Excellence in Genomics & Systems Biology, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, Telangana 502324, India
| | - S.N. Nayak
- Department of Biotechnology, University of Agricultural Sciences, Dharwad, Karnataka 580005, India
| | - P. Bajaj
- Center of Excellence in Genomics & Systems Biology, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, Telangana 502324, India
| | - H. Wang
- Department of Plant Pathology, University of Georgia, Tifton, GA 31793, USA
| | - V. Kumar
- Center of Excellence in Genomics & Systems Biology, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, Telangana 502324, India
| | - A. Chitikineni
- Center of Excellence in Genomics & Systems Biology, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, Telangana 502324, India
| | - H.K. Abbas
- USDA-ARS, Biological Control of Pests Research Unit, Stoneville, MS, USA
| | - B.T. Scully
- USDA-ARS, National Horticultural Research Laboratory, Fort Pierce, FL, USA
| | - R.C. Kemerait
- Department of Plant Pathology, University of Georgia, Tifton, GA 31793, USA
| | - M.K. Pandey
- Center of Excellence in Genomics & Systems Biology, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, Telangana 502324, India
| | - B. Guo
- USDA-ARS, Crop Protection and Management Research Unit, Tifton, GA 31793, USA
| | - R.K. Varshney
- Center of Excellence in Genomics & Systems Biology, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, Telangana 502324, India
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15
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Forster M, Felip E, Doger B, Lopez Pousa A, Carcereny E, Bajaj P, Church M, Peguero J, Roxburgh P, Triebel F. 927P Initial results from a phase II study (TACTI-002) of eftilagimod alpha (soluble LAG-3 protein) and pembrolizumab as 2nd line treatment for PD-L1 unselected metastatic head and neck cancer patients. Ann Oncol 2020. [DOI: 10.1016/j.annonc.2020.08.1042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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16
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Bajaj P, Mahajan R. Cellulase and xylanase synergism in industrial biotechnology. Appl Microbiol Biotechnol 2019; 103:8711-8724. [DOI: 10.1007/s00253-019-10146-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 09/10/2019] [Accepted: 09/17/2019] [Indexed: 11/29/2022]
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17
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Bajaj P, Roth J, Sullivan S, Stein A, Mahtani R, Ramsey S. Potential survival gains from first-line (1L) systemic therapy advances in metastatic triple-negative breast cancer (mTNBC). Ann Oncol 2018. [DOI: 10.1093/annonc/mdy272.337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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18
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Luhn T, Chui S, Hsieh A, Yi J, Mecke A, Bajaj P, Hasnain W, Falgas A, Ton T, Kurian A. Comparative effectiveness of nab-paclitaxel vs. paclitaxel monotherapy as first-line (1L) treatment of metastatic triple-negative breast cancer (mTNBC) in US clinical practice. Ann Oncol 2018. [DOI: 10.1093/annonc/mdy272.306] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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19
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Moore EJ, Steck V, Bajaj P, Fasan R. Chemoselective Cyclopropanation over Carbene Y-H Insertion Catalyzed by an Engineered Carbene Transferase. J Org Chem 2018; 83:7480-7490. [PMID: 29905476 DOI: 10.1021/acs.joc.8b00946] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hemoproteins have recently emerged as promising biocatalysts for promoting a variety of carbene transfer reactions including cyclopropanation and Y-H insertion (Y = N, S, Si, B). For these and synthetic carbene transfer catalysts alike, achieving high chemoselectivity toward cyclopropanation in olefin substrates bearing unprotected Y-H groups has proven remarkably challenging due to competition from the more facile carbene Y-H insertion reaction. In this report, we describe the development of a novel artificial metalloenzyme based on an engineered myoglobin incorporating a serine-ligated Co-porphyrin cofactor that is capable of offering high selectivity toward olefin cyclopropanation over N-H and Si-H insertion. Intramolecular competition experiments revealed a distinct and dramatically altered chemoselectivity of the Mb(H64V,V68A,H93S)[Co(ppIX)] variant in carbene transfer reactions compared to myoglobin-based variants containing the native histidine-ligated heme cofactor or other metal/proximal ligand substitutions. These studies highlight the functional plasticity of myoglobin as a "carbene transferase" and illustrate how modulation of the cofactor environment within this metalloprotein scaffold represents a valuable strategy for accessing carbene transfer reactivity not exhibited by naturally occurring hemoproteins or transition metal catalysts.
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Affiliation(s)
- Eric J Moore
- Department of Chemistry , University of Rochester , Rochester , New York 14627 , United States
| | - Viktoria Steck
- Department of Chemistry , University of Rochester , Rochester , New York 14627 , United States
| | - Priyanka Bajaj
- Department of Chemistry , University of Rochester , Rochester , New York 14627 , United States
| | - Rudi Fasan
- Department of Chemistry , University of Rochester , Rochester , New York 14627 , United States
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20
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Satram-Hoang S, Bajaj P, Stein A, Hoang K, Momin F, Cortazar P, Reyes C. Real-world treatment patterns and outcomes among elderly metastatic triple negative breast cancer patients in the United States. Ann Oncol 2017. [DOI: 10.1093/annonc/mdx365.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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21
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Roth J, Bajaj P, Sullivan S, Reyes C, Antao V, Stein A, Mahtani R, Ramsey S. Survival gains from advances in first-line systemic therapy for HER2-positive metastatic breast cancer in the U.S., 1995-2015. Ann Oncol 2017. [DOI: 10.1093/annonc/mdx365.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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22
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Bajaj P, Latremouille-Viau D, Guerin A, Reyes C, Stein A, Kurian A, Cortazar P. What are the treatment patterns and overall survival (OS) in patients with metastatic triple-negative breast cancer (mTNBC) in US clinical practice? Ann Oncol 2017. [DOI: 10.1093/annonc/mdx365.031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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23
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Bajaj P, Sreenilayam G, Tyagi V, Fasan R. Gram-Scale Synthesis of Chiral Cyclopropane-Containing Drugs and Drug Precursors with Engineered Myoglobin Catalysts Featuring Complementary Stereoselectivity. Angew Chem Int Ed Engl 2016; 55:16110-16114. [PMID: 27885768 PMCID: PMC5755974 DOI: 10.1002/anie.201608680] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 11/02/2016] [Indexed: 11/07/2022]
Abstract
Engineered hemoproteins have recently emerged as promising systems for promoting asymmetric cyclopropanations, but variants featuring predictable, complementary stereoselectivity in these reactions have remained elusive. In this study, a rationally driven strategy was implemented and applied to engineer myoglobin variants capable of providing access to 1-carboxy-2-aryl-cyclopropanes with high trans-(1R,2R) selectivity and catalytic activity. The stereoselectivity of these cyclopropanation biocatalysts complements that of trans-(1S,2S)-selective variants developed here and previously. In combination with whole-cell biotransformations, these stereocomplementary biocatalysts enabled the multigram synthesis of the chiral cyclopropane core of four drugs (Tranylcypromine, Tasimelteon, Ticagrelor, and a TRPV1 inhibitor) in high yield and with excellent diastereo- and enantioselectivity (98-99.9% de; 96-99.9% ee). These biocatalytic strategies outperform currently available methods to produce these drugs.
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Affiliation(s)
- Priyanka Bajaj
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, NY, 14627, USA
| | | | - Vikas Tyagi
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, NY, 14627, USA
| | - Rudi Fasan
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, NY, 14627, USA
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24
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Bajaj P, Sreenilayam G, Tyagi V, Fasan R. Gram-Scale Synthesis of Chiral Cyclopropane-Containing Drugs and Drug Precursors with Engineered Myoglobin Catalysts Featuring Complementary Stereoselectivity. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201608680] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Priyanka Bajaj
- Department of Chemistry; University of Rochester; 120 Trustee Road Rochester NY 14627 USA
| | | | - Vikas Tyagi
- Department of Chemistry; University of Rochester; 120 Trustee Road Rochester NY 14627 USA
| | - Rudi Fasan
- Department of Chemistry; University of Rochester; 120 Trustee Road Rochester NY 14627 USA
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25
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Tyagi V, Sreenilayam G, Bajaj P, Tinoco A, Fasan R. Biocatalytic Synthesis of Allylic and Allenyl Sulfides through a Myoglobin-Catalyzed Doyle-Kirmse Reaction. Angew Chem Int Ed Engl 2016; 55:13562-13566. [PMID: 27647732 PMCID: PMC5189672 DOI: 10.1002/anie.201607278] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Indexed: 11/11/2022]
Abstract
The first example of a biocatalytic [2,3]-sigmatropic rearrangement reaction involving allylic sulfides and diazo reagents (Doyle-Kirmse reaction) is reported. Engineered variants of sperm whale myoglobin catalyze this synthetically valuable C-C bond-forming transformation with high efficiency and product conversions across a variety of sulfide substrates (e.g., aryl-, benzyl-, and alkyl-substituted allylic sulfides) and α-diazo esters. Moreover, the scope of this myoglobin-mediated transformation could be extended to the conversion of propargylic sulfides to give substituted allenes. Active-site mutations proved effective in enhancing the catalytic efficiency of the hemoprotein in these reactions as well as modulating the enantioselectivity, resulting in the identification of the myoglobin variant Mb(L29S,H64V,V68F), which is capable of mediating asymmetric Doyle-Kirmse reactions with an enantiomeric excess up to 71 %. This work extends the toolbox of currently available biocatalytic strategies for the asymmetric formation of carbon-carbon bonds.
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Affiliation(s)
- Vikas Tyagi
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, NY, 14627, USA
| | | | - Priyanka Bajaj
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, NY, 14627, USA
| | - Antonio Tinoco
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, NY, 14627, USA
| | - Rudi Fasan
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, NY, 14627, USA.
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26
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Bansal S, Bajaj P, Pandey S, Tandon V. Topoisomerases: Resistance versus Sensitivity, How Far We Can Go? Med Res Rev 2016; 37:404-438. [PMID: 27687257 DOI: 10.1002/med.21417] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 08/04/2016] [Accepted: 08/29/2016] [Indexed: 12/15/2022]
Abstract
DNA topoisomerases are ubiquitously present remarkable molecular machines that help in altering topology of DNA in living cells. The crucial role played by these nucleases during DNA replication, transcription, and recombination vis-à-vis less sequence similarity among different species makes topoisomerases unique and attractive targets for different anticancer and antibacterial drugs. However, druggability of topoisomerases by the existing class of molecules is increasingly becoming questationable due to resistance development predominated by mutations in the corresponding genes. The current scenario facing a decline in the development of new molecules further comprises an important factor that may challenge topoisomerase-targeting therapy. Thus, it is imperative to wisely use the existing inhibitors lest with this rapid rate of losing grip over the target we may not go too far. Furthermore, it is important not only to design new molecules but also to develop new approaches that may avoid obstacles in therapies due to multiple resistance mechanisms. This review provides a succinct account of different classes of topoisomerase inhibitors, focuses on resistance acquired by mutations in topoisomerases, and discusses the various approaches to increase the efficacy of topoisomerase inhibitors. In a later section, we also suggest the possibility of using bisbenzimidazoles along with efflux pump inhibitors for synergistic bactericidal effects.
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Affiliation(s)
- Sandhya Bansal
- Dr. B.R. Ambedkar Center for Biomedical Research, University of Delhi, New Delhi, India
| | - Priyanka Bajaj
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
| | - Stuti Pandey
- Department of Chemistry, University of Delhi, New Delhi, India
| | - Vibha Tandon
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India.,Department of Chemistry, University of Delhi, New Delhi, India
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27
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Tyagi V, Sreenilayam G, Bajaj P, Tinoco A, Fasan R. Biocatalytic Synthesis of Allylic and Allenyl Sulfides through a Myoglobin-Catalyzed Doyle-Kirmse Reaction. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201607278] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Vikas Tyagi
- Department of Chemistry; University of Rochester; 120 Trustee Road Rochester NY 14627 USA
| | | | - Priyanka Bajaj
- Department of Chemistry; University of Rochester; 120 Trustee Road Rochester NY 14627 USA
| | - Antonio Tinoco
- Department of Chemistry; University of Rochester; 120 Trustee Road Rochester NY 14627 USA
| | - Rudi Fasan
- Department of Chemistry; University of Rochester; 120 Trustee Road Rochester NY 14627 USA
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28
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Abstract
Escherichia coli strains belonging to diverse pathotypes have increasingly been recognized as a major public health concern. The β-lactam antibiotics have been used successfully to treat infections caused by pathogenic E. coli. However, currently, the utility of β-lactams is being challenged severely by a large number of hydrolytic enzymes – the β-lactamases expressed by bacteria. The menace is further compounded by the highly flexible genome of E. coli, and propensity of resistance dissemination through horizontal gene transfer and clonal spread. Successful management of infections caused by such resistant strains requires an understanding of the diversity of β-lactamases, their unambiguous detection, and molecular mechanisms underlying their expression and spread with regard to the most relevant information about individual bacterial species. Thus, this review comprises first such effort in this direction for E. coli, a bacterial species known to be associated with production of diverse classes of β-lactamases. The review also highlights the role of commensal E. coli as a potential but under-estimated reservoir of β-lactamases-encoding genes.
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Affiliation(s)
- Priyanka Bajaj
- Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus New Delhi, India
| | - Nambram S Singh
- Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus New Delhi, India
| | - Jugsharan S Virdi
- Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus New Delhi, India
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29
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Aggarwal G, Prajapati R, Tripathy RK, Bajaj P, Iyengar ARS, Sangamwar AT, Pande AH. Toward Understanding the Catalytic Mechanism of Human Paraoxonase 1: Site-Specific Mutagenesis at Position 192. PLoS One 2016; 11:e0147999. [PMID: 26829396 PMCID: PMC4734699 DOI: 10.1371/journal.pone.0147999] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Accepted: 01/10/2016] [Indexed: 01/02/2023] Open
Abstract
Human paraoxonase 1 (h-PON1) is a serum enzyme that can hydrolyze a variety of substrates. The enzyme exhibits anti-inflammatory, anti-oxidative, anti-atherogenic, anti-diabetic, anti-microbial and organophosphate-hydrolyzing activities. Thus, h-PON1 is a strong candidate for the development of therapeutic intervention against a variety conditions in human. However, the crystal structure of h-PON1 is not solved and the molecular details of how the enzyme hydrolyzes different substrates are not clear yet. Understanding the catalytic mechanism(s) of h-PON1 is important in developing the enzyme for therapeutic use. Literature suggests that R/Q polymorphism at position 192 in h-PON1 dramatically modulates the substrate specificity of the enzyme. In order to understand the role of the amino acid residue at position 192 of h-PON1 in its various hydrolytic activities, site-specific mutagenesis at position 192 was done in this study. The mutant enzymes were produced using Escherichia coli expression system and their hydrolytic activities were compared against a panel of substrates. Molecular dynamics simulation studies were employed on selected recombinant h-PON1 (rh-PON1) mutants to understand the effect of amino acid substitutions at position 192 on the structural features of the active site of the enzyme. Our results suggest that, depending on the type of substrate, presence of a particular amino acid residue at position 192 differentially alters the micro-environment of the active site of the enzyme resulting in the engagement of different subsets of amino acid residues in the binding and the processing of substrates. The result advances our understanding of the catalytic mechanism of h-PON1.
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Affiliation(s)
- Geetika Aggarwal
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar (Mohali) -160062, Punjab, India
| | - Rameshwar Prajapati
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar (Mohali) -160062, Punjab, India
| | - Rajan K. Tripathy
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar (Mohali) -160062, Punjab, India
| | - Priyanka Bajaj
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar (Mohali) -160062, Punjab, India
| | - A. R. Satvik Iyengar
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar (Mohali) -160062, Punjab, India
| | - Abhay T. Sangamwar
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar (Mohali) -160062, Punjab, India
| | - Abhay H. Pande
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar (Mohali) -160062, Punjab, India
- * E-mail:
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30
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Bajaj P, Kanaujia PK, Singh NS, Sharma S, Kumar S, Virdi JS. Quinolone co-resistance in ESBL- or AmpC-producing Escherichia coli from an Indian urban aquatic environment and their public health implications. Environ Sci Pollut Res Int 2016; 23:1954-1959. [PMID: 26498967 DOI: 10.1007/s11356-015-5609-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 10/13/2015] [Indexed: 06/05/2023]
Abstract
Quinolone and β-lactam antibiotics constitute major mainstay of treatment against infections caused by pathogenic Escherichia coli. Presence of E. coli strains expressing co-resistance to both these antibiotic classes in urban aquatic environments which are consistently being used for various anthropogenic activities represents a serious public health concern. From a heterogeneous collection of 61 E. coli strains isolated from the river Yamuna traversing through the National Capital Territory of Delhi (India), those harboring blaCTX-M-15 (n = 10) or blaCMY-42 (n = 2) were investigated for co-resistance to quinolones and the molecular mechanisms thereof. Resistance was primarily attributed to amino acid substitutions in the quinolone resistance-determining regions (QRDRs) of GyrA (S83L ± D87N) and ParC (S80I ± E84K). One of the E. coli strains, viz., IPE, also carried substitutions in GyrB and ParE at positions Ser492→Asn and Ser458→Ala, respectively. The phenotypically susceptible strains nevertheless carried plasmid-mediated quinolone resistance (PMQR) gene, viz., qnrS, which showed co-transfer to the recipient quinolone-sensitive E. coli J53 along with the genes encoding β-lactamases and led to increase in minimal inhibitory concentrations of quinolone antibiotics. To the best of our knowledge, this represents first report of molecular characterization of quinolone co-resistance in E. coli harboring genes for ESBLs or AmpC β-lactamases from a natural aquatic environment of India. The study warrants true appreciation of the potential of urban aquatic environments in the emergence and spread of multi-drug resistance and underscores the need to characterize resistance genetic elements vis-à-vis their public health implications, irrespective of apparent phenotypic resistance.
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Affiliation(s)
- Priyanka Bajaj
- Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Pawan Kumar Kanaujia
- Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Nambram Somendro Singh
- Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Shalu Sharma
- Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Shakti Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India
| | - Jugsharan Singh Virdi
- Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India.
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31
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Parikh H, Bajaj P, Tripathy R, Pande A. Improving Properties of Recombinant SsoPox by Site-Specific Pegylation. Protein Pept Lett 2015; 22:1098-103. [DOI: 10.2174/0929866522666151002122751] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 09/28/2015] [Accepted: 09/30/2015] [Indexed: 11/22/2022]
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32
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Kanaujia PK, Bajaj P, Virdi JS. Analysis of iron acquisition and storage-related genes in clinical and non-clinical strains of Yersinia enterocolitica biovar 1A. APMIS 2015. [PMID: 26223204 DOI: 10.1111/apm.12425] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Possession of mechanisms for iron acquisition and its storage enhances the ability of the bacteria to survive in the iron-limiting environment of the host. In this study, 81 strains of Yersinia enterocolitica biovar 1A isolated from various clinical (n = 51) and non-clinical (n = 30) sources were investigated for the presence of the genes related to iron acquisition and storage. Important genes which were present in more than 85% of the strains included hasA, foxA, bfr, bfd, ftnA, and hmsT as well as the fhuCDB, fepBDGCfesfepA, feoAB, yfuABCD, hemPRSTUV, and hmsHFRS gene clusters. Majority of these genes is being reported for the first time in biovar 1A strains and showed significant homology with genes present in the known pathogenic biovars of Y. enterocolitica. However, no significant difference was observed in the distribution of iron acquisition and storage-related genes among clinical and non-clinical biovar 1A strains. Thus, it may be suggested that the presence of iron acquisition and storage-related genes per se might not be responsible for the supposedly better ability of clinical biovar 1A strains to cause infections in humans. However, in the backdrop of this data, the need to undertake functional studies are highly recommended.
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Affiliation(s)
- Pawan Kumar Kanaujia
- Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus, New Delhi, India
| | - Priyanka Bajaj
- Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus, New Delhi, India
| | - Jugsharan Singh Virdi
- Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus, New Delhi, India
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Satvik Iyengar A, Tripathy RK, Bajaj P, Pande AH. Improving storage stability of recombinant organophosphorus hydrolase. Protein Expr Purif 2015; 111:28-35. [DOI: 10.1016/j.pep.2015.01.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Accepted: 01/30/2015] [Indexed: 11/16/2022]
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Kanaujia PK, Bajaj P, Kumar S, Singhal N, Virdi JS. Proteomic analysis of Yersinia enterocolitica biovar 1A under iron-rich and iron-poor conditions indicate existence of efficiently regulated mechanisms of iron homeostasis. J Proteomics 2015; 124:39-49. [PMID: 25913300 DOI: 10.1016/j.jprot.2015.04.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2015] [Revised: 03/30/2015] [Accepted: 04/13/2015] [Indexed: 01/30/2023]
Abstract
UNLABELLED The pathogenicity of Yersinia enterocolitica biovar 1A strains is controversial as these lack most of the known virulence factors. Acquisition of iron and presence of well-regulated iron homeostasis in bacteria represents an important virulence trait. Differential abundance of proteins was examined under iron-rich and iron-poor conditions in a clinical Y. enterocolitica biovar 1A strain IP27407. Whole cell protein profiles were analysed by 2D gel electrophoresis (2D-GE). Following statistical and MALDI-TOF MS analyses, 28 differentially abundant proteins were identified. Significant iron-responsive changes were observed in the proteins involved in iron acquisition or storage namely, hemin receptor (HemR), periplasmic Fe(2+) transport protein (Tpd), periplasmic chelated iron-binding protein (YfeA) and bacterioferritin (Bfr). Quantitative real-time PCR (qRT-PCR) of eight mRNA transcripts revalidated the differential protein abundance. In silico analysis of iron homeostasis mediated by the bacterioferritin and bacterioferritin-associated ferredoxin (Bfr-Bfd) complex suggested two pathways for the release of reserve iron which might be operating under conditions of different iron availability. The study, for the first time, showed the existence of highly competent iron homeostasis mechanisms in Y. enterocolitica biovar 1A and identified the key proteins involved thereof. Such mechanisms might have implications for the pathogenicity of Y. enterocolitica biovar 1A strains. BIOLOGICAL SIGNIFICANCE Although, a few studies have identified the differentially abundant bacterial proteins in response to iron starvation, little information is available in this regard for Y. enterocolitica (especially, the biovar 1A strains). In the present study, differential abundance of several proteins was identified under iron-rich and iron-poor conditions by 2D-GE and MALDI-TOF/MS analysis. These included proteins which may not only be directly implicated in iron acquisition or storage but also play crucial role in cellular metabolism. Given the absence of most known virulence factors in Y. enterocolitica biovar 1A strains, demonstration of well-regulated mechanisms for efficient iron homeostasis constitutes an important observation. The proteins, as identified in the present study, provide useful insights to further unravel the potential pathogenicity of the biovar 1A strains.
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Affiliation(s)
- Pawan Kumar Kanaujia
- Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi 110 021, India.
| | - Priyanka Bajaj
- Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi 110 021, India.
| | - Shakti Kumar
- Parasitology Laboratory, Department of Zoology, North-Eastern Hill University, Shillong 793022, India.
| | - Neelja Singhal
- Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi 110 021, India.
| | - Jugsharan Singh Virdi
- Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi 110 021, India.
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Bajaj P, Singh NS, Kanaujia PK, Virdi JS. Distribution and molecular characterization of genes encoding CTX-M and AmpC β-lactamases in Escherichia coli isolated from an Indian urban aquatic environment. Sci Total Environ 2015; 505:350-6. [PMID: 25461036 DOI: 10.1016/j.scitotenv.2014.09.084] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 08/14/2014] [Accepted: 09/25/2014] [Indexed: 05/21/2023]
Abstract
Aquatic environments harboring antibiotic resistant Escherichia coli constitute an important public health concern. Thus, it is important to characterize the resistance genetic elements of waterborne E. coli. It is also important to identify the predominant clonal groups/phylogroups represented by resistant strains to understand the epidemiology of antibiotic resistant E. coli in natural environments, and to identify the role of well-established genotypes in the spread of resistance in a particular geographical area through natural environments. In the present investigation, E. coli strains (n=126) isolated from various points along the river Yamuna traversing through the National Capital Territory of Delhi (India) were grouped phylogenetically. A collection of 61 strains representing all phylogroups was investigated for extended-spectrum β-lactamase (ESBL) and AmpC production. blaTEM, blaSHV and blaCTX-M genes were detected and analyzed, promoter/attenuator mutations associated with chromosomally-mediated AmpC overexpression were identified, and plasmid-mediated ampC was determined. blaTEM was the most widespread (100%) gene followed by bla(CTX-M) (16%), and plasmid-mediated ampC (3%). bla(CTX-M-15) and bla(CMY-42) were identified as the genes encoding CTX-M type ESBL and CIT type AmpC β-lactamases, respectively. CTX-M-15 ESBL phenotype was most common in phylogroup D (50%), followed by phylogroups B1 (30%), and A (20%). E. coli that produce plasmid-mediated AmpC were rare and present only in phylogroup D. Presence of multi β-lactam resistance, bla(CTX-M-15) and bla(CMY-42) in waterborne E. coli belonging to virulence-associated phylogroup D highlights the need for routine surveillance of resistance determinants in aquatic environments. This is also the first report for the presence of bla(CMY-42) in waterborne E. coli.
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Affiliation(s)
- Priyanka Bajaj
- Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India
| | - Nambram Somendro Singh
- Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India
| | - Pawan Kumar Kanaujia
- Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India
| | - Jugsharan Singh Virdi
- Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India.
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Bajaj P, Aggarwal G, Tripathy RK, Pande AH. Interplay between amino acid residues at positions 192 and 115 in modulating hydrolytic activities of human paraoxonase 1. Biochimie 2014; 105:202-10. [DOI: 10.1016/j.biochi.2014.07.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 07/29/2014] [Indexed: 11/28/2022]
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Nimesh H, Sur S, Sinha D, Yadav P, Anand P, Bajaj P, Virdi JS, Tandon V. Synthesis and Biological Evaluation of Novel Bisbenzimidazoles as Escherichia coli Topoisomerase IA Inhibitors and Potential Antibacterial Agents. J Med Chem 2014; 57:5238-57. [DOI: 10.1021/jm5003028] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Hemlata Nimesh
- Department
of Chemistry, University of Delhi, Delhi 110 007, India
| | - Souvik Sur
- Department
of Chemistry, University of Delhi, Delhi 110 007, India
| | - Devapriya Sinha
- Department
of Chemistry, University of Delhi, Delhi 110 007, India
| | - Pooja Yadav
- Department
of Chemistry, University of Delhi, Delhi 110 007, India
| | - Prachi Anand
- Department of Chemistry & Biochemistry, CUNY−Hunter College, New York, New York 10065, United States
| | - Priyanka Bajaj
- Department
of Microbiology, University of Delhi, Delhi 110 021, India
| | | | - Vibha Tandon
- Department
of Chemistry, University of Delhi, Delhi 110 007, India
- Special
Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110 067, India
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Rao NS, Pradeep AR, Bajaj P, Kumari M, Naik SB. Simvastatin local drug delivery in smokers with chronic periodontitis: a randomized controlled clinical trial. Aust Dent J 2014; 58:156-62. [PMID: 23713634 DOI: 10.1111/adj.12042] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/22/2012] [Indexed: 11/28/2022]
Abstract
BACKGROUND Simvastatin (SMV) is a specific competitive inhibitor of 3-hydroxy-2-methyl-glutaryl coenzyme A reductase. Statins have recently been shown to promote bone formation. This study was designed to investigate the effectiveness of SMV 1.2% in an indigenously prepared biodegradable controlled release gel as an adjunct to scaling and root planing (SRP) in the treatment of smokers with chronic periodontitis. METHODS Forty patients were categorized into two treatment groups: SRP plus SMV 1.2% and SRP plus placebo. Clinical parameters were recorded at baseline and at 3, 6 and 9 months; they included modified sulcus bleeding index (mSBI), probing depth (PD) and clinical attachment level (CAL). At baseline, after 6 months and 9 months, radiologic assessment of intrabony defect (IBD) fill was done using computer-aided software. RESULTS Mean probing depth reduction and mean clinical attachment level gain was greater in the SMV group than the placebo group at all visits. Furthermore, significantly greater mean percentage of bone fill was found in the SMV group (32.37 ± 10.23%) compared to the placebo (4.18 ± 5.39%). CONCLUSIONS There was a greater decrease in mSBI and PD and more CAL gain with significant IBD fill at sites treated with SRP plus locally delivered SMV in smokers with chronic periodontitis.
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Affiliation(s)
- N S Rao
- Department of Periodontics, Government Dental College and Research Institute, Bangalore, India
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Kar S, Patel MA, Tripathy RK, Bajaj P, Pande AH. Oxidized-phospholipids in reconstituted high density lipoprotein particles affect structure and function of recombinant paraoxonase 1. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:1714-20. [DOI: 10.1016/j.bbalip.2013.08.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 07/31/2013] [Accepted: 08/07/2013] [Indexed: 11/25/2022]
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Bajaj P, Tripathy RK, Aggarwal G, Pande AH. Characterization of human paraoxonase 1 variants suggest that His residues at 115 and 134 positions are not always needed for the lactonase/arylesterase activities of the enzyme. Protein Sci 2013; 22:1799-807. [PMID: 24123308 DOI: 10.1002/pro.2380] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 09/21/2013] [Accepted: 09/23/2013] [Indexed: 12/12/2022]
Abstract
Human paraoxonase 1 (h-PON1) hydrolyzes variety of substrates and the hydrolytic activities of enzyme can be broadly grouped into three categories; arylesterase, phosphotriesterase, and lactonase. Current models of the catalytic mechanism of h-PON1 suggest that catalytic residues H115 and H134 mediate the lactonase and arylesterase activities of the enzyme. H-PON1 is a strong candidate for the development of catalytic bioscavenger for organophosphate poisoning in humans. Recently, Gupta et al. (Nat. Chem. Biol. 2011. 7, 120) identified amino acid substitutions that significantly increased the activity of chimeric-PON1 variant (4E9) against some organophosphate nerve agents. In this study we have examined the effect of these (L69G/S111T/H115W/H134R/R192K/F222S/T332S) and other substitutions (H115W/H134R and H115W/H134R/R192K) on the hydrolytic activities of recombinant h-PON1 (rh-PON1) variants. Our results show that the substitutions resulted in a significant increase in the organophosphatase activity of all the three variants of rh-PON1 enzyme while had a variable effect on the lactonase/arylesterase activities. The results suggest that H residues at positions 115 and 134 are not always needed for the lactonase/arylesterase activities of h-PON1 and force a reconsideration of the current model(s) of the catalytic mechanism of h-PON1.
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Affiliation(s)
- Priyanka Bajaj
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar (Mohali) 160062, Punjab, India
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Nankar SA, Bajaj P, Sravanthi R, Pande AH. Differential interaction of peptides derived from C-terminal domain of human apolipoprotein E with platelet activating factor analogs. Biochimie 2013; 95:1196-207. [DOI: 10.1016/j.biochi.2013.01.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 01/16/2013] [Indexed: 11/25/2022]
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Pradeep AR, Agarwal E, Bajaj P, Naik SB, Shanbhag N, Uma SR. Clinical and microbiologic effects of commercially available gel and powder containing Acacia arabica on gingivitis. Aust Dent J 2013; 57:312-8. [PMID: 22924354 DOI: 10.1111/j.1834-7819.2012.01714.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND There is a need for an anti-plaque agent that can be used on a daily basis without the side effects of antibacterial chemicals such as chlorhexidine. The present study was designed to evaluate the clinical and microbiologic effects of commercially available gel and powder containing Acacia arabica in subjects with gingivitis. METHODS One hundred and twenty subjects with chronic generalized gingivitis were selected and randomly divided into four groups: Group 1 - placebo group; Group 2 -Acacia arabica gel group; Group 3 -Acacia arabica powder group; and Group 4 - 1% chlorhexidine gel group. Microbial counts of plaque samples, the gingival index of Loe and Silness and the plaque index were evaluated at baseline, 6 weeks, 12 weeks and 24 weeks. Microbial counts of plaque samples were evaluated at all visits. RESULTS Acacia arabica gel and powder showed significant clinical improvement in gingival and plaque index scores as compared to a placebo. This improvement was comparable to 1% chlorhexidine gel. The difference between gel and powder with regard to clinical and microbiological parameters was not found to be significant at any time interval. CONCLUSIONS Both Acacia arabica gel and powder may be useful herbal formulations for chemical plaque control in subjects with gingivitis.
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Affiliation(s)
- A R Pradeep
- Department of Periodontics, Government Dental College and Research Institute, Bangalore, Karnataka, India.
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Pradeep AR, Bajaj P, Agarwal E, Rao NS, Naik SB, Kalra N, Priyanka N, Priyanaka N. Local drug delivery of 0.5% azithromycin in the treatment of chronic periodontitis among smokers. Aust Dent J 2013; 58:34-40. [PMID: 23441790 DOI: 10.1111/adj.12019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/18/2012] [Indexed: 11/28/2022]
Abstract
BACKGROUND Along with conventional periodontal surgical therapy, local delivery of antibiotics may provide more effective treatment in smokers by targeting tissue-invasive bacteria. The aim of this randomized, placebo-controlled, double-masked clinical trial was to evaluate the adjunctive effects of subgingivally delivered 0.5% azithromycin (AZM) as an adjunct to scaling and root planing (SRP) in the treatment of chronic periodontitis in smokers. METHODS Fifty-four patients were randomized and categorized into two treatment groups: Group 1 - 26 subjects who received (SRP) plus placebo gel and Group 2 - 28 subjects who received (SRP) plus 0.5% azithromycin. Clinical parameters were recorded at baseline, 3, 6 and 9 months. They included Plaque Index (PI), modified Sulcus Bleeding Index (mSBI), probing depth (PD) and clinical attachment level (CAL). RESULTS Azithromycin resulted in significant improvements. A single application of AZM resulted in attachment gain at 9 months of 2.44 ± 0.64 mm as compared to 0.18 ± 0.68 mm for the placebo. Similarly, pocket depth and PI were significantly reduced but no change in the mSBI was noted. CONCLUSIONS When compared to the placebo, the adjunctive use of 0.5% AZM resulted in significant improvement in clinical outcome in the treatment of chronic periodontitis among smokers.
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Affiliation(s)
- A R Pradeep
- Department of Periodontics, Government Dental College and Research Institute, Bangalore, India.
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Pradeep AR, Agarwal E, Naik SB, Bajaj P, Kalra N. Comparison of efficacy of three commercially available dentifrices on dentinal hypersensitivity: a randomized clinical trial. Aust Dent J 2012. [DOI: 10.1111/j.1834-7819.2012.01726.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Kar S, Patel MA, Tripathy RK, Bajaj P, Suvarnakar UV, Pande AH. Oxidized phospholipid content destabilizes the structure of reconstituted high density lipoprotein particles and changes their function. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1821:1200-10. [PMID: 22634518 DOI: 10.1016/j.bbalip.2012.05.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2012] [Revised: 05/02/2012] [Accepted: 05/11/2012] [Indexed: 11/16/2022]
Abstract
High density lipoprotein (HDL) particles are made up of lipid and protein constituents and apolipoprotein A-I (apoA-I) is a principal protein component that facilitates various biological activities of HDL particles. Increase in Ox-PL content of HDL particles makes them 'dysfunctional' and such modified HDL particles not only lose their athero-protective properties but also acquire pro-atherogenic and pro-inflammatory functions. The details of Ox-PL-induced alteration in the molecular properties of HDL particles are not clear. Paraoxonase 1 (PON1) is an HDL-associated enzyme that possesses anti-inflammatory and anti-atherogenic properties; and many of the athero-protective functions of HDL are attributed to the associated PON1. In this study we have characterized the physicochemical properties of reconstituted HDL (rHDL) particles containing varying amounts of Ox-PL and have compared their PON1 stimulation capacity. Our results show that increased Ox-PL content (a) modifies the physicochemical properties of the lipid domain of the rHDL particles, (b) decreases the stability and alters the conformation as well as orientation of apoA-I molecules on the rHDL particles, and (c) decreases the PON1 stimulation capacity of the rHDL particles. Our data indicate that the presence of Ox-PLs destabilizes the structure of the HDL particles and modifies their function.
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Affiliation(s)
- Subhabrata Kar
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Punjab, India
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Abstract
Transposition is a dental anomaly manifested by a positional interchange of two permanent teeth. The maxillary permanent canine usually transposes with the first premolar and occasionally with the lateral incisor. These are mainly genetically governed and are treated orthodontically if complete segment of tooth is present; in case of missing teeth, participation of cosmetic dentist is must. The present case report describes a situation where left canine to lateral incisor complete transposition was present along with a missing left central incisor. Esthetic rehabilitation of the "smile zone" was the major concern. Scrupulous treatment planning to esthetically contour transposed teeth according to their normal positions, i.e., transposed left canine to lateral incisor and transposed left lateral incisor to canine with replacement of missing tooth, was a challenge.
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Affiliation(s)
- S Yadav
- Department of Prosthodontics, Prabhu Dayal Memorial Dental College and Hospital, Bahadurgarh, Haryana, India.
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Bajaj P, Sheerer C, Donato A. Does Presence of Nasal Congestion Influence Patient's Choice of Delivery Interface for Continuous Positive Airway Pressure Therapy? J Allergy Clin Immunol 2012. [DOI: 10.1016/j.jaci.2011.12.550] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Mittal V, Kulshrestha R, Arya A, Bajaj P. Acute fibrinous and organising pneumonia presenting as complete lung consolidation. Singapore Med J 2011; 52:e88-e90. [PMID: 21633758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Acute fibrinous and organising pneumonia (AFOP) is an unusual histopathological pattern of acute lung injury. The clinical manifestations, course and treatment of AFOP have yet to be characterised. All reported cases so far have described bilateral diffuse lung involvement radiologically. We report a case of an adolescent girl who presented with acute hypoxaemic respiratory failure with unilateral complete lung consolidation. She was initially diagnosed with severe community-acquired pneumonia. A computed tomography-guided percutaneous transthoracic trucut biopsy of the left lung revealed the classical histopathological pattern typically observed in AFOP. The patient responded well to treatment involving steroids. The uniqueness of such a presentation in AFOP prompted us to report this case.
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Affiliation(s)
- V Mittal
- Department of Respiratory Medicine, Sri Balaji Action Medical Institute, Delhi 110063, India.
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Zazzali J, Bajaj P, Chen J, Tian H. Economic Burden of Asthma in a Commercially Insured Population. J Allergy Clin Immunol 2011. [DOI: 10.1016/j.jaci.2010.12.299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Juneja D, Singh O, Singh G, Bajaj P. Incidence of bacteremia at the time of ICU admission and its impact on outcome. Crit Care 2010. [PMCID: PMC3254959 DOI: 10.1186/cc9144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
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