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Joshi D, Patel H, Suthar S, Patel DH, Kikani BA. Evaluation of the efficiency of thermostable L-asparaginase from B. licheniformis UDS-5 for acrylamide mitigation during preparation of French fries. World J Microbiol Biotechnol 2024; 40:92. [PMID: 38345704 DOI: 10.1007/s11274-024-03907-1] [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: 09/29/2023] [Accepted: 01/23/2024] [Indexed: 02/15/2024]
Abstract
A thermostable L-asparaginase was produced from Bacillus licheniformis UDS-5 (GenBank accession number, OP117154). The production conditions were optimized by the Plackett Burman method, followed by the Box Behnken method, where the enzyme production was enhanced up to fourfold. It secreted L-asparaginase optimally in the medium, pH 7, containing 0.5% (w/v) peptone, 1% (w/v) sodium chloride, 0.15% (w/v) beef extract, 0.15% (w/v) yeast extract, 3% (w/v) L-asparagine at 50 °C for 96 h. The enzyme, with a molecular weight of 85 kDa, was purified by ion exchange chromatography and size exclusion chromatography with better purification fold and percent yield. It displayed optimal catalysis at 70 °C in 20 mM Tris-Cl buffer, pH 8. The purified enzyme also exhibited significant salt tolerance too, making it a suitable candidate for the food application. The L-asparaginase was employed at different doses to evaluate its ability to mitigate acrylamide, while preparing French fries without any prior treatment. The salient attributes of B. licheniformis UDS-5 L-asparaginase, such as greater thermal stability, salt stability and acrylamide reduction in starchy foods, highlights its possible application in the food industry.
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Affiliation(s)
- Disha Joshi
- Department of Biological Sciences, P. D. Patel Institute of Applied Sciences, Charotar University of Science and Technology, CHARUSAT Campus, Changa, Gujarat, 388 421, India
| | - Harsh Patel
- Department of Biological Sciences, P. D. Patel Institute of Applied Sciences, Charotar University of Science and Technology, CHARUSAT Campus, Changa, Gujarat, 388 421, India
| | - Sadikhusain Suthar
- Department of Biological Sciences, P. D. Patel Institute of Applied Sciences, Charotar University of Science and Technology, CHARUSAT Campus, Changa, Gujarat, 388 421, India
| | - Darshan H Patel
- Department of Biological Sciences, P. D. Patel Institute of Applied Sciences, Charotar University of Science and Technology, CHARUSAT Campus, Changa, Gujarat, 388 421, India.
| | - Bhavtosh A Kikani
- Department of Biological Sciences, P. D. Patel Institute of Applied Sciences, Charotar University of Science and Technology, CHARUSAT Campus, Changa, Gujarat, 388 421, India.
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Mali H, Shah C, Raghunandan BH, Prajapati AS, Patel DH, Trivedi U, Subramanian RB. Organophosphate pesticides an emerging environmental contaminant: Pollution, toxicity, bioremediation progress, and remaining challenges. J Environ Sci (China) 2023; 127:234-250. [PMID: 36522056 DOI: 10.1016/j.jes.2022.04.023] [Citation(s) in RCA: 53] [Impact Index Per Article: 53.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 04/19/2022] [Accepted: 04/19/2022] [Indexed: 06/17/2023]
Abstract
Organophosphates (OPs) are an integral part of modern agriculture; however, due to overexploitation, OPs pesticides residues are leaching and accumulating in the soil, and groundwater contaminated terrestrial and aquatic food webs. Acute exposure to OPs could produce toxicity in insects, plants, animals, and humans. OPs are known for covalent inhibition of acetylcholinesterase enzyme in pests and terrestrial/aquatic organisms, leading to nervous, respiratory, reproductive, and hepatic abnormalities. OPs pesticides also disrupt the growth-promoting machinery in plants by inhibiting key enzymes, permeability, and trans-cuticular diffusion, which is crucial for plant growth. Excessive use of OPs, directly/indirectly affecting human/environmental health, raise a thoughtful global concern. Developing a safe, reliable, economical, and eco-friendly methods for removing OPs pesticides from the environment is thus necessary. Bioremediation techniques coupled with microbes or microbial-biocatalysts are emerging as promising antidotes for OPs pesticides. Here, we comprehensively review the current scenario of OPs pollution, their toxicity (at a molecular level), and the recent advancements in biotechnology (modified biocatalytic systems) for detection, decontamination, and bioremediation of OP-pesticides in polluted environments. Furthermore, the review focuses on onsite applications of OPs degrading enzymes (immobilizations/biosensors/others), and it also highlights remaining challenges with future approaches.
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Affiliation(s)
- Himanshu Mali
- P. G. Department of Biosciences, UGC-Centre of Advanced Studies, Satellite Campus, Sardar Patel University, Sardar Patel Maidan, Bakrol-Vadtal Road, Bakrol 388 315, Gujarat, India
| | - Chandni Shah
- P. G. Department of Biosciences, UGC-Centre of Advanced Studies, Satellite Campus, Sardar Patel University, Sardar Patel Maidan, Bakrol-Vadtal Road, Bakrol 388 315, Gujarat, India
| | - B H Raghunandan
- P. G. Department of Biosciences, UGC-Centre of Advanced Studies, Satellite Campus, Sardar Patel University, Sardar Patel Maidan, Bakrol-Vadtal Road, Bakrol 388 315, Gujarat, India
| | - Anil S Prajapati
- P. G. Department of Biosciences, UGC-Centre of Advanced Studies, Satellite Campus, Sardar Patel University, Sardar Patel Maidan, Bakrol-Vadtal Road, Bakrol 388 315, Gujarat, India
| | - Darshan H Patel
- Charotar Institute of Paramedical Sciences, Charotar University of Science and Technology, (CHARUSAT), Changa 388421, Gujarat, India
| | - Ujjval Trivedi
- P. G. Department of Biosciences, UGC-Centre of Advanced Studies, Satellite Campus, Sardar Patel University, Sardar Patel Maidan, Bakrol-Vadtal Road, Bakrol 388 315, Gujarat, India
| | - R B Subramanian
- P. G. Department of Biosciences, UGC-Centre of Advanced Studies, Satellite Campus, Sardar Patel University, Sardar Patel Maidan, Bakrol-Vadtal Road, Bakrol 388 315, Gujarat, India.
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Evans C, Adetayo T, Wakefield E, Ridley SK, Patel DH, Dimmitt R, Goodin BR, Gowey MA. Assessing the effects of resilience and coping on quality of life in youth with functional abdominal pain disorders. Am J Med Sci 2023. [DOI: 10.1016/s0002-9629(23)00656-0] [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: 01/28/2023]
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Mali H, Shah C, Rudakiya DM, Patel DH, Trivedi U, Subramanian RB. A novel organophosphate hydrolase from Arthrobacter sp. HM01: Characterization and applications. Bioresour Technol 2022; 349:126870. [PMID: 35192947 DOI: 10.1016/j.biortech.2022.126870] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [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: 01/07/2022] [Revised: 02/14/2022] [Accepted: 02/16/2022] [Indexed: 06/14/2023]
Abstract
Bioremediation systems coupled to efficient microbial enzymes have emerged as an attractive approach for the in-situ removal of hazardous organophosphates (OPs) pesticides from the polluted environment. However, the role of engineered enzymes in OPs-degradation is rarely studied. In this study, the potential OPs-hydrolase (opdH) gene (Arthrobacter sp. HM01) was isolated, cloned, expressed, and purified. The recombinant organophosphate hydrolase (ropdH) was ∼29 kDa; which catalyzed a broad-range of OPs-pesticides in organic-solvent (∼99 % in 30 min), and was found to increase the catalytic efficiency by 10-folds over the native enzyme (kcat/Km: 107 M-1s-1). The degraded metabolites were analyzed using HPLC/GCMS. Through site-directed mutagenesis, it was confirmed that, conserved metal-bridged residue (Lys-127), plays a crucial role in OPs-degradation, which shows ∼18-folds decline in OPs-degradation. Furthermore, the catalytic activity and its stability has been enhanced by >2.0-fold through biochemical optimization. Thus, the study suggests that ropdH has all the required properties for OPs bioremediation.
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Affiliation(s)
- Himanshu Mali
- P. G. Department of Biosciences, UGC-Centre of Advanced Studies, Satellite Campus, Sardar Patel University, Sardar Patel Maidan, Bakrol-Vadtal Road, Bakrol, Gujarat 388 315, India
| | - Chandni Shah
- P. G. Department of Biosciences, UGC-Centre of Advanced Studies, Satellite Campus, Sardar Patel University, Sardar Patel Maidan, Bakrol-Vadtal Road, Bakrol, Gujarat 388 315, India
| | - Darshan M Rudakiya
- Synergy Cignpost Diagnostics, 3 Mills Studio, London, E3 3DU, United Kingdom
| | - Darshan H Patel
- Charotar Institute of Paramedical Sciences, Charotar University of Science and Technology, (CHARUSAT), Changa, Gujarat 388421, India
| | - Ujjval Trivedi
- P. G. Department of Biosciences, UGC-Centre of Advanced Studies, Satellite Campus, Sardar Patel University, Sardar Patel Maidan, Bakrol-Vadtal Road, Bakrol, Gujarat 388 315, India
| | - R B Subramanian
- P. G. Department of Biosciences, UGC-Centre of Advanced Studies, Satellite Campus, Sardar Patel University, Sardar Patel Maidan, Bakrol-Vadtal Road, Bakrol, Gujarat 388 315, India.
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Mali H, Shah C, Patel DH, Trivedi U, Subramanian RB. Degradation insight of organophosphate pesticide chlorpyrifos through novel intermediate 2,6-dihydroxypyridine by Arthrobacter sp. HM01. BIORESOUR BIOPROCESS 2022; 9:31. [PMID: 38647761 PMCID: PMC10992969 DOI: 10.1186/s40643-022-00515-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [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: 12/17/2021] [Accepted: 03/07/2022] [Indexed: 02/05/2023] Open
Abstract
Organophosphates (OPs) are hazardous pesticides, but an indispensable part of modern agriculture; collaterally contaminating agricultural soil and surrounding water. They have raised serious food safety and environmental toxicity that adversely affect the terrestrial and aquatic ecosystems and therefore, it become essential to develop a rapid bioremediation technique for restoring the pristine environment. A newly OPs degrading Arthrobacter sp. HM01 was isolated from pesticide-contaminated soil and identified by a ribotyping (16S rRNA) method. Genus Arthrobacter has not been previously reported in chlorpyrifos (CP) degradation, which shows 99% CP (100 mg L-1) degradation within 10 h in mMSM medium and also shows tolerance to a high concentration (1000 mg L-1) of CP. HM01 utilized a broad range of OPs pesticides and other aromatic pollutants including intermediates of CP degradation as sole carbon sources. The maximum CP degradation was obtained at pH 7 and 32 °C. During the degradation, a newly identified intermediate 2,6-dihydroxypyridine was detected through TLC/HPLC/LCMS analysis and a putative pathway was proposed for its degradation. The study also revealed that the organophosphate hydrolase (opdH) gene was responsible for CP degradation, and the opdH-enzyme was located intracellularly. The opdH enzyme was characterized from cell free extract for its optimum pH and temperature requirement, which was 7.0 and 50 °C, respectively. Thus, the results revealed the true potential of HM01 for OPs-bioremediation. Moreover, the strain HM01 showed the fastest rate of CP degradation, among the reported Arthrobacter sp.
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Affiliation(s)
- Himanshu Mali
- P. G. Department of Biosciences, UGC-Centre of Advanced Studies, Satellite Campus, Sardar Patel University, Sardar Patel Maidan, Bakrol-Vadtal Road, Bakrol, 388 315, Gujarat, India
| | - Chandni Shah
- P. G. Department of Biosciences, UGC-Centre of Advanced Studies, Satellite Campus, Sardar Patel University, Sardar Patel Maidan, Bakrol-Vadtal Road, Bakrol, 388 315, Gujarat, India
| | - Darshan H Patel
- Charotar Institute of Paramedical Sciences, Charotar University of Science and Technology (CHARUSAT), Changa, 388421, Gujarat, India
| | - Ujjval Trivedi
- P. G. Department of Biosciences, UGC-Centre of Advanced Studies, Satellite Campus, Sardar Patel University, Sardar Patel Maidan, Bakrol-Vadtal Road, Bakrol, 388 315, Gujarat, India
| | - R B Subramanian
- P. G. Department of Biosciences, UGC-Centre of Advanced Studies, Satellite Campus, Sardar Patel University, Sardar Patel Maidan, Bakrol-Vadtal Road, Bakrol, 388 315, Gujarat, India.
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Mali H, Shah C, Patel DH, Trivedi U, Subramanian RB. Bio-catalytic system of metallohydrolases for remediation of neurotoxin organophosphates and applications with a future vision. J Inorg Biochem 2022; 231:111771. [DOI: 10.1016/j.jinorgbio.2022.111771] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 02/15/2022] [Accepted: 02/19/2022] [Indexed: 12/29/2022]
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Patel DK, Menon DV, Patel DH, Dave G. Linkers: A synergistic way for the synthesis of chimeric proteins. Protein Expr Purif 2021; 191:106012. [PMID: 34767950 DOI: 10.1016/j.pep.2021.106012] [Citation(s) in RCA: 3] [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: 07/30/2021] [Revised: 10/30/2021] [Accepted: 11/03/2021] [Indexed: 11/15/2022]
Abstract
In the cell, the protein domains are attached with the short oligopeptide, commonly known as linker peptide. Besides bridging, the linker assists in the domain-domain interaction and protein folding into the peculiar conformations. Linkers allow or control the movement of protein domains in the dynamic cellular environment. The recent advances in the recombinant DNA technology enable the construction of multiple gene constructs in an open reading frame. The express sequences can work in a cascade to cater for myriad functions. This trend has given momentum to incorporating bridge sequences (linker) that essentially separates the independent domains. According to the cellular need, the bridging partner can be spaced at a secure gap or requires attaching or interacting physically. The flexible or rigid linker can help to achieve such conformations in chimeric fusion proteins. The linker can improve solubility, proteolytic resistance and stability of such fusion proteins. Recently, linker aided protein switches and antibody-drug conjugates are gaining the attention of researchers worldwide. Here, we thoroughly reviewed the types of the linker, strategies for linker engineering and the composition of a linker.
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Affiliation(s)
- Dharti Keyur Patel
- PD Patel Institute of Applied Sciences, CHARUSAT, Changa, 388421, Gujarat, India
| | - Dhanya V Menon
- Tata Institute of Fundamental Research, NCBS, Bangalore, 560065, India
| | - Darshan H Patel
- Charotar Institute of Paramedical Sciences, CHARUSAT, Changa, 388421, Gujarat, India
| | - Gayatri Dave
- PD Patel Institute of Applied Sciences, CHARUSAT, Changa, 388421, Gujarat, India.
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Angira D, Natarajan N, Dedania SR, Patel DH, Thiruvenkatam V. Characterization of P. aeruginosa Glucose 6- Phosphate Isomerase: A Functional Insight via In-Vitro Activity Study. Curr Top Med Chem 2021; 20:2651-2661. [PMID: 32819245 DOI: 10.2174/1568026620666200820153751] [Citation(s) in RCA: 3] [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: 02/23/2020] [Revised: 04/01/2020] [Accepted: 04/04/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Glucose-6-phosphate isomerase (G6PI) catalyses the second step in glycolysis in the reversible interconversion of an aldohexose glucose 6-phosphate, a six membered ring moiety to a ketohexose, fructose 6-phosphate five membered ring moiety. This enzyme is of utmost importance due to its multifunctional role like neuroleukin, autocrine motility factor, etc. in various species. G6PI from Pseudomonas aeruginosa is less explored for its moonlighting properties. These properties can be predicted by studying the active site conservation of residues and their interaction with the specific ligand. METHODS Here, we study the G6PI in a self-inducible construct in bacterial expression system with its purification using Ni-NTA chromatography. The secondary structure of pure G6PI is estimated using circular dichroism to further predict the proper folding form of the protein. The bioactivity of the purified enzyme is quantified using phosphoglucose isomerase colorimetric kit with a value of 12.5 mU/mL. Differential scanning fluorimetry and isothermal titration calorimetry were employed to monitor the interaction of G6PI with its competitive inhibitor, erythrose 4-phosphate and calculated the Tm, Kd and IC50 values. Further, the homology model for the protein was prepared to study the interaction with the erythrose 4-phosphate. MD simulation of the complex was performed at 100 ns to identify the binding interactions. RESULTS We identified hydrogen bonds and water bridges dominating the interactions in the active site holding the protein and ligand with strong affinity. CONCLUSION G6PI was successfully crystallized and data has been collected at 6Å. We are focused on improving the crystal quality for obtaining higher resolution data.
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Affiliation(s)
- Deekshi Angira
- Discipline of Chemistry, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat, India
| | - Nalini Natarajan
- Discipline of Biological Engineering, Indian Institute of Technology Gandhinagar, Gujarat, India
| | - Samir R Dedania
- Department of Biochemistry, P.D. Patel Institute of Applied Sciences, CHARUSAT, Changa Dist. Anand, Gujarat, India
| | - Darshan H Patel
- Department of Biochemistry, P.D. Patel Institute of Applied Sciences, CHARUSAT, Changa Dist. Anand, Gujarat, India
| | - Vijay Thiruvenkatam
- Discipline of Biological Engineering, Indian Institute of Technology Gandhinagar, Gujarat, India
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Dedania SR, Patel VK, Soni SS, Patel DH. Immobilization of Agrobacterium tumefaciens d-psicose 3-epimerase onto titanium dioxide for bioconversion of rare sugar. Enzyme Microb Technol 2020; 140:109605. [DOI: 10.1016/j.enzmictec.2020.109605] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 05/18/2020] [Accepted: 05/22/2020] [Indexed: 10/24/2022]
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Prajapati AS, Pawar VA, Panchal KJ, Sudhir AP, Dave BR, Patel DH, Subramanian RB. Effects of substrate binding site residue substitutions of xynA from Bacillus amyloliquefaciens on substrate specificity. BMC Biotechnol 2018; 18:9. [PMID: 29439688 PMCID: PMC5812043 DOI: 10.1186/s12896-018-0420-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 01/30/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The aromatic residues of xylanase enzyme, W187, Y124, W144, Y128 and W63 of substrate binding pocket from Bacillus amyloliquefaciens were investigated for their role in substrate binding by homology modelling and sequence analysis. These residues are highly conserved and play an important role in substrate binding through steric hindrance. The substitution of these residues with alanine allows the enzyme to accommodate nonspecific substrates. RESULTS Wild type and mutated genes were cloned and overexpressed in BL21. Optimum pH and temperature of rBAxn exhibited pH 9.0 and 50 °C respectively and it was stable up to 215 h. Along with the physical properties of rBAxn, kinetic parameters (Km 19.34 ± 0.72 mg/ml; kcat 6449.12 ± 155.37 min- 1 and kcat/Km 333.83 ± 6.78 ml min- 1 mg- 1) were also compared with engineered enzymes. Out of five mutations, W63A, Y128A and W144A lost almost 90% activity and Y124A and W187A retained almost 40-45% xylanase activity. CONCLUSIONS The site-specific single mutation, led to alteration in substrate specificity from xylan to CMC while in case of double mutant the substrate specificity was altered from xylan to CMC, FP and avicel, indicating the role of aromatic residues on substrate binding, catalytic process and overall catalytic efficiency.
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Affiliation(s)
- Anil S. Prajapati
- P. G. Department of Biosciences, UGC-Centre of advanced studies, Satellite campus, Sardar Patel University, Sardar Patel Maidan, Bakrol-Vadtal Road, PO Box 39, Vallabh Vidyanagar, Gujarat 388 120 India
| | - Vishakha A. Pawar
- P. G. Department of Biosciences, UGC-Centre of advanced studies, Satellite campus, Sardar Patel University, Sardar Patel Maidan, Bakrol-Vadtal Road, PO Box 39, Vallabh Vidyanagar, Gujarat 388 120 India
| | - Ketankumar J. Panchal
- P. G. Department of Biosciences, UGC-Centre of advanced studies, Satellite campus, Sardar Patel University, Sardar Patel Maidan, Bakrol-Vadtal Road, PO Box 39, Vallabh Vidyanagar, Gujarat 388 120 India
| | - Ankit P. Sudhir
- P. G. Department of Biosciences, UGC-Centre of advanced studies, Satellite campus, Sardar Patel University, Sardar Patel Maidan, Bakrol-Vadtal Road, PO Box 39, Vallabh Vidyanagar, Gujarat 388 120 India
| | - Bhaumik R. Dave
- P. G. Department of Biosciences, UGC-Centre of advanced studies, Satellite campus, Sardar Patel University, Sardar Patel Maidan, Bakrol-Vadtal Road, PO Box 39, Vallabh Vidyanagar, Gujarat 388 120 India
| | - Darshan H. Patel
- P. D. Patel Institute of Applied Sciences, Charotar University of Science and Technology (CHARUSAT), Changa, Anand, Gujarat India
| | - R. B. Subramanian
- P. G. Department of Biosciences, UGC-Centre of advanced studies, Satellite campus, Sardar Patel University, Sardar Patel Maidan, Bakrol-Vadtal Road, PO Box 39, Vallabh Vidyanagar, Gujarat 388 120 India
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Pawar VA, Prajapati AS, Akhani RC, Patel DH, Subramanian RB. Molecular and biochemical characterization of a thermostable keratinase from Bacillus altitudinis RBDV1. 3 Biotech 2018; 8:107. [PMID: 29430368 DOI: 10.1007/s13205-018-1130-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [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: 08/04/2017] [Accepted: 01/20/2018] [Indexed: 11/26/2022] Open
Abstract
A thermostable keratinase designated as KBALT was purified from Bacillus altitudinis RBDV1 from a poultry farm in Gujarat, India. The molecular weight of the native KBALT (nKBALT) purified using ammonium sulfate and ion exchange and gel permeation chromatography with a 40% yield and 80-fold purification was estimated to be ~ 43 kDa. The gene for KBALT was successfully cloned, sequenced and expressed in Escherichia coli. Recombinant KBALT (rKBALT) when purified using a single step Ni-NTA His affinity chromatography achieved a yield of 38.20% and a 76.4-fold purification. Comparison of the deduced amino acid sequence of rKBALT with known proteases of Bacillus species and inhibitory effect of PMSF suggest that rKBALT was a subtilisin-like serine protease. Both native and rKBALT exhibited higher activity at 85 °C and pH 8.0 in the presence of Mg2+, Mn2+, Zn2+, Ba2+ and Fe3+ metal ions. Interestingly, 70% of their activity was retained at temperatures ranging from 35 to > 95 °C. The keratinolytic activity of both nKBALT and rKBALT was enhanced in the presence of reducing agents. They exhibited broad substrate specificity towards various protein substrates. KBALT was determined for its kinetic properties by calculating its Km (0.61 mg/ml) and Vmax (1673 U/mg/min) values. These results suggest KBALT as a robust and promising contender for enzymatic processing of keratinous wastes in waste processing plants.
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Affiliation(s)
- Vishakha A Pawar
- 1P. G. Department Of Biosciences, Satellite Campus, Sardar Patel Maidaan, Bakrol-Vadtal Road, Sardar Patel University, P.O. Box No. 39, Vallabh Vidyanagar, Gujarat 388120 India
| | - Anil S Prajapati
- 1P. G. Department Of Biosciences, Satellite Campus, Sardar Patel Maidaan, Bakrol-Vadtal Road, Sardar Patel University, P.O. Box No. 39, Vallabh Vidyanagar, Gujarat 388120 India
| | - Rekha C Akhani
- 2Department of Biochemistry, P. D. Patel Institute of Applied Sciences, Charotar University of Science and Technology, Changa, Anand, Gujarat India
| | - Darshan H Patel
- 2Department of Biochemistry, P. D. Patel Institute of Applied Sciences, Charotar University of Science and Technology, Changa, Anand, Gujarat India
| | - R B Subramanian
- 1P. G. Department Of Biosciences, Satellite Campus, Sardar Patel Maidaan, Bakrol-Vadtal Road, Sardar Patel University, P.O. Box No. 39, Vallabh Vidyanagar, Gujarat 388120 India
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Prajapati AS, Panchal KJ, Pawar VA, Noronha MJ, Patel DH, Subramanian RB. Review on Cellulase and Xylanase Engineering for Biofuel Production. Ind Biotechnol (New Rochelle N Y) 2018. [DOI: 10.1089/ind.2017.0027] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- Anil S. Prajapati
- P.G. Department of Biosciences, UGC-Centre of Advanced Studies, Satellite campus, Sardar Patel Maidan, Sardar Patel University, Gujarat, India
| | - Ketankumar J. Panchal
- P.G. Department of Biosciences, UGC-Centre of Advanced Studies, Satellite campus, Sardar Patel Maidan, Sardar Patel University, Gujarat, India
| | - Vishakha A. Pawar
- P.G. Department of Biosciences, UGC-Centre of Advanced Studies, Satellite campus, Sardar Patel Maidan, Sardar Patel University, Gujarat, India
| | - Monica J. Noronha
- P.G. Department of Biosciences, UGC-Centre of Advanced Studies, Satellite campus, Sardar Patel Maidan, Sardar Patel University, Gujarat, India
| | - Darshan H. Patel
- P. D. Patel Institute of Applied Sciences, Charotar University of Science and Technology Gujarat, India
| | - R. B. Subramanian
- P.G. Department of Biosciences, UGC-Centre of Advanced Studies, Satellite campus, Sardar Patel Maidan, Sardar Patel University, Gujarat, India
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Patel JS, Patel DH, Desai R, Shah S, Chudasama P, Joshi S, Patel B. Application of an industrial waste magnetic iron dust as a solid phase support for immobilizing enzyme of industrial applications. ADSORPT SCI TECHNOL 2016. [DOI: 10.1177/0263617416661563] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- Jagdish Shantilal Patel
- P.D. Patel Institute of Applied Science, Charotar University of Science and Technology (CHARUSAT), India
| | - Darshan H Patel
- P.D. Patel Institute of Applied Science, Charotar University of Science and Technology (CHARUSAT), India
| | - Rucha Desai
- P.D. Patel Institute of Applied Science, Charotar University of Science and Technology (CHARUSAT), India
| | - Sunil Shah
- Shah-Schulman Center for Surface Science & Nanotechnology, Dharmsinh Desai University, India
| | - Piyush Chudasama
- P.D. Patel Institute of Applied Science, Charotar University of Science and Technology (CHARUSAT), India
| | - Sachin Joshi
- Dr. K. C. Patel R & D Centre, Charotar University of Science and Technology (CHARUSAT), India
| | - Bhargav Patel
- Shah-Schulman Center for Surface Science & Nanotechnology, Dharmsinh Desai University, India
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Sudhir AP, Agarwaal VV, Dave BR, Patel DH, Subramanian R. Enhanced catalysis of l-asparaginase from Bacillus licheniformis by a rational redesign. Enzyme Microb Technol 2016; 86:1-6. [DOI: 10.1016/j.enzmictec.2015.11.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 11/20/2015] [Accepted: 11/23/2015] [Indexed: 10/22/2022]
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15
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Kim YO, Lee YG, Patel DH, Kim HM, Ahn SJ, Bae HJ. Zn tolerance of novel Colocasia esculenta metallothionein and its domains in Escherichia coli and tobacco. J Plant Res 2012; 125:793-804. [PMID: 22610130 DOI: 10.1007/s10265-012-0492-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Accepted: 04/07/2012] [Indexed: 06/01/2023]
Abstract
Contrary to extensive researches on the roles of metallothioneins (MTs) in metal tolerance of animals, the roles of plant MTs in metal tolerance are largely under investigation. In this study, we evaluated the functional role of type 2 MT from Colocasia esculenta (CeMT2b) in Zn tolerance of tobacco and E. coli cells. Under Zn-stress conditions, transgenic tobacco overexpressing CeMT2b displayed much better seedling growth, a significant decrease in the levels of H(2)O(2) and an increase in Zn accumulation compared with the wild type. Overexpression of CeMT2b in E. coli greatly enhanced Zn tolerance and Zn accumulation under Zn stresses compared with control cells. CeMT2b bound 5.38 ± 0.29 atoms of Zn per protein. To identify a structural domain of CeMT2b for Zn binding, we investigated the growth of E. coli expressing each of the N-terminal, C-terminal, and central linker domains or a CNC motif deletion from the C-terminus of full-length CeMT2b. The results showed that the CNC motif is required for Zn tolerance, and the N-terminal domain is more effective in Zn tolerance than the C-terminal domain. Taken together, our results provide direct evidence for functional contributions of CeMT2b in Zn tolerance of tobacco and E. coli cells.
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Affiliation(s)
- Yeon-Ok Kim
- Bio-Energy Research Institute, Chonnam National University, 300 Youngbong-Dong, Buk-Gu, Gwangju, 500-757, Republic of Korea
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16
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Kim HM, Lee YG, Patel DH, Lee KH, Lee DS, Bae HJ. Characteristics of bifunctional acidic endoglucanase (Cel5B) from Gloeophyllum trabeum. J Ind Microbiol Biotechnol 2012; 39:1081-9. [PMID: 22395898 DOI: 10.1007/s10295-012-1110-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Accepted: 02/15/2012] [Indexed: 11/27/2022]
Abstract
The endoglucanase (Cel5B) from the filamentous fungus Gloeophyllum trabeum was cloned and expressed without a signal peptide, and alanine residue 22 converted to glutamine in Pichia pastoris GS115. The DNA sequence of Cel5B had an open reading frame of 1,077 bp, encoding a protein of 359 amino acid residues with a molecular weight of 47 kDa. On the basis of sequence similarity, Cel5B displayed active site residues at Glu-175 and Glu-287. Both residues lost full hydrolytic activity when replaced with alanine through point mutation. The purified recombinant Cel5B showed very high specific activity, about 80- to 1,000-fold and 13- to 70-fold in comparison with other endoglucanases and cellobiohydrolase, on carboxymethylcellulose and filter paper, respectively, at pH 3.5 and 55°C. Cel5B displayed bifunctional characteristics under acidic conditions. The kinetic properties of the enzyme determined using a Lineweaver-Burk plot indicated that Cel5B is a catalytically efficient cellulolytic enzyme. These results suggest that Cel5B has high bifunctional endo- and exoglucanase activity under acidic conditions and is a good candidate for bioconversion of lignocellulose.
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Affiliation(s)
- Ho Myeong Kim
- Department of Forest Products and Technology, Chonnam National University, Gwangju, 500-757, Republic of Korea
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17
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Kim YO, Patel DH, Lee DS, Song Y, Bae HJ. High cadmium-binding ability of a novel Colocasia esculenta metallothionein increases cadmium tolerance in Escherichia coli and tobacco. Biosci Biotechnol Biochem 2011; 75:1912-20. [PMID: 21979068 DOI: 10.1271/bbb.110289] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Experimental evidence in vivo as to the functional roles and binding properties to cadmium (Cd) of type-2 plants metallothionein (MT) has been limited thus far. We investigated the biological role of metallothionein from Colocasia esculenta (CeMT2b) in Escherichia coli and tobacco, and developed a new model for the relationship between Cd tolerance and Cd-binding ability. Heterologous expression of CeMT2b in Escherichia coli greatly enhanced Cd tolerance and accumulated Cd content as compared to control cells. The molecular weight of CeMT2b increased with Cd, and CeMT2b bound up to 5.96±1 molar ratio (Cd/protein). Under Cd stress, transgenic tobacco plants displayed much better seedling growth and high Cd accumulation than the wild type. The presence of an extra CXC motif in CeMT2b contributed to the enhanced Cd-tolerance. The present study provides the first insight into the ability of type-2 plant MT to bind physiological Cd.
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Affiliation(s)
- Yeon-Ok Kim
- Bio-Energy Research Institute, Chonnam National University, Gwangju, Korea
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18
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Oza VP, Parmar PP, Patel DH, Subramanian RB. Cloning, expression and characterization of l-asparaginase from Withania somnifera L. for large scale production. 3 Biotech 2011; 1:21-26. [PMID: 22558532 PMCID: PMC3339582 DOI: 10.1007/s13205-011-0003-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Accepted: 02/16/2011] [Indexed: 11/30/2022] Open
Abstract
l-Asparaginase (E.C. 3.5.1.1) is used as a therapeutic agent in the treatment of acute childhood lymphoblastic leukemia. It is found in a variety of organisms such as microbes, plants and mammals. In plants, l-asparaginase enzymes are required to catalyze the release of ammonia from asparagine, which is the main nitrogen-relocation molecule in these organisms. An Indian medicinal plant, Withania somnifera was reported as a novel source of l-asparaginase. l-Asparaginase from W. somnifera was cloned and overexpressed in E. coli. The enzymatic properties of the recombinant enzyme were investigated and the kinetic parameters (K(m), k(cat)) for a number of substrates were determined. The kinetic parameters of selected substrates were determined at various pH and the pH- and temperature-dependence profiles were analyzed. WA gene successfully cloned into E. coli BL21 (DE3) showed high asparaginase activity with a specific activity of 17.3 IU/mg protein.
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Affiliation(s)
- Vishal P. Oza
- Department of Plant Biotechnology, B R D School of Biosciences, Sardar Patel Maidan, Vadtal Road, Satellite Campus, Sardar Patel University, Post Box No. 39, Vallabh Vidyanagar, 388 120 Gujarat India
| | - Pritesh P. Parmar
- Department of Plant Biotechnology, B R D School of Biosciences, Sardar Patel Maidan, Vadtal Road, Satellite Campus, Sardar Patel University, Post Box No. 39, Vallabh Vidyanagar, 388 120 Gujarat India
| | - Darshan H. Patel
- Department of Plant Biotechnology, B R D School of Biosciences, Sardar Patel Maidan, Vadtal Road, Satellite Campus, Sardar Patel University, Post Box No. 39, Vallabh Vidyanagar, 388 120 Gujarat India
| | - R. B. Subramanian
- Department of Plant Biotechnology, B R D School of Biosciences, Sardar Patel Maidan, Vadtal Road, Satellite Campus, Sardar Patel University, Post Box No. 39, Vallabh Vidyanagar, 388 120 Gujarat India
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19
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Patel DH, Wi SG, Lee SG, Lee DS, Song YH, Bae HJ. Substrate specificity of the Bacillus licheniformis lyxose isomerase YdaE and its application in in vitro catalysis for bioproduction of lyxose and glucose by two-step isomerization. Appl Environ Microbiol 2011; 77:3343-50. [PMID: 21421786 PMCID: PMC3126444 DOI: 10.1128/aem.02693-10] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Accepted: 03/10/2011] [Indexed: 12/25/2022] Open
Abstract
Enzymatic processes are useful for industrially important sugar production, and in vitro two-step isomerization has proven to be an efficient process in utilizing readily available sugar sources. A hypothetical uncharacterized protein encoded by ydaE of Bacillus licheniformis was found to have broad substrate specificities and has shown high catalytic efficiency on D-lyxose, suggesting that the enzyme is D-lyxose isomerase. Escherichia coli BL21 expressing the recombinant protein, of 19.5 kDa, showed higher activity at 40 to 45°C and pH 7.5 to 8.0 in the presence of 1.0 mM Mn²+. The apparent K(m) values for D-lyxose and D-mannose were 30.4 ± 0.7 mM and 26 ± 0.8 mM, respectively. The catalytic efficiency (k(cat)/K(m)) for lyxose (3.2 ± 0.1 mM⁻¹ s⁻¹) was higher than that for D-mannose (1.6 mM⁻¹ s⁻¹). The purified protein was applied to the bioproduction of D-lyxose and D-glucose from d-xylose and D-mannose, respectively, along with the thermostable xylose isomerase of Thermus thermophilus HB08. From an initial concentration of 10 mM D-lyxose and D-mannose, 3.7 mM and 3.8 mM D-lyxose and D-glucose, respectively, were produced by two-step isomerization. This two-step isomerization is an easy method for in vitro catalysis and can be applied to industrial production.
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Affiliation(s)
- Darshan H. Patel
- Bio-energy Research Institute, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - Seung Gon Wi
- Bio-energy Research Institute, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - Seong-Gene Lee
- Department of Biotechnology, Bio-energy Research Center, Biotechnology Research Institute, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - Dae-Seok Lee
- Bio-energy Research Institute, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - Youn-ho Song
- Department of Biotechnology, Bio-energy Research Center, Biotechnology Research Institute, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - Hyeun-Jong Bae
- Bio-energy Research Institute, Chonnam National University, Gwangju 500-757, Republic of Korea
- Department of Forest Products and Technology (BK21 Program), Chonnam National University, Gwangju 500-757, Republic of Korea
- Department of Bioenergy Science and Technology, Chonnam National University, Gwangju 500-757, Republic of Korea
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Son KK, Tkach D, Patel DH. Zeta potential of transfection complexes formed in serum-free medium can predict in vitro gene transfer efficiency of transfection reagent. Biochim Biophys Acta 2000; 1468:11-4. [PMID: 11018646 DOI: 10.1016/s0005-2736(00)00312-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We have tested the zeta potential (zeta, the surface charge density) of transfection complexes formed in serum-free medium as a rapid and reliable technique for screening transfection efficiency of a new reagent or formulation. The complexes of CAT plasmid DNA (1 microgram) and DC-chol/DOPE liposomes (3-20 nmol) were largely negatively charged (zeta=-15 to -21 mV), which became neutral or positive as 0.5 microgram or a higher amount of poly-L-lysine (PLL, MW 29300 or MW 204000) was added (-3.16+/-3.47 to +6.04+/-2.23 mV). However, the complexes of CAT plasmid DNA (1 microgram) and PLL MW 29300 (0.5 microgram or higher) were neutral or positively charged (-3.22+/-2.3 to +6.55+/-0.64 mV), which remained the same as 6.6 nmol of the liposomes was added. The complexes formed between two positively charged compounds, PLL MW 29300 (0.5 microgram) and the liposomes (3-20 nmol), were as closely positively charged as DNA/PLL or DNA/liposomes/PLL complexes (+3.31+/-0.41 to 7.16+/-1.0 mV). These results indicate that PLL determined the overall charge of the DNA/liposome/PLL ternary complexes. The complexes formed with histone (0.75 microgram or higher) were also positively charged, whose transfection activity was as high as PLL MW 29300. However, the complexes formed with protamine or PLL MW 2400 remained negatively charged. These observations are in good agreement with the transfection activity of the formulation containing each polycationic polymer. The presence of PLL MW 29300 did not change the hydrodynamic diameter of DNA/liposome/PLL complexes (d(H)=275-312 nm). The complexes made of different sizes of PLL (MW 2400 and 204000) also did not significantly change their size. This suggests that DNA condensation may not be critical. Therefore, zeta of the transfection complex can predict the transfection efficiency of a new formulation or reagent.
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Affiliation(s)
- K K Son
- Department of Pharmaceutics, Rutgers, The State University of New Jersey, College of Pharmacy, 160 Frelinghuysen Rd., 08854, Piscataway, NJ, USA
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21
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Son KK, Patel DH, Tkach D, Park A. Cationic liposome and plasmid DNA complexes formed in serum-free medium under optimum transfection condition are negatively charged. Biochim Biophys Acta 2000; 1466:11-5. [PMID: 10825426 DOI: 10.1016/s0005-2736(00)00176-0] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
In medium where in vitro transfection is routinely performed, DC-chol liposomes alone were nearly neutral, whereas the DC-chol liposome/DNA complexes were largely negatively charged which changed only slightly at all [liposome]/[DNA] ratios (zeta=-27.1 to -21.8 mV). Three other commercial transfection reagents, Lipofectin(R), LipofectAMINE 2000, and SuperFect, were also largely negatively charged when complexed with DNA. The aggregation of liposomes in medium was prevented by the addition of DNA. Incubation of the complexes in medium did not change their size, charge or lipofection activity for 30 min. These results suggest that, in medium, the liposome/DNA complexes were formed at the time of mixing with negative charges.
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Affiliation(s)
- K K Son
- Department of Pharmaceutics, Rutgers, The State University of New Jersey, College of Pharmacy, 160 Frelinghuysen Rd., Piscataway, NJ 08854, USA.
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Patel DH, Allay JA, Belt JA, Sorrentino BP. Retroviral transfer of the hENT2 nucleoside transporter cDNA confers broad-spectrum antifolate resistance in murine bone marrow cells. Blood 2000; 95:2356-63. [PMID: 10733507] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023] Open
Abstract
Antifolate drugs such as methotrexate are commonly used in cancer chemotherapy. It may be possible to increase the antitumor activity of antifolates by the coadministration of drugs that inhibit nucleoside transport, thereby blocking the capacity of tumor cells to salvage nucleotide precursors. An important limitation of this approach is severe myelosuppression caused by many of these drug combinations. For this reason, we have developed a gene therapy strategy to protect bone marrow cells against combined treatment with antifolates and nitrobenzylmercaptopurine riboside (NBMPR), a potent inhibitor of the es nucleoside transporter. A retroviral vector (MeiIRG) was constructed that expressed the NBMPR-insensitive ei transporter, hypothesizing that transduced bone marrow cells would survive drug treatment because of the preservation of nucleoside salvage pathways. In vitro clonogenic assays confirmed that the MeiIRG vector did protect myeloid progenitors against the toxic effects of 3 different antifolates when each was combined with NBMPR. On testing this system in vivo, decreased myelosuppression was observed in mice transplanted with MeiIRG-transduced bone marrow cells and subsequently treated with trimetrexate and NBMPR-P. In these mice, significant increases were noted in absolute neutrophil count nadirs, reticulocyte indices, and the numbers of myeloid progenitors in the bone marrow. Furthermore, a survival advantage was associated with transfer of the MeiIRG vector, indicating that significant dose intensification was possible with this approach. In summary, the MeiIRG vector can decrease the toxicity associated with the combined use of antifolates and NBMPR-P and thereby may provide a strategy for simultaneously sensitizing tumor cells while protecting hematopoietic cells.
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Affiliation(s)
- D H Patel
- Division of Experimental Hematology, Department of Molecular Pharmacology, St. Jude Children's Research Hospital, Memphis, TN, USA.
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Patel DH, Crawford CR, Naeve CW, Belt JA. Cloning, genomic organization and chromosomal localization of the gene encoding the murine sodium-dependent, purine-selective, concentrative nucleoside transporter (CNT2). Gene 2000; 242:51-8. [PMID: 10721696 DOI: 10.1016/s0378-1119(99)00521-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A PCR-based strategy was used to isolate a 2653 bp cDNA encoding the mouse sodium-dependent, purine nucleoside selective, concentrative nucleoside transporter (designated mCNT2). The deduced protein sequence exhibits 93 and 80% identity to the previously cloned rat and human sodium-dependent, purine nucleoside selective, nucleoside transporters, respectively. Characterization of 3H-nucleoside uptake by COS-1 cells transiently transfected with the cDNA demonstrated that it encoded a functional nucleoside transport activity with selectivity for purine nucleosides. The cDNA was used to screen a murine (strain 129SvJ/6) genomic library in pBeloBAC11 to identify a clone containing the mCNT2 gene. A PCR strategy was used to identify and sequence the intron-exon boundaries and to determine the approximate sizes of the introns. The mCNT2 gene spans approximately 13.7 kb and is encoded by 15 exons. The gene was mapped to mouse chromosome 2e3 by fluorescence in situ hybridization.
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Affiliation(s)
- D H Patel
- Department of Molecular Pharmacology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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Crawford CR, Patel DH, Naeve C, Belt JA. Cloning of the human equilibrative, nitrobenzylmercaptopurine riboside (NBMPR)-insensitive nucleoside transporter ei by functional expression in a transport-deficient cell line. J Biol Chem 1998; 273:5288-93. [PMID: 9478986 DOI: 10.1074/jbc.273.9.5288] [Citation(s) in RCA: 169] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mammalian cells obtain nucleic acid precursors through the de novo synthesis of nucleotides and the salvage of exogenous nucleobases and nucleosides. The first step in the salvage pathway is transport across the plasma membrane. Several transport activities, including equilibrative and concentrative mechanisms, have been identified by their functional properties. We report here the functional cloning of a 2.6-kilobase pair human cDNA encoding the nitrobenzylmercaptopurine riboside (NBMPR)-insensitive, equilibrative nucleoside transporter ei by functional complementation of the transport deficiency in a subline of CEM human leukemia cells. Expression of this cDNA conferred an NBMPR-insensitive, sodium-independent nucleoside transport activity to the cells that exhibited substrate specificity and inhibitor sensitivity characteristic of the ei transporter. The cDNA contained a single open reading frame that encoded a 456-residue protein with 11 potential membrane-spanning regions and two consensus sites for N-glycosylation in the first predicted extracellular loop. The predicted protein was 50% identical to the recently cloned human NBMPR-sensitive, equilibrative nucleoside transporter ENT1 and thus was designated ENT2. Surprisingly, the carboxyl-terminal portion of the ENT2 protein was nearly identical to a smaller protein in the GenBankTM data base (human HNP36, 326 residues) that has been identified as a growth factor-induced delayed early response gene of unknown function. Comparison of the ENT2 and HNP36 nucleotide sequences suggested that HNP36 was translated from a second start codon within the ENT2 open reading frame. Transient expression studies with the full-length ENT2 and a 5'-truncated construct that lacks the first start codon (predicted protein 99% identical to HNP36) demonstrated that only the full-length construct conferred uridine transport activity to the cells. These data suggest that the delayed early response gene HNP36 is a truncated form of ENT2 and that the full-length open reading frame of ENT2 is required for production of a functional plasma membrane ei transporter.
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Affiliation(s)
- C R Crawford
- Department of Molecular Pharmacology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
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