1
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Asha S, Bessy TC, Joe Sherin JF, Vani CV, Kumar CV, Bindhu MR, Sureshkumar S, Al-Khattaf FS, Hatamleh AA. Efficient photocatalytic degradation of industrial contaminants by Piper longum mediated ZnO nanoparticles. Environ Res 2022; 208:112686. [PMID: 35032540 DOI: 10.1016/j.envres.2022.112686] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [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: 09/28/2021] [Revised: 11/04/2021] [Accepted: 12/25/2021] [Indexed: 06/14/2023]
Abstract
Piper longum extract as a reducing agent in green synthesis method is used to synthesize ZnO nanoparticles (ZnO-NPs). The impact of the reductant on the structural, optical and surface morphological properties of ZnO-NPs can be analyzed. Piper longum extract has delicately tuned the band gap of ZnO-NPs. Increase in energy band gap indicates an increase in the number of capping molecules in the prepared ZnO nanoparticles. The carbohydrates and proteins not only play a fundamental role in ZnO capping, which is important for its stability, determination and biocompatibility. Thus obtained nanosized ZnO particles are confirmed by the surface morphological studies. Because of various surface interface properties might have different physical-chemical, desorption-adsorption abilities in the direction towards microbes, create different antibacterial performances. S.aureus has maximum inhibition zone of 23 mm and Escherichia coli has minimum inhibition zone of 7 mm. To assess the photocatalytic activity of the prepared ZnO-NPs under UV light irradiation, methyl orange, malachite green and methylene blue dyes were utilized as model contaminants. The degradation efficiency of MG, MB and MO dyes solution is found that 96%, 69% and 48% of degradation efficiency respectively under ultraviolet light irradiation. The properties of synthetic nanopowders suggest that they have important potential for a variety of biochemical and environmental applications.
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Affiliation(s)
- S Asha
- Department of Physics, St. Jude's College, Thoothoor, Affiliated to Manonmaniam Sundaranar University, Abishekapatti, Tirunelveli, Tamilnadu, India
| | - T C Bessy
- Department of Physics, Annai Velankanni College, Tholayavattam, 629167, Tamilnadu, India
| | - J F Joe Sherin
- Department of Physics, St. Jude's College, Thoothoor, Affiliated to Manonmaniam Sundaranar University, Abishekapatti, Tirunelveli, Tamilnadu, India
| | - C Vijil Vani
- Department of Physics, Government Polytechnic College, Thoothukudi, 628003, Tamilnadu, India
| | - C Vijaya Kumar
- Department of Physics, St. Jude's College, Thoothoor, Affiliated to Manonmaniam Sundaranar University, Abishekapatti, Tirunelveli, Tamilnadu, India.
| | - M R Bindhu
- Department of Physics, Sree Devi Kumari Women's College, Kuzhithurai, 629163, Tamilnadu, India.
| | - Shanmugam Sureshkumar
- Department of Animal Resource & Science, Dankook University, Cheonan-si, Chungnam, South Korea
| | - Fatimah S Al-Khattaf
- Department of Botany and Microbiology, College of Science, King Saud University, P.O. Box 2455, Riyadh, 11451, Saudi Arabia
| | - Ashraf Atef Hatamleh
- Department of Botany and Microbiology, College of Science, King Saud University, P.O. Box 2455, Riyadh, 11451, Saudi Arabia
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2
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Joe Sherin JF, Bessy TC, Asha S, Kumar CV, Huessien D, Bindhu MR, Rasheed RA, Alarjani KM. Microwave assisted hydrothermally synthesized cobalt doped zinc ferrites nanoparticles for the degradation of organic dyes and antimicrobial applications. Environ Res 2022; 208:112687. [PMID: 34999033 DOI: 10.1016/j.envres.2022.112687] [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: 09/30/2021] [Revised: 12/06/2021] [Accepted: 12/25/2021] [Indexed: 06/14/2023]
Abstract
A novel photocatalyst based cobalt doped zinc ferrites nanoparticles (Co-ZnFe2O4 NPs) was prepared to actively concentrate degradation of organic dyes in water. The aim this study is to investigate the effect of substitution of Co2+ for Zn2+ in zinc ferrites nanoparticles and is characterized with UV-visible spectroscopy, XRD, TEM, SEM, Photoluminescence and Vibrating sample magnetometer technique. When the calcinations temperature increases from 150 °C to 450 °C the amorphous ferrites begins to vanish and the characteristic reflections of cubic spinal Co-ZnFe2O4 phase are only observed at 450 °C. The band gap energy (Eg) of sample calcined at 250 °C is calculated at 5.2 eV and that of 450 °C is 4.5 eV. The observed value of band gap energy decreased with increasing calcinations temperature in the samples. The increase in PL peak intensity is due to collective emissions and light-scattering. The doping material, cobalt substitution at spinel zinc ferrites surface, and hence gradually decrease the amorphous effect, increase the saturation magnetization and decrease the coercivity while increasing the temperature. The compounds calcined at 250 °C and 450 °C were investigated for their in vitro antimicrobial activity against Staphylococcus aureus. A sample with 450 °C calcination temperature leads to higher efficiencies in the inhibition of growth of bacteria and degradation of organic dyes. Hence, this study provides a novel photocatalyst of Co-ZnFe2O4 NPs in the tile to degrade and analyze the environmentally ignored organic compounds.
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Affiliation(s)
- J F Joe Sherin
- Department of Physics, St. Jude's College, Thoothoor, Affiliated to Manonmaniam Sundaranar University, Abishekapatti Tirunelveli, Tamilnadu, India
| | - T C Bessy
- Department of Physics, Annai Velankanni College, Tholayavattam, 629167, Tamilnadu, India
| | - S Asha
- Department of Physics, St. Jude's College, Thoothoor, Affiliated to Manonmaniam Sundaranar University, Abishekapatti Tirunelveli, Tamilnadu, India
| | - C Vijaya Kumar
- Department of Physics, St. Jude's College, Thoothoor, Affiliated to Manonmaniam Sundaranar University, Abishekapatti Tirunelveli, Tamilnadu, India.
| | - Dina Huessien
- Department of Chemistry, College of Sciences and Health, Cleveland State University, 2501 Euclid Ave, Cleveland, OH, 44115, United States
| | - M R Bindhu
- Department of Physics, Sree Devi Kumari Women's College, Kuzhithurai, 629163, Tamilnadu, India.
| | - Rabab Ahmed Rasheed
- Histology & Cell Biology Department, Faculty of Medicine, King Salman International University, South Sinai, Egypt
| | - Khaloud Mohammed Alarjani
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia
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3
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Abstract
A high yielding method for the aqueous exfoliation of graphite crystals to produce high quality graphene nanosheets in a kitchen blender is described here. Bovine serum albumin (BSA), β-lactoglobulin, ovalbumin, lysozyme, and hemoglobin as well as calf serum were used for the exfoliation of graphene. Among these, BSA gave the maximum exfoliation efficiency, exceeding 4mgmL(-1)h(-1) of graphene. Quality of graphene produced was examined by Raman spectroscopy, which indicated 3-5 layer graphene of very high quality and very low levels of defects. Transmission electron microscopy indicated an average size of ~0.5μm flakes. The graphene/BSA dispersions were stable over pH 3.0-11, and at 5°C or 50°C, for more than 2 months. Current approach gave higher rates of BSA/graphene (BioGraphene) in better yields than other methods. Calf serum, when used in place of BSA, also gave high yields of good quality BioGraphene and these preparations may be of direct use for cell culture studies. A simple example of BioGraphene preparation is described that can be adapted in most laboratories, and graphene-adsorbed glucose oxidase is nearly as active as the free enzyme. Current approach may facilitate large-scale production of graphene in most laboratories around the world and it may open new opportunities for biological applications of graphene.
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Affiliation(s)
- C V Kumar
- Department of Chemistry, University of Connecticut, Storrs, Connecticut, USA; Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, USA; Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bengaluru, Karnataka, India; Institute of Material Science, University of Connecticut, Storrs, Connecticut, USA.
| | - A Pattammattel
- Department of Chemistry, University of Connecticut, Storrs, Connecticut, USA
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4
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Kumar CV, Satyanarayana S, Rao BR, Palur RS. Extreme lateral approach to ventral and ventrolaterally situated lesions of the lower brainstem and upper cervical cord. Skull Base 2011; 11:265-75. [PMID: 17167629 PMCID: PMC1656882 DOI: 10.1055/s-2001-18633] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Lesions situated ventrally and ventrolaterally to the lower brainstem and upper cervical spinal cord test the skills of neurosurgeons. We present our experience with eight such patients who underwent the extreme lateral craniocervical approach. The pathologies encountered include three distal vertebral aneurysms, one prepontine epidermoid, one anterior foramen magnum meningioma, and three high cervical dumbbell neurofibromas. All lesions were treated effectively. Postoperatively, the patients improved significantly. Complications included transient lower cranial nerve paresis in three patients, meningitis in one patient, and a pseudomeningocele in two patients. All complications improved with therapy. We conclude that the extreme lateral approach offers excellent visualization and access with minimal neural retraction for treating these difficult lesions.
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5
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Abstract
The ability of the jack bean lectin concanavalin A (ConA) to bind seven membered ring (septanose) monosaccharides has been investigated by isothermal titration calorimetry (ITC) and saturation transfer difference (STD) NMR spectroscopy.
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Affiliation(s)
- Steve Castro
- Department of Chemistry, University of Connecticut, 55 North Eagleville Road U-3060, Storrs, CT 06269, USA
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6
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Abstract
Horseradish peroxidase, and met hemoglobin, when intercalated in the galleries of alpha-Zr(IV) phosphate, show peroxidase activities at elevated temperatures (86-90 degrees C) and the rates increased to 2-3.6 times the rates observed at room temperature.
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Affiliation(s)
- C V Kumar
- Department of Chemistry, University of Connecticut, 55 N. Eagleville Road, Storrs, CT 06269-3060, USA.
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7
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Kumar CV, Tolosa LM. Interaction of hydrophobic probes with serum albumin - influence of the side chain and exciplex formation at the binding site. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100153a075] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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8
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Kumar CV, Lal JJ, Indira M. Postnatal changes in the brain lipids, glycolipids and gangliosides of rats exposed to arrack/ethanol during gestation and lactation. Indian J Physiol Pharmacol 2001; 45:421-7. [PMID: 11883147] [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] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Effects of exposure of an alcoholic beverage (arrack and its equivalent quantity of alcohol throughout pregnancy and lactation on brain lipids were investigated. Female rats were exposed to arrack (12.00 ml/kg body weigh/day) and ethanol (4.00 g/kg body weight day) before conception and throughout gestation and lactation. For 21 days pups were nursed by their own mothers, afterwards they were fed normal laboratory feed. We found that the level of cholesterol, phospholipids, triacylglycerols, free fatty acids, cerebrosides, ceramide dihexosides, ceramide polyhexosides, sulfatids,, mono and diglycosyl diglycerides and gangliosides were increased in the brain of 21st and 45th day pups. The alterations in the glycolipid profile of the brain persisted even when pups were not directly exposed to alcohol. These alterations in the glycolipid and ganglioside metabolism may be associated with the developmental abnormalities of the brain seen in FAS. The elevation produced in the glycolipid profile of arrack administered pups were more than that caused by its equivalent quantity of ethanol. This suggested an interaction of congeners in the arrack with the alcohol.
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Affiliation(s)
- C V Kumar
- Department of Biochemistry, University of Kerala, Thiruvananthapuram-695 581
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9
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Lal J, Kumar CV, Suresh MV, Indira M, Vijayammal PL. Effect of exposure to a country liquor (Toddy) during gestation on lipid metabolism in rats. Plant Foods Hum Nutr 2001; 56:133-143. [PMID: 11318502 DOI: 10.1023/a:1011101506830] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The objective of this study was to determine the effects of country liquor Toddy and its equivalent quantity of ethanol on lipid metabolism during gestation in rats. Female rats weighing an average of 125 g were exposed to Toddy (24.5 ml/body weight/day) and ethanol (0.52 ml/kg body weight/day) for 15 days before conception and throughout gestation. On the 19th day of gestation, altered liver function and hyperlipidemia was seen in both the treated groups. Altered liver function was evidenced by the increased activity of alcohol dehydrogenase, aldehyde dehydrogenase, glutamic oxaloacetic transaminase or aspartate amino transferase (GOT), glutamic pyruvic transaminase or alanine amino transferase (GPT) and gamma glutamyl transpeptidase (GGT). Hyperlipidemia was caused by increased biosynthesis and decreased degradation of lipids. The incorporation of 14C acetate in lipids and activities of HMG CoA reductase and lipogenic enzymes were elevated and activity of LPL and bile acids contents were decreased. Toddy treated rats were more severely affected than those receiving an equivalent quantity of ethanol. Toddy seemed to potentiate the toxicity induced by alcohol indicating the role of the nonethanolic portion. Hepatic functions were also affected.
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Affiliation(s)
- J Lal
- Department of Biochemistry, University of Kerala, Trivandrum, India
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10
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Lal JJ, Kumar CV, Suresh MV, Indira M, Vijayammal PL. Prenatal exposure of an alcoholic beverage (Arrack) on fetal lipid metabolism in rats. Indian J Physiol Pharmacol 2000; 44:273-80. [PMID: 10941614] [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] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
The objective of this study was to determine the effects of a country liquor (Arrack) and the equivalent quantity of ethanol on liver function and lipid metabolism in utero. Female rats of average weight 125 g were exposed to Arrack (12 ml/kg body weight/day) and ethanol (3.2 ml/kg body weight/day) for 15 days before conception and throughout gestation. On 13th day and 19th day of gestation, altered liver function and hyperlipidemia was seen in the fetus of both the treated groups. Altered liver function was evidenced by the increased activity of alcohol dehydrogenase and glutamic pyruvic transaminase or alanine amino transferase (GPT). Hyperlipidemia was caused by increased biosynthesis since the incorporation of 14C acetate to lipids and activities of HMG CoA reductase and lipogenic enzymes were elevated. Arrack seemed to potentiate the toxicity induced by alcohol indicating the role of non ethanolic portion. Hepatic functions of the 13th day fetuses were effected to a lesser degree than the 19th day hepatic liver.
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Affiliation(s)
- J J Lal
- Department of Biochemistry, University of Kerala, Kariyavattom, Trivandrum
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11
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Buranaprapuk A, Leach SP, Kumar CV, Bocarsly JR. Protein cleavage by transition metal complexes bearing amino acid substituents. Biochim Biophys Acta 1998; 1387:309-16. [PMID: 9840967 DOI: 10.1016/s0167-4838(98)00145-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In this report, we describe protein damage by a series of metal complexes that mediate the formation of hydroxyl radical. The protein targets used are bovine serum albumin (BSA) and carboxypeptidase A (CPA). BSA contains several electrostatic, hydrogen bonding and hydrophobic binding sites for potential interaction with the metal complexes, and CPA contains a specific phenylalanine binding site. The data presented in this study show that aromatic side chain damage and backbone cleavage occur to similar extents with all the complexes. Reasonable levels of backbone cleavage specificity can be attained with relatively few recognition elements, despite the fact that a diffusible radical mediates cleavage. Incorporation of additional recognition elements can enlarge the set of cleavage sites. We show that the chemical environment of the cleavage reaction, manipulated by using different buffers, can dramatically affect the outcome of the cleavage reaction. Our work suggests that backbone cleavage site is determined by three factors: the binding sites of the metal complexes, the role of reactive sites on the protein backbone, and the influence of the chemical environment on the reaction.
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Affiliation(s)
- A Buranaprapuk
- Department of Chemistry, The University of Connecticut, Storrs, CT 06269, USA
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12
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Kumar CV, Buranaprapuk A, Opiteck GJ, Moyer MB, Jockusch S, Turro NJ. Photochemical protease: site-specific photocleavage of hen egg lysozyme and bovine serum albumin. Proc Natl Acad Sci U S A 1998; 95:10361-6. [PMID: 9724708 PMCID: PMC27899 DOI: 10.1073/pnas.95.18.10361] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.1] [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: 11/18/2022] Open
Abstract
Site-specific photocleavage of hen egg lysozyme and bovine serum albumin (BSA) by N-(l-phenylalanine)-4-(1-pyrene)butyramide (Py-Phe) is reported. Py-Phe binds to lysozyme and BSA with binding constants 2.2 +/- 0.3 x 10(5) M-1 and 6.5 +/- 0.4 x 10(7) M-1, respectively. Photocleavage of lysozyme and BSA was achieved with high specificity when a mixture of protein, Py-Phe, and an electron acceptor, cobalt(III) hexammine (CoHA), was irradiated at 344 nm. Quantum yields of photocleavage of lysozyme and BSA were 0.26 and 0.0021, respectively. No protein cleavage was observed in the absence of Py-Phe, CoHA, or light. N-terminal sequencing of the protein fragments indicated a single cleavage site of lysozyme between Trp-108 and Val-109, whereas the cleavage of BSA was found to be between Leu-346 and Arg-347. Laser flash photolysis studies of a mixture of protein, Py-Phe, and CoHA showed a strong transient with absorption centered at approximately 460 nm, corresponding to pyrene cation radical. Quenching of the singlet excited state of Py-Phe by CoHA followed by the reaction of the resulting pyrenyl cation radical with the protein backbone may be responsible for the protein cleavage. The high specificity of photocleavage may be valuable in targeting specific sites of proteins with small molecules.
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Affiliation(s)
- C V Kumar
- Department of Chemistry, University of Connecticut, Storrs, CT 06269-3060, USA.
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13
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Lal JJ, Kumar CV, Suresh MV, Indira M, Vijayammal PL. Effect of coconut palm wine (Toddy) on carbohydrate metabolism in pregnant rats and fetuses. Plant Foods Hum Nutr 1997; 50:71-79. [PMID: 9198117 DOI: 10.1007/bf02436045] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The objective of this study was to determine the effects of an alcoholic beverage (Toddy) and the equivalent quantity of ethanol on carbohydrate metabolism in utero. Female rats were exposed to Toddy from coconut palm (24.5 ml/kg body weight/day) and ethanol (0.52 ml/kg body weight/day) for 15 days before conception and throughout gestation. On the 19th day of gestation, hypoglycemia was seen in both the treated groups, but it was more in the Toddy-treated group. Synthesis of glycogen was elevated on exposure to ethanol/Toddy but its degradation was enhanced only in alcohol-exposed rats. Key enzymes of citric acid cycle and gluconeogenesis were inhibited on administration of both alcohol and Toddy. Activity of glycolytic enzymes were increased. Toddy seemed to potentiate the toxicity induced by alcohol, indicating the additive effects of congeners.
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Affiliation(s)
- J J Lal
- Department of Biochemistry, University of Kerala, Kariyavattom, Trivandrum, India
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14
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Advant SJ, Braswell EH, Kumar CV, Kalonia DS. The effect of pH and temperature on the self-association of recombinant human interleukin-2 as studied by equilibrium sedimentation. Pharm Res 1995; 12:637-41. [PMID: 7479545 DOI: 10.1023/a:1016286920643] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [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: 01/25/2023]
Abstract
The self-association of recombinant human interleukin-2 (rhIL-2) in solution was investigated as a function of pH and temperature using equilibrium sedimentation. Studies were performed at pH 3.6, 6.5 and 8.2, at 1 degree C and 20 degrees C. A model assuming an ideal single molecular species describes the data observed at pH 6.5 at both temperatures. At pH 8.2, the data from both temperatures can be better described by a weak monomer-dimer association equilibrium. The values of the association constants obtained indicate the presence of less than 10% dimer at a concentration of 1 mg/ml at both temperatures. At pH 3.6, aggregates with a Z average molecular weight of over 35 times that of monomeric rhIL-2 were formed. The smallest associating species present under these conditions corresponds to the monomer, which produces aggregates with a wide range of molecular weights. The monomer appears to be in equilibrium with the smallest aggregates, in that a model describing an indefinite association fits the data obtained at the highest centrifugal speed. No model was found to successfully describe the association of the monomer into the much larger aggregates observed at lower speeds. This may be the result of the lack of rapid thermodynamic reversibility of the larger aggregates. Temperature was found to have no significant effect on the largest aggregates that were formed at pH 3.6.
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Affiliation(s)
- S J Advant
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs 06269, USA
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15
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Kumar CV, Coque JJ, Martín JF. Efficient Transformation of the Cephamycin C Producer
Nocardia lactamdurans
and Development of Shuttle and Promoter-Probe Cloning Vectors. Appl Environ Microbiol 1994; 60:4086-93. [PMID: 16349436 PMCID: PMC201940 DOI: 10.1128/aem.60.11.4086-4093.1994] [Citation(s) in RCA: 41] [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] [Indexed: 11/20/2022] Open
Abstract
A high transformation efficiency (1 × 10
5
to 7 × 10
5
transformants per μg of DNA) of
Nocardia lactamdurans
LC411 was obtained by direct treatment of mycelium with polyethylene glycol 1000 and cesium chloride. A variety of vectors from
Streptomyces lividans, Brevibacterium lactofermentum, Rhodococcus fascians
, and a
Nocardia (Amycolatopsis)
sp. were tested; transformants could be obtained only with vectors derived from an endogenous plasmid of the
Amycolatopsis
sp. strain DSM 43387. Vectors carrying the kanamycin resistance gene (
kan
) as a selective marker were constructed. The transformation procedure has been optimized by using one of these vectors (pULVK1) and studying the influence of the age of the culture, concentrations of cesium chloride and polyethylene glycol, amount of plasmid DNA, and nutrient supplementations of the growth medium. Versatile shuttle cloning vectors (pULVK2 and pULVK3) have been developed by subcloning the pBluescript KS(+) multiple cloning site or a synthetic polylinker containing several unique restriction sites (
Eco
RV,
Dra
I,
Bam
HI,
Sst
I,
Eco
RI, and
Hind
III). A second marker, the apramycin resistance gene (
amr
) has been added to the vectors (pULVK2A), allowing insertional inactivation of one of the markers while using the second one for selection. An alternative marker, the
amy
gene of
Streptomyces griseus
(pULAM2), which is easily detected by the release of extracellular amylase in transformants of
N. lactamdurans
carrying this vector, has been added. Two promoter-probe plasmids, pULVK4 and pULVK5, have been constructed, with the promoterless
xylE
gene as a reporter, for utilization in
N. lactamdurans
.
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Affiliation(s)
- C V Kumar
- Area of Microbiology, Faculty of Biology, University of León, 24071 León, Spain
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16
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Abstract
Binding of Leu-enkephalin and the enkephalin metabolite, tyrosine-glycine-glycine (TGG), to bovine serum albumin (BSA) was studied as a model to investigate protein peptide interactions. TGG and Leu-enkephalin quench the tryptophyl fluorescence of BSA. Stern-Volmer quenching constants were typically in the range of 40 to 300 M-1, depending on the experimental conditions. The addition of Cu(II) or Ni(II) did not change the quenching constant, indicating that TGG does not compete for the metal binding sites on BSA. From fluorescence quenching studies with TGG, tyrosyl-glycine, tyrosine and glycyl-glycine, it was concluded that the presence of the tyrosine residue is required for the observed quenching. The phenolic group in tyrosine accounted for the quenching mechanism because phenol was efficient in quenching BSA fluorescence, whereas phenylalanine had no detectable effect. A large solvent isotope effect on the quenching constant of phenol and TGG with BSA strongly suggests an active role of the -OH functionality in the quenching mechanism.
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Affiliation(s)
- S Jain
- School of Pharmacy, University of Connecticut, Storrs 06269-2092
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17
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Friedman AE, Kumar CV, Turro NJ, Barton JK. Luminescence of ruthenium(II) polypyridyls: evidence for intercalative binding to Z-DNA. Nucleic Acids Res 1991; 19:2595-602. [PMID: 2041736 PMCID: PMC328175] [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: 12/29/2022] Open
Abstract
Photophysical studies have been undertaken to characterize the binding interactions of enantiomers of Ru(phen)3(2+), Ru(DIP)3(2+), and racemic Ru(bpy)2dppz2+ (where phen = 1,10-phenanthroline, DIP = 4,7-diphenylphenanthroline, and dppz = dipyridophenazine) with Z-form poly d(GC). Parallel enhancements in steady state luminescent intensity and a lengthening of luminescent lifetimes are seen for ruthenium enantiomers with Z-DNA as for B-DNA but with enantioselectivities reversed. Greater enhancements are seen for delta-isomers with the right-handed helix but for lambda-isomers with the left-handed helix. Ru(bpy)2dppz2+, an avid intercalator in B-DNA, displays no luminescence free in aqueous solution, but luminesces brightly bound to either B- or Z-poly d(GC). Stern-Volmer quenching studies also support the enantioselective preference in binding to B-DNA by delta-isomers and a reversal with binding to Z-DNA preferentially by the lambda-isomers. Steady state polarization studies indicate a rigid association of the complexes with both B- and Z-DNA on the time-scale of their emission and again with symmetrical enantioselectivities for the left and right-handed helices. Given the well characterized intercalative association of the complexes with B-DNA, the parallel results seen here with Z-DNA point strongly to a comparable intercalative association with the Z-form helix. That molecules may interact with Z-DNA through intercalation has not been demonstrated previously and now requires consideration in describing the range of interactions of small molecules and proteins with Z-DNA.
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Affiliation(s)
- A E Friedman
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena 91125
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18
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Abstract
DNA-mediated long-range electron transfer from photoexcited 1,10-phenanthroline complexes of ruthenium, Ru(phen)2(3)+, to isostructural complexes of cobalt(III), rhodium(III), and chromium(III) bound along the helical strand. The efficiency of transfer depended upon binding mode and driving force. For a given donor-acceptor pair, surface-bound complexes showed greater rate enhancements than those that were intercalatively bound. Even in rigid glycerol at 253 K, the rates for donor-acceptor pairs bound to DNA remained enhanced. For the series of acceptors, the greatest enhancement in electron-transfer rate was found with chromium, the acceptor of intermediate driving force. The DNA polymer appears to provide an efficient intervening medium to couple donor and acceptor metal complexes for electron transfer.
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Affiliation(s)
- M D Purugganan
- Department of Chemistry, Columbia University, New York, NY 10027
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Abstract
DNA-mediated long-range electron transfer from photoexcited 1,10-phenanthroline complexes of ruthenium, Ru(phen)2(3)+, to isostructural complexes of cobalt(III), rhodium(III), and chromium(III) bound along the helical strand. The efficiency of transfer depended upon binding mode and driving force. For a given donor-acceptor pair, surface-bound complexes showed greater rate enhancements than those that were intercalatively bound. Even in rigid glycerol at 253 K, the rates for donor-acceptor pairs bound to DNA remained enhanced. For the series of acceptors, the greatest enhancement in electron-transfer rate was found with chromium, the acceptor of intermediate driving force. The DNA polymer appears to provide an efficient intervening medium to couple donor and acceptor metal complexes for electron transfer.
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