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Selvaraj R, Shanmugam K, Selvaraj P, Nagasai BP, Balasubramanian V. Optimization of Process Parameters of Rotary Friction Welding of Low Alloy Steel Tubes Using Response Surface Methodology. Forces in Mechanics 2023. [DOI: 10.1016/j.finmec.2023.100175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Shanmugam K, Nirmala A, Parthiban P, Pitchiah Kumar M, Dhanam C, Ganesh S, Babu K, Salaikarthikaiyan T. Safety and Efficacy of Siddha Medicine preparation in the management of COVID-19: A Prospective Randomised Open Label Study. J Ayurveda Integr Med 2022; 13:100597. [PMID: 35677618 PMCID: PMC9163045 DOI: 10.1016/j.jaim.2022.100597] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 09/16/2021] [Accepted: 05/27/2022] [Indexed: 10/26/2022] Open
Abstract
Background The use of complementary and alternative medicine (CAM) therapies has surged since the spread of COVID-19 pandemic. However, the efficacy and safety of these CAM therapies remains majorly unexplored. Objective of the current study is to understand the efficacy and safety of one such traditional CAM therapy of South India, known as 'Siddha' system of medicine, in the management for the COVID-19 patients. Methods We conducted a randomised, controlled, open label trial in patients hospitalized with SARS-CoV-2 infection who had an oxygen saturation of 90% or more while breathing ambient air. Patients were randomized into two groups in a 1:1 ratio to either intervention group, receiving seven days of siddha medicine (Intervention group; n=50) or standard care (control group; n=50). The primary end point was clinical markers and patient recovery status on day 8. Results A total of 100 patients with confirmed COVID-19 with average age of 37 yrs (interquartile range, 28-49) participated in the study. There was no statsistically difference between groups at baseline (P>0.05). After intervention, patients in the intervention group had statistically (P<0.05) significant reduction in the symptoms when compared to standard care. By end of the intervention period, 6 patients (12%) were hospitalized in the control group and none of them were reported for intervention group. Conclusion Among patients with mild to moderate COVID-19, 7 days of siddha medicine showed a significant reduction in the clinical sysmptoms and requirement of hospitalisation, with no adverse events. Therefore, the particular siddha medicine preparation could be used safely and effectively for the management of COVID-19 patients. Clinical Trial Registration CTRI/2020/08/026999.
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Affiliation(s)
- K Shanmugam
- Department of Indian Medicine & Homeopathy, Govt of Tamilnadu, India
| | - A Nirmala
- Govt.Medical college & ESI Hospital, Singanallur, Coimbatore
| | - P Parthiban
- Department of Indian Medicine & Homeopathy, Govt of Tamilnadu, India
| | - M Pitchiah Kumar
- Department of Indian Medicine & Homeopathy, Govt of Tamilnadu, India
| | - C Dhanam
- Department of Indian Medicine & Homeopathy, Govt of Tamilnadu, India
| | - S Ganesh
- Department of Indian Medicine & Homeopathy, Govt of Tamilnadu, India
| | - K Babu
- Department of Indian Medicine & Homeopathy, Govt of Tamilnadu, India
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Shanmugam K, Vanathi B. Newton Algorithm Based DELM for Enhancing Offline Tamil Handwritten Character Recognition. INT J PATTERN RECOGN 2022. [DOI: 10.1142/s0218001422500203] [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: 11/18/2022]
Abstract
Numerous research based on offline Tamil recognition deals only with few Tamil characters since it becomes extremely complicated in distinguishing small variations in large handwritten document. The writer’s complexity affects the overall formation of the characters. Such types of complexities are due to discontinuation of structures, unnecessary over loops, variation in shapes as well as irregular curves. This complex issue results in enhanced error value rate. Therefore, to conquer such issues, this paper proposes a novel approach to enhance the offline Tamil handwritten character recognition by utilizing four principal steps: pre-processing, segmentation, feature extraction and classification. For optimal segmentation of Tamil characters, this paper utilizes the Tsallis entropy approach-based atom search (TEAS) optimization algorithm. Then a Newton algorithm based deep convolution extreme learning (DELM) approach is utilized for the extraction and classification of input images. Finally, experiments are carried out for numerous Tamil handwritten recognition-based approaches. The proposed Tamil character recognition utilizes the datasets of isolated Tamil handwritten characters established by HP lab India to evaluate the efficiency of the system.
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Affiliation(s)
- K. Shanmugam
- Department of Computer Science and Engineering, SRM Valliammai Engineering College, Chennai, India
| | - B. Vanathi
- Department of Computer Science and Engineering, SRM Valliammai Engineering College, Chennai, India
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Balasubramanian AR, Vasudevan S, Shanmugam K, Lévesque CM, Solomon AP, Neelakantan P. Combinatorial effects of trans-cinnamaldehyde with fluoride and chlorhexidine on Streptococcus mutans. J Appl Microbiol 2020; 130:382-393. [PMID: 32707601 DOI: 10.1111/jam.14794] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [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: 05/29/2020] [Revised: 07/06/2020] [Accepted: 07/18/2020] [Indexed: 01/03/2023]
Abstract
AIMS The aim of this study was to investigate the effects of trans-cinnamaldehyde (TC) and its synergistic activity with chlorhexidine (CHX) and fluoride against Streptococcus mutans. METHODS AND RESULTS Streptococcus mutans UA159 was treated with TC alone and in combination with CHX or sodium fluoride. The synergy profile was analysed using the Zero Interaction Potency model. TC showed strong synergism (synergy score of 21·697) with CHX, but additive effect (synergy score of 5·298) with fluoride. TC and the combinations were tested for acid production (glycolytic pH drop) and biofilm formation by S. mutans, and nitric oxide production in macrophages. TC significantly inhibited sucrose-dependent biofilm formation and acid production by S. mutans. Mechanistic studies were carried out by qRT-PCR-based transcriptomic studies which showed that TC acts by impairing genes related to metabolism, quorum sensing, bacteriocin expression, stress tolerance and biofilm formation. CONCLUSIONS trans-Cinnamaldehyde potentiates CHX and sodium fluoride in inhibiting S. mutans biofilms and virulence through multiple mechanisms. This study sheds significant new light on the potential to develop TC as an anti-caries treatment. SIGNIFICANCE AND IMPACT OF THE STUDY Oral diseases were classified as a 'silent epidemic' in the US Surgeon General's Report on Oral Health. Two decades later, >4 billion people are still affected worldwide by caries, having significant effects on the quality of life. There is an urgent need to develop novel compounds and strategies to combat dental caries. Here, we prove that TC downregulates multiple pathways and potentiates the CHX and fluoride to prevent S. mutans biofilms and virulence. This study sheds significant new light on the potential to develop TC in combination with CHX or fluoride as novel treatments to arrest dental caries.
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Affiliation(s)
- A R Balasubramanian
- Quorum Sensing Laboratory, Centre for Research in Infectious Diseases (CRID), School of Chemical and Biotechnology, SASTRA Deemed to be University, Thanjavur, India
| | - S Vasudevan
- Quorum Sensing Laboratory, Centre for Research in Infectious Diseases (CRID), School of Chemical and Biotechnology, SASTRA Deemed to be University, Thanjavur, India
| | - K Shanmugam
- Quorum Sensing Laboratory, Centre for Research in Infectious Diseases (CRID), School of Chemical and Biotechnology, SASTRA Deemed to be University, Thanjavur, India
| | - C M Lévesque
- Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
| | - A P Solomon
- Quorum Sensing Laboratory, Centre for Research in Infectious Diseases (CRID), School of Chemical and Biotechnology, SASTRA Deemed to be University, Thanjavur, India
| | - P Neelakantan
- Faculty of Dentistry, The University of Hong Kong, Hong Kong, Hong Kong SAR
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Rohr UP, Herrmann P, Ilm K, Zhang H, Lohmann S, Reiser A, Muranyi A, Smith J, Burock S, Osterland M, Leith K, Singh S, Brunhoeber P, Bowermaster R, Tie J, Christie M, Wong HL, Waring P, Shanmugam K, Gibbs P, Stein U. Prognostic value of MACC1 and proficient mismatch repair status for recurrence risk prediction in stage II colon cancer patients: the BIOGRID studies. Ann Oncol 2017; 28:1869-1875. [DOI: 10.1093/annonc/mdx207] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
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Aziz D, Etemadmoghadam D, Au-Yeung G, Muranyi A, Gresshoff I, Christie M, Hutchinson R, Ferraro D, Stanislaw S, Henricksen L, Tubbs A, Shanmugam K, Bowtell D, Waring P. 298O The clinical significance of deregulated cyclin E1 in high grade serous ovarian cancer (HGSOC). Ann Oncol 2016. [DOI: 10.1093/annonc/mdw585.002] [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: 11/13/2022] Open
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Aziz D, Etemadmoghadam D, Au-Yeung G, Muranyi A, Gresshoff I, Christie M, Hutchinson R, Ferraro D, Stanislaw S, Henricksen L, Tubbs, Shanmugam K, Bowtell D, Waring P. 298O The clinical significance of deregulated cyclin E1 in high grade serous ovarian cancer (HGSOC). Ann Oncol 2016. [DOI: 10.1016/s0923-7534(21)00456-7] [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: 11/27/2022] Open
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Gibbs P, Tie J, Ghosh P, Muranyi A, Brunhoeber P, Singh S, LaFluer B, Xu C, Leith K, Tran B, Desai J, Martinez R, Goel A, Waring P, Hu S, Teichgraeber V, Rohr U, Ridder R, Shanmugam K. 2160 GIV as a novel marker of recurrence risk in MMR proficient stage II colon cancer. Eur J Cancer 2015. [DOI: 10.1016/s0959-8049(16)31081-4] [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: 10/22/2022]
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Gibbs P, Ghosh P, Waring P, Lafleur B, Muranyi A, Singh S, Brunhoeber P, Tie J, Tran B, Desai J, Martinez R, Janssen K, Goel A, Hu S, Teichgräber V, Rohr U, Ridder R, Shanmugam K. Giv As a Novel Prognostic Marker in Stage Ii Colon Cancer. Ann Oncol 2014. [DOI: 10.1093/annonc/mdu333.71] [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: 11/13/2022] Open
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Abstract
Aim: The aim of this work was to determine the frequency and nature of oral manifestations in a hypertensive patient. Materials and Methods: The study sample consisted of 465 known hypertensive patients, between the age group of 20-80 years of which 250 patients were males and 215 were females. 105 were between the age group of 1-40 years, 136 in 41-50 years, 110 in 51-60 years, and 114 in 60 and above year of age. Data were statistically analyzed Student's t-test. Results: 79.14% of the patients presented with Russell's periodontal index score ranging from 2- 4.9 which suggested an established periodontal lesion. The risk factors for old men and women to develop hypertension were 90%, among those who survived to ages 65 to 89 years. Conclusion: The frequency of potential oral manifestations in patients with hypertension was significantly high, thus showing an association of gingival and periodontal pathology in hypertensive patients
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Affiliation(s)
- Prashant Kumar
- Department of Oral Pathology, S.Nijalingappa Institute of Dental Sciences, Gulbarga, India
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Desai J, Day F, Muranyi A, Singh S, Shanmugam K, Grogan T, Gibbs P, Williams D, Sieber O, Waring P. A Highly Sensitive Immunohistochemical Assay to Detect Braf V600E Mutations in Patients with Colorectal Cancer. Ann Oncol 2012. [DOI: 10.1093/annonc/mds406] [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: 11/12/2022] Open
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Roy LD, Sahraei M, Subramani DB, Besmer D, Nath S, Tinder TL, Bajaj E, Shanmugam K, Lee YY, Hwang SIL, Gendler SJ, Mukherjee P. MUC1 enhances invasiveness of pancreatic cancer cells by inducing epithelial to mesenchymal transition. Oncogene 2010; 30:1449-59. [PMID: 21102519 PMCID: PMC3063863 DOI: 10.1038/onc.2010.526] [Citation(s) in RCA: 206] [Impact Index Per Article: 14.7] [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] [Indexed: 02/07/2023]
Abstract
Increased motility and invasiveness of pancreatic cancer cells are associated with epithelial to mesenchymal transition (EMT). Snai1 and Slug are zinc-finger transcription factors that trigger this process by repressing E-cadherin and enhancing vimentin and N-cadherin protein expression. However, the mechanisms that regulate this activation in pancreatic tumors remain elusive. MUC1, a transmembrane mucin glycoprotein, is associated with the most invasive forms of pancreatic ductal adenocarcinomas (PDA). In this study, we show that over expression of MUC1 in pancreatic cancer cells triggers the molecular process of EMT, which translates to increased invasiveness and metastasis. EMT was significantly reduced when MUC1 was genetically deleted in a mouse model of PDA or when all seven tyrosines in the cytoplasmic tail of MUC1 were mutated to phenylalanine (mutated MUC1 CT). Using proteomics, RT-PCR and western blotting, we revealed a significant increase in vimentin, Slug and Snail expression with repression of E-Cadherin in MUC1-expressing cells compared with cells expressing the mutated MUC1 CT. In the cells that carried the mutated MUC1 CT, MUC1 failed to co-immunoprecipitate with β-catenin and translocate to the nucleus, thereby blocking transcription of the genes associated with EMT and metastasis. Thus, functional tyrosines are critical in stimulating the interactions between MUC1 and β-catenin and their nuclear translocation to initiate the process of EMT. This study signifies the oncogenic role of MUC1 CT and is the first to identify a direct role of the MUC1 in initiating EMT during pancreatic cancer. The data may have implications in future design of MUC1-targeted therapies for pancreatic cancer.
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Affiliation(s)
- L D Roy
- Department of Biology, University of North Carolina Charlotte, Charlotte, NC 28223, USA
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Scariah KJ, Usha KM, Narayanaswamy K, Shanmugam K, Sastri KS. Evaluation of isomeric composition of resol-type phenol formaldehyde matrix resins for silica-phenolic composites and its effect on cure characteristics of the resin. J Appl Polym Sci 2003. [DOI: 10.1002/app.12918] [Citation(s) in RCA: 12] [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] [Indexed: 11/06/2022]
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Shanmugam K. Testing the Bolam Test: consequences of recent developments. Singapore Med J 2002; 43:7-11. [PMID: 12008769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
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Shanmugam K, Subrahmanyam S, Tarakad SV, Kodandapani N, Stanly DF. 2,4-Toluene diamines--their carcinogenicity, biodegradation, analytical techniques and an approach towards development of biosensors. ANAL SCI 2001; 17:1369-74. [PMID: 11783783 DOI: 10.2116/analsci.17.1369] [Citation(s) in RCA: 9] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
2,4-Toluene diamine (TDA), a class A carcinogen, is a major raw material for the production of toluene diisocyanate (TDI), which is one of the precursors for the production of polyurethane foams (PU). This review deals with 2,4-toluene diamine's (TDA) carcinogenicity, analytical techniques, biodegradation and use as a biosensor for biogenic and synthetic amines, emphasizing various carcinogenicity studies by 2,4-TDA on animals and humans. This review reports some publications of the analysis of body fluid samples of workers from a PU producing factory for presence of TDA and TDI, since TDI gets absorbed into the worker's body, getting metabolized into TDA. Biodegradations of 2,4-TDA by various researchers are reported and also our own research experience with biodegradation of 2,4-TDA using Aspergillus nidulans isolated from soil site at a polyurethane foam dumping site have been discussed in this review. Biosensors for various biogenic and synthetic amines are discussed.
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Affiliation(s)
- K Shanmugam
- Department of Chemical Engineering, Anna University, Chennai, India.
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Bhaduri A, Gill T, Albert S, Shanmugam K, Iyer D. Repair welding of cracked steam turbine blades using austenitic and martensitic stainless-steel consumables. Nuclear Engineering and Design 2001. [DOI: 10.1016/s0029-5493(00)00439-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Subrahmanyam S, Kodandapani N, Shanmugam K, Moovarkumuthalvan K, Jeyakumar D, Subramanian TV. Cyclic voltammetric measurements of growth of Aspergillus terreus. ANAL SCI 2001; 17:481-4. [PMID: 11990561 DOI: 10.2116/analsci.17.481] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [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: 11/23/2022]
Abstract
A detailed study using the cyclic voltammogram was done on the live cells of Aspergillus terreus. The peak current values were obtained for different days of growth and plotted against time. The response of cyclic voltammogram showed the phases of the growth of the fungus. The growth curve obtained matched well with the conventional methodology, which assesses the increase of dry weight of the organisms against time. The electrochemical method is more advantageous because it is easy to assess and consumes less time. Further the electrochemical method clearly shows the decline phase which is generally not very defined in the conventional method of assessment of the growth curve. It was confirmed by further experiments that the metabolites were responsible for the anodic peak and not the biomass. Further work is in progress in order to analyze the metabolite(s) that is/are responsible for the anodic peak.
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Affiliation(s)
- S Subrahmanyam
- Department of Chemical Engineering, A. C. College of Technology, Anna University, Madras, India.
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Burgess K, Han I, Zhang A, Zheng WH, Shanmugam K, Featherstone MS, Saragovi HU. DiSSiMiL: Diverse Small Size Mini-Libraries applied to simple and rapid epitope mapping of a monoclonal antibody. J Pept Res 2001; 57:68-76. [PMID: 11168890 DOI: 10.1034/j.1399-3011.2001.00786.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Methods for screening protein-protein interactions are useful in protein science and for the generation of drug leads. We set out to develop a simplified assay to rapidly test protein-protein interactions, with a library of 400 pentapeptides comprising the 20 natural amino acids at two variable positions followed by three glycines (NH2-X1X2GGG). The library was used to identify the epitope of monoclonal antibody (mAb) 10D11 directed against the HOXD4 protein. Three pentapeptide 'hits' were selected (VYGGG, PWGGG and WKGGG) from direct binding assays screening for pentapeptide-mAb interactions; and from assays using pentapeptides in solution to competitively block HOXD4-mAb interactions. Alignment of the three 'hit' pentapeptides to the HOXD4 sequence predicts the mAb 10D11 epitope as NH2-VYPWMK. Synthesis of NH2-VYPWMK hexapeptide confirmed this prediction; and an alanine scan of HOXD4 ablated binding by mAb 10D11 when amino acids in the putative epitope were mutated. We propose that these simplified but diverse libraries can be used for rapid epitope mapping of some mAbs, and for generating lead small peptide analogs that interfere with receptor-ligand or other protein-protein interactions, or with enzymatic activity.
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Affiliation(s)
- K Burgess
- Department Chemistry, Texas A&M University, College Station, USA
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Subrahmanyam S, Shanmugam K, Madhav VM, Murugesan M, Subramanian TV, Jeyakumar D. Assessment of growth of Fusarium solani by cyclic voltammetry and possible bioanalytical applications. Analyst 2000; 125:2166-8. [PMID: 11219046 DOI: 10.1039/b008342i] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [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: 11/21/2022]
Abstract
Fusarium solani, the fungus isolated from polyurethane waste scraps, was studied for its voltammetric response. The peak current values were obtained for different days and were plotted against time. This electrochemical method based on the voltammetric response showed all the four phases of the growth of the fungus. The growth curve obtained matched well with the conventional methodology, which is obtained by assessing the increase of dry weight of the organisms against time. The electrochemical method is more advantageous than the conventional method because the conventional method is very time consuming and difficult to work with. Further, the electrochemical method clearly shows the decline phase, which is generally not very well defined in the conventional method of assessment of the growth curve. It was confirmed by further experiments that the metabolites were responsible for the anodic peak and not the fungal biomass. Identification of the metabolites that are responsible for the anodic peak is presently being studied.
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Affiliation(s)
- S Subrahmanyam
- Department of Chemical Engineering, Alagappa College of Technology, Anna University, Madras 600 025, Tamil Nadu State, India.
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Shanmugam K, Green NC, Rambaldi I, Saragovi HU, Featherstone MS. PBX and MEIS as non-DNA-binding partners in trimeric complexes with HOX proteins. Mol Cell Biol 1999; 19:7577-88. [PMID: 10523646 PMCID: PMC84774 DOI: 10.1128/mcb.19.11.7577] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/1999] [Accepted: 07/21/1999] [Indexed: 11/20/2022] Open
Abstract
HOX, PBX, and MEIS transcription factors bind DNA through a homeodomain. PBX proteins bind DNA cooperatively as heterodimers with MEIS family members and also with HOX proteins from paralog groups 1 to 10. MEIS proteins cooperatively bind DNA with ABD-B class HOX proteins of groups 9 and 10. Here, we examine aspects of dimeric and higher-order interactions between these three homeodomain classes. The most significant results can be summarized as follows. (i) Most of PBX N terminal to the homeodomain is required for efficient cooperative binding with HOXD4 and HOXD9. (ii) MEIS and PBX proteins form higher-order complexes on a heterodimeric binding site. (iii) Although MEIS does not cooperatively bind DNA with ANTP class HOX proteins, it does form a trimer as a non-DNA-binding partner with DNA-bound PBX-HOXD4. (iv) The N terminus of HOXD4 negatively regulates trimer formation. (v) MEIS forms a similar trimer with DNA-bound PBX-HOXD9. (vi) A related trimer (where MEIS is a non-DNA-binding partner) is formed on a transcriptional promoter within the cell. (vii) We observe an additional trimer class involving non-DNA-bound PBX and DNA-bound MEIS-HOXD9 or MEIS-HOXD10 heterodimers that is enhanced by mutation of the PBX homeodomain. (viii) In this latter trimer, PBX is likely to contact both MEIS and HOXD9/D10. (ix) The stability of DNA binding by all trimers is enhanced relative to the heterodimers. These findings suggest novel functions for PBX and MEIS in modulating the function of DNA-bound MEIS-HOX and PBX-HOX heterodimers, respectively.
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Affiliation(s)
- K Shanmugam
- McGill Cancer Centre, McGill University, Montreal, Quebec, Canada H3G 1Y6
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Abstract
Hox genes encode transcription factors that are major determinants of embryonic patterning. Recently, we and others have shown that specific recognition of target sites in DNA is partly achieved through cooperative interaction with the extradenticle/pre-B-cell transformation-related gene (EXD/PBX) family of homeodomain-containing proteins. This interaction is mediated by the YPWM motif present N-terminal to the homeodomain in HOX proteins. In the present study, we use YPWM peptides to confirm the importance of this motif for mediating HOX/PBX interactions. We also used a novel monoclonal antibody directed against the YPWM to show that occlusion of this motif abrogates cooperativity with PBX. In addition, we present evidence that residues flanking the YPWM, both N-terminally and C-terminally, stabilize the HOX.PBX cooperative complex. Because these flanking residues are also conserved among paralogs, they are likely to help distinguish the specificity of HOX/PBX interactions. Our data further show that the relative importance of individual residues within and flanking the YPWM is dependent on the identity of position 6 of the cooperative binding site (TGATTNATGG). These results suggest that interactions between PBX and the YPWM motif are modified by a base pair predicted to contact the N-terminal arm of the HOX homeodomain.
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Affiliation(s)
- K Shanmugam
- McGill Cancer Centre, McGill University, Montreal, Quebec H3G 1Y6, Canada
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Shanmugam K, Hanic-Joyce PJ, Joyce PB. Purification and characterization of a tRNA nucleotidyltransferase from Lupinus albus and functional complementation of a yeast mutation by corresponding cDNA. Plant Mol Biol 1996; 30:281-295. [PMID: 8616252 DOI: 10.1007/bf00020114] [Citation(s) in RCA: 8] [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: 05/22/2023]
Abstract
ATP (CTP):tRNA nucleotidyltransferase (EC 2.7.7.25) was purified to apparent homogeneity from a crude extract of Lupinus albus seeds. Purification was accomplished using a multistep protocol including ammonium sulfate fractionation and chromatography on anion-exchange, hydroxylapatite and affinity columns. The lupin enzyme exhibited a pH optimum and salt and ion requirements that were similar to those of tRNA nucleotidyltransferases from other sources. Oligonucleotides, based on partial amino acid sequence of the purified protein, were used to isolate the corresponding cDNA. The cDNA potentially encodes a protein of 560 amino acids with a predicted molecular mass of 64 164 Da in good agreement with the apparent molecular mass of the pure protein determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The size and predicted amino acid sequence of the lupin enzyme are more similar to the enzyme from yeast than from Escherichia coli with some blocks of amino acid sequence conserved among all three enzymes. Functionality of the lupin cDNA was shown by complementation of a temperature-sensitive mutation in the yeast tRNA nucleotidyltransferase gene. While the lupin cDNA compensated for the nucleocytoplasmic defect in the yeast mutant it did not enable the mutant strain to grow at the non-permissive temperature on a non-fermentable carbon source.
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Affiliation(s)
- K Shanmugam
- Department of Chemistry, Concordia University, Montreal, Quebec, Canada
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Abstract
Series of 4-(3-dimethylaminopropyl)-4-hydroxyindeno[1,2-c]pyrazoles and 4-(1-methyl-4-piperidyl)-4-hydroxyindeno[1,2-c-]pyrazoles were synthesized and identified. The compounds were evaluated as potential CNS agents using spontaneous and forced motor activity in mice as an initial test. 2-Ethyl-3-methyl-4-(1-methyl-4-piperidyl)-4-hydroxyindeno[1,2-c]pyrazole possessed significant biological activity.
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