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Joshi PR, Sankaran K. P⋯N type pnicogen bonding in phosphorus trichloride–pyridine adduct: A matrix isolation infrared, DFT and ab initio study. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2020.128408] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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2
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Mishra S, P VA, Sridhar M, Pandey N, Sankaran K, Joseph M. Characterization of gamma irradiated PUREX solvent – A systematic study. SEP SCI TECHNOL 2020. [DOI: 10.1080/01496395.2019.1594895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
| | | | - M. Sridhar
- Fluoroorganics Division, CSIR-Indian Institute of Chemical Technology, Hyderabad, India
| | - N.K. Pandey
- Reprocessing R&D Division, IGCAR, Kalpakkam, India
| | - K. Sankaran
- Materials Chemistry & Metal Fuel Cycle Group, IGCAR, Kalpakkam, India
| | - M. Joseph
- Materials Chemistry & Metal Fuel Cycle Group, IGCAR, Kalpakkam, India
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3
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Kannabiran G, Sankaran K. Evaluation of Determinants of Software Quality in Offshored Software Projects. International Journal of Information Technology Project Management 2020. [DOI: 10.4018/ijitpm.2020010103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Successful offshoring engagements of Indian software vendors is increasingly dependent upon the quality of the projects delivered rather than cost considerations. However, delivering quality software is reliant on effective management of various organizational, technological and people aspects. This research is to identify and evaluate the determinants of quality on software projects delivered by vendors through offshoring. Data related to recently completed projects were collected through a survey of 440 project managers from Indian vendors. Based on structural equation modeling, the authors analyze the influence determinants on specific product quality attributes. It is found that, out of six determinants, technical infrastructure and process maturity have significant influence on most of the attributes of quality in offshored IS projects from India. The authors provide a set of implications for practice and directions for further research.
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Affiliation(s)
| | - K. Sankaran
- Independent Management Consultant, Chennai, India
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4
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Paramasivam OR, Trivedi S, Sangith N, Sankaran K. Active sulfite oxidase domain of Salmonella enterica pathogenic protein small intestine invasive factor E (SiiE): a potential diagnostic target. Appl Microbiol Biotechnol 2019; 103:5679-5688. [PMID: 31104097 DOI: 10.1007/s00253-019-09894-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 04/23/2019] [Accepted: 04/29/2019] [Indexed: 10/26/2022]
Abstract
Serovars of Salmonella enterica are common food-borne bacterial pathogens. Salmonella typhi, which causes typhoid, is the most dangerous of them. Though detailed molecular pathogenesis studies reveal many virulence factors, inability to identify their biochemical functions hampers the development of diagnostic methods and therapeutic leads. Lack of quicker diagnosis is an impediment in starting early antibiotic treatment to reduce the severe morbidity and mortality in typhoid. In this study, employing bioinformatic prediction, biochemical analysis, and recombinantly cloning the active region, we show that extracellularly secreted virulence-associated protein, small intestinal invasion factor E (SiiE), possesses a sulfite oxidase (SO) domain that catalyzes the conversion of sodium sulfite to sodium sulfate using tungsten as the cofactor. This activity common to Salmonella enterica serovars seems to be specific to them from bioinformatic analysis of available bacterial genomes. Along with the ability of this large non-fimbrial adhesin of 600 kDa binding to sialic acid on the host cells, this activity could aid in subverting the host defense mechanism by destroying sulfites released by the immune cells and colonize the host gastrointestinal epithelium. Being an extracellular enzyme, it could be an ideal candidate for developing diagnostics of S. enterica, particularly S. typhi.
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Affiliation(s)
| | - Swati Trivedi
- Centre for Biotechnology, Anna University, Chennai, 600020, India
| | - Nikhil Sangith
- Centre for Biotechnology, Anna University, Chennai, 600020, India.
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5
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Kumar S, Maji S, Sundararajan K, Sankaran K. Development of a simple spectrophotometric method to estimate uranium concentration in LiCl–KCl matrix. J Radioanal Nucl Chem 2019. [DOI: 10.1007/s10967-019-06471-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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6
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Reimche L, Sankaran K, Hindmarsh K, Kasian G, Gorecki D, Tan L. Chloral Hydrate Sedation in Neonates and Infants -
Clinical and Pharmacologic Considerations. ACTA ACUST UNITED AC 2019. [DOI: 10.1159/000480965] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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7
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Toye JM, Yang J, Sankaran K. Narcotics and sedatives use in the mechanical ventilation in preterm infants: Predictors and outcome. J Neonatal Perinatal Med 2019; 12:135-141. [PMID: 30614810 DOI: 10.3233/npm-17157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Mechanical ventilation (MV) causes discomfort but whether it causes pain remains controversial. Around the world neonatal intensive care units (NICU) often utilize narcotics and/or sedatives during MV of vulnerable infants yet the association with adverse neonatal outcomes has not been adequately addressed. OBJECTIVE Test for associations between the use of narcotics/sedatives during MV and mortality/morbidity in preterm infants in a large infant cohort in Canada. DESIGN/METHODS Preterm infants born <35 weeks gestational age (GA) requiring MV for >24 hrs were identified retrospectively from the Canadian Neonatal Network database, 2010-12. Infants were categorized according to whether they received narcotics/sedatives for greater than 24 hours concurrently with MV. Infants were excluded if moribund on admission, had major congenital anomalies, diagnoses where narcotic administration is routine and suspected seizures. Multivariable logistic and linear regression analysis tested for association of narcotics/sedatives use during MV with mortality/morbidity (nosocomial infections, BPD, ROP, IVH) and length of MV. RESULTS After exclusions the cohort included 2672 infants; 467(17%) exposed only to narcotics 101(4%) only to sedatives and 299(11%) to both. All models were adjusted for GA, gender, small for GA, SNAP-II score >20, multiple births, delivery mode, outborn, PDA status, MV type, use of high flow, muscle relaxant use, indwelling lines, caffeine and surfactant therapy. The composite mortality/morbidity, and MV days were significantly higher for MV infants exposed to narcotics, sedatives or both compared to infants not exposed. CONCLUSION Mounting evidence of the adverse short and long-term impacts of narcotics/sedatives during MV supports the need for further work in alternative therapies.
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Affiliation(s)
- J M Toye
- University of Alberta, Division of Neonatology, Department of Pediatrics, Alberta, Canada
| | - J Yang
- Mount Sinai Hospital, Maternal-Infant Care Research Centre, Ontario, Canada
| | - K Sankaran
- Department of Pediatrics, University of Saskatchewan, Division of Neonatology, SK, Canada
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8
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Kumar S, Maji S, Gopakumar G, Joseph M, Sundararajan K, Sankaran K. Luminescent versus non-luminescent uranyl–picolinate complexes. J Radioanal Nucl Chem 2018. [DOI: 10.1007/s10967-018-6305-3] [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: 10/28/2022]
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9
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Ramanathan N, Sarkar S, Sundararajan K, Chandrasekar A, Sankaran K, Suresh A. Influence of Branching on the Conformational Space: Case Study of Tri-sec-butyl Phosphate Using Matrix Isolation Infrared Spectroscopy and DFT Computations. J Phys Chem A 2018; 122:8229-8242. [DOI: 10.1021/acs.jpca.8b08157] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- N. Ramanathan
- Materials Chemistry & Metal Fuel Cycle Group, Homi Bhabha National Institute, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India
| | - Shubhra Sarkar
- Materials Chemistry & Metal Fuel Cycle Group, Homi Bhabha National Institute, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India
| | - K. Sundararajan
- Materials Chemistry & Metal Fuel Cycle Group, Homi Bhabha National Institute, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India
| | - Aditi Chandrasekar
- Materials Chemistry & Metal Fuel Cycle Group, Homi Bhabha National Institute, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India
| | - K. Sankaran
- Materials Chemistry & Metal Fuel Cycle Group, Homi Bhabha National Institute, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India
| | - A. Suresh
- Materials Chemistry & Metal Fuel Cycle Group, Homi Bhabha National Institute, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India
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Maji S, Kumar S, Sundararajan K, Sankaran K. A novel luminescence method for the estimation of uranyl ions using trimesic acid‑cadmium complex. Microchem J 2018. [DOI: 10.1016/j.microc.2018.04.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Murugan V, Sankaran K. Bacterial Lipid Modification of ICP11 and a New ELISA System Applicable for WSSV Infection Detection. Mar Biotechnol (NY) 2018; 20:375-384. [PMID: 29656308 DOI: 10.1007/s10126-018-9815-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [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: 01/19/2017] [Accepted: 12/08/2017] [Indexed: 06/08/2023]
Abstract
In ELISA, a popular analytical diagnostic tool, the stable non-covalent immobilization (coating) of hydrophilic proteins/peptides on to hydrophobic polystyrene surface has remained a major common challenge. Recombinant bacterial lipid modification of proteins in Escherichia coli system has been shown in this study to solve this problem owing to the hydrophobic anchorage provided by three fatty acyl groups in N-acyl-S-diacylglyceryl Cys at the N-terminus. Exploiting this first post-translational protein engineering, the most abundantly expressed white spot syndrome viral protein ICP11 was lipid-modified and tested as a new target in a new ELISA method useful to shrimp farming. The lipid served as a potent adjuvant to enhance the titer (16 times) of higher affinity antibodies where amino terminal lipoamino acid N-acyl-S-diacylglyceryl cysteine of bacterial lipoproteins induce inflammatory responses through TLR and stimulate humoral immune responses without additional adjuvant and also aided in the immobilization of even a few nanograms of ICP11. Competition between the immobilized and the free antigen from the sample provided a sensitive measure of antigen in the infected shrimp tissues. The detection limit for ICP11 protein using competitive ELISA was 250 pg and the linear range of the assay was 15-240 ng.
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Affiliation(s)
- Vidhyapriya Murugan
- Centre for Biotechnology, Anna University, Guindy, Chennai, Tamil Nadu, 600025, India
| | - Krishnan Sankaran
- Centre for Biotechnology, Anna University, Guindy, Chennai, Tamil Nadu, 600025, India.
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12
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Kumar S, Maji S, Sundararajan K, Sankaran K. Uranyl tris nitrato as a luminescent probe for trace water detection in acetonitrile. LUMINESCENCE 2018; 33:611-615. [PMID: 29356360 DOI: 10.1002/bio.3453] [Citation(s) in RCA: 6] [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: 09/06/2017] [Revised: 11/15/2017] [Accepted: 12/13/2017] [Indexed: 11/09/2022]
Abstract
Uranyl tris nitrato i.e. [UO2 (NO3 )3 ]- was formed by adding tetramethylammonium nitrate to uranyl nitrate in acetonitrile medium. The luminescence features of this complex in acetonitrile are very sensitive to water content, which could lead to the use of it as a luminescent probe for water present in acetonitrile. The luminescence intensity ratio of 507 to 467 nm peak of uranyl tris nitrato showed a linear response in the range 0-5% (v/v) water content in acetonitrile. The present method was applied for three synthetic samples of acetonitrile for water detection and the results obtained were compared using Karl Fischer titration. There was a good agreement in the values obtained by both the methods.
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Affiliation(s)
- Satendra Kumar
- Materials Chemistry Division, Materials Chemistry & Metal Fuel Cycle Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, India
| | - S Maji
- Materials Chemistry Division, Materials Chemistry & Metal Fuel Cycle Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, India
| | - K Sundararajan
- Materials Chemistry Division, Materials Chemistry & Metal Fuel Cycle Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, India.,Homi Bhabha National Institute, Indira Gandhi Centre for Atomic Research, Kalpakkam, India
| | - K Sankaran
- Materials Chemistry Division, Materials Chemistry & Metal Fuel Cycle Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, India.,Homi Bhabha National Institute, Indira Gandhi Centre for Atomic Research, Kalpakkam, India
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13
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Affiliation(s)
- N. Ramanathan
- Materials Chemistry & Metal Fuel Cycle Group, ‡Homi Bhabha National Institute, Indira Gandhi Center for Atomic Research, Kalpakkam 603102, Tamil Nadu, India
| | - K. Sankaran
- Materials Chemistry & Metal Fuel Cycle Group, ‡Homi Bhabha National Institute, Indira Gandhi Center for Atomic Research, Kalpakkam 603102, Tamil Nadu, India
| | - K. Sundararajan
- Materials Chemistry & Metal Fuel Cycle Group, ‡Homi Bhabha National Institute, Indira Gandhi Center for Atomic Research, Kalpakkam 603102, Tamil Nadu, India
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14
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Sankaran K, Hankey A. Experience information as the basis of mind: Evidence from human decision making. Prog Biophys Mol Biol 2017; 131:369-376. [PMID: 28939327 DOI: 10.1016/j.pbiomolbio.2017.09.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 09/03/2017] [Accepted: 09/12/2017] [Indexed: 11/26/2022]
Abstract
Study of product diversity by companies and corporations led to the discovery of a new statistical distribution, the (1/f) distribution, assessed according to the Herfindahl-Hirschman index. Products of human creative thinking and decision-making seem to obey the index very widely or universally. This article explores examples of its applications in business and economics as evidence for a new scientific conjecture concerning the physiological basis of Mind: that mind functions from critical instabilities in the brain physiology. Instabilities result in (1/f) distributions of physiological responses, so the two sources of (1/f) distribution present interesting parallels. Without comprehensively reviewing all Herfindahl-Hirschman index applications, many similar examples of (1/f) distributions are considered: those in numbers of divisions and subdivisions within big corporations, and numbers of corporations in industrial sectors. Evidently, this kind of distribution derives from individual and collective creative work. The paper reasons that it reveals important evidence about the conjectured basis of mind and its creative capacities. A previous Special Issue paper showed that many of the mind's properties, including self-awareness, result from critical instabilities being the loci of control of biological systems. A consequence of such instability is that when faced by several identical stimuli, the physiology offers a (1/f) distribution of responses. Studies described here showing that creative thinking produces (1/f) distributions of results may thus be considered a first round of direct evidence for the mind functioning from critical instability. Physical systems producing (1/f) distributions do not have that implication. Other cybernetic systems may behave differently.
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Affiliation(s)
- K Sankaran
- Justice K.S. Hegde Institute of Mandagement, Karnataka, India
| | - Alex Hankey
- Dept of Yoga and Physical Sciences, S-VYASA, Bangalore, Karnataka, India.
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15
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Ramanathan N, Sundararajan K, Gopi R, Sankaran K. Photooxidation of Trimethyl Phosphite in Nitrogen, Oxygen, and para-Hydrogen Matrixes at Low Temperatures. J Phys Chem A 2017; 121:2121-2131. [DOI: 10.1021/acs.jpca.6b12296] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- N. Ramanathan
- Materials
Chemistry and Metal Fuel Cycle Group and ‡Homi Bhabha National Institute, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102, India
| | - K. Sundararajan
- Materials
Chemistry and Metal Fuel Cycle Group and ‡Homi Bhabha National Institute, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102, India
| | - R. Gopi
- Materials
Chemistry and Metal Fuel Cycle Group and ‡Homi Bhabha National Institute, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102, India
| | - K. Sankaran
- Materials
Chemistry and Metal Fuel Cycle Group and ‡Homi Bhabha National Institute, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102, India
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16
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Sundararajan K, Sankaran K, Ramanathan N, Gopi R. Production and characterization of para-hydrogen gas for matrix isolation infrared spectroscopy. J Mol Struct 2016. [DOI: 10.1016/j.molstruc.2016.03.068] [Citation(s) in RCA: 10] [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] [Indexed: 12/01/2022]
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17
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Sgro M, Kobylianskii *A, Sankaran K, Tran D, Yudin M, Campbell D. Early Onset Neonatal Sepsis in Canada: 2011-2012. Paediatr Child Health 2016. [DOI: 10.1093/pch/21.supp5.e49a] [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: 11/13/2022] Open
Abstract
Abstract
BACKGROUND: Canadian and US studies suggest that the organisms responsible for early-onset neonatal sepsis (EONS) are changing, with an increase in Escherichia coli (EC) as well as antibiotic-resistant organisms. Current Canadian guidelines for prevention and treatment of EONS are based on Group B streptococcus (GBS) as the likely organism. Population-level data may inform updates to these national strategies.
OBJECTIVES: To determine the incidence, types of organisms and corresponding resistance patterns involved in EONS in Canada. To identify how the organisms are affected by maternal antibiotic prophylaxis and other factors.
DESIGN/METHODS: Cases of EONS (defined as positive blood and/or cerebrospinal fluid (CSF) culture at <7 days of age) between January 2011 and December 2012 were identified through the Canadian Paediatric Surveillance Program (CPSP). Neonates were excluded if they were asymptomatic with a positive culture likely to be a contaminant, or if the CSF culture was positive as a result of an intracranial procedure.
RESULTS: Over the 2-year period, 127 cases meeting our criteria were identified, and there were 754,849 total Canadian live births. The incidence for EONS was 0.17/1000 live births. 79.5% of cases presented within the first 24 hours of life, while 15% presented between 72 h-7 days. GBS accounted for 41.7% of cases, while EC accounted for 35.4%. Resistance was noted in 33.9% of cases overall. 55.6% of EC were resistant, with ampicillin resistance being the most common. The species of infecting organism was significantly associated with gestational age, very low birth weight, age at presentation, the mother having received GBS prophylaxis, and rupture of membranes lasting more than 18 h. GBS was most common in term and EC in preterm neonates. The overall EONS case fatality rate was 11%, with most of these being deaths from EC.
CONCLUSION: Our study suggests a lower rate of EONS than historically suggested, with differing dominant organisms based on gestational ages of the neonates. Later ages at presentation and high rates of resistance especially among EC cases further complicate the picture. We recommend a review of the Canadian prevention and treatment guidelines based on our findings.
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18
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Gayathri CH, Mayuri P, Sankaran K, Kumar AS. An electrochemical immunosensor for efficient detection of uropathogenic E. coli based on thionine dye immobilized chitosan/functionalized-MWCNT modified electrode. Biosens Bioelectron 2016; 82:71-7. [PMID: 27040944 DOI: 10.1016/j.bios.2016.03.062] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 03/15/2016] [Accepted: 03/23/2016] [Indexed: 12/17/2022]
Abstract
Uropathogenic Escherichia coli (UPEC) is the major cause of 150 million Urinary Tract Infections (UTI) reported annually world-wide. High prevalence of multi-drug-resistance makes it dangerous and difficult to cure. Therefore simple, quick and early diagnostic tools are essential for effective treatment and control. We report an electrochemical immunosensor based on thionine dye (Th) immobilized on functionalized-multiwalled carbon nanotube+chitosan composite coated on glassy carbon electrode (GCE/f-MWCNT-Chit@Th) for quick and sensitive detection of UPEC in aqueous solution. This immunosensor was constructed by sequential immobilization of UPEC, bovine serum albumin, primary antibody and Horse Radish Peroxidase (HRP) tagged secondary antibody on the surface of GCE/f-MWCNT-Chit@Th. When analyzed using 2.5mM of hydrogen peroxide reduction reaction using cyclic voltammetry in phosphate buffer, pH 7.0, the immunosensor showed excellent linearity in a range of 10(2)-10(9)cfu of UPEC mL(-1) with a current sensitivity of 7.162μA {log(cfumL(-1))}(-1). The specificity of this immunosensor was tested using other UTI and non-UTI bacteria, Staphylococcus, Klebsiella, Proteus and Shigella. The clinical applicability of the immunosensor was also successfully tested directly in UPEC spiked urine samples (simulated sample).
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Affiliation(s)
| | - Pinapeddavari Mayuri
- Environmental and Analytical Chemistry Division, School of Advanced Sciences, Vellore Institute of Technology University, Vellore 632014, Tamil Nadu, India; Nano and Bioelectrochemistry Research Laboratory, School of Advanced Sciences, Vellore Institute of Technology University, Vellore 632014, Tamil Nadu, India
| | - Krishnan Sankaran
- Centre for Biotechnology, Anna University, Guindy, Chennai 600025, Tamil Nadu, India.
| | - Annamalai Senthil Kumar
- Environmental and Analytical Chemistry Division, School of Advanced Sciences, Vellore Institute of Technology University, Vellore 632014, Tamil Nadu, India; Nano and Bioelectrochemistry Research Laboratory, School of Advanced Sciences, Vellore Institute of Technology University, Vellore 632014, Tamil Nadu, India.
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19
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Mao G, Zhao Y, Kang X, Li Z, Zhang Y, Wang X, Sun F, Sankaran K, Zhang XC. Crystal structure of E. coli lipoprotein diacylglyceryl transferase. Nat Commun 2016; 7:10198. [PMID: 26729647 PMCID: PMC4728403 DOI: 10.1038/ncomms10198] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [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: 07/02/2015] [Accepted: 11/16/2015] [Indexed: 02/07/2023] Open
Abstract
Lipoprotein biogenesis is essential for bacterial survival. Phosphatidylglycerol:prolipoprotein diacylglyceryl transferase (Lgt) is an integral membrane enzyme that catalyses the first reaction of the three-step post-translational lipid modification. Deletion of the lgt gene is lethal to most Gram-negative bacteria. Here we present the crystal structures of Escherichia coli Lgt in complex with phosphatidylglycerol and the inhibitor palmitic acid at 1.9 and 1.6 Å resolution, respectively. The structures reveal the presence of two binding sites and support the previously reported structure–function relationships of Lgt. Complementation results of lgt-knockout cells with different mutant Lgt variants revealed critical residues, including Arg143 and Arg239, that are essential for diacylglyceryl transfer. Using a GFP-based in vitro assay, we correlated the activities of Lgt with structural observations. Together, the structural and biochemical data support a mechanism whereby substrate and product, lipid-modified lipobox-containing peptide, enter and leave the enzyme laterally relative to the lipid bilayer. Bacterial lipoproteins have important biological functions, and the lipoprotien biogenesis enzyme Lgt is essential in most gram-negative bacteria. Here, the authors use structural and biochemical techniques to shed light on the function of Lgt in post-translational transacylation modification.
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Affiliation(s)
- Guotao Mao
- National Laboratory of Macromolecules, National Center of Protein Science - Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yan Zhao
- National Laboratory of Macromolecules, National Center of Protein Science - Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China.,School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Xusheng Kang
- National Laboratory of Macromolecules, National Center of Protein Science - Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
| | - Zhijie Li
- National Laboratory of Macromolecules, National Center of Protein Science - Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
| | - Yan Zhang
- National Laboratory of Macromolecules, National Center of Protein Science - Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
| | - Xianping Wang
- National Laboratory of Macromolecules, National Center of Protein Science - Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
| | - Fei Sun
- National Laboratory of Macromolecules, National Center of Protein Science - Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
| | | | - Xuejun C Zhang
- National Laboratory of Macromolecules, National Center of Protein Science - Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
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20
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Gayathri CH, Sankaran S, Shah JH, Sankaran K. Ultrasensitive and unambiguous bacterial pathogen detection through super selective interactions between multivalent supramolecular immuno-nanoparticles (SINs). RSC Adv 2016. [DOI: 10.1039/c6ra03117j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
We have developed a rapid, cost-effective, ultrasensitive and unambiguous pathogen detection technique using multivalent supramolecular interactions between immuno-nanoparticles.
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Affiliation(s)
| | | | - Juhi H. Shah
- Centre for Biotechnology
- Anna University
- Chennai
- India
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21
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Abstract
A phosphorous trichloride (PCl3)–benzene (C6H6) heterodimer was generated in a low temperature N2 matrix and was characterized using infrared spectroscopy.
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Affiliation(s)
- N. Ramanathan
- Chemistry Group
- Indira Gandhi Center for Atomic Research
- Kalpakkam – 603102
- India
| | - K. Sankaran
- Chemistry Group
- Indira Gandhi Center for Atomic Research
- Kalpakkam – 603102
- India
| | - K. Sundararajan
- Chemistry Group
- Indira Gandhi Center for Atomic Research
- Kalpakkam – 603102
- India
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Ayed M, Moore A, Shah P, Synnes A, Sankaran K, Kalapesi Z, Lee S. 54: Outcome of Infants with Necrotising Enterocolitis (NEC): The Impact of Laparotomy Versus Peritoneal Drainage on Neurodevelopment. Paediatr Child Health 2015. [DOI: 10.1093/pch/20.5.e52a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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23
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Saranya R, Aarthi R, Sankaran K. Simple and specific colorimetric detection of Staphylococcus using its volatile 2-[3-acetoxy-4,4,14-trimethylandrost-8-en-17-yl] propanoic acid in the liquid phase and head space of cultures. Appl Microbiol Biotechnol 2015; 99:4423-33. [PMID: 25900191 DOI: 10.1007/s00253-015-6573-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [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: 11/15/2014] [Revised: 03/13/2015] [Accepted: 03/24/2015] [Indexed: 11/26/2022]
Abstract
Spread of drug-resistant Staphylococcus spp. into communities pose danger demanding effective non-invasive and non-destructive tools for its early detection and surveillance. Characteristic volatile organic compounds (VOCs) produced by bacteria offer new diagnostic targets and novel approaches not exploited so far in infectious disease diagnostics. Our search for such characteristic VOC for Staphylococcus spp. led to the depiction of 2-[3-acetoxy-4,4,14-trimethylandrost-8-en-17-yl] propanoic acid (ATMAP), a moderately volatile compound detected both in the culture and headspace when the organism was grown in tryptone soya broth (TSB) medium. A simple and inexpensive colorimetric method (colour change from yellow to orange) using methyl red as the pH indicator provided an absolutely specific way for identifying Staphylococcus spp., The assay performed in liquid cultures (7-h growth in TSB) as well as in the headspace of plate cultures (grown for 10 h on TSA) was optimised in a 96-well plate and 12-well plate formats, respectively, employing a set of positive and negative strains. Only Staphylococcus spp. showed the distinct colour change from yellow to orange due to the production of the above VOC while in the case of other organisms, the reagent remained yellow. The method validated using known clinical and environmental strains (56 including Staphylococcus, Proteus, Pseudomonas, Klebsiella, Bacillus, Shigella and Escherichia coli) was found to be highly efficient showing 100% specificity and sensitivity. Such simple methods of bacterial pathogen identification are expected to form the next generation tools for the control of infectious diseases through early detection and surveillance of causative agents.
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Affiliation(s)
- Raju Saranya
- Centre for Biotechnology, Anna University, Sardar Patel road, Guindy, Chennai, 600 025, India
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24
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Ramanathan N, Brahmmananda Rao CVS, Sankaran K, Sundararajan K. Unraveling the Conformational Landscape of Triallyl Phosphate: Matrix Isolation Infrared Spectroscopy and Density Functional Theory Computations. J Phys Chem A 2015; 119:4017-31. [DOI: 10.1021/acs.jpca.5b00889] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- N. Ramanathan
- Chemistry
Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India
| | | | - K. Sankaran
- Chemistry
Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India
| | - K. Sundararajan
- Chemistry
Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India
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25
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Joshi PR, Ramanathan N, Sundararajan K, Sankaran K. Evidence for Phosphorus Bonding in Phosphorus Trichloride–Methanol Adduct: A Matrix Isolation Infrared and ab Initio Computational Study. J Phys Chem A 2015; 119:3440-51. [DOI: 10.1021/jp511156d] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Prasad Ramesh Joshi
- Chemistry
Group, Indira Gandhi Center for Atomic Research, Kalpakkam 603102, Tamil Nadu, India
| | - N. Ramanathan
- Chemistry
Group, Indira Gandhi Center for Atomic Research, Kalpakkam 603102, Tamil Nadu, India
| | - K. Sundararajan
- Chemistry
Group, Indira Gandhi Center for Atomic Research, Kalpakkam 603102, Tamil Nadu, India
| | - K. Sankaran
- Chemistry
Group, Indira Gandhi Center for Atomic Research, Kalpakkam 603102, Tamil Nadu, India
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26
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Ramanathan N, Sundararajan K, Sankaran K. Conformations of n-butyl imidazole: matrix isolation infrared and DFT studies. Spectrochim Acta A Mol Biomol Spectrosc 2015; 139:75-85. [PMID: 25554955 DOI: 10.1016/j.saa.2014.12.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 11/28/2014] [Accepted: 12/10/2014] [Indexed: 06/04/2023]
Abstract
Conformations of n-butyl imidazole (B-IMID) were studied using matrix isolation infrared spectroscopy by trapping in argon, xenon and nitrogen matrixes using an effusive nozzle source. The experimental studies were supported by DFT computations performed at the B3LYP/6-311++G(d,p) level. Computations identified nine unique minima for B-IMID, corresponding to conformers with tg(±)tt, tg(±)g(∓)t, tg(±)g(±)t, tg(±)tg(±), tg(±)tg(∓), tg(±)g(∓)g(∓), tg(±)g(±)g(±), tg(±)g(∓)g(±) and tg(±)g(±)g(∓) structures, given in order of increasing energy. Computations of the transition state structures connecting the higher energy conformers to the global minimum, tg(±)tt structure were carried out. The barriers for the conformer inter-conversion were found to be ∼2 kcal/mol. Natural Bond Orbital (NBO) analysis was performed to understand the reasons for conformational preferences in B-IMID.
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Affiliation(s)
- N Ramanathan
- Analytical Chemistry and Spectroscopy Section, Materials Chemistry Division, Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India
| | - K Sundararajan
- Analytical Chemistry and Spectroscopy Section, Materials Chemistry Division, Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India
| | - K Sankaran
- Analytical Chemistry and Spectroscopy Section, Materials Chemistry Division, Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India.
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27
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Kumar S, Maji S, Joseph M, Sankaran K. Ligand sensitized luminescence of uranyl by benzoic acid in acetonitrile medium: a new luminescent uranyl benzoate specie. Spectrochim Acta A Mol Biomol Spectrosc 2015; 138:509-516. [PMID: 25528510 DOI: 10.1016/j.saa.2014.11.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [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: 05/21/2014] [Revised: 11/18/2014] [Accepted: 11/20/2014] [Indexed: 06/04/2023]
Abstract
Benzoic acid (BA) is shown to sensitize and enhance the luminescence of uranyl ion in acetonitrile medium. Luminescence spectra and especially UV-Vis spectroscopy studies reveal the formation of tri benzoate complex of uranyl i.e. [UO2(C6H5COO)3](-) which is highly luminescent. In particular, three sharp bands at 431, 443, 461nm of absorption spectra provides evidence for tri benzoate specie of uranyl in acetonitrile medium. The luminescence lifetime of uranyl in this complex is 68μs which is much more compared to the lifetime of uncomplexed uranyl (20μs) in acetonitrile medium. In contrary to aqueous medium where uranyl benzoate forms 1:1 and 1:2 species, spectroscopic data reveal formation of 1:3 complex in acetonitrile medium. Addition of water to acetonitrile results in decrease of luminescence intensity of this specie and the luminescence features implode at 20% (v/v) of water content. For the first time, to the best of our knowledge, the existence of [UO2(C6H5COO)3](-) specie in acetonitrile is reported. Mechanism of luminescence enhancement is discussed.
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Affiliation(s)
- Satendra Kumar
- Materials Chemistry Division, Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, India
| | - S Maji
- Materials Chemistry Division, Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, India
| | - M Joseph
- Fuel Chemistry Division, Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, India
| | - K Sankaran
- Materials Chemistry Division, Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, India.
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Sankaranarayanan R, Alagumaruthanayagam A, Sankaran K. A new fluorimetric method for the detection and quantification of siderophores using Calcein Blue, with potential as a bacterial detection tool. Appl Microbiol Biotechnol 2015; 99:2339-49. [PMID: 25634020 DOI: 10.1007/s00253-015-6411-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 01/12/2015] [Accepted: 01/15/2015] [Indexed: 12/31/2022]
Abstract
The presence of microorganisms in biological fluids like urine and blood is an indication of vulnerability to infections. Iron is one of the important micronutrients required for bacterial growth. In an iron-deficit environment, bacteria release high-affinity iron-chelating compounds called siderophores which can be used as non-invasive target molecules for the detection of such pathogens. However, only limited reagents and procedures are available to detect the presence of these organic molecules. The present study aims at detecting the presence of siderophores in the iron-depleted media, exploiting the reversible quenching of Calcein Blue and iron(III) complex. The fluorescence of Calcein Blue is known to be quenched in the presence of iron(III); if a stronger chelator removes this ion from the fluorophore, the fluorescence of the fluorophore is regained. This behaviour of the fluorophore was exploited to detect and quantify siderophores down to 50 and 800 nM equivalent of standard siderophore, deferroxamine mesylate (desferal) in Dulbecco's PBS and siderophore quantification (SPQ) medium, respectively. The siderophores released by pathogens, equivalent to standard desferal, were in the range of 1.29 to 5.00 μM and those for non-pathogens were below 1.19 μM. The simple, sensitive and cost-effective method performed in a 96-well plate was able to detect and quantify iron chelators within 7-8 h of incubation.
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Maji S, Kumar S, Sankaran K. Fluorescence and co-fluorescence of Tb(3+) and Eu(3+) in acetonitrile using 2,6-pyridine dicarboxylic acid as ligand. Spectrochim Acta A Mol Biomol Spectrosc 2015; 135:405-409. [PMID: 25105262 DOI: 10.1016/j.saa.2014.07.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [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: 05/30/2014] [Revised: 07/04/2014] [Accepted: 07/15/2014] [Indexed: 06/03/2023]
Abstract
Fluorescence from Tb(3+) and Eu(3+) complexed with 2,6-pyridine dicarboxylic acid (PDA) has been studied using acetonitrile (MeCN) as solvent. The enhancement in fluorescence intensity because of non-aqueous environment provided by the MeCN is less significant, where as fluorescence enhancement of more than two orders of magnitude has been observed with the addition of La(3+); a process known as co-fluorescence in MeCN. The present study demonstrates for the first time co-fluorescence of Tb(3+) and Eu(3+) with excitation through the absorption of PDA. Intermolecular energy transfer is believed to be responsible for co-fluorescence enhancement and it becomes possible as the quenching due to water at the secondary coordination spheres of Tb(3+) and Eu(3+) is reduced when MeCN is used as solvent.
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Affiliation(s)
- S Maji
- Material Chemistry Division, Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, India.
| | - Satendra Kumar
- Material Chemistry Division, Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, India
| | - K Sankaran
- Material Chemistry Division, Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, India
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Abstract
Treatment of ADSW with culture rich inPseudomonassp. resulting benefits such as improved physico-chemical characteristics; biomass availability for energy generation; easy operation of subsequent downstream units of effluent treatment plant.
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Affiliation(s)
- K. Sankaran
- Algal Biotechnology Laboratory
- Dept. of Energy & Environment
- National Institute of Technology
- Tiruchirappalli 620 015
- India
| | - Lakshmi Pisharody
- Algal Biotechnology Laboratory
- Dept. of Energy & Environment
- National Institute of Technology
- Tiruchirappalli 620 015
- India
| | - G. Suriya Narayanan
- Algal Biotechnology Laboratory
- Dept. of Energy & Environment
- National Institute of Technology
- Tiruchirappalli 620 015
- India
| | - M. Premalatha
- Algal Biotechnology Laboratory
- Dept. of Energy & Environment
- National Institute of Technology
- Tiruchirappalli 620 015
- India
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31
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Maji S, Kumar S, Sankaran K. Estimation of Eu(3+) in bulk uranium by ligand sensitized fluorescence in dimethyl sulphoxide. Spectrochim Acta A Mol Biomol Spectrosc 2014; 133:259-264. [PMID: 24950382 DOI: 10.1016/j.saa.2014.05.057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 03/05/2014] [Accepted: 05/06/2014] [Indexed: 06/03/2023]
Abstract
Ligand sensitized fluorescence of europium ion using thenoyltrifluoroacetone (TTA) as a sensitizing ligand and dimethyl sulphoxide (DMSO) as a solvent is studied for the first time. TTA ligand enhances the fluorescence of Eu(3+) by a factor of 40000 in DMSO. Linearity is obtained for a concentration range of 0.076-7.6ng/mL of Eu(3+) with a detection limit of 7.6pg/mL. The quenching of Eu(3+)-TTA fluorescence by uranium matrix was studied in different solvents and found to be less in DMSO. Consequently, estimation of Eu(3+) in a large excess of uranium becomes a possibility without the need to separate uranium from the solution, which has been demonstrated in this paper. Satisfactory results are obtained when Eu(3+) is present at a concentration of 0.6μg/g in uranium.
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Affiliation(s)
- S Maji
- Materials Chemistry Division, Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, India.
| | - Satendra Kumar
- Materials Chemistry Division, Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, India
| | - K Sankaran
- Materials Chemistry Division, Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, India
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Praekelt U, Reissbrodt R, Kresse A, Pavankumar A, Sankaran K, James R, Jesudason M, Anandan S, Prakasam A, Balaji V, Dutta S, Dutta S, Ramamurthy T, Fischer R, Sander P, Schaumann R, Navarro A, Williams P. Monoclonal antibodies against all known variants of EspA: development of a simple diagnostic test for enteropathogenic Escherichia coli based on a key virulence factor. J Med Microbiol 2014; 63:1595-1607. [PMID: 25231626 PMCID: PMC4250835 DOI: 10.1099/jmm.0.076323-0] [Citation(s) in RCA: 2] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Enteropathogenic Escherichia coli (EPEC) are a major cause of infant diarrhoea in developing countries and a significant public health issue in industrialized countries. Currently there are no simple tests available for the diagnosis of EPEC. Serology of O-antigens is widely used routinely in many laboratories throughout the world, even though it has been known for many years to be an unreliable indicator of EPEC virulence. We have developed a simple, low-cost immunodiagnostic test based on the EspA filament, an essential virulence factor of EPEC and the related enterohaemorrhagic E. coli (EHEC). Using recombinant proteins of the five major variants of EspA as immunogens, we raised a panel of three monoclonal antibodies in mice that detects all variants of the native target in bacterial cultures. The antibodies proved suitable for application in sandwich-type assays, including ELISA and lateral flow immunoassays (LFI). Prototypes for both assays were specific for EPEC and EHEC strains when tested against a panel of control micro-organisms. We have also developed a simple, affordable culture medium, A/E medium, which optimizes expression of EspA allowing improved sensitivity of detection compared with standard Dulbecco’s modified Eagle’s medium. Together these reagents form the basis of robust, informative tests for EPEC for use especially in developing countries but also for routine screening in any clinical laboratory.
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Affiliation(s)
- Uta Praekelt
- Department of Genetics, University of Leicester, Leicester, UK
| | - Rolf Reissbrodt
- Abteilung für Infektionskrankheiten, Robert Koch Institut, Wernigerode, Germany
| | - Andreas Kresse
- Abteilung für Infektionskrankheiten, Robert Koch Institut, Wernigerode, Germany
| | | | | | - Roger James
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | | | | | | | | | - Shanta Dutta
- National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Sanjucta Dutta
- National Institute of Cholera and Enteric Diseases, Kolkata, India
| | | | | | | | - Reiner Schaumann
- Institut für Medizinische Mikrobiologie, Universität Leipzig, Leipzig, Germany
| | - Armando Navarro
- Department of Public Health, Faculty of Medicine, National Autonomous University of Mexico, Mexico City, Mexico
| | - Peter Williams
- Department of Genetics, University of Leicester, Leicester, UK
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Kumar S, Balamurali MM, Sankaran K. Bacterial lipid modification of proteins requires appropriate secretory signals even for expression - implications for biogenesis and protein engineering. Mol Membr Biol 2014; 31:183-94. [PMID: 25156679 DOI: 10.3109/09687688.2014.943819] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Sec- and Tat-mediated bacterial lipid modification of proteins are important posttranslational processes owing to their vital roles in cellular functions, membrane targeting and biotechnological applications like ELISA, biosensor, adjuvant-free vaccines, liposomal drug delivery etc. However a better understanding of the tight coupling of secretory and lipid modification machineries and the processes associated will help unravel this essential biological event and utilize it for engineering applications. Further, there is a need for a systematic and convincing investigation into membrane targeting, solubilization and ease-of-purification of engineered lipoproteins to facilitate scientists in readily applying this new protein engineering tool. Therefore, in this study, we have investigated systematically recombinant expression, translocation, solubilization and purification of three White Spot Syndrome Viral (WSSV) proteins, ICP11, VP28 and VP281. Our study shows that the lipid modification and secretion processes are tightly coupled to the extent that mismatch between folding kinetics and signal sequence of target proteins could lead to transcriptional-translational uncoupling or aborted translation. The proteins expressed as lipoproteins through Tat-pathway were targeted to the inner membrane achieving considerable enrichment. These His-tagged proteins were then purified to apparent homogeneity in detergent-free form using single-step Immobilized Metal Affinity Chromatography. This study has interesting findings in lipoprotein biogenesis enhancing the scope of this unique post-translational protein engineering tool for obtaining pure detergent-free, membrane or hydrophobic surface-associating diagnostic targets and vaccine candidates for WSSV.
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Jantzen C, Sankaran K, Lucia M, Xiang YY, Lee S. 66: Nosocomial Infection (NI) Trends in Canadian Neonatal Intensive Care Units: Association with Mortality and Morbidity. Paediatr Child Health 2014. [DOI: 10.1093/pch/19.6.e35-64] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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36
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Bodani B, Ye XY, Bodani JP, Mirea L, Sankaran K. 65: Morbidity Free Survival in Premature Neonates Born at Less than 30 Weeks Gestation in Canada Over the Last Decade. Paediatr Child Health 2014. [DOI: 10.1093/pch/19.6.e35-63] [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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37
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Sharmila S, Christiana I, Kiran P, Reddy MVR, Sankaran K, Kaliraj P. Bacterial lipid modification enhances immunoprophylaxis of filarial abundant larval transcript-2 protein in Mastomys model. Parasite Immunol 2014; 35:201-13. [PMID: 23495791 DOI: 10.1111/pim.12034] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [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: 09/10/2012] [Accepted: 02/11/2013] [Indexed: 11/29/2022]
Abstract
As in many other parasitic diseases, efficacious vaccine for lymphatic filariasis has been elusive for want of new approaches leaving billions of people either debilitated or at risk. With multiple B- and T-cell epitopes, the abundant larval transcript-2 (ALT-2) of the filarial worm, Brugia malayi, has been shown to be a promising immunoprophylactic target. To enhance its efficacy, it was lipid modified using our recently developed protein engineering tool, which then offered 30% more immunoprotection (49 vs. 79%) in Mastomys coucha model. Sustained high levels of IFN-γ (about 100 times) and high antibody titres (10-fold) elicited by lipid-modified ALT-2, as compared to the native form, indicated the maintenance of Th1/Th2 balance that is impaired in filariasis. Thus, this study provides the basis for developing efficacious vaccines for filariasis and other parasitic diseases by exploiting bacterial lipid modification.
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Affiliation(s)
- S Sharmila
- Centre for Biotechnology, Anna University, Chennai, Tamilnadu, India
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Hemavathy RV, Sankaran K, Vadanasundari V, Rangabhashiyam S. IN SITU SEPARATION OF ETHANOL WITH AQUEOUS TWO-PHASE SYSTEM AND ASSESSMENT OF KLa FOR YEAST GROWTH IN BATCH CULTIVATION. Prep Biochem Biotechnol 2014; 44:633-44. [DOI: 10.1080/10826068.2013.844709] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Abstract
OBJECTIVE To examine rates, trends, predictive risk factors, and outcomes associated with pneumothorax in neonates. STUDY DESIGN Retrospective analyses were used to estimate rates and assess trends in pneumothorax among early preterm (GA <32 weeks), moderate-late preterm (GA 32-36), and term (GA ≥37 weeks) neonates admitted to neonatal intensive care units (NICUs) participating in the Canadian Neonatal Network™ from 2005 to 2011. For each GA group, multivariable logistic regression models were derived to predict pneumothorax using risk factors with known clinical relevance. Additional logistic regression analyses assessed associations between pneumothorax and mortality, bronchopulmonary dysplasia, and intraventricular hemorrhage. RESULTS The study included 71,237 neonates; of them 16,985 (24%) early preterm, 27,709 (39%) moderate-late preterm, and 26,543 (37%) term neonates. The overall rate of pneumothorax by GA was bimodal with estimates of 4.0%, 2.6%, and 6.7% respectively. No significant temporal trends were detected. Risk factors for pneumothorax included: a) for the overall lpopulation- Score for Neonatal Acute Physiology, version II >20, surfactant use, and respiratory distress syndrome; b) for early preterm infants-chorioamnionitis; c) for moderate-late preterm infants-higher birth weight, male sex, rupture of membranes >24 hours, and outborn status; and d) for term infants- male sex, outborn status, and meconium aspiration in term neonates. In early preterm neonates, pneumothorax was associated with mortality, bronchopulmonary dysplasia, severe intraventricular hemorrhage, and prolonged NICU stay. CONCLUSIONS Pneumothorax rates were higher among term and early preterm neonates admitted to the NICU. Predictors of pneumothorax varied between GA groups. Pneumothorax-associated mortality and morbidity were significantly greater in early preterm infants.
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Affiliation(s)
- H Hanh Duong
- Department of Pediatrics, University of Saskatchewan, Saskatoon, SK, Canada
| | - L Mirea
- Dalla Lana School of Public Health, University of Toronto, Toronto, Canada Maternal-Infant Care (MiCare) Research Centre, Department of Paediatrics, Mount Sinai Hospital, Toronto, ON, Canada
| | - P S Shah
- Dalla Lana School of Public Health, University of Toronto, Toronto, Canada Maternal-Infant Care (MiCare) Research Centre, Department of Paediatrics, Mount Sinai Hospital, Toronto, ON, Canada Department of Pediatrics, University of Toronto, ON, Canada
| | - J Yang
- Maternal-Infant Care (MiCare) Research Centre, Department of Paediatrics, Mount Sinai Hospital, Toronto, ON, Canada
| | - S K Lee
- Maternal-Infant Care (MiCare) Research Centre, Department of Paediatrics, Mount Sinai Hospital, Toronto, ON, Canada Department of Pediatrics, University of Toronto, ON, Canada
| | - K Sankaran
- Department of Pediatrics, University of Saskatchewan, Saskatoon, SK, Canada
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Olsen CM, Pemula AK, Braaen S, Sankaran K, Rimstad E. Salmonid alphavirus replicon is functional in fish, mammalian and insect cells and in vivo in shrimps (Litopenaeus vannamei). Vaccine 2013; 31:5672-9. [DOI: 10.1016/j.vaccine.2013.09.058] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 09/18/2013] [Accepted: 09/24/2013] [Indexed: 10/26/2022]
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41
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Chiang SY, Fang YS, Bahou M, Sankaran K. Experiments and Calculations on Photoionization and Dissociative Photoionization of CH2CO. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.200400103] [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: 11/10/2022]
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42
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Banerjee S, Sankaran K. First ever isolation of bacterial prolipoprotein diacylglyceryl transferase in single step from Lactococcus lactis. Protein Expr Purif 2013; 87:120-8. [DOI: 10.1016/j.pep.2012.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 11/05/2012] [Accepted: 11/06/2012] [Indexed: 10/27/2022]
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Alagumaruthanayagam A, Sankaran K. High-Throughput Fluorescence-Based Early Antibiogram Determination Using ClinicalEscherichia coliIsolates as Case Study. Microb Drug Resist 2012; 18:586-96. [DOI: 10.1089/mdr.2011.0238] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Shah PS, Sankaran K, Aziz K, Allen AC, Seshia M, Ohlsson A, Lee SK. Outcomes of preterm infants <29 weeks gestation over 10-year period in Canada: a cause for concern? J Perinatol 2012; 32:132-8. [PMID: 21593814 DOI: 10.1038/jp.2011.68] [Citation(s) in RCA: 121] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To compare risk-adjusted changes in outcomes of preterm infants <29 weeks gestation born in 1996 to 1997 with those born in 2006 to 2007. STUDY DESIGN Observational retrospective comparison of data from 15 units that participated in the Canadian Neonatal Network during 1996 to 1997 and 2006 to 2007 was performed. Rates of mortality and common neonatal morbidities were compared after adjustment for confounders. RESULT Data on 1897 infants in 1996 to 1997 and 1866 infants in 2006 to 2007 were analyzed. A higher proportion of patients in the later cohort received antenatal steroids and had lower acuity of illness on admission. Unadjusted analyses revealed reduction in mortality (unadjusted odds ratio (UAOR): 0.83, 95% confidence interval (CI): 0.63, 0.98), severe retinopathy (UAOR: 0.68, 95% CI: 0.50 to 0.92), but increase in bronchopulmonary dysplasia (UAOR: 1.61, 95% CI: 1.39 to 1.86) and patent ductus arteriosus (UAOR: 1.22, 95% CI: 1.07 to 1.39). Adjusted analyses revealed increases in the later cohort for bronchopulmonary dysplasia (adjusted odds ratio (AOR): 1.88, 95% CI: 1.60 to 2.20) and severe neurological injury (AOR: 1.49, 95% CI: 1.22 to 1.80). However, the ascertainment methods for neurological findings and ductus arteriosus differed between the two time periods. CONCLUSION Improvements in prenatal care has resulted in improvement in the quality of care, as reflected by reduced severity of illness and mortality. However, after adjustment of prenatal factors, no improvement in any of the outcomes was observed and on the contrary bronchopulmonary dysplasia increased. There is need for identification and application of postnatal strategies to improve outcomes of extreme preterm infants.
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Affiliation(s)
- P S Shah
- Division of Neonatology, Department of Paediatrics, University of Toronto, Toronto, ON, Canada.
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Abstract
To compare the effect of small for gestational age (SGA) on mortality, major morbidity and resource utilization among singleton very preterm infants (<33 weeks gestation) admitted to neonatal intensive care units (NICUs) across Canada. Infants admitted to participating NICUs from 2003 to 2008 were divided into SGA (defined as birth weight <10th percentile for gestational age and sex) and non-small gestational age (non-SGA) groups. The risk-adjusted effects of SGA on neonatal outcomes and resource utilization were examined using multivariable analyses. SGA infants (n = 1249 from a cohort of 11,909) had a higher odds of mortality (adjusted odds ratio [AOR] 2.46; 95% confidence interval [CI], 1.93-3.14), necrotizing enterocolitis (AOR 1.57; 95% CI, 1.22-2.03), bronchopulmonary dysplasia (AOR 1.78; 95% CI, 1.48-2.13), and severe retinopathy of prematurity (AOR 2.34; 95% CI, 1.71-3.19). These infants also had lower odds of survival free of major morbidity (AOR 0.50; 95% CI, 0.43-0.58) and respiratory distress syndrome (AOR 0.79; 95% CI, 0.68-0.93). In addition, SGA infants had a more prolonged stay in the NICU, and longer use of ventilation continuous positive airway pressure, and supplemental oxygen (p < 0.01 for all). SGA infants had a higher risk of mortality, major morbidities, and higher resource utilization compared with non-SGA infants.
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Affiliation(s)
- Xiangming Qiu
- Department of Paediatrics, University of Toronto, Ontario, Canada.
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Sundaram S, Banerjee S, Sankaran K. The first nonradioactive fluorescence assay for phosphatidylglycerol:prolipoprotein diacylglyceryl transferase that initiates bacterial lipoprotein biosynthesis. Anal Biochem 2012; 423:163-70. [PMID: 22342619 DOI: 10.1016/j.ab.2012.01.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 01/17/2012] [Accepted: 01/19/2012] [Indexed: 10/14/2022]
Abstract
The unique and physiologically vital bacterial enzyme, prolipoprotein diacylglyceryl transferase (Lgt), which catalyzes the committed first step in the posttranslational transfer of diacylglyceryl group from phosphatidylglycerol to the prospective N-terminal cysteine of prolipoproteins, remains to be characterized for want of a simpler but equally sensitive nonradioactive assay. We, for the first time, report a coupled enzymatic fluorescence assay for Lgt using the de novo synthetic peptide substrate MKATKSAVGSTLAGCSSHHHHHH. The assay is based on the conversion of the by-product, glycerol-1-phosphate, to dihydroxyacetone using an alkaline phosphatase-glycerol dehydrogenase combination and estimating the fluorescence of the coupled reduction of resazurin to resorufin. The minimum amount of glycerol-1-phosphate, and hence the modified peptide, detected by this method is approximately 20pmol, thereby making this assay a promising alternative to the radioactive assays. The assay is rapid, more convenient, less laborious, and suitable for purification and characterization of Lgt.
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Shah PS, Sankaran K, Aziz K, Allen A, Seshia MMK, Ohlsson A, Lee S. Comparison Of Outcomes Amoung Infants Admitted to Nicus in Canada During 2006–2007 and 1996–1997. Paediatr Child Health 2010. [DOI: 10.1093/pch/15.suppl_a.9aa] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Lodha A, Yee WH, Sankaran K, Seshia MMK, Lee SK, Shah PS. Increased Risk of Bronchopulmonary Dysplasia in Preterm Small for Gestational Age Infants Born at ≤32 Weeks Gestation in Canada: A Multicentre Study. Paediatr Child Health 2010. [DOI: 10.1093/pch/15.suppl_a.7aa] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Shruthi H, Anand P, Murugan V, Sankaran K. Twin arginine translocase pathway and fast-folding lipoprotein biosynthesis in E. coli: interesting implications and applications. Mol Biosyst 2010; 6:999-1007. [PMID: 20485744 DOI: 10.1039/b916510j] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Bacterial lipoproteins, an important class of membrane proteins, are generally thought to be translocated in an unfolded state by the well-studied Sec machinery, whereas the role of TAT, meant for folded proteins, is hardly investigated. Using appropriately engineered fast-folding Enhanced Green Fluorescence Protein (EGFP), as a model, here we show that TAT is essential for not only translocating fast-folding lipoprotein but also its lipid modification. EGFP was lipid-modified and targeted to the outer membrane's outer surface with a prototypical TAT signal sequence containing lipobox but not with the lipoprotein or TAT signal sequence. Justifiably signal sequences of many substrate-binding and co-factor-containing lipoproteins contained both TAT-box and lipobox (Shruthi et al., submitted). Cytoplasmic accumulation of unmodified precursors of engineered EGFP in a tatC mutant implicated this TAT-box-recognizing component in lipid-modification. Similar observations reported earlier with Sec components and murein lipoprotein led us to propose that the translocation-competent and translocase-associated (Sec or TAT) precursor form is prerequisite to initiation of lipid-modification in vivo. The above missing links between translocation and lipid modification machineries in vivo is important to our understanding of bacterial lipoprotein biosynthesis and its utility as a protein engineering tool for potent applications in synthetic biology and nanobiotechnology like display, arrays on bacterial surfaces, vaccines and biosensors.
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Affiliation(s)
- Hamsanathan Shruthi
- Centre for Biotechnology, Anna University, Chennai-600025, Tamil Nadu, India.
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Tan B, Bodani J, Zhu T, Janzen B, Bodani R, Rajakumar D, Kurji A, Sharma A, McConnell A, Sankaran K. Children Hospitalized with Respiratory Syncytial Virus (Rsv) Infection in Saskatchewan Pediatric Tertiary Care Centers, 2002–05. Paediatr Child Health 2009. [DOI: 10.1093/pch/14.suppl_a.28ab] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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