Sambandam Ravikumar
Catholic University of Daegu
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Publication
Featured researches published by Sambandam Ravikumar.
Journal of Biotechnology | 2013
Irisappan Ganesh; Sambandam Ravikumar; Seung-Hwan Lee; Si Jae Park; Soon Ho Hong
DcuS/DcuR two component system (TCS) was firstly employed for the expression of the gfp gene under the dcuB gene promoter in aerobic condition to develop high throughput screening system able to screen microorganisms producing high amount of fumarate. However, the DcuS/DcuR TCS could not produce a signal strong enough to mediate the expression of the gfp gene responding fumarate concentration. Thus, DcuS/DucR TCS was engineered by recruiting the EnvZ/OmpR system, the most-studied TCS in E. coli. A chimeric DcuS/EnvZ (DcuSZ) TCS was constructed by fusing the sensor histidine kinase of DcuS with the cytoplasmic catalytic domain of EnvZ, in which the expression of the gfp gene or the ompC gene was mediated by the ompC gene promoter through the cognate response regulator, OmpR. The output signals produced by the chimeric DcuSZ TCS were enough to detect fumarate concentration quantatively, in which the expressions of the gfp gene and the ompC gene were proportional to the fumarate concentration in the medium. Moreover, principal component analysis of C4-dicarboxylates showed that DcuSZ chimera was highly specific to fumarate but could also respond to other C4-dicarboxylates, which strongly suggests that TCS-based high throughput screening system able to screen microorganisms producing target chemicals can be developed.
Journal of Photochemistry and Photobiology B-biology | 2014
T.V.M. Sreekanth; Sambandam Ravikumar; In-Yong Eom
Silver nanoparticles (AgNPs) with a mean particle size of ∼ 16.7 nm were synthesized using an eco-friendly reducing material, aqueous Nelumbo nucifera root extract. Rapid reduction resulted in the formation of polydispersed nanoparticles. The formation of AgNPs was characterized by surface plasmon resonance, which was determined by ultraviolet-visible (UV-Vis) spectroscopy (band at 412 nm), Fourier transform infrared spectroscopy, scanning electron microscopy-energy dispersive X-ray spectroscopy, transmission electron microscopy and X-ray diffraction. The interaction of the green synthesized AgNPs with Bovine Serum Albumin (BSA) at various temperatures was investigated. Fluorescence quenching, synchronous and resonance light scattering spectroscopy along with UV-Vis absorption studies revealed the efficient binding between BSA and the AgNPs. In addition, the AgNPs exhibited moderate antioxidant and cytotoxicity activities against HeLa cell lines.
Bioprocess and Biosystems Engineering | 2015
Irisappan Ganesh; Sambandam Ravikumar; Ik-Keun Yoo; Soon Ho Hong
In an attempt to develop a high-throughput screening system for screening microorganisms which produce high amounts of malate, a MalKZ chimeric HK-based biosensor was constructed. Considering the sequence similarity among Escherichia coli (E. coli) MalK with Bacillus subtilis MalK and E. coli DcuS, the putative sensor domain of MalK was fused with the catalytic domain of EnvZ. The chimeric MalK/EnvZ TCS induced the ompC promoter through the cognate response regulator, OmpR, in response to extracellular malate. Real-time quantitative PCR and GFP fluorescence studies showed increased ompC gene expression and GFP fluorescence as malate concentration increased. By using this strategy, various chimeric TCS-based bacteria biosensors can be constructed, which may be used for the development of biochemical-producing recombinant microorganisms.
Korean Journal of Chemical Engineering | 2015
Sambandam Ravikumar; Irisappan Ganesh; Murali kannan Maruthamuthu; Soon Ho Hong
In an attempt to create an acidic amino acid-sensing Escherichia coli, a chimeric sensor kinase (SK)-based biosensor was constructed using Pseudomonas putida AauS. AauS is a sensor kinase that ultimately controls expression of the aau gene through its cognate response regulator AauR, and is found only in P. putida KT2440. The AauZ chimera SK was constructed by integration of the sensing domain of AauS with the catalytic domain of EnvZ to control the expression of the ompC gene in response to acidic amino acids. Real-time quantitative PCR and GFP fluorescence studies showed increased ompC gene expression and GFP fluorescence as the concentration of acidic amino acids increased. These data suggest that AauS-based recombinant E. coli can be used as a bacterial biosensor of acidic amino acids. By employing the chimeric SK strategy, various bacteria biosensors for use in the development of biochemical-producing recombinant microorganisms can be constructed.
Korean Journal of Chemical Engineering | 2013
Irisappan Ganesh; Sambandam Ravikumar; Si Jae Park; Seung Hwan Lee; Soon Ho Hong
The malate-pyruvate conversion pathway is catalyzed by two malic enzyme isomers, MaeA and MaeB. qRT-PCR was carried out under malate and pyruvate supplemented conditions to understand the dynamics of maeA and maeB gene expression. maeA expression was elevated by malate, and maeB expression was inhibited by levels of both malate and pyruvate higher than 0.1 mM. Green fluorescent protein (GFP) reporter plasmids were also constructed by integration of the maeA/maeB promoter with the gfp gene. We showed that maeA driven GFP expression was positively and negatively correlated with extracellular malate and pyruvate induction. In contrast, no significant changes in maeB driven GFP expression were observed under both malate and pyruvate supplemented conditions.
Applied Biochemistry and Biotechnology | 2014
Pandurangan Muthuraman; Sambandam Ravikumar; Veerappan Muthuviveganandavel; Jongpil Kim
Biotechnology Letters | 2015
Murali kannan Maruthamuthu; Irisappan Ganesh; Sambandam Ravikumar; Soon Ho Hong
Bioprocess and Biosystems Engineering | 2015
Murali kannan Maruthamuthu; Saravanan Prabhu Nadarajan; Irisappan Ganesh; Sambandam Ravikumar; Hyungdon Yun; Ik-Keun Yoo; Soon Ho Hong
Cytotechnology | 2014
Muthuraman Pandurangan; Sambandam Ravikumar
In Vitro Cellular & Developmental Biology – Animal | 2014
Sambandam Ravikumar; Pandurangan Muthuraman