Yeast Cyclophilins Prevent Cold Denaturation of Proteins

Mahendran Chinnamara Naicker,김양희,이경희,임하나 대한화학회 2016 Bulletin of the Korean Chemical Society Vol.37 No.3

Freezing environments are one of the major challenges faced by many organisms, including Saccharomyces cerevisiae. Exposure to low temperatures reduces protein folding rates and induces the cold denaturation of proteins, necessitating aid from chaperones. In a previous study, we identified 19 chaperone genes, the deletion of which makes the host more vulnerable to freeze-and-thaw treatments. Among those, peptidyl–prolyl cis–trans isomerases (PPIases) were the most frequently identified. At low temperatures, peptidyl–prolyl isomerization is a rate-limiting step in protein folding, and folding intermediates, which are prone to protein aggregation, tend to accumulate. To characterize their mode of function, the identified PPIases were overexpressed in Escherichia coli. Not only did they increase the survival of E. coli during freeze-and-thaw treatment at –20 °C, but they also protected β-galactosidase against freeze-induced protein denaturation. Purified Cpr1p facilitated the refolding of a slow-folding substrate protein in vitro. These results suggest that the identified PPIases enhance cold survival of cells by preventing cold-induced protein denaturation and promoting protein folding.

Multi-objective Unbalanced Distribution Network Reconfiguration through Hybrid Heuristic Algorithm

Mahendran, G.,Sathiskumar, M.,Thiruvenkadam, S.,Lakshminarasimman, L. The Korean Institute of Electrical Engineers 2013 Journal of Electrical Engineering & Technology Vol.8 No.2

Electrical power distribution systems are critical links between the utility and customer. In general, power distribution systems have unbalanced feeders due to the unbalanced loading. The devices that dependent on balanced three phase supply are affected by the unbalanced feeders. This necessitates the balancing of feeders. The main objective of reconfiguration is to balance the loads among the phases subject to constraints such as load flow equations, capacity and voltage constraints and to reduce the real power loss, while subject to a radial network structure in which all loads must be energized. Therefore, the distribution system reconfiguration problem has been viewed as multi-objective problem. In this paper, the hybrid heuristic algorithm has been used for reconfiguration, which is the combination of fuzzy and greedy algorithms. The purpose of the introduction of greedy is to refrain the searching for the period of phase balancing. The incorporation of fuzzy helps to take up more objectives amid phase balancing in the searching. The effectiveness of the proposed method is demonstrated through modified IEEE 33 bus and modified IEEE 125 bus radial distribution system.

Identification of Chaperones in Freeze Tolerance in Saccharomyces cerevisiae

Mahendran Chinnamara Naicker,조이슬,임하나 한국미생물학회 2012 The journal of microbiology Vol.50 No.5

Exposure to low temperatures reduces protein folding rates and induces the cold denaturation of proteins. Considering the roles played by chaperones in facilitating protein folding and preventing protein aggregation, chaperones must exist that confer tolerance to cold stress. Here, yeast strains lacking individual chaperones were screened for reduced freezing tolerance. In total, 19 of 82 chaperone-deleted strains tested were more sensitive to freeze-thaw treatment than wild-type cells. The reintroduction of the respective chaperone genes into the deletion mutants recovered the freeze tolerance. The freeze sensitivity of the chaperone-knockout strains was also retained in the presence of 20% glycerol.

Molecular Phylogeny of Silk Producing Insects Based on Internal Transcribed Spacer DNA1

Mahendran, Botlagunta,Ghosh, Sudip K.,Kundu, Subhas C. Korean Society for Biochemistry and Molecular Biol 2006 Journal of biochemistry and molecular biology Vol.39 No.5

Silk moths are the best studied silk secreting insects and belong to the families Bombycidae and Saturniidae. The phylogenetic relationship between eleven silk producing insects was analyzed using the complete DNA sequence of the internal transcribed spacer DNA 1 locus. The PCR amplification and sequence analysis showed variation in length ranging from 138 bp (Antheraea polyphemus) to 911 bp (Hyalopora cecropia). Microsatellite sequences were found and was be used to distinguish Saturniidae and Bombycidae members. The nucleotide sequences were aligned manually and used for construction of phylogenetic trees based on Maximum parsimony and Maximum likelihood methods. The topology in both the approaches yielded a similar tree that supports the ancestral position of the Antheraea assama.

Mechanical and metallurgical properties of diffusion bonded AA2024 Al and AZ31B Mg

Mahendran, G.,Balasubramanian, V.,Senthilvelan, T. Techno-Press 2012 Advances in materials research Vol.1 No.2

In the present study, diffusion bonding was carried out between AZ31B magnesium and AA2024 aluminium in the temperature range of $405^{\circ}C$ to $475^{\circ}C$ for 15 min to 85 min and 5MPa to 20 MPa uniaxial loads was applied. Interface quality of the joints was assessed by microhardness and shear testing. Also, the bonding interfaces were analyzed by means of optical microscopy, scanning electron microscopy, energy dispersive spectrometer and XRD. The maximum bonding and shear strength was obtained at $440^{\circ}C$, 12 MPa and 70 min. The maximum hardness values were obtained from the area next to the interface in magnesium side of the joint. The hardness values were found to decrease with increasing distance from the interface in magnesium side while it remained constant in aluminium side. It was seen that the diffusion transition zone near the interface consists of various phases of $MgAl_2O_4$, $Mg_2SiO_4$ and $Al_2SiO_5$.

Local buckling behaviour of steel plate elements supported by a plastic foam material

Mahendran, M.,Jeevaharan, M. Techno-Press 1999 Structural Engineering and Mechanics, An Int'l Jou Vol.7 No.5

Sandwich panels comprising steel facings and a polystyrene foam core are increasingly used as roof and wall claddings in buildings in Australia. When they are subjected to loads causing bending and/or axial compression, the steel plate elements of their profiled facing are susceptible to local buckling. However, when compared to panels with no foam core, they demonstrate significantly improved local buckling behaviour because they are supported by foam. In order to quantify such improvements and to validate the use of available design buckling stress formulae, an investigation using finite element analyses and laboratory experiments was carried out on steel plates that are commonly used in Australia of varying yield stress and thickness supported by a polystyrene foam core. This paper presents the details of this investigation, the buckling results and their comparison with available design buckling formulae.

Multi-objective Unbalanced Distribution Network Reconfiguration through Hybrid Heuristic Algorithm

G. Mahendran,M. Sathiskumar,S. Thiruvenkadam,L. Lakshminarasimman 대한전기학회 2013 Journal of Electrical Engineering & Technology Vol.8 No.2

Electrical power distribution systems are critical links between the utility and customer. In general, power distribution systems have unbalanced feeders due to the unbalanced loading. The devices that dependent on balanced three phase supply are affected by the unbalanced feeders. This necessitates the balancing of feeders. The main objective of reconfiguration is to balance the loads among the phases subject to constraints such as load flow equations, capacity and voltage constraints and to reduce the real power loss, while subject to a radial network structure in which all loads must be energized. Therefore, the distribution system reconfiguration problem has been viewed as multiobjective problem. In this paper, the hybrid heuristic algorithm has been used for reconfiguration, which is the combination of fuzzy and greedy algorithms. The purpose of the introduction of greedy is to refrain the searching for the period of phase balancing. The incorporation of fuzzy helps to take up more objectives amid phase balancing in the searching. The effectiveness of the proposed method is demonstrated through modified IEEE 33 bus and modified IEEE 125 bus radial distribution system.

BiPO4/Fe-metal organic framework composite: A promising photocatalyst toward the abatement of tetracycline hydrochloride, Indigo Carmine and reduction of 4-nitrophenol

Nithya Mahendran,Keerthi Praveen 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.100 No.-

A novel BiPO4/NH2-MIL-53(Fe) composite was synthesized through solvothermal method. Photocatalyticperformances of the synthesized composites were evaluated by removal of tetracycline hydrochloride(TCH) and Indigo Carmine (IC) pollutants under visible light irradiation. It was revealed that BiPO4/NH2-MIL-53(Fe) composites displayed better photocatalytic performance than pure BiPO4 and NH2-MIL-53(Fe) catalysts individually. Among the composites optimal ratio is 3:1 of BiPO4/NH2-MIL-53(Fe) (BPM-1)exhibits the highest photocatalytic activity which is 80% and 94% removal of TCH and IC within 2 h. Theenhancement in the photocatalytic activity is because of the more efficient visible light absorption andeffective charge separation that makes the photo degradation process easier. The electrochemicalimpedance results of BPM-1 substantiated the reduction in there combination of electron–hole pairs incomparison to the bare materials. The composite also showed better catalytic reduction efficiency for 4-nitrophenol reduction. Recyclability test validates the better photochemical stability and reusability ofBPM-1. This work will provide a new path to design and fabricate composite photocatalysts based on themetal organic framework for various pollutants degradation and reduction applications.

Fullerenol-Based Electroactive Artificial Muscles Utilizing Biocompatible Polyetherimide

Rajagopalan, Mahendran,Oh, Il-Kwon American Chemical Society 2011 ACS NANO Vol.5 No.3

<P>Two essential functional requirements for electroactive artificial muscles, which can be used for biomedical active devices, are biocompatibility and sufficient range of motion. Fullerenol nanoparticles and their derivatives have been validated as potential candidates to be used for nanobiomaterials and biomedical applications because of their excellent proton conductivity, hydrophilicity, and biocompatibility. We developed fullerenol-based electroactive artificial muscles utilizing biocompatible polyetherimide. By using a solvent recasting method, present ionic networking membranes have been successfully synthesized with homogeneous dispersion of polyhydroxylated fullerene (PHF) nanoparticles into a sulfonated polyetherimide (SPEI) matrix. In comparison with pure SPEI membranes, the PHF−SPEI nanocomposite membranes show much higher water uptake and proton conductivity, which are both essential characteristics for high-performance ionic polymer actuators. The developed PHF−SPEI actuator shows over three times larger motion ranges and two times higher blocking forces than the pure SPEI actuator. The excellent biocompatibility of PHF and SPEI makes these actuators promising candidate materials for biomedical devices such as active stents and catheters.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2011/ancac3.2011.5.issue-3/nn103521g/production/images/medium/nn-2010-03521g_0016.gif'></P>

Molecular Phylogeny of Silk Producing Insects Based on Internal Transcribed Spacer DNA1

( Botlagunta Mahendran ),( Sudip K. Ghosh ),( Subhas C. Kundu ) 생화학분자생물학회 2006 BMB Reports Vol.39 No.5