Identification and characterization of type III polyketide synthase genes from culturable endophytes of ethnomedicinal plants

Manoharan, Gomathi,Sairam, Thiagarajan,Thangamani, Rajesh,Ramakrishnan, Dhivya,K.Tiwari, Manish,Lee, Jung-Kul,Marimuthu, Jeya IPC Science and Technology Press 2019 Enzyme and microbial technology Vol.131 No.-

<P><B>Abstract</B></P> <P>Endophytic fungi provide benefits to host plants by producing a diverse class of secondary metabolites (natural products). Arrays of polyketide natural products are synthesized by specific classes of polyketide synthases (PKS I, II and III) in host organisms. In the present study, we attempt to screen and identify type III PKSs in culturable fungal endophytes isolated from the ethno medicinal plants including <I>Arbus precatorius</I>, <I>Bacopa monnieri,Citrus aurantifolia</I> and <I>Datura metel</I> to detect the genetic potential of endophytic fungi in producing bioactive compounds. A total of seventeen endophytic fungal strains belonging to eight genera were identified using fungal morphology and rDNA-ITS phylogenetic analyses. A CODEHOP-PCR based strategy was followed to design degenerate primers for the screening of type III PKS genes from fungal endophytes. We had successfully amplified partial PKS genes from eight endophytes. The amplified PKS sequences showed 60–99% identity to already characterized/putative PKS genes. From the partial sequence of FiPKS from <I>Fusarium incarnatum</I> BMER1, a full-length gene was amplified, cloned and characterized. FiPKScDNA was cloned and expressed in <I>E. coli</I> Lemo21 (DE3) and the purified protein was shown to produce pyrones and resorcinols using acyl-CoA thioesters as substrates. FiPKS showed the highest catalytic efficiency of 7.6 × 10<SUP>4</SUP> s<SUP>−1</SUP> M<SUP>-1</SUP> with stearoyl CoA as a starter unit. This study reports the identification and characterization of type III PKS from endophytes of medicinal plants by CODEHOP PCR.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A CODEHOP PCR based screening method was employed for type III polyketide synthase gene identification in fungal endophytes. </LI> <LI> By this approach, partial type III PKS genes from eight fungal endophytes were amplified and sequenced. </LI> <LI> FiPKS gene from Fusarium incarnatum BMER1, an endophyte of Bacopa monnieri was cloned and functionally characterized. </LI> <LI> FiPKS produced pyrones and resorcinols with the highest catalytic efficiency of 7.6 x 104 s-1 M-1towards stearoyl CoA. </LI> </UL> </P>

Demonstration of Impact of STATCOM on Loss of Excitation Protection Through Real Time Hardware in-Loop Simulation

Manoharan Kiruthiga,Raguru Pandu Kumudini Devi,Periasamy Somasundaram 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.4

This paper demonstrates the impact of Static Synchronous Compensator (STATCOM) on generator loss of excitation protection. Presence of Static Synchronous Compensator (STATCOM) in transmission line aff ects the reach/operating time of generator loss of excitation protection relay depending upon the loading conditions. In this context hardware in the loop simulation by using real time digital simulator (RT-Lab), linear power amplifi er and generator protection relay (MiCom P343) is performed to analyze the impact of Static Synchronous Compensator (STATCOM) on reach of loss of excitation protection relay. The hardware in the loop simulation is performed for total loss of excitation and partial loss of excitation. The obtained result clearly demonstrates that there is a delay in operating time of relay in the presence of Static Synchronous Compensator (STATCOM). The delay in operating time aff ects the coordination between loss of excitation protection, generator under excitation limiter and steady state stability limit

A Flyback-Assisted Single-Sourced Photovoltaic Power Conditioning System Using an Asymmetric Cascaded Multilevel Inverter

Manoharan, Mohana Sundar,Ahmed, Ashraf,Park, Joung-Hu The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.6

This paper proposes a power conditioning system (PCS) for distributed photovoltaic (PV) applications using an asymmetric cascaded multilevel inverter with a single PV source. One of the main disadvantages of the cascaded multilevel inverters in PV systems is the requirement of multiple isolated DC sources. Using multiple PV strings leads to a compromise in either the voltage balance of individual H-bridge cells or the maximum power point tracking (MPPT) operation due to localized variations in atmospheric conditions. The proposed PCS uses a single PV source with a flyback DC-DC converter to facilitate a reduction of the required DC sources and to maintain the voltage balance during MPPT operation. The flyback converter is used to provide input for low-voltage H-bridge cells which processes only 20% of the total power. This helps to minimize the losses occurring in the proposed PCS. Furthermore, transient analyses and controller design for the proposed PCS in both the stand-alone mode and the grid-connection mode are presented. The feasibility of the proposed PCS and its control scheme have been tested using a 1kW hardware prototype and the obtained results are presented.

Inhibitory effects of the essential oils α-longipinene and linalool on biofilm formation and hyphal growth of Candida albicans

Manoharan, Ranjith Kumar,Lee, Jin-Hyung,Kim, Yong-Guy,Kim, Soon-Il,Lee, Jintae HARWOOD ACADEMIC PUBLISHERS 2017 BIOFOULING -CHUR- Vol.33 No.2

Saffron Reduction of 7,12-Dimethylbenz[a]anthracene-induced Hamster Buccal Pouch Carcinogenesis

Manoharan, Shanmugam,Wani, Shamsul Afaq,Vasudevan, Krishnamoorthy,Manimaran, Asokan,Prabhakar, Murugaraj Manoj,Karthikeyan, Sekar,Rajasekaran, Duraisamy Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.2

Our aim was to investigate the chemopreventive potential of saffron in DMBA-induced hamster buccal pouch carcinogenesis. Assessment was by monitoring the percentage of tumor bearing hamsters, tumor size as well as the status of detoxification agents, lipid peroxidation and antioxidants. Oral squamous cell carcinomas were induced in the buccal pouch of Syrian golden hamsters by painting them with 0.5% DMBA in liquid paraffin three times a week for 14 weeks. We observed 100% oral tumor formation with severe histopathological abnormalities in all the hamsters treated with DMBA alone, activities of phase I and phase II detoxification enzymes, lipid peroxidation and antioxidants being significantly altered. Though oral administration of saffron completely prevented the formation of tumors, we noticed severe hyperplasia and dysplasia in hamsters treated with DMBA, suggesting that tumors might eventually develop. Oral administration of saffron return detoxification enzymes, lipid peroxidation and antioxidants to normal ranges. The chemopreventive potential of saffron thus is likely due to antioxidant properties and modulating effects on detoxification in favour of the excretion of carcinogenic metabolites during DMBA-induced hamster buccal pouch carcinogenesis.

Power Conditioning for a Small-Scale PV System with Charge-Balancing Integrated Micro-Inverter

Manoharan, Mohana Sundar,Ahmed, Ashraf,Seo, Jung-Won,Park, Joung-Hu The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.5

The photovoltaic (PV) power conditioning system for small-scale applications has gained significant interest in the past few decades. However, the standalone mode of operation has been rarely approached. This paper presents a two-stage multi-level micro-inverter topology that considers the different operation modes. A multi-output flyback converter provides both the DC-Link voltage balancing for the multi-level inverter side and maximum power point tracking control in grid connection mode in the PV stage. A modified H-bridge multi-level inverter topology is included for the AC output stage. The multi-level inverter lowers the total harmonic distortion and overall ratings of the power semiconductor switches. The proposed micro-inverter topology can help to decrease the size and cost of the PV system. Transient analysis and controller design of this micro-inverter have been proposed for stand-alone and grid-connected modes. Finally, the system performance was verified using a 120 W hardware prototype.

Efficacy of 7‐benzyloxyindole and other halogenated indoles to inhibit <i>Candida albicans</i> biofilm and hyphal formation

Manoharan, Ranjith Kumar,Lee, Jin‐,Hyung,Lee, Jintae John Wiley and Sons Inc. 2018 Microbial biotechnology Vol.11 No.6

<P><B>Summary</B></P><P>Certain pathogenic bacteria and yeast form biofilms on biotic and abiotic surfaces including medical devices and implants. Hence, the development of antibiofilm coating materials becomes relevant. The virulence of those colonizing pathogens can be reduced by inhibiting biofilm formation rather than killing pathogens using excessive amounts of antimicrobials, which is touted as one of the main reasons for the development of drug resistance. <I>Candida albicans</I> is an opportunistic fungal pathogen, and the transition of yeast cells to hyphal cells is believed to be a crucial virulence factor. Previous studies have shown that indole and its derivatives possess antivirulence properties against various bacterial pathogens. In this study, we used various indole derivatives to investigate biofilm‐inhibiting activity against <I>C. albicans</I>. Our study revealed that 7‐benzyloxyindole, 4‐fluoroindole and 5‐iodoindole effectively inhibited biofilm formation compared to the antifungal agent fluconazole. Particularly, 7‐benzyloxyindole at 0.02 mM (4.5 μg ml<SUP>−1</SUP>) significantly reduced <I>C. albicans</I> biofilm formation, but had no effect on planktonic cells, and this finding was confirmed by a 2,3‐bis‐(2‐methoxy‐4‐nitro‐5‐sulfophenyl)‐2H‐tetrazolium‐5‐carboxanilide (XTT) assay and three‐dimensional confocal laser scanning microscopy. Scanning electron microscopy analyses revealed that 7‐benzyloxyindole effectively inhibited hyphal formation, which explains biofilm inhibition. Transcriptomic analysis showed that 7‐benzyloxyindole downregulated the expressions of several hypha/biofilm‐related genes (<I>ALS3</I>,<I>ECE1</I>,<I>HWP1</I> and <I>RBT1</I>). A <I>C. albicans</I>‐infected <I>Caenorhabditis elegans</I> model system was used to confirm the antivirulence efficacy of 7‐benzyloxyindole.</P>

Dual Roles of Serine-Threonine Kinase Receptor-Associated Protein (STRAP) in Redox-Sensitive Signaling Pathways Related to Cancer Development

Manoharan, Ravi,Seong, Hyun-A,Ha, Hyunjung Hindawi 2018 Oxidative medicine and cellular longevity Vol.2018 No.-

<P>Serine-threonine kinase receptor-associated protein (STRAP) is a transforming growth factor <I>β</I> (TGF-<I>β</I>) receptor-interacting protein that has been implicated in both cell proliferation and cell death in response to various stresses. However, the precise roles of STRAP in these cellular processes are still unclear. The mechanisms by which STRAP controls both cell proliferation and cell death are now beginning to be unraveled. In addition to its biological roles, this review also focuses on the dual functions of STRAP in cancers displaying redox dysregulation, where it can behave as a tumor suppressor or an oncogene (i.e., it can either inhibit or promote tumor formation), depending on the cellular context. Further studies are needed to define the functions of STRAP and the redox-sensitive intracellular signaling pathways that enhance either cell proliferation or cell death in human cancer tissues, which may help in the development of effective treatments for cancer.</P>

Expression of salicylic acid-related genes in <i>Brassica oleracea</i> var. <i>capitata</i> during <i>Plasmodiophora brassicae</i> infection

Manoharan, Ranjith Kumar,Shanmugam, Ashokraj,Hwang, Indeok,Park, Jong-In,Nou, Ill-Sup,Scoles, G.J. Canadian Science Publishing 2016 Genome Vol.59 No.6

<P> Brassica oleracea var. capitata (cabbage) is an important vegetable crop in Asian countries such as Korea, China, and Japan. Cabbage production is severely affected by clubroot disease caused by the soil-borne plant pathogen Plasmodiophora brassicae. During clubroot development, methyl salicylate (MeSA) is biosynthesized from salicylic acid (SA) by methyltransferase. In addition, methyl salicylate esterase (MES) plays a major role in the conversion of MeSA back into free SA. The interrelationship between MES and methytransferases during clubroot development has not been fully explored. To begin to examine these relationships, we investigated the expression of MES genes in disease-susceptible and disease-resistant plants during clubroot development. We identified three MES-encoding genes potentially involved in the defense against pathogen attack. We found that SS1 was upregulated in both the leaves and roots of B. oleracea during P. brassicae infection. These results support the conclusion that SA biosynthesis is suppressed during pathogen infection in resistant plants. We also characterized the expression of a B. oleracea BSMT gene, which appears to be involved in glycosylation rather than MeSA biosynthesis. Our results provide insight into the functions and interactions of genes for MES and methyltransferase during infection. Taken together, our findings indicate that MES genes are important candidates for use to control clubroot diseases. </P>

Descriptive Epidemiology of Primary Brain and CNS Tumors in Delhi, 2003-2007

Manoharan, N.,Julka, P.K.,Rath, G.K. Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.2

The Delhi Population Based Cancer Registry data during the period 2003-2007 were used to describe the epidemiology of primary malignant brain and central nervous system tumors in Delhi. A total of 1989 brain and CNS tumors cases in 1291 males and 698 females were registered during the period 1st January 2003 to 31st December 2007. The age adjusted (world population) incidence rates were 3.9 per 100,000 for males and 2.4 per 100,000 for females. Gliomas were the most frequently reported histology both in males (26.6%) and females (23.2%). A male predominance in incidence was observed for all histological classifications. The rates in Delhi are low compared to the incidences reported from developed countries.