Entomology Research Institute

Chennai, India

Entomology Research Institute

Chennai, India
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Baskar K.,Entomology Research Institute | Baskar K.,Vivekananda College | Ignacimuthu S.,Entomology Research Institute
Chemosphere | Year: 2012

Ononitol monohydrate isolated from the ethyl acetate extract of Cassia tora L. using column chromatography was evaluated for its antifeedant, larvicidal and growth inhibitory activities against Helicoverpa armigera and Spodoptera litura at different concentrations of 125, 250, 500 and 1000. ppm. Leaf disc no-choice method was used for the bioassay. The compound showed significant antifeedant, larvicidal and pupicidal activities against H. armigera and S. litura. The compound also prolonged the larval-pupal duration of the insect at all the tested concentrations. The activities were concentration dependent for both the insects. Ononitol could be used as an agent to prepare botanical new pesticidal formulations. © 2012 Elsevier Ltd.

Subash-Babu P.,King Saud University | Ignacimuthu S.,Entomology Research Institute | Alshatwi A.A.,King Saud University
Chemico-biological interactions | Year: 2015

Nymphaea stellata (Willd.) has been used in traditional medicine for centuries to treat several illnesses, including diabetes. However, scientific evidence supporting its mechanism of action is lacking. Here, we showed that an N. stellata flower chloroform extract (NSFCExt) has significant plasma glucose lowering ability. Furthermore, an active compound was identified and purified by column chromatography, and the structure of this compound, nymphayol, was determined by X-ray crystallographic analysis. Nymphayol was tested for its effects on insulin secretion by RIN-5F cells cultured in low or high glucose medium; we found that nymphayol treatment improved glucose-stimulated insulin secretion in vitro. Additionally, insulin sensitization and glucose uptake were increased in L6 myotubes. Nymphayol was administered to type 2 diabetic male Wistar rats at several doses (5, 10 or 20 mg/kg/day) for 45 days. After nymphayol administration, the plasma glucose concentration was significantly (p⩽0.05) lower (60.33%) than in control diabetic rats, and the plasma insulin level increased in a dose-dependent manner. In addition, the cellular insulin response was analyzed in type 2 diabetic rats; oral administration of nymphayol increased IRS1 phosphorylation and GLUT4 protein expression in liver and muscle. Nymphayol significantly (p⩽0.05) restored the levels of HbA1c, hepatic glycogen and hepatic glucose-metabolizing enzyme (hexokinase, glucose-6-phosphate dehydrogenase, glucose-6-phosphatase, fructose-1, 6-bisphosphatase, glycogen synthase and glycogen phosphorylase) activity in diabetic rats. The administration of glibenclamide, a reference drug (600 μg/kg), also produced a significant (p⩽0.05) reduction in blood glucose in STZ-nicotinamide induced diabetic rats. The results suggest that nymphayol may be a useful therapy for diabetes because it stimulates insulin secretion and promotes glucose absorption. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Maheswaran R.,Entomology Research Institute | Ignacimuthu S.,Entomology Research Institute
Parasitology research | Year: 2014

The present study aimed to evaluate the essential oil and an isolated compound from the leaves of Polygonum hydropiper L. against dengue vector mosquito Aedes albopictus L. The plant material was macerated and steam distilled using clavenger apparatus for oil extraction. The essential oil was tested at different concentrations of 100, 50, 25, 12.5 and 6.25 ppm concentrations against the larvae of Ae. albopictus. The isolated compound was tested for larvicidal, ovicidal, repellent, oviposition deterrent and adulticidal activities at 10, 5, 2.5, 1.25 and 0.625 ppm concentrations. The essential oil exhibited LC₅₀ values of 194.63 and 199.65 and confertifolin exhibited LC₅₀ values of 2.02 and 3.16 against the second and fourth instar larvae of Ae. albopictus, respectively. The ovicidal activity of 100% on 0- to 6-h-old eggs, repellent activity of 320.6 min, oviposition deterrent activity of 98.51% and adulticidal activity of 100% at 10 ppm concentration of confertifolin were recorded. No mortality of was observed in negative control. To the best of our knowledge, this is the first report on the potential mosquitocidal activities of confertifolin against Ae. albopictus.

Ignacimuthu S.,Entomology Research Institute | Ceasar S.A.,Entomology Research Institute
Journal of Biosciences | Year: 2012

Finger millet plants conferring resistance to leaf blast disease have been developed by inserting a rice chitinase (chi11) gene through Agrobacterium-mediated transformation. Plasmid pHyg-Chi.11 harbouring the rice chitinase gene under the control of maize ubiquitin promoter was introduced into finger millet using Agrobacterium strain LBA4404 (pSB1). Transformed plants were selected and regenerated on hygromycin-supplemented medium. Transient expression of transgene was confirmed by GUS histochemical staining. The incorporation of rice chitinase gene in R 0 and R 1 progenies was confirmed by PCR and Southern blot analyses. Expression of chitinase gene in finger millet was confirmed by Western blot analysis with a barley chitinase antibody. A leaf blast assay was also performed by challenging the transgenic plants with spores of Pyricularia grisea. The frequency of transient expression was 16.3% to 19.3%. Stable frequency was 3.5% to 3.9%. Southern blot analysis confirmed the integration of 3.1 kb chitinase gene. Western blot analysis detected the presence of 35 kDa chitinase enzyme. Chitinase activity ranged from 19.4 to 24.8. In segregation analysis, the transgenic R 1 lines produced three resistant and one sensitive for hygromycin, confirming the normal Mendelian pattern of transgene segregation. Transgenic plants showed high level of resistance to leaf blast disease compared to control plants. This is the first study reporting the introduction of rice chitinase gene into finger millet for leaf blast resistance. © 2012 Indian Academy of Sciences.

Ceasar S.A.,Entomology Research Institute | Ignacimuthu S.,Entomology Research Institute
Renewable and Sustainable Energy Reviews | Year: 2011

Jatropha has drawn the attention of researchers in recent years due to its emergence as a highly suitable feedstock plant for Biodiesel production. Efforts have been made to improve the Jatropha plant material and Biodiesel production. Tissue culture, transformation and molecular marker based studies were conducted to improve the plant material. Biochemical engineering were undertaken to improve both the process and product of Biodiesel from Jatropha. Various approaches were taken up to improve the oil extraction process from seeds, enhance the quality and quantity of Biodiesel and analyze the engine performance of Jatropha Biodiesel. Most of the studies have been carried out in recent years due to the growing interest in energy security and global warming posed by fossil fuels. In this review we give details of various biotechnological and biochemical engineering efforts related to Jatropha and Biodiesel. © 2011 Elsevier Ltd. All rights reserved.

Ceasar S.A.,Entomology Research Institute | Ignacimuthu S.,Entomology Research Institute
Plant Cell Reports | Year: 2011

A new Agrobacterium-mediated transformation system was developed for finger millet using shoot apex explants. The Agrobacterium strain LBA4404 harboring binary vector pCAMBIA1301, which contained hygromycin phosphotransferase (hptII) as selectable marker gene and β-glucuronidase (GUS) as reporter gene, was used for optimization of transformation conditions. Two finger millet genotypes, GPU 45 and CO 14, were used in this study. The optimal conditions for the Agrobacterium-mediated transformation of finger millet were found to be the co-cultivation of explants obtained on the 16th day after callus induction (DACI), exposure of explants for 30 min to agrobacterial inoculum and 3 days of co-cultivation on filter paper placed on medium supplemented with 100 μM acetosyringone (AS). Addition of 100 μM l-cysteine in the selection medium enhanced the frequency of transformation and transgenic plant recovery. Both finger millet genotypes were transformed by Agrobacterium. A frequency of 19% transient expression with 3. 8% stable transformation was achieved in genotype GPU 45 using optimal conditions. Five stably transformed plants were fully characterized by Southern blot analysis. A segregation analysis was also performed in four R 1 progenies, which showed normal Mendelian pattern of transgene segregation. The inheritance of transgenes in R 1 progenies was also confirmed by Southern blot analysis. This is the first report on Agrobacterium-mediated transformation of finger millet. This study underpins the introduction of numerous agronomically important genes into the genome of finger millet in the future. © 2011 Springer-Verlag.

Ceasar S.A.,Entomology Research Institute | Ignacimuthu S.,Entomology Research Institute
Biotechnology Letters | Year: 2012

Fungal diseases damage crop plants and affect agricultural production. Transgenic plants have been produced by inserting antifungal genes to confer resistance against fungal pathogens. Genes of fungal cell wall-degrading enzymes, such as chitinase and glucanase, are frequently used to produce fungal-resistant transgenic crop plants. In this review, we summarize the details of various transformation studies to develop fungal resistance in crop plants. © 2012 Springer Science+Business Media B.V.

Maheswaran R.,Entomology Research Institute | Ignacimuthu S.,Entomology Research Institute
Parasitology Research | Year: 2012

The objective of this study was to develop a herbal formulation to control dengue vector mosquitoes. PON-NEEM, a novel herbal formulation prepared using the oils of neem (Azadirachta indica), karanj (Pongamia glabra) and their extracts, was tested for larvicidal, ovicidal and oviposition deterrent activities against Aedes aegypti and Aedes albopictus at 1, 0.5, 0.3 and 0.1 ppm concentrations. Cent percent larvicidal and ovicidal activities were observed at 0.1 ppm in the two mosquito species under laboratory and sunlight-exposed conditions up to 12 months from the date of manufacture. Oviposition deterrent activity of 69.97% and 71.05% was observed at 1 ppm concentration of PONNEEM against A. aegypti and A. albopictus, respectively. Reduction in enzyme levels for α-esterase was 0.089±0.008 and 0.099±0.140 μg napthol produced/min/mg larval protein; for β-esterase, it was 0.004±0.009 and 0.001 ±0.028 μg napthol produced/min/mg larval protein; for glutathione S-transferase, it was 10.4814±0.23 and 11.4811±0.21 μmol/min/mg larval protein and for total protein, it was 0.177± 0.010 and 0.008±0.005 mg/individual larva in treated groups of A. aegypti and A. albopictus, respectively. The nontarget organisms such as Gambusia affinis and Diplonychus indicus were not affected. No mortality was observed in control. PONNEEM can be used effectively for the management of human vector mosquitoes. © Springer-Verlag 2012.

Sunil C.,Entomology Research Institute | Ignacimuthu S.,Entomology Research Institute
Food and Chemical Toxicology | Year: 2011

Methanol extract of Symplocos cochinchinensis S. Moore leaves was evaluated for its in vitro and in vivo antioxidant activity. The total phenolic content of the extract was 230mg of gallic acid equivalents/g extract. The extract showed very good scavenging activity on 2,2-diphenyl-picrylhydrazyl (DPPH) (IC 50 620.30±0.14μg/ml), hydroxyl (IC 50 730.21±1.05μg/ml), nitric oxide (IC 50 870.31±0.19μg/ml) radicals, as well as high reducing power. The extract also showed strong suppressive effect on lipid peroxidation. In in vivo study CCl 4 induced oxidative stress produced significant increase in SGOT, SGPT and LDH levels along with reduction in liver SOD, CAT, GSH and GPx levels. Pre-treatment of rats with the extract (250 and 500mg/kg) for 7days showed significant reduction in the levels of SGOT, SGPT and LDH compared to CCl 4 treated rats. SOD, CAT, GSH and GPx levels were increased significantly due to treatment with the extract. The activity of the extract was comparable to the standard drug, silymarin (25mg/kg). The results suggest that the leaves of S. cochinchinensis are a source of natural antioxidants. © 2011 Elsevier Ltd.

Ramachandran P.V.,Entomology Research Institute | Ignacimuthu S.,Entomology Research Institute
Applied Biochemistry and Biotechnology | Year: 2013

RNA interference (RNAi) is an evolutionary conserved gene regulation pathway that has emerged as an important discovery in the field of molecular biology. One of the important advantages of RNAi in therapy is that it brings about efficient downregulation of gene expression by targeting complementary transcripts in comparison with other antisensebased techniques. RNAi can be can be achieved by introducing chemically synthesized small interfering RNAs (siRNAs) into a cell system. A more stable knockdown effect can be brought about by the use of plasmid or viral vectors encoding the siRNA. RNAi has been used in reverse genetics to understand the function of specific genes and also as a therapeutic tool in treating human diseases. This review provides a brief insight into the therapeutic applications of RNAi against debilitating diseases. © Springer Science+Business Media New York 2013.

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