ABSTRACT
The present study reports the purification of a lectin from Colocasia esculenta (L.) Schott corms and evaluation of its anti-insect potential towards Bactrocera cucurbitae (Coquilett). The lectin was found to be specific towards N-acetyl-D-lactosamine (LacNac), a disaccharide and asialofetuin, a desialylated serum glycoprotein in hemagglutination inhibition assay. Asialofetuin was used as a ligand to purify Colocasia esculenta agglutinin (CEA) by affinity chromatography. The purity of CEA was ascertained by the presence of a single band in reducing SDS-PAGE at pH 8.3. The affinity purified CEA was employed in artificial diet bioassay of second instar larvae (64-72 hr old) of the B. cucurbitae at concentrations ranging between 10-160 µg ml-1. The lectin significantly (p<0.01) decreased the percent pupation and emergence with respect to control. Effect on various enzymes was studied by employing LC50 (51.6 µg ml-1) CEA in the artificial diet bioassay of second instar larvae. All the enzymes tested namely esterases, phosphatases (acid and alkaline), superoxide dismutases, catalase and glutathione-S-transferase showed a significant (p<0.01, p<0.05) increase in their enzyme and specific activities. These results showed that CEA affected normal growth and development and presented stress to the larvae, activating their detoxification and anti-oxidant systems. Thus, the lectin seems to be a useful candidate for the control measures of B. cucurbitae under the integrated pest management (IPM) system.
ABSTRACT
Aims: The present study aimed to evaluate and ascertain the protective role of methanolic/ethanolic/water extracts of Convolvulus pluricaulis against H2O2 induced cytotoxicity in IMR32 Neuroblastoma cell line as model system and identify the factor responsible for the protective effect. Study Design: Experimental study. Place and Duration of Study: Department of Molecular Biology and Biochemistry, Guru Nanak Dev University, Amritsar & Department of Biotechnology, DAV College, Amritsar, PuCPab, between August 2010 and March 2012. Methodology: Firstly, cytotoxic dose of H2O2 and non-toxic dose of methanolic, ethanolic and water extracts of C. pluricaulis (CP-MEx, CP-EEx and CP-WEx respectively) was determined by MTT assay. Protective effect of CP-MEx, CP-EEx and CP-WEx was determined using quercetin as a positive control. The expression of IMR32 cytoskeletal marker, Neurofilament (NF-200) and stress markers, Heat shock protein (HSP70) and (glucose regulated protein 75, Grp75) Mortalin studied by immunofluorescence and RTPCR results. The level of antioxidant enzymes catalase, superoxide dismutase, glutathione peroxidase, direct scavenger of free radicals, Glutathione and lipid peroxidation were analysed by their standard procedures. Results: The results showed that quercetin, CP-MEx, CP-EEx and CP-WEx displayed cytoprotective activity in IMR32 cells. Out of tested extracts CP-MEx significantly decreased hydrogen peroxide-induced cell death. Significant decrease in NF-200, HSP70 and Mortalin expression was observed in CP-MEx+H2O2 treated cultures as compared to H2O2 treated. Catalase, superoxide dismutase, glutathione peroxidase, Glutathione levels significantly increased in Quercetin and CP-MEx treated cultures. Lipid peroxidation was significantly decreased in both Quercetin and CP-MEx treated cultures. Conclusions: The present work establishes the protective effect of CP-MEx on IMR 32 Human Neuroblastoma cell line which is as much as by quercetin. The cytoprotective effect of CP-MEx was due to induction of antioxidant machinery of the cell hence holds therapeutic value in the treatment and/or prevention of neurodegenerative disorders of oxidative stress.
ABSTRACT
Bactrocera cucurbitae (Coquillett), also known as melon fruit fly, is one of the major insect pests of cucurbits in several parts of Asia, Africa and Pacific. In the present investigation, effect of lectins from two sources i.e. Arisaema intermedium Blume and Arisaema wallichianum Hook f. (Family-Araceae) has been studied on the development of second instar larvae of melon fruit fly. The lectins were incorporated separately in artificial diet at a concentration of 10 to 160 µg ml-1 and fed adlibitum to the second instar larvae. Both the lectins were found to prolong the development period and significantly inhibited the pupation and emergence in a dose dependent manner. Total development period was found to be prolonged by 3.5 and 2.3 days in case of larvae fed on artificial diet containing A. intermedium (AIL) and A. wallichianum (AWL), respectively. LC50 values calculated on the basis of adult emergence came out to be 32.8 and 29 µg ml-1 for AIL and AWL, respectively. Both the lectins tested, were found to increase the activity of esterases as larvae proceeded from 24 to 72 hr of treatment. The activity of acid phosphatase decreased significantly in larvae reared on diet containing LC50 of AIL, while in case of AWL significant decrease was observed only at 72 hr of treatment. Alkaline phosphatase activity decreased significantly on treatment with both of these lectins. These results showed that AIL and AWL have promising anti-insect potential. So, lectin gene/s from either of these species can be cloned and subsequently can be employed to develop transgenics to control melon fruit flies specifically and insect pests in general. This approach could be used as a part of Integrated pest management (IPM) strategies.