In vivo and in vitro effect of Acacia nilotica seed proteinase inhibitors on Helicoverpa armigera (Hübner) larvae

• Published in: Journal of biosciences 2012-06, Vol.37 (2), p.269-276
• Main Authors: Ramesh Babu, S, Subrahmanyam, B, Srinivasan, Santha, I M
• Format: Article
• Language: English
• Subjects: Acacia - chemistry; Acacia - metabolism; Acacia nilotica; Administration, Oral; Ammonia; Ammonium; Ammonium sulfate; Animals; Biomedical and Life Sciences; Biomedicine; Cell Biology; Chromatography; Chymotrypsin; Diet; Diets; Digestive tract; electrophoresis; experimental diets; Gastrointestinal Tract - drug effects; Gastrointestinal Tract - enzymology; Genetic engineering; Helicoverpa armigera; Hydrogen-Ion Concentration; Inhibitor drugs; Kinetics; Larva; Larvae; Life Sciences; Microbiology; Midgut; Molecular Weight; Moths - drug effects; Moths - enzymology; pH effects; Plant Extracts - chemistry; Plant Extracts - isolation & purification; Plant Extracts - pharmacology; Plant Proteins - administration & dosage; Plant Proteins - chemistry; Plant Proteins - isolation & purification; Plant Proteins - metabolism; Plant Sciences; Precipitation; Protein folding; protein purification; Protein Stability; Proteinase inhibitors; Proteolysis; Seeds; Seeds - chemistry; Serine Proteinase Inhibitors - chemistry; Serine Proteinase Inhibitors - isolation & purification; Serine Proteinase Inhibitors - pharmacology; transgenic plants; Trypsin; Trypsin - chemistry; Zoology
• ISSN: 0250-5991; 0973-7138
• DOI: 10.1007/s12038-012-9204-8

Acacia nilotica proteinase inhibitor (AnPI) was isolated by ammonium sulphate precipitation followed by chromatography on DEAE-Sephadex A-25 and resulted in a purification of 10.68-fold with a 19.5% yield. Electrophoretic analysis of purified AnPI protein resolved into a single band with molecular weight of approximately 18.6 + 1.00 kDa. AnPI had high stability at different pH values (2.0 to 10.0) except at pH 5.0 and are thermolabile beyond 80°C for 10 min. AnPI exhibited effective against total proteolytic activity and trypsin-like activity, but did not show any inhibitory effect on chymotrypsin activity of midgut of Helicoverpa armigera. The inhibition kinetics studies against H. armigera gut trypsin are of non-competitive type. AnPI had low affinity for H. armigera gut trypsin when compared to SBTI. The partially purified and purified PI proteins-incorporated test diets showed significant reduction in mean larval and pupal weight of H. armigera. The results provide important clues in designing strategies by using the proteinase inhibitors (PIs) from the A. nilotica that can be expressed in genetically engineered plants to confer resistance to H. armigera.