Endo-β-1, 4-glucanase (EC 220.127.116.11) activity was measured in the gut fluid of phytophagous insect Podontia quatuordecimpunctata Linnaeus (Coleoptera: Chrysomelidae) in different days of development. The eight day-old larva showed maximum activity with 1.73 U mg-1 of protein, which was confirmed by gel zymography. In zymogram, using Carboxymethyl Cellulose (CMC) as substrate, four distinct cellulolytic protein bands were detected in leaf borer gut fluids through out of its development. The optimum temperature and pH were 60°C and 5.0, respectively. This endo-β-1,4-glucanase showed maximum stability at 20-45°C with ~ 20% remaining activity. Zymography also showed complete loss of endo-β-1,4 glucanase activity at 55°C. This is the first report that the cellulolytic enzyme is produced in the gut of P. quatuordecimpunctata through the whole developmental stages, from the 1st instar to the adult, except for pupae.
Mohammad Mosleh Uddin, Md. Mahmudul Hasan Chowdhury, Suman Mojumder and Dwaipayan Sikdar, 2012. Multiple Endo-β-1,4-glucanases Present in the Gut Fluid of a Defoliating
Beetle, Podontia quatuordecimpunctata (Coleoptera: Chrysomelidae). Pakistan Journal of Biological Sciences, 15: 333-340.