A non-peptide probe for detecting chymotrypsin activity based on protection-deprotection strategy in living systems

Chymotrypsin (CHT) plays a vital role in the metabolism of organisms, and affects the cell proliferation and apoptosis. Abnormal level of CHT will lead to a variety of diseases, such...

Purification and characterization of protease inhibitors from rice bean (Vigna umbellata) and their efficacy against Spodoptera litura (Fabricius) gut proteinases

A protease inhibitor from rice bean was isolated and purified to assess its potential against gut proteases of Spodoptera litura, a devastating pest of several economically important crops globally. The purified inhibitor showed a single band protein on SDS-PAGE corresponding to molecular weight of 24.0 kDa. The inhibitor was purified to near homogeneity with 181.55 fold purification and final yield of 29.18 per cent. The inhibitory potential of purified rice bean trypsin protease inhibitor on larvae of Spodoptera gut proteases was studied which showed maximum azocaseinolytic (1.93U), trypsin (0.66U) and chymotrypsin activity (0.37 U) in second larval instar which gradually decreased upto late fifth larval instar stage. Inhibitory assay revealed that rice bean trypsin inhibitors were strong inhibitor of Spodoptera litura and inhibited more than 80 per cent for trypsin and around 69 per cent for chymotrypsin activity. To further determine the efficacy of rice bean protease inhibitors, feeding assays were conducted by adding rice bean flour in larval artificial diet. High mortality rate was observed in Spodoptera litura larvae after 72 hrs when rice bean was given as sole diet (100% rice bean composition). The results obtained from present study provide important clues in designing strategies for sustainable use of rice bean protease inhibitors in developing insect-tolerant transgenic plants.

Encapsulated blends of essential oils and organic acids improved performance, intestinal morphology, cecal microflora, and jejunal enzyme activity of broilers

This study investigated effects of encapsulated blends of essential oils (EO) and organic acids (OA) on performance, intestinal morphology, cecal microflora, and jejunal mucosal enzyme activity and secretory IgA (s-IgA) level of broilers. Three hundred one-day-old male broilers were divided into 5 treatments with 5 replicates each. Control group received basal diet. Three additional groups received basal diets supplemented with 150, 200, or 250 mg/kg encapsulated blends of EO and OA. Antibiotic group received basal diet supplemented with 30 mg/kg bacitracin zinc. On days 21 and 70 of trial, 2 broilers from each replicate were weighed, and then blood, duodenum, jejunum, ileum, and cecum samples were collected. Results showed that broilers fed blends of EO and OA had greater average daily gain (ADG) (linear, P = 0.043) and gain-to-feed ratio (G : F) (linear, P = 0.052) at day 21 compared to broilers fed the control diet. Blends of EO and OA reduced cecal Escherichia coli and Salmonella level of 21- and 70-day-old broilers (linear, P < 0.01). Jejunum villus height-to-crypt depth ratio (VCR) of 21-day-old broilers was elevated by blends of EO and OA (linear, P = 0.041) compared to control. Blends of EO and OA promoted chymotrypsin activity at day 21 (quadratic, P = 0.014), jejunal mucosal s-IgA content at day 70 (linear, P = 0.012), α-amylase activity at day 70 (quadratic, P = 0.043), and chymotrypsin activity at day 70 (quadratic, P = 0.037). Compared to control, antibiotic group increased ADG at day 21 (P = 0.039), decreased cecal Salmonella level at day 21 (P = 0.018), enhanced jejunum VCR at day 21 (P = 0.049), and elevated jejunal mucosal s-IgA content at day 21 (P = 0.016). It can be stated that EO and OA blends enhanced performance, increased jejunal s-IgA level and enzyme activity, improved intestinal morphology, and balanced intestinal microflora of broilers.