Calcium as an inhibitor of tripsin activity in pancreatic juice of chicken

The results of studying the interaction of calcium and pancreatic enzymes in 46-week-old Hisex white chickens are presented. It is shown that intestinal absorption of calcium is accompanied by endogenous excretion of calcium with digestive juices. The effect of calcium on tryptic activity in an in vitro experiment was determined. In the experiment, different doses of calcium (5.0; 7.5; 0.5; 12.5 and 25.0 mg) were injected into the pancreatic juice of chickens, previously diluted with physiological solution 10 times. The number of repetitions in each variant of the experiment was 20 times. For the experiment, 2-aqueous calcium chloride (Chimmed, RF) was used. Trypsin activity was determined by the kinetic method. The content of calcium was determined with a Sinnowa BS-3000P biochemical analyzer (China) and a set for the determination of calcium in the blood of animals DIAKON-VET (RF). It was found that pancreatic juice of chickens contains up to 2.9 ± 0.03 mmol of calcium/l, which is comparable to the level of calcium in the blood serum of 1.99 ± 0.10 – 3.13 ± 0.20 mmol/l. The inhibiting effect of calcium on the tryptic activity was found. A five-fold increase in calcium in pancreatic juice of chickens reduces the activity of trypsin by 34.7%. According to the analysis of variance, the concentration of calcium in pancreatic juice affects tryptic activity, the reliability of the effect is confirmed by 92%. A stable negative correlation was established between calcium content in pancreatic juice and activity of trypsin r = –0.78, which is consistent with the correlation of the corresponding parameters in the blood. These findings serve as evidence that calcium together with proteases can be regarded as an element that regulates metabolic processes in chickens.

Evidence of Disturbed Gut Microbial Metabolic Activity in Pediatric Crohn’s Disease

Background Dysbiosis, that is, disturbed gut microbial balance, is well documented in Crohn’s disease (CD). We aimed at studying CD-linked dysbiosis in children by analyzing fecal microbe-associated characteristics, previously not reported in children. Methods This observational study included 28 children with active CD and healthy controls. We assessed the following three indicators of gut microbiota metabolism in the feces: the presence of tryptic activity, the conversion of cholesterol to coprostanol, and the conversion of bilirubin to urobilinogen. Results The fecal tryptic activity was significantly higher in children with active CD compared to the control group (P < 0.01). The fecal coprostanol of the CD children was close to zero and differed significantly from the controls (P < 0.001). Furthermore, the children with CD had very low fecal urobilinogen, differing significantly from the control group (P < 0.001). Conclusions The significant differences in levels of fecal bacterial metabolites in patients with active CD compared to healthy controls reflect major perturbation of gut microbial functions and have not previously been reported in children. This fits well with the prevailing concept of a dysbiotic gut microbiota in CD and may have important clinical implications by bringing the dysbiosis back into balance.

Identification and characterisation of gut proteases in the fig tree skeletoniser moth, Choreutis nemorana Hübner (Lepidoptera: Choreutidae)

The biochemical properties of proteases from the digestive system of the fig tree skeletonizer moth, Choreutis nemorana, were determined. Gut extracts of C. nemorana larvae were analysed using different specific peptide substrates and proteinase inhibitors. The optimal pH and temperature for proteolytic activities using azocasein as substrate were obtained as pH 11 and 45°C, respectively. In the case of N-benzoyl-l-arg-p-nitroanilide as substrate, the enzyme showed the maximum tryptic activity at pH 11. The kinetic parameters of trypsin-like proteases indicated that the K_m and V_max values of trypsin in the gut of C. nemorana were 0.157 ± 0.006mM and 0.188 ± 0.005 µmol/min/mgprotein. Using specific proteolytic inhibitors, the inhibitors including phenyl methane sulfonyl fluoride, N-p-tosyl-l-lys chloromethyl ketone and ethylene diamine tetraacetic acid showed the greatest inhibitory effect on total proteolytic activity. These results indicated that serine proteinases accounted for the major proteases in the gut of C. nemorana. Inhibition assays and zymogram analysis showed that only small amounts of cysteine proteases are present in the digestive system of C. nemorana.