Duplications and Functional Convergence of Intestinal Carbohydrate-Digesting Enzymes

Vertebrate diets and digestive physiologies vary tremendously. Although the contribution of ecological and behavioral features to such diversity is well documented, the roles and identities of individual intestinal enzymes shaping digestive traits remain largely unexplored. Here, we show that the sucrase-isomaltase (SI)/maltase-glucoamylase (MGAM) dual enzyme system long assumed to be the conserved disaccharide and starch digestion framework in all vertebrates is absent in many lineages. Our analyses indicate that independent duplications of an ancestral SI gave rise to the mammalian-specific MGAM, as well as to other duplicates in fish and birds. Strikingly, the duplicated avian enzyme exhibits similar activities to MGAM, revealing an unexpected case of functional convergence. Our results highlight digestive enzyme variation as a key uncharacterized component of dietary diversity in vertebrates.

Study of liver enzyme variation in children with dengue fever

Background: Dengue fever continues to be one of the major public health problems in large parts of the world, with an estimated 50 million dengue infections occurring annually. Liver enzyme variation is commonly seen in patients with dengue fever. This study was undertaken to assess the pattern of liver enzyme variation in children with dengue fever and to correlate it with the severity of this disease.Methods: Observational, descriptive hospital-based study involving 100 children who were serologically positive for dengue fever. The cases were classified as Mild, Moderate and Severe Dengue based on National Guidelines of clinical management of Dengue fever, 2015 and severity was assessed in each category. The study assessed the variability of liver enzymes in these children.Results: Aspartate Aminotransferase (AST) was elevated in 56 cases whereas Alanine Aminotransferase (ALT) was elevated in 44 cases. The elevation in liver enzymes in mild cases was 52%, moderate cases was 75% and severe cases was 100%. In cases presenting on day 1 of fever, enzymes were elevated in 0%, on day 2 in 20%, on day 3 in 38%, on day 4 in 51%, on day 5 in 90% and on day 6 in 88%.Conclusions: Liver Enzyme (AST and ALT) elevation in Dengue is a common feature. AST elevation was more common than ALT. Highest elevation in liver enzymes were observed on 5th and 6th day of fever. Liver enzyme elevation was more commonly seen in moderate and severe cases.