Role of glycoside phosphorylases in mannose foraging by human gut bacteria.

To metabolize both dietary fiber constituent carbohydrates and host glycans lining the intestinal epithelium, gut bacteria produce a wide range of carbohydrate-active enzymes, of which glycoside hydrolases are the main components. In this study, we describe the ability of phosphorylases to participate in the breakdown of human N-glycans, from an analysis of the substrate specificity of UhgbMP, a mannoside phosphorylase of the GH130 protein family discovered by functional metagenomics. UhgbMP is found to phosphorolyze β-D-Manp-1,4-β-D-GlcpNAc-1,4-D-GlcpNAc and is also a highly efficient enzyme to catalyze the synthesis of this precious N-glycan core oligosaccharide by reverse phosphorolysis.

Functional metagenomics to mine the human gut microbiome for dietary fiber catabolic enzymes.

The human gut microbiome is a complex ecosystem composed mainly of uncultured bacteria. It plays an essential role in the catabolism of dietary fibers, the part of plant material in our diet that is not metabolized in the upper digestive tract, because the human genome does not encode adequate carbohydrate active enzymes (CAZymes). We describe a multi-step functionally based approach to guide the in-depth pyrosequencing of specific regions of the human gut metagenome encoding the CAZymes involved in dietary fiber breakdown.

Testicular adrenal rest tumours in salt wasting congenital adrenal hyperplasia (in vivo and in vitro studies).

We describe the case of a 20-year-old patient with salt-wasting congenital adrenal hyperplasia (CAH) related to 21-hydroxylase deficiency. Bilateral craggy testicular tumours were found, requiring histological evaluation. Prior to the surgical procedure, the patient was treated with dexamethasone (he presented cortisol deficiency) and was stimulated with ACTH.

[Inappropriate secretion of antidiuretic hormone and diabetes insipidus after surgery for pituitary adenoma].

The purpose of our study was to evaluate the incidence and risk factors of SIADH (syndrome of inappropriate antidiuretic hormone) and diabetes insipidus after pituitary adenoma surgery in patients and report follow-up data collected in our department of endocrinology. This retrospective study included 78 patients seen in the last 5 years. Possible risk factors of SIADH and diabetes insipidus were studies: patient age and gender, type of secretion, tumor volume, surgical approach, presence of postoperative pituitary failure.