Turning universal O into rare Bombay type blood.

Red blood cell antigens play critical roles in blood transfusion since donor incompatibilities can be lethal. Recipients with the rare total deficiency in H antigen, the Oh Bombay phenotype, can only be transfused with group Oh blood to avoid serious transfusion reactions. We discover FucOB from the mucin-degrading bacteria Akkermansia muciniphila as an α-1,2-fucosidase able to hydrolyze Type I, Type II, Type III and Type V H antigens to obtain the afucosylated Bombay phenotype in vitro. X-ray crystal structures of FucOB show a three-domain architecture, including a GH95 glycoside hydrolase. The structural data together with site-directed mutagenesis, enzymatic activity and computational methods provide molecular insights into substrate specificity and catalysis. Furthermore, using agglutination tests and flow cytometry-based techniques, we demonstrate the ability of FucOB to convert universal O type into rare Bombay type blood, providing exciting possibilities to facilitate transfusion in recipients/patients with Bombay phenotype.

Characterization of patients with ocular pain evaluated with ultrasound.

BACKGROUND: The cause of ocular pain in the quiet eye is challenging to diagnose. It is a common complaint in the ophthalmology clinic and there are no actual guidelines on the exams that should be ordered initially. We decided to characterize patients with eye pain and normal ophthalmological examination who underwent ocular ultrasound, their findings, and systemic work-up. METHODS: A retrospective chart review of patients who underwent ocular ultrasound due to ocular pain and no clinical findings on initial slit-lamp examination. We evaluated patient characteristics and analyzed systemic work-up results in contrast to ocular ultrasound findings. RESULTS: Two hundred and three patients with normal slit-lamp examination and ocular pain were evaluated using ocular ultrasound at Clinica Barraquer. Most of the patients were women (88.7%), and 55% were older than 50 years. Nearly all of the patients had echographic findings, 87.7% of patients showed evidence of scleral scars, from which 66.5% had signs of activity, and 42.9% had thickened extraocular muscles. In general, most patients with ocular pain had normal results on systemic work-up, but the patients who did have positive results tended to have echographic findings. CONCLUSION: Posterior inflammation is present in most patients with ocular pain in a quiet eye, and echography is an optimal tool to identify this. There is a tendency towards abnormal autoimmune test results and echographic findings. This should be considered in the initial work-up of these patients, given the importance of early diagnosis and the threat of vision loss with severe inflammation.

Mechanism of cooperative N-glycan processing by the multi-modular endoglycosidase EndoE.

Bacteria produce a remarkably diverse range of glycoside hydrolases to metabolize glycans from the environment as a primary source of nutrients, and to promote the colonization and infection of a host. Here we focus on EndoE, a multi-modular glycoside hydrolase secreted by Enterococcus faecalis, one of the leading causes of healthcare-associated infections. We provide X-ray crystal structures of EndoE, which show an architecture composed of four domains, including GH18 and GH20 glycoside hydrolases connected by two consecutive three α-helical bundles. We determine that the GH20 domain is an exo-ß-1,2-N-acetylglucosaminidase, whereas the GH18 domain is an endo-ß-1,4-N-acetylglucosaminidase that exclusively processes the central core of complex-type or high-mannose-type N-glycans. Both glycoside hydrolase domains act in a concerted manner to process diverse N-glycans on glycoproteins, including therapeutic IgG antibodies. EndoE combines two enzyme domains with distinct functions and glycan specificities to play a dual role in glycan metabolism and immune evasion.