The structure of a Bacteroides thetaiotaomicron carbohydrate-binding module provides new insight into the recognition of complex pectic polysaccharides by the human microbiome

Funding Information: We thank Prof. Carlos Fontes and Dr Joana Bras (NZYTech, Portugal) for their assistance in obtaining the initial BT0996-C clone. We are grateful to Prof Ten Feizi, Dr Yan Liu and Dr Lisete Silva from the Glycosciences Laboratory (Imperial College London, UK) for their support and assistance on robotic microarray printing. This work was supported by the FCT - Fundação para a Ciência e a Tecnologia, I.P., through the DL-57/2016 Program Contract (BP). This work is financed by national funds from FCT - Fundação para a Ciência e a Tecnologia, I.P., in the scope of the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy - i4HB. The authors acknowledge the European Synchrotron Radiation Facility (Grenoble, France) and ALBA (Barcelona, Spain) for access to beamlines ID30B and BL-13 XALOC, respectively. Publisher Copyright: © 2022The Bacteroides thetaiotaomicron has developed a consortium of enzymes capable of overcoming steric constraints and degrading, in a sequential manner, the complex rhamnogalacturonan II (RG-II) polysaccharide. BT0996 protein acts in the initial stages of the RG-II depolymerisation, where its two catalytic modules remove the terminal monosaccharides from RG-II side chains A and B. BT0996 is modular and has three putative carbohydrate-binding modules (CBMs) for which the roles in the RG-II degradation are unknown. Here, we present the characterisation of the module at the C-terminal domain, which we designated BT0996-C. The high-resolution structure obtained by X-ray crystallography reveals that the protein displays a typical β-sandwich fold with structural similarity to CBMs assigned to families 6 and 35. The distinctive features are: 1) the presence of several charged residues at the BT0996-C surface creating a large, broad positive lysine-rich patch that encompasses the putative binding site; and 2) the absence of the highly conserved binding-site signatures observed in CBMs from families 6 and 35, such as region A tryptophan and region C asparagine. These findings hint at a binding mode of BT0996-C not yet observed in its homologues. In line with this, carbohydrate microarrays and microscale thermophoresis show the ability of BT0996-C to bind α1-4-linked polygalacturonic acid, and that electrostatic interactions are essential for the recognition of the anionic polysaccharide. The results support the hypothesis that BT0996-C may have evolved to potentiate the action of BT0996 catalytic modules on the complex structure of RG-II by binding to the polygalacturonic acid backbone sequence.publishersversionpublishe

High mobility group box 1 levels in large vessel vasculitis are not associated with disease activity but are influenced by age and statins

Introduction: Takayasu arteritis (TA) and giant cell arteritis (GCA) are large vessel vasculitides (LVV) that usually present as granulomatous inflammation in arterial walls. High mobility group box 1 (HMGB1) is a nuclear protein that acts as an alarmin when released by dying or activated cells. This study aims to evaluate whether serum HMGB1 can be used as a biomarker in LVV. Methods: Twenty-nine consecutive TA patients with 29 healthy controls (HC) were evaluated in a cross-sectional study. Eighteen consecutive GCA patients with 16 HC were evaluated at the onset of disease and some of them during follow-up. Serum HMGB1 levels were measured by enzyme-linked immunosorbent assay. Results: In GCA patients at disease onset mean serum HMGB1 levels did not differ from HC (5.74 +/- 4.19 ng/ml vs. 4.17 +/- 3.14 ng/ml; p = 0.230). No differences in HMGB1 levels were found between GCA patients with and without polymyalgia rheumatica (p = 0.167), ischemic manifestations (p = 0.873), systemic manifestations (p = 0.474) or relapsing disease (p = 0.608). During follow-up, no significant fluctuations on serum HMGB1 levels were observed from baseline to 3 months (n = 13) (p = 0.075), 12 months (n = 6) (p = 0.093) and at the first relapse (n = 4) (p = 0.202). Serum HMGB1 levels did not differ between TA patients and HC [1.19 (0.45-2.10) ng/ml vs. 1.46 (0.89-3.34) ng/ml; p = 0.181] and no difference was found between TA patients with active disease and in remission [1.31 (0.63-2.16) ng/ml vs. 0.75 (0.39-2.05) ng/ml; p = 0.281]. HMGB1 levels were significantly lower in 16 TA patients on statins compared with 13 patients without statins [0.59 (0.29-1.46) ng/ml vs. 1.93 (0.88-3.34) ng/ml; p = 0.019]. Age was independently associated with higher HMGB1 levels regardless of LVV or control status. Conclusions: Patients with TA and GCA present similar serum HMGB1 levels compared with HC. Serum HMGB1 is not useful to discriminate between active disease and remission. In TA, use of statins was associated with lower HMGB1 levels. HMGB1 is not a biomarker for LVV

Guia metodológico para avaliação de ambientes de ensino pós covid : estudo de caso FAU/UnB

Muitos ambientes de ensino tiveram suas rotinas alteradas com a chegada da pandemia do novo Coronavírus. No contexto da Universidade de Brasília (UnB), que está desde de março de 2020 desenvolvendo atividades remotas, também estão sendo desenvolvidas uma série de atividades de planejamento visando à reocupação responsável do Campus. Neste sentido, este presente documento tem por objetivo informar todas as atividades desenvolvidas pelo subcomitê de infraestrutura e serviços da Faculdade de Arquitetura e Urbanismo (FAU) da UnB, no âmbito do Comitê de Coordenação de Acompanhamento das Ações de Recuperação (CCAR). Este estudo está delimitado para a realidade de uso e ocupação da FAU/UnB, que fica localizada na ala norte do Instituto Central de Ciências – ICC, um dos edifícios mais emblemáticos de toda a Universidade. Destaca-se que há limitação temporal no referencial bibliográfico e técnico consultados e produzidos para o desenvolvimento deste estudo, os quais foram a base para a metodologia utilizada neste guia. A proposta do guia é oferecer uma possibilidade metodológica que auxilie gestores educacionais em reavaliarem os seus espaços para possibilitar uma ocupação dos ambientes de forma segura, responsável e com salubridade

Soil corrosion of the AISI1020 steel buried near electrical power transmission line towers

Soil corrosion of carbon steel samples buried up to hundred days close to a high voltage power transmission line tower was examined by weight loss vs. time. A higher weight loss was observed if the samples were electrically connected to the tower than if they were not. This was attributed to the influence of alternating current (AC) signals induced in the soil by the transmission line. This field study showed for the first time the influence of the AC power line on the buried structure of the tower, while other studies so far were focused only on AC corrosion of cathodically protected coated pipelines, running parallel to the transmission line. An improved method was used to measure weight loss by descaling in Clark solution. The new method substitutes discontinuous measurements, proposed in the ASTM-G1-90 standard, by in situ measurements of the weight loss during descaling, using a computer controlled microbalance