The C-terminal domain of the MERS coronavirus M protein contains a trans -Golgi network localization signal

International audienceCoronavirus M proteins represent the major protein component of the viral envelope. They play an essential role during viral assembly by interacting with all the other structural proteins. Coronaviruses bud into the endoplasmic reticulum (ER)-Golgi intermediate compartment (ERGIC), but the mechanisms by which M proteins are transported from their site of synthesis, the ER, to the budding site remain poorly understood. Here, we investigated the intracellular trafficking of the Middle East respiratory syndrome coronavirus (MERS-CoV) M protein. Subcellular localization analyses revealed that the MERS-CoV M protein is retained intracellularly in the trans-Golgi network (TGN), and we identified two motifs in the distal part of the C-terminal domain as being important for this specific localization. We identified the first motif as a functional diacidic DxE ER export signal, since substituting Asp-211 and Glu-213 with alanine induced retention of the MERS-CoV M in the ER. The second motif, 199 KxGxYR 204 , was responsible for retaining the M protein in the TGN. Substitution of this motif resulted in MERS-CoV M leakage toward the plasma membrane. We further confirmed the role of 199 KxGxYR 204 as a TGN retention signal by using chimeras between MERS-CoV M and the M protein of infectious bronchitis virus (IBV). Our results indicated that the C-terminal domains of both proteins determine their specific localization, namely, TGN and ERGIC/cis-Golgi for MERS-M and IBV-M, respectively. Our findings indicate that MERS-CoV M protein localizes to the TGN because of the combined presence of an ER export signal and a TGN retention motif

Viruses and Type 1 Diabetes: Focus on the Enteroviruses

Pollution & threats to the environmen

GERENCIAMENTO DE RESÍDUOS SÓLIDOS DE UMA INDÚSTRIA GRÁFICA COM ENFOQUE EM PRODUÇÃO MAIS LIMPA (P+L): ESTUDO DE CASO NO ESPÍRITO SANTO

No segmento industrial gráfico, dentre os impactos ambientais causados pela geração de poluição, a geração de resíduos sólidos torna-se fator preocupante, dado a relação de sua geração com o desperdício de matérias-primas, aumento de custos de produção e reduzida eficiência no processo industrial, o que exerce influência sobre a valoração do produto final, sobre a rentabilidade econômica destes produtos e a competitividade da indústria no mercado. Desta forma, a otimização da produção industrial é fator decisivo para competitividade e permanência no mercado. A redução da geração de poluição, mitigação dos impactos ambientais e a otimização de processos, em sua forma preventiva, está ancorada na Política Nacional de Resíduos Sólidos, Lei nº 12.305/2010. O gerenciamento de resíduos sólidos industriais pode se tornar estratégia corporativa para prevenção da geração de poluição e que traduz-se em ações de otimização da produção e melhoria contínua, o que relaciona-se a metodologia de Produção Mais Limpa (P+L). Assim, o objetivo desta pesquisa foi diagnosticar o gerenciamento de resíduos sólidos com enfoque nas premissas da metodologia de P+L em uma indústria gráfica e implementar um Programa de Gerenciamento de Resíduos Sólidos (PGRS) visando a otimização da produção industrial, equilíbrio sustentável dos processos e redução da geração de resíduos sólidos. Constatou-se que a gráfica em estudo teve a oportunidade de entender a importância do PGRS, da adoção de valores ecoeficientes e valor funcional ao fluxo do processo industrial, consolidando, portanto, as técnicas implementadas. A contribuição do PGRS pode ser observada pelo desempenho positivo das ações implementadas, que resultou num equilíbrio entre o consumo de matérias-primas e a geração de resíduos sólidos, possibilitando agregar valor ao produto final. A sinergia das ações implementadas, pautadas na integração do PGRS e P+L, possibilitou a melhoria do desempenho ambiental da gráfica, interferindo positivamente no desempenho operacional com a adequada operacionalização industrial. Os resultados apresentados sugerem que as indústrias do segmento gráfico e demais setores industriais explorem a metodologia adotada, adotando o PGRS como ferramenta de um sistema gestão ambiental integrado

Glycan shifting on hepatitis C virus (HCV) E2 glycoprotein is a mechanism for escape from broadly neutralizing antibodies

Hepatitis C virus (HCV) infection is a major cause of liver disease and hepatocellular carcinoma. Glycan shielding has been proposed to be a mechanism by which HCV masks broadly neutralizing epitopes on its viral glycoproteins. However, the role of altered glycosylation in HCV resistance to broadly neutralizing antibodies is not fully understood. Here, we have generated potent HCV neutralizing antibodies hu5B3.v3 and MRCT10.v362 that, similar to the previously described AP33 and HCV1, bind to a highly conserved linear epitope on E2. We utilize a combination of in vitro resistance selections using the cell culture infectious HCV and structural analyses to identify mechanisms of HCV resistance to hu5B3.v3 and MRCT10.v362. Ultra deep sequencing from in vitro HCV resistance selection studies identified resistance mutations at asparagine N417 (N417S, N417T and N417G) as early as 5 days post treatment. Comparison of the glycosylation status of soluble versions of the E2 glycoprotein containing the respective resistance mutations revealed a glycosylation shift from N417 to N415 in the N417S and N417T E2 proteins. The N417G E2 variant was glycosylated neither at residue 415 nor at residue 417 and remained sensitive to MRCT10.v362. Structural analyses of the E2 epitope bound to hu5B3.v3 Fab and MRCT10.v362 Fab using X-ray crystallography confirmed that residue N415 is buried within the antibody–peptide interface. Thus, in addition to previously described mutations at N415 that abrogate the β-hairpin structure of this E2 linear epitope, we identify a second escape mechanism, termed glycan shifting, that decreases the efficacy of broadly neutralizing HCV antibodies

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

Rôle des N-glycannes dans les fonctions des glycoprotéines d'enveloppe du virus de l'hépatite C

Le Virus de l Hépatite C (VHC) code deux glycoprotéines d enveloppe. E1 présente 4 ou 5 sites potentiels de N-glycosylation et E2 au moins 11. Ces sites potentiels de N-glycosylation sont fortement conservés, suggérant un rôle important dans les fonctions des glycoprotéines d enveloppe. Nous avons utilisé un système de pseudoparticules rétrovirales infectieuses exprimant les glycoprotéines d enveloppe du VHC mutées, pour étudier le rôle des glycannes de E1 et E2. Les mutants ont été appelés E1N1 à E1N4 pour E1 et E2N1 à E2N11 pour E2. Leur caractérisation nous a permis de définir 3 phénotypes. Dans le premier groupe (E1N3, E2N3, E2N5, E2N6, E2N7 et E2N9), l infectiosité des mutants est proche de celle du sauvage. Dans le second groupe (E1N1, E1N2, E1N4, E2N1 et E2N11), l infectiosité des mutants est réduite d au moins 50% par rapport au sauvage. Le dernier groupe contient les mutants ayant perdu leur infectiosité (E2N2, E2N4, E2N8 et E2N10). La perte d infectiosité des mutants E2N8 et E2N10 est due à un défaut d incorporation des hétérodimères E1E2 dans les ppVHC. Ce défaut d incorporation est lié un mauvais repliement des hétérodimères observé en immunoprécipitation avec des anticorps conformationnels et dans un test de pull-down avec CD81. L absence d infectiosité des mutants E2N2 et E2N4 indique qu ils sont impliqués dans le contrôle de l entrée virale. Nos résultats montrent que certains glycannes sont impliqués dans le repliement des protéines et d autres jouent un rôle dans l entrée virale.PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Glycosylation of hepatitis C virus envelope proteins.

International audienceEnveloped viruses are surrounded by a membrane derived from the host-cell that contains proteins called "envelope proteins". These proteins play a major role in virus assembly and entry. In most of the enveloped viruses, they are modified by N-linked glycosylation which is supposed to play a role in their stability, antigenicity and biological functions. Glycosylation is also known to play a major role in the biogenesis of proteins by being directly and/or indirectly involved in protein folding. Recent studies on hepatitis C virus (HCV) envelope proteins have revealed a complex interplay between cleavage by signal peptidase, folding and glycosylation. The knowledge that has been accumulated on the early steps of glycosylation of these proteins is presented in this review

Rôle du métapneumovirus dans les bronchiolites du nourrisson

LILLE2-BU Santé-Recherche (593502101) / SudocSudocFranceF

Rôle du virus respiratoire syncytial dans les bronchiolites du nourrisson

LILLE2-BU Santé-Recherche (593502101) / SudocSudocFranceF