520 research outputs found
A jurisprudência portuguesa dos tribunais superiores sobre exoneração do passivo restante (Breves notas sobre a admissão da exoneração e a cessão de rendimentos em particular)
No full textDesde 2004 que o Código da Insolvência e Recuperação de Empresas apresenta dois modelos insolvenciais para o tratamento da insolvência de pessoas singulares: por um lado, o modelo reeducativo, encarnado no plano de pagamentos; por outro o fresh start, consagrado com a exoneração do passivo restante. Esta última solução tem sido a opção da esmagadora maioria das pessoas singulares insolventes que, desde 2011, superam o número de processos de pessoas coletivas. Todavia, o sistema português tem sido criticado, não só pelo Memorando da Troika assinado entre o Estado Português, o BCE, a Comissão Europeia e o FMI, como pela própria doutrina e jurisprudência, pondo em evidência a necessidade de alteração do regime relativo às pessoas singulares. Aliás, tal exigência constava do referido Memorando, sem que o Governo português tenha adotado quaisquer medidas. Por outro lado, a recomendação da UE de março de 2014, relativa à recuperação e à insolvência, refere também a necessidade de redução do limite temporal de insolvências de pessoas singulares, nomeadamente no que concerne aos períodos de cessão dos rendimentos aos credores.
Nesta sede, verificamos que o regime português da insolvência, que conta já com mais de uma década de vigência, continua a apresentar fragilidades a nível da aplicação das normas, especialmente em dois pontos particulares – por um lado, a interpretação dos requisitos de acesso, que foi inicialmente feita de forma muito rígida pelos tribunais de 1.ª instância, impedindo o acesso à exoneração e, por outro, a concessão dos rendimentos necessários durante o período de cessão aos credores que, normalmente, desvaloriza as verdadeiras necessidades dos insolventes, dando um caráter punitivo, que o legislador não pretendeu atribuir, à insolvência. Este texto visa, pois, analisar brevemente a evolução jurisprudencial dos tribunais superiores na última década.info:eu-repo/semantics/publishedVersio
The success of particular acinetobacter baumannii clones: accumulating resistance and virulence inside a sugary shield
No full textThis is a pre-copyedited, author-produced version of an article accepted for publication in Journal of Antimicrobial Chemotherapy following peer review. The version of record Liliana Silva, Filipa Grosso, Carla Rodrigues, Magdalena Ksiezarek, Helena Ramos, Luísa Peixe, The success of particular Acinetobacter baumannii clones: accumulating resistance and virulence inside a sugary shield, Journal of Antimicrobial Chemotherapy, , dkaa453, https://doi.org/10.1093/jac/dkaa453 is available online at: https://academic.oup.com/jac/advance-article-abstract/doi/10.1093/jac/dkaa453/5956384?redirectedFrom=fulltextIn Portugal, carbapenem-resistant Acinetobacter baumannii (CRAB) has been associated with ST98, ST103 and ST208 (Oxford Scheme, Oxf) and a clone has usually been associated with a particular period of time. These clonal shifts were primarily explained by an increased antimicrobial resistance profile. Here we explore genomic and biochemical differences among these and more recent clones, which could further explain the diversity and evolution of this species.info:eu-repo/semantics/publishedVersio
Some Thoughts on Urban Sketching
No full textThe CRP department recognizes the importance of sketching as graphic thinking and a means to learn from what we see. Filipa Antunes, a renowned urban sketcher and artist who recently exhibited at the Louvre in Paris, presents some thoughts on how she approaches sketching as both a rational and an emotional process. All illustrations in this article are by the author. Follow Filipa\u27s work at https://www.facebook.com/DesenhoFilipaOliveiraAntunes
"Ready for BioData Management?" Training Data Stewards for Life Sciences: DS Lab 1, hosted by BioData.pt | ELIXIR PT
No full textThis training session is part of "Ready for BioData Management?" Training Data Stewards for Life Sciences, hosted by BioData.pt | ELIXIR PT.
The first part, "Ready for BioData Management?" Training Data Stewards for Life Sciences: Intro Course, is available here.
Lecture
Author
Affiliation
Assignment 1
Filipa Pereira
FCT | FCCN
Showcase: Best practices on data management at IGC
Tiago Paixão
BioData.pt | IGC
Pitch on main difficulties when filling a Data Management Plan:
Participants presented the DMP prepared during assignment 1, explaining the associated project, datasets, data types, and main difficulties and suggestions when using BioData.pt DSW.
Trainees
Data Management Plans & Assignment Feedback
Filipa Pereira
FCT | FCCN
Pitch based on the developed draft for institutional DM policies:
Participants described the main topics of a draft of their institutional policies, prepared during assignment 1, and explained the main requirements, difficulties, and existing policies.
Trainees
Institutional Policies on RDM & Exercise:
Group exercise: Responsibility of different stakeholders
Filipa Pereira
FCT | FCCN
LEARN Project Survey: Compare results with RDM Forum WG
Filipa Pereira
FCT | FCC
Recenzja: Trzy spojrzenia. O książce Nataszy Korczarowskiej-Różyckiej Inne spojrzenie...Wyobrażenia historii w filmach Wojciecha Jerzego Hasa, Jana Jakuba Kolskiego, Filipa Bajona i Anny Jadowskiej
No full textTHREE LOOKS. ON NATASZA KORCZAROWSKA-RÓŻYCKA’S BOOK INNE SPOJRZENIE... WYOBRAŻENIA HISTORII W FILMACH WOJCIECHA JERZEGO HASA, JANA JAKUBA KOLSKIEGO, FILIPA BAJONA I ANNY JADOWSKIEJThe article is a review of Natasza Korczarowska-Różycka’s last book Inne spojrzenie... Wyobrażenia historii w fi lmach Wojciecha Jerzego Hasa, Jana Jakuba Kolskiego, Filipa Bajona i Anny Jadowskiej Łódź 2013. According to the reviewer, the book is a bold attempt to combine film analysis with social issues. Korczarowska-Różycka proposed her own perspective of film reading on the intersection of close film analysis, sociological attitude and historical reflections about collective memory. She sees movie as a document of some socially established historical points of view or images, but also as a dynamic force, that is transforming and recreating these images. Her selection of directors and applied methodological basis allow her to avoid clichéd reflections on genre of historical cinema, but also lay her work open to the charge of certain arbitrariness. The author tries to not only present Korczarowska-Różycka’s book, but also bring out its theoretical background and place it in the broader context of memory studies.Translated by Aleksandra IdczakTHREE LOOKS. ON NATASZA KORCZAROWSKA-RÓŻYCKA’S BOOK INNE SPOJRZENIE... WYOBRAŻENIA HISTORII W FILMACH WOJCIECHA JERZEGO HASA, JANA JAKUBA KOLSKIEGO, FILIPA BAJONA I ANNY JADOWSKIEJThe article is a review of Natasza Korczarowska-Różycka’s last book Inne spojrzenie... Wyobrażenia historii w fi lmach Wojciecha Jerzego Hasa, Jana Jakuba Kolskiego, Filipa Bajona i Anny Jadowskiej Łódź 2013. According to the reviewer, the book is a bold attempt to combine film analysis with social issues. Korczarowska-Różycka proposed her own perspective of film reading on the intersection of close film analysis, sociological attitude and historical reflections about collective memory. She sees movie as a document of some socially established historical points of view or images, but also as a dynamic force, that is transforming and recreating these images. Her selection of directors and applied methodological basis allow her to avoid clichéd reflections on genre of historical cinema, but also lay her work open to the charge of certain arbitrariness. The author tries to not only present Korczarowska-Różycka’s book, but also bring out its theoretical background and place it in the broader context of memory studies.Translated by Aleksandra Idcza
Population struture, virulence and antibiotic resistance of Streptococcus agalactiae colonizing non-pregnant women
No full textStreptococcus agalactiae (GBS) é uma bactéria comensal dos tratos gastrointestinal e urogenital que se apresenta como o principal causador de mortalidade neonatal, causando ainda doença em adultos (idosos, imunocomprometidos). Foi estabelecida uma associação entre infeção neonatal e colonização urogenital materna e, em alguns países como Portugal, as gestantes são testadas para a colonização por GBS através de uma zaragatoa vaginal e ano-rectal, às 35-37 semanas de gravidez, sendo que a maioria dos estudos incide na caracterização de isolados de colonização de grávidas ou de infeção. No entanto, o estudo da colonização por GBS em mulheres não-grávidas, com vista à compreensão da estrutura populacional, serótipos, resistência a antimicrobianos (AMR) e fatores de virulência, é essencial para uma melhor prevenção e tratamento de infeções por GBS. Esta tese teve como objetivo a caracterização molecular de isolados de GBS obtidos de mulheres não-grávidas, de forma a avaliar a sua diversidade clonal, estabilidade, perfis de virulência e AMR. Adicionalmente, avaliou-se a capacidade da espectroscopia de FT-IR ATR em diferenciar linhagens de GBS. Dois processos de amostragem (PA) foram realizados para detetar colonização por GBS usando amostras de urina e zaragatoa vaginal. No primeiro PA foram incluídas 20 mulheres saudáveis e 1 mulher com infeções urinárias recorrentes, não-grávidas e em idade reprodutiva. Decorridos dois anos e meio, o segundo PA incluiu 10 das 20 mulheres saudáveis. As amostras foram processadas em diferentes meios de cultura/condições atmosféricas e a identificação dos isolados determinada por MALDI-TOF e confirmada pela deteção do gene dltS. Um total de 188 isolados foram obtidos de 9/21 e 3/10 mulheres no primeiro e segundo PA, respetivamente. Verificou-se alteração no estado de colonização em metade das mulheres entre os PAs. Curiosamente, 4 dadoras apresentaram GBS apenas na amostra de urina, sugerindo que esta poderá ser uma amostra biológica negligenciada para o rastreio de GBS em grávidas. Foram identificados cinco serótipos (CPS, II-VI), sendo o CPS II o mais frequente, e nove Sequence Types (ST) pertencentes a cinco complexos clonais (CC) (CC1: ST1 e ST2; CC10: ST8 e ST10; CC19: ST19, ST28; CC/ST23; CC/ST314), juntamente com o singleton ST529, sendo de salientar que ST10 e ST19 foram anteriormente associados a infeção. Foram identificados vários genes de virulência, exceto o marcador de hipervirulência hvgA, tendo-se verificado uma associação entre os perfis de virulência e os CCs (CC10/bac, CC19/rib). Foi detetada resistência à eritromicina, clindamicina e tetraciclina, associada à presença dos genes erm(B), tet(M) e tet(O). Dados preliminares de FT-IR ATR permitiram elaborar um modelo de discriminação baseado em serótipos, carecendo ainda de validação. Os isolados de GBS provenientes de colonização de mulheres não-grávidas caracterizados neste estudo permitiram a identificação de linhagens e fatores de virulência previamente associados a infeção. A estabilidade clonal encontrada numa mesma dadora contrastou com a instabilidade no estado de colonização. A maior deteção de GBS em urina em comparação com zaragatoa vaginal salienta a necessidade de refletir sobre os procedimentos atuais de testagem de GBS. O conhecimento da estrutura populacional e padrões de colonização de GBS é essencial para identificar as estirpes circulantes, de forma a orientar o desenvolvimento de uma profilaxia ainda mais efetiva.Streptococcus agalactiae (GBS) is a bacterium found in the gastrointestinal and urogenital tract and is the main responsible of neonatal mortality worldwide. It can also cause disease in adults, mainly the elderly and immunocompromised. Neonate infections have been associated with mother’s urogenital colonization and, in some countries like Portugal, pregnant women are screened for colonization by GBS, through a rectovaginal swab, between 35-37 weeks of gestation, with most studies focusing mainly the characterization of isolates colonizing pregnant women or causing infection. However, knowledge regarding GBS colonization among non-pregnant women, namely the population structure, serotype and virulence features, along with antimicrobial resistance, is essential for a better prevention and treatment of GBS infections. This thesis aimed the molecular characterization of GBS isolates collected from non-pregnant women, in order to evaluate their clonal diversity, stability, virulence profiles and antimicrobial resistance. Further, we evaluated the ability of FT-IR ATR spectroscopy to differentiate GBS lineages. Two sampling processes (SP) were performed to detect GBS colonization using urine and vaginal swabs samples. In the first SP, 20 healthy women and 1 woman presenting recurrent urinary tract infections, non-pregnant and in reproductive age, were included. Two and a half year later, 10 of the 20 healthy women were selected to proceed to the second SP. Different medium/atmospheric conditions were used to process the samples, isolates were identified by MALDI-TOF and confirmed by dltS gene amplification. A total of 188 isolates were obtained from 9/21 and 3/10 women in the first and second SPs, respectively. Change in colonization statues between SP occurred in half of the women. Curiously, GBS was detected only in urine in 4 women, suggesting that urine may be a neglected sample for the GBS universal screening that is performed in pregnant women. Five CPS types were identified (CPS II-VI), with CPS II being the most frequent. MLST analysis identified nine STs, belonging to five clonal complexes (CC1: ST1 and ST2; CC10: ST8 and ST10; CC19: ST19 and ST28; CC/ST23; CC/ST314), along with singleton ST529, being of note that ST10 and ST19 have been previously associated with infection. Several virulence genes were detected, except the hypervirulence biomarker hvgA. Interestingly, an association between CC and virulence genes profile was made, namely CC10/bac and CC19/rib. Resistance phenotype to erythromycin, clindamycin and tetracycline was observed, being possible to associate it with the presence of erm(B), tet(M) and tet(O) genes. Preliminary data on FT-IR ATR analysis enabled to elaborate a model for GBS discrimination based on CPS types, although still needing further validation. In this study we characterized GBS isolates colonizing non-pregnant women, identifying lineages and virulence factors associated with infection isolates. It is of note the clonal stability observed within the same donor, contrasting with the colonization status instability. Also, of note, the higher detection of GBS in urine in comparison with vaginal swabs, reflecting the need to rethink the current GBS screening procedures in pregnancy. GBS population structure and colonization patterns´ knowledge are essential to early identify GBS circulating strains and to guide the development of a more effective prophylaxis
Molecular recognition of tumor-associated antigens by lectins and antibodies
No full textEvery living cell on Earth is covered by glycans. They are inserted in proteins and lipids by a posttranslational modification called glycosylation. Their recognition by specific receptors is translated into distinct biological signals.
In cancer cells, a misregulation in expression and/or activity of glycosyltransferases, alters the mechanism of glycosylation, creating new glycan epitopes dubbed tumor-associated carbohydrate antigens (TACAs). These are recognized by various receptors, playing a major role in tumor immune responses and metastasis. To target cancer-associated glycan phenotype is crucial to disentangle the molecular recognition process that involves TACAs recognition and biosynthesis.
Therefore, NMR techniques were employed to investigate distinct glycan-protein systems: i) the molecular interactions between a mucin-1 (MUC1) related Tn-glycopeptide mimetic containing a non-natural amino acid and distinct antibodies by saturation transfer-difference (STD-NMR); ii) the molecular interactions between galectin-3 (Gal-3) and TF-antigen (TF-Thr and TF-peptide), by heteronuclear single quantum coherence 1H,15N-HSQC titrations, STD-NMR and line broadening analysis and iii) the glycosylation of MUC1 tandem repeated protein (G1VT3S4APDT8RPAPGS14T15APPAH20)4 by GalNAc-T3 using 1H,15N-HSQC and STD-NMR.
In i), the STD-NMR binding experiments show that all antibodies under study recognize the Tn-glycopeptide mimetic and point out structural differences that explain antibodies’ binding preferences.
In ii), the 1H,15N-HSQC titrations experiments indicate that Gal-3 binds both TF-derivatives. The dissociation constant KD estimated for both through chemical shift analysis also shows the same range of affinity (275 μM and 413 μM for TF-antigen and TF-peptide, respectively). STD-NMR results demonstrate that the protons from galactose in the TF-moiety govern the recognition process of Gal-3. In iii), the 1H,15N-HSQC experiments of MUC1 in presence of GalNAc-T3 show that the enzyme has preference to glycosylate first the Thr at –GVTS-, followed by the residue Thr at –GSTA-. STD-NMR confirms the cooperative mechanism between the lectin and catalytic domain of GalNAc-T3
A novel bacterium for 2-phenylethanol production
No full textFunding Information: This work was supported by the Associated Laboratory for Green Chemistry \u2013 LAQV (UIDB/50006/2020 and UIDP/50006/2020), the Associate Laboratory Institute for Health and Bioeconomy - i4HB (LA/P/0140/2020), the Applied Molecular Biosciences Unit \u2013 UCIBIO (UIDP/04378/2020 and UIDB/04378/2020) and the national project PTDC/CTM-CTM/29869/2017 and UID/DTP/04138/2019, which are financed by national funds from FCT - Funda\u00E7\u00E3o para a Ci\u00EAncia e a Tecnologia, I.P. (Portugal). This work also received financial support from ACINETOBACTER_POCI-01-0145-FEDER-042759. Funding Information: Ana R. Bernardino acknowledge FCT, I.P. for financial support through PhD fellowship SFRH/BD/138011/2018 and Filipa Grosso was supported by national funds through FCT in the context of the transitional norm (DL57/2016/CP1346/CT0034; ( https://doi.org/10.54499/DL57/2016/CP1346/CT0034 ). Publisher Copyright: © 2024A bacterium, Acinetobacter soli ANG344B, isolated from river water, exhibited an exceptional capacity to produce 2-phenylethanol (2-PE) using L-phenylalanine (L-Phe) as a precursor—a capability typically observed in yeasts rather than bacteria. Bioreactor experiments were conducted to evaluate the production performance, using glucose as the carbon source for cellular growth and L-Phe as the precursor for 2-PE production. Remarkably, A. soli ANG344B achieved a 2-PE concentration of 2.35 ± 0.26 g/L in just 24.5 h of cultivation, exhibiting a global volumetric productivity of 0.10 ± 0.01 g/L.h and a production yield of 0.51 ± 0.01 g2-PE/gL-Phe, a result hitherto reported only for yeasts. These findings position A. soli ANG344B as a highly promising microorganism for 2-PE production. Whole-genome sequencing of A. soli strain ANG344 revealed a genome size of 3.52 Mb with a GC content of 42.7 %. Utilizing the Rapid Annotation using Subsystem Technology (RAST) server, 3418 coding genes were predicted, including genes coding for enzymes previously associated with the metabolic pathway of 2-PE production in other microorganisms, yet unreported in Acinetobacter species. Through gene mapping, 299 subsystems were identified, exhibiting 30 % subsystem coverage. The whole genome sequence data was submitted to NCBI GeneBank with the BioProject ID PRJNA982713. These draft genome data offer significant potential for exploiting the biotechnological capabilities of A. soli strain ANG344 and for conducting further comparative genomic studies.publishersversionpublishe
Mechanism of glycosylation orchestrated by C1GalT1 and ST6GalNAc-I enzymes unveiled by NMR
No full textA O-glicosilação do tipo mucina é um mecanismo complexo altamente regulado pela atividade coordenada de enzimas específicas denominadas glicosiltransferases (GTs). No cancro, a desregulação da sua expressão e/ou atividade é comum, e conduz a uma glicosilação aberrante e à formação de antigénios de hidratos de carbono associados a tumores (TACAs). Os antigénios TF- (Galβ1-3GalNAcα1-O-Ser/Thr) e STn- (Neu5Acα2-6GalNAcα1-O-Ser/Thr) são dois dos TACAs mais encontrados em células cancerígenas. O antigénio TF é catalisado pela C1GalT1, uma GT com mecanismo de inversão. Esta enzima transfere uma molécula de galactose (Gal) do dador UDP-α-Gal para glicopéptidos que contêm o antigénio Tn (GalNAcα1-O-Ser/Thr). Este antigénio existe normalmente em células saudáveis mascarado por outros O-glicanos complexos. Contudo, no cancro, fica exposto. Já o antigénio STn é exclusivo das células cancerígenas. Através de um mecanismo de inversão, a enzima ST6GalNAc-I transfere um resíduo de ácido siálico (Neu5Ac) do dador CMP-β-Neu5Ac para substratos que contenham GalNAc. Contudo, apesar da relevância biológica das enzimas C1GalT1 e ST6GalNAc-I tanto na saúde como na doença, o seu mecanismo de ação a nível molecular ainda permanece relativamente desconhecido.
Tendo em conta a falta de informação estrutural, conformacional e mecanística destas enzimas, o foco desta tese é compreender o seu mecanismo molecular de O-glicosilação usando a mucina 1 (MUC1) como modelo. Desta forma, utilizou-se uma estratégia multidisciplinar que combina técnicas de RMN com simulações de dinâmica molecular, protocolos de biologia molecular, cristalografia de raio-X e outras técnicas biofísicas para o fazer. A tese está organizada em dois capítulos científicos onde se pretende determinar como a C1GalT1 reconhece os seus substratos a nível atómico, através de uma combinação de cristalografia de raio-X, métodos calorimétricos, simulações de dinâmica molecular e métodos de RMN baseados na deteção do ligando assim como elucidar o mecanismo de glicosilação da MUC1 pela C1GalT1 e a ST6GalNAc-I através de técnicas de RMN.
O capítulo 3 determina o processo de reconhecimento molecular de glicopéptidos contendo GalNAc pela C1GalT1. Neste capítulo foi demonstrado que a C1GalT1 é uma metaloenzima com um mecanismo de inversão do tipo SN2 que necessita de UDP-Gal e MnCl2 para se ligar especificamente a péptidos contendo GalNAc. A C1GalT1 reconhece os seus substratos através da unidade de GalNAc, porém a sequência peptídica estabelece interações adicionais que permitem estabilizar o complexo. Curiosamente, a C1GalT1 parece necessitar de uma conformação alternada para reconhecer os seus substratos, o que pode explicar a capacidade desta enzima para galactosilar ambos os resíduos Tn-Thr e Tn-Ser.
No capítulo 4, as preferências de glicosilação das enzimas C1GalT1 e ST6GalNAc-I foram determinadas para diferentes glicodomínios da MUC1, usando como modelo um glicodomínio com quatro repetições em tandem ((GVT*S*APDT*RPAPGS*T*APPAH)4, MUC14TR, * representa os possíveis sítios de glicosilação) desta mucina. Para a galactosilação observou-se que a atividade da C1GalT1 é influenciada por substratos com sítios de glicosilação adjacentes em substratos complexos, enquanto para sítios de glicosilação isolados a conformação e/ou sequência peptídica parece governar a sua atividade. O mesmo não foi observado para a ST6GalNAc-I. Enquanto a ST6GalNAc-I prefere glicosilar Tn-Thr, a C1GalT1 glicosila Tn-Thr e Tn-Ser identicamente. Em termos de conformação, a adição do segundo açúcar apenas afeta a conformação local do sítio de glicosilação, sem impactar a conformação global da MUC1. A alteração conformacional global ocorre após a adição de GalNAc pelas GalNAc-Ts. A informação estrutural obtida permitirá no futuro desenvolver de forma racional novos glicodomínios MUC1 com diferentes densidades de antigénios TF e STn.Mucin-type O-glycosylation is a complex mechanism regulated by the coordinated activity of specific glycosyltransferases (GTs). Altered regulation of several GTs is a common feature of cancer which yields tumour-associated carbohydrate antigens (TACAs). Two of the most popular TACAs are the TF- (Galβ1-3GalNAcα1-O-Ser/Thr) and STn- (Neu5Acα2-6GalNAcα1-O-Ser/Thr) antigens. The TF-antigen is formed by the inverting C1GalT1 enzyme, which transfers a Gal residue from the sugar donor UDP-α-Gal to Tn- (GalNAcα1-O-Ser/Thr) peptides. This antigen is naturally present as a hidden part of more complex O-glycans, however, truncation of O-glycans is a common characteristic of cancer cells, which exposes TF-epitopes in malignancy. The STn-antigen, exclusively found in cancer cells, is generated by the inverting ST6GalNAc-I enzyme, which adds a Neu5Ac residue from CMP-β-Neu5Ac sugar donor to GalNAc-containing substrates. Despite the significance of C1GalT1 and ST6GalNAc-I in health and disease, the molecular mechanisms underlying the recognition and catalysis of these enzymes remained elusive during the initial stages of this thesis.
On this basis, this thesis is focused on deciphering the molecular mechanism of mucin-1 (MUC1) O-glycosylation by C1GalT1 and ST6GalNAc-I, through the concerted integration of NMR with molecular dynamics (MD) simulations, and assisted by molecular biology protocols, X-ray crystallography and other biophysical techniques. This thesis is organized in two main scientific chapters: 1) the substrate molecular recognition mechanism of C1GalT1 through the combination of ligand-based NMR methods, X-ray crystallography, MD simulations and calorimetric measurements and 2) the elucidation of MUC1 glycosylation mechanism by C1GalT1 and ST6GalNAc-I unveiled by NMR.
Chapter 3 describes the structural insights for the substrate recognition and the synthesis of TF-antigen by C1GalT1. It is demonstrated that C1GalT1 is a metal-dependent inverting GT that follows an SN2 mechanism and needs UDP-Gal and MnCl2 for specific binding to Tn-peptides. The binding event is mainly driven by the GalNAc unit while the peptide sequence provides optimal kinetic and binding parameters. Key highlight is the evidence that C1GalT1 recognizes both Tn-Thr and Tn-Ser in a similar staggered conformation, which might explain the activity of C1GalT1 targeting both types of substrates in mucins.
In chapter 4, the glycosylation preferences of C1GalT1 and ST6GalNAc-I, targeting a four tandem repeat (TR) of MUC1 Tn-glycodomain ((GVT*S*APDT*RPAPGS*T*APPAH)4, MUC14TR, * Tn possible glycosylation sites), were scrutinized. Neighbouring glycosylation governs galactosylation by C1GalT1 in clusters of Tn-glycodomains, while in isolated glycosylation sites the peptide sequence or/and peptide conformation seems to play a role. For ST6GalNAc-I, this effect is not observed. However, ST6GalNAc-I prefers to glycosylate Tn-Thr over Tn-Ser, while C1GalT1 identically glycosylates Tn-Ser and Tn-Thr sites. Lastly, the introduction of the second sugar moiety affects the local conformation surrounding the glycosylation site, however, does not have a major impact on the peptide backbone conformation of MUC1. The main conformational change on the MUC1 peptide backbone is dictated by the first GalNAc residue introduced by GalNAc-Ts. All the structural information uncovered in chapter 4 can now be used to precise engineer TF- and STn-MUC1 glycodomains with different densities
Lactate-coated polyurea-siRNA dendriplex: a gene therapy-directed and metabolism-based strategy to impair glioblastoma (GBM) (Cancer Gene Therapy, (2025), 32, 6, (690-705), 10.1038/s41417-025-00906-8)
No full textPublisher Copyright: © The Author(s) 2025.Correction to: Cancer Gene Therapyhttps://doi.org/10.1038/s41417-025-00906-8, published online 27 April 2025 The article 'Lactate-coated polyurea-siRNA dendriplex: a gene therapy directed and metabolism-based strategy to impair glioblastoma (GBM)', written by Filipa Martins, Renata Arada, Hélio Barros, Paulo Matos, José Ramalho, Valentín Ceña, Vasco D. B. Bonifácio, Luís G. Gonçalves and Jacinta Serpa, was originally published under exclusive license to The Author(s), under exclusive licence to Springer Nature America, Inc. 2025.publishersversioninpres
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