Liliana Rodrigues, Renata Bento Cunha, Tatiana Vassilevskaia, Miguel Viveiros, Celso Cunha,
In December 2019, the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19) was first identified in the province of Wuhan, China. Since then, there have been over 400 million confirmed cases and 5.8 million deaths by COVID-19 reported worldwide. The urgent need for therapies against SARS-CoV-2 led researchers to use drug repurposing approaches. This strategy allows the reduction in risks, time, and costs associated with drug ...
Tópico(s): Computational Drug Discovery Methods
2022 - Multidisciplinary Digital Publishing Institute | Molecules
Natália Freitas, Celso Cunha, Stephan Menne, Severin O. Gudima,
ABSTRACT A natural subviral agent of human hepatitis B virus (HBV), hepatitis delta virus (HDV), requires only the envelope proteins from HBV in order to maintain persistent infection. HBV surface antigens (HBsAgs) can be produced either by HBV replication or from integrated HBV DNA regardless of replication. The functional properties of the integrant-generated HBsAgs were examined using two human hepatocellular carcinoma-derived cell lines, Hep3B and PLC/PRF/5, that contain HBV integrants but do not ...
Tópico(s): Liver Disease Diagnosis and Treatment
2014 - American Society for Microbiology | Journal of Virology
Natália Freitas, Kenji Abe, Celso Cunha, Stephan Menne, Severin O. Gudima,
This study examined how the envelope proteins of 25 variants of hepatitis B virus (HBV) genotypes A to I support hepatitis delta virus (HDV) infectivity. The assembled virions bore the same HDV ribonucleoprotein and differed only by the HBV variant-specific envelope proteins coating the particles. The total HDV yields varied within a 122-fold range. A residue Y (position 374) in the HDV binding site was identified as critical for HDV assembly. Virions that bound antibodies, which recognize the region ...
Tópico(s): Hepatitis Viruses Studies and Epidemiology
2014 - American Society for Microbiology | Journal of Virology
Joana Cavaco-Silva, Ana Abecasis, Ana Cláudia Miranda, José Poças, Jorge Narciso, Maria João Águas, Fernando Maltêz, Isabel Almeida, Isabel Germano, António Diniz, Maria de Fátima Gonçalves, Perpétua Gómes, Celso Cunha, Ricardo Camacho,
To characterize the HIV-2 integrase gene polymorphisms and the pathways to resistance of HIV-2 patients failing a raltegravir-containing regimen, we studied 63 integrase strand transfer inhibitors (INSTI)-naïve patients, and 10 heavily pretreated patients exhibiting virological failure while receiving a salvage raltegravir-containing regimen. All patients were infected by HIV-2 group A. 61.4% of the integrase residues were conserved, including the catalytic motif residues. No INSTI-major resistance ...
Tópico(s): Biochemical and Molecular Research
2014 - Public Library of Science | PLoS ONE
Carolina Alves, Cristina Branco, Celso Cunha,
The hepatitis delta virus (HDV) is distributed worldwide and related to the most severe form of viral hepatitis. HDV is a satellite RNA virus dependent on hepatitis B surface antigens to assemble its envelope and thus form new virions and propagate infection. HDV has a small 1.7 Kb genome making it the smallest known human virus. This deceivingly simple virus has unique biological features and many aspects of its life cycle remain elusive. The present review endeavors to gather the available information ...
Tópico(s): Hepatitis Viruses Studies and Epidemiology
2013 - Hindawi Publishing Corporation | Advances in Virology
Marta Mendes, Daniel Pérez-Hernández, Jesús Vázquez, Ana Varela Coelho, Celso Cunha,
Hepatitis delta virus (HDV) infection greatly increases the risk of hepatocellular carcinoma in hepatitis B virus chronically infected patients. HDV is highly dependent on host factors for accomplishment of the replication cycle. However, these factors are largely unknown and the mechanisms involved in the pathogenicity of the virus still remain elusive. Here, we made use of the HEK-293 cell line, which was engineered in order to mimic HDV replication. Five different proteomes were analyzed and compared ...
Tópico(s): Animal Virus Infections Studies
2013 - Elsevier BV | Journal of Proteomics
Joana Cavaco-Silva, M.J. Aleixo, Kristel Van Laethem, Diogo Faria, Emília Valadas, João Gonçalves, Perpétua Gómes, Anne–Mieke Vandamme, Celso Cunha, Ricardo Camacho,
To investigate mutations selected in viruses from HIV-2-infected patients failing a highly active antiretroviral treatment (HAART) regimen including atazanavir/ritonavir.Twenty-eight HIV-2-infected patients previously exposed to atazanavir/ritonavir and failing therapy were studied. The protease (PR) gene was amplified and sequenced, and mutations emerging under atazanavir/ritonavir selective pressure were reported.The I50L mutation emerged in 4 out of 28 HIV-2-infected patients failing a HAART regimen ...
Tópico(s): Biochemical and Molecular Research
2012 - Oxford University Press | Journal of Antimicrobial Chemotherapy
Natália Freitas, Jessica Salisse, Celso Cunha, Ilia Toshkov, Stephan Menne, Severin O. Gudima,
Hepatitis delta virus (HDV) is a natural subviral agent of human hepatitis B virus (HBV). HDV enhances liver damage during concomitant infection with HBV. The molecular pathogenesis of HDV infection remains poorly understood. To advance our understanding of the relationship between HDV infection and liver cancer, it was determined whether HDV could infect in vivo the cells of hepadnavirus-induced hepatocellular carcinoma (HCC). Woodchucks ( Marmota monax ) that were chronically infected with HBV-related ...
Tópico(s): Animal Virus Infections Studies
2012 - Lippincott Williams & Wilkins | Hepatology
Ana Casaca, Margarida Fardilha, Edgar da Cruz e Silva, Celso Cunha,
Abstract Background Hepatitis delta virus (HDV) is considered to be a satellite virus of the Hepatitis B virus. The genome consists of a 1679 nt ssRNA molecule in which a single ORF was identified. This ORF codes for a unique protein, the Delta antigen (HDAg). During transcription, two forms, small (S-HDAg; p24) and large (L-HDAg; p27) of this antigen are derived as a result of an editing mechanism catalyzed by cellular adenosine deaminase 1. Despite its simplicity, little is still known about the host ...
Tópico(s): Viral gastroenteritis research and epidemiology
2011 - BioMed Central | Virology Journal
Background Mathematical models have shown to be extremely helpful in understanding the dynamics of different virus diseases, including hepatitis B. Hepatitis D virus (HDV) is a satellite virus of the hepatitis B virus (HBV). In the liver, production of new HDV virions depends on the presence of HBV. There are two ways in which HDV can occur in an individual: co-infection and super-infection. Co-infection occurs when an individual is simultaneously infected by HBV and HDV, while super-infection occurs ...
Tópico(s): Liver Disease Diagnosis and Treatment
2010 - Public Library of Science | PLoS ONE
In eukaryotes, the nuclear membrane provides a physical barrier to the passive diffusion of macromolecules from and into the cytoplasm. Nucleocytoplasmic traffic occurs through highly specialized structures known as nuclear pores, and involves the participation of a special class of transport proteins. Active transport across the nuclear pores is an energy-dependent process that relies on the activity of Ran-GTPases both in the nuclear and cytoplasmic compartments. Nuclear import of proteins is ...
Tópico(s): RNA regulation and disease
2009 - Bentham Science Publishers | Current Genomics
Sergio Regufe da Mota, Marta Mendes, Deborah Penque, Ana Varela Coelho, Celso Cunha,
Tópico(s): HIV Research and Treatment
2008 - Elsevier BV | Journal of Proteomics
Sergio Regufe da Mota, Marta Mendes, Natália Freitas, Deborah Penque, Ana Varela Coelho, Celso Cunha,
Tópico(s): Endoplasmic Reticulum Stress and Disease
2008 - Elsevier BV | Journal of Proteomics
Carolina Alves, Natália Freitas, Celso Cunha,
Tópico(s): Virus-based gene therapy research
2007 - Elsevier BV | Virology
Ana Afonso, Paul Hunt, Sandra Cheesman, Ana Catarina Alves, Celso Cunha, V. do Rosário, Pedro Cravo,
Resistance of Plasmodium falciparum to drugs such as chloroquine and sulfadoxine-pyrimethamine is a major problem in malaria control. Artemisinin (ART) derivatives, particularly in combination with other drugs, are thus increasingly used to treat malaria, reducing the probability that parasites resistant to the components will emerge. Although stable resistance to artemisinin has yet to be reported from laboratory or field studies, its emergence would be disastrous because of the lack of alternative ...
Tópico(s): Computational Drug Discovery Methods
2006 - American Society for Microbiology | Antimicrobial Agents and Chemotherapy
Maria João Collares‐Pereira, Sofia Couceiro, Isabel da Franca, Klaus Kurtenbach, Stefanie Schäfer, Liliana Vitorino, Lígia Antunes Gonçalves, Susana Baptista, Maria Luísa Vieira, Celso Cunha,
The first human isolate of Borrelia lusitaniae recovered from a Portuguese patient with suspected Lyme borreliosis is described. This isolate, from a chronic skin lesion, is also the first human isolate of Borrelia in Portugal. Different phenotypic and molecular methods are used to characterize it.
Tópico(s): Vector-Borne Animal Diseases
2004 - American Society for Microbiology | Journal of Clinical Microbiology
João Paulo Tavanez, Celso Cunha, MARIA C.A. SILVA, Ezio David, JO O MONJARDINO, Maria Carmo‐Fonseca,
Hepatitis delta virus (HDV) infection of individuals infected with hepatitis B virus (HBV) is associated with more severe liver damage and an increased risk of fulminant disease. HDV is a single-stranded RNA virus that encodes a single protein, the delta antigen, which is expressed in two forms, small (S-HDAg) and large (L-HDAg). Here we show that although HDV ribonucleoproteins are mainly detected in the nucleus, they are also present in the cytoplasm of cells infected with HDV or transfected with ...
Tópico(s): Animal Virus Infections Studies
2002 - Cold Spring Harbor Laboratory Press | RNA
Dominique Vautier, P. Chesné, Celso Cunha, Ângelo Calado, Jean‐Paul Renard, Maria Carmo‐Fonseca,
ABSTRACT A unique feature of certain members of the heterogeneous nuclear ribonucleoprotein (hnRNP) family of proteins is that they shuttle continuously between nucleus and cytoplasm and their accumulation in the nucleus is transcription-dependent. An extensively characterised protein of this group is hnRNP A1. To date, most studies addressing the transcription-dependent transport of hnRNP A1 have been performed on cultured cell lines treated with transcription inhibitors. Here we have analysed the ...
Tópico(s): Genomics and Chromatin Dynamics
2001 - The Company of Biologists | Journal of Cell Science
Jorge Soares, António E. Pinto, Celso Cunha, Saudade Andr�, Isabel Bar�o, J. Meneses Sousa, Marília Cravo,
The global DNA methylation of 136 breast lesions (117 primary invasive carcinomas, 5 benign phyllodes tumors, 11 fibroadenomas, and 3 sclerosing adenosis) and their respective adjacent parenchyma was analyzed using an in vitro enzyme assay.In the group of patients with breast carcinoma, DNA hypomethylation was correlated with clinical and pathologic parameters known to affect disease prognosis. Histopathologic type, disease stage, and tumor grade were evaluated according to the World Health Organization ...
Tópico(s): Genetic Syndromes and Imprinting
1999 - Wiley | Cancer
Celso Cunha, Joao P. Monjardino, DOROTHY CHANG, Sabine Krause, Maria Carmo‐Fonseca,
Hepatitis delta virus (HDV) is a human pathogen that can greatly increase the severity of liver damage caused by an hepatitis B infection. HDV contains a circular, single-stranded RNA genome that encodes a unique protein, the delta antigen. Two forms of the delta antigen, δAg-S and δAg-L, are derived from a single open reading frame by RNA editing. Here we analyze the subcellular distribution of HDV RNA and its spatial relationship to known intranuclear structures. The human hepatoma cell line Huh7 ...
Tópico(s): Herpesvirus Infections and Treatments
1998 - Cold Spring Harbor Laboratory Press | RNA
Peter Jordan, Celso Cunha, Maria Carmo‐Fonseca,
TFIIH is a general transcription factor for RNA polymerase II that in addition is involved in DNA excision repair. TFIIH is composed of eight or nine subunits and we show that at least four of them, namely cdk7, cyclin H, MAT1, and p62 are localized in the coiled body, a distinct subnuclear structure that is transcription dependent and highly enriched in small nuclear ribonucleoproteins. Although coiled bodies do not correspond to sites of transcription, in vivo incorporation of bromo-UTP shows ...
Tópico(s): RNA Research and Splicing
1997 - American Society for Cell Biology | Molecular Biology of the Cell
Maria Carmo‐Fonseca, Celso Cunha, Noélia Custódio, Célia Carvalho, Peter Jordan, João Ferreira, Leonor Parreira,
At present several lines of evidence indicate that the nucleus is functionally compartmentalized into discrete structures with defined properties. For instance, it is well established that the molecular machines involved in replication, transcription, and RNA processing assemble into morphological entities but it remains unclear whether these correspond to autonomous "organelles" or rather represent temporary accumulations of either active factors recruited onto DNA templates or inactive factors ...
Tópico(s): RNA Research and Splicing
1996 - Elsevier BV | Experimental Cell Research
Filomena Manjate, Eva D. João, Percina Chirinda, Marcelino Garrine, Delfino Vubil, Nélio Nobela, Karen L. Kotloff, James P. Nataro, Tacilta Nhampossa, Sozinho Acácio, Jacqueline E. Tate, Umesh D. Parashar, Jason M. Mwenda, Pedro L. Alonso, Martin M. Nyaga, Celso Cunha, Inácio Mandomando,
Group A rotaviruses remain the leading cause of diarrhoea in children aged <5 years. Mozambique introduced rotavirus vaccine (Rotarix®) in September 2015. We report rotavirus genotypes circulating among symptomatic and asymptomatic children in Manhiça District, Mozambique, pre- and post-vaccine introduction. Stool was collected from enrolled children and screened for rotavirus by enzyme-immuno-sorbent assay. Positive specimens were genotyped for VP7 (G genotypes) and VP4 (P genotypes) by the conventional ...
Tópico(s): Viral Infections and Immunology Research
2022 - Multidisciplinary Digital Publishing Institute | Viruses
Produção Nacional
As tres gramaticas de Celso Cunha e seu perfil como construtoras e confirmadoras de um modelo linguistico-literario. O percurso historico dessas obras, a descricao comentada ...
Tópico(s): Linguistics and Education Research
2004 - UNIVERSIDADE DE SÃO PAULO | Filologia e Linguística Portuguesa
Celso Cunha, João Paulo Tavanez, Severin O. Gudima,
Hepatitis delta virus (HDV) is the etiologic agent of the most severe form of virus hepatitis in humans.Sharing some structural and functional properties with plant viroids, the HDV RNA contains a single open reading frame coding for the only virus protein, the Delta antigen.A number of unique features, including ribozyme activity, RNA editing, rolling-circle RNA replication, and redirection for a RNA template of host DNA-dependent RNA polymerase Ⅱ, make this small pathogen an excellent model to ...
Tópico(s): Hepatitis Viruses Studies and Epidemiology
2015 - | World Journal of Virology
Miguel Landum, Cátia Ferreira, Manuela Calado, Ana Margarida Alho, Isabel Maurício, José Meireles, Luís Madeira de Carvalho, Celso Cunha, Silvana Belo,
Wolbachia pipiens, an intracellular endosymbiont bacteria of filarial nematodes, has been implicated in the pathogenesis of filarial diseases, in particular in heavy Dirofilaria spp. infections. Antibiotic therapy (doxycycline) against Wolbachia has been proven to be suitable adjunct therapy, prior to adulticide treatment of canine dirofilariosis. Despite its importance, investigation on the Wolbachia/Dirofilaria complex in Portugal had not been undertaken so far. This study reports the first detection ...
Tópico(s): Autism Spectrum Disorder Research
2014 - Elsevier BV | Veterinary Parasitology
Jorge Barbosa Soares, António E. Pinto, Celso Cunha, Saudade André, Isabel Barão, J. Meneses Sousa, Marília Cravo,
BACKGROUND The global DNA methylation of 136 breast lesions (117 primary invasive carcinomas, 5 benign phyllodes tumors, 11 fibroadenomas, and 3 sclerosing adenosis) and their respective adjacent parenchyma was analyzed using an in vitro enzyme assay. METHODS In the group of patients with breast carcinoma, DNA hypomethylation was correlated with clinical and pathologic parameters known to affect disease prognosis. Histopathologic type, disease stage, and tumor grade were evaluated according to the ...
Tópico(s): Genetic Syndromes and Imprinting
1999 - Wiley | Cancer
Maria Fernanda Barros, Celso Cunha, João Costa,
Infection of Vero cells with African swine fever (ASF) virus resulted in a marked increase of DNase active on single-stranded DNA (ss-DNase). No increase was observed for double-stranded DNA-specific nuclease activity. In contrast to uninfected cell ss-DNase, which has a pH optimum at pH range 8.5-9, virus-induced ss-DNase is most active at pH 7. Differences in sensitivity to several ions and other modifications of the reaction mixture and considerable difference in reaction kinetics suggest that ...
Tópico(s): Viral gastroenteritis research and epidemiology
1986 - Elsevier BV | Virology
Produção Nacional
Revisado por pares
Eliene Pires Carvalho, Efigênia Guariento Ferreira, José Celso da Cunha, Conrado de Souza Rodrigues, Nilton da Silva Maia,
The steel-concrete bond is a fundamental property in reinforced concrete structures. Although there are several studies on the steel-concrete bond, few of them have evaluated the performance of reinforcing bars with diameters less than 10.0 mm, which includes 5.0, 6.3, and 8.0 mm diameters, which are normally used in reinforced-concrete elements. This study experimentally evaluates the bond between thin steel bars and concrete of 25MPa compression strength. Three types of methods of testing the ...
Tópico(s): Innovative concrete reinforcement materials
2017 - Brazilian Society of Mechanical Sciences and Engineering | Latin American Journal of Solids and Structures
João Paulo Tavanez, R. Caetano, Cristina Branco, Inês Margarida Bernardo Brito, Ana Miragaia‐Pereira, Tatiana Vassilevskaia, Ana S. Quina, Celso Cunha,
Hepatitis delta virus (HDV) is the agent responsible for the most severe form of human viral hepatitis. The HDV genome consists of a single-stranded circular RNA molecule that encodes for one single protein, the delta antigen. Given its simplicity, HDV must make use of several host cellular proteins to accomplish its life cycle processes, including transcription, replication, post-transcriptional, and post-translational modifications. Consequently, identification of the interactions established between ...
Tópico(s): RNA Research and Splicing
2020 - Wiley | FEBS Journal