Navegando por Autor "Kroon, Erna Geessien"
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Item Antiviral activity of Fridericia formosa (Bureau) L. G. Lohmann (Bignoniaceae) extracts and constituents.(2017) Brandão, Geraldo Célio; Kroon, Erna Geessien; Souza Filho, José Dias de; Oliveira, Alaíde Braga deA phytochemical study of Fridericia formosa (Bignoniaceae) ethanol extracts of leaves, stems, and fruits was guided by in vitro assays against vaccinia virus Western Reserve (VACV-WR), human herpes virus 1 (HSV-1), murine encephalomyocarditis virus (EMCV), and dengue virus type 2 (DENV-2) by the MTT method. All the ethanol extracts were active against DENV-2, HSV-1, and VACV-WRwith best results for the fruits extract against DENV-2 (SI > 38.2). For VACV-WRand HSV-1, EC50 values > 200 𝜇g mL−1 were determined, while no inhibition of the cytopathic effect was observed with EMCV. Five compounds were isolated and identified as the C-glucosylxanthones mangiferin (1), 2-O-trans-caffeoylmangiferin (2), 2-O-trans-coumaroylmangiferin (3), 2- O-trans-cinnamoylmangiferin (5), and the flavonoid chrysin (4). The most active compound was 2-O-trans-coumaroylmangiferin (3) with SI > 121.9 against DENV-2 and 108.7 for HSV-1. These results indicate that mangiferin cinnamoyl esters might be potential antiviral drugs.Item Chemistry and antiviral activity of Arrabidaea pulchra (Bignoniaceae).(2013) Brandão, Geraldo Célio; Kroon, Erna Geessien; Souza, Danielle E. R.; Souza Filho, José Dias de; Oliveira, Alaíde Braga deThe aim of the present work was to carry out a bioguided isolation of antiviral chemical constituents from an ethanol extract of leaves from Arrabidaea pulchra (Cham.) Sandwith (EEAPL) that had shown in vitro activity in a previous screening using DNA and RNA viruses. The activity of EEPAL was evaluated against the DNA viruses Human herpesvirus 1 (HSV-1) and Vaccinia virus Western Reserve (VACV-WR) as well as against the RNA viruses Murine encephalomyocarditis virus (EMCV), and Dengue virus 2 (DENV-2) by the 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) colorimetric assay. Cytotoxicity was determined in LLCMK2 and Vero cells and the Selectivity Indexes (SI) were calculated. The most potent effect was observed against DENV-2 (EC50 46.8 ± 1.6 μg mL−1; SI 2.7). For HSV-1 and VACV-WR EC50 values > 200 μg mL−1 were determined, while no inhibition of the cytopathic effect was observed with EMCV. Bioguided fractionation of EEAPL by partition between immiscible solvents followed by chromatography over a Sephadex LH20 column afforded two arylpropanoid glycosides, verbascoside (AP 1) and caffeoylcalleryanin (AP 2), along with a terpenoid, ursolic acid (AP 3). AP 1 and AP 3 exhibited similar anti-DENV-2 profiles, with SI values of 3.8 and 3.1, respectively, while AP 2 was the most effective anti-DENV-2 constituent, with a SI of 20.0. Our results show that A. pulchra leaves ethanol extract (EEAPL) affords compounds with antiviral activity, mainly against DENV-2.Item Himatanthus bracteatus stem extracts present antiflavivirus activity while an isolated sesquiterpene glucoside present only anti-Zika virus activity in vitro.(2019) Silva, Marlene Lourenço da; Stehmann, João Renato; Serafim, Mateus Sá Magalhães; Vale, Valdicley Vieira; Gontijo, Douglas da Costa; Brandão, Geraldo Célio; Kroon, Erna Geessien; Oliveira, Alaíde Braga deThe hexane and ethanol extracts from Himatanthus bracteatus (Apocynaceae) stems were evaluated for antiviral activity against Zika virus, yellow fever virus and dengue virus 2 and for cytotoxicity in Vero cells by MTT assay. The ethanol extract showed good antiviral activity against the three viruses with selective indexes (SI) > 10 and its fractionation led to the isolation of the known plumieride that was active only against Zika virus (SI of 15.97).Item Identification of a phylogenetically distinct orthobunyavirus from group C.(2011) Magalhães, Cíntia Lopes de Brito; Drumond, Betânia Paiva; Novaes, Renata Franco Vianna; Quinan, Bárbara Rezende; Magalhães, José Carlos de; Santos, João Rodrigues dos; Pinto, Carla do Amaral; Assis, Marieta Torres de Abreu; Bonjardim, Cláudio Antônio; Kroon, Erna Geessien; Ferreira, Paulo César PeregrinoApeu virus (APEUV) (family Bunyaviridae, genus Orthobunyavirus) was plaque purified and characterised by serological and molecular analysis. Neutralising assays confirmed cross-reactivity between purified APEUV clones and the Caraparu virus complex of group C orthobunyaviruses. Partial sequencing of the L, M and S segments of one APEUV clone (APEUV-CL5) was carried out. A phylogenetic tree constructed with the L amino acid sequences clustered APEUV-CL5 within the genus Orthobunyavirus, confirming its serological classification. Analysis of M segment sequences clustered APEUV-CL5 in the Caraparu virus complex (Group C), in agreement with serological tests and previous molecular characterisation. However, the sequence of the nucleocapsid gene (N) gave low identity values when compared to those of the group C viruses. The phylogenetic tree based on N nucleotide sequences clustered APEUV-CL5 next to the California and Bwamba groups. This remarkable S nucleotide variability suggests that APEUV-CL5 could be a genetic reassortant and that this evolutionary mechanism is present in the history of the group C viruses.Item Morphological and molecular characterization of the Poxvirus BeAn 58058.(1998) Fonseca, Flávio Guimarães da; Lanna, Maria Célia da Silva; Campos, Marco Antônio da Silva; Kitajima, Elliot Watanabe; Péres, José Noronha; Golgher, Romain Rolland; Ferreira, Paulo César Peregrino; Kroon, Erna GeessienBeAn 58058 virus (BAV) was isolated from an Oryzomis rodent in Brazil. BAV was shown to be antigenically related to another poxvirus also isolated in Brazil, the Cotia virus, but it remained ungrouped. Electron microscopy revealed that BAV has a typical poxvirus morphology. The Hind III DNA profile of BAV genome was similar with that of VV WR and Lister, but some differences in the profile were detected. We have also detected the presence of genes homologous to vaccinia virus (VV WR) genes in the genome of BAV. Genes related to vaccinia thymidine kinase (TK) gene and vaccinia growth factor (VGF) gene were found. The patterns of TK and VGF mRNA transcripts described for vaccinia virus infected cells were observed in BAV infected cells. Nucleotide sequence of BAV VGF homologous gene was similar to VVWRVGF sequences. This similarity was further seen when cross-hybridization of total genomes of BAV and VV was done. Polypeptide synthesis of BAV and vaccinia in infected cells also showed similar profiles. The genetic data was used to construct a phylogenetic tree where BAV and VV were placed at the same cluster. Based on our findings we propose that BAV is a vaccinia virus variant.Item Multi-walled carbon nanotubes functionalized with recombinant Dengue virus 3 envelope proteins induce significant and specific immune responses in mice.(2017) Versiani, Alice Freitas; Astigarraga, Ruiz Gerhardt; Rocha, Eliseu Soares de Oliveira; Barboza, Ana Paula Moreira; Kroon, Erna Geessien; Rachid, Milene Alvarenga; Souza, Daniele da Glória de; Ladeira, Luiz Orlando; Stancioli, Edel Figueiredo Barbosa; Vasconcelos, Ado Jorio de; Fonseca, Flávio Guimarães daDengue is the most prevalent arthropod-borne viral disease in the world. In this article we present results on the development, characterization and immunogenic evaluation of an alternative vaccine candidate against Dengue.Item A tetravalent dengue nanoparticle stimulates antibody production in mice.(2012) Silva, Elisângela F.; Orsi, Mariana; Andrade, Ângela Leão; Domingues, Rosana Zacarias; Silva, Breno de Mello; Araújo, Helena Rocha Corrêa de; Pimenta, Paulo Filemon Paolucci; Diamond, Michael S.; Rocha, Eliseu S. O.; Kroon, Erna Geessien; Malaquias, Luiz Cosme Cotta; Coelho, Luiz Felipe LeomilDengue is a major public health problem worldwide, especially in the tropical and subtropical regions of the world. Infection with a single Dengue virus (DENV) serotype causes a mild, self-limiting febrile illness called dengue fever. However, a subset of patients experiencing secondary infection with a different serotype progresses to the severe form of the disease, dengue hemorrhagic fever/dengue shock syndrome. Currently, there are no licensed vaccines or antiviral drugs to prevent or treat dengue infections. Biodegradable nanoparticles coated with proteins represent a promising method for in vivo delivery of vaccines.Item The dengue virus nonstructural protein 1 (NS1) increases NF-kB transcriptional activity in HepG2 cells.(2011) Silva, Breno de Mello; Sousa, Lirlândia Pires de; Gomes Ruiz, Alessandra C.; Leite, Flávia Gama Gomes; Teixeira, Mauro Martins; Fonseca, Flávio Guimarães da; Pimenta, Paulo Filemon Paolucci; Ferreira, Paulo César Peregrino; Kroon, Erna Geessien; Bonjardim, Cláudio AntônioDengue virus nonstructural protein 1 (NS1) is a glycoprotein involved in viral RNA replication. NS1 associates with host cell proteins and can be found in lipid raft domains on the host cell surface, suggesting an involvement in signal transduction events. In this work, we observed that NS1 expression in HepG2 cells increases nuclear translocation of NF-jB p65 protein, which was paralleled by DNA-protein complex formation. Luciferase assays showed an increase in NF-jB transcriptional activities in NS1-expressing cells when compared to parental cells. NS1 may enhance NF-jB function in host cells and contribute to the pathogenesis of dengue.Item Virulence in murine model shows the existence of two distinct populations of Brazilian vaccinia virus strains.(2008) Ferreira, Jaqueline Maria Siqueira; Drumond, Betânia Paiva; Guedes, Maria Isabel Maldonado Coelho; Xavier, Marcelo Antônio Pascoal; Leite, Camila Megale Almeida; Arantes, Rosa Maria Esteves; Mota, Bruno Eduardo Fernandes; Abrahão, Jônatas Santos; Alves, Pedro Augusto; Oliveira, Fernando Meireles; Ferreira, Paulo César Peregrino; Bonjardim, Cláudio Antônio; Lobato, Zélia Inês Portela; Kroon, Erna GeessienBrazilian Vaccinia virus had been isolated from sentinel mice, rodents and recently from humans, cows and calves during outbreaks on dairy farms in several rural areas in Brazil, leading to high economic and social impact. Some phylogenetic studies have demonstrated the existence of two different populations of Brazilian Vaccinia virus strains circulating in nature, but little is known about their biological characteristics. Therefore, our goal was to study the virulence pattern of seven Brazilian Vaccinia virus strains. Infected BALB/c mice were monitored for morbidity, mortality and viral replication in organs as trachea, lungs, heart, kidneys, liver, brain and spleen. Based on the virulence potential, the Brazilian Vaccinia virus strains were grouped into two groups. One group contained GP1V, VBH, SAV and BAV which caused disease and death in infected mice and the second one included ARAV, GP2V and PSTV which did not cause any clinical signals or death in infected BALB/ c mice. The subdivision of Brazilian Vaccinia virus strains into two groups is in agreement with previous genetic studies. Those data reinforce the existence of different populations circulating in Brazil regarding the genetic and virulence characteristics.