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Search Results: 1 - 10 of 190127 matches for " Erna G. Kroon "
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Vaccinia virus regulates expression of p21WAF1/Cip1 in A431 cells
Andrade, Anderson A;Brasil, Bruno SAF;Pereira, Anna CTC;Ferreira, Paulo CP;Kroon, Erna G;Bonjardim, Cláudio A;
Memórias do Instituto Oswaldo Cruz , 2010, DOI: 10.1590/S0074-02762010000300005
Abstract: in this paper, we provide evidence that both the mrna and protein levels of the cyclin-dependent kinase (cdk) inhibitor p21waf1/cdk-interacting protein 1 (cip1) increase upon infection of a431 cells with vaccinia virus (vacv). in addition, the vacv growth factor (vgf) seems to be required for the gene expression because infection carried out with the mutant virus vacv-vgf- revealed that this strain was unable to stimulate its transcription. our findings are also consistent with the notion that the vgf-mediated change in p21waf1/cip1 expression is dependent on tyrosine kinase pathway(s) and is partially dependent on mitogen-activated protein kinase/extracellular-signal regulated kinase 1/2. we believe that these pathways are biologically significant because vacv replication and dissemination was drastically affected when the infection was carried out in the presence of the relevant pharmacological inhibitors.
Antiviral activities of plants occurring in the state of Minas Gerais, Brazil: Part 2. Screening Bignoniaceae species Atividade antiviral de extratos de plantas coletadas no estado de Minas Gerais: Parte 2. Triagem de Bignoniaceae
Geraldo Célio Brand?o,Erna G. Kroon,Jo?o Rodrigues dos Santos,Jo?o Renato Stehmann
Revista Brasileira de Farmacognosia , 2010,
Abstract: Ethanol extracts of eighteen Bignoniaceae species have been evaluated by the MTT assay for cytotoxicity in Vero cells and for antiviral activity against Human herpes virus type 1, Vaccinia virus and murine Encephalomyocarditis virus. Among such species, seven are reported to be of traditional medicinal use No cytotoxicity was observed for most of the extracts up to the concentration of 500 μg/mL. Fourteen (50%) of the 28 extracts assayed have disclosed antiviral activity with EC50 values in the range of 4.6+0.3 to 377.2+17.7 μg/mL. Only two species, Arrabidaea samydoides and Callichlamys latifolia, have shown activity against all the three viruses. The extracts were chemically characterized by their TLC and HPLC-DAD profiles. Mangiferin is the major constituent of A. samydoides but the isolated compound has been less active than the crude extract. This is the first report on the antiviral evaluation of the eighteen Bignoniaceae species assayed. Extratos etanólicos de dezoito espécies vegetais pertencentes à família Bignoniaceae, das quais sete s o descritas como de uso medicinal, foram avaliados, pelo ensaio colorimétrico do MTT, para atividades citotóxica, em células Vero, e antiviral, frente aos vírus herpes simplex-tipo 1, vaccinia e encefalomiocardite murina. A maior parte dos extratos n o apresentou citotoxicidade até a concentra o de 500 μg/mL. Dos 28 extratos testados quatorze (50%) apresentaram atividade antiviral com valores de CE50 na faixa de 4,6+03 a 377,2+17,7 μg/mL. Somente duas espécies, Arrabidaea samydoides e Callichlamys latifolia, foram ativas frente aos três vírus. Os extratos foram caracterizados pelos seus perfís cromatográficos em CCD e CLAE-FR. Análises por CLAE-FR mostraram que a mangiferina é o constituinte majoritário em A. samydoides mas a substancia isolada foi menos ativa do que o extrato bruto. Esta é a primeira vez que se relata a atividade antiviral de extratos das dezoito espécies avaliadas.
Antiviral activities of plants occurring in the state of Minas Gerais, Brazil: Part 2. Screening Bignoniaceae species
Brand?o, Geraldo Célio;Kroon, Erna G.;Santos, Jo?o Rodrigues dos;Stehmann, Jo?o Renato;Lombardi, Júlio A.;Oliveira, Alaíde Braga de;
Revista Brasileira de Farmacognosia , 2010, DOI: 10.1590/S0102-695X2010005000035
Abstract: ethanol extracts of eighteen bignoniaceae species have been evaluated by the mtt assay for cytotoxicity in vero cells and for antiviral activity against human herpes virus type 1, vaccinia virus and murine encephalomyocarditis virus. among such species, seven are reported to be of traditional medicinal use no cytotoxicity was observed for most of the extracts up to the concentration of 500 μg/ml. fourteen (50%) of the 28 extracts assayed have disclosed antiviral activity with ec50 values in the range of 4.6+0.3 to 377.2+17.7 μg/ml. only two species, arrabidaea samydoides and callichlamys latifolia, have shown activity against all the three viruses. the extracts were chemically characterized by their tlc and hplc-dad profiles. mangiferin is the major constituent of a. samydoides but the isolated compound has been less active than the crude extract. this is the first report on the antiviral evaluation of the eighteen bignoniaceae species assayed.
Chemistry and Antiviral Activity of Arrabidaea pulchra (Bignoniaceae)
Geraldo Célio Brand?o,Erna G. Kroon,Danielle E.R. Souza,José D. Souza Filho,Alaíde Braga Oliveira
Molecules , 2013, DOI: 10.3390/molecules18089919
Abstract: The 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 LLCMK 2 and Vero cells and the Selectivity Indexes (SI) were calculated. The most potent effect was observed against DENV-2 (EC 50 46.8 ± 1.6 μg mL ?1; SI 2.7). For HSV-1 and VACV-WR EC 50 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.
NOGUEIRA, Maurício L.;OLIVEIRA, Adriana F.;ARAUJO, Janaína G.;GALLO, Márcio A.;FONSECA, Jo?o G. M.;BONJARDIM, Claudio A.;FERREIRA, Paulo C.P.;KROON, Erna G.;
Revista do Instituto de Medicina Tropical de S?o Paulo , 1998, DOI: 10.1590/S0036-46651998000500009
Abstract: herpetic infections are common complications in aids patients. the clinical features could be uncommon and antiviral chemotherapy is imperative. a rapid diagnosis could prevent incorrect approaches and treatment. the polymerase chain reaction is a rapid, specific and sensible method for dna amplification and diagnosis of infectious diseases, especially viral diseases. this approach has some advantages compared with conventional diagnostic procedures. recently we have reported a new pcr protocol to rapid diagnosis of herpetic infections with suppression of the dna extraction step. in this paper we present a case of herpetic whitlow with rapid diagnosis by hsv-1 specific polymerase chain reaction using the referred protocol.
A tetravalent dengue nanoparticle stimulates antibody production in mice
Elisangela F Silva, Mariana Orsi, ?ngela L Andrade, Rosana Z Domingues, Breno M Silva, Helena RC de Araújo, Paulo FP Pimenta, Michael S Diamond, Eliseu SO Rocha, Erna G Kroon, Luiz CC Malaquias, Luiz FL Coelho
Journal of Nanobiotechnology , 2012, DOI: 10.1186/1477-3155-10-13
Abstract: Here, we used a murine model to evaluate the IgG production after administration of inactivated DENV corresponding to all four serotypes adsorbed to bovine serum albumin nanoparticles. This formulation induced a production of anti-DENV IgG antibodies (p < 0.001). However, plaque reduction neutralization assays with the four DENV serotypes revealed that these antibodies have no neutralizing activity in the dilutions tested.Our results show that while the nanoparticle system induces humoral responses against DENV, further investigation with different DENV antigens will be required to improve immunogenicity, epitope specicity, and functional activity to make this platform a viable option for DENV vaccines.Dengue virus (DENV) is a major public health problem worldwide, especially in the tropical and subtropical areas with around 2.5 billion people living in areas at risk [1]. The disease is caused by a positive sense, single-stranded RNA virus that belongs to genus Flavivirus, family Flaviviridae. DENV is transmitted to humans primarily after a bite by an infected Aedes aegypti and Aedes albopictus mosquitoes. Infection with one of the DENV serotypes (DENV-1, -2, -3 and -4) causes a mild, self-limiting febrile illness called dengue fever (DF). However, after secondary infection, a small subset (~0.5%) develop the dengue hemorrhagic fever (DHF)/dengue shock syndrome (DSS), the severe form of the disease [2].While vaccines could potentially prevent DENV infection or disease in humans, none are currently licensed despite decades of intensive research [3]. To date, several approaches have been developed towards generating a tetravalent anti-DENV vaccine including live-attenuated strains, inactivated strains, subunit DNA or plasmid vaccines, and recombinant proteins [4]. Our group has begun vaccine studies using a unique platform, the nanoparticles. Biodegradable nanoparticles are currently used as drug carriers or as adjuvants for vaccines [5]. Polymeric nanoparticles with
Intracerebral infection with dengue-3 virus induces meningoencephalitis and behavioral changes that precede lethality in mice
Debora CG Amaral, Milene A Rachid, Marcia C Vilela, Roberta DL Campos, Gustavo P Ferreira, David H Rodrigues, Norinne Lacerda-Queiroz, Aline S Miranda, Vivian V Costa, Marco A Campos, Erna G Kroon, Mauro M Teixeira, Antonio L Teixeira
Journal of Neuroinflammation , 2011, DOI: 10.1186/1742-2094-8-23
Abstract: C57BL/6 mice received 4 × 103 PFU of DENV-3 by an intracranial route. We evaluated the trafficking of leukocytes in brain microvasculature using intravital microscopy, and evaluated chemokine and cytokine profiling by an ELISA test at 3 and 6 days post infection (p.i.). Furthermore, we determined myeloperoxidase activity and immune cell populations, and also performed histopathological analysis and immunostaining for the virus in brain tissue.All animals developed signs of encephalitis and died by day 8 p.i. Motor behavior and muscle tone and strength parameters declined at day 7 p.i. We observed increased leukocyte rolling and adhesion in brain microvasculature of infected mice at days 3 and 6 p.i. The infection was followed by significant increases in IFN-γ, TNF-α, CCL2, CCL5, CXCL1, and CXCL2. Histological analysis showed evidence of meningoencephalitis and reactive gliosis. Increased numbers of neutrophils, CD4+ and CD8+ T cells were detected in brain of infected animals, notably at day 6 p.i. Cells immunoreactive for anti-NS-3 were visualized throughout the brain.Intracerebral infection with non-adapted DENV-3 induces encephalitis and behavioral changes that precede lethality in mice.Dengue, one of the most important arboviral human diseases, is a serious cause of morbidity and mortality in tropical and subtropical regions of the world. Approximately 2.5 billion people are at risk of being infected by dengue virus [1]. The dengue virus (DENV) comprises four serotypes - DENV-1, DENV-2, DENV-3, and DENV-4, all of which appear to be present in 22 of the 27 states of Brazil [2-4].Although DENV has been considered a non-neurotropic virus in humans, some authors have described the presence of the virus in cerebrospinal fluid (CSF), and dengue antigens in brain tissue [5,6]. Moreover, infection has been associated with encephalitis, acute disseminated encephalomyelitis, neuropathies, and Guillain-Barré syndrome [6-8]. Therefore, dengue infection should be considered a
Nested-multiplex PCR detection of Orthopoxvirus and Parapoxvirus directly from exanthematic clinical samples
J?natas S Abrah?o, Larissa S Lima, Felipe L Assis, Pedro A Alves, André T Silva-Fernandes, Marcela MG Cota, Vanessa M Ferreira, Rafael K Campos, Carlos Mazur, Zélia IP Lobato, Giliane S Trindade, Erna G Kroon
Virology Journal , 2009, DOI: 10.1186/1743-422x-6-140
Abstract: The OPV/PPV nested-multiplex PCR was developed based on the evaluation and combination of published primer sets, and was applied to the detection of the target pathogens. The method showed high sensitivity, and the specificity was confirmed by amplicon sequencing. Exanthematic lesion samples collected during bovine vaccinia or contagious ecthyma outbreaks were submitted to OPV/PPV nested-multiplex PCR and confirmed its applicability.These results suggest that the presented multiplex PCR provides a highly robust and sensitive method to detect OPV and PPV directly from clinical samples. The method can be used for viral identification and monitoring, especially in areas where OPV and PPV co-circulate.Orthopoxvirus (OPV) and Parapoxvirus (PPV) consist of large, enveloped, linear double-stranded DNA viruses, and are classified as genera of the family Poxviridae [1]. Several species included in these genera are related with worldwide acute exanthematic disease in humans and domestic animals, which cause serious economic losses and impact public health [1,2]. There are three zoonotic OPV species known, Monkeypox virus (MPXV), Cowpox virus (CPXV) and Vaccinia virus (VACV), and their presence is associated with an increased number of outbreaks in Africa, Europe, South America and Asia [3-6]. Similarly, several zoonotic PPV infections have been noted, and are caused mainly by Bovine papular stomatitis virus (BPSV), Orf virus (ORFV) and Pseudocowpox virus (PSCV) [7,8]. Even though humans are susceptible to MPXV, CPXV, VACV, BPSV, ORFV and PSCV, domestic animals such as sheep, goats, cats, dogs and dairy cattle can be infected by some OPV and/or PPV since the host-range of these viruses is large and incompletely known [9]. OPV and PPV transmission is usually promoted by fomites or direct contact, and the infected humans play an important role in viral spread among domestic animals, especially during milking and other occupational livestock activities [1,9].Clinically, the exant
Detection and phylogenetic analysis of Orf virus from sheep in Brazil: a case report
J?natas S Abrah?o, Rafael K Campos, Giliane S Trindade, Maria IM Guedes, Zélia IP Lobato, Carlos Mazur, Paulo CP Ferreira, Cláudio A Bonjardim, Erna G Kroon
Virology Journal , 2009, DOI: 10.1186/1743-422x-6-47
Abstract: an outbreak of ovine contagious ecthyma in Midwest Brazil was investigated. The diagnosis was based on clinical examinations and molecular biology techniques. The molecular characterization of the virus was done using PCR amplification, cloning and DNA sequencing of the B2L gene. The phylogenetic analysis demonstrated a high degree of identity with ORFV strains, and the isolate was closest to the ORFV-India 82/04 isolate. Another Brazilian ORFV isolate, NE1, was sequenced for comparative analysis and also showed a high degree of identity with an Asian ORFV strain.Distinct ORFV strains are circulating in Brazil. This is the first report on the phylogenetic analysis of an ORFV in South America.Orf virus (ORFV), the prototype of the genus Parapoxvirus (PPV), is the etiological agent of contagious ecthyma, a severe exanthematic dermatitis that afflicts domestic and wild small ruminants [1]. The disease is usually characterized by highly infectious pustules on the lips, tongue and around the mouth. The transmission occurs by direct contact or via environmental contamination [2,3]. A decrease in host fitness is observed, since the lesions lead to the underfeeding of young lambs. Contagious ecthyma is a zoonosis, and the human disease consists of acute skin lesions, malaise and lymphadenopathy [4,5]. Immunodeficient people, however, can develop serious infections [6].In the last several years, several ORFV outbreaks have been occurred worldwide [7-11]. Although clinical diagnosis and electron microscopy have been used for viral identification, only PCR and genomic analyses can distinguish ORFV from other PPV species [12]. The PPV major membrane glycoprotein (B2L) gene has been used in the molecular characterization and phylogenetic analysis [8-11]. Although South American ORFV outbreaks have occurred and diagnosed, there are no South American ORFV B2L nucleotide sequences available [13]. Here we described the detection and partial sequencing of the B2L gene of a Brazilian
Acanthamoeba polyphaga mimivirus Stability in Environmental and Clinical Substrates: Implications for Virus Detection and Isolation
Fábio P. Dornas, Lorena C. F. Silva, Gabriel M. de Almeida, Rafael K. Campos, Paulo V. M. Boratto, Ana P. M. Franco-Luiz, Bernard La Scola, Paulo C. P. Ferreira, Erna G. Kroon, J?natas S. Abrah?o
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0087811
Abstract: Viruses are extremely diverse and abundant and are present in countless environments. Giant viruses of the Megavirales order have emerged as a fascinating research topic for virologists around the world. As evidence of their ubiquity and ecological impact, mimiviruses have been found in multiple environmental samples. However, isolation of these viruses from environmental samples is inefficient, mainly due to methodological limitations and lack of information regarding the interactions between viruses and substrates. In this work, we demonstrate the long-lasting stability of mimivirus in environmental (freshwater and saline water) and hospital (ventilator plastic device tube) substrates, showing the detection of infectious particles after more than 9 months. In addition, an enrichment protocol was implemented that remarkably increased mimivirus detection from all tested substrates, including field tests. Moreover, biological, morphological and genetic tests revealed that the enrichment protocol maintained mimivirus particle integrity. In conclusion, our work demonstrated the stability of APMV in samples of environmental and health interest and proposed a reliable and easy protocol to improve giant virus isolation. The data presented here can guide future giant virus detection and isolation studies.
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