Preparation and characterization of monomodal grapevine virus a capsid protein

Grapevine virus A (GVA), a flexible filament of approximately 800 nm in length is composed of capsid subunits that spontaneously assembles around a positive sense genomic RNA. In addition to encapsidation, plant viruses capsid proteins (CPs) participate in other processes throughout infection and GVA CP is involved in cell-to-cell translocation of the virus. A protocol was developed to obtain low-molecular weight GVA-CP that is not prone to aggregation and spontaneous assembly and this was characterized by circular dichroism and dynamic light scattering. These results indicate the suitably of GVA-CP for X-ray crystallographic and NMR studies that should lead to the elucidation of the first three-dimensional structure of a flexible filamentous virus from the Betaflexiviridae family.

Specific detection of Lettuce mosaic virus isolates belonging to the Most type

Lettuce mosaic virus (LMV)-Most isolates can infect and are seed-borne in cultivars containing the mol gene. A reverse transcription and polymerase chain reaction (RT-PCR)-based test was developed for the specific detection of LMV-Most isolates. Based on the complete genome sequences of three LMV isolates belonging respectively to the Most type, the Common type and neither of these two types, three different assays were compared: (i) presence of a diagnostic restriction site in the region of the genome encoding the variable N-terminus of the capsid protein, in the 3' end of the genome, (ii) RT-PCR using primers designed to amplify a cDNA corresponding to a portion of the P1 coding region, in the 5' end of the genome and (iii) RT-PCR using primers designed to amplify a central region of the genome. The assays were performed against a collection of 21 isolates from different geographical origins and representing the molecular variability of LMV. RT-PCR of the central region of the genome was preferred because its results are expected to be less affected by natural recombination between LMV isolates, and it allows sensitive detection of LMV-Most in situations of single as well as mixed contamination. (C) 2004 Elsevier B.V. All rights reserved.

Prevalence of Lettuce mosaic virus - common strain on three lettuce producing areas from São Paulo State

O LMV ocorre em todo o mundo e é considerado um dos patógenos mais importantes para a cultura da alface. de acordo com a habilidade em contornar os genes de resistência mo1¹ e mo1² encontrados em alface, os isolados de LMV podem ser dividos em dois sub-grupos: LMV-Most, capazes de contornar a resistência propiciada por estes genes e de serem transmitidos pela semente nestas cutivares, e LMV-Common, que não são capazes de causar sintomas nestes cultivares, além de serem transmitidos pela semente somente em cultivares suscetíveis. Para avaliar a ocorrência destes dois tipos de isolados de LMV foram coletadas, durante 2002-2005, amostras de alface com sintomas de mosaico em áreas de produção de alface comercial das regiões de Campinas, Mogi das Cruzes e Bauru no estado de São Paulo. O RNA total foi utilizado para detecção por RT-PCR utilizando-se oligonucleotídeos universais para LMV que amplificam a porção N-terminal variável da capa protéica, localizada no terminal 3´do genoma. As amostras positivas foram analisadas por um segundo primer que amplifica um fragmento da região central (CI-VPg) do genoma viral. Um total de 1362 amostras foram avaliadas, tendo sido detectado o LMV em 504 amostras (37,29%). O LMV-Common prevaleceu em variedades suscetíveis (77,3%). O LMV-Most foi encontrado frequentemente associado a variedades portadoras do gene de tolerância mo1¹. Apesar da existência dos LMV-Most capazes de contornar a resistência em alface, estes não predominam em nossa condições.

Molecular characterization of two Brazilian isolates of Lettuce mosaic virus with distinct biological properties

Efetuou-se a clonagem e seqüenciamento do gene que codifica a proteína capsidial de dois isolados do vírus do mosaico da alface (Lettuce mosaic virus, LMV) provenientes do estado de São Paulo, previamente caracterizados como pertencentes aos patótipos II (AF198, incapaz de infetar cultivares com os genes de resistência mo1¹ ou mo1²) e IV (AF199, capaz de quebrar a resistência propiciada pelos genes mo1¹ e mo1²), com base na virulência em cultivares diferenciadoras. Análise comparativa das seqüências de nucleotídeos de isolados provenientes da Europa, América do Norte, Oriente Médio e os dois isolados brasileiros não permitiu sua separação em estirpes, pois as porcentagens de homologia foram sempre superiores a 95%. Entretanto, análise filogenética dos isolados sugere uma origem comum entre o isolado AF-198 e os isolados LMV-R e LMV-0 (patótipo II, provenientes dos Estados Unidos e da França, respectivamente). O isolado AF199 apresentou uma alta homologia de seqüência com os isolados LMV-Aud e LMV-13, ambos provenientes da França. Esses isolados também são relacionados a isolados provenientes do Chile, embora uma origem comum não seja proposta. Eventos independentes de mutação podem estar ocorrendo em diferentes partes do mundo, propiciando o surgimento de novas estirpes de LMV capazes de quebrar a resistência conferida pelos genes mo1¹ e mo1².

Detection of turkey astrovirus in young poults affected with poult enteritis complex in Brazil

Reverse transcription polymerase chain reaction (RT-PCR) of turkey astrovirus (TAstV) capsid and polymerase genes was applied to the bursa of Fabricius (BF), thymus (TH), spleen (SP) and cloacal swabs (CS) of young poults with "Poult enteritis complex" (PEC). The histological lesions included atrophy, lymphoid depletion, cellular infiltration and necrosis of the BF, TH and SP, respectively. The RT-PCR reactions were positive for the polymerase gene of TAstV-2 in all 100 CSs, 7 out of 10 of BFs and 10 out of 20 THs and SPs, respectively. Five out of 10 THs and SPs samples, considered to be negative by RT-PCR, were positive when specific primers designed for the TAstV-2 capsid gene were applied. This is the first description of turkey astrovirus infection presenting PEC in Latin America.

Detection of porcine circovirus genotypes 2a and 2b in aborted foetuses from infected swine herds in the State of São Paulo, Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Genetic variability of porcine parvovirus isolates revealed by analysis of partial sequences of the structural coding gene VP2

The 3'-terminal 853 nt (and the putative 283 aa) sequence of the VP2-encoding gene from 29 field strains of porcine parvovirus (PPV) were determined and compared both to each other and with other published sequences. Sequences were examined using maximum-parsimony and statistical analyses for nucleotide diversity and sequence variability. Among the nucleotide sequences of the PPV field strains, 26 polymorphic sites were encountered; 22 polymorphic sites were detected in the putative amino acid sequence. Mapping polymorphic sites of protein data onto the three-dimensional (3D) structure of PPV VP2 revealed that almost all substitutions were located on the external surface of the viral capsid. Mapping amino acid substitutions to the alignment between PPV VP2 sequences and the 3D structure of canine parvovirus (CPV) capsid, many PPV substitutions were observed to map to regions of recognized antigenicity and/or to contain phenotypically important residues for CPV and other parvoviruses. In spite of the high sequence similarity, genetic analysis has shown the existence of at least two virus lineages among the samples. In conclusion, these results highlight the need for close surveillance on PPV genetic drift, with an assessment of its potential ability to modify the antigenic make-up of the virus.

Subcellular localization of the coat protein in tobacco cells infected by cucumber mosaic virus isolated from Catharanthus roseus

Electron microscopy and immunolabelling with antiserum specific to cucumber mosaic virus coat protein were used to examine tobacco leaf cells infected by cucumber mosaic virus isolated from Catharanthus roseus (CMV-Cr). Crystalline and amorphous inclusions in the vacuoles were the most obvious cytological modifications seen. Immunogold labelling indicated that the crystalline inclusion was made up of virus particles and amorphous inclusions contained coat protein. Rows of CMV-Cr particles were found between membranes of dictyosomes, but membranous bodies and tonoplast-associated vesicles were not evident. Virus particles and/or free coat protein were easily detected in the cytoplasm by immunolabelling. No gold labelling was found within nuclei, chloroplasts and mitochondria.

Papilomavirus Humano (HPV) - Um estudo de revisao

Human Papillomaviruses (HPVs) are epitheliotropic viruses, that induce benign and malignant lesions on several body sites. It's a small circular DNA virus, non-enveloped and 75 types have been identified. Frequently HPV 6, 11 (benign lesions) and 16, 18 (malignant lesions) are occurred on mucosa. The infection takes place at the basal layer cells with microlesions, when the virus enters into the cells and looses the capsid. The benign HPV types is associated to cell's genome in epissomal way. In malignant lesions, it integrates into the cell's DNA. HPV viruses are sexually transmitted and responsable for malignant cell transformation. Thus this viruses have an extremely epidemiologic importance. This paper reports a HPV review study about: epidemiology, diagnostic methods and treatment to papillomavirus infection.

Papilomavírus humano (HPV) em lesões benignas e malignas de mucosa oral pelos métodos de imuno-histoquímica e hibridização in situ

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Phylogenetic and structural studies of a novel equine papillomavirus identified from aural plaques

Papillomaviruses (PVs) infect a wide range of animal species and show great genetic diversity. To date, excluding equine sarcoids, only three species of PVs were identified associated with lesions in horses: Equus caballus papillomavirus 1 (EcPV1-cutaneous), EcPV2 (genital) and EcPV3 (aural plaques). In this study, we identified a novel equine PV from aural plaques, which we designated EcPV4. Cutaneous samples from horses with lesions that were microscopically diagnosed as aural plaques were subjected to DNA extraction, amplification and sequencing. Rolling circle amplification and inverse PCR with specific primers confirmed the presence of an approximately 8. kb circular genome. The full-length EcPV4 L1 major capsid protein sequence has 1488 nucleotides (495 amino acids). EcPV4 had a sequence identity of only 53.3%, 60.2% and 51.7% when compared with the published sequences for EcPV1, EcPV2 and EcPV3, respectively. A Bayesian phylogenetic analysis indicated that EcPV4 clusters with EcPV2, but not with EcPV1 and EcPV3. Using the current PV classification system that is based on the nucleotide sequence of L1, we could not define the genus of the newly identified virus. Therefore, a structural analysis of the L1 protein was carried out to aid in this classification because EcPV4 cause lesion similar to the lesion caused by EcPV3. A comparison of the superficial loops demonstrated a distinct amino acid conservation pattern between EcPV4/EcPV2 and EcPV4/EcPV3. These results demonstrate the presence of a new equine PV species and that structural studies could be useful in the classification of PVs. © 2012 Elsevier B.V.

Co-infecção por vírus dengue, sorotipos 1 e 4, em paciente de cidade de porte médio no Brasil

The natural co-infection with dengue virus can occur in highly endemic areas where different serotypes have been observed for many years. We report one case of DENV-1/DENV-4 co-infection in human serum detected by molecular tests. Phylogenetic analysis of the sequences obtained indicated the presence of genotype V and II for DENV-1 and DENV-4, respectively.

Proteína capsidial do Rupestris stem pitting-associated vírus: seqüenciamento do gene, expressão em Escherichia coli, purificação e produção de anti-soro policlonal

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Caracterização de allexivirus em alho nas regiões sul, sudeste e centro-oeste brasileiro e análise da sanidade vegetal do alho obtido por cultura de meristema e termoterapia na FCA/UNESP

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Variabilidade de potyvirus infectando Capsicum spp. no estado de São Paulo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)