210 resultados para Molecular design of polymers


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Molecular findings that confirmed the participation of ovine herpesvirus 2 (OVH-2) in the lesions that were consistent with those observed in malignant catarrhal fever of cattle are described. Three mixed-breed cattle from Rio Grande do Norte state demonstrated clinical manifestations that included mucopurulent nasal discharge, corneal opacity and motor incoordination. Routine necropsy examination demonstrated ulcerations and hemorrhage of the oral cavity, corneal opacity, and lymph node enlargement. Significant histopathological findings included widespread necrotizing vasculitis, non-suppurative meningoencephalitis, lymphocytic interstitial nephritis and hepatitis, and thrombosis. PCR assay performed on DNA extracted from kidney and mesenteric lymph node of one animal amplified a product of 423 base pairs corresponding to a target sequence within the ovine herpesvirus 2 (OVH-2) tegument protein gene. Direct sequencing of the PCR products, from extracted DNA of the kidney and mesenteric lymph node of one cow, amplified the partial nucleotide sequences (423 base pairs) of OVH-2 tegument protein gene. Blast analysis confirmed that these sequences have 98-100% identity with similar OVH-2 sequences deposited in GenBank. Phylogenetic analyses, based on the deduced amino acid sequences, demonstrated that the strain of OVH-2 circulating in ruminants from the Brazilian states of Rio Grande do Norte and Minas Gerais are similar to that identified in other geographical locations. These findings confirmed the active participation of OVH-2 in the classical manifestations of sheep associated malignant catarrhal fever.

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Neorickettsia risticii is the causative agent of Potomac Horse Fever, a severe febrile disease affecting horses, transmitted by trematodes species with a complex life cycle. A total of 30 insectivorous bats (Brazilian free-tailed bat Tadarida brasiliensis) were analyzed by PCR for presence of genus Anaplasma, Ehrlichia, Neorickettsia and Rickettsia. Three samples showed positive reactions for genus Anaplasma, Ehrlichia and Neorickettsia, and the sequences were 99.67% identical to Neorickettsia risticii. The role of bats in the life cycle of N. risticii has yet to be elucidated; however bats may be reservoirs for this bacterium. To our knowledge, this is the first evidence of N. risticii in Argentina.

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The rickettsia Anaplasma marginale is considered the main agent of bovine anaplasmosis. Due the nonspecific clinical signs of the anaplasmosis, the diagnosis of infection depends of laboratory confirmation. In recent years, molecular diagnostic methods have been used to detect A. marginale in cattle. However, the existence of a large number of assays of different sensitivity and cost makes the choice of an appropriate test difficult. In the present study, a real-time Polymerase Chain Reaction (PCR) based on the msp5 target gene was quantitatively assessed and compared to an end point PCR. Both reactions were subjected to sensitivity and specificity evaluation using plasmid DNA and samples from cattle experimentally infected with A. marginale. A comparative field trial of the tests was carried out using samples of cattle from a stable enzootic area for A. marginale. The real-time PCR showed a higher sensitivity than the end point PCR. This reaction (i.e. real-time PCR) was able to detect one copy of the msp5 gene in 100 ηg of plasmidial DNA, and more than 80% of its results were positive among experimentally infected animals seven days after infection. In addition, based on in silico analysis, the real-time PCR evaluated in the present study appears to be useful for the detection of A. ovis.

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Cryptococcosis is an infection that affects humans and animals, the etiology is attributed to Cryptococcus neoformans variety neoformans, C. neoformans var. grubii and Cryptococcus gattii. The infection is common in dogs and cats, causing respiratory, neurological, cutaneous and ocular infections. Aiming to better understand the epidemiology of cryptococcosis in animals in the region, this paper describe the occurrence and characterization of the Cryptococcus species involved in this illness in pet animals at Mato Grosso State, Brazil. Clinical samples of four cases, two in cats and two dogs, were submitted for pathological, microbiological and molecular analysis. Microscopically, in three cases, tissue sections stained with hematoxylin and eosin had absence to severe granulomatous reaction composed by histiocytes, multinucleated cells and lymphocytes infiltration. In one case, citological imprint analysis showed similar inflammatory mainly mononuclear and lymphocyte cells infiltration. All cases had variable amounts of intracellular and extracellular fungal structures compatible with Cryptococcus sp. on Periodic Acid-Schiff (PAS) stain. All clinical samples were positive for culture on Sabouraud Dextrose Agar (SDA) and morphologically classified as Cryptococcus sp. The isolates were PCR positive for C. gatti, being confirmed by sequencing technique. The findings characterize the molecular species involved in animal infections in the region, and may contribute to future studies of the epidemiology of C. gattii.

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Magellanic penguins (Spheniscus magellanicus) routinely migrate from their breeding colonies to Southern Brazil often contracting diseases during this migration, notably avian malaria, which has been already reported in Brazil and throughout the world. Detection of Plasmodium spp. in blood smears is the routine diagnostic method of avian malaria, however it has a low sensitivity rate when compared to molecular methods. Considering the negative impact of avian malaria on penguins, the aim of this study was to detect the presence of Plasmodium spp. in Magellanic penguins using Polymerase Chain Reaction (PCR) and by verifying clinical, hematological, and biochemical alterations in blood samples as well as to verify the likely prognosis in response to infection. Blood samples were obtained from 75 penguins to determine packed cell volume (PCV), red blood cell (RBC) and white blood cell (WBC) counts, mean corpuscular volume (MCV), uric acid, total protein, albumin, globulin and aspartate aminotransferase (AST) activity levels. Whole blood samples were used for PCR assays. Plasmodium spp. was detected in 32.0% of the specimens using PCR and in 29.3% using microscopic analyses. Anorexia, diarrhea and neurological disorders were more frequent in penguins with malaria and a significant weight difference between infected and non-infected penguins was detected. PCV and MCV rates showed no significant difference. RBC and WBC counts were lower in animals with avian malaria and leukopenia was present in some penguins. Basophil and lymphocyte counts were lower in infected penguins along with high monocyte counts. There was no significant difference in AST activities between infected and non-infected animals. There was a significant increase in uric acid values, however a decrease in albumin values was observed in infected penguins. Based on this study, we concluded that Plasmodium spp. occurs in Magellanic penguins of rehabilitation centers in Southeastern Brazil, compromising the weight of infected animals with clinical alterations appearing in severe cases of this disease. It was also noted that, although the hematological abnormalities presented by these animals may not have been conclusive, leukopenia, monocytosis and the decrease of basophils and lymphocytes revealed an unfavorable prognosis, and Plasmodium spp. infections may progress with elevated uric acid concentration and low albumin levels.

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Bovine meningoencephalitis caused by BHV-5, a double-stranded DNA enveloped virus that belongs to the family Herpesviridae and subfamily Alphaherpesvirinae, is an important differential diagnosis of central nervous diseases. The aim of this study was to describe the histological changes in the central nervous system of calves experimentally infected with BHV-5 and compare these changes with the PCR and IHC results. Formalin-fixed paraffin-embedded central nervous system samples from calves previously inoculated with BHV-5 were microscopically evaluated and tested using IHC and PCR. All the animals presented with nonsuppurative meningoencephalitis. From 18 evaluated areas of each calf, 32.41% and 35.19% were positive by IHC and PCR, respectively. The telencephalon presented more accentuated lesions and positive areas in the PCR than other encephalic areas and was the best sampling area for diagnostic purposes. Positive areas in the IHC and PCR were more injured than IHC and PCR negative areas. The animal with neurological signs showed more PCR- and IHC-positive areas than the other animals.

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AbstractMycobacterium avium subspecies paratuberculosis (MAP) can infect ruminants and remain subclinical for long periods within herds. The identification of organs that are more susceptible to infection and the evaluation of cytokine expression at the site of infection are important to understand the pathogenesis of MAP. In this study, the probability of detection of MAP-DNA and the expression of cytokines in organs of C57BL/6 mice infected intraperitoneally for 120 days were evaluated. Among the evaluated organs, the spleen (85%), colon (75%) and liver (60%) had the highest frequency of positivity. When compared these frequencies between organs, it has been found that the spleen had 1.54 times as likely to be positive in relation to the ileum, and 2.0 times more likely in relation to the Peyer's patches. In addition, at 60 days post-infection, the spleen and the liver were responsible for upregulation of IFN-γ , and the ileum by TNF-α and IL-4. The results indicate that the spleen is the best organ for evaluating an experimental infection by MAP, especially in the initial stages of the infection. Moreover, it showed that the spleen, liver and ileum have a direct role in the inflammatory response in experimental models.

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AbstractPorcine teschovirus (PTV), porcine sapelovirus (PSV), and enterovirus G (EV-G) are infectious agents specific to pig host species that are endemically spread worldwide. This study aimed to investigate the natural infection by these porcine enteric picornaviruses in wild boars (Sus scrofa scrofa) of Paraná state, Brazil, and to evaluate peccaries (Pecari tajacu and Tayassu pecari) as alternative host species for these viruses. Fecal samples (n=36) from asymptomatic wild boars (n=22) with ages ranging from 2 to 7 months old (young, n=14) and 2 to 4 years old (adult, n=8) and from peccaries (6 to 8 months old, n=14) were collected from a farm and a zoo, respectively, both located in Paraná state. Reverse transcription-polymerase chain reaction (RT-PCR) and nested-PCR (n-PCR) assays targeting the 5'non-translated region of the virus genome were used for screening the viruses. Porcine enteric picornaviruses were detected in 12 out of the 22 wild boar fecal samples. According to each of the viruses, EV-G was most frequently (11/22, 50%) detected, followed by PTV (10/22, 45.5%) and PSV (4/22, 18.2%). Regarding the age groups, young wild boars were more frequently (9/14, 64.3%) infected with PTV, PSV, and EV-G than adult animals (3/8, 37.4%). One n-PCR amplified product for each of the viruses was submitted to sequencing analysis and the nucleotide sequences were compared with the related viruses, which showed similarities varying from 97.7% to 100% for PTV, 92.4% to 96.2% for PSV, and 87.1% to 100% for EV-G. Peccaries tested negative for the viruses and in this study they did not represent infection reservoirs. This study is the first to report the molecular detection of PTV, PSV, and EV-G from captive wild boars in a South American country and the first to screen peccaries as alternative host species for porcine enteric picornavirus.

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Abstract: Rotaviruses are etiological agents of diarrhea both in humans and in several animal species. Data on avian Group D rotaviruses (RVD) are scarce, especially in Brazil. We detected RVD in 4 pools of intestinal contents of broilers, layer and broiler breeders out of a total of 111 pools from 8 Brazilian states, representing an occurrence of 3.6%, by a specific RVD RT-PCR targeting the VP6 gene. Phylogenetic tree confirmed that the Brazilian strains belong to group D and 3 of the sequences were identical in terms of amino acid whereas one showed 99.5% identity with the others. The sequences described in this study are similar to other sequences previously detected in Brazil, confirming the conserved nature of the VP6 protein.

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In this paper, the optimum design of 3R manipulators is formulated and solved by using an algebraic formulation of workspace boundary. A manipulator design can be approached as a problem of optimization, in which the objective functions are the size of the manipulator and workspace volume; and the constrains can be given as a prescribed workspace volume. The numerical solution of the optimization problem is investigated by using two different numerical techniques, namely, sequential quadratic programming and simulated annealing. Numerical examples illustrate a design procedure and show the efficiency of the proposed algorithms.

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Begomoviruses are whitefly-transmitted, single-stranded DNA viruses that are often associated with weed plants. The aim of this study was to further characterize the diversity of begomoviruses infecting weeds (mostly Sida spp.) in Brazil. Total DNA was extracted from weed samples collected in Viçosa (Minas Gerais state) and in some municipalities of Alagoas state in 2009 and 2010. Viral genomes were amplified by RCA, cloned and sequenced. A total of 26 DNA-A clones were obtained. Sequence analysis indicated the presence of 10 begomoviruses. All viral isolates from Blainvillea rhomboidea belonged to the same species, Blainvillea yellow spot virus (BlYSV ), thereby suggesting that BlYSV may be the only begomovirus present in this weed species. Four isolates represent new species, for which the following names are proposed: Sida yellow blotch virus (SiYBV), Sida yellow net virus (SiYNV), Sida mottle Alagoas virus (SiMoAV) and Sida yellow mosaic Alagoas virus (SiYMAV). Recombination events were detected among the SiYBV isolates and in the SiYNV isolate. These results constitute further evidence of the high species diversity of begomoviruses in Sida spp. However, the role of this weed species as a source of begomoviruses infecting crop plants remains to be determined.

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This study aimed to evaluate species level taxonomy and phylogenetic relationship among Thorea species in Brazil and other regions of the world using two molecular markers - RUBISCO large subunit plastid gene (rbcL) and nuclear small-subunit ribosomal DNA (SSU rDNA). Three samples of Thorea from Brazil (states of Mato Grosso do Sul and São Paulo) and one sample from Dominican Republic (DR) were sequenced. Analyses based on partial sequences of rbcL (1,282 bp) and complete sequences of SSU (1,752 bp) were essentially congruent and revealed that Thoreales formed a distinct monophyletic clade, which had two major branches with high support, representing the genera Thorea and Nemalionopsis. Thorea clade had four main branches with high support for all analyses, each one representing the species: 1) T. gaudichaudii C. Agardh from Asia (Japan and Philippines) - this clade occurred only in the rbcL analyses; 2) T. violacea Bory from Asia (Japan) and North America (U.S.A. and DR); 3) T. hispida (Thore) Desvaux from Europe (England) and Asia (Japan); 4) a distinct group with the three Brazilian samples (sequence identity: rbcL 97.2%, 1,246 bp; SSU 96.0-98.1%, 1,699-1,720 bp). The Brazilian samples clearly formed a monophyletic clade based on both molecular markers and was interpreted as a separate species, for which we resurrected the name T. bachmannii Pujals. Morphological and molecular evidences indicate that the Thoreales is well-resolved at ordinal and generic levels. In contrast, Thorea species recognized by molecular data require additional characters (e.g. reproductive and chromosome numbers) to allow consistent and reliable taxonomic circumscription aiming at a world revision based on molecular and morphological evidences.

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The a-globin major genes from diploid and tetraploid Odontophrynus americanus were studied using PCR-based technology. The cloned and sequenced amplified fragments were shown to contain most of the exon II sequences as well as the whole exon III sequence of the a-globin gene. Unexpectedly, intron 2 was entirely absent in the amplified fragments of both 2n and 4n origin. High conservation was observed among the obtained sequences when compared to corresponding sequences from human and Xenopus laevis origin. The possibility that these sequences might be pseudogenes is raised

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Machado-Joseph disease (MJD) is a form of autosomal dominant spinocerebellar ataxia first described in North-American patients originating from the Portuguese islands of the Azores. Clinically this disorder is characterized by late onset progressive ataxia with associated features, such as: ophthalmoplegia, pyramidal and extrapyramidal signs and distal muscular atrophies. The causative mutation is an expansion of a CAG repeat in the coding region of the MJD1 gene. We have identified 25 unrelated families segregating the MJD mutation during a large collaborative study of spinocerebellar ataxias in Brazil. In the present study a total of 62 family members were genotyped for the CAG repeat in the MJD1 gene, as well as 63 non-MJD individuals (126 normal chromosomes), used as normal controls. We observed a wide gap between the size range of the normal and expanded CAG repeats: the normal allele had from 12 to 33 CAGs (mean = 23 CAGs), whereas the expanded alleles ranged from 66 to 78 CAGs (mean = 71.5 CAGs). There were no differences in CAG tract length according to gender of affected individuals or transmitting parent. We observed a significant negative correlation between age at onset of the disease and length of the CAG tract in the expended allele (r = -0.6, P = 0.00006); however, the size of the expanded CAG repeat could explain only about 40% of the variability in age at onset (r2 = 0.4). There was instability of the expanded CAG tract during transmission from parent to offspring, both expansions and contractions were observed; however, there was an overall tendency for expansion, with a mean increase of +2.4 CAGs. The tendency for expansion appeared to the greater in paternal (mean increase of +3.5 CAGs) than in maternal transmissions (mean increase of +1.3 CAGs). Anticipation was observed in all transmissions in which ages at onset for parent and offspring were known; however, anticipation was not always associated with an increase in the expanded CAG repeat length. Our results indicate that the molecular diagnosis of MJD can be confirmed or excluded in all suspected individuals, since alleles of intermediary size were not observed.