315 resultados para genotypes characterization

em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo (BDPI/USP)


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Background: The Brazilian population is mainly descendant from European colonizers, Africans and Native Americans. Some Afro-descendants lived in small isolated communities since the slavery period. The epidemiological status of HBV infection in Quilombos communities from northeast of Brazil remains unknown. The aim of this study was to characterize the HBV genotypes circulating inside a Quilombo isolated community from Maranhao State, Brazil. Methods: Seventy-two samples from Frechal Quilombo community at Maranhao were collected. All serum samples were screened by enzyme-linked immunosorbent assays for the presence of hepatitis B surface antigen ( HBsAg). HBsAg positive samples were submitted to DNA extraction and a fragment of 1306 bp partially comprising HBsAg and polymerase coding regions (S/POL) was amplified by nested PCR and its nucleotide sequence was determined. Viral isolates were genotyped by phylogenetic analysis using reference sequences from each genotype obtained from GenBank (n = 320). Sequences were aligned using Muscle software and edited in the SE-AL software. Bayesian phylogenetic analyses were conducted using Markov Chain Monte Carlo (MCMC) method to obtain the MCC tree using BEAST v.1.5.3. Results: Of the 72 individuals, 9 (12.5%) were HBsAg-positive and 4 of them were successfully sequenced for the 1306 bp fragment. All these samples were genotype A1 and grouped together with other sequences reported from Brazil. Conclusions: The present study represents the first report on the HBV genotypes characterization of this community in the Maranhao state in Brazil where a high HBsAg frequency was found. In this study, we reported a high frequency of HBV infection and the exclusive presence of subgenotype A1 in an Afro-descendent community in the Maranhao State, Brazil.

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Background: Hepatitis B virus (HBV) can be classified into nine genotypes (A-I) defined by sequence divergence of more than 8% based on the complete genome. This study aims to identify the genotypic distribution of HBV in 40 HBsAg-positive patients from Rondonia, Brazil. A fragment of 1306 bp partially comprising surface and polymerase overlapping genes was amplified by PCR. Amplified DNA was purified and sequenced. Amplified DNA was purified and sequenced on an ABI PRISM (R) 377 Automatic Sequencer (Applied Biosystems, Foster City, CA, USA). The obtained sequences were aligned with reference sequences obtained from the GenBank using Clustal X software and then edited with Se-Al software. Phylogenetic analyses were conducted by the Markov Chain Monte Carlo (MCMC) approach using BEAST v.1.5.3. Results: The subgenotypes distribution was A1 (37.1%), D3 (22.8%), F2a (20.0%), D4 (17.1%) and D2 (2.8%). Conclusions: These results for the first HBV genotypic characterization in Rondonia state are consistent with other studies in Brazil, showing the presence of several HBV genotypes that reflects the mixed origin of the population, involving descendants from Native Americans, Europeans, and Africans.

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The Canchim (5/8 Charolais + 3/8 Zebu) beef cattle breed was developed at Southeast-Embrapa Cattle to take advantage of hybrid vigor and to combine the higher growth rate and beef quality of Charolais with tropical adaptations of Zebu. The development of three lineages (old, new, and crossbred) has increased its genetic basis. The genotypic origin (Bos taurus or Bos indicus) of the mitochondrial DNA (mtDNA) of the Canchim breed was unknown. We characterized the mtDNA genotype of this founder herd by allele-specific polymerase chain reaction. The 173 founder Zebu females (62 Indubrasil, 3 Guzerat, and 108 Nellore) and their 6749 offspring were identified. The frequency of B. indicus mtDNA ranged from 1.15 to 2.05% among the descendants (N = 6404) of each maternal line with available DNA, and among animals that were alive (N = 689) in December 2007 among the three lineages. Though mtDNA characterization can be used to direct animal selection, the low frequency of B. indicus mtDNA impairs the evaluation of its effects on production traits in these animals. The high prevalence of B. taurus mtDNA in Canchim proves that the founder Zebu females from the Indubrasil, Guzerat and Nellore breeds were obtained from crosses of Zebu sires with local B. taurus dams.

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Hepatitis B is a worldwide health problem affecting about 2 billion people and more than 350 million are chronic carriers of the virus. Nine HBV genotypes (A to I) have been described. The geographical distribution of HBV genotypes is not completely understood due to the limited number of samples from some parts of the world. One such example is Colombia, in which few studies have described the HBV genotypes. In this study, we characterized HBV genotypes in 143 HBsAg-positive volunteer blood donors from Colombia. A fragment of 1306 bp partially comprising HBsAg and the DNA polymerase coding regions (S/POL) was amplified and sequenced. Bayesian phylogenetic analyses were conducted using the Markov Chain Monte Carlo (MCMC) approach to obtain the maximum clade credibility (MCC) tree using BEAST v.1.5.3. Of all samples, 68 were positive and 52 were successfully sequenced. Genotype F was the most prevalent in this population (77%) - subgenotypes F3 (75%) and Fib (2%). Genotype G (7.7%) and subgenotype A2 (15.3%) were also found. Genotype G sequence analysis suggests distinct introductions of this genotype in the country. Furthermore, we estimated the time of the most recent common ancestor (TMRCA) for each HBV/F subgenotype and also for Colombian F3 sequences using two different datasets: (i) 77 sequences comprising 1306 bp of S/POL region and (ii) 283 sequences comprising 681 bp of S/POL region. We also used two other previously estimated evolutionary rates: (i) 2.60 x 10(-4) s/s/y and (ii) 1.5 x 10(-5) s/s/y. Here we report the HBV genotypes circulating in Colombia and estimated the TMRCA for the four different subgenotypes of genotype F. (C) 2010 Elsevier B.V. All rights reserved.

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Hepatitis C virus (HCV) is a frequent cause of acute and chronic hepatitis and a leading cause for cirrhosis of the liver and hepatocellular carcinoma. HCV is classified in six major genotypes and more than 70 subtypes. In Colombian blood banks, serum samples were tested for anti-HCV antibodies using a third-generation ELISA. The aim of this study was to characterize the viral sequences in plasma of 184 volunteer blood donors who attended the ""Banco Nacional de Sangre de la Cruz Roja Colombiana,`` Bogota, Colombia. Three different HCV genomic regions were amplified by nested PCR. The first of these was a segment of 180 bp of the 5`UTR region to confirm the previous diagnosis by ELISA. From those that were positive to the 5`UTR region, two further segments were amplified for genotyping and subtyping by phylogenetic analysis: a segment of 380 bp from the NS5B region; and a segment of 391 bp from the E1 region. The distribution of HCV subtypes was: 1b (82.8%), 1a (5.7%), 2a (5.7%), 2b (2.8%), and 3a (2.8%). By applying Bayesian Markov chain Monte Carlo simulation, it was estimated that HCV-1b was introduced into Bogota around 1950. Also, this subtype spread at an exponential rate between about 1970 to about 1990, after which transmission of HCV was reduced by anti-HCV testing of this population. Among Colombian blood donors, HCV genotype 1b is the most frequent genotype, especially in large urban conglomerates such as Bogota, as is the case in other South American countries. J. Med. Virol. 82: 1889-1898, 2010. (C) 2010 Wiley-Liss, Inc.

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Trypanosoma (Megatrypanum) theileri from cattle and trypanosomes of other artiodactyls form a clade of closely related species in analyses using ribosomal sequences. Analysis of polymorphic sequences of a larger number of trypanosomes from broader geographical origins is required to evaluate the Clustering of isolates as suggested by previous studies. Here, we determined the sequences of the spliced leader (SL) genes of 21 isolates from cattle and 2 from water buffalo from distant regions of Brazil. Analysis of SL gene repeats revealed that the 5S rRNA gene is inserted within the intergenic region. Phylogeographical patterns inferred using SL sequences showed at least 5 major genotypes of T. theileri distributed in 2 strongly divergent lineages. Lineage TthI comprises genotypes IA and IB from buffalo and cattle, respectively, from the Southeast and Central regions, whereas genotype IC is restricted to cattle from the Southern region. Lineage Tth II includes cattle genotypes IIA, which is restricted to the North and Northeast, and IIB, found in the Centre, West, North and Northeast. PCR-RFLP of SL genes revealed valuable markers for genotyping T. theileri. The results of this study emphasize the genetic complexity and corroborate the geographical structuring of T. theileri genotypes found in cattle.

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Dengue viruses (DENV) serotypes 1, 2, and 3 have been causing yearly outbreaks in Brazil. In this study, we report the reintroduction of DENV2 in the coast of Sao Paulo State. Partial envelope viral genes were sequenced from eighteen patients with dengue fever during the 2010 epidemic. Phylogenetic analysis showed this strain belongs to the American/Asian genotype and was closely related to the virus that circulated in Rio de Janeiro in 2007 and 2008. The phylogeny also showed no clustering by clinical presentation, suggesting that the disease severity could not be explained by distinct variants or genotypes. The time of the most recent common ancestor of American/Asian genotype and the Sao Paulo and Rio de Janeiro (SP/RJ) monophyletic cluster was estimated to be around 40 and 10 years, respectively. Since this virus was first identified in Brazil in 2007, we suggest that it was already circulating in the country before causing the first documented outbreak. This is the first description of the 2010 outbreak in the State of Sao Paulo, Brazil, and should contribute to efforts to control and monitor the spread of DENVs in endemic areas.

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Chagas disease caused by Trypanosoma cruzi is a complex disease that is endemic and an important problem in public health in Latin America. The T. cruzi parasite is classified into six discrete taxonomic units (DTUs) based on the recently proposed nomenclature (TcI, TcII, TcIII, TcIV, TcV and TcVI). The discovery of genetic variability within TcI showed the presence of five genotypes (Ia, Ib, Ic, Id and Ie) related to the transmission cycle of Chagas disease. In Colombia, TcI is more prevalent but TcII has also been reported, as has mixed infection by both TcI and TcII in the same Chagasic patient. The objectives of this study were to determine the T. cruzi DTUs that are circulating in Colombian chronic Chagasic patients and to obtain more information about the molecular epidemiology of Chagas disease in Colombia. We also assessed the presence of electrocardiographic, radiologic and echocardiographic abnormalities with the purpose of correlating T. cruzi genetic variability and cardiac disease. Molecular characterization was performed in Colombian adult chronic Chagasic patients based on the intergenic region of the mini-exon gene, the 24S alpha and 18S regions of rDNA and the variable region of satellite DNA, whereby the presence of T. cruzi I, II, III and IV was detected. In our population, mixed infections also occurred, with TcI-TcII, TcI-TcIII and TcI-TcIV, as well as the existence of the TcI genotypes showing the presence of genotypes Ia and Id. Patients infected with TcI demonstrated a higher prevalence of cardiac alterations than those infected with TcII. These results corroborate the predominance of TcI in Colombia and show the first report of TcIII and TcIV in Colombian Chagasic patients. Findings also indicate that Chagas cardiomyopathy manifestations are more correlated with TcI than with TcII in Colombia.

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Castor (Ricinus communis L.) is an important oleaginous plant from both economic and social points of view. The seeds contain an oil with excellent properties for industrial uses. This paper presents the main results of a study aiming to develop microsatellite markers for castor. Twelve new polymorphic microsatellite markers were isolated and characterized in 38 genotypes accessions from the castor germplasm of the Brazilian Agricultural Research Company (EMBRAPA). Knowledge on the genetic diversity of castor can be used to gain a better understanding on genetic diversity conservation, and germplasm management, guiding breeding programs and conservation strategies.

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Respiratory syncytial virus (RSV) is recognized as the leading cause of nosocomial respiratory infection among hematopoietic stem cell transplant (HSCT) recipients, causing considerable morbidity and mortality. RSV is easily transmitted by contact with contaminated surfaces, and in HSCT units, more than 50% of RSV infections have been characterized as of nosocomial origin. From April 2001 to October 2002, RSV was identified by direct immunofluorescent assay in 42 symptomatic HSCT recipients. Seven RSV strains from 2001 and 12 RSV strains from 2002 were sequenced. RNA extraction, cDNA synthesis, and seminested polymerase chain reaction (PCR) with primers complementary to RSV genes G and F were pet-formed. PCR products were analyzed by nucleotide sequencing of the C-terminal region of gene G for typing (in group A or B). Of the 7 strains analyzed in 2001, only 2 belonged to group B; the other 5 belonged to group A. Of these 7 strains, 3 were identical and were from recipients receiving outpatient care. In 2002, of the 12 strains analyzed, 3 belonged to group A and the other 9 belonged to group B. Of these 9 strains, 7 were genetically identical and were also from recipients receiving outpatient care. Therefore, multiple strains of RSV cocirculated in the hematopoietic stem cell transplant units (ward and outpatient units) between 2001 and 2002. Nosocomial transmission was more likely to occur at the HSCT outpatient unit than in the HSCT ward. Infection control practices should also be implemented in the outpatient setting.

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Recent studies indicated that Toxoplasma gondii isolates of many domestic animal hosts from Brazil are genetically and biologically different from those in USA and Europe. Despite of high pathogenicity of this parasite to small ruminants, the epidemiology and genetic diversity of T. gondii in these animals are not well understood in Brazil. In this study, a total of 28 T. gondii samples (16 isolates from sheep in Sao Paulo state, and 12 isolates from goats in the states of Sao Paulo and Rio Grande do Norte) were genotyped using genetic markers SAG1, SAG2, SAG3, BTUB, CRAG, c22-8, c29-2, L358, PK1, Apico and CS3. Eleven genotypes were identified from these T. gondii isolates. Eight isolates (4 from sheep and 4 from goats) were grouped into the common clonal type Brl lineage. One sheep isolate was grouped to the type BrIII lineage. Five isolates grouped to three previously identified genotypes in Brazil, and 13 isolates grouped to six novel genotypes. Mixed genotype was found in one isolate from goat in Sao Paulo. No classical clonal Type I. II or III isolates were found, confirming previous reports that these clonal lineages are rare in Brazil. The allele types at the CS3 locus are strongly linked to mouse virulence of the parasite. The results of this study indicate that even though a large number of T. gondii genotypes have been identified from a variety of animal hosts in Brazil, high percentage of new genotypes are continuously identified from different animal species, suggesting extremely high diversity of T. gondii in the population. (C) 2010 Elsevier B.V. All rights reserved.

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The aim of this study was to determine the prevalence of Cryptosporidium species and genotypes in birds kept in captivity in Brazil. A total of 966 samples from 18 families of birds was collected and stored in 5% potassium dichromate solution at 4 degrees C until processing. Oocysts were purified in Sheather sugar solution following extraction of genomic DNA. Molecular analyses were performed using nested-PCR for amplification of fragments of the 18S subunit of rRNA gene and of the actin gene. Amplification of Cryptosporidium DNA fragments was obtained in 47 (4.86%) samples. Sequencing of amplified fragments and phylogenetic analyses allowed the identification of Cryptosporidium baileyi in a black vulture (Coragyps atratus), a domestic chicken (Gallus gallus domesticus) and a saffron finch (Sicalis flaveola); Cryptosporidium galli in canaries (Serinus canaria), a cockatiel (Nymphicus hollandicus) and lesser seed-finches (Oryzoborus angolensis); Cryptosporidium meleagridis in a domestic chicken (G. g. domesticus); Cryptosporidium parvum in a cockatiel (N. hollandicus); Cryptosporidium avian genotype I in a canary (S. canaria) and an Indian peafowl (Pavo cristatus); Cryptosporidium avian genotype II in ostriches (Struthio camelus) and Cryptosporidium avian genotype III in a cockatiel (N. hollandicurs) and a peach-faced lovebird (Agapornis roseicolis). (C) 2009 Elsevier B.V. All rights reserved.

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Background: Human erythrovirus B 19, endemic in the Amazon region since 1990, is associated with a wide spectrum of clinical presentations. Objectives: To assess the prevalence of erythrovirus B 19 infection and the relative frequency of erythrovirus B 19 genotypes in patients in the Amazon region with various clinical presentations. Study design: A total of 487 clinical samples obtained from patients with symptoms suggestive of erythrovirus infection were tested using specific IgM and IgG antibody assays (ELISA) and PCR for viral DNA detection. Partial VP1 and VP2 regions were sequenced and genotyped by phylogenetic reconstruction. Results: B 19 DNA was detected in 117 (24%) of 487 samples. Of these, 106 (91%) isolates were genotype I and II (9%) were genotype 3. No genotype 2 was found. Genotype I had three clusters (A1, A2 and 13) and all genotype 3 sequences were subtype 3b. All patients with hernatological disorders within cluster B of genotype I were infected by the sarne B 19 lineage, suggesting that this lineage of B 19 may have been transmitted via transfusion of blood products. Conclusion: We reported two genotypes, I and 3b, with three genotype I clusters co-circulating in the Amazon region during the past 10 years. (C) 2008 Elsevier B.V. All rights reserved.

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We characterized sequences from genes encoding cathepsin L-like (CatL-like) cysteine proteases from African and South American isolates of Trypanosoma vivax and T. vivax-like organisms, and evaluated their suitability as genetic markers for population structure analysis and diagnosis. Phylogenetic analysis of sequences corresponding to CatL-like catalytic domains revealed substantial polymorphism, and clades of sequences (TviCatL1-9) were separated by large genetic distances. TviCatL1-4 sequences were from cattle isolates from West Africa (Nigeria and Burkina Faso) and South America (Brazil and Venezuela), which belonged to the same T. vivax genotype. T. vivax-like genotypes from East Africa showed divergent sequences, including TviCatL5-7 for isolates from Mozambique and TviCatL8-9 for an isolate from Kenya. Phylogenetic analysis of CatL-like gene data supported the relationships among trypanosome species reflected in the phylogenies based on the analysis of small subunit (SSU) of ribosomal RNA gene sequence data. The discovery of different CatL-like sequences for each genotype, defined previously by ribosomal DNA data, indicate that these sequences provide useful targets for epidemiological and population genetic studies. Regions in CatL-like sequences shared by all T. vivax genotypes but not by other trypanosomes allowed the establishment of a specific and sensitive diagnostic PCR for epidemiological studies in South America and Africa. (C) 2008 Elsevier Ltd. All rights reserved.

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Background: JC virus (JCV), the causative agent of progressive multifocal leukoencephalopathy (PML), is classified in 8 different genotypes. Previous reports have suggested a positive association between specific genotypes and PML. Objective: To compare genotypes and adaptive mutations of JCV strains from Brazilian AIDS patients with and without PML. Study design: The VP1 region of JCV was amplified by polymerase chain reaction from cerebrospinal fluid samples from 51 patients with PML and from urine samples of 47 patients with AIDS without central nervous system disease. Genotyping was done by phylogenetic analysis. Amino acid replacement and selection pressures were also investigated. Results: JCV genotype frequency distributions showed that genotypes 2 (32.7%), 1 (26.5%) and 3 (23.5%) were the most prevalent. Genotype 1 had a positive association (p < 0.0001) and genotype 3 showed an inverse association (p < 0.001) with PML. A previously undescribed point mutation at residue 91 (L/I or L/V) and (L/P), non-genotype-associated, was found in 5/49 (10.2%) and 2/47 (4.3%) JCV sequences from PML and non-PML patients, respectively. This mutation was under positive selection only in PML patients. A previously described substitution of T-A in position 128 showed a significant difference between PML and non-PML cases (70% versus 16%, respectively, p < 0.0005). Conclusion: In Brazilian patients with AIDS, JCV genotype 1 showed a strong association with PML (p < 0.0001) and JCV genotype 3 showed an inverse association with PML. The possible association of aminoacids substitution in residues 91 and 128 with PML in patients with AIDS must be further investigated. (C) 2010 Elsevier B.V. All rights reserved.