Epstein-Barr virus (EBV) nuclear antigen (EBNA)-4 mutation in EBV-associated malignancies in three different populations

Different ethnic groups with a high human leukocyte antigen (HLA)-A11 prevalence have been shown to experience a high rate of Epstein-Barr virus (EBV) infection, EBV-associated malignancies, and Epstein-Barr nuclear antigen (EBNA)-4 mutations. The epitopes 393-408 and 416-424 of EBNA-4 are major antigenic epitopes that elicit an HLA-A11 cytotoxic T lymphocyte (CTL) response to EBV infection. Mutations selectively involving one or more nucleotide residues in these epitopes affect the antigenicity of EBNA-4, because the mutant EBV strains are not recognized by the HLA-A11-restricted CTLs. To investigate these mutations in common EBV-associated malignancies occurring in different populations, we studied the mutation rate of epitopes 393-408 and 416-424 of EBNA-4 in 25 cases of EBV-associated Hodgkin's disease (HD), nine cases of AIDS-related non-Hodgkin's lymphoma, and 37 cases of EBV-associated gastric carcinoma (GC) from the United States, Brazil, and Japan. We found one or more mutations in these two epitopes in 50% (6/12) of United States HD, 15% (2/13) of Brazilian HD, 50% (6/12) United States GC and 28% (7/25) Japanese GC, and 22% (2/9) of United States AIDS-lymphoma. Similar mutations were found in 30% (3/10) of United States reactive, 0% (0/6) of Brazilian reactive, and 25% (2/8) Japanese reactive tissues. The most frequent amino acid substitutions were virtually identical to those seen in previously reported isolates from EBV-associated nasopharyngeal carcinomas and Burkitt's lymphomas occurring in high prevalence HLA-A11 regions. However, only 2/28 (7%) mutations occurred in HLA-A11-positive patients. Our studies suggest that: 1) EBNA-4 mutations are a common phenomenon in EBV-associated HD, GC, and AIDS-lymphoma; 2) the mutation rate does not vary in these geographic areas and ethnic groups; 3) EBNA-4 mutations in EBV-associated United States and Brazilian HD, United States and Japanese GC, and United States AIDS lymphomas are not related to patients' HLA-A11 status.

Heteroplasmy in hair: Differences among hair and blood from the same individuals are still a matter of debate

The analysis of mitochondrial DNA (mtDNA) is a useful tool in forensic cases when sample contents too little or degraded nuclear DNA to genotype by autosomal short tandem repeat (STR) loci, but it is especially useful when the only forensic evidence is a hair shaft. Several authors have related differences in mtDNA from different tissues within the same individual, with high frequency of heteroplasmic variants in hair, as also in some other tissues. Is still a matter of debate how the differences influence the interpretation forensic protocols. One difference between two samples supposed to be originated from the same individual are related to an inconclusive result, but depending on the tissue and the position of the difference it should have a different interpretation, based on mutation-rate heterogeneity of mtDNA. In order to investigate it differences in the mtDNA control region from hair hafts and blood in our population, sequences from the hypervariable regions 1 and 2 (HV1 and HV2) from 100 Brazilian unrelated individuals were compared. The frequency of point heteroplasmy observed in hair was 10.5% by sequencing. Our study confirms the results related by other authors that concluded that small differences within tissues should be interpreted with caution especially when analyzing hair samples. (C) 2007 Elsevier B.V.. All rights reserved.

Myostatin (GDF8) single nucleotide polymorphisms in Nellore cattle

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Kras oncogene analysis of non-melanoma skin tumors in Southeastern Brazil

Skin cancers are the most common human malignant neoplasia and their incidence is growing, chiefly in tropical countries. There is evidence that ultraviolet (UV) radiation present in sunlight is important for genetic damage. Mutations due to such damage could be responsible for alterations in oncogenes and tumor suppressor genes. Recent studies have reported remarkable differences in mutation frequency of the RAS proto-oncogene in non-melanoma skin cancers. These findings may reflect differences in the molecular epidemiology of cutaneous tumors found in geographical areas with diverse sun exposure and ethnical origins of their populations. Our study proposed to perform molecular analyses of skin tumors on patients living in southeastern Brazil, in areas with high levels of sun exposure. DNA from eight solar keratose (SK), 26 basal cell carcinomas (BCC) and 19 squamous cell carcinomas (SCC) was submitted to PCR-SSCP analysis for codons 12, 13 and 61. Contradicting other authors, we found no mutations in codons 12,13 but detected two BCCs and one SCC with a mutation in codon 61. These findings suggest that the activation of KRAS oncogene may contribute to the pathogenicity of cutaneous lesions in southeastern Brazil.

Genetic diversity of microsatellite loci in Leopardus pardalis, Leopardus wiedii and Leopardus tigrinus

The microsatellite loci FCA045, FCA077, FCA008, and FCA096 are highly variable molecular markers which were used to determine the genetic diversity in 148 captive Leopardus sp. The PCR-amplified products of microsatellite loci were characterized in ABI Prism 310 Genetic Analyzer. Allele numbers, heterozygosity, polymorphism information content, exclusive allele number, and shared alleles were calculated. Sixty-five alleles were found and their sizes ranged from 116 to 216 bp in four microsatellite loci. The heterozygosity ranged from 0.36 to 0.81 in Leopardus pardalis, 0.57 to 0.67 in L. tigrinus and 0.80 to 0.92 in L. wiedii. The polymorphism information content was from 0.80 to 0.88 in L. pardalis, 0.76 to 0.88 in L. tigrinus and 0.77 to 0.90 in L. wiedii. The margay (L. wiedii) showed the highest index of polymorphism among the three species in this study. These results imply that microsatellite DNA markers can help in the study of the genetic diversity of Leopardus specimens. ©FUNPEC-RP.

On Hepatitis C Virus Evolution: The Interaction between Virus and Host towards Treatment Outcome

Background:Hepatitis C is a disease spread throughout the world. Hepatitis C virus (HCV), the etiological agent of this disease, is a single-stranded positive RNA virus. Its genome encodes a single precursor protein that yields ten proteins after processing. NS5A, one of the non-structural viral proteins, is most associated with interferon-based therapy response, the approved treatment for hepatitis C in Brazil. HCV has a high mutation rate and therefore high variability, which may be important for evading the immune system and response to therapy. The aim of this study was to analyze the evolution of NS5A quasispecies before, during, and after treatment in patients infected with HCV genotype 3a who presented different therapy responses.Methods:Viral RNA was extracted, cDNA was synthesized, the NS5A region was amplified and cloned, and 15 clones from each time-point were sequenced. The sequences were analyzed for evolutionary history, genetic diversity and selection.Results:This analysis shows that the viral population that persists after treatment for most non-responder patients is present in before-treatment samples, suggesting it is adapted to evade treatment. In contrast, the population found in before treatment samples from most end-of-treatment responder patients either are selected out or appears in low frequency after relapse, therefore changing the population structure. The exceptions illustrate the uniqueness of the evolutionary process, and therefore the treatment resistance process, in each patient.Conclusion:Although evolutionary behavior throughout treatment showed that each patient presented different population dynamics unrelated to therapy outcome, it seems that the viral population from non-responders that resists the treatment already had strains that could evade therapy before it started. © 2013 Bittar et al.

Polymorphisms of estrogen receptor-α gene in Brazilian women with high breast density after menopause

The association of genetic polymorphism in the estrogen receptor alpha (ERα) gene and risk for diseases including breast cancer (BC) has been the subject of great interest. Objective: Checking on women with high breast density after menopause, the frequency of the Pvull and Xbal polymorphisms of the ERα gene and the correlation between them and the known risk factors for breast cancer. Method: Observational study with 308 women between 45 and 65 years old with high breast density, without hormonal therapy, menstruation for a year or more, breast and ovarian cancer history. It was characterized in clinical history and physical examination: menarche, menopause, parity, family history of BC, smoking, alcohol intake and body mass index. Results: The allelic and genotypic frequencies for ERα-Pvull and Xbal: p=43.99%; p=56.01%; pp=32.14%; Pp=47.73% and PP=20.13%; X=41.56%; x=58.44%; xx=33.44%; Xx=50.00% and XX=16.56%, respectively. The most frequent risk factors for BC: menarche before 12 years old (35.38%), nulliparity or first child after 28 years old (41.66%), family history of BC (19.16%) and overweight/obesity (62.01%). Conclusion: Allelic and genotypic distribution similar to literature. The risk factors for BC were more prevalent in women with high breast density but without significant associations with these polymorphisms. © 2013 Informa UK Ltd. All rights reserved.

Relações filogenéticas e história evolutiva do gênero Astyanax (Teleostei: Characidade), com base em caracteres moleculares

Pós-graduação em Ciências Biológicas (Biologia Celular e Molecular) - IBRC

Estudo de SNPs do cromossomo Y na população do Estado do Espirito Santo, Brasil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo comparativo in vitro da suscetibilidade à ciprofloxacina e à vancomicina em linhagens de Enterococcus faecalis isoladas de processos infecciosos

Pós-graduação em Doenças Tropicais - FMB

Evolução das quasiespécies da proteína NS5A do vírus da hepatite C genótipo 3a

Pós-graduação em Genética - IBILCE

Cryptic species of Paracoccidioides brasiliensis: impact on paracoccidioidomycosis immunodiagnosis

We aimed to evaluate whether the occurrence of cryptic species of Paracoccidioides brasiliensis, S1, PS2, PS3 and Paracoccidioides lutzii, has implications in the immunodiagnosis of paracoccidioidomycosis (PCM). Small quantities of the antigen gp43 were found in culture filtrates of P. lutzii strains and this molecule appeared to be more variable within P. lutzii because the synonymous-nonsynonymous mutation rate was lower, indicating an evolutionary process different from that of the remaining genotypes. The production of gp43 also varied between isolates belonging to the same species, indicating that speciation events are important, but not sufficient to fully explain the diversity in the production of this antigen. The culture filtrate antigen AgEpm83, which was obtained from a PS3 isolate, showed large quantities of gp43 and reactivity by immunodiffusion assays, similar to the standard antigen (AgB-339) from an S1 isolate. Furthermore, AgEpm83 was capable of serologically differentiating five serum samples from patients from the Botucatu and Jundiaí regions. These patients had confirmed PCM but, were non-reactive to the standard antigen, thus demonstrating an alternative for serological diagnosis in regions in which S1 and PS2 occur. We also emphasise that it is not advisable to use a single antigen preparation to diagnose PCM, a disease that is caused by highly diverse pathogens.

Hepatitis C virus molecular evolution: Transmission, disease progression and antiviral therapy

Hepatitis C virus (HCV) infection represents an important public health problem worldwide. Reduction of HCV morbidity and mortality is a current challenge owned to several viral and host factors. Virus molecular evolution plays an important role in HCV transmission, disease progression and therapy outcome. The high degree of genetic heterogeneity characteristic of HCV is a key element for the rapid adaptation of the intrahost viral population to different selection pressures (e.g., host immune responses and antiviral therapy). HCV molecular evolution is shaped by different mechanisms including a high mutation rate, genetic bottlenecks, genetic drift, recombination, temporal variations and compartmentalization. These evolutionary processes constantly rearrange the composition of the HCV intrahost population in a staging manner. Remarkable advances in the understanding of the molecular mechanism controlling HCV replication have facilitated the development of a plethora of direct-acting antiviral agents against HCV. As a result, superior sustained viral responses have been attained. The rapidly evolving field of anti-HCV therapy is expected to broad its landscape even further with newer, more potent antivirals, bringing us one step closer to the interferon-free era. (C) 2014 Baishideng Publishing Group Inc. All rights reserved.

Análise de polimorfismos INDELs na identificação humana

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)