Screening and characterization of sex-specific DNA fragments in the freshwater fish matrinch, Brycon amazonicus (Teleostei: Characiformes: Characidae)

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

Two 5S rDNA arrays in Neotropical fish species: is it a general rule for fishes ?

In this paper we describe Southern blot hybridization results probed with 5S rRNA genes for several Neotropical fish species representing different taxonomic groups. All the studied species showed a general trend with the 5S rDNA tandem repeats organized in two distinct size-classes. At the same time, data on 5S rDNA organization in fish genome were summarized. Previous information on the organization and evolution of 5S rRNA gene arrays in the genome of this vertebrate group are in agreement with the Southern results here presented. Sequences obtained for several fish species have revealed the occurrence of two distinct 5S rDNA classes characterized by distinct non-transcribed spacer sequences, which are clustered in different chromosomes in some species. Moreover, the 5S rDNA loci are generally distributed in an interstitial position in the chromosomes and they are usually not syntenic to the 45S rDNA. The presence of two classes of 5S rDNA in several non-related fish species suggests that this could be a common condition for the 5S rRNA gene organization in the fish genome.

Dynamics of 5S rDNA in the tilapia (Oreochromis niloticus) genome: repeat units, inverted sequences, pseudogenes and chromosome loci

In higher eukaryotes, the 5S ribosomal DNA (5S rDNA) is organized in tandem arrays with repeat units composed of a coding region and a non-transcribed spacer sequence (NTS). These tandem arrays can be found on either one or more chromosome pairs. 5S rDNA copies from the tilapia fish. Oreochromis niloticus, were cloned and the nucleotide sequences of the coding region and of the non-transcribed spacer were deter-mined. Moreover, the genomic organization of the 5S rDNA tandem repeats was investigated by fluorescence in situ hybridization (FISH) and Southern blot hybridization. Two 5S rDNA classes, one consisting of 1.4-kb repeats and another one with 0.5-kb repeats were identified and designated 5S rDNA type I and type II, respectively, An inverted 5S rRNA gene and a 5S rRNA putative pseudogene were also identified inside the tandem repeats of 5S rDNA type I. FISH permitted the visualization of the 5S rRNA genes at three chromosome loci, one of them consisting of arrays of the 5S rDNA type I, and the two others corresponding to arrays of the 5S rDNA type II. The two classes of the 5S rDNA. The presence of pseudogenes, and the inverted genes observed in the O. niloticus genome might be a consequence of the intense dynamics of the evolution of these tandem repeat elements. Copyright (C) 2002 S. Karger AG, Basel.

The prevalence of human papillomavirus in the oropharynx in healthy individuals in a Brazilian population

Oncogenic human papillomavirus (HPV), a causative agent of uterine cervical cancer, has also been detected in head and neck squamous cell cancers, especially in squamous cell carcinomas of the tonsils. However, the true HPV prevalence in normal and neoplasic oropharyngeal mucosa remains uncertain. To determine the prevalence of HPV DNA in normal oropharyngeal mucosa of cancer-free individuals, a study was carried out on 50 Brazilian subjects. PCR was performed to identify HPV DNA in samples from four sites in the oropharynx (tonsils, soft palate, base of the tongue, and back wall of the pharynx). For amplification of the HPV DNA, MY09/11 consensus primerswere used, and specific genotypes were identified by dot-blot hybridization or cloning and sequencing. HPV DNA was present in 14.0% of the individuals, and the identified genotypes were 16, 18, 52, and 61. All these types are considered high-risk (HR) HPV. The tonsils and the soft palate were the sites with the highest HPV prevalence. This study shows the prevalence of HR HPV in the oropharynx of normal individuals. However, the prevalence of HPV is still unclear, and if HPV infection in a healthy it is not known individual predisposes to HPV-associated disease such as oropharyngeal cancer. Thus, it is important to assess the prevalence of HPV in cancer-free individuals, in order to compare it with the HPV prevalence in oropharyngeal carcinomas and to attempt to determine the true role of HPV in the development of head and neck squamous cell cancers. (c) 2006 Wiley-Liss, Inc.

Limited movement of Cucumber mosaic virus (CMV) in yellow passion flower in Brazil

Symptoms of Cucumber mosaic virus (CMV) on yellow passion flower (Passiflora edulis f. flavicarpa) are characterized by bright yellow mottling on leaves, starting at random points on the vine and diminishing in intensity towards the tip, which becomes symptomless as it grows. To determine whether symptomless portions of vines are CMV-free or represent latent infection, leaves with and without symptoms were collected from infected vines in the field. Biological, serological (plate-trapped antigen enzyme-linked immunosorbent assay, PTA-ELISA), Western blot and dot-blot hybridization assays showed that portions of the vines without symptoms were CMV-free. Vegetatively propagated vines with symptoms showed remission of symptoms on newly developed leaves. One year later, no CMV was detected in the upper leaves of these plants. Mechanically inoculated passion flower seedlings behaved similarly; symptoms were shown by few leaves after inoculation. Afterwards, plants became symptomless and CMV was not detected in the upper leaves or root system, 40 or 85 days after inoculation. The mechanism responsible for remission of symptoms accompanied by CMV disappearance is not known.

Nucleotide sequence, genomic organization and chromosome localization of 5S rDNA in two species of Curimatidae (Teleostei, Characiformes)

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

Partial molecular characterization of the Nile tilapia (Oreochromis niloticus) alpha-cardiac muscle actin gene and its relationship to actin isoforms of other fish species

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

Deletion of Epstein-Barr virus latent membrane protein 1 gene in United States and Brazilian Hodgkin's disease and reactive lymphoid tissue: High frequency of a 30-bp deletion

A 30-basepair (bp) deletion in the Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) gene has been reported in nasopharyngeal carcinoma and EBV-associated malignant lymphomas. Prior studies have found the deletion in about 10% to 28% of cases of Hodgkin's disease (HD), particularly in cases with aggressive histology. We studied the prevalence of 30-bp LMP1 gene deletion in EBV-positive HD in the United States (US) (12 cases) and Brazil (26 cases) with comparison to reactive lymphoid tissues (21 cases) and HD without EBV-positive Reed-Sternberg cells (15 cases). We studied the status of the LMP1 gene by Southern blot hybridization of polymerase chain reaction (PCR) products obtained after amplification with primers spanning the site of the deletion. We also performed EBV typing, EBER1 in situ hybridization, and LMP1 protein immunohistochemistry. EBV was detected in 12/26 (46%) cases of HD from the US and 26/27 (96%) cases of Brazilian HD. The 30-bp LMP1 gene deletion was observed in 4/12 (33%) cases of EBV-positive HD from US, and 12/26 (46%) cases of Brazilian EBV-positive HD, including 3 cases of type B EBV, as compared with 12/21 (57%) reactive lymphoid tissues and 9/15 (60%) cases of EBV-negative HD. US and Brazilian HD showed a higher prevalence of the 30-bp LMP1 gene deletion, compared with studies of others. The unexpected finding of high incidence of 30-bp deletion in LMP1 gene in reactive lymphoid tissue and HD without EBV-positive Reed-Sternberg cells suggests that this deletion may not be relevant to HD pathogenesis in most cases. Copyright (C) 1997 by W.B. Saunders Company.

GLUCOCORTICOID-REGULATED GENE IN TRANSFORMED TO NORMAL PHENOTYPIC REVERSION

Glucocorticoid hormones modulate the actions of peptide growth factors and constitute important therapeutic tools as anti-inflammatory and anti-tumor agents. The C6 rat glioma cell line responds to glucocorticoids with changes in morphology and growth block. The hyper-responsive ST1 cell variant displays a dramatic phenotypic reversion under the influence of these hormones. Thus, the transformed and tumorigenic cells reversibly change to a normal and non-tumorigenic phenotype. In addition, the cells also produce a C-type retrovirus. We used poly A(+) mRNA from ST1 cells that had been treated with hydrocortisone to generate a cDNA library that was then screened, by differential hybridization,for glucocorticoid-responsive cellular sequences. The retroviral genomic RNA was used to generate a viral-specific probe. Cross hybridization led to the isolation of at least 4 cDNA clones of which 3 are cellular sequences and one corresponds to a retroviral gene. These clones were characterized by DNA sequencing and Northern blot hybridization analysis.

A LINE2 repetitive DNA sequence from the cichlid fish, Oreochromis niloticus: sequence analysis and chromosomal distribution

We report the cloning and characterization of a long interspersed nucleotide element (LINE) fi-om a cichlid fish, Oreochromis niloticus, and show the distribution of this element, called CiLINE2 for cichlid LINE2, in the chromosomes of this species. The identification of an open reading frame in CiLINE2 with amino acid sequence similarity to reverse transcriptases encoded by LINE-like elements in Caenorhabditis elegans, Platemys spixii, Schistosoma mansoni, Gallus gallus (CRI), Drosophila melanogaster (I factor), and Homo sapiens (LINE2), as well as the structure of the element, suggest it is a member of this family of non-long terminal repeat-containing retrotransposons. Search of a DNA sequence database identified sequences similar to CiLINE2 in four other fish species (Haplotaxodon microlepis, Oreochromis mossambicus, Pseudotropheus zebra, and Fugu rubripes). Southern blot hybridization experiments revealed the presence of sequences similar to CiLINE2 in all Tilapiini species analyzed from the genera Oreochromis, Tilapia, and Sarotherodon, and gave an estimated copy number of about 5500 for the haploid genome of O. niloticus. Fluorescent in situ hybridization showed that CiLINE2 sequences were organized in small clusters dispersed over all chromosomes of O. niloticus, with a higher concentration near chromosome ends. Furthermore the long arm of chromosome 1 was strikingly enriched with this sequence. The distribution of LINE2-related elements might underlie the difference in chromosome banding patterns observed between cold-blooded vertebrates and mammals.

O-serogroups, eae gene and EAF plasmid in Escherichia coli isolates from cases of bovine mastitis in Brazil

Mastitis has been recognized for some time as the most costly disease in dairy herds. From March 1997 to August 1998. 2144 samples of bovine mastitic milk were collected, from which 182 Escherichia coli isolates were made, and from which 14 1 isolates had the somatic anti-en (serogroup) determined. Twelve different serogroups were isolated from mastitic milk, and among them were 026, 055, 0111 and 0 119, all of them classic enteropathogenic E. (oh (EPEC) serogroups. These represented 40.0% of the isolates. The 20 of 57 isolates tested had plasmids and in dot blot hybridization, nine isolates were positive for an EaeA probe and an EPEC adherence factor (EAF) probe while two isolates were negative for EaeA probe but positive for the EAF probe, the nine isolates were characterized as attaching and effacing (A/E) E, coli (AEEC) isolates. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Molecular and cytogenetic analysis of the telomeric (TTAGGG)n repetitive sequences in the Nile tilapia, Oreochromis niloticus (Teleostei: Cichlidae)

The majority of chromosomes in Oreochromis niloticus, as with most fish karyotyped to date, cannot be individually identified owing to their small size. As a first step in establishing a physical map for this important aquaculture species of tilapia we have analyzed the location of the vertebrate telomeric repeat sequence, (TTAGGG)n, in O. niloticus. Southern blot hybridization analysis and a Bal31 sensitivity assay confirm that the vertebrate telomeric repeat is indeed present at O. niloticus chromosomal ends with repeat tracts extending for 4-10 kb on chromosomal ends in erythrocytes. Fluorescent in situ hybridization revealed that (TTAGGG)n is found not only at telomeres, but also at two interstitial loci on chromosome 1. These data support the hypothesis that chromosome 1, which is significantly larger than all the other chromosomes in the karyotype, was produced by the fusion of three chromosomes and explain the overall reduction of chromosomal number from the ancestral teleost karyotype of 2n=48 to 2n=44 observed in tilapia.

Isolamento e caracterização de marcadores de DNA associados ao sexo e segmentos de DNA repetitivo em espécies do gênero Brycon (Characidae, Bryconinae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Método imunocromatográfico para pesquisa do anticorpo em triagem ou diagnóstico da hepatite C: desenvolvimento e aplicação clínica

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

Papilomavírus humano associado a lesões de cérvice uterina

Estudou-se a prevalência do papilomavírus humano (HPV) em 228 mulheres portadoras de lesões em cérvice uterina, atendidas no Instituto Ofir Loiola, em Belém, Pará, no período de março de 1992 a maio de 1996. As pacientes foram submetidas à biópsia de colo uterino, sendo o material encaminhado para histopatologia e pesquisa de HPV por PCR e hibridização por dot-blot. Distribuíram-se as participantes em três grupos, conforme diagnóstico histopatológico. O grupo A constituiu-se de 155 mulheres com carcinoma epidermóide invasor ou com adenocarcinoma, o grupo B de 54 portadoras de neoplasia intra-epitelial cervical grau II ou III, e o grupo C de 19 pacientes com cervicite crônica. Observaram-se prevalências de HPV em 70,3%, 63,0% e 36,8% das mulheres dos grupamentos A, B e C, respectivamente, sendo o HPV 16 registrado em 60,4% das amostras positivas do grupo A e 54,5% daquelas do grupo B. Os tipos 16, 18 e 33 representaram 71,4% dos detectados no grupo C.