M B Soares

Publications (4)6.3 Total impact

• Article: The Trypanosoma cruzi ribosomal RNA-encoding gene: analysis of promoter and upstream intergenic spacer sequences.

  P Dietrich, M B Soares, M H Affonso, L M Floeter-Winter
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  ABSTRACT: The transcription start point (tsp) of the ribosomal RNA(rRNA)-encoding gene of Trypanosoma cruzi was mapped at 1550 bp upstream from the 18S rRNA coding sequence. The + 1 nucleotide (tsp) was determined to be a guanosine. As described for other eukaryotes, no consensus sequence was found when the putative promoter sequence (-200 to + 50) was compared with that described for Trypanosoma brucei and Crithidia fasciculata. However, a repeated element was found in the upstream intergenic spacer sequence (IGS) of T. cruzi. Motifs, present in this element, exhibit significant homology to the T. cruzi promoter sequence. Furthermore, the same motifs could be found, in a similar sequence organization, within the T. brucei promoter region. Therefore, the data described in this paper strongly indicate that the IGS rDNA (DNA coding for rRNA) organization in trypanosomatids appears similar to that found in higher eukaryotes.
  Gene 04/1993; 125(1):103-7. · 2.34 Impact Factor
• Article: Ribosomal DNA restriction analysis and synthetic oligonucleotide probing in the identification of genera of lower trypanosomatids.

  E P Camargo, C Sbravate, M M Teixeira, S R Uliana, M B Soares, H T Affonso, L Floeter-Winter
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  ABSTRACT: Fifty-four species or isolates of insect trypanosomatids were examined for the presence of selected restriction enzyme sites in the small (SSU) and large (LSU) rRNA coding units of ribosomal genes. In the SSU, sites for Eco RI, Bgl II, Pst I, and Hind III were found to occur at the same location for all species examined, thus displaying a universal distribution among trypanosomatids. In the LSU, a site for Bgl II in the 24S-alpha sequence and sites for Hind III and Pst I in the 24S-beta sequence were found in all species examined. In contrast, a site for Pvu II in the SSU exhibited a genus-related distribution, being present in Crithidia and Herpetomonas but absent in Phytomonas. A site for Hind III in the 24S-alpha sequence of the LSU also exhibited genus-restricted distribution. The site was present in Crithidia but absent in Phytomonas and Herpetomonas. These findings were confirmed by dot hybridization with a synthetic oligonucleotide complementary to the 18S rRNA sequence containing the Pvu II site. Results point to the usefulness of restriction markers as diagnostic tools for distinguishing the lower trypanosomatid genera Crithidia, Herpetomonas, and Phytomonas at the same time revealing a marked complexity within the genus Leptomonas.
  Journal of Parasitology 03/1992; 78(1):40-8. · 1.40 Impact Factor
• Article: Restriction fragment length polymorphisms in the ribosomal gene spacers of Trypanosoma cruzi and Trypanosoma conorhini.

  P Dietrich, M del P Dussan, L M Floeter-Winter, M H Affonso, E P Camargo, M B Soares
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  ABSTRACT: The ribosomal RNA genes of two species of Trypanosoma, Trypanosoma cruzi, the etiological agent of Chagas' disease, and Trypanosoma conorhini, a non-pathogenic rodent trypanosome, were cloned and partially characterized. The physical maps derived for their rRNA genes were similar throughout the region that encompasses the SSU-and LSU-rRNA coding sequences. However, the non-transcribed spacer DNA of both T. cruzi and T. conorhini was found to be polymorphic for several restriction enzyme sites. We show that strains of T. cruzi can be typed according to the characteristic restriction fragment length polymorphism of their NTS DNAs.
  Molecular and Biochemical Parasitology 09/1990; 42(1):13-9. · 2.55 Impact Factor
• Article: The Trypanosoma cruzi ribosomal RNA-encoding gene: analysis of promoter and upstream intergenic spacer sequences

  P. Dietrich, M.B. Soares, M.H.T. Affonso, L.M. Floeter-Winter
  [show abstract] [hide abstract]
  ABSTRACT: The transcription start point (tsp) of the ribosomal RNA(rRNA)-encoding gene of Trypanosoma cruzi was mapped at 1550 bp upstream from the 18S rRNA coding sequence. The +1 nucleotide (tsp) was determined to be a guanosine. As described for other eukaryotes, no consensus sequence was found when the putative promoter sequence (— 200 to + 50) was compared with that described for Trypanosoma brucei and Crithidia fasciculata. However, a repeated element was found in the upstream intergenic spacer sequence (IGS) of T. cruzi. Motifs, present in this element, exhibit significant homology to the T. cruzi promoter sequence. Furthermore, the same motifs could be found, in a similar sequence organization, within the T. brucei promoter region. Therefore, the data described in this paper strongly indicate that the IGS rDNA (DNA coding for rRNA) organization in trypanosomatids appears similar to that found in higher eukaryotes.
  Gene.