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Biomedical subjects

L G Pereira

Publications and source records attributed to L G Pereira.

7 recordsLinked to original sources
PubMed2004

Pattern of elevational distribution and richness of non volant mammals in Itatiaia National Park and its surroundings, in southeastern Brazil.

Itatiaia National Park (PNI) and its surroundings present a unique fauna due to different forest formations with well-defined climatic and vegetation bands. The Itatiaia massif has four vegetation types that follow an altitudinal gradient: lower montane forest, montane forest, upper montane forest, and Campos de Altitude. Hence, this region is ideal for studying geographical variation in biological diversity. The main objectives of this study were to report on nonvolant mammal species known to occur in Itatiaia National Park and its surroundings and to determine if their distributional pattern is related to elevation. A review of the literature and a complete survey of specimens deposited in museums, as well as small-mammal trapping were carried out in order to obtain a complete record of the species from the region. Precise locality data were obtained for all specimens recorded, allowing the inclusion of each collected or observed individual in an altitude and vegetational class. We made a direct ordination gradient of marsupial, primate, and rodent species abundance with the altitude. Sixty-nine mammal species were collected or reported for the Itatiaia massif, belonging to seven orders and 20 families. Of these, 33 species (47.8%) are included in the official list of threatened or believed-to-be threatened species in Rio de Janeiro State. The orders Rodentia, Carnivora, and Didelphimorphia had the highest species richness, with 25, 14, and 13 species respectively. When species were grouped according to the vegetation, 16 species occured in the lower montane, 56 in the montane forest, five in the upper montane, and 21 in the high-altitude fields (Campos de Altitude). The communities of marsupials, primates, and rodents have an ordination pattern related to the altitude. Species richness was higher between 500 m and 1,500 m above sea level in montane forest, which is in agreement with recent studies showing that species richness can reach its maximum at mid-elevations.

Altitude↗
PubMed2000

Nature and distribution of constitutive heterochromatin and NOR location in the grasshopper Phaeoparia megacephala (Romaleidae: Orthoptera).

The constitutive heterochromatin (CH) of Phaeoparia megacephala was studied using C-banding and fluorochrome staining (CMA3, DAPI and acridine orange). The nucleolar organizer regions (NOR) were identified with silver staining. The chromosome complement of this species was 2n = 23, XO in males, and 2n = 24, XX in females. The CH was pericentromeric in all chromosomes. L1, L2, L3 and X chromosomes showed large blocks of CH, while the medium and small chromosomes had small blocks. The staining procedure with acridine orange revealed the same pattern. All the pericentromeric regions showed small blocks of CMA3-positive constitutive heterochromatin (GC-rich regions), while only part of the large C-band positive chromosome segments (L1, L2, L3 and X) were CMA3 positive. This character demonstrates an uncommon heterogeneity of constitutive heterochromatin in P. megacephala. The fluorochrome DAPI did not reveal DAPI-positive regions (AT-rich regions). Silver staining revealed only one pair of medium chromosomes with NOR.

Animals↗
PubMed1994

Antigenic structure of the coat protein of potato mop-top furovirus.

The antigenic structure of the coat protein (CP) of potato mop-top furovirus (PMTV) was studied by electron microscopy of virus particles labeled with gold-conjugated monoclonal antibodies (MAbs) and by the reactions of MAbs with overlapping octapeptides (Pepscan) representing the complete amino acid sequence of the CP. A total of seven epitopes were identified in the CP. MAb SCR 69 detected a continuous epitope, which was located at the extreme N-terminus of the CP, was exposed at the surface along the sides of PMTV particles, and was removed by treating them with trypsin. MAb SCR 68 detected a discontinuous epitope found at the concave end of PMTV particles. Five other epitopes, which were detected by Pepscan tests, were located internally in, and at intervals along, the CP amino acid sequence. A tentative model of the PMTV CP subunit was produced, based on computer-aided prediction of its secondary structure and apparent similarities with the CP of tobacco mosaic virus. In this model, four of the epitopes occur at high radius in each of the pairs of parallel and anti-parallel alpha-helices in the CP subunit. The fifth is at low radius in the putative left radial alpha-helix. The epitope detected by MAb SCR 77, although amenable to study by Pepscan, contains three reactive elements, separated by short runs of nonessential residues, in a sequence of 13 amino acids. In intact virus particles, the CPs of beet necrotic yellow vein furovirus and PMTV apparently differ in the accessibility of their N- and C-termini.

Amino Acid Sequence↗