Active and exo-site inhibition of human factor Xa: Structure of des-Gla factor Xa inhibited by NAP5, a potent nematode anticoagulant protein from Ancylostoma caninum

Hookworms are hematophagous nematodes capable of growth, development and subsistence in living host systems such as humans and other mammals. Approximately one billion, or one in six, people worldwide are infected by hookworms causing gastrointestinal blood loss and iron deficiency anemia. The hematophagous hookworm Ancylostoma caninum produces a family of small, disulfide-linked protein anticoagulants (75-84 amino acid residues). One of these nematode anticoagulant proteins, NAP5, inhibits the amidolytic activity of factor Xa (fXa) with K-i = 43 pM, and is the most potent natural fXa inhibitor identified thus far. The crystal structure of NAP5 bound at the active site of gamma-carboxyglutamic acid domainless factor Xa (des-fXa) has been determined at 3.1 angstrom resolution, which indicates that Asp189 (fXa, S1 subsite) binds to Arg40 (NAP5, P1 site) in a mode similar to that of the BPTI/trypsin interaction. However, the hydroxyl group of Ser39 of NAP5 additionally forms a hydrogen bond (2.5 angstrom) with His57 NE2 of the catalytic triad, replacing the hydrogen bond of Ser195 OG to the latter in the native structure, resulting in an interaction that has not been observed before. Furthermore, the C-terminal extension of NAP5 surprisingly interacts with the fXa exosite of a symmetry-equivalent molecule forming a short intermolecular beta-strand as observed in the structure of the NAPc2/fXa complex. This indicates that NAP5 can bind to fXa at the active site, or the exosite, and to fX at the exosite. However, unlike NAPc2, NAP5 does not inhibit fVIIa of the fVIIa/TF complex. (c) 2007 Elsevier Ltd. All rights reserved.

Geographical variation in genetic structure of an Atlantic Coastal Forest frog reveals regional differences in habitat stability

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

The fate of copepod populations in the Paranapanema River (São Paulo, Brazil), downstream from the Jurumirim dam

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The population genetic structure of Rhizoctonia solani AG-3PT from potato in the Colombian Andes

The soilborne fungus Rhizoctonia solani anastomosis group 3 (AG-3PT) is a globally important potato pathogen. However, little is known about the population genetic processes affecting field populations of R. solani AG-3PT, especially in the South American Colombian Andes, which is near the center of diversity of the two most common groups of cultivated potato, Solanum tuberosum and S. phureja. We analyzed the genetic structure of 15 populations of R. solani AG-3PT infecting potato in Colombia using 11 simple-sequence repeat (SSR) markers. In total, 288 different multilocus genotypes were identified among 349 fungal isolates. Clonal fractions within field populations were 7 to 33%. R ST statistics indicated a very low level of population differentiation overall, consistent with high contemporary gene flow, though moderate differentiation was found for the most distant southern populations. Genotype flow was also detected, with the most common genotype found widely distributed among field populations. All populations showed evidence of a mixed reproductive mode, including both asexual and sexual reproduction, but two populations displayed evidence of inbreeding. © 2013 The American Phytopathological Society.

Temporal and Spatial Scaling of the Genetic Structure of a Vector-Borne Plant Pathogen

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

High levels of genetic differentiation and selfing in the Brazilian cerrado fruit tree Dipteryx alata Vog. (Fabaceae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A set of polymorphic microsatellite loci for Vriesea gigantea and Alcantarea imperialis (Bromeliaceae) and cross-amplification in other bromeliad species

Fifteen polymorphic microsatellite markers were isolated and characterized in two species of Bromeliaceae: Vriesea gigantea and Alcantarea imperialis. The number of alleles observed for each locus ranged from three to 16. The loci will be used for studies of the genetic structure of natural populations, reproductive biology, and evolutionary relationships among and within these genera. A cross-amplification test in 22 taxa suggests that the markers will be useful for similar applications in numerous other bromeliad species.

Evolutionary history of Scinax treefrogs on land-bridge islands in south-eastern Brazil

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

Comparative population biology of Uca rapax (Smith, 1870) (Brachyura, Ocypodidae) from two subtropical mangrove habitats on the Brazilian coast

The structure of two populations of the fiddler crab Uca rapax in two subtropical mangrove habitats near Ubatuba, State of São Paulo, Brazil were compared. The size - frequency distribution, sex ratio, and recruitment were evaluated. Sampling was performed monthly from April 2001 to March 2002 in the Itamambuca and Ubatumirim habitats. Crabs were caught manually for 15 min by two collectors during low tide. The carapace width of each crab was measured with a digital caliper, and the sex and ovigerous state were recorded. The median size of the carapace width of males was greater than that of females at both sites (P<0.05). The median size of the crabs from Itamambuca was larger than at Ubatumirim (P<0.05). Only 28 ovigerous females were obtained from both mangroves, which suggested that females might remain in their burrows during the incubation period. The highest recruitment pulse occurred in winter for both populations, probably as a consequence of high reproductive activity during summer. The sex ratio in the size classes showed an anomalous pattern, with a higher frequency of females in the intermediate size classes. This may be related to a greater energy requirement for reproduction in females, thus delaying growth. The variable environmental conditions to which Uca rapax populations are subject appear to act directly or indirectly on the population, causing variations in growth and reproductive processes in the different populations investigated here.

Natural Conditions and Environmental Impacts in a Coastal Hydrographic Basin in the Brazilian Amazon

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Chromosomal organization of repetitive DNA sequences in Astyanax bockmanni (Teleostei, Characiformes): dispersive location, association and co-localization in the genome

Repetitive DNA sequences constitute a great portion of the genome of eukaryotes and are considered key components to comprehend evolutionary mechanisms and karyotypic differentiation. Aiming to contribute to the knowledge of chromosome structure and organization of some repetitive DNA classes in the fish genome, chromosomes of two allopatric populations of Astyanax bockmanni were analyzed using classic cytogenetics techniques and fluorescent in situ hybridization, with probes for ribosomal DNA sequences, histone DNA and transposable elements. These Astyanax populations showed the same diploid number (2n = 50), however with differences in chromosome morphology, distribution of constitutive heterochromatin, and location of 18S rDNA and retroelement Rex3 sites. In contrast, sites for 5S rDNA and H1, H3 and H4 histones showed to be co-located and highly conserved. Our results indicate that dispersion and variability of 18S rDNA and heterochromatin sites are not associated with macro rearrangements in the chromosome structure of these populations. Similarly, distinct evolutionary mechanisms would act upon histone genes and 5S rDNA, contributing to chromosomal association and co-location of these sequences. Data obtained indicate that distinct mechanisms drive the spreading of repetitive DNAs in the genome of A. bockmanni. Also, mobile elements may account for the polymorphism of the major rDNA sites and heterochromatin in this genus. © 2013 Springer Science+Business Media Dordrecht.

Variabilidade populacional de Plutella xylostella (L., 1758) (Lepidoptera: Plutellidae) e suscetibilidade a Bacillus thuringiensis Berliner

Pós-graduação em Agronomia (Entomologia Agrícola) - FCAV

Estudos de variabilidade genética em populações de Chrysoperla externa Hagen, 1861 (Neuroptera: Chrysopidae) do estado de São Paulo, Brasil

Pós-graduação em Agronomia (Entomologia Agrícola) - FCAV

Caracterização molecular da estrutura genética de populações e espécies camarões palemonídeos Macrobrachium do gênero Macrobrachium

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)