RESUMO
The devastation in Central America following the 1998 hurricane (Hurricane Mitch) resulted more from economic and political policies than from "natural" disaster. Over the last 30 or 40 years, huge numbers of poor people in these countries have been forced off good, stable agricultural land onto degraded hillsides and into shanty towns constructed on floodplains--areas known to pose serious hazards of flooding and mudslides. This, together with the failure of impoverished countries to anticipate disaster through mass evacuations or to respond effectively to the hurricane's widespread damage--ensured the loss of thousands of lives.
Assuntos
Desastres , Política , Setor Privado , Problemas Sociais , América Central , Países em Desenvolvimento , Planejamento em Desastres , Honduras , Humanos , Cooperação InternacionalRESUMO
A genomic DNA library of Anopheles aquasalis Curry was screened for clones that hybridized more intensely to DNA from A. aquasalis than to DNA from A. benarrochi Gabaldon, Cova Garcia, and Lopez, A. konderi Galvao and Damasceno, A. nuneztovari Gabaldon cytotypes A, B, and C, A. oswaldoi (Peryassu), A. rangeli Gabaldon, Cova Garcia, and Lopez, or A. trinkae Faran. Two specific clones (2.5 kilobasepairs [kbp] and 3.0 kbp) from A. aquasalis were isolated. Both A. aquasalis-specific clones were from the intergenic spacer region of the ribosomal RNA (rRNA) cistron. Upon digestion with Rsa I, a 900-bp fragment from the clone AA-1 hybridized specifically to A. aquasalis DNA. Analysis of the DNA sequence of this fragment revealed four tandemly repeated 36-bp units. Three of these repeat units were identical, and the fourth was 94% identical to the others. The DNA sequence of a highly conserved region of these repeats was used to synthesize an oligonucleotide probe specific to A. aquasalis.
Assuntos
Anopheles/genética , RNA Ribossômico/genética , Sequências Repetitivas de Ácido Nucleico , Animais , Anopheles/classificação , Anopheles/parasitologia , Sequência de Bases , Sondas de DNA/genética , DNA Ribossômico/genética , Feminino , Genes/genética , Biblioteca Genômica , Insetos Vetores/classificação , Insetos Vetores/genética , Insetos Vetores/parasitologia , Malária/transmissão , Dados de Sequência Molecular , RNA Ribossômico 28S/genética , Homologia de Sequência do Ácido Nucleico , América do Sul , Especificidade da EspécieRESUMO
Sequence variation of the ribosomal DNA internal transcribed spacer 2 (ITS2) was examined for populations of the malaria vector Anopheles nuneztovari collected in Colombia, Venezuela, Bolivia, Suriname, and Brazil. Mosquitoes from Colombia and Venezuela had identical ITS2 sequences and were distinguished from sequences in other populations by three insertion/deletion events (indels) and by one transversion. The length of the ITS2 was 363-369 bp, and it had a G+C content of 55.3%-55.7%. Variation in the length of the ITS2 between and within populations was due to indels in simple repeats. ITS2 consensus sequences were similar or identical for samples from the following three groups: (1) Colombia, Bolivia, and Venezuela; (2) Suriname and northern Brazil; and (3) eastern and central Brazil. The presence of two different consensus sequences from a single location near Manaus, Brazil, suggests that populations from eastern Brazil and those from Suriname converge in this region of the Amazon Basin. These data show that putative cryptic species of An. nuneztovari are distinguished by very minor differences in DNA sequence of the ITS2 region.
Assuntos
Anopheles/genética , DNA Ribossômico/genética , Variação Genética , Íntrons , Sequências Repetitivas de Ácido Nucleico , Animais , Sequência de Bases , Feminino , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Reação em Cadeia da Polimerase , Homologia de Sequência do Ácido Nucleico , América do SulRESUMO
Populations of the malaria vector Anopheles aquasalis from Venezuela, Trinidad, and Brazil were analyzed using restriction enzyme digestion of mitochondrial DNA (mtDNA). The five enzymes surveyed yielded 12 mtDNA haplotypes. Three restriction endonuclease profiles (Bcl I, Eco RI, and Hind III) differentiated the Venezuelan and Trinidadian A. aquasalis from two Brazilian populations. Estimates of mtDNA sequence divergence between the Venezuelan/Trinidadian populations and each Brazilian population (0.023-0.032), as well as divergence between the two Brazilian populations (0.030), were within the range of interspecific distances calculated for members of anopheline species complexes. Ribosomal DNA (rDNA) restriction profiles of the A. aquasalis populations examined were identical.