Transposition burst of mariner-like elements in the sequenced genome of Rhodnius prolixus.

Transposable elements (TEs) are widespread in insect's genomes. However, there are wide differences in the proportion of the total DNA content occupied by these repetitive sequences in different species. We have analyzed the TEs present in R. prolixus (vector of the Chagas disease) and showed that 3.0% of this genome is occupied by Class II TEs, belonging mainly to the Tc1-mariner superfamily (1.65%) and MITEs (1.84%). Interestingly, most of this genomic content is due to the expansion of two subfamilies belonging to: irritans himar, a well characterized subfamily of mariners, and prolixus1, one of the two novel subfamilies here described. The high amount of sequences in these subfamilies suggests that bursts of transposition occurred during the life cycle of this family. In an attempt to characterize these elements, we performed an in silico analysis of the sequences corresponding to the DDD/E domain of the transposase gene. We performed an evolutionary analysis including network and Bayesian coalescent-based methods in order to infer the dynamics of the amplification, as well as to estimate the time of the bursts identified in these subfamilies. Given our data, we hypothesized that the TE expansions occurred around the time of speciation of R. prolixus around 1.4 mya. This suggestion lays on the "Transposon Model" of TE evolution, in which the members of a TE population that are replicative active are present at multiple loci in the genome, but their replicative potential varies, and of the "Life Cycle Model" that states that when present-day TEs have been involved in amplification bursts, they share an ancestral copy that dates back to this initial amplification.

Seroreactivity to HIV-1 V3 subtypes A to H peptides of Argentinian HIV-positive sera.

Serologic assays could be useful for determining circulating subtypes in different geographic regions. A total of 175 serum samples from the same number of Argentinian HIV-infected patients from Buenos Aires and Rosario were tested against a panel of peptides representing V3 consensus subtypes A through H. A V3 peptide enzyme immunoassay was used for screening the sera. Most sera were reactive with peptides representing subtypes B (58.28%), F (13.14%), and A (8.57%). Cross-reactivity between the remainder of the peptides was observed. Genotypes of eight patients from Rosario were determined and compared with serotyping. Results showed that seven of eight genotyped patients reacted with their respective consensus B peptide and one reacted with consensus B and F. V3 peptide serology proved to be useful for determining HIV-1 clades circulating in Argentina.

PIP: 175 serum samples were collected from 175 HIV-infected Argentineans in Buenos Aires and Rosario during 1987-95, for testing against a panel of peptides representing V3 consensus HIV-1 subtypes A through H. A V3 peptide enzyme immunoassay was used to screen the sera. 58.28% of the sera were infected with HIV-1 subtype B, 13.14% with subtype F, 8.57% with subtype A, 4% with subtype H, 2.85% with subtype D, 2.28% with subtype G, and 1.71% with subtype C. Some cross-reactivity between peptides was observed. Peripheral blood mononuclear cells (PBMCs) were obtained from 8 HIV-infected subjects from Rosario for use in determining genotypes. 7 of the 8 genotyped patients reacted with their respective consensus B peptide and 1 reacted with consensus B and F. V3 peptide serology proved useful in determining which HIV-1 clades are circulating in Argentina.