Equatorial Guinea is endemic for HIV-1. This country borders to the north with Cameroon, where different subtypes belonging to group M, as well as group O strains, are circulating simultaneously. To assess the molecular epidemiology of HIV-1 in Equatorial Guinea we analyzed 76 plasma samples collected throughout 1999 from seropositive individuals. Phylogenetic analysis of the gp41 region revealed that 53 were of subtype A, with 64% of these sequences clustering with CRF02_AG reference strains; 11 were of subtype C; 4 were of subtype D; 2 (closely related to subtype F2) were of subtype F; 3 were of subtype G, two of them forming a separate cluster with the recombinant circulating forms CRF06_cpx; 1 was of subtype H; and 2 were unclassifiable. Although subtype A is predominant, the presence of 14% of subtype C is also noteworthy. This work represents the first HIV-1 subtype distribution study in Equatorial Guinea.
The cytotoxic effect of five flavonoids isolated from the aerial parts of the Asteraceae family of plants were studied in vitro using LLC-MK2 and C6 glial cells. Agehoustin A was shown to be cytotoxic for both cells (71% or 67% cell death). Agehoustin B and artemetin, which lack a methoxy group at C-8 (RI), were not cytotoxic for the cells (19% and 16% cell death). The three flavonoids showed considerable suppressive effects on LLC-MK2 and C6 cell growth. Lucidin-dimethylether and gnaphaliin were also not cytotoxic for cells but they had no suppressive effect on cell growth. The results show a structure-cytostatic activity relationship. We suggest that the methoxy group on C-8 and on the B ring are responsible for death cell.
Recent attention has focused on the geographic variation of dengue viruses, since major epidemies may follow introduction of a new virus strain into susceptible populations. We cloned and sequenced a very interesting Mexican isolate (200787/1983) which is antigenically unique by signature analysis with respect to all other dengue-2 topotype viruses. This strain is also unique in biological behavior (neurotropism) and is of epidemiological significance in Mexico. The dengue-2 Mexican isolate sequence information was compared with that of other flaviviruses, analyzing the branching structure of the phylogenetic tree reconstructed from the E gene amino acid sequences. The E glycoprotein, is target for neutralizing antibodies and T-cell responses, and defines the tropism and virulence of flaviviruses. In the phylogram, our strain was located in the position of greatest dissimilarity within serotype-2. Also, frequency analysis of amino acids revealed a very different signature pattern from that found in viral serotype-2.
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