Isolation of a laccase with HIV-1 reverse transcriptase inhibitory activity from fresh fruiting bodies of the Lentinus edodes (Shiitake mushroom).

A laccase with a molecular mass of 67 kDa and inhibitory activity toward HIV-1 reverse transcriptase (IC50 = 7.5 M) was isolated from fresh fruiting bodies of the Lentinus edodes (Shiitake mushroom). Its characteristics were compared with those of laccases from cultured mushroom mycelia reported earlier. The laccase was unadsorbed on DEAE-cellulose, Affi-gel blue gel and CM-cellulose, but was adsorbed on Con A-Sepharose. About 50-fold purification was achieved with a 19.2% yield of the enzyme. The activity of the enzyme increased steadily from 20°C to 70°C. The activity disappeared after exposure to the boiling temperature for 10 min. Its optimal pH was 4 and very little enzyme activity remained at and above pH 10. The laccase inhibited HIV-1 reverse transcriptase with an IC50 of 7.5 M, but did not demonstrate any antifungal or anti-proliferative activity.

Prevalence of HIV-1 polymerase gene mutations in pre-treated patients in Thailand.

To determine the prevalence of drug resistance-conferring mutations in human immunodeficiency virus type 1 (HIV-1), 83 HIV-1 infected Thai patients who had been treated with any antiretroviral drug were studied. HIV-1 RNA was reverse transcribed and amplified by RT-PCR. The direct sequencing of HIV-1 reverse transcriptase (RT) and protease was then performed. Changes in nucleotide and amino acid sequences were determined by comparison with a pNL4-3 reference sequence. Data on mutations associated with resistance to antiretroviral drugs were obtained from literature. The mutations associated with lamivudine resistance (M184V/I) were found most often (in 45.7% of individuals). Zidovudine-resistant mutants: T215Y/F (36%), M41L (28%) and K70R (25.3%) were common; but mutations linked to didanosine (L74V) and multinucleoside-resistant genotypes (Q151M) were rarely recognized (2.4% and 3.6%, respectively). The stavudine-resistant mutant (V75T) and T69 insertions were not found. All subjects who had a significant exposure to antiretroviral drugs and current virological failure in the past carried drug-resistant genotypes. Genotypic resistance to zidovudine, lamivudine, zalcitabine, indinavir and ritonavir appeared in more than one third of the samples, which suggested that the prevalence of the HIV-1 resistance-conferring genotype resisting reverse transcriptase inhibitors and/or protease inhibitors was high in treatment experienced patients.

Inibiçäo seletiva das atividades das enzimas transcriptase reversa do vírus HIV-1 e DNA polimerases humanas por derivados dipirazolo-piridina / Selective inhibition of reverse transcriptase enzyme activity of HIV-1 virus and human polymerases DNA by dipirazolo-pyridines derivatives

Novos ribonucleosídeos derivados dos sistemas dipirazolo-piridina foram preparados e avaliados quanto à atividade polimerásica das enzimas transcriptase reversa (RT) do vírus HIV-1 e das DNA polimerases humanas alfa e epsilon. Os derivados 1b e 1d inibiram a atividade da transcriptase reversa em concentraçöes de micromolares. Entretanto, as mesmas substâncias näo foram capazes de inibir a atividade polimerase das enzimas DNA-polimerase humana alfa e epsilon.

Presença do HIV-1 e HIV-2 no Brasil: perspectivas epidemiológicas / The presence of HIV-1 and HIV-2 in Brazil: epidemiologic perspectives

Em março de 1984 foram realizados, pela primeira vez, no Brasil, inquéritos sorológicos reveladores da presença do HIV-1 (Tabela 1). Em meados de 1986 foram detectados, pela primeira vez, nas Américas, em Säo Paulo, quatro amostras de sangue positivas para o HIV-2 e 28 amostras positivas para ambos os vírus HIV-1 e HIV-2. Cerca de 5.000 casos de AIDS foram notificados até dezembro de 1988, estimando-se em 10 a 15.000 o número real de casos no Brasil. Apresentamos a evoluçäo histórica da origem e disseminaçäo do vírus HIV-2, da Africa para a Europa e América, especulando-se sobre a possível rota, Africa-Brasil do HIV-2. A previsäo sobre a evoluçäo da epidemia de AIDS no Brasil, e por extensäo no Terceiro Mundo, é pessimista, inclusive com a provável imitaçäo do modelo epidemiológico africano da AIDS no País. Além das repercussöes na economia local, säo previstas alteraçöes na patogenia e patologia de várias enfermidades endêmicas da regiäo, tais como Esquistossomose, Doença de Chagas, Tuberculose, Hanseníase, Lishamaniose Viceral, Sarampo, entre outras. Tais alteraçöes säo previstas, em virtude do papel relevante da imunidade mediada por células na evoluçäo das mencionadas doenças