RESUMO
Leishmaniavirus is a double-stranded RNA virus that persistently infects some strains of the protozoan parasite Leishmania. There is considerable interest in the possibility that the presence of this virus alters parasite phenotype and may affect disease pathogenesis. If so, the virus marker could provide a valuable prognostic indicator for human leishmaniasis, particularly in those cases caused by New World parasite strains. The virus has been detected in cultured L. braziliensis, L. b. guyanensis, and L. major. To date there has been no information as to the extent of infection in samples prior to culturing in the laboratory. This study demonstrates, through the reverse transcription-polymerase chain reaction, that Leishmaniavirus exists in human biopsy samples of leishmaniasis prior to manipulation in culture.
Assuntos
Leishmaniose Cutânea/virologia , Leishmaniavirus/isolamento & purificação , Pele/virologia , Animais , Sequência de Bases , Biópsia por Agulha , Sequência Consenso , DNA Viral/análise , DNA Viral/química , Humanos , Leishmaniose Cutânea/etiologia , Leishmaniose Cutânea/patologia , Leishmaniavirus/genética , Leishmaniavirus/fisiologia , Dados de Sequência Molecular , Peru , Reação em Cadeia da Polimerase , RNA Viral/genética , Análise de Sequência de DNARESUMO
Leishmania braziliensis cells are difficult to culture in vitro and usually require media supplemented with serum for sustained cell division. Fresh, sterile urine is an inexpensive substitute for serum in the culture of 2 strains of L. braziliensis, 1 infected with Leishmania RNA virus 1, and 1 uninfected. In the presence of urine, both the infected and the uninfected strains grew to the same final cell density as the same strains grown in the presence of serum. One strain of Leishmania major was also successfully cultured in urine-supplemented media.
Assuntos
Leishmania braziliensis/crescimento & desenvolvimento , Urina , Animais , Divisão Celular , Meios de Cultura Livres de Soro , Humanos , Leishmania major/crescimento & desenvolvimento , MasculinoRESUMO
Viral particles purified from species of the protozoan parasite Leishmania braziliensis subsp. guyanensis by centrifugation in CsCl gradients were examined for the presence of viral polymerase. We demonstrated that RNA-dependent RNA polymerase is associated with viral particles. Viral transcription was studied in vitro with pulse-chase experiments and by assaying the RNase sensitivity of the viral transcripts. Viral polymerase synthesized full-length transcripts within 1 h. Double-strained, genome-length, and single-stranded RNAs were produced in this system. The nature of the RNA extracted from virions was also tested by RNase protection assays; both single-stranded and double-stranded RNAs were found.