RESUMO
Epimastigotes multiplies in the insect midgut by taking up nutrients present in the blood meal including heme bound to hemoglobin of red blood cell. During blood meal digestion by vector proteases in the posterior midgut, hemoglobin is clipped off into amino acids, peptides, and free heme. In this paper, we compared the heme and hemoglobin uptake kinetics and followed their intracellular trafficking. Addition of heme to culture medium increased epimastigote proliferation in a dose-dependent manner, while medium supplemented with hemoglobin enhanced growth after 3-day lag phase. Medium supplemented with globin-derived peptides stimulated cell proliferation in a dose-independent way. Using Palladium mesoporphyrin IX (Pd-mP) as a fluorescent heme-analog, we observed that heme internalization proceeded much faster than that observed by hemoglobin-rhodamine. Binding experiments showed that parasites accumulated the Pd-mP into the posterior region of the cell whereas hemoglobin-rhodamine stained the anterior region. Finally, using different specific inhibitors of ABC transporters we conclude that a P-glycoprotein homologue transporter is probably involved in heme transport through the plasma membrane.
Assuntos
Heme/metabolismo , Trypanosoma cruzi/fisiologia , Sequência de Aminoácidos , Ciências da Nutrição Animal , Animais , Transporte Biológico , Galinhas , Meios de Cultura , Endocitose , Globinas/metabolismo , Mesoporfirinas/farmacocinética , Modelos Biológicos , Dados de Sequência Molecular , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/farmacocinéticaRESUMO
OBJECTIVE: The survey "Mortality 2000" had for aim to describe the distribution of causes of death in HIV-infected adults in France. METHOD: Hospital wards involved in the management of HIV infection prospectively reported deaths occurring in 2000. The causes of death were documented using a standardized questionnaire. RESULTS: In French Guyana and the French West Indies the five referent wards reported 81 deaths. The main underlying causes of death were AIDS-related (67%), non-AIDS and non-hepatitis related cancer (9%), cardiovascular disease (7%), bacterial infections (5%), and end stage liver disease (4%). Among AIDS-related deaths, the more frequent diseases were histoplasmosis and toxoplasmosis in Guyana and atypical mycobacterial infection, tuberculosis, and cytomegalovirus disease in the West Indies. Median age was 43 years, transmission of HIV infection was heterosexual in 79%; 56% lived in poor socio-economic conditions, and 30% were born abroad. One out of five had been recently diagnosed with HIV infection and one out of three had never received antiretroviral treatment. CONCLUSION: In 2000, two in three death cases in HIV-infected adults were AIDS-related in French Guyana and the French West Indies. Improved strategies for screening HIV infection before the occurrence of AIDS are still needed taking into consideration poor socio-economic and migrant conditions.
Assuntos
Infecções por HIV/mortalidade , Adulto , Terapia Antirretroviral de Alta Atividade , Causas de Morte , Feminino , Guiana Francesa , Infecções por HIV/tratamento farmacológico , Humanos , Masculino , Estudos Prospectivos , Estatísticas VitaisRESUMO
In eukaryotes, proteins homologous to the bacterial DnaJ protein are involved in regulation of the Hsp70 molecular chaperones, which are implicated in a variety of protein biogenesis pathways. We report herewith the molecular characterization of a T. cruzi DnaJ gene, termed TcJ6, encoding a protein that displays high sequence homology with the Saccharomyces cerevisiae Sis1 co-chaperone required for the initiation of translation. TcJ6 protein was expressed as a polypeptide of 36.5 kDa at a constant level during parasite differentiation and was associated to the cytoplasmic fraction. We showed that overexpression of TcJ6 complemented a temperature-sensitive yeast sis1 mutant. In addition, sucrose gradient sedimentation analysis of polysomes from T. cruzi and a yeast mutant overexpressing TcJ6p showed that the trypanosomal co-chaperone was closely associated with ribosomal subunits, 80 S monosomes and the smaller polysomes, as observed for Sis1p. Furthermore, in T. cruzi TcJ6p was also found to be preferentially concentrated around the nucleus, giving a speckled staining pattern. This suggests that TcJ6p is associated with the endoplasmic reticulum. Taken together, these data suggest that the trypanosomal DnaJ is involved in initiation of translation.
Assuntos
Proteínas de Choque Térmico/fisiologia , Fatores de Iniciação de Peptídeos/fisiologia , Biossíntese de Proteínas/fisiologia , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Trypanosoma cruzi/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Primers do DNA , Proteínas de Choque Térmico HSP40 , Proteínas de Choque Térmico/química , Dados de Sequência Molecular , Fatores de Iniciação de Peptídeos/química , Fenótipo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Homologia de Sequência de AminoácidosRESUMO
The allele frequency distribution of two highly polymorphic DNA sequences was determined in a population from the metropolitan area of Fortaleza (Northeast Brazil). DNAs from 234 individuals were digested with Pvull and successively hybridized to each probe: alpha-Globin 3'HVR and Mucin HVR. The resulting allele frequencies were compared to those observed in a French population. There is no statistically significant difference between these populations in the 3'HVR system. On the contrary, the distribution is statistically different in the Mucin HVR/Pvull system.
Assuntos
DNA/genética , Frequência do Gene/genética , Polimorfismo Genético/genética , Alelos , Brasil , França , HumanosRESUMO
DNAS from 325 individuals representing 2 different populations (234 Brazilians and 91 Asiatics) were analysed for Restriction Fragment Length Polymorphisms (RFLPs). These DNAs were digested with Pvu II enzyme and successively hybridized to two HVR probes: alpha globin-3'HVR and Mucin-HVR. An allele frequency distribution was determined for each couple probe/enzyme and each ethnic groupe studied. The results were compared with frequencies observed in french population and we showed that there is no statistic significant difference between allele frequencies obtained with the couple probe/enzyme 3'HVR/Pvu II in Brazilian and French populations. We also showed that both populations studied (Brazilian and Asiatic) do not follow a Hardy-Weinberg balance.