Esta revisão destaca aspectos dos estágios do desenvolvimento de Trypanosoma cruzi e Trypanosoma rangeli em seu hospedeiro invertebrado, Rhodnius prolixus Atenção especial é dada às interações desses parasitas com moléculas presentes no tubo digestivo e na hemolinfa e efeitos da organização das células epiteliais sobre o desenvolvimento do parasita. A susceptibilidade do inseto vetor ao T. cruzi, o qual desenvolve no tubo digestivo, dependem do estado nutricional do hospedeiro, da cepa do parasita e de interações moleculares com compostos tripanolíticos, lectinas e bactérias residentes no tubo digestivo. O T. rangeli invade a hemocele e pode ser reconhecido e ativar o sistema de defesa do inseto vetor, ou seja, o sistema profenoloxidase, fagocitose, microagregação hemocitária,atividade de superóxido e óxido nítrico e a via de biossíntese dos eicosanóides. Estes fatos fornecem uma compreensão melhor das interações parasita-inseto vetor, e também oferecem novas idéias sobre os processos básicos envolvidos na transmissão parasitária.

This review outlines aspects on the developmental stages of Trypanosoma cruzi and Trypanosoma rangeli in the invertebrate host, Rhodnius prolixus. Special attention is given to the interactions of these parasites with gut and hemolymph molecules and the effects of the organization of midgut epithelial cells on the parasite development. The vector insect's permissiveness to T. cruzi, which develops in the vector gut, largely depends on the host nutritional state, the parasite strain and the molecular interactions with trypanolytic compounds, lectins and resident bacteria in the gut. T. rangeli invades the hemocoel and once in the hemolymph, can be recognized and activates the defense system of its insect vector, i.e., the prophenoloxidase system, phagocytosis, hemocyte microaggregation, superoxide and nitric oxide activity and the eicosanoid biosynthesis pathway. Taken together, these findings not only provide a better understanding of the interactions parasite - insect vector, but also offer new insights into basic physiological processes involved in the parasites transmission.

Este artigo traz a discussão sobre genética molecular em saúde ao campo da saúde pública. Com a revolução produzida pela chegada da engenharia genética, é importante discutir alguns dos avanços e problemas desta tecnologia para a sociedade. Está na hora de se fazer uma avaliação clara e bem informada acerca do que já se conseguiu e do que ainda podemos conseguir através desta tecnologia. A sociedade precisa compreender as implicações éticas e práticas de uma tecnologia capaz de produzir drogas milagrosas, dagnósticos modernos e a cura de todas as doenças. Alguns pontos particularmente delicados pertinentes às questões sociais ligadas à biologia molecular e ao projeto genoma humano são discutidos.

This article is an attempt to draw the discussion on molecular genetics in health into the public health domain. Now that the genetic engineering revolution has arrived, it is important to point out the advances and problems this technology poses for society. It is time for a clear, informed assessment of what we have already achieved and may soon achieve using this technology. Clearly, society needs to understand the ethical and practical implications of a technology which can produce miracle drugs and modern diagnoses and cure virtually every disease. Important points from sensitive social issues raised by molecular biology and the human genome project are discussed.

Este artigo traz a discussão sobre genética molecular em saúde ao campo da saúde pública. Com a revolução produzida pela chegada da engenharia genética, é importante discutir alguns dos avanços e problemas desta tecnologia para a sociedade. Está na hora de se fazer uma avaliação clara e bem informada acerca do que já se conseguiu e do que ainda podemos conseguir através desta tecnologia. A sociedade precisa compreender as implicações éticas e práticas de uma tecnologia capaz de produzir drogas milagrosas, dagnósticos modernos e a cura de todas as doenças. Alguns pontos particularmente delicados pertinentes às questões sociais ligadas à biologia molecular e ao projeto genoma humano são discutidos.

This article is an attempt to draw the discussion on molecular genetics in health into the public health domain. Now that the genetic engineering revolution has arrived, it is important to point out the advances and problems this technology poses for society. It is time for a clear, informed assessment of what we have already achieved and may soon achieve using this technology. Clearly, society needs to understand the ethical and practical implications of a technology which can produce miracle drugs and modern diagnoses and cure virtually every disease. Important points from sensitive social issues raised by molecular biology and the human genome project are discussed.

A study of the phagoinhibitor and anti-moulting activities of the Brazilian Melia azedarach, collected in the state of Rio de Janeiro, Brazil, allowed the isolation of four lignanes identified as pinoresinol, bis-epi-pinoresinol, the hemicetal and the diacid. These substances are devoid of anti-moulting activity.

Este artigo apresenta a importância da biodiversidade, da biotecnologia a da saúde e discute vários aspectos dos problemas biológicos, ambientais e o dilema ético, relacionados com a expansão e a exploração dos recursos naturais em razão das quais espécies de plantas e animais têm sido extintas. Por outro lado, o conhecimento da biodiversidade tem possibilitado a identificação e a utilização de novos recursos naturais para a melhoria da vida do homem neste planeta. É importante que nossos pesquisadores se envolvam na luta pela preservação do ecossistema tropical. Os programas de exploração da biodiversidade devem estar baseados em sólidos conhecimentos científicos e favorecer ecológica e economicamente a sociedade.

This article presents the significance of biodiversity, biotechnology and health and discusses many aspects of biological and environmental problems as well as the ethical dilemma related to expansion and exploitation of natural resources, which promoted a decline in biological diversity. In addition, knowledge of biodiversity has allowed for identification and use of new natural resources, useful for improving the quality of human life on Earth. It is important that our researchers engage themselves in the fight for preservation of the tropical ecosystem. Programs to exploit biodiversity must be based on solid scientific knowledge and favour society both ecologically and economically.

Este artigo apresenta a importância da biodiversidade, da biotecnologia a da saúde e discute vários aspectos dos problemas biológicos, ambientais e o dilema ético, relacionados com a expansão e a exploração dos recursos naturais em razão das quais espécies de plantas e animais têm sido extintas. Por outro lado, o conhecimento da biodiversidade tem possibilitado a identificação e a utilização de novos recursos naturais para a melhoria da vida do homem neste planeta. É importante que nossos pesquisadores se envolvam na luta pela preservação do ecossistema tropical. Os programas de exploração da biodiversidade devem estar baseados em sólidos conhecimentos científicos e favorecer ecológica e economicamente a sociedade.

This article presents the significance of biodiversity, biotechnology and health and discusses many aspects of biological and environmental problems as well as the ethical dilemma related to expansion and exploitation of natural resources, which promoted a decline in biological diversity. In addition, knowledge of biodiversity has allowed for identification and use of new natural resources, useful for improving the quality of human life on Earth. It is important that our researchers engage themselves in the fight for preservation of the tropical ecosystem. Programs to exploit biodiversity must be based on solid scientific knowledge and favour society both ecologically and economically.

The effects of azadirachtin, a tetranortriterpenoid from the neem tree Aradirachta indica J. on both immunity and Trypanosoma cruzi interaction within Rhodniusprolixus and other triatomines, were presented Given through a blood meal, azadirachtin affected the immune reactivity as shown by a significant reduction in numbers of hemocytes and consequently nodule formation follwing challenge with Enterobacter cloacae ß12, reduction in ability to produce antibacterial activities in the hemolymph when injected with bacteria, and decreased ability to destroy the infection caused by inoculation of E. cloacae cells. A single dose of azadirachtin was able to block the development of T. cruzi in R. prolixus if given through the meal at different intervals, together with, before or after parasite infection. Similary, these results were observed with different triatomine species and different strains of T. cruzi. Azadirachtin induced a permanent resistance of the vector against reinfection with T. cruzi. The significance of these data is discussed in relation to the general mode of azadirachtin action in insects.

The objective of this work was to characterize, and compare different morphological types of hemocytes of Rhodnius prolixus, Rhodnius, Rhodnius neglectus, Triatoma infestans, Panstrongylus megistus, and Dipetalogaster maximus. This information provides the basis for studying the cellular immune systems of these insects. Seven morphological hemocyte types wereidentified by phase-contrast microscopy: prohemocytes, plasmatocytes, granular cells, cytocytes, oenocytoids, adipohemocytes and giant cells. All seven types of hemocytes are not present in every species. For example, adipohemocytes and oenocytoids were not observed in P. megistus and P. infestans, and giant cells were rarely found in any of the species studied. The hemocytes of rhodnius and Dipetalogaster are more similar to each other than those from Triatoma and Panstrongylus which in turn closely resemble each other. Emphasis is placed on methodological problems arising in this work wicah are discussed in detail.

Proallatotoxins, and particularly preconcenes, are exceptionally promising models for studying Rhodnius prolixus physiology and for comparison with other natural compounds with anti-hormonal activities. Effects of preconcenes on feeding, development and reproduction of R. prolixus are being detailed. The precocenes reveal significant effects on feeding, moulting cycle (inducing precocious metamorphosis and ecdysial stasis), and reproduction of these insect. The mechanism of action of proallatotoxins was discussed based on the corpus allatum cytotoxic effect and on the ecdysteroid biosynthesis in prothoracic glands and ovaries. Further studies of these compounds on R. prolixus are need and will hopefully reveal other unesplored points regarding the action of the proallatotoxins on insects.

Azadirachtin A was given through a blood meal to 4th-instar larvae and to adult females of Rhodnius prolixus. Development (ecdysis) and egg production were inhibited in a dose-dependent manner. Long-term experiments with subsequent four feedings on azadirachtin-free blood were performed with 4th-instar larvae and with adult females. Only in the low-dose azadirachtin larval groups (0.01 and 0.1 microng/ml of blood), development was partially restored; after a single 1.0 microng/ml treatment about 50% of the treated larvae were still alive 120 days later without any adult emergence. Similarly fed females had a dose-dependent lower survival and egg deposition rate. The results are discussed in relation to the mode of azadirachtin A action.