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From the cell biology to the development of new chemotherapeutic approaches against trypanosomatids: dreams and reality.

De Souza W - Kinetoplastid Biol Dis (2002)

Bottom Line: These organisms are also of biological interest since they are able to change the morphology according to the environment where they live, through a process of reversible cell transformation, and possess structures and organelles that are not found in mammalian cells.In addition, the present knowledge of structures and organelles such as the nucleus, the plasma membrane, the sub-pellicular microtubules, the flagellum, the kinetoplast-mitochondrion complex, the peroxisome (glycosome), the acidocalcisome and the structures and organelles involved in the endocytic pathway, is reviewed from a cell biology perspective.The possible use of available data for the development of new anti parasite drugs is also discussed.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, CCSBloco G, 21941900, Rio de JaneiroRJ, Brasil. wsouza@biof.ufrj.br

ABSTRACT
Members of the Trypanosomatidae family comprise a large number of species that are causative agents of important diseases such as sleeping sickness, Chagas' disease and Leishmaniasis. These organisms are also of biological interest since they are able to change the morphology according to the environment where they live, through a process of reversible cell transformation, and possess structures and organelles that are not found in mammalian cells. This review analyses the process of transformation, which takes place during the life cycle of Trypanosoma cruzi in the vertebrate and invertebrate hosts. Special attention is given to the interaction of the parasite with vertebrate cells. In addition, the present knowledge of structures and organelles such as the nucleus, the plasma membrane, the sub-pellicular microtubules, the flagellum, the kinetoplast-mitochondrion complex, the peroxisome (glycosome), the acidocalcisome and the structures and organelles involved in the endocytic pathway, is reviewed from a cell biology perspective. The possible use of available data for the development of new anti parasite drugs is also discussed.

No MeSH data available.


Related in: MedlinePlus

Different views of the membrane lining recem penetrated trypomastigote forms of T. cruzi.
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Figure 7: Different views of the membrane lining recem penetrated trypomastigote forms of T. cruzi.

Mentions: Subsequent to internalization, the trypomastigote gradually transforms into an intermediate epimastigote and then into an amastigote form. This process is characterized by the shortening of the flagellum and rounding of the cell body. During the trypomastigote-spheromastigote transformation there is an intermediary phase, which is designated as epimastigote, although this form is somewhat different from the epimastigote observed in axenic cultures. Two hours after penetration, a process of gradual lysis of the membrane lining the PV occurs (Fig. 7) [31] due the release of a trypsin-sensitive parasite enzyme known as TcTox [32]. This process depends on the existence of an acidic compartment and the nature of the components of the membrane. After the complete rupture of the PV membrane, the amastigote form establishes direct contact with the host cell cytoplasmic structures and organelles and after 24 to 35 hours starts to divide. The significance of this long lag period in the intracellular life cycle of T. cruzi is not yet completely understood but it is influenced by the growth temperature of the vertebrate cells. Autoradiographic studies indicates that DNA synthesis occurs during the lag period [33]. Using a special cell line of fibroblasts which, due to the loss of hypoxanthineguanine phosphoribosyltransferase, are unable to incorporate guanine into nucleic acids it was shown by autoradiography that parasite RNA synthesis occurs only 2 hours after the penetration of the parasite inside the vertebrate cell [34]. Therefore the synthesis of new RNA does not appear to be required for the process of trypomastigote-spheromastigote transformation. These studies also showed that extracellular trypomastigotes actively synthesize RNA.


From the cell biology to the development of new chemotherapeutic approaches against trypanosomatids: dreams and reality.

De Souza W - Kinetoplastid Biol Dis (2002)

Different views of the membrane lining recem penetrated trypomastigote forms of T. cruzi.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC119324&req=5

Figure 7: Different views of the membrane lining recem penetrated trypomastigote forms of T. cruzi.
Mentions: Subsequent to internalization, the trypomastigote gradually transforms into an intermediate epimastigote and then into an amastigote form. This process is characterized by the shortening of the flagellum and rounding of the cell body. During the trypomastigote-spheromastigote transformation there is an intermediary phase, which is designated as epimastigote, although this form is somewhat different from the epimastigote observed in axenic cultures. Two hours after penetration, a process of gradual lysis of the membrane lining the PV occurs (Fig. 7) [31] due the release of a trypsin-sensitive parasite enzyme known as TcTox [32]. This process depends on the existence of an acidic compartment and the nature of the components of the membrane. After the complete rupture of the PV membrane, the amastigote form establishes direct contact with the host cell cytoplasmic structures and organelles and after 24 to 35 hours starts to divide. The significance of this long lag period in the intracellular life cycle of T. cruzi is not yet completely understood but it is influenced by the growth temperature of the vertebrate cells. Autoradiographic studies indicates that DNA synthesis occurs during the lag period [33]. Using a special cell line of fibroblasts which, due to the loss of hypoxanthineguanine phosphoribosyltransferase, are unable to incorporate guanine into nucleic acids it was shown by autoradiography that parasite RNA synthesis occurs only 2 hours after the penetration of the parasite inside the vertebrate cell [34]. Therefore the synthesis of new RNA does not appear to be required for the process of trypomastigote-spheromastigote transformation. These studies also showed that extracellular trypomastigotes actively synthesize RNA.

Bottom Line: These organisms are also of biological interest since they are able to change the morphology according to the environment where they live, through a process of reversible cell transformation, and possess structures and organelles that are not found in mammalian cells.In addition, the present knowledge of structures and organelles such as the nucleus, the plasma membrane, the sub-pellicular microtubules, the flagellum, the kinetoplast-mitochondrion complex, the peroxisome (glycosome), the acidocalcisome and the structures and organelles involved in the endocytic pathway, is reviewed from a cell biology perspective.The possible use of available data for the development of new anti parasite drugs is also discussed.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, CCSBloco G, 21941900, Rio de JaneiroRJ, Brasil. wsouza@biof.ufrj.br

ABSTRACT
Members of the Trypanosomatidae family comprise a large number of species that are causative agents of important diseases such as sleeping sickness, Chagas' disease and Leishmaniasis. These organisms are also of biological interest since they are able to change the morphology according to the environment where they live, through a process of reversible cell transformation, and possess structures and organelles that are not found in mammalian cells. This review analyses the process of transformation, which takes place during the life cycle of Trypanosoma cruzi in the vertebrate and invertebrate hosts. Special attention is given to the interaction of the parasite with vertebrate cells. In addition, the present knowledge of structures and organelles such as the nucleus, the plasma membrane, the sub-pellicular microtubules, the flagellum, the kinetoplast-mitochondrion complex, the peroxisome (glycosome), the acidocalcisome and the structures and organelles involved in the endocytic pathway, is reviewed from a cell biology perspective. The possible use of available data for the development of new anti parasite drugs is also discussed.

No MeSH data available.


Related in: MedlinePlus