title: F-actin distribution and function during sexual development in Eimeria maxima.
abstract: To determine the involvement of the actin cytoskeleton in macrogametocyte growth and oocyst wall formation, freshly purified macrogametocytes and oocysts were stained with Oregon Green 514 conjugated phalloidin to visualize F-actin microfilaments, while Evans blue staining was used to detect type 1 wall forming bodies (WFB1s) and the outer oocyst wall. The double-labelled parasites were then analysed at various stages of sexual development using three-dimensional confocal microscopy. The results showed F-actin filaments were distributed throughout the entire cytoplasm of mature Eimeria maxima macrogametocytes forming a web-like meshwork of actin filaments linking the type 1 WFBs together into structures resembling 'beads on a string'. At the early stages of oocyst wall formation, F-actin localization changed in alignment with the egg-shaped morphology of the forming oocysts with F-actin microfilaments making direct contact with the WFB1s. In tissue oocysts, the labelled actin cytoskeleton was situated underneath the forming outer layer of the oocyst wall. Treatment of macrogametocytes in vitro with the actin depolymerizing agents, Cytochalasin D and Latrunculin, led to a reduction in the numbers of mature WFB1s in the cytoplasm of the developing macrogametocytes, indicating that the actin plays an important role in WFB1 transport and oocyst wall formation in E. maxima.
authors: The iThree Institute, School of Medical and Molecular Biosciences,University of Technology Sydney,PO Box 123,Broadway,Sydney,New South Wales 2007,Australia.
authors: Sonja
authors: S
authors: Frölich
authors: The iThree Institute, School of Medical and Molecular Biosciences,University of Technology Sydney,PO Box 123,Broadway,Sydney,New South Wales 2007,Australia.
authors: Michael
authors: M
authors: Wallach
mesh_terms: D008841:Actin Cytoskeleton / Q000648:ultrastructure; D000199:Actins / Q000737:chemistry / Q000502:physiology*; D000818:Animals; D001692:Biological Transport; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002473:Cell Wall / Q000187:drug effects / Q000648:ultrastructure; D002645:Chickens / Q000469:parasitology; D015638:Cytochalasin D / Q000494:pharmacology; D004539:Eimeria / Q000187:drug effects / Q000254:growth & development* / Q000648:ultrastructure; D008018:Life Cycle Stages / Q000187:drug effects / Q000502:physiology*; D018613:Microscopy, Confocal; D033661:Oocysts / Q000187:drug effects / Q000254:growth & development* / Q000648:ultrastructure; D015800:Protozoan Proteins / Q000737:chemistry / Q000502:physiology*; D046468:Sexual Development / Q000187:drug effects; D013194:Staining and Labeling; D053778:Thiazolidines / Q000494:pharmacology
chemical_list: D000199:Actins; D019086:Bridged Bicyclo Compounds, Heterocyclic; D015800:Protozoan Proteins; D053778:Thiazolidines; D015638:Cytochalasin D; C037067:latrunculin A
keywords:  Eimeria oocyst; 3D confocal microscopy; WFB1 vesicle transport; actin; cytoskeletal inhibitors