Pathogénie, cycle de développement et ultrastructure d'Amblyospora culicis n. sp. (Protozoa, Microspora), parasite du moustique Culex quinquefasciatus Say, 1823 (Diptera, Culicidae)

Abstract

R e p le I 1 septembre 1984 TOGUEBAYE, B. S., et B. MARCHAND. 1985. Pathogenie, cycle de developpement et ultrastructure d'Amblyospora culicis n. sp. (Protozoa, Microspora), parasite du moustique Culex quinquefasciatus Say, 1823 (Diptera, Culicidae). Can. J. Zool. 63: 1797 -1809. Amblyospora culicis n. sp. est une nouvelle microsporidie parasite du moustique Culex quinquefasciatus Say, 1823 (Diptera, Culicidae). Elle infeste les tissus adipeux et nerveux de larves et d'adultes des deux sexes, ainsi que les ovaires des femelles adultes. Les merontes observes presentent alternativement un, puis deux, diplocaryons constitues de noyaux diploi'des. La sporogonie est pansporoblastique et octosporee. Des merontes a un diplocaryon se transforment d'abord en presporontes entoures d'une paroi. Puis la membrane plasmique du presporonte se decolle de la paroi, realisant ainsi une vacuole pansporoblastique. Le presporonte s'entoure d'une nouvelle paroi, devenant ainsi un sporonte. Ses deux noyaux se separent, puis son cytoplasme se divise pour former deux sporontes uninuclees. Chacun d'eux subit alors deux divisions meiotiques. I1 en resulte la formation de huit sporontes uninuclees et haploi'des, qui evoluent en sporoblastes, puis en spores. Les spores sont ovoi'des, uninuclCCes et haploi'des (8,55 + 0,13 X 6,46 + 0,08 pm). Elles sont entourees par une paroi dont l'exospore est Cpaisse et complexe, et posskdent un filament polaire presentant une brusque constriction dans sa partie spiralee. TOGUEBAYE, B. S., and B. MARCHAND. 1985. Pathogenie, cycle de developpement et ultrastructure d'Amblyospora culicis n. sp. (Protozoa, Microspora), parasite du moustique Culex quinquefasciatus Say, 1823 (Diptera, Culicidae). Can. J. Zool. 63: 1797-1809. Amblyospora culicis n. sp. is a new microsporidian parasite of the mosquito Culex quinquefasciatus Say, 1823 (Diptera, Culicidae). It infects the adipose and nervous tissues of male and female larvae and adults, as well as the ovaries of adult females. The observed meronts have, in turn, one, then two diplokaryons constituted of diploid nuclei. The sporogony is pansporoblastic and octosporous. At first, diplokariotic meronts transform into diplokaryotic presporonts bounded by a wall. Then, the plasma membrane of the presporont detaches itself from the wall, thus creating a pansporoblastic vacuole. A new wall appears around the presporont which thus becomes a sporont. Its two nuclei separate from each other, then the cytoplasm divides to form two uninucleate sporonts. Each then undergoes two meiotic divisions which end in the formation of eight uninucleate and haploid sporonts. These sporonts evolve into sporoblasts, then into spores. The spores are ovoid, uninucleate, and haploid (8.55 ? 0.13 X 6.46 ? 0.08 pm). They are bounded by a wall having a thick multilayered exospore and contain a polar filament abruptly constricted in its coiled part.

Morphologic changes in Nosema algerae (Microspora) during extrusion

“…He could demonstrate the presence of a self-assembling protein in the polar tube and suggested that it could cause the rapid growth of the tube tip after extrusion. The structure of the polar tube has also been extensively documented (Lom 1972;Toguebaye and Marchand 1985;Canning and Holister 1987;Larsson et al 1993Larsson et al , 1995. The generally accepted morphology of the polar tube is the iso®lar nonmembranous six-layered structure in the coiled part.…”