Sphaeripara catenata
Diagnosis
Parasite of appendicularian (Fritillaria pellucida).
Young trophont (about 10 µm in diameter), located inside the mucus vacuole of the glandular cell in the ectoderm, is surrounded by a thin external membrane. An equatorial depression produces the episome and the hyposome, equivalent to what is observed in dinoflagellates. The nucleus is located in the episome, whilst the hyposome is used for feeding. The hyposome inserts inside the host cell cytoplasm, using fibers that helps in the adhesion of the parasite. Others retractable fibers penetrate deeply inside the host, reaching the internal face of the appidencularian tegument, inside the digestive anse and what will be the genital glands. A cytopharynx is produced, including of host material inside a digestive vacuole. Fibers may be used to feed by osmotrophy as well. The parasite remains inside the initial host cell, but this cell is considerably modified and becomes plurinucleated. During the same time, nuclei start to divide. They are regularly organized in several circular layers inside the episome. Divisions are not synchroneous; they are more frequent in the apical region of the episome. In the mature trophont, a constriction between two layers of nuclei will form a diaphragm which will separate in two the trophont. Same processus occur again in the apical constriction first, then in the basal unit, then again. The whole process has been called the metarization. The apical unit separates from the trophont and becomes spherical, and becomes a sporocyte. Several primary sporocytes (dozen) are successively formed, the last one will take away the last nucleus. The rest of the parasite stays inside its host. The mucus vacuole is destroyed during that process. Primary sporocytes, containing several nuclei arranged in layers, are freely distributed outside the host cell. Sporogenesis occur, and resulting cells are uninucleated and spherical (12 µm in diameter), and contain a vacuole in its center, resulting from the digestive vacuolve of the trophont. This vacuole disappears, a depression is formed from which two flagella are produced, one longitudinal, and the other is perpendicular and is surrounding the spore. Spores (8-10 µm) remained attached for a while, the compelte structure is able to swimm, but rapidly separate. Fate of these spores is unknown.
Sporogenesis does not kill the host, but its castration is often observed. Castration may occur when infection occurs very early during the host development (Cachon 1964).
Body_spores: 8-10 µm
Body_trophont: 12-130 µm
Type species
This is the type species of the genus.
Type illustration / Type locality / Type specimen
Type Host: Fritillaria pellucida.
Ecology
Substrate: endozoic
Sociability_adults: solitary
Salinity: marine
Life cycle
Generation: <1 month
Reproduction_mode: asexual
Feeding behaviour
Mode of locomotion
Reference(s)
Observation site(s)
HOSTS
Association with... | Region origin | Name of site | In reference... |
---|---|---|---|
Fritillaria pellucida | Villefranche-sur-mer | (1966) | |
Fritillaria pellucida | Villefranche-sur-mer |
Lohmania catenata nov. gen. nov. spec. . Biol. Centralblt 23:757-760. (1903) |
|
Fritillaria pellucida | Villefranche-sur-mer |
Uber Lohmanella catenata. Zeitschr. F. Wiss. Zool. 76:137-166. (1904) |
|
Fritillaria pellucida | Banyuls-sur-mer |
Sur un complexe xéno-parasitaire morphologique et physiologique, Neresheimeria catenata chez Fritillaria pellucida. C R Acad Sci Paris 121:55-57. (1920) |
|
Fritillaria pellucida | Villefranche-sur-mer |
Cycle évolutif et cytologie de Neresheimeria catenata Nereisheimer, péridinien parasite d'appendiculaires. Annales des Sciences Naturelles, Zoologie et Biologie Animale 12eme série:779-800. (1964) |