| one publication added to basket [59115] | Étude ultrastructurale des bactéries épizoiques et endozoiques de Kentrophoros latum Raikov, cilié holotriche mésopsammique
Raikov, I.B. (1974). Étude ultrastructurale des bactéries épizoiques et endozoiques de Kentrophoros latum Raikov, cilié holotriche mésopsammique. Cah. Biol. Mar. 15(3): 379-393, 4 plates
In: Cahiers de Biologie Marine. Station Biologique de Roscoff: Paris. ISSN 0007-9723; e-ISSN 2262-3094, more
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| Keywords |
Kentrophoros latum Raikov, 1962 [WoRMS]
Marine/Coastal |
| Abstract |
Ribbon-shaped marine psammophilic ciliates K. latum, taxonomically related to the Loxodidae but mouthless, carry numerous epizoic sulphur bacteria on their non-ciliated 'dorsal' (morphologically left) body side. These obligatory epizoic bacteria are oblong, attached to the host in a brush-like manner, and covered with 2 unit membranes. (plasma membrane and cell wall membrane).This distinguishes them from the epizoic bacteria of K. fistulosum which have only one surface membrane (the plasma membrane).Microorganisms resembling spirochaetes but devoid of fibres in the space between the protoplast and the outer envelope occur among the sulphur bacteria. Epizoic bacteria are phagocytized by the ciliate at any place of its non-ciliated body side, but preferentially at the bottom of numerous pellicular folds. They get afterwards into food vacuoles, localized mainly in the median cytoplasmic swelling, and there become reduced to whirls of bacterial membranes. This appears to be the main mode of nutrition of K. latum. The endoplasm of certain individuals of K. latum contains rounded bacteria, covered also with 2 membranes, which lie groupwise in cytoplasmic vacuoles and are clearly different from ingested epizoic bacteria. The endozoic bacteria contain no sulphur and reproduce by binary fission. Some of these bacteria, which resemble the rickettsiae, become isolated by the host into smaller vacuoles where they gradually degenerate. These secondary vacuoles are always associated with mitochondria, unlike the food vacuoles containing epizoic sulphur bacteria. It is supposed that this degeneration is not a form of digestion. |
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