Ultrastructure of the rotifer integument: peculiarities of Sinantherina socialis (Monogononta: Gnesiotrocha)

摘要: The rotifer integument is a well-described syncytium that contains an apical intracytoplasmic lamina (ICL) functions for both skeletal support and muscle insertion. To date, there limited information on the structure of in species Gnesiotrocha, diverse subclade Monogononta consists solitary, colonial, sessile, planktonic species. In this study, we examined ultrastructure colonial Sinantherina socialis to determine how it corresponds other monogononts. S. was broadly similar rotifers, consisting thickened glycocalyx, multilaminate ICL, syncytial epidermis. However, different several regards. ICL consisted three distinct layers from basal: layer 1 at least two electron-dense laminae; 2 matrix amorphous, material or fibrous; 3 varying thickness covered underlying syncytium. Significantly, formed ridge-and-groove like system finger-like projections across trunk surface has not been observed rotifers. A voluminous cytoplasm (up 3 μm thick) present beneath mostly electron lucent with few organelles. Bundles potential microtubules were scattered throughout We hypothesize serves as rotifer's sessile lifestyle, while external ridges may function texture-based deterrent predators, trap secretions species' defensive glands. Basally, epidermis highly folded bordered by thin basal separated plasmalemma blastocoel. Membrane-bound vesicles integument's are hypothesized secretion extracellular maintenance ICL.