As a species of the epizootic ciliate, Apiosoma piscicola Blanchard, 1885 which attaches to the surfaces of many kinds of hydrobionts can badly endanger the hosts and cause great losses to the aquaculture industry. It also has a wide spread, such as Europe, Asia and South Africa. Because of its great variability in different regions, Apiosoma piscicola (Blanchard, 1885) has some synonyms such as "Glossatella cyprinid Sramek-Husek, 1953", "Apiosoma magna Banina, 1968", etc. In China, it was firstly reported by Chen with the name "Glossatella cylindriformis" in 1956. Although Apiosoma piscicola was found more than one century before, today our understanding to them remains in the stage of alpha taxonomy. In order to carry out the research deeply, the author collected numerous specimens from the gills and fins of the fishes that were heavily infected in the Hongze Lake of Jiangsu Province located in east of China. This paper systematically dealt with the morphology and structure of the living specimens( stained with 2% Neutral Red)and fixed-stained specimens(the smears fixed in saturated HgCl2 solution and stained with Heidenhain's haematoxylin, Ehrlich's haematoxylin and the dry smears impregnated in 3% AgNO3 solution)under optical microscopy and the ultrastructure under transmission electron microscopy. Great diversities have been found on the sizes of the organisms (the length and width of the body, macronucleus and micronucleus)compared with the data of Hupei specimens and the reason was discussed. In addition, lots of bacteria and food particles were observed within the body of the organisms, especially around the peristomial disc under transmission electron microscopy. This phenomenon gives a strong support from the aspect of food sources to the viewpoint that Apiosoma is a kind of ectocommensals but not ectoparasites.
Li Ming; Wang Jian-Guo; Zhang Jin-Yong; Zhu Da-Ling; Gu Ze-Mao; Gong Xiao-Ning.Observation on the Apiosoma piscicola under optical and transmission electron microscope,Acta Hydrobiologica Sinica,2007,31(2):208-213