Ref ID : 4831
Hans-Werner Kuhlmann; Giants in Lembadion bullinum (Ciliophora, Hymenostomata) - General Morphology and Inducing Conditions. Arch.Protistenk 143:325-336, 1993
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The freshwater hymenostome Lembadion bullinum exists in two forms: "normal" cells and "giants". The general morphology of both morphotypes was studied, biometrical data for both morphs are presented and compared with each other. Beside a shape increase in cell length and width, giants are characterized by their larger oral region, by an increased number of meridional kineties, by a larger macronucleus and in certain stocks by the occurrence of additional micronuclei. It is shown that the majority of giants present in a culture originates in binary fission of already transformed cells. The ex novo transformation of normal cells into giants regularly occurred in starved cultures as a consequence of cannibalism. At higher cell densities (>/_250 cell/ml) relatively more individuals transformed into giants that at low cell densities (< /_50 cells/ml). There is no evidence for any soluble or cell bound "giant inducing factor" in this species.