P. Ropstorf et al., COMPARATIVE FINE-STRUCTURAL INVESTIGATIONS OF INTERPHASE AND MITOTIC NUCLEI OF VAMPYRELLID FILOSE AMEBAS, The Journal of eukaryotic microbiology, 41(1), 1994, pp. 18-30
The nuclei of trophozoites and digestive cysts as well as mitotic nucl
ei of several species of the vampyrellids Vampyrella, Gobiella, Hyalod
iscus, Arachnula, and Leptophrys were investigated by electron microsc
opy. Except for some species of the genus Hyalodiscus, the vampyrellid
s are generally multinucleate. The nuclei of the trophozoite stage are
in interphase. These nuclei are spherical, except for the genus Arach
nula, which reveals elongated nuclei. In digestive cysts of all vampyr
ellids the nuclei enlarge and the pars granulosa of the nucleoli becom
es prominent. Karyokineses take place synchronously in older digestive
cysts, which transform into reproductive cysts. The nuclei divide by
closed intranuclear orthomitosis. In telophase the old nuclear envelop
e disintegrates and a new one is rearranged. Only in the genus Leptoph
rys the nuclear envelope decomposes before telophase. Neither centriol
es nor MTOC-plaques have been found in any stage of mitosis. After kar
yokinesis the cell divides inside the cyst or when leaving the cyst.