Paramecium tredecaurelia of the Paramecium aurelia complex in Israel

The paper concerns the finding of a new habitat (Kiryat Motzkin, north of Haifa, Israel) of Paramecium tredecaurelia from the P. aurelia complex. This is only the forth known locality of the species in the world. Previously, its strains were obtained from widely separated localities: the River Seine, Paris, France; Benenitra, Madagascar, and the Cuernavaca Valley, Taxco, Mexico. The studied strain originating from Israel was identified as P. tredecaurelia on the basis of the strong (90%) conjugation between the complementary mating type of the examined clones with the appropriate standard strain 209 of P. tredecaurelia from Paris, France (restricted to odd mating type). However, the strain from Israel is restricted to the even mating type.     

Paramecium sexaurelia of the Paramecium aurelia species complex in Thailand

The clones originating from Thailand, Phuket Island, were identified as Paramecium sexaurelia.     

The Paramecium aurelia species complex in Ukraine

New habitats of Paramecium biaurelia were found in the Gorgany Mts, Eastern Carpathians.     

Divalent cation affinity sites in Paramecium aurelia

Sites with high calcium affinity in Paramecium aurelia were identified by high calcium (5 mM) fixation and electron microscope methods. Electron-opaque deposits were observed on the cytoplasmic side of surface membranes, particularly at the basal regions of cilia and trichocyst-pellicle fusion sites. Deposits were also observed on some smooth cytomembranes, within the axoneme of cilia, and on basal bodies. The divalent cations, Mg2+, Mn2+, Sr2+, Ni2+, Ba2+, and Zn2+, could be substituted for Ca2+ in the procedure. Deposits were larger with 5 mM Sr2+. Ba2+, and Mn2+ at ciliary transverse plates and the terminal plate of basal bodies. Microprobe analysis showed that Ca and C1 were concentrated within deposits. In some analyses, S and P were detected in deposits. Also, microprobe analysis of 5 mM Mn2+-fixed P. aurelia showed that those deposits were enriched in Mn and C1 and sometimes enriched in P. Deposits were seen only when the ciliates were actively swimming at the time of fixation. Locomotory mutants having defective membrane Ca-gating mechanisms and ciliates fixed while exhibiting ciliary reversal showed no obvious differences in deposition pattern and intensity. Possible correlations between electron-opaque deposits and the locations of intramembranous particles seen by freeze-fracture studied, as well as sites where fibrillar material associate with membranes are considered. The possibility that the action sites of calcium and other divalent cations were identified is discussed.     

Interspecies transfer of mitochondria in Paramecium aurelia.

Summary Erythromycin-resistant mitochondria from species 1, 5 and 7 of P. aurelia were injected into erythromycin-sensitive paramecia of each of the same three species. Mitochondria from species 1 and 5 were successfully transferred to all three species, but species 7 mitochondria failed to develop in species 1 and 5. Minor differences were indicated in the frequency of successful transfers of species 1 mitochondria into species 1 and 5 cells. From studies on the transferability of mitochondria from hybrid cells, containing mitochondria from one species and nuclei from another, it was concluded that mitochondrial compatibility was mainly under control of the nuclear genome, with a possible minor control also by the mitochondrial genome.Dedicated to T.M. Sonneborn on the occasion of his seventieth birthday. This paper is part of a Sonneborn Festchrift most of which will appear in Genetical Research in 1976.