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K Reichel

Publications and source records attributed to K Reichel.

At least 37 records · Page 2Linked to original sources
PubMed1980

Genetic dissection of the final exocytosis steps in Paramecium tetraurelia cells: cytochemical determination of Ca2+-ATPase activity over performed exocytosis sites.

In different Paramecium tetraurelia strains the occurrence of a Ca2+-ATPase (or p-nitro-phenylphosphatase) activity at the preformed attachment and exocytosis sites of the secretory vesicles (trichocysts) was analysed by electron-microscopic cytochemistry and X-ray microanalysis. In conjunction with freeze-fracture studies it was found that only those strains, which contain rosette particles, display this Ca2+-ATPase activity (7S, K 40I, nd 9 (18 degrees C), while other strains (nd 6, nd 9 (27 degrees C), tam 38) are devoid of both these characteristics. The presence (absence) of rosette particles and of Ca2+-ATPase activity at the preformed exocytosis sites is correlated with the capability (incapability) of performing exocytosis in these strains. We discuss several possible interpretations of this structure-function correlation.

Animals↗
PubMed1980

Genetic dissection of the final exocytosis steps in Paramecium tetraurelia cells: trigger analyses.

A variety of trigger procedures were applied to analyse the exocytotic capability of different Paramecium tetraurelia strains. 7,S K 40I, kin 24I, and 9 (18 degrees C) are capable of exocytosis (permissive strains), in contrast to nd 6, nd 7, nd 9 (27 degrees C), tam 38 and ftb A, although all procedures used enhance [Ca2+]i in the cytoplasm of all strains tested and although strains nd 6, nd 7 and nd 9 (27 degrees C) contain a full set of morphologically normal trichocysts attended to the cell membrane. The results show that only those strains are permissive which were shown previously to contain a rosette of membrane-integrated particles and a Ca2+-ATPase activity in the cell membrane over the trichocyst attachment (exocytosis) sites. The results from trigger experiments with permissive and non-permissive strains would be compatible with a dual function of rosette particles as Ca2+ pumps and Ca2+ channels. Nevertheless, the latter aspect remains uncertain since we show that experiments along these lines published by others (introducing a Ca2+ ionophore from the outside) involve a solvent-induced artifact (pseudoexocytosis: matrix stretching in the absence of membrane fusion). In all strains, except for tam 38 and ftb A (which have abnormal trichocysts incapable of being attached to the cell membrane), the isolated trichocyst matrix can be transferred from the contracted to the expanded state in vitro with certain trigger procedures. Our data clearly show that an increase of [Ca2+]i in the cytoplasm is not sufficient for exocytosis to occur and that non-permissiveness is somehow due to an inability to perform membrane fusion. It remains open whether the lack of rosettes and Ca2+-ATPase activity at trichocyst attachment sites are primary cause of non-permissiveness.

Animals↗
PubMed1979

[Multilocular Paget's disease--a case report (author's transl)].

The simultaneous occurrence of Paget's disease in five different regions in a 76-year old woman is reported. Only one lesion exhibited the typical clinical appearance of this condition, whereas the others were diagnosed histologically. After radical surgical treatment of all lesions the patient has remained free from recurrence for more than three years.

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