A lysozyme-detergent method was developed for the fractionation of sporulating cells of B. subtilis 168 wild type into mother cell and forespore fractions. The method is very mild and is reproducible with optimum concentrations of Brij-58, deoxycholic acid and sucrose. The results were confirmed by application of the method to temperature sensitive mutants. Ts-1 and Ts-3. The amounts of proteins, and the activities of protease, alkaline phosphatase and glucose dehydrogenase were about 55, 56, 91, and 40%, respectively, in the mother cell fraction, and about 45, 44, 9, and 60%, respectively, in the forespore fraction, taking the totals for the combined fractions as 100%. Slab gel electrophoretic patterns indicated that many species of proteins with different molecular weights were present in the two fractions. Pulse-labeling with [3H]UTP was carried out in vivo at stage III, and 35.2 and 64.8% of the [3H]UMP incorporated into RNAs were distributed in the mother cell and forespore fractions, respectively. The results indicate that more RNA synthesis occurs in the forespores than in the mother cells of sporulating cells.
Abstract. The fine structure and ATPase activity of the mitotic spindle in neoblasts of planaria were examined. In neoblasts, the cells have a large nucleus and nucleolus. Mitochondria are aggregated around the nucleus with chromatoid bodies adjacent. The cytoplasm contains little endoplasmic reticulum (ER) and few Golgi bodies but many free ribosomes, forming polysomes, can be seen throughout the cytoplasmic and spindle ground areas. In addition, centriolar bodies, atypical centrioles, can also be recognized in the cytoplasm. Ceils in the G 2 stage contain a pair of electron-dense bodies, both consisting of fibrogranules but differing from each other in fine structure and, in the mitotic stage, only one fibrogranular body can be recognized at each pole. ATPase activity was detected in the centriolar bodies in the G 2 and mitotic stages and in the ground area of the cytoplasm and spindle apparatus filled by free ribosomes. The activity associated with the microtubules differed with the developmental stage.
ABSTRACT. The distribution of Ca2+ in dividing cells of the maize root tip was examined by potassium pyroantimonate precipitation and EGTA treatment methods. Ca2+ was found in most of the cell organelles, such as the matrix of the mitochondria, the thylakoid membrane of the proplastid and the Golgi vesicles, and on the plasma membrane. Ca2+ was also distributed throughout the cytoplasmic ground matrix and attractoplasm, inside the vacuoles, in the granular zone of the nucleolus in the interphasic nucleus and in the regenerated nucleolus in the telophasic nucleus. The amounts of Ca2+ distributed in the cytoplasmic ground matrix, the vacuole and the nucleolus varied during nuclear division. From the results of the present experiment, the following considerations on the role of Ca2+ and the regulation site of Ca2+ in dividing plant cells were drawn: 1) Ca2+ may play a role in the construction of the granular form of the ribosome. 2) Ca2+ may be an essential ion in the regeneration of nucleolus. 3) Vacuoles may act as the regulatory site of the Ca2+ concentration in the cytoplasm and attractoplasm in plant cells. Spindle microtubules and phragmo-microtubules are probably surrounded by other ions, such as Mg2+.
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