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P HARRIS

Publications and source records attributed to P HARRIS.

At least 37 records · Page 2Linked to original sources
PubMed1961

The direct isolation of the mitotic apparatus.

A method for isolating the mitotic apparatus from dividing sea urchin eggs without the use of ethyl alcohol or of detergents is described. In the present method, the eggs are dispersed directly in a medium containing 1 M (to 1.15 M) sucrose, 0.15 M dithiodiglycol, and 0.001 M Versene at pH 6, releasing the visibly intact mitotic apparatus. The method is designed for studies of enzyme activities, lipid components, and the variables affecting the stability of the apparatus.

Animals↗
PubMed1961

Electron microscope study of mitosis in sea urchin blastomeres.

The fine structure of cells at different stages of the mitotic cycle was studied in the blastomeres of 6-hour-old embryos of the sea urchin Strongylocentrotus purpuratus. The material was fixed in 1 per cent osmium tetroxide in sea water, buffered with veronal-acetate to pH 7.5, embedded in Araldite, and sectioned with glass knives. The aster, as it forms around the centriole, has the appearance of the endoplastic reticulum, with elements oriented radially from the centrosphere to the periphery of the cell. Anaphase structures described include the kinetochores, with bundles of fine filaments extending toward the centrioles, as well as continuous filaments passing between the chromosomes. Two cylindrical centrioles composed of parallel rods are present in each of the anaphase asters. At late anaphase, elements of the endoplasmic reticulum condense on the surface of the chromosomes to form a double membrane which already at this stage possesses pores or annuli. At telophase bundles of continuous filaments can be seen in the interzonal region. These filaments, as well as those associated with the chromosomes, have a diameter of approximately 15 mmicro, and appear physically different from the astral structure.

Anaphase↗