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R E KANE

Publications and source records attributed to R E KANE.

7 recordsLinked to original sources
PubMed1965

THE MITOTIC APPARATUS. PHYSICAL-CHEMICAL FACTORS CONTROLLING STABILITY.

Previous investigations have shown that the mitotic apparatus (MA) can be isolated from dividing sea urchin eggs in water buffered at pH 5.6 and that the addition of 1 M hexanediol to the solution raises the usable pH to 6.4. Long chain glycols appeared to be much more effective than related compounds in increasing the stability of the MA, and the aim of the investigations reported here was to determine the basis of this specificity. These experiments show that this impression of specificity is misleading and that under suitable experimental conditions a variety of compounds can be substituted for the glycols. A number of alcohols will duplicate the action of the glycols in stabilizing the MA at pH 6.4, but they must be used at a similar per cent concentration rather than at a similar molar concentration. Increases in the concentration of alcohol or glycol allow isolation at more alkaline pH values, and a pH-concentration relation for the stability of the MA, covering the range from pH 5.6-8, has been determined. These results indicate that the action of these compounds in stabilizing the mitotic apparatus is non-specific and is similar to their effects on the solubility of proteins. The isolation and stabilization of the mitotic apparatus can thus be viewed as a function of the solubility properties of its constituent proteins, opening a variety of new experimental approaches to this problem.

Animals↗
PubMed1962

The mitotic apparatus: isolation by controlled pH.

The isolation of the mitotic apparatus (MA) from the echinoderm egg was studied in detail, with particular attention given to the factors governing its stability. Successful isolation depends mainly on the pH of the isolation solution, slightly acid values being required. The use of a 1 M solution of hexanediol, buffered at pH 6.0 to 6.4, gives high yields of stable MA, while MA of poorer quality can be isolated in water buffered at pH 5.5 to 5.8. Isolation is possible only over a very narrow range of pH, as the cells become more difficult to break at lower values and the MA becomes unstable at higher values. Within this range the fibrous structure of the MA varies with the pH. The isolated MA disintegrates slowly when transferred to water at pH 7 and dissolves rapidly in solutions of high ionic strength.

Animals↗
PubMed1962

The mitotic apparatus. Fine structure of the isolated unit.

The fine structure of the mitotic apparatus isolated from the sea urchin egg has been investigated. The isolation was accomplished by lysis of metaphase eggs in a 1 M solution of hexanediol, buffered at pH 6. The fine structure of the isolated apparatus was studied after fixation with osmium tetroxide directly in the isolation medium. The spindle is composed of fine fibrils, approximately 20 mmicro in diameter, which appear tubular. Similar fibrils, radially oriented, are found in the aster. If the isolated mitotic apparatus is exposed to water at pH 6 before fixation, the structure is considerably modified. The most pronounced effects are an increase in the number of large membrane-bounded vesicles and in the amount of free granular material present. The conditions necessary for the fixation of the mitotic apparatus in dividing cells are discussed in the light of these observations on the isolated unit.

Animals↗
PubMed1960

The effect of partial protein extraction on the structure of the eggs of the sea urchin, Arbacia punctulata.

The structure of the eggs of the sea urchin, Arbacia punctulata, has been investigated after the removal of one-half of the cellular protein. The procedure involves treatment of the eggs with 30 per cent ethanol at -10 degrees C. followed by extraction of the soluble proteins with water. The eggs remain intact, although all of the cytoplasmic matrix is removed. Most cell structures can still be identified, although only the membranes of most remain. The mitochondria lose all of their matrix but retain the inner membranes or cristae. The annulate lamellae appear unaffected by this extraction procedure, remaining intact and apparently undamaged. The nuclear envelope is also retained, although it often undergoes a curious disorganization, apparently as the result of the separation of its two layers. The significance of these observations with respect to the structure of the envelope is discussed.

Animals↗