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Biomedical subjects

J F Danielli

Publications and source records attributed to J F Danielli.

At least 19 recordsLinked to original sources
PubMed1978

Characteristics of the 'life spanning' phenomenon in Amoeba proteus. Independent nuclear and cytoplasmic ability to impose finite 'life span'.

Amoeba proteus given adequate food grows exponentially and clones of amoebae are normally immortal. After periods of food supply restriction to that necessary for maintenance, or food intake restriction by agitation, cells subsequently given a normal growth diet produce clones of finite life span. Reciprocal nuclear transfer between maintained and normal cells demonstrated that the nucleus and cytoplasm of maintained cells have acquired the independent ability to impose a finite life span on clones developing from cells whose other components are normal. In clones developing from maintained cells, inviable cell production is enhanced and inter-division times are prolonged. Inter-division times and clones mean doubling times do not show normal distribution.

Amoeba↗
PubMed1974

Chemical characterization of the isolated cell surface of Amoeba.

The cell surface has been isolated from uninucleate, freshwater, phagocytic amoebae by a new procedure. Several criteria were employed to demonstrate purity of the cell surface fraction. All morphological components of the tripartite surface were present in the isolated surface and the weight of the isolated surface was quantitatively accounted for by the components analyzed. Chemical analyses showed the presence of lipid, protein, and carbohydrate. Mannose was the predominant neutral sugar. Analyses for three different strains of Amoeba were similar. Phosphate was found to be the major anionic group in the cell surface material. Sulfate, uronic acid, sialic acid, muramic acid, and nonamidated glutamic acid and aspartic acid were absent. Evidence is presented suggesting that the phosphate is associated with an unidentified nonreducing polyol.

Acid Phosphatase↗
PubMed1970

Reassembly of living cells from dissociated components.

Combining the techniques of nuclear transplantation and cytoplasmic transfer, dissociated amoeba nuclei, cytoplasm, and membranes were reassembled to form viable amoebae. The techniques of cell reassembly appear to be sufficiently adequate so that any desired combination of cytoplasm, nucleus, and membrane can be assembled into living cells.

Amoeba↗