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G M Cook

Publications and source records attributed to G M Cook.

69 records · Page 4Linked to original sources
PubMed1976

Isolation of a Golgi-apparatus-enriched fraction from leukaemic cells.

1. A Golgi-apparatus-enriched fraction was isolated from acute leukaemic lymphoblasts of AKR mice by using an homogenate stabilized with 1 mM-glutaraldehyde. 2. The isolated fraction, which was shown morphologically to be enriched in dictyosomes, possessed between 44- and 76-fold increase in specific activity, compared with the tumour homogenate, of UDP-galactose-glycoprotein galactosyltransferase and between 3- and10.5-fold increase in relative specific activity of UDP-N-acetygalactosamine-polypeptide N-acetylgalactosaminyltransferase. 3. Plasma membranes isolated from the leukaemic lymphoblasts also possessed glycoprotein galactosyltransferase activity, though in contrast with Golgi-apparatus-enriched material had no detectable polypeptide N-acetygalactosaminyltransferase. 4. The difficulties associated with maintaining the morphological integrity of the Golgi apparatus in subcellular fractionation are discussed.

Animals↗
PubMed1976

Comparison of early embryonic and differentiating cell surfaces. Interaction of lectins with plasma membrane components.

1. Cells of the unincubated as well as those of primitive streak chick blastoderm, which are preparing for or are involved in morphogenetic movements, are agglutinated by wheat germ agglutinin, Ricinus communis agglutinin and concanavalin A, but not by fucose-binding protein. 2. Agglutination of these cells with soybean agglutinin occurs only after neuraminidase treatment, while that induced by concanavalin A, wheat germ and Ricinus communis agglutinins is not affected. 3. Trypsin treatment of blastoderm cells had no effect on lectin-mediated agglutination. 4. In contrast, cells derived from 10-and 12-day differentiating chick liver were agglutinated by wheat germ agglutinin only after trypsinization. 5. Mechanically dissociated embryonic liver cells, which are not agglutinated, bind more 3H-labelled wheat germ agglutinin per cell than trypsinized cells, suggesting that during differentiation there may be a spatial reorganization of wheat germ agglutinin receptors within the plasma membrane. 6. Membranes isolated from the above cell types were examined by analytical polyacrylamide gel isoelectric focusing and, in combination with affinity chromatography using wheat germ agglutinin conjugated to agarose, membrane material in the differentiating liver membrane, which binds to this lectin, was identified.

Acetylgalactosamine↗
PubMed1968

The electrophoretic mobility of normal and leukaemic cells of mice.

1. The pH-mobility relationships for saline-washed cells from a mouse strain of acute lymphoblastic leukaemia were examined before and after treatment with lower aldehydes, diazomethane and neuraminidase (EC 3.2.1.18). 2. The content of sialic acid released into the supernatant fluid of neuraminidase-treated cells was measured. 3. The stability of the charge-determining structures to temporary changes in environment (pH and ionic strength) was established. 4. Similar measurements were made on lymph-node cells obtained from non-leukaemic mice (a resistant and a leukaemia-susceptible strain were examined). 5. It is deduced that both the malignant and the non-malignant cell possess two dissociable acid functions at the cell surface, a carboxyl group of sialic acid and another acidic group(s), probably carboxyl, of pK 3.0-4.5. The malignant cells, however, have a basic dissociable function not present in the non-malignant types. 6. Suggestions are made as to how the difference in surface chemistry may be related to the problem of malignancy.

Aldehydes↗