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Biomedical subjects

L Cocco

Publications and source records attributed to L Cocco.

At least 145 records · Page 8Linked to original sources

H2B nucleohistone-phospholipid interactions. Thermal denaturation and ultrastructural analysis.

Sphingomyelin, phosphatidylserine, bovine lecithin and phosphatidylethanolamine modify the thermal stabilization of H2B-DNA complexes, by inducing stabilization at 0.3 and 0.6 H2B : DNA weight ratios and destabilify the arrangement of nucleohistone is confirmed by ultrastructural analysis which indicates a competitive action of these molecules during the nucleoprotein assembly. A possible regulatory role of phospholipids on native chromatin is proposed.

Chromatin↗

Chromatin phospholipids in normal and chronic lymphocytic leukemia lymphocytes.

Certain phospholipids are associated with the nonhistone chromosomal proteins extracted from normal B- and chronic lymphocytic leukemia lymphocytes. The ratio of phospholipids to nonhistone chromosomal proteins was constant with the different methods used for isolating nuclei and extracting the chromatin, although the various methods allowed a different recovery of total lipids from chromatin. Three phospholipids were extractable from the nonhistone protein fraction, but their respective ratios varied in chronic lymphocytic leukemia compared to normal B-lymphocytes. The most significant variation concerns the reduction of sphingomyelin content in leukemic lymphocytes, since this prospholipid in vitro affects both DNA stability and transcription.

B-Lymphocytes↗

Phospholipids bound to acidic nuclear proteins in human B and T lymphocytes.

Chromatin fractions (DNA, histones and non-histone chromosomal proteins NHCP) have been isolated from human peripheral B and T lymphocytes using different methods and analyzed in order to identify their lipid content. While DNA and histone fractions do not reveal the presence of lipids, a 2% of phospholipids is present in the NHCP fraction. The phospholipids associated with NHCP present a constant relative ratio among sphingomyelin, phosphatidyl-choline and phosphatidyl-ethanolamine both in B and T lymphocytes, whichever are the extraction procedures employed. These findings are related to the possible dereprssive role of phospholipids on DNA-dependent RNA synthesis.

B-Lymphocytes↗

Chromosomal proteins in human B and T lymphocytes.

Histones and non-histone chromosomal proteins were characterized in B and T human lymphocytes by means of polyacrylamide disc gel electrophoresis. It was found that while histones do not present appreciable differences in the two examined populations, non-histone chromosomal proteins exhibit distinct electrophoretic profiles. Low molecular weight proteins predominate in B lymphocytes whereas high and intermediate proteins are largely represented in T lymphocytes. The latter proteins may be related to the capability of these resting cells to proliferate under appropriate antigenic stimuli.

B-Lymphocytes↗