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Biomedical subjects

F A Manzoli

Publications and source records attributed to F A Manzoli.

At least 109 records · Page 6Linked to original sources
PubMed1981

Interactions among DNA, metallic ions, and lipids.

Interactions amond DNA, phospholipids, and Cu2+ ions have been investigated by means of thermal denaturation technique. The results indicate that phosphatidylserine and sphingomyelin interact with Cu2+ ions, which are able to prevent the chance of binding of the phospholipids to the double helix. This interaction is strictly dependent upon the concentration of the divalent cation and reduces the capability of the employed phospholipids to modify the thermal stability of DNA.

Chemical Phenomena↗
PubMed1979

Effect of phosphatidylcholine vesicles on the activity of DNA polymerase-alpha.

Phosphatidylcholine vesicles stimulate the activity of the DNA polymerase-alpha from calf thymus. This effect is dependent upon the way of addition to the Mg ions, and the extent of the 3H-dTTP incorporation is closely related to the concentration of the vesicles. A role of phospholipids on the activity of the DNA-related enzymes is suggested.

Animals↗
PubMed1978

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↗
PubMed1978

Enzymes involved in adenine nucleotide metabolism of developing chick embryo liver.

1. This paper describes the changes in the activity of adenylate deaminase, adenylate and inosinate phosphatase, and adenosine deaminase in the developing chick embryo liver. 2. The adenylate and inosinate phosphatase and adenosine deaminase activity appears considerably higher in chick embryo liver with respect to other chick embryo tissues previously examined. 3. During development the control exerted by ATP on AMP breakdown undergoes variations. Consequently, in the first period of incubation AMP is degraded by the direct pathway (AMP-IMP) and in the last period of incubation by the indirect pathway (AMP-adenosine). In the intermediate period (from the 12th to the 15th day of incubation) both pathways may be followed. 4. The ability to synthesize purine nucleotides through "salvage pathway" seems to be acquired by embryonic liver at least at the 15th day.

5'-Nucleotidase↗
PubMed1977

Cytophotometric characterization of cortical and medullary lymphocytes in the chicken bursa and thymus.

We have evaluated by means of cytophotometric techniques the nuclear content in DNA, in total nucleic acids and in histone proteins and the nuclear volume of the thymic and bursal lymphocytes in adult chickens. We have also made the same determinations in the developing bursal follicles before and after hatching. The results indicate that cortical differ from medullary lymphocytes for all the parameters considered both in thymic lobules and bursal follicles. Furthermore these differences appear analogous in both the organs, independently from the fact that they produce precursors of T and B lymphocytes respectively. As concerns the developing bursal follicle, the lymphocytes show the characteristics of the adult medullary lymphocytes. At the hatching changes occur in the nuclear content of total nucleic acids and histones. This is probably related to the exposure to antigenic stimulation through the cloaca.

Animals↗
PubMed1977

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↗
PubMed1976

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↗
PubMed1976

Lipid-F1 nucleohistone interactions.

High concentrations of phospholipids determine destabilization of F1 histone-DNA complex at the weight ratios, histone:DNA, 0.8:1 and 1:1, but low concentrations cause only negligible destabilization. Cholesterol at high weight ratios has little effect on nucleohistone stability. Only linolenic acid of the fatty acids used reproduces similar changes in the thermal stability of F1 histone-DNA complex as phospholipids. The type of interaction of phospholipids with the F1 histone-DNA complex is analyzed, and the involvement of phospholipids in DNA replication in vivo is discussed.

Binding Sites↗
PubMed1976

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↗