Treatment of cultured mouse fibroblasts (L-cells) and hamster kidney cells with ethidium bromide was found to inhibit the incorporation of [(3)H]thymidine into mitochondrial closed-circular DNA, but not into nuclear DNA. The specific activity of nuclear DNA in treated cells was higher than in control cells. Treatment also led to breakdown of closed-circular mitochondrial DNA, greatly enlarged m...

A cytogenetic study was carried out on the chromosomes and the nuclear DNA content of the freshwater goby Economidichthys pygmaeus (Pisces, Gobiidae). The species is characterized by a 2n=46 karyotype consisting of 12 submetacentric and 11 subtelocentric chromosome pairs (NF=70). Major (45S) rDNA genes are terminal-centromeric located on the short arm of a single medium-small sized submetacentr...

The deoxyribonucleic acid (DNA) content of Feulgen-stained interphase nuclei from human amnion epithelium and liver parenchyma as well as the DNA content of their sex chromatin or heterochromatic bodies was determined histophotometrically. In female nuclei the ratio between the nuclear DNA content and that of their sex chromatin or heterochromatic bodies remains constant irrespective of the pol...

In growing plasmodia of the myxomycete Physarum polycephalum (G2-phase), three distinct classes of nuclei with a relative DNA content of 1x, 2x, and 4x are observed in the presumed haploid strain CL. The 2x and 4x species comprise up to 35% and 5% of the nuclei. Quantitative cytofluorometric studies of nuclei isolated in either G2- or S-phase or after FUDR treatment (G1 arrest) show that the th...

Nuclear preparations of the Walker 256 carcinosarcoma, Novikoff hepatoma, Morris hepatoma 7794, and Morris hepatoma 9108 were successively extracted with 0.15 M and 2 ~ NaC1 solutions to obtain the "nuclear sap" and "DNA" or chromatin fractions, respectively; the residue fraction contains much of the nucleolar RNA as well as other RNA of the nuclear ribonucleoprotein network (24). The RNA prepa...

Nuclear DNA content in gametophytes and sporophytes or the prostrate phases of the following species of Bonnemaisoniaceae (Asparagopsis armata, Asparagopsis taxiformis, Bonnemaisonia asparagoides, Bonnemaisonia clavata and Bonnemaisonia hamifera) were estimated by image analysis and static microspectrophotometry using the DNA-localizing fluorochrome DAPI (4', 6-diamidino-2-phenylindole, dilacta...

Nuclear preparations of the Walker 256 carcinosarcoma, Novikoff hepatoma, Morris hepatoma 7794, and Morris hepatoma 9108 were successively extracted with 0.15 M and 2 ~ NaC1 solutions to obtain the "nuclear sap" and "DNA" or chromatin fractions, respectively; the residue fraction contains much of the nucleolar RNA as well as other RNA of the nuclear ribonucleoprotein network (24). The RNA prepa...

The carcinogenic process in the liver was monitored from early nonneoplastic changes to the development of tumors in two well-known models; IP administration of dimethylnitrosamine (DMN) to newborn mice, and feeding of rats with acetylaminofluorene (AAF). Liver parenchyma cells and liver tumor cells were isolated by collagenase treatment and prepared for flow cytometric (FCM) measurements of nu...