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Biomedical subjects

S Szala

Publications and source records attributed to S Szala.

At least 37 records · Page 2Linked to original sources
PubMed1982

Complexity of liver mRNA from normal and thioacetamide-treated rats.

The complexity and diversity of polysomal poly(A)-containing RNA (mRNA) isolated from livers of normal and thioacetamide (TAA)-treated rats were compared by mRNA/complementary DNA hybridization technique. Three kinetic components (frequency classes) representing in normal mRNA about: I-34, II-32 and III-34% of RNA, apparently contained about 3, 60 and 3400 different sequences of 1 kb each, respectively. The corresponding values for mRNA from TAA-treated rats were about: I-24, II-36, and III-40%, comprising about 1, 30 and 3200 different sequences. It appeared that abundant mRNA sequences (from components I and II) may be 2-5 times more frequently represented in mRNA from TAA-treated than from normal rats. About 15% of mRNA sequences in TAA-treated rats were apparently transcribed from repetitive DNA reassociated to a Cot of 100. The results suggested that thioacetamide, a potent hepatocarcinogen, modulates the transcription or post-transcription regulatory steps of a few selected mRNA species, leading to their accumulation in the cell.

Acetamides↗
PubMed1977

Transcription of rat DNA fractions reassociated to various cOt values.

Two fractions of rat liver DNA: "intermediate" (reassociated to COt = 1 - 10(2), moleXsecX1(-1)) and "slow" (COt = 10(2) - 10(5) showed differences in template activity on transcription with E. coli RNA-polymerase. The "intermediate" fraction both in double- and single-stranded form was a better template than the "slow" one. The efficiency of transcription dropped progressively for the template obtained at COt values increasing from 10(2) to 10(6). No differences in the template activity of the "intermediate" and "slow" fractions were observed when rifampicin-resistant transcription was studied.

Animals↗
PubMed1976

Interspersion and transcription of repeated sequences of rat DNA.

Repetitive rat DNA reassociated to Cot=0.1 and deprived of "foldback" sequences showed close interspersion with unique sequences. As measured by electron microscopy, the average length of repetitive segments was about 600 +/- 400, and of unique segments 1800-3600 base pairs. Pyrimidine tracts over 80 nucleotides in length were found mainly in foldback and repetitive fractions. Oligo(dT) tracts, 20-30 bases in length prevailed in the DNA fraction reassociated to Cot=0.1. Repetitive and unique DNA fractions were annealed to Millipore filters and hybridized with hnRNA. Up to 1.6% of repetitive DNA reassociated to Cot=0.05 showed base complementarity with hnRNA, whereas the comparative figures for DNA reassociated to Cot=10 and for the unique fraction were 0.8% and 0.3% respectively. When hybridization of hnRNA was carried out in solution in vast DNA excess, no hybrid formation with repetitive sequences reassociated to Cot=0.1 was observed, although hybridization with DNA reassociated to Cot=10 was noticeable.

Base Sequence↗