ABSTRACT
In this paper we report an observation of an unusual frequency dependent enhancement of the heat transport parameter (C(p)kappa, C(p) = heat capacity and kappa = thermal conductivity) of a nanofluid containing ZnO nanoparticles of an average size of 10 nm (volume fraction
ABSTRACT
Brief digestion of sarcoma-180 chromatin (less than or equal to 5%) by pancreatic DNase-I releases six non-histone proteins with Mol. wt. 21.5K, 26K, 72.5K, 77K, 90K and 120K dalton and pI values ranging from 4.7 to 12.4. The protein of Mol. wt. 77K dalton was obtained at high alkaline range of pH = 12.4. The antibodies against these proteins induce dose dependent inhibition in transcription of native chromatin. Results suggest a role of these proteins in positive control of gene transcription in sarcoma-180 cells.
Subject(s)
Chromatin/metabolism , DNA-Binding Proteins/isolation & purification , Deoxyribonuclease I/pharmacology , Sarcoma 180/metabolism , Animals , DNA-Binding Proteins/physiology , RNA Polymerase II/physiology , Transcription, GeneticABSTRACT
Binding of nogalamycin and adriamycin with Sarcoma-180 ascites tumor cell chromatin was studied by a spectrofluorometric method. There was significant reduction in the number of available drug binding sites per nucleotide when the chromatin was digested with DNase I for a period which releases only 7% of the chromosomal DNA. Results indicate preferential binding of these drugs with DNase I hypersensitive sites of chromatin. The DNase-I hypersensitive sites of chromatin were shown to correlate to the sequences required for gene expression. Further digestion with DNase I increases availability of drug binding sites, probably due to relaxation of the compact chromatin.
Subject(s)
Chromatin/metabolism , Daunorubicin/analogs & derivatives , Deoxyribonuclease I/metabolism , Doxorubicin/metabolism , Nogalamycin/metabolism , Sarcoma 180/metabolism , Animals , Binding Sites , DNA, Neoplasm/metabolism , Mice , Spectrometry, Fluorescence , ThermodynamicsSubject(s)
DNA/metabolism , Daunorubicin , Doxorubicin , Nogalamycin , Animals , Base Sequence , Cattle , Chemical Phenomena , Chemistry , Chromatin/metabolism , Daunorubicin/analogs & derivatives , Kinetics , Mice , Sarcoma 180 , Structure-Activity Relationship , Thymus GlandABSTRACT
A group of cis-ethylenediammine platinum (II) complexes were synthesized and their activity against Sarcoma-180 ascites tumour cells in mouse was tested. One of the compounds, Pt(HOCH2CH2NHCH2CH2NH2)Cl2, showed significant antitumour activity having little toxicity to the host. Like the parent compound, cis-DDP, it binds to DNA, but transcription is not the primary process inhibited by these compounds. The drug-DNA complex, though less toxic, was not more effective than the free drug.
Subject(s)
Cisplatin/analogs & derivatives , Sarcoma 180/drug therapy , Animals , Chemical Phenomena , Chemistry , Cisplatin/pharmacology , Cisplatin/therapeutic use , DNA, Neoplasm/metabolism , Drug Evaluation, Preclinical , Male , Mice , Sarcoma 180/metabolismABSTRACT
Number of available nogalamycin binding sites in Sarcoma-180 chromatin is less than that present in Sarcoma-180 DNA. Gradual removal of proteins from chromatin by salt leads to increase in available drug binding sites, without appreciable alteration in binding affinity. Histones restrict the accessibility of nogalamycin to chromosomal DNA, whereas high mobility group (HMG) proteins have no effect. Association of histone H1 with chromosomal DNA has a more marked inhibitory effect on nogalamycin binding than other types of histones. Chromosomal protein induced conformational change in DNA appears to be the main factor in determining the availability of strong binding sites.
