The question of how the presence of nucleosomal
packing of DNA modifies carcinogen interaction at
specific sites cannot be answered by studies on whole
chromatin or bulk nucleosomes because of the
heterogeneity of DNA sequences in the particles. This
problem was circumvented by constructing nucleosomes that
are homogenous in DNA-histone...
The rainbow trout (Oncorhynchus mykiss) model
of chemical carcinogenesis is becoming increasingly
important as a supplement to rodent studies. However,
much of the molecular biology of the carcinogenic
response is still unknown in the trout model. The ras
gene family has been implicated in the tumorigenesis of
both spontaneous and...
For ras gene mutation analysis in the rainbow trout (Oncorhynchus
mykiss) model system, a partial trout ras sequence was identified
using the polymerase chain reaction (PCR). Two synthetic
oligonucleotides based on rat K-ras gene sequence were used as
primers for the PCR procedure. A 90 base pair (bp) sequence,
referred...
Chlorophyllin (CHL), a water-soluble derivative of the green plant pigment, chlorophyll, is an effective antimutagen and anticarcinogen in various model systems when used as a modulator against a class of carcinogens that, in general, have a structure consisting of at least three fused rings. Dibenzo[a,l]pyrene (DBP), an extremely potent environmental...
Dimethylbenz (a) anthracene (EMBA), a carcinogen that requires
metabolic activation to produce active metabolites capable of
binding to DNA, has been studied in the trout and other fish.
Polycyclic aromatic hydrocarbons (PAH) are of importance as they
are ubiquitous in the environment and their carcinogenic effects
in fish from contaminated...
Indole-3-carbinol (I3C) inhibits chemically induced tumor
formation in rodents and rainbow trout. This study examines the
effect of I3C and its analog, indole-3-acetonitrile (I3N) on
xenobiotic-metabolizing enzyme systems. The modulation of these enzyme
systems have been shown to have significant effects on the
interaction of chemical carcinogens and cellular constituents....
A digoxigenin-labeled nonradioactive detection system was used
to screen a zebrafish cDNA library for p53-like and ras-like genes.
One clone was isolated and identified as an incomplete p53-like
gene. The insert size of this clone is 1777 bp, which encodes part of
evolutionarily conserved region II and all of regions...
In rodent models as well as in fish models there are significant
species differences in the susceptibility toward aflatoxin B₁ (AFB₁)
carcinogenesis. Mouse is less susceptible toward AFB₁ carcinogenesis
than rat. Researchers have come to the conclusion that the lower
susceptibility of mice is not a result of less effective...