THE EFFECT OF 4-NITROQUINOLINE 1-OXIDE ON THE UPTAKE AND INCORPORATION OF SELECTED AMINO ACIDS BY LACTOBACILLUS CASEI
THE EFFECT OF 4-NITROQUINOLINE 1-OXIDE ON THE UPTAKE AND INCORPORATION OF SELECTED AMINO ACIDS BY LACTOBACILLUS CASEI
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Date
1973-05
Authors
Barker, Charles Lawrence
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Abstract
Utilizing Lactobacilling casei cells an experimental teat
system was developed to measure the effect of varying concentrations
of the potent, water-soluble, oncogen 4-nitroquinoline
1-oxide (4-4Q0) on amino acid uptake and Incorporation by the
bacteria. The rates of uptake, incorporation, and removal of
tritium labeled 4-NQ0 were measured. Clycine-14C, L-alauine-14C,
L-methionine-14C, and L-tyrosine-14C standard uptake and Incorporration
measurements wore also taken.
The labeled aaiino acids all displayed a rapid Initial
uptake with saturation being almost completed after 180 seconds.
The 4-UQ0-3H uptake was initially rapid, reaching a maximum
limit after approximately 60 seconds, after which an equally
rapid renoval of tritium label was experienced. After 180
seconds from the time of oncogen introduction the bacteria had
returned to a bound oncogen label approximately one sixth of the
maximum level.
The standard incorporated amino acid curves showed a
time dependency with maximum levels being reached after 10
minutes. Incorporated oncogen showed an initial level that was
approximately twice as high as the level measured after 180 or
600 seconds.
Of the amino acids tested L-alanine-14C was the most
Sensitive to 4-NQ0 levels. When C.0167 mM 4-NQ0 was introduced
Into the test system reduction of L-alanine-14C uptake was noted.
Incorporation of the same amino acid was stimulated.
In general, the same results were shown for the other
amino acids though they we re less sensitive to the presence of
oncogen. An alteration in the amino acid incorporation curves,
deaonst rating an apparent dependence on the amino acid concentration
in the cell and not on time , was noted in all of the
data.
From the data presented a mechanists for the alteration
of biological systems by 4-nitroquinollne l-oxide was given.
The reasoning suggests that an alteration of the messenger
ribonucleic acid may be the point of initial metabolic change.
Other known oncogens we re also introduced into the
experimental system. They were N-cicrosodimethylamine and
X-nethyl-N'nitro-N'-nitrosoguanidine. Both chemicals induced
a simllar aIteration of the standard L-alanine-14C incorporation
demonstrated by 4-NQ0. These data suggest that this system may
be used to screen potential oncogens.
Description
A Dissertation Submitted to the Faculty of
Baylor University
In Partial Fulfillment of the
Requirements for the Degree
of
Doctor of Philosophy
Keywords
EFFECT OF 4-NITR0QUIN0LINE 1-OXIDE,, UPTAKE AND INCORPORATION,, SELECTED AMINO ACIDS,, LACTOBACILLUS CASEI