The University of Southampton
University of Southampton Institutional Repository

Relative sensitivities of nuclei and cytoplasm of Amoeba proteus to chemical carcinogens and mutagens

Relative sensitivities of nuclei and cytoplasm of Amoeba proteus to chemical carcinogens and mutagens
Relative sensitivities of nuclei and cytoplasm of Amoeba proteus to chemical carcinogens and mutagens

The Amoeba Proteus single cell model has been used as a system for toxicological investigations of six chemical carcinogens and mutagens - N-methyl-N-nitrosourea, dimethyl sulphate, methylmethane sulphonate, hydroxylamine, hydrazine and 2(achloroppropylamino) ethyl napthylene hydrochloride.One of the unique features of this system is the high toleranceof cells to nuclear transfer. This enables observations indicating the cell nucleus or cytoplasm as the main site of action of toxic chemicals. Parameters considered have included cell survival, delays to mitotic cell division and abnormal divisions and cell growth.The toxic effects of N-methyl-N-nitrosourea, a potent carcinogen, were shown to be predominantly directed at the cell nucleus. Cells in the DNA synthetic phase of the cell cycle were most sensitive and long mitotic division delays during which abnormal growth occurred were observed.2(achloropisopropylamino) ethyl napthylene hydrochloride, a carcinogen, was similarly toxic through its action on the cell nucleus when cells were exposed in the presence of mammalian liver enzyme fractions. In the absence of the enzyme preparation this chemical was toxic through its action on the cell cytoplasm.Division delays were significant but sot as great as with N-methylN-nitrosourea.Dimethyl sulphate and methylmethane sulphonate, both carcinogens, were toxic to both the cell nucleus and cytoplasm. The results also demonstrate that treated cells with damaged nuclei in a viable cell cytoplasm could be envisaged.The toxicity of hydrazine and hydroxylamine, carcinogenic and non-carcinogenic respectively, was directed to the cell cytoplasm. The only effects on nuclei were observed as slight delays to mitotic cell division and in the case of hydrazine abnormal growth and division. It is more difficult, from these results, to envisage cells with damaged nuclei in viable cytoplasms arising. The results demonstrate some chemical properties that may be related to carcinogenicity. The concept that arises involves persistent nuclear lesions in viable cells as the basis for carcinogenic transformation, at least for chemicals which are carcinogenic through their DNA damaging ability.

University of Southampton
Chatburn, Graham Richard
f8c9ec9a-fcda-485b-9b62-a06b4607bcb5
Chatburn, Graham Richard
f8c9ec9a-fcda-485b-9b62-a06b4607bcb5

Chatburn, Graham Richard (1977) Relative sensitivities of nuclei and cytoplasm of Amoeba proteus to chemical carcinogens and mutagens. University of Southampton, Doctoral Thesis.

Record type: Thesis (Doctoral)

Abstract

The Amoeba Proteus single cell model has been used as a system for toxicological investigations of six chemical carcinogens and mutagens - N-methyl-N-nitrosourea, dimethyl sulphate, methylmethane sulphonate, hydroxylamine, hydrazine and 2(achloroppropylamino) ethyl napthylene hydrochloride.One of the unique features of this system is the high toleranceof cells to nuclear transfer. This enables observations indicating the cell nucleus or cytoplasm as the main site of action of toxic chemicals. Parameters considered have included cell survival, delays to mitotic cell division and abnormal divisions and cell growth.The toxic effects of N-methyl-N-nitrosourea, a potent carcinogen, were shown to be predominantly directed at the cell nucleus. Cells in the DNA synthetic phase of the cell cycle were most sensitive and long mitotic division delays during which abnormal growth occurred were observed.2(achloropisopropylamino) ethyl napthylene hydrochloride, a carcinogen, was similarly toxic through its action on the cell nucleus when cells were exposed in the presence of mammalian liver enzyme fractions. In the absence of the enzyme preparation this chemical was toxic through its action on the cell cytoplasm.Division delays were significant but sot as great as with N-methylN-nitrosourea.Dimethyl sulphate and methylmethane sulphonate, both carcinogens, were toxic to both the cell nucleus and cytoplasm. The results also demonstrate that treated cells with damaged nuclei in a viable cell cytoplasm could be envisaged.The toxicity of hydrazine and hydroxylamine, carcinogenic and non-carcinogenic respectively, was directed to the cell cytoplasm. The only effects on nuclei were observed as slight delays to mitotic cell division and in the case of hydrazine abnormal growth and division. It is more difficult, from these results, to envisage cells with damaged nuclei in viable cytoplasms arising. The results demonstrate some chemical properties that may be related to carcinogenicity. The concept that arises involves persistent nuclear lesions in viable cells as the basis for carcinogenic transformation, at least for chemicals which are carcinogenic through their DNA damaging ability.

This record has no associated files available for download.

More information

Published date: 1977

Identifiers

Local EPrints ID: 462727
URI: http://eprints.soton.ac.uk/id/eprint/462727
PURE UUID: 3fe4bc17-78cc-40e0-941f-e8199eb83226

Catalogue record

Date deposited: 04 Jul 2022 19:46
Last modified: 23 Jul 2022 01:08

Export record

Contributors

Author: Graham Richard Chatburn

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×