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Biomedical subjects

J C Mestre

Publications and source records attributed to J C Mestre.

9 recordsLinked to original sources
PubMed1987

A flow cytometric study of DNA staining in situ in exponentially growing and stationary Euglena gracilis.

DNA stainability by different fluorochromes has been compared in exponentially dividing and stationary Euglena cells. With the intercalating fluorochromes, ethidium bromide, acridine orange and DAPI, a decrease of fluorescence intensity of the G1 cells is observed when cells enter stationary stage. However this decrease of fluorescence is not obtained with the nonintercalating fluorochrome Hoechst 33258. If nuclear basic proteins are extracted, however, the intensity of staining by either Hoechst 33258 or ethidium-bromide is comparable in stationary and dividing cells. Therefore, the decrease of fluorescence intensity of the G1 cells observed during the transition from exponential to stationary phase is not due to a loss of DNA but is related to the exposure of chromatin binding sites for ethidium bromide. In Euglena cells, DNA accessibility for intercalating fluorochromes depends upon chromatin structure and consequently upon cell age.

Acridine Orange↗
PubMed1986

Cadmium-induced ultrastructural changes in Euglena cells.

The ultrastructure of Euglena gracilis grown in the presence of Cd showed only numerous myelin-like structures in mitochondria, chloroplasts altered in shape, and thylakoid arrangement and increase of osmiophilic plastoglobuli. These alterations indicate that respiratory processes are the initial target of Cd toxicity.

Animals↗
PubMed1981

Flow fluorometric study of DNA content in nonproliferative Euglena gracilis cells and during proliferation.

Ethanol-fixed Euglena gracilis cells have been analyzed by flow microfluorometry during the lag, logarithmic and stationary phases. The histogram of a plateau stage culture reveals, as expected, an unimodal distribution, but the peak is at lower fluorescence intensity as compared to G1 logarithmic cells. The fluorescence intensity drops as the cells enter the stationary stage. Ultimately the decrease represents a change of about 25%. When cells recover from the plateau stage, the fluorescence intensity increases during the lag phase, and climbs to the level found in a G1 logarithmic population. The reason for the decrease in the fluorescence intensity during the stationary stage may be due to a possible loss of DNA or to a decrease in the number of chromatin-binding sites for intercalating ethidium bromide.

DNA↗
PubMed1977

[The effect of 3 mercury derivatives on the growth of Euglena gracilis Z].

The study of the toxicity of three mercuric derivatives on the growth of Euglena gracilis Z. shows that these chemicals act according to two different ways: quick inhibition of the growth for a peculiar concentration or progressive inhibition characterized by a lag-phase, the significance of which is discussed.

Animals↗