Effect of a continuous gamma irradiation at a very low dose on the life span of mice.

Background: There is epidemiological evidence that suggests there are beneficial effects of ionizing radiation at low doses. Some experimental studies confirmed this hormetic effect with doses of about 1 cGy/day, but no data concerning very low dose rates are available.

Objective: The aim of this study was to determine the life span of mice exposed to very low doses of ionizing radiation.

Influence of a long duration exposure, 69 months, to the space flight factors in Artemia cysts, tobacco and rice seeds.

Three french laboratories have participated in the Free Flyer Biostack experiment. Artemia cysts, tobacco seeds and rice caryopsis and embryos were used. Biological objects in monolayers were dead.

[Effects of hypergravity on Paramecium tetraurelia].

Previous space experiments carried out in Paramecium tetraurelia have shown that exposure to microgravity results in an enhancement of cell multiplication. An opposite effect occurs when paramecia are exposed to hypergravity. Changes in cell growth rate observed in hypergravity cannot be ascribed to the bacteria present in the culture medium, the same effect being observed when paramecia grow in sterile medium.

Theoretical and experimental investigations on the fast rotating clinostat.

We have investigated both theoretically and experimentally the validity of the fast rotating clinostat to simulate microgravity for a free swimming single-cell organism such as the paramecium. Computer simulations show that cells on suspension move as cells cultivated in space. However, rotated paramecia are still affected by gravity, as shown by the variations in the rate of paramecium rotation on their axis.

Effects of angular speed in responses of Paramecium tetraurelia to hypergravity.

The paper shows the results of investigations carried out in a single cell organism. Paramecium tetraurelia exposed to different gravitational levels. Hypergravity resulted in a decrease in cell growth rate.