L.D.H. and L.D.H. isoenzymes of the intra-uterine secretions of the cow during the estrous cycle

Uterine secretions were collected from 20 mature cows during estrus (day 0), metestrus (day 5), diestrus (day 10) and proestrus (day-1). Lactate dehydrogenase (LDH) and LDH isoenzymes activity were evaluated. No significant cyclic variations of LDH activity was found in the uterine secretions while the mean of the enzyme activity was higher during the estrogenic period of the cycle. The relative activity of LDH-1, LDH-2 and LDH-3 isoenzymes were higher during proestrus and estrus whereas LDH-5 activity was more important during metestrus. The LDH-3 seems to have the higher relative activity in uterine secretions of the cow.     

J. B. S. Haldane and the origin of life

In 1929 the British biologist John Burdon Sanderson Haldane published a hypothesis on the origin of life on earth, which was one of the most emblematic of the interwar period. It was a scenario describing the progressive evolution of matter on the primitive earth and the emergence of life. Firstly, this paper presents the main ideas put forward by Haldane in this famous text. The second part makes comparisons between Haldane and Alexander Ivanovitch Oparin’s ideas regarding the origins of life (1924). These two theories, apparently very similar, presented distinct conclusions. The third part focusses on Haldane’s reflections on the emergence of life during the 1950s and 1960s, and shows how they were linked to the recent developments of prebiotic chemistry and molecular biology.