The chemical stimulus essential for growth by increase in cell number

Effects of Sulphur Deficiency on Metabolism in Tomato

“…Glutathione also was probably present. The S-H sulphur reactions were largely restricted, however, to the phloem and cambium and to the meristematic tips of stem and roots, a condition that has frequently been observed by others (16,17,19,48). No cystine was observed.…”

“…It may be that in nitrate or sulphate nutrition of tomato, a considerable quantity of the unelaborated ion must be present to furnish the plant at sufficient rate an adequate amount of certain intermediate products of protein synthesis. In this connection it may be pointed out that HAMMETT (17) …”

Further researches on the action of metallic salts on fishes

“…The formation of colloidal precipitate herein described strongly recalls the cases of 'coagulationnecrosis' in foetal placentae induced by Blair-Bell and Annett by the injection of colloidal lead into the pregnant rabbitt (lo), and attributed by them to interaction between the metal and 'some phosphatid, such as lecithin'; Reznikoff (11) has observed a coagulation effect as the result of injecting heavy-metal salts into the cytoplasm of Amoeba ; Lillie(l2) attributes the action of these salts upon Arbacia eggs to a phenomenon of similar origin, and his results suggest that the protection afforded by water in which eggs have been kept for some time may be traceable to the fixation of the metal by colloidal organic extracts; the influence of the salts of heavy metals in retarding respiration in Aspergillus is believed by Cook(l3) to be conditional upon chemical combination between the metallic base and some organic cell constituent; Hammett (17) finds that lead ion induces a retardation of growth by cell division in the roots of seedlings, and attributes this effect to the deactivation (by combination with the metallic ion) of an organic sulfhydryl which he believes to provide the essential stimulus to mitosis; Behrens and Pachur(l4) find lead, when present in the blood, occurring in a colloidal condition at the surface of the erythrocytes, and also in a colloidal and non-dialyzable form in the plasmainstances could be multiplied to show the fundamental simi. larity throughout the apparently diverse effects of heavy metals upon living tissue or organic secretions, and many…”

Biochemistry of the Dividing Cell

“…Thiols.-Thiol groups have demanded attention from students of the biochemistry of cell division since the 1930's (35,111,147). One of the first indications of a major biochemical fluctuation associated with division was Rapkine's (111) finding that "glutathione" (actually TCA-soluble -SH) decreased sharply during the early phases of mitosis in the sea urchin egg and was restored to its original level during the later phases.…”