Cobalt, Copper and Molybdenum in the Nutrition of Animals and Plants

Abstract

During the past 25 years Co, Cu, and Mo have been proven to be essential nutrient elements; physiological processes are now known to be served in animals by Co and Cu, and in plants by Cu and Mo. There is, however, no acceptable evidence of an essential role for Mo in animals, nor for Co in the higher plants. In so far as is known at this juncture, Co serves no useful purpose in the animal other than as an integral part of the accessory food factor, vit. B12, which originates in nature only as a metabolic product of certain micro-organisms, and is absent from the higher plants upon which the animal depends ultimately for sustenance. The direct dependence of animals on micro-organisms for an essential foodstuff creates a nutritional situation which is unique in our knowledge and suggests a persistent consequence of an early symbiotic relationship that has not been lost in the course of evolution. Cu is probably an essential nutrient element for all plants and animals and, more than likely, serves a physiol. process common to all living cells, but a universal function in living matter that may be ascribed to Cu has proved elusive, although many specialized functions are known to depend on Cu-containing oxidases. Mo is known to serve in metabolic processes concerned with the utilization of N in plants and apparently has no physiological function in the animal organism. The author gives for each of these elements its relation to plant nutrition; and, in the animal body, its mode of absorption and excretion, the effect of a deficiency, and the effect of an excess. Vit. B12 is discussed in relation to its chemistry and degradation products, absorption, excretion, human megaloblastic anemias, microbiological origin, animal protein factor, methylations in vivo, induced hyperthyroidism, protein metabolism, and nucleic acid synthesis. Other topics touched upon are Co and polycythemia; influence of Mo on Cu metabolism; and the connection of Cu with demyelinating disease in sheep, with Fe metabolism, with melanin, respiratory and turacin pigments, with keratinization, with Cu enzymes and quinone tanning of structures in invertebrates. 828 references.