Biosynthesis and metabolism of 1,4-diaminobutane, spermidine, spermine, and related amines.

The polyamines in the central nervous system.

Publisher Summary This chapter investigates the links between polyamines and tumors. It is particularly interesting to modify the culture conditions to clarify the influence of the environmental milieu on the activities of the polyamine biosynthetic enzymes by enhancing or decreasing the levels of these enzymes to see the role of polyamines in the cell growth process. To this purpose, several studies have been carried out with rat hepatoma cells growing in culture. Studies of the effects of growth conditions on ornithine decarboxylase (ODC) activity presents evidence that dilution of high-density hepatoma cell cultures with fresh medium results in a very large and transient increase in enzyme activity. Furthermore, among the factors affecting the growth conditions of the cultured cells, the addition of fresh medium or serum to the culture has been demonstrated to be one of the most important for a variety of other cell lines. In spite of the decades of research, most of the role of polyamines in eliciting the peculiar neoplastic behavior and in permitting invasive neoplastic growth remains unclear.

Polyamines in mammalian tumors. Part I.

Ornithine decarboxylase as a tool in developmental neurobiology

Publisher Summary The chapter discusses that meat has occupied a unique position in the human diet since man's primitive beginning. Today it is still regarded as an important ingredient of any menu. From the deep surface of the epimysium, septa pass frequently into the muscles at irregular intervals. These septa, which constitute the perimysium, invest the primary bundles (fasciculi) of muscle fibers. Muscle cells contain a large variety of proteins with many of them involved in the glycolytic pathway of muscle metabolism and the contraction-relaxation process. The fibers of striated muscle are elongated and more or less tubular, and vary in size and shape. The subject of meat quality has become increasingly scientific with less reliance now being placed on personal judgment and more on physical and chemical tests. According to Kramer and Twigg, the quality of a food may be defined as the composite of those characteristics that differentiate individual units of a product and have significance in determining the degree of acceptability of those characteristics by the consumer. Meat production is fundamentally based on the growth process from the time of fertilization of the ovum until the animal has reached the final age and stage of development determined by its genetic potential. This chapter discusses that the physical, chemical, and histological properties of muscle change markedly during the first 24 hours following slaughter. Complete bleeding is very important as blood provides an ideal medium for the multiplication of bacteria and facilitates their distribution throughout the carcass.

Influence of Ante- and Postmortem Treatments Upon Muscle Composition and Meat Quality

— Spermine and spermidine reach maximum concentrations in the chick embryo brain between the 12th and 14th day of incubation. Sucrose-density-gradient analysis of polyribosome distribution in the developing chick embryo brain, showed the presence of polyribosomal aggregates in the regions of 147 S and 206 S between the sixth and eighth day of incubation. After the 16th day of incubation the presence of heavier polyribosomal aggregates in the region of 259 S and 280 S was found. The injection of spermine or spermidine into the air space of embryos on the tenth day of incubation leads to a remarkable increase in the incorporation rate of [3H]formate into the ribosomes. Studies under similar experimental conditions, showed an increased radioactivity in the region of 147 S, 206 S, 259 S and 280 S in embryos injected with spermine or spermidine.

Rossoni C

Papers

POLYAMINES and NUCLEIC ACID METABOLISM DURING DEVELOPMENT OF CHICK EMBRYO BRAIN