System analysis and nucleic acid sequence banks

The mass of published nucleic acid sequence data has required the design of several computerized data bases. We show that this activity is related to the methodology of System Analysis and that data bases are a means of modeling biological knowledge. As an example, the ACNUC data base we have created is presented.     

Changes in ornithine transcarbamylase activity and protein level during perinatal period in rat liver. Effects of actinomycin D

Ornithine transcarbamylase activity and immunoreactive enzyme level are compared during perinatal period and in adult rat. Ornithine transcarbamylase activity regularly rises during late fetal period and presents a marked increase 24 hours after birth. Immunoreactive enzyme level does not correlate with this developmental pattern. Ornithine transcarbamylase level increases from 0.06 mg on day 19.5 of pregnancy to 0.417 mg/g liver on day 21.5 and remains constant after birth (0.418 mg/g liver). These results suggest that inactive mitochondrial ornithine transcarbamylase accumulates before birth and that the postnatal increase in enzyme activity is mainly associated with an activation. Furthermore, the paradoxical effect of actinomycin D on ornithine transcarbamylase activity is associated with an increase in enzyme level (about 25%).