Positive regulation in a eukaryote, a study of the uaY gene of Aspergillus nidulans. II. Identification of the effector binding protein.

In this publication we report the identification of a protein likely to be coded by uaY, a regulatory gene in the ascomycete Aspergillus nidulans. uaY is a positive control gene necessary for the expression of at least eight unlinked structural genes involved in purine uptake and degradation (Scazzocchio and Gorton 1977). The physiological effector of the uaY system is uric acid, while some of its thioanalogs serve as gratuitous inducers. Effector binding proteins were detected by binding to 2-thiouric acid after phosphocellulose column chromatography, or as uric acid binding fractions after DNA-cellulose column chromatography. Two binding peaks are present in mycelial extracts purified by either method. These are missing in a putative small deletion of the uaY gene. A "leaky" mutation, uaY109 described in detail elsewhere (Scazzocchio et al. 1980) shows only one peak. The wild type peaks eluted at 55 mM NaC1 and at 720 mM NaCl while the peak present in uaY109 is eluted at 120 mM NaC1. This implies that at least one peak represents a protein coded by the uaY gene. The major peak was analysed by equilibrium dialysis experiments. These establish a Kdiss approximately 2 X 10(-7) and a minimum number of binding sites of 3 X 10(-14) moles/mg of soluble protein in a crude extract derived from protoplast lysis. An extract from a strain carrying the uaY207 deletion, purified blind, lacks any binding activity in the equilibrium dialysis cell.

[Topographic forms of herniated lumbar discs. Contribution of saccoradiculographie and zonographie]. / Les formes topographiques de hernies discales. Apports de la saccoradiculographie avec zonographie

The clinical signs of herniated lumbar disc do not always allow to settle their level. Therefore authors add, to sacco-radiculography with standard plates, frontal zonographic sections. Then, they study radiographic findings and segregate some particular topographic forms of herniated discs: 1) with fragment behind verebral body, 2) with deviated root outside the disc herniation, 3) in front of the lamina and behind the root. Some of them have their own clinical signs, especially paralysed forms of L5 sciatic with abolition of achilean reflexe. Further more they propose hemilaminectomy for total removal of herniated lumbar discs with fragment behind the vertebral body. They conclude to advantage of usually making a saccoradiculography with the dimer iothalamate of methyl glucamine (Dimer X) before each operation.