Inhibition of RNA Synthesis and the Relationship between Nucleolar and Mitotic Cycles in Zea mays Root Meristems

The relationship between nucleolar and mitotic cycles has beendetermined after treatment of root apices of Zea mays with ethidiumbromide. In the meristematic regions of the stele the two cyclesare not much displaced in relation to each other except fora delay in the onset of the disorganization phase. A few nucleolipersist into metaphase and a few nuclei undergo an amitoticdivision. In the cap initials the drug greatly delays the onsetof disorganization of the nucleolus, which normally occurs beforeprophase in this region. It also delays the completion of reorganizationso that fully organized nucleoli are no longer available duringthe last half of telophase. In the quiescent centre the onsetof disorganization and the end of reorganization of the nucleoliare also delayed in relation to mitosis. There is no evidencefor a delay in the onset of reorganization in any region ofthe meristem. Some cells form multiple micronucleoli and this aberrant behaviouroccurs more often in the cap initials than elsewhere as doesamitotic division.     

Use of ultrasound to locate a "lost" tissue expander injection port

We have presented a rapid and reliable method of finding lost injection valves. (A frustrating footnote, however, is that 1 week later the port had again migrated and could not be located. Since the further anticipated gain was marginal, the bladder was already nearly expanded, and the expense for repeated ultrasound was a consideration, no further attempts were made to locate this port by ultrasound for further filling).     

Purification of a 20 kDa phosphoprotein from epithelial cells and identification as a myosin light chain. Phosphorylation induced by enteropathogenic Escherichia coli and phorbol ester

Previous studies on the mechanism of enteropathogenic Escherichia coli (EPEC) infection have revealed an increase in the phosphorylation state of a number of proteins in human laryngeal HEp-2 cells. The most prominent was an acidic phosphoprotein(s) of Mr 20-21 kDa. The present study reports: (a) a simple method for purification of phosphorylated 20 kDa protein; (b) identification of the 20 kDa phosphoprotein as myosin light chain; and (c) that the phorbol ester, TPA, also increased the phosphorylation of the 20 kDa myosin light chain. In contrast to the effects of EPEC, TPA stimulation resulted in the dissociation of myosin from the cytoskeleton to the cytosol.