Marcia M. Falconer

Learn More
By using fluorescently labeled phalloidin we have examined, at the light microscope level, the three-dimensional distribution and reorganization of actin-like microfilaments (mfs) during plant cell cycle and differentiation. At interphase, mfs are organized into three distinct yet interconnected arrays: fine peripheral networks close to the plasma membrane;(More)
Xylogenesis has been studied in primary suspension cultures ofZinnia elegans L.: The wall patterns produced in culture closely resemble those described for intact tissues (annular, spiral, reticulate, scalariform, pitted). Using fluorescence microscopy and immuno-cytochemical techniques we have followed both the changes in wall deposition and microtubule(More)
InZinnia elegans tissue cultures, cortical microtubules reorient from longitudinal to transverse arrays as the culture age increases and before differentiation of tracheary elements is visible. The orientation of microtubules, in the period just before visible differentiation, determines the direction of the secondary wall bands in forming tracheary(More)
A one hour exposure to 3 μM amiprophos-methyl (APM) depolymerizes all MT arrays in cells from higher plant suspension cultures. On removal of APM, MT repolymerization sites are detected using immunofluorescent staining. During interphase, Mt arrays return uniformly dispersed across the cell cortex with transverse arrays in elongated cells and random arrays(More)
In plant cell suspension cultures sensitive to the herbicide amiprophos-methyl (APM), 1 to 3 μM APM completely depolymerized both cortical and mitotic microtubule (MT) arrays in 1 hour. In comparison, a 2 hour application of 3 mM colchicine had no effect on MT arrays. Recovery from APM treatment occurred as early as 5 minutes after removal of APM. Short,(More)
Two posttranslational modifications of alpha-tubulin, acetylation and detyrosination, are associated with stable microtubule (MT) populations, including those of neuronal processes. We have used a pluripotent embryonal carcinoma cell line, P19, to investigate changes in MT isotype and stability found in MT arrays during neurogenesis. This cell line has an(More)
Pluripotent P19 embryonal carcinoma (EC) cells were differentiated along the neuronal and muscle pathways. Comparisons of class I, II, III, and IV beta tubulin isotypes in total and colchicine-stable microtubule (MT) arrays from uncommitted EC, neuronal, and muscle cells were made by immunoblotting and by indirect immunofluorescence microscopy. In(More)
The effects of methylmercury (MeHg) on microtubules (MTs) in differentiating neurons derived from retinoic acid-induced embryonal carcinoma (EC) cells in culture were examined by immunofluorescence microscopy. Undifferentiated EC cells contained mostly kinetically labile tyrosinated (TYR) MTs which extended from the centrosome and a small population of(More)
InZinnia suspension cultures, two general categories of tracheary element (TE) secondary wall patterns can be distinguished: bands and webs. Band patterns are found in elongated cells or regions of cells, web patterns in isodiametric cells or regions of cells. Interphase cortical microtubule arrays, organized before overt differentiation occurs, determine(More)
Microtubule (Mt) populations show large differences in dynamic properties (i.e., turnover rates) among cell types, and even within the same cell type at different stages of the cell cycle or stages of differentiation. These differences in dynamic properties are correlated with altered sensitivity to Mt-disassembling drugs (e.g. colchicine) which bind(More)