An actin network is present in the cytoplasm throughout the cell cycle of carrot cells and associates with the dividing nucleus.

Abstract

Abstract. We have studied the F-actin network in cycling suspension culture cells of carrot (Daucus carom L.) using rhodaminyl lysine phallotoxin (RLP).In addition to conventional fixation with formaldehyde, we have used two different nonfixation methods before adding RLP: extracting cells in a stabilizing buffer; inducing transient pores in the plasma membrane with pulses of direct current (electroporation). These alternative methods for introducing RLP revealed additional features of the actin network not seen in aldehyde-fixed cells. The three-dimensional organization of this network in nonflattened cells was demonstrated by projecting stereopairs derived from through-focal series of computer-enhanced images.

The Organization of the Actin Cytoskeleton in Vertical and Graviresponding Primary Roots of Maize

“…This organization was similar to the organization of MFs in elongating cells of several vascular plants (Parthasarathy et al, 1985) and vascular tissues of gymnosperm (Pesacreta et al, 1982) and maize roots (Vaughan and Vaughn, 1987). Other studies, however, have reported the occurrence of fine, more or less parallel cortical MFs in elongating tobacco protoplasts (Hasezawa et al, 1989), in carrot (Traas et al, 1987) and alfalfa suspension cells (Seagull et al, 1987), as well as in elongating cells of pea roots (Hush and Overall, 1992). In the present study, we demonstrated the occurrence of thin, more fragile bundles of either longitudinally or irregularly oriented MFs in elongating cells of maize roots in addition to the thick bundles.…”

“…In the present study, we demonstrated the occurrence of thin, more fragile bundles of either longitudinally or irregularly oriented MFs in elongating cells of maize roots in addition to the thick bundles. Other protocols for visualization of the actin cytoskeleton used pretreatments with MBS prior to aldehyde fixation (Sonobe and Shibaoka, 1989) or eliminated formaldehyde fixation (Hush and Overall, 1992 transverse cortical MFs in elongating maize cells as has been reported for other systems (Seagull et al, 1987;Traas et al, 1987;Hasezawa et al, 1989), but often resulted in fewer and fragmented MFs in epidermal and cortical cells. Similarly, MBS cross-linking or direct permeabilization with detergents were ineffective in preserving MFs in onion roots (Liu and Palevitz, 1992).…”

“…These vesicles have been proposed to move along MFs that are aligned parallel to the pollen tube or root hair (Sievers and Schnepf, 1981). In elongating cells of vascular plants, MFs are arranged as thick longitudinal cables connected to a finer array of peripheral MFs that are either oriented longitudinally (Parthasarathy et al, 1985) or transversely (Seagull et al, 1987;Traas et al, 1987;Hasezawa et al, 1989). The actin cytoskeleton may have important implications for cell elongation.…”

Visualization and analysis of actin cytoskeleton organization in plants

“…Historically, the first methods used to visualize the actin cytoskeleton in plants under an optical microscope were staining of plant tissues with fluorescently labelled actin-binding phallotoxins after chemical fixation (Parthasarathy, Perdue, Witztum, and Alvernaz, 1985;Kakimoto and Shibaoka, 1987;Traas et al, 1987), and direct microinjection of such probes into cells (Cleary, 1995). In contrast to microtubules, which may be visualized by injection of fluorescently labelled tubulin, the applications of G-actin chemically derivatized in the same manner were not successful.…”

Preprophase band formation and cortical division zone establishment: RanGAP behaves differently from microtubules during their band formation

“…[10][11][12][13][14][15] Several types of molecules, such as actins, MT-associated proteins (MAPs), kinesins, cdk/cyclins and other proteins have also been reported in PPBs. [16][17][18] Actins are most well-known components of PPB, [19][20][21] and the drug studies have suggested their involvement in the narrowing of the MT band. 22 Several MT associated proteins (MAPs) are also located in the PPB 18 and studies of the loss-of-function mutants have shown that the MICROTUBULE ORGANIZATION 1 (MOR1) and CLIP-associated proteins (CLASP) are involved in the MT band organization.…”