Treatment of HeLa cells with low intensity ultrasound and two cytostatic drugs, cycloplatin and methotrexate, resulted in a partial disassembly of microtubules and microfilaments. This disassembly was due to depolymerization and subsequent erroneous repolymeration of essential cytoskeletal proteins, resulting in formation of unusual arrangements, mainly small, granule-like structures. The combined action of ultrasound and cytostatics had a synergistic effect dependent on both the concentration of the drug and the time of sonication. The demonstrated changes in the cytoskeleton are considered to be non-specific to ultrasound treatment, reflecting only an altered vital state of the treated cells.

• MeSH
• biopolymery MeSH
• HeLa buňky účinky léků   ultrastruktura   MeSH
• lidé MeSH
• methotrexát farmakologie   toxicita   MeSH
• mikrofilamenta účinky léků   ultrastruktura   MeSH
• mikrotubuly účinky léků   ultrastruktura   MeSH
• organoplatinové sloučeniny farmakologie   toxicita   MeSH
• protinádorové látky farmakologie   MeSH
• ultrazvuk * škodlivé účinky   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• biopolymery MeSH
• cycloplatam MeSH Prohlížeč
• methotrexát MeSH
• organoplatinové sloučeniny MeSH
• protinádorové látky MeSH

The relationship between cytoskeleton and morphology of cumulus granulosa cells in expanding bovine oocyte-cumulus complexes (OCCs) cultured in vitro has been investigated by the means of indirect immunofluorescence and transmission electron microscopy. The round-shaped cells in unstimulated control OCCs displayed a homogeneous distribution of cytoskeletal networks and cytoplasmic organelles. Luteinizing hormone (LH) stimulation caused the redistribution of microfilaments (MFs), accelerated the development of Golgi apparatus, and led to the generation of lipid droplets in cumulus cells. These changes culminated in the elongation and polarization of cumulus cells and in the extension of the cytoplasmic networks of microtubules (MTs) and intermediate filaments (IFs) into the newly formed cytoplasmic projections. The culture of OCCs in the presence of microfilament disruptor cytochalasin B prevented cumulus expansion, formation of cellular projections and cell elongation and suppressed the development of the Golgi apparatus. On the contrary, cytochalasin had no effect on the abundance and distribution of lipid droplets and on the integrity of IFs and MTs. The present data support the hypothesis that the response of cumulus granulosa cells to LH is partially mediated by F-actin.

• MeSH
• aktiny chemie   MeSH
• cytochalasin B farmakologie   MeSH
• elektronová mikroskopie MeSH
• fluorescenční protilátková technika MeSH
• folikulární buňky ultrastruktura   MeSH
• intermediární filamenta fyziologie   MeSH
• luteinizační hormon farmakologie   MeSH
• mikrofilamenta fyziologie   MeSH
• mikrotubuly fyziologie   MeSH
• oocyty účinky léků   fyziologie   ultrastruktura   MeSH
• skot anatomie a histologie   MeSH
• zvířata MeSH
• Check Tag
• skot anatomie a histologie   MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• aktiny MeSH
• cytochalasin B MeSH
• luteinizační hormon MeSH

• MeSH
• astrocyty ultrastruktura   MeSH
• cytoskelet ultrastruktura   MeSH
• elektronová mikroskopie MeSH
• hypothalamus ultrastruktura   MeSH
• kočky MeSH
• křečci praví MeSH
• mikrotubuly ultrastruktura   MeSH
• mitochondrie ultrastruktura   MeSH
• zvířata MeSH
• Check Tag
• kočky MeSH
• křečci praví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Tumour cell plasma in 4 out of 8 bronchial carcinoids was found to contain sphere-shaped formations of microfilaments different in nature from tonofilaments, myofilaments or amyloid fibrils. The filamentous structures were closely related to agranular endoplasmic reticulum with the occassional inclusion of endocrine granules of type Pa cells. In the discussion prt, the author refers to similar structures in other tumours arising from cells of the diffuse endocrine system, and in some of the lung carcinomas.

• MeSH
• adenom ultrastruktura   MeSH
• cytoskelet ultrastruktura   MeSH
• karcinoid ultrastruktura   MeSH
• lidé MeSH
• nádory průdušek ultrastruktura   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH

Distension is a regular mechanical stimulus in gastrointestinal (GI) tract. This study was designed to investigate the effect of hypotonic stress on pacemaking activity and determine whether actin microfilament is involved in its mechanism in cultured murine intestinal interstitial cells of Cajal (ICCs) by using whole-cell patch-clamp and calcium imaging techniques. Hypotonic stress induced sustained inward holding current from the baseline to -650+/-110 pA and significantly decreased amplitudes of pacemaker current. Hypotonic stress increased the intensity of basal fluorescence ratio (F/F0) from baseline to 1.09+/-0.03 and significantly increased Ca(2+) oscillation amplitude. Cytochalasin-B (20 microM), a disruptor of actin microfilaments, significantly suppressed the amplitudes of pacemaker currents and calcium oscillations, respectively. Cytochalasin-B also blocked hypotonic stress-induced sustained inward holding current and hypotonic stress-induced increase of calcium oscillations. Phalloidin (20 microM), a stabilizer of actin microfilaments, significantly enhanced the amplitudes of pacemaker currents and calcium oscillations, respectively. Despite the presence of phalloidin, hypotonic stress was still able to induce an inward holding current and increased the basal fluorescence intensity. These results suggest that hypotonic stress induces sustained inward holding current via actin microfilaments and the process is mediated by alteration of intracellular basal calcium concentration and calcium oscillation in cultured intestinal ICCs.

• MeSH
• biologické hodiny fyziologie   MeSH
• buněčný převod mechanických signálů fyziologie   MeSH
• gastrointestinální motilita fyziologie   MeSH
• kultivované buňky MeSH
• mikrofilamenta metabolismus   MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• osmotický tlak fyziologie   MeSH
• telocyty fyziologie   MeSH
• vápníková signalizace fyziologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

In many eukaryotic lineages, the RHO clade of small GTPases controls microfilament dynamics by direct binding to formin family actin nucleators. A new study in plants reveals that formin activity can also be regulated by a RHO cofactor rather than the GTPase itself.

• MeSH
• aktiny metabolismus   MeSH
• forminy * metabolismus   genetika   MeSH
• mikrofilamenta metabolismus   MeSH
• mikrofilamentové proteiny metabolismus   genetika   MeSH
• Rho proteiny vázající GTP metabolismus   genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• aktiny MeSH
• forminy * MeSH
• mikrofilamentové proteiny MeSH
• Rho proteiny vázající GTP MeSH

Mast cell activation mediated by the high affinity receptor for IgE (FcεRI) is a key event in allergic response and inflammation. Other receptors on mast cells, as c-Kit for stem cell factor and G protein-coupled receptors (GPCRs) synergistically enhance the FcεRI-mediated release of inflammatory mediators. Activation of various signaling pathways in mast cells results in changes in cell morphology, adhesion to substrate, exocytosis, and migration. Reorganization of cytoskeleton is pivotal in all these processes. Cytoskeletal proteins also play an important role in initial stages of FcεRI and other surface receptors induced triggering. Highly dynamic microtubules formed by αβ-tubulin dimers as well as microfilaments build up from polymerized actin are affected in activated cells by kinases/phosphatases, Rho GTPases and changes in concentration of cytosolic Ca(2+). Also important are nucleation proteins; the γ-tubulin complexes in case of microtubules or Arp 2/3 complex with its nucleation promoting factors and formins in case of microfilaments. The dynamic nature of microtubules and microfilaments in activated cells depends on many associated/regulatory proteins. Changes in rigidity of activated mast cells reflect changes in intermediate filaments build up from vimentin. This review offers a critical appraisal of current knowledge on the role of cytoskeleton in mast cells signaling.

• Klíčová slova
• actins, intermediate filaments, mast cell activation, microfilaments, microtubules, signal transduction, tubulins, vimentin,
• Publikační typ
• časopisecké články MeSH

Plasmolysis is a typical response of plant cells exposed to hyperosmotic stress. The loss of turgor causes the violent detachment of the living protoplast from the cell wall. The plasmolytic process is mainly driven by the vacuole. Plasmolysis is reversible (deplasmolysis) and characteristic to living plant cells. Obviously, dramatic structural changes are required to fulfill a plasmolytic cycle. In the present paper, the fate of cortical microtubules and actin microfilaments is documented throughout a plasmolytic cycle in living cells of green fluorescent protein (GFP) tagged Arabidopsis lines. While the microtubules became wavy and highly bundled during plasmolysis, cortical filamentous actin remained in close vicinity to the plasma membrane lining the sites of concave plasmolysis and adjusting readily to the diminished size of the protoplast. During deplasmolysis, cortical microtubule re-organization progressed slowly and required up to 24 h to complete the restoration of the original pre-plasmolytic pattern. Actin microfilaments, again, recovered faster and organelle movement remained intact throughout the whole process. In summary, the hydrostatic skeleton resulting from the osmotic state of the plant vacuole "overrules" the stabilization by cortical cytoskeletal elements.

• Klíčová slova
• Arabidopsis hypocotyl, GFP-ABD, GFP-MAP4, GFP-TUA6, actin microfilaments, cytoskeleton, deplasmolysis, microtubules, plasmolysis,
• Publikační typ
• časopisecké články MeSH

Plant cytoskeleton consists of two major networks of protein polymers, actin microfilaments (AFs) and microtubules (MTs). These networks perform numerous functions that are essential for cell division and for maintaining the integrity of cytoplasm required for intracellular transport and cell shape. Besides the more or less indirect cooperation between AFs and MTs, their direct interactions through specific physically interacting proteins has been well described in yeast, nematodes, insect and animal cells. Recently, promising candidates for corresponding homologous proteins have been identified in plants, although there is still lack of functional evidence for these interactions. Here we summarize recent advances in our knowledge about the candidate proteins or protein complexes that interact with both AFs and MTs and their role in fundamental cellular and developmental processes.

• MeSH
• aktiny fyziologie   MeSH
• biologický transport MeSH
• cytokineze MeSH
• kineziny metabolismus   MeSH
• mikrofilamenta fyziologie   MeSH
• mikrotubuly fyziologie   MeSH
• mitóza MeSH
• rostlinné buňky * MeSH
• rostlinné proteiny metabolismus   MeSH
• tvar buňky MeSH
• zvětšování buněk MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• aktiny MeSH
• kineziny MeSH
• rostlinné proteiny MeSH

We developed a simple and reliable technique for immunofluorescence detection of F-actin on microtome sections of plant tissues. For the first time, large numbers of plant cells from various tissues that pass through their developmental stages could be consistently visualized on one section from plant organs. n-Maleimidobenzoic acid N-hydroxysuccinimide ester-pretreated and formalin-fixed segments of plant roots and shoots were embedded in low melting point ester wax at 37C and sectioned on a microtome. After dewaxing and rehydration, microfilaments were visualized by indirect immunofluorescence technique with a monoclonal anti-actin antibody. The technique has been successfully used for visualization of tissue- and development-specific F-actin arrays in cells of Zea mays and Lepidium sativum root tips and of maize stem nodes.

• MeSH
• aktiny analýza   MeSH
• fixace tkání MeSH
• fluorescenční protilátková technika nepřímá * MeSH
• kořeny rostlin chemie   MeSH
• kukuřice setá MeSH
• mikrofilamenta chemie   ultrastruktura   MeSH
• stonky rostlin chemie   MeSH
• teplota MeSH
• zalévání tkání MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• aktiny MeSH