Plant cytoskeleton

Lloyd, C.W. (1987). The plant cytoskeleton The impact of fluorescence microscopy. Ann. Rev. Plant Physiol. 38, 119-139. 

Klink, V.P. and Wolniak, S.M. (2000) The efficacy of RNAi in the study of the plant cytoskeleton. Journal of Plant Growth Regulation 19, 371-384. 

Xu, P., Lloyd, C.W., Staiger, C.J., and Drbak, B.K., 1992, Association of phosphatidylinositol 4-kinase with the plant cytoskeleton. Plant Cell 4 941-951. 

Wasteneys G.O. and Yang Z. 2004. New views on the plant cytoskeleton. Plant Physiol 136 3884-3891. 

Microfilaments and Microtubules. There are two important classes of fibers found in the cytoplasm of many plant and animal ceUs that are characterized by nematic-like organization. These are the microfilaments and microtubules which play a central role in the determination of ceU shape, either as the dynamic element in the contractile mechanism or as the basic cytoskeleton. Microfilaments are proteinaceous bundles having diameters of 6—10 nm that are chemically similar to actin and myosin muscle ceUs. Microtubules also are formed from globular elements, but consist of hoUow tubes that are about 30 nm in diameter, uniform, and highly rigid. Both of these assemblages are found beneath the ceU membrane in a linear organization that is similar to the nematic Hquid crystal stmcture. 

As plant cells grow, they deposit new layers of cellulose external to the plasma membrane by exocytosis. The newest regions, which are laid down successively in three layers next to the plasma membrane, are termed the secondary cell wall. Because the latter varies in its chemical composition and structure at different locations around the cell, Golgi-derived vesicles must be guided by the cytoskeleton... 

Goddard, R.H., Wick, S.W., Silflow, C D., Snustad, D.P. (1994). Microtubule components of the plant cell cytoskeleton. Plant Physiol. 104, 1-6. 

Tiwari, S.C., Wick, S.M., Williamson, R.E., Gunning, B.E. (1984). Cytoskeleton and integration of cellular function in cells of higher plants. J. Cell Biol. 99,63S-69S. 

P. Bonfante, At the interface between mycorrhizal fungi and plants. The structural organization of cell wall, plasma membrane, and cytoskeleton Mycota, Vol. IX, Fungal Associations (B. Hock, ed.). Springer-Verlag. In press. 

The eukaryotes these include animals, plants, fungi and protozoa, the DNA of which is enclosed in a membrane-enclosed organelle (the cell nucleus). They have a cytoskeleton (a fine membrane-like network in the interior of the cell, which provides stability) and contain mitochondria. Higher plants, as well as algae, are equipped with chloroplasts for photosynthesis. 

Oxalate Ca(C00)2H20 Ca(C00)2-2H20 Whewellite 1 Weddellite I " Insect eggs Vertebrate stones. .Abundant in plants Deterrent Cytoskeleton Ca store... 

If the allelochemical is hydrophylic, it cannot enter into the cell and act from outside by binding with chemoreceptors. The compounds from allelopathically active plants may serve as chemosignals and their signalling occurs via alternative pathways (i) Chemoreceptor (sensors) — transducers (G-proteins) —> secondary messengers (Ca2+, cyclic AMP or GMP, inositol triphospate, etc) —> organelles or (ii) Chemoreceptor (sensors) —> ion channels —> action potential organelles, or (iii) Chemoreceptor (sensors) —> ion channels —> cytoskeleton— organelles (Roshchina, 2005 a). What is the effect of acted allelochemical on the pathways, could be analysed to study the effects of substances on separate sites of the transduction chain. 

Deloof A, Broeck JV, Jensen I. Hormones and the Cytoskeleton of Animals and Plants. International Review of Cytology (Jeon KW, ed.), Academic Press, New York, 1996. 

The family of eukaryotic Ras-like small GTPases may be divided into subfamilies, namely those of ARF, Rab, Ran, Ras, Rho, and Sar (ARF, RAB, RHO, RAS, RHO, SAR), which all contain representatives from fungi, plants, and metazoa. Consequently, these subfamilies and their cellular functions are likely to have emerged early in eukaryotic history. This implies that the last common ancestor of fungi, plants, and metazoa possessed vesicular transport (ARF and Sar), membrane trafficking (Rab), nuclear transport (Ran), signal transduction (Ras), and regulation of the actin cytoskeleton (Rho) functions. 

A characteristic feature of the SuSy isoforms is a conserved phosphorylated serine residue near the N-terminus [8-10]. In-vivo studies have demonstrated that phosphorylation and dephosphorylation direct the distribution of SuSy isoforms in the plant cell [10-12]. The soluble phosphorylated SuSy interacts with the actin cytoskeleton in the cytoplasm [13], and the dephosphorylated SuSy isoforms are targeted to the cell membrane to form complexes with other enzymes, e.g., glucan synthase, catalyzing cellulose biosynthesis from sucrose [4, 10, 14]. In this respect, recent studies on the dephosphorylated enzymes by cloning and expression of SMS genes in E. coli have shown differences in some biochemical features when compared to the enzymes isolated from the corresponding plant material. Recom-... 

Vinblastine is an alkaloid derived from the periwinkle plant Vinca rosea. Its mechanism of action involves inhibition of tubulin polymerization, which disrupts assembly of microtubules, an important part of the cytoskeleton and the mitotic spindle. This inhibitory effect results in mitotic arrest in metaphase, bringing cell division to a halt, which then leads to cell death. Vinblastine and other vinca alkaloids are metabolized by the liver P450 system, and the majority of the drug is excreted in feces via the biliary system. As such, dose modification is required in the setting of liver dysfunction. The main adverse effects are outlined in Table 54-4, and they include nausea and vomiting, bone marrow suppression, and alopecia. This agent is also a potent vesicant, and care must be taken in its administration. It has clinical activity in the treatment of Hodgkin s... 

The most abundant microfilaments are composed of fibrous actin (F-actin Fig. 7-10). The thin filaments of F-actin are also one of the two major components of the contractile fibers of skeletal muscle. There is actually a group of closely related actins encoded by a multigene family. At least four vertebrate actins are specific to various types of muscle, while two (P- and y-actins) are cytosolic.298 299 Actins are present in all animal cells and also in fungi and plants as part of the cytoskeleton. The microfilaments can associate to... 

Valster, A.H., Pierson, E.S., Valenta, R. et al. 1997. Probing the plant actin cytoskeleton during cytokinesis and interphase by profilin microinjection. Plant Cell 9 1815-1824. 

Disturbances of the cytoskeleton, DNA replication, and DNA topoisomerase, or DNA alkylation and intercalation usually lead to cell death by apoptosis [18] (Table 1.2). The cytotoxic properties are usually not specific for animals but also affect bacteria, fungi, other plants, and even viruses. Alkaloids thus defend plants against a wide diversity of enemies. They have the disadvantage that a producing plant could theoretically kill itself by its own poison. Compartmentation, target-site insensitivity, and other mechanisms (which are largely unknown) must have evolved to overcome such problems. 

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