1,721,270 research outputs found
Verso un'agricoltura di qualità:il ritorno alla terra e al territorio
No full textL'articolo prende in esame l'evoluzione della agricoltura biologica in Italia e in Toscana in particolare dagli anni Novanta ad oggi. Il settore agricolo sta vivendo un nuovo periodo di sviluppo in quanto risponde alla esigenza di prodotti di qualità che garantiscono la sicurezza alimentare e prodotti ottenuti con pratiche ecocompatibili. La Toscana è una regione privilegiata in tal senso
Pollen tube taxol dependent structures co-assemble with neuronal HMW MAPs (MAP2)
No full textPollen tube microtubules (MTs) are as dynamic as animal MTs and they may interact with plasma membrane, endoplasmic reticulum, Golgi apparatus, mitocondria and a variety of cytoplasmic proteins. Bridges connecting MTs to each other and to membranes have been documented in pollen tubes by electron microscopy; however, the biochemical and molecular nature of these linkages is not known. In other cell types interaction between organelles and MTs require the participation of Microtubule-Associated Proteins (MAPs) that bridge the cytoskeleton to these organelles. Although biochemical documentation of such bridging MAPs in plant cells is lacking, it is reasonable to assume, by analogy with the animal systems, that specialized MAPs regulate MTs polymerization and dynamic in pollen tube. As a first step toward testing this hypothesis, the ability of Nicotiana tabacum pollen tube taxol-stabilized MTs to bind mammalian brain High Molecular Weight MAPs (HMWMAPs)(MAP2) was tested. This association analysis revealed the presence of mammalian MAP2-binding sites on pollen tube taxol-induced structures suggesting that the association presumably occurs at conserved domains on the tubulin molecules
History and prospects of plant sexual reproduction congresses, the IASPRR and sexual plant reproduction
No full textMicrotubule motor proteins and the organization of the pollen tube cytoplasm
No full textMolecular motors are molecules that drive a wide range of activities (for example, organelle movement, chromosome segregation, and flagellar movement) in cells. Thus, they play essential roles in diverse cellular functions. Understanding their structures, mechanisms of action and different roles is therefore of great practical importance. The role of microtubules during pollen tube growth is presently not identified, nor are basic properties. We do not know, for example, where microtubules are organized, the extent of microtubule dynamics, and the polarity of microtubules in the pollen tube. Roles of microtubules and related motors in organelle trafficking are not clear. Regardless of scarce information, microtubule-based motors of both the kinesin and dynein families have been identified in the pollen tube. Most of these microtubule motors have also been found in association with membrane-bounded organelles, which suggest that these proteins could translocate organelles or vesicles along microtubules, The biochemical features of these proteins are typical of the motor protein class. Immunofluorescence microscopy of pollen tubes probed with antibodies that cross-react with microtubule motors indicate that these proteins are localized in different regions of the pollen tuber therefore, they could have different roles. Although a number of microtubule motors have been identified in the pollen tube, the role of these proteins during pollen tube germination and growth or organelle movement is not yet recognized, as tube elongation and organelle movement in the pollen tube depend mostly on actin filaments. In the effort to understand the specific role that microtubules and related motors have in the pollen tube, it is therefore necessary to identify the molecular machinery that interacts with microtubules. Furthermore, it is crucial to clearly establish the types of interaction between organelles and microtubules. This review summarizes the current state of the art on microtubule motors in the pollen tube, mainly surrounding the putative roles of microtubule motors in organelle movement and cytoplasmic organization. Some hypotheses and speculations are also presented
Accumulation and post-translational modifications of plant tubulins
No full textThe microtubular cytoskeleton of plant cells provides support for several functions (including the anchoring of proteins, assembly of the mitotic spindle, cytoplasmic streaming and construction of cell walls). Both a- and b-tubulins are encoded through multigene families that are differentially expressed in different organs and tissues. To increase the variability of expression, both protein subunits are subjected to post-translational modifications, which could contribute to the assembly of specific microtubule structures. This review aims to highlight the role of specific post-translational modifications of tubulin in plant cells. We initially describe the expression and accumulation of a- and b-tubulin isoforms in different plants and at different stages of plant development. Second, we discuss the different types of post-translational modifications that, by adding or removing specific functional groups, increase the isoform heterogeneity and functional variability of tubulin. Modifications are proposed to form a 'code' that can be read by proteins interacting with microtubules. Therefore, the subpopulations of microtubules may bind to different associated proteins (motor and non-motor), thus creating the physical support for various microtubule functions
A universal and rapid protocol for protein extraction from recalcitrant plant tissues for proteomic analysis
No full textA simple and universally applicable protocol for extracting high-quality proteins from recalcitrant plant tissues is described. We have used the protocol with no modification, for a wide range of leaves and fruits. In all cases, this protocol allows to obtain good electrophoretic separation of proteins. As the protocol is rapid, universal, and compatible with silver staining, it could be used for routine protein extraction from recalcitrant plant tissues for proteomic analysi
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