共查询到20条相似文献,搜索用时 0 毫秒
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Xylem cell differentiation involves temporal and spatial regulation of secondary cell wall deposition. The cortical microtubules are known to regulate the spatial pattern of the secondary cell wall by orientating cellulose deposition. However, it is largely unknown how the microtubule arrangement is regulated during secondary wall formation. Recent findings of novel plant microtubule-associated proteins in developing xylem vessels shed new light on the regulation mechanism of the microtubule arrangement leading to secondary wall patterning. In addition, in vitro culture systems allow the dynamics of microtubules and microtubule-associated proteins during secondary cell wall formation to be followed. Therefore, this review focuses on novel aspects of microtubule dynamics leading to secondary cell wall patterning with a focus on microtubule-associated proteins. 相似文献
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Wood behavior is characterized by high sensibility to humidity and strongly anisotropic properties. The drying shrinkage along the fibers, usually small due to the reinforcing action of cellulosic microfibrils, is surprisingly high in the so-called tension wood, produced by trees to respond to strong reorientation requirements. In this study, nitrogen adsorption-desorption isotherms of supercritically dried tension wood and normal wood show that the tension wood cell wall has a gel-like structure characterized by a pore surface more than 30 times higher than that in normal wood. Syneresis of the tension wood gel explains its paradoxical drying shrinkage. This result could help to reduce technological problems during drying. Potential applications in biomechanics and biomimetics are worth investigating, considering that, in living trees, tension wood produces tensile growth stresses 10 times higher than that of normal wood. 相似文献
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Regulation of cell wall biosynthesis 总被引:5,自引:0,他引:5
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Deposition and organisation of cell wall polymers during maturation of poplar tension wood by FTIR microspectroscopy 总被引:1,自引:0,他引:1
To advance our understanding of the formation of tension wood, we investigated the macromolecular arrangement in cell walls by Fourier transform infrared microspectroscopy (FTIR) during maturation of tension wood in poplar (Populus tremula x P. alba, clone INRA 717-1B4). The relation between changes in composition and the deposition of the G-layer in tension wood was analysed. Polarised FTIR measurements indicated that in tension wood, already before G-layer formation, a more ordered structure of carbohydrates at an angle more parallel to the fibre axis exists. This was clearly different from the behaviour of opposite wood. With the formation of the S2 layer in opposite wood and the G-layer in tension wood, the orientation signals from the amorphous carbohydrates like hemicelluloses and pectins were different between opposite wood and tension wood. For tension wood, the orientation for these bands remains the same all along the cell wall maturation process, probably reflecting a continued deposition of xyloglucan or xylan, with an orientation different to that in the S2 wall throughout the whole process. In tension wood, the lignin was more highly oriented in the S2 layer than in opposite wood. 相似文献
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Ultra-structural organisation of cell wall polymers in normal and tension wood of aspen revealed by polarisation FTIR microspectroscopy 总被引:2,自引:0,他引:2
Polarisation Fourier transform infra-red (FTIR) microspectroscopy was used to characterize the organisation and orientation
of wood polymers in normal wood and tension wood from hybrid aspen (Populus tremula × Populus tremuloides). It is shown that both xylan and lignin in normal wood are highly oriented in the fibre wall. Their orientation is parallel
with the cellulose microfibrils and hence in the direction of the fibre axis. In tension wood a similar orientation of lignin
was found. However, in tension wood absorption peaks normally assigned to xylan exhibited a 90° change in the orientation
dependence of the vibrations as compared with normal wood. The molecular origin of these vibrations are not known, but they
are abundant enough to mask the orientation dependence of the xylan signal from the S2 layer in tension wood and could possibly come from other pentose sugars present in, or associated with, the gelatinous layer
of tension wood fibres. 相似文献
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Further observations on hydrolysis of the cell wall in the xylem 总被引:1,自引:0,他引:1
Dr. T. P. O'Brien 《Protoplasma》1970,69(1):1-14
Summary Hydrolyzed walls (birefringent, Periodic acid/Schiff negative, remnants of primary walls that also lack polyuronides with free carboxyl groups) are demonstrated in the primary xylem of wheat and bean leaves. Walls with similar properties have been found in the primary xylem of a variety of tissues from different species, and are believed to be ubiquitous. It is shown that the pit membrane of intervessel pits between tracheary elements of willow is also a hydrolyzed wall. Combined with the observation byLiese (1965) it seems likely that the removal of non-cellulosic polysaccharides from primary walls unprotected by lignin is a general phenomenon that occurs late in the autolysis of all tracheary elements. Parenchyma cells that abut autolyzing tracheary elements appear to react to hydrolytic attack in a number of ways that are illustrated and discussed. 相似文献
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EgMYB2, a new transcriptional activator from Eucalyptus xylem, regulates secondary cell wall formation and lignin biosynthesis 总被引:12,自引:0,他引:12
Goicoechea M Lacombe E Legay S Mihaljevic S Rech P Jauneau A Lapierre C Pollet B Verhaegen D Chaubet-Gigot N Grima-Pettenati J 《The Plant journal : for cell and molecular biology》2005,43(4):553-567
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C L Villemez 《Biochemical and biophysical research communications》1970,40(3):636-641
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Transcriptional regulation in wood formation 总被引:1,自引:0,他引:1
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The cell wall of the environmental pathogen Mycobacterium avium is important to its virulence and intrinsic antimicrobial resistance. To identify genes involved in cell wall biosynthesis, "transposome" insertion libraries were screened for mutants with altered colony morphology on medium containing the lipoprotein stain Congo red. Nineteen such mutants were isolated and mapped, including 10 with insertions in a functional island of cell wall biosynthetic genes that spans approximately 40 kb of the M. avium genome. 相似文献
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Antane S Caufield CE Hu W Keeney D Labthavikul P Morris K Naughton SM Petersen PJ Rasmussen BA Singh G Yang Y 《Bioorganic & medicinal chemistry letters》2006,16(1):176-180
Pulvinones were synthesized (>180) in arrays and evaluated as inhibitors of early stage cell wall biosynthesis enzymes MurA-MurD. Several pulvinones inhibited Mur enzymes with IC(50)'s in the 1-10 microg/mL range and demonstrated antibacterial activity against Gram-positive bacteria including methicillin-resistant Staphyloccus aureus, vancomycin-resistant Enterococcus faecalis, and penicillin-resistant Streptococcus pneumoniae. 相似文献