Polysaccharides and Lignin

Freudenberg, Karl

doi:10.1146/annurev.bi.08.070139.000501

Cited by 32 publications

(22 citation statements)

References 38 publications

(47 reference statements)

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“…Monopbenol, tbe benzenediols (catecbol, resorcinol, quinol), guaiacol, tbe benzenetriois (pyrogallol, pbloroglucinol), orcinol, gallic acid, and trans-cinnamic acid failed to yield color-producing deposits in tbe tissues, bence gave negative tests for lignin. Tbese findings are consistent witb tbe early suggestions of Freudenberg (1939) tbat eugenollike units serve as lignin-precursors.…”

Section: Formation Of Lignins By Elodeasupporting

confidence: 90%

Studies on the Biosynthesis of Lignins

Siegel

1954

Physiologia Plantarum

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Freudenberg et at (t952) demonstrated the polymerization of coniferyl atcotiol in tbe presence of oxidizing enzymes from Araucaria. Addition of bydrogen peroxide increased tbe yietd of polymer, and tbe presence of peroxidase in tbe enzyme preparation was indicated.Siegel (1953) reported tbat eugenol, incubated witb tissues of tbe Red Kidney bean embryo, was converted into a lignin-bke material wben peroxide was supplied in tbe reaction mixture. Cbaracteristic lignin color reactions were obtained and tbe product was isolated in measurable quantities by standard procedures used in lignin determination (Norman, 1937).Formation of lignin from eugenol was rapid (2.5-5.0 mg./lOO mg. dry matter in 3 bours), HaOg-dependent, and effected by a cyanide-inbibited tbermolabile catalyst. Tbe obvious interpretation, tbat tbe enzyme peroxidase participated in tbe lignin-forming process, was supported by agreement between sites of intense deposition of tbe presumptive lignin and tbose of bigb peroxidase activity (fibrovascular ring, meristems).It was subsequently observed tbat sections from internodes of Elodea densa were bigbly active in converting eugenol into lignin; tbat substances otber tban eugenol and tbymol serve as lignin precursors, and tbat tbe properties of tbe material formed almost certainly place it witb naturally occurring lignins. '• Present address:

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Section: Formation Of Lignins By Elodeasupporting

confidence: 90%

Studies on the Biosynthesis of Lignins

Siegel

1954

Physiologia Plantarum

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“…At this time the Reticular Hypothesis in particular received very strong support, though Pfeffer in 1890 sounded a warning note in denying that protoplasm could be such a firm, continuous and permanently rigid structure as it was apparently coming to be. Again, Schwartz (1887) pointed out that a reticulate appearance, identical with that said to be visible in protoplasm, could be induced in the white of INTRODUCTION AND HISTORICAL BACKGROUND 9 an egg, and attempted to revive the older fluid theory by ascribing the reticular appearance to precipitations at certain places and under certain conditions. If this can be taken to imply a submicroscopic fibrillar organization which "condenses" into a grosser structure during coagulation, then this is a close approach to the modern view.…”

Section: Advances Following Improved Techniquesmentioning

confidence: 99%

“…S (limiting) Spacing No ence all fibres whose spirals are flatter than 5= 73-5, say, for the [3][4][5][6][7][8][9] arc, or than the corresponding figure for the other two arcs, will give two meridional spots instead of four lateral arcs. In a mixture of fibres in which 5 varies sufficiently widely, therefore, one would expect spirals flatter than those given in the above table to contribute to the meridional arc, and the 3-9 arc should therefore appear intense out of proportion to the 5-4 and 6-1 arcs.…”

Section: )mentioning

confidence: 99%

The molecular architecture of plant cell walls

Preston¹

1952

127

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THE MOLECULAR ARCHITECTURE OF PLANT CELL WALLS types he saw and figured for the first time (he was the first to use the term parenchyma for instance) he gave early attention to the walls of vessels. On mechanical treatment of these he found them to unwind like flat ribbons and of these ribbons he says (1682) (Plate I): ... the Vessles, oftentimes, unroave in the form of a Plate. As if we should imagine a piece of fine narrow Ribband, to be woutf d spirally, and Edg to Edg, round about a Stick; and so, the Stick being drawn out, the Ribband to be left in the Figure of a Tube, answerable to an Aer-Vessel. For that which, upon the unroaving of the Vessel, seems to be a Plate, or one single Piece, is, as it were, a Natural Ribband, consistmg of several pieces, that is, a certain number of Threds or Round Fibres, standing parallel, as the Threds do in an Artificial Ribband. And as in a Ribband, so here, the Fibres which make the Warp, and which are Spirally continu'd; although they run parallel, yet are not coalescent; but contained together, by other Transverse Fibres in the place of a Woof. He became convinced that all other cell types follow this structure, and concluded in general that the threads in parenchyma cell walls lie horizontally while those of fibres lie vertically. Let us notice particularly the fineness to which he considered these threads could be split. So in the Pith of a Bulrush of the Common Thistle, and some other Plants; not only the threds of which the Bladders; but also the single Fibres, of which the Threds are composed; may sometimes with the help of a good Glass, be distinctly seen. Yet one of these Fibres, may reasonably be computed to be a Thousand times smaller than an Horse-Hair. This latter estimate can hardly be accepted since the fibres would then have been ofthe order of 0-1 or 0-2/i in diameter. It does seem reasonable to assume, however, that Grew had seen threads grading in fineness down to the limits observable. Some two hundred years later Sachs, the foremost plant physiologist of his time, was to ridicule these suggestions made by Grew; yet it is very instructive to examine his figures, of which one is presented in Plate I, in the light of modern observations with an electron microscope (Frontispiece). It is always easy, of course, to read modern ideas into older and vaguer writings, but here Grew expresses himself so unequivocally that one can hardly avoid the conclusion that this interpretation, in terms of what we would now call fibrils, was inspired vision. We are to see the idea of fibrillar structure turning up again and again in the years that followed, both in the wall and in the protoplasm, and equally often being ridiculed. Grew was undoubtedly an acute observer; among other things, he realized that the walls of parenchyma cells were complete, without perforations, a point structures was any attempt made at an understanding of submicroscopic features or therefore at an impression of the processes of growth which such knowledge alone can give. This was, however, soon ...

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“…As mentioned above, the ability of CDs to form intermolecular complexes with other organic and inorganic molecules was already known to Schardinger who used the complexation ability of CDs with chloroform and alcohols for their precipitation and, moreover, the complexation with molecular iodine for the distinction between two dextrins which he named α and β [22]. Freudenberg was the first who assumed that these complexes are of the inclusion type [27,28]. The first direct evidence for molecular inclusions by CDs in the solid state came from X-ray crystallography.…”

Section: Brief Historical Tour About Cyclodextrinsmentioning

confidence: 99%

Native and substituted cyclodextrins as chiral selectors for capillary electrophoresis enantioseparations: Structures, features, application, and molecular modeling

Peluso

Chankvetadze

2021

Electrophoresis

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CDs are cyclic oligosaccharides consisting of α‐d‐glucopyranosyl units linked through 1,4‐linkages, which are obtained from enzymatic degradation of starch. The coexistence of hydrophilic and hydrophobic regions in the same structure makes these macrocycles extremely versatile as complexing host with application in food, cosmetics, environmental, agriculture, textile, pharmaceutical, and chemical industries. Due to their inherent chirality, CDs have been also successfully used as chiral selectors in enantioseparation science, in particular, for CE enantioseparations. In the last decades, multidisciplinary approaches based on CE, NMR spectroscopy, X‐ray crystallography, microcalorimetry, and molecular modeling have shed light on some aspects of recognition mechanisms underlying enantiodiscrimination. With the ever growing improvement of computer facilities, hardware and software, computational techniques have become a useful tool to model at molecular level the dynamics of diastereomeric associate formation to sample low‐energy conformations, the binding energies between the enantiomer and the CD, and to profile noncovalent interactions contributing to the stability of CD/enantiomer association. On this basis, the aim of this review is to provide the reader with a critical overview on the applications of CDs in CE. In particular, the contemporary theory of the electrophoretic technique and the main structural features of CDs are described, with a specific focus on techniques, methods, and approaches to model CE enantioseparations promoted by native and substituted CDs. A systematic compilation of all published literature has not been attempted.

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Polysaccharides and Lignin

Cited by 32 publications

References 38 publications

Studies on the Biosynthesis of Lignins

Studies on the Biosynthesis of Lignins

The molecular architecture of plant cell walls

Native and substituted cyclodextrins as chiral selectors for capillary electrophoresis enantioseparations: Structures, features, application, and molecular modeling

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