Solid-state 13C and 1H spin diffusion NMR analyses of the microfibril structure for bacterial cellulose

Masuda, Kenji; Adachi, Masayuki; Hirai, Asako; Yamamoto, Hiroyuki; Kaji, Hironori; Horii, Fumitaka

doi:10.1016/s0926-2040(03)00013-4

Cited by 38 publications

(42 citation statements)

References 28 publications

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“…Since the reaction proceeds from the surface area of the microfibril towards the inner core under this experimental condition, it should be pointed out that O(6)HU groups are not exclusively located on the surface of the microfibril, but they are also distributed almost at random in the inner region together with O(6)HD groups. This result is in good accord with the previous results obtained by 1 H and 13 C spin diffusion experiments for bacterial cellulose (Masuda et al 2003): the C4D and C4U carbons are also distributed almost at random in the entire region of the microfibrils. Figure 7 shows the nitration of O(6)HD and O(6)HU groups as a function of the reaction time (at the medium concentration of nitric acid) as solid lines.…”

Section: Resultssupporting

confidence: 93%

“…Moreover, the O6...O5 intermolecular and O6...O2 intramolecular hydrogen bondings are mostly formed in the crystalline component, owing to the t-g conformation (Nishiyama et al 2002(Nishiyama et al , 2003, whereas such hydrogen bonds are not allowed to form in the disordered component. In our previous paper (Masuda et al 2003), 1 H and 13 C spin diffusion analyses using the C4D and C4U lines showed that the disordered component is distributed almost at random in the entire region of each microfibril for bacterial cellulose. Nevertheless, more detailed information about the disordered component should also be obtained by using the C6D and C6U lines that are directly associated with the changes in conformation and hydrogen bonding for the CH 2 OH groups.…”

Section: Introductionmentioning

confidence: 87%

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Structural studies of bacterial cellulose through the solid-phase nitration and acetylation by CP/MAS 13C NMR spectroscopy

2006

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The solid-phase nitration and acetylation processes of bacterial cellulose have been investigated mainly by CP/MAS 13 C NMR spectroscopy to clarify the features of these reactions in relation to the characterization of the disordered component included in the microfibrils. CP/MAS 13 C NMR spectra of bacterial and Valonia cellulose samples are markedly changed as the nitration progresses, in a similar way to the case of cotton linters previously reported; and the relative reactivity of the OH groups in the glucose residues is found to decrease in the order of O(6)H>O(2)H>O(3)H. Moreover, the nitration rate and mode greatly depend on the concentration of nitric acid in the reaction media. At dilute and medium concentrations, the O(6)H groups in the crystalline and disordered components are subjected to nitration at nearly the same rate, indicating that these two components are distributed almost at random in the entire region of each microfibril. The preferential penetration of nitric acid into each microfibril also occurs prior to nitration at the medium concentration, resulting in an increase in the mole fraction of the disordered component. In contrast, all OH groups undergo nitration very rapidly at the higher concentration, although nitration levels off to a certain extent for O(3)H groups. In solid-phase acetylation, no regio-selective reactivity is observed among the three kinds of OH groups, which may be due to the characteristic reaction that proceeds in a very thin layer between the acetylated and nonacetylated regions in each microfibril. The almost random distribution of the disordered component in the entire region of the microfibrils is also confirmed in this solid-phase acetylation. On the basis of these results, the mechanism of the solid-phase reactions and the microfibril structure are discussed.

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Section: Resultssupporting

confidence: 93%

Section: Introductionmentioning

confidence: 87%

Structural studies of bacterial cellulose through the solid-phase nitration and acetylation by CP/MAS 13C NMR spectroscopy

2006

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“…0.26 nm. 21 A comparison with the calculated distances from the cellulose crystalline Ia model (Supplementary Figure S2) suggests that the CP curves in Figure 3d are produced by direct-bonded 1 H interaction. By selecting the data for analysis on the basis of the first PCA result, the change in the contact time in the range of 10 to 50 ms, in which energy exchange by direct-bonded 1 H is the main effect, was characterized more clearly in the second PCA.…”

Section: Annotation Of Chemical Shifts Extracted From Pca-loading Plotmentioning

confidence: 95%

Statistical approach for solid-state NMR spectra of cellulose derived from a series of variable parameters

Okushita

Komatsu

Chikayama

et al. 2012

Polym J

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Principle component analysis (PCA) was used to extract components from the solid-state nuclear magnetic resonance (NMR) spectra of bacterial cellulose (BC). Polymers such as cellulose have several domain structures, and their structure and dynamics are reflected in the variety of solid-state spectra derived from different parameters. The complexity of the obtained spectra makes the analysis of spectra from relaxation measurements difficult. Multivariate analysis, such as PCA, has been suggested as an option to improve NMR spectral analyses. In this study, we attempted to extract peak components from cross polarization (CP) experiment data from the variable contact time spectra of BC by using PCA. The extracted peaks were annotated according to previous reports, and the existence of crystalline Ia was clearly recognized. The important components of the BC structure (that is, crystalline Ia, amorphous form and mobility) were separated in the PCA-loading plot and CP curve.

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“…161, 2013 469 to estimate how far apart these domains are. Proton spin-diffusion experiments on this principle have been applied to wood (Newman, 1992;Altaner et al, 2006) and bacterial cellulose (Masuda et al, 2003). A twodimensional (2D) representation of this experiment has been employed (Fernandes et al, 2011) to explore the disposition of ordered and disordered regions in spruce cellulose, making use of differences in their spatial separation from lignin.…”

Section: Proton Spin-diffusion Experiments and Spatial Relationships mentioning

confidence: 99%

Structure of Cellulose Microfibrils in Primary Cell Walls from Collenchyma

et al. 2012

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In the primary walls of growing plant cells, the glucose polymer cellulose is assembled into long microfibrils a few nanometers in diameter. The rigidity and orientation of these microfibrils control cell expansion; therefore, cellulose synthesis is a key factor in the growth and morphogenesis of plants. Celery (Apium graveolens) collenchyma is a useful model system for the study of primary wall microfibril structure because its microfibrils are oriented with unusual uniformity, facilitating spectroscopic and diffraction experiments. Using a combination of x-ray and neutron scattering methods with vibrational and nuclear magnetic resonance spectroscopy, we show that celery collenchyma microfibrils were 2.9 to 3.0 nm in mean diameter, with a most probable structure containing 24 chains in cross section, arranged in eight hydrogen-bonded sheets of three chains, with extensive disorder in lateral packing, conformation, and hydrogen bonding. A similar 18-chain structure, and 24-chain structures of different shape, fitted the data less well. Conformational disorder was largely restricted to the surface chains, but disorder in chain packing was not. That is, in position and orientation, the surface chains conformed to the disordered lattice constituting the core of each microfibril. There was evidence that adjacent microfibrils were noncovalently aggregated together over part of their length, suggesting that the need to disrupt these aggregates might be a constraining factor in growth and in the hydrolysis of cellulose for biofuel production.Growth and form in plants are controlled by the precisely oriented expansion of the walls of individual cells. The driving force for cell expansion is osmotic, but the rate and direction of expansion are controlled by the mechanical properties of the cell wall (Szymanski and

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Solid-state 13C and 1H spin diffusion NMR analyses of the microfibril structure for bacterial cellulose

Cited by 38 publications

References 28 publications

Structural studies of bacterial cellulose through the solid-phase nitration and acetylation by CP/MAS 13C NMR spectroscopy

Structural studies of bacterial cellulose through the solid-phase nitration and acetylation by CP/MAS 13C NMR spectroscopy

Statistical approach for solid-state NMR spectra of cellulose derived from a series of variable parameters

Structure of Cellulose Microfibrils in Primary Cell Walls from Collenchyma

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