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Yamashita, Daichi,Kimura, Satoshi,Wada, Masahisa,Takabe, Keiji Springer-Verlag 2016 Journal of wood science Vol.62 No.2
<P>The traditional Maule color reaction was improved by use of tris(hydroxymethyl) aminomethane-hydrochloride acid (Tris-HCl) buffer coupled with a fluorescence microscope. The purple-red color of Maule-treated hardwood was more stable with the novel treatment than with traditional treatment. In addition, Maule-treated wood samples had a characteristic fluorescence when excited with blue (460-495 nm) light. Examination of white birch (Betula platyphylla) showed that syringyl-rich and guaiacyl-rich cell walls emitted red and yellow fluorescence, respectively. Measuring the fluorescence spectra of hardwood and softwood powders after treatment with the new Maule reagents showed that hardwood powder containing syringyl lignin emitted a red fluorescence, whereas softwood powder containing guaiacyl lignin emitted a green fluorescence when excited with blue light. In conclusion, this improved technique has many advantages compared with the traditional Maule color test.</P>
Jong Sik Kim,Tatsuya Awano,Arata Yoshinaga,Keiji Takabe 한국목재공학회 2011 목재공학 Vol.39 No.5
The distribution of arabino-4-O-methylglucuronoxylans (AGXs) and O-acetyl-galactoglucomamians (GGMs) in warts and the warty layer of tracheids in normal wood (NW) and compression wood (CW) of Cryptomeria japonica was investigated. Under field emission scanning electron microscope (FE-SEM) observation, warts and the warty layer of delignified NW and CW tracheids were degraded by xylanase treatment, indicating that warts and the warty layer contain high amounts of AGXs. However, the effect of xylanase was not observed in NW and CW tracheids before delignification, suggesting that AGXs in warts and the warty layer may be encrusted with lignin. After β-mannanase treatment, no noticeable changes were observed in warts and the warty layer of NW tracheids, indicating that warts and the warty layer contain either no or very few GGMs. Similar results to FE-SEM observations were also observed with immunogold labeling. AGX labeling was observed in warts and the warty layer of NW and CW tracheids, while GGM labeling was not detected. NW tracheids showed a much stronger density of AGX labeling than did CW tracheids in warts and the warty layer, indicating differences in the chemical compositions of warts and the warty layer between NW and CW tracheids.
Effect of ammonia treatment on white birch wood
Yamashita, Daichi,Kimura, Satoshi,Wada, Masahisa,Samejima, Masahiro,Takabe, Keiji Walter de Gruyter und Co 2018 Holzforschung Vol.72 No.1
<P><B>Abstract</B></P><P>Transverse sections of white birch (<I>Betula platyphylla</I>) were treated with anhydrous ammonia at 60-140°C (ammonia treatment, AT). As a result, the crystal structure of cellulose in the AT samples changed to cellulose III<SUB>I</SUB>, and acetamide was produced. The surface area of the AT samples, the amount of sugar released upon acid hydrolysis and the lignin content were not changed. However, a small amount of lignin became acid soluble. Mäule color reaction, indicative of the presence of syringyl lignin, showed decreasing color intensities with increasing temperature of AT. The results can be easily interpreted that AT affects ester linkages and side chains of hemicelluloses and syringyl lignin. In addition, AT was carried out on 1-μm thick transverse sections and block specimens. Xylanase treatment and immunolabeling revealed that AT enhances xylan degradation, but ray cells are resistant to xylanase even after AT. On the block sample, a deposited xylan layer appeared on the inner surface of fiber cell walls. Apparently, xylan moved to the surface in contact with the fluid ammonia during AT. The vessel cell wall did not show a similar migration effect, indicating a cell wall-specific interaction with ammonia.</P>