Tobacco cell-wall studies

In tobacco primary cell wall the cellulose microfibrils observed individually or associated with bundles were also triple-stranded and left-hand helical. These observations are shown in Figure 10. Since cellulose is only 19% of the tobacco cell wall (17), the task of finding and identifying cellulose was complicated. For this reason A. xylinum which produces a pure ribbon of cellulose was used for studying cellulose structure. 

In 1977, Ohnishi and Kato (2850) described the identification of several carbonyl compounds in the pyrolysates from the tobacco cell-wall polysaccharides cellulose, hemicellu-lose, and pectins. They noted that these biopolymeric polysaccharides constituted 30% to 50% of the dry weight of the tobacco they were studying. Sakuma et al. pyrolyzed tobacco-derived cellulose (3401), chlorogenic acid, and rutin (3400) and reported various aldehydes and ketones plus numerous phenols in the pyrolysates. Many of the pyrolysate components identified have also been identified in cigarette MSS. 

F.W. Best Isotopic fate studies with tobacco constituents. in. Cell-wall constituents. A. Pectic substances RDM, 1967, No. 42, August 10, see www.ijrtdocs.com 500613423 -3437 Isotopic fate studies with tobacco con-stiments. IV. Starch RDM, 1970, No. 109, December 9, see www.ijrtdocs.com 500615233 -5254 Isotopic fate studies with tobacco constiments. III. Cell-wall constituents. B. a-Cellulose RDM, 1971, No. 14, March 16, see... 

Further support for cell wall biosynthesis as a target site was provided by Umetsu et al, who reported abnormal swelling of cultured soybean cells treated with dichlobenil. Dichlobenil was also shown to be an effective and reversible inhibitor of cell wall formation in tobacco protoplasts. It was considerably more potent than other cell wall inhibitors, such as coumarin, and it caused the formation of multinucleate protoplasts. Inhibition of cellulose biosynthesis prevented cell wall formation and cytokinesis but nuclear division that is, mitosis was unaffected. Further studies with tobacco protoplasts confirmed the specific and potent inhibition associated with the cellulose-synthesizing complex at the plasma membrane. 

Methylation analysis of the tetra-arabinosides isolated from primary cell walls of tomato and sycamore indicates that the arabinosyl residues are terminal and 2- and 3-linked (71, 123). Akiyama and Kato (2) have studied the hydroxyproline arabinosides obtained from suspension-cultured cells of tobacco (Nicotiana tabacum). These workers used periodate oxidation (Smith degradation), methylation analyses, NMR, and optical rotation to show that the structure of the hydroxyproline tetra-arabinoside is Araf-(1 3)-Araf-(l - 2)-Arar(l - 2)-Arar(l - 4)-hydroxyproline. 

Proc Okla Acad Sci 1974 54 34-35. Demole, E., and C. Demole. A chemical study of hurley tobacco flavour Nicotiarui tabacum). VII. Identification and synthesis of twelve irregular terpenoids related to solanone, including 7,8-dioxabicycIo[3,2,l]-octane and 4,9-dioxabicycIo[3.3.1 Jnonane derivatives. Helv Chim Acta 1975 58 1867. Bharadwaj, B. V., S. Takayama, T. Yamada, and A. Tanimura. N -nitro-sonornicotine in Japanese tobacco products. Gann 1975 66 585. Randolph, H. R. Gas chromatographic determination of nicotine in an isopropyl alcohol extract of smoke particulate matter. Tobacco 1974 176 44-Yung, K. H., and D. H. Northcote. Enzymes in the walls of mesophyll cells of tobacco leaves. Biochem J 1975 151 141. 

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