Thesis (Ph. D.)--Institute of Paper Chemistry, 1976. / Bibliography: leaves 106-110.

The focus of this thesis is to examine the structural properties of polysaccharides produced by bacteria, as well as the dynamic and conformational behavior of a synthetically derived oligosaccharide. The primary structures of the O-polysaccharide repeating units of four different Escherichia coli (E. coli) strains, namely O175, O177, O103 and TD2158, as well as the first report of a capsular polysaccharide produced by lactic acid bacteria Leuconostoc mesenteroides ssp. cremoris PIA2 are reported in paper I–V. Structural analyses have been performed using a combination of nuclear magnetic resonance spectroscopy and chemical component analysis. The elucidated structures in paper I–III, as well as paper V, are composed of linear repeating units of varying composition and length. In paper IV, the structure of the O-polysaccharide repeating unit of E. coli TD2158 is determined to be a branched hexasaccharide structure with a heterogeneous substitution pattern, with either a β-GlcpNAc or β-Glcp residue branching to the backbone chain. Incubation with bacteriophage HK620 tailspike protein shows that the polysaccharide is selectively cleaved at the α-GlcpNAc-(1→2)-α-Rhap-linkage of the backbone chain, yielding a 9:1 ratio of β-GlcpNAc/β-Glcp containing hexasaccharides after digestion. In paper VI the conformational properties of a trisaccharide, which constitutes an internal epitope of the LeaLex hexasaccharide over-expressed on the surface of squamous lung cancer cells, have been analyzed using NMR spectroscopy and molecular dynamics simulations. The β-(1→3)-linkage of the trisaccharide was shown to be highly flexible. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Submitted. Paper 6: Submitted.</p>

Cell wall loosening and degradation are important processes in major stages of plant development including fruit ripening. Three main mechanisms have been proposed to contribute towards cell wall polysaccharide degradation in vivo: enzymic hydrolysis by endopolygalacturonase (EPG), enzymic elimination by pectate lyase (PL), and non-enzymic scission by hydroxyl radicals (•OH). However, little idea as to which of these three mechanisms predominates in homogalacturonan degradation especially during fruit ripening. This study presents an attempt to discover the respective contribution of those three mechanisms of attack. The strategy used to achieve the objective of this study was to identify and measure homogalacturonan molecules that exhibit symptoms of each mechanism of attack. A method that was developed in this study is a fluorescent labelling method mainly to study the •OH attack on pectic polysaccharides. This labelling method is based on the ability of 2-aminoacridone (2-AMAC) to reductively aminate oxo groups of sugar moieties followed by exhaustive digestion with Driselase. In a model in-vitro experiment, the developed novel fluorescent labelling method, when applied to homogalacturonan, that had been attacked by •OH (Fenton reagent), produced at least three fluorescent ‘fingerprint’ compounds, separable by high-voltage paper electrophoresis (HVPE) based on their charge/mass properties at pH 6.5 and also by high pressure liquid chromatography (HPLC) on a C18 column with a fluorescence detector at λem= 520 nm. These fingerprint compounds include: a monomer, 1A*; a dimer, 2A*; and an unidentified compound, X*. In-vivo application with alcoholinsoluble residue (AIR) of seven species of fruit (pear, mango, banana, apple, avocado, strawberry and strawberry tree fruit) at three stages of softening produced at least two fluorescent fingerprint compounds: a monomer, 1AF and a dimer, 2AF. XF, an interesting compound found in a few samples in in-vivo experiments, showed electrophoretic mobility similar to X*; however, the retention time of this compound on HPLC did not agree with that of X*. 2AF was suggested to be exclusive evidence for •OH attack in vivo while 1AF was suggested to be a useful evidence not only to reveal •OH attack but also to reveal EPG and PL attack on pectic polysaccharides during fruit softening. HVPE and HPLC results showed an increasing pattern of 2AF in mango, banana, avocado and strawberry tree fruit, which indicated progressive •OH attack on pectic polysaccharides during the softening process. There was no clear evidence of 2AF at any stage of softening in apple and strawberry, which may suggest that fruit softening in apple and strawberry was not associated with •OH attack. On the other hand, HVPE analysis of 1AF showed and increasing pattern in pear, mango, banana, avocado and strawberry tree fruit, which may indicate EPG, PL and/or •OH attack during fruit softening. Production of these fluorescent fingerprint compounds provides good evidence for •OH attack on pectic polysaccharides, and has the potential to give useful information for EPG and PL attack in vivo.

Thesis (Ph.D.)--McMaster University (Canada), 1992. / Source: Dissertation Abstracts International, Volume: 54-08, Section: B, page: 4119. Adviser: D. B. MacLean.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2002. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 4 uppsatser.

Thesis (M. Phil.)--University of Hong Kong, 2010. / Includes bibliographical references (leaves 139-161). Also available in print.

Thesis (M. Med. Sc.)--University of Hong Kong, 2005.

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