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    Isolation, macromolecular properties, and combining site of a chito-oligosaccharide-specific lectin from the exudate of ridge gourd (Luffa acutangula).
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    Abstract:
    A lectin specific for chito-oligosaccharides from the exudate of ridge gourd (Luffa acutangula) fruits has been purified to homogeneity by affinity chromatography. The lectin has a molecular weight of 48,000, an S(0)20,w of 4.06 S and a Stokes radius of 2.9 nm. Upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis, a single band corresponding to Mr of 24,000 was observed both in the presence and absence of beta-mercaptoethanol. The subunits in this dimeric lectin are, therefore, held together solely by noncovalent interactions. The lectin is not a glycoprotein, and secondary structure analysis by CD measurements showed 31% alpha-helix. The hemagglutinating activity of L. acutangula agglutinin was not inhibited by any of the monosaccharides tested. Among the disaccharides only di-N-acetylchitobiose was inhibitory. The inhibitory potency of chito-oligosaccharides increased dramatically with their size up to penta-N-acetylchitopentaose. The lectin has two binding sites for saccharides. The affinity of chito-oligosaccharides for L. acutangula lectin, as monitored by titrating the changes in the near UV-CD spectra and intrinsic fluorescence, increased strikingly with the number of GlcNAc units in them. The values of delta G, delta H, and delta S for the binding process showed a pronounced dependence on the size of the chito-oligosaccharides, indicating that the binding of higher oligomers is progressively more favored thermodynamically than di-N-acetylchitobiose. The thermodynamic data are consistent with an extended binding site in this lectin, which accommodates a tetrasaccharide.
    Keywords:
    Gourd
    Exudate
    Isolation
    Abstract The ability of corn root exudate to complex metal ions, in particular lead, has been investigated. It was found that exudate solubilizes lead present in different forms in the solid phase. Zn++ was found to compete moderately with Pb++ for exudate ligands while K+, Ca++ and Mg++ showed little competition. The importance of the complexing property of exudate in soil-water-plant relationships is discussed.
    Exudate
    Polarography
    Citations (6)
    When contained within the wound space, exudate performs a valuable role in wound healing. However, managing wounds with high levels of exudate is a commonly cited clinical problem. High levels of exudate cause problems in terms of selecting appropriate dressings and also in preventing potential damage to the surrounding skin caused by contact with exudate.
    Exudate
    Citations (19)
    Wound exudate is all too often perceived as a clinical management problem. While this can be the case, it should be recognized that exudate does fulfil an important function in the healing process. Gradual acceptance of the benefits of moist wound healing, combined with the current goals of the ‘ideal’ moist environment, focuses attention on the role of exudate. This review is intended to define the components and functions of ‘normal’ exudate and differentiate it from abnormal exudate.
    Exudate
    Exudate
    Epidermis (zoology)
    Cuticle (hair)
    Petunia
    Plant cuticle
    Citations (29)
    Abstract Seeds of mahoe exude a brown watersoluble substance over a number of days. The properties of this exudate were examined. Mahoe seed did not germinate until all exudate was removed. Extracts of exudate inhibited germination of leached mahoe seed and five of six other species tested. Replacement of the exudate with fresh water restored germination in mahoe and in all but one test species. It is concluded that the exudate acts mainly as an autoinhibitor and has little allelopathic role. It confers an advantage on mahoe seedling establishment by allowing germination only after long periods of rain.
    Exudate
    Allelopathy
    This paper describes the presence and amounts of free glucose, hexosamine and hexuronic acid in the gingival exudate. Exudate was sampled on filterstrips from individuals with different degrees of gingival inflammation. The strips were weighed before and after absorption of exudate and the exudate was calculated. The exudate was extracted and the content of glucose, hexosamine and hexuronic acid was determined colorimetrically. In keeping with previous studies the amount of exudate increased with the severity of inflammation. Exudate glucose varied between 1.13 and 7.09 μg/mg exudate. The hexosamine content was approximately 0.6 μg/mg and the hexuronic acid concentration varied between 50 and 60 μg/mg. The possible sources of origin of the carbohydrate components are discussed.
    Exudate
    Carbohydrate Metabolism