Isolation and chemical characterization of Yariv beta-glucosyl reagent: Positive macromolecules released by Gymnocolea inflata when leaf and branch development are desuppressed.
Item
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Title
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Isolation and chemical characterization of Yariv beta-glucosyl reagent: Positive macromolecules released by Gymnocolea inflata when leaf and branch development are desuppressed.
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Identifier
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AAI9959223
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identifier
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9959223
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Creator
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Salama, Nahed.
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Contributor
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Adviser: Dominick V. Basile
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Date
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2000
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biology, Botany
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Abstract
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The presence of ammonium ion in the nutrient medium of axenically cultured plants of Gymnocolea inflata (Huds.) Dum. resulted in desuppressed cell proliferation in otherwise suppressed leaf and branch primordia. Antagonists of hydroxyproline-protein synthesis had produced these changes in the pattern of cell proliferation in relation to leaf and branch development earlier in four other species of leafy liverworts.;Since molecules released into the culture medium correlated with both ion- and antagonist-induced desuppression were stained by Yariv beta-glucosyl reagent, a reagent diagnostic of arabinogalactan-proteins (AGPs), it was hypothesized that there was a causal relationship between the release of AGPs and desuppressed leaf and branch development. Because Yariv beta-glucosyl reagent sometimes binds to macromolecules lacking an hydroxyproline-protein component, it was deemed necessary to chemically characterize the Yariv reagent-positive molecules as a test of this hypothesis.;Two monoclonal antibodies (McAbs) developed against Yariv reagent-positive molecules released by desuppressed G. inflata plants were used to affinity purify the molecules they specified away from other components of their culture medium. The affinity purified molecules were subjected to SDS-PAGE, amino acid, as well as carbohydrate composition and linkage analysis.;The results of all the analyses showed the Yariv reagent-positive molecules specified by the McAbs to be bona fide hydroxyproline-containing AGPs. The amino acid composition of the protein moieties of the AGPs released correlated with desuppressed development was distinctly different from those released or extractable from plants with normally suppressed leaf and branch development. This finding is interpreted to mean that it was the altered composition of the AGPs that resulted in their function being impaired.;By extrapolation, the results of this investigation support two related hypotheses. The first is that the Yariv beta-glucosyl reagent-positive molecules released when suppressed leaf and branch development in G. inflata and other liverworts are desuppressed AGPs. The second is that certain AGPs play a pivotal role in determining where and when during the course of plant development cell proliferation is suppressed or desuppressed.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
