Hobot, Jan Adam (1977) Spore germination in the fungus Syncephalastrum racemosum. Doctor of Philosophy (PhD) thesis, University of Kent. (doi:10.22024/UniKent/01.02.94418) (KAR id:94418)
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Official URL: https://doi.org/10.22024/UniKent/01.02.94418 |
Abstract
The asexual part of the life cycle of the fungus Syncephalastrum racemosum was investigated using light microscopy, transmission and scanning electron microscopy. The structure and organisation of the vegetative mycelium and spore producing hyphae was studied in detail. Freeze-fracturing, surface replica, metal shadowing and thin sectioning techniques were used to investigate the ultrastrueture of dormant and germinated spore walls subjected to various sequential chemical treatments. The spore wall had a highly complex organisation, consisting of four, major ultrastructurally definable layers. (1) A surface layer consisting of a cross-patched network of rodlets, having a 25nm periodicity. (2) A plate-like layer covered by amorphous material.(3) A layer of thick 17»5nm diameter microfibrils. (4) An innermost layer of thin 8nm diameter microfibrils. The emergent germ tube has a smooth outer surface and an inner layer of thin microfibrils. The breakpoint between spore and germ tube is clearly delimited at various levels within the spore wall. Tentative identification of the wall layers showed: (1) the rodlet layer was mainly protein; (2) the thick microfibrils were probably a β-glucan; (3) the thin microfibrils were chitin. Freeze-fracturing of dormant and germinated spores revealed differences in plasmamembrane ultrastructure. Large particles (34nm) with complimentary large depressions (33nm) were present only in fractures of the plasmamembrane of dormant spores. During germination there is an increase in the numbers of small particles (8.4nm) in the membrane. The physiology of spore germination was studied in shake-flask and batch fermenter cultures. In the presence of glucose, spore swelling preceded outgrowth of germ tubes. Glucose was essential for initiation of these events. Swelling ceased quickly when glucose was removed. Analysis of size distributions within spore populations indicated that the larger spores germinated first. A self-inhibitor of germination was extracted from culture and spore washings, and was identified as nonanoic acid.
Item Type: | Thesis (Doctor of Philosophy (PhD)) |
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Thesis advisor: | Gull, Keith |
DOI/Identification number: | 10.22024/UniKent/01.02.94418 |
Additional information: | This thesis has been digitised by EThOS, the British Library digitisation service, for purposes of preservation and dissemination. It was uploaded to KAR on 25 April 2022 in order to hold its content and record within University of Kent systems. It is available Open Access using a Creative Commons Attribution, Non-commercial, No Derivatives (https://creativecommons.org/licenses/by-nc-nd/4.0/) licence so that the thesis and its author, can benefit from opportunities for increased readership and citation. This was done in line with University of Kent policies (https://www.kent.ac.uk/is/strategy/docs/Kent%20Open%20Access%20policy.pdf). If you feel that your rights are compromised by open access to this thesis, or if you would like more information about its availability, please contact us at ResearchSupport@kent.ac.uk and we will seriously consider your claim under the terms of our Take-Down Policy (https://www.kent.ac.uk/is/regulations/library/kar-take-down-policy.html). |
Subjects: | Q Science |
Divisions: | Divisions > Division of Natural Sciences > Biosciences |
SWORD Depositor: | SWORD Copy |
Depositing User: | SWORD Copy |
Date Deposited: | 26 Aug 2022 15:38 UTC |
Last Modified: | 26 Aug 2022 15:49 UTC |
Resource URI: | https://kar.kent.ac.uk/id/eprint/94418 (The current URI for this page, for reference purposes) |
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