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Title: The biochemistry and physiology of digenetic ova and larvae
Author: Wilson, Robert Alan
Awarding Body: University of London
Current Institution: Imperial College London
Date of Award: 1965
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A survey of digene life cycles was undertaken, in order to find a species which would yield sufficient material for a study of egg physiology and biochemistry. Fasciola hepatica was chosen as an experimental animal and a broad but intensive study of the egg was carried out. The general structure of the egg and miracidium was investigated by conventional histological techniques and special emphasis was placed on morphological features having relevance to the experimental work. The structure of the shell and membranes was determined using electron microscopy and chromatographic techniques. The permeability of the shell and membrane system was also investigated by means of simple physical experiments, and by use of radio-tracers. An explanation of the function of the shell, and of the origins and function of the 'vitelline membrane complex' was put forward. The nature and utilisation of food reserves during development was studied by histochemical means and by chemical analysis. The changes in dry weight and respiration of developing eggs were also measured and the underlying biochemistry was discussed. The structure and function of the flame cell system was investigated by studying variations in flame cell activity, and by observing the effect of vital dyes. An interpretation of the function of the system was advanced, based on the experimental results obtained. The hatching mechanism was studied in a variety of experiments, and the chemical properties and fine structure of the viscous cushion were determined. The hatching enzyme theory postulated by Rowan was seriously questioned, and an alternative hypothesis, taking into account the hydro— dynamic properties of the viscous cushion, was put forward. Finally, observations on the factors affecting miracidial behav— iour were recorded and the overall biology of the egg and miracidium was discussed.
Supervisor: Mahon, June ; Call, F. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available