http://hdl.handle.net/1893/2675 Electronic theses from legacy departments related to the Faculty of Natural Sciences 2026-10-03T04:21:30Z http://hdl.handle.net/1893/35147 Title: Deamination and related reactions of some bicyclo-octylamines Author(s): Wilson, Alan A Abstract: The bicyclo-octylamines (1-5) have been deaminated by the nitrous acid method and by the decomposition of their nitrosocarbamates in ethanol. In addition, the amines (1-4) were deaminated by the decomposition of their triazenes in acetic acid. Complete quantitative analyses of the products [diagrams displayed] from the nitrosocarbamate decompositions were obtained using analytical capillary column g.l.c. techniques developed by Banks1. Incomplete information was obtained from the nitrous acid and triazene decompositions. The results from (1) and (2) were very different from the solvolysis products of the corresponding tosylates reported earlier by Banks1 but broadly in agreement with the results from cis- and trans-4-t-butylcyclohexylamines. The endo-amine (1) gave large amounts of elimination and hydride shift products. At the unrearranged position, internal substitution to give R-X (Scheme) occurred with predominant retention of configuration. Unrearranged external substitution product, R-Y, was mainly of inverted configuration. The exo-amine (2) gave less elimination and [equation displayed], and hydrocarbon rearrangement. Both internal and external substitution occurred with predominant retention of configuration at the unrearranged position. There was some evidence that this amine reacted, to a small extent, through a non-chair conformer. The model proposed by Maskill and Whiting involving an ion pair separated by molecular nitrogen was used, with minor alterations, to accommodate these results. The products of deamination of amines (3) and (4) were similar but not identical and included large amounts of hydrocarbon and products derived from carbon migration. However, both amines showed a tendency to maintain their structural identity when compared with the products of solvolysis of the 3 corresponding tosylates. The results suggest initial formation of the classical carbonium ions (6) and (7) from (3) and (4) respectively followed by relaxation to a common non-classical ion (8). [diagrams displayed] Deamination of (5) gave a very different distribution of products from (3) and (4). Very little rearranged product was observed and most of the substitution was with retention of configuration although a small but significant amount was inverted, Initial formation of a classical carbonium ion, with nominal structure (6), followed by relaxation to the non-classical ion (9) is proposed as a possible mechanism. The different fates [diagram displayed] of the initially formed carbonium ions from (5) and (3) are thought to be due to the different positions of the counter-ions. The mode of decomposition of adamant-2-yl-0NN-azoxy-tosylate (10) has been investigated as a link between deamination and tosylate solvolysis which would be amenable to kinetic studies. Preliminary results suggested that the mechanism is ionic, the activated complex having carbonium ion character. Isolation of 2-adamantyl tosylate from the ethanolysis of (10) is presented as evidence for internal return of tosylate anion in solvolysis of alkyl tosylates. [diagram displayed] 1979-01-01T00:00:00Z http://hdl.handle.net/1893/35145 Title: The breeding biology of Euchaeta norvegica (Copepoda : Calanoida) Author(s): Hopkins, C C E Abstract: First few paragraphs from General Introduction GENERAL INTRODUCTION OBJECTIVES: Euchaeta norvegica (Boeck, 1872) is one of the larger species of calanoid copepod (adult females = 7-llmm total length, adult males 5.5-7mm total length) and has a widespread distribution in northern waters. Details of its distribution provided from the records of the Continuous Plankton Recorder Survey (Edinburgh Oceanographic Laboratory, 1973) show that it is present throughout the northern temperate waters of the north Atlantic Ocean, with its centre of abundance situated in the boreal waters of the Greenland-Labrador Current Complex. Hedgpeth (1957), in his classification of marine environments, showed the boundary between oceanic and neritic as approximating to the position of the 100-fathom (ca.182 metre) depth contour. Colebrook (1964, 1972) has since found that further divisions in the classification of geographic areas and water types are possible and has classified E. norvegica as being a typical component of the "north-west oceanic" plankton community. Relatively few specimens of E. norvegica are found in neritic seas although it is often found in abundance in Norwegian fjords and Scottish west coast sea lochs, and the deep waters associated with them. In its typical oceanic environment the adults occupy an essentially mesopelagic depth distribution whilst the younger copepodite stages are found in the more surface waters. A large body size and its often high abundance makes E. norve£ica one of the dominant biomass copepods of the northern temperate and boreal plankton communities. This, coupled with the fact that it appears to be wholly carnivorous (see Harding, 1974), emphasises the importance of this copepod in marine ecosystems. It is thus surprising that little published information is available about the biology and ecology of this species. The necessity to mate and breed is a dominant factor in an animal's life. The research presented in this thesis was carried out in order to examine these important processes in E. norvegica with particular reference to those aspects which are likely to determine the breeding intensity of a population. This study has, therefore, concentrated on an examination of sperm and spermatophore production in relation to fertilization and subsequent egg-laying, rather than the development of generation cycles after the eggs have hatched. The female reproductive system has been described, with an emphasis on its function during mating and egg-laying. The male reproductive system has been described and its histology and ultrastructure have been investigated with regard to secretion of the various components of the spermatophore. The mating process and the inseminatory position adopted by the male has been predicted. Analyses have been made of the frequency distributions of spermatophores found on adult females as well as the patterns of distribution of these spermatophores on the different areas of the female genital segment. The significance of such distributions have been discussed in terms of mating behaviour. The relationship between maternal body size and the size of the egg- clutch produced has been quantified. Seasonal variations in the sex- ratio of adults, as well as stage IV and stage V copepodites, have been followed and possible factors responsible for these changes have been discussed. Finally, the proportion of males present in the adult population has been examined as a factor determining the numbers of spermatophores attached to adult females and the quantity of egg-sacs subsequently produced by the population. 1976-01-01T00:00:00Z http://hdl.handle.net/1893/35144 Title: The metabolism of Carbon dioxide in maize leaf epidermis Author(s): Breeze, M J Abstract: Though the maize leaf has a large proportion (more than 30%) of its volume occupied by largely non-photosynthetic (yet probably respiring) epidermal tissue it has been reported that no carbon dioxide (CO2) escapes from it in the light, even into a CO2 -free air stream. The aim of this investigation was to determine if the epidermis was active and if it was to discover the fate of the CO2 produced in it by respiration. Light and electron microscopy revealed that all epidermal cells had an apparently viable cytoplasm containing a full complement of organelles. The long epidermal cells, despite their large size, contained less cytoplasm than the cells of the stomata, an arrangement suggesting an uneven distribution of respiratory activity. Respirometry, despite considerable problems involved in the isolation of viable tissue, tended to confirm this view. Appreciable respiration was recorded in preparations containing only active stomatal cells and little or no increase in respiratory gas exchange could be detected in epidermal strips having a larger proportion of intact cells. Respiration was apparently unaffected by light. Since CO2 was released front isolated epidermal tissue in both the light and dark it was thought necessary to investigate potential mechanisms by which it could be retained in the light. A number of carboxylating and associated enzymes were assayed in extracts prepared from the lower epidermis of maize leaves. Evidence for appreciable activities of both phosphoenolpyruvate (PEP) carboxylase and malic enzyme were obtained, both were localised in the stomata. Some evidence for the presence of ribulosebisphosphate (RuBP) carboxylase in long epidermal cells was also found, though it was felt to be too circumstantial for a definite conclusion to be reached. The cuticular resistance to water vapour loss indicated that the resistance to CO2 escape was probably very high. However, whilst a high cuticular resistance would reduce direct CO2 escape it would also increase the potential advantage to the leaf of preventing the release of gaseous CO2 within it. Overall it was felt that though there was no single mechanism for the retention of CO2 in the epidermis of maize several factors acting together reduced its release to a level undetectable by the techniques used up to now. These factors included a reduced respiration rate in long epidermal cells, a bunching of mesophyll chloroplasts close to the epidermal cells and an appreciable carboxylase activity in the active stomatal cells. 1977-01-01T00:00:00Z http://hdl.handle.net/1893/35143 Title: The digestive physiology and food requirements of Gammarus pulex (L) (Amphipoda) Author(s): Monk, David Charles Abstract: Several freshwater invertebrates, including Gammarus pulex (L), were shown to possess gut cellulase activity. The nutritive physiology of G. pulex was further investigated in order to elucidate the manner in which plant detritus Is utilised as food. This was approached by studying physical and chemical conditions in the gut and the effects of test diets on ingestion, assimilation and digestive enzyme secretion. The extents to which some of these diets and others supported growth and survival were also examined. The results of an investigation into the digestion of decomposing leaf litter and fine detritus by commercial enzymes are described. Cellulase activity in the midgut glands was endogenous. The pH of the midgut gland fluid was little affe3cted by diet and, along with that of the foregut, was well suited to carbohydrate digestion. The pH at the posterior end of the midgut was better suited to protein digestion. The tract transit time was normally independent of the rate of ingestion. Intact plant cells that were not broken open mechanically were not digested chemically in the gut. The occurrence of enzyme inhibitors in leaf litter was investigated. The assimilation efficiency and rates of ingestion and enzyme secretion varied with different diets, but were not correlated with the nutritive values of the diets. Palatability and physical ease of ingestion controlled rates of ingestion and, probably, enzyme secretion. The assimilation efficiency seemed to depend on the surface area of the gut contents available for enzymic attack. Growth and survival were affected by the water chemistry and the initial size of the animals used, as well as by the nature of the diet. Fine particulate detritus was of little nutritive value and the nutritive value of intact elm litter depended on the amount of microbial growth which it supported. Food nutritive value was not directly related to protein content, although the microbial flora was important in furnishing nitrogen requirements, at least during certain critical phases of growth. An energy budget was calculated and food utilisation in G.pulex and other aquatic invertebrates discussed. 1975-01-01T00:00:00Z