14,550 results for Doctoral

  • The complexing of calcium and magnesium by organic plant constituents : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy, Chemistry/Biochemistry Department, Massey University

    Molloy, Leslie Francis (1971)

    Doctoral thesis
    Massey University

    The definition, occurrence and aetiology of hypomagnesaemic tetany is discussed as an introduction to the practical implications of the present investigation. The current hypotheses, involving an unfavourable pasture chemical composition, accounting for the binding of Ca++ and Mg++ in the intestinal tract of ruminants are reviewed. The role of undigested or partly-digested plant cell wall materials is advanced as another such hypothesis, and the present investigation of the cell wall polymers of a typical pasture grass is outlined. The comprehensive analysis of the grass Yorkshire fog (Holcus lanatus) involves, initially, the extraction and purification of pectic substances, lignin, hemicelluloses and cellulose. The non-volatile organic acid content of the grass is also determined. Analytical methods are developed and evaluated in order to assess the homogeneity of these isolated cell wall fractions, and their chemical constitution investigated to aid in determining any possible relationship between cation complexing and polymer (or monomer) structure. The pectic fraction isolated from Yorkshire fog is approximately 90% polygalacturonic acid while the hemicelluloses are basically arabinoxylans with varying hexose and uronic acid content. Attempts tofractionate the predominant hemicellulose, hemicellulose B, into homogenous arabinoxylans gives inconclusive results. Most of the chemical evidence, however, indicates the presence of three discreet polysaccharides in this fraction - a simple arabinoxylan, an acidic galactoarabinoxylan and a neutral glucan. Infrared and ultraviolet spectroscopy is utilised to determine the purity of the isolated lignin as well as the presence of typical lignin functional groups. Yorkshire fog lignin has a moderate phenolic hydroxyl and -OMe content and, like most other monocotyledonous lignins, gives yields of syringaldehyde, vanillin and p-hydroxybenzaldehyde on alkaline nitrobenzene oxidation. The outstanding feature of the lignin is its appreciable content of etherified hydroxyl groups in the 4-position of the aromatic ring and the low yield of syringaldehyde. The water-soluble, non-volatile organic acids are quantitatively determined by anion-exchange resin chromatography and their identity confirmed by paper chromatography. The major acid is the tricarboxylic acid, trans-aconitic acid, which is determined spectrophotometrically. The normal plant acids, citric and malic, are present in moderate quantities while the alicyclic acids, quinic anc shikimic, are only present in minor amounts. A limited amount of data on the seasonal fluctuation of these organic fractions in Yorkshire fog is presented. Electrolytes and the concept of ionic activity are discussed in the introduction to the study of the ability of these plant fractions to bind Ca++ and Mg++ in an aqueous salt solution of cationic composition similar to that of the intestine of a ruminant. A cation exchange method is developed whereby changes in the activity of Ca++ or Mg++ on the introduction of a plant fraction into the salt solution are reflected in the cationic composition of the equilibrium resin. An investigation is undertaken of a large number of calibration solutions varying in [ca++] and[Mg++], but constant in [Na+], [K+] and [NH4+], the latter cations being present in excess as 'swamping' cations. Regression expressions relating solution cation concentration to the equilibrium resin cation concentrations are derived and used as calibration equations to determine the amounts of bound and ionic Ca++ and Mg++ in solutions in equilibrium with the plant fractions. The pectic substances, lignin and the organic acids are effective in complexing a large proportion of the solution Ca in a non-ionic form but only lignin and the organic acids display a significant complexing of solution Mg++. Except for hemicellulose B (branched) at a slightly alkaline pH, the hemicelluloses and cellulose have little ability to complex either Ca++ or Mg++. The complexing results are discussed in terms of the relationship of polymer structure to observed cation affinity. Factors involved in cation binding are: - the charge and degree of hydration of the cation itself; - distribution and degree of esterification of carboxyl groups in the polymer; - monomer conformation; - type of glycosidic linkage in the polymer; - the possibility of hydrogen-bonding and non-bonded interactions between substituents on the polymers; - solution pH. The in vivo implications of the results are finally discussed in the context of general ruminant nutrition and alkaline-earth metal absorption discussed in the introduction.

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  • The kinetics of mild acid hydrolysis of gluten and the functional properties of the modified proteins at various levels of hydrolysis : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Biotechnology at Massey University

    Higgins, John Joseph (1988)

    Doctoral thesis
    Massey University

    Gluten is the mixture of proteins remaining in wheat flour after starch and water soluble components have been extracted by washing. Its unique dough forming properties are due to the structure of the proteins. A feature of the protein is the high glutamine content, about 30% of the total amino acids. A number of studies have shown that gluten's properties of insolubility and water-binding can be substantially modified by mild acid hydrolysis. The principal effect of the mild acid treatment is to hydrolyse the amide side chain of glutamine such that the amide group is replaced by a carboxyl group. In addition, it is known that hydrolysis of peptide bonds can have a large influence on the functional properties of proteins. The aims of this study were to determine the kinetics of the acid catalysed deamidation and peptide bond hydrolysis reactions, and to comment on the resultant changes in functional properties. A statistically designed experiment was used to determine the effect of temperature, hydrogen ion concentration and gluten concentration. An initial rate analysis of the results showed that reactions could be described by equations of the form: Rate of amide bond hydrolysis = k1.[Amide][H+] and Rate of peptide bond hydrolysis = k2 [Peptide] [H+] where k = koe -E/R.1/T A stoichiometric analysis of the experimental data confirmed that hydrogen ions were consumed in both reactions. A numerical solution was developed to predict the extent of reaction with time. A computer program incorporating the solution was used to simulate the reaction and test the solution. The simulation results appeared to overestimate the progress of the reaction with time. A series of ten gluten powders, hydrolysed to different extents was prepared at small pilot scale. The composition of the samples was determined and compared with the extent of hydrolysis predicted by the reaction simulation. Reasonable agreement was achieved. A selection of the functional properties of the prepared samples was examined. The quantity of alkali required to dissolve each preparation to the extent of its solubility at pH 7.6 increased markedly with the extent of hydrolysis due to the additional carboxyl groups requiring neutralization. The flavour of each preparation was exanined. A cereal flavour was found to decrease with the extent of hydrolysis. A lingering bitter flavour was found to increase with the extent of hydrolysis. The solubility of all preparations at p H 7.6 in 0.1 M phosphate buffer increased with the extent of treatment so that the most hydrolysed samples were almost completely soluble. No (significant) difference was found between freeze dried and spray dried samples. Samples prepared without dialysis showed no solubility difference from those prepared with dialysis at a similar extent of hydrolysis. The hydrophobicity of the preparations was measured using two different fluorescent probes and was found to increase with the extent of hydrolysis. The emulsion-forming properties of the preparations were found to depend on the oil used in the test, as would be expected if hydrophobicity was equivalent to the hydrophile lipophile balance, which is commonly used to classify emulsifying agents. The preparations did not, however, show the additivity properties of emulsifiers. It was also shown that only the soluble portion of the preparations was responsible for emulsion formation. The possibility of achieving deamidation of gluten using the enzymes peptidoglutaminase I and II was examined. No activity against gluten or partially hydrolysed gluten was found.

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  • A comparison of the fate of elemental sulphur and sulphate sulphur based fertilizers in pasture soils : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Soil Science at Massey University

    Phimsarn, Sathien (1991)

    Doctoral thesis
    Massey University

    Nitrogen fixation by legumes has a particular requirement for adequate soil sulphur status. Sulphur (S) is a mobile nutrient and is easily leached from aquic soil environments, therefore regular topdressing with S fertilizer is required to maintain legume vigor and pasture production in most New Zealand pasture soils. Escalating fertilizer costs have focused attention on the efficiency of use of S fertilizers, particularly superphosphate (SSP) and alternative elemental S (S0) based fertilizers less liable to leaching loss in this aquic environment. Field and glasshouse trials, using the resident clover/ryegrass sward on undisturbed soil cores (150 mm diameter, 100 mm depth) , were undertaken to determine the comparative short-term fate of SSP and different particle sizes of S0. Methods for manufacturing radioactively labelled (35s) fertilizers were developed. In addition, the effect of sheep dung on the short-term immobilization of soil and fertilizer S was also investigated. A simple computer simulation model explaining the observed transformation of soil sulphur and 35s labelled fertilizer was developed. Initially, the effect of sheep dung on the short-term immobilization of soil and fertilizer S was investigated. Very small amounts (about 2-5%) of plant (clover/ryegrass pasture) S and P, within 1 00 mm of the area surrounding the dung pellet, were derived from the dung. Under the experimental conditions that prevailed, dung S behaved as a slow release S form causing neither greater immobilization of soil or fertilizer S nor mineralization of soil organic S. It was concluded that the impact of dung return on short-term (< one year) S fertilizer fate need not be considered. An initial field trial comparing the fate of microfine S0 (< 0.010 mm) relative to sulphate-based SSP was undertaken on Tokomaru silt loam, a New Zealand yellow-grey earth (Fragiaqualf). The microfine S0 oxidized within 30 days of application but initially (up to 60 days) was slightly less effective than SSP in terms of plant uptake. Over longer periods of time (150 days) their performances were comparable. Final cumulative plant uptake at 150 days accounted for 13.6% of microfine S0 and 16.3% of the SSP-sulphate. The major transformation of 35s from microfine S0 and 35s belied gypsum In SSP to soil organic 35s forms occurred in the first 30 days after application. The organic 35s activity formed from 35s0 was twice that formed from sulphate-based fertilizer and was mainly carbon- bonded 35s in the top 33mm of the pasture soil profile. The amount of organic 35s remaining as carbon-bonded 35s decreased with soil depth and the reverse occurred for the estersulphate 35s. By 1 50 days, greater activity from the microfine 35s0 remained in the soil organics fraction than from the sulphate-35s fertilizer, indicating that more soil organicS reserves may be formed through the use of fine S0 fertilizer than from the sulphate-based fertilizer. This also indicated the advantage of using S0 in minimizing the S leaching losses in this aquic environment. An inverse dilution technique using an isotope injector developed at Massey University to uniformly label undisturbed soil cores with carrier-free 35so4= solution was used to measure the impact of S0 and sulphate-based fertilizers on the fate of soil S. Results were consistent with the labelled fertilizer technique and both techniques indicated rapid incorporation of 35s into soil organic S and that the carbon-bonded S formed was likely to be a subsequent source of mineralized S available to plants. Soil samples from the preliminary field study were used to evaluate soil preparation and extraction techniques. Soil sampling and preparation techniques were evaluated on the basis that an extract sampling the plant available S pool in soil should have the same 35s specific activity as plant growing on that soil. The average 35s specific activity in a calcium dihydrogen phosphate (CaP-S) (0.04 M) extract from a freeze-dried sample of the top 60 mm of a pasture soil was most closely related to the 35s specific activity of plants growing on that soil. CaP-S extracts from field-moist soil or 0.01 M CaCI2 extracts from field-moist or freeze-dried soils had higher specific activities than plants. lt was concluded that plants were able to extract soil S from soils which was not exchangeable with added 35so4= fertilizers during either the field experiment or extraction with 0.01 M CaCI2. The second series of field and glasshouse trials were conducted to investigate the fate of 35s labelled SSP, gypsum and S0 of varying particle sizes (0 . 1 50 m m) which had not oxidized, the major fate of fertilizer 35s, either under glasshouse or field conditions, was again in soil organic matter mostly formed in the top 33 mm of the soil. Applications of gypsum and SSP caused 35s to move to the 33-1 00 mm soil depths but there was no additional influence of P on the depth to which so4= was leached. A preliminary computer simulation model describing the fate of 35so4 =-s fertilizer was developed. The model provided a very accurate method of predicting plant uptake of S from both SSP fertilized and u nfertilized soil cores. The model also indicated that, at any particular soil depth, on average, actual rates of mineralizatio n a nd i m mobilization may exceed root uptake of S by 1.5 to 2 fold (mg S turned over per unit of S taken up by plants). The accuracy of the estimated turnover rate could not be validated because the model gave relatively inaccurate predictions of the measured movement and transformations of 35s tracer added to the soil as SSP. There was, however, relative similarity between the observed and predicted proportional distribution of 35s between soil and plant S forms. Such a distribution supported the concept of using root activity as a modifier of mineralization and immobilization rates in order to describe the extent of these processes at different soil depths. The study has emphasized the greater importance of the surface few millimeters of pasture soil in S transformations, important in the fate of fertilizer and pasture plant nutrition. There appears to be scope in manipulating S0 particle size to improve the efficiency of the S fertilizer used.

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  • Biogeochemical studies of nickel and copper in New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University

    Timperley, Michael Horace (1971)

    Doctoral thesis
    Massey University

    The accumulations of various metals by some indigenous trees growing on the Riwaka Basic Complex, North-west Nelson, New Zealand, were investigated by the application of statistical techniques to biogeochemical data. Particular reference was given to nickel and copper to evaluate the usefulness of plant analysis as a prospecting tool. Preliminary investigations showed that serious errors could result from the methods of sampling plants and soils and sampling procedures were adopted to minimise these errors. In addition, errors arising from atomic absorption analysis were found to be significant for some metals. Leaves and twigs from three Nothofagus species, W.racemosa and Q.acutifolia as well as their associated soils, were collected and analysed for nickel, cobalt, copper, zinc, chromium, calcium, magnesium, manganese and potassium. The plants were also analysed for iron. These results showed that each species accumulated different, but related, amounts of various metals and that they distributed these metals in different ways between their leaves and twigs. N.truncata and N.fusca which are closely related genetically, accumulated metals to similar degrees, while N.menziesii which is not closely related to the other Nothofagus species accumulated metals to differing degrees. Relationships between the metal concentrations in the plants and in the soils were evaluated by computing correlation coefficients. The best correlations for nickel were obtained for the Nothofagus genus although the other species also showed highly significant correlations. The Nothofagus genus also showed the best correlation for copper. In view of the above results, a more extensive study of the Nothofagus genus was carried out. A second survey was undertaken in the same area in which leaf samples of this genus as well as their associated soils were collected. While the metal concentrations in the soils collected in this survey compared well to those collected previously, the metal concentrations in the plants, in general, did not show good agreement. Trend analysis was used to compare in detail the nickel and copper contents in the leaves of the Nothofagus genus with the concentrations of those metals in the soils. It was shown by comparison of the trend surfaces and residuals that the accumulation of nickel was determined primarily by the concentration of nickel in the soil, whereas for copper the accumulation by the plant was a function primarily of the specific requirement of the plant for this metal. Multiple regression analysis was used to improve the prediction of the copper and nickel concentrations in the soil from the concentrations of these metals in the leaves of the Nothofagus species, by making quantitative allowance for the processes influencing the accumulation of these metals by the plants. Improvements of between 25% and 35% were obtained at the 90% confidence level. Inter-metal ratios in the leaves were considered as possible indicators of nickel and copper concentrations in the soil but the results were discouraging. Studies were made of the locations and chemical forms of nickel, copper, zinc and iron in both freeze-dried and fresh leaves from some trees growing on the Complex. Atomic absorption spectrophotometry was used to measure the concentrations of these metals in both plant extracts and on the electrophoresis and chromatography papers used to separate the metal complexes in the extracts. Results indicated that the major part of the nickel present in the leaves was not contained in cell organelles nor was it bound to cell walls, but existed as a positively charged complex in either the cytoplasm and/ or the vacuole. Copper, zinc and iron were distributed differently with varying fractions, depending on the metal, existing predominately as anionic complexes. It was concluded that the research embodied in this thesis had illustrated the application of statistical techniques to biogeochemical studies, showed that biogeochemical prospecting for nickel in New Zealand was feasible and that methods of total analysis for metals could be applied to the study of microgram amounts of metals in biological systems.

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  • 'An education system characterised by equity' : a critical evaluation of educational change in Samoa, 1995-2005 : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Education at Massey University, Palmerston North, New Zealand

    Male, Alan G R (2011)

    Doctoral thesis
    Massey University

    The problem investigated in this thesis arose from my professional practice as a consultant with regard to educational reforms in a number of countries, including Samoa. This created an initial interest in why different policy options were chosen by different countries in response to similar problems. Observation of the implementation of reforms in various contexts also created questions as to why the implementation of reforms often seemed to lead to new formulations of the original arrangements, resulting in development but little change. A prior review of evaluations of educational reform programmes showed that many educational evaluations are confined to matters of technical advice inputs, resource management and the achievement of milestones. This study however, considers other factors relevant to the successful achievement of an educational reform programme situated within a particular social, political and historical context. In particular, this thesis reports on a critical evaluation of the development, between the mid-1980s and 1994, of a policy aimed at producing an education system “characterised by equity” (Department of Education, 1995) in Samoa and then on the results of the implementation of that policy between 1995-2005. The study focused first on the differences in the performance of student groups based in the national Year 8 secondary school selection examination and in their subsequent access to secondary schooling and to the achievement outcomes in Year 12 over the period between 1994 and 2008. Information was gathered through analysis of national examination results databases. Additional information was gathered through interviews and questionnaires from senior educational system managers and from the principals of a sample of four secondary schools. Questionnaires, aimed at gathering socio-economic data, were administered to 2000 students and their families from Years 9, 11, 12 and 13 at the sample schools. The evidence showed little change in the patterns of achievement between advantaged and disadvantaged groups. The system had expanded but the patterns of inequity remained unchanged. The reasons for the selection of the reform options that resulted in the maintenance of disparities through the 1995-2005 programme were found in the history, culture and political setting of Samoa. Because of the small size and ethnic and cultural homogeneity of the population, the evaluation was based on the theories of Pierre Bourdieu. Bourdieu’s concepts of field practice and habitus showed how the policy options included in the reform programme were influenced by an underlying habitus that generated the desire for change but also constrained the achievement of the stated aim of a “system characterised by equity”. The research showed how the historical background to the patterns of advantage within the system and the structure and patterns of advantage that resulted from the reforms continued beyond the reform.

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  • The impact of anxiety, depression, and cognitive factors associated with anxiety, on everyday risk taking behaviour : a thesis presented in partial fulfilments [sic] for the degree of Doctor of Clinical Psychology at Massey University, Wellington, New Zealand

    Hunt, Brett David (2012)

    Doctoral thesis
    Massey University

    Research into risk taking behaviour (RTB) reveals that depression and anxiety (in particular) are associated with risk aversive behaviour, for many different types of risks, including gambling, simulated risk taking tasks, and everyday risks. There has, however, been little research into the relationship between cognitive factors associated with anxiety, and RTB. This is in spite of research in this area finding that perceived risk had a stronger relationship with a cognitive factor (worry) than with anxiety. The present research is investigating the everyday RTB associated with depression, anxiety, and cognitive factors associated with anxiety. Everyday risks are the type of risks being investigated as these are decisions people make on a daily basis that involve risk that cannot easily be avoided, and being overly avoidant of these risks can lead to negative consequences. This research is split into two studies, with the first study split into two sections. The first part of study one is the continued development of a measure of everyday RTB across multiple domains. All existing measures of everyday RTB either do not measure RTB in different domains, or have psychometric problems. Therefore, the development of a measure suitable for use in this research project is required. The second part of the first study is investigating the relationships of anxiety and depression level with everyday RTB, across multiple domains. Study one used three samples, New Zealand community and tertiary student samples, and an international internet sample. The second study is investigating the relationship between cognitions associated with anxiety (e.g. worry and metaworry) and everyday RTB. This study used two samples, a New Zealand tertiary student sample, and an international internet sample. Results from the development of the everyday risk taking measure indicate that the measure that underwent further development, the Everyday Risk Inventory – Expanded (ERI-E) is a reliable measure of everyday RTB, for general community samples in particular. Cronbach’s alpha values for the community sample were all above 0.7, but in some domains for the student sample were just below 0.6. Confirmatory factor analysis showed the fit for both the multiple domain and single domain models were moderate to good. Results from the second part of study 1 showed that the relationships of anxiety and depression, with everyday RTB were weak, with few significant results from either correlational or multiple regression analysis. In particular, depression has a minimal impact on RTB. Sociodemographic factors, particularly age, gender and income had more significant impacts on everyday RTB, with people on lower income, and older people, being risk averse. Gender differences varied between domains, with females significantly more risk averse for risks involving personal danger and risks to others. The concept that differences in people’s sense of power within their society affects RTB was supported, as in general socio-demographic differences associated with increased power (e.g. higher income and being male) led to people being less risk averse. Results from study two showed that everyday RTB has a stronger association with cognitive factors associated with anxiety than to anxiety level. In particular it has high correlations with worry and intolerance of uncertainty (IU). Structural equation modelling found that a model with cognitive factors leading to anxiety and differences in everyday RTB was an almost perfect fit for the model, and anxiety had no direct effect on RTB. It was also found that the relationship between everyday RTB and cognitive factors was stronger for high anxiety levels than low anxiety levels. Further research is required to determine the reason why cognitive factors associated with anxiety affect everyday RTB, rather than anxiety level. The present research contributes to knowledge in this area by showing that cognitive factors impact on RTB, rather than anxiety level. It also found that socio-demographic characteristics, particularly age, were more important in explaining differences in RTB than was found in previous research.

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  • Non-parametric estimation of geographical relative risk functions : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Statistics at Massey University, Palmerston North, New Zealand

    Fernando, W. T. P. Sarojinie (2012)

    Doctoral thesis
    Massey University

    The geographical relative risk function is a useful tool for investigating the spatial distribution of disease based on case and control data. The most common way of estimating this function is using the ratio of spatial kernel density estimates constructed from the locations of cases and controls respectively. This technique is known as the density ratio method. The performance of kernel density estimators depends on the choice of kernel and the smoothing parameter (bandwidth). The choice of kernel is not critical to the statistical performance of the method but the bandwidth is crucial. Di erent bandwidth selectors such as least squares cross validation (LSCV) and likelihood cross validation (LCV) are chosen to control the degree of smoothing during the computation of the density ratio estimator. An alternative way of estimating this relative risk function is local linear regression approach. This deserves consideration since the density ratio estimator can be less natural when the relative risk has a global trend, as one might expect to see when there is a line source of risk such as a polluted river or a road. The use of local linear regression for estimation of log relative risk functions per se has not been examined in any detail in the literature, so our work on this methodology is a novel contribution. A detailed account of local linear approach in the estimation of log relative risk function is provided, consisting of an analysis of asymptotic properties and a method for computing tolerance contours to emphasize the regions of signi cantly high risk. Data driven bandwidth selectors for the local linear method including a novel plug-in methodology is examined.A simulation study to compare the performance of density ratio and local linear estimators using a range of data-driven bandwidth selectors is presented. The analysis of two speci c data sets is examined. The estimation of the spatial relative risk function is extended to spatio-temporal estimation through the use of suitable temporal kernel functions, since time-scale is an important consideration when estimating disease risk. The extended version of the kernel density estimation is applied here to compute the unknown densities of the spatio-temporal relative risk function. Next we investigate the time derivatives of the space-time relative risk function to see how the disease change with time. This discussion provides novel contributions with the introduction to time derivatives of the relative risk function as well as asymptotic methods for the computation of tolerance contours to highlight subregions of signi cantly elevated risk. LSCV and subjective bandwidths are used to compute these estimators since it performs well in density ratio method. The analysis on a real application to foot and mouth disease (FMD) of 1967 outbreak is employed to illustrate these estimators. The relative risk function is investigated when the data include a spatially varying covariate. The discussion produces the introduction to generalized relative risk function in two ways and also asymptotic properties of estimators for both cases as novel works. Generalized kernel density estimation is used to replace the unknown densities in the relative risk function. Asymptotic theories are used to compute tolerance contours to identify the areas which show high risk. LSCV bandwidth selector is described in this estimation process providing the implicit formulae. We illustrate this methodology on data from the 2001 outbreak of FMD in the UK, examining the e ect of farm size as a covariate.

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  • The effect of water stress on water relations, carbon isotype discrimination, and shoot and root growth of sainfoin (Onobrychis viciifolia Scop.) and lucerne (Medicago sativa L.) : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Department of Plant Science at Massey University

    Mir-Hosseini-Dehabadi, Seyed Reza (1994)

    Doctoral thesis
    Massey University

    Sainfoin (Onobrychis viciifolia Scop.) is a useful forage legume regarded as having drought resistant attributes. Also, it does not cause bloat in ruminants and is not sensitive to alfalfa weevil (Hypera postica. L). Although the physiological and morphological responses to water stress of lucerne (Medicago sativa L.) are well known the responses of sainfoin to water stress have not been fully studied. In this study the physiological and morphological responses of sainfoin to water stress were investigated, with lucerne used as a reference plant. The results of the indoor and outdoor studies showed sainfoin had useful characteristics for forage production in dry conditions. Relative to lucerne it had a lower yield, due to lower leaf area, lower stem number and poor regrowth. However, sainfoin responded to water stress at least as well as lucerne. Sainfoin had a higher root:shoot ratio and a lower specific leaf area ratio than lucerne, indicating a higher allocation of carbohydrate to the roots, and a lower leaf surface area for transpiration in sainfoin than for lucerne. Water stress decreased the yield of lucerne proportionally more than sainfoin mostly due to the greater reduction in the above ground dry weight of lucerne. The indoor study of root characteristics of sainfoin and lucerne in 1m tall tubes showed that in terms of root development sainfoin responded to water stress better than lucerne. Although sainfoin had equal root mass and root length to lucerne, the root distribution of sainfoin at below 0.6 m depths was greater than for lucerne. As water stress developed sainfoin roots grew below 0.6 m earlier than lucerne roots. Sainfoin had a higher root osmotic adjustment than lucerne and also maintained higher (less negative) leaf water potential than lucerne. The stomatal resistances (Rs) of sainfoin and lucerne were equal, but Rs was not distributed equally between adaxial and abaxial leaf surfaces. The Rs of the adaxial leaf surface of sainfoin was lower and more sensitive to water stress than the Rs of the abaxial leaf surface. The different Rs of the adaxial and abaxial leaf surfaces of sainfoin was partly due to the different stomatal frequencies of the respective surfaces. Comparison of sainfoin cultivars in a climate room showed that the water use efficiencies (WUE) of Remont, Fakir, Cotswold-Common, and Eski, were similar. Remont was more sensitive to water stress than the other three cultivars, and Eski produced a greater root length and mass than other cultivars. The growth of Eski was initially slower than that of the Remont in both the indoor and the outdoor studies. However, lucerne grew faster than all the sainfoin cultivars. Over three harvests in the field the yields of Eski and Remont were similar but lucerne out yielded both sainfoin cultivars. Sainfoin produced a greater proportion of its yield earlier than lucerne, whereas lucerne distributed its yield throughout the whole season, indicating that sainfoin is adapted to regions with precipitation in only winter and spring. The results of the carbon isotope discrimination (Δ) analysis for the indoor and outdoor studies showed Δ had a negative correlation with WUE, leaf water potential, osmotic potential, and stomatal resistance, but had a positive correlation with relative water content, turgor potential, transpiration rate, and photosynthetic rate. These correlations demonstrated the usefulness of this technique for evaluating the responses of plants to water stress. The stressed plants always had lower Δ than the control plants showing the higher WUE of stressed plants. The Δ of roots was higher than the Δ of the leaves suggesting that the growth of leaves occurred in conditions that were an average drier than for the growth of roots. This was supported by the lower (more negative) water potential of leaves than roots. The Δ of the roots below 0.6 m depth was higher than the Δ of roots above 0.1 m depth suggesting the roots above 0.1m grew under higher water stress than the roots below 0.6m depth. Over three harvests in the field the Δ of Eski and lucerne were similar and the Δ of Remont was higher than for Eski and lucerne. In conclusion, sainfoin was found to have several useful attributes for growth and survival in dry regions. Of the sainfoin cultivars examined Eski was the best adapted to water stress. Relative to lucerne, sainfoin yielded less, but had a similar water use efficiency, a shorter season of growth, a greater root: shoot ratio, deeper roots and better maintenance of leaf water potential under water stress.

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  • Studies on Cooperia curticei (Ransom 1907) a nematode parasite of sheep : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy

    Ahluwalia, Jagjit Singh (1970)

    Doctoral thesis
    Massey University

    This thesis records in part I studies on the ecology of the free living stages of Cooperia curticei , both under controlled and natural conditions. At constant temperatures free living stages developed throughout the temperature range of 10-37c. At all temperatures each larval stage occupied the same proportion of the total developmental time to reach the infective stage. The relationship between the rate of development in log days and temperature was found to be linear. Under natural conditions the rate of development was most strongly correlated with mean maximum air temperature and was not significantly different to that observed under controlled conditions. When faecal cultures were kept at 10°C, 27°C and 37°C a higher proportion of eggs completed development to the infective stage at 27°C than at the other temperatures. Under natural conditions the percentage recovery was influenced by weather conditions particularly rainfall. Submergence of the free living stages in water inhibited their further development. First and second stage larvae survived longest at temperatures between 5°C and 15°C but for a much-shorter time than infective larvae. Between the extremes of -6 and 52°C, the longest survival of infective larvae was 312 days at 10°C. Techniques are described for the recovery of Cooperia curticei larvae from sample units of pasture, soil and faecal pellets. Under natural conditions the maximum survival of larvae from monthly experiments ranged from 9 - 26 weeks. Maximum survival was particularly influenced by temperature. Infective larvae survived through the winter. There was an exponential relationship between the percentage survival and percentage of larvae recovered from the herbage. Vertical migration of larvae appeared to be primarily affected by rainfall and evaporation. It is concluded that infective larvae of Cooperia curticei are available to grazing sheep throughout the year. Theoretically the nematode can complete from 9 - 11 generations in each year. Part II of this thesis records experiments on the relationship between Cooperia curticei and the host sheep. Experiments carried out in vivo and in vitro demonstrated that infective larvae of C. curticei exsheath under conditions provided by the rumen. The process of exsheathment was similar to that described for H. contortus. A series of experimental observations were made on the effect of Cooperia curticei infection in sheep using animals of differing ages, on different diets and with various sizes of infection. The prepatent period of infection was 14- 16 days. Peak egg counts were recorded 5 - 7 days after infection became patent . There after they declined gradually in sheep given 10,000 larvae but in sheep given 50,000 to 100,000 larvae the decline was more abrupt. The egg output per female worm was found to range up to 1,958 eggs per day. No clinical sign of infection was observed from any experimental animal. Body weights, wool growth and blood analyses showed no significant changes and no gross lesions or significant histopathological changes were observed. The results indicate a well balanced relationship between C. curticei and the sheep. The distribution of the C. curticei in the small intestine was skewed, and most of the worms were recovered from 5- 10 feet from the gastric pylorus. A predominance of female worms was observed at all levels of the small intestine. Maximum percentage recovery of C. curticei was observed in sheep given 10,000 larvae. Experimental animals with higher doses besides giving a lower rate of recovery showed inhibition of development and stunted growth of worms. Serum and intestinal mucus samples from infected animals were tested for precipitating antibodies by gel diffusion against five antigens. Antigens were prepared from first stage, second stage, ensheathed third stage, exsheathed third stage larvae and exsheathing fluid. Variable numbers of precipitin lines were obtained with serum and mucus from infected sheep more than 6-7 months old. Sheep 2-3 months old showed no such response but did show evidence of an acquired resistance to infection.

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  • Studies towards the chemical synthesis of the 18 kDa antigenic protein from Mycobacterium leprae : a thesis presented in partial fulfilment of the requirements for the degree of Ph. D. in Chemistry at Massey University

    Love, Stephen George (1991)

    Doctoral thesis
    Massey University

    This thesis describes the solid phase synthesis of a series of peptides from the antigenic Mycobacterium leprae 18 kDa protein and the total synthesis of the 148 amino acid protein. The peptides were synthesised using an Applied Biosystems 430A Solid Phase Peptide Synthesiser usually modified by the removal of in-line filters to the reaction vessel to allow the synthesis of the peptides using programs evolved by S.B.H. Kent. The peptides were cleaved from the peptide resin using liquid HF and purified by reverse phase HPLC. The first series of peptides to be synthesised revolved around a monoclonal antibody binding site. These peptides were SLP-1, (101-115, RILASYQEGVLKLSI), SLP-2, (111-124, LKLSIPVAERAKPRK), SLP-3, (121-134, AKPRKISVDRGNNG) and SLP-4 (109-125 GVLKLSIPVAERAKPRK). The other peptides were synthesised as a series of overlapping 20 mers covering the entire 148 amino acid sequence. These peptides are SLP-5 (1-20, MLMRTDPFRELDRFAEQVLG), SLP-6 (16-35, EQVLGTS ARPAVMPMDAWRE), SLP-7 (31-50, DAWREGEFVVEFDLPGIKA), SLP-8 (46-65, PGIKADSLDIDIERNVVTVR), SLP-9 (61-80, VVTVRAERPGVDPDREMLAA), SLP-10 (76-95, EMLAAERPRGLFNRQLVLGE), SLP-11 (91-110, LVLGENLDTERIL ASYQEGV), SLP-12 (106-125, YQEGVLKLSIPVAERAKPRK), SLP-13 (121-140, AKPRKISVDRGNNGHQTINK) and SLP-14 (136-148, QTINKTAEHEIIDA). Two other peptides SLP-15 (101-125, RILASYQEGVLKLSIPVAERAKPRK) and SLP-16 (91-115, LVLGEIVLDTERILASVQEGVLKLSI) were also synthesised. The peptides were used in immunological studies that determined the location of the L-5 monoclonal antibody binding site and showed where T-cell stimulation sites are located on the 18 kDa protein in murine systems. The synthesis of larger 50 amino acid fragments of the 18 kDa protein, peptides SLP-17 (101-148), SLP-18 (50-100) and SLP 19 (1-50) was carried out in order to determine if it was possible to synthesise the total 18 kDa protein. These fragments were synthesised in a similar manner to the previous peptides. From the synthesis of these peptides it was decided that the total synthesis of the 148 amino acid protein was possible. The synthesis of the 18 kDa protein was carried out using Kent's protocols as a single step process. The synthesis was monitored up to the 100th amino acid by ninhydrin assay with no failed couplings detected. The coupling percentages for all of the amino acids was achieved by peptide resin sequencing where the average percentage couplings were shown to be 99.49% with an overall yield for the protein on the resin of 49%. After Lo-Hi HF cleavage purification of the protein was hampered by the formation of aggregated products which proved initially to be inseparable from the protein. By sequencing some partially purified protein it was shown that under certain cleavage conditions the benzyl ether side chain protecting group was present on the threonine amino acids at positions 5 and 21. A further treatment of the protein using a hard acid-soft base mechanism with trimethylsilyl trifluorosulphonate/thioanisole was used in these cases to remove the remaining benzyl protecting groups. An attempt to overcome the aggregation of the protein involved the addition of SDS to the HF cleavage vessel. After purification the protein showed no signs of the aggregation products. A 90 amino acid fragment removed during the course of the synthesis of the 18 kDa proteien was cleaved and dissolved in 6M guanidine.HCl. After gel filtration on a Sephadex G-50 column, preparative HPLC was carried out on the isolated protein peak. The protein was then gel filtered again on a Sephadex G-50 column using 6M guanidine.HCl which separated the aggregated product to give a pure 90 amino acid protein after dialysis. The full synthetic 18 kDa protein was purified in a similar manner to the 90 amino acid fragment with the second gel filtration being carried out using a Sephadex G-100 column or a Pharmacia Superose 12 column. This provided pure synthetic 18 kDa protein in an estimated 1.8 % yield or 47 mg from this synthesis of a final 2.46 g of protein resin based on the starting protein on the resin.

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  • The neotectonics of the Wellington and Ruahine faults between the Manawatu Gorge and Puketitiri, North Island, New Zealand : a thesis presented as partial fulfilment of the requirements for the degree of Doctor of Philosophy in Earth Science

    Hanson, Judith Ann (1998)

    Doctoral thesis
    Massey University

    The Wellington and Ruahine Faults are two major faults of the North Island Dextral Fault Belt which formed approximately 2.5ma in response to the obliquely subducting Pacific Plate beneath the east coast of the North Island. Plate rotation has increased over time causing faulting patterns to change throw direction and strike-slip activity to increase within the Hawkes Bay area. Earthquakes rupturing either the Wellington or Ruahine Faults represent a serious hazard for this area. The purpose of this study was to establish a record of paleoseismic activity on the Wellington and Ruahine Faults which would allow future estimates of likely fault behaviour to be made. Trenches were excavated across these faults in mainly swampy environments. Within these trenches are layers of earthquake debris, layers of peat and other terrestrial sediments which have been deformed by earthquake activity. The layers of peat were radiocarbon dated to give the approximate ages of underlying or overlying earthquake debris. In many areas through which the faults pass are terraces composed of gravel which has been washed down from the axial ranges composed of Torlesse greywacke. The ages of these terraces are known due to layers of dated volcanic ash preserved in cover beds and wood preserved within. Some of these terraces have been offset by the fault. Using the known age of these terraces and the distance that they are offset by the fault, it was possible to calculate rates of fault movement during late Quaternary time. Field observations of the Wellington and Ruahine Faults reveal that the faults do not deform the areas through which they pass but rather act in response to regional deformation (within these structurally different areas). During earthquake events large blocks of land are moved both horizontally and vertically. The rate and size of these events is dependent on the regional geology where the earthquake ruptures occur. These regions are described as follows from south to north. The first region lies between Kahuki and the Ohara Depression, this is an area of prevalent strike-slip with horizontal offset rates averaging 12mm/yr for the Wellington Fault which is high by world standards. In contrast the Ruahine Fault displays little evidence of late Quaternary movement. The second region encloses the Ohara Depression which has an east-west compressional vector. Here strain is transferred from the Wellington to the Ruahine Fault thereby lowering the horizontal offset rate for the Wellington Fault to a maximum of 4.7mm/yr. The third region lies between the Ngaruroro and Tutaekuri Rivers and is a region with a north-northeast compressional vector. Here a horizontal offset rate of 3.3mm/yr (for the Wellington Fault) was determined using offset Ohakean terrace rises. The most northern region lies between the Tutaekuri River and Napier-Taupo Highway is a zone of normal strike-slip faulting with a combined horizontal offset rate of 18mm/yr for the Wellington, Ruahine and Te Waka Faults. These regions correspond to proposed rupture segments for both Wellington and Ruahine Faults. This study provides a record of at least 12 Ms >6.5 earthquake events recorded on the Wellington Fault in the Kahuki-Dannevirke district, 9 of which occurred in the last 30,000 years. This is the longest record of earthquake events recorded within fault trenches in New Zealand. The last earthquake on the Wellington Fault took place c. 300 years ago between Kahuki and Dannevirke. The largest single offset found in the Kahuki-Dannevirke area is estimated to have been displaced by 12m horizontally and 1.8m vertically. The estimated magnitude for an earthquake occurring in this region is between Ms 7.4 and 7.8. An earthquake of this magnitude would cause major destruction to all nearby engineering structures and to buildings in the nearby cities of Palmerston North, Napier and Hastings. Earthquakes of this size are estimated to occur every c. 300 years for the Kahuki-Dannevirke area, every 300 to 500 years for the Ohara Depression and every 1000 years for the region between the Tutaekuri River and the Napier-Taupo Highway. Similar studies were conducted along the Ruahine Fault trace between the Ohara Depression and the Napier-Taupo Highway. Seismic activity in this area is estimated to produce a Ms 7.4 to 7.5 magnitude earthquake every 400 to 500 years. Horizontal offset is expected to be in the range of 3 to 5.5m. Dates for the last earthquake on the Ruahine Fault have not been determined but it is possible that there have been up to 4 earthquakes on this fault since 1850 yrs B.P. The Wellington and Ruahine Faults pass mainly through farmland, areas of forestry and the southern Ruahine Range. When an earthquake rupture event occurs it is possible that most farmhouses will escape major damage with little loss of life, providing they are not built on the fault or in the path of any possible landslides. However major disruption is to be expected to any engineering works close to the faults. Landslides may occur on over-steep slopes in and near the axial ranges and some major rivers may be dammed as a result. The larger magnitude earthquakes will produce severe shaking in the cities of Palmerston North, Napier and Hastings where substantial damage can be expected to occur, especially to those buildings that are built on reclaimed land or on alluvial soils prone to liquefaction.

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  • Studies on the binding of iron and zinc to milk protein products : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology, Riddet Centre and Institute of Food, Nutrition and Human Health

    Sugiarto, Maya Wulansari (2004)

    Doctoral thesis
    Massey University

    The principal objective of this study was to characterize the binding of iron and zinc to three commercial milk protein products; namely sodium caseinate, whey protein isolate (WPI) and milk protein concentrate (MPC). The mineral-protein mixtures were prepared by mixing either iron (FeSO4.7H2O) or zinc (ZnSO4.7H2O) at a range of concentrations with 1% protein solutions (e.g. sodium caseinate), in 50 mM HEPES buffer at pH 6.6. The mineral-protein mixtures were then centrifuged (10,800 g, 20 min) to separate the soluble protein and soluble minerals from the insoluble protein and insoluble minerals. The supernatant, which contained the soluble fractions, was carefully removed and passed through an ultrafiltration membrane to separate "free" minerals from the minerals bound to the soluble proteins. Under the experimental conditions used in the study, aqueous solutions of ferrous sulphate were relatively insoluble. This was due mainly to the oxidation of ferrous sulphate to the insoluble ferric hydroxide. The addition of a 1% sodium caseinate solution markedly improved the solubility of ferrous sulphate due to the binding of iron to the caseins. The casein molecules were able to bind up to 8 moles Fe/mole protein. Addition of iron above a certain critical concentration (approximately 4 mM) caused the aggregation and precipitation of casein molecules. The loss of solubility was due mainly to the neutralisation of the negative charges on the casein molecules by iron with a consequent decrease in the electrostatic repulsions between the protein molecules. In contrast to the behaviour of the sodium caseinate, the interactions of iron with the whey protein molecules in WPI did not cause significant precipitation of the iron-WPI mixtures. Whey proteins remained soluble up to a concentration of 20 mM added iron and were able to bind up to approximately 7 moles Fe/mole of protein. Analysis of the binding curves by Scatchard plots showed that sodium caseinate has a higher binding affinity for iron (log Kapp = 5.3) than WPI (log Kapp = 3.6). This confirmed the experimental observation that in sodium caseinate solutions, up to the critical concentration of iron, virtually all iron was bound to the protein molecules whereas in WPI solutions, a small amount of free iron was present. The strong affinity for iron shown by the casein molecules is due mainly to the presence of clustered phosphoserine residues, which are absent in whey proteins. The binding characteristics of iron to MPC were broadly similar to those for sodium caseinate. However, soluble MPC was able to bind greater amount of iron (45 mg Fe/g protein) than soluble sodium caseinate (20 mg Fe/g protein). In MPC, casein molecules exist in the micellar form and iron was likely to be bound to both the caseins and the colloidal calcium phosphate, probably displacing calcium ions in the process. The binding properties of proteins were significantly affected by changes in pH. As the pH was decreased from about 6.5 to 5.0, there was a marked decrease in the ability of proteins to bind cations. For example, the amount of iron bound to WPI decreased from approximately 8 to 1 mg Fe/g soluble protein as the pH dropped from 6.5 to 5.0. This decrease was presumably due to the change in the ionisation state of the negatively charged residues. In the case of sodium caseinate and MPC, the situation was complicated by the marked loss of protein solubility at pH values ≤ 5.0. The binding characteristics of zinc to the three milk protein products were broadly similar to those for iron. For sodium caseinate and MPC, there was a critical concentration of added zinc above which proteins lost solubility. Sodium caseinate showed a greater binding affinity for zinc than WPI (Log Kapp values were 4.8 and 3.3 respectively), while MPC was able to bind more zinc (25 mg Zn/g protein) than sodium caseinate (14 mg Zn/g protein). However, there was one distinctive difference between the binding behaviour of iron and zinc. In the case of WPI, addition of zinc caused precipitation of whey proteins at a concentration above 4 mM added zinc. This was due to the specific binding sites for zinc in the α-lactalbumin fractions. Oxidation tests, using linoleic acid as the substrate, showed that iron-protein mixtures were able to markedly suppress the rate of oxidation compared to free iron. Among the iron-protein mixtures, iron-sodium caseinate and iron-MPC mixtures suppressed the oxidation rate to a greater extent than iron-WPI mixtures. In iron-sodium caseinate and iron-MPC mixtures, the iron was completely bound to the protein whereas in iron-WPI mixtures, there was still a small amount of unbound iron, which could cause oxidation. The data obtained from this study will provide valuable information for the production of mineral-protein complexes with good functional properties, which could be used as a source of ingredients in other food products.

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  • Women, politics and the media : the 1999 New Zealand general election : a thesis presented in partial fulfilment of the requirements for the degree of PhD in Communication & Journalism at Massey University, Palmerston North, New Zealand

    Fountaine, Susan Lyndsey (2002)

    Doctoral thesis
    Massey University

    New Zealand's shift to a Mixed Member Proportional (MMP) system of government contained a two-fold promise for women. Explicitly, there was the prospect of increased electoral diversity, meaning more women in Parliament, and implicitly, there was a promise of better political reporting and therefore qualitatively better coverage of women. The country's second proportional representation election campaign, in 1999, appeared to deliver on these promises. The 1999 General Election was historically significant because it featured two women - incumbent Jenny Shipley and Labour leader Helen Clark - contesting the role of Prime Minister. Female politicians also featured in important electorate races, and made the headlines during New Zealand First's gender-based list controversy. According to one media commentator, women determined the outcome, dominated the news and changed the nature of the campaign (Harris, 2000). However, popular opinion that women influenced the character of the campaign, and especially that they dominated the campaign, is in contrast to empirical research, from around the world, which has consistently suggested women politicians receive less news coverage, are "framed" or packaged in stereotypically feminine ways, and ultimately disadvantaged by traditional news coverage (e.g. Bathla, 1998; Braden, 1996; Gidengil & Everitt, 1999; Herzog, 1998; Norris, 1997c; van Acker, 1999). Therefore, the main aim of this study was to explore, using a combination of corroborative methodologies, how and why the news media covered female politicians during the 1999 election campaign. Three methodologies (content analysis, qualitative interviews, and a case study), and a framing typology, were employed. Content and frame analysis showed that female politicians were used as news subjects to a comparable, if not better, extent than men but were marginalised as political news sources. In other words, there was a tendency for women to be talked about, rather than talked to. This reflects dominant news structures and, in some cases, the women's own approach to self-promotion. It was also revealed that female politicians were subjected to more polarised media coverage, influenced by status, incumbency and context, and again, partly a result of their own positioning. There were significant differences in media coverage of men and women, but framing of political news did little to advance women's perspectives, suggesting election campaigns that ostensibly feature women are not necessarily of a different nature. Overall, these results suggest a blurring of the traditional "public/private" dichotomy, as an outcome of changes in the media (such as the contemporary trends toward personalisation and "celebrification") and women's campaigning. Gender remains a factor in the presentation and interpretation of political women, by the news media (which, for example, portrayed the female leaders as Xena princesses) and by the women themselves (for example, Shipley portrayed herself as a mother figure). To some extent, there appears to have been a maturing of political journalism about women but it is too soon to tell if the shift to MMP has resulted in any significant longterm change for female politicians. However, this unique study, in examining the media-politics-gender nexus in the 1999 General Election campaign, focuses attention on the two-fold promise of MMP for women, and explores the extent to which the new political system and the media have begun to deliver. On a practical level, the thesis concludes that it is important to encourage female politicians to work within, and use the current system to their advantage. However, it also urges researchers to take a critical approach to exploring the systemic socialisation and pervasive news structures, processes and values that contribute to women's ongoing political marginalisation. Finally, the thesis considers the wider implications for women, the news media, and the electoral system.

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  • Some aspects of the epidemiology of neosporosis in sheep in New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Science at Massey University, Palmerston North, New Zealand

    Syed-Hussain, Sharifah Salmah (2014)

    Doctoral thesis
    Massey University

    Recent reports from New Zealand indicate Neospora caninum may have a role in causing reproductive problems in sheep. However, knowledge about the epidemiology of neosporosis in sheep in New Zealand is limited. Thus, the research presented in this thesis was undertaken to further understand the mode of transmission, seroprevalence, diagnosis and treatment of N. caninum in sheep in New Zealand. The initial study investigated venereal and vertical transmission. The results suggested that although N. caninum DNA can be found in the semen of experimentally infected rams (n=16), the transmission of N. caninum to ewes (n=16) via natural mating is unlikely. In a two year study, ewes inoculated prior to mating (n=25 in Year 1; n=7 in Year 2) did not have congenitally infected lambs that year (n=0/44) but did in Year 2 (n=7/11). Ewes re-inoculated on Day 120 of gestation in Year 2 (n=9) had congenitally infected lambs (n=12/12) with more severe lesions than those not re-inoculated (n=2/11) indicating that the initial inoculation did not induce protection. Ewes inoculated for the first time on Day 120 of gestation (n=12) gave birth to lambs (n=10) that were all congenitally infected. Treatment of these congenitally infected newborn lambs (n=11) with toltrazuril (20mg/kg) on Day 1, 7, 14 and 21 was not effective as determined by serology, histopathology and qPCR. An avidity ELISA assay was able to differentiate between recently and chronically infected sheep. A longitudinal study with serology on 3 farms where N. caninum infected sheep were previously identified, found an overall seroprevalence of 0.8% (n=7/880) for N. caninum antibodies. The low seroprevalence observed across selected farms did not allow a meaningful interpretation to be made about the role of neosporosis on these farms. A consistent observation was the value of using multiple diagnostic tests to detect the presence of Neospora rather than relying exclusively on any one of them. Observation of typical lesions was generally more rewarding then the detection of Neospora DNA. Overall, further work is required to fully determine if N. caninum is causing reproductive problems in sheep in New Zealand.

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  • The role of career development in relation to the developmental contextual position of young people in New Zealand : considerations for policy development and career services in New Zealand secondary schools : thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Education

    McIntyre, Diana J (1998)

    Doctoral thesis
    Massey University

    This is a study of young peoples' career development needs and awareness and the relationship to personal development at the interface of school provision and wider economic, political and educational change that impinge on those relationships. It is theoretically embedded within the developmental contextual position of adolescent development, but much of the study is concerned with generating a comprehensive data base to inform policy development and practice considerations in careers assistance in New Zealand secondary schools. It begins, therefore, with an overview of the analytical framework of developmental contextualism, and goes on to explore more fully the dimensions presumed to be operating in relation to the career development of New Zealand youth. In doing so, it contributes a multidisciplinarian perspective, the essence of which it is argued, is an integral and necessary consideration in the provision of a developmentally appropriate and socially accountable approach to careers services in secondary schools. An examination of senior secondary school students' career development characteristics and experiences to which schools are in a position to respond forms the central empirical study of the latter part of this thesis. School careers staff, parents' and students' believed that schools were important environments for young people's career exploration and development and that an integrated, comprehensive careers service was an acceptable responsibility of secondary schooling. The careers information bases in schools were considered to be well resourced. Other dimensions, including career education, career advice and career counselling were nominated the most crucial areas needed for improvement. Limited opportunity for professional development and training in careers work was considered by staff to be the greatest barrier toward the provision of developmentally appropriate careers assistance. Other barriers included limited time allocation for careers work, low status in the school and unclear specifications regarding the role of careers staff and career services. Parents did not feel adequately informed about the nature and role of careers assistance in schools and this was considered a hindrance toward constructive involvement with their childrens career development. For the majority of students concern around career-related issues represented the source of considerable anxiety in their life. Careers assistance was highly valued by these young people, with most expressing concern about access to good quality careers advice and careers counselling. Limited access to specialised assistance at the personal level was reflected by students self reports on measures of career development and personal coping resources. Generally, the young people reported that they had not engaged adequately in appropriate career planning activities; had few 'useful' career exploration experiences; possessed insufficient knowledge about the nature and requirements of the world of work or occupations; and were not particularly knowledgeable about what to consider in making career-related (including education, training and work) decisions. Statistically significant relationships were found between scores on indices of career development and scores on a measure of how students coped with career-related concerns. While most young people approached career problems constructively, those students who were less likely to have engaged in useful planning and exploration and who had limited knowledge of the world of work generally were more likely to approach career development concerns non-productively, such as worrying about what might happen or closing oneself off from the problem. Perhaps the most salient theme to emerge in this thesis is the conviction that the career development of young people is a social as well as a personal process. Both the individual and society have much to gain from the young person's capacity for realism and purpose concerning school and post-school pathways and ultimately in the possession of a beginning repertoire of personal resources to manage career transitions in future journeys during their adult years. Ultimately, the complex interaction of individuals and society in relation to career pathways demand school-based career services which are clearly defined in policy, operationalised in official documentation, adequately resourced in relation to personnel and training and properly integrated alongside existing school practices.

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  • Investigation of dothistroma needle blight development on Pinus radiata : a thesis presented in the partial fulfilment of the requirements for the degree of Doctor of Philosophy (PhD) in Microbiology and Genetics at Massey University, Manawatu, New Zealand

    Kabir, Md Shahjahan (2014)

    Doctoral thesis
    Massey University

    Dothistroma needle blight (DNB), caused by the fungi Dothistroma septosporum and Dothistroma pini, is an important foliar disease of pine species throughout the world and predictions of the future spread of this disease have been made using climate models. Although DNB infection is prevalent in many forests, attempts to achieve infection under controlled laboratory or glasshouse conditions are notoriously difficult. However, artificial infection is a very important tool for studying different aspects of plant-microbe interactions, such as pathogen life style and roles of virulence factors. D. septosporum was thought to have a hemi-biotrophic life style but this was not formally investigated in planta. The non-host selective toxin dothistromin produced by this fungus was shown not to be essential for pathogenicity but its role in pathogen virulence was unknown. The aims of this study were to improve the DNB pathogenicity assay and to use this system to test the hypotheses that D. septosporum is a hemi-biotrophic pathogen and that dothistromin plays a role in virulence. A new sporulation medium (pine needle medium with glucose) was used to obtain sufficient viable D. septosporum spores. The critical microclimatic component of leaf wetness was optimised to have a short (4-7 d) high wetness period followed by 'medium' wetness (continual misting), and using these conditions >80% needle infection was routinely achieved on Pinus radiata seedlings. A combination of microscopy, biochemical and molecular studies over a timecourse of infection of P. radiata by D. septosporum confirmed its hemi-biotrophic life style. Restricted mesophyll colonisation, shorter lesions and fewer spores from P. radiata needles infected with dothistromin-deficient mutants, compared to those with wild type D. septosporum, suggested that dothistromin has a role in virulence. Interestingly ‘green islands’ in which chlorophyll levels were maintained at higher levels than adjacent chlorotic and necrotic regions, surrounded early-appearing lesions caused by both wild-type and mutant isolates. At a later developmental stage of the lesion the green islands were still present in the mutant but appeared to be masked by the extended dothistromin-containing lesions in the wild type, which lead to the hypothesis that chloroplasts could be a site of action of dothistromin. The discovery that dothistromin is a virulence factor opens up new insights into the Dothistroma-pine interaction. This fundamental finding will be useful for management strategies for this important disease in the future.

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  • Malignant lymphomas in sheep : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University

    Johnstone, Alastair Campbell (1974)

    Doctoral thesis
    Massey University

    Malignant lymphoma is the general term applied to any neoplastic disorder of lymphoid tissue, including Hodgkin's disease and reticulum cell sarcoma. This group of neoplasms are among the most commonly occurring spontaneous neoplasms of sheep in New Zealand, being exceeded in frequency only by carcinomas of the small intestine and primary neoplasms of the liver. It has not been established whether malignant lymphoma is of sporadic or enzootic occurrence in this country, but from limited epidemiological observations in which on two occasions the disease was seen in two animals from the same property, it is possible that the latter distribution occurs. This and most other series indicate that mature sheep are most frequently affected but the disease does occur in younger sheep and lambs. A study has been made of the pathology of ovine malignant lymphoma, based on 22 cases, most of which were collected from slaughter-houses and histological material from a further 18 cases filed previously at this laboratory. In nearly all cases nodular or diffuse lesions, consisting of accumulations of invasive neoplastic cells of lymphoid origin, were distributed widely throughout the body. Gross evidence of tumour in the lymph nodes was present in all except three cases of the disease. This involvement was usually multiple, with many of the carcass and visceral lymph nodes containing tumours. The spleen contained neoplastic lesions in 73 per cent. of the cases examined. Of the non-lymphoid organs affected by malignant lymphoma, the liver, kidney, bone marrow, heart, small intestine and abomasum predominated. Of the 40 cases examined, 37 were classified as lymphosarcomas and three as reticulum cell sarcomas. The degree of cellular differentiation in the lymphosarcomas varied from primitive lymphoblastoid to well differentiated lymphocytic cell types, with the less differentiated forms being more common. Some nuclear and cytoplasmic abnormalities which have previously been described as being non-specific in other types of neoplasms were seen in specimens from 10 cases which were examined with an electron microscope. Support for the hypothesis that "malignant lymphoma of sheep is transmissible" was sought by attempts to experimentally transmit this disease to lambs using intraperitoneal injections of cell-free tumour extracts during gestation or within 12 hr of birth. To date none of these sheep, which are only three years old, have developed overt neoplasia but 20 of them have developed elevated numbers of circulating lymphocytes. This has persisted for periods of two years or more and there is evidence to indicate that this should be interpreted as a preclinical phase of malignant lymphoma. To investigate an hypothesis that malignant lymphoma of sheep is due to infection by an oncorna virus, electron microscopic examinations were made on specimens from fresh tumour as well as on preparations from tissue cultures which had been inoculated with various ovine lymphoid tumour homogenates. These studies were inconclusive and it was not until cultures of phytohaemagglutinin-stimulated lymphocytes derived from the sheep with experimentally transmitted lymphocytosis were examined that virus-like particles, consistent with the morphology of "type-A" oncorna viruses could be demonstrated. They were present in membrane-limited vacuoles and cytoplasm of these cells and less frequently extra-cellularly in the five experimentally inoculated sheep examined but were not present in any of the lymphocytes from an equal number of control sheep. Lymphocyte cultures from 15 of the experimentally inoculated sheep showed sensitization to antigens in ovine malignant lymphoma homogenates when tested by a macrophage migration inhibition test. This test also demonstrated the presence of common tumour specific antigens in five of the six tumour extracts used either for sheep inoculations or in testing for macrophage inhibitory factor production. In an attempt to accelerate the development of overt neoplasia in three of the experimentally inoculated animals showing a persistent lymphocytosis, they were given a combined course of the immunosuppressive agents azathioprine and horse anti-sheep lymphocyte globulin. This resulted in a profound fall in circulating lymphocytes and while the cell mediated immunity was suppressed, as judged by the survival of skin allografts, macrophage migration inhibition in response to tumour antigens was not significantly altered in two of the three animals under treatment. A close relationship was demonstrated in the experimentally inoculated sheep between the occurrence of lymphocytosis, the development of tumour specific cell mediated immunity and the presence of virus-like particles in phytohaemagglutinin-stimulated lymphocytes. This evidence combined with the demonstration of common apparently tumour specific antigens in malignant lymphoma extracts used in these studies provides strong support for the hypothesis"that this disease of sheep is transmissible and is most probably due to an infection with an oncogenic virus". The exploitation of the sheep model described is of potential value for the comparative study of preneoplastic events in the general field of cancer research.

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  • Behaviour of emulsion gels in the human mouth and simulated gastrointestinal tract : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, Manawatu, New Zealand

    Guo, Qing (2015)

    Doctoral thesis
    Massey University

    Food structure greatly impacts the digestion process of food in the human body. Food structure design is a potential strategy to modulate food digestion and develop foods with controlled nutrient digestion and release. This research aimed to understand the dynamic processes of digestion of whey protein emulsion gels from the mouth to the intestine. Therefore, a series of heat-set whey protein emulsion gels, the structure of which was designed by varying NaCl concentration (10, 25, 100 and 200 mM) and oil droplet size (1, 6 and 12 µm), were formed. Mechanical properties in linear viscoelastic region, large deformation and fracture region and microstructure of gels were evaluated. In vivo oral processing and in vitro oral-to-gastrointestinal digestion of whey protein emulsion gels with different structures were investigated with a focus on the effect of gel structure on the gel disintegration and lipid digestion. Results showed that the gel strength increased with increasing NaCl concentration. At the micro-scale, the gel structure became from homogenous to porous with increasing NaCl concentration from 10 to 200 mM. The fragmentation degree of whey protein emulsion gels in the mouth showed a positive linear relationship with the gel strength (i.e. a higher gel strength, the greater gel fragmentation degree). During oral processing, the small oil droplets (~ 0.45 µm) incorporated in the protein matrix were stable without oil droplet release. During gastric digestion, the bolus of the gel containing 10 mM NaCl (soft gel) disintegrated much faster than that of the gel containing 200 mM NaCl (hard gel) in the human gastric simulator (HGS). The disintegration of the soft gel in the HGS was caused by both the abrasion and fragmentation while the abrasion was the predominant mechanism of the disintegration of the hard gel. The larger particle size of the soft gel bolus slowed down the emptying of gels from the HGS. With continued digestion, the emptying of both gels from the HGS was accelerated by gel disintegration. The gel structure greatly influenced the gel disintegration at the micro-scale. The soft gel particles were gradually disrupted into individual oil droplets, with the protein matrix dissolving after gastric digestion for 4 hours while the hard gel particles still retained the oil droplets inside the protein matrix. The colloidal structure of emptied gastric digesta, which generated from original gel structure, still significantly impacted the digestion of whey protein emulsion gels in an in vitro intestinal model. In general, the colloidal structure of the emptied gastric digesta of the hard gel hindered the breakdown of gel particles and hydrolysis of oil droplets more effectively than that of the soft gel. The remaining structure within the hard gel particles limited the free motion of oil droplets, which led to a lower degree of coalescence and breakup of oil droplets. Interestingly, coalescence appeared to occur between neighboring oil droplets inside the emptied gastric digesta of the hard gel during intestinal digestion. The structure of the gels containing 100 mM NaCl became from aggregated particle to emulsion-filled with increasing oil droplet size from 1 to 12 µm. The gel strength also decreased with the increase of droplet size. For the gels containing large oil droplets (6 and 12 µm), oil droplets were released from the protein matrix along with some coalescence during oral processing. During gastric digestion, a higher degree of coalescence of oil droplets occurred and coalesced oil droplets creamed to form a top oil layer. This slowed down the emptying of gels from the HGS. For the gels containing 1 µm oil droplets, most oil droplets still retained in the protein matrix during oral and gastric digestion with minimal instability of oil droplets. In addition, increasing interactions between oil droplets and protein matrix by decreasing oil droplet size hindered the protein hydrolysis. Overall, this research provides an understanding of the way in which food disintegrates in the human body and highlights the role of food structure on the digestion of food in the human body. These findings could assist in designing the functional new foods that deliver health benefits (e.g. lipid regulation, encapsulation and release of nutrients) and improving human health related to food digestion (e.g. dysphagia, dyspepsia).

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  • Estimating the public health risk associated with drinking water in New Zealand : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Masey University

    Phiri, Bernard Joakim (2015)

    Doctoral thesis
    Massey University

    This thesis is concerned with the application of both epidemiological and molecular tools to assess the drinking water safety in New Zealand. Compromised drinking water safety is commonly manifested as gastrointestinal illness. The studies in this thesis were motivated by the desire to nd ways of reducing the burden of such illness in the human population. Although the studies were conducted in the New Zealand setting the methodologies can be readily applied elsewhere. The rst study investigated the factors associated with the presence of microbes in raw water intended for public consumption. Random forest, an established non-parametric statistical method, was used to model data with possible complex interactions and identi ed variables that were predictive of the presence of microbes in raw drinking water. E. coli, which is widely used as a microbial contamination indicator in the water industry, was found to be a better predictor of the presence/absence of Campylobacter (bacteria) than protozoan microbes (Cryptosporidium and Giardia). This suggests that alternative methods of determining the presence/absence of pathogens in water should be developed. In the second study, the relationship between river ow and reports of cases of gastrointestinal illness was described using the distributed lag modelling approach. This revealed a positive relationship that peaked around 10 days after high ow. Further, the river ow-gastrointestinal illness relationship was stronger in small drinking distribution networks than in large ones. The small drinking water distribution networks could be targetted for facility upgrade in order to enhance their ability to deliver microbiologically safer drinking water. The third study utilised culture-dependent methods to assess the public health risk associated with drinking water supplied at outdoor recreation facilities | campgrounds. Water treatment using methods such as ultra violet and chemical treatment were found to be highly bene cial for the campgrounds to deliver drinking water that was microbiologically safe and compliant with water safety regulations. The pro les and functional factors of drinking water microbial communities are described in the fourth study. Techniques from the fast-growing eld of metagenomics were employed for this purpose. The capability of metagenomic techniques to detect multiple pathogens in a single assay was demonstrated. This has the potential to greatly enhance the speci city and sensitivity of microbial water quality testing.

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  • Effects of postharvest treatments on sweetpotato (Ipomoea batatas) storage quality : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, New Zealand

    Pankomera, Pilirani (2015)

    Doctoral thesis
    Massey University

    After harvest, sweetpotato (Ipomoea batatas) storage root quality is reduced due to weight loss, sprouting and rots. There are also hidden quality losses relating to loss of nutritional compounds. In order to maintain sweetpotato quality during storage, sweetpotatoes need to be stored at 13 - 15 °C and 80 - 90% RH. However, controlled temperature methods are difficult to achieve for subsistence farmers in less developed countries who have limited access to electric power. This work was undertaken to determine the potential postharvest techniques that would extend sweetpotato storage life without compromising phytochemical concentration. Postharvest treatments investigated in this work were hot water dipping (with or without coating) and ethylene (with or without 1-MCP) treatments. The work was undertaken using mainly ‘Owairaka Red’ and ‘Clone 1820’ sweetpotato cultivars. Following treatments, these sweetpotatoes were stored at 25 °C and 80 - 90% RH for 4 to 12 weeks. Hot water dipping (HWD) at 51 °C for 11 min delayed sprout growth by 2 weeks but increased weight loss. Coating (carnauba wax 5%) significantly reduced weight loss, but increased sprout growth in ‘Owairaka Red’. A combination of HWD and coating was effective in reducing both sprout growth and weight loss. ß-carotene content measured in ‘Clone 1820’ ranged from 17.3 to 25.6 mg/100 g dry weight. The concentration was not affected by HWD or coating, but declined by about 30% during 12 weeks storage. The calculated retinol activity equivalent (RAE) ranged from 363 to 537 RAE, per 100 g of edible portion of sweetpotato. Based on the recommended daily intake for vitamin A, a serve of 100 g would supply more than 25% of daily retinol requirement for all age groups, suggesting that even after storage ‘Clone 1820’ is a good source of vitamin A. In addition, no treatment adversely affected the phenolic acid and anthocyanin concentrations. Roots that were HWD showed a subtle increase in total phenolic content, phenolic acids and anthocyanin concentration when compared to control roots, but the effect was shortlived. Previous studies have demonstrated that ethylene is a potential sprout inhibitor, but causes darkening of flesh colour and the development of off-flavours after cooking. Ethylene-induced responses may be inhibited by 1-methylcyclopropene (1-MCP). 1- MCP and ethylene combined effects on sweetpotato physiological, flesh colour and phytochemical variables were assessed during storage. Ethylene treatment with or without 1-MCP inhibited sprout growth, increased root respiration rates by 2-fold, and caused root stem-end split leading to high weight loss and rots. Ethylene treatments also caused flesh darkening, and this was not prevented by a single 1- MCP (1 µL L-1) pre-storage treatment. When roots stored in continuous ethylene were subjected to multiple 1-MCP (1 µL L-1) treatments, the ethylene-induced root splitting and flesh darkening were delayed/reduced whilst maintaining minimal sprout growth. This implies that ethylene-induced negative responses in sweetpotato can be mitigated with on-going 1-MCP treatment. The sensory results showed that roots stored in air were highly preferred by consumers over roots stored in ethylene; nevertheless, acceptance means scores of all treatments were above five, indicating that ethylene-induced flesh darkening was not severe enough to cause consumer rejection. Based on these findings, it is proposed that a combination of HWD and coatings can be used to extend non-refrigerated storage life of sweetpotato with no major effect on phytochemical content. The results on ethylene are consistent with previous findings that ethylene suppresses sprout elongation. However, the associated negative effects outweigh the benefits of using ethylene as a sprout control. Future research therefore should focus on finding ways to get the benefit of ethylene for sprout reduction without incurring risk of root splitting.

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