title: Semisynthesis of S-Desoxybrevetoxin-B2 and Brevetoxin-B2, and Assessment of Their Acute Toxicities

authors: Selwood, Andrew I.

subjects: chemistry

abstract: animals and people consuming seafood. Brevetoxin-B2 (5) is a toxic metabolite produced in shellfish exposed to algae that contain brevetoxin-B (1). S-Desoxybrevetoxin-B2 (4) has been proposed as a cometabolite produced during this transformation, and while LC-MS analyses suggest its presence in shellfish, it has not yet been isolated and characterized. Studies on these materials are severely constrained by the difficulty of obtaining and purifying them from natural sources. We have developed a convenient one-pot conversion of commercially available brevetoxin-B (1) into S-desoxybrevetoxin-B2 (4), and a simple method for converting 4 into brevetoxin-B2 (5). Full NMR and mass-spectral characterization of 4 and 5 confirmed their structures and showed that the ratio of diastereoisomers in the synthetic 4 and 5 was similar to that observed in naturally contaminated shellfish. The LD50 values for 4, 5, and dihydrobrevetoxin-B (6) by ip injection in mice were 211, 400, and 250 µg/kg, respectively. The methodology for synthesis of brevetoxin metabolites should greatly facilitate toxicological, biochemical and immunochemical studies of these substances, as well as the production of analytical standards.

text: Semisynthesis of S-Desoxybrevetoxin-B2 and Brevetoxin-B2, and Assessment of Their Acute Toxicities animals and people consuming seafood. Brevetoxin-B2 (5) is a toxic metabolite produced in shellfish exposed to algae that contain brevetoxin-B (1). S-Desoxybrevetoxin-B2 (4) has been proposed as a cometabolite produced during this transformation, and while LC-MS analyses suggest its presence in shellfish, it has not yet been isolated and characterized. Studies on these materials are severely constrained by the difficulty of obtaining and purifying them from natural sources. We have developed a convenient one-pot conversion of commercially available brevetoxin-B (1) into S-desoxybrevetoxin-B2 (4), and a simple method for converting 4 into brevetoxin-B2 (5). Full NMR and mass-spectral characterization of 4 and 5 confirmed their structures and showed that the ratio of diastereoisomers in the synthetic 4 and 5 was similar to that observed in naturally contaminated shellfish. The LD50 values for 4, 5, and dihydrobrevetoxin-B (6) by ip injection in mice were 211, 400, and 250 µg/kg, respectively. The methodology for synthesis of brevetoxin metabolites should greatly facilitate toxicological, biochemical and immunochemical studies of these substances, as well as the production of analytical standards.

year: 2008

title: The autecology of lonicera japonica in a restoration context

authors: Pudney, Kemble Jonathan

subjects: Lonicera japonica

abstract: This thesis concerns the autecology of Lonicera japonica in relation to ecological restoration in Hamilton. It addresses three groups of questions, relating to L. japonica's place in the plant community, its reproduction and spread, and its impacts on other plants. L. japonica's role in the plant communities of natural areas and restoration sites and its variation with environmental factors were studied quantitatively through vegetation measurement and soil analyses at plots established at a naturally regenerating site in Hamilton. Its role under varying disturbance regimes and physical conditions was studied qualitatively and semi-quantitatively at eight other locations. A simple model relating stem diameter to age was developed to assess the age and demography of L. japonica populations. L. japonica's potential to spread was assessed through trials to establish seed and fragment viability, examination of climatic records, and the identification from the literature of potential vectors. Impacts of L. japonica on other species were assessed first through a consideration of the frequency at which plants of differing characteristics are invaded, and second by characterising its impacts upon those plants. The thesis concludes with recommendations for further research and for the management of the plant in restoration areas.
Through the field work it was found that L. japonica is more widely dispersed both within and across natural areas and restoration sites in Hamilton than had been detected from initial site visits, to the extent that it was difficult to detect patterns and relationships at the chosen scale of investigation. It exhibits a tolerance for low pH and wet conditions greater than found in studies overseas, and neither those factors nor soil fertility are likely to limit its spread in restoration and natural areas in New Zealand. However at light levels found
ii
beneath typical native canopy cover the plant's vigour is greatly reduced, and this offers the most promising avenues for control. L. japonica disperses readily via stem fragments incorporating nodes and sets plentiful fertile seed. Though the viability of that seed is short, propagation by this means is possible in Hamilton and may become significant in relation to future restoration work. In good light conditions L. japonica forms dense mats that smother vegetation of low stature and prevent natural succession in canopy gaps, as well as compromising the health of restored areas. In locations with mature canopy L. japonica may survive over lengthy periods on the ground, with restricted vigour, or in canopy-entering clumps that have grown with the host; either form will expand rapidly if light conditions improve. However because of their growth form and trunk texture even mature tree ferns may be killed by L. japonica. Novel elements that have emerged from this study are the plant's tolerance of a wider range of environmental conditions in New Zealand than reported overseas, its potential to spread by seed in local conditions, and an emerging synergistic relationship with another invasive liane, Ipomoea indica. The latter two issues are worthy of further study.

text: The autecology of lonicera japonica in a restoration context This thesis concerns the autecology of Lonicera japonica in relation to ecological restoration in Hamilton. It addresses three groups of questions, relating to L. japonica's place in the plant community, its reproduction and spread, and its impacts on other plants. L. japonica's role in the plant communities of natural areas and restoration sites and its variation with environmental factors were studied quantitatively through vegetation measurement and soil analyses at plots established at a naturally regenerating site in Hamilton. Its role under varying disturbance regimes and physical conditions was studied qualitatively and semi-quantitatively at eight other locations. A simple model relating stem diameter to age was developed to assess the age and demography of L. japonica populations. L. japonica's potential to spread was assessed through trials to establish seed and fragment viability, examination of climatic records, and the identification from the literature of potential vectors. Impacts of L. japonica on other species were assessed first through a consideration of the frequency at which plants of differing characteristics are invaded, and second by characterising its impacts upon those plants. The thesis concludes with recommendations for further research and for the management of the plant in restoration areas.
Through the field work it was found that L. japonica is more widely dispersed both within and across natural areas and restoration sites in Hamilton than had been detected from initial site visits, to the extent that it was difficult to detect patterns and relationships at the chosen scale of investigation. It exhibits a tolerance for low pH and wet conditions greater than found in studies overseas, and neither those factors nor soil fertility are likely to limit its spread in restoration and natural areas in New Zealand. However at light levels found
ii
beneath typical native canopy cover the plant's vigour is greatly reduced, and this offers the most promising avenues for control. L. japonica disperses readily via stem fragments incorporating nodes and sets plentiful fertile seed. Though the viability of that seed is short, propagation by this means is possible in Hamilton and may become significant in relation to future restoration work. In good light conditions L. japonica forms dense mats that smother vegetation of low stature and prevent natural succession in canopy gaps, as well as compromising the health of restored areas. In locations with mature canopy L. japonica may survive over lengthy periods on the ground, with restricted vigour, or in canopy-entering clumps that have grown with the host; either form will expand rapidly if light conditions improve. However because of their growth form and trunk texture even mature tree ferns may be killed by L. japonica. Novel elements that have emerged from this study are the plant's tolerance of a wider range of environmental conditions in New Zealand than reported overseas, its potential to spread by seed in local conditions, and an emerging synergistic relationship with another invasive liane, Ipomoea indica. The latter two issues are worthy of further study.

year: 2009

title: Mai ngā reo pou tangata

authors: Nathan, Lisa Kiriwai

subjects: Maori

abstract: Globally the prevalence rate of dementia is estimated to be 50 million.  In 2016, Aotearoa New Zealand prevalence projections reported 62,287 people were affected by dementia.  Māori represented 5.1 per cent, which is expected to rise to 8 per cent by 2038.  Māori people prefer to care for ill kaumātua (older people) at home and are experiencing greater stress and increased caregiver burden due to the cultural expectations of caring for kaumātua at home.  The two aims of this study were first, to explore the perspectives of Māori whānau carers caring for kaumātua with dementia, and the second aim was to explore the perspectives of staff who work for dementia service providers, addressing areas such as staff’s experiences with Māori whānau carers and cultural competency in service delivery.
	Semi-structured interviews were conducted with eight whānau (11 whānau carers) within the Waikato region of New Zealand and seven service provider staff participants. Whānau carers were interviewed first.  They were asked to share information about their kaumātua.  The topics explored the diagnosis process; the behavioural changes of the kaumātua living with dementia and the whānau caring experience.  Thematic analysis was conducted on the resulting transcripts to identify themes and to identify potential service providers to approach for interviews.  Five service provider organisations were selected, of which four service providers were able to commit to an interview.  One service provider could not commit to an interview due to thesis time constraints. Seven staff participants across the four service providers were recruited and invited to share their perspectives of working with Māori whānau.  Again, thematic analysis was conducted on the verbatim transcripts to identify salient themes.
	Two major findings amidst the perspectives of whānau carers was identified.  First, the systemic lack of support across three dimensions, and second the negative impact of caregiver burden. The first deficiency was the lack of support from whānau members, second, the lack of support from community services and third, the lack of support from the government.  Whānau experienced poor health as a result of caregiver burden. Staff participants findings were firstly staff believed they were culturally inclusive and responsive, second they reported going beyond their roles and the system to support Māori and third staff identified barriers which exist for Māori in terms of accessing services.
	Whānau carers are struggling to find support from other whānau members.  Some whānau members are critical of caring methods, while others place additional burden on the carers.  Whānau are often described as an interconnected unit, however findings show that Māori whānau carers are feeling isolated and alone, and as a result are experiencing poor health. 
	Whānau carers perceive a services in their community as not being culturally inclusive or appropriate.  Staff participants said that they incorporate respect and compassion into their service delivery.  Staff recognise that the numbers of Māori represented at services are low, compared to non-Māori clients.  Services need to be integrate cultural training on a regular basis to ensure Māori are comfortable with being Māori in service settings.

text: Mai ngā reo pou tangata Globally the prevalence rate of dementia is estimated to be 50 million.  In 2016, Aotearoa New Zealand prevalence projections reported 62,287 people were affected by dementia.  Māori represented 5.1 per cent, which is expected to rise to 8 per cent by 2038.  Māori people prefer to care for ill kaumātua (older people) at home and are experiencing greater stress and increased caregiver burden due to the cultural expectations of caring for kaumātua at home.  The two aims of this study were first, to explore the perspectives of Māori whānau carers caring for kaumātua with dementia, and the second aim was to explore the perspectives of staff who work for dementia service providers, addressing areas such as staff’s experiences with Māori whānau carers and cultural competency in service delivery.
	Semi-structured interviews were conducted with eight whānau (11 whānau carers) within the Waikato region of New Zealand and seven service provider staff participants. Whānau carers were interviewed first.  They were asked to share information about their kaumātua.  The topics explored the diagnosis process; the behavioural changes of the kaumātua living with dementia and the whānau caring experience.  Thematic analysis was conducted on the resulting transcripts to identify themes and to identify potential service providers to approach for interviews.  Five service provider organisations were selected, of which four service providers were able to commit to an interview.  One service provider could not commit to an interview due to thesis time constraints. Seven staff participants across the four service providers were recruited and invited to share their perspectives of working with Māori whānau.  Again, thematic analysis was conducted on the verbatim transcripts to identify salient themes.
	Two major findings amidst the perspectives of whānau carers was identified.  First, the systemic lack of support across three dimensions, and second the negative impact of caregiver burden. The first deficiency was the lack of support from whānau members, second, the lack of support from community services and third, the lack of support from the government.  Whānau experienced poor health as a result of caregiver burden. Staff participants findings were firstly staff believed they were culturally inclusive and responsive, second they reported going beyond their roles and the system to support Māori and third staff identified barriers which exist for Māori in terms of accessing services.
	Whānau carers are struggling to find support from other whānau members.  Some whānau members are critical of caring methods, while others place additional burden on the carers.  Whānau are often described as an interconnected unit, however findings show that Māori whānau carers are feeling isolated and alone, and as a result are experiencing poor health. 
	Whānau carers perceive a services in their community as not being culturally inclusive or appropriate.  Staff participants said that they incorporate respect and compassion into their service delivery.  Staff recognise that the numbers of Māori represented at services are low, compared to non-Māori clients.  Services need to be integrate cultural training on a regular basis to ensure Māori are comfortable with being Māori in service settings.

year: 2019