title: Mass Spectral Characterisation of Three New Groups  of Algal Toxins

authors: Knudsen, Brent Kevin

subjects: pectenotoxin

abstract: This thesis reports the mass spectral identification and characterisation of three new groups of algal compounds.

A series of novel pectenotoxins (PTXs) were identified in retained sub-samples of Irish mussel extracts that had previously been utilised to obtain bulk quantities of some other algal toxins. The first eluting of the novel pectenotoxins, when analysed on a C-18 column using an MeCN-H2O gradient, afforded MNH4+ and MNa+ ions at m/z 864 and 869 respectively. This compound was designated as PTX-i. Three minor isomers (possibly storage artefacts) of the dominant PTX-i compound were also detected in the retained extracts, together with several later eluting sulfonated and sulfonated fatty acid ester analogues of PTX-i. The dominant fatty acid analogues were found to be the 16:0 esters. Sulfonated PTX-i isomers and their 16:0 fatty acid ester analogues showed strong m/z 925 and 1163 ion responses respectively in negative ion mode. High resolution mass spectrometry (HRMS) data showed the atomic composition of the m/z 925 ion to be C47H69O17S. Full scan, MS2, MS3 and MS4 mass spectral data determined in both positive and negative ion modes for the three series of PTX-i compounds was consistent with the proposal that they possessed a C5H11O3 side chain attached to C-35, rather than a 36-hemiacetal ring system as found in other known pectenotoxins, and that the sulfate and fatty acid residues were attached to two of the hydroxyl groups believed to present in the C5H11O3 side chain.

An algal water sample collected from Vigo, Spain (Dinophysis acuta, 12/12/05), that had previously been extracted with CH2Cl2 and Et2O, was found to contain low levels of two new pectenotoxin-2 seco acid (PTX-2SA) analogues that showed MNH4+ and MNa+ ions at m/z 896 and 901 respectively. Full scan, MS2, MS3 and MS4 mass spectral data determined in positive ion mode, in combination with NaBH4 and NaBD4 reduction reaction product data determined for PTX-2SA and the two new compounds, established that the new compounds were 14-hydroxy analogues of PTX-2SA.
The Spanish algal water sample also found to contain an appreciable level of two glycosides which were identified from a combination of full scan, MS2, MS3 and MS4 mass spectral data determined in both positive and negative ion modes as either 7- or 24-O-glycosides of okadaic acid (OA) and dinophysistoxin-2 (DTX-2), as MSn data excluded C-2 or C-27 O-glycosylation. 1D and 2D-1H NMR, obtained by co-workers while the mass spectral investigations reported in this thesis were in progress, showed that the glycosides were the 24-β-O-glucopyranosyl analogues of OA and DTX-2.

A set of three New Zealand derived algal water extracts, two from West Coast, South Island (Dinophysis acuta) and one from Akaroa Harbour (Dinophysis acuminata), were prepared and analysed for the three groups of new algal compounds reported in this thesis. PTX-i and its analogues were not detected in any of the New Zealand samples, the two 14-hydroxy PTX-2SA compounds were detected in one of the West Coast samples and the Akaroa Harbour samples and 24-O-glucoside OA and DTX-2 analogues were only detected in the Akaroa Harbour sample.

text: Mass Spectral Characterisation of Three New Groups  of Algal Toxins This thesis reports the mass spectral identification and characterisation of three new groups of algal compounds.

A series of novel pectenotoxins (PTXs) were identified in retained sub-samples of Irish mussel extracts that had previously been utilised to obtain bulk quantities of some other algal toxins. The first eluting of the novel pectenotoxins, when analysed on a C-18 column using an MeCN-H2O gradient, afforded MNH4+ and MNa+ ions at m/z 864 and 869 respectively. This compound was designated as PTX-i. Three minor isomers (possibly storage artefacts) of the dominant PTX-i compound were also detected in the retained extracts, together with several later eluting sulfonated and sulfonated fatty acid ester analogues of PTX-i. The dominant fatty acid analogues were found to be the 16:0 esters. Sulfonated PTX-i isomers and their 16:0 fatty acid ester analogues showed strong m/z 925 and 1163 ion responses respectively in negative ion mode. High resolution mass spectrometry (HRMS) data showed the atomic composition of the m/z 925 ion to be C47H69O17S. Full scan, MS2, MS3 and MS4 mass spectral data determined in both positive and negative ion modes for the three series of PTX-i compounds was consistent with the proposal that they possessed a C5H11O3 side chain attached to C-35, rather than a 36-hemiacetal ring system as found in other known pectenotoxins, and that the sulfate and fatty acid residues were attached to two of the hydroxyl groups believed to present in the C5H11O3 side chain.

An algal water sample collected from Vigo, Spain (Dinophysis acuta, 12/12/05), that had previously been extracted with CH2Cl2 and Et2O, was found to contain low levels of two new pectenotoxin-2 seco acid (PTX-2SA) analogues that showed MNH4+ and MNa+ ions at m/z 896 and 901 respectively. Full scan, MS2, MS3 and MS4 mass spectral data determined in positive ion mode, in combination with NaBH4 and NaBD4 reduction reaction product data determined for PTX-2SA and the two new compounds, established that the new compounds were 14-hydroxy analogues of PTX-2SA.
The Spanish algal water sample also found to contain an appreciable level of two glycosides which were identified from a combination of full scan, MS2, MS3 and MS4 mass spectral data determined in both positive and negative ion modes as either 7- or 24-O-glycosides of okadaic acid (OA) and dinophysistoxin-2 (DTX-2), as MSn data excluded C-2 or C-27 O-glycosylation. 1D and 2D-1H NMR, obtained by co-workers while the mass spectral investigations reported in this thesis were in progress, showed that the glycosides were the 24-β-O-glucopyranosyl analogues of OA and DTX-2.

A set of three New Zealand derived algal water extracts, two from West Coast, South Island (Dinophysis acuta) and one from Akaroa Harbour (Dinophysis acuminata), were prepared and analysed for the three groups of new algal compounds reported in this thesis. PTX-i and its analogues were not detected in any of the New Zealand samples, the two 14-hydroxy PTX-2SA compounds were detected in one of the West Coast samples and the Akaroa Harbour samples and 24-O-glucoside OA and DTX-2 analogues were only detected in the Akaroa Harbour sample.

year: 2009

title: Why we're seduced by climate tech and what it means for our happiness

authors: Weijers, Dan M.

abstract: For the most climate-anxious among us, it may even seem best to succumb to the climate tech horizon bias because of the short-term happiness benefits. However, recent research and personal experience are increasingly revealing that the climate catastrophe has already begun. Severe weather events, sea-level rise, and record-breaking heatwaves are impacting millions of people around the world, and doing so with increasing frequency (IPCC, 2023). In the face of this overwhelming evidence, nearly everyone (that doesn't already) should realize that climate tech is not a complete solution to the climate crisis. For those so in the grip of the climate tech horizon bias that they haven't done anything to help address climate change, the happiness impacts of being exposed to extreme weather events and other climate-change-related harms (Clayton, 2020) will include the extra sting of realizing that they had been seduced by the easy solace offered by over-hyped climate tech, and that they could have done more to prevent this affront to their and others' happiness.

Human selfishness, weakness of will, and uncritical thinking are the root problems. Climate tech is part of the solution but, thanks to the horizon bias, may exacerbate the climate problem and cause unhappiness if it is relied upon too heavily. Given the current climate crisis, some unhappiness seems unavoidable. In our view, the best solution is to keep acting in climate friendly ways as individuals, which includes joining with others to encourage governments and businesses to take immediate large-scale steps to reduce emissions as well as mitigate the ongoing effects of historical emissions. Schwartz et al. (2022) found that collective climate action seemed the most likely way to prevent climate anxiety turning into depression, plausibly because it alleviates feelings of individual powerlessness. Perhaps even more importantly, collective climate action may be necessary to prevent a future marred with many climate catastrophes (Gonzalez-Perez and Piedrahita-Carvajal, 2022) and the widespread unhappiness they would cause. So while we should empower promising climate tech by investing in it, we should also empower ourselves by joining with others and pushing for immediate emissions reductions. If we're right, this will make us happier individually and collectively, especially in the medium- and long-run.

text: Why we're seduced by climate tech and what it means for our happiness For the most climate-anxious among us, it may even seem best to succumb to the climate tech horizon bias because of the short-term happiness benefits. However, recent research and personal experience are increasingly revealing that the climate catastrophe has already begun. Severe weather events, sea-level rise, and record-breaking heatwaves are impacting millions of people around the world, and doing so with increasing frequency (IPCC, 2023). In the face of this overwhelming evidence, nearly everyone (that doesn't already) should realize that climate tech is not a complete solution to the climate crisis. For those so in the grip of the climate tech horizon bias that they haven't done anything to help address climate change, the happiness impacts of being exposed to extreme weather events and other climate-change-related harms (Clayton, 2020) will include the extra sting of realizing that they had been seduced by the easy solace offered by over-hyped climate tech, and that they could have done more to prevent this affront to their and others' happiness.

Human selfishness, weakness of will, and uncritical thinking are the root problems. Climate tech is part of the solution but, thanks to the horizon bias, may exacerbate the climate problem and cause unhappiness if it is relied upon too heavily. Given the current climate crisis, some unhappiness seems unavoidable. In our view, the best solution is to keep acting in climate friendly ways as individuals, which includes joining with others to encourage governments and businesses to take immediate large-scale steps to reduce emissions as well as mitigate the ongoing effects of historical emissions. Schwartz et al. (2022) found that collective climate action seemed the most likely way to prevent climate anxiety turning into depression, plausibly because it alleviates feelings of individual powerlessness. Perhaps even more importantly, collective climate action may be necessary to prevent a future marred with many climate catastrophes (Gonzalez-Perez and Piedrahita-Carvajal, 2022) and the widespread unhappiness they would cause. So while we should empower promising climate tech by investing in it, we should also empower ourselves by joining with others and pushing for immediate emissions reductions. If we're right, this will make us happier individually and collectively, especially in the medium- and long-run.

year: 2023

title: Rethinking English in Māori-medium education

authors: Hill, Richard Kenneth

subjects: Māori-medium

abstract: English language instruction in New Zealand's Māori-medium schools is controversial, with many schools either excluding it from their curriculum or adopting a tokenistic approach. Yet, how Māori-medium educators can best support their students' academic English language growth is still an under-researched and unresolved question. This paper reports on a project involving the English language transition programmes of three Māori-medium primary schools. Interviews and observations of key personnel within these schools revealed the components of their programmes, their perceptions of the need for English transition education and the issues they were facing in implementing English language instruction. The project found a direct relationship between levels of student language attainment and the quantity and quality of exposure to English instruction. Where an English programme occupied a significant place in a school's timetable and was staffed by teachers knowledgeable about the learning needs of bilingual students and how best to attend to these, the result was higher literacy scores and more satisfied students. This paper argues that planning English language outcomes for Māori-medium students is essential if becoming biliterate is an important aim. This planning must also be long-term, across all 13 years of the students' education.

text: Rethinking English in Māori-medium education English language instruction in New Zealand's Māori-medium schools is controversial, with many schools either excluding it from their curriculum or adopting a tokenistic approach. Yet, how Māori-medium educators can best support their students' academic English language growth is still an under-researched and unresolved question. This paper reports on a project involving the English language transition programmes of three Māori-medium primary schools. Interviews and observations of key personnel within these schools revealed the components of their programmes, their perceptions of the need for English transition education and the issues they were facing in implementing English language instruction. The project found a direct relationship between levels of student language attainment and the quantity and quality of exposure to English instruction. Where an English programme occupied a significant place in a school's timetable and was staffed by teachers knowledgeable about the learning needs of bilingual students and how best to attend to these, the result was higher literacy scores and more satisfied students. This paper argues that planning English language outcomes for Māori-medium students is essential if becoming biliterate is an important aim. This planning must also be long-term, across all 13 years of the students' education.

year: 2011