title: New esters of okadaic acid in seawater and blue mussels (Mytilus edulis)

authors: Torgersen, Trine

subjects: chemistry

abstract: Marine algal toxins of the okadaic acid (OA) group can occur as diol esters and sulfated diol esters in algae and as fatty acid esters in shellfish. Several of these ester forms have been identified, but the most common procedure for detecting OA group toxin esters is by measuring the increase in parent toxin after alkaline hydrolysis. Use of this alkaline hydrolysis method led to the discovery of high levels of conjugates of OA and dinophysistoxins-2 (DTX2) in seawater and of OA, DTX1, and DTX2 in blue mussel hepatopancreas (HP) from Flødevigen, Norway, during a bloom of Dinophysis spp. In the water sample, a C8-diol ester, a C9-diol ester, and a previously undescribed C8-triol ester of OA were characterized using HPLC-MS2, -MS3, and -MS4 in combination with various derivatization procedures. Palmitic acid (16:0) ester derivatives of these diol/triol esters were found in mussel HP and characterized using HPLC-MS2, -MS3, and -MS4. To the authors’ knowledge, hybrid diol-fatty acid esters of OA have not been previously described. Mass spectral analysis showed the presence of two forms of hybrid esters: one with the fatty acid conjugated to the 7-OH of the OA moiety and the other with the fatty acid conjugated to the OH group in the “diol” moiety. In the water sample, the C8-diol ester was the most abundant, whereas in the mussels, the 16:0-C9-diol hybrid ester was most abundant, and only minor amounts of the 16:0-C8-diol hybrid ester were detected, suggesting that C8- and C9-diol esters of OA may be metabolized differently in blue mussels. 7-O-acyl esters of OA, DTX1, and DTX2 are thought to contribute to shellfish toxicity by being hydrolyzed in the human stomach to the parent toxins, and the newly characterized hybrid esters are likely to contribute similarly.

text: New esters of okadaic acid in seawater and blue mussels (Mytilus edulis) Marine algal toxins of the okadaic acid (OA) group can occur as diol esters and sulfated diol esters in algae and as fatty acid esters in shellfish. Several of these ester forms have been identified, but the most common procedure for detecting OA group toxin esters is by measuring the increase in parent toxin after alkaline hydrolysis. Use of this alkaline hydrolysis method led to the discovery of high levels of conjugates of OA and dinophysistoxins-2 (DTX2) in seawater and of OA, DTX1, and DTX2 in blue mussel hepatopancreas (HP) from Flødevigen, Norway, during a bloom of Dinophysis spp. In the water sample, a C8-diol ester, a C9-diol ester, and a previously undescribed C8-triol ester of OA were characterized using HPLC-MS2, -MS3, and -MS4 in combination with various derivatization procedures. Palmitic acid (16:0) ester derivatives of these diol/triol esters were found in mussel HP and characterized using HPLC-MS2, -MS3, and -MS4. To the authors’ knowledge, hybrid diol-fatty acid esters of OA have not been previously described. Mass spectral analysis showed the presence of two forms of hybrid esters: one with the fatty acid conjugated to the 7-OH of the OA moiety and the other with the fatty acid conjugated to the OH group in the “diol” moiety. In the water sample, the C8-diol ester was the most abundant, whereas in the mussels, the 16:0-C9-diol hybrid ester was most abundant, and only minor amounts of the 16:0-C8-diol hybrid ester were detected, suggesting that C8- and C9-diol esters of OA may be metabolized differently in blue mussels. 7-O-acyl esters of OA, DTX1, and DTX2 are thought to contribute to shellfish toxicity by being hydrolyzed in the human stomach to the parent toxins, and the newly characterized hybrid esters are likely to contribute similarly.

year: 2008

title: Later life learning for adults in Scotland: tracking the engagement with and impact of learning for working-class men and women

authors: Findsen, Brian

subjects: education

abstract: Undertaken in the context of an ageing population and under-representation of older adults in formal education in Scotland, this paper reports on selected findings from research funded by the West of Scotland Wider Access Forum. Using a longitudinal design, the project sought, over a two-year period, to track the experiences of 85 working class older adults over the age of 50 in four further and three higher education institutions in the west of Scotland using four biannual semi-structured interviews. The authors examine learning engagement through the ‘lenses’ of gender and class, reporting thematically on the effects of these factors on engagement with, and motivation for, formal learning at the time of the study and throughout life. Related to gender, the authors report on how continuance with post-compulsory formal education was mitigated by culturally normative attitudes and practices, as well as more immediate pressing responsibilities or needs, and a reduced connection between accredited learning and employment. In the context of a ‘greying’ workforce that sees lesser engagement with formal learning as age increases, and difficulties for those with the least financial resource to undertake learning independently, the authors argue that greater investment in later life learning opportunities is necessary to maximise access and on-going participation.

text: Later life learning for adults in Scotland: tracking the engagement with and impact of learning for working-class men and women Undertaken in the context of an ageing population and under-representation of older adults in formal education in Scotland, this paper reports on selected findings from research funded by the West of Scotland Wider Access Forum. Using a longitudinal design, the project sought, over a two-year period, to track the experiences of 85 working class older adults over the age of 50 in four further and three higher education institutions in the west of Scotland using four biannual semi-structured interviews. The authors examine learning engagement through the ‘lenses’ of gender and class, reporting thematically on the effects of these factors on engagement with, and motivation for, formal learning at the time of the study and throughout life. Related to gender, the authors report on how continuance with post-compulsory formal education was mitigated by culturally normative attitudes and practices, as well as more immediate pressing responsibilities or needs, and a reduced connection between accredited learning and employment. In the context of a ‘greying’ workforce that sees lesser engagement with formal learning as age increases, and difficulties for those with the least financial resource to undertake learning independently, the authors argue that greater investment in later life learning opportunities is necessary to maximise access and on-going participation.

year: 2011

title: Tōku tūrangawaewae: Culture, identity, and belonging for Māori homeless people

authors: Groot, Shiloh Ann Maree

subjects: Māori

abstract: To be Māori is to have a tūrangawaewae (a place of strength and belonging, a place to stand). If so, is it conceivable that Māori are homeless in our own homeland? This presentation focuses on the experiences of two Māori homeless people who took part in a 3-year research project conducted in partnership with not-for-profit service agencies. Previous research into street homelessness has all but ignored indigenous histories, circumstances and worldviews. The situation in which indigenous people find themselves requires us to rethink how we understand homelessness and the development of culturally based roles and identities on the street and beyond.

text: Tōku tūrangawaewae: Culture, identity, and belonging for Māori homeless people To be Māori is to have a tūrangawaewae (a place of strength and belonging, a place to stand). If so, is it conceivable that Māori are homeless in our own homeland? This presentation focuses on the experiences of two Māori homeless people who took part in a 3-year research project conducted in partnership with not-for-profit service agencies. Previous research into street homelessness has all but ignored indigenous histories, circumstances and worldviews. The situation in which indigenous people find themselves requires us to rethink how we understand homelessness and the development of culturally based roles and identities on the street and beyond.

year: 2010