title: Widespread distribution and identification of eight novel microcystins in Antarctic cyanobacterial mats

authors: Wood, Susanna A.

subjects: biology

abstract: The microcystin content and cyanobacterial community structure of Antarctic microbial mat samples collected from 40 ponds, lakes and hydro-terrestrial environments were investigated.  Samples were collected from Bratina Island and four of the Dry Valleys; Wrights, Victoria, Miers and Marshall. Enzyme-linked immunosorbent assays (ELISA), liquid chromatography mass spectrometry (LC-MS), and protein phosphatase inhibition assays (PP-2A) resulted in the identification of low levels (1 - 16 mg/kg dry weight) of microcystins in all samples. A plot of indicative potencies of microcystins (ratio PP-2A:ELISA) versus total microcystins (ELISA) showed a general decrease in potency as total microcystin levels increased and a clustering of values from discrete geographic locations. LC-MS/MS analysis on selected samples identified eight novel microcystin congeners. The low energy collisional activation spectra were consistent with variants of [D-Asp3] MC-RR and [D-Asp3] MC-LR containing glycine [Gly1] rather than alanine and combinations of homoarginine [hAr2] or acetyldemethyl ADDA [ADMAdda5] substitutions. Nostoc sp. was identified as a microcystin producer using PCR amplification of a region of the 16S rRNA gene and the aminotransferase (AMT) domain of the mcyE gene. Automated ribosomal intergenic spacer analysis (ARISA) was undertaken to enable a comparison of cyanobacterial mat community structure from distant geographical locations. Two-dimensional multidimensional scaling ordination analysis of the ARISA data showed that in general samples from the same geographic location tended to clustered together.  ARISA also enabled the putative identification of the microcystin producing Nostoc sp. from multiple samples.

text: Widespread distribution and identification of eight novel microcystins in Antarctic cyanobacterial mats The microcystin content and cyanobacterial community structure of Antarctic microbial mat samples collected from 40 ponds, lakes and hydro-terrestrial environments were investigated.  Samples were collected from Bratina Island and four of the Dry Valleys; Wrights, Victoria, Miers and Marshall. Enzyme-linked immunosorbent assays (ELISA), liquid chromatography mass spectrometry (LC-MS), and protein phosphatase inhibition assays (PP-2A) resulted in the identification of low levels (1 - 16 mg/kg dry weight) of microcystins in all samples. A plot of indicative potencies of microcystins (ratio PP-2A:ELISA) versus total microcystins (ELISA) showed a general decrease in potency as total microcystin levels increased and a clustering of values from discrete geographic locations. LC-MS/MS analysis on selected samples identified eight novel microcystin congeners. The low energy collisional activation spectra were consistent with variants of [D-Asp3] MC-RR and [D-Asp3] MC-LR containing glycine [Gly1] rather than alanine and combinations of homoarginine [hAr2] or acetyldemethyl ADDA [ADMAdda5] substitutions. Nostoc sp. was identified as a microcystin producer using PCR amplification of a region of the 16S rRNA gene and the aminotransferase (AMT) domain of the mcyE gene. Automated ribosomal intergenic spacer analysis (ARISA) was undertaken to enable a comparison of cyanobacterial mat community structure from distant geographical locations. Two-dimensional multidimensional scaling ordination analysis of the ARISA data showed that in general samples from the same geographic location tended to clustered together.  ARISA also enabled the putative identification of the microcystin producing Nostoc sp. from multiple samples.

year: 2008

title: Isomerism of Complexes Containing Thiourea Dianion Ligands

authors: Spenceley, Jane Estelle

subjects: Thiourea

abstract: This thesis reports the synthesis and characterisation of eight new platinum thiourea complexes. Thiourea dianion complexes of the type (Ph₃P)₂PtSC(=NR)NPh, R=Me, Et, Prⁿ, Prⁱ, Buⁿ and (Ph₃P)₂PtSC(=NPh)NR R=Buͭ , p-tol, and the thiourea monoanion complex of the type [(Ph₃P)₂PtSC(=NEtH)NPh]⁺ were synthesised. This research confirms the prediction made by Henderson et al that asymmetrically substituted thiourea dianion complexes could form isomers. NMR studies show that the kinetically favoured isomer is formed initially, and then undergoes a solution phase isomerisation process to form the thermodynamically favoured isomer. Evidence that this isomerisation is affected by difference in substituent size and the energy difference between the two structures was obtained both experimentally, by use of NMR spectroscopy techniques, and theoretically using DFT calculations. Theoretically optimised geometries of each isomer allowed the calculation of ΔG(GPtrem-GPtadj) for each pair. NMR techniques were used to monitor the isomerisation process, which was clearly visible in both ¹H and ³¹P spectra. The relative substituent size, difference in energy between the two structures and rate of isomerisation appear to be proportional to each other. The greater the substituent size difference, the greater the difference in energy and faster the rate of isomerisation from the kinetically favoured isomer to the thermodynamically favoured isomer.

text: Isomerism of Complexes Containing Thiourea Dianion Ligands This thesis reports the synthesis and characterisation of eight new platinum thiourea complexes. Thiourea dianion complexes of the type (Ph₃P)₂PtSC(=NR)NPh, R=Me, Et, Prⁿ, Prⁱ, Buⁿ and (Ph₃P)₂PtSC(=NPh)NR R=Buͭ , p-tol, and the thiourea monoanion complex of the type [(Ph₃P)₂PtSC(=NEtH)NPh]⁺ were synthesised. This research confirms the prediction made by Henderson et al that asymmetrically substituted thiourea dianion complexes could form isomers. NMR studies show that the kinetically favoured isomer is formed initially, and then undergoes a solution phase isomerisation process to form the thermodynamically favoured isomer. Evidence that this isomerisation is affected by difference in substituent size and the energy difference between the two structures was obtained both experimentally, by use of NMR spectroscopy techniques, and theoretically using DFT calculations. Theoretically optimised geometries of each isomer allowed the calculation of ΔG(GPtrem-GPtadj) for each pair. NMR techniques were used to monitor the isomerisation process, which was clearly visible in both ¹H and ³¹P spectra. The relative substituent size, difference in energy between the two structures and rate of isomerisation appear to be proportional to each other. The greater the substituent size difference, the greater the difference in energy and faster the rate of isomerisation from the kinetically favoured isomer to the thermodynamically favoured isomer.

year: 2014

title: A Mana Wahine inquiry into indigenous governance

authors: Toi, Sharon Marjorie

subjects: Mana Wahine

abstract: This thesis investigates the question “How can indigenous women reinvigorate their role in tribal governance structures when many such structures continue to reinforce gendered colonial constructs within which women are marginalised?”  It is noted that contemporary tribal governance structures are often considered a site within which indigenous peoples can express cultural identity, however, when indigenous women are clearly under-represented in positions of power within those structures, this thesis questions why this situation continues. 
First, the thesis seeks to address the broad historical context within which indigenous women were subjected to colonial constructs of legislation, paternalistic government policies and the mechanisms of a euro-western court system policy. It is against this backdrop that comparisons are drawn that take into account the historical relationships between Māori, First Nations, Aboriginal, and Native American women and their respective colonising governments which bear alarming similarities in terms of the subjugation of these populations of women through colonisation. The significance of this historical-comparative lens is to illustrate how the status of women became seriously eroded within indigenous societies from traditional through to modern times. Consequently, this thesis goes on to explore the contemporary socio-political status of indigenous women as a result of their colonised history. 
From this broad historical context, the thesis narrows its view to examine commonalities and differences in relation to Māori and Native American women's experiences of tribal governance as tribal leaders and women of cultural significance and influence. The thesis changes tack to reflect the specific research intent of my Fulbright scholar experience to the University of Arizona, Tucson Arizona. Narrowing the focus of the research allowed me to analyse in more detail, beneficial comparisons of what was working for women tribal leaders under the auspices of the largely successful Native Nations Institute, Indigenous Governance Programme, in comparison to Māori women in tribal governance in Aotearoa, New Zealand. Importantly, this research synergises indigenous women’s shared knowledge in the reinvigoration of traditional tribal governance structures. The objective being to establish a body of knowledge that gives strength to a collective indigenous women's experience of governance from which normative propositions of indigenous governance based on western concepts can be examined, challenged and potentially transformed.  
It is noted that indigenous women have been included as essential decision-makers and leaders in traditional tribal governance systems; however, contemporary indigenous governance models do little to reflect this. The impact is that for indigenous women, tribal institutions and structures can themselves embed and reflect western colonial and patriarchal ideologies. Through our colonial experiences, indigenous peoples have inherited an oppressive gender legacy entrenched in policy and legislation that is socially constructed and instructed. To survive, indigenous women have to engage, challenge, resist and mitigate gendered spaces. This research highlights the extent to which indigenous women’s ways of leading or governing continue to be circumscribed in the on-going process of colonisation. Colonialism was a gendered process, and consequently, this thesis draws upon indigenous Feminist, Kaupapa Maori and Mana Wahine (Māori women’s) theoretical frameworks to analyse the complex ways that intersecting discourses of colonialism, race, gender and power continue to marginalise indigenous women within tribal governance. Indigenous Feminist theory also provides a framework for contextualising how First Nations, Aboriginal and Native American/American Indian women speak to these issues.  Importantly, how indigenous women are engaging in decolonising methodologies that impact the colonised practices, ways and attitudes they have or are currently experiencing in tribal governance, are also revealed.
Lastly, this thesis contributes to legal scholarship by contextualising the specific challenges of tribal governance for indigenous women. It addresses this by situating women’s experiences and ways of ‘being and doing’ within the micro tribal governance context while taking account of the macro realities of tribal governance politically, socially and more importantly, culturally.

text: A Mana Wahine inquiry into indigenous governance This thesis investigates the question “How can indigenous women reinvigorate their role in tribal governance structures when many such structures continue to reinforce gendered colonial constructs within which women are marginalised?”  It is noted that contemporary tribal governance structures are often considered a site within which indigenous peoples can express cultural identity, however, when indigenous women are clearly under-represented in positions of power within those structures, this thesis questions why this situation continues. 
First, the thesis seeks to address the broad historical context within which indigenous women were subjected to colonial constructs of legislation, paternalistic government policies and the mechanisms of a euro-western court system policy. It is against this backdrop that comparisons are drawn that take into account the historical relationships between Māori, First Nations, Aboriginal, and Native American women and their respective colonising governments which bear alarming similarities in terms of the subjugation of these populations of women through colonisation. The significance of this historical-comparative lens is to illustrate how the status of women became seriously eroded within indigenous societies from traditional through to modern times. Consequently, this thesis goes on to explore the contemporary socio-political status of indigenous women as a result of their colonised history. 
From this broad historical context, the thesis narrows its view to examine commonalities and differences in relation to Māori and Native American women's experiences of tribal governance as tribal leaders and women of cultural significance and influence. The thesis changes tack to reflect the specific research intent of my Fulbright scholar experience to the University of Arizona, Tucson Arizona. Narrowing the focus of the research allowed me to analyse in more detail, beneficial comparisons of what was working for women tribal leaders under the auspices of the largely successful Native Nations Institute, Indigenous Governance Programme, in comparison to Māori women in tribal governance in Aotearoa, New Zealand. Importantly, this research synergises indigenous women’s shared knowledge in the reinvigoration of traditional tribal governance structures. The objective being to establish a body of knowledge that gives strength to a collective indigenous women's experience of governance from which normative propositions of indigenous governance based on western concepts can be examined, challenged and potentially transformed.  
It is noted that indigenous women have been included as essential decision-makers and leaders in traditional tribal governance systems; however, contemporary indigenous governance models do little to reflect this. The impact is that for indigenous women, tribal institutions and structures can themselves embed and reflect western colonial and patriarchal ideologies. Through our colonial experiences, indigenous peoples have inherited an oppressive gender legacy entrenched in policy and legislation that is socially constructed and instructed. To survive, indigenous women have to engage, challenge, resist and mitigate gendered spaces. This research highlights the extent to which indigenous women’s ways of leading or governing continue to be circumscribed in the on-going process of colonisation. Colonialism was a gendered process, and consequently, this thesis draws upon indigenous Feminist, Kaupapa Maori and Mana Wahine (Māori women’s) theoretical frameworks to analyse the complex ways that intersecting discourses of colonialism, race, gender and power continue to marginalise indigenous women within tribal governance. Indigenous Feminist theory also provides a framework for contextualising how First Nations, Aboriginal and Native American/American Indian women speak to these issues.  Importantly, how indigenous women are engaging in decolonising methodologies that impact the colonised practices, ways and attitudes they have or are currently experiencing in tribal governance, are also revealed.
Lastly, this thesis contributes to legal scholarship by contextualising the specific challenges of tribal governance for indigenous women. It addresses this by situating women’s experiences and ways of ‘being and doing’ within the micro tribal governance context while taking account of the macro realities of tribal governance politically, socially and more importantly, culturally.

year: 2019