title: Investigation of Microcystin Processing, Production and Export by Microcystis sp.

authors: Rogers, Shelley

subjects: microcystin

abstract: During this study, the effect of different processing methods on the microcystin quota (microcystins per cell) was investigated.  Microcystins from two Microcystis strains and one Planktothrix strain were quantified using liquid chromatography-mass spectrometry (LC-MS) after processing via; (1) direct freezing (no prior cell concentration) and extraction by freeze-thaw cycles, (2) cell concentration by centrifugation and extraction in methanol and (3) cell concentration by filtration and extraction in methanol. Microcystin quotas were lower for samples concentrated by filtration compared with the other two methods.  

In order to distinguish between extracellular microcystins actively exported from cells and those that are present as a result of cell lysis, a comparative microcystin export (CME) assay was developed using LC-MS to compare the proportion of extracellular microcystins with the proportion of extracellular non-ribosomal peptide which does not get actively exported. A culture-based experiment using the CME assay demonstrated the utility of this method and indicated that export from one of the Microcystis strains had occurred. With further validation experiments, the CME assay has the potential to be a valuable new tool for determining the occurrence of microcystin export. 

An in situ experiment was carried out in Lake Rotorua, Kaikoura, New Zealand, using mesocosms to study the effect of Microcystis sp. cell density on microcystin production, while measuring a wide array of abiotic parameters (temperature, light intensity, pH, dissolved oxygen and nutrients). Lake water was added to ‘control’ mesocosms in which cells were concentrated to different levels and added to ‘medium cell addition’ and ‘high cell addition’ mesocosms. The microcystin quota remained relatively constant throughout the study, despite induced changes in cell density and associated environmental parameters. These results indicate that cell density is not the only factor responsible for increased microcystin synthesis and that further investigation into the effect of stress inducing abiotic parameters such as pH and dissolved oxygen concentration may be required.

text: Investigation of Microcystin Processing, Production and Export by Microcystis sp. During this study, the effect of different processing methods on the microcystin quota (microcystins per cell) was investigated.  Microcystins from two Microcystis strains and one Planktothrix strain were quantified using liquid chromatography-mass spectrometry (LC-MS) after processing via; (1) direct freezing (no prior cell concentration) and extraction by freeze-thaw cycles, (2) cell concentration by centrifugation and extraction in methanol and (3) cell concentration by filtration and extraction in methanol. Microcystin quotas were lower for samples concentrated by filtration compared with the other two methods.  

In order to distinguish between extracellular microcystins actively exported from cells and those that are present as a result of cell lysis, a comparative microcystin export (CME) assay was developed using LC-MS to compare the proportion of extracellular microcystins with the proportion of extracellular non-ribosomal peptide which does not get actively exported. A culture-based experiment using the CME assay demonstrated the utility of this method and indicated that export from one of the Microcystis strains had occurred. With further validation experiments, the CME assay has the potential to be a valuable new tool for determining the occurrence of microcystin export. 

An in situ experiment was carried out in Lake Rotorua, Kaikoura, New Zealand, using mesocosms to study the effect of Microcystis sp. cell density on microcystin production, while measuring a wide array of abiotic parameters (temperature, light intensity, pH, dissolved oxygen and nutrients). Lake water was added to ‘control’ mesocosms in which cells were concentrated to different levels and added to ‘medium cell addition’ and ‘high cell addition’ mesocosms. The microcystin quota remained relatively constant throughout the study, despite induced changes in cell density and associated environmental parameters. These results indicate that cell density is not the only factor responsible for increased microcystin synthesis and that further investigation into the effect of stress inducing abiotic parameters such as pH and dissolved oxygen concentration may be required.

year: 2014

title: Ripping yarns: Science in Asia

authors: Barker, Miles

subjects: Joseph Rock

abstract: The article explores the life and works of botanist Joseph Rock, historian Joseph Needham, and physicist J. C. Bose. Rock's expeditions and personality have become an enduring part of China's history which shows the notion that scientists participate in public affairs. Needham has embraced the documentation of the country's history of science and technology. Bose's infusion of three careers shows the notion that science is a blend of logic and imagination.

text: Ripping yarns: Science in Asia The article explores the life and works of botanist Joseph Rock, historian Joseph Needham, and physicist J. C. Bose. Rock's expeditions and personality have become an enduring part of China's history which shows the notion that scientists participate in public affairs. Needham has embraced the documentation of the country's history of science and technology. Bose's infusion of three careers shows the notion that science is a blend of logic and imagination.

year: 2010

title: Investigating Māori approaches to trauma informed care

authors: Pihama, Leonie

subjects: Māori health and wellbeing

abstract: This article gives an overview of a three-year Health Research Council funded research project “He Oranga Ngākau: Māori approaches to trauma-informed care”. The study is informed by Kaupapa Māori which provides both the theoretical and methodological foundation for understanding the world, exploring and conceptualising issues. The need for contextualised and culturally safe health and social services is well recognised within Aotearoa and particularly within Mental Health and Addiction Services. While trauma is an experience that can impact on all people, Māori experience trauma in distinct ways that are linked to the experience of colonisation, racism and discrimination, negative stereotyping and subsequent unequal rates of violence, poverty and ill health. Given that Māori are impacted by trauma in specific ways, it is important to explore and identify practice principles that contribute to the development of a framework that supports Māori Providers, counsellors, clinicians and healers in working with Māori. (Authors' abstract).

text: Investigating Māori approaches to trauma informed care This article gives an overview of a three-year Health Research Council funded research project “He Oranga Ngākau: Māori approaches to trauma-informed care”. The study is informed by Kaupapa Māori which provides both the theoretical and methodological foundation for understanding the world, exploring and conceptualising issues. The need for contextualised and culturally safe health and social services is well recognised within Aotearoa and particularly within Mental Health and Addiction Services. While trauma is an experience that can impact on all people, Māori experience trauma in distinct ways that are linked to the experience of colonisation, racism and discrimination, negative stereotyping and subsequent unequal rates of violence, poverty and ill health. Given that Māori are impacted by trauma in specific ways, it is important to explore and identify practice principles that contribute to the development of a framework that supports Māori Providers, counsellors, clinicians and healers in working with Māori. (Authors' abstract).

year: 2017