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: Familiarity and Recollection in Everyday Driving

authors: James, Sarah Michelle

subjects: Everyday Driving

abstract: Driving a car is one of the most common activities that we take part in everyday, however previous research has indicated that there is a gap in our current knowledge about how familiarity affects our everyday driving behaviour. Many of the studies that examine everyday driving behaviours are conducted off-road through the use of driving simulators and self-report questionnaires. The objective of this present study was therefore to investigate the role of familiarity on everyday driving behaviours during on-road drives. Additionally, this thesis sought to to examine the relationship between familiarity and driver perceptions such as anxiety and risk. The relationship between familiarity and speed choices was also observed and finally, the impact of familiarity on a driver’s ability to recall important information about a drive was investigated. Data was collected through the use of video and self-report questionnaires. In total, 30 participants took took part in two on-road drives; one which they were familiar with and another that they found unfamiliar. Results indicated that speed choices were affected by how familiar a driver was with the environment, however no relationship was found between familiarity and driver perceptions of anxiety and risk, or recollection. Further research that builds on the present findings could prove to be beneficial for future approaches towards specific interventions aimed at reducing serious vehicle accidents.

text: Familiarity and Recollection in Everyday Driving Driving a car is one of the most common activities that we take part in everyday, however previous research has indicated that there is a gap in our current knowledge about how familiarity affects our everyday driving behaviour. Many of the studies that examine everyday driving behaviours are conducted off-road through the use of driving simulators and self-report questionnaires. The objective of this present study was therefore to investigate the role of familiarity on everyday driving behaviours during on-road drives. Additionally, this thesis sought to to examine the relationship between familiarity and driver perceptions such as anxiety and risk. The relationship between familiarity and speed choices was also observed and finally, the impact of familiarity on a driver’s ability to recall important information about a drive was investigated. Data was collected through the use of video and self-report questionnaires. In total, 30 participants took took part in two on-road drives; one which they were familiar with and another that they found unfamiliar. Results indicated that speed choices were affected by how familiar a driver was with the environment, however no relationship was found between familiarity and driver perceptions of anxiety and risk, or recollection. Further research that builds on the present findings could prove to be beneficial for future approaches towards specific interventions aimed at reducing serious vehicle accidents.

year: 2017

title: The physical health and premature mortality of Indigenous Māori following first-episode psychosis diagnosis: A 15-year follow-up study

authors: Monk, Nathan

subjects: First-episode psychosis, New Zealand, Māori, indigenous health, health equity, physical health, cardiometabolic health, premature mortality, cohort study

abstract: Background:
People experiencing psychosis are at greater risk of physical health conditions and premature mortality. It is likely that Indigenous Māori youth, who experience additional systemic inequities caused by settler-colonisation, face even greater physical health and mortality risks following a diagnosis of first-episode psychosis.
Objective:
Compare Māori and non-Māori for risk of hospitalisation and mortality for up to 15 years following first-episode psychosis diagnosis.
Methods:
A cohort (N = 14,122) of young people (16–24 years) with first-episode psychosis diagnosis between 2001 and 2019 were identified. Using crude Kaplan–Meier and adjusted Cox proportional hazards models, Māori (n = 5211) and non-Māori (n = 8911) were compared on hospitalisation and mortality outcomes for up to 15 years.
Results:
In the 15 years following first-episode psychosis diagnosis, Māori had higher adjusted risk of all-cause mortality (hazard ratio = 1.21, 95% confidence interval = [1.01, 1.45]), hospitalisation with diabetes (hazard ratio = 1.44, 95% confidence interval = [1.15, 1.79]), injury/poisoning (hazard ratio = 1.11, 95% confidence interval = [1.05, 1.16]), general physical health conditions (hazard ratio = 1.07, 95% confidence interval = [1.02, 1.13]) and also appeared to be at greater risk of cardiovascular hospitalisations (hazard ratio = 1.34, 95% confidence interval = [0.97, 1.86]). Kaplan–Meier plots show hospitalisation and mortality inequities emerging approximately 4–7 years following first-episode psychosis diagnosis.
Conclusions:
Māori are at greater risk for hospitalisation and premature mortality outcomes following first-episode psychosis. Early screening and intervention, facilitated by culturally safe health service delivery, is needed to target these inequities early.

text: The physical health and premature mortality of Indigenous Māori following first-episode psychosis diagnosis: A 15-year follow-up study Background:
People experiencing psychosis are at greater risk of physical health conditions and premature mortality. It is likely that Indigenous Māori youth, who experience additional systemic inequities caused by settler-colonisation, face even greater physical health and mortality risks following a diagnosis of first-episode psychosis.
Objective:
Compare Māori and non-Māori for risk of hospitalisation and mortality for up to 15 years following first-episode psychosis diagnosis.
Methods:
A cohort (N = 14,122) of young people (16–24 years) with first-episode psychosis diagnosis between 2001 and 2019 were identified. Using crude Kaplan–Meier and adjusted Cox proportional hazards models, Māori (n = 5211) and non-Māori (n = 8911) were compared on hospitalisation and mortality outcomes for up to 15 years.
Results:
In the 15 years following first-episode psychosis diagnosis, Māori had higher adjusted risk of all-cause mortality (hazard ratio = 1.21, 95% confidence interval = [1.01, 1.45]), hospitalisation with diabetes (hazard ratio = 1.44, 95% confidence interval = [1.15, 1.79]), injury/poisoning (hazard ratio = 1.11, 95% confidence interval = [1.05, 1.16]), general physical health conditions (hazard ratio = 1.07, 95% confidence interval = [1.02, 1.13]) and also appeared to be at greater risk of cardiovascular hospitalisations (hazard ratio = 1.34, 95% confidence interval = [0.97, 1.86]). Kaplan–Meier plots show hospitalisation and mortality inequities emerging approximately 4–7 years following first-episode psychosis diagnosis.
Conclusions:
Māori are at greater risk for hospitalisation and premature mortality outcomes following first-episode psychosis. Early screening and intervention, facilitated by culturally safe health service delivery, is needed to target these inequities early.

year: 2024