title: The temperature optima of enzymes: a new perspective on an old phenomenon

authors: Daniel, Roy M.

subjects: temperature optima

abstract: Careful analysis of the dependence of enzyme activity on assay temperature has revealed that some enzymes might have real temperature optima in which the decrease in catalytic rate at temperatures above the optimum is not primarily a result of irreversible thermal inactivation. The ‘equilibrium model’ has been formulated to describe genuine temperature optima, and to suggest a simple experimental method by which to distinguish these cases from those in which enzyme instability is the major determinant of temperature optima.

text: The temperature optima of enzymes: a new perspective on an old phenomenon Careful analysis of the dependence of enzyme activity on assay temperature has revealed that some enzymes might have real temperature optima in which the decrease in catalytic rate at temperatures above the optimum is not primarily a result of irreversible thermal inactivation. The ‘equilibrium model’ has been formulated to describe genuine temperature optima, and to suggest a simple experimental method by which to distinguish these cases from those in which enzyme instability is the major determinant of temperature optima.

year: 2001-04

title: Genomic signals of local adaptation across climatically heterogenous habitats in an invasive tropical fruit fly (Bactrocera tryoni)

authors: Parvizi, Elahe

abstract: Local adaptation plays a key role in the successful establishment of pest populations in new environments by enabling them to tolerate novel biotic and abiotic conditions experienced outside their native range. However, the genomic underpinnings of such adaptive responses remain unclear, especially for agriculturally important pests. We investigated population genomic signatures in the tropical/subtropical Queensland fruit fly, Bactrocera tryoni, which has an expanded range encompassing temperate and arid zones in Australia, and tropical zones in the Pacific Islands. Using reduced representation sequencing data from 28 populations, we detected allele frequency shifts associated with the native/invasive status of populations and identified environmental factors that have likely driven population differentiation. We also determined that precipitation, temperature, and geographic variables explain allelic shifts across the distribution range of B. tryoni. We found spatial heterogeneity in signatures of local adaptation across various climatic conditions in invaded areas. Specifically, disjunct invasive populations in the tropical Pacific Islands and arid zones of Australia were characterised by multiple significantly differentiated single nucleotide polymorphisms (SNPs), some of which were associated with genes with well-understood function in environmental stress (e.g., heat and desiccation) response. However, invasive populations in southeast Australian temperate zones showed higher gene flow with the native range and lacked a strong local adaptive signal. These results suggest that population connectivity with the native range has differentially affected local adaptive patterns in different invasive populations. Overall, our findings provide insights into the evolutionary underpinnings of invasion success of an important horticultural pest in climatically distinct environments.

text: Genomic signals of local adaptation across climatically heterogenous habitats in an invasive tropical fruit fly (Bactrocera tryoni) Local adaptation plays a key role in the successful establishment of pest populations in new environments by enabling them to tolerate novel biotic and abiotic conditions experienced outside their native range. However, the genomic underpinnings of such adaptive responses remain unclear, especially for agriculturally important pests. We investigated population genomic signatures in the tropical/subtropical Queensland fruit fly, Bactrocera tryoni, which has an expanded range encompassing temperate and arid zones in Australia, and tropical zones in the Pacific Islands. Using reduced representation sequencing data from 28 populations, we detected allele frequency shifts associated with the native/invasive status of populations and identified environmental factors that have likely driven population differentiation. We also determined that precipitation, temperature, and geographic variables explain allelic shifts across the distribution range of B. tryoni. We found spatial heterogeneity in signatures of local adaptation across various climatic conditions in invaded areas. Specifically, disjunct invasive populations in the tropical Pacific Islands and arid zones of Australia were characterised by multiple significantly differentiated single nucleotide polymorphisms (SNPs), some of which were associated with genes with well-understood function in environmental stress (e.g., heat and desiccation) response. However, invasive populations in southeast Australian temperate zones showed higher gene flow with the native range and lacked a strong local adaptive signal. These results suggest that population connectivity with the native range has differentially affected local adaptive patterns in different invasive populations. Overall, our findings provide insights into the evolutionary underpinnings of invasion success of an important horticultural pest in climatically distinct environments.

year: 2024

title: Dual cultural identity and tangihanga: Conflict, resolution and unexpected outcomes

authors: Edge, Kiri

subjects: bereavement

abstract: New Zealand has a significant number of dual-cultural whānau (families) which incorporate the identities of both Pākehā (New Zealander of European descent) and Māori (indigenous peoples of New Zealand). Little attention has been paid to the bereavement processes that will inevitably impact upon the lives of these whānau/families. As part of the Tangihanga Research Programme based at The University of Waikato, a directed study was conducted with a participant whose family/whānau included two life ways: Māori and Pākehā. An open-ended narrative approach was used to explore the participant’s bereavement after the death of his beloved wife. Two central themes emerged within the narrative, which related to conflict and eventual resolution. Decision-making processes and language played significant roles in the conflict experienced by the participant. Communication and compromise helped to resolve these conflicts. Unexpected outcomes included new understandings and strengthened connections between the participant and his wife’s marae.

text: Dual cultural identity and tangihanga: Conflict, resolution and unexpected outcomes New Zealand has a significant number of dual-cultural whānau (families) which incorporate the identities of both Pākehā (New Zealander of European descent) and Māori (indigenous peoples of New Zealand). Little attention has been paid to the bereavement processes that will inevitably impact upon the lives of these whānau/families. As part of the Tangihanga Research Programme based at The University of Waikato, a directed study was conducted with a participant whose family/whānau included two life ways: Māori and Pākehā. An open-ended narrative approach was used to explore the participant’s bereavement after the death of his beloved wife. Two central themes emerged within the narrative, which related to conflict and eventual resolution. Decision-making processes and language played significant roles in the conflict experienced by the participant. Communication and compromise helped to resolve these conflicts. Unexpected outcomes included new understandings and strengthened connections between the participant and his wife’s marae.

year: 2010