Phenology is an ecologically critical attribute that is commonly coordinated with other plant tra... more Phenology is an ecologically critical attribute that is commonly coordinated with other plant traits. Phenological shifts may be the result of evolutionary adjustments to persistently new conditions, or they may be transitory, varying with annual fluxes in abiotic conditions. In summer-dry, fire-prone Mediterranean-type climates, for example, many plant lineages have historically migrated from forests to more arid shrublands resulting in adaptive trait changes. These shifts in habitat abiotic conditions and biotic interactions influence morphology of flowers and fruits and interact with phenological timing. The Arbutoideae (Ericaceae) is one lineage that illustrates such modifications, with fruit characters evolving among genera from fleshy to dry fruit, thin to stony endocarps, and bird to rodent dispersal, among other changes. We scored herbarium collections and used ancestral trait analyses to determine phenological shifts among the five Arbutoid genera found in semi-arid climate...
The concept of the ecological community is examined from the perspective of its criteria and doma... more The concept of the ecological community is examined from the perspective of its criteria and domain. The multiple definitions and uses of this concept indicate a variety of scales and approaches. In this paper, a core definition of the minimal criteria and domain is proposed. Using those criteria, a model of the ecological community is developed based on a focal individual and its interactions with other individuals. In order to increase the scale of the domain of this approach, additional criteria are required. This model is used to explore characteristics of the minimum domain and larger scales of the community concept. The structure that emerges emphasizes context dependency and the potential for indeterminacy for most types of interactions. A prominent historical argument, the nature of boundaries between communities, has no relevance in this model.
We used molecular genetic methods to test two hypotheses, (i) that host plant specificity among e... more We used molecular genetic methods to test two hypotheses, (i) that host plant specificity among ectomycorrhizal fungi would be common in a closed-canopy, mixed Pinus contorta-Picea engelmannii forest in Yellowstone National Park and (ii) that specificity would be more common in the early successional tree species, P. contorta , than in the invader, P. engelmannii . We identified 28 ectomycorrhizal fungal species collected from 27 soil cores. The proportion of P. engelmannii to P. contorta ectomycorrhizae was nearly equal (52 and 48%, respectively). Of the 28 fungal species, 18 composed greater than 95% of the fungal community. No species was associated exclusively with P. contorta , but four species, each found in only one core, and one species found in two cores were associated exclusively with P. engelmannii . These fungi composed less than 5% of the total ectomycorrhizae. Thus, neither hypothesis was supported, and hypothesized benefits of ectomycorrhizal specificity to both tree...
There is growing concern that elite rugby participation may negatively influence brain health, bu... more There is growing concern that elite rugby participation may negatively influence brain health, but the underlying mechanisms are unclear. Cortical thickness is a widely applied biomarker of grey matter structure, but there is limited research into how it may be altered in active professional rugby players. Cross-sectional MRI data from 44 active elite rugby players, including 21 assessed within one week of head injury, and 47 healthy controls were analysed. We investigated how active elite rugby participation with and without subacute traumatic brain injury influenced grey matter structure using whole cortex and region of interest cortical thickness analyses. Relationships between cortical thickness and biomarkers of traumatic brain injury, including fractional anisotropy, plasma neurofilament light and glial fibrillary acidic protein, were also examined. In whole cortex analyses, precentral cortical thickness in the right hemisphere was lower in rugby players compared with controls...
Oxidative stress is considered one of the early underlying contributors of sepsis-induced myocard... more Oxidative stress is considered one of the early underlying contributors of sepsis-induced myocardial depression. DJ-1, also known as PARK7, has a well-established role as an antioxidant. We have previously shown, in a clinically relevant model of polymicrobial sepsis, DJ-1 deficiency improved survival and bacterial clearance by decreasing ROS production. In the present study, we investigated the role of DJ-1 in sepsis-induced myocardial depression. Here we compared wildtype (WT) with DJ-1 deficient mice at 24 and 48 h after cecal ligation and puncture (CLP). In WT mice, DJ-1 was increased in the myocardium post-CLP. DJ-1 deficient mice, despite enhanced inflammatory and oxidative responses, had an attenuated hypertrophic phenotype, less apoptosis, improved mitochondrial function, and autophagy, that was associated with preservation of myocardial function and improved survival compared to WT mice post-CLP. Collectively, these results identify DJ-1 as a regulator of myocardial functio...
Journal of Neurology, Neurosurgery & Psychiatry
BackgroundRugby is a collision sport with high rates of head injury. The effect of rugby particip... more BackgroundRugby is a collision sport with high rates of head injury. The effect of rugby participation at the elite level on cerebral grey matter structure is unclear.MethodsData from 44 active professional rugby players, including 21 acquired within one week of mild traumatic brain injury, and 47 healthy controls were analysed. Whole-cortex and region of interest analyses investigating the effects of rugby participation, sub-acute mild traumatic brain injury, and biomarkers of traumatic brain injury (fractional anisotropy, plasma neurofilament light and glial fibrillary acidic protein) on cortical thickness were performed. Plasma neurofilament light and glial fibrillary acidic protein concen- trations were measured using Single molecule array technology.ResultsWhole-cortex analysis revealed evidence of lower right hemisphere precentral cortical thickness in non-injured rugby players compared to controls. In region of interest analyses, there was evidence rugby participation predict...
AimsThe principal chaparral species in California,Adenostoma fasciculatum, an evergreen, scleroph... more AimsThe principal chaparral species in California,Adenostoma fasciculatum, an evergreen, sclerophyllous shrub, is broadly distributed and provides habitat and food resources for a large and diverse animal community. The effects of climate change, including elevated temperatures, fire frequency and severity, along with increased urban encroachment, have placed pressure on chaparral habitats in California. Our goal is to investigate aspects of reproductive ecology as a measure of the potential resiliency ofA.fasciculatum. We focus on seed rain (all seed falling into the seed traps regardless of origin) and seed banks in the context of plant-animal interactions and regeneration.MethodsStand recovery following disturbance is achieved through both resprouting and germination from established persistent soil seed banks. In this study we focus on seed ecology using a series of experiments to document the length and quantity of seed rain, seed predation, parsing the importance of the commun...
Phenology is an ecologically critical attribute that is commonly coordinated with other plant tra... more Phenology is an ecologically critical attribute that is commonly coordinated with other plant traits. Phenological shifts may be the result of evolutionary adjustments to persistently new conditions, or they may be transitory, varying with annual fluxes in abiotic conditions. In summer-dry, fire-prone Mediterranean-type climates, for example, many plant lineages have historically migrated from forests to more arid shrublands resulting in adaptive trait changes. These shifts in habitat abiotic conditions and biotic interactions influence morphology of flowers and fruits and interact with phenological timing. The Arbutoideae (Ericaceae) is one lineage that illustrates such modifications, with fruit characters evolving among genera from fleshy to dry fruit, thin to stony endocarps, and bird to rodent dispersal, among other changes. We scored herbarium collections and used ancestral trait analyses to determine phenological shifts among the five Arbutoid genera found in semi-arid climate...
The concept of the ecological community is examined from the perspective of its criteria and doma... more The concept of the ecological community is examined from the perspective of its criteria and domain. The multiple definitions and uses of this concept indicate a variety of scales and approaches. In this paper, a core definition of the minimal criteria and domain is proposed. Using those criteria, a model of the ecological community is developed based on a focal individual and its interactions with other individuals. In order to increase the scale of the domain of this approach, additional criteria are required. This model is used to explore characteristics of the minimum domain and larger scales of the community concept. The structure that emerges emphasizes context dependency and the potential for indeterminacy for most types of interactions. A prominent historical argument, the nature of boundaries between communities, has no relevance in this model.
We used molecular genetic methods to test two hypotheses, (i) that host plant specificity among e... more We used molecular genetic methods to test two hypotheses, (i) that host plant specificity among ectomycorrhizal fungi would be common in a closed-canopy, mixed Pinus contorta-Picea engelmannii forest in Yellowstone National Park and (ii) that specificity would be more common in the early successional tree species, P. contorta , than in the invader, P. engelmannii . We identified 28 ectomycorrhizal fungal species collected from 27 soil cores. The proportion of P. engelmannii to P. contorta ectomycorrhizae was nearly equal (52 and 48%, respectively). Of the 28 fungal species, 18 composed greater than 95% of the fungal community. No species was associated exclusively with P. contorta , but four species, each found in only one core, and one species found in two cores were associated exclusively with P. engelmannii . These fungi composed less than 5% of the total ectomycorrhizae. Thus, neither hypothesis was supported, and hypothesized benefits of ectomycorrhizal specificity to both tree...
There is growing concern that elite rugby participation may negatively influence brain health, bu... more There is growing concern that elite rugby participation may negatively influence brain health, but the underlying mechanisms are unclear. Cortical thickness is a widely applied biomarker of grey matter structure, but there is limited research into how it may be altered in active professional rugby players. Cross-sectional MRI data from 44 active elite rugby players, including 21 assessed within one week of head injury, and 47 healthy controls were analysed. We investigated how active elite rugby participation with and without subacute traumatic brain injury influenced grey matter structure using whole cortex and region of interest cortical thickness analyses. Relationships between cortical thickness and biomarkers of traumatic brain injury, including fractional anisotropy, plasma neurofilament light and glial fibrillary acidic protein, were also examined. In whole cortex analyses, precentral cortical thickness in the right hemisphere was lower in rugby players compared with controls...
Oxidative stress is considered one of the early underlying contributors of sepsis-induced myocard... more Oxidative stress is considered one of the early underlying contributors of sepsis-induced myocardial depression. DJ-1, also known as PARK7, has a well-established role as an antioxidant. We have previously shown, in a clinically relevant model of polymicrobial sepsis, DJ-1 deficiency improved survival and bacterial clearance by decreasing ROS production. In the present study, we investigated the role of DJ-1 in sepsis-induced myocardial depression. Here we compared wildtype (WT) with DJ-1 deficient mice at 24 and 48 h after cecal ligation and puncture (CLP). In WT mice, DJ-1 was increased in the myocardium post-CLP. DJ-1 deficient mice, despite enhanced inflammatory and oxidative responses, had an attenuated hypertrophic phenotype, less apoptosis, improved mitochondrial function, and autophagy, that was associated with preservation of myocardial function and improved survival compared to WT mice post-CLP. Collectively, these results identify DJ-1 as a regulator of myocardial functio...
Journal of Neurology, Neurosurgery & Psychiatry
BackgroundRugby is a collision sport with high rates of head injury. The effect of rugby particip... more BackgroundRugby is a collision sport with high rates of head injury. The effect of rugby participation at the elite level on cerebral grey matter structure is unclear.MethodsData from 44 active professional rugby players, including 21 acquired within one week of mild traumatic brain injury, and 47 healthy controls were analysed. Whole-cortex and region of interest analyses investigating the effects of rugby participation, sub-acute mild traumatic brain injury, and biomarkers of traumatic brain injury (fractional anisotropy, plasma neurofilament light and glial fibrillary acidic protein) on cortical thickness were performed. Plasma neurofilament light and glial fibrillary acidic protein concen- trations were measured using Single molecule array technology.ResultsWhole-cortex analysis revealed evidence of lower right hemisphere precentral cortical thickness in non-injured rugby players compared to controls. In region of interest analyses, there was evidence rugby participation predict...
AimsThe principal chaparral species in California,Adenostoma fasciculatum, an evergreen, scleroph... more AimsThe principal chaparral species in California,Adenostoma fasciculatum, an evergreen, sclerophyllous shrub, is broadly distributed and provides habitat and food resources for a large and diverse animal community. The effects of climate change, including elevated temperatures, fire frequency and severity, along with increased urban encroachment, have placed pressure on chaparral habitats in California. Our goal is to investigate aspects of reproductive ecology as a measure of the potential resiliency ofA.fasciculatum. We focus on seed rain (all seed falling into the seed traps regardless of origin) and seed banks in the context of plant-animal interactions and regeneration.MethodsStand recovery following disturbance is achieved through both resprouting and germination from established persistent soil seed banks. In this study we focus on seed ecology using a series of experiments to document the length and quantity of seed rain, seed predation, parsing the importance of the commun...
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