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• 91. [Article] Age-related loss of Nrf2, a novel mechanism for the potential attenuation of xenobiotic detoxification capacity

  Nuclear Factor, Erythroid Derived 2, Like 2 (NFE2L2 or Nrf2) is the primary transcription factor in cellular defense against oxidative and xenobiotic stresses in higher eukaryotes. This basic leucine zipper ...

  Citation × Citation Citation Abstract Copy Title: Age-related loss of Nrf2, a novel mechanism for the potential attenuation of xenobiotic detoxification capacity Author: Smith, Eric Jonathan Nuclear Factor, Erythroid Derived 2, Like 2 (NFE2L2 or Nrf2) is the primary transcription factor in cellular defense against oxidative and xenobiotic stresses in higher eukaryotes. This basic leucine zipper transcription factor regulates over 200 antioxidant, detoxification, and lipid metabolizing genes by binding to the Antioxidant Response Element (ARE; a cis-acting element) as a transcription enhancer. Our group, and others, have identified that the nuclear steady state levels of this highly inducible transcription factor declines with age which coincides with decreased expression of many ARE regulated genes. To elucidate the mechanism(s) involved in lowered Nrf2 levels we used hepatocytes isolated from young and old rats as a relevant cellular model that maintains the aging phenotype with respect to Nrf2 levels. Our results show that steady state Nrf2 levels decline by ~40% with age (N=4, p<0.05), which led us to investigate the multifaceted regulation of Nrf2 homeostasis. Specifically, analysis of Nrf2 mRNA levels, and the rate of Nrf2 protein turnover and translation were investigated. Surprisingly, Keap1-mediated degradation of Nrf2, its primary negative regulator, did not account for the age-related Nrf2 decline, nor did mRNA levels change with age. Rather, Nrf2 protein synthesis declines 5.3-fold with age (N=3, p<0.05). Furthermore, we identify that rno-miR-146a, a key inflammation regulating miRNA, both inhibits Nrf2 translation and increases significantly with age. Taken together, our data suggest that the age-related loss of Nrf2 stems from the loss of its translation and may be mediated through miR regulation. Our lab previously demonstrated in rats, that the age-related loss of Nrf2 consequentially attenuates synthesis and steady state levels of liver glutathione (GSH) synthesis and manifests as a diminished level of GSH. This antioxidant is the most abundant non-protein thiol in most cells and is pivotal for the detoxification of many xenobiotics. The rate-limiting enzyme in GSH synthesis, γ-glutamyl-cysteine ligase (Gcl), is composed of a catalytic (Gclc), and a modulatory (Gclm) subunit. In mice and humans, it is established that Nrf2, through the ARE, regulates Gclc expression. However, this had not been established in rats. From a bioinformatics analysis of the 5’ upstream sequence of the rat Gclc gene, we identified 3 putative AREs (ARE1, ARE3, and ARE4), and one cis-element containing the core but not the flanking nucleotides of the ARE (ARE2). Luciferase reporter plasmids containing each individual ARE were transfected into H4IIE rat hepatoma cells to test for ARE activity. Only one, designated “ARE4”, produced appreciable luciferase activity and was dependent on Nrf2 expression, suggesting that this ARE is a “true” enhancer element. Chromatin immunoprecipitation (ChIP) and qPCR identified that Nrf2 binds ARE4 but not ARE1-3. Further ChIP analysis identified that known partner transcription factors of Nrf2 (small maf, c-Jun and c-Fos) were also bound to ARE4. Taken together, our data demonstrates that Nrf2 regulates, in part, the expression of the rat Gclc gene through ARE4. Having identified the Gclc-AREs in the rat we sought to describe the molecular consequence of the age-related decrement of Nrf2 in hepatocytes isolated from young and old rats. ChIPs and reporter assays (ARE1-4) were used to investigate known ARE-binding transcription factors and the ARE mediated enhancement of Gclc transcription. We identified a decline in Nrf2 occupancy of ARE4 (40%) and a loss of transcriptional activity (70%; P < 0.05), consistent with the loss in Gclc levels. In addition, hepatic chromatin from old rat samples demonstrated ARE4 enrichment of the transcriptional repressor Bach1, and a loss of the histone acetyltransferase CREB-Binding Protein (CBP). These results demonstrate that the active Gclc transcriptional complex is remodeled into a repressive motif in the liver of old rats. Furthermore, ChIPs identified that Nrf2 binds ARE2 in liver lysate isolated from old rats but not young. In agreement with this finding, results from luciferase reporter assays suggest that ARE2 facilitates an Nrf2-dependent enhancement of Gclc expression in the old. Thus, a promoter switching mechanism may occur with age. In summary, we have identified key mechanisms of how the age-related decrement in Nrf2 protein levels is controlled and also gathered preliminary evidence that a pro-inflammatory state may contribute the loss of Nrf2 synthesis via increased miR levels. Finally, we have characterized the consequences of the loss of Nrf2 to GSH synthesis as an example of age-related impairment of cellular stress response. Title: Age-related loss of Nrf2, a novel mechanism for the potential attenuation of xenobiotic detoxification capacity Author: Smith, Eric Jonathan Nuclear Factor, Erythroid Derived 2, Like 2 (NFE2L2 or Nrf2) is the primary transcription factor in cellular defense against oxidative and xenobiotic stresses in higher eukaryotes. This basic leucine zipper transcription factor regulates over 200 antioxidant, detoxification, and lipid metabolizing genes by binding to the Antioxidant Response Element (ARE; a cis-acting element) as a transcription enhancer. Our group, and others, have identified that the nuclear steady state levels of this highly inducible transcription factor declines with age which coincides with decreased expression of many ARE regulated genes. To elucidate the mechanism(s) involved in lowered Nrf2 levels we used hepatocytes isolated from young and old rats as a relevant cellular model that maintains the aging phenotype with respect to Nrf2 levels. Our results show that steady state Nrf2 levels decline by ~40% with age (N=4, p<0.05), which led us to investigate the multifaceted regulation of Nrf2 homeostasis. Specifically, analysis of Nrf2 mRNA levels, and the rate of Nrf2 protein turnover and translation were investigated. Surprisingly, Keap1-mediated degradation of Nrf2, its primary negative regulator, did not account for the age-related Nrf2 decline, nor did mRNA levels change with age. Rather, Nrf2 protein synthesis declines 5.3-fold with age (N=3, p<0.05). Furthermore, we identify that rno-miR-146a, a key inflammation regulating miRNA, both inhibits Nrf2 translation and increases significantly with age. Taken together, our data suggest that the age-related loss of Nrf2 stems from the loss of its translation and may be mediated through miR regulation. Our lab previously demonstrated in rats, that the age-related loss of Nrf2 consequentially attenuates synthesis and steady state levels of liver glutathione (GSH) synthesis and manifests as a diminished level of GSH. This antioxidant is the most abundant non-protein thiol in most cells and is pivotal for the detoxification of many xenobiotics. The rate-limiting enzyme in GSH synthesis, γ-glutamyl-cysteine ligase (Gcl), is composed of a catalytic (Gclc), and a modulatory (Gclm) subunit. In mice and humans, it is established that Nrf2, through the ARE, regulates Gclc expression. However, this had not been established in rats. From a bioinformatics analysis of the 5’ upstream sequence of the rat Gclc gene, we identified 3 putative AREs (ARE1, ARE3, and ARE4), and one cis-element containing the core but not the flanking nucleotides of the ARE (ARE2). Luciferase reporter plasmids containing each individual ARE were transfected into H4IIE rat hepatoma cells to test for ARE activity. Only one, designated “ARE4”, produced appreciable luciferase activity and was dependent on Nrf2 expression, suggesting that this ARE is a “true” enhancer element. Chromatin immunoprecipitation (ChIP) and qPCR identified that Nrf2 binds ARE4 but not ARE1-3. Further ChIP analysis identified that known partner transcription factors of Nrf2 (small maf, c-Jun and c-Fos) were also bound to ARE4. Taken together, our data demonstrates that Nrf2 regulates, in part, the expression of the rat Gclc gene through ARE4. Having identified the Gclc-AREs in the rat we sought to describe the molecular consequence of the age-related decrement of Nrf2 in hepatocytes isolated from young and old rats. ChIPs and reporter assays (ARE1-4) were used to investigate known ARE-binding transcription factors and the ARE mediated enhancement of Gclc transcription. We identified a decline in Nrf2 occupancy of ARE4 (40%) and a loss of transcriptional activity (70%; P < 0.05), consistent with the loss in Gclc levels. In addition, hepatic chromatin from old rat samples demonstrated ARE4 enrichment of the transcriptional repressor Bach1, and a loss of the histone acetyltransferase CREB-Binding Protein (CBP). These results demonstrate that the active Gclc transcriptional complex is remodeled into a repressive motif in the liver of old rats. Furthermore, ChIPs identified that Nrf2 binds ARE2 in liver lysate isolated from old rats but not young. In agreement with this finding, results from luciferase reporter assays suggest that ARE2 facilitates an Nrf2-dependent enhancement of Gclc expression in the old. Thus, a promoter switching mechanism may occur with age. In summary, we have identified key mechanisms of how the age-related decrement in Nrf2 protein levels is controlled and also gathered preliminary evidence that a pro-inflammatory state may contribute the loss of Nrf2 synthesis via increased miR levels. Finally, we have characterized the consequences of the loss of Nrf2 to GSH synthesis as an example of age-related impairment of cellular stress response. Close

• 92. [Article] Families & aging : a guide to legal concerns

  Revised July 1988. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog

  Citation × Citation Citation Abstract Copy Title: Families & aging : a guide to legal concerns Author: Schmall, Vicki L., Oregon State University. Extension Service Revised July 1988. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Title: Families & aging : a guide to legal concerns Author: Schmall, Vicki L., Oregon State University. Extension Service Revised July 1988. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Close

• 93. [Article] Families & aging : a guide to legal concerns

  Published July 1985. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog

  Citation × Citation Citation Abstract Copy Title: Families & aging : a guide to legal concerns Author: Schmall, Vicki L., Oregon State University. Extension Service Published July 1985. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Title: Families & aging : a guide to legal concerns Author: Schmall, Vicki L., Oregon State University. Extension Service Published July 1985. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Close

• 94. [Article] Simulation of cattle cycle demography: cohort analysis of recruitment and culling decisions in the national beef cow herd

  This study expresses the hypothesis that historical patterns of national beef cow herd accumulation and liquidations (the cattle cycle) have been related to investment incentive differences across cow ...

  Citation × Citation Citation Abstract Copy Title: Simulation of cattle cycle demography: cohort analysis of recruitment and culling decisions in the national beef cow herd Author: Nordblom, Thomas L. This study expresses the hypothesis that historical patterns of national beef cow herd accumulation and liquidations (the cattle cycle) have been related to investment incentive differences across cow ages through time, resulting each year in changes in herd age structure, performance and potentials for adjustment in subsequent years. A review of national cattle cycle literature reveals the common assumption of variable heifer recruitment levels through time to the mature cow herd. A review of firm level cattle cycle stategy studies shows that most which considered heterogeneous herds (distinguishing performance by cow age) ironically assumed constant recruitment in proportion to cow numbers. Farmer interviews indicated that heifer recruitment may vary widely in proportion to cow numbers from year to year and that there are strong tendencies to cull non-pregnant and unsound cows from the herd at any age. The present study assumes both variable recruitment and age heterogenity. A search and synthesis of the biological literature allowed expression of economically important attributes as point estimates from continuous functions of cow age. These attributes are conception rates, health rates, cow survival rates, cull cow body weights, calf survival rates and weaning weights. Based on these biological parameters, and on the assumption that non-pregnant and unsound cows would be culled, retainment and culling rates are defined as management expectation parameters. These biological and expectation parameters are the building blocks of a simulation model designed to make value comparisons between cows of different ages and pregnancy status and to trace out changes in the national cow herd age structure through time. A budget generator produces estimates of expected net annual revenues for each of the 26 discrete age and pregnancy classes of heifers and cows, in each year from 1950 through 1978, based on exogenous price and cost series. These estimates are used to project the present values of expected future net revenues for each class of breeding animals. The ratio of future breeding value to present cull slaughter value is calculated for each of the 26 classes, each year. These V-ratios, in turn, are decision variables for determining the proportions of animals in each class to be retained in the herd, simulated by a national beef cow demography model. Annual summations from the demography model are compared with objective historical series of January 1 inventories of beef cows and replacement heifers, and annual numbers of cull cows slaughtered and beef calves born. The model's simplicity, ignoring related livestock sectors, is one of its significant features. With its few exogenous price and cost variables, simple biological relationships and management assumptions, the model is able to track the historical numbers of beef cows and calves born quite well. Mean proportional absolute deviations (MPAD) of the simulated series from the objective historical series were computed in addition to simple correlation coefficients and Theil's coefficients of inequality. In a display run, the tracking behavior of the model was best for cow inventories and calves born, and worst for heifer recruitment and cull cows, with MPAD's of .029, .036, .172, and .261, respectively. Theil's coefficients of inequality were .405, .587, .962, and .842, respectively. In an alternative run, with parameters set to reflect the assumption that all cows have the same performance characteristics across ages, the tracking behavior of the model was in several aspects about as good as the display run. Thus, the null hypothesis that performance differences across cow ages are of no importance in explaining investment behavior could not be rejected. Simulated national beef cow herd age structure changes through cattle cycles are shown from 1950 through 1978. Title: Simulation of cattle cycle demography: cohort analysis of recruitment and culling decisions in the national beef cow herd Author: Nordblom, Thomas L. This study expresses the hypothesis that historical patterns of national beef cow herd accumulation and liquidations (the cattle cycle) have been related to investment incentive differences across cow ages through time, resulting each year in changes in herd age structure, performance and potentials for adjustment in subsequent years. A review of national cattle cycle literature reveals the common assumption of variable heifer recruitment levels through time to the mature cow herd. A review of firm level cattle cycle stategy studies shows that most which considered heterogeneous herds (distinguishing performance by cow age) ironically assumed constant recruitment in proportion to cow numbers. Farmer interviews indicated that heifer recruitment may vary widely in proportion to cow numbers from year to year and that there are strong tendencies to cull non-pregnant and unsound cows from the herd at any age. The present study assumes both variable recruitment and age heterogenity. A search and synthesis of the biological literature allowed expression of economically important attributes as point estimates from continuous functions of cow age. These attributes are conception rates, health rates, cow survival rates, cull cow body weights, calf survival rates and weaning weights. Based on these biological parameters, and on the assumption that non-pregnant and unsound cows would be culled, retainment and culling rates are defined as management expectation parameters. These biological and expectation parameters are the building blocks of a simulation model designed to make value comparisons between cows of different ages and pregnancy status and to trace out changes in the national cow herd age structure through time. A budget generator produces estimates of expected net annual revenues for each of the 26 discrete age and pregnancy classes of heifers and cows, in each year from 1950 through 1978, based on exogenous price and cost series. These estimates are used to project the present values of expected future net revenues for each class of breeding animals. The ratio of future breeding value to present cull slaughter value is calculated for each of the 26 classes, each year. These V-ratios, in turn, are decision variables for determining the proportions of animals in each class to be retained in the herd, simulated by a national beef cow demography model. Annual summations from the demography model are compared with objective historical series of January 1 inventories of beef cows and replacement heifers, and annual numbers of cull cows slaughtered and beef calves born. The model's simplicity, ignoring related livestock sectors, is one of its significant features. With its few exogenous price and cost variables, simple biological relationships and management assumptions, the model is able to track the historical numbers of beef cows and calves born quite well. Mean proportional absolute deviations (MPAD) of the simulated series from the objective historical series were computed in addition to simple correlation coefficients and Theil's coefficients of inequality. In a display run, the tracking behavior of the model was best for cow inventories and calves born, and worst for heifer recruitment and cull cows, with MPAD's of .029, .036, .172, and .261, respectively. Theil's coefficients of inequality were .405, .587, .962, and .842, respectively. In an alternative run, with parameters set to reflect the assumption that all cows have the same performance characteristics across ages, the tracking behavior of the model was in several aspects about as good as the display run. Thus, the null hypothesis that performance differences across cow ages are of no importance in explaining investment behavior could not be rejected. Simulated national beef cow herd age structure changes through cattle cycles are shown from 1950 through 1978. Close

• 95. [Article] Changes in gene expression related to the decline of the aging immune system

  In this study, the gene expression levels between 6 month old mice and 26 month old mice were compared. The purpose of this research was to identify genes that are differentially regulated due to aging. ...

  Citation × Citation Citation Abstract Copy Title: Changes in gene expression related to the decline of the aging immune system Author: Gombart, Adrian F., Tran, Jenny K. In this study, the gene expression levels between 6 month old mice and 26 month old mice were compared. The purpose of this research was to identify genes that are differentially regulated due to aging. The results showed 148 significantly differentiated genes in the analysis of a total of 44,170 genes with 16 genes found to be related to immunity and inflammation. Title: Changes in gene expression related to the decline of the aging immune system Author: Gombart, Adrian F., Tran, Jenny K. In this study, the gene expression levels between 6 month old mice and 26 month old mice were compared. The purpose of this research was to identify genes that are differentially regulated due to aging. The results showed 148 significantly differentiated genes in the analysis of a total of 44,170 genes with 16 genes found to be related to immunity and inflammation. Close

• 96. [Article] Influence of marine environment on age and size at maturity, growth, and abundance of chum salmon, Ohcorhynchus keta (Walbaum), from Olsen Creek, Prince William Sound, Alaska

  Effects of the marine environment on age and size at maturity, early marine growth, and abundance of chum salmon, Oncorhynchus keta, were studied at Olsen Creek during 1959-77. Chum salmon returned to ...

  Citation × Citation Citation Abstract Copy Title: Influence of marine environment on age and size at maturity, growth, and abundance of chum salmon, Ohcorhynchus keta (Walbaum), from Olsen Creek, Prince William Sound, Alaska Author: Helle, John H. Effects of the marine environment on age and size at maturity, early marine growth, and abundance of chum salmon, Oncorhynchus keta, were studied at Olsen Creek during 1959-77. Chum salmon returned to Olsen Creek as predominately 3-, 4-, and 5-year fish; however, age composition varied from year to year. The mean age composition for the brood years 1956-72 for males was 15%, 66%, and 19% for 3-, 4-, and 5-year fish, respectively. Mean age composition for females of the same broods showed slightly higher percentages of older fish: 9%, 67%, and 23% for 3-, 4-, and 5-year fish, respectively. Some 6-year chum salmon returned to Olsen Creek between 1968 and 1975; but, only in 1973 did the number of 6-year fish (3%) represent more than 1% of the returns. Population sizes tended to be larger during these years, and mean age increased as the number of fish in a brood increased. Intraseasonally, age of new chum salmon spawners at Olsen Creek decreased as the season progressed. Mean size of older spawners was greater than the mean size of younger spawners; but, the ranges in size of the three age groups overlap each other so size is not a good criterion for estimating age of chum salmon. Measurement of circuli and distances on adult scales were used to estimate growth of chum salmon during their first two years of marine life. Both number of circuli and distances on scales of juvenile chum salmon after their first summer in Prince William Sound were shown to be related to length of the fish. Growth during the first season at sea was not related to age at maturity; however, amount of growth acquired during the second marine season was negatively related to age at maturity. Growth during the first summer at sea was related to sea surface temperatures and marine weather parameters in Prince William Sound and in the northern Gulf of Alaska. Location of chum salmon from Olsen Creek during their second year at sea is unknown. Fluctuations in size (length) at maturity were more similar between fish from different broods returning during the same year than they were for fish that matured at different ages from the same broods. Length at maturity was related to marine weather factors during their last summer at sea in the northern Gulf of Alaska and Prince William Sound. Length at maturity was also related to mean summer sea surface temperature in Prince William Sound during the year of return. Total survival of each brood was estimated from the ratio of number of progeny (returns) to number of parents (spawners). No direct relationships were found between survival and growth during the first or second season in the sea, sea surface temperatures, or upwelling indices along the coast. However, a highly significant relationship was found between the survival of progeny and mean length of the parents. Title: Influence of marine environment on age and size at maturity, growth, and abundance of chum salmon, Ohcorhynchus keta (Walbaum), from Olsen Creek, Prince William Sound, Alaska Author: Helle, John H. Effects of the marine environment on age and size at maturity, early marine growth, and abundance of chum salmon, Oncorhynchus keta, were studied at Olsen Creek during 1959-77. Chum salmon returned to Olsen Creek as predominately 3-, 4-, and 5-year fish; however, age composition varied from year to year. The mean age composition for the brood years 1956-72 for males was 15%, 66%, and 19% for 3-, 4-, and 5-year fish, respectively. Mean age composition for females of the same broods showed slightly higher percentages of older fish: 9%, 67%, and 23% for 3-, 4-, and 5-year fish, respectively. Some 6-year chum salmon returned to Olsen Creek between 1968 and 1975; but, only in 1973 did the number of 6-year fish (3%) represent more than 1% of the returns. Population sizes tended to be larger during these years, and mean age increased as the number of fish in a brood increased. Intraseasonally, age of new chum salmon spawners at Olsen Creek decreased as the season progressed. Mean size of older spawners was greater than the mean size of younger spawners; but, the ranges in size of the three age groups overlap each other so size is not a good criterion for estimating age of chum salmon. Measurement of circuli and distances on adult scales were used to estimate growth of chum salmon during their first two years of marine life. Both number of circuli and distances on scales of juvenile chum salmon after their first summer in Prince William Sound were shown to be related to length of the fish. Growth during the first season at sea was not related to age at maturity; however, amount of growth acquired during the second marine season was negatively related to age at maturity. Growth during the first summer at sea was related to sea surface temperatures and marine weather parameters in Prince William Sound and in the northern Gulf of Alaska. Location of chum salmon from Olsen Creek during their second year at sea is unknown. Fluctuations in size (length) at maturity were more similar between fish from different broods returning during the same year than they were for fish that matured at different ages from the same broods. Length at maturity was related to marine weather factors during their last summer at sea in the northern Gulf of Alaska and Prince William Sound. Length at maturity was also related to mean summer sea surface temperature in Prince William Sound during the year of return. Total survival of each brood was estimated from the ratio of number of progeny (returns) to number of parents (spawners). No direct relationships were found between survival and growth during the first or second season in the sea, sea surface temperatures, or upwelling indices along the coast. However, a highly significant relationship was found between the survival of progeny and mean length of the parents. Close

• 97. [Article] Estimation of Population Age Structure, Detection Probability, and Density of Red Tree Voles in Oregon

  Red tree voles (Arborimus longicaudus) are a unique species of Arvicoline rodent found in western Oregon and northwest California. Their preferred habitat is mature and old-growth coniferous forest dominated ...

  Citation × Citation Citation Abstract Copy Title: Estimation of Population Age Structure, Detection Probability, and Density of Red Tree Voles in Oregon Author: Marks-Fife, Chad A. Red tree voles (Arborimus longicaudus) are a unique species of Arvicoline rodent found in western Oregon and northwest California. Their preferred habitat is mature and old-growth coniferous forest dominated by Douglas-fir (Pseudotsuga menziesii). Tree voles are an important prey item for northern spotted owls and many other predators, but are extremely difficult to sample. As a result, little is known about their abundance or population dynamics. We used several methods to describe tree vole detectability, density, and population age structure. We verified a relationship between molar tooth development and age in red tree voles, allowing us to estimate the age of voles recovered in pellets regurgitated by spotted owls in Oregon. We found that the age distribution of tree voles in spotted owl pellets varied from year to year but not from region to region within the species range. We found evidence for a positive relationship between annual precipitation and the proportion of juvenile tree voles in owl pellets on one of two study areas. We conducted modified line-transect surveys at 31 locations representing three forest stand age classes (young, mature, old) in the Oregon Coast Range to visually detect potential red tree vole nests. We climbed trees where potential nests were detected from the ground in order to determine the species and the occupancy status of nests. We used the transect and climbing data and distance sampling techniques to estimate detection probabilities and density of active tree vole nest trees in relation to forest age class. Our surveys suggested that density of tree vole nest trees increased with forest age, whereas detection probability of nest trees decreased with forest age. Regardless of forest age, mean detection probability of nest trees was low (< 30%). We used estimates of nest tree density on our study area to estimate the minimum density of adult tree voles (~1.91/ha) and the density of individual tree vole home ranges (~4.2/ha). These estimates of detection probability and density suggest that only a small proportion of nest trees are detected and buffered against disturbance using methods described in the survey protocol used by federal agencies in Oregon and California. We recommend methods to improve detection rates of nest trees, including application of our density estimates to occupied stands, modification of stand-specific data using our estimates of detection probability, performing full-tree nest searches in every tree climbed, performing a 100 m search radius around confirmed nest trees, and targeting larger-than-average trees (with respect to stand-specific data) for spot searches. Title: Estimation of Population Age Structure, Detection Probability, and Density of Red Tree Voles in Oregon Author: Marks-Fife, Chad A. Red tree voles (Arborimus longicaudus) are a unique species of Arvicoline rodent found in western Oregon and northwest California. Their preferred habitat is mature and old-growth coniferous forest dominated by Douglas-fir (Pseudotsuga menziesii). Tree voles are an important prey item for northern spotted owls and many other predators, but are extremely difficult to sample. As a result, little is known about their abundance or population dynamics. We used several methods to describe tree vole detectability, density, and population age structure. We verified a relationship between molar tooth development and age in red tree voles, allowing us to estimate the age of voles recovered in pellets regurgitated by spotted owls in Oregon. We found that the age distribution of tree voles in spotted owl pellets varied from year to year but not from region to region within the species range. We found evidence for a positive relationship between annual precipitation and the proportion of juvenile tree voles in owl pellets on one of two study areas. We conducted modified line-transect surveys at 31 locations representing three forest stand age classes (young, mature, old) in the Oregon Coast Range to visually detect potential red tree vole nests. We climbed trees where potential nests were detected from the ground in order to determine the species and the occupancy status of nests. We used the transect and climbing data and distance sampling techniques to estimate detection probabilities and density of active tree vole nest trees in relation to forest age class. Our surveys suggested that density of tree vole nest trees increased with forest age, whereas detection probability of nest trees decreased with forest age. Regardless of forest age, mean detection probability of nest trees was low (< 30%). We used estimates of nest tree density on our study area to estimate the minimum density of adult tree voles (~1.91/ha) and the density of individual tree vole home ranges (~4.2/ha). These estimates of detection probability and density suggest that only a small proportion of nest trees are detected and buffered against disturbance using methods described in the survey protocol used by federal agencies in Oregon and California. We recommend methods to improve detection rates of nest trees, including application of our density estimates to occupied stands, modification of stand-specific data using our estimates of detection probability, performing full-tree nest searches in every tree climbed, performing a 100 m search radius around confirmed nest trees, and targeting larger-than-average trees (with respect to stand-specific data) for spot searches. Close

• 98. [Article] Timescales of large silicic magma systems : implications from accessory minerals in Pleistocene lavas of the Altiplano-Puna Volcanic Complex, central Andes

  Constraining the development, evolution, and timescales of large silicic magma systems is important to understanding the development of granite batholiths, the relationships between volcanoes and their ...

  Citation × Citation Citation Abstract Copy Title: Timescales of large silicic magma systems : implications from accessory minerals in Pleistocene lavas of the Altiplano-Puna Volcanic Complex, central Andes Author: Tierney, Casey R. Constraining the development, evolution, and timescales of large silicic magma systems is important to understanding the development of granite batholiths, the relationships between volcanoes and their plutonic underpinnings, and the development of the continental crust. The ignimbrite flare up that produced the Altiplano-Puna Volcanic Complex of the Central Andes is characterized by episodic volcanism over a ~11 Ma time-span that climaxed about 4 Ma. Since peak activity, the temporal and spatial record of volcanism suggests a waning of the system with only one other supervolcanic eruption at 2.6 Ma. The most recent phase of volcanism from the APVC comprises a series of late Pleistocene domes that share a general petrochemical resemblance to the ignimbrites. New U-Th/U-Pb data on zircons and high precision 40Ar/39Ar age determinations reveal that these effusive eruptions represent a temporally coherent magmatic episode. The five largest domes (Chao, Chillahuita, Chanka, Chascon-Runtu Jarita, and Tocopuri) have a combined volume >40 km³, and are distributed over a roughly elliptical area of almost 2000km² centered at 22°S 68°W. They are crystal rich (>50%) dacites to rhyolites. ⁴⁰Ar/³⁹Ar ages from biotite reveals eruption ages from 108±6 to 120±5 ka while more accurate sanidine for some of the domes reveal eruption ages from 87±4 to 97±2 ka. SIMS U-series crystallization ages from the rims of 215 zircon crystals from the domes show a similar age spectra from dome to dome, with common peaks in zircon ages at ~100ka and ~220ka. Furthermore, the ages reveal a fairly continuous spread of ages from near eruption to >300ka indicating that the residence time of this magma body was likely over a similar time interval. Ubiquitous andesitic inclusions evidence a vital role for recharge in sustaining and maybe eventual eruption of these magmas. Lastly, the interiors of crystals with rim U-Th secular equilibrium ages were re-analyzed and have yielded U-Pb ages of up to 3.5 Ma. The presence of these older interiors suggests that the source region of these magmas retained a record of an earlier history dating back to the last supervolcanic eruption in the region from the nearby Pastos Grandes caldera. This suggests that the thermal history of the system precluded complete resorption of antecrysts. The volcanological, petrological, temporal and spatial coherence of this series of eruptions combined with the similar ⁴⁰Ar/³⁹Ar and zircon age spectra argue for a long-lived and unitary magma chamber revealing perhaps the waning of this major continental magma system. Title: Timescales of large silicic magma systems : implications from accessory minerals in Pleistocene lavas of the Altiplano-Puna Volcanic Complex, central Andes Author: Tierney, Casey R. Constraining the development, evolution, and timescales of large silicic magma systems is important to understanding the development of granite batholiths, the relationships between volcanoes and their plutonic underpinnings, and the development of the continental crust. The ignimbrite flare up that produced the Altiplano-Puna Volcanic Complex of the Central Andes is characterized by episodic volcanism over a ~11 Ma time-span that climaxed about 4 Ma. Since peak activity, the temporal and spatial record of volcanism suggests a waning of the system with only one other supervolcanic eruption at 2.6 Ma. The most recent phase of volcanism from the APVC comprises a series of late Pleistocene domes that share a general petrochemical resemblance to the ignimbrites. New U-Th/U-Pb data on zircons and high precision 40Ar/39Ar age determinations reveal that these effusive eruptions represent a temporally coherent magmatic episode. The five largest domes (Chao, Chillahuita, Chanka, Chascon-Runtu Jarita, and Tocopuri) have a combined volume >40 km³, and are distributed over a roughly elliptical area of almost 2000km² centered at 22°S 68°W. They are crystal rich (>50%) dacites to rhyolites. ⁴⁰Ar/³⁹Ar ages from biotite reveals eruption ages from 108±6 to 120±5 ka while more accurate sanidine for some of the domes reveal eruption ages from 87±4 to 97±2 ka. SIMS U-series crystallization ages from the rims of 215 zircon crystals from the domes show a similar age spectra from dome to dome, with common peaks in zircon ages at ~100ka and ~220ka. Furthermore, the ages reveal a fairly continuous spread of ages from near eruption to >300ka indicating that the residence time of this magma body was likely over a similar time interval. Ubiquitous andesitic inclusions evidence a vital role for recharge in sustaining and maybe eventual eruption of these magmas. Lastly, the interiors of crystals with rim U-Th secular equilibrium ages were re-analyzed and have yielded U-Pb ages of up to 3.5 Ma. The presence of these older interiors suggests that the source region of these magmas retained a record of an earlier history dating back to the last supervolcanic eruption in the region from the nearby Pastos Grandes caldera. This suggests that the thermal history of the system precluded complete resorption of antecrysts. The volcanological, petrological, temporal and spatial coherence of this series of eruptions combined with the similar ⁴⁰Ar/³⁹Ar and zircon age spectra argue for a long-lived and unitary magma chamber revealing perhaps the waning of this major continental magma system. Close

• 99. [Article] An assessment of the reproductive cycle in black rockfish, Sebastes melanops (Girard, 1856) on the central Oregon Coast : a blood plasma protein and sex steroid used as potential indicators of sex and stage of gonadal maturity

  Because of large declines in abundance of many Eastern Pacific rockfish populations (Genus Sebastes), there has been an increasing effort to improve our understanding of the role of spawning population ...

  Citation × Citation Citation Abstract Copy Title: An assessment of the reproductive cycle in black rockfish, Sebastes melanops (Girard, 1856) on the central Oregon Coast : a blood plasma protein and sex steroid used as potential indicators of sex and stage of gonadal maturity Author: Martin-Mills, Brooke E. Because of large declines in abundance of many Eastern Pacific rockfish populations (Genus Sebastes), there has been an increasing effort to improve our understanding of the role of spawning population characteristics and individual reproductive success in recruitment variability and population dynamics. Current methods for assessing sex and maturational status in rockfishes are lethal, so fishery managers would benefit from a non-lethal method to assess the reproductive potential of rockfish populations. I developed a biochemical assay to determine sex and stage of female maturity in black rockfish (Sebastes melanops) using a blood plasma indicator vitellogenin (VTG). The specific objectives of this research were to: 1) describe the annual hormonal and gonadal changes associated with reproduction and 2) describe the timing of reproduction in female black rockfish of different age classes. Estradiol-17β (E2) and VTG concentrations were compared with histologically determined ovarian stages of female maturity (i.e. pre-vitellogenic, early vitellogenic, mid-vitellogenic, post-vitellogenic, oocyte maturation, and post-spawned) from 325 female black rockfish sampled by hook-and-line from the central Oregon coast from September 2003 to January 2005. I also measured E2 and VTG in male fish from the same time period. VTG concentrations detected in field-collected blood samples reflected the seasonal cycle reported in previous studies. Mean concentrations of VTG in mid-vitellogenic, post-vitellogenic, and females undergoing oocyte maturation can be used to distinguish between pre-vitellogenic females and early vitellogenic females during the spawning season (P<0.05). Females can be distinguished from males based on VTG concentrations (P<0.0001), with the exception of pre-vitellogenic and post-spawned females (immature fish and mature female fish in non-reproductive summer months). Mean E2 concentrations were not as accurate for identification of sex and each individual stage of female maturity, although mid-vitellogenic and post-vitellogenic females had significantly higher concentrations of E2 than pre-vitellogenic females (P<0.05). Mean concentrations of E2 in mid-vitellogenic females, post-vitellogenic females, and females undergoing oocyte maturation were higher than in males (P<0.0001). A Discriminant Function Analysis (DFA) identified VTG as the best predictor for predicting sex from plasma samples, with, 82% of fish correctly classified by sex. Of the 100 females and 30 males examined, 68% of females and 97% of males were correctly classified. The DFA choose plasma VTG, total length, and weight as the best predictors of stage of maturity in females and some stages could be distinguished from each other with ≈65% accuracy. The second goal of this research was to use the biochemical assay to investigate the differences in timing of reproduction in young and older females in this species. In the fall (September-November) females age 5-8 made up 43 % of early and mid-vitellogenic (stage 3 and 4) females, where as, age 9+ females made up 100% of the females that were post-vitellogenic (stage 5) and undergoing oocyte maturation (stage 6). Females’ ages 6-8 captured in the winter months (December-February) made up 90% of the mid- and late vitellogenic (stage 4 and 5) and 100% of post-spawned (stages 7 and 8) fish. In the spring (March-May) 40% of post-spawned females were age 8 and 60% were age 9+. These results suggest that older females have more of a protracted spawning period than younger fish. Females from all age categories showed a similar trend of hormone and protein cycling. Concentrations of E2 and VTG increased throughout September-December, peaked in February, decreased and remained low until the end of August. Concentrations of E2 for early vitellogenic (stage 3) fish of the age 9+ were significantly higher than in females ages 3-5. Females’ age 9+ undergoing oocyte maturation (stage 6) had higher concentrations of E2 than females ages 6-8. Early vitellogenic (stage 3) and mid-vitellogenic (stage 4) females ages 6-8 and 9+ had higher concentrations of VTG than in females ages 3-5. Small samples sizes were prohibitive in comparing VTG and E2 concentrations between all age groups and stages of maturity, and I did not find conclusive evidence of differences in seasonal VTG or E2 levels among age groups. Potentially, this newly developed vitellogenin assay may be used for other rockfish species, providing a non-lethal assessment tool to differentiate between sex and stage of maturity in females. Title: An assessment of the reproductive cycle in black rockfish, Sebastes melanops (Girard, 1856) on the central Oregon Coast : a blood plasma protein and sex steroid used as potential indicators of sex and stage of gonadal maturity Author: Martin-Mills, Brooke E. Because of large declines in abundance of many Eastern Pacific rockfish populations (Genus Sebastes), there has been an increasing effort to improve our understanding of the role of spawning population characteristics and individual reproductive success in recruitment variability and population dynamics. Current methods for assessing sex and maturational status in rockfishes are lethal, so fishery managers would benefit from a non-lethal method to assess the reproductive potential of rockfish populations. I developed a biochemical assay to determine sex and stage of female maturity in black rockfish (Sebastes melanops) using a blood plasma indicator vitellogenin (VTG). The specific objectives of this research were to: 1) describe the annual hormonal and gonadal changes associated with reproduction and 2) describe the timing of reproduction in female black rockfish of different age classes. Estradiol-17β (E2) and VTG concentrations were compared with histologically determined ovarian stages of female maturity (i.e. pre-vitellogenic, early vitellogenic, mid-vitellogenic, post-vitellogenic, oocyte maturation, and post-spawned) from 325 female black rockfish sampled by hook-and-line from the central Oregon coast from September 2003 to January 2005. I also measured E2 and VTG in male fish from the same time period. VTG concentrations detected in field-collected blood samples reflected the seasonal cycle reported in previous studies. Mean concentrations of VTG in mid-vitellogenic, post-vitellogenic, and females undergoing oocyte maturation can be used to distinguish between pre-vitellogenic females and early vitellogenic females during the spawning season (P<0.05). Females can be distinguished from males based on VTG concentrations (P<0.0001), with the exception of pre-vitellogenic and post-spawned females (immature fish and mature female fish in non-reproductive summer months). Mean E2 concentrations were not as accurate for identification of sex and each individual stage of female maturity, although mid-vitellogenic and post-vitellogenic females had significantly higher concentrations of E2 than pre-vitellogenic females (P<0.05). Mean concentrations of E2 in mid-vitellogenic females, post-vitellogenic females, and females undergoing oocyte maturation were higher than in males (P<0.0001). A Discriminant Function Analysis (DFA) identified VTG as the best predictor for predicting sex from plasma samples, with, 82% of fish correctly classified by sex. Of the 100 females and 30 males examined, 68% of females and 97% of males were correctly classified. The DFA choose plasma VTG, total length, and weight as the best predictors of stage of maturity in females and some stages could be distinguished from each other with ≈65% accuracy. The second goal of this research was to use the biochemical assay to investigate the differences in timing of reproduction in young and older females in this species. In the fall (September-November) females age 5-8 made up 43 % of early and mid-vitellogenic (stage 3 and 4) females, where as, age 9+ females made up 100% of the females that were post-vitellogenic (stage 5) and undergoing oocyte maturation (stage 6). Females’ ages 6-8 captured in the winter months (December-February) made up 90% of the mid- and late vitellogenic (stage 4 and 5) and 100% of post-spawned (stages 7 and 8) fish. In the spring (March-May) 40% of post-spawned females were age 8 and 60% were age 9+. These results suggest that older females have more of a protracted spawning period than younger fish. Females from all age categories showed a similar trend of hormone and protein cycling. Concentrations of E2 and VTG increased throughout September-December, peaked in February, decreased and remained low until the end of August. Concentrations of E2 for early vitellogenic (stage 3) fish of the age 9+ were significantly higher than in females ages 3-5. Females’ age 9+ undergoing oocyte maturation (stage 6) had higher concentrations of E2 than females ages 6-8. Early vitellogenic (stage 3) and mid-vitellogenic (stage 4) females ages 6-8 and 9+ had higher concentrations of VTG than in females ages 3-5. Small samples sizes were prohibitive in comparing VTG and E2 concentrations between all age groups and stages of maturity, and I did not find conclusive evidence of differences in seasonal VTG or E2 levels among age groups. Potentially, this newly developed vitellogenin assay may be used for other rockfish species, providing a non-lethal assessment tool to differentiate between sex and stage of maturity in females. Close

• 100. [Article] Retirement-age migration to and from Oregon : who is still on the Oregon Trail?

  Oregon, much like the nation, has historically had a paradoxical relationship to migration. Oregon is famous for the Lewis and Clark expedition and the Oregon Trail. It is, and always has been, greatly ...

  Citation × Citation Citation Abstract Copy Title: Retirement-age migration to and from Oregon : who is still on the Oregon Trail? Author: Gagnier, Cliff R. Oregon, much like the nation, has historically had a paradoxical relationship to migration. Oregon is famous for the Lewis and Clark expedition and the Oregon Trail. It is, and always has been, greatly affected and inspired by interstate migration yet each successive generation has been less than welcoming to further migration. Today, Oregon is a desirable destination for retirement-aged migrants for its scenic beauty and mild seasons. This essay will use census data from 2000 to describe the characteristics associated with retirement-age migrants to Oregon. Multinomial logistic regression analysis is used to compare retirement-aged Oregon in-migrants with Oregon non-movers, Oregon out-migrants and non-movers and out-migrants of the states from which in-migrants to Oregon originated. In three cases, the characteristics effecting the decision to migrate are determined by comparing a migrant group population with its respective non-mover population. This essay is a useful tool for those seeking to understand the characteristics important to retirement-age migration to Oregon as well as the factors influencing the migration decision. Title: Retirement-age migration to and from Oregon : who is still on the Oregon Trail? Author: Gagnier, Cliff R. Oregon, much like the nation, has historically had a paradoxical relationship to migration. Oregon is famous for the Lewis and Clark expedition and the Oregon Trail. It is, and always has been, greatly affected and inspired by interstate migration yet each successive generation has been less than welcoming to further migration. Today, Oregon is a desirable destination for retirement-aged migrants for its scenic beauty and mild seasons. This essay will use census data from 2000 to describe the characteristics associated with retirement-age migrants to Oregon. Multinomial logistic regression analysis is used to compare retirement-aged Oregon in-migrants with Oregon non-movers, Oregon out-migrants and non-movers and out-migrants of the states from which in-migrants to Oregon originated. In three cases, the characteristics effecting the decision to migrate are determined by comparing a migrant group population with its respective non-mover population. This essay is a useful tool for those seeking to understand the characteristics important to retirement-age migration to Oregon as well as the factors influencing the migration decision. Close