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001-es BibID:BIBFORM107665
035-os BibID:(WoS)000417239200011 (Scopus)85021384601
Első szerző:Fanson, Kerry V.
Cím:Inter-laboratory variation in corticosterone measurement: Implications for comparative ecological and evolutionary studies / Kerry V. Fanson, Zoltán Németh, Marilyn Ramenofsky, John C. Wingfield, Katherine L. Buchanan
Dátum:2017
ISSN:2041-210X
Megjegyzések:Interspecific comparisons of endocrine data are useful for drawing broad conclusions concerning the role of ecological variables in the evolution of physiological pathways. However, comparisons of endocrine data generated by different research groups are problematic, due to inter-laboratory variation in measured hormone values. To date, we know of no study which has quantified the extent of inter-laboratory variation in the measurement of hormone levels, outside of biomedical studies. To evaluate the extent to which laboratories differ in their measurement of hormones, we prepared seven samples of avian plasma with known concentrations of corticosterone and sent them for blind analyses to 19 laboratories and asked them to report the methods used and the values obtained. Both absolute hormone concentrations and the ratios between samples were equally variable, up to an order of magnitude different for some concentrations. Laboratory identity accounted for more than 80% of the variation in reported corticosterone, but we could not identify any methodological factors that consistently contributed to this inter-laboratory variation. In addition, laboratory measurement error was significantly correlated with the latitude of the primary study species for each laboratory, suggesting that inter-laboratory variation has the potential to drive trends in corticosterone datasets. Inter-laboratory variation in corticosterone measurement may have serious implications for quantitative comparisons of endocrine values across laboratories, although comparisons of qualitative patterns may be more robust because rank order of the samples was relatively consistent across laboratories. Ignoring laboratory effect and the non-independence of data may lead to an inflated rate of Type I error and spurious correlations.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
comparative endocrinology
corticosterone
enzyme immunoassay
measurement error
meta-analysis
radioimmunoassay
stress
Megjelenés:Methods in Ecology and Evolution. - 8 : 12 (2017), p. 1745-1754. -
További szerzők:Németh Zoltán (1976-) (biológus) Ramenofsky, Marilyn Wingfield, John C. Buchanan, Katherine L.
Pályázati támogatás:NPD 121013
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2.

001-es BibID:BIBFORM107672
035-os BibID:(WoS)000368560000005 (Scopus)84957921974
Első szerző:Krause, Jesse S.
Cím:Annual Hematocrit Profiles in Two Subspecies of White-Crowned Sparrow : A Migrant and a Resident Comparison / Jesse S. Krause, Zoltán Németh, Jonathan H. Pérez, Helen E. Chmura, Marilyn Ramenofsky, John C. Wingfield
Dátum:2016
ISSN:1522-2152
Megjegyzések:Hematocrit is an easily measured parameter that can be used to assess changes in oxygen carrying capacity necessitated by fluctuations in metabolic demands. Most hematocrit studies draw conclusions from changes in hematocrit that occur over a small sampling interval without an understanding of the variation that exists across the annual cycle. White-crowned sparrows provide an excellent model system due to the existence of a resident subspecies (Zonotrichia leucophrys nuttalli) that serves as a natural control for a migrant subspecies (Zonotrichia leucophrys gambelii). Comparing these two subspecies allows for the investigation of adaptive physiological changes at each life-history stage (i.e., migration, breeding, molt, etc.) in response to changing metabolic demands. Of particular interest, this subspecies comparison, by both calendar month and lifehistory stage, allows for the separation of adaptive increases in hematocrit due to migration fromthe natural seasonal variation in hematocrit. Hematocrit levels for males and females ranged throughout the year between 42%?47% and 40%?47% in the resident and between 45%?58% and 45%?56% in the migrant. In both subspecies, hematocrit levels were elevated during the breeding season compared to the nonbreeding season, and levels were reduced in females during egg laying. When grouped by life-history stage, hematocrit levels were always higher in the migrant compared to the resident. During the months in which migration occurred, hematocrit levels were 10%?12% higher in the migrant compared to the resident subspecies. These data suggest differential regulation of hematocrit between the two subspecies that may be attributed to phenotypic plasticity or genetic differences.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
life-history stage
migration, molt
breeding biology
red blood cells
annual cycle
Megjelenés:Physiological And Biochemical Zoology. - 89 : 1 (2016), p. 51-60. -
További szerzők:Németh Zoltán (1976-) (biológus) Pérez, Jonathan H. Chmura, Helen E. Ramenofsky, Marilyn Wingfield, John C.
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3.

001-es BibID:BIBFORM107062
035-os BibID:(WoS)000612128700018 (Scopus)85096396692
Első szerző:Krause, Jesse S.
Cím:Annual regulation of adrenocortical function in migrant and resident subspecies of white-crowned sparrow / Jesse S. Krause, Zoltán Németh, Jonathan H. Pérez, Helen E. Chmura, Karen R. Word, Hannah J. Lau, Ryan E. Swanson, Jeffrey C. Cheah, Lisa N. Quach, Simone L. Meddle, John C. Wingfield, Marilyn Ramenofsky
Dátum:2021
ISSN:0018-506X
Megjegyzések:Corticosterone affects physiology and behavior both during normal daily processes but also in response to environmental challenges and is known to mediate life history trade-offs. Many studies have investigated patterns of corticosterone production at targeted times of year, while ignoring underlying annual profiles. We aimed to understand the annual regulation of hypothalamic-pituitary-adrenal (HPA) axis function of both migrant (Zonotrichia leucophrys gambelii; n = 926) and resident (Z. l. nutalli; n = 688) subspecies of white-crowned sparrow and how it is influenced by environmental conditions wind, precipitation, and temperature. We predicted that more dramatic seasonal changes in baseline and stress-induced corticosterone would occur in migrants to precisely time the onset of breeding and cope with environmental extremes on their arctic breeding grounds, while changes in residents would be muted as they experience a more forgiving breeding schedule and comparatively benign environmental conditions in coastal California. During the course of a year, the harshest conditions were experienced the summer breeding grounds for migrants, at which point they had higher corticosterone levels compared to residents. For residents, the winter months coincided with harshest conditions at which point they had higher corticosterone levels than migrants. For both subspecies, corticosterone tended to rise as environmental conditions became colder and windier. We found that the annual maxima in stress-induced corticosterone occurred prior to egg lay for all birds except resident females. Migrants had much higher baseline and acute stress-induced corticosterone during breeding compared to residents; where in a harsher environment the timing of the onset of reproduction is more critical because the breeding season is shorter. Interestingly, molt was the only stage within the annual cycle in which subspecies differences were absent suggesting that a requisite reduction in corticosterone may have to be met for feather growth. These data suggest that modulation of the HPA axis is largely driven by environmental factors, social cues, and their potential interactions with a genetic program.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Stress
Hypothalamic pituitary adrenal (HPA) axis
Life history stage
Subspecies
Corticosterone
Restrain
Latitude
Breeding season
Megjelenés:Hormones And Behavior. - 127 : 104884 (2021), p. 1-9. -
További szerzők:Németh Zoltán (1976-) (biológus) Pérez, Jonathan H. Chmura, Helen E. Word, Karen R. Lau, Hannah J. Swanson, Ryan E. Cheah, Jeffrey C. Quach, Lisa N. Meddle, Simone L. Wingfield, John C. Ramenofsky, Marilyn
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4.

001-es BibID:BIBFORM103437
035-os BibID:(Wos)000511336100016 (Scopus)85069708060
Első szerző:Lisovski, Simeon
Cím:Migration pattern of Gambel's White-crowned Sparrow along the Pacific Flyway / Simeon Lisovski, Zoltán Németh, John C. Wingfield, Jesse S. Krause, Keith A. Hobson, Nathaniel E. Seavy, Jennifer Gee, Marilyn Ramenofsky
Dátum:2019
ISSN:0021-8375 2193-7206
Megjegyzések:White-crowned Sparrow (Zonotrichia leucophrys) populations of western North America exhibit dramatic differences in life history strategies including migration behavior. However, individual migration strategies and population-level migratory patterns remain largely unknown for this species. Here, we focused on the long-distance migratory subspecies, Gambel's White-crowned Sparrow (Zonotrichia leucophrys gambelii). We used ringing, tracking and stable hydrogen isotope (?2H) analysis of individuals migrating along the Pacific Flyway to assess individual phenology and routes as well as the pattern of connectivity between breeding and non-breeding sites. Results from all three methods, consisting of 79 ring recoveries, four light level geolocator tracks and 388 feather ?2H values, indicate low degrees of migratory connectivity. The isotope data provide evidence for leapfrog migration with the more southerly populations traveling greater distances to the breeding grounds than more centrally wintering individuals. Location estimates of four annual journeys revealed individually consistent migration strategies with relatively short flight bouts separated by two to three and two to six stopover sites during spring and autumn migration, respectively. However, combined results from all methods indicate high variability in migration distance among individuals. These findings confirm the phenotypic flexibility observed within this species and highlight the potential of White-crowned Sparrows for further investigations of evolutionary adaptations to ongoing changes in the environment.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
deuterium
light level geolocation
passerine migration
zonotrichia
leapfrog migration
migration detours
Megjelenés:Journal Of Ornithology. - 160 : 4 (2019), p. 1097-1107. -
További szerzők:Wingfield, John C. Krause, James E. Hobson, Keith A. Seavy, Nathaniel E. Gee, Jennifer Ramenofsky, Marilyn Németh Zoltán (1976-) (biológus)
Pályázati támogatás:NKFIH PD 121013, FK 124414
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5.

001-es BibID:BIBFORM081984
Első szerző:Wingfield, John C.
Cím:A mechanistic approach to understanding range shifts in a changing world : What makes a pioneer? / J. C. Wingfield, J. S. Krause, J. H. Perez, H. E. Chmura, Z. Németh, K. R. Word, R. M. Calisi, S. L. Meddle
Dátum:2015
ISSN:0016-6480
Megjegyzések:A species' range can be thought of as a manifestation of the ecological niche in space. Within a niche, evo-lution has resulted in traits that maximize fitness. Across millennia, natural oscillations in temperaturehave caused shifts in the geographic location of appropriate habitat and with corresponding changesin species' ranges. Contemporary climate change and human disturbance may lead to rapid range expan-sion or contractions with largely unknown consequences. Birds provide an excellent case study of thisphenomenon with some taxa expanding range and others contracting even to the point of extinction.What leads some populations to expand while others contract? Are there physiological and behavioralattributes of ♭♭pioneers" at the forefront of a range shift/expansion?The concept of allostasis provides a framework with which to begin to evaluate when a species will beable to successfully expand into new habitat. This tool allows the integration of normal energeticdemands (e.g. wear and tear of daily and seasonal routines) with novel challenges posed by unfamiliarand human altered environments. Allostasis is particularly attractive because it allows assessment ofhow individual phenotypes may respond differentially to changing environments. Here, we use allostasisto evaluate what characteristics of individuals and their environment permit successful range expansion.Understanding variation in the regulatory mechanisms that influence response to a novel environmentwill be fundamental for understanding the phenotypes of pioneers.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
climate change
Invasive species
Range expansion
Stress
Glucocorticoids
Allostasis
Megjelenés:General And Comparative Endocrinology. - 222 (2015), p. 44-53. -
További szerzők:Krause, J. S. Perez, Jonathan H. Chmura, Helen E. Németh Zoltán (1976-) (biológus) Word, Karen R. Calisi, Rebecca M. Meddle, Simone L.
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