Találati lista | Tudóstér

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.
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
Borító:
Saját polcon:

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
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
Borító:
Saját polcon:

001-es BibID:	BIBFORM121432
Első szerző:	Ramenofsky, Marilyn
Cím:	Comparison of the Phenotypic Flexibility of Muscle and Body Condition of Migrant and Resident White-Crowned Sparrows / Marilyn Ramenofsky, Andrew W. Campion, Darren T. Hwee, Stacy K. Wood, Jesse S. Krause, Zoltán Németh, Jonathan H. Pérez, Sue Bodine
Dátum:	2024
ISSN:	2993-7965 2993-7973
Megjegyzések:	Seasonally breeding birds express variations of traits (phenotypic flexibility) throughout their life history stages that represent adaptations to environmental conditions. Changes of body condition during migration have been well studied, whereas alterations of skeletal and cardiac muscles, body mass, and fat scores have yet to be characterized throughout the spring or fall migratory stages. Additionally, we examined flexible patterns of muscle, body mass, and fat score in migrant white-crowned sparrows (Zonotrichia leucophrys gambelii) in comparison with those in a resident subspecies (Zonotrichia leucophrys nuttalli) during the stages they share to evaluate the influence of different life histories. Migrants showed hypertrophy of the pectoralis muscle fiber area on the wintering grounds in late prealternate molt, yet increased pectoralis muscle mass was not detected until birds readied for spring departure. While pectoralis profile and fat scores enlarged at predeparture in spring and fall, pectoralis, cardiac, and body masses were greater only in spring stages, suggesting seasonal differences for migratory preparation. Gastrocnemius mass showed little change throughout all stages, whereas gastrocnemius fiber area declined steadily but rebounded in fall on the wintering grounds, where migrants become more sedentary. In general, residents are heavier birds with larger leg structures, while migrants sport longer wings and greater heart mass. Phenotypic flexibility was most prominent among residents with peaks of pectoralis, gastrocnemius, and body masses during the winter stage, when local weather is most severe. Thus, the subspecies express specific patterns of phenotypic flexibility with peaks coinciding with the stages of heightened energy demands: the winter stage for residents and the spring stages for migrants.
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk white-crowned sparrow phenotypic flexibility migrant resident skeletal muscle cardiac muscle muscle fiber hypertrophy allopatry
Megjelenés:	Ecological and Evolutionary Physiology. - 97 : 1 (2024), p. 11-28. -
További szerzők:	Campion, Andrew W. Hwee, Darren T. Wood, Stacy K. Krause, Jesse S. Németh Zoltán (1976-) (biológus) Pérez, Jonathan H. Bodine, Sue
Pályázati támogatás:	FK 124414 NKFIH ÚNKP-21-5 Egyéb
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
Borító:
Saját polcon:

001-es BibID:	BIBFORM107663
035-os BibID:	(WOS)000397620100028 (Scopus)85016594854 (PUBMED)28183869
Első szerző:	Ramenofsky, Marilyn
Cím:	Behavioral and physiological traits of migrant and resident white-crowned sparrows: a common garden approach / Marilyn Ramenofsky, Andrew W. Campion , Jonathan H. Pérez, Jesse S. Krause, Zoltán Németh
Dátum:	2017
ISSN:	0022-0949
Megjegyzések:	To accommodate a migratory life history, migrants express a greater number of physiological and behavioral stages per annum than residents and are thus considered to have higher finite state diversity (FSD). To investigate the physiological mechanisms and constraints associated with migration, direct comparison of two subspecies of white-crowned sparrow - migrant, Zonotrichia leucophrys gambelii, and resident, Z. l. nuttalli - were made under common garden conditions of photoperiod and housing, as birds progressed from winter through the vernal life history stages. We tested the hypothesis that migrants (higher FSD) respond differently than residents (lower FSD) to the initial predictive cue, photoperiod, to initiate and integrate the progression of vernal stages of prenuptial molt, migration and development of breeding. If differences in vernal phenology were noted, then the basis for the distinctions was considered genetic. Results indicate that (1) residents had a lower threshold to vernal photoperiod with elevations of plasma androgen, growth and development of reproductive structures preceding those of migrants; (2) only migrants displayed prenuptial molt, preparations for migration and migratory restlessness; and (3) neither baseline nor stress-induced plasma corticosterone differed across subspecies, suggesting energetic demands of the common garden were insufficient to induce a differential adrenocortical response in either subspecies, highlighting the impact of environmental conditions on corticosterone secretion. Thus, in a common garden experiment, Z. l. gambelii responds differently to the initial predictive cue, photoperiod, to initiate and execute the vernal stages of molt, migration and development of breeding in comparison to the shared stage of breeding with Z. l. nuttalli, confirming a genetic basis for the subspecies differences
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk Finite state diversity Flight muscle hypertrophy Migratory restlessness Prenuptial molt Androgens Corticosterone
Megjelenés:	Journal Of Experimental Biology. - 220 : 7 (2017), p. 1330-1340. -
További szerzők:	Campion, Andrew W. Pérez, Jonathan H. Krause, Jesse S. Németh Zoltán (1976-) (biológus)
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
Borító:
Saját polcon: