scholarly journals Fluctuating feather asymmetry in relation to corticosterone levels is sex-dependent in Eurasian treecreeper ( Certhia familiaris ) nestlings

2010 ◽  
Vol 6 (4) ◽  
pp. 521-524 ◽  
Author(s):  
Samuli Helle ◽  
Petri Suorsa ◽  
Esa Huhta ◽  
Harri Hakkarainen
Keyword(s):  
Plasma Levels ◽  
Developmental Trajectory ◽  
Stress Hormone ◽  
Vertebrate Species ◽  
Free Living ◽  
Phenotypic Marker ◽  
Individual Level ◽  
Certhia Familiaris ◽  
Specific Association ◽  
Eurasian Treecreeper

Fluctuating asymmetry (FA) has been widely used as a stress-related phenotypic marker of developmental instability. However, previous studies relating FA to various stressful conditions have produced inconsistent results and we still lack quantitative individual-level evidence that high FA is related to stress in wild vertebrate species. We studied how baseline plasma levels of corticosterone predicted FA of wing and tail feathers in free-living Eurasian treecreeper ( Certhia familiaris ) nestlings. We found a sex-specific association between corticosterone levels and FA: high corticosterone levels were related to an increased FA in male but not in female nestlings. These results suggest that in treecreepers, FA may correlate with individual stress hormone levels, male developmental trajectory being potentially more sensitive to stress than that of the female.

Prey depletion by the foraging of the Eurasian treecreeper, Certhia familiaris, on tree-trunk arthropods

Oecologia ◽  
2001 ◽  
Vol 128 (4) ◽  
pp. 488-491 ◽  
Author(s):  
Ari Jäntti ◽  
Teija Aho ◽  
Harri Hakkarainen ◽  
Markku Kuitunen ◽  
Jukka Suhonen
Keyword(s):  
Tree Trunk ◽  
Certhia Familiaris ◽  
Eurasian Treecreeper ◽  
Prey Depletion

Validity of combining heart rate and uniaxial acceleration to measure free-living physical activity energy expenditure in young men

2012 ◽  
Vol 113 (11) ◽  
pp. 1763-1771 ◽  
Author(s):  
C. Villars ◽  
A. Bergouignan ◽  
J. Dugas ◽  
E. Antoun ◽  
D. A. Schoeller ◽  
...  
Keyword(s):  
Heart Rate ◽  
Energy Expenditure ◽  
Intraclass Correlation ◽  
Tolerance Test ◽  
Free Living ◽  
Individual Level ◽  
Individual Calibration ◽  
Old Men ◽  
Activity Energy ◽  
Free Living Conditions

Combining accelerometry (ACC) with heart rate (HR) monitoring is thought to improve activity energy expenditure (AEE) estimations compared with ACC alone to evaluate the validity of ACC and HR used alone or combined. The purpose of this study was to estimate AEE in free-living conditions compared with doubly labeled water (DLW). Ten-day free-living AEE was measured by a DLW protocol in 35 18- to 55-yr-old men (11 lean active; 12 lean sedentary; 12 overweight sedentary) wearing an Actiheart (combining ACC and HR) and a RT3 accelerometer. AEE was estimated using group or individual calibration of the HR/AEE relationship, based on an exercise-tolerance test. In a subset ( n = 21), AEE changes (ΔAEE) were measured after 1 mo of detraining (active subjects) or an 8-wk training (sedentary subjects). Actiheart-combined ACC/HR estimates were more accurate than estimates from HR or ACC alone. Accuracy of the Actiheart group-calibrated ACC/HR estimates was modest [intraclass correlation coefficient (ICC) = 0.62], with no bias but high root mean square error (RMSE) and limits of agreement (LOA). The mean bias of the estimates was reduced by one-third, like RMSE and LOA, by individual calibration (ICC = 0.81). Contrasting with group-calibrated estimates, the Actiheart individual-calibrated ACC/HR estimates explained 40% of the variance of the DLW-ΔAEE (ICC = 0.63). This study supports a good level of agreement between the Actiheart ACC/HR estimates and DLW-measured AEE in lean and overweight men with varying fitness levels. Individual calibration of the HR/AEE relationship is necessary for AEE estimations at an individual level rather than at group scale and for ΔAEE evaluation.

scholarly journals Flatworm-specific transcriptional regulators promote the specification of tegumental progenitors in Schistosoma mansoni

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
George R Wendt ◽  
Julie NR Collins ◽  
Jimin Pei ◽  
Mark S Pearson ◽  
Hayley M Bennett ◽  
...  
Keyword(s):  
Stem Cells ◽  
Zinc Finger ◽  
Broad Spectrum ◽  
Transcriptional Regulators ◽  
Vertebrate Species ◽  
Outer Coat ◽  
Free Living ◽  
Cell Specification ◽  
Tegumental Cell

Schistosomes infect more than 200 million people. These parasitic flatworms rely on a syncytial outer coat called the tegument to survive within the vasculature of their host. Although the tegument is pivotal for their survival, little is known about maintenance of this tissue during the decades schistosomes survive in the bloodstream. Here, we demonstrate that the tegument relies on stem cells (neoblasts) to specify fusogenic progenitors that replace tegumental cells lost to turnover. Molecular characterization of neoblasts and tegumental progenitors led to the discovery of two flatworm-specific zinc finger proteins that are essential for tegumental cell specification. These proteins are homologous to a protein essential for neoblast-driven epidermal maintenance in free-living flatworms. Therefore, we speculate that related parasites (i.e., tapeworms and flukes) employ similar strategies to control tegumental maintenance. Since parasitic flatworms infect every vertebrate species, understanding neoblast-driven tegumental maintenance could identify broad-spectrum therapeutics to fight diseases caused by these parasites.

scholarly journals Longitudinal Change in Adolescent Bedtimes Measured by Self-Report and Actigraphy

2019 ◽  
Vol 2 (4) ◽  
pp. 282-287 ◽  
Author(s):  
Robert J. Brychta ◽  
Vaka Rögnvaldsdóttir ◽  
Sigríður L. Guðmundsdóttir ◽  
Rúna Stefánsdóttir ◽  
Soffia M. Hrafnkelsdóttir ◽  
...  
Keyword(s):  
Self Report ◽  
Longitudinal Change ◽  
Group Level ◽  
Sensitivity To Change ◽  
Free Living ◽  
Individual Level ◽  
Level Change ◽  
Report Bias ◽  
Wrist Actigraphy ◽  
Adolescent Sleep

Introduction: Sleep is often quantified using self-report or actigraphy. Self-report is practical and less technically challenging, but prone to bias. We sought to determine whether these methods have comparable sensitivity to measure longitudinal changes in adolescent bedtimes. Methods: We measured one week of free-living sleep with wrist actigraphy and usual bedtime on school nights and non-school nights with self-report questionnaire in 144 students at 15 y and 17 y. Results: Self-reported and actigraphy-measured bedtimes were correlated with one another at 15 y and 17 y (p < .001), but reported bedtime was consistently earlier (>30 minutes, p < .001) and with wide inter-method confidence intervals (> ±106 minutes). Mean inter-method discrepancy did not differ on school nights at 15 y and 17 y but was greater at 17 y on non-school nights (p = .002). Inter-method discrepancy at 15 y was not correlated to that at 17 y. Mean change in self-reported school night bedtime from 15 y to 17 y did not differ from that by actigraphy, but self-reported bedtime changed less on non-school nights (p = .002). Two-year changes in self-reported bedtime did not correlate with changes measured by actigraphy. Conclusions: Although methods were correlated, consistently earlier self-reported bedtime suggests report-bias. More varied non-school night bedtimes challenge the accuracy of self-report and actigraphy, reducing sensitivity to change. On school nights, the methods did not differ in group-level sensitivity to changes in bedtime. However, lack of correlation between bedtime changes by each method suggests sensitivity to individual-level change was different. Methodological differences in sensitivity to individual- and group-level change should be considered in longitudinal studies of adolescent sleep patterns.

scholarly journals Resource acquisition and allocation traits in symbiotic rhizobia with implications for life-history outside of legume hosts

2018 ◽  
Vol 5 (12) ◽  
pp. 181124 ◽  
Author(s):  
Katherine E. Muller ◽  
R. Ford Denison
Keyword(s):  
Root Nodules ◽  
Natural Populations ◽  
Heritable Variation ◽  
Free Living ◽  
Term Survival ◽  
Individual Level ◽  
Dividing Cells ◽  
Term Functions ◽  
Microbial Symbionts

Resources that microbial symbionts obtain from hosts may enhance fitness during free-living stages when resources are comparatively scarce. For rhizobia in legume root nodules, diverting resources from nitrogen fixation to polyhydroxybutyrate (PHB) has been discussed as a source of host–symbiont conflict. Yet, little is known about natural variation in PHB storage and its implications for rhizobial evolution. We therefore measured phenotypic variation in natural rhizobia populations and investigated how PHB might contribute to fitness in the free-living stage. We found that natural populations of rhizobia from Glycine max and Chamaecrista fasciculata had substantial, heritable variation in PHB acquisition during symbiosis. A model simulating temperature-dependent metabolic activity showed that the observed range of stored PHB per cell could support survival for a few days, for active cells, or over a century for sufficiently dormant cells. Experiments with field-isolated Bradyrhizobium in starvation culture suggest PHB is partitioned asymmetrically in dividing cells, consistent with individual-level bet-hedging previously demonstrated in E. meliloti . High-PHB isolates used more PHB over the first month, yet still retained more PHB for potential long-term survival in a dormant state. These results suggest that stored resources like PHB may support both short-term and long-term functions that contribute to fitness in the free-living stage.

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