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Item Effects of cell culture time and cytokines on migration of dental pulp stem cell-derived chondrogenic cells in collagen hydrogels(American Physiological Society, 2024-09-26) Yao, Li; Flynn, Nikol; Kaphle, PranitaThe transplantation of collagen hydrogels encapsulating human dental pulp stem cell (DPSC)-derived chondrogenic cells is potentially a novel approach for the regeneration of degenerated nucleus pulposus (NP) and cartilage. Grafted cell migration allows cells to disperse in the hydrogels and the treated tissue from the grafted location. We previously reported the cell migration in type I and type II hydrogels. It is important to explore further how cell culture time affect the cell motility. In this study, we observed the decreased motility of DPSC-derived chondrogenic cells after culturing for 2 weeks compared with cells cultured for 2 days in these gels. The Alamarblue assay showed the cell proliferation during the two-week cell culture period. The findings suggest that the transitions of cell motility and proliferation during the longer culture time. The result indicates that the early culture stage is an optimal time for cell transplantation. In a degenerated disc, the expression of IL-1β and TNFα increased significantly compared with healthy tissue and therefore may affect grafted cell migration. The incorporation of IL-1β and TNFα into the collagen hydrogels decreased cell motility. The study indicates that the control of IL-1β and TNFα production may help to maintain cell motility after transplantation. © 2024 The Author(s). Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.Item The Japanese climbing fern (Lygodium japonicum) invasion in the U.S.; insights from chloroplast genome sequencing(Pensoft Publishers, 2024-09-04) Markley, Morgan L.; Altergott, Ethan; Beck, James B.Japanese climbing fern (Lygodium japonicum) is a vine native to the open forests of eastern Asia that has become an invasive species in the U.S. Herbarium records first noted this species in the U.S. in 1903 (Georgia), with spread to eight states by the end of the 1930s and current establishment in 10 states of the southeastern U.S. We aimed to ask three questions regarding the introduction of L. japonicum: (1) Was there a single Japanese climbing fern introduction or were there multiple introductions? (2) What is the distribution of genotypes in the U.S.? and (3) What are the source population(s) from the native range in Asia? We sequenced the chloroplast genome from 74 L. japonicum herbarium specimens representing 24 native and 50 invasive range populations. Seventeen haplotypes were found in the native range compared to three in the invasive range. Our results indicate L. japonicum has low genotypic diversity in the invasive range relative to the native range. Even with low genotypic diversity, these data suggest at least three introductions of L. japonicum. However, we were unable to define the native source population(s) of invasive L. japonicum. © Morgan L. Markley et al. This is an open access article distributed under terms of the Creative Commons Attribution License (Attribution 4.0 International – CC BY 4.0).Item The combined effects of reactant kinetics and enzyme stability explain the temperature dependence of metabolic rates(John Wiley and Sons Ltd, 2017-04-23) DeLong, J.P.; Gibert, J.P.; Luhring, Thomas M.; Bachman, G.; Reed, B.; Neyer, A.; Montooth, K.L.A mechanistic understanding of the response of metabolic rate to temperature is essential for understanding thermal ecology and metabolic adaptation. Although the Arrhenius equation has been used to describe the effects of temperature on reaction rates and metabolic traits, it does not adequately describe two aspects of the thermal performance curve (TPC) for metabolic rate—that metabolic rate is a unimodal function of temperature often with maximal values in the biologically relevant temperature range and that activation energies are temperature dependent. We show that the temperature dependence of metabolic rate in ectotherms is well described by an enzyme-assisted Arrhenius (EAAR) model that accounts for the temperature-dependent contribution of enzymes to decreasing the activation energy required for reactions to occur. The model is mechanistically derived using the thermodynamic rules that govern protein stability. We contrast our model with other unimodal functions that also can be used to describe the temperature dependence of metabolic rate to show how the EAAR model provides an important advance over previous work. We fit the EAAR model to metabolic rate data for a variety of taxa to demonstrate the model's utility in describing metabolic rate TPCs while revealing significant differences in thermodynamic properties across species and acclimation temperatures. Our model advances our ability to understand the metabolic and ecological consequences of increases in the mean and variance of temperature associated with global climate change. In addition, the model suggests avenues by which organisms can acclimate and adapt to changing thermal environments. Furthermore, the parameters in the EAAR model generate links between organismal level performance and underlying molecular processes that can be tested for in future work. © 2017 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.Item Size-dependent predation and correlated life history traits alter eco-evolutionary dynamics and selection for faster individual growth(Springer Tokyo, 2018-03-05) DeLong, J.P.; Luhring, Thomas M.Age at maturation is a key life history trait influencing individual fitness, population age structure, and ecological interactions. We investigated the evolution of age at maturity through changes in the von Bertalanffy growth constant for organisms with a simple juvenile-adult life history. We used Gillespie eco-evolutionary models to uncover the role of predation in driving the evolution of the growth constant when eco-evolutionary dynamics are present. We incorporated both size-independent and size-dependent predation into our models to generate differences in selection and dynamics in the system. Our results generally support the idea that faster ontogenetic growth is beneficial when populations are growing but that predation tends to have little effect on age at maturity unless there are trade-offs with other life history traits. In particular, if faster ontogenetic growth comes at the cost of fecundity, our results suggest that predation selects for intermediate levels of growth and fecundity. Eco-evolutionary dynamics influenced the nature of selection only when growth was linked to fecundity. We also found that predators that increasingly consume larger prey tend to have higher population sizes due to the greater energy intake from larger prey, but the growth rate-fecundity trade-off reversed this pattern. Overall, our results suggest an important role for interactions between size-dependent foraging and life-history trade-offs in generating varying selection on age at maturity through underlying growth traits. © 2018, The Society of Population Ecology and Springer Japan KK, part of Springer Nature.Item Predators modify the temperature dependence of life-history trade-offs(John Wiley and Sons Ltd, 2018-09) Luhring, Thomas M.; Vavra, Janna M.; Cressler, Clayton E.; DeLong, J.P.Although life histories are shaped by temperature and predation, their joint influence on the interdependence of life-history traits is poorly understood. Shifts in one life-history trait often necessitate shifts in another-structured in some cases by trade-offs-leading to differing life-history strategies among environments. The offspring size-number trade-off connects three traits whereby a constant reproductive allocation (R) constrains how the number (O) and size (S) of offspring change. Increasing temperature and size-independent predation decrease size at and time to reproduction which can lower R through reduced time for resource accrual or size-constrained fecundity. We investigated how O, S, and R in a clonal population of Daphnia magna change across their first three clutches with temperature and size-independent predation risk. Early in ontogeny, increased temperature moved O and S along a trade-off curve (constant R) toward fewer larger offspring. Later in ontogeny, increased temperature reduced R in the no-predator treatment through disproportionate decreases in O relative to S. In the predation treatment, R likewise decreased at warmer temperatures but to a lesser degree and more readily traded off S for O whereby the third clutch showed a constant allocation strategy of O versus S with decreasing R. Ontogenetic shifts in S and O rotated in a counterclockwise fashion as temperature increased and more drastically under risk of predation. These results show that predation risk can alter the temperature dependence of traits and their interactions through trade-offs. © 2018 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.