bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fungal community shifts underpin declining mycelial production and turnover across a Pinus sylvestris chronosequence
Authors: Hagenbo Andreas , Kyaschenko Julia , Clemmensen Karina E. , Lindahl Björn D. , Fransson Petra 
Published: February 2018

Abstract

Fungi play critical roles in ecosystem processes such as decomposition and nutrient cycling, but have also been highlighted as significant contributors to organic matter build‐up in boreal forest soils. Ectomycorrhizal (ECM) mycelial biomass and necromass dynamics have recently been highlighted as essential for regulating build‐up of soil organic matter. Understanding the extent to which shifts in mycelial community or growth trait composition cause changes in mycelial production and turnover over ecological gradients would aid a mechanistic understanding of these important processes at an ecosystem scale.

Here, we test the hypotheses that shifting species and mycelial trait (exploration type) composition within the mycelial community underpin changes in biomass turnover with increasing forest age. We quantified mycelial turnover and assessed fungal community composition in a chronosequence of eight, 12‐ to 158‐year‐old, managed Pinus sylvestris forests. Turnover was estimated by determining mycelial biomass (ergosterol) in a sequence of ingrowth mesh bags and applying mathematical models. Fungal communities in the bags were identified using Pacific Biosciences sequencing of fungal ITS2 amplicons. To evaluate the accuracy of this method to represent all ECM fungi, community composition in bags was followed over time and compared with communities in soil.

Mycelial communities changed with stand age, but we found no evidence that there were concurrent shifts in mycelial exploration types. Forest age and turnover were significantly correlated with ECM mycelial community composition and collectively explained 39.4% of total variation. The similarity between fungal communities in mesh bags and in soil was strongly forest age dependent, with communities in mesh bags diverging from soil communities in stands older than 60 years. However, in all stands, when bag incubation time exceeded 75 days, communities became more similar to soil communities.

Synthesis. Our results support the idea that shifts in fungal community composition underpin the forest age‐related decrease in mycelial turnover; however, since ingrowth mesh bags exclude some mycorrhizal species in older forests, it remains a possibility that turnover estimates were not reflecting the entire community. While we found no evidence that mycelial exploration types of fungi changed systematically with forest age, we suggest that other traits that relate to biomass turnover and necromass degradation require further study, as they may explain the extent to which ectomycorrhizal fungi regulate and contribute to soil organic matter accumulation.
Association of ectomycorrhizal trees with high carbon‐to‐nitrogen ratio soils across temperate forests is driven by smaller nitrogen not larger carbon stocks
Authors: Zhu Kai , McCormack M. Luke , Lankau Richard A. , Egan J. Franklin , Wurzburger Nina 
Published: February 2018

Abstract

The distribution of mycorrhizal associations across biomes parallels a distinct gradient of soil carbon (C) and nitrogen (N) stocks, raising the question of how mycorrhizal traits relate to ecosystem properties. Arbuscular mycorrhizal (AM) and ectomycorrhizal (EM) hosts and fungi employ contrasting strategies for N acquisition, which may manifest in differences in soil C and N pools and/or soil C:N. However, cross‐biome comparisons are confounded with climatic and edaphic gradients as well as phylogenetic and functional trait distributions of component plant species. Here, we test emerging hypotheses that soil C, N and C:N are related to the dominance of EM trees within a temperate forest region where AM and EM trees largely coexist but vary in local abundance.

To determine the importance of mycorrhizal type on soil C and N, we analysed data from c. 1,000 forest inventory plots in the eastern United States. For each plot, we quantified the dominance of trees with different mycorrhizal associations and accounted for potentially confounding variables including phylogeny (angiosperm or gymnosperm), leaf N, soil clay content and climate. We used hierarchical Bayesian models to determine how these variables explained the patterns of soil C and N in the forest floor and mineral soil layers.

Increasing EM dominance was associated with higher C:N across all soil layers. This relationship remained even after accounting for tree phylogeny, leaf N content, soil clay content, temperature and precipitation, which were all important for explaining soil C:N. However, this mycorrhizal pattern of soil C:N was not related to increases in soil C content; rather, increasing EM dominance was associated with reductions in soil N.

Synthesis. Our findings are consistent with the proposition that mycorrhizal associations are related to terrestrial ecosystem properties. The mycorrhizal effect on soil C:N may result from differences in how arbuscular mycorrhizal and ectomycorrhizal plants interact with their fungal symbionts, decomposers and organic matter, to sustain differential cycling of C and N. Alternatively, these patterns could arise from differential success of the two mycorrhizal types in contrasting soil conditions; both processes may occur simultaneously, leading to a self‐reinforcing positive feedback.
Interactions among decaying leaf litter, root litter and soil organic matter vary with mycorrhizal type
Authors: Jacobs Luke M. , Sulman Benjamin N. , Brzostek Edward R. , Feighery John J. , Phillips Richard P. 
Published: February 2018

Abstract

Root‐derived inputs are increasingly viewed as primary controls of soil organic matter (SOM) formation; however, we have a limited understanding of how root decay rates depend on soil factors, and how decaying roots influence the breakdown of leaf litter and SOM.

We incubated root and leaf litter (alone and in combination) from arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) trees in soils collected from forest plots dominated by AM and ECM trees in a factorial design. In each microcosm, we quantified litter decay rates and the effects of decaying litters on soil C balance. We hypothesized that (1) AM root litters would decompose faster than ECM root litters, (2) root litter decay would be greatest when decomposed in “home” soils (e.g. AM litters in AM soils and ECM litters in ECM soils) and (3) root and leaf litters would decompose faster when decaying in the same microcosms than when decaying in separate microcosms, resulting in the largest CO2 losses.

Overall, AM root litter decomposed faster than ECM root litter, and the magnitude of this effect depended on soil origin. AM litters decayed fastest in AM soils, but ECM and mixed AM–ECM litters were unaffected by soil origin. Decaying roots increased leaf litter mass loss, but only in microcosms containing soils of the same origin (e.g. AM litters in AM soils; mixed litters in mixed soils).

Carbon losses were dominated by microbial respiration, and the magnitude of this flux depended on litter type and soil origin. When leaves and roots decayed together, respiratory losses exceeded those from microcosms containing leaves and roots alone, with the largest losses occurring in each litters' “home” soil. In AM soils, elevated losses were driven by roots accelerating leaf decay, while in ECM soils, elevated losses resulted from roots and leaves accelerating the decay of SOM; in mixed soils, root‐induced increases in leaf and SOM decay contributed to elevated C losses.

Synthesis. Our results suggest that root, leaf and SOM decay are intertwined, and that measurements of these processes in isolation may lead to incorrect estimates of the magnitude and source of C losses from soils.
From mycorrhizal fungal traits to ecosystem properties – and back again
Authors: Wurzburger Nina , Clemmensen Karina E. 
Published: February 2018

Abstract

Mycorrhizal fungi are known for their functional importance in plant growth and nutrition, and because these symbiotic fungi represent a fundamental linkage between plants and soils, they likely underpin a number of biogeochemical processes in ecosystems. However, our ability to isolate and quantify their role in ecosystems has remained a challenge.

This special feature presents seven new studies that advance our understanding of how mycorrhizal fungi contribute to ecosystem function. We specifically highlight two complementary approaches by which ecologists are gaining insight: focusing on mycorrhizal fungal traits to target the biological mechanisms that scale up to the ecosystem, and capturing patterns and processes across ecosystems to understand the net effect of complex plant–fungal–soil interactions.

The studies in our special feature provide evidence that traits both within and across species of mycorrhizal fungi can contribute to ecosystem processes, and that disturbance from global change and management may result in altered mycorrhizal traits and lead to compromised ecosystem function. From a broader perspective, studies also demonstrate that key ecosystem properties vary over gradients of mycorrhizal dominance and time, suggesting that mycorrhizal effects emerge from complex interactions within ecosystems

Synthesis. Employing complementary approaches to the study of mycorrhizal ecology may allow us to isolate the mycorrhizal traits that matter most for ecosystem properties, as well as the suite of ecosystem properties that result from mycorrhizal fungi, thus converging on biogeochemical mechanisms that underpin terrestrial ecosystem function.
Quantifying Magnitude of Group‐Level Differences in Patient Experiences with Health Care
Authors: Quigley Denise D. , Elliott Marc N. , Setodji Claude Messan , Hays Ron D. 
Published: February 2018

ObjectiveReview approaches assessing magnitude of differences in patient experience scores between different providers.Data Sources1990–2016 literature.Study DesignSystematic literature review.Data Extraction MethodsOf 812 articles mentioning “CAHPS,” “patient experience,” “patient satisfaction,” “important(ce),” “difference,” or “significance,” we identified 79 possible articles, yielding 35 for data abstraction. We included 22 articles measuring magnitude of differences in patient experiences.Principal FindingsWe identified three main ways of estimating magnitude of differences in patient experience scores: (1) by distribution/range of patient experience variable, (2) against external anchor, and (3) comparing a difference in patient experience on one covariate to differences in patient experience on other covariates.ConclusionsWe suggest routine estimation of magnitude in patient experience research. More work is needed documenting magnitude of differences between providers to make patient experience data more interpretable and usable.
Environmental variation shifts the relationship between trees and scatterhoarders along the continuum from mutualism to antagonism
Authors: SAWAYA Gina M. , GOLDBERG Adam S. , STEELE Michael A. , DALGLEISH Harmony J. 
Published: February 2018

ABSTRACTThe conditional mutualism between scatterhoarders and trees varies on a continuum from mutualism to antagonism and can change across time and space, and among species. We examined 4 tree species (red oak [Quercus rubra], white oak [Quercus alba], American chestnut [Castanea dentata] and hybrid chestnut [C. dentata × Castanea mollissima) across 5 sites and 3 years to quantify the variability in this conditional mutualism. We used a published model to compare the rates of seed emergence with and without burial to the probability that seeds will be cached and left uneaten by scatterhoarders to quantify variation in the conditional mutualism that can be explained by environmental variation among sites, years, species, and seed provenance within species. All species tested had increased emergence when buried. However, comparing benefits of burial to the probability of caching by scatterhoarders indicated a mutualism in red oak, while white oak was nearly always antagonistic. Chestnut was variable around the boundary between mutualism and antagonism, indicating a high degree of context dependence in the relationship with scatterhoarders. We found that different seed provenances did not vary in their potential for mutualism. Temperature did not explain microsite differences in seed emergence in any of the species tested. In hybrid chestnut only, emergence on the surface declined with soil moisture in the fall. By quantifying the variation in the conditional mutualism that was not caused by changes in scatterhoarder behavior, we show that environmental conditions and seed traits are an important and underappreciated component of the variation in the relationship between trees and scatterhoarders.
Cognition and the brain of brood parasitic cowbirds
Authors: SHERRY David F. , GUIGUENO Mélanie F. 
Published: February 2018

AbstractCowbirds are brood parasites. Females lay their eggs in the nests of other species, which then incubate the cowbird eggs and raise the young cowbirds. Finding and returning to heterospecific nests presents cowbirds with several cognitive challenges. In some species, such as brown‐headed cowbirds (Molothrus ater), females but not males search for and remember the locations of potential host nests. We describe recent research on sex differences in cognition and the hippocampus associated with this sex difference in search for host nests. Female brown‐headed cowbirds perform better than males on some, but not all, tests of spatial memory and females show a pattern of adult hippocampal neurogenesis not found in males or in closely related non‐parasitic birds. Because of the apparent specialization of the hippocampus, brown‐headed cowbirds may be a good model in which to examine spatial information processing in the avian hippocampus and we also describe recent research on the spatial response properties of brown‐headed cowbird hippocampal neurons.
Climate change, thermal niches, extinction risk and maternal‐effect rescue of toad‐headed lizards, Phrynocephalus, in thermal extremes of the Arabian Peninsula to the Qinghai—Tibetan Plateau
Authors: SINERVO Barry , MILES Donald B. , WU Yayong , MÉNDEZ‐DE LA CRUZ Fausto R. , KIRCHHOF Sebastian , QI Yin 
Published: February 2018

AbstractDetermining the susceptibility of species to changing thermal niches is a major goal for biologists. In this paper we develop an eco‐physiological model of extinction risk under climate change premised on behavioral thermoregulation. Our method downscales operative environmental temperatures, which restrict hours of activity of lizards, hr, for present‐day climate (1975) and future climate scenarios (2070). We apply our model using occurrence records of 20 Phrynocephalus lizards (or taxa in species complexes) drawn from literature and museum records. Our analysis is phylogenetically informed, because some clades may be more sensitive to rising temperatures. The limits for computed hr predict local extirpations among Phrynocephalus lizards at continental scales and delineate upper boundaries of thermal niches as defined by Extreme Value Distributions. Under the 8.5 Representative Concentration Pathway scenario, we predict extirpation of 64% of local populations by 2070 across 20 Phrynocephalus species, and 12 are at high risk of total extinction due to thermal limits being exceeded. In tandem with global strategies of lower CO2 emissions, we propose regional strategies for establishing new national parks to protect extinction‐prone taxa by preserving high‐elevation climate refugia within existing sites of species occurrence. We propose that evolved acclimatization — maternal plasticity — may ameliorate risk, but is poorly studied. Previous studies revealed that adaptive maternal plasticity by thermoregulating gravid females alter progeny thermal preferences by ±1 °C. We describe plasticity studies for extinction‐prone species that could assess whether they might be buffered from climate warming — a self‐rescue. We discuss an epigenetic framework for studying such maternal‐effect evolution.
Effects of rodent abundance and richness on cache pilfering
Authors: DITTEL Jacob W. , VANDER WALL Stephen B. 
Published: February 2018

AbstractScatterhoarding is a common behavioral strategy to conserve food during periods of scarcity, but this type of food storage is vulnerable to theft or pilferage. A variety of environmental factors and cache characteristics influence the rate of pilferage. Here we investigate 2 environmental factors, which heretofore have not received much attention: the abundance and species richness of scatterhoarding animals in the vicinity of scatterhoarded seeds. We measured the rate of cache pilferage at 7 sites that differed in the number and species composition of granivorous rodents in western Nevada using local native seeds and sunflower seeds. We found that there was no difference between the pilferage rate of native seeds and sunflower seeds, but that sites with different rodent abundances had different pilferage rates. Pilferage rates were proportional to the abundance of scatterhoarding rodents. Scatterhoarding rodents removed seeds at the rate of 1.3%/day/rodent individual. Species richness of scatterhoarding rodents was not correlated with rates of pilferage. These results suggest that density‐dependent competition for scatterhoarded seeds is a strong determinant of pilferage rates.
Lectin Isolated from Japanese Red Sword Beans (Canavalia gladiata) as a Potential Cancer Chemopreventive Agent
Authors: Une Satsuki , Nonaka Koji , Akiyama Junich 
Published: February 2018

AbstractIn this study, we investigated the chemical and biological profile of lectin isolated from Japanese red sword beans (Canavalia gladiata; RSBs). RSB lectin was purified using maltamyl‐Sepharose 4B and subjected to amino acid composition and partial amino acid sequencing analyses, and evaluated for blood and carbohydrate specificity, mitogenic activity, splenic natural killer (NK) cell activity, and its effect on B16 melanoma cell proliferation, compared with Concanavalin A (Con A). The amino acid composition and sequences of RSB lectin were similar to those of Con A. RSB lectin showed specificity to mannose, glucose, maltose, methyl‐D‐mannoside, and thyroglobulin, but not rhamnose, using mouse, sheep, and rabbit erythrocytes. Compared with Con A, RSB lectin showed low resistance to proteases and to temperatures greater than 70 °C, but high mitogenic activity for mouse splenic cells. Notably, while treatment with RSB lectin and Con A (0.01 and 0.1 μg/mL) promoted similar levels of splenic NK cell activity, which were higher than that observed in the control (0 μg/mL) and interleukin 2 (IL‐2) (25 U)‐treated populations, RBS lectin exerted a significantly stronger anti‐proliferative effect than Con A at a concentration of 125.0 μg per well. Overall, our results show that RSB lectin might exert immunological effects on mouse splenic cells and could thus be used as a potential cancer chemopreventive agent.Practical ApplicationJapanese red sword bean (RSB) is a tropical perennial legume consumed in many Asian countries. RSB lectin shows specificity to mannose, glucose, maltose, methyl‐d‐mannoside, and thyroglobulin, but not to rhamnose, using mouse, sheep, and rabbit erythrocytes. RSB lectin exhibits similarities to Concanavalin A in amino acid composition and sequence, shows mitogenic activity for mouse splenic cells and strong anti‐proliferative activity for B16 melanoma cells, and also enhances the activity of splenic natural killer (NK) cells against YAC‐1 cells. Thus, RSB lectin has the potential to be used as a bioactive protein in medical research.
Prediction of Firmness and pH for “Golden Delicious” Apple Based on Elasticity Index from Modal Analysis
Authors: Hou Jumin , Zhang Yuxia , Sun Yonghai , Xu Na , Leng Yue 
Published: February 2018

AbstractAn experimental modal test system was established to extract the natural frequencies of “Golden Delicious” apple, after which the elasticity index was calculated to predict the apple quality parameters based on the orthogonal polynomials method. The elasticity index in every vibration mode changed dramatically (P = 0.01) along time revolution. The multivariate regression methods were used to model the predictive relationship between the elasticity index and the apple quality parameters. The models of the apple juice pH based on support vector regression presented adequate determination coefficients of calibration set (Q2 = 0.68) and prediction set (R2 = 0.55), respectively. The models based on partial least squares regression could be used for predicting the apple firmness parameter offset gradient (Q2 = 0.76 andR2 = 0.72). It helped understanding the fruit dynamic properties of the fruit and spontaneously obtaining the fruit chemical parameters. A nondestructive and portable device was viable for fruit quality estimation by the modal test system during storage, transport, and even growth on the tree.Practical ApplicationA nondestructive and portable device was provided for fruit quality detection during storage, transport and even growth based on experimental modal analysis. A systematic statistical analysis method about outlier detection, data set partitioning, parameter optimization, and multiple regression models were provided.
Effects of Pulsatile Blood Flow on Oxygenator Performance
Authors: Schraven Lotte , Kaesler Andreas , Flege Christian , Kopp Rüdger , Schmitz‐Rode Thomas , Steinseifer Ulrich , Arens Jutta 
Published: February 2018

AbstractExtracorporeal membrane oxygenation (ECMO) is mainly used for the therapy of acute respiratory distress syndrome and chronic obstructive lung disease. In the last years, the development of these systems underwent huge steps in optimization, but there are still problems with thrombus formation, clogging, and thus insufficient gas exchange. One idea of ECMO optimization is a pulsatile blood flow through the oxygenator, but this is still a controversy discussion. Analyzing available publications, it was not possible to identify a general statement about the effect of pulsatile blood flow on the gas exchange performance. The variety of parameters and circuit components have such a high influence on the outcome that a direct comparison of the studies is difficult. For this reason, we performed a structured study to evaluate the effects of pulsatile blood flow on the gas exchange performance of oxygenator. In in vitro tests according to DIN EN ISO 7199, we tested a small oxygenator (0.25 m2 exchange surface, polymethylpentene fibers, 33 mL priming volume) with constant and pulsatile blood flow in comparison. Therefore, we varied the mean blood flow from 250 to 1200 mL/min, the amplitude of 0, 20, and 50%, and the frequency of 30, 60, and 90 bpm. The results demonstrate that the gas transfer for pulsatile and constant blood flow was similar (oxygen: 36–64 mLO2/LBlood; carbon dioxide 35–80 mLCO2/LBlood) for the same mean blood flow ranges. Over all, the results and analyses showed a statistically nonsignificant difference between pulsatile and nonpulsatile flow. Consequently, we conclude that the implementation of pulsatile blood flow has only a small to no effect on the gas exchange performance in an oxygenator. As the results were obtained using an oxygenator with a coiled fiber bundle, the test must be verified for a stacked fiber oxygenator.