bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spatially extended forward suppression in primate auditory cortex
Authors: Zhou Yi , Wang Xiaoqin 
Published: December 2013

AbstractWhen auditory neurons are stimulated with a pair of sounds, the preceding sound can inhibit the neural responses to the succeeding sound. This phenomenon, referred to as ‘forward suppression’, has been linked to perceptual forward masking. Previous studies investigating forward suppression typically measured the interaction between masker and probe sounds using a fixed sound location. However, in natural environments, interacting sounds often come from different spatial locations. The present study investigated two questions regarding forward suppression in the primary auditory cortex and adjacent caudal field of awake marmoset monkeys. First, what is the relationship between the location of a masker and its effectiveness in inhibiting neural response to a probe? Second, does varying the location of a masker change the spectral profile of forward suppression? We found that a masker can inhibit a neuron's response to a probe located at a preferred location even when the masker is located at a non‐preferred location of a neuron. This is especially so for neurons in the caudal field. Furthermore, we found that the strongest forward suppression is observed when a masker's frequency is close to the best frequency of a neuron, regardless of the location of the masker. These results reveal, for the first time, the stability of forward masking in cortical processing of multiple sounds presented from different locations. They suggest that forward suppression in the auditory cortex is spectrally specific and spatially broad with respect to the frequency and location of the masker, respectively.
Intact brown adipose tissue thermogenesis is required for restorative sleep responses after sleep loss
Authors: Szentirmai Éva , Kapás Levente 
Published: December 2013

AbstractMetabolic signals related to feeding and body temperature regulation have profound effects on vigilance. Brown adipose tissue (BAT) is a key effector organ in the regulation of metabolism in several species, including rats and mice. Significant amounts of active BAT are also present throughout adulthood in humans. The metabolic activity of BAT is due to the tissue‐specific presence of the uncoupling protein‐1 (UCP‐1). To test the involvement of BAT thermogenesis in sleep regulation, we investigated the effects of two sleep‐promoting stimuli in UCP‐1‐deficient mice. Sleep deprivation by gentle handling increased UCP‐1 mRNA expression in BAT and elicited rebound increases in non‐rapid‐eye‐movement sleep and rapid‐eye‐movement sleep accompanied by elevated slow‐wave activity of the electroencephalogram. The rebound sleep increases were significantly attenuated, by ~ 35–45%, in UCP‐1‐knockout (KO) mice. Wild‐type (WT) mice with capsaicin‐induced sensory denervation of the interscapular BAT pads showed similar impairments in restorative sleep responses after sleep deprivation, suggesting a role of neuronal sleep‐promoting signaling from the BAT. Exposure of WT mice to 35 °C ambient temperature for 5 days led to increased sleep and body temperature and suppressed feeding and energy expenditure. Sleep increases in the warm environment were significantly suppressed, by ~ 50%, in UCP‐1‐KO animals while their food intake and energy expenditure did not differ from those of the WTs. These results suggest that the metabolic activity of the BAT plays a role in generating a metabolic environment that is permissive for optimal sleep. Impaired BAT function may be a common underlying cause of sleep insufficiency and metabolic disorders.
Herbivory makes major contributions to ecosystem carbon and nutrient cycling in tropical forests
Authors: Metcalfe Daniel B. , Asner Gregory P. , Martin Roberta E. , Silva Espejo Javier E. , Huasco Walter Huaraca , Farfán Amézquita Felix F. , Carranza‐Jimenez Loreli , Galiano Cabrera Darcy F. , Baca Liliana Durand , Sinca Felipe , Huaraca Quispe Lidia P. , Taype Ivonne Alzamora , Mora Luzmila Eguiluz , Dávila Angela Rozas , Solórzano Marlene Mamani , Puma Vilca Beisit L. , Laupa Román Judith M. , Guerra Bustios Patricia C. , Revilla Norma Salinas , Tupayachi Raul , Girardin Cécile A. J. , Doughty Christopher E. , Malhi Yadvinder 
Published: December 2013

AbstractThe functional role of herbivores in tropical rainforests remains poorly understood. We quantified the magnitude of, and underlying controls on, carbon, nitrogen and phosphorus cycled by invertebrate herbivory along a 2800 m elevational gradient in the tropical Andes spanning 12°C mean annual temperature. We find, firstly, that leaf area loss is greater at warmer sites with lower foliar phosphorus, and secondly, that the estimated herbivore‐mediated flux of foliar nitrogen and phosphorus from plants to soil via leaf area loss is similar to, or greater than, other major sources of these nutrients in tropical forests. Finally, we estimate that herbivores consume a significant portion of plant carbon, potentially causing major shifts in the pattern of plant and soil carbon cycling. We conclude that future shifts in herbivore abundance and activity as a result of environmental change could have major impacts on soil fertility and ecosystem carbon sequestration in tropical forests.
The microtubule associated protein tau H1 haplotype and risk of essential tremor
Authors: Clark L. N. , Liu X. , Parmalee N. L. , Hernandez N. , Louis E. D. 
Published: December 2013

Background and purposeTwo recent studies investigated the association of the microtubule associated protein tau (MAPT) H1 haplotype, a known risk factor for neurodegenerative disease including progressive supranuclear palsy and Parkinson's disease (PD), with essential tremor (ET).MethodsTo confirm this association in a different population the distribution of allele and genotype frequencies for the MAPT H1/H2 tagging single‐nucleotide polymorphism (SNP) rs1052553 in ET cases and controls enrolled in a clinical‐epidemiological study of ET at Columbia University was analyzed.ResultsOverall, no association was observed between ET and the MAPT H1 haplotype. The analysis was also restricted to clinical subtypes including early‐onset (≤40 years of age), Ashkenazi Jewish ancestry, white non‐Ashkenazi, or ET cases with a ‘definite’ or ‘probable/possible’ diagnosis; none of these stratified analyses showed evidence of association with ET. A meta‐analysis of the H1/H2 tagging SNP rs1052553 in published data sets and the H1 haplotype with risk for ET in the current study was also performed and did not find evidence for association.ConclusionsThe inconsistent reports of association of MAPT H1 in three emerging studies (our own and two published studies) may reflect sampling issues and/or clinical heterogeneity in these populations.
Cerebrospinal fluid biomarkers of β‐amyloid metabolism and neuronal damage in epileptic seizures
Authors: Shahim P. , Rejdak R. , Ksiazek P. , Blennow K. , Zetterberg H. , Mattsson N. , Rejdak K. 
Published: December 2013

Background and purposeThe main objectives of this study were to investigate if epileptic seizures have effects on brain metabolism of β‐amyloid (Aβ), as reflected by cerebrospinal fluid (CSF) levels of different isoforms of Aβ peptides and soluble amyloid precursor protein (APP), and neuronal degeneration, as reflected by CSF biomarker signs of acute neuronal injury.MethodsForty‐five patients were included, 21 of whom had single generalized tonic‐clonic seizures sGTCS), 11 had repetitive GTCS, 7 had repetitive partial seizures (rPS), 6 had single partial seizure (sPS) and 4 fulfilled the criterion for non‐convulsive status epilepticus (nSE). CSF was analyzed for Aβx‐38, Aβx‐40, Aβx‐42, Aβ1‐42, soluble APP fragments (sAPP‐α/β), total‐tau (T‐tau) and phosphorylated tau (P‐tau), as well as heart‐type fatty acid binding protein (H‐FABP).ResultsPatients with seizures had decreased levels of T‐tau (P = 0.0016) and P‐tau (P = 0.0028) compared with controls, but no differences in H‐FABP (P = 0.67). There were no overall differences in Aβ or sAPP peptides between seizure patients and controls. In patients with rPS, the levels of Aβx‐38 and Aβx‐40 were elevated compared with nSE (P < 0.01), sPS (P < 0.05) and controls (P < 0.05), and Aβx‐42 was elevated in rPS relative to nSE (P < 0.05).ConclusionsThe findings of this study argue against acute neuronal injury following medically treated seizures but suggest that seizures may reduce CSF levels of tau. Although seizures generally did not affect CSF levels of Aβ or sAPP peptides, our findings suggest that different types of seizures may have different effects on APP metabolism.
DegP primarily functions as a protease for the biogenesis of β‐barrel outer membrane proteins in the Gram‐negative bacterium Escherichia coli
Authors: Ge Xi , Wang Rui , Ma Jing , Liu Yang , Ezemaduka Anastasia N. , Chen Peng R. , Fu Xinmiao , Chang Zengyi 
Published: December 2013

DegP (also designated as HtrA) and its homologs are found in prokaryotic cells and such eukaryotic organelles as mitochondria and chloroplasts. DegP has been found to be essential for the growth of Gram‐negative bacteria under heat shock conditions and arguably considered to possess both protease and chaperone activities. The function of DegP has not been clearly defined. Using genetically incorporated non‐natural amino acids as photo‐crosslinkers, here we identified the β‐barrel outer membrane proteins (OMPs) as the major natural substrates of DegP in Escherichia coli cells. We also demonstrated that DegP primarily functions as a protease, at both low and high temperatures, to eliminate unfolded OMPs, with hardly any appreciable chaperone activity in cells. We also found that the toxic and cell membrane‐damaging misfolded OMPs would accumulate in DegP‐lacking cells cultured under heat shock conditions. Together, our study defines the primary function of DegP in OMP biogenesis and offers a mechanistic insight into the essentiality of DegP for cell growth under heat shock conditions.Structured digital abstract

DegP physically interacts with ompA by pull down (1, 2)

DegP physically interacts with ompX, ompA, ompW, ompF, nmpC and ompC by pull down (View interaction)

DegP physically interacts with ompC and ompF by pull down (View interaction)

DegP physically interacts with ompC and ompA by pull down (View interaction)

DegP physically interacts with ompC, malE, fkpA, ompW, ompA, ompF, nmpC and ompX by cross-linking study (View interaction)
Detrital nutrient content determines growth rate and elemental composition of bromeliad‐dwelling insects
Authors: González Angélica L. , Romero Gustavo Q. , Srivastava Diane S. 
Published: December 2013

Summary

In many aquatic ecosystems, detritus is the main basal resource and is able to support highly productive food webs. However, detritus is a relatively poor‐quality resource compared with living plants. Despite substantial research on how the nutrient content of living plants limits herbivores, there is little information on whether the nitrogen (N) and/or phosphorus (P) content of plant detritus similarly limits detritivore performance, especially under natural conditions.

We examined this question by rearing larval chironomids and caddisflies within detrital‐based tank‐bromeliad ecosystems on different food qualities. We manipulated detrital nutrient content by increasing N and P simultaneously or separately.

Chironomids and caddisflies showed faster growth rates when they fed on enriched detritus. Both N and P contents of the detritus limited the growth of chironomids, but combined effects were antagonistic (i.e. growth rates were less than expected according to single additions of N or P). By contrast, the growth of caddisflies was greater when fed on N‐rich detritus, but was unaffected by P enrichment. These results suggest that under natural conditions, chironomids and caddisflies show reduced growth rates because they face strong nutrient limitation.

We also found that increased growth rates were correlated with an increase in the body P content of chironomids and caddisflies, which is consistent with the growth rate hypothesis. This hypothesis predicts that high body P content permits the rapid ribosomal RNA production needed for high growth rates. This study therefore provides some of the first direct evidence for the growth rate hypothesis in detrital systems. Although detritus quality was an important factor determining the growth of detritivores, it had no effect on the survival of these insects.

Our study highlights the importance of N and P additions as well as their interaction in constraining the growth of different consumers. Our findings point to the need for future studies integrating organism life history traits and ecological stoichiometry to better understand how food quality affects the functioning of detritus‐based ecosystems.
Phylogeography of noble crayfish (Astacus astacus) reveals multiple refugia
Authors: Schrimpf Anne , Theissinger Kathrin , Dahlem Jenifer , Maguire Ivana , Pârvulescu Lucian , Schulz Holger K. , Schulz Ralf 
Published: December 2013

Summary

Reconstructing the phylogeographic history of a species can aid in defining areas of conservation priority. For freshwater species, historical river structure plays a significant role in explaining genetic differentiation and population structure. However, human‐induced translocations can erase the natural genetic structure, especially for species of commercial interest such as the noble crayfish (Astacus astacus).

Our aim was to reconstruct the current genetic structure of the endangered noble crayfish in central Europe to identify refugial areas that are hotspots of genetic diversity. We analysed a fragment of the mitochondrial cytochrome oxidase subunit I, and the 16S rRNA from 540 noble crayfish specimens from 156 sampling sites distributed around five European sea basins. Additionally, we conducted a microsatellite analysis of 289 individuals from 22 sites.

Both mitochondrial and nuclear markers revealed genetically relatively homogenous populations in central Europe that had been influenced by anthropogenic translocations. However, some areas (Eider catchment in northern Germany and Rhineland‐Palatinate in south‐western Germany) show a distinct genetic structure with endemic haplotypes and private alleles indicating (i) that these areas were refugia for A. astacus in central Europe and (ii) that these populations have not been subject to anthropogenic translocations. Further, we found the highest genetic diversity in the Black Sea basin and particularly high differentiation between populations from the western Balkans and the remaining Black Sea populations. The split between Western Balkan and the remaining European populations is estimated to have occurred approximately 700 k years before present, whereas remaining differentiations occurred within the last 450 k years. Using migration modelling, we detected that the North Sea basin and the Baltic Sea basin were colonised independently via different colonisation paths from the eastern Black Sea basin, while the western Balkans did not contribute to this colonisation.

Our results suggest the existence of at least two refugial areas in south‐eastern Europe. To conserve maximum genetic diversity, conservation priorities for noble crayfish should focus on the south‐eastern European genetic hotspots and on populations in central Europe that hold an autochthonous genetic structure (e.g. Langsee in the Eider catchment area). We further propose that each river catchment should form a separate management unit to reduce anthropogenic genetic homogenisation.
Reconstructing long‐term changes (150 years) in the carbon cycle of a clear‐water lake based on the stable carbon isotope composition (δ13C) of chironomid and cladoceran subfossil remains
Authors: Frossard Victor , Verneaux Valérie , Millet Laurent , Jenny Jean‐Philippe , Arnaud Fabien , Magny Michel , Perga Marie‐Elodie 
Published: December 2013

Summary

Long‐term trends, spanning about 150 years, in δ13C values in the head capsules (HCs) of three chironomid taxa and pelagic cladoceran exoskeletons are reported for a reoligotrophicated, deep, clear‐water lake using a multidepth approach. The trends were taxon specific, and Bayesian change point analyses defined three homogenous temporal sequences of HC δ13C.

From the 1850s to the 1930s, the δ13C values were stable and similar in the littoral and deep zones, suggesting that littoral and deep chironomids relied on similar carbon sources; the HCs and cladoceran δ13C values were approximately −32‰, providing no evidence of organic carbon reworking via microbial mineralisation. From the 1930s to the 1950s, the littoral HC and cladoceran δ13C values decreased by 2‰. This decrease was probably related to an increase in respiration processes in the epilimnion following an increase in trophic state of the lake. The deep HC δ13C values remained stable during this period, suggesting that most of the additional primary production due to eutrophication was transferred to higher trophic levels.

From the 1950s onward, the littoral HC and cladoceran δ13C values remained steady, whereas the deep HC values decreased substantially (−4‰), despite the restoration of oligotrophic conditions in open water. This pattern suggests the existence of organic carbon accumulation and microbial mineralisation at the lake bottom as well as a possible increase in methane‐derived carbon consumption by chironomids.

These processes were attributed to a lower trophic efficiency within the pelagic food web, decreasing the functional efficiency of the lake. Our results suggest that the functioning of the lake was characterised by low heterotrophic activities prior to the 1930s and that since the 1990s, the increase in heterotrophic activities has been supported by autochthonous organic carbon recycling.
Mortality of resprouting chaparral shrubs after a fire and during a record drought: physiological mechanisms and demographic consequences
Authors: Pratt R. Brandon , Jacobsen Anna L. , Ramirez Aaron R. , Helms Anjel M. , Traugh Courtney A. , Tobin Michael F. , Heffner Marcus S. , Davis Stephen D. 
Published: December 2013

AbstractWe examined postfire regeneration of chaparral shrubs during an intense drought. This study focused on the demography and physiology of shrub species that resprout from a basal lignotuber following fire. We found significant levels of resprout mortality when intense drought occurred in the year following fire during the period of shrub recovery. Three of the seven sampled resprouting species had the greatest or near greatest levels of mortality ever recorded when compared to previous studies. Most shrub mortality occurred during the drought after individuals had resprouted (i.e. individuals survived fire, resprouted and then subsequently died). Physiological measurements of species with high mortality suggested that resprout stems were highly embolized and xylem hydraulic conductivities were close to zero during the peak of the drought. In addition, lignotubers of two of the three species experiencing high mortality were depleted of starch. Population densities of most shrub species declined after the drought compared with their prefire levels, with the exception of one drought tolerant obligate seeding species. Resprouting shrub species may deplete their carbohydrate reserves during the resprouting process, making them particularly vulnerable to drought because of the need to transpire water to acquire the CO2 that is used to supply energy to a large respiring root system. Drought appears to interact with fire by altering postfire shrub recovery and altering species abundances and composition of chaparral communities.
Topo‐climatic microrefugia explain the persistence of a rare endemic plant in the Alps during the last 21 millennia
Authors: Patsiou Theofania S. , Conti Elena , Zimmermann Niklaus E. , Theodoridis Spyros , Randin Christophe F. 
Published: December 2013

AbstractOngoing rapid climate change is predicted to cause local extinction of plant species in mountain regions. However, some plant species could have persisted during Quaternary climate oscillations without shifting their range, despite the limited evidence from fossils. Here, we tested two candidate mechanisms of persistence by comparing the macrorefugia and microrefugia (MR) hypotheses. We used the rare and endemic Saxifraga florulenta as a model taxon and combined ensembles of species distribution models (SDMs) with a high‐resolution paleoclimatic and topographic dataset to reconstruct its potential current and past distribution since the last glacial maximum. To test the macrorefugia hypothesis, we verified whether the species could have persisted in or shifted to geographic areas defined by its realized niche. We then identified potential MR based on climatic and topographic properties of the landscape and applied refined scenarios of MR dynamics and functions over time. Last, we quantified the number of known occurrences that could be explained by either the macrorefugia or MR model. A consensus of two or three SDM techniques predicted absence between 14–10, 3–4 and 1 ka bp, which did not support the macrorefugia model. In contrast, we showed that S. florulenta could have contracted into MR during periods of absence predicted by the SDMs and later re‐colonized suitable areas according to the macrorefugia model. Assuming a limited and realistic seed dispersal distance for our species, we explained a large number of the current occurrences (61–96%). Additionally, we showed that MR could have facilitated range expansions or shifts of S. florulenta. Finally, we found that the most recent and the most stable MR were the ones closest to current occurrences. Hence, we propose a novel paradigm to explain plant persistence by highlighting the importance of supporting functions of MR when forecasting the fate of plant species under climate change.
Legal constraints and opportunities for biochar: a case analysis of EU law
Authors: van Laer Tania , de Smedt Peter , Ronsse Frederik , Ruysschaert Greet , Boeckx Pascal , Verstraete Willy , Buysse Jeroen , Lavrysen Luc J. 
Published: December 2013

AbstractThis article addresses biochar from a legal point of view. It analyses different policies and regulations from a European (Flemish) point of view and provides a first and general insight in what potential legal constraints the development of a biochar industry might face and what opportunities lie ahead. This is due to the fact that biochar is a recent product and a lot of scientific uncertainty still exists regarding the consequences of its application. From the analysis it appears a multitude of policies and legislative measures influence the development of the biochar industry. Hence, it is important that all these policies and legislative measures are analyzed in an appropriate manner. Moreover, considerable lobbying, negotiating and cooperation between different disciplines (legal, scientific, economical, etc.) will be required so as to develop a feasible and safe biochar framework.