bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metabolic Energy Sensing by Mammalian CLC Anion/Proton Exchangers
Authors: Grieschat Matthias , Langschwager Katharina , Guzman Raul E. , Fahlke Christoph , Alekov Alexi K. 
Published: February 2019

AbstractMammalian CLC anion/proton exchangers control the pH and [Cl-] of the endolysosomal system, one of the major cellular nutrient uptake pathways. We explored the regulation of the vesicular transporters ClC-3, ClC-4, and ClC-5 by the adenylic system components ATP, ADP, and AMP. Using heterologous expression and whole-cell electrophysiology, we demonstrated that cytosolic ATP and ADP but not AMP and Mg2+-free ADP enhance CLC ion transport via binding to the protein C-terminal CBS domains. Biophysical investigations revealed that the effects depend on the delivery of intracellular protons into the CLC transport machinery and result from modified voltage-dependence and altered probability that CLC proteins undergo silent non-transporting cycles. Our findings demonstrate that the CLC CBS domains are able to serve as energy sensors by detecting changes in the cytosolic ATP/ADP/AMP equilibrium. The adenine nucleotide regulation of vesicular Cl-/H+ exchange creates a link between the activity of the endolysosomal system and the cellular metabolic state.
Autologous micrograft accelerates endogenous wound healing response through ERK-induced cell migration
Authors: Balli Martina , Vitali Francesca , Janiszewski Adrian , Caluwé Ellen , Cortés-Calabuig Alvaro , Duelen Robin , Ronzoni Flavio , Bellazzi Riccardo , Luttun Aernout , Cusella De Angelis Maria G. , Ceccarelli Gabriele , Lluis Frederic , Sampaolesi Maurilio 
Published: February 2019

AbstractDefective fibroblast migration causes delayed wound healing (WH) and chronic skin lesions. Autologous micrograft (AMG) therapies have recently emerged as a new effective treatment able to improve wound healing capacity. However, the molecular mechanisms connecting their beneficial outcomes with the wound healing process are still unrevealed. Here, we show that AMG modulates primary fibroblast migration and accelerates skin re-epithelialization without affecting cell proliferation. We demonstrate that AMG is enriched in a pool of WH-associated growth factors that may provide the initiation signal for a faster endogenous wound healing response. This, in turn leads to increased cell migration rate by elevating activity of extracellular signal-regulated kinase (ERK) pathway and subsequent activation of matrix metalloproteinase expression and their extracellular enzymatic activity. Moreover, AMG-treated wounds showed increased granulation tissue formation and organized collagen content. Overall, we shed light on AMG molecular mechanism supporting its potential to trigger a highly improved wound healing process.
Decreased Activity of theGhrhrandGhPromoters Causes Dominantly Inherited GH Deficiency
Authors: Ariyasu Daisuke , Kubo Emika , Higa Daisuke , Shibata Shinsuke , Takaoka Yutaka , Sugimoto Michihiko , Imaizumi Kazunori , Hasegawa Tomonobu , Araki Kimi 
Published: February 2019

AbstractIsolated growth hormone deficiency type II (IGHD2) is mainly caused by heterozygous splice-site mutations in intron 3 of theGH1gene. A dominant negative effect of the mutant growth hormone (GH) lacking exon 3 on wild-type GH secretion has been proposed; however, the molecular mechanisms involved are elusive. To uncover the molecular systems underlying GH deficiency in IGHD2, we established IGHD2 model mice, which carry both wild-type and mutant copies of the humanGH1gene, replacing each of the endogenous mouseGhloci. Our IGHD2 model mice exhibited growth retardation associated with intact cellular architecture and mildly activated ER stress in the pituitary gland, caused by decreases in the growth hormone releasing hormone receptor (Ghrhr) andGhgene promoter activities. Decreases inGhrhrandGhpromoter activities were likely caused by reduced levels of nuclear CREB3L2, which was demonstrated to stimulate the activity of theGhrhrandGhpromoters. This is the firstin vivostudy revealing a novel molecular mechanism of GH deficiency in IGHD2, representing a new paradigm, differing from widely accepted models.
Dynamic Erasure of Random X-Chromosome Inactivation during iPSC Reprogramming
Authors: Janiszewski Adrian , Talon Irene , Song Juan , Geest Natalie De , To San Kit , Bervoets Greet , Marine Jean-Christophe , Rambow Florian , Pasque Vincent 
Published: February 2019

ABSTRACTBackgroundInduction and reversal of chromatin silencing is critical for successful development, tissue homeostasis and the derivation of induced pluripotent stem cells (iPSCs). X-chromosome inactivation (XCI) and reactivation (XCR) in female cells represent chromosome-wide transitions between active and inactive chromatin states. While XCI has long been studied and provided important insights into gene regulation, the dynamics and mechanisms underlying the reversal of stable chromatin silencing of X-linked genes are much less understood. Here, we use allele-specific transcriptomic approaches to study XCR during mouse iPSC reprogramming in order to elucidate the timing and mechanisms of chromosome-wide reversal of gene silencing.ResultsWe show that XCR is hierarchical, with subsets of genes reactivating early, late and very late. Early genes are activated before the onset of late pluripotency genes activation and the complete silencing of the long non-coding RNA (lncRNA) Xist. These genes are located genomically closer to genes that escape XCI, unlike those reactivating late. Interestingly, early genes also show increased pluripotency transcription factor (TF) binding. We also reveal that histone deacetylases (HDACs) restrict XCR in reprogramming intermediates and that the severe hypoacetylation state of the Xi persists until late reprogramming stages.ConclusionsAltogether, these results reveal the timing of transcriptional activation of mono-allelically repressed genes during iPSC reprogramming, and suggest that allelic activation involves the combined action of chromatin topology, pluripotency transcription factors and chromatin regulators. These findings are important for our understanding of gene silencing, maintenance of cell identity, reprogramming and disease.
Seismic on floating ice: data acquisition versus flexural wave noise
Authors: Johansen Tor Arne , Ruud Bent Ole , Tømmerbakke Ronny , Jensen Kristian 
Published: February 2019

ABSTRACTGeophysical surveying of the Arctic will become increasingly important in future prospecting and monitoring of the terrestrial and adjacent areas in this hemisphere. Seismic data acquired on floating ice are hampered with extensive noise due to ice vibrations related to highly dispersive ice flexural waves generated by the seismic source. Several experiments have been conducted on floating ice in van Mijenfjorden in Svalbard in the Norwegian Arctic to specifically analyse the extent of flexural waves recorded with various seismic receivers and sources deployed both on top of ice and in the water below. The data show that flexural waves are severely damped at 5 m or deeper below the ice and hydrophone data suffer less from these vibrations compared with data recorded on the ice. Aliasing of single receiver hydrophone data can to some extent be suppressed using an in‐line line source of detonating cord. Experiments on ice on shallow water show prominent guided wave modes often referred to as Scholte waves propagating along the seabed. In this case, both flexural and Scholte waves interfere and make a complicated pattern of coherent noise. On shallow water, the positioning and type of the seismic source must be evaluated with respect to the coherent noise generated by these waves. Geophone strings of 25 m effectively suppress both flexural and Scholte waves due to their relative short wavelengths. An airgun generates relative more low‐frequency energy than a surface source of detonating cord. Accordingly, seismic mapping of deep seismic horizons seem to be best achieved using geophone strings of such length and an airgun source. For shallow targets, the use of hydrophones in combination with detonating cord is an appropriate solution. Seismic surveying in the Arctic always have to follow environmental restrictions of not disturbing or harming wildlife and not causing permanent footprints into the vulnerable tundra, which implies that the choice of seismic acquisition strategy might occur as a trade‐off between optimum data quality and environmental constraints.
Spatial synchrony in sub‐arctic geometrid moth outbreaks reflects dispersal in larval and adult life cycle stages
Authors: Vindstad Ole Petter Laksforsmo , Jepsen Jane Uhd , Yoccoz Nigel Gilles , Bjørnstad Ottar N. , Mesquita Michel d. S. , Ims Rolf Anker 
Published: February 2019

Abstract

Spatial synchrony in population dynamics can be caused by dispersal or spatially correlated variation in environmental factors like weather (Moran effect). Distinguishing between these mechanisms is challenging for natural populations, and the study of dispersal‐induced synchrony in particular has been dominated by theoretical modelling and laboratory experiments.

The goal of the present study was to evaluate the evidence for dispersal as a cause of meso‐scale (distances of tens of kilometres) spatial synchrony in natural populations of the two cyclic geometrid moths Epirrita autumnata and Operophtera brumata in sub‐arctic mountain birch forest in northern Norway.

To infer the role of dispersal in geometrid synchrony, we applied three complementary approaches, namely estimating the effect of design‐based dispersal barriers (open sea) on synchrony, comparing the strength of synchrony between E. autumnata (winged adults) and the less dispersive O. brumata (wingless adult females), and relating the directionality (anisotropy) of synchrony to the predominant wind directions during spring, when geometrid larvae engage in windborne dispersal (ballooning).

The estimated effect of dispersal barriers on synchrony was almost three times stronger for the less dispersive O. brumata than E. autumnata. Inter‐site synchrony was also weakest for O. brumata at all spatial lags. Both observations argue for adult dispersal as an important synchronizing mechanism at the spatial scales considered. Further, synchrony in both moth species showed distinct anisotropy and was most spatially extensive parallel to the east–west axis, coinciding closely to the overall dominant wind direction. This argues for a synchronizing effect of windborne larval dispersal. Congruent with most extensive dispersal along the east–west axis, E. autumnata also showed evidence for a travelling wave moving southwards at a speed of 50–80 km/year.

Our results suggest that dispersal processes can leave clear signatures in both the strength and directionality of synchrony in field populations, and highlight wind‐driven dispersal as promising avenue for further research on spatial synchrony in natural insect populations.
Earthworm activity and availability for meadow birds is restricted in intensively managed grasslands
Authors: Onrust Jeroen , Wymenga Eddy , Piersma Theunis , Olff Han 
Published: February 2019

Abstract

Earthworms are an important prey for the endangered meadow birds of northwest Europe. Although intensive grassland management with high manure inputs generally promotes earthworm abundance, it may reduce the effective food availability for meadow birds through desiccation of the topsoil, which causes earthworms to remain deeper in the soil.

We studied the response of Red Worm Lumbricus rubellus, a detritivore, and Grey Worm Aporrectodea caliginosa, a geophage, to soil moisture profiles in the field and under experimental conditions. Surfacing earthworms were counted weekly in eight intensively managed grasslands (treated with high inputs of slurry by slit injection) with variable groundwater tables in the Netherlands. At each count, soil penetration resistance, soil moisture tension and groundwater level were measured, while air temperature and humidity were obtained from a nearby weather station. The response to variation in the vertical distribution of soil moisture was also experimentally studied in the two earthworm species.

In the field, earthworms’ surfacing activity at night was negatively associated with soil moisture tension and positively by relative air humidity. Surprisingly, there was no effect of groundwater level; an important management variable in meadow bird conservation. Under experimental conditions, both L. rubellus and A. caliginosa moved to deeper soil layers (>20 cm) in drier soil moisture treatments, avoiding the upper layer when moisture levels dropped below 30%.

Synthesis and applications. We propose that in intensively managed grasslands with slurry application, topsoil desiccation reduces earthworm availability for meadow birds. This can be counteracted by keeping soil moisture tensions of the top soil above −15 kPa. We suggest that the late raising of groundwater tables in spring and the disturbance of the soil by slit injection of slurry increase topsoil desiccation. This decreases earthworm availability when it matters most for breeding meadow birds. Meadow bird conservation will benefit from revised manure application strategies that promote earthworm activity near or at the soil surface.
Divergent fire management leads to multiple beneficial outcomes for butterfly conservation in a production mosaic
Authors: Gaigher René , Pryke James S. , Samways Michael J. 
Published: February 2019

Abstract

Fire is an intrinsic component of many natural ecosystems. In human‐modified landscapes that occur in fire‐driven ecosystems, it can be difficult to make fire management decisions, as there must be a trade‐off between ideal conservation management and the practicalities of management in an altered landscape.

We assess how biodiversity is influenced by differences in fire regime in a landscape fragmented by timber production. Here, optimal fire management for maintaining grassland integrity is not always possible, due to logistical constraints and fire risk to plantations. We investigate thicket establishment arising from reduced fire frequency, and how this affects butterfly diversity, assemblage structure, indicator species and species associations to larval host plants with different growth forms. Butterflies were sampled along a gradient of woodiness in large‐scale conservation corridors that separate timber compartments.

The two extreme stages along the successional gradient, recently burned grassland and natural forests, supported relatively diverse and complementary butterfly assemblages. Grassland corridors without fire for 2 years were as high in butterfly diversity and similar in composition to recently burned grasslands. However, corridors without fire for >5 years were encroached by thicket and supported lower butterfly diversity. Thicket, with its intermediate vegetation character, was poor habitat for species adapted to either open grassland or to forests. Also, thicket‐encroached areas carry high fire risk to plantations.

Synthesis and applications. In this fragmented, fire‐driven ecosystem, there is more than one burning strategy for achieving positive biodiversity outcomes. We recommend a divergent management approach that covers both extremes of the fire frequency continuum, with the choice depending on the stage of succession and management logistics for each site: (a) frequent burning to prevent woody encroachment in less‐encroached, logistically easier sites or (b) letting succession run its course through thicket to forest by excluding fire in heavily encroached, logistically challenging sites. Both options are practicable and maintain biotopes that have high value for butterfly conservation and low fire risk to plantations. This divergent management approach is a flexible strategy that benefits both conservation and commercial interests across fire‐prone plantation mosaics.
Divergent responses to climate change and disturbance drive recruitment patterns underlying latitudinal shifts of tree species
Authors: Boisvert‐Marsh Laura , Périé Catherine , de Blois Sylvie 
Published: February 2019

Abstract

Climate change is expected to result in a reorganization of the continental distribution of tree species. Recent shifts in distribution patterns have been reported, but it is not always clear how climate change influences these patterns locally, especially in relation to other disturbances.

We investigated latitudinal shifts of four ecologically important tree species between 1970 and 2014 within a study area that encompasses their northernmost range limit in northeastern North America (Quebec, Canada; ~761,000 km2). Changes in latitudinal limits were defined in relation to changes in tree saplings’ occurrence patterns within forest plots resampled over two time periods (1970–1977 and 2003–2014). By examining changes in the frequency of occurrences in different portions of the study area along a latitudinal gradient, we were able to identify spatially explicit patterns of loss or gain (sapling recruitment) resulting in the shifts observed. We then estimated the probability of observing a recruitment event in response to changes in climate, disturbance and their interaction, using a multimodel selection approach.

Latitudinal limits of all four species shifted northward, but these shifts resulted from different patterns of plot occurrence changes, depending on the species and the location examined. Greater recruitment at northern locations than at southern ones drove shifts for Acer saccharum Marsh., Fagus grandifolia Ehrh. and Acer rubrum L., but less so for Betula alleghaniensis Britt. Climate variables indicating changes in early or late growing season conditions were most often selected in models. Warming tended to reduce recruitment probability in the south but increase it in the north, leading to divergent responses for a given species across the study area. Disturbance effects were generally less important than climate change effects, as was their interaction.

Synthesis. Spatially explicit and divergent responses to climate change and disturbance drive recruitment patterns underlying latitudinal shifts of tree species. The importance of early‐ or late‐season climate variables points towards biological processes being affected at critical stages of the life cycle. Understanding the factors that influence species’ migration capacity in a changing climate is crucial to inform adaptive management and conservation practices.
Snail herbivory affects seedling establishment in a temperate forest in the Ozarks
Authors: Liang Anna J. , Stein Claudia , Pearson Eleanor , Myers Jonathan A. , Crandall Raelene M. , Mangan Scott A. 
Published: February 2019

Abstract

Species‐specific herbivores are hypothesized to maintain plant diversity by preventing the dominance of any one plant species. However, a large proportion of herbivores have wide host ranges, and these generalists could have similar effects on plant community composition if they exhibit differences in their host preference. Here, we coupled laboratory and field experiments to test whether a common forest‐understorey snail (Neohelix alleni), a generalist herbivore, has the potential to influence forest composition through differential preference of their plant hosts.

We first performed a cafeteria‐style experiment to test whether N. alleni showed feeding preferences among leaves of five tree species and one shrub common to temperate forests in Missouri, USA. We then conducted a factorial snail and deer exclusion experiment to decouple the effects of snail herbivory from those of white‐tailed deer on seedling establishment of 1‐month‐old newly germinated seedlings of these six woody species in the field. Finally, we examined whether variation in both snail feeding preference and experimentally measured effects of snails on seedling establishment across plant species were related to their relative abundance measured in a 12‐ha forest plot.

In the laboratory, we found that snails preferred leaves of woody species that were less abundant in the forests relative to those species that were more common. In the forest, we found that experimental exclusion of snails had a stronger positive effect on seedling above‐ground biomass and survival over a 1‐year period than did exclusion of deer. Plant species found to be more preferred in the laboratory were also those that had lower seedling establishment in the forest due to the negative effects of snails.

Synthesis. Collectively, our results suggest that greater susceptibility to snail herbivory limits seedling establishment, perhaps contributing to differences in tree species relative abundance. Although less appreciated than their insect and mammal counterparts, herbivory by snails may be significant drivers to the assembly of forest tree communities.
Responses of seedling growth and survival to post‐germination cotyledon removal: An investigation among seven oak species
Authors: Yi Xianfeng , Bartlow Andrew W. , Curtis Rachel , Agosta Salvatore J. , Steele Michael A. 
Published: February 2019

Abstract

Rodents regularly rely on emerged epicotyls to locate and remove cotyledons still containing valuable nutrients. However, the extent to which acorn characteristics influence tolerance to post‐germination predation has received little attention.

Here, we investigated the impact of cotyledon removal following epicotyl emergence on seedling performance and survival of seven oak (Quercus) species. We imitated cotyledon predation at different stages of seedling establishment and development in order to detect effects on seedling height, leaf number and tissue/component mass.

Seedling growth and survival were negatively affected by cotyledon loss regardless of oak species. However, these negative effects decreased as the epicotyl length at which cotyledons were removed increased. We also found that there was a threshold epicotyl length above which seedling survival and performance were relatively unaffected in white oak species compared to red oak species.

Following cotyledon removal, early germinating white oak (section Quercus) seedlings survived and/or grew better than the late germinating red oak (section Lobatae) seedlings. This was likely caused by a difference in dependence on cotyledon reserves, which ultimately affected the ability of seedlings to tolerate cotyledon removal.

Synthesis. From an evolutionary perspective, this is likely to follow from the early germination in white oaks and the ability of seed consumers to locate young seedlings from the emerging epicotyls. Our study has implications for forest regeneration by suggesting additional opportunities for white oak species to establish following epicotyl emergence. Future studies should consider quantifying the rates of post‐germination cotyledon loss.