bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rapid appetitive transitions are sculpted by amygdala to accumbens pathways
Authors: Millan E. Zayra , Lim Jun Hua , Power John M. , McNally Gavan P. 
Published: April 2021

AbstractForaging, pursuit, and predation rapidly transition into behavioral quiescence during reward capture and consumption. While appetitive-consummatory dissociations are embedded at both psychological and neural levels, the mechanisms controlling switches or transitions between appetitive seeking and consummatory behaviors remain poorly understood. Here we identify the BLA→AcbSh pathway as critical to these transitions by showing that this pathway inhibits the appetitive seeking response in the presence of consummatory demands. Using an appetitive cue-discrimination task in male rats, we show that reward delivery is a significant driver of seeking inhibition and that a BLA→AcbSh pathway mediates this inhibition. This role in suppressing seeking responses during periods of consumption was not due to a general suppression of behavior because responding to other cues during the same test was unaffected. Moreover, it was specific to the BLA→AcbSh pathway, because the contribution of the BLA→AcbC pathway to appetitive switching was distinct and modest. State-dependent silencing of BLA→AcbSh revealed that the modulation of seeking before and after reward delivery are co-dependent. Finally, we found that BLA terminals in AcbSh have functional connectivity to LH-projecting AcbSh neurons, thereby identifying a BLA→AcbSh→LH pathway as a putative route for the rapid regulation of appetitive behaviors. Taken together, these findings suggest that the BLA→AcbSh pathway is a core component of an appetitive switching system, recruited under conditions requiring rapid or dynamic shifts in appetitive behavior, and that this pathway enables these shifts by actively inhibiting seeking.Significance statementForaging, pursuit, and predation quickly transition into behavioral quiescence during reward capture and consumption. These transitions are critical for flexible and responsive sequences of behavior. Here we show that behavioral transitions are actively controlled at the limbic-striatal interface. We identify reward receipt as a proximal trigger for transition between reward seeking and taking, we identify active inhibition as the functional operation of this transition, and we identify the basolateral amygdala→accumbens shell pathway as critical to this functional operation.
The H4K20 demethylase DPY-21 regulates the dynamics of condensin DC binding
Authors: Breimann Laura , Morao Ana Karina , Kim Jun , Jimenez David Sebastian , Maryn Nina , Bikkasani Krishna , Carrozza Michael J , Albritton Sarah E , Kramer Maxwell , Street Lena Annika , Cerimi Kustrim , Schumann Vic-Fabienne , Bahry Ella , Preibisch Stephan , Woehler Andrew , Ercan Sevinç 
Published: April 2021

ABSTRACTCondensin is a multi-subunit SMC complex that binds to and compacts chromosomes. Here we addressed the regulation of condensin binding dynamics usingC. eleganscondensin DC, which represses X chromosomes in hermaphrodites fordosagecompensation. We established fluorescence recovery after photobleaching (FRAP) using the SMC4 homolog DPY-27 and showed that a well-characterized ATPase mutation abolishes its binding. Next, we performed FRAP in the background of several chromatin modifier mutants that cause varying degrees of X-chromosome derepression. The greatest effect was in a null mutant of the H4K20me2 demethylase DPY-21, where the mobile fraction of condensin DC reduced from ∼30% to 10%. In contrast, a catalytic mutant ofdpy-21did not regulate condensin DC mobility. Hi-C data in thedpy-21null mutant showed little change compared to wild type, uncoupling Hi-C measured long-range DNA contacts from transcriptional repression of the X chromosomes. Together, our results indicate that DPY-21 has a non-catalytic role in regulating the dynamics of condensin DC binding, which is important for transcription repression.
The neural correlates of semantic and grammatical encoding during sentence production in a second language: evidence from an fMRI study using syntactic priming
Authors: Nakagawa Eri , Koike Takahiko , Sumiya Motofumi , Shimada Koji , Makita Kai , Yoshida Haruyo , Yokokawa Hirokazu , Sadato Norihiro 
Published: April 2021

AbstractJapanese English learners have difficulty speaking Double Object (DO; give B A) than Prepositional Object (PO; give A to B) structures which neural underpinning is unknown. In speaking, syntactic and phonological processing follow semantic encoding, conversion of non-verbal mental representation into a structure suitable for expression. To test whether DO difficulty lies in linguistic or prelinguistic process, we conducted functional magnetic resonance imaging. Thirty participants described cartoons using DO or PO, or simply named them. Greater reaction times and error rates indicated DO difficulty. DO compared with PO showed parieto-frontal activation including left inferior frontal gyrus, reflecting linguistic process. Psychological priming in PO produced immediately after DO and vice versa compared to after control, indicated shared process between PO and DO. Cross-structural neural repetition suppression was observed in occipito-parietal regions, overlapping the linguistic system in pre-SMA. Thus DO and PO share prelinguistic process, whereas linguistic process imposes overload in DO.
The TIR-NBS-LRR protein CSA1 is required for autoimmune cell death in Arabidopsis pattern recognition co-receptorbak1andbir3mutants
Authors: Schulze Sarina , Yu Liping , Ehinger Alexandra , Kolb Dagmar , Saile Svenja C. , Stahl Mark , Franz-Wachtel Mirita , Li Lei , Kasmi Farid El , Cevik Volkan , Kemmerling Birgit 
Published: April 2021

AbstractThe BRI1-associated kinase BAK1/SERK3 is a positive regulator of multiple leucine rich receptor kinase-mediated signaling pathways including pattern triggered immunity (PTI). Absence or overexpression of BAK1 leads to spontaneous cell death formation. BAK1-interacting receptors (BIR) constitutively interact with BAK1, and plants lacking or overexpressing BIR proteins phenocopy the cell death symptoms observed inbak1knock outs or overexpressors. In the interactome of BIR3, the TIR-NBS-LRR protein CONSTITUTIVE SHADE-AVOIDANCE 1 (CSA1) was identified by mass spectrometry. CSA1 physically interacts with BIR proteins and can be detected in complexes with BAK1. Direct interaction was shown only for CSA1 with BIR proteins but not BAK1. Double mutantbak1 bir3genotypes develop strong dwarfism and cell death symptoms that are dependent on EDS1 and salicylic acid. Loss of CSA1 blocksbak1andbak1 bir3-mediated cell death formation thus demonstrating that CSA1 is causal for this type of cell death. We propose that CSA1 guards BIR proteins and initiates autoimmune cell death that is observed when BAK1 BIR complexes are impaired. Our findings reveal how cell death in the absence of BAK1 and BIR3 is executed and links BAK1, a common co-receptor of many pattern recognition receptors, to NLR proteins typically implicated in effector-triggered immunity.
A muscle-related contractile tissue specified by myocardin-related transcription factor activity in Porifera
Authors: Colgren J. , Nichols S.A. 
Published: April 2021

AbstractMuscle-based movement is a hallmark of animal biology, but the evolutionary origins of myocytes – the cells that comprise muscle tissues – are unknown. Sponges (Porifera) provide an opportunity to reconstruct the earliest periods of myocyte evolution. Although sponges are believed to lack muscle, they are capable of coordinated whole-body contractions that purge debris from internal water canals. This behavior has been observed for decades, but their contractile tissues remain uncharacterized; it is an open question whether they have affinity to muscle or non-muscle contractile tissues in other animals. Here, we characterize the endothelial-like lining of water canals (the endopinacoderm) as a primary contractile tissue in the spongeEphydatia muelleri. We find tissue-wide organization of contractile actin-bundles that contain striated-muscle myosin II and transgelin, and that contractions are regulated by the release of internal Ca2+stores upstream of the myosin-light-chain-kinase (MLCK) pathway. Further, we show that the endopinacoderm is developmentally specified by myocardin-related transcription factor (MRTF) as part of an environmentally-inducible transcriptional complex that otherwise is known to function in muscle development, plasticity, and regeneration in other animals. We conclude that both muscle tissues and the endopinacoderm evolved from a common, multifunctional contractile tissue in the animal stem-lineage. Furthermore, as an actin-regulated force-sensor, MRTF-activity offers a mechanism for how water canals dynamically remodel in response to flow and can re-form normally from stem-cells in the absence of the intrinsic positional cues characteristic of embryogenesis in other animals.
Reduction of bundle sheath size boosts cyclic electron flow in C4Setaria viridisacclimated to low light
Authors: Bellasio Chandra , Ermakova Maria 
Published: April 2021

AbstractWhen C4leaves are exposed to low light, CO2concentration in the bundle sheath (BS) cells decreases, causing an increase in photorespiration relative to assimilation, and a consequent reduction in biochemical efficiency. These effects can be mitigated by complex acclimation syndromes, which are of primary importance for crop productivity, but not well studied. We unveil an acclimation strategy involving regulation of electron transport processes. Firstly, we characterise anatomy, gas-exchange and electron transport of C4Setaria viridisgrown under low light. Through a purposely developed biochemical model, we resolve the photon fluxes and reaction rates to explain how the concerted acclimation strategies sustain photosynthetic efficiency. Our results show that a smaller BS in low light-grown plants limited leakiness (the ratio of CO2leak rate out of the BS over the rate of supply via C4acid decarboxylation) but sacrificed light harvesting and ATP production. To counter ATP shortage and maintain high assimilation rates, plants facilitated light penetration through the mesophyll and upregulated cyclic electron flow in the BS. This shade tolerance mechanism based on optimisation of light reactions is potentially more efficient than the known mechanisms involving the rearrangement of carbon metabolism, and can potentially lead to innovative strategies for crop improvement.SignificanceWe mechanistically link the optical cross-section of leaf compartments with the rate of electron transport, the engagement of cyclic electron flow, the relative rate of ATP and NADPH generation, and fluxes through the carbon metabolism. The striking capacity ofSetaria viridisto counter the decrease in light absorption in the bundle sheath with an increase of cyclic electron flow presents perhaps the most efficient mechanism of shade acclimation.
Respiratory dysfunctions in two rodent models of chronic epilepsy and acute seizures and their link with brainstem serotonin system
Authors: Kouchi Hayet , Ogier Michaël , Dieuset Gabriel , Morales Anne , Georges Béatrice , Rouanet Jean-Louis , Martin Benoît , Ryvlin Philippe , Rheims Sylvain , Bezin Laurent 
Published: April 2021

AbstractPatients with drug-resistant epilepsy can experience respiratory alterations notably during seizures. The mechanisms underlying this long-term alteration of respiratory function remain unclear. This study aimed at determining in rats whether epilepsy is associated with alterations of both the respiratory function and brainstem serotonin (5-HT) system. Epilepsy was triggered by pilocarpine-inducedstatus epilepticusin rats. 30-50% of epileptic (EPI) rats exhibited sharp decrease of oxygen consumption (SDOC), low metabolic rate of oxygen and slow regular ventilation; these rats were called EPI/SDOC+ rats. These alterations were only detected in rats with chronic epilepsy, independent of behavioral seizures, persisted over the time, and were not associated with death. In these rats, 5-HT fiber density in the nucleustractus solitariuswas below that of control and EPI/SDOC-rats. Both EPI/SDOC+ rats and DBA/2 mice presenting with fatal respiratory arrest following an audiogenic-induced seizure, a model of sudden and expected death in epilepsy, had increased transcript levels of tryptophan hydroxylase 2 (p<0.001 for both strains) and 5-HT presynaptic transporter (rats: p=0.003; mice: p=0.001). Thus, our data support that 5-HT alterations are associated with chronic and acute epilepsy-related respiratory dysfunctions.
Hsp40s display class-specific binding profiles, serving complementary roles in the prevention of tau amyloid formation
Authors: Irwin Rose , Faust Ofrah , Petrovic Ivana , Wolf Sharon Grayer , Hofmann Hagen , Rosenzweig Rina 
Published: April 2021

ABSTRACTThe microtubule-associated protein, tau, is the major subunit of neurofibrillary tangles, forming insoluble, amyloid-type aggregates associated with neurodegenerative conditions, such as Alzheimer’s disease. Tau aggregation, however, can be prevented in the cell by a class of proteins known as molecular chaperones, which play important roles in maintaining protein homeostasis. While numerous chaperones are known to interact with tau, though, little is known about the detailed mechanisms by which these prevent tau aggregation. Here, we describe the effects of the ATP-independent Hsp40 chaperones, DNAJA2 and DNAJB1, on tau amyloid fiber formation and compare these to the well-studied small heat shock protein HSPB1. We find that each chaperone prevents tau aggregation differently, by interacting with distinct sets of tau species along the aggregation pathway and thereby affecting their incorporation into fibers. Whereas HSPB1 only binds tau monomers, DNAJB1 and DNAJA2 recognize aggregation-prone tau conformers and even mature fibers, thus efficiently preventing formation of tau amyloids. In addition, we find that both Hsp40s bind tau seeds and fibers via their C-terminal domain II (CTDII), with DNAJA2 being further capable of recognizing tau monomers by a second, different site in CTDI. These results provide important insight into the molecular mechanism by which the different members of the Hsp40 chaperone family counteract the formation, propagation, and toxicity of tau aggregates. Furthermore, our findings highlight the fact that chaperones from different families and different classes play distinct, but complementary roles in preventing pathological protein aggregation.
Predictors of genomic differentiation within a hybrid taxon
Authors: Cuevas Angelica , Eroukhmanoff Fabrice , Ravinet Mark , Særtre Glenn-Peter , Runemark Anna 
Published: April 2021

ABSTRACTHybridization is increasingly recognized as an important evolutionary force. Novel genetic methods now enable us to address how the genomes of parental species are combined to build hybrid genomes. However, we still do not know the relative importance of contingencies, genome architecture and local selection in shaping hybrid genomes. Here, we take advantage of the genetically divergent island populations of Italian sparrow on Crete, Corsica and Sicily to investigate the predictors of genomic variation within a hybrid taxon. We test if differentiation is affected by recombination rate, selection, or variation in ancestry proportion from each parent species. We find that the relationship between recombination rate and differentiation is less pronounced within hybrid lineages than between the parent species, as expected if purging of minor parent ancestry in low recombination regions reduces the variation available for differentiation. In addition, we find that differentiation between islands is correlated with differences in selection in two out of three comparisons. Patterns of within-island selection are correlated across all islands, suggesting that shared selection may mould genomic differentiation. The best predictor of strong differentiation within islands is the degree of differentiation from house sparrow, and hence loci with Spanish sparrow ancestry may vary more freely. Jointly, this suggests that constraints and selection interact in shaping the genomic landscape of differentiation in this hybrid species.
Including random effects in statistical models in ecology: fewer than five levels?
Authors: Gomes Dylan G.E. 
Published: April 2021

AbstractAs generalized linear mixed-effects models (GLMMs) have become a widespread tool in ecology, the need to guide the use of such tools is increasingly important. One common guideline is that one needs at least five levels of a random effect. Having such few levels makes the estimation of the variance of random effects terms (such as ecological sites, individuals, or populations) difficult, but it need not muddy one’s ability to estimate fixed effects terms – which are often of primary interest in ecology. Here, I simulate ecological datasets and fit simple models and show that having too few random effects terms does not influence the parameter estimates or uncertainty around those estimates for fixed effects terms. Thus, it should be acceptable to use fewer levels of random effects if one is not interested in making inference about the random effects terms (i.e. they are ‘nuisance’ parameters used to group non-independent data). I also use simulations to assess the potential for pseudoreplication in (generalized) linear models (LMs), when random effects are explicitly ignored and find that LMs do not show increased type-I errors compared to their mixed-effects model counterparts. Instead, LM uncertainty (and p values) appears to be more conservative in an analysis with a real ecological dataset presented here. These results challenge the view that it is never appropriate to model random effects terms with fewer than five levels – specifically when inference is not being made for the random effects, but suggest that in simple cases LMs might be robust to ignored random effects terms. Given the widespread accessibility of GLMMs in ecology and evolution, future simulation studies and further assessments of these statistical methods are necessary to understand the consequences of both violating and blindly following simple guidelines.
An engineered transcriptional reporter of protein localization identifies regulators of mitochondrial and ER membrane protein trafficking in high-throughput screens
Authors: Coukos Robert , Yao David , Sanchez Mateo I. , Strand Eric T. , Weissman Jonathan S. , Bassik Michael C. , Ting Alice Y. 
Published: April 2021

AbstractThe trafficking of specific protein cohorts to the correct subcellular location at the correct time is essential for every signaling and regulatory process in biology. Gene perturbation screens could provide a powerful approach to probe the molecular mechanisms of protein trafficking, but only if protein localization or mislocalization can be tied to a simple and robust phenotype for cell selection, such as cell proliferation or FACS. To broadly empower the study of protein trafficking processes with gene perturbation, we developed a genetically-encoded molecular tool named HiLITR. HiLITR converts protein colocalization into proteolytic release of a membrane-anchored transcription factor, which drives the expression of a chosen reporter gene. Using HiLITR in combination with FACS-based CRISPRi screening in human cell lines, we identify genes that influence the trafficking of mitochondrial and ER tail-anchored proteins. We show that loss of the SUMO E1 component SAE1 results in the mislocalization and destabilization of mitochondrial tail-anchored proteins. We also demonstrate a distinct regulatory role for EMC10 in the ER membrane complex, opposing the transmembrane-domain insertion activity of the complex. Through transcriptional integration of complex cellular functions, HiLITR expands the scope of biological processes that can be studied by genetic perturbation screening technologies.
Recurring adaptive introgression of a supergene variant that determines social organization
Authors: Stolle Eckart , Pracana Rodrigo , López-Osorio Federico , Priebe Marian K. , Hernández Gabriel Luis , Castillo-Carrillo Claudia , Arias Maria Cristina , Paris Carolina Ivon , Bollazzi Martin , Priyam Anurag , Wurm Yannick 
Published: April 2021

AbstractIntrogression has been proposed as an essential source of adaptive genetic variation. However, a key barrier to adaptive introgression is that recombination can break down combinations of alleles that underpin many traits. This barrier might be overcome in supergene regions, where suppressed recombination leads to joint inheritance across many loci. Here, we study the evolution of a large supergene region that determines a major social and ecological trait inSolenopsisfire ants: whether colonies have one queen or multiple queens. Using coalescent-based phylogenies built from the genomes of 365 haploid fire ant males, we show that the supergene variant responsible for multiple-queen colonies evolved in one species and repeatedly spread to other species through introgressive hybridization. This finding highlights how supergene architecture can enable a complex adaptive phenotype to recurrently permeate species boundaries.
Energy expenditure does not explain step length-width choices during walking
Authors: Antos Stephen A. , Kording Konrad P. , Gordon Keith E. 
Published: April 2021

AbstractHealthy young adults have a most preferred walking speed, step length, and step width that are close to energetically optimal. However, people can choose to walk with a multitude of different step lengths and widths, which can vary in both energy expenditure and preference. Here we further investigate step length-width preferences and their relationship to energy expenditure. In line with a growing body of research, we hypothesized that people’s preferred stepping patterns would not be fully explained by metabolic energy expenditure. To test this hypothesis we used a two-alternative forced-choice paradigm. Fifteen participants walked on an oversized treadmill. Each trial participants experienced two stepping patterns and then chose the pattern they preferred. Over time, we adapted the choices such that there was 50% chance of choosing one pattern over another (equally preferred). If people’s preferences are based solely on metabolic energy expenditure, then these equally preferred stepping patterns should have equal energy expenditure. We found that energy expenditure differed across equally preferred step length-width patterns (p < 0.001). On average, longer steps with higher energy expenditures were preferred over shorter and wider steps with lower energy expenditures (p < 0.001). We also asked participants to rank a set of shorter, wider, and longer steps from most preferred to least preferred, and from most energy expended to least energy expended. Only 7/15 participants had the same rankings for their preferences and perceived energy expenditure. Our results suggest that energy expenditure is not the only factor influencing a person’s conscious gait choices.