bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cholinergic control of GnRH neuron physiology and luteinizing hormone secretion: involvement of ACh/GABA co-transmission
Authors: Vastagh Csaba , Farkas Imre , Csillag Veronika , Watanabe Masahiko , Kalló Imre , Liposits Zsolt 
Published: August 2023

AbstractGonadotropin-releasing hormone (GnRH)-synthesizing neurons orchestrate reproduction centrally. Early studies have proposed the contribution of acetylcholine (ACh) to hypothalamic control of reproduction, although the causal mechanisms have not been clarified. Here, we report thatin vivopharmacogenetic activation of the cholinergic system increased the secretion of luteinizing hormone (LH) in orchidectomized mice. 3DISCO immunocytochemistry and electron microscopy revealed the innervation of GnRH neurons by cholinergic axons. Retrograde viral labeling initiated from GnRH-Cre neurons identified the medial septum and the diagonal band of Broca as exclusive sites of origin for cholinergic afferents of GnRH neurons. In acute brain slices, ACh and the ACh receptor (AChR) agonist carbachol evoked a biphasic effect on the firing rate in GnRH neurons, first increasing and then diminishing it. In the presence of tetrodotoxin, carbachol induced an inward current, followed by a decline in the frequency of mPSCs, indicating a direct influence on GnRH cells. RT-PCR and whole-cell patch-clamp studies revealed that GnRH neurons expressed both nicotinic (α4β2, α3β4, and α7) and muscarinic (M1-M5) ACh receptors. The nicotinic AChRs contributed to the nicotine-elicited inward current and the rise in firing rate. Muscarine via M1 and M3 receptors increased, while via M2 and M4 reduced the frequency of both miniature postsynaptic currents (mPSCs) and firing. Optogenetic activation of channelrhodopsin-2-tagged cholinergic axons modified GnRH neuronal activity and evoked co-transmission of ACh and GABA from a subpopulation of boutons. These findings confirm that the central cholinergic system immensely regulates GnRH neurons and activates the HPG-axis via ACh and ACh/GABA neurotransmissions.Significance statementCholinergic drugs influence reproduction centrally, although the exact neuronal targets and regulatory mechanisms remain unsettled. We found that pharmacogenetic activation of the cholinergic system in vivo evoked an augmented LH release. The study also identified cholinergic cell groups in the mouse forebrain that innervate gonadotropin-releasing hormone (GnRH) neurons, the main hypothalamic regulators of reproduction. We also determined the subtypes of nicotinic and muscarinic receptors involved in neuronal information transmission and explored how their ligands affect the electrophysiological activity of GnRH neurons. A subset of cholinergic neurons was found to co-transmit GABA, which excites GnRH cells via GABA-A receptors. The findings suggest a novel, cholinergic regulation of the adult GnRH system in male mice that activates the pituitary-gonadal axis.
Visual routines for detecting causal interactions are tuned to motion direction
Authors: Ohl Sven , Rolfs Martin 
Published: August 2023

AbstractDetecting causal relations structures our perception of events in the world. Here, we determined for visual interactions whether generalized (i.e., feature-invariant) or specialized (i.e., feature-selective) visual routines underlie the perception of causality. To this end, we applied a visual adaptation protocol to assess the adaptability of specific features in classical launching events of simple geometric shapes. We asked observers to report whether they observed a launch or a pass in ambiguous test events (i.e., the overlap between two discs varied from trial to trial). After prolonged exposure to causal launch events (the adaptor) defined by a particular set of features (i.e., a particular motion direction, motion speed, or feature conjunction), observers were less likely to see causal launches in subsequent ambiguous test events than before adaptation. Crucially, adaptation was contingent on the causal impression in launches as demonstrated by a lack of adaptation in non-causal control events. We assessed whether this negative aftereffect transfers to test events with a new set of feature values that were not presented during adaptation. Processing in specialized (as opposed to generalized) visual routines predicts that the transfer of visual adaptation depends on the feature-similarity of the adaptor and the test event. We show that the negative aftereffects do not transfer to unadapted launch directions but do transfer to launch events of different speed. Finally, we used colored discs to assign distinct feature-based identities to the launching and the launched stimulus. We found that the adaptation transferred across colors if the test event had the same motion direction as the adaptor. In summary, visual adaptation allowed us to carve out a visual feature space underlying the perception of causality and revealed specialized visual routines that are tuned to a launch’s motion direction.Significance statementWe used visual adaptation to carve out the visual feature space critical for detecting collisions in visual launching events. Observers were less likely to report perceiving a collision after the repeated viewing of one disc colliding with and launching the movement of another disc. Importantly, observers’ perception of collisions in the direction opposite to the adaptor remained unaffected. However, provided the test stimulus had the adapted direction of motion, the speed or the color of the objects involved in the launching event did not need to be the same as during adaptation for a negative aftereffect to occur. Thus, visual routines that detect causal interactions are selective for motion direction, providing evidence that the perception of causality in a visual interaction relies on low-level perceptual processes.
Inducible genetic ablation ofImmtinduces a lethal disruption of the MICOS complex
Authors: Rockfield Stephanie M. , Turnis Meghan E. , Rodriguez-Enriquez Ricardo , Bathina Madhavi , Ng Seng Kah , Pelletier Stephane , Vogel Peter , Opferman Joseph T. 
Published: August 2023

AbstractThe mitochondrial contact site and cristae organizing system (MICOS) is important for cristae junctions (CJ) formation and for maintaining inner mitochondrial membrane (IMM) architecture. As the largest member, MIC60 is the primary scaffold protein for this complex. While MIC60 has been well studied in yeast and cell culture models, its function in mammals is poorly understood. To address this, we developed a mouse model conditionally deletingImmt(which encodes MIC60) and found that globalImmtdeletion disrupted the MICOS complex and resulted in lethality within 9 days of tamoxifen treatment. Pathologically, these mice display intestinal defects consistent with paralytic ileus, resulting in dehydration. We also identified bone marrow hypocellularity in tamoxifen-treated mice. However, bone marrow transplants fromImmtWTmice failed to rescue survival. Altogether, this novel mouse model demonstrates the importance of MIC60in vivo, in both hematopoietic and non-hematopoietic tissues, and provides a valuable resource for future mechanistic investigations into the MICOS complex. Such investigations could include anin vivostructure-function analysis of MIC60 functional domains, with characterizations that are relevant to human diseases.
Intersectin and Endophilin condensates prime synaptic vesicles for release site replenishment
Authors: Ogunmowo Tyler , Hoffmann Christian , Pepper Renee , Wang Han , Gowrisankaran Sindhuja , Ho Annie , Raychaudhuri Sumana , Cooper Benjamin H. , Milosevic Ira , Milovanovic Dragomir , Watanabe Shigeki 
Published: August 2023

AbstractNeurotransmitter is released from dedicated sites of synaptic vesicle fusion within a synapse. Following fusion, the vacated sites are replenished immediately by new vesicles for subsequent neurotransmission. These replacement vesicles are assumed to be located near release sites and used by chance. Here, we find that replacement vesicles are clustered around this region by Intersectin-1. Specifically, Intersectin-1 forms dynamic molecular condensates with Endophilin A1 near release sites and sequesters vesicles around this region. In the absence of Intersectin-1, vesicles within 20 nm of the plasma membrane are reduced, and consequently, vacated sites cannot be replenished rapidly, leading to depression of synaptic transmission. Similarly, mutations in Intersectin-1 that disrupt Endophilin A1 binding result in similar phenotypes. However, in the absence of Endophilin, this replacement pool of vesicles is available but cannot be accessed, suggesting that Endophilin A1 is needed to mobilize these vesicles. Thus, our work describes a distinct physical region within a synapse where replacement vesicles are harbored for release site replenishment.
Distinct cortical correlates of perception and motor function in balance control
Authors: Mirdamadi Jasmine L. , Ting Lena H. , Borich Michael R. 
Published: August 2023

AbstractFluctuations in brain state alter how we perceive our body and generate movements but have not been investigated in functional whole-body behaviors. During reactive balance control, we recently showed that evoked brain activity is associated with balance ability in healthy young individuals. Further, in individuals with Parkinson’s disease, impairments in whole-body motion perception in reactive balance are associated with clinical balance impairment. Here we investigated brain activity during whole-body motion perception in reactive balance in healthy young adults. We hypothesized that flexibility in brain states underlies successful perception and movement during whole-body movement. We characterized two cortical sensorimotor signals using electroencephalography localized to the supplementary motor area: 1) the “N1 response”, a perturbation-evoked potential that decreases in amplitude with expectancy and is larger in individuals with lower balance function; and 2) pre-perturbation beta oscillatory activity, a rhythm that favors maintenance of the current sensorimotor state and is inversely associated with perception in seated somatosensory perceptual tasks. In a two-alternative forced choice task, participants judged whether pairs of backward support-surface perturbations during standing were in the “same” or “different” direction. As expected, lower whole-body perception was associated with lower balance ability. Within a perturbation pair, N1 attenuation was larger on correctly perceived trials and associated with better balance, but not perception. In contrast, pre-perturbation beta power was higher on incorrectly perceived trials and associated with poorer perception, but not balance. Taken together, flexibility in different cortical processes influences perceptual accuracy but have distinct associations with balance and perceptual ability.
Social network dynamics and gut microbiota composition during alpha male challenges inColobus vellerosus
Authors: Samartino Shelby , Christie Diana , Penna Anna , Sicotte Pascale , Ting Nelson , Wikberg Eva 
Published: August 2023

AbstractThe gut microbiota of group-living animals is strongly influenced by their social interactions, but it is unclear how it responds to social instability. We investigated whether social instability associated with the immigration of new males and challenges to the alpha male position could explain differences in the gut microbiota in adult femaleColobus vellerosusat Boabeng-Fiema, Ghana. During May-August 2007 and May 2008-May 2009, we collected: 1) 53 fecal samples from adult females in 8 social groups for v4 16S rRNA sequencing to determine gut microbiota composition; and 2) demographic and behavioral dataad libitumto determine male immigration, challenges to the alpha male position, and infant births and deaths. We estimated Sørensen and Bray-Curtis beta diversity indices (i.e., between-sample microbiome variation), and they were predicted by year, alpha male stability, group identity, age, and individual identity. We then created 1-m proximity networks using detailed behavioral data via focal follows of 19 adult females in 3 of these groups. Yearly 1-m proximity ties predicted adult female beta-diversity in the two socially stable groups. An alpha male takeover in the third group was associated with infant mortality and temporal variation in proximity networks. Beta-diversity among adult females was predicted by similarity in infant loss status and short-term (rather than yearly) 1-m proximity ties. Although the mechanism driving this association needs to be further investigated in future studies, our findings indicate that alpha male takeovers and social stability are associated with gut microbiota variation and highlight the importance of taking demographic and social network dynamics into account.
Linear Interaction Between Replication and Transcription Shapes DNA Break Dynamics at Recurrent DNA Break Clusters
Authors: Corazzi Lorenzo , Ionasz Vivien , Andrejev Sergej , Wang Li-Chin , Vouzas Athanasios , Giaisi Marco , Di Muzio Giulia , Ding Boyu , Marx Anna J.M. , Henkenjohann Jonas , Allers Michael M. , Gilbert David M. , Wei Pei-Chi 
Published: August 2023

AbstractRecurrent DNA break clusters (RDCs) are replication-transcription collision hotspots; many are unique to neural progenitor cells. Through high-resolution replication sequencing and a capture-ligation assay in mouse neural progenitor cells experiencing replication stress, we unraveled the replication features dictating RDC location and orientation. Most RDCs occur at the replication forks traversing timing transition regions (TTRs), where sparse replication origins connect unidirectional forks. Leftward-moving forks generate telomere-connected DNA double-strand breaks (DSBs), while rightward-moving forks lead to centromere-connected DSBs. Strand-specific mapping for DNA-bound RNA revealed co-transcriptional dual-strand DNA:RNA hybrids present at a higher density in RDC than in other actively transcribed long genes. In addition, mapping RNA polymerase activity revealed that head-to-head interactions between replication and transcription machinery resulted in 60% DSB contribution to the head-on compared to 40% for co-directional. Our findings revealed TTR as a novel fragile class and highlighted how the linear interaction between transcription and replication impacts genome stability.
Exploiting the Affimer platform against influenza A virus
Authors: Debski-Antoniak Oliver , Flynn Alex , Klebl David P. , Tiede Christian , Wilson Ian A. , Muench Stephen P. , Tomlinson Darren , Fontana Juan 
Published: August 2023

AbstractInfluenza A virus (IAV) is well known for its pandemic potential. While current surveillance and vaccination strategies are highly effective, therapeutic approaches are short-lived due to the high mutation rates of IAV. Currently, monoclonal antibodies (mAbs) have emerged as a promising approach to tackle future IAV pandemics. Additionally, several antibody-like alternatives exist that aim to improve upon mAbs. Affimers, one such alternative, benefit from a short development time, high expression levels inE. coli, and complete animal-free production. Here we exploited the Affimer platform to isolate and produce specific and potent inhibitors of IAV. Starting from a monomeric version of the IAV trimeric hemagglutinin (HA) fusion protein, we isolated 12 Affimers that inhibit IAV H3 subtype infectionin vitro. Two of these Affimers were characterised in detail: they exhibited binding affinities to the target H3 HA protein in the nM range and bound specifically to the HA1 head domain. Cryo-EM employing a novel spray approach to prepare cryo-grids allowed us to image HA-Affimer complexes. Combined with functional assays, we determined that the mode of inhibition of these Affimers is based on blocking the interaction of HA to the host-cell receptor - sialic acid. Additionally, these Affimers inhibited IAV strains closely related to the one employed for Affimer isolation. Overall, these results support the use of Affimers as an alternative to existing targeted therapies for IAV and pave the way for their use as diagnostic reagents.ImportanceInfluenza A virus is one of the few viruses that can cause devastating pandemics. Due to the high mutation rates of this virus, annual vaccination is required and antivirals are short-lived. Monoclonal antibodies present a promising approach to tackle influenza virus infections, but are associated with some limitations. To improve on this strategy, we explored the Affimer platform, which are antibody-like, bacterially made proteins. By performing phage-display against a monomeric version of influenza virus fusion protein, an established viral target, we were able to isolate Affimers that inhibit influenza virus infectionin vitro. We characterised the mechanism of inhibition of the Affimers by challenging with related influenza virus strains. We additionally characterised an HA-Affimer complex structure, using a novel approach to prepare samples for cryo-electron microscopy. Overall, these results show that Affimers are a promising tool against influenza virus infection.
Dominant nitrogen metabolisms of a warm, seasonally anoxic freshwater ecosystem revealed using genome resolved metatranscriptomics
Authors: Fadum J. M. , Borton M. A. , Daly R. A. , Wrighton K. C. , Hall E. K. 
Published: August 2023

AbstractReactive nitrogen (N) is one of the principal drivers of primary productivity across aquatic ecosystems. However, the microbial communities and emergent metabolisms which govern N cycling in tropical lakes are both distinct from and poorly understood relative to those found in temperate lakes. This latitudinal difference is largely due to the warm (>20 °C) temperatures of tropical lake anoxic hypolimnions (deepest portion of a stratified water column) which result in unique anaerobic metabolisms operating without the temperature constraints found in lakes at temperate latitudes. As such, tropical hypolimnions provide a platform for exploring microbial membership and functional diversity. To better understand N metabolism in warm anoxic waters, we combined measurements of geochemistry and water column thermophysical structure with genome resolved metatranscriptomic analyses of the water column microbiome in Lake Yojoa, Honduras. We sampled above and below the oxycline in June 2021, when the water column was stratified, and again at the same depths and locations in January 2022, when the water column was mixed. We identified 335 different lineages and significantly different microbiome membership between seasons and, when stratified, between depths. Notably,nrfA(indicative of dissimilatory nitrate reduction to ammonium) was upregulated relative to other N metabolism genes in the June hypolimnion. This work highlights the taxonomic and functional diversity of microbial communities in warm and anoxic inland waters, providing insight into the contemporary microbial ecology of tropical ecosystems as well as inland waters at higher latitudes as water columns continue to warm in the face of global change.ImportanceIn aquatic ecosystems where primary productivity is limited by nitrogen (N), whether continuously, seasonally, or in concert with additional nutrient limitations, increased inorganic N availability can reshape ecosystem structure and function, potentially resulting in eutrophication and even harmful algal blooms (HABs). Whereas microbial metabolic processes such as mineralization and dissimilatory nitrate reduction to ammonium (DNRA) increase inorganic N availability, denitrification removes bioavailable N from the ecosystem. Therefore, understanding these key microbial mechanisms is critical to the sustainable management and environmental stewardship of inland freshwater resources. This study identifies and characterizes these crucial metabolisms in a warm, seasonally anoxic ecosystem. Results are contextualized by an ecological understanding of the study system derived from a multi-year continuous monitoring effort. This unique dataset is the first of its kind in this largely understudied ecosystem (tropical lakes) and also provides insight into microbiome function, and associated taxa, in warm anoxic freshwaters.
Crystallographic and thermodynamic evidence of negative cooperativity of flavin and tryptophan binding in the flavin-dependent halogenases AbeH and BorH
Authors: Ashaduzzaman Md , Lingkon Kazi , De Silva Aravinda J. , Bellizzi John J. 
Published: August 2023

AbstractThe flavin-dependent halogenase AbeH produces 5-chlorotryptophan in the biosynthetic pathway of the chlorinated bisindole alkaloid BE-54017. We report thatin vitro, AbeH (assisted by the flavin reductase AbeF) can chlorinate and brominate tryptophan as well as other indole derivatives and substrates with phenyl and quinoline groups. We solved the X-ray crystal structures of AbeH alone and complexed with FAD, as well as crystal structures of the tryptophan-6-halogenase BorH alone, in complex with 6-chlorotryptophan, and in complex with FAD and tryptophan. Partitioning of FAD and tryptophan into different chains of BorH and failure to incorporate tryptophan into AbeH/FAD crystals suggested that flavin and tryptophan binding are negatively coupled in both proteins. ITC and fluorescence quenching experiments confirmed the ability of both AbeH and BorH to form binary complexes with FAD or tryptophan and the inability of tryptophan to bind to AbeH/FAD or BorH/FAD complexes. FAD could not bind to BorH/tryptophan complexes, but FAD appears to displace tryptophan from AbeH/tryptophan complexes in an endothermic entropically-driven process.
IC3 Protocol – A novel digital health method for monitoring cognition after stroke
Authors: Gruia Dragos C. , Trender William , Hellyer Peter , Banerjee Soma , Kwan Joseph , Zetterberg Henrik , Hampshire Adam , Geranmayeh Fatemeh 
Published: August 2023

AbstractIntroductionStroke is a major cause of death and disability worldwide, frequently resulting in persistent cognitive deficits among survivors. These deficits negatively impact recovery and therapy engagement, and their treatment is consistently rated as high priority by stakeholders and clinicians. Although clinical guidelines endorse cognitive screening for post-stroke management, there is currently no gold standard approach for identifying cognitive deficits after stroke, and clinical stroke services lack the capacity for long-term cognitive monitoring and care. Currently available assessment tools are either not stroke-specific, not in-depth or lack scalability, leading to heterogeneity in patient assessments.Methods and AnalysisTo address these challenges, a cost-effective, scalable, and comprehensive screening tool is needed to provide a stroke-specific assessment of cognition. The current study presents such a novel digital tool, the Imperial Comprehensive Cognitive Assessment in Cerebrovascular Disease (IC3), designed to detect both domain-general and domain-specific cognitive deficits in patients after stroke with minimal input from a health professional. To ensure its reliability, we will utilise multiple validation approaches, and aim to recruit a large normative sample of age-, gender-, and education-matched UK-based controls. Moreover, the IC3 assessment will be integrated within a larger prospective observational longitudinal clinical trial, where post-stroke cognition will be examined in tandem with brain imaging and blood biomarkers to identify novel multimodal biomarkers of recovery after stroke. This study will enable deeper cognitive phenotyping of patients at a large scale, whilst identifying those with highest risk of progressive cognitive decline, as well as those with greatest potential for recovery.Ethics and disseminationThis study has been approval by South West - Frenchay Research Ethics Committee (IRAS 299333), and authorized by the UK’s Health Research Authority. Study registration. The study is registered as an observational trial underNCT05885295.