Neural Networks Are Tuned Near Criticality During a Cognitive Task and Distanced from Criticality In a Psychopharmacological Model of Alzheimer's Disease biorxiv.org/content/10.1101/20

Neural Networks Are Tuned Near Criticality During a Cognitive Task and Distanced from Criticality In a Psychopharmacological Model of Alzheimer's Disease

Dynamical systems that exhibit transitions between ordered and disordered states are described as "critical" when the system is at the borderline between these states. The ability of criticality to explain a variety of brain properties, including optimal information processing, makes it of considerable interest to investigate whether these in vivo networks display critical behaviour, and whether some forms of cognitive impairment such as dementia might display altered critical behaviour. To investigate these questions, the activity of several hundred hippocampal CA1 neurons in freely-behaving mice was studied with miniscope widefield calcium imaging during rest, a novel object recognition task, and novel object recognition after administration of the amnesic drug scopolamine which acts as a psychopharmacological model of Alzheimer's disease. Utilizing rigorous metrics of criticality including the Deviation from Criticality Coefficient and Branching Ratio, the ensemble neural activity in the hippocampus was observed to display evidence of near-critical behaviour during rest periods, but moved significantly closer to a critical state when engaged in a cognitive task. The dynamics were observed to move significantly away from criticality during the cognitive task after scopolamine administration. In contrast to previous theoretical predictions, our results indicate that hippocampus neural networks move closer to criticality under cognitive load, and that critical dynamical regimes produce a near-optimal state for cognitive operations. ### Competing Interest Statement The authors have declared no competing interest.

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Broadening the scope: Multiple functional connectivity networks underlying threat and safety signaling biorxiv.org/content/10.1101/20

Broadening the scope: Multiple functional connectivity networks underlying threat and safety signaling

Introduction: Threat learning and extinction processes are thought to be foundational to anxiety and fear-related disorders. However, the study of these processes in the human brain has largely focused on a priori regions of interest, owing partly to the ease of translating between these regions in human and non-human animals. Moving beyond analyzing focal regions of interest to whole-brain dynamics during threat learning is essential for understanding the neuropathology of fear-related disorders in humans. Methods: 223 participants completed a 2-day Pavlovian threat conditioning paradigm while undergoing fMRI. Participants completed threat acquisition and extinction. Extinction recall was assessed 48 hours later. Using a data-driven group independent component analysis (ICA), we examined large-scale functional connectivity networks during each phase of threat conditioning. Connectivity networks were tested to see how they responded to conditional stimuli during early and late phases of threat acquisition and extinction and during early trials of extinction recall. Results: A network overlapping with the default mode network involving hippocampus, vmPFC, and posterior cingulate was implicated in threat acquisition and extinction. Another network overlapping with the salience network involving dACC, mPFC, and inferior frontal gyrus was implicated in threat acquisition and extinction recall. Other networks overlapping with parts of the salience, somatomotor, visual, and fronto-parietal networks were involved in the acquisition or extinction of learned threat responses. Conclusions: These findings help confirm previous investigations of specific brain regions in a model-free fashion and introduce new findings of spatially independent networks during threat and safety learning. Rather than being a single process in a core network of regions, threat learning involves multiple brain networks operating in parallel coordinating different functions at different timescales. Understanding the nature and interplay of these dynamics will be critical for comprehensive understanding of the multiple processes that may be at play in the neuropathology of anxiety and fear-related disorders. ### Competing Interest Statement The authors have declared no competing interest.

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Metacognition and Problem Solving: How Self-Coaching Helps First-Year Students Move Past the Discomfort of Monitoring biorxiv.org/content/10.1101/20

Metacognition and Problem Solving: How Self-Coaching Helps First-Year Students Move Past the Discomfort of Monitoring

Stronger metacognitive regulation skills are linked to increased academic achievement. Metacognition has primarily been studied using retrospective methods, but these methods limit access to students' in-the-moment metacognition. We investigated first-year life science students' in-the-moment metacognition while they solved challenging problems, and asked 1) What metacognitive regulation skills are evident when first-year life science students solve problems on their own? and 2) What aspects of learning self-efficacy do first-year life science students reveal when they solve problems on their own? Think aloud interviews were conducted with 52 first-year life science students across three institutions and analyzed using qualitative content analysis. Our results reveal that first-year life science students use an array of monitoring and evaluating skills while solving problems, which challenges the deficit-oriented notion that students enter college with poor metacognitive skills. Additionally, a handful of students self-coached or encouraged themselves as they confronted aspects of the problems that were unfamiliar. These verbalizations suggest ways we can encourage students to couple their metacognitive regulation skills and self-efficacy to persist when faced with challenging disciplinary problems. Based on our findings, we offer recommendations for how instructors can help first-year life science students develop and strengthen their metacognition to achieve improved problem-solving performance. ### Competing Interest Statement The authors have declared no competing interest.

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Structural flexibility of apolipoprotein E-derived arginine-rich peptides improves their cell penetration capability biorxiv.org/content/10.1101/20

Structural flexibility of apolipoprotein E-derived arginine-rich peptides improves their cell penetration capability

Amphipathic arginine-rich peptide, A2-17, exhibits moderate perturbation of lipid membranes and the highest cell penetration among its structural isomers. We investigated the direct cell-membrane penetration mechanism of the A2-17 peptide. We designed structurally constrained versions of A2-17, stapled (StpA2-17) and stitched (StchA2-17), whose α-helical conformations were stabilized by chemical crosslinking. Circular dichroism confirmed that StpA2-17 and StchA2-17 had higher α-helix content than A2-17 in aqueous solution. Upon liposome binding, only A2-17 exhibited a coil-to-helix transition. Confocal microscopy revealed that A2-17 had higher cell penetration efficiency than StpA2-17 in HeLa cells. Partitioning into lipid membranes was more prominent for StchA2-17 than for A2-17 or StpA2-17; StchA2-17 remained on the cell membrane without cell penetration. Tryptophan fluorescence analysis suggested that A2-17 and its analogs had similar membrane-insertion positions between the interface and hydrophobic core. Atomic force microscopy demonstrated that A2-17 reduced the mechanical rigidity of liposomes to a greater extent than StpA2-17 and StchA2-17. Finally, electrophysiological analysis showed that A2-17 induced a higher charge influx through transient pores in a planer lipid bilayer than StpA2-17 and StchA2-17. These findings indicate that structural flexibility, which enables diverse conformations of A2-17, leads to a membrane perturbation mode that contributes to cell membrane penetration. ### Competing Interest Statement The authors have declared no competing interest.

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Inferring the Hoxa1 Gene Regulatory Network in Mouse Embryonic Stem Cells: Time-Series RNA-seq Data and Computational Modeling Approach biorxiv.org/content/10.1101/20

Inferring the Hoxa1 Gene Regulatory Network in Mouse Embryonic Stem Cells: Time-Series RNA-seq Data and Computational Modeling Approach

The homeotic gene Hoxa1 plays a pivotal role in regulating embryonic pattern formation and morphogenesis during mouse embryogenesis. However, despite the identification of a number of putative Hoxa1 target genes, the intricate regulatory relationships between these targets remain largely elusive. Leveraging the advancements in high-throughput technologies and sophisticated computational methods, we aimed to infer the Gene Regulatory Networks (GRNs) governed by Hoxa1 that direct cellular function, morphology, and/or differentiation. To achieve this, we generated time-series RNA-seq data from Retinoic Acid (RA)-treated Wild Type versus Hoxa1-null mouse ES cells, enabling the construction of the Hoxa1 GRN. To create this GRN, we employed NARROMI, a published technique known for its noise reduction capabilities and improved accuracy in gene-regulation inference. Using this technique, we identified putative direct and indirect connections between Hoxa1 and a set of genes with known relevance in embryonic development. Validation through qPCR confirmed the Hoxa1-dependence on mRNA expression for selected genes, both within the immediate vicinity (direct) and in secondary interactions (indirect). Furthermore, by mapping the candidate genes to relevant Gene Ontology (GO) networks, we verified their involvement in processes likely regulated by Hoxa1. Our findings provide compelling evidence supporting the accuracy of the NARROMI analysis in generating a hierarchical network of genes under the transcriptional control of Hoxa1 Transcription Factor (TF), specifically in mouse ES cells. This network reveals a pool of promising candidate genes that may function as direct targets of Hoxa1. However, further investigations, including the characterization of Hoxa1 protein interactions with target loci DNA, are necessary to confirm their direct regulatory relationship with this TF. Moreover, the time-series RNA-seq data from Wild Type ES cells, coupled with the methodology employed in this study, hold the potential for constructing GRNs for additional TFs activated by RA. This comprehensive approach can shed further light on the intricate regulatory networks governing cellular function, morphology, and differentiation, advancing our understanding of embryonic development and gene regulation processes. ### Competing Interest Statement The authors have declared no competing interest.

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Distinct Microstructural Heterogeneities Underpin Specific Micromechanical Properties in Human ACL Femoral and Tibial Entheses biorxiv.org/content/10.1101/20

Distinct Microstructural Heterogeneities Underpin Specific Micromechanical Properties in Human ACL Femoral and Tibial Entheses

The anterior cruciate ligament (ACL) is anchored to the femur and tibia by a specialized interface tissue called the enthesis, which transfers forces in multiple directions and magnitudes without accruing fatigue damage during loading cycles over a lifetime. However, the precise structural and mechanical characteristics of the ACL femoral enthesis (FE) and tibial enthesis (TE) and their intricate interplay are unknown. In this study, we identified two ultrathin-graded mineralization regions in the FE (~21 μm) and TE (~14 μm), both of which exhibited distinct biomolecular compositions and mineral assembly patterns. FE interface exhibited progressively maturing hydroxyapatites (HAps), whereas minerals at the TE interface region changed from an amorphous phase (ACP) to HAps with increasing crystallinity. The LC-MS/MS results revealed that MGP protein uniquely enriched at the TE interface may be favorable for stabilizing ACP, while CLEC11A enriched at the FE interface could facilitate osteogenesis of the interface. The finite element analysis results indicated that the FE model was more resistant to shearing, while the TE model facilitated tensile resistance. It suggested that the great discrepancy in biomolecular expression and the corresponding mineral assembling heterogeneities together contributed to the superior mechanical properties of both the FE and TE models. These findings provide new perspectives regarding the management of ACL injury and the development of high-performance interface materials. ### Competing Interest Statement The authors have declared no competing interest.

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A Hybrid Transistor with Transcriptionally Controlled Computation and Plasticity biorxiv.org/content/10.1101/20

A Hybrid Transistor with Transcriptionally Controlled Computation and Plasticity

Organic electrochemical transistors (OECTs) are ideal devices for translating biological signals into electrical readouts and have applications in bioelectronics, biosensing, and neuromorphic computing. Despite their potential, developing programmable and modular methods for living systems to interface with OECTs has proven challenging. Here we describe hybrid OECTs containing the model electroactive bacterium Shewanella oneidensis that enable the transduction of biological computations to electrical responses. Specifically, we fabricated planar p-type OECTs and demonstrated that channel de-doping is driven by extracellular electron transfer (EET) from S. oneidensis. Leveraging this mechanistic understanding and our ability to control EET flux via transcriptional regulation, we used plasmid-based Boolean logic gates to translate biological computation into current changes within the OECT. Finally, we demonstrated EET-driven changes to OECT synaptic plasticity. This work enables fundamental EET studies and OECT-based biosensing and biocomputing systems with genetically controllable and modular design elements. ### Competing Interest Statement The authors have declared no competing interest.

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Trans-Omics analysis of post injury thrombo-inflammation identifies endotypes and trajectories in trauma patients. biorxiv.org/content/10.1101/20

Trans-Omics analysis of post injury thrombo-inflammation identifies endotypes and trajectories in trauma patients.

Understanding and managing the complexity of trauma-induced thrombo-inflammation necessitates an innovative, data-driven approach. This study leveraged a trans-omics analysis of longitudinal samples from trauma patients to illuminate molecular endotypes and trajectories that underpin patient outcomes, transcending traditional demographic and physiological characterizations. We hypothesize that trans-omics profiling reveals underlying clinical differences in severely injured patients that may present with similar clinical characteristics but ultimately have very different responses to treatment and clinical outcomes. Here we used proteomics and metabolomics to profile 759 of longitudinal plasma samples from 118 patients at 11 time points and 97 control subjects. Results were used to define distinct patient states through data reduction techniques. The patient groups were stratified based on their shock severity and injury severity score, revealing a spectrum of responses to trauma and treatment that are fundamentally tied to their unique underlying biology. Ensemble models were then employed, demonstrating the predictive power of these molecular signatures with area under the receiver operating curves of 80 to 94% for key outcomes such as INR, ICU-free days, ventilator-free days, acute lung injury, massive transfusion, and death. The molecularly defined endotypes and trajectories provide an unprecedented lens to understand and potentially guide trauma patient management, opening a path towards precision medicine. This strategy presents a transformative framework that aligns with our understanding that trauma patients, despite similar clinical presentations, might harbor vastly different biological responses and outcomes. ### Competing Interest Statement ADA and KCH are founders of Omix Technologies Inc. ADA is a scientific advisory board member for Hemanext Inc and Macopharma Inc. All the other authors have no conflicts to disclose.

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Mapping Human Tissues with Highly Multiplexed RNA in situ Hybridization biorxiv.org/content/10.1101/20

Mapping Human Tissues with Highly Multiplexed RNA in situ Hybridization

In situ transcriptomic techniques promise a holistic view of tissue organization and cell-cell interactions. Recently there has been a surge of multiplexed RNA in situ techniques but their application to human tissues and clinical biopsies has been limited due to their large size, general lower tissue quality and high background autofluorescence. Here we report DART-FISH, a versatile padlock probe-based technology capable of profiling hundreds to thousands of genes in centimeter-sized human tissue sections at cellular resolution. We introduced an omni-cell type cytoplasmic stain, dubbed RiboSoma that substantially improves the segmentation of cell bodies. We developed a computational decoding-by-deconvolution workflow to extract gene spots even in the presence of optical crowding. Our enzyme-free isothermal decoding procedure allowed us to image 121 genes in a large section from the human neocortex in less than 10 hours, where we successfully recapitulated the cytoarchitecture of 20 neuronal and non-neuronal subclasses. Additionally, we demonstrated the detection of transcripts as short as 461 nucleotides, including neuropeptides and discovered new cortical layer markers. We further performed in situ mapping of 300 genes on a diseased human kidney, profiled >20 healthy and pathological cell states, and identified diseased niches enriched in transcriptionally altered epithelial cells and myofibroblasts. ### Competing Interest Statement KZ and JBF are listed as inventors in a patent related to the method described in this manuscript.

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A neural network model for the evolution of learning in changing environments biorxiv.org/content/10.1101/20

A neural network model for the evolution of learning in changing environments

The ability to learn from past experience is an important adaptation, but how natural selection shapes learning is not well understood. Here, we present a novel way of modelling learning using small neural networks and a simple, biology-inspired learning algorithm. Learning affects only part of the network, and it is governed by the difference between expectations and reality. We used this model to study the evolution of learning under various environmental conditions and different scenarios for the trade-off between exploration (learning) and exploitation (foraging). Efficient learning regularly evolved in our individual-based simulations. However, in line with previous studies, the evolution of learning was less likely in relatively constant environments (where genetic adaptation alone can lead to efficient foraging) or in the case of short-lived organisms (that cannot afford to spend much of their lifetime on exploration). Once learning did evolve, the characteristics of the learning strategy (the duration of the learning period and the learning rate) and the average performance after learning were surprisingly little affected by the frequency and/or magnitude of environmental change. In contrast, an organism's lifespan and the distribution of resources in the environment had a strong effect on the evolved learning strategy. Interestingly, a longer learning period did not always lead to better performance, indicating that the evolved neural networks differ in the effectiveness of learning. Overall, however, we showed that a biologically inspired, yet relatively simple, learning mechanism can evolve to lead to an efficient adaptation in a changing environment. ### Competing Interest Statement The authors have declared no competing interest.

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Influence of functional and phylogenetic dissimilarity on exotic plant invasion depends on spatial scale biorxiv.org/content/10.1101/20

Influence of functional and phylogenetic dissimilarity on exotic plant invasion depends on spatial scale

Darwin theory of natural selection provides two seemingly contradictory hypotheses for explaining the success of introduced species: 1) the preadaptation hypothesis posits that introduced species that are closely related to native species will be more likely to succeed than distantly related invaders because they already possess relevant characteristics; 2) the limiting similarity hypothesis posits that invaders that are more similar to resident species will be less likely to succeed due to competitive exclusion. Previous studies assessing this conundrum show mixed results, possibly stemming from variation in study spatial scales and lack of both functional and phylogenetic information. We used species abundances compiled in a 33-year grassland successional survey based at Cedar Creek Ecosystem Science Reserve (USA) to assess the support for the pre-adaptation and limiting similarity hypotheses at two different spatial scales (neighbourhood scale of 0.5m2, site scale of ~40m2). We combined compositional surveys of 303 vascular plant taxa (256 native, 47 introduced) taken across 2700 plots in a chronosequence of abandonment from agriculture with species functional dissimilarities, phylogenetic distances, environmental covariates and information on species origin. Our results consistently supported the pre-adaptation hypothesis at the site scale but diverged at neighbourhood scale, with functional dissimilarity supporting the limiting similarity hypothesis and phylogenetic distance supporting the preadaptation hypothesis. Introduced species with low leaf dry matter content (LDMC), low height and high seed mass tended to be most abundant than rest of species, while relationships between species abundance and specific leaf area (SLA) varied with scale. Introduced species were more abundant than natives at higher concentrations of soil N but were less abundant than natives over time. Our study highlights the importance of environmental filtering on grassland community assembly at the scale of a site (here 40 m2, a spatial resolution that is usually considered local). This influence of environmental filtering might mask effects of limiting similarity at small-local scales. Our results demonstrate the importance of accounting for both phylogenetic and functional dissimilarity when examining the complex interaction between species biogeographic origin, functional strategies and evolutionary history as considering one alone can lead to different conclusions. ### Competing Interest Statement The authors have declared no competing interest.

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Real-time assessment of the impacts of polystyrene and silver nanoparticles on hatching process and early-stage development of Artemia using a microfluidic platform biorxiv.org/content/10.1101/20

Real-time assessment of the impacts of polystyrene and silver nanoparticles on hatching process and early-stage development of Artemia using a microfluidic platform

The development of real-time in-situ monitoring techniques is key to advancing a mechanistic understanding of the impacts of marine pollution, which is challenging to acquire through traditional end-point toxicity testing. We investigated the impacts of different nanopollutants on the hatching process and early-stage development of marine organisms, a vulnerable life stage, by observing oxygen consumption in real-time and morphological changes at regular intervals using a microfluidic platform. Here, two common and distinct nanoparticle (NP) types - polystyrene (PS) nanoplastic and silver (Ag) nanometal, were examined to assess and compare impacts on the hatching process and nauplius stage (first larval stage) of Artemia , a widely used zooplankton model in ecotoxicological studies. The study was conducted over a wide range of doses that are relevant to different environmental conditions, ranging from 0-1 mg/L, over a period of 24 hours. The hatching process of Artemia is comprised of four distinct stages which can be differentiated by metabolism and morphology: hydration, differentiation, emergence, and hatching. During hatching, NP exposure altered the time needed for the resumption of dormant Artemia cysts (hydration duration) at the lowest dose, dramatically prolonged the differentiation stage, and slowed embryo emergence from the cysts. The remaining time for the hatching stage during the experimental timeframe was also shortened. Overall, the presence of NPs led to increased oxygen consumption in multiple stages of the hatching process. Hatchability increased significantly with NP concentration although mortality showed an inverse pattern. This may be attributed to the increased aggregation of NPs in saltwater with increasing concentration which limits bioavailability during hatching but may be more readily consumed post-hatch. Ag NPs had a greater effect on hatching and mortality in comparison to PS NPs. A significant impact of NPs on swimming speed was observed, with a decrease observed in the presence of PS NPs and an increase observed in the presence of Ag NPs. ### Competing Interest Statement The authors have declared no competing interest.

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Piezo regulates epithelial topology and promotes precision in organ size control biorxiv.org/content/10.1101/20

Piezo regulates epithelial topology and promotes precision in organ size control

Mechanosensitive Piezo channels regulate cell division through calcium-mediated activation of ERK signaling or activate Rho signaling to mediate cell extrusion and cell death. However, systems-level functions of Piezo in regulating organogenesis remain poorly understood. Here, we demonstrate that Piezo controls epithelial cell topology to ensure precise organ growth through the integration of live imaging experiments with pharmacological and genetic perturbations and computational modeling. Notably, knockout or knockdown of Piezo led to bilateral asymmetry in wing phenotypes. While pharmacological activation of Piezo stimulated an increase in the frequency of spikes in cytosolic Ca2+, we discovered that Piezo overexpression counterintuitively reduces Ca2+ signaling dynamics. Knockdown of Piezo inhibited proliferation and decreased apoptosis, resulting in an overall increase in epithelial overcrowding. In contrast, either genetic overexpression or pharmacological activation of Piezo increased cell proliferation and cell removal through basal extrusion. Surprisingly, Piezo overexpression increased the hexagonality of cellular topology. To test whether Piezo regulates cell topology, we formulated computational simulations to investigate how expression levels of Piezo protein regulate cell proliferation and apoptosis through modulation of the cut-off tension required for Piezo channel activation. Quantitative analysis validated computational simulation predictions of how perturbations to Piezo impacted epithelial topology. Overall, our findings demonstrate that Piezo promotes robustness in regulating epithelial topology and is necessary for precise organ size control. ### Competing Interest Statement The authors have declared no competing interest.

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Human intestinal organoid-derived PDGFRα+ mesenchymal stroma empowers LGR4+ epithelial stem cells biorxiv.org/content/10.1101/20

Human intestinal organoid-derived PDGFRα+ mesenchymal stroma empowers LGR4+ epithelial stem cells

The columnar epithelial cells comprising the intestinal tract, stomach, and uterus can be cultured in vitro as organoids or in adherent culture. However, the proliferation of these columnar epithelial cells in adherent culture is limited. Likewise, human pluripotent stem cell (hPSC)-derived intestinal epithelial cells do not show extensive or clonal propagation in vitro. In this study, we induced proliferation of hPSC-derived small intestinal epithelium for a longer time by utilizing mesenchymal stromal cells derived from self-organized intestinal organoids as feeders. The proliferating cells exhibited columnar form, microvilli and glycocalyx formation, and cell polarity, as well as expression of drug-metabolizing enzymes and transporters. It is noteworthy that small intestinal epithelial stem cells cannot be cultured in adherent culture alone, and the stromal cells cannot be replaced by other feeders. Organoid-derived mesenchymal stromal cells resemble the trophocytes essential for maintaining small intestinal epithelial stem cells, and play a crucial role in adherent culture. The high proliferative expansion, productivity, and functionality of hPSC-derived small intestinal epithelial stem cells could have potential applications in pharmacokinetic and toxicity studies and regenerative medicine. ### Competing Interest Statement AU and CJ are co-researchers with Dai Nippon Printing Ltd. AU is a stockholder of iHaes. The other authors declare that there is no conflict of interest regarding the work described herein.

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Use of Chitin:DNA ratio to assess growth form in fungal cells biorxiv.org/content/10.1101/20

Use of Chitin:DNA ratio to assess growth form in fungal cells

Dimorphism, the ability to switch between a 'yeast-like' and a hyphal growth form, is an important feature of certain fungi, including important plant and human pathogens. The switch to hyphal growth is often associated with virulence, pathogenicity, biofilm formation and stress resistance. Thus, the ability to accurately and efficiently measure fungal growth form is key to research into these fungi, especially for discovery of potential drug targets. To date, fungal growth form has been assessed microscopically, a process that is both labour intensive and costly. Here, we unite quantification of the chitin in fungal cell walls and the DNA in nuclei to produce a methodology that allows fungal cell shape to be estimated by calculation of the ratio between cell wall quantity and number of nuclei present in a sample of fungus or infected host tissue. Using the wheat pathogen Zymoseptoria tritici as a test case, with confirmation in the distantly related Fusarium oxysporum, we demonstrate a close, linear relationship between the chitin:DNA ratio and the average polarity index (length/width) of fungal cells. We show the utility of the method for estimating growth form in infected wheat leaves, differentiating between the timing of germination in two different Z. tritici isolates using this ratio. We also show that the method is robust to the occurence of thick-walled chlamydospores, which show a chitin:DNA ratio that is distinct from either 'yeast-like' blastospores or hyphae. ### Competing Interest Statement The authors have declared no competing interest.

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Dendritic cell-mediated responses to secreted Cryptosporidium effectors are required for parasite-specific CD8+ T cell responses biorxiv.org/content/10.1101/20

Dendritic cell-mediated responses to secreted Cryptosporidium effectors are required for parasite-specific CD8+ T cell responses

Cryptosporidium causes debilitating diarrheal disease in patients with primary and acquired defects in T cell function. However, it has been a challenge to understand how this infection generates T cell responses and how they mediate parasite control. Here, Cryptosporidium was engineered to express a parasite effector protein (MEDLE-2) that contains the MHC-I restricted SIINFEKL epitope which is recognized by TCR transgenic OT-I CD8+ T cells. These modified parasites induced expansion of endogenous SIINFEKL-specific and OT-I CD8+ T cells that were a source of IFN-γ that could restrict growth of Cryptosporidium. This T cell response was dependent on the translocation of the effector and similar results were observed with another secreted parasite effector (ROP1). Although infection and these translocated effector proteins are restricted to intestinal epithelial cells (IEC), type I dendritic cells (cDC1) were required to generate CD8+ T cell responses to these model antigens. These data sets highlight Cryptosporidium effectors as targets of the immune system and suggest that crosstalk between enterocytes and cDC1s is crucial for CD8+ T cell responses to Cryptosporidium. ### Competing Interest Statement J.A.G. is currently affiliated with Cell Press, but all experiments performed by her for these studies were done before she worked there. Therefore, the authors declare no competing interests.

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GSK3α/β restrains IFNγ-inducible costimulatory molecule expression in alveolar macrophages, limiting CD4+ T cell activation biorxiv.org/content/10.1101/20

GSK3α/β restrains IFNγ-inducible costimulatory molecule expression in alveolar macrophages, limiting CD4+ T cell activation

Macrophages play a crucial role in eliminating respiratory pathogens. Both pulmonary resident alveolar macrophages (AMs) and recruited macrophages contribute to detecting, responding to, and resolving infections in the lungs. Despite their distinct functions, it remains unclear how these macrophage subsets regulate their responses to infection, including how activation by the cytokine IFNγ is regulated. This shortcoming prevents the development of therapeutics that effectively target distinct lung macrophage populations without exacerbating inflammation. We aimed to better understand the transcriptional regulation of resting and IFNγ-activated cells using a new ex vivo model of AMs from mice, fetal liver-derived alveolar-like macrophages (FLAMs), and immortalized bone marrow-derived macrophages (iBMDMs). Our findings reveal that IFNγ robustly activates both macrophage types; however, the profile of activated IFNγ-stimulated genes varies greatly between these cell types. Notably, FLAMs show limited expression of costimulatory markers essential for T cell activation upon stimulation with only IFNγ. To understand cell type-specific differences, we examined how the inhibition of the regulatory kinases GSK3α/β alters the IFNγ response. GSK3α/β controlled distinct IFNγ responses, and in AM-like cells, we found GSK3α/β restrained the induction of type I IFN and TNF, thus preventing the robust expression of costimulatory molecules and limiting CD4+ T cell activation. Together, these data suggest that the capacity of AMs to respond to IFNγ is restricted in a GSK3α/β-dependent manner and that IFNγ responses differ across distinct macrophage populations. These findings lay the groundwork to identify new therapeutic targets that activate protective pulmonary responses without driving deleterious inflammation. ### Competing Interest Statement The authors have declared no competing interest.

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Temporal association activates projections from the perirhinal cortex and ventral CA1 to the prelimbic cortex and from the prelimbic cortex to the basolateral amygdala biorxiv.org/content/10.1101/20

Temporal association activates projections from the perirhinal cortex and ventral CA1 to the prelimbic cortex and from the prelimbic cortex to the basolateral amygdala

In temporal associations, the prelimbic cortex (PL) has persistent activity during the interval between the conditioned stimulus (CS) and the unconditioned stimulus (US), which maintains a CS representation. Regions cooperating for this function or encoding the CS before the interval could neuroanatomically connect to the PL, supporting learning. The basolateral amygdala (BLA) has CS- and US-responsive neurons, convergently activated. The PL could directly project to the BLA to associate the transient CS memory with the US. We investigated the neural circuit supporting temporal associations using the CFC-5s task, in which a 5-second interval separates the contextual CS from the US. Injecting retrobeads, we quantified c-Fos in PL- or BLA-projecting neurons from 9 regions after CFC-5s or contextual fear conditioning (CFC), in which CS/US overlap. The CFC-5s activated ventral CA1 (vCA1) and perirhinal cortex (PER) neurons projecting to the PL, and PL neurons projecting to BLA. Both CFC-5s and CFC activated vCA1 and lateral entorhinal (LEC) neurons projecting to BLA, and BLA neurons projecting to PL. Both conditioning activated the PER, LEC, cingulate and infralimbic cortices, nucleus reuniens, and ventral subiculum. Results added new relevance to the PER→PL projection and showed that the PL/BLA are reciprocally functionally connected in CFC-5s. ### Competing Interest Statement The authors have declared no competing interest.

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