bluuebunny/crossref_metadata_2025 huggingface dataset:
Development and validation of an enzyme immunoassay for detection and quantification of SARS-CoV-2 salivary IgA and IgG
Authors: Costantini Veronica P. , Nguyen Kenny , Lyski Zoe , Novosad Shannon , Bardossy Ana C. , Lyons Amanda K. , Gable Paige , Kutty Preeta K. , Lutgring Joseph D. , Brunton Amanda , Thornburg Natalie , Brown Allison C. , McDonald L. Clifford , Messer William , Vinjé Jan
Published: September 2021

Oral fluids offer a non-invasive sampling method for the detection of antibodies. Quantification of IgA and IgG antibodies in saliva allows studies of the mucosal and systemic immune response after natural infection or vaccination. We developed and validated an enzyme immunoassay (EIA) to detect and quantify salivary IgA and IgG antibodies against the prefusion-stabilized form of the SARS-CoV-2 spike protein. Normalization against total antibody isotype was performed to account for specimen differences, such as collection time and sample volume. Saliva samples collected from 187 SARS-CoV-2 confirmed cases enrolled in 2 cohorts and 373 pre-pandemic saliva samples were tested. The sensitivity of both EIAs was high (IgA: 95.5%; IgG: 89.7%) without compromising specificity (IgA: 99%; IgG: 97%). No cross reactivity with seasonal coronaviruses was observed. The limit of detection for SARS-CoV-2 salivary IgA and IgG assays were 1.98 ng/mL and 0.30 ng/mL, respectively. Salivary IgA and IgG antibodies were detected earlier in patients with mild COVID-19 symptoms than in severe cases. However, severe cases showed higher salivary antibody titers than those with a mild infection. Salivary IgA titers quickly decreased after 6 weeks in mild cases but remained detectable until at least week 10 in severe cases. Salivary IgG titers remained high for all patients, regardless of disease severity. In conclusion, EIAs for both IgA and IgG had high specificity and sensitivity for the confirmation of current or recent SARS-CoV-2 infections and evaluation of the IgA and IgG immune response.
Suicide and self-harm in low- and middle- income countries during the COVID-19 pandemic: A systematic review
Authors: Knipe Duleeka , John Ann , Padmanathan Prianka , Eyles Emily , Dekel Dana , Higgins Julian PT , Bantjes Jason , Dandona Rakhi , Macleod-Hall Catherine , McGuinness Luke A , Schmidt Lena , Webb Roger T , Gunnell David
Published: September 2021

There is widespread concern over the potential impact of the COVID-19 pandemic on suicide and self-harm globally, particularly in low- and middle-income countries (LMIC) where the burden of these behaviours is greatest. We synthesised the evidence from the published literature on the impact of the pandemic on suicide and self-harm in LMIC.

This review is nested within a living systematic review that continuously identifies published evidence (all languages) through a comprehensive automated search of multiple databases (PubMed; Scopus; medRxiv, PsyArXiv; SocArXiv; bioRxiv; the WHO COVID-19 database; and the COVID-19 Open Research Dataset by Semantic Scholar (up to 11/2020), including data from Microsoft Academic, Elsevier, arXiv and PubMed Central.) All articles identified by the 4th August 2021 were screened. Papers reporting on data from a LMIC and presenting evidence on the impact of the pandemic on suicide or self-harm were included.

A total of 22 studies from LMIC were identified representing data from 12 countries. There was an absence of data from Africa. The reviewed studies mostly report on the early months of COVID-19 and were generally methodologically poor. Few studies directly assessed the impact of the pandemic. The most robust evidence, from time-series studies, indicate either a reduction or no change in suicide and self-harm behaviour.

As LMIC continue to experience repeated waves of the virus and increased associated mortality, against a backdrop of vaccine inaccessibility and limited welfare support, continued efforts are needed to track the indirect impact of the pandemic on suicide and self-harm in these countries.
SARS-CoV-2 circulation in the school setting: A systematic review and meta-analysis
Authors: Martinoli Chiara , La Vecchia Carlo , Raimondi Sara , Bellerba Federica , Sasso Clementina , Basso Alessandra , Cammarata Giulio , Gandini Sara
Published: September 2021

Background

The contribution of children to viral spread in schools is still under debate.

We conducted a systematic review and meta-analysis of studies to investigate SARS-CoV-2 transmission in the school setting.

Methods

Literature searches from April, 2021 and repeated on May, 15th 2021 yielded a total of 1088 publications: screening, contact tracing and seroprevalence studies.

MOOSE guidelines were followed and data analyzed using random-effects models.

Results

From screening studies involving more than 120,000 subjects, we estimated 0.31% (95% Confidence Interval [CI] 0.05-0.81%) SARS-CoV-2 point prevalence in schools. Contact tracing studies, involving a total of 112,622 contacts of children and adults, showed that onward viral transmission was limited (2.54%; 95%CI 0.76-5.31). Young index cases were found to be 74% significantly less likely than adults to favor viral spread (Odds Ratio [OR]=0.26; 95%CI 0.11-0.63) and were less susceptible to infection (OR=0.60; 95% CI 0.25-1.47). Finally, from seroprevalence studies, with a total of 17,879 subjects involved, we estimated that children are 43% significantly less likely than adults to test positive for antibodies (OR=0.57; 95%CI: 0.49-0.68).

In conclusion, testing all subjects in schools, independently of symptoms, students less likely than adults favor viral spread and SARS-CoV-2 circulation in schools was found to be limited.

KEY POINTS

Question

What is the infectivity and susceptibility of students and staff exposed to SARS-CoV-2 in the school setting?

Findings

This systematic review and meta-analysis of all available data shows that SARS-CoV-2 viral spread is limited and child-to-adult transmission in the school setting scarce.

Summary estimates indicate that young index cases were 74% significantly less likely than adults to favor viral spread and children are 43% less susceptible than adults.

Meaning

Overall, SARS-CoV-2 circulation in schools was limited and could be reasonably controlled with appropriate mitigation measures.
PIPENN: Protein Interface Prediction with an Ensemble of Neural Nets
Authors: Stringer Bas , de Ferrante Hans , Abeln Sanne , Heringa Jaap , Feenstra K. Anton , Haydarlou Reza
Published: September 2021

Motivation

Protein interactions play an essential role in many biological and cellular processes, such as protein–protein interaction (PPI) in signaling pathways, binding to DNA in transcription, and binding to small molecules in receptor activation or enzymatic activity. Experimental identification of protein binding interface residues is a time-consuming, costly, and challenging task. Several machine learning and other computational approaches exist which predict such interface residues. Here we explore if Deep Learning (DL) can be used effectively for this prediction task, and which learning strategies and architectures may be most efficient. We introduce seven DL architectures that are applied to eleven independent test sets, focused on the residues involved in PPI interfaces and in binding RNA/DNA and small molecule ligands.

Results

We constructed a large data set dubbed BioDL, comprising protein-protein interaction data from the PDB and protein-ligand interactions (DNA, RNA and small molecules) from the BioLip database. Additionally, we reused our existing curated homo- and heteromeric PPI data sets. We performed several experiments to assess the impact of different data features, spatial forms, encoding schemes, network initializations, loss functions, regularization mechanisms, and activation functions on the performance of the predictors. Benchmarking the resulting DL models with an independent test set (ZK448) shows no single DL architecture performs best on all instances, but that an ensemble of DL architectures consistently achieves peak prediction performance. Our PIPENN’s ensemble predictor outperforms current state-of-the-art sequence-based protein interface predictors on all interaction types, achieving AUCs of 0.718 (protein–protein), 0.823 (protein–nucleotide) and 0.842 (protein– small molecule) respectively.

Availability

Source code and data sets at https://github.com/ibivu/pipenn/

Contact

r.haydarlou@vu.nl
Drug targeting to sites of oxidative stress using the Baeyer-Villiger reaction
Authors: Avery Thomas D , Li Jiahe , Turner Dion J. L. , Cherry Fisher R. , Ur Rasheed Mohd S. , Aguilar Clarissa , Shepherd Andrew J. , Yu Jingxian , Grace Peter M , Abell Andrew D
Published: September 2021

The antioxidant nuclear factor erythroid 2-related factor 2 (Nrf2) is a desirable therapeutic target for a broad range of pathologies, including chronic diseases of the lung and liver, and autoimmune, neurodegenerative, and cardiovascular disorders. However, current Nrf2 activators are limited by unwanted effects due to non-specificity, and systemic distribution and action. Here we report that a 1,2-dicarbonyl moiety masks the electrophilic reactivity of the Nrf2 activator monomethyl fumarate (MMF), otherwise responsible for its non-specific effects. The 1,2-dicarbonyl compound is highly susceptible to Baeyer-Villiger oxidation, with generation of MMF specifically on exposure to pathological levels of hydrogen peroxide or peroxynitrite. Oral treatment with the MMF generating 1,2-dicarbonyl compound reversed chronic neuropathic and osteoarthritis pain in mice, and selectively activated Nrf2 at sites of oxidative stress. This 1,2-dicarbonyl platform may be used to treat additional disorders of oxidative stress, and to selectively target other therapeutics to sites of redox imbalance.
Optimization of closed-loop electrical stimulation enables robust cerebellar-directed seizure control
Authors: Stieve Bethany J. , Richner Thomas J. , Krook-Magnuson Chris , Netoff Theoden I. , Krook-Magnuson Esther
Published: September 2021

Additional treatment options for temporal lobe epilepsy are needed, and potential interventions targeting the cerebellum are of interest. Previous animal work has shown strong inhibition of hippocampal seizures through on-demand optogenetic manipulation of the cerebellum. However, decades of work examining electrical stimulation – a more immediately translatable approach – targeting the cerebellum has produced very mixed results. We were therefore interested in exploring the impact that stimulation parameters may have on seizure outcomes. Using a mouse model of temporal lobe epilepsy, we conducted on-demand electrical stimulation of the cerebellar cortex, and varied stimulation charge, frequency, and pulse width, resulting in over a thousand different potential combinations of settings. To explore this parameter space in an efficient, data-driven, manner, we utilized Bayesian optimization with Gaussian process regression, implemented in Matlab with an Expected Improvement Plus acquisition function. We examined two different fitting conditions and two different electrode orientations. Following the optimization process, we conducted additional on-demand experiments to test the effectiveness of selected settings. Across all animals, we found that Bayesian optimization allowed identification of effective intervention settings. Additionally, generally similar optimal settings were identified across animals, suggesting that personalized optimization may not always be necessary. While optimal settings were consistently effective, stimulation with settings predicted from the Gaussian process regression to be ineffective failed to provide seizure control. Taken together, our results provide a blueprint for exploration of a large parameter space for seizure control, and illustrate that robust inhibition of seizures can be achieved with electrical stimulation of the cerebellum, but only if the correct stimulation parameters are used.
Durability analysis of the highly effective BNT162b2 vaccine against COVID-19
Authors: Puranik Arjun , Lenehan Patrick J. , O’Horo John C. , Niesen Michiel J.M. , Virk Abinash , Swift Melanie D. , Kremers Walter , Venkatakrishnan A.J. , Gordon Joel E. , Geyer Holly L. , Speicher Leigh Lewis , Soundararajan Venky , Badley Andrew D.
Published: September 2021

SARS-CoV-2 breakthrough infections have been increasingly reported in fully vaccinated individuals. We conducted a test-negative case-control study to assess the durability of protection after full vaccination with BNT162b2, defined as 14 days after the second dose, against polymerase chain reaction (PCR)-confirmed symptomatic SARS-CoV-2 infection, in a national medical practice between February 1, 2021 and August 22, 2021. We fit conditional logistic regression (CLR) models stratified on residential county and calendar time of testing to assess the association between time elapsed since vaccination and the odds of symptomatic infection or non-COVID-19 hospitalization (negative control), adjusted for several covariates. The primary population included 652 individuals who had a positive symptomatic test after full vaccination with BNT162b2 (cases) and 5,946 individuals with at least one negative symptomatic test after full vaccination (controls). The adjusted odds of symptomatic infection were higher 120 days after full vaccination versus at the date of full vaccination (Odds Ratio [OR]: 3.21, 95% confidence interval [CI]: 1.33-7.74). Importantly, the odds of infection were still lower 150 days after the first BNT162b2 dose as compared to 4 days after the first dose (OR: 0.3, 95% CI: 0.19-0.45), when immune protection approximates the unvaccinated status. Low rates of COVID-19 associated hospitalization or death in this cohort precluded analyses of these severe outcomes. The odds of experiencing a non-COVID-19 hospitalization decreased with time since vaccination, suggesting a possible underestimation of waning protection by this approach due to confounding factors. Taken together, these data constitute an early signal for waning protection against symptomatic illness while also providing reassurance that BNT162b2 continues to protect against symptomatic SARS-CoV-2 infection several months after full vaccination. Continued surveillance of COVID-19 vaccine durability, particularly against severe disease, is critical to guide effective and equitable strategies to respond to the pandemic, including distribution of booster doses, development of new vaccines, and implementation of both pharmaceutical and nonpharmaceutical interventions.
A comparison between time-constrained counts and line transects as methods to estimate butterfly diversity and monitor populations in tropical habitats
Authors: Suman Attiwilli , Ravikanthachari Nitin , Kunte Krushnamegh
Published: September 2021

Long-term species monitoring programmes have revealed catastrophic insect population declines and disruption of biological communities that are contributing to biodiversity loss. Such discoveries have been possible because of standardised methods, such as line transects, of counting butterflies and other insects. However, line transects are not feasible in many tropical and mountainous habitats, so alternative methods must be explored. To tackle this issue, we devised time-constrained (30-min) counts and compared butterfly diversity as estimated through this method with that estimated through line transects in three tropical habitats in India (evergreen forest, dry deciduous forest and an urban woodland). We tested the efficacy of the two methods to sample species richness and abundance, as well as numbers of rare, endemic and specialist butterflies. We observed greater species richness, and more species of habitat specialists and endemics per sample in time-constrained counts in evergreen forest, but not in the other two habitats. Thus, time-constrained counts were more efficient at detecting species in the species-rich evergreen habitat. Apart from this difference, the two sampling methods captured similar levels of species richness and other measures of diversity. Our study thus shows that time-constrained counts is a suitable if not a superior alternative to line transects to conduct butterfly diversity surveys and population monitoring in complex tropical landscapes. Due to methodological flexibility and simplicity, this method may be particularly useful to study the impacts of climate change, habitat fragmentation and land use practices on butterfly conservation in populous and tech-ready tropical countries using citizen science frameworks.
Exploring Intuitive Approaches to Protein Conformation Clustering Using Regions of High Structural Variance
Authors: Tan Yi Yao
Published: September 2021

This paper presents a method to find structurally high variance segments of the different conformations of a single protein and uses clusters them using different distance metrics and interpretation of coordinate and angle data presented by three different methods: root mean squared derivation RMSD, t-distributed Stochastic Neighbor Embedding (t-SNE) based map, and dihedral-based clustering. The methods were applied on the human cylin-dependent kinase 2 (CDK2) protein, code P24941 uniprot using a series of python scripts and clustering packages. We test our methods on the data of the CDK2 protein as it is a highly researched protein, with practical applications of clustering in cancer research, crucial in the regulation of the cell-cycle, and has a sizeable amount of experimental data collected on the confirmation structures.

While using the distance based root mean squared deviation RMSD provides data of structure to structure dissimilarity between different conformations, a simple RMSD matrix lacks to ability to describe the subsequence-wise in shape and absolute position which could be the main identifying elements for a protein’s conformation and state. To make up for this loss we explore an intuitive and more flexible method, able to accept multiple high structural variance segments, which takes coordinate based data, through a series of maps and with the help of t-SNE, and maps each segment as a feature in the clustering matrix. This method, however, would require additional testing on other proteins and modifications to verify its consistency and test its robustness.

In the end we explore the pros and cons of the three methods applied on the high structural variance regions. Despite the randomness factor by the t-SNE used in mapping the coordinates to lower dimensions, the coordinate-based approach consistently performed better than the RSMD and dihedral based methods in clustering the three groups of the CDK2 protein kinase. We also found that analyzing only the substructures identified by the high variance detection algorithm consistently provided more distinct clusters with higher multi-class F1 scores.
Spatiotemporal Modulations in Heterotypic Condensates of Prion and α-Synuclein Control Phase Transitions and Amyloid Conversion
Authors: Agarwal Aishwarya , Arora Lisha , Rai Sandeep K. , Avni Anamika , Mukhopadhyay Samrat
Published: September 2021

Biomolecular condensates formed via liquid-liquid phase separation (LLPS) of proteins and nucleic acids are thought to govern critical cellular functions. These multicomponent assemblies provide dynamic hubs for competitive homotypic and heterotypic interactions. Here, we demonstrate that the complex coacervation between the prion protein (PrP) and α-synuclein (α-Syn) within a narrow stoichiometry regime results in the formation of highly dynamic liquid droplets. Domain-specific electrostatic interactions between the positively charged intrinsically disordered N-terminal segment of PrP and the negatively charged C-terminal domain of α-Syn drive the formation of these highly tunable, reversible, thermo-responsive condensates. Picosecond time-resolved measurements revealed the existence of relatively ordered electrostatic nanoclusters that are stable on the nanosecond timescale and can undergo breaking-and-making on a much slower timescale giving rise to the liquid-like behavior on the second timescale and mesoscopic length-scale. The addition of RNA to these preformed coacervates yields multiphasic, anisotropic, vesicle-like, hollow condensates. LLPS promotes liquid-to-solid maturation of α-Syn-PrP condensates resulting in the rapid conversion into heterotypic amyloids. Our results suggest that synergistic interactions between PrP and α-Syn in liquid condensates can offer mechanistic underpinnings of their physiological role and overlapping neuropathological features.
Gut Reaction: The Impact of a Film on Public Understanding of Gastrointestinal Conditions
Authors: Gomes Diogo , Loth Alina , Hockley James R.F. , John Smith Ewan St.
Published: September 2021

Chronic gastrointestinal (GI) tract conditions, such as inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) are common conditions associated with disordered bowel movements and significant pain. However, discussion of bowel habits is often regarded as taboo and public understanding of what exactly IBD, IBS and related conditions are, and how they impact the lives of those individuals with such conditions is poorly understood. To provide a platform for enhancing public engagement of chronic bowel conditions, a short film was made (Gut Reaction) examining the lives of four individuals with different bowel conditions and what scientists and clinicians are doing to help alleviate the pain experienced by such individuals. This film was then screened at a science festival where a pre- and post-film survey was conducted alongside follow up semi-structured interviews with a small subset of those who had expressed willingness to engage in such an interview. Although films have been used for public engagement and health campaigns, there is a lack of a robust evaluation of such methods. As such, there is no knowledge of impacts and outcomes, jeopardising funding of such projects. Overall, the pre- and post-film surveys demonstrated that the film had increased the attendees’ understanding of chronic bowel conditions, how they are treated, what research is on-going and the likelihood of discussing bowel conditions with friends and family. The follow-up interviews were analysed through the constant comparative coding process. The analysis revealed that participants have a strong belief that bowel conditions need to be part of normal conversations, and the understanding of such conditions, and the people who experience them, needs to be improved by society. Our participants hold that this is crucial for people who experience from such conditions, not least to be able to access help sooner and suffer less. Finally, our participants discussed two strategies to achieve this societal openness and tackle the sense of shame around these issues: one involving role models and the other the media. In summary, Gut Reaction appeared to have met its objectives of improving the viewers’ awareness and understanding of chronic bowel conditions, as well as removing some of the stigma and taboo that surround discussions about these conditions.
Missing the forest for the trees: Do seaweed ecosystems mitigate atmospheric CO2 emissions?
Authors: Gallagher John Barry , Shelamoff Victor , Layton Cayne
Published: September 2021

Global seaweed carbon sequestration estimates are currently taken as the fraction of the net primary production (NPP) exported to the deep ocean. However, this perspective does not account for CO2 from the consumption of external subsidies. Here we clarify: i) the role of export relative to seaweed net ecosystem production (NEP) for a closed system and one more likely open to subsidies; ii) the importance of subsidies by compiling published estimates of NEP from seaweed-dominated ecosystems; and iii) discuss their impact on the global seaweed net carbon balance and other sequestration constraints as a mitigation service. Examples of seaweed NEP (n = 18) were sparse and variable. Nevertheless, the average NEP (−9.2mmol C m−2 day−1 SE ± 11.6) suggested that seaweed ecosystems are a C source, becoming increasingly heterotrophic as their export is consumed. Critically, mitigation of greenhouse gas emissions was mixed relative to their replacement or baseline states, and where CO2 is supplied independently of organic metabolism and atmospheric exchange we caution a sole reliance on NEP or NPP. This will ensure a more accurate seaweed mitigation assessment, one that does exceed their capacity and is effective within a compliance and carbon trading scheme.
Aversive memory formation in humans is determined by an amygdala-hippocampus phase code
Authors: Costa Manuela , Lozano-Soldevilla Diego , Gil-Nagel Antonio , Toledano Rafael , Oehrn Carina , Kunz Lukas , Yebra Mar , Mendez-Bertolo Costantino , Stieglitz Lennart , Sarnthein Johannes , Axmacher Nikolai , Moratti Stephan , Strange Bryan A.
Published: September 2021

Memory for aversive events is central to survival, but can also become maladaptive in psychiatric disorders. Emotional memory relies on the amygdala and hippocampus, but the neural dynamics of their communication during emotional memory encoding remain unknown. Using simultaneous intracranial recordings from both structures in human patients, we show that in response to emotionally aversive, but not neutral, visual stimuli, the amygdala transmits unidirectional influence on the hippocampus through theta oscillations. Critically, successful emotional memory encoding depends on the precise amygdala theta phase to which hippocampal gamma activity and neuronal firing couple. The phase difference between subsequently remembered vs. not-remembered emotional stimuli translates to ∼25-45 milliseconds, a time period that enables lagged coherence between amygdala and downstream hippocampal gamma activity. These results reveal a mechanism whereby amygdala theta phase coordinates transient coherence between amygdala and hippocampal gamma activity to facilitate the encoding of aversive memories in humans.
'Lose-to-gain' adaptation to genome decay in the structure of the smallest eukaryotic ribosomes
Authors: Nicholson David , Salamina Marco , Panek Johan , Helena-Bueno Karla , Brown Charlotte R , Hirt Robert P , Ranson Neil A , Melnikov Sergey V
Published: September 2021

The evolution of microbial parasites involves the interplay of two opposing forces. On the one hand, the pressure to survive drives parasites to improve through Darwinian natural selection. On the other, frequent genetic drifts result in genome decay, an evolutionary process in which an ever-increasing burden of deleterious mutations leads to gene loss and gradual genome reduction. Here, seeking to understand how this interplay occurs at the scale of individual macromolecules, we describe cryo-EM and evolutionary analyses of ribosomes from Encephalitozoon cuniculi, a eukaryote with one of the most reduced genomes in nature. We show that E. cuniculi ribosomes, the smallest eukaryotic cytoplasmic ribosomes to be structurally characterized, employ unparalleled structural innovations that allow extreme rRNA reduction without loss of ribosome integrity. These innovations include the evolution of previously unknown rRNA features such as molten rRNA linkers and bulgeless rRNA. Furthermore, we show that E. cuniculi ribosomes withstand the loss of rRNA and protein segments by evolving a unique ability to effectively trap small molecules and use them as ribosomal building-blocks and structural mimics of degenerated rRNA and protein segments. Overall, our work reveals a recurrent evolutionary pattern, which we term 'lose-to-gain' evolution, where it is only through the loss of rRNA and protein segments that E. cuniculi ribosomes evolve their major innovations. Our study shows that the molecular structures of intracellular parasites long viewed as reduced, degenerated, and suffering from various debilitating mutations instead possess an array of systematically overlooked and extraordinary structural features. These features allow them to not only adapt to molecular reduction but evolve new activities that parasites can possibly use to their advantage.
Promyelocytic leukemia nuclear body (PML-NB) -free intranuclear milieu facilitates development of oocytes in mice
Authors: Udagawa Osamu , Kato-Udagawa Ayaka , Hirano Seishiro
Published: September 2021

Promyelocytic leukemia (PML) nuclear bodies (PML-NBs), a class of membrane-less organelles in cells, are involved in multiple biological activities and are present throughout cells of adult organisms. Although the oocyte nucleus is an active region for the flux of multiple non-membranous organelles, PML-NBs have been predicted to be absent from oocytes. Here, we show that the deliberate assembly of PML-NBs during oocyte growth preferentially sequestered Small Ubiquitin-related Modifier (SUMO) protein from the nucleoplasm. SUMO not only was involved in the regulation of oocyte nuclear maturation but also was committed to the response, mediated by liquid droplet formation, to multiple stressors including nucleolar stress and proteotoxic stresses. Exogenous assembly of PML-NBs in the nucleus of oocytes affected the efficiency of the response of SUMO. These observations suggest that the PML-NB-free intranuclear milieu ensures that a reserve of SUMO remains available for emergent responses in oocyte development. This work demonstrated a benefit of the PML-NB-free intranuclear milieu, namely the ability to redirect the flux of SUMO otherwise needed to control PML-NB dynamics.
HLA class II mediates type 1 diabetes risk by anti-insulin repertoire selection
Authors: García Arcadio Rubio , Paterou Athina , Lee Mercede , Sławiński Hubert , Ferreira Ricardo , Landry Laurie G , Trzupek Dominik , Teyton Luc , Szypowska Agnieszka , Wicker Linda S , Nakayama Maki , Todd John A , Pękalski Marcin Ł
Published: September 2021

Type 1 diabetes (T1D) is a common autoimmune disorder characterized by the destruction of insulin-secreting pancreatic β cells [1], in which polymorphism of the human leukocyte antigen (HLA) class II region is the major genetic risk factor [2, 3, 4]. However, how variation in class II molecules alters T1D risk remains a longstanding question. Here we show how T1D risk due to HLA class II haplotype combinations [5] correlates with the frequency of negatively charged sequences in the CDR3β region of CD4+T cell receptor (TCR) repertoires purified from peripheral blood. These sequences are known to be common in receptors that bind insulin B:9–23 [6], the primary autoantigen in T1D. We also show the same effect in circulating activated CD4+T cells from newly-diagnosed T1D cases, and in islet-infiltrating T cells from patients with active T1D. Furthermore, we demonstrate that the proportion of insulin-reactive CD4+T cells present in islets is predicted by the frequency of these negatively charged CDR3β amino acid sequences. Our results suggest diagnostic uses of T cell repertoire profiling in early detection of insulin autoimmunity, and inform ongoing efforts to improve tolerance induction to insulin and prevention of T1D [7].
NR0B2 regulation during Primary Sclerosing Cholangitis defines a metabolic and pre-malignant reprogramming of Cholangiocyte
Authors: Desterke Christophe , Feray Cyrille
Published: September 2021

Primary Sclerosing Cholangitis (PSC) is an idiopathic, cholestatic liver disease that is characterized by persistent, progressive, biliary inflammation leading to cirrhosis. These patients present higher risk for developing bile duct cancers.

Biomedical text-mining related to PSC symptoms like: biliary inflammation, biliary fibrosis, biliary cholestasis was initiated to collect gene associations with this pathophysiology. The text mining work was integrated in distinct omics data such as human transcriptome of PSC liver, Farnesoid X receptor (FXR) functional liver transcriptome and liver single cell transcriptome of the Abcb4-/- model of PSC. A molecular network implicated in abnormal hepatobiliary system physiology was built and confirming a major implication of Nr0b2 and its associated nuclear receptors like FXR in a metabolic cascade that could influence immune response. TNFRSF12A/TWEAK receptor, was found up regulated in PSC liver independently of FXR regulation and TWEAK signaling is known for its implication in pre-conditioning niche of cholangiocarcinoma. NR0B2 deregulation in PSC liver was found independent of gender, age and body mass index surrogates. At single cell level, Nr0b2 up regulation was found in cholangiocytes but not in hepatocytes. In affected cholangiocytes, the cell trajectory built on Nr0b2 expression, revealed implication of several metabolic pathways for detoxification like sulfur, glutathione derivative and monocarboxylic acid metabolisms. On this cell trajectory it was discovered some molecules potentially implicated in carcinogenesis like: GSTA3, ID2 and mainly TMEM45A a transmembrane molecule from golgi apparatus considered as oncogene in several cancers. All together, these observations found in humanPSC liver and in its murine models allowed to highlight an independent deregulation of NR0B2 with a metabolic and premalignant reprogramming of cholangiocytes.
Fast wavefront shaping for two-photon brain imaging with large field of view correction
Authors: Blochet Baptiste , Akemann Walther , Gigan Sylvain , Bourdieu Laurent
Published: September 2021

Introduction paragraph

In-vivo optical imaging with diffraction-limited resolution deep inside scattering biological tissues is obtained by non-linear fluorescence microscopy1. Active compensation of tissue-induced aberrations and light scattering through adaptive wavefront correction2,3 further extends depth penetration by restoring high resolution at large depth. However, at large depths those corrections are only valid over a very limited field of view within the angular memory effect4. To overcome this limitation, we introduce an acousto-optic light modulation technique for fluorescence imaging with simultaneous wavefront correction at pixel scan speed. Biaxial wavefront corrections are first learned by adaptive optimization at multiple locations in the image field. During image acquisition, the learned corrections are then switched on-the-fly according to the position of the excitation focus during the raster scan. The proposed microscope is applied to in-vivo transcranial neuron imaging and demonstrates correction of skull-induced aberrations and scattering across large fields of view at 40 kHz data acquisition speed.
Analysis of Rod/Cone Gap Junctions from the Reconstruction of Mouse Photoreceptor Terminals
Authors: Ishibashi Munenori , Keung Joyce , Morgans Catherine W. , Aicher Sue A. , Carroll James R. , Singer Joshua H. , Jia Li , Li Wei , Fahrenfort Iris , Ribelayga Christophe P. , Massey Stephen C.
Published: September 2021

Using serial blockface-scanning electron microscopy (SBF-SEM) and focused ion beam-scanning electron microscopy (FIB-SEM), combined with confocal microscopy for the gap junction protein Cx36, we reconstructed mouse photoreceptor terminals and located the gap junctions between them. An exuberant spray of fine telodendria extends from each cone pedicle (including blue cones) to contact 40-50 nearby rod spherules where Cx36 clusters were located, close to the mouth of the synaptic opening. There were approximately 50 Cx36 clusters per cone pedicle and 2-3 per rod spherule. We were unable to detect rod/rod or cone/cone coupling. Thus, rod/cone coupling accounts for nearly all gap junctions between photoreceptors. Our calculations suggest a mean of 82 Cx36 channels between a rod/cone pair of which 25% are open at rest. Rod/cone gap junctions are modulated by dopamine. Comparing our morphological calculations of maximum coupling to previous physiological results suggests that dopamine antagonists can drive rod/cone gap junctions to a surprisingly high open probability, approaching 100%.
Aging is associated with increased brain iron through brain-derived hepcidin expression
Authors: Sato Tatsuya , Shapiro Jason , Chang Hsiang-Chun , Miller Richard A. , Ardehali Hossein
Published: September 2021

Iron is an essential molecule for biological processes, but its accumulation can lead to oxidative stress and cellular death. Due to its oxidative effects, iron accumulation is implicated in the process of aging and neurodegenerative diseases. However, the mechanism for this increase in iron with aging, and whether this increase is localized to specific cellular compartment(s), are not known. Here, we measured the levels of iron in different tissues of aged mice, and demonstrate that while cytosolic non-heme iron is increased in the liver and muscle tissue, only the aged brain exhibits an increase in both the cytosolic and mitochondrial non-heme iron. This increase in brain iron is associated with elevated levels of local hepcidin mRNA and protein in the brain. We also demonstrate that the increase in hepcidin is associated with increased ubiquitination and reduced levels of the only iron exporter, feroportin-1 (FPN1). Overall, our studies provide a potential mechanism for iron accumulation in the brain through increased local expression of hepcidin, and subsequent iron accumulation due to decreased iron export. Additionally, our data support that aging is associated with mitochondrial and cytosolic iron accumulation only in the brain and not in other tissues.
Legionella pneumophila regulates host cell motility by targeting Phldb2 with a 14-3-3ζ-dependent protease effector
Authors: Song Lei , Luo Jingjing , Huang Dan , Tan Yunhao , Liu Yao , Yu Kaiwen , Zhang Yong , Liu Xiaoyun , Li Dan , Luo Zhao-Qing
Published: September 2021

The cytoskeleton network of eukaryotic cells is essential for diverse cellular processes, including vesicle trafficking, cell motility and immunity, thus is a common target for bacterial virulence factors. A number of effectors from the bacterial pathogen Legionella pneumophila have been shown to modulate the function of host actin cytoskeleton to construct the Legionella-containing vacuole (LCV) permissive for its intracellular replication. In this study, we identified the Dot/Icm effector Lem8 (Lpg1290) as a protease that interferes with host motility. We show that the protease activity of Lem8 is catalyzed by a Cys-His-Asp motif known to be associated with diverse biochemical activities. Intriguingly, we found that Lem8 interacts with the host regulatory protein 14-3-3ζ, which activates its protease activity. Furthermore, Lem8 undergoes self-cleavage in a process that requires 14-3-3ζ. We identified the PH domain-containing protein Phldb2 involved in cell migration as a target of Lem8 and demonstrate that Lem8 plays a role in the inhibition of host cell migration. Our results reveal a novel mechanism of inhibiting host cell motility by L. pneumophila for its virulence.
Sequestration and efflux largely account for cadmium and copper resistance in the deep sea epsilonproteobacterium, Nitratiruptor sp. SB155-2
Authors: Ares Ángela , Sakai Sanae , Sasaki Toshio , Mitarai Satoshi , Nunoura Takuro
Published: September 2021

In deep sea hydrothermal vent environments, metal- and metalloid-enriched fluids and sediments abound, making these habitats ideal to study metal resistance in prokaryotes. In this investigation, the architecture of the epsilonproteobacterium, Nitratiruptor sp. SB155-2 transcriptome in combination with sub-cellular analysis using scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy (STEM-EDX) was examined to better understand mechanisms of tolerance for cadmium (Cd) and copper (Cu) at stress-inducing concentrations. Transcriptomic expression profiles were remarkably different in the presence of these two metals, displaying 385 (19%) and 629 (31%) genes differentially expressed (DE) in the presence of Cd and Cu, respectively, while only 7% of DE genes were shared, with genes for non-specific metal transporters and genes involved in oxidative stress-response predominating. The principal metal-specific DE pathways under Cu stress, including those involving sulfur, cysteine, and methionine, are likely required for high-affinity efflux systems, while flagella formation and chemotaxis were over-represented under Cd stress. Consistent with these differences, STEM-EDX analysis revealed that polyphosphate-like granules (pPLG), the formation of CdS particles, and the periplasmic space may be crucial for Cd sequestration. Overall, this study provides new insights regarding metal-specific adaptations of Epsilonproteobacteria to deep sea hydrothermal vent environments.

Significance originality statement

Deep sea hydrothermal vents are unique environments in which metals and metalloids abound. Despite being a dominant phylum in these environments, adaptations enabling Epsilonproteobacteria to thrive in metal-rich environments remain poorly understood. In this study, a combination of high-throughput, whole-transcriptome RNA-seq analysis, scanning transmission electron microscopy, and energy-dispersive X-ray spectroscopy provide a comprehensive picture of molecular and morphological adaptations controlling metal efflux and sequestration systems of this bacterium in response to cadmium and copper. Many of these responses are metal-specific.
The NDNF-like factor Nord is a Hedgehog-induced extracellular BMP modulator that regulates Drosophila wing patterning and growth
Authors: Yang Shu , Wu Xuefeng , Daoutidou Euphrosyne I. , Zhang Ya , Shimell MaryJane , Chuang Kun-Han , Peterson Aidan J. , O’Connor Michael B. , Zheng Xiaoyan
Published: September 2021

Hedgehog (Hh) and bone morphogenetic proteins (BMPs) pattern the developing Drosophila wing by functioning as short- and long-range morphogens, respectively. Here, we show that a previously unknown Hh-dependent mechanism fine-tunes the activity of BMPs. Through genome-wide expression profiling of the Drosophila wing imaginal discs, we identify nord as a novel target gene of the Hh signaling pathway. Nord is related to the vertebrate Neuron Derived Neurotrophic Factor (NDNF) involved in Congenital Hypogonadotropic Hypogonadism and several types of cancer. Loss- and gain-of-function analyses implicate Nord in the regulation of wing growth and proper crossvein patterning. At the molecular level, we present biochemical evidence that Nord is a secreted BMP-binding protein and localizes to the extracellular matrix. Nord binds to Decapentaplegic (Dpp) or the heterodimer Dpp-Glass bottom boat (Gbb) to modulate their release and activity. Furthermore, we demonstrate that Nord is a dosage-depend biphasic BMP modulator, where low levels of Nord promote and high levels inhibit BMP signaling. Taken together, we propose that Hh-induced Nord expression fine tunes both the range and strength of BMP signaling in the developing Drosophila wing.

One sentence summary

The NDNF-like factor Nord is a Hedgehog-induced and extracellular-localized biphasic BMP modulator that regulates Drosophila wing patterning and growth
HTSplotter: an end-to-end data processing, analysis and visualisation tool for chemical and genetic in vitro perturbation screening
Authors: Nunes Carolina , Anckaert Jasper , De Vloed Fanny , De Wyn Jolien , Durinck Kaat , Vandesompele Jo , Speleman Frank , Vermeirssen Vanessa
Published: September 2021

In biomedical research, high-throughput screening is often applied as it comes with automatization, higher-efficiency, and more and faster results. High-throughput screening experiments encompass drug, drug combination, genetic perturbagen or a combination of genetic and chemical perturbagen screens. These experiments are conducted in real-time assays over time or in an endpoint assay. The data analysis consists of data cleaning and structuring, as well as further data processing and visualisation, which, due to the amount of data, can easily become laborious, time consuming and error-prone. Therefore, several tools have been developed to aid researchers in this process, but these typically focus on specific experimental set-ups and are unable to process data of several time points and genetic-chemical perturbagen screens. To meet these needs, we developed HTSplotter, available as web tool and Python module, which performs automatic data analysis and visualisation of either endpoint or real-time assays from different high-throughput screening experiments: drug, drug combination, genetic perturbagen and genetic-chemical perturbagen screens. HTSplotter implements an algorithm based on conditional statements in order to identify experiment type and controls. After appropriate data normalization, including growth rate normalization, HTSplotter executes downstream analyses such as dose-response relationship and drug synergism assessment by the Bliss independence (BI), Zero Interaction Potency (ZIP) and Highest Single Agent (HAS) methods. All results are exported as a text file and plots are saved in a PDF file. The main advantage of HTSplotter over other available tools is the automatic analysis of genetic-chemical perturbagen screens and real-time assays where growth rate and perturbagen effect results are plotted over time. In conclusion, HTSplotter allows for the automatic end-to-end data processing, analysis and visualisation of various high-throughput in vitro cell culture screens, offering major improvements in terms of versatility, efficiency and time over existing tools.
Transcriptional signatures of cell-cell interactions are dependent on cellular context
Authors: Innes Brendan T. , Bader Gary D.
Published: September 2021

Cell-cell interactions are often predicted from single-cell transcriptomics data based on observing receptor and corresponding ligand transcripts in cells. These predictions could theoretically be improved by inspecting the transcriptome of the receptor cell for evidence of gene expression changes in response to the ligand. It is commonly expected that a given receptor, in response to ligand activation, will have a characteristic downstream gene expression signature. However, this assumption has not been well tested. We used ligand perturbation data from both the high-throughput Connectivity Map resource and published transcriptomic assays of cell lines and purified cell populations to determine whether ligand signals have unique and generalizable transcriptional signatures across biological conditions. Most of the receptors we analyzed did not have such characteristic gene expression signatures – instead these signatures were highly dependent on cell type. Cell context is thus important when considering transcriptomic evidence of ligand signaling, which makes it challenging to build generalizable ligand-receptor interaction signatures to improve cell-cell interaction predictions.
A cellular and molecular atlas reveals the basis of chytrid development
Authors: Laundon Davis , Chrismas Nathan , Bird Kimberley , Thomas Seth , Mock Thomas , Cunliffe Michael
Published: September 2021

The chytrids (phylum Chytridiomycota) are a major early-diverging fungal lineage of ecological and evolutionary importance. Despite their importance, many fundamental aspects of chytrid developmental and cell biology remain poorly understood. To address these knowledge gaps, we combined quantitative volume electron microscopy and comparative transcriptome profiling to create an ‘atlas’ of the cellular and molecular basis of the chytrid life cycle, using the model chytrid Rhizoclosmatium globosum. From our developmental atlas, we show that zoospores exhibit a specialised biological repertoire dominated by inactive ribosome aggregates, and that lipid processing is complex and dynamic throughout the cell cycle. We demonstrate that the chytrid apophysis is a distinct subcellular structure characterised by high intracellular trafficking, providing evidence for division of labour in the chytrid cell plan, and show that zoosporogenesis includes ‘animal like’ amoeboid cell morphologies resulting from endocytotic cargo transport from the interstitial maternal cytoplasm. Taken together, our results reveal insights into chytrid developmental biology and provide a basis for future investigations into early-diverging fungal cell biology.