bluuebunny/crossref_metadata_2025 huggingface dataset:
Redox regulation of Kv7 channels through EF3 hand of calmodulin
Authors: Nuñez Eider , Jones Frederick , Muguruza-Montero Arantza , Urrutia Janire , Aguado Alejandra , Malo Covadonga , Bernardo-Seisdedos Ganeko , Domene Carmen , Millet Oscar , Gamper Nikita , Villarroel Alvaro
Published: September 2022

Neuronal KV7 channels, important regulators of cell excitability, are among the most sensitive proteins to reactive oxygen species. The S2S3 linker of the voltage sensor was reported as a site mediating redox modulation of the channels. Recent structural insights reveal potential interactions between this linker and the Ca2+-binding loop of the third EF-hand of calmodulin (CaM), which embraces an antiparallel fork formed by the C-terminal helices A and B. We found that precluding Ca2+ binding to the EF3 hand, but not to EF1, EF2 or EF4 hands, abolishes oxidation-induced enhancement of Kv7.4 currents. Monitoring FRET between helices A and B tagged with fluorescent proteins, we observed that S2S3 peptides cause a reversal of the signal in the presence of Ca2+, but have no effect in the absence of this cation or if the peptide is oxidized. The capacity of loading EF3 with Ca2+ is essential for this reversal of the FRET signal, whereas the consequences of obliterating Ca2+ binding to EF1, EF2 or EF4 are negligible. Furthermore, we show that EF3 is necessary and sufficient to translate Ca2+ signals to reorient the AB fork. Our data is consistent with the proposal that oxidation of cysteine residues in the S2S3 loop relieves Kv7 channels from a constitutive inhibition imposed by interactions between the EF3 hand of CaM which is necessary and sufficient for this signaling.

Significance

Oxidation-dependent enhancement of the KV7/M-channels plays a cytoprotective role in neurons. Here, we show that calmodulin (CaM), the main protein that conveys information from transient intracellular Ca2+ oscillations, plays a critical role in oxidative signal transduction. The prevailing view is that the main role of the EF-hands is to respond to Ca2+ and that the two EF-hands of CaM in each lobe act in coordination during signaling. We find that EF3 by itself is sufficient and necessary for the oxidative response of Kv7 channel complex and for gating the Calcium Responsive Domain of Kv7 channels. In addition, the direction of EF3-dependent signaling can be reversed by protein-protein interactions with solvent exposed regions outside the target binding groove between EF-hands.
Evolutionary trajectories are contingent on mitonuclear interactions
Authors: Biot-Pelletier Damien , Bettinazzi Stefano , Gagnon-Arsenault Isabelle , Dubé Alexandre K. , Bédard Camille , Nguyen Tuc H. M. , Fiumera Heather L. , Breton Sophie , Landry Christian R.
Published: September 2022

Critical mitochondrial functions, including cellular respiration, rely on frequently interacting components expressed from both the mitochondrial and nuclear genomes. The fitness of eukaryotic organisms depends on a tight collaboration between both genomes. In the face of an elevated rate of evolution in the mitochondrial genome, current models predict that maintenance of mitonuclear compatibility relies on compensatory evolution of the nuclear genome. Mitonuclear interactions would therefore exert an influence on evolutionary trajectories. One prediction from this model is that the same nuclear genomes but evolving with different mitochondrial haplotypes would follow distinct molecular paths towards higher fitness peaks. To test this prediction, we submitted 1344 populations derived from seven mitonuclear genotypes ofSaccharomyces cerevisiaeto more than 300 generations of experimental evolution in conditions that either select for a mitochondrial function, or that do not strictly require respiration for survival. Performing high-throughput phenotyping and whole-genome sequencing on independently evolved individuals isolated from endpoint populations, we identified numerous examples of gene-level evolutionary convergence among populations with the same mitonuclear background. Phenotypic and genotypic data on strains derived from this evolution experiment identify the nuclear genome and the environment as the main determinants of evolutionary divergence, but also show a modulating role for the mitochondrial genome exerted both directly and via interactions with the two other components. We finally recapitulated a subset of prominent loss-of-function alleles in the ancestral backgrounds and confirmed a generalized pattern of mitonuclear-specific and highly epistatic fitness effects. Together, these results demonstrate how mitonuclear interactions can dictate evolutionary divergence of populations with identical starting nuclear genotypes.
Phosphorylation of Gαi shapes canonical Gα(i)βγ/GPCR signaling
Authors: Roy Suchismita , Sinha Saptarshi , Silas Ananta James , Ghassemian Majid , Kufareva Irina , Ghosh Pradipta
Published: September 2022

A long-standing question in the field of signal transduction is to understand the interplay between distinct signaling pathways that control cell behavior. For growth factors and heterotrimeric G proteins, the two major signaling hubs in eukaryotes, the mechanisms of independent signal transduction have been extensively characterized; however, if/how they may cross talk remains obscure. Here we use linear-ion-trap mass spectrometry in combination with cell-based biophysical, biochemical, and phenotypic assays to chart at least three distinct ways in which growth factors may impact canonical Gα(i)βγ signaling downstream of a GPCR (CXCR4) via phosphorylation of Gαi. Phosphomimicking mutations in a cluster of residues in the αE helix (Y154/Y155) result in the suppression of agonist-induced Gα(i) activation while promoting constitutive Gβγ signaling; others in the P-loop (Ser44, Ser47, Thr48) suppress Gi activation entirely thus completely segregating the growth factor and GPCR pathways. While most phosphoevents appear to impact, as expected, the core properties of Gα(i) (conformational stability, nucleotide binding, Gβγ association and release, etc.), one phosphomimicking mutation promoted mislocalization of Gαi from the plasma membrane: a novel and unexpected mechanism of GPCR signal suppression. A phosphomutation of C-terminal Y320was sufficient to orchestrate such suppression by protein compartmentalization. Findings not only elucidate how growth factor and chemokine signals crosstalk through phosphomodulation of Gαi, but also how such crosstalk may generate signal diversity.
Practical scan-length considerations for mapping upper limb movements to the somatosensory/motor cortex at 7T
Authors: Rangaprakash D , Rowe Olivia E , Song Hyungeun , Gutierrez-Arango Samantha , Fernandez Michael F , Israel Erica A , Herr Hugh M , Barry Robert L
Published: September 2022

The relationship between motor cortex (M1) and upper limb movements has been investigated extensively using functional MRI (fMRI). While most research has focused on applications, very few studies have focused on practical aspects related to developing the fMRI protocol. Thus, the effect of scan length on M1 activations during various upper limb movements remains unclear. Scan length constraints are important for conducting motor experiments within a 60- or 90-min scan session. We targeted this gap by studying 7T fMRI activations in a male participant while performing eight different upper limb movements (of the fingers, wrist, and elbow) across 16 task runs (8 with the left arm, 8 with the right arm, 88 mins total fMRI duration). Standard activation analyses were performed (Z>3.1, p<0.01, cluster thresholded) independently for 14 different cases (2 runs through 8 runs, left and right arm) and compared. We found diminishing returns with higher number of runs (activations gradually plateaued with runs). We observed two clusters of movements, one with generally higher activation (more activated voxels and higher Z-stats) and the other with lower activation. To achieve similar statistical power, movements with lower activation required longer scanning (more runs). Based on these observations, we propose a ‘one size does not fit all’ practical protocol within a 60-, 75-, or 90-min scan session, wherein different number of runs are assigned for different movements. Our study could benefit researchers who are designing upper limb fMRI experiments.
The parthenogenesis mechanism and venom complement of the parasitoid wasp Microctonus hyperodae, a declining biocontrol agent
Authors: Inwood Sarah N. , Harrop Thomas W.R. , Dearden Peter K.
Published: September 2022

A biocontrol system in New Zealand using the endoparasitoid Microctonus hyperodae is failing, despite once being one of the most successful examples of classical biocontrol worldwide. In this study, RNA-seq was used to characterise two key traits of M. hyperodae in this system, the venom complement, critical for the initial success of biocontrol, and the asexual reproduction, which influenced the decline. Full characterisation of M. hyperodae venom revealed 82 candidate venom transcripts with both signal peptides and significantly higher expression in venom. Among these were many involved in manipulating the host environment to source nutrition for the parasitoid egg, preventing a host immune response against the egg, as well as two components that may stimulate the host’s innate immune system. Notably lacking from this list was calreticulin, as it also had high expression in the ovaries. In-situ hybridisation revealed expression was localised to the follicle cells, which may result in the deposition of calreticulin into the egg exochorion. Investigating the asexual reproduction of M. hyperodae revealed core meiosis-specific genes had conserved expression patterns with the highest expression in the ovaries, suggesting M. hyperodae parthenogenesis involves meiosis and the potential for sexual reproduction may have been retained. Upregulation of genes involved in endoreduplication provides a potential mechanism for the restoration of diploidy in eggs after meiosis.
Epiphenomenal neural activity in the primate cortex
Authors: Tremblay Sébastien , Testard Camille , Inchauspé Jeanne , Petrides Michael
Published: September 2022

When neuroscientists record neural activity from the brain, they often conclude that neural responses observed during task performance are indicative of the functional role of the brain area(s) studied. In humans and nonhuman primates, it is often hard to combine recordings and causal techniques within the same experiment, leaving the possibility that the activity recorded may be epiphenomenal rather than reflecting a specific functional role. Currently, the prevalence of epiphenomenal neural activity in the cortex is unknown. To estimate the extent of such activity in primates, we chronically recorded neural activity in the prefrontal cortex of the same monkeys using the same neural implants during the performance of four different cognitive tasks. The four tasks were carefully selected such that only one of them causally depends on the brain area recorded, as demonstrated by previous double dissociation studies. Using the four most common single neuron analyses methods in the field, we found that the prevalence and strength of neural correlates were just as high across all four tasks, including for the three tasks that do not depend on this brain area. These results suggest that the probability of observing epiphenomenal activity in primate cortex is high, which can mislead investigators relying on neural recording or imaging to map brain function.

One-Sentence Summary

Tremblay, Testard and colleagues show that inferring a brain area’s function from neural recordings alone could be misleading.
Camel urine limits proliferation and modifies cell morphology in human renal tumoral and non-tumoral cells
Authors: Pastrana Carlos Iglesias , Sgobba Maria Noemi , Navas González Francisco Javier , Delgado Bermejo Juan Vicente , Duarte Iola F. , Lentini Giovanni , Sayed Osman Taher Kamal , Guerra Lorenzo , Ciani Elena
Published: September 2022

The widespread ethnomedical practice of dromedary urinotherapy as a remedy against various illnesses is well recognized in traditional dromedary countries, and multiple researchers tried to unravel its bioactive potential and provide scientific evidence through in vivo and in vitro experiments. None of these studies (i) measured urine osmolarity prior to bioactivity testing, which could deeply influence the results of in vitro tests, nor (ii) addressed issues related to cells’ morphological changes after exposure to camel urines. Taken together, the above aspects point to the need for a “good practice” to be shared by researchers in this field, in order to reduce the variability of in vitro testing of camel urine bioactivity. In this work, using a set of biological samples from animals differing in sex, age, and physiological status, we investigated, the antiproliferative activity of camel urine towards human non-tumoral (HK2) and tumoral renal cells (Caki-1), through cell viability and microscopy analysis, and taking the possible influence of osmolarity into account. We employed cell lines commonly used in toxicological research which, to the best of our knowledge, have not been previously exposed to camel urine. HK2 and Caki-1 cells tolerated well mannitol-induced hyperosmolarity up to 500 mOsm/L. Significant antiproliferative effects were observed only in Caki-1 cells, when exposed to urine solutions (diluted to <500 mOsm/L) from two males out of the ten tested samples, while effects on cell morphology (elongation) were observed only in HK2 cells, when exposed to urine solutions from six samples. The significant antiproliferative effect observed only in tumoral cells looks promising for forthcoming developments in the cancer treatment field. Finally, the presented approach may serve as a guide for future research in this specific, multidisciplinary field.
Discovery and characterization of LNCSOX17 as an essential regulator in human endoderm formation
Authors: Landshammer Alexandro , Bolondi Adriano , Kretzmer Helene , Much Christian , Buschow René , Rose Alina , Wu Hua-Jun , Mackowiak Sebastian , Braendl Bjoern , Giesselmann Pay , Tornisiello Rosaria , Parsi Krishna Mohan , Huey Jack , Mielke Thorsten , Meierhofer David , Maehr René , Hnisz Denes , Michor Franziska , Rinn John L. , Meissner Alexander
Published: September 2022

Long non-coding RNAs (lncRNAs) have emerged as fundamental regulators in various biological processes, including embryonic development and cellular differentiation. Despite much progress over the past decade, the genome-wide annotation of lncRNAs remains incomplete and many known non-coding loci are still poorly characterized. Here, we report the discovery of a previously not annotated lncRNA that is transcribed upstream of the SOX17 gene and located within the same topologically associating domain. We termed it LNCSOX17 and show that it is induced following SOX17 activation but its expression is more tightly restricted to early definitive endoderm. Loss of LNCSOX17 affects crucial functions independent of SOX17 and leads to an aberrant endodermal transcriptome, signaling pathway deregulation and epithelial to mesenchymal transition defects. Consequently, cells lacking the lncRNA cannot further differentiate into more mature endodermal cell types. We identified and characterized LNCSOX17 as an essential new actor in early human endoderm, thereby further expanding the list of functionally important non-coding regulators.
Multi-omics analysis of mouse fecal microbiome reveals supplier-dependent functional differences and novel metagenome-assembled genomes
Authors: McAdams Zachary L , Busi Susheel Bhanu , Gustafson Kevin L , Bivens Nathan , Franklin Craig L , Wilmes Paul , Ericsson Aaron C
Published: September 2022

Host genetics, sex, and other within-source factors have been associated with characteristic effects on the fecal microbiome in mice, however, the commercial source of mice remains the dominant factor. Increasing evidence indicates that supplier-specific microbiomes in particular confer differences in disease susceptibility in models of inflammatory conditions, as well as baseline behavior and body morphology. However, current knowledge regarding the compositional differences between suppliers is based on 16S rRNA amplicon sequencing data, and functional differences between these communities remain poorly defined. Here, we applied a meta-omic (metagenomic and metatranscriptomic) approach to biomolecules (DNA/RNA) extracted from murine fecal samples representative of two large U.S. suppliers of research mice, which differ in composition, and influence baseline physiology and behavior as well as disease severity in mouse models of intestinal disease. We reconstructed high-quality metagenome-assembled genomes (MAGs), frequently containing genomic content unique to each supplier. These differences were observed both within pangenomes of dominant taxa as well as the epibiontSaccharimonadaceae. Additionally, transcriptional activity and pathway analyses revealed key functional differences between the metagenomes associated with each supplier, including differences in carbohydrate enzyme activity and dissimilatory sulfate reduction by sulfate-reducing bacteria (SRB). These data provide a detailed characterization of the baseline differences in the fecal metagenome of laboratory mice from two U.S. commercial suppliers suggesting that these functional differences are influenced by differences in the initial inoculum of colony founders, as well as additional taxa gained during growth of the production colony.
Redefining hypo- and hyper-responding phenotypes of CFTR mutants for understanding and therapy
Authors: Hillenaar Tamara , Beekman Jeffrey , van der Sluijs Peter , Braakman Ineke
Published: September 2022

Mutations in CFTR cause misfolding and decreased or absent ion-channel function, resulting in the disease Cystic Fibrosis. Fortunately, a triple-modulator combination therapy (Trikafta) has been FDA approved for 178 mutations, including all patients who have F508del on one allele. That so many CFTR mutants respond well to modulators developed for a single mutation is due to the nature of the folding process of this multidomain protein. We have addressed the question ‘What characterizes the exceptions: the mutants that functionally respond either not or extremely well’.

A functional response is the product of the number of CFTR molecules on the cell surface, open probability, and conductivity of the CFTR chloride channel. By combining biosynthetic radiolabeling with protease-susceptibility assays, we have followed CF-causing mutants during early and late stages of folding in presence and absence of modulators. Most CFTR mutants showed typical biochemical responses for each modulator, such as a TMD1 conformational change or an increase of (cell-surface) stability, regardless of a functional response. These modulators thus should still be considered for hypo-responder genotypes. Understanding both biochemical and functional phenotypes of outlier mutations will boost our insights into CFTR folding and misfolding, and lead to improved therapeutic strategies.
Increasing proteome depth while maintaining quantitative precision in short gradient data-independent acquisition proteomics
Authors: Doellinger Joerg , Blumenscheit Christian , Schneider Andy , Lasch Peter
Published: September 2022

The combination of short liquid chromatography (LC) gradients and data independent acquisition (DIA) by mass spectrometry (MS) has proven its huge potential for high-throughput proteomics. This methodology benefits from the speed of the latest generation of mass spectrometers, which enable short MS cycle times needed to provide sufficient sampling of sharp LC peaks. However, the optimization of isolation window schemes resulting in a certain number of data points per peak (DPPP) is understudied, although it is one of the most important parameters for the outcome of this methodology. In this study, we show that substantially reducing the number of DPPP for short gradient DIA massively increases protein identifications while maintaining quantitative precision. A deeper analysis of the underlying effects shows that a reduction of DPPP increases the selectivity of the data analysis, allowing fragment ions to be tracked over a longer period of the LC gradient. This in turn increases the number of precursors identified per protein, keeping the number of data points per protein nearly constant even at long cycle times. When proteins are inferred from its precursors, quantitative precision is maintained at low DPPP while greatly increasing proteomic depth. This strategy enabled us quantifying 6018 HeLa proteins (> 80,000 precursor identifications) with coefficients of variation below 20% in 30 min using a Q Exactive Orbitrap mass spectrometer, which corresponds to a throughput of 29 samples per day. This indicates that the potential of high-throughput DIA-MS has not been fully exploited yet.
The mediodorsal thalamus supports adaptive responding based on stimulus-outcome associations
Authors: Morceau Sarah , Faugère Angélique , Coutureau Etienne , Wolff Mathieu
Published: September 2022

The ability to engage into flexible behaviors is crucial in dynamic environments. We recently showed that in addition to the well described role of the orbitofrontal cortex (OFC), its thalamic input from the submedius thalamic nucleus (Sub) also contributes to adaptive responding during Pavlovian degradation. In the present study, we examined the role of the mediodorsal thalamus (MD) which is the other main thalamic input to the OFC. To this end, we assessed the effect of both pre- and post-training MD lesions in rats performing a Pavlovian contingency degradation task. Pre-training lesions mildly impeded the establishment of stimulus-outcome associations during the initial training of Pavlovian conditioning without interfering with Pavlovian degradation training when the sensory feedback provided by the outcome rewards were available to animals. However, we found that both pre- and post-training MD lesions produced a selective impairment during a test conducted under extinction conditions, during which only current mental representation could guide behavior. Altogether, these data suggest a role for the MD in the successful encoding and representation of Pavlovian associations.
A phase-separated biomolecular condensate nucleates polymerization of the tubulin homolog FtsZ to spatiotemporally regulate bacterial cell division
Authors: Ramm Beatrice , Schumacher Dominik , Harms Andrea , Heermann Tamara , Klos Philipp , Müller Franziska , Schwille Petra , Søgaard-Andersen Lotte
Published: September 2022

Cell division is spatiotemporally precisely regulated, but the underlying mechanisms are incompletely understood. In the social, predatory bacterium Myxococcus xanthus, the PomX/PomY/PomZ proteins form a single large megadalton-sized complex that directly positions and stimulates cytokinetic ring formation by the tubulin homolog FtsZ. Here, we studied the structure and mechanism of this complex in vitro and in vivo. We demonstrate that PomY forms liquid-like biomolecular condensates by phase separation, while PomX self-assembles into filaments generating a single large cellular structure. The PomX structure enriches PomY, thereby guaranteeing the formation of precisely one PomY condensate per cell through surface-assisted condensation. In vitro, PomY condensates selectively enrich FtsZ and nucleate GTP-dependent FtsZ polymerization, suggesting a novel cell division site positioning mechanism in which the single PomY condensate enriches FtsZ to guide FtsZ-ring formation and division. PomY-nucleated FtsZ polymerization shares features with microtubule nucleation by biomolecular condensates in eukaryotes, supporting this mechanism’s ancient origin.
Balanced SET levels favor the correct enhancer repertoire during cell fate acquisition
Authors: Mattia Zaghi , Banfi Federica , Massimino Luca , Volpin Monica , Bellini Edoardo , Brusco Simone , Merelli Ivan , Barone Cristiana , Bruni Michela , Bossini Linda , Lamparelli Luigi Antonio , Pintado Laura , D’Aliberti Deborah , Spinelli Silvia , Mologni Luca , Colasante Gaia , Ungaro Federica , Cioni Jean-Michel , Azzoni Emanuele , Piazza Rocco , Montini Eugenio , Broccoli Vania , Sessa Alessandro
Published: September 2022

Within the chromatin, distal elements interact with promoters to regulate specific transcriptional programs. Histone acetylation, interfering with the net charges of the nucleosomes, is a key player in this regulation. Here, we report that the onco-protein SET is a critical determinant for the levels of histone acetylation within enhancers. We disclose that conditions in which SET is accumulated, including the severe Schinzel-Giedion Syndrome (SGS), are characterized by a failure in the usage of the distal regulatory regions typically employed during fate commitment. This is accompanied by the usage of alternative enhancers leading to a massive rewiring of the distal control of the gene transcription. This represents a (mal)adaptive mechanism that, on one side, allows to achieve a certain degree of differentiation, while on the other affects the fine and corrected maturation of the cells. Thus, we propose the differential in cis-regulation as a contributing factor to the pathological basis of the SET-related disorders in humans, including SGS, neurodevelopmental disorders, myeloproliferative diseases, and cancer.
Structural basis for mTORC1-dependent regulation of the lysosomal and autophagic transcription factor TFEB
Authors: Cui Zhicheng , Napolitano Gennaro , de Araujo Mariana E. G. , Esposito Alessandra , Monfregola Jlenia , Huber Lukas A. , Ballabio Andrea , Hurley James H.
Published: September 2022

The transcription factor TFEB is a master regulator of lysosomal biogenesis and autophagy. The phosphorylation of TFEB by the mechanistic target of rapamycin complex 1 (mTORC1) is unique in its mTORC1 substrate recruitment mechanism, which is strictly dependent on the amino-acid-mediated activation of the RagC GAP FLCN. TFEB lacks the TOR signaling (TOS) motif responsible for the recruitment of other mTORC1 substrates. We used cryo-electron microscopy (cryo-EM) to determine the structure of TFEB as presented to mTORC1 for phosphorylation. Two full Rag-Ragulator complexes present each molecule of TFEB to the mTOR active site. One Rag-Ragulator complex is bound to Raptor in the canonical mode seen previously in the absence of TFEB. A second Rag-Ragulator complex (non-canonical) docks onto the first via a RagC GDP-dependent contact with the second Ragulator complex. The non-canonical Rag dimer binds the first helix of TFEB in a RagCGDP-dependent aspartate clamp in the cleft between the Rag G domains. Mutation of the clamp drives TFEB constitutively into the nucleus whilst having no effect on mTORC1 localization. The remainder of the 108-amino acid TFEB docking domain winds around Raptor and then back to RagA. This structure presents the phosphorylatable Ser residues of TFEB to the mTORC1 active site in a suitable geometry for their phosphorylation. The double use of RagC GDP contacts in both Rag dimers explains the strong dependence of TFEB phosphorylation on FLCN and the RagC GDP state.
Membrane potential dynamics of excitatory and inhibitory neurons in mouse barrel cortex during active whisker sensing
Authors: Kiritani Taro , Pala Aurélie , Gasselin Célia , Crochet Sylvain , Petersen Carl C.H.
Published: September 2022

Neocortical neurons can increasingly be divided into well-defined classes, but their activity patterns during quantified behavior remain to be fully determined. Here, we obtained membrane potential recordings from various classes of excitatory and inhibitory neurons located across different cortical depths in the primary whisker somatosensory barrel cortex of awake head-restrained mice during quiet wakefulness, free whisking and active touch. Excitatory neurons, especially those located superficially, were hyperpolarized with low action potential firing rates relative to inhibitory neurons. Parvalbumin-expressing inhibitory neurons on average fired at the highest rates, responding strongly and rapidly to whisker touch. Vasoactive intestinal peptide-expressing inhibitory neurons were excited during whisking, but responded to active touch only after a delay. Somatostatin-expressing inhibitory neurons had the smallest membrane potential fluctuations and exhibited hyperpolarising responses at whisking onset for superficial, but not deep, neurons. Interestingly, rapid repetitive whisker touch evoked excitatory responses in somatostatin-expressing inhibitory neurons, but not when the intercontact interval was long. Our analyses suggest that distinct genetically-defined classes of neurons at different subpial depths have differential activity patterns depending upon behavioral state providing an important basis for constraining future computational models of neocortical function.
A scalable, Rotating Disc Bioelectrochemical Reactor (RDBER) suitable for the cultivation of both cathodic and anodic biofilms
Authors: Hackbarth Max , Gescher Johannes , Horn Harald , Reiner Johannes Eberhard
Published: September 2022

This study discusses the construction and operation of a membrane-less bioelectrochemical reactor that employs rotating working electrodes with a surface area of up to 1 m2. As a proof-of-principle for an aerobic microbial electrosynthesis process,Kyrpidia spormanniiwas cultivated in the reactor. Optical coherence tomography was used to examine the spatial distribution of the cathodic biofilm. After 24 days 87% of the cathode surface was covered with biofilm that was characterized by a radial increase in its biovolume towards the circumcenter of the electrodes reaching up to 92.13 μm3μm-2. To demonstrate the versatility of the system, we further operated the reactor as a microbial electrolysis cell employing a co-culture ofShewanella oneidensisandGeobacter sulfurreducens. Anodic current densities of up to 130 μA cm-2were measured during these batch experiments. This resulted in a maximum production rate of 0.43 liters of pure hydrogen per liter reactor volume and day.

Graphical Abstract

Highlights

Construction of a 10 L membrane-less, pressurizable bioelectrochemical reactor

Rotating working electrodes with up to 1 m2electrode surface

Electroautotrophic cultivation and quantification ofK. spormanniibiofilms

Initial cell density crucial for successfulK. spormanniibiofilm formation

Anodic operation as MEC withShewanella/Geobactercoculture
Cell adhesion and spreading on fluid membranes through microtubules-dependent mechanotransduction
Authors: Mikhajlov Oleg , Adar Ram M. , Tătulea-Codrean Maria , Macé Anne-Sophie , Manzi John , Tabarin Fanny , Battistella Aude , di Federico Fahima , Joanny Jean-François , van Nhieu Guy Tran , Bassereau Patricia
Published: September 2022

During cell adhesion, integrins form clusters that transmit mechanical forces to the substrate (mechanotransduction) and regulate biochemical signaling depending on substrate stiffness. Studies on mechanotransduction significantly advanced our understanding of cell adhesion and were mostly performed on rigid substrates. In contrast to rigid substrates, integrins’ ligands on fluid supported lipid bilayers (SLBs) are mobile and adhesive complexes cannot serve as anchoring points promoting cell spreading. Here, we demonstrate that cells spread on SLBs coated with Invasin, a high-affinity integrin ligand. We show that in contrast to SLBs functionalized with RGD peptides, integrin clusters grow in size and complexity on Invasin-SLBs to a similar extent as on glass. While actomyosin contraction dominates adhesion maturation on stiff substrates, we find that integrin mechanotransduction and cell spreading on fluid SLBs rely on dynein pulling forces along microtubules perpendicular to membranes and microtubules pushing on adhesive complexes, respectively. These forces that may also occur on non-deformable surfaces are revealed in fluid substrate set ups. Our findings, supported by a theoretical model, demonstrate a new mechanical role for microtubules in integrin clustering.
ARHGAP18-ezrin functions as an autoregulatory module for RhoA in the assembly of distinct actin-based structures
Authors: Lombardo Andrew T. , Mitchell Cameron A. R. , Zaman Riasat , McDermitt David J. , Bretscher Anthony
Published: September 2022

The location of different actin-based structures is largely regulated by Rho GTPases through specific effectors. We use the apical aspect of epithelial cells as a model system to investigate how RhoA is locally regulated to contribute to two distinct adjacent actin-based structures. Assembly of the non-muscle myosin-2 filaments in the terminal web is dependent on RhoA activity, and assembly of the microvilli also requires active RhoA for phosphorylation and activation of ezrin. We show the RhoGAP, ARHGAP18, is localized by binding active microvillar ezrin, and this interaction enhances ARHGAP18’s RhoGAP activity. We present a model where ezrin-ARHGAP18 acts as a negative autoregulatory module to locally reduce RhoA activity in microvilli. Consistent with this model, loss of ARHGAP18 results in disruption of the distinction between microvilli and the terminal web including aberrant assembly of myosin-2 filaments forming inside microvilli. Thus, ARHGAP18, through its recruitment and activation by ezrin, fine-tunes the local level of RhoA to allow for the appropriate distribution of actin-based structures between the microvilli and terminal web. As RhoGAPs vastly out-number Rho GTPases, this may represent a general mechanism whereby individual Rho effectors drive specific actin-based structures.
Activity-dependent post-translational regulation of palmitoylating and de-palmitoylating enzymes in the hippocampus
Authors: Abazari Danya , Wild Angela R , Qiu Tian , Dickinson Bryan C. , Bamji Shernaz X
Published: September 2022

Activity-induced changes in protein palmitoylation can regulate the plasticity of synaptic connections, critically impacting learning and memory. Palmitoylation is a reversible post-translational modification regulated by both palmitoyl-acyl transferases that mediate palmitoylation and palmitoyl thioesterases that depalmitoylate proteins. However, it is not clear how fluctuations in synaptic activity can mediate the dynamic palmitoylation of neuronal proteins. Using primary hippocampal cultures, we demonstrate that synaptic activity does not impact the transcription of palmitoylating / depalmitoylating enzymes, changes in thioesterase activity, nor post-translational modification of the depalmitoylating enzymes, ABHD17 and APT2. In contrast, synaptic activity does mediate post-translational modification of the palmitoylating enzymes ZDHHC2, ZDHHC5, and ZDHHC9 (but not ZDHHC8) to influence protein-protein interaction, enzyme stability and enzyme function. Post-translational modifications of ZDHHC enzymes were also observed in the hippocampus following fear conditioning. Together, our findings demonstrate that signaling events activated by synaptic activity largely impact activity of the ZDHHC family of palmitoyl-acyl transferases with less influence on the activity of palmitoyl thioesterases.
The different effect of pharmacological or low-doses of IFN-γ in endothelial cells are mediated by different intracellular signaling pathways
Authors: Cazzaniga Alessandra , Miranda Vincenzo , Castiglioni Sara , Maier Jeanette A.M.
Published: September 2022

Interferon (IFN)-γ is a proinflammatory cytokine with a crucial role in intercellular communication during innate and acquired immune responses. IFN-γ interacts with many cell types, among which endothelial cells. Here, we show that pharmacological and low-dose kinetically activated (SKA) IFN-γ exert different effects on endothelial cells by activating different signal transduction pathways. Pharmacological concentrations of IFN-γ activate JAK/STAT pathway, inducing the overexpression of the CDKN1A p21, which in turn inhibits cell growth. Conversely, low-dose SKA IFN-γ does not activate the canonical JAK/STAT pathway but induces the phosphorylation of ERK. ERK activation is responsible for the induction of endothelial cell migration. Interestingly, ERK activation occurs only in the presence of kinetically activate low-dose IFN-γ, underlying the importance of mechanical forces to potentiate IFN-γ activity.
Synthesis and crystal structure of 3-phenyl-1,4,2-dithiazole-5-thione
Authors: Schriver Melbourne J. , George Tanner , Masuda Jason D.
Published: September 2022

In the title compound, C8H5NS3, the dihedral angle between the heterocyclic ring and the phenyl ring is 2.62 (5)°. In the extended structure, aromatic π–π stacking between the 1,4,2-dithiazole-5-thione moiety and the phenyl ring is observed [centroid–centroid distances = 3.717 (6) and 3.712 (6) Å]. The almost planar molecules arrange themselves in parallel chains of head-to-tail molecules oriented by a network of weak C—H...S contacts close to the sum of their van der Waals radii within the chains. All the hydrogen atoms participate in hydrogen-bonding interactions with the sulfur and nitrogen atoms of adjacent molecules. C=S...S contacts between the chains that are significantly shorter than the sum of their van der Waals radii also impact the overall packing.
3-(2,3-Dimethoxyphenyl)-2,3-dihydro-1H-benzo[f]chromen-1-one
Authors: Sung Jiha
Published: September 2022

In the title compound, C21H18O4, the central pyran ring is in an envelope conformation and the dihedral angle between the benzene ring and naphthalene ring system is 88.31 (1)°. The methoxy groups at the ortho and meta positions of the benzene ring are tilted to the ring with C—C—O—C torsion angles of 105.9 (4) and 9.5 (5)°, respectively. In the crystal, pairwise C—H...O hydrogen bonds form R
2
2(14) inversion dimers, which are linked by another pair of C—H...O hydrogen bonds to form [210] chains in the crystal.
Further evidence on the effect of financial performance and governance on the Islamic banks' disclosure
Authors: Ben Abdallah Mariem , Bahloul Slah
Published: September 2022

Purpose

The purpose of this study is to investigate the effect of financial performance (FP) and governance on the accounting and auditing organization for Islamic financial institutions (AAOIFI) disclosure for the Islamic banks.

Design/methodology/approach

The authors used the generalized least squares (GLS) estimation for 47 MENASA (Middle East, North Africa and Southeast Asia) Islamic banks (IBs) between 2012 and 2019. In this regression, disclosure is the endogenous variable. The performance and governance measures are the explanatory parameters. The authors use bank's size, leverage and age for control parameters. The robustness of results is verified via generalized method of moments (GMM) estimation method.

Findings

The findings indicate that performance measurement has weak effects on AAOIFI disclosure. Only the net interest margin (NIM) measure has a significant positive impact. The return of assets (ROA) and the return on equity (ROE) have a significant negative impact. Furthermore, all Shariah Governance measures have significant effects. Finally, the findings of this study support the governance's positive contribution to the disclosure in IBs.

Practical implications

Through including the whole issues allied to AAOIFI and their impacts on the banks' value, this study provides a significant summary for IBs, policymakers, regulators, AAOIFI and connected authorities across countries. In addition, the findings linked powers between jurisdictions with recommendations on growing the present AAOIFI practices.

Originality/value

This paper offers an original contribution to the accounting professionals and stakeholders who investigate the relationship between disclosure, performance and governance. It is considered as a basis for future studies in the simultaneous relation between these variables. It is crucial for accounting professionals, researchers and stakeholders interesting in the financial disclosure (FD) in IBs.
Government subsidization and corporate product strategies: evidence from Chinese exporters
Authors: Lu Xiaodong , Liu Jingjun , Zhang Janus Jian
Published: September 2022

Purpose

This study aims to take advantage of exporters’ product codes and examine the effects of government subsidization on corporate product strategies by focusing on the dimension of product differentiation.

Design/methodology/approach

This study uses harmonized system (HS) product codes to construct a novel measure of product differentiation among a sample of Chinese exporters during 2000–2012. It uses propensity score matching to construct a comparable sample of control firms for exporters receiving government subsidies, and then a difference-in-differences (DID) analysis is conducted.

Findings

This study finds that product differentiation decreases immediately upon receiving a government subsidy. This finding suggests that in an emerging market, firms use their subsidy to imitate competitors rather than increase innovation. Further analyses show that this effect is concentrated among wholly foreign-owned enterprises and firms that focus on general trade rather than processing trade. In addition, the authors find some evidence that government subsidization leads to an increase in the number of product lines and decreases in domestic value added and export product quality.

Originality/value

This study constructs a novel measure of product differentiation for a large sample of Chinese exporters and provides insights that government subsidization can affect corporate product strategies.
Modeling influence mechanism of factors on corporate social responsibility implementation: evidence from Chinese construction firms
Authors: Zhang Qian , Oo Bee Lan , Lim Benson Teck-Heng
Published: September 2022

Purpose

The interest in corporate social responsibility (CSR) has become burgeoning in the construction industry as firms are under constant pressure from socially conscious stakeholders to demonstrate their efforts to address various CSR issues. This study aims to unveil the key practices and impact factors (KPIFs) of CSR implementation in construction firms and the interrelationships among different key impact factors toward attaining CSR practices.

Design/methodology/approach

Mobilizing the integrated institutional, stakeholder and self-determination theories, a theoretical framework was first developed to elaborate the potential inter-relationships among the key impact factors toward CSR implementation. Data were collected from extra-grade contractors through an online questionnaire survey and was then analyzed by the partial least square structural equation modeling method.

Findings

The results show that construction firms' CSR practices could be classified into eight distinct key dimensions, e.g. shareholders' interests, government commitment and environment preservation. It is found that three groups of key impact factors – external institutional factors (especially coercive-normative factors), intrinsic factors (especially strategic business direction and organizational culture) and identified factors (i.e. the perceived importance of CSR practices) – have statistically significant positive impacts on most key dimensions of CSR practices.

Practical implications

The research findings have implications for top management to better understand CSR implementation, thereby helping them secure legitimacy to survive and advance in the competitive construction businesses.

Originality/value

The findings contribute to the theoretical body of knowledge in CSR by modeling and empirically demonstrating the influence mechanism of CSR implementation in construction within an integrated model.
Pre‐service teachers' attitudes towards inclusion in Finland
Authors: Takala Marjatta , Sirkko Riikka
Published: September 2022

The attitudes towards inclusion and the terms used related to special needs by pre‐service teachers in three Finnish universities were studied. Inclusion is the main educational policy in Finland, and special solutions are avoided when possible. With a questionnaire and a brief survey, data from 488 pre‐service teachers (PSTs) were collected and analysed qualitatively and quantitatively. Results indicated that their attitudes towards inclusion were quite negative. Most of the positive attitudes, which were below the mean of the scale, were held by PSTs with special education as their major or as part of their studies, along with early education PSTs. The terms used for special needs were partly traditional, following the medical model of disability, but many students also referred to the structure of the support. The reasons for the negative attitudes and changes in the traditional names of special needs are also discussed.
Pushing the boundaries: Power, privilege and the problem with inclusion
Authors: Barton Nimisha
Published: September 2022

Through a blend of personal narrative and a survey of recent historical scholarship on gender, race and reproduction, this article asks readers to consider how our own proximity to power, privilege and oppression shapes the ways we approach the study of history. It argues that age‐old disciplinary dogmas exist for a reason and they can unintentionally limit our imaginations. It also suggests how those of us for whom the academy was never intended can help push those scholarly boundaries and perhaps even breathe new life into a disappearing discipline.
Fumarate mitigates disruption induced by fenpropathrin in the silkworm Bombyx mori (Lepidoptera): A metabolomics study
Authors: Wang Xue‐Yang , Zhao Zi‐Qin , Song Cheng‐Xian , Su Zhi‐Hao , Li Mu‐Wang , Wu Yang‐Chun , Jin Byung Rae , Deng Ming‐Jie
Published: September 2022

The silkworm Bombyx mori L. is a model organism of the order Lepidoptera. Understanding the mechanism of pesticide resistance in silkworms is valuable for Lepidopteran pest control. In this study, comparative metabolomics was used to analyze the metabolites of 2 silkworm strains with different pesticide resistance levels at 6, 12, and 24 h after feeding with fenpropathrin. Twenty‐six of 27 metabolites showed significant differences after fenpropathrin treatment and were classified into 6 metabolic pathways: glycerophospholipid metabolism, sulfur metabolism, glycolysis, amino acid metabolism, the urea cycle, and the tricarboxylic acid (TCA) cycle. After analyzing the percentage changes in the metabolic pathways at the 3 time points, sulfur metabolism, glycolysis, and the TCA cycle showed significant responses to fenpropathrin. Confirmatory experiments were performed by feeding silkworms with key metabolites of the 3 pathways. The combination of iron(II) fumarate + folic acid (IF‐FA) enhanced fenpropathrin resistance in silkworms 6.38 fold, indicating that the TCA cycle is the core pathway associated with resistance. Furthermore, the disruption of several energy‐related metabolic pathways caused by fenpropathrin was shown to be recovered by IF‐FA in vitro. Therefore, IF‐FA may have a role in boosting silkworm pesticide resistance by modulating the equilibrium between the TCA cycle and its related metabolic pathways.