bluuebunny/crossref_metadata_2025 huggingface dataset:
USP20 deubiquitinates and stabilizes the ER-phagy receptor FAM134B to drive ER-phagy
Authors: Man Zhang , Wang Zhangshun , Zhao Qing , Yang Qian , Yang Cuiwei , Liu Yanfen
Published: July 2023

The endoplasmic reticulum (ER) serves as a hub for various essential cellular processes, and maintaining ER homeostasis is essential for cell function. ER-phagy is a selective process that removes impaired ER subdomains through autophagosomes and lysosomal degradation. While the involvement of ubiquitination in autophagy regulation is well-established, its role in ER-phagy remains unclear. In our study, we screened deubiquitinating enzymes involved in ER-phagy and identified USP20 (ubiquitin specific peptidase 20) as a key regulator of ER-phagy under stress conditions. USP20 specifically cleaves K63– and K48-linked ubiquitin chains on the ER-phagy receptor FAM134B/RETREG1 (reticulophagy regulator 1), thereby stabilizing the substrate and promoting ER-phagy. Remarkably, despite lacking a transmembrane domain, USP20 is recruited to the ER through its interaction with VAPs (vesicle-associated membrane proteins). VAPs facilitate the recruitment of early autophagy proteins, including WIPI2, to specific ER subdomains, where USP20 and FAM134B are enriched. This recruitment of WIPI2 and other proteins plays a crucial role in facilitating FAM134B-mediated ER-phagy in response to cellular stress. Our findings highlight the critical role of USP20 in maintaining ER homeostasis by deubiquitinating and stabilizing FAM134B at distinct ER subdomains, where USP20 further recruits VAPs and promotes efficient ER-phagy.
Systematic exploration of bacterial form I rubisco maximal carboxylation rates
Authors: de Pins Benoit , Greenspoon Lior , Bar-On Yinon M. , Shamshoum Melina , Ben-Nissan Roee , Milshtein Eliya , Davidi Dan , Sharon Itai , Mueller-Cajar Oliver , Noor Elad , Milo Ron
Published: July 2023

Autotrophy is the basis for complex life on Earth. Central to this process is rubisco - the enzyme that catalyzes almost all carbon fixation on the planet. Yet, with only a small fraction of rubisco diversity kinetically characterized so far, the underlying biological factors driving the evolution of fast rubiscos in nature remain unclear. We conducted a high-throughput kinetic characterization of over 100 bacterial form I rubiscos, the most ubiquitous group of rubisco sequences in nature, to uncover the determinants of rubisco’s carboxylation velocity. We show that the presence of a carboxysome CO2concentrating mechanism correlates with faster rubiscos with a median 5-fold higher rate. In contrast to prior studies, we find that rubiscos originating from α-cyanobacteria exhibit the highest carboxylation rates among form I enzymes (≈10 s-1median versus <7 s-1in other groups). Our study systematically reveals biological and environmental properties associated with kinetic variation across rubiscos from nature.
Evolution end classification oftfdgene clusters mediating bacterial degradation of 2,4-dichlorophenoxyacetic acid (2,4-D)
Authors: Iasakov Timur
Published: July 2023

Thetfd(tfdIandtfdII) are gene clusters originally discovered in plasmid pJP4 which is involved in the bacterial degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) via the ortho-cleavage pathway of chlorinated catechols. They share this activity, with respect to substituted catechols, with clusterstcbandclc. Although great efforts have been devoted over nearly forty years to exploring the structural diversity of these clusters, their evolution has been poorly resolved to date, and their classification is clearly obsolete. Employing comparative genomic and phylogenetic approaches revealed that alltfdclusters can be classified as one of four different types. The following four-type classification and new nomenclature are proposed:tfdI,tfdII,tfdIIIandtfdIV(A,B,C). Horizontal gene transfer betweenBurkholderialesandSphingomonadalesprovided phenomenal linkage betweentfdI,tfdII,tfdIIIandtfdIVtype clusters and their mosaic nature. It is hypothesized that the evolution oftfdgene clusters proceeded within first (tcb,clcandtfdI), second (tfdIIandtfdIII) and third (tfdIV(A,B,C)) evolutionary lineages in each of which the genes were clustered in specific combinations. Their clusterization has been discussed through the prism of hot spots and driving forces of various models, theories, and hypotheses of cluster and operon formation. Two hypotheses about series of gene deletions and displacements have also been proposed to explain the structural variations across members of clusterstfdIIandtfdIII, respectively. Taking everything into account, these findings reconstructing the phylogeny oftfdclusters, have delineated their evolutionary trajectories, and allowed the contribution of various evolutionary processes to be assessed.
The nuclei of human adult stem cells can move within the cell and generate cellular protrusions to contact other cells
Authors: Bueno Carlos , García-Bernal David , Martínez Salvador , Blanquer Miguel , Moraleda José M.
Published: July 2023

Despite a considerable interest in understanding the mechanisms regulating nucleus structure, chromatin organization and nuclear positioning over decades, the exact significance of the variety of morphologies and positioning that cell nuclei can adopt and their relationship in cellular function is still far from being clearly understood. In this study, we examined the functional significance of the variety of morphologies and positioning that cell nuclei of human bone marrow-derived mesenchymal stem cells can adopt during neural-like differentiation. Here, we show that after neural induction, human bone marrow-derived mesenchymal stem cells enter an intermediate cellular state in which the nuclei are observed to be able to move within the cells, switching shapes and positioning and even generating cellular protrusions as they attempt to contact the cells around them. These findings suggest that changes in nuclear positioning are due to the fact that human cell nuclei somehow sensing their environment.
RNA-mediated Allosteric Activation in CRISPR-Cas13a
Authors: Sinha Souvik , Molina Vargas Adrian M. , Arantes Pablo R. , Patel Amun , O’Connell Mitchell R. , Palermo Giulia
Published: July 2023

Cas13a is a recent addition to the CRISPR-Cas toolkit that exclusively targets RNA, which makes it a promising tool for RNA detection. The protein uses a CRISPR RNA (crRNA) to target RNA sequences, which are cleaved by a composite active site formed by two ‘Higher Eukaryotes and Prokaryotes Nucleotide’ (HEPN) catalytic domains. In this system, an intriguing form of allosteric communication controls RNA cleavage activity, yet its molecular details are unknown. Here, multiple-microsecond molecular dynamics simulations are combined with graph theory and RNA cleavage assays to decipher this activation mechanism. We show that the binding of a target RNA acts as an allosteric effector of the spatially distant HEPN catalytic cleft, by amplifying the allosteric signals over the dynamical noise, that passes through the buried HEPN interface. Critical residues in this region – N378, R973, and R377 – rearrange their interactions upon target RNA binding, and alter allosteric signalling. Alanine mutation of these residues is experimentally shown to select target RNA over an extended complementary sequence beyond guide-target duplex, for RNA cleavage. Altogether, our findings offer a fundamental understanding of the Cas13a mechanism of action and pave new avenues for the development of more selective RNA-based cleavage and detection tools.
PROTECTIVE EFFECTS OF TRITERPENOID BETULIN ON TYPE 2 DIABETES MELLITUS IN RATS
Authors: Shlyahtun A. H. , Maksimchik Yu. Z. , Zakrzeska A. , Sutsko I. P. , Raduta A. F. , Buksha E. V. , Bogdevich E. V. , Kitlas P. , Tomulewicz M.
Published: July 2023

Type 2 diabetes mellitus (T2DM) is a complex chronic metabolic disease characterized by long-term hyperglycemia, which is, in turn, resulted from the impaired insulin signaling caused by a combination of insulin resistance or inadequate insulin production. Prevalence and incidence of T2DM are increasing dramatically across the world, and it is accompanied with severe complications and premature mortality of patients with diabetes. Given the fact that synthetic drugs have disadvantages in view of the side effects, the implementation of naturally occurring compounds for diabetes treatment may be a promising alternative. Betulin is a naturally occurring triterpenoid which has been shown to possess the ability of altering body lipids and exert hypoglycemic and hepatoprotective effects. It is suggested that the application of betulin in T2DM may have a favorable effect to ease the severity of diabetic complications. Thus, the aim of the present study was to assess biological effects of betulin in T2DM conditions.

Diabetes-induced rats were administered with two different doses of betulin for 28 consecutive days. It was shown that long-term administration of betulin at the doses of 50 and 100 mg/kg/day to the rats prevented diabetes-associated changes in a body weight of the animals, significantly reversed insulin resistance and abolished the impairment of glucose metabolism. It was accompanied with the dose-dependent normalization of serum lipid contents. Histopathological changes and structural abnormalities in the liver of diabetics were restored by the administration of betulin. Also, betulin was able to restrain systemic inflammation detected in diabetic animals according to the altered levels of serum TNFα. Thus, the results obtained in the current study were found to be in agreement with earlier findings on beneficial effects of betulin in conditions pathogenetically close to T2DM. We hypothesized that the ability of betulin to restrain systemic inflammation and to normalize the lipid metabolism can explain improved insulin resistance and glycemic control and it can provide a possible mechanism for the beneficial antidiabetic effects of betulin.
Pupil-size sensitivity to listening demand depends on motivational state
Authors: Kraus Frauke , Obleser Jonas , Herrmann Björn
Published: July 2023

Motivation plays a role when a listener needs to understand speech under acoustically demanding conditions. Previous work has demonstrated pupil-linked arousal being sensitive to both listening demands and motivational state during listening. It is less clear how motivational state affects the temporal evolution of the pupil size and its relation to subsequent behavior. We used an auditory gap-detection task (N=33) to study the joint impact of listening demand and motivational state on the pupil-size response and examine its temporal evolution. Task difficulty and a listener’s motivational state were orthogonally manipulated through changes in gap duration and monetary-reward prospect. We show that participants’ performance decreased with task difficulty, but that reward prospect enhanced performance under hard listening conditions. Pupil size increased with both increased task difficulty and higher reward prospect, and this reward-prospect effect was largest under difficult listening conditions. Moreover, pupil-size time courses differed between detected and missed gaps, suggesting that the pupil response indicates upcoming behavior. Larger pre-gap pupil size was further associated with faster response times on a trial-by-trial within-participant level. Our results reiterate the utility of pupil size as an objective and temporally sensitive measure in audiology. However, such assessments of cognitive-resource recruitment need to consider the individual’s motivational state.

Significance statement

The literature is inconclusive to what degree pupil size may be representing the interaction of listening task demand and an individual’s motivational state. Using an auditory gap-detection task, we manipulated both the degree of listening demand and a person’s motivational state, and investigated the temporal evolution of the pupil-size response and its relation to behavior. We find that the pupil size represents the interaction of demand and motivational state. These results highlight the importance of considering a person’s motivational state when using pupil size as a clinical measure. Pupil size appears as a key tool when assessing the impact of motivational state on the recruiting of cognitive resources.
Functional and Structural Characterization of an IclR Family Transcription Factor for the Development of Dicarboxylic Acid Biosensors
Authors: Pham Chester , Nasr Mohamed , Skarina Tatiana , Leo Rosa Di , Kwan David H. , Martin Vincent J.J. , Stogios Peter J. , Mahadevan Radhakrishnan , Savchenko Alexei
Published: July 2023

Prokaryotic transcription factors (TFs) regulate gene expression in response to small molecules, thus representing promising candidates as versatile small molecule-detecting biosensors valuable for synthetic biology applications. The engineering of such biosensors requires thoroughin vitroandin vivocharacterization of TF ligand response as well as detailed molecular structure information. In this work we characterize the PcaR TF belonging to the IclR family. We presentin vitrofunctional analysis of PcaR’s ligand profile and construction of genetic circuits for the characterization of PcaR as anin vivobiosensor in the model eukaryoteSaccharomyces cerevisiae. We report the crystal structures of PcaR in theapostate and in complex with one of its ligands, succinate, which suggests the mechanism of dicarboxylic acid recognition by this TF. This work provides key structural and functional insights enabling the engineering of PcaR for dicarboxylic acid biosensors.

Graphical Abstract

Highlights

PcaR is an IclR family transcription regulator responsive to dicarboxylic acids

PcaR was established as anin vivobiosensor in yeast

Crystal structure of PcaR in theapoform was solved

Crystal structure with PcaR in complex with succinate was solved

Sequence alignments unveil ligand-binding positions in the IclR family
Mechano-induced homotypic patterned domain formation by monocytes
Authors: Du Wenxuan , Zhu Jingyi , Wu Yufei , Kiemen Ashley L. , Sun Sean X. , Wirtz Denis
Published: July 2023

Matrix stiffness and corresponding mechano-signaling play indispensable roles in cellular phenotypes and functions. How tissue stiffness influences the behavior of monocytes, a major circulating leukocyte of the innate system, and how it may promote the emergence of collective cell behavior is less understood. Here, using tunable collagen-coated hydrogels of physiological stiffness, we show that human primary monocytes undergo a dynamic local phase separation to form highly patterned multicellular multi-layered domains on soft matrix. Local activation of the β2 integrin initiates inter-cellular adhesion, while global soluble inhibitory factors maintain the steady-state domain pattern over days. Patterned domain formation generated by monocytes is unique among other key immune cells, including macrophages, B cells, T cells, and NK cells. While inhibiting their phagocytic capability, domain formation promotes monocytes’ survival. We develop a computational model based on the Cahn-Hilliard equation, which includes combined local activation and global inhibition mechanisms of intercellular adhesion suggested by our experiments, and provides experimentally validated predictions of the role of seeding density and both chemotactic and random cell migration on pattern formation.
Kremen1 regulates the regenerative capacity of support cells and mechanosensory hair cells in the zebrafish lateral line
Authors: Megerson Ellen , Kuehn Michael , Leifer Ben , Bell Jon , McGraw Hillary F.
Published: July 2023

Mechanosensory hair cells in the inner ear mediate the sensations of hearing and balance, and in a specialize lateral line sensory system of aquatic vertebrates, the sensation of water movement. In mammals, hair cells lack the ability of regenerate following damage, resulting in sensory deficits. In contrast, non-mammalian vertebrates, such zebrafish, can renew hair cells throughout the life of the animal. Wnt signaling is required for development of inner ear and lateral line hair cells and regulates regeneration. Kremen1 inhibits Wnt signaling and hair cell formation, though its role in regeneration has not been established. We use a zebrafishkremen1mutant line, to show that when Wnt signaling is overactivated in the lateral line, excessive regeneration occurs in the absence of increased proliferation, due to an increase in support cells. This contrasts with the previously described role of Wnt signaling during hair cell regeneration. This work will allow us to understand the biology of mechanosensory hair cells, and how regeneration might be promoted following damage.
Inducing a meditative state by artificial perturbations: A causal mechanistic understanding of brain dynamics underlying meditation
Authors: Dagnino Paulina Clara , Galadí Javier A. , Càmara Estela , Deco Gustavo , Escrichs Anira
Published: July 2023

Contemplative neuroscience has increasingly explored meditation using neuroimaging. However, the brain mechanisms underlying meditation remain elusive. Here, we implemented a causal mechanistic framework to explore the spatiotemporal dynamics of expert meditators during meditation and rest. We first applied a model-free approach by defining a probabilistic metastable substate (PMS) space for each state, consisting of different probabilities of occurrence from a repertoire of dynamic patterns. Different brain signatures were mainly found in the triple-network model (i.e., the executive control, salience, and default-mode networks). Moreover, we implemented a model-based approach by adjusting the PMS of the resting state to a whole-brain model, which enabled us to explorein silicoperturbations to transition to the meditation state. Consequently, we assessed the sensitivity of different brain areas regarding their perturbability and their mechanistic local-global effects. Using a synchronous protocol, we successfully transitioned from the resting state to the meditative state by shifting areas mainly from the somatomotor and dorsal attention networks. Overall, our work reveals distinct whole-brain dynamics in meditation compared to rest, and how the meditation state can be induced with localized artificial perturbations. It motivates future work regarding meditation as a practice in health and as a potential therapy for brain disorders.
A single-cell transcriptomic atlas reveals resident dendritic-like cells in the zebrafish brain parenchyma
Authors: Rovira Mireia , Ferrero Giuliano , Miserocchi Magali , Montanari Alice , Wittamer Valérie
Published: July 2023

Recent studies have highlighted the heterogeneity of the immune cell compartment within the steady-state murine and human CNS. However it is not known whether this diversity is conserved among non mammalian vertebrates, especially in the zebrafish, a model system with increasing translational value. Here, we reveal the complexity of the immune landscape of the adult zebrafish brain. Using single-cell transcriptomics, we characterized these different immune cell subpopulations, including cell types that have not been -or have been poorly-characterized in zebrafish so far. By histology, we found that, despite microglia being the main immune cell type in the parenchyma, the zebrafish brain is also populated by a distinct myeloid population that shares a gene signature with mammalian dendritic cells (DC). Notably, zebrafish DC-like cells rely onbatf3, a gene essential for the development of conventional DC1 in the mouse. Using specific fluorescent reporter lines that allowed us to reliably discriminate DC-like cells from microglia, we quantified brain myeloid cell defects in commonly usedirf8-/-,csf1ra-/-andcsf1rb-/-mutant fish, revealing previously unappreciated distinct microglia and DC-like phenotypes. Overall, our results suggest a conserved heterogeneity of brain immune cells across vertebrate evolution and also highlights zebrafish-specific brain immunity characteristics.
ChromaFold predicts the 3D contact map from single-cell chromatin accessibility
Authors: Gao Vianne R. , Yang Rui , Das Arnav , Luo Renhe , Luo Hanzhi , McNally Dylan R. , Karagiannidis Ioannis , Rivas Martin A. , Wang Zhong-Min , Barisic Darko , Karbalayghareh Alireza , Wong Wilfred , Zhan Yingqian A. , Chin Christopher R. , Noble William , Bilmes Jeff A. , Apostolou Effie , Kharas Michael G. , Béguelin Wendy , Viny Aaron D. , Huangfu Danwei , Rudensky Alexander Y. , Melnick Ari M. , Leslie Christina S.
Published: July 2023

The identification of cell-type-specific 3D chromatin interactions between regulatory elements can help to decipher gene regulation and to interpret the function of disease-associated non-coding variants. However, current chromosome conformation capture (3C) technologies are unable to resolve interactions at this resolution when only small numbers of cells are available as input. We therefore present ChromaFold, a deep learning model that predicts 3D contact maps and regulatory interactions from single-cell ATAC sequencing (scATAC-seq) data alone. ChromaFold uses pseudobulk chromatin accessibility, co-accessibility profiles across metacells, and predicted CTCF motif tracks as input features and employs a lightweight architecture to enable training on standard GPUs. Once trained on paired scATAC-seq and Hi-C data in human cell lines and tissues, ChromaFold can accurately predict both the 3D contact map and peak-level interactions across diverse human and mouse test cell types. In benchmarking against a recent deep learning method that uses bulk ATAC-seq, DNA sequence, and CTCF ChIP-seq to make cell-type-specific predictions, ChromaFold yields superior prediction performance when including CTCF ChIP-seq data as an input and comparable performance without. Finally, fine-tuning ChromaFold on paired scATAC-seq and Hi-C in a complex tissue enables deconvolution of chromatin interactions across cell subpopulations. ChromaFold thus achieves state-of-the-art prediction of 3D contact maps and regulatory interactions using scATAC-seq alone as input data, enabling accurate inference of cell-type-specific interactions in settings where 3C-based assays are infeasible.
Motor learning- and consolidation-related resting state fast and slow brain dynamics across wake and sleep
Authors: Roshchupkina Liliia , Wens Vincent , Coquelet Nicolas , Urbain Charline , de Tiege Xavier , Peigneux Philippe
Published: July 2023

Learning and consolidation of motor skills dynamically evolve both online during practice and offline after training. We investigated, using magnetoencephalography, the neural dynamics underpinning motor learning and its consolidation in relation to sleep during resting-state periods shortly after the end of learning (short-term boost window, within 30 min) and at more delayed time scales (silent 4h and next day 24h windows) with an intermediate nap or wakefulness after the boost window. Resting-state neural dynamics in brain networks were investigated at fast (sub-second) and slower (supra-second) timescales using Hidden Markov modelling (HMM) and resting-state functional connectivity (rsFC), respectively, as well as their relationship with the evolution of motor performance. HMM results show that fast dynamic activities in a Temporal/Sensorimotor state network predict individual motor performance achievements, suggesting a trait-like association between rapidly recurrent neural patterns and motor behaviour. Short, post-training re-exposure to the task modulated fast and slow network characteristics during the boost but not in the silent window. These short practice-related induction effects were observed again on the next day, to a reduced extent as compared to the boost window. Daytime naps did not significantly modulate memory consolidation both at behavioural and neural levels. These results emphasise the critical role of the transient boost window in motor learning and subsequent memory consolidation processes and provide further insights into the relationship between the multiscale neural dynamics of brain networks, motor learning, and consolidation.
Genetic context drives age-related disparities in synaptic maintenance and structure across cortical and hippocampal neuronal circuits
Authors: Heuer Sarah E. , Nickerson Emily W. , Howell Gareth R. , Bloss Erik B.
Published: July 2023

The disconnection of neuronal circuits through synaptic loss is presumed to be a major driver of age-related cognitive decline. Age-related cognitive decline is heterogeneous, yet whether genetic mechanisms differentiate successful from unsuccessful cognitive decline through synaptic structural mechanisms remains unknown. Previous work using rodent and primate models leveraged various techniques to suggest that age-related synaptic loss is widespread on pyramidal cells in prefrontal cortex (PFC) circuits but absent on those in area CA1 of the hippocampus. Here, we examined the effect of aging on synapses on projection neurons forming a hippocampal-cortico-thalamic circuit important for spatial working memory tasks from two genetically distinct mouse strains that exhibit susceptibility (C57BL/6J) or resistance (PWK/PhJ) to cognitive decline during aging. Across both strains, synapses on the CA1-to-PFC projection neurons appeared completely intact with age. In contrast, we found synapse loss on PFC-to-nucleus reuniens (RE) projection neurons from aged C57BL/6J but not PWK/PhJ mice. Moreover, synapses from aged PWK/PhJ mice but not from C57BL/6J exhibited morphological changes that suggest increased synaptic efficiency to depolarize the parent dendrite. Our findings suggest resistance to age-related cognitive decline results in part by age-related synaptic adaptations, and identification of these mechanisms in PWK/PhJ mice could uncover new therapeutic targets for promoting successful cognitive aging and extending human health span.
Metabolic Nutrient Preferences ofVibrio mimicus: Leveraging Nucleotides and Oligopeptides from Yellow Catfish for Enhanced Infectivity
Authors: Feng Yang , Wang Jiao , Fan Wei , Geng Yi , Huang Xiaoli , Ouyang Ping , Chen Defang , Guo Hongrui , Deng Huidan , Lai Weimin , Zuo Zhicai , Zhong Zhijun
Published: July 2023

In the context of host-microbe interactions, the microenvironment plays a critical role in facilitating microbial survival, and variations in these microenvironments may influence the pathogenicity of microorganisms.Vibrio mimicus, a major pathogen responsible for infections in aquatic animals, poses a substantial threat to yellow catfish (Pelteobagrus fulvidraco) and grass carp (Ctenopharyngodon idella), two naturally occurring hosts displaying markedly different susceptibility levels. This study aims to unravel the underlying mechanisms behind this susceptibility discrepancy in the two teleost species. Employing metabolomic analysis, we identified a distinctive microenvironment in yellow catfish, characterized by abundant purine nucleotides and oligopeptides. Furthermore, a total of 67 specific metabolites were identified from both yellow catfish and grass carp, with 33 displaying heightened expression on the body surface of yellow catfish, including nucleotides, amino acids, and gangliosides, while 34 were predominantly expressed on the body surface of grass carp, primarily comprising lipids. Subsequent investigations revealed that certain compounds related to nucleotides and oligopeptides exhibited significant growth-promoting effects and were utilized byV. mimicusas nutrients, with deoxyguanosine proving to be notably more than twice as effective as glucose. Moreover, duringV. mimicusinfection, numerous metabolites such as oligopeptides, purine nucleotides, and specific metabolites experienced considerable depletion in the skin of yellow catfish. Concurrently, several genes associated with nucleosidase and peptidase were upregulated in the skin and muscles of infected fish. These findings suggest that the microenvironment provided by different hosts plays a pivotal role in determining the infectivity of the pathogen. Additionally, our results indicate that the microenvironment on the surface of yellow catfish, characterized by an abundance of purine nucleotides and oligopeptides, indirectly enhancesV. mimicusgrowth, ultimately augmenting its infectivity.
Mechanosensitive ion channel MSL8 is required for pulsatile growth and cell wall dynamics inArabidopsispollen tubes
Authors: Coomey Joshua H. , Haswell Elizabeth S.
Published: July 2023

HIGHLIGHT

Pollen tube growth requires tight control of apical wall expansion. We present evidence for a mechanosensitive ion channel, MSL8, as a braking signal in growth dynamics through cell wall regulation.

The male gametophyte in flowering plants, pollen, both performs the critical role of fertilization and represents a unique and accessible system for interrogating plant cell mechanics. Pollen endures multiple mechanical hurdles during its lifecycle: desiccation in the anther, rapid rehydration on the stigma, and germination to produce a rapidly growing pollen tube that will eventually reach the ovule. A key component in this robust mechanical system is MscS-Like 8 (MSL8), a mechanosensitive ion channel. We previously proposed that that MSL8 serves as an “osmotic safety valve”, regulating pressure in the germinating pollen tube by releasing anions in response to plasma membrane tension, thereby preventing pollen tube rupture. However, we subsequently identified defects in the cell walls ofmsl8mutant pollen, suggesting that it plays a role independent of osmoregulation, a conclusion also supported by mathematical modeling. Here, we show that pollen tubes lacking MSL8 channel function by genetic knockout or channel-blocking point mutation lose major growth pauses, have altered pectin esterification patterns, and are sensitive to pectin crosslinking. Together, these data suggest a mechanism whereby tension-gated ion release through mechanosensitive channels regulates apoplastic function and cell wall dynamics.
Phylogenetic Analysis of a Bacterial Strain of the GenusRothiaDetected in Suspension Culture Cells ofArabidopsis thaliana(L.) Heynh as a Member of the FamilyMicrococcaceae
Authors: Shchyogolev Sergei , Dykman Lev , Sokolov Alexander , Sokolov Oleg , Matora Larisa
Published: July 2023

We report phylogenetic studies of a bacterial isolate (Isolate SG) recovered from a suspension culture ofArabidopsis thaliana(L.) Heynh. In doing this, we use the known results acquired by whole genome sequencing of the DNA ofMicrococcaceaestrains closely related to Isolate SG in the 16S rRNA gene test and we evaluate the intra- and intergeneric taxonomic relationships between them using a set of five whole genome tests (ANI, AAI, MiGA, GTDB-Tk, and AAI-profiler). Quantitative analysis of the clustering of the proteomes of these strains by the average amino acid identity (AAI)-based test showed the need to clarify (with possible renaming) the generic assignment of the strains both within and between the identified monophyletic groups. The need for such reclassification was also shown by the AAI-profiler test (Medlaret al., 2018) against the UniProt database (250 million records) with the proteome ofRothiasp. ND6WE1A – a strain most evolutionarily similar to Isolate SG. The contradictions in the historically given names of strains and metagenomic objects at the genus and family levels, which were identified by using sets of the genomes and proteomes of the strains related to Isolate SG, can be eliminated with appropriate reclassification of the objects by using quantitative criteria in the AAI-based tests.
Enhanced microglial dynamics and paucity of tau seeding in the amyloid plaque microenvironment contributes to cognitive resilience in Alzheimer’s disease
Authors: Jury-Garfe Nur , You Yanwen , Martínez Pablo , Redding-Ochoa Javier , Karahan Hande , Johnson Travis S. , Zhang Jie , Kim Jungsu , Troncoso Juan C. , Lasagna-Reeves Cristian A.
Published: July 2023

Asymptomatic Alzheimer’s disease (AsymAD) describes the status of subjects with preserved cognition but with identifiable Alzheimer’s disease (AD) brain pathology (i.e. Aβ-amyloid deposits, neuritic plaques, and neurofibrillary tangles) at autopsy. In this study, we investigated the postmortem brains of a cohort of AsymAD cases to gain insight into the underlying mechanisms of resilience to AD pathology and cognitive decline. Our results showed that AsymAD cases exhibit an enrichment of core plaques and decreased filamentous plaque accumulation, as well as an increase in microglia surrounding this last type. In AsymAD cases we found less pathological tau aggregation in dystrophic neurites compared to AD and tau seeding activity comparable to healthy control subjects. We used spatial transcriptomics to further characterize the plaque niche and found autophagy, endocytosis, and phagocytosis within the top upregulated pathways in the AsymAD plaque niche, but not in AD. Furthermore, we found ARP2, an actin-based motility protein crucial to initiate the formation of new actin filaments, increased within microglia in the proximity of amyloid plaques in AsymAD. Our findings support that the amyloid-plaque microenvironment in AsymAD cases is characterized by microglia with highly efficient actin-based cell motility mechanisms and decreased tau seeding compared to AD. These two mechanisms can potentially provide protection against the toxic cascade initiated by Aβ that preserves brain health and slows down the progression of AD pathology.
The mRNACalc web server accounts for the hypochromicity of modified nucleosides and enables the accurate quantification of nucleoside-modified mRNA
Authors: Finol Esteban , Krul Sarah E. , Hoehn Sean J. , Crespo-Hernández Carlos E.
Published: July 2023

Nucleoside-modified mRNA technologies necessarily incorporate N1-methylpseudouridine into the mRNA molecules to prevent over-stimulation of cytoplasmic RNA sensors. Despite this modification, mRNA concentrations remain mostly determined through measurement of UV absorbance at 260 nm wavelength (A260). Herein, we report that the N1-methylpseudouridine absorbs approximately 40% less UV light at 260 nm than uridine, and its incorporation into mRNAs leads to the under-estimation of nucleoside-modified mRNA concentrations, with 5-15% error, in a mRNA sequence dependent manner. We therefore examined the RNA quantification methods and developed the mRNACalc web server. It accounts for the molar absorption coefficient of modified nucleotides at 260 nm wavelength, the RNA composition of the mRNA, and the A260of the mRNA sample to enable accurate quantification of nucleoside-modified mRNAs. The webserver is freely available athttps://www.mrnacalc.com.

Graphical Abstract
Heterogeneous identity, stiffness and growth characterise the shoot apex ofArabidopsisstem cell mutants
Authors: Rambaud-Lavigne Léa , Chatterjee Aritra , Bovio Simone , Battu Virginie , Lavigne Quentin , Gundiah Namrata , Boudaoud Arezki , Das Pradeep
Published: July 2023

Stem cell homeostasis in the shoot apical meristem involves a core regulatory feedback loop between the signalling peptide CLAVATA3, produced in stem cells, and the transcription factor WUSCHEL, expressed in the underlying organising centre.clavatamutants display massive meristem overgrowth, which is thought to be caused by stem cell overproliferation, although it is unknown how uncontrolled stem cell divisions lead to this altered morphology. Here we first reveal local buckling defects in mutant meristems, and use analytical models to show how mechanical properties and growth rates may contribute to the phenotype. Indeed,clavatameristems are mechanically more heterogeneous than the wild type, and also display regional growth heterogeneities. Furthermore, stereotypical wild-type meristem organisation is lost in mutants, in which cells simultaneously express distinct fate markers. Finally, cells in mutant meristems are auxin responsive, suggesting that they are functionally different from wild-type stem cells. Thus all benchmarks show thatclavatameristem cells are different from wild-type stem cells, suggesting that fasciation is caused by the disruption of a more complex regulatory framework that maintains distinct genetic and functional domains at the shoot apex.

Summary statement

Heterogeneities in cell mechanics, growth, function and identity contribute to buckling inclavatamutant shoot apices.
N-(5-Cyanononan-5-yl)benzamide
Authors: Song Xueqing , Li William
Published: July 2023

N-(5-Cyanononan-5-yl)benzamide, C17H24N2O, synthesized from the reaction between benzoyl chloride and 2-amino-2-butylhexanenitrile, is an important intermediate in amino acid synthesis. Intermolecular N—H...O and C—H...O hydrogen bonds with N...O and C...O distances of 3.083 (2) and 3.304 (2) Å, respectively, link adjacent molecules into chains along the a axis. The dihedral angle between the mean plane of the phenyl group and the plane of the amide group is 19.504 (4)°.
Value proposition-driven reconfiguration of business models in dynamic industries: a design-science approach
Authors: Kouptsov Alexander , Srai Jagjit Singh
Published: July 2023

Purpose

This paper aims to better understand and structure the process of business model (BM) redesign in dynamic industry contexts by exploring the interactions of BM components through a configuration and design-science lens. While these interactions have been investigated broadly in the BM literature, detailed studies on their properties and structures are limited.

Design/methodology/approach

A design-science methodology was utilised to conceptualise a BM design artefact based on literature, the components' interactions of which were investigated and iteratively validated through a case study of an organisation going through a BM change. The artefact served as a framework to capture the case firm's BM and value proposition through semi-structured interviews.

Findings

The results suggest that the interaction of BM components is represented by the value proposition as an integrating mechanism, which can be expressed as a combination of tangible, intangible and monetary inter-component flows. The value proposition, rather than being pre-determined and static, is dynamic and evolves as its flows are exchanged across the value creation, delivery, customer and capture components of the BM. These exchanges and interactions are facilitated by the components' input-process-output capabilities and drive BM reconfiguration through five value flow “properties”, expressed in terms of change in quantity, speed/frequency, composition, quality and value.

Research limitations/implications

While developed with inputs from a complex business environment that provides a rich research context, this work acknowledges the trade-off between in-depth single case analysis in theory building, and the need for follow-on research to address the limiting contextual variables and extend generalisability.

Practical implications

The study offers a framework-based sequence of activities that managers can adopt for the BM design process in dynamic industry environments.

Originality/value

This work contributes to BM theory by setting out a mechanism that helps better understand interactions of BM components in dynamic environments, while also challenging the established definition of the value proposition concept – a key BM component – thus presenting significant implications for theory.
Transforming a provincial archive through the collection of sports memories: experiences of the Gauteng province in South Africa
Authors: Ngoepe Mpho , Mbuyisa Sizwe , Saurombe Nampombe , Matshotshwane Joseph
Published: July 2023

Purpose

South African public archives have not been able to transform into active documenters of society. As a result, they cannot carry out their mandate of collecting non-public records of lasting value and national significance and recording aspects of the country’s experience that have previously been ignored by archives repositories. This paper aims to discuss efforts by the Gauteng Provincial Archives to transform the archival landscape in South Africa by collecting sports memories. This is because, in democratic South Africa, the archival landscape was expected to change and reflect the nation’s diversity, despite the fact that it still largely reflected the Western-dominated global mainstream.

Design/methodology/approach

This study is based on the authors’ personal experiences with the development and operation of the Gauteng Provincial Archives. The authors are also involved in the Gauteng Provincial Archives’ oral history project, which aims to build an inclusive archive by recording oral histories of sports memories across the province.

Findings

The construction of the Gauteng Archives Repository has ushered in a chance to decolonise South African archives by collecting sports memories. These are windows of opportunity through which ordinary people can include their own experiences, filling in the gaps left by colonial and apartheid archives.

Originality/value

This paper offers practical experience in transforming and decolonising archives through collecting sports memories.
The effect of cultural differences on the relationship between contract governance and opportunism
Authors: Wang Tao , Han Linhao , Yang Zhilin , Jia Yu
Published: July 2023

Purpose

The purpose of this study is to determine the dimensions of cultural differences, which are theoretically most relevant to contract functions in international marketing. Moreover, the contradiction between contract governance and opportunism is reconciled by exploring the boundary conditions of specific cultural differences.

Design/methodology/approach

The authors obtained 235 bilateral data provided by Chinese exporters and overseas distributors. The authors matched a secondary data set with the questionnaire data, which were analyzed by confirmatory factor analysis and a hierarchical moderation model.

Findings

The results demonstrate that while contract specificity is less successful in this area, contingency adaptability is useful in reducing opportunism. Moreover, as the national cultural differences regarding uncertainty avoidance, power distance or individualism-collectivism become more pronounced. One contractual dimension will be more effective at curbing opportunism, while the other will be less effective.

Research limitations/implications

Despite sample limitations, to the best of the authors’ knowledge, this paper is the first to theoretically identify the effect of cultural difference dimensions in contract governance, unlike past studies taking cultural differences as an aggregated variable. Furthermore, by exploring the boundary conditions of cultural differences, this paper effectively reconciles the conflicting findings on the relationship between contract governance and opportunism in various cultural context.

Practical implications

Exporters’ managers can design contingency adaptability to complement the limitations of contract specificity and consider cultural differences’ contingency effects.

Originality/value

First, the authors identify cultural differences dimensions related to contract governance, refining and emphasizing the research context. Second, comparing the efficacy of contract specificity and contingency adaptability in specific cultural context can show which contract is better at preventing opportunism.
Positioning higher education institutions as work-based ICT-integrated learning theatres for employee mid-career development; a strategy for HR capacity building
Authors: Tumwebaze Alicon Auf , Kalinaki Kassim
Published: July 2023

Purpose

Despite the sporadic evolution of artificial intelligence, the most valuable asset of any organization in the modern world is human resources. This study aims to reveal that partnerships between higher education institutions (HEIs) and employers will ease the process of employee mid-career development in Uganda's corporate employment sector by promoting work-based postgraduate training, and this additionally promotes human resources (HR) capacity-building for organizations.

Design/methodology/approach

The hypothesis is that contemporary employees seek out an academic mid-career development postgraduate programme that is blended to fit into the employees' work schedule. The study was a descriptive quantitative study, and a closed-ended questionnaire was sent out to groups of corporate employees online (N = 70) and 41 responded, giving a response rate of 58.5%.

Findings

Findings indicate a need for a flexible program for mid-career development and transition, the low standard deviation of (Neutral = 0.95, Disagreed = 2.64 and Agreed = 3.3) implies an insignificant deviation from the mean of responses. Indeed, over 95% agree that pursue further studies is needed but in a more flexible way.

Research limitations/implications

The study design was limited by the sample selection process and study design. In the future, the authors recommend a mixed study for both quantitative and qualitative dimensions of such studies.

Practical implications

Irrespective of gender, hierarchy and experience, employees want flexible study modes for their postgraduate. This implies that institutions of higher learning should work with the labour industry and position themselves as work-based information and communication technology (ICT)-Integrated learning theatres.

Originality/value

The move towards a collaborative strategy between academia and the employment industry is very evident in this study.
Retaining hospitality talent during COVID-19: the joint impacts of employee resilience, work social support and proactive personality on career change intentions
Authors: Yang Wan , Lee Patrick C.
Published: July 2023

Purpose

Due to the COVID-19 pandemic, many people have experienced career shocks, especially employees in the hotel industry. To address how to retain talent in the industry, this study aims to examine the joint impacts of employee resilience, work social support and proactive personality on hotel employees’ career change intentions.

Design/methodology/approach

A survey questionnaire was developed to test the proposed framework. Data from 339 current hotel employees in the USA was analyzed using the PROCESS model.

Findings

Results show a significant three-way interaction, indicating that for less proactive employees, resilience is negatively associated with career change intentions. However, for highly proactive employees, an additional situation cue in the form of strong work social support is required to activate the expression of resilience. Highly proactive and resilient employees who receive strong supervisor or coworker support during the pandemic have lower career change intentions. However, highly proactive employees who receive weak supervisor or coworker support exhibit similar levels of career change intentions, regardless of resilience level.

Practical implications

Hotel managers should consider helping employees enhance their resilience and overcome career shocks by providing training and resources and establishing a learning culture. More importantly, it is essential to offer strong supervisor and coworker support to promote resilience among proactive employees. Hotel managers should actively promote strong work social support, and offer training and counseling opportunities to promote employee retention during the pandemic.

Originality/value

To the best of the authors’ knowledge, this study is the first to examine employee resilience in the hospitality field. This study contributes to the employee resilience literature as well as trait activation theory by examining situational cues that can activate employee resilience and by providing empirical evidence to reveal the boundary conditions of how employee resilience impacts career change intentions.