Cell Shape Research Articles

Soluble αβ-tubulins reversibly sequester TTC5 to regulate tubulin mRNA decay

AbstractMicrotubules, built from heterodimers of α- and β-tubulins, control cell shape, mediate intracellular transport, and power cell division. The concentration of αβ-tubulins is tightly controlled through a posttranscriptional mechanism involving selective and regulated degradation of tubulin-encoding mRNAs. Degradation is initiated by TTC5, which recognizes tubulin-synthesizing ribosomes and recruits downstream effectors to trigger mRNA deadenylation. Here, we investigate how cells regulate TTC5 activity. Biochemical and structural proteomic approaches reveal that under normal conditions, soluble αβ-tubulins bind to and sequester TTC5, preventing it from engaging nascent tubulins at translating ribosomes. We identify the flexible C-terminal tail of TTC5 as a molecular switch, toggling between soluble αβ-tubulin-bound and nascent tubulin-bound states. Loss of sequestration by soluble αβ-tubulins constitutively activates TTC5, leading to diminished tubulin mRNA levels and compromised microtubule-dependent chromosome segregation during cell division. Our findings provide a paradigm for how cells regulate the activity of a specificity factor to adapt posttranscriptional regulation of gene expression to cellular needs.

Construction of inherent geometric pattern for equal-area hexagonal discrete global grid systems

ABSTRACT Discrete Global Grid Systems (DGGSs) are hierarchical frameworks that provide seamless global coverage and enable the efficient processing and analysis of heterogeneous geospatial data. As cell resolution becomes finer, similarities in cell attributes, such as cell size and shape, increase. Understanding these shared characteristics enhances our knowledge of DGGSs structures, improving their reliability and accuracy across a range of applications. However, existing methods for quantifying these characteristics are limited, often emphasizing overall analysis and visualization rather than detailed assessment. This paper introduces a geometric pattern quantification method for equal-area hexagonal DGGSs by calculating inter-level attribute similarities to identify a reference level, segmenting the spatial distribution image at this reference level, and fitting the boundaries of these sub-images to create iso-feature lines. The results show that this method improves the accuracy and efficiency of cell attribute calculations, with enhancements of at least 5.6 times for study regions and 13.8 times for sample points at lower levels. This pattern provides a robust basis for grid selection and optimization in regional applications, promoting the broader adoption of DGGSs across various fields.

MinD2 modulates cell shape and motility in the archaeon Haloferax volcanii

In bacteria and archaea, proteins of the ParA/MinD family of ATPases regulate the spatiotemporal organization of various cellular cargoes, including cell division proteins, motility structures, chemotaxis systems, and chromosomes. In bacteria, such as Escherichia coli, MinD proteins are crucial for the correct placement of the Z-ring at mid-cell during cell division. However, previous studies have shown that none of the 4 MinD homologs present in the archaeon Haloferax volcanii have a role in cell division, suggesting that these proteins regulate different cellular processes in haloarchaea. Here, we show that while deletion of MinD2 in H. volcanii (∆minD2) does not affect cell growth or division, it impacts cell shape and motility by mispositioning the chemotaxis arrays and archaellum motors. Finally, we explore the links between MinD2 and MinD4, which has been previously shown to modulate the localization of chemosensory arrays and archaella in H. volcanii, finding that the two MinD homologues have synergistic effects in regulating the positioning of the motility machinery. Collectively, our findings identify MinD2 as an important link between cell shape and motility in H. volcanii and further our understanding of the mechanisms by which multiple MinD proteins regulate cellular functions in haloarchaea.

Analysis of Cell Wall Mechanics in Fission Yeast.

The growth and shape of fungal cells, such as fission yeast, are strongly constrained by the mechanics of their cell wall (CW). The cell wall encases the plasma membrane and defines instantaneous cell shapes by opposing turgor pressure-derived stress on the cell surface. Measuring cell wall mechanical properties may thus bring key insights into the regulation of cell morphogenesis, cell growth, but also cell surface integrity and survival. The fission yeast cell wall has a thickness of a few tens to hundreds of nanometers, and bulk elasticity similar to that of rubber (tens of MPa). These mechanical properties vary locally around single cells, for instance, at the new vs. old growing ends, or birth scars, and may also largely depend on growth conditions and life cycle phases. While cell wall thickness and mechanics have been traditionally measured by complex methodologies including electron microscopy and atomic force microscopy, we here propose a method based on light microscopy to infer with medium-throughput cell wall mechanical properties, as well as turgor pressure in time and space in living cells. This analysis will enhance our appreciation of the mechanical regulation of fission yeast cell morphogenesis and may be directly transferable to the study of other fungal cells.

Design and Performance of High-Capacity Magnesium–Air Battery for Power Generator System

Efforts to achieve carbon neutrality, which aims to reduce the net carbon emissions to zero by decreasing carbon emissions from human activities and increasing carbon absorption, are actively underway. Additionally, the search for clean energy alternatives to fossil fuels has become a global research trend. This paper presents research on metal–air batteries, focusing on the development of energy supply technologies that do not generate carbon emissions during power generation and require less space for power generation compared to existing renewable energy sources. The proposed Mg–air battery (MAB) in this study uses magnesium as the metal anode and theoretically offers a maximum open-circuit voltage of 3.1 V and a high energy density of 6.8 kWh/kg. While previous research has primarily focused on designing small-capacity cells and maximizing the performance of metal anodes, this study differentiates itself by designing a large-capacity MAB cell and optimizing its electrical performance. For the large-capacity cell design, the weight, shape, and size of the anode were designed based on MAB performance factors, and research was conducted on manufacturing methods to optimize the performance of the air cathode. Furthermore, to enhance usability and extend the lifespan of the MAB cell, it was designed to allow electrolyte circulation, and the electrolyte circulation performance was verified through simulations of fluid flow within the cell. Based on the study of the power performance of the newly designed large-capacity MAB cell, the feasibility of constructing a kW-class system using multiple Mg–air battery cell stacks was confirmed.

Morphological and Optical Profiling of Melanocytes and SK-MEL-28 Melanoma Cells Via Digital Holographic Microscopy and Quantitative Phase Imaging.

Melanoma, which originates from pigment-producing melanocytes, is an aggressive and deadly skin cancer. Despite extensive research, its mechanisms of progression and metastasis remain unclear. This study uses quantitative phase imaging via digital holographic microscopy, Principal Component Analysis (PCA), and t-distributed Stochastic Neighbor Embedding (t-SNE) to identify the morphological, optical, and behavioral differences between normal melanocytes and SK-MEL-28 melanoma cells. Our findings reveal significant differences in cell shape, size, and internal organization, with SK-MEL-28 cells displaying greater size variability, more polygonal shapes, and higher optical thickness. Phase shift parameters and surface roughness analyses underscore melanoma cells' uniform and predictable textures. Violin plots highlight the dynamic and varied migration of SK-MEL-28 cells, contrasting with the localized movement of melanocytes. Hierarchical clustering of correlation matrices provides further insights into complex morphological and optical relationships. Integrating label-free imaging with robust analytical methods enhances understanding of melanoma's aggressive behavior, supporting targeted therapies and highlighting potential biomarkers for precise melanoma diagnostics and treatment.

Exploring the impact of lipid stress on sperm cytoskeleton: insights and prospects.

The decline in male fertility correlates with the global rise in obesity and dyslipidaemia, representing significant public health challenges. High-fat diets induce metabolic alterations, including hypercholesterolaemia, hepatic steatosis and atherosclerosis, with detrimental effects on testicular function. Testicular tissue, critically dependent on lipids for steroidogenesis, is particularly vulnerable to these metabolic disruptions. Excessive lipid accumulation within the testes, including cholesterol, triglycerides and specific fatty acids, disrupts essential sperm production processes such as membrane formation, maturation, energy metabolism and cell signalling. This leads to apoptosis, impaired spermatogenesis, and abnormal sperm morphology and function, ultimately compromising male fertility. During spermiogenesis, round spermatids undergo extensive reorganization, including the formation of the acrosome, manchette and specialized filamentous structures, which are essential for defining the final sperm cell shape. In this Perspective, we examine the impact of high-fat diets on the cytoskeleton of spermatogenic cells and its consequences to identify the mechanisms underlying male infertility associated with dyslipidaemia. Understanding these processes may facilitate the development of therapeutic strategies, such as dietary interventions or natural product supplementation, that aim to address infertility in men with obesity and hypercholesterolaemia. The investigation of cytoskeleton response to lipid stress extends beyond male reproduction, offering insights with broader implications.

Cell shape affects bacterial colony growth under physical confinement

Evidence from homogeneous liquid or flat-plate cultures indicates that biochemical cues are the primary modes of bacterial interaction with their microenvironment. However, these systems fail to capture the effect of physical confinement on bacteria in their natural habitats. Bacterial niches like the pores of soil, mucus, and infected tissues are disordered microenvironments with material properties defined by their internal pore sizes and shear moduli. Here, we use three-dimensional matrices that match the viscoelastic properties of gut mucus to test how altering the physical properties of their microenvironment influences the growth of bacteria under confinement. We find that low aspect ratio (spherical) bacteria form compact, spherical colonies under confinement while high aspect ratio (rod-shaped) bacteria push their progenies further outwards to create elongated colonies with a higher surface area, enabling increased access to nutrients. As a result, the population growth of high aspect ratio bacteria is, under the tested conditions, more robust to increased physical confinement compared to that of low aspect ratio bacteria. Thus, our experimental evidence supports that environmental physical constraints can play a selective role in bacterial growth based on cell shape.

Alteration of Cytoskeletal Proteins Leads to Retinal Degeneration in Drosophila.

The eye holds a special fascination for many neuroscientists because of its meticulously organized structure. Vertebrates typically possess a simple camera-type eye, whereas the compound eye structure is predominantly observed in arthropods including model organism Drosophila melanogaster. Cell shape, cell polarization, and tissue integrity are the cell biological processes crucial for shaping the eye, which directly or indirectly depends on the cytoskeleton. Henceforth the cytoskeleton, specifically actin microfilaments, essentially has a dynamic role in the normal development and growth of eye structure. This review provides insight into the roles played by the actin cytoskeleton during the development and maintenance of the Drosophila eye.

Myh9b is a critical non-muscle myosin II encoding gene that interacts with myh9a and myh10 during zebrafish development in both compensatory and redundant pathways.

Non-muscle myosin (NMII) motor proteins have diverse developmental functions due to their roles in cell shape changes, cell migration, and cell adhesion. Zebrafish are an ideal vertebrate model system to study the NMII encoding myh genes and proteins due to high sequence homology, established gene editing tools, and rapid ex utero development. In humans, mutations in the NMII encoding MYH genes can lead to abnormal developmental processes and disease. This study utilized zebrafish myh9a, myh9b, and myh10 null mutants to examine potential genetic interactions and roles for each gene in development. It was determined that the myh9b gene is the most critical NMII encoding gene, as myh9b mutants develop pericardial edema and have a partially penetrant lethal phenotype, which was not observed in the other myh mutants. This study also established that genetic interactions occur between the zebrafish myh9a, myh9b, and myh10 genes where myh9b is required for the expression of both myh9a and myh10, and myh10 is required for the expression of myh9b. Additionally, protein analyses suggested that enhanced NMII protein stability in some mutant backgrounds may play a role in compensation. Finally, double mutant studies revealed different and more severe phenotypes at earlier timepoints than single mutants, suggesting roles for tissue specific genetic redundancy, and in some genotypes, haploinsufficiency. These mutants are the first in vivo models allowing for the study of complete loss of the NMIIA and NMIIB proteins, establishing them as valuable tools to elucidate the role of NMII encoding myh genes in development and disease.

The unique role of vimentin in the intermediate filament proteins family

Intermediate filaments (IFs), being traditionally the least studied component of the cytoskeleton, have begun to receive more attention in recent years. IFs are found in different cell types and are specific to them. Accumulated data have shifted the paradigm about the role of IFs as structures that merely provide mechanical strength to the cell. In addition to this role, IFs have been shown to participate in maintaining cell shape and strengthening cell adhesion. The data have also been obtained that point out to the role of IFs in a number of other biological processes, including organization of microtubules and microfilaments, regulation of nuclear structure and activity, cell cycle control, and regulation of signal transduction pathways. They are also actively involved in the regulation of several aspects of intracellular transport. Among the intermediate filament proteins, vimentin is of particular interest for researchers. Vimentin has been shown to be associated with a range of diseases, including cancer, cataracts, Crohn’s disease, rheumatoid arthritis, and HIV. In this review, we focus almost exclusively on vimentin and the currently known functions of vimentin intermediate filaments (VIFs). This is due to the structural features of vimentin, biological functions of its domains, and its involvement in the regulation of a wide range of basic cellular functions, and its role in the development of human diseases. Particular attention in the review will be paid to comparing the role of VIFs with the role of intermediate filaments consisting of other proteins in cell physiology.

Cyclic stretch regulates epithelial cell migration in a frequency dependent manner via intercellular vinculin recruitment

The epithelial microenvironment is incredibly dynamic, subjected to mechanical cues including cyclic stretch. While cyclic cell stretching platforms have revealed epithelial cell reorientation and gap formation, few studies have investigated the long-term effects of cyclic stretch on cell migration. We measured the migratory response of the epithelium to a range of physiologically relevant frequencies and stretch. Our results indicate that lower stretch frequencies (i.e., 0.1 Hz) suppress epithelial migration, accompanied by cell reorientation and high cell shape solidity. We found that this response is also accompanied by increased recruitment of vinculin to cell-cell contacts, and this recruitment is necessary to suppress cell movements. These results confirm the mechanosensitive nature of vinculin within the adherens junction, but independently reveal a novel mechanism of low frequency stress response in supporting epithelial integrity by suppressing cell migration.

Exploring heterogeneous cell population dynamics in different microenvironments by novel analytical strategy based on images.

Understanding the dynamic states and transitions of heterogeneous cell populations is crucial for addressing fundamental biological questions. High-content imaging provides rich datasets, but it remains increasingly difficult to integrate and annotate high-dimensional and time-resolved datasets to profile heterogeneous cell population dynamics in different microenvironments. Using hepatic stellate cells (HSCs) LX-2 as model, we proposed a novel analytical strategy for image-based integration and annotation to profile dynamics of heterogeneous cell populations in 2D/3D microenvironments. High-dimensional features were extracted from extensive image datasets, and cellular states were identified based on feature profiles. Time-series clustering revealed distinct temporal patterns of cell shape and actin cytoskeleton reorganization. We found LX-2 showed more complex membrane dynamics and contractile systems with an M-shaped actin compactness trend in 3D culture, while they displayed rapid spreading in early 2D culture. This image-based integration and annotation strategy enhances our understanding of HSCs heterogeneity and dynamics in complex extracellular microenvironments.

Quantifying the fractal complexity of nutrient transport channels in Escherichia coli biofilms under varying cell shape and growth environment.

Recent mesoscopic characterization of nutrient-transporting channels in Escherichia coli has allowed the identification and measurement of individual channels in whole mature colony biofilms. However, their complexity under different physiological and environmental conditions remains unknown. Analysis of confocal micrographs of colony biofilms formed by cell shape mutants of E. coli shows that channels have high fractal complexity, regardless of cell phenotype or growth medium. In particular, colony biofilms formed by the mutant strain ΔompR, which has a wide-cell phenotype, have a higher fractal dimension when grown on rich medium than when grown on minimal medium, with channel complexity affected by glucose and agar concentrations in the medium. Osmotic stress leads to a dramatic reduction in the ΔompR cell size but has a limited effect on channel morphology. This work shows that fractal image analysis is a powerful tool to quantify the effect of phenotypic mutations and growth environment on the morphological complexity of internal E. coli biofilm structures. If applied to a wider range of mutant strains, this approach could help elucidate the genetic determinants of channel formation in E. coli colony biofilms.

Disease Prediction using Classification of Blood Cells Smear Images

This study presents a unified system for classifying blood cells, predicting blood-related diseases, and providing personalized dietary recommendations. The system uses a Convolutional Neural Network (CNN) to classify blood cells from microscopic images into categories like red blood cells (RBCs), white blood cells (WBCs), and platelets. Extracted features such as cell size, shape, and texture improve classification accuracy. A machine learning model combines the classification results with optional patient data (e.g., age, hemoglobin levels) to predict diseases such as anemia or leukemia. Following disease prediction, a rule-based module offers dietary recommendations, such as iron-rich foods for anemia. The system is designed for healthcare providers and patients, with a user-friendly interface for data input and result visualization. This framework integrates diagnostic automation with personalized nutrition, supporting early detection and health management

RhoA regulates oligodendrocyte differentiation and myelination by orchestrating cortical and membrane tension.

Timely differentiation and myelin formation by oligodendrocytes are essential for the physiological functioning of the central nervous system (CNS). While the Rho GTPase RhoA has been hinted as a negative regulator of myelin sheath formation, the precise in vivo mechanisms have remained elusive. Here we show that RhoA controls the timing and progression of myelination by oligodendrocytes through a fine-tuned balance between cortical tension, membrane tension and cell shape. Using a conditional mouse model, we observe that Rhoa ablation results in the acceleration of myelination driven by hastened differentiation and facilitated through membrane expansion induced by changes in MLCII activity and in F-actin redistribution and turnover within the cell. These findings reveal RhoA as a central molecular integrator of alterations in actin cytoskeleton, actomyosin contractility and membrane tension underlying precise morphogenesis of oligodendrocytes and normal myelination of the CNS.

Single-cell morphometrics reveals T-box gene-dependent patterns of epithelial tension in the Second Heart field

The vertebrate heart tube extends by progressive addition of epithelial second heart field (SHF) progenitor cells from the dorsal pericardial wall. The interplay between epithelial mechanics and genetic mechanisms during SHF deployment is unknown. Here, we present a quantitative single-cell morphometric analysis of SHF cells during heart tube extension, including force inference analysis of epithelial stress. Joint spatial Principal Component Analysis reveals that cell orientation and stress direction are the main parameters defining apical cell morphology and distinguishes cells adjacent to the arterial and venous poles. Cell shape and mechanical forces display a dynamic relationship during heart tube formation. Moreover, while the T-box transcription factor Tbx1 is necessary for cell orientation towards the arterial pole, activation of Tbx5 in the posterior SHF correlates with the establishment of epithelial stress and SHF deletion of Tbx5 relaxes the progenitor epithelium. Integrating findings from cell-scale feature patterning and mechanical stress provides new insights into cardiac morphogenesis.

Unsupervised cervical cell instance segmentation method integrating cellular characteristics.

Cell instance segmentation is a key technology for cervical cancer auxiliary diagnosis systems. However, pixel-level annotation is time-consuming and labor-intensive, making it difficult to obtain a large amount of annotated data. This results in the model not being fully trained. In response to these problems, this paper proposes an unsupervised cervical cell instance segmentation method that integrates cell characteristics. Cervical cells have a clear corresponding structure between the nucleus and cytoplasm. This method fully takes this feature into account by building a dual-flow framework to locate the nucleus and cytoplasm and generate high-quality pseudo-labels. In the nucleus segmentation stage, the position and range of the nucleus are determined using the standard cell-restricted nucleus segmentation method. In the cytoplasm segmentation stage, a multi-angle collaborative segmentation method is used to achieve the positioning of the cytoplasm. First, taking advantage of the self-similarity characteristics of pixel blocks in cells, a cytoplasmic segmentation method based on self-similarity map iteration is proposed. The pixel blocks are mapped from the perspective of local details, and the iterative segmentation is repeated. Secondly, using low-level features such as cell color and shape, a self-supervised heatmap-aware cytoplasm segmentation method is proposed to obtain the activation map of the cytoplasm from the perspective of global attention. The two methods are fused to determine cytoplasmic regions, and combined with nuclear locations, high-quality pseudo-labels are generated. These pseudo-labels are used to train the model cyclically, and the loss strategy is used to encourage the model to discover new object masks, thereby obtaining a segmentation model with better performance. Experimental results show that this method achieves good results in cytoplasm segmentation. On the three datasets of ISBI, MS_CellSeg, and Cx22, 54.32%, 44.64%, and 66.52% AJI were obtained, respectively, which is better than other typical unsupervised methods selected in this article.

Pharmacognostic Standardization and Chemical Study of Euphorbia nutans Lag. Euphorbiaceae

Aims: This study was designed to set macro/micro morphological standards, phytochemical and physicochemical parameters for the identification of E. nutans, a traditional remedy for the management of many disesases. Study Design: To establish pharmacognostic standards for proper identification of E. nutans and also study its phytochemicals using Gas Chromatography coupled to Mass Spectrometry (GC-MS). Place and Duration: This work was undertaken at the Department of Pharmacognosy and Natural Medicine, Faculty of Pharmacy, University of Uyo, Uyo, Nigeria for three month spanning from April through June, 2022. Methodology: Examination of microscopic characters, venation, chemomicroscopy, micromeritic properties, fluorescence analysis and phytochemical profiling using Gas Chromatography-Mass Spectrometry (GC-MS) were carried out. Results: Epidermal cell shapes were irregular with undulate-sinuous anticlinal walls. Stomatal distribution was amphistomatic with anisocytic and anomocytic stomata on both surfaces. Areolation was quadrangular, linear and biforked vein termination. The fluorescence characteristics showed the presence of different colours supporting the presence of various phytoconstituents for both leaf and stem. The flow properties for both leaf and stem were poor while GC-MS analysis of the dichloromethane extracts revealed lupeol (64.05%), 2-methylhexacosane (9.37%), stigmasterol (4.16%) and campesterol (1.29%) as major components in the leaf while campesterol (0.67%), stigmasterol (2.15 %), beta.-sitosterol (6.22%), lupeol (9.85%) and vitamin E (1.05%) for the stem extract. Conclusion: The results of the study could be useful for correct identification, standardization and preparation of monograph.

The Effect of the Acid-Base Imbalance on the Shape and Structure of Red Blood Cells.

Red blood cells respond to fluctuations in blood plasma pH by changing the rate of biochemical and physical processes that affect the specific functions of individual cells. This study aimed to analyze the effect of pH changes on red blood cell morphology and structure. The findings revealed that an increase or decrease in pH above or below the physiological level of pH 7.4 results in the transformation of discocytes into echinocytes and causes significant alterations in the membrane, including its roughness, cytoskeleton structure, and the cell's elastic modulus. Furthermore, the study shown a strong connection between critical acidosis and alkalosis with increased intracellular reactive oxygen species production.