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Human prenatal skin is populated by innate immune cells, including macrophages, but whether they act solely in immunity or have additional functions in morphogenesis is unclear. Here we assembled a comprehensive multi-omics reference atlas of prenatal human skin (7-17 post-conception weeks), combining single-cell and spatial transcriptomics data, to characterize the microanatomical tissue niches of the skin. This atlas revealed that crosstalk between non-immune and immune cells underpins the formation of hair follicles, is implicated in scarless wound healing and is crucial for skin angiogenesis. We systematically compared a hair-bearing skin organoid (SkO) model derived from human embryonic stem cells and induced pluripotent stem cells to prenatal and adult skin1. The SkO model closely recapitulated in vivo skin epidermal and dermal cell types during hair follicle development and expression of genes implicated in the pathogenesis of genetic hair and skin disorders. However, the SkO model lacked immune cells and had markedly reduced endothelial cell heterogeneity and quantity. Our in vivo prenatal skin cell atlas indicated that macrophages and macrophage-derived growth factors have a role in driving endothelial development. Indeed, vascular network remodelling was enhanced following transfer of autologous macrophages derived from induced pluripotent stem cells into SkO cultures. Innate immune cells are therefore key players in skin morphogenesis beyond their conventional role in immunity, a function they achieve through crosstalk with non-immune cells.

Thrombospondin-4 (TSP-4) belongs to the extracellular matrix glycoprotein family of thrombospondins (TSPs). The multidomain, pentameric structure of TSP-4 allows its interactions with numerous extracellular matrix components, proteins and signaling molecules that enable its modulation to various physiological and pathological processes. Characterization of TSP-4 expression under development and pathogenesis of disorders has yielded important insights into mechanisms underlying the unique role of TSP-4 in mediating various processes including cell-cell, cell-extracellular matrix interactions, cell migration, proliferation, tissue remodeling, angiogenesis, and synaptogenesis. Maladaptation of these processes in response to pathological insults and stress can accelerate the development of disorders including skeletal dysplasia, osteoporosis, degenerative joint disease, cardiovascular diseases, tumor progression/metastasis and neurological disorders. Overall, the diverse functions of TSP-4 suggest that it may be a potential marker or therapeutic target for prognosis, diagnosis, and treatment of various pathological conditions upon further investigations. This review article highlights recent findings on the role of TSP-4 in both physiological and pathological conditions with a focus on what sets it apart from other TSPs.

AbstractThe ability of Candida albicans to switch among yeast, hyphal, and pseudohyphal forms underlies its adaptability and pathogenicity. While cAMP-dependent signaling has long been considered central to hyphal growth, recent multi-omics studies show that cAMP-independent mechanisms also drive morphological changes. Basal PKA activity, cyclin-dependent kinases (e.g., Cdc28), and other regulators can promote shape-shifting even without classical cAMP pathways. In addition, N-acetylglucosamine (GlcNAc) acts as a potent signal that induces hyphal growth independently of its metabolic role, directly connecting environmental cues to morphological states. By integrating transcriptomic, proteomic, and phosphoproteomic data, this review exposes the intricate networks controlling C. albicans morphogenesis. A clearer understanding of these complex regulatory circuits lays the groundwork for future studies that employ advanced multi-omics analyses. Such approaches will help elucidate how these pathways converge, how they respond to changing environments, and how they might be harnessed or disrupted to influence fungal behavior. [ABSTRACT FROM AUTHOR]

Precisely controlled remodeling of the basement membrane (BM) is crucial for morphogenesis, but its molecular and tissuelevel dynamics, underlying mechanisms, and functional significance in mammals remain largely unknown due to limited visualization tools. We developed mouse lines in which the endogenous collagen IV gene (Col4a2) was fused with a fluorescent tag. Through live imaging of developing hair follicles, we reveal a spatial gradient in the turnover rate of COL4A2 that is closely coupled with both the BM expansion rate and the proliferation rate of epithelial progenitors. Epithelial progenitors are displaced with directionally expanding BMs but do not actively migrate on stationary BM. The addition of a matrix metalloproteinase inhibitor delays COL4A2 turnover, restrains BM expansion, and increases perpendicular divisions of epithelial progenitors, altering hair follicle morphology. Our findings highlight the spatially distinct dynamics of BM and their key roles in orchestrating progenitor cell behavior and organ shape during development. [ABSTRACT FROM AUTHOR]

Cyclin-dependent kinase 7 (CDK7) is the catalytic subunit of CDK-activating kinase (CAK), which phosphorylates CDK1/2/4/6 and RNA polymerase II (Pol II) to promote cell cycle progression and gene transcription, respectively. CDK7 plays critical roles in development and homeostasis. CDK7 is overexpressed in a variety of cancers. CDK7 inhibitors are promising anticancer agents currently being evaluated in clinical trials. Activation of CDK7 has been associated with diseases beyond cancer. Cyclin-dependent kinase 7 (CDK7) regulates cell cycle and transcription, which are central for cancer progression. CDK7 inhibitors exhibit substantial anticancer activities in preclinical studies and are currently being evaluated in clinical trials. CDK7 is widely expressed in the body. However, the impact of CDK7 inhibition on normal tissues has received little attention. Here, we review the biological functions of CDK7, followed by its emerging roles in development, homeostasis and diseases. We discuss the regulatory mechanisms of CDK7 kinase activation and provide an overview of CDK7 substrates identified to date. Moreover, we highlight unanswered questions and propose key areas for future investigation. An advanced understanding of CDK7 will facilitate the pharmaceutical development of CDK7 inhibitors and help minimize undesirable adverse effects. [ABSTRACT FROM AUTHOR]

The intercropping between BRS Paiaguás (Bachiaria brizantha cv. BRS Paiaguás) and BRS Tamani (Panicum maximum cv. BRS Tamani) cultivars can ensure better utilisation of available abiotic resources, potentially promoting higher forage mass yield. The aim was to investigate the effect of BRS Tamani and BRS Paiaguás cultivars in different cropping systems (monoculture vs. intercropping) in the Brazilian semi-arid region. The experiment was designed with five treatments in randomised blocks, consisting of different proportions of an intercropping system composed of the cultivars mentioned: 100% Paiaguás; 75% Paiaguás and 25% Tamani; 50% Paiaguás and 50% Tamani; 25% Paiaguás and 75% Tamani; and 100% Tamani. The availability of forage mass and tissue flow was evaluated throughout the experimental period. There were differences in the total forage mass between the cultivation systems, with the highest values estimated in pastures with a consortium of 25% Paiaguás and 75% Tamani, 50% Paiaguás and 50% Tamani, and 75% Paiaguás and 25 Tamani, respectively. When there was lower participation of Tamani (25%), the Paiaguás cultivar had a longer leaf lifespan and phyllochron. To ensure balance in forage production in semi-arid regions, it is possible to recommend the implementation of intercropping with 50% Paiaguás and 50% Tamani. [ABSTRACT FROM AUTHOR]

This paper investigates the role of mechanics in the morphogenesis of the annulus of the mitral valve. We represent the annulus in its embryonic stage as an elastic ring and we perform a mechanical simulation of the development process applying a distributed torque on the rod: because of the mechanical action of the other growing cardiac chambers on the atrio-ventricular region, it departs from a planar circular shape. The numerical integration of the mathematical rod model subject to a bending load yields a shape very near to the one reported in the medical literature as anatomical reference for healthy patients. To make the comparison quantitative, we illustrate a numerical approach to match two curves in 3D defining their distance in a proper mathematical way. Such a methodology is first applied to compare the annular shape resulting from the mechanical model with an anatomical reference "master" shape and it is then applied to set to clinical data extracted from MRI for a cohort of healthy patients. The good agreement among anatomical master description, numerical mechanical model, and clinical data supports our speculation about a possible role of mechanics in determining the shape of the mitral valve. [ABSTRACT FROM AUTHOR]

The Diverse Intelligence research seeks to understand commonalities in behavioral competencies across a wide range of implementations. Especially interesting are simple systems that provide unexpected examples of memory, decision-making, or problem-solving in substrates that at first glance do not appear to be complex enough to implement such capabilities. We seek to develop tools to determine minimal requirements for such capabilities, and to learn to recognize and predict basal forms of intelligence in unconventional substrates. Here, we apply novel analyses to the behavior of classical sorting algorithms—short pieces of code studied for many decades. To study these sorting algorithms as a model of biological morphogenesis and its competencies, we break two formerly ubiquitous assumptions: top-down control (instead, each element within an array of numbers can exert minimal agency and implement sorting policies from the bottom up), and fully reliable hardware (instead, allowing elements to be "damaged" and fail to execute the algorithm). We quantitatively characterize sorting activity as traversal of a problem space, showing that arrays of autonomous elements sort themselves more reliably and robustly than traditional implementations in the presence of errors. Moreover, we find the ability to temporarily reduce progress in order to navigate around a defect, and unexpected clustering behavior among elements in chimeric arrays consisting of two different algorithms. The discovery of emergent problem-solving capacities in simple, familiar algorithms contributes a new perspective showing how basal forms of intelligence can emerge in simple systems without being explicitly encoded in their underlying mechanics. [ABSTRACT FROM AUTHOR]

Transcription factors often contain several different functional regions, including DNA-binding domains, and play an important regulatory role in plant growth, development, and the response to external stimuli. YABYY transcription factors are plant-specific and contain two special domains (N-terminal C2C2 zinc-finger and C-terminal helix-loop-helix domains) that are indispensable. Specifically, YABBY transcription factors play key roles in maintaining the polarity of the adaxial-abaxial axis of leaves, as well as in regulating: vegetative and reproductive growth, hormone response, stress resistance, and secondary metabolite synthesis in plants. Recently, the identification and functional verification of YABBY transcription factors in different plants has increased. On this basis, we summarize recent advances in the: identification, classification, expression patterns, and functions of the YABBY transcription factor family. The normal expression and function of YABBY transcription factors rely on a regulatory network that is established through the interaction of YABBY family members with other genes. We discuss the interaction network of YABBY transcription factors during leaf polarity establishment and floral organ development. This article provides a reference for research on YABBY function, plant genetic improvement, and molecular breeding. [ABSTRACT FROM AUTHOR]

Collective cell migration and tissue morphogenesis play a variety of important roles in the development of many species. Tissue morphogenesis often generates mechanical forces that alter cell shapes and arrangements, resembling collective cell migration-like behaviors. Genetic methods have been widely used to study collective cell migration and its like behavior, advancing our understanding of these processes during development. However, a growing body of research shows that collective cell migration during development is not a simple behavior but is often combined with other cellular and tissue processes. In addition, different surrounding environments can also influence migrating cells, further complicating collective cell migration during development. Due to the complexity of developmental processes and tissues, traditional genetic approaches often encounter challenges and limitations. Thus, some methods with spatiotemporal control become urgent in dissecting collective cell migration and tissue morphogenesis during development. Optogenetics is a method that combines optics and genetics, providing a perfect strategy for spatiotemporally controlling corresponding protein activity in subcellular, cellular or tissue levels. In this review, we introduce the basic mechanisms underlying different optogenetic tools. Then, we demonstrate how optogenetic methods have been applied in vivo to dissect collective cell migration and tissue morphogenesis during development. Additionally, we describe some promising optogenetic approaches for advancing this field. Together, this review will guide and facilitate future studies of collective cell migration in vivo and tissue morphogenesis by optogenetics. [ABSTRACT FROM AUTHOR]

Hair color is formed through a series of processes such as melanin synthesis and storage in melanosomes, transfer from melanocytes, and reception by hair matrix cells in the hair bulb. Because gray hair is caused by the deterioration of a single or multiple of these processes, understanding the mechanisms responsible for these processes is crucial for developing therapeutic strategies. Recently, a robust approach for preparing hair follicle organoids (HFOs) was reported, in which hair follicle morphogenesis, including hair shaft elongation, was tracked in vitro. Here, we investigated whether HFOs could be used to assess genes involved in hair pigmentation. HFOs generated hair follicles and pigmented shafts during the in vitro culturing process. The knockdown of genes associated with melanosome production (Bcl2 and Mitf) and transport (MyoX , PAR2 , and Rab11b) significantly increased the number of gray hairs in HFOs. This organoid model may be a promising platform for better understanding hair pigmentation and screening drugs for gray hair. [ABSTRACT FROM AUTHOR]

Tissue engineering, a multidisciplinary research field aiming to revolutionize regenerative medicine, relies on scaffolds for optimal cell cultures and organ development. Decellularized tissue extracellular matrices (dECM) scaffolds, particularly from human amniotic membrane (hAM), show promise in clinical applications. This review discusses the significance of scaffolds, emphasizing dECM-based hAM scaffolds, delving into ECM complexities, decellularization processes, and evaluation methods. Raman spectroscopy emerges as a non-destructive tool for evaluating ECM preservation, presenting potential for quantifying ECM components in hAM before and after decellularization. The review explores the role of hAM as a biomaterial, detailing its composition and characteristics and emphasizes the importance of evaluating ultrastructural components and suggests Raman spectroscopy as a valuable technique for this purpose. [Display omitted] [ABSTRACT FROM AUTHOR]

Arabidopsis MYB transcription factor, AtDUO1 regulates generative cell body (GC) morphogenesis from round to semi and fully elongated forms before pollen mitosis-II (PM II). It was hypothesised that DUO1 might regulate morphogenesis through any of its direct target genes or components of the DUO1-DAZ1 network. The developmental analysis of plants harbouring T-DNA insertions in some DUO1 target genes using light and fluorescence microscopy revealed abnormal GC morphogenesis only in daz1 and daz2, but gcs1, trm16, mapkkk10, mapkkk20, tet11, and tip1 all undergo normal elongation indicating that these target genes have no important roles in morphogenesis or may be redundant. The important regulatory role of DUO1 was confirmed through the observed incomplete rescue of morphogenesis of mutant duo1-1 GCs by DAZ1 and independently by a C-terminally deleted version of DUO1 (DUO1∆C3) lacking activation sequences. The evidence supports the important role of DAZ1 in GC shape partial morphogenesis. The C-terminus of DUO1 may regulate some target genes that affect GC body elongation. Furthermore, an intact DUO1 is shown to be indispensable for GC shape and nucleus elongation and subsequently for timely division and sperm cell morphogenesis. The development of the GC cytoplasmic projection is regulated independently of DUO1, and all its target genes were able to form it.Key message: AtDAZ1 partially regulates GC body morphogenesis at late developmental stages before PMII of the GC, while the C-terminus of DUO1 may control some target genes for this process. An intact DUO1 is indispensable for GC shape and timely division. [ABSTRACT FROM AUTHOR]

Background: Exploring the spiritual cognition of human organ donation registration volunteers, aiming to provide new ideas for promoting the development of organ donation through this perspective. Methods: This qualitative research was conducted following the conventional content analysis method. 10 registered volunteers for human organ donation were selected from July to December 2023 for face-to-face semi-structured interviews. Snowball sampling was employed to select the participants. In-depth semi-structured interviews were conducted for data gathering. Theoretical saturation was achieved through 10 interviews. Colaizzi phenomenological 7-step analysis method was used to analyze the interview content. Results: The spirituality of registered volunteers for human organ donation can be summarized into three themes and seven sub themes: ① Spiritual Understanding (Love & Life Extension, Dedication to society, Death elevates life); ② The Supporting Role of Spirituality (Become a spiritual motivation for a better life, self-transcendence); ③ The Spiritual Emotional Value of Organ Donation (Sense of accomplishment and pride, Sense of complexity and ambivalence). Conclusion: The willingness to donate organs is closely related to spirituality. By understanding the spirituality of this group, it is possible to take an important step in promoting the development of organ donation. [ABSTRACT FROM AUTHOR]

Pseudosasa subsolida belongs to the Pseudosasa genus within the Poaceae family. Due to its unique flowering cycle and the physiological traits associated with asexual reproduction, acquiring floral material from P. subsolida is particularly challenging. To investigate the causes of the low seed set rate in P. subsolida, floral organs and the development of male and female gametes were examined using conventional paraffin sectioning. The results revealed that the spikelet of P. subsolida exhibited the characteristics of a pseudospikelet with a latent bud, while the inflorescence displayed traits of an infinite inflorescence. Each spikelet contained approximately 10–16 florets and was accompanied by two bracts at its base. The fundamental structure of the florets comprised one lemma, one palea, three lodicules, three stamens, and one pistil. At the later stages of anther development, some abnormalities were observed, including the failure of pollen grains to form, deformation and shrinkage of the cells in the anther sac and tapetum, loss of the cells in the middle layer, cavitation of the microspores, and no identifiable contents The study concluded that the primary factor contributing to the low seed setting rate of P. subsolida was the aberrant development of male gametophytes. The significance of this study lay in its pioneering exploration of the reproductive structure of P. subsolida, and provide a theoretical reference for the fundamental examination of flower structure. [ABSTRACT FROM AUTHOR]

BACKGROUND: Distiller's grains are a by‐product of liquor production with a higher yield than liquor. Developing and utilizing distiller's grains well could alleviate the problem of scarce feed resources. Our present experiment was conducted with 6000 yellow‐feathered broilers to study the effects of adding distiller's grains yeast cultures (DGYC) to the diet on growth performance and immunity of broilers. The broilers were divided into five groups, receiving different DGYC concentrations during two stages. Growth performance, intestinal microorganisms and immune organ development were measured. RESULTS: The results showed that groups B and D, supplemented with medium and high concentrations of DGYC, respectively, had significantly improved growth performance compared to the control group (P < 0.05). Group D also showed higher immune organ index (P < 0.01), increased serum total protein, high‐density lipoprotein and immunoglobulin levels (P < 0.05) and lower levels of low‐density lipoprotein, triglycerides, interleukin 1β and tumor necrosis factor α (P < 0.05). Hematoxylin and eosin staining confirmed improved immune organ development in group D (P < 0.05). Furthermore, in high‐concentration group D, levels of short‐chain fatty acids (SCFA; acetic, propionic and butyric acids) in cecal chyme were significantly increased (P < 0.05). The richness (Chao1) and diversity (Faith‐pd) index of cecal microbiota were significantly higher in group D compared to the control group (P < 0.05). The microbial composition in group D differed from the control and medium‐concentration group B. Seven bacteria (Clostridia‐UCG‐014, UCG‐009, DTU089, UCG‐010, Campylobacter, Harryflintia, Shuttleworthia) showed significant differences (P < 0.05). After DGYC feeding, DTU089 decreased, while other SCFA‐producing bacteria increased (P < 0.05). Subsequently, KEGG function and corresponding signal pathway predictions were performed on bacteria with significant differences. Group D exhibited a higher enrichment of immune function pathways (P < 0.01) and showed significant changes in four immune signaling pathways according to the signal pathway heatmap. CONCLUSION: Our data suggest that high concentrations of DGYC can be applied as a feed additive for broilers that promotes growth, improves intestinal health and enhances certain immunity. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Calcium (Ca2+) is a universal signaling cation with a prominent role as second messenger in many different plant processes, including sexual reproduction. However, there is much less knowledge about the involvement of Ca2+ during in vitro embryogenesis processes. In this work we performed a study of Ca2+ levels during the different stages of microspore embryogenesis in Brassica napus , with special attention to how Ca2+ can influence the occurrence of different embryogenic structures with different embryogenic potential. We also performed a pharmacological study to modulate Ca2+ homeostasis during different stages of the process, using a series of Ca2+-altering chemicals (BAPTA-AM, bepridil, chlorpromazine, cyclopiazonic acid, EGTA, inositol 1,4,5-trisphosphate, ionophore A23187, W-7). This study shows that Ca2+ increase can be considered as an early marker of induction of microspore embryogenesis. Besides, Ca2+ levels are highly dynamic during microspore embryogenesis, influencing the final embryo yield. Increase of either extracellular or intracellular Ca2+ levels improves embryo yield without altering the proportion of highly embryogenic structures formed, which suggests that elevated Ca2+ levels increase the amount of microspores reaching the minimum Ca2+ threshold required for embryogenesis induction. Conversely, inhibition of Ca2+ uptake or signaling results in reduced embryogenic response. This allows to modulate embryo yield within a functional range, with lower and upper Ca2+ thresholds beyond which embryo yield is reduced. There seems to be a relationship between Ca2+ levels and embryo differentiation. [ABSTRACT FROM AUTHOR]

Macrophages are known to support cardiac development and homeostasis, contributing to tissue remodeling and repair in the adult heart. However, it remains unclear whether embryonic macrophages also respond to abnormalities in the developing heart. Previously, we reported that the structural protein Sorbs2 promotes the development of the second heart field, with its deficiency resulting in atrial septal defects (ASD). In analyzing RNA-seq data, we noted an upregulation of macrophage-related genes in Sorbs2 −/− hearts. Immunostaining and lineage-tracing confirmed an increase in macrophage numbers, underscoring a macrophage response to myocardial abnormalities. Partial depletion of macrophages led to downregulation of genes involved in lipid metabolism, muscle development and organ regeneration, alongside upregulation of genes associated with DNA damage-induced senescence and cardiomyopathy. Additionally, a non-significant increase in septal defects in macrophage-depleted Sorbs2 −/− hearts suggests a potential reparative function for macrophages in maintaining structural integrity. Valve formation, however, remained unaffected. Our findings suggest that embryonic macrophages might sense abnormalities in embryonic cardiomyocytes and could adaptively support cardiac structure and function development in response to myocardial abnormalities. [ABSTRACT FROM AUTHOR]

The evolutionary origin of the vertebrate brain remains a major subject of debate, as its development from a dorsal tubular neuroepithelium is unique to chordates. To shed light on the evolutionary emergence of the vertebrate brain, we compared anterior neuroectoderm development across deuterostome species, using available single-cell datasets from sea urchin, amphioxus, and zebrafish embryos. We identified a conserved gene co-expression module, comparable to the anterior gene regulatory network (aGRN) controlling apical organ development in ambulacrarians, and spatially mapped it by multiplexed in situ hybridization to the developing retina and hypothalamus of chordates. Using functional approaches, we show Wnt signaling regulating this co-expression module in amphioxus, like the aGRN in echinoderms, and that its overactivation suppresses forebrain identity. This suggests a previously undescribed role for Wnt signaling in amphioxus in determining the position of the forebrain. We propose this Wnt-regulated gene co-expression module as a possible mechanism by which the brain set antero-dorsally early in chordate evolution. [ABSTRACT FROM AUTHOR]

Recent advances in bioengineering have made it possible to develop increasingly complex biological systems to recapitulate organ functions as closely as possible in vitro. Monitoring the assembly and growth of multi-cellular aggregates, micro-tissues or organoids and extracting quantitative information is a crucial but challenging task required to decipher the underlying morphogenetic mechanisms. We present here an imaging platform designed to be accommodated inside an incubator which provides high-throughput monitoring of cell assemblies over days and weeks. We exemplify the capabilities of our system by investigating human induced pluripotent stem cells (hiPSCs) enclosed in spherical capsules, hiPSCs in tubular capsules and yeast cells in spherical capsules. Combined with a customized pipeline of image analysis, our solution provides insight into the impact of confinement on the morphogenesis of these self-organized systems. [ABSTRACT FROM AUTHOR]

Background: Paeonia section Moutan DC. is a significant perennial subshrub, the ornamental value of which heavily depends on the type of flower it possesses. MADS-box transcription factors have a particular impact on the intricate process of floral organ development and differentiation. The release of the whole-genome data from Paeonia ostii now allows us to conduct a thorough investigation of the tree peony MADS-box gene family. Results: In this study, we identified 110 MADS-box genes in Paeonia ostii that were classified into 5 subgroups. Gene structure, domain and motif analyses revealed the conservation of the structure of these subgroups. Analysis of the cis-acting elements revealed that the 110 PoMADS genes contained different kinds of hormones and stress-related cis-acting elements in their promoter regions. Quantitative real-time PCR analysis was employed to validate the expression patterns of some PoMADS genes related to floral organ development. Genome collinearity analysis with Arabidopsis and grape revealed the conservation of PoMADS genes during evolution. A total of 857 SSRs were identified by analysing the genome sequences of identified genes. We additionally created protein‒protein interaction networks for PoMADS proteins and analysed proteins that could interact among PoMADSs in Arabidopsis thaliana and grape. Conclusion: These findings offer fundamental insights for understanding the function of the MADS-box gene family, which can aid in the selection and breeding of tree peony varieties with high ornamental value in addition to supporting the understanding of the process of tree peony floral organogenesis. [ABSTRACT FROM AUTHOR]

Hydra regenerates one head when cut, but how forces shaping the head are coordinated remains unclear. Soft compression of Hydra's head-regenerating tissues induces the formation of viable, two-headed animals. Compression creates new topological defects in the supracellular orientational order of muscular actin fibers, associated with additional heads. Theory supports that these defects organize muscle stresses required to shape the head. By compressing head-regenerating tissues along their body axis, we formed toroidal tissues, whose unique topology allows for the absence of defects. Toroids with no actin defects did not regenerate. Toroids with actin defects regenerated into viable toroidal animals with a bifurcated body. Topological defects in the actin orientational order are thus necessary for complete regeneration of Hydra, defining actin topological defects as mechanical organizers of morphogenesis. [ABSTRACT FROM AUTHOR]

Many bacteria live in polymeric fluids, such as mucus, environmental polysaccharides, and extracellular polymers in biofilms. However, laboratory studies typically focus on cells in polymer-free fluids. Here, we show that interactions with polymers shape a fundamental feature of bacterial life--how they proliferate in space in multicellular colonies. Using experiments, we find that when polymer is sufficiently concentrated, cells generically and reversibly form large serpentine "cables" as they proliferate. By combining experiments with biophysical theory and simulations, we demonstrate that this distinctive form of colony morphogenesis arises from an interplay between polymer-induced entropic attraction between neighboring cells and their hindered ability to diffusely separate from each other in a viscous polymer solution. Our work thus reveals a pivotal role of polymers in sculpting proliferating bacterial colonies, with implications for how they interact with hosts and with the natural environment, and uncovers quantitative principles governing colony morphogenesis in such complex environments. [ABSTRACT FROM AUTHOR]

Summary: The sexual reproductive organs of bryophytes – in which gametes necessary for fertilization are produced, namely, male antheridia and female archegonia – are formed from vegetative haploid gametophytes. In dioicous bryophytes such as Marchantia polymorpha, the genes within the sex‐determining regions in distinct sexual strains have been identified. However, in monoicous bryophytes such as Physcomitrium patens, how the two sex fates are specified on the same gametophyte remained unknown.Here, we identified an RWP‐RK domain‐containing transcription factor in P. patens, PpRKD, as a factor required for the development of female organs, based on the absence of archegonia in loss‐of‐function Pprkd mutants and the specific expression of PpRKD in archegonia.When ectopically induced, the expression of PpRKD resulted in the repression of antheridial development and the emergence of archegonium‐like organs. Furthermore, the young primordia inside the antheridial bundle displayed typical archegonial division patterns, suggesting that PpRKD confer female fate to antheridium primordia.This study represents the first instance where the function of sex determination has been identified among RKD orthologs in land plants. This finding should provide a new framework for the molecular evolutionary context of the genes in the RKD family, considering the recent elucidation of their roles in algae. [ABSTRACT FROM AUTHOR]