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The Chub mackerel, Scomber japonicus, is one of the most important species in the fisheries industry. Seedling production is required to reinforce the natural resource and for aquaculture. For the establishment of mass seedling production techniques, it is necessary to develop breeding and rearing technologies on the basis of information on development during the early life stages.1. Development of the digestive system was studied in larval and juvenile Chub mackerel under rearing conditions. The minimum necessary organs such as the liver, gall bladder, and pancreas were formed during the yolk-sac larval stage. Feeding was observed from two days after hatching. At the preflexion stage (within 5 days after hatching), the rotation of the intestine has been confirmed. At the beginning of the flexion stage (6 to 8 days after hatching), pharyngeal teeth were found, and the gastric gland and spleen were differentiated. At the onset of the postflexion stage (9 to 13 days after hatching), the pyloric caeca began to form. By the end of the postflexion stage, almost all differentiation of the digestive organs had been completed. The functions of the stomach and pyloric caeca developed from the postflexion stage to the transitional period to the juvenile. The formation of the digestive system occurred in the early developmental stages and it might contribute to the rapid growth in the larval stage.2. The previous research has not fully clarified the transitional periods from juvenile to young and from young to immature fish in fish development. These transitional periods may require further study for better understanding in the physiological and behavioral changes that occur during these development stages. Therefore, we investigated the relative growth of length in various parts of the fish body and the shape and size of the fins to examine the morphological characteristics, as well as behavioral characteristics. The relative growth of total length (TL), body length (BL), preanal length (PL), body height (BH), head length (HL), head height (HH), snout length (SnL), eye diameter (ED), caudal peduncle depth (CPD) and upper jaw length (UJL) was determined by analyzing 477 fish ranging from 3.1 to 90.9 mm BL. Almost every part of the body had an inflection point of growth at a BL of 6 to 8 mm, which marks the transitional stage from flexion to postflexion. When comparing the morphological traits of each body part against BL from 3.1 to 90.9 mm with those of adults (319.7 to 338.3 mm BL), all ratios against BL exhibited a notable increase from 10 to 15 mm, which corresponds to the transitional stage to juveniles. Afterward, the ratios of TL, UJL, CPD, BH, HH, and ED decreased towards 50 mm BL, and these rations reached those of adults at a size of 90 mm BL. These lengths and ratios exhibited significant changes at the sizes of 50 and 90 mm BL. Fin shape and size were determined by measuring 274 fish ranging from 24.1 to 338.3 mm BL. The fin shapes of the first dorsal fin, second dorsal fin, pelvic fin, pectoral fin, and anal fin were determined by the ratios of fin length to fin base length. The shape of the caudal fin was determined by the aspect ratio (AR) of the fin and the caudal fin shape index (Wc). AR was calculated using the equation AR = Ic2/Sc, where lc represents the height of the caudal fin, and Sc represents the area of the caudal fin. The caudal fin shape index (Wc) was calculated using the equation Wc = A/A + B/A + C/A, where A, B, and C were defined as follows: In the caudal fin, the point farthest from the midline of the fish in the upward and downward directions were defined as X and Y, respectively. The fish body was then divided into the proximal region (A) and distal region (B) by a straight line connecting these two points. The concave portion within region A was defined as region C. Fin sizes were determined by calculating the ratio of fin area to body length squared. The shapes of the fins, except for the caudal fin, did not show significant changes within the measured range. AR and Wc increased and decreased, respectively, with development up to 200 mm BL, which suggested that the fin of mackerel became more suitable for cruising swimming as they grew. Fin area ratios of the second dorsal, pectoral, and caudal fins decreased up to 100 mm BL, after which the ratios of the pectoral and caudal fins reached those of adults. The fin area ratio of the first dorsal fin increased with development, while the ratio of the pelvic fin remained constant. The finlet fin area ratio, on the other hand, decreased with development. Based on these findings, it can be concluded that the sizes of most fins of mackerel changed up to 100 mm BL, after which they reached the sizes of adults. Furthermore, the shape of the caudal fin changed to become more suitable for cruising swimming with development up to 200 mm BL. Based on Fukui's (2020) definitions, it can be inferred that the relative growth of length, fin shape, and size can be used to identify the developmental stages of post-larval bony fishes. Specifically, a size range of 50-100 mm BL would indicate the young stage, where morphological characteristics of the adult stage are present but body proportions are not yet fully developed. On the other hand, a size range over 100 mm BL would indicate the immature stage, where morphological characteristics of the adult stage are fully developed but the fish is still sexually immature, and its reproductive capacity is not fully developed.3. The effects of photoperiod and water temperature on swim bladder inflation were studied specifically for healthy fish larvae. To investigate the relationship between photoperiod and the timing of swim bladder inflation, the fish were subjected to five different photoperiod treatments: constant-dark (0L:24D), 9 hours of light, and 15 hours of dark (9L:15D), 12 hours of light and 12 hours of dark (12L:12D), 17 hours of light and 7 hours of dark (17L:7D), and constant-light (24L:0D). The initial swim bladder inflation was observed 62-64 hours after hatching for all photoperiod treatments except for the constant-dark, and its ratios were 30 to 40%, respectively. The timing of the initial swim bladder inflation was noted to correspond to the first period of darkness after mouth opening. In the constant-light treatment, the initial swim bladder inflation was also observed at the same time, which suggested that it might have been driven by an endogenous rhythm. In contrast, in the constant-dark treatment, swim bladder inflation and feeding were not observed. After the initial inflation, the swim bladder was observed to deflate in the presence of light, and then inflated again in dark conditions. The ratios of swim bladder inflation at 90 to 94 hours after hatching were 80 to 90% at 9L, 12L, and 17L; however, at 24L, the ratio was about 50%. The total lengths of fish at 0L, 9L, 12L, 17L, and 24L were 43.8 ± 0.2 mm, 4.0 ± 0.2 mm, 4.2 ± 0.2 mm, 4.2 ± 0.2 mm, and 4.5 ± 0.2 mm, respectively. The total length of fish at 9L and 0L were significantly smaller than those at other photoperiods. To determine the effect of temperature on the initial swim bladder inflation, the fish were subjected to three different temperatures (18°C, 21°C, and 24°C) under a photoperiod of 16 hours of light and 8 hours of darkness. The initial swim bladder inflations were observed at 112, 64, and 64 hours after hatching and the ratios were 53.3, 50.0, and 86.7% at 18°C, 21°C, and 24°C, respectively. The total length of fish at the 18°C treatment was significantly larger than those at the other temperatures. These data indicate that a high swim bladder inflation ratio requires a dark period and a higher temperature within the appropriate range.4. In order to obtain basic knowledge on rearing conditions, ontogenetic changes in the oxygen consumption of mackerel were investigated from the egg stage to 30 days after hatching, under resting conditions and at a temperature of 21°C. During the egg stage, the oxygen consumption of each egg slightly increased from morula to the appearance of the embryo, ranging from 0.19×103 to 0.34×103 μℓ/min. There was a significant increase in the oxygen consumption of the developing embryo, specifically from the appearance of Kupffer's vesicle to just before hatching. During this period, the oxygen consumption ranged from 0.5 ± 0.06 × 103 to 1.43 ± 0.35 × 103 μL/min. In the egg stage, the oxygen consumption of mackerel was 1.5 to 2 times higher than that of red sea bream, and 0.4 to 0.6 times that of the Pacific Bluefin tuna (PBT). After hatching, oxygen consumption can be expressed by the following equation: M = aWb, where M is the oxygen consumption of individual fish, W is the body mass, and a and b are constants. The relationship between oxygen consumption and body mass can also be expressed as M/W = aWb-1. M and M/W had a double phasic relationship with W. The first regression point at 0.45 mg marks the phase when the fish begins to feed and transition to external nutrition. The second regression point at 12 mg marks the postflexion stage. At the transitional stage from larvae to juvenile, the body mass to body length ratio (M/W) of mackerel and PBT was almost the same. These data suggested that both mackerel and PBT require high levels of oxygen to support their growth and development from the egg to the juvenile stage.5. Fish that rely on visual cues for feeding generally exhibits a circadian rhythm and are known to consume more food during certain times of the day. This feeding rhythm can vary depending on the fish species, size, time of day, and light intensity resulting in a unique pattern of feeding behavior specific to mackerel and their developmental stage. Understanding the feeding rhythm of fish is important for aquaculture professionals as it can help optimize feeding schedules and improve the growth and overall health of the fish. The feeding rhythms of the mackerel were assessed at 4, 10, 14, and 18 days after hatching, while exposed to a light cycle of 14 hours of light and 10 hours of darkness. The assessment was made by counting the number of rotifers and artemia presented in the gastrointestinal tract. On the 4th day after hatching, approximately 10 rotifers were fed to the fish immediately after the light period. During the day, there were approximately 25 rotifers present in the fish's gastrointestinal tract. However, in the evening, the number of rotifers increased significantly to about 100. During the dark period, the fish did not feed at all. On the 10th day after hatching, the fish also began feeding and consumed approximately 250 rotifers just after the transition to the light period. During the day, the fish maintained about 75 rotifers in their gastrointestinal tract. In the evening, the number of rotifers consumed increased again to about 250. On the 14th day after hatching, the fish were fed both rotifer and Artemia, but rotifers were not fed in the morning. The number of Artemia in the fish's gastrointestinal tract was maintained between 50 to 100 during the day, but in the evening, it significantly increased to over 250. On the 18th day after hatching, only Artemia was fed to the fish, and rotifers were not included in their diet. The number of Artemia observed in the fish's gastrointestinal tract was 480 individuals during the day, and it increased to over 500 in the evening. These data suggested that the larvae and juvenile mackerel have a feeding rhythm that was linked to the light-dark cycle, and they tended to consume the most food during the evening period. As the mackerel developed into juveniles, they stopped feeding on rotifers and switched to a diet of Artemia. Four different photoperiods (9L, 14L, 18L, and 24L) were studied to determine their impact on the survival, growth, and feeding of organisms, which was estimated using Elliott and Persson's equation at four-time points after hatching: 4, 8, 12, and 16 days. At the end of the experiment (17 days after hatching), the total length exposed to 9L, 14L, 18L, and 24L photoperiods were 7.6 ± 1.7, 15.6 ± 4.3, 21.8 ± 2.5, and 21.7 ± 3.0 mm, respectively. The total length exposed to 18L and 24L photoperiods were significantly greater than that of the other treatments. The survival ratios were 20.2 ± 2.1%, 23.9 ± 8.6%, 38.4 ± 2.3%, and 49.4 ± 11.0% for the 9L, 14L, 18L, and 24L photoperiods, respectively. The survival ratio was observed to increase with longer photoperiods. The estimated feeding amount per organism per day on day 4 after hatching was 0.4, 0.5, 0.6, and 0.7 mg for the 9L, 14L, 18L, and 24L treatments, respectively. On day 8 after hatching, the estimated feeding amount increased to 1.0, 1.4, 2.0, and 1.2 mg, with the 18L treatment showing the highest amount and the 9L treatment showing the lowest. On day 12 after hatching, the feeding amounts were 4.3, 25.9, 33.9, and 32.0 mg for the 9L, 14L, 18L, and 24L treatments, respectively, with the 18L treatment having the highest amount and the 9L treatment having the lowest, as on day 8. On day 16 after hatching, the feeding amounts were 17.2, 85.0, 126.3, and 101.9 mg for the 9L, 14L, 18L, and 24L treatments, respectively, with the 18L treatment having the highest amount and the 9L treatment having the lowest, as on day 8 and day 12. The results showed that the 24L and 18L photoperiods had better growth and survival rates. The feeding amount was found to be highest in the 24L photoperiod at 4 days after hatching but then increased in the 18L photoperiod thereafter.6. In this study, it was found that the mackerel underwent a transition to the juvenile period around 15 days after hatching (at around 15 mm BL), to the young fish period around 21 days after hatching (at around 50 mm BL), to the immature stage around 30 days after hatching (at around 90-100 mm BL), and to the adult period after exceeding 220 mm BL. It was also found that the first opening of the swim bladder occurred on the night of the third day after hatching (around 90 hours after hatching), and constant light conditions were beneficial for growth but dark periods were necessary to improve swim bladder inflation. Moreover, it was also found that the advantage of constant light conditions was lost in the postflexion stage due to increased basal metabolism, and a long-day photoperiod with a light-dark cycle was effective for feeding by visual cues.

The liver kinase B1 (LKB1) controls cellular metabolism and cell polarity across species. We previously established a mechanism for negative regulation of transforming growth factor β (TGFβ) signaling by LKB1. The impact of this mechanism in the context of epithelial polarity and morphogenesis remains unknown. After demonstrating that human mammary tissue expresses robust LKB1 protein levels, whereas invasive breast cancer exhibits significantly reduced LKB1 levels, we focused on mammary morphogenesis studies in three dimensional (3D) acinar organoids. CRISPR/Cas9-introduced loss-of-function mutations of STK11 (LKB1) led to profound defects in the formation of 3D organoids, resulting in amorphous outgrowth and loss of rotation of young organoids embedded in matrigel. This defect was associated with an enhanced signaling by TGFβ, including TGFβ auto-induction and induction of transcription factors that mediate epithelial-mesenchymal transition (EMT). Protein marker analysis confirmed a more efficient EMT response to TGFβ signaling in LKB1 knockout cells. Accordingly, chemical inhibition of the TGFβ type I receptor kinase largely restored the morphogenetic defect of LKB1 knockout cells. Similarly, chemical inhibition of the bone morphogenetic protein pathway or the TANK-binding kinase 1, or genetic silencing of the EMT factor SNAI1, partially restored the LKB1 knockout defect. Thus, LKB1 sustains mammary epithelial morphogenesis by limiting pathways that promote EMT. The observed downregulation of LKB1 expression in breast cancer is therefore predicted to associate with enhanced EMT induced by SNAI1 and TGFβ family members.

A combination of in toto imaging and theory suggests a new mechanism for the remodeling of veins in vascular networks.

ABSRACT The cerebellum has a simple cytoarchitecture consisting of a folded cortex with three cell layers that surrounds a nuclear structure housing the output neurons. The excitatory neurons are generated from a unique progenitor zone, the rhombic lip, whereas the inhibitory neurons and astrocytes are generated from the ventricular zone. The growth phase of the cerebellum is driven by lineage-restricted progenitor populations derived from each zone. Research during the past decade has uncovered the importance of cell-to-cell communication between the lineages through largely unknown signaling mechanisms for regulating the scaling of cell numbers and cell plasticity during mouse development and following injury in the neonatal (P0-P14) cerebellum. This Review focuses on how the interplay between cell types is key to morphogenesis, production of robust neural circuits and replenishment of cells after injury, and ends with a discussion of the implications of the greater complexity of the human cerebellar progenitor zones for development and disease.

Background: Yerba-mate (Ilex paraguariensis) is a perennial native tree from South America. Improper management of yerba-mate crops results in low yield. This work evaluated the recovery and the vegetative capacity of the crop after coppicing. Methods: A 2-year field observation approach was used and the study area was monitored from 2019 to 2021 in a 20-year-old yerba-mate crop with low yield. Drastic coppicing was used as a strategy, aiming to study the effect of the month and the height of pruning. Four groups were defined combining the trunk heights of 10 and 40 cm and the months of pruning June and August. Results: Yerba-mate plants showed a low mortality rate of 2%. In the first year after the intervention, the height of the cutting was the most important factor that influenced the amount of primary and secondary branches, validating response surfaces with r2 values of 0.9942 and 0.9084, respectively. In the second year of the experiment, full recovery in productivity was reached, with a mean rise of 109.7% in the plants of the group coppiced in June 40 cm above the soil. Conclusion: The techniques used in this study are appropriate for vigor recovery in yerba-mate plants inadequately managed and allow a new architecture on plants, enabling mechanical harvesting.

Rete ridges (RRs) are distinct undulating microstructures at the junction of the dermis and epidermis in the skin of humans and certain animals. This structure is essential for enhancing the mechanical characteristics of skin and preserving homeostasis. With the development of tissue engineering and regenerative medicine, artificial skin grafts have made great progress in the field of skin healing. However, the restoration of RRs has been often disregarded or absent in artificial skin grafts, which potentially compromise the efficacy of tissue repair and regeneration. Therefore, this review collates recent research advances in understanding the structural features, function, morphogenesis, influencing factors, and reconstruction strategies pertaining to RRs. In addition, the preparation methods and limitations of tissue-engineered skin with RRs are discussed. STATEMENT OF SIGNIFICANCE: The technology for the development of tissue-engineered skin (TES) is widely studied and reported; however, the preparation of TES containing rete ridges (RRs) is often ignored, with no literature reviews on the structural reconstruction of RRs. This review focuses on the progress pertaining to RRs and focuses on the reconstruction methods for RRs. In addition, it discusses the limitations of existing reconstruction methods. Therefore, this review could be a valuable reference for transferring TES with RR structure from the laboratory to clinical applications in skin repair.

Cells with subcellular lumens form some of the most miniature tubes in the tubular organs of animals. These are often crucial components of the system, executing functions at remote body locations. Unlike tubes formed by intercellular or autocellular junctions, the cells with junctionless subcellular lumens face unique challenges in modifying the cell shape and plasma membrane organization to incorporate a membrane-bound tube within, often associated with dramatic cellular growth and extensions. Results in the recent years have shown that membrane dynamics, including both the primary delivery and recycling, is crucial in providing the cell with the flexibility to face these challenges. A significant portion of this information has come from two in vivo invertebrate models; the Drosophila tracheal terminal cells and the C. elegans excretory cell. This review focuses on the data obtained from these systems in the recent past about how trafficking pathways influence subcellular tube and branching morphogenesis. Given that such tubes occur in vertebrate vasculature, these insights are relevant to human health, and we contrast our conclusions with the less understood subcellular tubes of angiogenesis.

Annelid chaetae are extracellular chitinous structures that are formed in an extracellular epidermal invagination, the chaetal follicle. The basalmost cell of this follicle, the chaetoblast, serves like a 3D-printer as it dynamically shapes the chaeta. During chaetogenesis apical microvilli of the chaetoblast form the template for the chaeta, any structural details result from modulating the microvilli pattern. This study describes this process in detail in the model organism Platynereis dumerilii and clarifies some aspects of chaetogenesis in its close relative Nereis vexillosa, the first annelid in which the ultrastructure of chaetogenesis had been described. Nereid species possess compound chaetae characteristic for numerous subgroups of errant annelids. The distal most section of these chaetae is movable; a hinge connects this part of the chaeta to the shaft. Modulation of the microvilli and differences in their structure, diameter and number of microvilli, and their withdrawal and reappearance determine the shape of these compound chaetae. Chaetal structure and pattern also change during life history. While larvae possess a single type of chaeta (in addition to internal aciculae), juveniles and adults possess two types of chaetae that are replaced by large paddle-shaped chaetae in swimming epitokous stages. Chaetogenesis is a continuous process that lasts during the entire lifespan. The detailed developmental sequence of chaetae and their site of formation are very similar within species and species groups. We expect that similarity results from a conserved gene regulatory network making this an optimal system to test the phylogenetic affinity of taxa and the homology of their chaetae.

Sprouting angiogenesis, the formation of new vessels from preexisting vasculature, is an essential process in the regeneration of new tissues as well as in the development of some diseases like cancer. Although early studies identified chemical signaling as the main driver of this process, many recent studies have shown a strong role of mechanical signals in the formation of new capillaries. Different types of mechanical signals (e.g., external forces, cell traction forces, and blood flow-induced shear forces) have been shown to play distinct roles in the process; however, their interplay remains still largely unknown. During the last decades, mathematical and computational modeling approaches have been developed to investigate and better understand the mechanisms behind mechanically driven angiogenesis. In this manuscript, we review computational models of angiogenesis with a focus on models investigating the role of mechanics on the process. Our aim is not to provide a detailed review on model methodology but to describe what we have learnt from these models. We classify models according to the mechanical signals being investigated and describe how models have looked into their role on the angiogenic process. We show that a better understanding of the mechanobiology of the angiogenic process will require the development of computer models that incorporate the interactions between the multiple mechanical signals and their effect on cellular responses, since they all seem to play a key in sprout patterning. In the end, we describe some of the remaining challenges of computational modeling of angiogenesis and discuss potential avenues for future research.

Lumens, liquid-filled cavities surrounded by polarized tissue cells, are elementary units involved in the morphogenesis of organs. Theoretical modeling and computations, which can integrate various factors involved in biophysics of morphogenesis of cell assembly and lumens, may play significant roles to elucidate the mechanisms in formation of such complex tissue with lumens. However, up to present, it has not been documented well what computational approaches or frameworks can be applied for this purpose and how we can choose the appropriate approach for each problem. In this review, we report some typical lumen morphologies and basic mechanisms for the development of lumens, focusing on three keywords - mechanics, hydraulics and geometry - while outlining pros and cons of the current main computational strategies. We also describe brief guidance of readouts, i.e., what we should measure in experiments to make the comparison with the model's assumptions and predictions.

The Metazoan complexity arises from a primary building block, the epithelium, which comprises a layer of polarized cells that divide the organism into compartments. Most of these body compartments are organs formed by epithelial tubes that enclose an internal hollow space or lumen. Over the last decades, multiple studies have unmasked the paramount events required to form this lumen de novo. In epithelial cells, these events mainly involve recognizing external clues, establishing and maintaining apicobasal polarity, endo-lysosomal trafficking, and expanding the created lumen. Although canonical autophagy has been classically considered a catabolic process needed for cell survival, multiple studies have also emphasized its crucial role in epithelial polarity, morphogenesis and cellular homeostasis. Furthermore, non-canonical autophagy pathways have been recently discovered as atypical secretory routes. Both canonical and non-canonical pathways play essential roles in epithelial polarity and lumen formation. This review addresses how the molecular machinery for epithelial polarity and autophagy interplay in different processes and how autophagy functions influence lumenogenesis, emphasizing its role in the lumen formation key events.

Symbioses between legumes and rhizobia require establishment of the plant-derived symbiosome membrane, which surrounds the rhizobia and accommodates the symbionts by providing an interface for nutrient and signal exchange. The host cytoskeleton and endomembrane trafficking systems play central roles in the formation of a functional symbiotic interface for rhizobia endosymbiosis; however, the underlying mechanisms remain largely unknown. Here we demonstrate that the nodulation-specific kinesin-like calmodulin-binding protein (nKCBP), a plant-specific microtubule-based kinesin motor, controls central vacuole morphogenesis in symbiotic cells in Medicago truncatula. Phylogenetic analysis further indicated that nKCBP duplication occurs solely in legumes of the clade that form symbiosomes. Knockout of nKCBP results in central vacuole deficiency, defective symbiosomes and abolished nitrogen fixation. nKCBP decorates linear particles along microtubules, and crosslinks microtubules with the actin cytoskeleton, to control central vacuole formation by modulating vacuolar vesicle fusion in symbiotic cells. Together, our findings reveal that rhizobia co-opted nKCBP to achieve symbiotic interface formation by regulating cytoskeletal assembly and central vacuole morphogenesis during nodule development.

Starfish embryos derived from blastomeres separated at the early cleavage stage exhibit morphogenesis to form normally shaped, but smaller-sized dwarf bipinnaria larvae. To further understand this developmental capacity, we primarily characterized the morphogenetic processes of separated 2-cell and 4-cell stage blastomeres during the embryonic and larval periods of the starfish, Patiria Pectinifera. Using non-separated blastomeres as the control, we subjected the separated blastomeres to morphological analyses in conjunction with quantitative measurements of the changes in their body sizes with time post-fertilization. Our results were as follows: (i) Blastomeres separated at 2-cell and 4-cell stages synchronously developed into dwarf-sized bipinnaria larvae. (ii) Upon reaching a body size of 500-700 μm, all the bipinnaria larvae originating from the separated blastomeres and controls began to undergo a series of similar organ formation events in preparation for metamorphosis-recognized as the demarcation between the early and late substages of the bipinnaria larval period. (iii) The separated blastomeres became brachiolaria larvae capable of undergoing metamorphosis at differing rates after reaching approximately 1000-1200 μm body sizes, with adult rudiment and sensory organ forming functionally. (iv) The unfed controls and dwarf bipinnaria larvae derived from blastomeres separated at the 4-cell stage arrested their development synchronously without reaching the threshold size required for the latter half of the bipinnaria stage. These results, taken together, suggested that separated blastomeres possess the developmental capacity to become brachiolaria larvae through a shift in morphogenetic regulation from a synchronous growth to size adjustment during the larval period.

Insufficient vascularization is a recurring cause of impaired pedicled skin flap healing. The administration of adipose tissue-derived stromal cells' (ASCs') secretome is a novel approach to augment vascularization. Yet, the secretome comprised of soluble factors that require a sustained-release vehicle to increase residence time. We hypothesized that administration of a hydrogel derived from decellularized extracellular matrix (ECM) of porcine skin with bound trophic factors from ASCs enhances skin flap viability and wound repair in a rat model. Porcine skin was decellularized and pepsin-digested to form a hydrogel at 37°C. Conditioned medium (CMe) of human ASC was collected, concentrated 20-fold, and mixed with the hydrogel. Sixty Wistar rats were included. A dorsal skin flap (caudal based) of 3 × 10 cm was elevated for topical application of DMEM (group I), a prehydrogel with or without ASC CMe (groups II and III), or ASC CMe (group IV). After 7, 14, and 28 days, perfusion was measured, and skin flaps were harvested for wound healing assessment and immunohistochemical analysis. Decellularized skin ECM hydrogel contained negligible amounts of DNA (11.6 ± 0.6 ng/mg), was noncytotoxic and well tolerated by rats. Irrespective of ASC secretome, ECM hydrogel application resulted macroscopically and microscopically in similar dermal wound healing in terms of proliferation, immune response, and matrix remodeling as the control group. However, ASC CMe alone increased vessel density after 7 days. Porcine skin-derived ECM hydrogels loaded with ASC secretome are noncytotoxic but demand optimization to significantly augment wound healing of skin flaps.

During organismal development, organs and systems are built following a genetic blueprint that produces structures capable of performing specific physiological functions. Interestingly, we have learned that the physiological activities of developing tissues also contribute to their own morphogenesis. Specifically, physiological activities such as fluid secretion and cell contractility generate hydrostatic pressure that can act as a morphogenetic force. Here, we first review the role of hydrostatic pressure in tube formation during animal development and discuss mathematical models of lumen formation. We then illustrate specific roles of the notochord as a hydrostatic scaffold in anterior-posterior axis development in chordates. Finally, we cover some examples of how fluid flows influence morphogenetic processes in other developmental contexts. Understanding how fluid forces act during development will be key for uncovering the self-organizing principles that control morphogenesis.

Early cellular patterning is a critical step of embryonic development that determines the proper progression of morphogenesis in all metazoans. It relies on a series of rapid reductive divisions occurring simultaneously with the specification of the fate of different subsets of cells. Multiple species developmental strategies emerged in the form of a unique cleavage pattern with stereotyped division geometries. Cleavage geometries have long been associated to the emergence of canonical developmental features such as cell cycle asynchrony, zygotic genome activation and fate specification. Yet, the direct causal role of division positioning on blastomere cell behavior remain partially understood. Oriented and/or asymmetric divisions define blastomere cell sizes, contacts and positions, with potential immediate impact on cellular decisions, lineage specification and morphogenesis. Division positions also instruct daughter cells polarity, mechanics and geometries, thereby influencing subsequent division events, in an emergent interplay that may pattern early embryos independently of firm deterministic genetic programs. We here review the recent literature which helped to delineate mechanisms and functions of division positioning in early embryos.

Biological tubes serve as conduits through which gas, nutrients and other important fluids are delivered to tissues. Most biological tubes consist of multiple cells connected by epithelial junctions. Unlike these multicellular tubes, seamless tubes are unicellular and lack junctions. Seamless tubes are present in various organ systems, including the vertebrate vasculature, C.elegans excretory system, and Drosophila tracheal system. The Drosophila tracheal system is a network of air-filled tubes that delivers oxygen to all tissues. Specialized cells within the tracheal system, called terminal cells, branch extensively and form seamless tubes. Terminal tracheal tubes are polarized; the lumenal membrane has apical identity whereas the outer membrane exhibits basal characteristics. Although various aspects of membrane trafficking have been implicated in terminal cell morphogenesis, the precise secretory pathway requirements for basal and apical membrane growth have yet to be elucidated. In the present study, we demonstrate that anterograde trafficking, retrograde trafficking and Golgi-to-plasma membrane vesicle fusion are each required for the complex branched architecture of the terminal cell, but their inputs during seamless lumen formation are more varied. The COPII subunit, Sec31, and ER exit site protein, Sec16, are critical for subcellular tube architecture, whereas the SNARE proteins Syntaxin 5, Syntaxin 1 and Syntaxin 18 are more generally required for seamless tube growth and maintenance. These data suggest that distinct components of the secretory pathway have differential contributions to basal and apical membrane growth and maintenance during terminal cell morphogenesis.

In brief Trophectoderm is the first tissue to differentiate in the early mammalian embryo and is essential for hatching, implantation, and placentation. This review article discusses the roles of Ras homolog family members (RHO) and RHO-associated coiled-coil containing protein kinases (ROCK) in the molecular and cellular regulation of trophectoderm formation. Abstract The trophectoderm (TE) is the first tissue to differentiate during the preimplantation development of placental mammals. It constitutes the outer epithelial layer of the blastocyst and is responsible for hatching, uterine attachment, and placentation. Thus, its formation is the key initial step that enables the viviparity of mammals. Here, we first describe the general features of TE formation at the morphological and molecular levels. Prospective TE cells form an epithelial layer enclosing an expanding fluid-filled cavity by establishing the apical-basal cell polarity, intercellular junctions, microlumen, and osmotic gradient. A unique set of genes is expressed in TE that encode the transcription factors essential for the development of trophoblasts of the placenta upon implantation. TE-specific gene expressions are driven by the inhibition of HIPPO signaling, which is dependent on the prior establishment of the apical-basal polarity. We then discuss the specific roles of RHO and ROCK as essential regulators of TE formation. RHO and ROCK modulate the actomyosin cytoskeleton, apical-basal polarity, intercellular junctions, and HIPPO signaling, thereby orchestrating the epithelialization and gene expressions in TE. Knowledge of the molecular mechanisms underlying TE formation is crucial for assisted reproductive technologies in human and farm animals, as it provides foundation to help improve procedures for embryo handling and selection to achieve better reproductive outcomes.

The blastocoel is a fluid-filled cavity characteristic of animal embryos at the blastula stage. Its emergence is commonly described as the result of cleavage patterning, but this historical view conceals a large diversity of mechanisms and overlooks many unsolved questions from a biophysics perspective. In this review, we describe generic mechanisms for blastocoel morphogenesis, rooted in biological literature and simple physical principles. We propose novel directions of study and emphasize the importance to study blastocoel morphogenesis as an evolutionary and physical continuum., Comment: 26 pages, 6 figures, review

Two sets of teeth (diphyodonty) characterise extant mammals but not reptiles, as they generate many replacement sets (polyphyodonty). The transition in long-extinct species from many sets to only two has to date only been reported in Jurassic eucynodonts. Specimens of the Late Triassic brasilodontid eucynodont Brasilodon have provided anatomical and histological data from three lower jaws of different growth stages. These reveal ordered and timed replacement of deciduous by adult teeth. Therefore, this diphyodont dentition, as contemporary of the oldest known dinosaurs, shows that Brasilodon falls within a range of wide variations of typically mammalian, diphyodont dental patterns. Importantly, these three lower jaws represent distinct ontogenetic stages that reveal classic features for timed control of replacement, by the generation of only one replacement set of teeth. This data shows that the primary premolars reveal a temporal replacement pattern, importantly from directly below each tooth, by controlled regulation of tooth resorption and regeneration. The complexity of the adult prismatic enamel structure with a conspicuous intra-structural Schmelzmuster array suggests that, as in the case of extant mammals, this extinct species would have probably sustained higher metabolic rates than reptiles. Furthermore, in modern mammals, diphyodonty and prismatic enamel are inextricably linked, anatomically and physiologically, to a set of other traits including placentation, endothermy, fur, lactation and even parental care. Our analysis of the osteodental anatomy of Brasilodon pushes back the origin of diphyodonty and consequently, its related biological traits to the Norian (225.42 ± 0.37 myr), and around 25 myr after the End-Permian mass extinction event.

Cell migration is necessary for morphogenesis, tissue homeostasis, wound healing and immune response. It is also involved in diseases. In particular, cell migration is inherent in metastasis. Cells can migrate individually or in groups. To migrate efficiently, cells need to be able to organize into a leading front that protrudes by forming membrane extensions and a trailing edge that contracts. This organization is scaled up at the group level during collective cell movements. If a cell or a group of cells is unable to limit its leading edge and hence to restrict the formation of protrusions to the front, directional movements are impaired or abrogated. Here we summarize our current understanding of the mechanisms restricting protrusion formation in collective cell migration. We focus on three in vivo examples: the neural crest cell migration, the rotatory migration of follicle cells around the Drosophila egg chamber and the border cell migration during oogenesis.

RESUMEN El cambio de uso de la tierra por diversos factores socio-económicos, climáticos, tecnológicos y culturales han tenido como consecuencia en la provincia de San Luis (Argentina) la pérdida de diversidad biológica, fragmentación y destrucción de hábitat, comprometiendo la existencia de la flora nativa, como es el caso de Leptochloa crinita (Lag.) P.M. Peterson & N. Snow, una especie con buena aptitud forrajera del monte chaqueño. Bajo este contexto, el presente trabajo tuvo como objetivo aplicar biotécnicas como alternativas para una propagación apropiada de este acervo genético. Se evaluó la organogénesis y callogénesis in vitro de diferentes explantos con distintos reguladores de crecimiento en un medio nutritivo Murashige y Skoog. El tratamiento con 6 mg l-1 de 2,4-D estimuló la callogénesis, mientras que los tratamientos combinados de auxinas y citocininas presentaron las mayores tasas de morfogénesis. El desarrollo de esta biotécnica permite disponer de metodologías adecuadas para iniciar ensayos de conservación in vitro, análisis de la variabilidad genética e inicio de programas de domesticación y mejoramiento genético. ABSTRACT In San Luis (Argentina), land-use change due to a variety of socioeconomic, climatic, technological and cultural factors has caused the loss of biological diversity, fragmentation and habitat destruction, compromising the existence of native flora, such as in the case of Leptochloa crinita (Lag.) PM Peterson & N. Snow, a species with good forage aptitude from the Chaco forest. In this context, the present work aimed to apply biotechniques as an alternative for an appropriate propagation of this gene pool. In vitro organogenesis and callogenesis of several explants were evaluated with different growth regulators on a Murashige and Skoog nutrient medium. Treatment with 6 mg l-1 of 2,4-D stimulated callogenesis, while combined auxin and cytokinin treatments presented the highest rates of morphogenesis. The development of this biotechnique makes it possible to have adequate methodologies to initiate in vitro conservation trials, analysis of genetic variability and the initiation of domestication and breeding programs.

Recreating functional tissues through bioengineering strategies requires steering of complex cell fate decisions. Notch, a juxtacrine signaling pathway, regulates cell fate and controls cellular organization with local precision. The engineering-friendly characteristics of the Notch pathway provide handles for engineering tissue patterning and morphogenesis. We discuss the physiological significance and mechanisms of Notch signaling with an emphasis on its potential use for engineering complex tissues. We highlight the current state of the art of Notch activation and provide a view on the design aspects, opportunities, and challenges in modulating Notch for tissue-engineering strategies. We propose that finely tuned control of Notch contributes to the generation of tissues with accurate form and functionality.

Interaction of a tumor with its microenvironment is an emerging field of investigation, and the crosstalk between cancer cells and the extracellular matrix is of particular interest, since cancer patients with abundant and stiff extracellular matrices display a poorer prognosis. At the post-juvenile stage, the extracellular matrix plays predominantly a structural role by providing support to cells and tissues; however, during development, matrix proteins exert a plethora of diverse signals to guide the movement and determine the fate of pluripotent cells. Taking a closer look at the communication between the extracellular matrix and cells of a developing body may bring new insights into cancer biology and identify cancer weaknesses. This review discusses parallels between the extracellular matrix roles during development and tumor growth.

Vascular and neuronal networks represent important examples of body structures created by processes of branching morphogenesis. Migration to an appropriate target in both axons and blood vessels are mediated by chemo-repulsive and attractive signals and the proximity of nerves and blood vessels suggest that there may be a molecular crosstalk and common cues between nerves and blood vessels. Vascular endothelial growth factor (VEGF), a key angiogenetic factor, has direct effects on the nervous system in terms of axon outgrowth and survival. Conversely, nerve growth factor (NGF), a well-known neurotropic molecule, exhibits angiogenic properties. Available data on the morphogenesis of vascular and neuronal networks and on the relationships between their remodeling processes will be the focus of the present study.

Recreating functional tissues through bioengineering strategies requires steering of complex cell fate decisions. Notch, a juxtacrine signaling pathway, regulates cell fate and controls cellular organization with local precision. The engineering-friendly characteristics of the Notch pathway provide handles for engineering tissue patterning and morphogenesis. We discuss the physiological significance and mechanisms of Notch signaling with an emphasis on its potential use for engineering complex tissues. We highlight the current state of the art of Notch activation and provide a view on the design aspects, opportunities, and challenges in modulating Notch for tissue-engineering strategies. We propose that finely tuned control of Notch contributes to the generation of tissues with accurate form and functionality.

The morphogenesis and plasticity of dendritic spines are associated with synaptic strength, learning, and memory. Dendritic spines are highly compartmentalized structures, which makes proteins involved in cellular polarization and membrane compartmentalization likely candidates regulating their formation and maintenance. Indeed, recent studies suggest polarity proteins help form and maintain dendritic spines by compartmentalizing the spine neck and head. Here, we review emerging evidence that polarity proteins regulate dendritic spine plasticity and stability through the cytoskeleton, scaffolding molecules, and signaling molecules. We specifically analyze various polarity complexes known to contribute to different forms of cell polarization processes and examine the essential conceptual context linking these groups of polarity proteins to dendritic spine morphogenesis, plasticity, and cognitive functions.

International audience; Cell fragmentation is commonly observed in human preimplantation embryos and is associated with poor prognosis during assisted reproductive technology (ART) procedures. However, the mechanisms leading to cell fragmentation remain largely unknown. Here, light sheet microscopy imaging of mouse embryos reveals that inefficient chromosome separation due to spindle defects, caused by dysfunctional molecular motors Myo1c or dynein, leads to fragmentation during mitosis. Extended exposure of the cell cortex to chromosomes locally triggers actomyosin contractility and pinches off cell fragments. This process is reminiscent of meiosis, during which small GTPase-mediated signals from chromosomes coordinate polar body extrusion (PBE) by actomyosin contraction. By interfering with the signals driving PBE, we find that this meiotic signaling pathway remains active during cleavage stages and is both required and sufficient to trigger fragmentation. Together, we find that fragmentation happens in mitosis after ectopic activation of actomyosin contractility by signals emanating from DNA, similar to those observed during meiosis. Our study uncovers the mechanisms underlying fragmentation in preimplantation embryos and, more generally, offers insight into the regulation of mitosis during the maternal-zygotic transition.

Tooth agenesis is a common structural birth defect in humans that results from failure of morphogenesis during early tooth development. The homeobox transcription factor Msx1 and the canonical Wnt signaling pathway are essential for “bud to cap” morphogenesis and are causal factors for tooth agenesis. Our recent study suggested that Msx1 regulates Wnt signaling during early tooth development by suppressing the expression of Dkk2 and Sfrp2 in the tooth bud mesenchyme, and it demonstrated partial rescue of Msx1-deficient molar teeth by a combination of DKK inhibition and genetic inactivation of SFRPs. In this study, we found that Sostdc1/Wise, another secreted Wnt antagonist, is involved in regulating the odontogenic pathway downstream of Msx1. Whereas Sostdc1 expression in the developing tooth germ was not increased in Msx1−/− embryos, genetic inactivation of Sostdc1 rescued maxillary molar, but not mandibular molar, morphogenesis in Msx1−/− mice with full penetrance. Since the Msx1−/−; Sostdc1−/− embryos exhibited ectopic Dkk2 expression in the developing dental mesenchyme, similar to Msx1−/− embryos, we generated and analyzed tooth development in Msx1−/−; Dkk2−/− double and Msx1−/−; Dkk2−/−; Sostdc1−/− triple mutant mice. The Msx1−/−; Dkk2−/− double mutants showed rescued maxillary molar morphogenesis at high penetrance, with a small percentage also exhibiting mandibular molars that transitioned to the cap stage. Furthermore, tooth development was rescued in the maxillary and mandibular molars, with full penetrance, in the Msx1−/−; Dkk2−/−; Sostdc1−/− mice. Together, these data reveal 1) that a key role of Msx1 in driving tooth development through the bud-to-cap transition is to control the expression of Dkk2 and 2) that modulation of Wnt signaling activity by Dkk2 and Sostdc1 plays a crucial role in the Msx1-dependent odontogenic pathway during early tooth morphogenesis.

It has been a long-standing mystery how complex biological structures emerge from such seemingly uncoordinated building blocks as cells and tissues, in the presence of only minimal environmental guidance. In particular, unifying descriptions independent of microscopic details of a specific organism are rare. In recent years, hydrodynamics has successfully been applied to describe certain types living systems. The thesis is concerned with understanding different aspects of structure formation in active liquids and biological systems. In the first chapter we investigate the coarsening dynamics in the Toner-Tu theory and compare it with an experimental colloidal system. Afterwards, we investigate the effect of chirality in active nematics, with applications to biological tissues. In the last part we derive and study a model to explain geometric deformations due to the presence of activity. The resulting dynamics might be able to explain morphogenetic processes.

The mechanisms that regulate the patterning of branched epithelia remain a subject of long-standing debate. Recently, it has been proposed that the statistical organization of multiple ductal tissues can be explained through a local self-organizing principle based on the branching-annihilating random walk (BARW) in which proliferating tips drive a process of ductal elongation and stochastic bifurcation that terminates when tips encounter maturing ducts. Here, applied to mouse salivary gland, we show the BARW model struggles to explain the large-scale organization of tissue. Instead, we propose that the gland develops as a tip-driven branching-delayed random walk (BDRW). In this framework, a generalization of the BARW, tips inhibited through steric interaction with proximate ducts may continue their branching program as constraints become alleviated through the persistent expansion of the surrounding tissue. This inflationary BDRW model presents a general paradigm for branching morphogenesis when the ductal epithelium grows cooperatively with the domain into which it expands.

Embryonic tissues undergoing shape change draw mechanical input from extraembryonic substrates. In avian eggs, the early blastoderm disk is under the tension of the vitelline membrane (VM). Here we report that the chicken VM characteristically downregulates tension and stiffness to facilitate stage-specific embryo morphogenesis. Experimental relaxation of the VM early in development impairs blastoderm expansion, while maintaining VM tension in later stages resists the convergence of the posterior body causing stalled elongation, failure of neural tube closure, and axis rupture. Biochemical and structural analysis shows that VM weakening is associated with the reduction of outer-layer glycoprotein fibers, which is caused by an increasing albumen pH due to CO2 release from the egg. Our results identify a previously unrecognized potential cause of body axis defects through mis-regulation of extraembryonic tissue tension.

The fascinating patterns of collective motion created by autonomously driven particles have fuelled active-matter research for over two decades. So far, theoretical active-matter research has often focused on systems with a fixed number of particles. This constraint imposes strict limitations on what behaviours can and cannot emerge. However, a hallmark of life is the breaking of local cell number conservation by replication and death. Birth and death processes must be taken into account, for example, to predict the growth and evolution of a microbial biofilm, the expansion of a tumour, or the development from a fertilized egg into an embryo and beyond. In this Perspective, we argue that unique features emerge in these systems because proliferation represents a distinct form of activity: not only do the proliferating entities consume and dissipate energy, they also inject biomass and degrees of freedom capable of further self-proliferation, leading to myriad dynamic scenarios. Despite this complexity, a growing number of studies document common collective phenomena in various proliferating soft-matter systems. This generality leads us to propose proliferation as another direction of active-matter physics, worthy of a dedicated search for new dynamical universality classes. Conceptual challenges abound, from identifying control parameters and understanding large fluctuations and nonlinear feedback mechanisms to exploring the dynamics and limits of information flow in self-replicating systems. We believe that, by extending the rich conceptual framework developed for conventional active matter to proliferating active matter, researchers can have a profound impact on quantitative biology and reveal fascinating emergent physics along the way.

A combination of in toto imaging and theory suggests a new mechanism for the remodeling of veins in vascular networks.

Cet article s’intéresse aux incipits d'œuvres de fiction et au phénomène de l’entrée en fiction lors de la lecture. Il consiste en une exploration théorique avec pour fil rouge la métaphore de la faille. Rupture, discontinuité, fracture : ces termes correspondent aussi bien à la notion de faille qu’à celle de commencement. Le commencement est le lieu critique de l’apparition d’une forme discontinue qui rompt avec l’avant. Dans une œuvre de fiction, il est l’endroit d’une cassure arbitraire entre le blanc et le texte, entre le silence et le verbe, entre le monde ordinaire et le monde fictionnel. Cette cassure est également une zone d’échange et de compatibilité entre les deux espaces qu’elle sépare. En effet, le monde fictionnel se détache du monde ordinaire tout en se composant de façon mimétique de ses ingrédients ; les représentations naissent dans la cognition du lecteur par le réemploi de représentations des référents du monde ordinaire ; enfin, tout un ensemble de processus mentaux usuellement dévolus au traitement de contenus sérieux se trouvent détournés pour servir l’activité imaginative. Le début in medias res, en propulsant sans ménagement le lecteur au milieu des choses, assume et expose, plus que d’autres, la discontinuité qui accompagne l’apparition du monde fictionnel et le début du texte. On fait l’hypothèse que cette faille y est même exploitée afin de séduire le lecteur et d’accélérer son accès à un état d’immersion fictionnelle. This paper focuses on the opening sentence in literary fiction and on how a reader can become immersed in the fictional world. It consists of a theoretical exploration, using the metaphor of the fault line as a red thread. A crack, a break, a fracture – such terms fit when talking about fault lines, and they could be used to describe beginnings too. Beginnings are critical points whereby a shape may appear. For as far as fiction is concerned, beginnings are where an arbitrary break takes place between the whiteness of paper and text, between silence and speech, between the ordinary world and the fictional world. The first sentence is both a frontier and a transition zone, separating two spaces as much as it connects them: the fictional world drifts away from reality but mimics it and is made of the very same ingredients; the representations that are conjured up in the reader’s imagination borrow representational material used for the referents of the ordinary world; finally a whole set of mental processes originally designed for serious tasks turn out, upon the instructions of the text, to be diverted for the sake of imagination. In medias res beginnings, where the reader finds himself or herself thrown into the middle of things, show, more than other types of beginnings, the discontinuity that goes with the emergence of fiction and of text. My hypothesis is that these cracks are being used in order to lure the reader in and hasten his/her immersion into fiction.

Many internal organs in all animals are composed of epithelial tubes that are formed during development. Despite much research into their formation over the years, the gene programmes and morphogenetic effectors responsible for controlling the morphogenesis of tubes and their order of action is yet to be comprehensively assessed. To investigate this, I utilised a simple model of tubulogenesis found in the Drosophila melanogaster embryonic salivary gland. Once specified, two mirror-symmetric placodes internalise from a flat epithelium in a coordinated manner, form two narrow-lumen epithelial tubes on the inside and eventually fuse to form a Y-shaped organ. Salivary gland cells do not undergo cell death or division, instead only through changing their shape, size, and neighbours. The short time window of specification, small cell population, continual lineage of cells and the established spatial patterning of genes within the salivary gland primordium prior to morphogenesis makes the Drosophila melanogaster embryonic salivary gland an excellent candidate for single cell RNA sequencing to identify novel genes involved in the process of tube budding and to delineate their order of expression. In my PhD, I used a combinatorial method of strictly staged embryos, fluorophore driven embryo cell sorting and 10x chromium single cell sequencing, to generate two novel stage 11 Drosophila melanogaster embryonic single cell sequencing data sets: a general epidermal dataset and a salivary gland primordium enriched dataset. Both datasets cover identical developmental time points of salivary gland specification and early invagination, and provide insights into a lineage of cells never previously identified in existing single cell sequencing datasets. Differential expression analysis between datasets successfully identified genes previously implicated in salivary gland development, alongside many novel genes with unknown roles in the process. The analysis also identified a subset of genes actively excluded from the salivary gland primordium, behaviour previously only reported for the genes Sex combs reduced and homothorax involved in the earliest specification of the salivary gland primordium. The salivary gland enriched dataset successfully clustered secretory cells and duct cells separately. Validation of novel genes identified from this dataset by in-situ hybridisation unveiled novel gene expression patterns within the salivary gland primordium, a new collection of genes not under the control of secretory cell fate maintenance transcription factor forkhead, and evidence of upregulation of the protein secretory machinery far earlier than previously reported. Pseudotime analysis enabled the identification of temporally controlled expression of transcription factors and adhesion molecules in time with morphogenetic movement of the tissue.

The caudal fin of teleosts is characterized by dorsoventral symmetry. Despite this external morphology, the principal rays of this appendage connect to bones below the notochord, indicating the ventral (hypochordal) identity of this organ.Here, we report that this typical architecture of the caudal fin is not fully conserved in the platyfish (Xiphophorus maculatus) and the guppy (Poecilia reticulata), representatives of the Poeciliidae family. We show that in these species, 3-4 principal rays connect to bones above the notochord, suggesting an epichordal contribution. Consistently, as examined in platyfish, dorsal identity genes zic1/4 were highly expressed in these rays, providing molecular evidence of their epichordal origin. Developmental analysis revealed that the earliest rays above the notochord emerge at the 10-ray stage of fin morphogenesis. In contrast to zebrafish and medaka, platyfish and guppies display a mirrored shape of dorsal and ventral processes of the caudal endoskeleton. Our study suggests that an ancestral bauplan expanded in poeciliids by advancing its symmetrical pattern.The platyfish evolved a fin architecture with the epichordal origin of its upper principal rays and a high level of symmetry in the caudal endoskeleton. This innovative architecture highlights the adaptation of the teleost skeleton.

The influence of antigiberrelic preparations on morphogenesis and anatomical structure of a leaf apparatus was studied. It is found that treatment of white mustard plants with chlormequat chloride and follicle caused a decrease in linear size, stem thickening, increase in the number and area of leaves.The influence of growth inhibitors on the mesostructure of white mustard plant leaves (Sinapis alba L.) was investigated. The application of preparations on mustard plantations in the budding phase led to optimization of the leaf anatomical structure, a thickening of the assimilation parenchyma due to the growth of its cells was observed.Under the action of the preparations, the cell volume of the columnar parenchyma in the sample with chlormequat chloride application increased and now is * 2489.86 ± 120.66 μm3, with follicle -2295.36 ± 116.25 μm3, compared to the control sample, where the volume is 2038 ± 101, 92 μm3. At the same time, the cell linear sizes of spongy parenchyma in experimental variants increase. A more expressible effect was observed under the action of chlormequat chloride.Investigation of the effect of synthetic plant growth regulators on the respiratory tract of white mustard leaves reveals that the number of stomata increased in the number of treated plants. The number of stomata in the variant with chlormequat chloride is - 377.79 ± 10.78 μm3, using follicle is * 370.88 ± 12.24 μm3 compared to the control sample of 341.49 ± 12.23 μm3., Вивчали вплив антигіберелінових препаратів на морфогенез, та анатомічну будову листкового апарату. Встановлено, що обробка рослин гірчиці білої хлормекватхлоридом та фолікуром призводила до зменшення лінійних розмірів, потовщення стебла, збільшення кількості та площі листків.Вивчено вплив ріст гальмуючих препаратів на мезоструктуру листків рослин гірчиці білої (Sinapis alba L.). Застосування препаратів на насадженнях гірчиці у фазу бутонізації зумовило оптимізацію анатомічної будови листків, відбувалося потовщення асиміляційної паренхіми внаслідок розростання її клітин. За дії препаратів зростав об’єм клітин стовпчастої паренхіми у варіанті із застосуванням хлормекватхлориду становить – *2489,86±120,66 мкм3, фолікуру – 2295,36±116,25 мкм3, проти контролю, де об’єм – 2038±101,92 мкм3. Одночасно збільшуються лінійні розміри клітин губчастої паренхіми в дослідних варіантах. Більш виражений ефект спостерігали за дії хлормекватхлориду.Вивчення дії синтетичних регуляторів росту рослин на продиховий апарат листків гірчиці білої свідчать що у оброблених рослин збільшувалася кількість та площа продихів. Кількість продихів у варіанті із використанням хлормекватхлориду становить – *377,79±10,78, фолікуру *370,88±12,24 в порівнянні з контролем 341,49±12,23мкм3.

The vitamin A derivative all-trans retinoic acid (RA) regulates early stages of inner ear development. As the early disruption of the RA pathway results in profound mispatterning of the developing inner ear, this confounds analyses of specific roles in later stages. Therefore, we used the temporal-specific exposure of all-trans RA or diethylaminobenzaldehyde to evaluate RA functions in late otic development.Perturbing late RA signaling causes behavioral defects analogous to those expected in larvae suffering from vestibular dysfunction. These larvae also demonstrate malformations of the semi-circular canals, as visualized through (a) use of the transgenic strain nkhspdmc12a, a fluorescent reporter expressed in otic epithelium; and (b) injection of the fluorescent lipophilic dye DiI. We also noted the altered expression of genes encoding ECM proteins or modifying enzymes. Other malformations of the inner ear observed in our work include the loss or reduced size of the utricular and saccular otoliths, suggesting a role for RA in otolith maintenance.Our work has identified a previously undescribed late phase of RA activity in otic development, demonstrating that vestibular defects observed in human patients in relation to perturbed RA signaling are not solely due to its early disruption in otic development.

The adherens junction (AJ) is an actin filament-anchoring junction. It plays a central role in epithelial morphogenesis through cadherin-based recognition and adhesion among cells. The stability and plasticity of AJs are required for the morphogenesis. An actin-binding α-catenin is an essential component of the cadherin-catenin complex and functions as a tension transducer that changes its conformation and induces AJ development in response to tension. Despite much progress in understanding molecular mechanisms of tension sensitivity of α-catenin, its significance on epithelial morphogenesis is still unknown. Here we show that the tension sensitivity of α-catenin is essential for epithelial cells to form round spheroids through proper multicellular rearrangement. Using a novel in vitro suspension culture model, we found that epithelial cells form round spheroids even from rectangular-shaped cell masses with high aspect ratios without using high tension and that increased tension sensitivity of α-catenin affected this morphogenesis. Analyses of AJ formation and cellular tracking during rounding morphogenesis showed cellular rearrangement, probably through AJ remodeling. The rearrangement occurs at the cell mass level, but not single-cell level. Hypersensitive α-catenin mutant-expressing cells did not show cellular rearrangement at the cell mass level, suggesting that the appropriate tension sensitivity of α-catenin is crucial for the coordinated round morphogenesis.

Numerous organs in the bodies of animals, including the lung, kidney, and mammary gland, contain ramified networks of epithelial tubes. These structures arise during development via a process known as branching morphogenesis. Previous studies have shown that mechanical forces directly impact this process, but the patterns of mechanical stress exerted by branching embryonic epithelia are not well understood. This is, in part, owing to a lack of experimental tools. Traditional traction force microscopy assays rely on the use of compliant hydrogels with well-defined mechanical properties. Isolated embryonic epithelial explants, however, have only been shown to branch in three-dimensional matrices of reconstituted basement membrane protein, or Matrigel, a biomaterial with poorly characterized mechanical behavior, especially in the regime of large deformations. Here, to compute the traction stresses generated by branching epithelial explants, we quantified the finite-deformation constitutive behavior of gels of reconstituted basement membrane protein subjected to multi-axial mechanical loads. We then modified the mesenchyme-free assay for the ex vivo culture of isolated embryonic airway epithelial explants by suspending fluorescent microspheres within the surrounding gel and tracking their motion during culture. Surprisingly, the tracked bead motion was non-zero in regions of the gel far away from the explants, suggestive of passive swelling deformations within the matrix. To compute accurate traction stresses, these swelling deformations must be decomposed from those generated by the branching explants. We thus tracked the motion of beads suspended within cell-free matrices and quantified spatiotemporal patterns of gel swelling. Taken together, these passive swelling data can be combined with the measured mechanical properties of the gel to compute the traction forces exerted by intact embryonic epithelial explants.

The organization of the microtubule cytoskeleton is critical for cell and organ morphogenesis. The evolutionarily conserved microtubule-severing enzyme KATANIN plays critical roles in microtubule organization in the plant and animal kingdoms. We previously used conical cell of Arabidopsis thaliana petals as a model system to investigate cortical microtubule organization and cell morphogenesis and determined that KATANIN promotes the formation of circumferential cortical microtubule arrays in conical cells. Here, we demonstrate that the conserved protein phosphatase PP2A interacts with and dephosphorylates KATANIN to promote the formation of circumferential cortical microtubule arrays in conical cells. KATANIN undergoes cycles of phosphorylation and dephosphorylation. Using co-immunoprecipitation coupled with mass spectrometry, we identified PP2A subunits as KATANIN-interacting proteins. Further biochemical studies showed that PP2A interacts with and dephosphorylates KATANIN to stabilize its cellular abundance. Similar to the katanin mutant, mutants for genes encoding PP2A subunits showed disordered cortical microtubule arrays and defective conical cell shape. Taken together, these findings identify PP2A as a regulator of conical cell shape and suggest that PP2A mediates KATANIN phospho-regulation during plant cell morphogenesis.

Low temperature in early spring impairs wheat growth and grain yield. However, little is known about the cytological and molecular mechanisms underlying low temperature regulation of wheat spike development. Microstructure observation and transcriptome sequencing of wheat spikes under low temperature were conducted. Low temperature slowed spike development, reduced the yield-component parameters of wheat spikes at the harvest stage, delayed the formation of lateral spikelets and tissue development, and induced the early differentiation of terminal spikelets. Low temperature increased the content of abscisic acid and caused the upregulation of genes in the abscisic acid signaling pathway, including those encoding PP2Cs, SnRK2s, and bZIP transcription factors. Low temperature also induced the upregulation of 33 cold-responsive genes involved in wheat response to low-temperature stress and regulation of abscisic acid biosynthesis and metabolism of other substances. The wheat spike adapted to cold conditions by changing the expression levels of genes involved in spike morphogenesis, including the transcription-factor genes MADS6, ERF4, ERF78, WOX6, and NAC48. These findings suggest that low temperature in early spring delays wheat spike development by increasing abscisic acid content or affecting the expression of genes involved in morphogenesis.

During the maturation phase of flower development, the onset of anthesis visibly marks the transition from buds to open flowers, during which petals stretch out, nectar secretion commences, and pollination occurs. Analysis of the metabolic changes occurring during this developmental transition has primarily focused on specific classes of metabolites, such as pigments and scent emission, and far less on the whole network of primary and secondary metabolites. To investigate the metabolic changes occurring at anthesis, we performed multi-platform metabolomics alongside RNA sequencing in individual florets harvested from the main inflorescence of Arabidopsis (Arabidopsis thaliana) ecotype Col-0. To trace metabolic fluxes at the level of the whole inflorescence and individual florets, we further integrated these studies with radiolabeled experiments. These extensive analyses revealed high-energy-level metabolism and transport of carbohydrates and amino acids, supporting intense metabolic rearrangements occurring at the time of this floral transition. These comprehensive data are discussed in the context of our current understanding of the metabolic shifts underlying flower opening. We envision that this analysis will facilitate the introgression of floral metabolic traits promoting pollination in crop species for which a comprehensive knowledge of flower metabolism is still limited. ispartof: PLANT PHYSIOLOGY vol:190 issue:1 pages:319-339 ispartof: location:United States status: published

Microtubule-associated proteins regulate the dynamics, organization, and function of microtubules, impacting a number of vital cellular processes. CRMPs have been shown to control microtubule assembly and axon outgrowth during neuronal differentiation. While many microtubule-associated proteins have been linked to roles in cell division and neuronal development, it is still unclear the complement that control the formation of parallel microtubule arrays in epithelial cells.Here we show through time-lapse DIC microscopy that Caenorhabditis elegans embryos homozygous for the weak loss-of-function allele unc-33(e204) progress more slowly through epidermal morphogenesis, while animals homozygous for strong loss-of-function alleles exhibit more embryonic lethality. Identification of two novel missense mutations in unc-33(e572), Val476Gly, and Ser731Thr, lead to computational approaches to determine the potential effects of these changes on UNC-33/CRMP structure. Molecular dynamics simulations show that for Asp389Asn and Arg502His, two other known missense mutations, local changes in protein-protein hydrogen bonding affect the stability of the protein. However, the Val476Gly/Ser731Thr combination does not alter the structure or energetics of UNC-33 drastically when compared to the wild-type protein.These results support a novel role for UNC-33/CRMP in C. elegans epidermal development and shed light on how individual amino acid changes cause a loss-of-function in UNC-33.

Proper ectodermal patterning during human development requires previously identified transcription factors such as GATA3 and p63, as well as positional signaling from regional mesoderm(1–6). However, the mechanism by which ectoderm and mesoderm factors act to stably pattern gene expression and lineage commitment remains poorly understood. Here we identify the previously unstudied protein Gibbin, encoded by the Xia-Gibbs AT-hook DNA Binding Motif Containing 1 (AHDC1) disease gene(7–9), as a key regulator of early epithelial morphogenesis. We find that enhancer/promoter-bound Gibbin interacts with dozens of sequence-specific zinc-finger transcription factors and methyl-CpG binding proteins to regulate expression of mesoderm genes. Gibbin loss causes an increase in DNA methylation at GATA3-dependent mesodermal genes, resulting in loss of signaling between developing dermal and epidermal cell types. Strikingly, Gibbin-mutant hESC-derived skin organoids lack dermal maturation, resulting in p63-expressing basal cells that possess defective keratinocyte stratification. Novel in vivo chimeric CRISPR mouse mutants reveal a spectrum of Gibbin-dependent developmental patterning defects affecting craniofacial structure, abdominal wall closure, and epidermal stratification that mirror patient phenotypes. Our results indicate that the patterning phenotypes seen in Xia-Gibbs and related syndromes derive from abnormal mesoderm maturation as a result of gene-specific DNA methylation decisions.

Septate junctions (SJs) perform an occluding function in invertebrate epithelia and consist of parallel septa extending across the intercellular space between neighbouring cells. In addition, they are required for several morphogenetic processes in arthropods. The biogenesis of SJs during development is inadequately studied and it was characterised in detail only for various epithelia of Drosophila melanogaster. This paper provides a detailed analysis of the ultrastructural differentiation of SJs in the epidermis of the terrestrial isopod Porcellio scaber during embryonic and postembryonic development. In this study, mid-stage embryo S13 was the earliest stage in which single septa were observed basally to the adherens junction (AJ). Differentiation of SJs during further development includes gradual elongation of septa arrays and formation of continuous arrays of septa. The enlargement of SJs in the epidermis is most pronounced at the transition from embryonic to postembryonic development and after the release of mancae from the marsupium. SJs of postmarsupial mancae are similar to those of adults, but are not yet as extensive. Comparison of the differentiation of SJs in the epidermis and hindgut of P. scaber, reveals a similar sequence of events. In addition, remodelling of SJs was observed in the epidermis of late marsupial mancae, the stage of cuticle renewal. Common features of SJs’ biogenesis in P. scaber and D. melanogaster ectodermal epithelia are indicated.

Signal transduction by the Toll-like receptors (TLRs) is conserved and essential for innate immunity in metazoans. The founding member of the TLR family

Angiogenesis is necessary for wound healing, tumorigenesis, implant inosculation, and homeostasis. In each situation, matrix structure and mechanics play a role in determining whether new vasculatures can establish transport to new or hypoxic tissues. Neovessel growth and directional guidance are sensitive to three-dimensional (3-D) matrix anisotropy and density, although the individual and integrated roles of these matrix features have not been fully recapitulated in vitro. We developed a tension-based method to align 3-D collagen constructs seeded with microvessel fragments in matrices of three levels of collagen fibril anisotropy and two levels of collagen density. The extent and direction of neovessel growth from the parent microvessel fragments increased with matrix anisotropy and decreased with density. The proangiogenic effects of anisotropy were attenuated at higher matrix densities. We also examined the impact of matrix anisotropy in an experimental model of neovessel invasion across a tissue interface. Matrix density was found to dictate the success of interface crossing, whereas interface curvature and fibril alignment were found to control directional guidance. Our findings indicate that complex configurations of matrix density and alignment can facilitate or complicate the establishment or maintenance of vascular networks in pathological and homeostatic angiogenesis. Furthermore, we extend preexisting methods for tuning collagen anisotropy in thick constructs. This approach addresses gaps in tissue engineering and cell culture by supporting the inclusion of large multicellular structures in prealigned constructs. NEW & NOTEWORTHY Matrix anisotropy and density have a considerable effect on angiogenic vessel growth and directional guidance. However, the current literature relies on 2-D and simplified models of angiogenesis (e.g., tubulogenesis and vasculogenesis). We present a method to align 3-D collagen scaffolds embedded with microvessel fragments to different levels of anisotropy. Neovessel growth increases with anisotropy and decreases with density, which may guide angiogenic neovessels across tissue interfaces such as during implant inosculation and tumorigenesis.

This study presents the results of the development of numerical models for predicting the timing of apricot flowering, including using experimental data on the emergence of plants from a state of deep dormancy. The best results of approximation of the process of accumulation of the necessary cooling in the autumn–winter period were obtained using the sigmoidal function. Models that take into account the combined effect of temperature and photoperiod on the processes of spring development showed a high accuracy of the process of accumulation of thermal units. Based on the results of testing, two models were selected with an accuracy of 3.0 days for the start of flowering and the absence of a systematic bias, which can be considered a good quality assessment These models describe well the interannual variability of apricot flowering dates and can be used to predict these dates. The discrepancy is no more than 2–4 days in 87–89% of cases. Estimates of the timing of flowering and the end of deep dormancy are very important for increasing the profitability of fruit production in the South of Russia without incurring additional costs, by minimizing the risks associated with irrational crop placement and the selection of varieties without taking into account the specifics of climate change. When constructing a system of protective measures and dates of treatments, it is also necessary to take into account the calendar dates of the shift in the development of plants.