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Results for “developmental biology”

Search indexed bioRxiv preprints in genomics, neuroscience, cell biology and bioinformatics. Read source abstracts and check manuscript versions; preprints are not peer reviewed.

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At least 19 recordsLinked to original sources

Developing Future Biologists: creating and assessing a portable short course to engage underrepresented undergraduate students in developmental biology

Many barriers discourage underrepresented students from pursuing science careers. To access graduate education, undergraduate students must first gain exposure to a particular subject and subsequently accumulate related coursework and research experience. Many underrepresented students lack exposure to developmental biology due to limited undergraduate course offerings and finite resources at smaller institutions. To address this disparity, a group of University of Michigan graduate students and postdoctoral fellows created a portable short course focusing on developmental biology, titled \"Developing Future Biologists\" (DFB). This weeklong educational initiative provides hands-on laboratory sessions, interactive lectures, and professional development workshops to teach students about developmental biology and increase awareness of scientific career options. To evaluate course effectiveness, we developed a pre-post assessment, incorporating main ideas from the BioCore Guide. Student understanding of basic concepts and perceived experience in developmental biology increased in DFB participants, despite the abbreviated nature of the course. Here, we provide all course materials and an in-depth analysis of the assessment we created. The DFB portable short course model is an easily adaptable tool that connects undergraduate students with opportunities for advanced study and lowers barriers for underrepresented students in science, technology, engineering, and mathematics.

scientific communication and education↗

Bayesian phylodynamics for developmental biology: incorporating age-dependence

As novel technologies for single-cell lineage tracing emerge, phylogenetic and phylodynamic tools are increasingly being used to study developmental processes. However, traditional phylodynamic methods, which were originally developed to study viral evolution, rely on assumptions that are difficult to justify in developmental contexts. Notably, due to cells dividing after characteristic generation times rather than after exponential waiting times--as assumed by the traditionally used birth-death model--empirical cell lineage trees deviate from birth-death phylogenies. Here, we present a non-trivial extension of the birth-death phylodynamic model that captures this characteristic feature of development. By applying our method to a public dataset of stem cell colonies, we show how previous estimates of the underlying population-dynamic parameters were biased by the choice of a birth-death tree prior. Beyond developmental biology, our framework provides an approach for analyzing systems where classical birth-death assumptions may be violated or where empirical tree shapes are poorly captured by those expected under standard phylodynamic models. Our method is available as a BEAST2 package. SignificanceApplying phylodynamic inference methods to data from developmental biology requires reassessment of the foundational assumptions underlying these tools. We show that cell population dynamics can be captured by an age-dependent branching process, as opposed to the widely used birth-death process. We develop computational methodology for efficient phylodynamic inference under this age-dependent model, thus providing a tool for connecting cell population dynamics to lineage trees. Our method is furthermore, to our knowledge, the first performant implementation of an age-dependent phylodynamic likelihood, and may be more generally applicable to systems which are ill-characterized by traditional birth-death models.

developmental biology↗

An Improved Fertilization Protocol for Ascidiella aspersa: Promoting a New Chordate Model in Developmental Biology

The invasive ascidian Ascidiella aspersa is known to be globally distributed (Muller, 1776) and characterized by its ultra-transparent embryos (Shito et al., 2021), which are ideal for studies of developmental biology and bioimaging. However, its use as a model organism has been limited due to the exceptionally low fertilization rate of dechorionated eggs. In this study, we present a new fertilization protocol that drastically increases the fertilization rate from below 10% to 80%, allowing for synchronously developing embryos without polyspermy. This protocol promotes the adoption of ascidian Ascidiella aspersa as a new chordate model in developmental biology. Summary statementEstablishment of fertilization protocols for the transparent ascidian Ascidiella aspersa as a new model for chordate development studies.

developmental biology↗

Coalescent models for developmental biology and the spatio-temporal dynamics of growing tissues.

Development is a process that needs to tightly coordinated in both space and time. Cell tracking and lineage tracing have become important experimental techniques in developmental biology and allow us to map the fate of cells and their progeny in both space and time. A generic feature of developing (as well as homeostatic) tissues that these analyses have revealed is that relatively few cells give rise to the bulk of the cells in a tissue; the lineages of most cells come to an end fairly quickly. This has spurned the interest also of computational and theoretical biologists/physicists who have developed a range of modelling - perhaps most notably are the agent-based modelling (ABM) -- approaches. These can become computationally prohibitively expensive but seem to capture some of the features observed in experiments. Here we develop a complementary perspective that allows us to understand the dynamics leading to the formation of a tissue (or colony of cells). Borrowing from the rich population genetics literature we develop genealogical models of tissue development that trace the ancestry of cells in a tissue back to their most recent common ancestors. We apply this approach to tissues that grow under confined conditions -- as would, for example, be appropriate for the neural crest -- and unbounded growth -- illustrative of the behaviour of 2D tumours or bacterial colonies. The classical coalescent model from population genetics is readily adapted to capture tissue genealogies for different models of tissue growth and development. We show that simple but universal scaling relationships allow us to establish relationships between the coalescent and different fractal growth models that have been extensively studied in many different contexts, including developmental biology. Using our genealogical perspective we are able to study the statistical properties of the processes that give rise to tissues of cells, without the need for large-scale simulations.

Developmental Biology↗

A phylogenomic framework and timescale for comparative genomics and evolutionary developmental biology of tunicates

BackgroundTunicates are the closest relatives of vertebrates and are widely used as models to study the evolutionary developmental biology of chordates. Their phylogeny, however, remains poorly understood and to date, only the 18S rRNA nuclear gene and mitogenomes have been used to delineate the major groups of tunicates. To resolve their evolutionary relationships and provide a first estimate of their divergence times, we used a transcriptomic approach to build a phylogenomic dataset including all major tunicate lineages, consisting of 258 evolutionarily conserved orthologous genes from representative species.\n\nResultsPhylogenetic analyses using site-heterogeneous CAT mixture models of amino acid sequence evolution resulted in a strongly supported tree topology resolving the relationships among four major tunicate clades: 1) Appendicularia, 2) Thaliacea + Phlebobranchia + Aplousobranchia, 3) Molgulidae, and 4) Styelidae + Pyuridae. Notably, the morphologically derived Thaliacea are confirmed as the sister-group of the clade uniting Phlebobranchia + Aplousobranchia within which the precise position of the model ascidian genus Ciona remains uncertain. Relaxed molecular clock analyses accommodating the accelerated evolutionary rate of tunicates reveal ancient diversification (~450-350 million years ago) among the major groups and allow comparing their evolutionary age with respect to the major vertebrate model lineages.\n\nConclusionsOur study represents the most comprehensive phylogenomic dataset for the main tunicate lineages. It offers a reference phylogenetic framework and first tentative timescale for tunicates, allowing the direct comparison with vertebrate model species in comparative genomics and evolutionary developmental biology studies.

evolutionary biology↗

3D-printable tools for developmental biology: Improving embryo injection and screening techniques through 3D-printing technology

Developmental biology requires rapid embryo injections and screening. We applied new affordable high-resolution 3D-printing to create five easily modifiable stamp-mold tools that greatly increase injection and screening speed, while simultaneously reducing the harmful aspects of these processes. We designed two stamps that use different approaches to improve the injection efficiency for two different types of embryo, first for embryos from the snail Crepidula fornicata, and second, for those from the spider Parasteatoda tepidariorum. Both drastically improved injection speeds and embryo survival rates, even in novice hands. The other three tools were designed for rapid side-by-side organism orientating and comparison. The first screening tool allows for optimal imaging in Xenopus laevis tadpoles, while the second and third facilitate rapid high-throughput screening of Xenopus tropicalis tadpoles and Danio rerio juveniles, respectively. These designs can act as templates for many injection or screening applications.

developmental biology↗

The tuxedo sea urchin Mespilia globulus: A fast-developing and tractable model for genomic and developmental biology

Sea urchins are pivotal models in cellular and developmental biology, but their biphasic life cycle with an extended larval life limits the ability to study post-metamorphosis and adult characters. Here, we introduce a genomically-enabled model system, the tuxedo urchin Mespilia globulus, which has rapid access to late life stages in sea urchins. We describe how we cultured M. globulus in a landlocked marine facility, raised larvae under artificial conditions and closed their life cycle. We established the experimental tractability of M. globulus: we labelled transcripts by hybridization chain reaction (HCR), and knocked out pigmentation genes to produce albino larvae using CRISPR/Cas9. We generated chromosome-scale genome assemblies for two individuals representing both sexes and two color morphs (red and blue), and compared the organisation of the 21 chromosomes of M. globulus with that of other camarodont echinoid models. We determined that M. globulus showed a conservative gene repertoire lacking the gene family expansions seen in other camarodont sea urchins. We annotated the complement of genes associated with pigmentation, immune and nervous systems and profiled their expressions in tissues and organs. Finally, we surveyed sex-related regions in genomes using genome assemblies and resequencing data, finding no evidence of heteromorphic sex chromosomes in M. globulus. Our findings highlight the accessibility of this new sea urchin model for studying the metamorphosis and adult biology of sea urchins.

evolutionary biology↗

Establishment of an in vitro culture system to study the developmental biology (growth, mating and nodule formation) of Onchocerca volvulus with implications for anti-onchocerca drug discovery and screening

Background Infections with Onchocerca volvulus nematodes remain a threat in Sub-Saharan Africa after two decades of ivermectin mass drug administration. Despite this effort, there is still an urgent need for understanding the parasite biology, especially mating behaviour and nodule formation, as well as development of more potent drugs that can clear the developmental (L3, L4, L5) and adult stages of the parasite and inhibit parasite’s reproductive and behavioural pattern.Methodology/Principal Findings Prior to culture, freshly harvested O. volvulus L3 larvae from dissected Simulium were purified by centrifugation using a 30% Percoll solution to eliminate fly tissue debris and contaminants. Parasites were cultured in both cell-free and cell-based co-culture systems, and monitored daily by microscopic visual inspection. Exhausted culture medium was replenished every 2–3 days. The cell-free culture system supported the viability and motility of O. volvulus larvae for up to 84 days (DMEM–10%NCS), while the co-culture system (DMEM–10%FBS–LLC-MK2) extended the worm survival period to 315 days. Co-culture systems alone promoted the two consecutive parasite moults (L3 to L4 and L4 to L5) with highest moulting rates observed in DMEM–10%FBS–LLC-MK2 (69.2±30 %), while no moult was observed in DMEM–10%NCS–LEC condition. O. volvulus adult worms mating and even mating competitions were observed in DMEM–10% FBS –LLC-MK2 co-culture system. Early nodulogenesis was observed in both DMEM–10% FBS–LLC-MK2 and DMEM– 10%NCS–LLC-MK2 systems.Conclusions/Significance The present study describes an in vitro system in which O. volvulus L3 larvae can be maintained in culture leading to the development of reproductive adult stages. Thus, this platform gives potential for the investigation of mating, mating competition and early stage of nodulogenesis of O. volvulus adult worms that can be used as additional targets for onchocercacidal drug screening.Author summary River blindness affects people living in mostly remote and underserved rural communities in some of the poorest areas of the world. Although significant efforts have been achieved towards the reduction of disease morbidity, onchocerciasis still affect million of people in Sub-Saharan Africa. The current control strategy is the annual mass administration of ivermectin which have accumulated several drawbacks overtime: as the sole microfilaricidal action of the drug, very long treatment period (15-17 years) and reports of ivermectin losing its efficacy; Therefore, raising the urgent need for new onchocercacidal molecules. Our study has established an in vitro platform capable of supporting the growth and development of all developmental stages of O. volvulus (L3 infective stage, L4, L5 and adult worms), moreover the platform provided more insight on O. volvulus adult worms reproductive and behavioural pattern. Our findings provide more avenues for mass production of different parasite stages, the investigation of parasite developmental biology and the identification of targets for drug discovery against different phases of development of this filaria parasiteAbbreviationsAPOCAfrican Programme for Onchocerciasis ControlOCPOnchocerciasis Control ProgrammePTSPost-Treatment SurveillanceHC-04Human Hepatocyte cellsHEK-293embryonic human kidneys cellsLLC-MK2Monkey Kidney cellsLECMouse embryonic lung cellsL3Infective LarvaeL4Stage 4 larvaeL5Stage 5 larvaeRPMIRoswell Park Memorial InstituteDMEMDulbecco’s Minimum Essential MediumMEMMinimum Essential MediumIMDMIscove’s Modified Dulbecco MediumNCTCNew jersey Cell Type CollectionNCSNew-born Calf SerumFBSFoetal Bovine SerumBCSBovine Calf SerumMDAMass Drug AdministrationWHOWorld Health OrganisationCMFLCommunity Microfilariae LoadsEGFEpidermal Growth FactorTGF-αTransforming Growth Factor - alphaIGF - IInsulin-like Growth Factor – IPDGFPalettes-Derived Growth FactorDDTDichlorodiphenyltrichloroethane.View Full Text

developmental biology↗

Modeling human phenotypes in the nematode C. elegans during an undergraduate developmental biology course

Caenorhabditis elegans is a widely used model organism in biomedical research due to its genetic tractability, short life cycle, and conservation of many developmental processes with humans. In this study, undergraduate students conducted nine independent experiments during a Developmental Biology course to model human phenotypes using C. elegans. Each group selected a human phenotype of interest, identified a gene associated with the phenotype, and then determined the orthologous or homologous gene in C. elegans. By obtaining mutants and designing phenotypic assays, students investigated the extent to which the worm models could recapitulate aspects of the human condition. This collective work highlights both the potential and limitations of C. elegans as a model for human phenotypic variation and disease and demonstrates the value of undergraduate inquiry as a catalyst for scientific engagement and research-based learning.

scientific communication and education↗

The buds of Oscarella lobularis (Porifera): a new convenient model for sponge cell and developmental biology

The comparative study of the four non-bilaterian phyla (Cnidaria, Placozoa, Ctenophora, Porifera) should provide insights into the origin of bilaterian traits. Except for Cnidaria, present knowledge on the cell biology and development of these animals is so far limited. Non-bilaterian models are needed to get further into cell architecture and molecular mechanisms. Given the developmental, histological, ecological and genomic differences between the four sponge classes, we develop a new sponge model: the buds of the Oscarella lobularis (class Homoscleromorpha). This experimental model supplements the two other most famous sponge models Amphimedon queenslandica and Ephydatia muelleri, both belonging to the class Demospongiae. Budding is a natural and spontaneous asexual reproduction mean, but budding can be triggered in vitro ensuring availability of biological material all year long. We provide a full description of buds, from their formation to their development into juveniles. Their transparency enables fluorescent and live imaging, and their abundance allows for experimental replicates. Moreover, regeneration and cell reaggregation capabilities provide interesting experimental morphogenetic contexts. The numerous techniques now mastered on these buds make it a new suitable sponge model. Summary statementStudying sponge biology is needed to understand the evolution of metazoans. We developed a new model suitable for experimental biology that allows to study morphogenetic processes with modern tools.

zoology↗

Distinctive spore architecture and developmental biology of Turicibacter sanguinis reveal unexpected diversity among gut spore formers

Sporulation is a widespread but incompletely characterized trait among gut commensals, where it underpins microbial persistence, transmission, and ecological resilience. Most insights into spore biology derive from Bacilli and Clostridia, yet little is known about sporulation in phylogenetically distant gut-associated lineages. Turicibacter sanguinis, a strict anaerobe linked to host serotonin metabolism, lipid homeostasis, and neurodegenerative disease, represents one such understudied taxon. Here, we integrate ultrastructural, physiological, and comparative genomic analyses to define the sporulation and germination program of T. sanguinis. We show that T. sanguinis forms heat-resistant spores with a canonical core-cortex-coat architecture but displays previously undescribed features including a dual-layered outer envelope and bimodal electron-dense coat morphotypes. Developmental stages of sporulation follow canonical stages of Bacillus- and Clostridium-like sporulation while genomic analyses reveal a hybrid regulatory architecture combining Clostridial-type Spo0A initiation with Bacillus-like late-stage sigma factor control. Germination assays and genomic signatures further indicate a nutrient-responsive, Bacillus-like pathway involving Ger-family receptors, SpoVA-mediated Ca-DPA release, and CwlJ- and SleM-type cortex hydrolases. Together, these findings identify T. sanguinis as a distinct spore-forming lineage within the human gut microbiota and expand the known diversity of sporulation strategies across the Firmicutes.

microbiology↗

The pomegranate (Punica granatum L.) genome provides insights into fruit quality and ovule developmental biology

Pomegranate (Punica granatum L.) with an uncertain taxonomic status has an ancient cultivation history, and has become an emerging fruit due to its attractive features such as the bright red appearance and the high abundance of medicinally valuable ellagitannin-based compounds in its peel and aril. However, the absence of genomic resources has restricted further elucidating genetics and evolution of these interesting traits. Here we report a 274-Mb high-quality draft pomegranate genome sequence, which covers approximately 81.5% of the estimated 336 Mb genome, consists of 2,177 scaffolds with an N50 size of 1.7 Mb, and contains 30,903 genes. Phylogenomic analysis supported that pomegranate belongs to the Lythraceae family rather than the monogeneric Punicaceae family, and comparative analyses showed that pomegranate and Eucalyptus grandis shares the paleotetraploidy event. Integrated genomic and transcriptomic analyses provided insights into the molecular mechanisms underlying the biosynthesis of ellagitannin-based compounds, the color formation in both peels and arils during pomegranate fruit development, and the unique ovule development processes that are characteristic of pomegranate. This genome sequence represents the first reference in Lythraceae, providing an important resource to expand our understanding of some unique biological processes and to facilitate both comparative biology studies and crop breeding.

genomics↗

Optical tissue clearing and 3D imaging of intact primate testicular tissue: a novel technology development

Classical histology struggles to preserve three-dimensional spatial context, prompting the emergence of optical tissue clearing techniques that enable imaging of intact specimens at cellular or subcellular resolution. These techniques have revolutionised fields like cell biology, developmental biology, and neuroscience. However, their application in reproductive biology remains unexplored - particularly in studying the complexities of testicular development. We developed a novel, efficient and affordable toolbox for studying intact testicular tissues, PT-CLEAR3D, that stands for primate testis - whole mount staining, tissue clearing and three-dimensional imaging. Intact testicular tissues from humans (transgender model), common marmosets and macaques underwent antibody labelling, clearing with organic solvents, and three-dimensional imaging using light sheet fluorescence microscopy. Marker specificity was confirmed by immunofluorescence staining of 3 and 25 {micro}m testicular sections, followed by imaging with confocal. The testicular structure was evaluated using several markers: spermatogonia (melanoma-associated antigen 4), least differentiated spermatogonia (Piwi-like protein 4), Sertoli cells (vimentin and SRY-Box transcription Factor 9), peritubular myoid cells and vasculature (alpha-smooth muscle actin), and NucSpot as a nuclear dye. PT-CLEAR3D efficiently achieved optical transparency while a commercial kit that was ran in parallel was inefficient. This study presents a pioneering three-dimensional visualization of intact testicular samples of up to 50 mm3 in size and imaging depth of up to 4.5 mm across three primate species. Remarkably, PT-CLEAR3D revealed critical details at both tissue and cellular levels such as the spatial distribution of germ and somatic cells, cellular bridges, and vasculature. Furthermore, PT-CLEAR3D enabled three-dimensional reconstructions that effectively reduce confirmation bias enhancing our observation of spermatogonial clones organized as single cells, pairs, and quartets. Importantly, it adeptly identified testicular pathology and the persistence of germ cell clones in select tubules within the transgender testis following hormonal suppression of spermatogenesis. This technological development offers a versatile toolbox with benefits such as applicability across multiple species, fluorophore multiplexing, compatibility with different fixatives and deep tissue volumetric imaging with cellular resolution. Overall, PT-CLEAR3D establishes a foundation for spatial evaluation of testicular development, presenting substantial potential for advancing our understanding of the intricate kinetics of spermatogenesis in health and disease.

developmental biology↗

CYK-4 functions independently of its centralspindlin partner ZEN-4 to cellularize oocytes in germline syncytia

Throughout metazoans, germ cells undergo incomplete cytokinesis to form syncytia connected by intercellular bridges. Formation of gametes ultimately requires bridge closure. Here, we investigate the contribution of the conserved bridge component centralspindlin to oocyte production in C. elegans. Centralspindlin is composed of the Rho family GTPase-activating protein (GAP) CYK-4/MgcRacGAP and the microtubule motor ZEN-4/kinesin-6, which are both essential for cytokinesis. In contrast, we show that oocyte production by the syncytial germline requires CYK-4 but not ZEN-4. Longitudinal imaging after conditional CYK-4 inactivation revealed a role in oocyte cellularization, rather than in generation of syncytial compartments. CYK-4s lipid-binding C1 domain and the GTPase-binding interface of its GAP domain were individually important for oocyte cellularization and for targeting CYK-4 to bridges, where it contributes to enrichment of active RhoA. These results identify a C1-GAP module in CYK-4 that recruits it to bridges in the germline and directs their closure to produce oocytes.\n\nIMPACT STATEMENTThe CYK-4 subunit of centralspindlin, a broadly conserved component of intercellular bridges across metazoa, is required for the cytokinesis-like closure of intercellular bridges that cellularizes oocytes to separate them from germline syncytia.\n\nMAJOR SUBJECT AREASCell Biology, Developmental Biology & Stem Cells

cell biology↗

High school Internship Program in Integrated Mathematical Oncology (HIP IMO) - five-year experience at Moffitt Cancer Center

Modern cancer research, and the wealth of data across multiple spatial and temporal scales, has created the need for researchers that are well-versed in the life sciences (cancer biology, developmental biology, immunology), medical sciences (oncology) and natural sciences (mathematics, physics, engineering, computer sciences). College undergraduate education is traditionally provided in disciplinary silos, which creates a steep learning curve at the graduate and postdoctoral levels that increasingly bridge multiple disciplines. Numerous colleges have begun to embrace interdisciplinary curricula, but students who double-major in mathematics (or other quantitative sciences) and biology (or medicine) remain scarce. We identified the need to educate junior and senior high school students about integrating mathematical and biological skills, through the lens of mathematical oncology, to better prepare students for future careers at the interdisciplinary interface. The High school Internship Program in Integrated Mathematical Oncology (HIP IMO) at Moffitt Cancer Center has so far trained 59 students between 2015 and 2019. We report here on the program structure, training deliverables, curriculum, and outcomes. We hope to promote such interdisciplinary educational activities early in a students career.

scientific communication and education↗

Molecular mechanisms governing circulating immune cell heterogeneity across different species revealed by single cell sequencing

BackgroundImmune cells play important roles in mediating immune response and host defense against invading pathogens. However, insights into the molecular mechanisms governing circulating immune cell diversity among multiple species are limited. MethodsIn this study, we compared the single-cell transcriptomes of 77{square}957 immune cells from 12 species using single-cell RNA-sequencing (scRNA-seq). Distinct molecular profiles were characterized for different immune cell types, including T cells, B cells, natural killer cells, monocytes, and dendritic cells. ResultsResults revealed the heterogeneity and compositions of circulating immune cells among 12 different species. Additionally, we explored the conserved and divergent cellular crosstalk and genetic regulatory networks among vertebrate immune cells. Notably, the ligand and receptor pair VIM-CD44 was highly conserved among the immune cells. ConclusionsThis study is the first to provide a comprehensive analysis of the cross-species single-cell atlas for peripheral blood mononuclear cells (PBMCs). This research should advance our understanding of the cellular taxonomy and fundamental functions of PBMCs, with important implications in evolutionary biology, developmental biology, and immune system disorders.

cell biology↗

Observing concurrent subcellular dynamics in large living tissues

An outstanding question in eukaryotic biology is the mechanistic connection between events occurring at (sub)cellular levels (time scales of milliseconds to minutes) to those at the tissue levels (tens of minutes to months). Deciphering such mechanisms requires imaging approaches capable of simultaneously achieving high spatial and temporal resolutions for large samples over long periods of time. Here, we demonstrate Airy beam-based light sheet microscopy of organelles in tens to hundreds of cells in a few hundred micrometre-wide tissue environments. We achieve a typical resolution of 320 nm over 266 x 266 x 100 m3 volumes at a temporal rate of 0.05 Hz, typically with generally used fluorophores such as Green Fluorescent Protein, over extended periods of time that allow tracking of organelle and protein dynamics. We validated our approach across different length and time scales by imaging mitochondria and endosome dynamics in very large fields of view in zebrafish tissue, molecular assemblies of myosin as gastrulation proceeds in Drosophila embryos, 3D mitochondrial streaming in mouse oocytes, pressure-driven motility and protrusions in amoebae, mitochondrial dynamics in cancer spheroids, 5 -colour fast imaging in iBlastoids, and endosomal dynamics in single cells. Through these model systems, we demonstrate the versatility of Airy beam light sheet microscopy to image large tissues at unprecedented high resolution; to capture dynamics in photosensitive, delicate samples; and to screen 3D samples. We anticipate that our Airy beam-based approach will represent a pivotal advance in cellular biology--especially developmental biology--as it provides, for the first time, true subcellular resolution over large imaging volumes with high temporal resolution.

developmental biology↗

Metabolic enhancement of mammalian developmental pausing

The quest to model and modulate embryonic development became a recent cornerstone of stem cell and developmental biology. Mammalian developmental timing is adjustable in vivo by preserving preimplantation embryos in a dormant state called diapause. Inhibition of the growth regulator mTOR (mTORi) pauses mouse development in vitro, yet constraints to pause duration are unrecognized. By comparing the response of embryonic and extraembryonic stem cells to mTORi-induced pausing, we identified lipid usage as a bottleneck to developmental pausing. Enhancing fatty acid oxidation (FAO) boosts embryo longevity, while blocking it reduces the pausing capacity. Genomic and metabolic analyses of single embryos point toward a deeper dormant state in FAO-enhanced pausing and reveal a link between lipid metabolism and embryo morphology. Our results lift a constraint on in vitro embryo survival and suggest that lipid metabolism may be a critical metabolic transition relevant for longevity and stem cell function across tissues. One-Sentence SummaryFacilitating fatty acid oxidation by carnitine supplementation enhances mTOR inhibition-mediated developmental pausing.

developmental biology↗