Genetic and functional diversity of allorecognition receptors in the urochordate, .

Allorecognition in is controlled by a highly polymorphic locus (the ), and functionally similar to missing-self recognition utilized by Natural Killer cells-compatibility is determined by sharing a self-allele, and integration of activating and inhibitory signals determines outcome. We had found these signals were generated by two -encoded receptors, called and Here we show that genes are members of an extended family consisting of >37 loci, and co-expressed with an even more diverse gene family-the (). The are membrane proteins related to , but include conserved tyrosine motifs, including ITIMs and hemITAMs.

Comparing dormancy in two distantly related tunicates reveals morphological, molecular, and ecological convergences and repeated co-option.

Many asexually-propagating marine invertebrates can survive extreme environmental conditions by developing dormant structures, i.e., morphologically simplified bodies that retain the capacity to completely regenerate a functional adult when conditions return to normal.

Parkinson's disease related mortality: Long-term trends and impact of COVID-19 pandemic waves.

Introduction: Parkinson's disease (PD) mortality burden is increasing worldwide, but accurate estimates on the magnitude of the impact of the COVID-19 pandemic are missing. Mortality rates vary largely when considering PD as underlying cause of death (UCOD), or as one among multiple causes reported in death certificates (MCOD). The aim of this study is to assess COVID-19 impact on PD-related mortality trends using the UCOD and MCOD approach.

The Hazards of Regeneration: From Morgan's Legacy to Evo-Devo.

In his prominent book Regeneration (1901), T.H. Morgan's collected and synthesized theoretical and experimental findings from a diverse array of regenerating animals and plants.

The Onset of Whole-Body Regeneration in : Morphological and Molecular Characterization.

Colonial tunicates are the only chordates that regularly regenerate a fully functional whole body as part of their asexual life cycle, starting from specific epithelia and/or mesenchymal cells. In addition, in some species, whole-body regeneration (WBR) can also be triggered by extensive injuries, which deplete most of their tissues and organs and leave behind only small fragments of their body. In this manuscript, we characterized the onset of WBR in one colonial tunicate long used as a laboratory model We first analyzed the transcriptomic response to a WBR-triggering injury.

Articulating the "stem cell niche" paradigm through the lens of non-model aquatic invertebrates.

Stem cells (SCs) in vertebrates typically reside in "stem cell niches" (SCNs), morphologically restricted tissue microenvironments that are important for SC survival and proliferation. SCNs are broadly defined by properties including physical location, but in contrast to vertebrates and other "model" organisms, aquatic invertebrate SCs do not have clearly documented niche outlines or properties. Life strategies such as regeneration or asexual reproduction may have conditioned the niche architectural variability in aquatic or marine animal groups.

A pan-metazoan concept for adult stem cells: the wobbling Penrose landscape.

Adult stem cells (ASCs) in vertebrates and model invertebrates (e.g. Drosophila melanogaster) are typically long-lived, lineage-restricted, clonogenic and quiescent cells with somatic descendants and tissue/organ-restricted activities.

From the individual to the colony: Marine invertebrates as models to understand levels of biological organization.

The developmental and evolutionary principles of coloniality in marine animals remain largely unexplored. Although many common traits have evolved independently in different groups of colonial animals, questions about their significance for colonial life histories remain unanswered. In 2018 (Nov.

The Diversity of Muscles and Their Regenerative Potential across Animals.

Cells with contractile functions are present in almost all metazoans, and so are the related processes of muscle homeostasis and regeneration. Regeneration itself is a complex process unevenly spread across metazoans that ranges from full-body regeneration to partial reconstruction of damaged organs or body tissues, including muscles. The cellular and molecular mechanisms involved in regenerative processes can be homologous, co-opted, and/or evolved independently.

Slow evolution under purifying selection in the gamete recognition protein bindin of the sea urchin Diadema.

Bindin is a sperm protein that mediates attachment and membrane fusion of gametes. The mode of bindin evolution varies across sea urchin genera studied to date. In three genera it evolves under positive selection, in four under mostly purifying selection, and in one, results have been mixed.

Coloniality, clonality, and modularity in animals: The elephant in the room.

Nearly half of the animal phyla contain species that propagate asexually via agametic reproduction, often forming colonies of genetically identical modules, that is, ramets, zooids, or polyps. Clonal reproduction, colony formation, and modular organization have important consequences for many aspects of organismal biology. Theories in ecology, evolution, and development are often based on unitary and, mainly, strictly sexually reproducing organisms, and though colonial animals dominate many marine ecosystems and habitats, recognized concepts for the study of clonal species are often lacking.

The eventful history of nonembryonic development in tunicates.

Tunicates encompass a large group of marine filter-feeding animals and more than half of them are able to reproduce asexually by a particular form of nonembryonic development (NED) generally called budding. The phylogeny of tunicates suggests that asexual reproduction is an evolutionarily plastic trait, a view that is further reinforced by the fact that budding mechanisms differ from one species to another, involving nonhomologous tissues and cells. In this review, we explore more than 150 years of literature to provide an overview of NED diversity and we present a comparative picture of budding tissues across tunicates.

Putative stem cells in the hemolymph and in the intestinal submucosa of the solitary ascidian .

Background: In various ascidian species, circulating stem cells have been documented to be involved in asexual reproduction and whole-body regeneration. Studies of these cell population(s) are mainly restricted to colonial species. Here, we investigate the occurrence of circulating stem cells in the solitary a member of the Styelidae, a family with at least two independent origins of coloniality.

Novel budding mode in : a model for comparative studies on asexual development and whole body regeneration.

Background: In tunicates, the capacity to build an adult body via non-embryonic development (NED), i.e., asexual budding and whole body regeneration, has been gained or lost several times across the whole subphylum.

Colonial ascidians strongly preyed upon, yet dominate the substrate in a subtropical fouling community.

Higher diversity and dominance at lower latitudes has been suggested for colonial species. We verified this pattern in species richness of ascidians, finding that higher colonial-to-solitary species ratios occur in the tropics and subtropics. At the latitudinal region with the highest ratio, in southeastern Brazil, we confirmed that colonial species dominate space on artificial plates in two independent studies of five fouling communities.

Modular co-option of cardiopharyngeal genes during non-embryonic myogenesis.

Background: In chordates, cardiac and body muscles arise from different embryonic origins. In addition, myogenesis can be triggered in adult organisms, during asexual development or regeneration. In non-vertebrate chordates like ascidians, muscles originate from embryonic precursors regulated by a conserved set of genes that orchestrate cell behavior and dynamics during development.

Effectiveness of a community care management program for multimorbid elderly patients with heart failure in the Veneto Region.

Background: The rapidly growing population of elderly subjects with multimorbidity is at risk of receiving fragmented and uncoordinated care, and have frequent hospitalizations and emergency room (ER) visits.

Aims: The study aims to describe the impact of a care management program (CMP) developed in the Veneto region (Northeastern Italy) for patients affected by chronic heart failure (CHF) and multimorbidity.

Methods: The CMP was provided to 330 patients > 65 years suffering from CHF and multimorbidity.

De novo neurogenesis in a budding chordate: Co-option of larval anteroposterior patterning genes in a transitory neurogenic organ.

During metamorphosis of solitary ascidians, part of the larval tubular nervous system is recruited to form the adult central nervous system (CNS) through neural stem-like cells called ependymal cells. The anteroposterior (AP) gene expression patterning of the larval CNS regionalize the distribution of the ependymal cells, which contains the positional information of the neurons of the adult nervous system. In colonial ascidians, the CNS of asexually developed zooids has the same morphology of the one of the post-metamorphic zooids.

Convergent Acquisition of Nonembryonic Development in Styelid Ascidians.

Asexual propagation and whole body regeneration are forms of nonembryonic development (NED) widespread across animal phyla and central in life history and evolutionary diversification of metazoans. Whereas it is challenging to reconstruct the gains or losses of NED at large phylogenetic scale, comparative studies could benefit from being conducted at more restricted taxonomic scale, in groups for which phylogenetic relationships are well established. The ascidian family of Styelidae encompasses strictly sexually reproducing solitary forms as well as colonial species that combine sexual reproduction with different forms of NED.

Comparative localization of serotonin-like immunoreactive cells in Thaliacea informs tunicate phylogeny.

Background: Thaliaceans is one of the understudied classes of the phylum Tunicata. In particular, their phylogenetic relationships remain an issue of debate. The overall pattern of serotonin (5-HT) distribution is an excellent biochemical trait to interpret internal relationships at order level.

Identification of differentially expressed genes from multipotent epithelia at the onset of an asexual development.

Organisms that have evolved alternative modes of reproduction, complementary to the sexual mode, are found across metazoans. The chordate Botryllus schlosseri is an emerging model for asexual development studies. Botryllus can rebuild its entire body from a portion of adult epithelia in a continuous and stereotyped process called blastogenesis.

Redeployment of germ layers related TFs shows regionalized expression during two non-embryonic developments.

In all non-vertebrate metazoan phyla, species that evolved non-embryonic developmental pathways as means of propagation or regeneration can be found. In this context, new bodies arise through asexual reproduction processes (such as budding) or whole body regeneration, that lack the familiar temporal and spatial cues classically associated with embryogenesis, like maternal determinants, or gastrulation. The molecular mechanisms underlying those non-embryonic developments (i.

Wnt affects symmetry and morphogenesis during post-embryonic development in colonial chordates.

Background: Wnt signaling is one of the earliest and most highly conserved regulatory pathways for the establishment of the body axes during regeneration and early development. In regeneration, body axes determination occurs independently of tissue rearrangement and early developmental cues. Modulation of the Wnt signaling in either process has shown to result in unusual body axis phenotypes.

Comparative muscle development of scyphozoan jellyfish with simple and complex life cycles.

Background: Simple life cycles arise from complex life cycles when one or more developmental stages are lost. This raises a fundamental question - how can an intermediate stage, such as a larva, be removed, and development still produce a normal adult? To address this question, we examined the development in several species of pelagiid jellyfish. Most members of Pelagiidae have a complex life cycle with a sessile polyp that gives rise to ephyrae (juvenile medusae); but one species within Pelagiidae, Pelagia noctiluca, spends its whole life in the water column, developing from a larva directly into an ephyra.

Ontology for the asexual development and anatomy of the colonial chordate Botryllus schlosseri.

Ontologies provide an important resource to integrate information. For developmental biology and comparative anatomy studies, ontologies of a species are used to formalize and annotate data that are related to anatomical structures, their lineage and timing of development. Here, we have constructed the first ontology for anatomy and asexual development (blastogenesis) of a bilaterian, the colonial tunicate Botryllus schlosseri.