Biology subjects

Borchiellini, C.

Publications and source records attributed to Borchiellini, C..

6 recordsLinked to original sources

bioRxiv2024

The Oscarella sponges genus: a hidden yet colorful diversity

The identification and classification of new taxa are crucial for understanding biodiversity. However, assigning samples to new taxa requires cautious and rigorous approaches. Historically, taxonomy has heavily relied on morphological traits, which can be subjective and may not always reflect underlying genetic divergence, particularly in organisms with few diagnostic morphological traits. A prime example is the sponge genus Oscarella (Homoscleromorpha), where species delimitation is challenged by the absence of spicules and limited morphological characters. Here, we address this gap by combining an extensive genetic dataset (192 specimens, five markers) with systematic photographic documentation. This approach enabled a robust assessment of Oscarella diversity in the Western Mediterranean, resulting in the identification of four species new to science. Multigene phylogenetic analyses also enabled us to propose an evolutionary scenario for color polymorphism. Moreover, our data highlighted critical limitations in current methodologies for studying Oscarella, including the low resolution of the widely used cytochrome c oxidase subunit I (cox1/COI) gene, the lack of genetic data for many species, and insufficient information on their geographical distribution. These issues, which mirror challenges across many taxa, highlight the urgent need for standardized genetic frameworks and comprehensive datasets to improve taxonomic resolution for each taxon.

evolutionary biology↗

bioRxiv2023

Hyperaccumulation of Vanadium in animals: two sponges compete with urochordates

Vanadium (V) is the second most abundant transition metal in the oceans. Nevertheless, its concentration in organisms is generally low despite its involvement in various physiological or enzymatic functions. Because exposure to high concentrations was shown to be harmful for various organisms including animals, the unexpected very high concentrations found in urochordates and annelids yielded additional studies to decipher their biological meaning. Here we report cases of V hyperaccumulators in a distinct animal phylum (Porifera): the two homoscleromorph sponge species Oscarella lobularis and Oscarella tuberculata (up to 30 mg/g dw). These high concentrations overpass those reported previously in urochordates and annelids and are not found in the 5 other sponge species studied here. In both Oscarella species, vanadium is mainly accumulated in the 100 m surface tissues, and in particular in mesohylar cells, as vanadyl (+4) before being partly reduced to V (+3) in the deeper tissues. Genomic surveys failed to find any previously described gene implicated in vanadium metabolism, suggesting that V hyperaccumulation emerged convergently in this lineage. This feature may be of interest for developing bioremediation strategies in marine ecosystems or bioinspired processes to recycle this critical metal. SynopsisThis study reports extremely high concentrations of vanadium in two sponges. This unusual bioaccumulation of reduced V (+3) in mesohylar cells relies on unknown molecular mechanisms.

ecology↗

bioRxiv2022

The compact genome of the sponge Oopsacas minuta (Hexactinellida) is lacking key metazoan core genes

BackgroundBilaterian animals today represent 99% of animal biodiversity. Elucidating how bilaterian hallmarks emerged is a central question of animal evo-devo and evolutionary genomics. Studies of non-bilaterian genomes have suggested that the ancestral animal already possessed a diversified developmental toolkit, including some pathways required for bilaterian body plans. Comparing genomes within the early branching metazoan Porifera phylum is key to identify which changes and innovations contributed to the successful transition towards bilaterians. ResultsHere, we report the first whole genome comprehensive analysis of a glass sponge, Oopsacas minuta, a member of the Hexactinellida. Studying this class of sponge is evolutionary relevant because it differs from the three other Porifera classes in terms of development, tissue organization, ecology and physiology. Although O. minuta does not exhibit drastic body simplifications, its genome is among the smallest animal genomes sequenced so far, surprisingly lacking several metazoan core genes (including Wnt and several key transcription factors). Our study also provided the complete genome of the symbiotic organism dominating the associated microbial community: a new Thaumarchaeota species. ConclusionsThe genome of the glass sponge O. minuta differs from all other available sponge genomes by its compactness and smaller number of predicted proteins. The unexpected losses of numerous genes considered as ancestral and pivotal for metazoan morphogenetic processes most likely reflect the peculiar syncytial organization in this group. Our work further documents the importance of convergence during animal evolution, with multiple emergences of sponge skeleton, electrical signaling and multiciliated cells.

evolutionary biology↗

bioRxiv2021

Evolution of mechanisms controlling epithelial morphogenesis across animals: new insights from dissociation - reaggregation experiments in the sponge Oscarella lobularis.

BackgroundThe ancestral presence of epithelia in Metazoa is no longer debated. Even though Porifera seem to be the best candidates to be the sister group to all other Metazoa, hardly anything is known about the proteins involved in the composition of cell-cell junctions or about the mechanisms that regulate epithelial morphogenetic processes in this phylum. ResultsTo get insights into the early evolution of epithelial morphogenesis, we focused on morphogenic characteristics of the homoscleromorph sponge Oscarella lobularis. Homoscleromorpha are a sponge class with a typical basement membrane and adherens-like junctions unknown in other sponge classes. We took advantage of the dynamic context provided by cell dissociation-reaggregation experiments to explore morphogenetic processes in epithelial cells in an early lineage by combining fluorescent and electronic microscopy observations and RNA sequencing approaches at key time-points of the dissociation and reaggregation processes. ConclusionsOur results show that part of the molecular toolkit involved in the loss and restoration of epithelial features such as cell-cell and cell-matrix adhesion is conserved between Homoscleromorpha and Bilateria, suggesting their common role in the last common ancestor of animals. In addition, Sponge-specific genes are differently expressed during the dissociation and reaggregation processes, calling for future functional characterization of these genes.

evolutionary biology↗

bioRxiv2020

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↗

bioRxiv2017

NEW GENOMIC DATA AND ANALYSES CHALLENGE THE TRADITIONAL VISION OF ANIMAL EPITHELIUM EVOLUTION

The emergence of epithelia was the foundation of metazoan expansion. To investigate the early evolution of animal epithelia, we sequenced the genome and transcriptomes of two new sponge species to characterize epithelial markers such as the E-cadherin complex and the polarity complexes for all classes (Calcarea, Demospongiae, Hexactinellida, Homoscleromorpha) of sponges (phylum Porifera) and compare them with their homologs in Placozoa and in Ctenophora. We found that Placozoa and most sponges possess orthologs of all essential genes encoding proteins characteristic of bilaterian epithelial cells, as well as their conserved interaction domains. In stark contrast, we found that ctenophores lack several major polarity complex components such as the Crumbs complex and Scribble. Furthermore, the E-cadherin ctenophore ortholog exhibits a divergent cytoplasmic domain making it unlikely to interact with its canonical cytoplasmic partners. These unexpected findings challenge the current evolutionary paradigm on the emergence of epithelia.\n\nSIGNIFICANT STATEMENTEpithelial tissues are a hallmark of metazoans deeply linked to the evolution of the complex morphogenesis processes characterizing their development. However, studies on the epithelial features of non-bilaterians are still sparse and it remains unclear whether the last common metazoan ancestor possessed a fully functional epithelial toolkit or if it was acquired later during metazoan evolution. In this work, we demonstrate that if sponges have a well conserved and functionally predicted epithelial toolkit, Ctenophores have either divergent adhesion complexes or lack essential polarity complexes. Altogether, our results raise a doubt on the homology of protein complexes and structures involved in cell polarity and adhesive type junctions between Ctenophora and Bilateria epithelia.

evolutionary biology↗