Alexander V Ereskovsky

• Research Director at French National Centre for Scientific Research

Sponges have a remarkable capacity to rapidly regenerate in response to injury. In addition, sponges rapidly renew their aquiferous system to maintain a healthy. This study describes the reparative regeneration in the cold‐water demosponge Halichondria panicea. The wide range of methods allow us to make a comprehensive analysis of mechanisms, which...

Agelas oroides (Schmidt, 1864) is a widely distributed Mediterranean sponge inhabiting shallow coralligenous formations as well as mesophotic depths. Although this species has been extensively studied for its specialized metabolites (e.g. bromo-pyrrole alkaloids), little is known about its internal organization, cellular components and associated p...

Spongin is a fundamental biopolymer that has played a crucial role in the skeletogenesis of keratosan sponges for over 800 million years. This biomaterial had so far remained chemically unidentified and believed to be an enigmatic type of halogenated collagen-keratin-based bioelastomer. Here we show collagen I and III as the main structural compone...

Sponges (phylum Porifera) are early-branching metazoans demonstrating an outstanding example of whole-body regeneration, cell reaggregation. During the process, single cells form aggregates capable of progressive development and reconstruction of intact sponges. This study provides the first comprehensive analysis of cell proliferation and cell dea...

A checklist of the sponge fauna from the White Sea, Russia was compiled from published literature. This study provides a partial update to the “Checklist of sponges (Porifera) of the White Sea” published about 30 years ago. A total of 86 sponge species distributed among two classes of Porifera, Demospongiae and Calcarea, were identified in the Whit...

Evolutionary and developmental biology are among the most dynamically developing areas of modern biology. Both have a long and turbulent history, especially in Russia (USSR). However, any science develops thanks to the breakthrough research of individual scientists and scientific teams. In this paper, we briefly analyzed the main theoretical works...

Archaeocytes are considered a key cell type in sponges (Porifera). They are believed to be multifunctional cells performing various functions, from nutrient digestion to acting as adult stem cells (ASCs). Thus, archaeocytes are mentioned in discussions on various aspects of sponge biology. As presumed ASCs of an early-diverged animal taxon, archaeo...

Fine structure of echiurid blood vessels in the proboscis is known in details, but the circulatory system of the trunk remains studied mainly at the level of general anatomy. The investigation of the trunk circulatory system in Bonellia viridis females revealed the presence of specialized podocytes in the ring vessel and anterior part of the ventra...

The comparative study of the four non‐bilaterian phyla (Cnidaria, Placozoa, Ctenophora, and Porifera) provides insights into the origin of bilaterian traits. To complete our knowledge of the cell biology and development of these animals, additional non‐bilaterian models are needed. Given the developmental, histological, ecological, and genomic diff...

The proboscis of Bonellia viridis Rolando, 1822 females is the best studied among the echiurids and the rich data are extrapolated to other species of echiurids. However, very little is known about the fine structure and general organization of the nervous system of B. viridis and echiurids as a whole. The microscopic anatomy and ultrastructure of...

The fine structure of echiurid blood vessels in the proboscis is known in detail, but the circulatory system of the trunk is still understood mainly at the level of general anatomy. The trunk circulatory system was studied in Bonellia viridis females, and specialized podocytes were found to form the walls of the ring vessel and the anterior part of...

Sponges (phylum Porifera) were among the first metazoans on Earth, and represent a unique global source of highly structured and diverse biosilica that has been formed and tested over more than 800 million years of evolution. Poriferans are recognized as a unique archive of siliceous multiscaled skeletal constructs with superficial micro-ornamentat...

How features characteristic of multicellular animals emerged in evolution and how the body plan of particular taxa was shaped are hotspots of modern evolutionary biology. We can get closer to answering them by studying animals that occupy a basal position on the phylogenetic tree, such as sponges (Porifera). We sequenced the genome of the sponge Ha...

Chondrosia reniformis is a collagen-rich marine sponge that is considered a sustainable and viable option for producing an alternative to mammalian-origin collagens. However, there is a lack of knowledge regarding the properties of collagen isolated from different sponge parts, namely the outer region, or cortex, (ectosome) and the inner region (ch...

60-е-80-е годы ХХ столетия очень интересны с точки зрения истории науки, так как именно в это время происходило становление современной био-логии развития. В СССР для биологии этого перио-да характерно значительное отставание в генетиче-ских и молекулярно-биологических исследованиях, что является следствием лысенковского разгрома, технического отст...

The structural biopolymer spongin in the form of a 3D scaffold resembles in shape and size numerous species of industrially useful marine keratosan demosponges. Due to the large-scale aquaculture of these sponges worldwide, it represents a unique renewable source of biological material, which has already been successfully applied in biomedicine and...

In this study, we present the first integrative revision of the Boreal and Arctic calcareous sponges of the genus Leucosolenia with a specific focus on its biodiversity in the White Sea. The material for this work included a combination of newly collected specimens from different regions of the North-East Atlantic and the White Sea and historical m...

Skeletal constructs of diverse marine sponges remain to be a sustainable source of biocompatible porous biopolymer-based 3D scaffolds for tissue engineering and technology, especially structures isolated from cultivated demosponges, which belong to the Verongiida order, due to the renewability of their chitinous, fibre-containing architecture focus...

Marine sponges of the subclass Keratosa originated on our planet about 900 million years ago and represent evolutionarily ancient and hierarchically structured biological materials. One of them, proteinaceous spongin, is responsible for the formation of 3D structured fibrous skeletons and remains enigmatic with complex chemistry. The objective of t...

Currently composed of only one order and two families, the class Homoscleromorpha has undergone significant changes in its systematics over the past 20 years. We combined morphological, cytological and molecular (CO1) data to describe three new aspiculate Homoscleromorpha, two Plakinidae and one Oscarellidae. These three sponges live in the dark su...

Dietary studies are critical for understanding foraging strategies and have important applications in conservation and habitat management. We applied a robust metabarcoding protocol to characterize the diet of the critically endangered freshwater fish Zingel asper (the Rhone streber). We conducted modelling and simulation analyses to characterize a...

The sponge genus Oscarella is very important for the understanding of the early evolution of Metazoa, but the identification of its species is particularly difficult due to the absence of a skeleton and high polymorphism, leading to an underestimate of its diversity. The discovery of nine distinct morphotypes of Oscarella co-existing in cryptic hab...

Niche partitioning studies are essential to understand the mechanisms that allow ecologically similar species to coexist. The Rhone streber (Zingel asper) and the European bullhead (Cottus gobio) are both benthic riverine fishes that consume macroinvertebrates. Both species are protected under European legislature. We focused on trophic niche parti...

Potential for, and limits to, adaptation to environmental changes are critical for resilience and risk mitigation. The Mediterranean basin is a mosaic of biodiversity-rich ecosystems long affected by human influence, whose resilience is now questioned by climate change. After reviewing the different components of biological adaptation, we present t...

Sponges (Porifera), basal nonbilaterian metazoans, are well known for their high regenerative capacities ranging from reparation of a lost body wall to whole-body regeneration from a small piece of tissues or even from dissociated cells. Sponges from different clades utilize different cell sources and various morphological processes to complete the...

Tissues of multicellular animals are maintained due to a tight balance between cell proliferation and programmed cell death. Sponges are early branching metazoans essential to understanding the key mechanisms of tissue homeostasis. This article is dedicated to the comparative analysis of proliferation and apoptosis in intact tissues of two sponges,...

Unlike vertebrates, adult stem cells (ASC) in a wide range of aquatic invertebrate phyla are morphologically diverse, exhibiting a wide range of differentiation states as well as somatic and germline physiognomies. They may arise de novo by trans-differentiation from somatic cells and above all represent phenotypes of specialized cells with multifu...

Sponges (phylum Porifera) are early-branching animals, whose outwardly simple body plan is underlain by a complex genetic repertoire. The transition from a mobile larva to an attached filter-feeding organism occurs by metamorphosis, a process accompanied by a radical change of the body plan and cell transdifferentiation. The continuity between larv...

Carnivorous sponges (family Cladorhizidae) lack the aquiferous system and choanocytes and, therefore, their reproduction and in particular spermatogenesis is unusual for Porifera. We studied spermatogenesis in a carnivorous sponge Lycopodina hypogea using confocal microscopy, SEM and TEM. In brief, spermatogenesis in L. hypogea proceeds as follows....

Actin is a fundamental member of an ancient superfamily of structural intracellular proteins and plays a crucial role in cytoskeleton dynamics, ciliogenesis, phagocytosis, and force generation in both prokaryotes and eukaryotes. It is shown that actin has another function in metazoans: patterning biosilica deposition, a role that has spanned over 5...

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...

Sponges (phylum Porifera) are highly specialized filter-feeding metazoans, pumping and filtering water with a network of canals and chambers, the aquiferous system. Most sponges have a leuconoid aquiferous system, characterized by choanocytes organized in small spherical chambers connected with ambient water by a complex net of canals. Such organiz...

Details of spermatogenesis and sperm organization are often useful for reconstructing the phylogeny of closely related taxa of invertebrates. Here, the spermiogenesis and the ultrastructure of sperm were studied in two marine demosponges, Crellomima imparidens and Hymedesmia irregularis (order Poecilosclerida). In C. imparidens and H. irregularis w...

Although Bonellia viridis is the best studied echiurid species, many features of its anatomy and ultrastructure are still unclear. Detailed data on the organisation of the proboscis may help us to understand the echiurid biology and some aspects of their feeding behaviour. In this study, a detailed description of the proboscis epithelium of females...

Background Tissues of multicellular animals are maintained due to a tight balance between cell proliferation and programmed cell death. Phylum Porifera is an early branching group of metazoans essential to understanding the key mechanisms of tissue homeostasis. This paper is dedicated to the comparative analysis of proliferation and apoptosis in in...

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. Such ASCs are mostly rare, morphologically undifferentiated, and undergo asymmetric cell division. Characterized b...

The morphological investigation of the larval development in a White-Sea sponge, Iophon piceus (Vosmaer, 1882) (the family Myxillidae), was carried out. The differentiation of larval structures begins with the morula stage. The larval surface epithelium develops from the embryo peripheral cells. Numerous folds of epithelium are formed during the la...

Background The ability to regenerate lost or damaged body parts is an ancient animal characteristic with a wide yet variable distribution across all phyla. Sponges, likely the sister group to all other animals, have remarkable regenerative abilities including whole body regeneration and re-development from dissociated cells. The calcareous sponge S...

The phenomenon of whole-body regeneration means rebuilding of the whole body of an animal from a small fragment or even a group of cells. In this process, the old axial relationships are often lost, and new ones are established. An amazing model for studying this process is sponges, some of which are able to regenerate into a definitive organism af...

Porifera, commonly named sponges, are devoid of head, digestive tract, nervous system, muscles or any other organs. Despite this anatomical and morphological simplicity, they are true animals or metazoans. Sponges are a successful group of mostly marine filter feeders that represent a major life form of several aquatic ecosystems. Efficient water f...

Alexander O. Kowalevsky (1840–1901), a founder of cellular and comparative evolutionary embryology, was one of the most prominent biologists of the nineteenth century. He worked at the intersection of zoology, embryology, and evolution. His studies on the lancelet, tunicates, insects, and germ layer homologies pioneered comparative embryology and c...

While virtually all animals show certain abilities for regeneration after an injury, these abilities vary greatly among metazoans. Porifera (Sponges) is basal metazoans characterized by a wide variety of different regenerative processes, including whole-body regeneration (WBR). Considering phylogenetic position and unique body organization, sponges...

Sponges (Porifera) belong to an ancient metazoan lineage that represents one of the earliest branches of the animal tree. The superficial region of the sponge body is devoid of choanocyte chambers (which are a component of the aquiferous system) and referred to as the ectosome. Sponges from classes Calcarea, Demospongiae, and Homoscleromorpha have...

Dietary studies are critical for understanding foraging strategies and have important applications in conservation and habitat management. We applied a robust metabarcoding protocol to characterize the diet of the critically endangered freshwater fish Zingel asper and conducted modelling and simulation analyses to characterize and identify some of...

Spicules are mineral-based biocomposites skeletal structures that are widely distributed among phylogenetically distant groups of invertebrates (Porifera, Cnidaria, Mollusca, Echinodermata). Subepidermal spicules are formed under the ectodermal epithelium and are characterized for all groups except mollusks (Aplacophora, Polyplacophora, Bivalvia),...

The structure of the kinetid (flagellar or ciliary apparatus) is known to be of phylogenetic significance in sponges (Phylum Porifera) and can provide information about evolutionary relationships. Here, we report on the larval kinetid structure of two closely related species, Oscarella lobularis and O. tuberculata (Homoscleromorpha, Oscarellidae)....

Homoscleromorpha is a recently recognized class within the phylum Porifera. While molecular analyses support monophyly of Homoscleromorpha, morphological data are largely lacking. Here, we investigate and comparatively analyze the detailed morphology of kinetids (flagellar apparatus) in choanocytes of ten Oscarella species. The kinetid is known to...

[Full text here: https://rdcu.be/b7qrv] The kinetid (flagellar/ciliary apparatus) of eukaryotic cells is an important source of phylogenetic information. It was found to be a prospective morphological phylogenetic marker in sponges, since its arrangement in choanocytes is congruent with the topology of the phylogenetic trees. However, investigation...

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 mole...

Although Arctic communities are very sensitive to global warming, direct evidence of the effects of high temperature on bottom communities is quite rare. We observed a mass mortality event (MME) of sponges by SCUBA diving in July and August 2018 along the coasts of Kandalaksha Bay, White Sea, and sub-Arctic. This event severely affected sponges fro...

Fabrication of biomimetic materials and scaffolds is usually a micro- or even nanoscale process; however, most testing and all manufacturing require larger-scale synthesis of nanoscale features. Here, we propose the utilization of naturally prefabricated three-dimensional (3D) spongin scaffolds that preserve molecular detail across centimeter-scale...

[Full text here: https://rdcu.be/bntId] At larval and adult stage of life cycle, sponges (Porifera) have different flagellated cells that play different roles in their body. The larval epithelium cells serve as locomotion organs, while adult collar cells (choanocytes) have a feeding function. Here, for the first time, we describe detailed structure...

The genus Hemimysis (Malacostraca: Mysida: Mysidae) encompasses near-bottom, demersal and cave-dwelling mysids living in the marine, brackish and freshwater habitats around the European coast, from the Caspian Sea to the Scandinavian Peninsula. We conducted cladistic analysis of 52 morphological characters of all nine species and three subspecies o...

Sponges (Porifera) represent one of the most ancient metazoan lineages. They possess unique anatomical and tissue structure, making them promising models for evolutionary studies. The high plasticity of sponge tissue and cells provide them with outstanding recovery abilities, ranging from wound healing to re-building of a functional body from disso...

The spermatogenesis of Porifera is still relatively poorly understood. In the past, it was accepted that all species presented a primitive-type spermatozoon, lacking special structures and acrosome. Nonetheless, a very peculiar spermatogenesis resulting in a sophisticated V-shaped spermatozoon with an acrosome was found in Poecilosclerida. This fin...

Sponges are a valuable source of natural compounds and biomaterials for many biotechnological applications. Marine sponges belonging to the order Verongiida are known to contain both chitin and biologically active bromotyrosines. Aplysina archeri (Aplysineidae: Verongiida) is well known to contain bromotyrosines with relevant bioactivity against hu...

Cell-to-cell signaling is responsible for regulation of many developmental processes such as proliferation, cell migration, survival, cell fate specification and axis patterning. In this article we discussed the role of signaling in the metamorphosis of sponges with a focus on epithelial–mesenchymal transition (EMT) accompanying this event. Sponges...

Sponges are the most ancient multicellular animals. They demonstrate broad recovery abilities after various wounds, and due to their phylogenetic position, studies of repair processes in sponges are required for understanding the evolution of the regeneration mechanisms in animals. We studied the reparative regeneration in two widely distributed sp...

Porifera represents one of the most diverse taxon of sessile invertebrates with over 9 000 extant species. Calcareous sponges of the genus Leucosolenia are an emerging model object for evolutionary developmental biology studies. However, recent studies on the class Calcarea, and in particular on the subclass Calcaronea, indicates the presence of hi...

Sponges (Porifera) demonstrate prominent regeneration abilities and possess a wide variety of mechanisms, used during this process. In the current study, we combined in vivo observations with histological, immunohistochemical, and ultrastructural technics to elucidate the fine cellular mechanisms of the regeneration in the calcareous sponge Leucoso...

VideoS1. The growth of the regenerative membrane during the oscular regeneration of Leucosolenia cf. variabilis. Stopwatch indicates hours, minutes and seconds. Red arrows mark the position of the regenerative membrane internal rim, white cycle – the moment and position of the regenerative membrane closure. rm – regenerative membrane; we – wound ed...

Supplemental Figure 1. In vivo images of Leucosolenia cf. variabilis body wall regeneration. A – just after surgical operation. B – 10 hours post operation (hpo). C – regenerative membrane formation (24 hpo). D – beginning of new spicule formation in the regenerative membrane (48 hpo). E – beginning of normal body wall restoration (96 hpo). F – end...

The Mediterranean basin is a region of high biodiversity, marine and terrestrial, with important endemism. This diversity has faced long-lasting, strong and increasing human demographic pressure. The relatively more recent effects of climate change are well visible in the Mediterranean basin, with for example, heat wave and summer-drought related m...

Sponges are the earliest branching metazoans, and as such a key group for understanding of the evolutionary history of animal regeneration mechanisms. Sponges are known to possess remarkable reconstitutive and regenerative abilities. We investigated regeneration of Leucosolenia complicata, an abundant and broadly distributed in White Sea species. W...

Marine caves possess unique biocoenotic and ecological characteristics. Sessile benthic species such as sponges associated with cave habitats typically show a marked zonation from the cave entrance towards the end of the cave. We describe three semi-submerged karstic caves of 50 to 83 m length and 936 to 2,291 m3 volume from the poorly explored cav...