Archaeocytes in sponges: simple cells of complicated fate.

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.

Cell cycle dynamics of food-entrapping cells of sponges: an experimental approach.

Sponges (phylum Porifera) exhibit surprisingly complex tissue dynamics, maintaining constant cell turnover and migration, rearranging internal structures, and regenerating after severe injuries. Such tissue plasticity relies on the activity of proliferating cells represented primarily by the food-entrapping cells, choanocytes. Although there are plenty of studies regarding the dynamics of regeneration and tissue rearrangement in sponges, cell cycle kinetics of choanocytes in intact tissues remains a controversial issue.

Regeneration in calcareous sponge relies on 'purse-string' mechanism and the rearrangements of actin cytoskeleton.

The crucial step in any regeneration process is epithelization, i.e. the restoration of an epithelium structural and functional integrity.

Tissue homeostasis in sponges: Quantitative analysis of cell proliferation and apoptosis.

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, Halisarca dujardinii (class Demospongiae) and Leucosolenia variabilis (class Calcarea).

Studying Porifera WBR Using the Calcerous Sponges Leucosolenia.

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 regeneration. This variety makes these animals promising models for studying the evolution of regeneration in Metazoa.

Novel protein from larval sponge cells, ilborin, is related to energy turnover and calcium binding and is conserved among marine invertebrates.

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 larval cells and adult tissues is still obscure.

Fine details of the choanocyte filter apparatus in asconoid calcareous sponges (Porifera: Calcarea) revealed by ruthenium red fixation.

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 organization requires substantial pressure difference to drive water through an elaborate system of canals, so the choanocytes in leuconoid sponges have several structural features to generate pressure difference.

Expression of Wnt and TGF-Beta Pathway Components during Whole-Body Regeneration from Cell Aggregates in Demosponge .

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 after dissociation into cells.

Whole-Body Regeneration in Sponges: Diversity, Fine Mechanisms, and Future Prospects.

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 are highly promising models, as they can shed light on the origin and early evolution of regeneration in general and WBR in particular.

Intraspecific variability of cell reaggregation during reproduction cycle in sponges.

The ability of sponge cells to reaggregate and reconstruct intact functional organism is known for more than 100 years. This process was studied in numerous species of sponges, and its interspecific variability is well described. However, some data also indicate the existence of a certain intraspecific variability of the cell reaggregation.

Transdifferentiation and mesenchymal-to-epithelial transition during regeneration in Demospongiae (Porifera).

Origin and early evolution of regeneration mechanisms remain among the most pressing questions in animal regeneration biology. Porifera have exceptional regenerative capacities and, as early Metazoan lineage, are a promising model for studying evolutionary aspects of regeneration. Here, we focus on reparative regeneration of the body wall in the Mediterranean demosponge Aplysina cavernicola.

Sewing up the wounds : The epithelial morphogenesis as a central mechanism of calcaronean sponge regeneration.

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 Leucosolenia cf. variabilis.

Stolonial Movement: A New Type of Whole-Organism Behavior in Porifera.

Sponges (phylum Porifera) traditionally are represented as inactive, sessile filter-feeding animals devoid of any behavior except filtering activity. However, different time-lapse techniques demonstrate that sponges are able to show a wide range of coordinated but slow whole-organism behavior. The present study concerns a peculiar type of such behavior in the psychrophilic demosponge Amphilectus lobatus: stolonial movement.

Proteomics of the 26S proteasome in Spodoptera frugiperda cells infected with the nucleopolyhedrovirus, AcMNPV.

Baculoviruses are large DNA viruses that infect insect species such as Lepidoptera and are used in biotechnology for protein production and in agriculture as insecticides against crop pests. Baculoviruses require activity of host proteasomes for efficient reproduction, but how they control the cellular proteome and interact with the ubiquitin proteasome system (UPS) of infected cells remains unknown. In this report, we analyzed possible changes in the subunit composition of 26S proteasomes of the fall armyworm, Spodoptera frugiperda (Sf9), cells in the course of infection with the Autographa californica multiple nucleopolyhedrovirus (AcMNPV).

Sponge cell reaggregation: Cellular structure and morphogenetic potencies of multicellular aggregates.

Sponges (phylum Porifera) are one of the most ancient extant multicellular animals and can provide valuable insights into origin and early evolution of Metazoa. High plasticity of cell differentiations and anatomical structure is characteristic feature of sponges. Present study deals with sponge cell reaggregation after dissociation as the most outstanding case of sponge plasticity.

Egress of budded virions of Autographa californica nucleopolyhedrovirus does not require activity of Spodoptera frugiperda HSP/HSC70 chaperones.

The induction of heat shock proteins in baculovirus infected cells is well documented. However a role of these chaperones in infection cycle remains unknown. The observation that HSP70s are associated with virions of different baculoviruses reported by several researchers suggests that HSPs might be structural components of viruses or involved in virion assembly.