Primmorphs from archaeocytes-dominant cell population of the sponge hymeniacidon perleve: improved cell proliferation and spiculogenesis

Deep-Sea Sponges and Corals off the Western Coast of Florida-Intracellular Mechanisms of Action of Bioactive Compounds and Technological Advances Supporting the Drug Discovery Pipeline

The majority of natural products utilized to treat a diverse array of human conditions and diseases are derived from terrestrial sources. In recent years, marine ecosystems have proven to be a valuable resource of diverse natural products that are generated to defend and support their growth. Such marine sources offer a large opportunity for the identification of novel compounds that may guide the future development of new drugs and therapies. Using the National Oceanic and Atmospheric Administration (NOAA) portal, we explore deep-sea coral and sponge species inhabiting a segment of the U.S. Exclusive Economic Zone, specifically off the western coast of Florida. This area spans ~100,000 km2, containing coral and sponge species at sea depths up to 3000 m. Utilizing PubMed, we uncovered current knowledge on and gaps across a subset of these sessile organisms with regards to their natural products and mechanisms of altering cytoskeleton, protein trafficking, and signaling pathways. Since the exploitation of such marine organisms could disrupt the marine ecosystem leading to supply issues that would limit the quantities of bioactive compounds, we surveyed methods and technological advances that are necessary for sustaining the drug discovery pipeline including in vitro aquaculture systems and preserving our natural ecological community in the future. Collectively, our efforts establish the foundation for supporting future research on the identification of marine-based natural products and their mechanism of action to develop novel drugs and therapies for improving treatment regimens of human conditions and diseases.

On the origin of the functional versatility of macrophages

Macrophages represent the most functionally versatile cells in the animal body. In addition to recognizing and destroying pathogens, macrophages remove senescent and exhausted cells, promote wound healing, and govern tissue and metabolic homeostasis. In addition, many specialized populations of tissue-resident macrophages exhibit highly specialized functions essential for the function of specific organs. Sometimes, however, macrophages cease to perform their protective function and their seemingly incomprehensible response to certain stimuli leads to pathology. In this study, we address the question of the origin of the functional versatility of macrophages. To this end, we have searched for the evolutionary origin of macrophages themselves and for the emergence of their characteristic properties. We hypothesize that many of the characteristic features of proinflammatory macrophages evolved in the unicellular ancestors of animals, and that the functional repertoire of macrophage-like amoebocytes further expanded with the evolution of multicellularity and the increasing complexity of tissues and organ systems. We suggest that the entire repertoire of macrophage functions evolved by repurposing and diversification of basic functions that evolved early in the evolution of metazoans under conditions barely comparable to that in tissues of multicellular organisms. We believe that by applying this perspective, we may find an explanation for the otherwise counterintuitive behavior of macrophages in many human pathologies.

Meta-transcriptomic comparison of two sponge holobionts feeding on coral- and macroalgal-dissolved organic matter

Background

Sponge holobionts (i.e., the host and its associated microbiota) play a key role in the cycling of dissolved organic matter (DOM) in marine ecosystems. On coral reefs, an ecological shift from coral-dominated to algal-dominated ecosystems is currently occurring. Given that benthic corals and macroalgae release different types of DOM, in different abundances and with different bioavailability to sponge holobionts, it is important to understand how the metabolic activity of the host and associated microbiota change in response to the exposure to both DOM sources. Here, we look at the differential gene expression of two sponge holobionts 6 hours after feeding on naturally sourced coral- and macroalgal-DOM using RNA sequencing and meta-transcriptomic analysis.

Results

We found a slight, but significant differential gene expression in the comparison between the coral- and macroalgal-DOM treatments in both the high microbial abundance sponge Plakortis angulospiculatus and the low microbial abundance sponge Haliclona vansoesti. In the hosts, processes that regulate immune response, signal transduction, and metabolic pathways related to cell proliferation were elicited. In the associated microbiota carbohydrate metabolism was upregulated in both treatments, but coral-DOM induced further lipid and amino acids biosynthesis, while macroalgal-DOM caused a stress response. These differences could be driven by the presence of distinct organic macronutrients in the two DOM sources and of small pathogens or bacterial virulence factors in the macroalgal-DOM.

Conclusions

This work provides two new sponge meta-transcriptomes and a database of putative genes and genetic pathways that are involved in the differential processing of coral- versus macroalgal-DOM as food source to sponges with high and low abundances of associated microbes. These pathways include carbohydrate metabolism, signaling pathways, and immune responses. However, the differences in the meta-transcriptomic responses of the sponge holobionts after 6 hours of feeding on the two DOM sources were small. Longer-term responses to both DOM sources should be assessed to evaluate how the metabolism and the ecological function of sponges will be affected when reefs shift from coral towards algal dominance.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08893-y.

Marine Sponge Endosymbionts: Structural and Functional Specificity of the Microbiome within Euryspongia arenaria Cells

Sponge microbiomes are typically profiled by analyzing the community DNA of whole tissues, which does not distinguish the taxa residing within sponge cells from extracellular microbes. To uncover the endosymbiotic microbiome, we separated the sponge cells to enrich the intracellular microbes. The intracellular bacterial community of sponge Euryspongia arenaria was initially assessed by amplicon sequencing, which indicated that it hosts three unique phyla not found in the extracellular and bulk tissue microbiomes. These three phyla account for 66% of the taxonomically known genera in the intracellular microbiome. The shotgun metagenomic analysis extended the taxonomic coverage to viruses and eukaryotes, revealing the most abundant signature taxa specific to the intracellular microbiome. Functional KEGG pathway annotation demonstrated that the endosymbiotic microbiome hosted the greatest number of unique gene orthologs. The pathway profiles distinguished the intra- and extracellular microbiomes from the tissue and seawater microbiomes. Carbohydrate-active enzyme analysis further discriminated each microbiome based on their representative and dominant enzyme families. One pathway involved in digestion system and family esterase had a consistently higher level in intracellular microbiome and could statistically differentiate the intracellular microbiome from the others, suggesting that triacylglycerol lipases could be the key functional component peculiar to the endosymbionts. The identified higher abundance of lipase-related eggNOG categories further supported the lipid-hydrolyzing metabolism of endosymbiotic microbiota. Pseudomonas members, reported as lipase-producing bacteria, were only in the endosymbiotic microbiome, meanwhile Pseudomonas also showed a greater abundance intracellularly. Our study aided a comprehensive sponge microbiome that demonstrated the taxonomic and functional specificity of endosymbiotic microbiota.

IMPORTANCE Sponges host abundant microbial symbionts that can produce an impressive number of novel bioactive metabolites. However, knowledge on intracellular (endosymbiotic) microbiota is scarce. We characterize the composition and function of the endosymbiotic microbiome by separation of sponge cells and enrichment of intracellular microbes. We uncover a noteworthy number of taxa exclusively in the endosymbiotic microbiome. We unlock the unique pathways and enzymes of endosymbiotic taxa. This study achieves a more comprehensive sponge microbial community profile, which demonstrates the structural and functional specificity of the endosymbiotic microbiome. Our findings not only open the possibility to reveal the low abundant and the likely missed microbiota when directly sequencing the sponge bulk tissues, but also warrant future in-depth exploration within single sponge cells.

Cultivation of fractionated cells from a bioactive-alkaloid-bearing marine sponge Axinella sp

Sponges are among the most primitive multicellular organisms and well-known as a major source of marine natural products. Cultivation of sponge cells has long been an attractive topic due to the prominent evolutionary and cytological significance of sponges and as a potential approach to supply sponge-derived compounds. Sponge cell culture is carried out through culturing organized cell aggregates called 'primmorphs.' Most research culturing sponge cells has used unfractionated cells to develop primmorphs. In the current study, a tropical marine sponge Axinella sp., which contains the bioactive alkaloids, debromohymenialdisine (DBH), and hymenialdisine (HD), was used to obtain fractionated cells and the corresponding primmorphs. These alkaloids, DBH and HD, reportedly show pharmacological activities for treating osteoarthritis and Alzheimer's disease. Three different cell fractions were obtained, including enriched spherulous cells, large mesohyl cells, and small epithelial cells. These cell fractions were cultivated separately, forming aggregates that later developed into different kinds of primmorphs. The three kinds of primmorphs obtained were compared as regards to appearance, morphogenesis, and cellular composition. Additionally, the amount of alkaloid in the primmorphs-culture system was examined over a 30-d culturing period. During the culturing of enriched spherulous cells and developed primmorphs, the total amount of alkaloid declined notably. In addition, the speculation of alkaloid secretion and some phenomena that occurred during cell culturing are discussed.

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. The present review summarizes available data on the morphogenetic and cellular mechanisms accompanying different types of WBR in sponges. Sponges show a high diversity of WBR, which principally could be divided into (1) WBR from a body fragment and (2) WBR by aggregation of dissociated cells. Sponges belonging to different phylogenetic clades and even to different species and/or differing in the anatomical structure undergo different morphogeneses after similar operations. A common characteristic feature of WBR in sponges is the instability of the main body axis: a change of the organism polarity is described during all types of WBR. The cellular mechanisms of WBR are different across sponge classes, while cell dedifferentiations and transdifferentiations are involved in regeneration processes in all sponges. Data considering molecular regulation of WBR in sponges are extremely scarce. However, the possibility to achieve various types of WBR ensured by common morphogenetic and cellular basis in a single species makes sponges highly accessible for future comprehensive physiological, biochemical, and molecular studies of regeneration processes.

Development of cultures of the marine sponge Hymeniacidon perleve for genotoxicity assessment using the alkaline comet assay

Sponges are a potential alternative model species to bivalves in pollution biomonitoring and environmental risk assessment in the aquatic ecosystem. In the present study, a novel in vivo exposure sponge culture model was developed from field-collected and cryopreserved sponge (Hymeniacidon perleve) cells to investigate the genotoxic effects of environmentally relevant metals in the laboratory. Sponge cell aggregates were cultured and exposed to noncytotoxic concentrations (0-0.4 mg/L) of cadmium chloride, nickel chloride, and sodium dichromate as quantified by the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and DNA-strand breaks assessed by the comet assay. Reactive oxygen species (ROS) formation was quantified by oxidation of 2',7'-dichlorofluorescin diacetate in sponge cell aggregates exposed to the same concentrations of Cd, Cr, and Ni. There was a statistically significant (p < 0.05) concentration-dependent increase in the level of DNA-strand breaks and ROS formation in all of the metals investigated. To the best of our knowledge, we have utilized for the first time the alkaline comet assay to detect DNA-strand breaks in marine sponge cells and demonstrated that exposure to noncytotoxic concentrations of Cd, Cr, and Ni for 12 h results in a concentration-dependent increase in DNA damage and levels of ROS production. In conclusion, we have developed a novel in vivo model based on culture of cryopreserved sponge cells that is compatible with the alkaline comet assay. Genotoxicity in marine sponges measured by the comet assay technique may be a useful tool for biomonitoring research and risk assessment in aquatic ecosystems. Environ Toxicol Chem 2017;36:3314-3323. © 2017 SETAC.

MicroRNA expression during demosponge dissociation, reaggregation, and differentiation and a evolutionarily conserved demosponge miRNA expression profile

Demosponges share eight orthologous microRNAs (miRNAs), with none in common with Bilateria. Biological functions of these demosponge miRNAs are unknown. Bilaterian miRNAs are key regulators of cellular processes including cell cycle, differentiation, and metabolism. Resolving if demosponge miRNAs participate in such biological functions will provide clues whether these functions are convergent, evidence on the mode of evolution of cellular developmental processes. Here, a quantitative PCR (qPCR) assay was developed and used to test for differential miRNA expression during dissociation and reaggregation in Spongosorites, compare expression profiles between choanosome and cortex in Spongosorites, and compare undifferentiated gemmules to differentiated juveniles in Ephydatia. During Spongosorites dissociation and reaggregation, miRNA expression showed a global decrease in expression across a range of reaggregating cell densities. miRNA differential response could be related to various general cellular responses, potentially related to nutrient-poor conditions of the minimal artificial seawater media, stress response from tissue dissociation, or loss of cell-cell or cell-matrix contact. In Ephydatia, overall increase in miRNA expression in gemmule-hatched stage 4/5 juveniles relative to gemmules is observed, indicating that increased miRNA expression may be related to increased cellular activity such as migration, cell cycle, and/or differentiation. Observed differential miRNA expression of miRNA during dissociation in Spongosorites (lowered global expression), and during activation, and differentiation of Ephydatia gemmules (increased global expression) could indicate that miRNA expression is associated with cell cycle, differentiation, or metabolism pathways. Interspecies comparison was performed, results indicating that orthologous miRNAs share similar relative expression pattern between the four species tested (Spongosorites, Cinachyrella, Haliclona, and Ephydatia), demonstrating and evolutionarily conserved miRNA expression profile across Demospongia. While these results do not elucidate specific molecular and cellular pathways, together they provide a broad survey of miRNA expression in demosponge systems.

Phagocytic efficiency and cytotoxic responses of Indian freshwater sponge (Eunapius carteri) cells isolated by density gradient centrifugation and flow cytometry: a morphofunctional analysis

The freshwater sponge Eunapius carteri (Porifera: Demospongiae: Spongillidae), a resident of Indian freshwater ecosystems, has pharmaceutical and ecological potential, but there is inadequate information on its cellular spectrum and cell-mediated immune responses. Microscopical analysis revealed the existence of eight distinct cellular variants, i.e. blast-like cells, choanocytes, small amoebocytes, granular cells, pinacocytes, large amoebocytes, archaeocytes and sclerocytes. The cells were isolated by density gradient centrifugation and flow cytometry and used for a morphofunctional analysis. We investigated the phagocytic efficiency of E. carteri cells under the challenge of yeast particles in vitro and spectrophotometrically quantified the generation of cytotoxic molecules (superoxide anions and nitric oxide) in different isolated cellular fractions. The two cell separating technologies did not yield any significant differences in the major findings on morphology, phagocytic response and generation of superoxide anions and nitric oxide. Archaeocytes, granular cells and large amoebocytes were identified as chief phagocytes with a high phagocytic potential as recorded by light microscopy. Archaeocytes were the principal generators of superoxide anions, whereas nitric oxide was recorded in the fractions rich in archaeocytes and large amoebocytes. The present investigation thus provides useful information regarding cellular variation, cytotoxic status and innate phagocytic response of the cells of E. carteri, a common but less studied sponge of India.

Marine sponge derived natural products between 2001 and 2010: trends and opportunities for discovery of bioactives

Marine sponges belonging to the phylum Porifera (Metazoa), evolutionarily the oldest animals are the single best source of marine natural products. The present review presents a comprehensive overview of the source, taxonomy, country of origin or geographical position, chemical class, and biological activity of sponge-derived new natural products discovered between 2001 and 2010. The data has been analyzed with a view to gaining an outlook on the future trends and opportunities in the search for new compounds and their sources from marine sponges.

Primmorphs cryopreservation: a new method for long-time storage of sponge cells

The possibility to cryopreserve cells allows for wide opportunities of flexible handling of cell cultures from different sponge species. Primmorphs model, a multicellular 3D aggregate formed by dissociated sponge cells, is considered one of the best approaches to establish sponge cell culture but, in spite of the available protocols for freezing sponge cells, there is no information regarding the ability of the latter to form primmorphs after thawing. In the present work, we demonstrate that, after a freezing and thawing cycle using dissociated Petrosia ficiformis cells as a model, cells viability was high but it was not possible to obtain primmorphs. The same protocol for cryopreservation was then used to directly freeze primmorphs. In this second case, after thawing, viability and the cellular proliferative level were similar to unfrozen standard primmorphs. Spiculogenesis in thawed primmorphs was evaluated by quantifying the silicatein gene expression level and by assaying the silica amount in the newly formed spicules, then compared with the correspondent values obtained in standard unfrozen primmorphs. Results indicate that the freezing cycle does not affect the spiculogenesis rate. Finally, the expression level of heat shock protein 70, a well-known stress marker, was assayed and the results showed no differences between frozen and unfrozen samples. These findings are likely to promote relevant improvements in sponge cell culture technique, allowing for a worldwide exchange of living biological material, paving the way for cell banking of Porifera.

Cultivation of sponges, sponge cells and symbionts: achievements and future prospects

Marine sponges are a rich source of bioactive compounds with pharmaceutical potential. Since biological production is one option to supply materials for early drug development, the main challenge is to establish generic techniques for small-scale production of marine organisms. We analysed the state of the art for cultivation of whole sponges, sponge cells and sponge symbionts. To date, cultivation of whole sponges has been most successful in situ; however, optimal conditions are species specific. The establishment of sponge cell lines has been limited by the inability to obtain an axenic inoculum as well as the lack of knowledge on nutritional requirements in vitro. Approaches to overcome these bottlenecks, including transformation of sponge cells and using media based on yolk, are elaborated. Although a number of bioactive metabolite-producing microorganisms have been isolated from sponges, and it has been suggested that the source of most sponge-derived bioactive compounds is microbial symbionts, cultivation of sponge-specific microorganisms has had limited success. The current genomics revolution provides novel approaches to cultivate these microorganisms.

Examination of marine-based cultivation of three demosponges for acquiring bioactive marine natural products

Marine sponges are an extremely rich and important source of natural products. Mariculture is one solution to the so-called "supply problem" that often hampers further studies and development of novel compounds from sponges. We report the extended culture (767 days) at sea in depths of 10 and 20 m of three sponge species: Negombata magnifica, Amphimedon chloros and Theonella swinhoei that produce latrunculin-B, halitoxin and swinholide-A, respectively. Since sponge-associated microorganisms may be the true producers of many of the natural products found in sponges and also be linked to the health of the sponges, we examined the stability of the bacterial communities in cultured versus wild sponges. Growth rate of the sponges (ranging from 308 to 61 and -19 (%)(year(-1)) in N. magnifica, A. chloros and T. swinhoei, respectively) differed significantly between species but not between the two depths at which the species were cultivated. Survivorship varied from 96% to 57%. During culture all species maintained the content of the desired natural product. Denaturing gradient gel electrophoresis analysis of the sponge-associated bacterial consortia revealed that differences existed between cultured and wild sponges in T. swinhoei and A. chloros but the communities remained quite stable in N. magnifica. The cultivation technique for production of natural products was found to be most appropriate for N. magnifica, while for T. swinhoei and A. chloros it was less successful, because of poorer growth and survival rates and shifts in their bacterial consortia.

Cellular localization of debromohymenialdisine and hymenialdisine in the marine sponge Axinella sp. using a newly developed cell purification protocol

Sponges (Porifera), as the best known source of bioactive marine natural products in metazoans, play a significant role in marine drug discovery and development. As sessile filter-feeding animals, a considerable portion of the sponge biomass can be made of endosymbiotic and associated microorganisms. Understanding the cellular origin of targeted bioactive compounds from sponges is therefore important not only for providing chemotaxonomic information but also for defining the bioactive production strategy in terms of sponge aquaculture, cell culture, or fermentation of associated bacteria. The two alkaloids debromohymenialdisine (DBH) and hymenialdisine (HD), which are cyclin-dependent kinase inhibitors with pharmacological activities for treating osteoarthritis and Alzheimer's disease, have been isolated from the sponge Axinella sp. In this study, the cellular localization of these two alkaloids was determined through the quantification of these alkaloids in different cell fractions by high-performance liquid chromatography (HPLC). First, using a differential centrifugation method, the dissociated cells were separated into different groups according to their sizes. The two bioactive alkaloids were mainly found in sponge cells obtained from low-speed centrifugation. Further cell purifications were accomplished by a newly developed multi-step protocol. Four enriched cell fractions (C1, C2, C3, and C4) were obtained and subjected to light and transmission electron microscopy, cytochemical staining, and HPLC quantification. Compared to the low concentrations in other cell fractions, DBH and HD accounted for 10.9% and 6.1%, respectively, of dry weight in the C1 fraction. Using the morphological characteristics and cytochemical staining results, cells in the C1 fraction were speculated to be spherulous cells. This result shows that DBH and HD in Axinella sp. are located in sponge cells and mostly stored in spherulous cells.

Long-term cultivation of primmorphs from freshwater Baikal sponges Lubomirskia baikalensis

The work was aimed at performing long-term cultivation of primmorphs in vitro from freshwater sponge Lubomirskia baikalensis (Pallas 1776), collected from Lake Baikal, obtaining its long-term primmorph culture in both natural (NBW) and artificial (ABW) Baikal water and at identifying the impact of different environmental factors on formation and growth of primmorphs. The first fine aggregates of L. baikalensis are formed in vitro 10-15 min after dissociation of sponge cells. Epithelization of aggregates begins 4 h later after the dissociation. Young primmorphs are formed 1 or 2 days later. The surface of primmorphs is covered with a layer of exopinacocytes. The primmorphs remain viable for more than 10 months at 3-6 °C. Over 50% of primmorphs in NBW and 25% in ABW are attached to the substrate and grow like adult sponges. Thus, the long-term primmorph cultivation in vitro allows the creation of a controlled live model system under experimental conditions. The results of this work will allow the creation of a cell culture collection of Baikal freshwater sponges for studying morphogenesis of primmorphs during cultivation at different stages and transdifferentiation of their cells, physiological functions of sponge cells, processes of spiculogenesis, identification of proteins involved in biomineralization process, decoding of their genes, as well as a spectrum of secondary metabolites.

Influence of rocky substrata on three-dimensional sponge cells model development

Many marine and freshwater organisms are rocky bottom dwellers, and the mineralogical composition of the substratum is known to potentially condition their biology and ecology. In this work, we propose the use of 3D sponge cellular aggregates, called primmorphs, as suitable models for a multidisciplinary study of the mechanisms which regulate the biological responses triggered by the contact with different inorganic substrata. In our experiments, primmorphs obtained from the marine sponge Petrosia ficiformis (Poiret, 1789) were reared on calcium carbonate or on quartzitic substrata, respectively, and their morphological development was described. In parallel, the quantitative expression levels of two genes, silicatein and heat shock protein 70 (HSP70), were evaluated. The first gene is strictly correlated to spiculogenesis and sponge growth, while the second is an important indicator of stress. The results achieved with this in vitro model clearly demonstrate that quartzitic substrata determine the increase of silicatein gene expression, a lower expression of HSP70 gene, and a remarkable difference in primmorphs morphology compared to the analogous samples grown on marble.

Possible taxonomic trends in the success of primary aggregate formation in marine sponge cell cultures

A large number of novel compounds with significant medical potential have been isolated from sponges, motivating efforts to develop techniques for the sustainable cultivation of sponge biomass. To date, 33 sponges from nine different orders have been examined to assess their ability to be cultured in vitro. However, little consideration has been given to the relationships between these sponges; only one report has considering the phylogenetic relationships between the species. On the basis of morphological data, no taxonomic specificity was apparent as an indicator for the successful cultivation of the sponges. As the systematic classification of the Demospongiae is poorly understood, we collated available information on the success of in vitro sponge cell cultivation reports and examined the phylogenetic relationships of these sponges through the use of 18S and 28S rDNA sequence data. Based on molecular data, the ability of sponges to form primary aggregates from the dissociated cells of marine demosponges indicates that taxonomic trends may exist, emphasizing the need to better characterize sponges being investigated for biotechnological applications.

Changes in bacterial communities of the marine sponge Mycale laxissima on transfer into aquaculture

The changes in bacterial communities associated with the marine sponge Mycale laxissima on transfer to aquaculture were studied using culture-based and molecular techniques. M. laxissima was maintained alive in flowthrough and closed recirculating aquaculture systems for 2 years and 1 year, respectively. The bacterial communities associated with wild and aquacultured sponges, as well as the surrounding water, were assessed using 16S rRNA gene clone library analysis and denaturing gradient gel electrophoresis (DGGE). Bacterial richness and diversity were measured using DOTUR computer software, and clone libraries were compared using S-LIBSHUFF. DGGE analysis revealed that the diversity of the bacterial community of M. laxissima increased when sponges were maintained in aquaculture and that bacterial communities associated with wild and aquacultured M. laxissima were markedly different than those of the corresponding surrounding water. Clone libraries of bacterial 16S rRNA from sponges confirmed that the bacterial communities changed during aquaculture. These communities were significantly different than those of seawater and aquarium water. The diversity of bacterial communities associated with M. laxissima increased significantly in aquaculture. Our work shows that it is important to monitor changes in bacterial communities when examining the feasibility of growing sponges in aquaculture systems because these communities may change. This could have implications for the health of sponges or for the production of bioactive compounds by sponges in cases where these compounds are produced by symbiotic bacteria rather than by the sponges themselves.

Cultivation of sponge larvae: settlement, survival, and growth of juveniles

The aim of this study was to culture sponge juveniles from larvae. Starting from larvae we expected to enhance the survival and growth, and to decrease the variation in these parameters during the sponge cultures. First, settlement success, morphological changes during metamorphosis, and survival of Dysidea avara, Ircinia oros, Hippospongia communis, under the same culture conditions, were compared. In a second step, we tested the effects of flow and food on survival and growth of juveniles from Dysidea avara and Crambe crambe. Finally, in a third experiment, we monitored survival and growth of juveniles of D. avara and C. crambe transplanted to the sea to compare laboratory and field results. The results altogether indicated that sponge culture from larvae is a promising method for sponge supply and that laboratory culture under controlled conditions is preferred over sea cultures in order to prevent biomass losses during these early life stages.

Dynamics of spicule production in the marine sponge Hymeniacidon perlevis during in vitro cell culture and seasonal development in the field

To characterize the formation of silica spicules, the dynamics of spiculogenesis of an intertidal marine sponge Hymeniacidon perlevis (Montagu 1818) (Porifera: Demospongiae) were investigated by measuring the gene expression of silicatein (the enzyme responsible for spicule silicification) and the dimensional changes of spicules during the developmental process of individual sponges and in cell cultures of primmorphs of archaeocyte-dominant cell populations. The different developmental stages of spicules were documented by time-lapse microscopy and observed by transmission electron microscopy during a 1-month culture period. During its annual life cycle, H. perlevis has four different developmental stages: dormancy, resuscitation, bloom, and decline. Field-grown individual sponge samples at different stages were collected over 7 months (March to September 2005). The dimensions of the silica spicules from these samples were microscopically measured and statistically analyzed. This analysis and the material properties of the spicules allowed them to be classified into four groups representing the different developmental stages of spiculogenesis. Silicatein expression in the bloom stage was more than 100 times higher than that in the other stages and was correlated with the spicule developmental stage. The trend of spicule formation in field-grown sponges was consistent with the trend in cell culture. A new parameter, the maturation degree (MD) of spicules (defined as the ratio of actual to theoretical silica deposition of mature spicules), was introduced to quantify spicule development. Silica spiculogenesis during H. perlevis development was delineated by comparing MD and silicatein expression.

Comparison of spiculogenesis in in vitro ADCP-primmorph and explants culture of marine sponge Hymeniacidon perleve with 3-TMOSPU supplementation

This study aims to test the feasibility of introducing functional chemical groups into biogenic silica spicules by examining the effect of supplementing a silican coupler [3-(trimethoxysilyl)propyl]urea (3-TMOSPU) as silica source in the cultures of archaeocytes-dominant-cell-population (ADCP) primmorphs and explants of the marine sponge Hymeniacidon perleve. Analysis by Fourier Transform Infrared Spectroscopy (FT-IR) confirmed that the organic group in 3-TMOSPU was introduced into silica spicules. By comparing ADCP-primmorph cultures when supplemented with Na2SiO3, 3-TMOSPU supplementation showed no notable effect on the primmorphs development and cell locomotion behaviors. A decline in silicatein expression quantified by real-time RT-PCR was, however, observed during spiculogenesis. The decline was slower for the 3-TMOSPU group whereas significantly fewer spicules were formed. When sponge papillae explants were cultured, 3-TMOSPU supplementation had no negative effect on sponge growth but inhibited the growth biofouling of the diatom Nitzschia closterium. By monitoring the detectable Si concentration, it seemed that 3-TMOSPU was converted by the sponge and its conversion was related to spiculogenesis. Analysis of spicule dimensional changes indicated that the inhibition of spiculogenesis by 3-TMOSPU supplementation was less in ADCP-primmorphs culture due to lower 3-TMOSPU/detectable Si ratio in the media.

Purification and in vitro cultivation of archaeocytes (stem cells) of the marine sponge Hymeniacidon perleve (Demospongiae)

Marine sponges (Porifera) are the best source of marine bioactive metabolites for drug discovery and development, although the sustainable production of most sponge-derived metabolites remains a difficult task. In vitro cultivation of sponge cells in bioreactors has been proposed as a promising technology. However, no continuous cell line has as yet been developed. Archaeocytes are considered to be toti/multipotent stem cells in sponges and, when purified, may allow the development of continuous sponge cell lines. As a prerequisite, we have developed a novel four-step protocol for the purification of archaeocytes from a marine sponge, Hymeniacidon perleve: (1) differential centrifugation to separate large sponge cells including archaeocytes; (2) selective agglomeration in low-Ca(2+)/Mg(2+) artificial seawater in which living archaeocytes form small loose aggregates with some pinacocytes and collencytes; (3) differential adherence to remove anchorage-dependent pinacocytes, collencytes and other mesohyl cells; (4) Ficoll-Vrografin density gradient centrifugation to purify archaeocytes. The final purity of archaeocytes is greater than 80%. The proliferation potential of the archaeocytes has been demonstrated by high levels of BrdU incorporation, PCNA expression and telomerase activity. In 4-day primary cultures, the purified archaeocytes show a 2.5-fold increase in total cell number. This study opens an important avenue towards developing sponge cell cultures for the commercial exploitation of sponge-derived drugs.

Marine invertebrate cell cultures: new millennium trends

This review analyzes activities in the field of marine invertebrate cell culture during the years 1999 to 2004 and compares the outcomes with those of the preceding decade (1988 to 1998). During the last 5 years, 90 reports of primary cell culture studies of marine organisms belonging to only 6 taxa (Porifera, Cnidaria, Crustacea, Mollusca, Echinodermata, and Urochordata) have been published. This figure represents a 2-fold increase in the annual number of publications over the decade 1988 to 1998. Three other trends distinguish the two reviewed periods. First, in recent years studies attempting to improve cell culture methodologies have decreased, while interest in applications of already existing methodologies has increased. This reflects the effects of short-term cultures in attracting new researchers and scientific disciplines to the field. Second, only 17.8% of the recent publications used long-term cultures, compared with 30.0% of the publications in the previous decade. Third, during recent years research in cell cultures has studied fewer model species more extensively (mainly, Botryllus schlosseri, Crassostrea, Mytilus, Penaeus, and Suberites domuncula), signifying a shift from previous investigations that had studied a more diverse range of organisms. From 1988 to 1998 the phylum Mollusca was the most studied taxon (34.4%), but recent years have seen more studies of Porifera and Crustacea (30.0% and 32.2% of publications) than of Mollusca (21.1%). Still, not even a single established cell line from any marine invertebrate has yet been made available. However, the use of new cellular, genomic, and proteomic tools may fundamentally change our strategy for the development of cell cultures from marine invertebrates.

Large-scale production of pharmaceuticals by marine sponges: sea, cell, or synthesis?

Marine sponges are known to produce an overwhelming array of secondary metabolites with pharmaceutical potential. The technical and economical potential of using marine sponges for large-scale production of these compounds was assessed for two cases: the anticancer molecule halichondrin B from a Lissodendoryx sp., and avarol from Dysidea avara for its antipsoriasis activity. An economic and technical analysis was done for three potential production methods: mariculture, ex situ culture (in tanks), and cell culture. We concluded that avarol produced by mariculture or ex situ culture could become a viable alternative to currently used pharmaceuticals for the treatment of psoriasis. Production of halichondrin B from sponge biomass was found to not be a feasible process, mainly due to the extremely low concentration of the compound in the sponge. Technical feasibility was also analyzed for five alternatives: chemical synthesis, wild harvest, primmorph culture, genetic modification and semi-synthesis. It was concluded that the latter two approaches could prove to be valuable methods for the production of pharmaceuticals, based on chemical structures of secondary metabolites present in trace amounts in marine sponges.