Cell culture from sponges: pluripotency and immortality

Biomaterials and Bioactive Natural Products from Marine Invertebrates: From Basic Research to Innovative Applications

Aquatic invertebrates are a major source of biomaterials and bioactive natural products that can find applications as pharmaceutics, nutraceutics, cosmetics, antibiotics, antifouling products and biomaterials. Symbiotic microorganisms are often the real producers of many secondary metabolites initially isolated from marine invertebrates; however, a certain number of them are actually synthesized by the macro-organisms. In this review, we analysed the literature of the years 2010–2019 on natural products (bioactive molecules and biomaterials) from the main phyla of marine invertebrates explored so far, including sponges, cnidarians, molluscs, echinoderms and ascidians, and present relevant examples of natural products of interest to public and private stakeholders. We also describe omics tools that have been more relevant in identifying and understanding mechanisms and processes underlying the biosynthesis of secondary metabolites in marine invertebrates. Since there is increasing attention on finding new solutions for a sustainable large-scale supply of bioactive compounds, we propose that a possible improvement in the biodiscovery pipeline might also come from the study and utilization of aquatic invertebrate stem cells.

Breakthrough in Marine Invertebrate Cell Culture: Sponge Cells Divide Rapidly in Improved Nutrient Medium

Sponges (Phylum Porifera) are among the oldest Metazoa and considered critical to understanding animal evolution and development. They are also the most prolific source of marine-derived chemicals with pharmaceutical relevance. Cell lines are important tools for research in many disciplines, and have been established for many organisms, including freshwater and terrestrial invertebrates. Despite many efforts over multiple decades, there are still no cell lines for marine invertebrates. In this study, we report a breakthrough: we demonstrate that an amino acid-optimized nutrient medium stimulates rapid cell division in 9 sponge species. The fastest dividing cells doubled in less than 1 hour. Cultures of 3 species were subcultured from 3 to 5 times, with an average of 5.99 population doublings after subculturing, and a lifespan from 21 to 35 days. Our results form the basis for developing marine invertebrate cell models to better understand early animal evolution, determine the role of secondary metabolites, and predict the impact of climate change to coral reef community ecology. Furthermore, sponge cell lines can be used to scale-up production of sponge-derived chemicals for clinical trials and develop new drugs to combat cancer and other diseases.

Modelling the early evolution of extracellular matrix from modern Ctenophores and Sponges

Animals (metazoans) include some of the most complex living organisms on Earth, with regard to their multicellularity, numbers of differentiated cell types, and lifecycles. The metazoan extracellular matrix (ECM) is well-known to have major roles in the development of tissues during embryogenesis and in maintaining homoeostasis throughout life, yet insight into the ECM proteins which may have contributed to the transition from unicellular eukaryotes to multicellular animals remains sparse. Recent phylogenetic studies place either ctenophores or poriferans as the closest modern relatives of the earliest emerging metazoans. Here, we review the literature and representative genomic and transcriptomic databases for evidence of ECM and ECM-affiliated components known to be conserved in bilaterians, that are also present in ctenophores and/or poriferans. Whereas an extensive set of related proteins are identifiable in poriferans, there is a strikingly lack of conservation in ctenophores. From this perspective, much remains to be learnt about the composition of ctenophore mesoglea. The principal ECM-related proteins conserved between ctenophores, poriferans, and bilaterians include collagen IV, laminin-like proteins, thrombospondin superfamily members, integrins, membrane-associated proteoglycans, and tissue transglutaminase. These are candidates for a putative ancestral ECM that may have contributed to the emergence of the metazoans.

Genetic algorithm as an optimization tool for the development of sponge cell culture media

Sponges are rich sources of novel natural products. Production in cell cultures may be an option for supply of these compounds but there are currently no sponge cell lines. Because there is a lack of understanding about the precise conditions and nutritional requirements that are necessary to sustain sponge cells in vitro, there has yet to be a defined, sponge-specific nutrient medium. This study utilized a genetic algorithm approach to optimize the amino acid composition of a commercially available basal cell culture medium in order to increase the metabolic activity of cells of the marine sponge Dysidea etheria. Four generations of the algorithm were carried out in vitro in wet lab conditions and an optimal medium combination was selected for further evaluation. When compared to the basal medium control, there was a twofold increase in metabolic activity. The genetic algorithm approach can be used to optimize other components of culture media to efficiently optimize chosen parameters without the need for detailed knowledge on all possible interactions.

Cytotoxic Compounds Derived from Marine Sponges. A Review (2010-2012)

Abstract: This extensive review covers research published between 2010 and 2012 regarding new compounds derived from marine sponges, including 62 species from 60 genera belonging to 33 families and 13 orders of the Demospongia class (Porifera). The emphasis is on the cytotoxic activity that bioactive metabolites from sponges may have on cancer cell lines. At least 197 novel chemical structures from 337 compounds isolated have been found to support this work. Details on the source and taxonomy of the sponges, their geographical occurrence, and a range of chemical structures are presented. The compounds discovered from the reviewed marine sponges fall into mainly four chemical classes: terpenoids (41.9%), alkaloids (26.2%), macrolides (8.9%) and peptides (6.3%) which, along with polyketides, sterols, and others show a range of biological activities. The key sponge orders studied in the reviewed research were Dictyoceratida, Haplosclerida, Tetractinellida, Poecilosclerida, and Agelasida. Petrosia, Haliclona (Haplosclerida), Rhabdastrella (Tetractinellida), Coscinoderma and Hyppospongia (Dictyioceratida), were found to be the most promising genera because of their capacity for producing new bioactive compounds. Several of the new compounds and their synthetic analogues have shown in vitro cytotoxic and pro-apoptotic activities against various tumor/cancer cell lines, and some of them will undergo further in vivo evaluation.

Deoxyschizandrin suppresses dss-induced ulcerative colitis in mice

BACKGROUND/AIMS

Deoxyschizandrin as one of the most important component of Schisandra chinensis (Turcz.) Baill plays an immunomodulatory role in a variety of diseases, yet its role in ulcerative colitis remains to be elucidated. We aimed to investigate the role of deoxyschizandrin in DSS-induced ulcerative colitis in mice.

PATIENTS AND METHODS

In the present study, an inflammation model of cells was constructed to confirm the anti-inflammatory effect of deoxyschizandrin. Then a mouse model with Dextran sulfate sodium sulfate (DSS)-induced ulcerative colitis was constructed, and the effects of deoxyschizandrin on mouse colon inflammation, apoptosis, and CD4 T lymphocyte infiltration in ulcerative colitis were examined.

RESULT

Deoxyschizandrin could improve the symptoms of ulcerative colitis, determined by hematoxylin-eosin (HE) staining and histopathological scores. Moreover, deoxyschizandrin reduced the levels of inflammatory cytokines, suppressed CD4 T cell infiltration, and effectively inhibited apoptosis in the colon of DSS-induced ulcerative colitis mice.

CONCLUSION

In summary, deoxyschizandrin can effectively rescue the symptoms of DSS-induced ulcerative colitis in mice by inhibiting inflammation. T cell infiltration and apoptosis in the colon, suggesting that deoxyschizandrin could be a potential drug in treating ulcerative colitis.

In vitro cultures of ectodermal monolayers from the model sea anemone Nematostella vectensis

We report here a novel approach for the extraction, isolation and culturing of intact ectodermal tissue layers from a model marine invertebrate, the sea anemone Nematostella vectensis. A methodology is described in which a brief exposure of the animal to the mucolytic agent N-acetyl-L-cysteine (NAC) solution triggers the dislodging of the ectodermis from its underlying basement membrane and mesoglea. These extracted fragments of cell sheets adherent to culture-dish substrates, initially form 2D monolayers that are transformed within 24 h post-isolation into 3D structures. These ectodermal tissues were sustained in vitro for several months, retaining their 3D structure while continuously releasing cells into the surrounding media. Cultures were then used for cell type characterizations and, additionally, the underlying organization of actin filaments in the 3D structures are demonstrated. Incorporation of BrdU and immunohistochemical labeling using p-histone H3 primary antibody were performed to compare mitotic activities of ectodermal cells originating from intact and from in vivo regenerating animals. Results revealed no change in mitotic activities at 2 h after bisection and a 1.67-, 1.71- and 3.74-fold increase over 24, 48 and 72 h of regeneration, respectively, depicting a significant correlation coefficient (p < 0.05; R ² = 0.74). A significant difference was found only between the control and 3-day regenerations (p = 0.016). Cell proliferation was demonstrated in the 3D ectodermis after 6 culturing days. Moreover, monolayers that were subjected to Ca++/Mg++ free medium for the first 2 h after isolation and then replaced by standard medium, showed, at 6 days of culturing, profuse appearance of positive p-histone H3-labeled nuclei in the 3D tissues. Cytochalasin administered throughout the culturing period abolished all p-histone H3 labeling. This study thus depicts novel in vitro tissue culturing of ectodermal layers from a model marine invertebrate, demonstrating the ease with which experiments can be performed and cellular and molecular pathways can be revealed, thus opening studies on 2D tissue organizations and morphogenesis as well as the roles of cellular components in the formation of tissues in this organism.

Marine Invertebrate Metabolites with Anticancer Activities: Solutions to the "Supply Problem"

Marine invertebrates provide a rich source of metabolites with anticancer activities and several marine-derived agents have been approved for the treatment of cancer. However, the limited supply of promising anticancer metabolites from their natural sources is a major hurdle to their preclinical and clinical development. Thus, the lack of a sustainable large-scale supply has been an important challenge facing chemists and biologists involved in marine-based drug discovery. In the current review we describe the main strategies aimed to overcome the supply problem. These include: marine invertebrate aquaculture, invertebrate and symbiont cell culture, culture-independent strategies, total chemical synthesis, semi-synthesis, and a number of hybrid strategies. We provide examples illustrating the application of these strategies for the supply of marine invertebrate-derived anticancer agents. Finally, we encourage the scientific community to develop scalable methods to obtain selected metabolites, which in the authors' opinion should be pursued due to their most promising anticancer activities.

New marine natural products from sponges (Porifera) of the order Dictyoceratida (2001 to 2012); a promising source for drug discovery, exploration and future prospects

The discovery of new drugs can no longer rely primarily on terrestrial resources, as they have been heavily exploited for over a century. During the last few decades marine sources, particularly sponges, have proven to be a most promising source of new natural products for drug discovery. This review considers the order Dictyoceratida in the Phylum Porifera from which the largest number of new marine natural products have been reported over the period 2001-2012. This paper examines all the sponges from the order Dictyoceratida that were reported as new compounds during the time period in a comprehensive manner. The distinctive physical characteristics and the geographical distribution of the different families are presented. The wide structural diversity of the compounds produced and the variety of biological activities they exhibited is highlighted. As a representative of sponges, insights into this order and avenues for future effective natural product discovery are presented. The research institutions associated with the various studies are also highlighted with the aim of facilitating collaborative relationships, as well as to acknowledge the major international contributors to the discovery of novel sponge metabolites. The order Dictyoceratida is a valuable source of novel chemical structures which will continue to contribute to a new era of drug discovery.

Microbial communities and bioactive compounds in marine sponges of the family irciniidae-a review

Marine sponges harbour complex microbial communities of ecological and biotechnological importance. Here, we propose the application of the widespread sponge family Irciniidae as an appropriate model in microbiology and biochemistry research. Half a gram of one Irciniidae specimen hosts hundreds of bacterial species—the vast majority of which are difficult to cultivate—and dozens of fungal and archaeal species. The structure of these symbiont assemblages is shaped by the sponge host and is highly stable over space and time. Two types of quorum-sensing molecules have been detected in these animals, hinting at microbe-microbe and host-microbe signalling being important processes governing the dynamics of the Irciniidae holobiont. Irciniids are vulnerable to disease outbreaks, and concerns have emerged about their conservation in a changing climate. They are nevertheless amenable to mariculture and laboratory maintenance, being attractive targets for metabolite harvesting and experimental biology endeavours. Several bioactive terpenoids and polyketides have been retrieved from Irciniidae sponges, but the actual producer (host or symbiont) of these compounds has rarely been clarified. To tackle this, and further pertinent questions concerning the functioning, resilience and physiology of these organisms, truly multi-layered approaches integrating cutting-edge microbiology, biochemistry, genetics and zoology research are needed.

Determining the biomass composition of a sponge holobiont for flux analysis

The first step on the path of flux analysis of a new organism with little available literature is the determination of the biomass composition. Once the content of the macromolecular components (protein, RNA, DNA, carbohydrates, lipids) and their composition is known, this composition can be converted into a biomass equation. The biomass equation is an important part of metabolic flux analysis. This equation provides the information about the precursor and energy needs for growth. In many experiments the determination of the growth rate is the simplest flux to be determined, yet this rate determines the net fluxes of a whole range of anabolic pathways in the system and often is used as the objective function in FBA analysis. The challenge for the scientist is to create a biomass equation that represents the organisms of choice under the conditions studied. This chapter outlines basic protocols that can be applied to the quantification of the macromolecular components, using the marine demosponge Amphimedon queenslandica as a case study. As is true for all other sponges and indeed marine animals, A. queenslandica is a holobiont, comprising an animal host plus symbiotic and other associated microbial cells. We show how this complexity can be overcome by developing a fast, yet robust, method for biomass quantification of sponges using the displacement volume. The analytical protocols we describe herein are widely applicable not only to other organisms sampled from complex environments but also to cell cultures. The second part of the chapter highlights the procedures needed to convert a macromolecular composition into a biomass equation.

Primary cell cultures from sea urchin ovaries: a new experimental tool

In the present work, primary cell cultures from ovaries of the edible sea urchin Paracentrotus lividus were developed in order to provide a simple and versatile experimental tool for researches in echinoderm reproductive biology. Ovary cell phenotypes were identified and characterized by different microscopic techniques. Although cell cultures could be produced from ovaries at all stages of maturation, the cells appeared healthier and viable, displaying a higher survival rate, when ovaries at early stages of gametogenesis were used. In terms of culture medium, ovarian cells were successfully cultured in modified Leibovitz-15 medium, whereas poor results were obtained in minimum essential medium Eagle and medium 199. Different substrates were tested, but ovarian cells completely adhered only on poly-L-lysine. To improve in vitro conditions and stimulate cell proliferation, different serum-supplements were tested. Fetal calf serum and an originally developed pluteus extract were detrimental to cell survival, apparently accelerating processes of cell death. In contrast, cells cultured with sea urchin egg extract appeared larger and healthier, displaying an increased longevity that allowed maintaining them for up to 1 month. Overall, our study provides new experimental bases and procedures for producing successfully long-term primary cell cultures from sea urchin ovaries offering a good potential to study echinoid oogenesis in a controlled system and to investigate different aspects of echinoderm endocrinology and reproductive biology.

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.

Bioactive compounds from marine sponges and their symbiotic microbes: a potential source of nutraceuticals

Sponges are considered as the chemical factory in marine environment because of its immense production of chemically diverse compounds. Other than the chemical diversity, these compounds possess remarkable bioactivities. This great potential has aroused applications of sponge-derived compounds as therapeutics and at present, a number of promising compounds are in clinical and preclinical trials. Recently, nutraceuticals have received considerable interest among the health conscious community because of its multiple therapeutic effects. Natural health-promoting substances gain continuous popularity as nutraceuticals due to its reduced risk of side effects. This overview discusses the potentials of marine sponge-derived bioactivities as natural health-promoting compounds.

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.

Cell cultures from marine invertebrates: new insights for capturing endless stemness

Despite several decades of extensive research efforts, there is yet no single permanent cell line available from marine invertebrates as these cells stop dividing in vitro within 24-72 h after their isolation, starting cellular quiescence. This ubiquitous quiescent state should be modified in a way that at least some of the quiescent cells will become pluripotent, so they will have the ability to divide and become immortal. Following the above need, this essay introduces the rationale that the discipline of marine invertebrates' cell culture should gain from applying of two research routes, relevant to mammalian systems but less explored in the marine arena. The first is the use of adult stem cells (ASC) from marine organisms. Many marine invertebrate taxa maintain large pools of ASC in adulthood. Ample evidence attests that these cells from sponges, cnidarians, flatworms, crustaceans, mollusks, echinoderms, and ascidians play important roles in maintenance, regeneration, and asexual cloning, actively proliferating in vivo, resembling the vertebrates' cancer stem cells features. The second route is to target resting somatic cell constituents, manipulating them in the same way as has recently been performed on mammalian induced pluripotent stem (iPS) cells. While "iPS cells" are the outcome of an experimental manipulation, ASC are natural and rather frequent in a number of marine invertebrates. Above two cell categories reveal that there are more than a few types of seeds (cells) waiting to be sowed in the right soil (in vitro environmental conditions) for acquiring stemness and immortality. This rationale carries the potential to revolutionize the discipline of marine invertebrate cell cultures. When cultured "correctly," ASC and "iPS cells" from marine invertebrates may stay in their primitive stage and proliferate without differentiating into cells lineages, harnessing the stem cell's inherent abilities of self-replication versus differentiated progenies, toward the development of immortal cell lines.

Cell cycle analysis of primary sponge cell cultures

Proliferation of sponge cells is generally measured via cell counts or viability assays. However, more insight into the proliferative state of a sponge cell population can be obtained from the distribution of the cells over the different phases of the cell cycle. Cell cycle distribution of sponge cells was measured via flow cytometry after staining the DNA with propidium iodide. The five sponges studied in this paper all showed a large fraction of cells in G1/G0 compared to G2/M and S, indicating that cells were not actively dividing. In addition, some sponges also showed a large apoptotic fraction, indicating cell death. Additional apoptosis measurements, based on caspase activity, showed that harvesting and dissociation of sponge tissue to initiate a primary cell culture was directly correlated with an increase in apoptotic cells. This indicates that for the development of cell cultures, more attention should be given to harvesting, dissociation, and quality of starting material. Finally, cultivation conditions used were ineffective for proliferation, since after 2 d of cultivating Haliclona oculata cells, most cells shifted towards the apoptotic fraction, indicating that cells were dying. For development of in vitro sponge cell cultures, flow cytometric cell cycle analysis is a useful method to assess the proliferative state of a sponge cell culture and can be used to validate improvements in harvesting and dissociation, to select sponges with good proliferative capacities and to study the influence of culture conditions for stimulating cell growth.

Culture of explants from the sponge Mycale cecilia to obtain bioactive mycalazal-type metabolites

Natural products with promising biomedical properties have been described from sponges, but the problem of supply is usually a limiting factor for their pharmacological evaluation. Mycale cecilia produces an array of metabolites containing a pyrrole-2-carbaldehyde moiety (e.g., mycalazals and mycalenitriles) that have shown activity as growth inhibitors of the human prostate carcinoma cell line LNcaP. This study shows that the culture of M. cecilia is a viable method to supply mycalazals while protecting the wild population. Small implants were bound to ceramic tiles, and after 3 to 4 days, the tissue samples formed a secure attachment. Subsequently, these explants were simultaneously cultured in their natural environment and in small tanks for 60 days. Sponges in the tanks were fed a diet consisting of a mixture of two microalgae (Tetraselmis sp. and Isochrysis sp.) and powdered yeast Saccharomyces cerevisiae. The final survival of the explants differed significantly between the two farming methods: It was higher in the natural environment (95 ± 7.07%; overall mean ± standard error) than in the enclosed system (65 ± 21.21%). Growth was also higher than in the tanks, and after 60 days, it increased to 207% in the sea and 65% in the tanks, which represented a daily increase of 3.5% and 1.5%, respectively. At the end of the trial, both the explants cultured in the sea and in the tanks retained the production of bioactive metabolites. The mean concentration of pyrrole-2-carbaldehyde derivatives in wild and cultured sponges was determined by (1)H-NMR. These results demonstrate that in-sea aquaculture of M. cecilia is a viable method for supplying the amounts of mycalazal-type compounds needed to advance the studies on their bioactivity.

Growth efficiency and carbon balance for the sponge Haliclona oculata

To obtain more knowledge about carbon requirements for growth by sponges, the growth rate, respiration rate, and clearance rate was measured in situ in Haliclona oculata. We found that only 34% of the particulate carbon pumped through the sponge was used for both respiration and growth. The net growth efficiency, being the ratio of carbon incorporated in biomass and the total carbon used by the sponge for respiration and growth, was found to be 0.099 +/- 0.013. Thus, about 10% of the total used carbon was fixed in biomass, and over 90% was used for generating energy for growth, maintenance, reproduction, and pumping. H. oculata had 2.5 micromol C available for every micromole O2 consumed. A value of 0.75 for respiratory quotient (RQ in micromole CO2 micromole O2(-1) ) was used for H. oculata, which is the average value reported in literature for different marine invertebrates. Thus, carbon was available in excess to meet the respiratory demand. Oxygen was found not to be the limiting factor for growth, since only 3.3% of the oxygen pumped through the sponge body was used. Our results indicate that both oxygen and carbon availability are not limiting. The low growth efficiency agrees with the low growth rates found for the species used in this study.

Towards commercial production of sponge medicines

Sponges can provide potential drugs against many major world-wide occurring diseases. Despite the high potential of sponge derived drugs no sustainable production method has been developed. Thus far it is not fully understood why, when, where and how these metabolites are produced in sponges. For the near future sea-based sponge culture seems to be the best production method. However, for controlled production in a defined system it is better to develop in vitro production methods, like in vitro sponge culture or even better sponge cell culture, culture methods for symbionts or the transfer of production routes into another host. We still have insufficient information about the background of metabolite production in sponges. Before production methods are developed we should first focus on factors that can induce metabolite production. This could be done in the natural habitat by studying the relation between stress factors (such as predation) and the production of bioactive metabolites. The location of production within the sponge should be identified in order to choose between sponge cell culture and symbiont culture. Alternatively the biosynthetic pathways could be introduced into hosts that can be cultured. For this the biosynthetic pathway of metabolite production should be unraveled, as well as the genes involved. This review discusses the current state of sponge metabolite production and the steps that need to be taken to develop commercial production techniques. The different possible production techniques are also discussed.

Effects of dissolved oxygen levels on survival and growth in vitro of Haliclona pigmentifera (Demospongiae)

In vitro sponge cultures are considered as legitimate alternatives for utilizing marine sponges (Porifera) to yield bioactive molecules. Optimization of culture methodologies for enhancing sponge survival is in progress for the identification of the factors regulating sponge survival in vitro. Dissolved oxygen (DO) is an essential factor promoting sponge survival. However, the effects of variable DO levels on the in vitro survival responses of sponges are not fully understood. Hence, we have investigated the effects of variable DO levels on the survival of the marine sponge, Haliclona pigmentifera (Demospongiae), with no external nutritional supplementation in closed type incubator chambers. Our results indicate that, under hypoxic conditions (1.5-2.0 ppm DO), H. pigmentifera with intact ectodermal layers and subtle oscula show adherent growth for 42+/-3 days. Sponges with prominent oscula, foreign material, and damaged pinacoderm exhibit poor survival under similar conditions. Complete mortality occurs within 2 days under anoxia (<0.3 ppm DO), and survival for a few days has been observed at >4.0 ppm DO without adhesion. Cellular differences between the outer and inner zones and collagen-like extracellular matrix have been identified in adherent sponges. Based on the hypothesis that hypoxia-inducible factor1-alpha (HIF-1alpha) is a ubiquitous protein promoting hypoxic survival in animals, we have detected, by Western blot, a protein band corresponding to human HIF-1alpha-like protein from sponges exposed to hypoxia and to hypoxia-mimicking agents. We thus report, for the first time, adhesive growth and a protein band corresponding to human HIF-1alpha-like protein in sponges surviving hypoxia in vitro.

Potential of sponges and microalgae for marine biotechnology

Marine organisms can be used to produce several novel products that have applications in new medical technologies, in food and feed ingredients and as biofuels. In this paper two examples are described: the development of marine drugs from sponges and the use of microalgae to produce bulk chemicals and biofuels. Many sponges produce bioactive compounds with important potential applications as medical drugs. Recent developments in metagenomics, in the culturing of associated microorganisms from sponges and in the development of sponge cell-lines have the potential to solve the issue of supply, which is the main limitation for sponge exploitation. For the production of microalgal products at larger scales and the production of biofuels, major technological breakthroughs need to be realized to increase the product yield.