Induction of (2'-5')oligoadenylate synthetase in the marine sponges Suberites domuncula and Geodia cydonium by the bacterial endotoxin lipopolysaccharide

Evolution of the Major Components of Innate Immunity in Animals

Innate immunity is present in all animals. In this review, we explore the main conserved mechanisms of recognition and innate immune responses among animals. In this sense, we discuss the receptors, critical for binding to pathogen-associated molecular patterns (PAMPs) or danger-associated molecular patterns (DAMPs); the downstream signaling proteins; and transcription factors that govern immune responses. We also highlight conserved inflammatory mediators that are induced after the recognition of DAMPs and PAMPs. At last, we discuss the mechanisms that are involved in the regulation and/or generation of reactive oxygen species (ROS), influencing immune responses, like heme-oxygenases (HOs).

Differential Transcriptomic Profiles Following Stimulation with Lipopolysaccharide in Intestinal Organoids from Dogs with Inflammatory Bowel Disease and Intestinal Mast Cell Tumor

Lipopolysaccharide (LPS) is associated with chronic intestinal inflammation and promotes intestinal cancer progression in the gut. While the interplay between LPS and intestinal immune cells has been well-characterized, little is known about LPS and the intestinal epithelium interactions. In this study, we explored the differential effects of LPS on proliferation and the transcriptome in 3D enteroids/colonoids obtained from dogs with naturally occurring gastrointestinal (GI) diseases including inflammatory bowel disease (IBD) and intestinal mast cell tumor. The study objective was to analyze the LPS-induced modulation of signaling pathways involving the intestinal epithelia and contributing to colorectal cancer development in the context of an inflammatory (IBD) or a tumor microenvironment. While LPS incubation resulted in a pro-cancer gene expression pattern and stimulated proliferation of IBD enteroids and colonoids, downregulation of several cancer-associated genes such as Gpatch4, SLC7A1, ATP13A2, and TEX45 was also observed in tumor enteroids. Genes participating in porphyrin metabolism (CP), nucleocytoplasmic transport (EEF1A1), arachidonic acid, and glutathione metabolism (GPX1) exhibited a similar pattern of altered expression between IBD enteroids and IBD colonoids following LPS stimulation. In contrast, genes involved in anion transport, transcription and translation, apoptotic processes, and regulation of adaptive immune responses showed the opposite expression patterns between IBD enteroids and colonoids following LPS treatment. In brief, the crosstalk between LPS/TLR4 signal transduction pathway and several metabolic pathways such as primary bile acid biosynthesis and secretion, peroxisome, renin-angiotensin system, glutathione metabolism, and arachidonic acid pathways may be important in driving chronic intestinal inflammation and intestinal carcinogenesis.

Identification of a novel member of 2H phosphoesterases, 2',5'-oligoadenylate degrading ribonuclease from the oyster Crassostrea gigas

Several genes of IFN-mediated pathways in vertebrates, among them the genes that participate in the 2',5'-oligoadenylate synthetase (OAS)/RNase L pathway, have been identified in C. gigas. In the present study, we identified genes, which encode proteins having 2',5'-oligoadenylate degrading activity in C. gigas. These proteins belong to the 2H phosphoesterase superfamily and have sequence similarity to the mammalian A kinase anchoring protein 7 (AKAP7) central domain, which is responsible for the 2',5'-phosphodiesterase (2',5'-PDE) activity. Comparison of the genomic structures of C. gigas proteins with that of AKAP7 suggests that these enzymes originate from a direct common ancestor. However, the identified nucleases are not typical 2',5'-PDEs. The found enzymes catalyse the degradation of 2',5'-linked oligoadenylates in a metal-ion-independent way, yielding products with 2',3' -cyclic phosphate and 5'-OH termini similarly to the 3'-5' bond cleavage in RNA, catalyzed by metal-independent ribonucleases. 3',5'-linked oligoadenylates are not substrates for them. The preferred substrates for the C. gigas enzymes are 5'-triphosphorylated 2',5'-oligoadenylates, whose major cleavage reaction results in the removal of the 5'-triphosphorylated 2',3'-cyclic phosphate derivative, leaving behind the respective unphosphorylated 2',5'-oligoadenylate. Such a cleavage reaction results in the direct inactivation of the biologically active 2-5A molecule. The 2',5'-ribonucleases (2',5'-RNases) from C. gigas could be members of the ancient group of ribonucleases, specific to 2'-5' phosphodiester bond, together with the enzyme that was characterized previously from the marine sponge Tethya aurantium. The novel 2',5'-RNases may play a role in the control of cellular 2-5A levels, thereby limiting damage to host cells after viral infection.

Lipopolysaccharides from Commensal and Opportunistic Bacteria: Characterization and Response of the Immune System of the Host Sponge Suberites domuncula

Marine sponges harbor a rich bacterioflora with which they maintain close relationships. However, the way these animals make the distinction between bacteria which are consumed to meet their metabolic needs and opportunistic and commensal bacteria which are hosted is not elucidated. Among the elements participating in this discrimination, bacterial cell wall components such as lipopolysaccharides (LPS) could play a role. In the present study, we investigated the LPS chemical structure of two bacteria associated with the sponge Suberites domuncula: a commensal Endozoicomonas sp. and an opportunistic Pseudoalteromonas sp. Electrophoretic patterns indicated different LPS structures for these bacteria. The immunomodulatory lipid A was isolated after mild acetic acid hydrolysis. The electrospray ionization ion-trap mass spectra revealed monophosphorylated molecules corresponding to tetra- and pentaacylated structures with common structural features between the two strains. Despite peculiar structural characteristics, none of these two LPS influenced the expression of the macrophage-expressed gene S. domuncula unlike the Escherichia coli ones. Further research will have to include a larger number of genes to understand how this animal can distinguish between LPS with resembling structures and discriminate between bacteria associated with it.

Genotoxicity and activation of cellular defenses in transplanted zebra mussels Dreissena polymorpha along the Seine river

The aim of the present study was to confirm the relevance of studying DNA adduct formation in a field study. In that context, freshwater mussels Dreissena polymorpha, collected in a reference station, were transplanted in different sites with a pollution gradient. After one and two months, mussels were collected and DNA adduct formation was analyzed using the (32)P post labelling technique on both gills and digestive glands. In addition, the expression of genes involved in the detoxification system (catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST), HSP70, aryl hydrocarbon receptor (AHR), P glycoprotein (PgP), metallothionein (MT)) was assessed by RT-PCR. DNA adducts were observed at amount comparable to data from literature. Increase of DNA adducts after two months of transplantation could be correlated with strong modulation of gene expression implicated in detoxification processes. Indeed, PgP and HSP70 gene expressions were similarly induced in gills and digestive glands while SOD and CAT expressions were down regulated in both tissues. AHR, GST and MT genes were differently regulated depending upon the tissue studied and the level of contamination in the different sites. We demonstrated that mussels transplanted in the different stations with pollution gradient were able to biotransform PAHs, assessed by DNA adduct formation and the high decrease of detoxification genes. Specific DNA adducts pattern obtained after one and two month mussel transplantations demonstrated the relevance of DNA adduct as biomarker of environmental pollution.

Enzymatically active 2',5'-oligoadenylate synthetases are widely distributed among Metazoa, including protostome lineage

2',5'-Oligoadenylate synthetases (OASs) belong to the nucleotidyl transferase family together with poly(A) polymerases, CCA-adding enzymes and the recently discovered cyclic-GMP-AMP synthase (cGAS). Mammalian OASs have been thoroughly characterized as components of the interferon-induced antiviral system. The OAS activity and the respective genes were also discovered in marine sponges where the interferon system is absent. In this study the recombinant OASs from several multicellular animals and their closest unicellular relative, a choanoflagellate, were expressed in a bacterial expression system and their enzymatic activities were examined. We demonstrated 2-5A synthesizing activities of OASs from the marine sponge Tedania ignis, a representative of the phylogenetically oldest metazoan phylum (Porifera), from an invertebrate of the protostome lineage, the mollusk Mytilus californianus (Mollusca), and from a vertebrate species, a cartilaginous fish Leucoraja erinacea (Chordata). However, the expressed proteins from an amphibian, the salamander Ambystoma mexicanum (Chordata), and from a protozoan, the marine choanoflagellate Monosiga brevicollis (Choanozoa), did not show 2-5A synthesizing activity. Differently from other studied OASs, OAS from the marine sponge T. ignis was able to catalyze the formation of oligomers having both 2',5'- and 3',5'-phosphodiester linkages. Our data suggest that OASs from sponges and evolutionarily higher animals have similar activation mechanisms which still include different affinities and possibly different structural requirements for the activating RNAs. Considering their 2'- and 3'-specificities, sponge OASs could represent a link between evolutionarily earlier nucleotidyl transferases and 2'-specific OASs from higher animals.

MAP kinase cell signaling pathway as biomarker of environmental pollution in the sponge Suberites domuncula

In the present study, we analyzed the effects of two major pollutants of the environment, tributyltin (TBT) and water-accommodated fraction (WAF) of diesel oil, on MAP kinase activation, apoptosis induction and DNA damage, in the marine sponge Suberites domuncula. Our results clearly demonstrated a differential activation of the MAPKs depending on the chemicals tested. TBT induced the activation of p38 and JNK while diesel oil enhanced activation of both ERK and p38. The activation of MAPKs was observed after 1 h exposure and 6 and 24 h of recovery in seawater. In addition, DNA fragmentation, assessed by two techniques, the Fast micromethod(®) and the TUNEL assay, was detected after sponges were treated with both chemicals. Moreover, the study of caspase 3/7 activity showed that apoptosis was induced and triggered with all concentrations of TBT but only at high diesel oil concentrations. After TBT exposure, a correlation was observed between JNK activation, caspase 3 activity and DNA damage while p38 activation followed the two latter parameters at high concentrations of diesel oil, suggesting that sponges enhanced a specific apoptotic pathway depending on the xenobiotic tested. This study demonstrated a high signal response by the sponge Suberites domuncula to the tested chemicals. Cell signaling pathway studies may thus be of use in water quality biomonitoring programs.

Expressed 2-5A synthetase genes and pseudogenes in the marine sponge Geodia barretti

The 2',5'-oligoadenylate synthetases (2-5A synthetases, OAS) form a family of proteins presented in many branches of Metazoa. The phylum Porifera (sponges) contains OAS proteins which are different from those in vertebrates and form a distinct OAS subfamily. In turn, OAS proteins from different genera of Demospongia show rather low similarities in their primary structures. To ascertain divergence of the OAS genes within a particular sponge genus, we identified the OAS genes from the marine sponge Geodia barretti and compared them with those from another member of the genus Geodia, Geodia cydonium. The identity and similarity of the OAS sequences found in G. barretti with those from G. cydonium were considerably higher than identities and similarities compared with those from other sponges, 75% and 85% versus 27-30% and 42-47%, respectively. We also established the presence of a transcriptionally active polymorphic OAS pseudogene in the genome of G. barretti. The transcripts of the OAS pseudogene(s) lack several internal exons encoding necessary motifs for OAS enzymatic activity. The maintenance and further diversification of OAS gene(s) and pseudogene(s) suggest the prevalence of gene duplication events over the loss of gene duplicates in Geodia genomes during the evolution.

Poriferan survivin exhibits a conserved regulatory role in the interconnected pathways of cell cycle and apoptosis

Survivin orchestrates intracellular pathways during cell division and apoptosis. Its central function as mitotic regulator and inhibitor of cell death has major implications for tumor cell proliferation. Analyses in early-branching Metazoa so far propose an exclusive role of survivin as a chromosomal passenger protein, whereas only later during evolution a complementary antiapoptotic function might have arisen, concurrent with increased organismal complexity. To lift the veil on the ancestral function(s) of this key regulator, a survivin-like protein (SURVL) of one of the earliest-branching metazoan taxa was identified and functionally characterized. SURVL of the sponge Suberites domuncula shares considerable similarities with its metazoan homologs, ranging from conserved exon/intron structure to presence of protein-interaction domains. Whereas sponge tissue shows a low steady-state level, SURVL expression was significantly upregulated in rapidly proliferating primmorph cells. In addition, challenge of tissue and primmorphs with heavy metal or lipopeptide stimulated SURVL expression, concurrent with the expression of a newly discovered caspase. Complementary functional analyses in transfected HEK-293 cells revealed that heterologous expression of a SURVL-EFGP fusion not only promotes proliferation but also enhances resistance to cadmium-induced cell death. Taken together, these results suggest both a deep evolutionary conserved dual role of survivin and an equally conserved central position in the interconnected pathways of cell cycle and apoptosis.

Natural occurrence of 2',5'-linked heteronucleotides in marine sponges

2′,5′-oligoadenylate synthetases (OAS) as a component of mammalian interferon-induced antiviral enzymatic system catalyze the oligomerization of cellular ATP into 2′,5′-linked oligoadenylates (2-5A). Though vertebrate OASs have been characterized as 2′-nucleotidyl transferases under in vitro conditions, the natural occurrence of 2′,5′-oligonucleotides other than 2-5A has never been demonstrated. Here we have demonstrated that OASs from the marine sponges Thenea muricata and Chondrilla nucula are able to catalyze in vivo synthesis of 2-5A as well as the synthesis of a series 2′,5′-linked heteronucleotides which accompanied high levels of 2′,5′-diadenylates. In dephosphorylated perchloric acid extracts of the sponges, these heteronucleotides were identified as A2′p5′G, A2′ p5′U, A2′p5′C, G2′p5′A and G2′ p5′U. The natural occurrence of 2′-adenylated NAD⁺ was also detected. In vitro assays demonstrated that besides ATP, GTP was a good substrate for the sponge OAS, especially for OAS from C. nucula. Pyrimidine nucleotides UTP and CTP were also used as substrates for oligomerization, giving 2′,5′-linked homo-oligomers. These data refer to the substrate specificity of sponge OASs that is remarkably different from that of vertebrate OASs. Further studies of OASs from sponges may help to elucidate evolutionary and functional aspects of OASs as proteins of the nucleotidyltransferase family.

Evolution of the 2'-5'-oligoadenylate synthetase family in eukaryotes and bacteria

The 2'-5'-oligoadenylate synthetase (OAS) belongs to a nucleotidyl transferase family that includes poly(A) polymerases and CCA-adding enzymes. In mammals and birds, the OAS functions in the interferon system but it is also present in an active form in sponges, which are devoid of the interferon system. In view of these observations, we have pursued the idea that OAS genes could be present in other metazoans and in unicellular organisms as well. We have identified a number of OAS1 genes in annelids, mollusks, a cnidarian, chordates, and unicellular eukaryotes and also found a family of proteins in bacteria that contains the five OAS-specific motifs. This indicates a specific relationship to OAS. The wide distribution of the OAS genes has made it possible to suggest how the OAS1 gene could have evolved from a common ancestor to choanoflagellates and metazoans. Furthermore, we suggest that the OASL may have evolved from an ancestor of cartilaginous fishes, and that the OAS2 and the OAS3 genes evolved from a mammalian ancestor. OAS proteins function in the interferon system in mammals. This system is only found in jawed vertebrates. We therefore suggest that the original function of OAS may differ from its function in the interferon system, and that this original function of OAS is preserved even in OAS genes that code for proteins, which do not have 2'-5'-oligoadenylate synthetase activity.

Sponge OAS has a distinct genomic structure within the 2-5A synthetase family

2',5'-Oligoadenylate synthetases (2-5A synthetases, OAS) are enzymes that play an important role in the interferon-induced antiviral defense mechanisms in mammals. Sponges, the evolutionarily lowest multicellular animals, also possess OAS; however, their function is presently unclear. Low homology between primary structures of 2-5A synthetases from vertebrates and sponges renders their evolutionary relationship obscure. The genomic structure of vertebrate OASs has been thoroughly examined, making it possible to elucidate molecular evolution and expansion of this gene family. Until now, no OAS gene structure was available from sponges to compare it with the corresponding genes from higher organisms. In the present work, we determined the exon/intron structure of the OAS gene from the marine sponge Geodia cydonium and found it to be completely different from the strictly conserved exon/intron pattern of the OAS genes from vertebrates. This finding was corroborated by the analysis of OAS genes from another sponge, Amphimedon queenslandica, whose genome was recently sequenced. Our data suggest that vertebrate and sponge OAS genes have no direct common intron-containing ancestor and two (sub)types of OAS may be discriminated. This study opens new perspectives for understanding the phylogenesis and evolution of 2-5A synthetases as well as functional aspects of this multigene family.

Morphogenetic activity of silica and bio-silica on the expression of genes controlling biomineralization using SaOS-2 cells

In a previous study (Schröder et al., J Biomed Mater Res B Appl Biomater 75:387-392, 2005) we demonstrated that human SaOS-2 cells, when cultivated on bio-silica matrices, respond with an increased hydroxyapatite deposition. In the present contribution we investigate if silica-based components (Na-silicate, tetraethyl orthosilicate [TEOS], silica-nanoparticles) (1) change the extent of biomineralization in vitro (SaOS-2 cells) and (2) cause an alteration of the expression of the genes amelogenin, ameloblastin, and enamelin, which are characteristic for an early stage of osteogenesis. We demonstrate that the viability of SaOS-2 cells was not affected by the silica-based components. If Na-silicate or TEOS was added together with ss-glycerophosphate, an organic phosphate donor, a significant increase in biomineralization was measured. Finally, expression levels of the amelogenin, ameloblastin, and enamelin genes were determined in SaOS-2 cells during exposure to the silica-based components. After exposure for 2 days, expression levels of amelogenin and enamelin strongly increased in response to the silica-based components, while no significant change was seen for ameloblastin. In contrast, exposure of SaOS-2 cells to ss-glycerophosphate resulted in increased expression of all three genes. We conclude that the levels of the structural molecules of the enamel matrix, amelogenin and enamelin, increase in the presence of silica-based components and substantially contribute to the extent of hydroxyapatite crystallite formation. These results demonstrate that silica-based components augment hydroxyapatite deposition in vitro and suggest that enzymatically synthesized bio-silica (via silicatein) might be a promising route for tooth reconstruction in vivo.

The 2'-5'-oligoadenylate synthetase in the lowest metazoa: isolation, cloning, expression and functional activity in the sponge Lubomirskia baicalensis

Aquatic animals, especially filter feeders such as sponges [phylum Porifera], are exposed to a higher viral load than terrestrial species. Until now, the antiviral defense system in the evolutionary oldest multicellular organisms, sponges, is not understood. One powerful protection of vertebrates against virus infection is mediated by the interferon (IFN)-inducible 2'-5'-oligoadenylate synthetase [(2-5)A synthetase] system. In the present study we cloned from the freshwater sponge Lubomirskia baicalensis a cDNA encoding a 314 aa long ORF with a calculated size of 35748Da, a putative (2-5)A synthetase, and raised antibodies against the recombinant protein. The native enzyme was identified in a crude extract from L. baicalensis by application of a novel separation procedure based on polymer coated ferromagnetic nanoparticles. The particles were derivatized with a synthetic double-stranded RNA [dsRNA], synthetic poly(I:C), a known allosteric activator of the latent (2-5)A synthetase. These particles were used to separate a single 35kDa protein from a crude extract of L. baicalensis, which cross-reacted with antibodies raised against the sponge enzyme. In situ hybridization studies revealed that highest expression of the gene is seen in cells surrounding the aquiferous canals. Finally primmorphs, an in vitro cell culture system, from L. baicalensis were exposed to poly(I:C); they responded to this dsRNA with an increased expression of the (2-5)A synthetase gene already after a 1-day incubation period. We conclude that sponges contain the (2-5)A synthetase antiviral protection system.

Superparamagnetic gamma-Fe(2)O(3) nanoparticles with tailored functionality for protein separation

Polymer coated superparamagnetic gamma-Fe(2)O(3) nanoparticles were derivatized with a synthetic double-stranded RNA [poly(IC)], a known allosteric activator of the latent (2-5)A synthetase, to separate a single 35 kDa protein from a crude extract which cross reacted with antibodies raised against the sponge enzyme.

Analysis of the axial filament in spicules of the demosponge Geodia cydonium: Different silicatein composition in microscleres (asters) and megascleres (oxeas and triaenes)

The skeleton of the siliceous sponges (Porifera: Hexactinellida and Demospongiae) is supported by spicules composed of bio-silica. In the axial canals of megascleres, harboring the axial filaments, three isoforms of the enzyme silicatein (-alpha, -beta and -gamma) have been identified until now, using the demosponges Tethya aurantium and Suberites domuncula. Here we describe the composition of the proteinaceous components of the axial filament from small spicules, the microscleres, in the demosponge Geodia cydonium that possesses megascleres and microscleres. The morphology of the different spicule types is described. Also in G. cydonium the synthesis of the spicules starts intracellularly and they are subsequently extruded to the extracellular space. In contrast to the composition of the silicateins in the megascleres (isoforms: -alpha, -beta and -gamma), the axial filaments of the microscleres contain only one form of silicatein, termed silicatein-alpha/beta, with a size of 25kDa. Silicatein-alpha/beta undergoes three phosphorylation steps. The gene encoding silicatein-alpha/beta was identified and found to comprise the same characteristic sites, described previously for silicateins-alpha or -beta. It is hypothesized, that the different composition of the axial filaments, with respect to silicateins, contributes to the morphology of the different types of spicules.

Expression and characterization of recombinant 2′,5′-oligoadenylate synthetase from the marine sponge Geodia cydonium

2',5'-oligoadenylate (2-5A) synthetases are known as components of the interferon-induced cellular defence mechanism in mammals. The existence of 2-5A synthetases in the evolutionarily lowest multicellular animals, the marine sponges, has been demonstrated and the respective candidate genes from Geodia cydonium and Suberites domuncula have been identified. In the present study, the putative 2-5A synthetase cDNA from G. cydonium was expressed in an Escherichia coli expression system to characterize the enzymatic activity of the recombinant polypeptide. Our studies reveal that, unlike the porcine recombinant 2-5A synthetase, the sponge recombinant protein associates strongly with RNA from E. coli, forming a heterogeneous set of complexes. No complete dissociation of the complex occurs during purification of the recombinant protein and the RNA constituent is partially protected from RNase degradation. We demonstrate that the sponge recombinant 2-5A synthetase in complex with E. coli RNA catalyzes the synthesis of 2',5'-phosphodiester-linked 5'-triphosphorylated oligoadenylates from ATP, although with a low specific activity. Poly(I).poly(C), an efficient artificial activator of the mammalian 2-5A synthetases, has only a minimal effect (an approximate two-fold increase) on the sponge recombinant 2-5A synthetase/bacterial RNA complex activity.

Analysis of serine proteases from marine sponges by 2-D zymography

Proteolytic activities isolated from the marine demosponges Geodia cydonium and Suberites domuncula were analyzed by 2-D zymography, a technique that combines IEF and zymography. After purification, a 200 kDa proteolytically active protein band was obtained from G. cydonium when analyzed in gelatin copolymerized 1-D zymograms. The enzymatic activity was quantified using alpha-N-benzoyl-D-arginine p-nitroanilide (BAPNA) as a substrate and corresponded to a serine protease. The protease activity was resistant to urea and SDS. DTT and 2-mercaptoethanol (2-ME) did not significantly change the protease activity, but induced a shift in molecular mass of the proteolytic band to lower M(r) values as detected by zymography. Under mild denaturing conditions, lower M(r) bands (<200 kDa) were identified in 1-D zymograms, suggesting that the protease is composed of subunits which retain the catalytic activity. After 2-D zymography, the protease from G. cydonium revealed a pI of 8.0 and an M(r) shift from 200 to 66 kDa. To contrast these results, a cytosolic sample from S. domuncula was analyzed. The proteolytic activity of this sponge after 2-D zymography corresponded to an M(r) of 40 kDa and a pI of 4.0. The biological function of both sponge proteases is not yet known. This study demonstrates that mild denaturing conditions required for IEF may alter the interpretation of the 2-D zymography, and care must be taken during sample preparation.

Okadaic acid, an apoptogenic toxin for symbiotic/parasitic annelids in the demosponge Suberites domuncula

The role of okadaic acid (OA) in the defense system of the marine demosponge Suberites domuncula against symbiotic/parasitic annelids was examined. Bacteria within the mesohyl produced okadaic acid at concentrations between 32 ng/g and 58 ng/g of tissue (wet weight). By immunocytochemical methods and by use of antibodies against OA, we showed that the toxin was intracellularly stored in vesicles. Western blotting experiments demonstrated that OA also existed bound to a protein with a molecular weight of 35,000 which was tentatively identified as a galectin (by application of antigalectin antibodies). Annelids that are found in S. domuncula undergo apoptotic cell death. OA is one candidate inducer molecule of this process, since this toxin accumulated in these symbionts/parasites. Furthermore, we identified the cDNA encoding the multifunctional prosurvival molecule BAG-1 in S. domuncula; it undergoes strong expression in the presence of the annelid. Our data suggest that sponges use toxins (here, OA) produced from bacteria to eliminate metazoan symbionts/parasites by apoptosis.

Novel mechanism for the radiation-induced bystander effect: nitric oxide and ethylene determine the response in sponge cells

Until now the bystander effect had only been described in vertebrates. In the present study the existence of this effect has been demonstrated for the phylogenetically oldest metazoan phylum, the Porifera. We used the demosponge Suberites domuncula for the experiments in the two-chamber-system. The lower dish contained irradiated "donor" cells (single cells) and the upper dish the primmorphs ("recipient" primmorphs). The "donor" cells were treated with UV-B light (40 mJ/cm2) and 100 microM hydrogen peroxide (H2O2), factors that exist also in the natural marine aquatic environment of sponges; these factors caused a high level of DNA strand breaks followed by a reduced viability of the cells. If these cells were added to the "recipient" primmorphs these 3D-cell cultures started to undergo apoptosis. This effect could be abolished by the NO-specific scavenger PTIO and ethylene. The conclusion that NO is synthesized by the UV-B/H2O2-treated cells was supported analytically. The cDNA encoding the enzyme dimethylarginine dimethylaminohydrolase (DDAH) was isolated from the "donor" cells. High levels of DDAH transcripts were measured in UV-B/H2O2-treated "donor" cells while after ethylene treatment the steady-state level of expression drops drastically. We conclude that in the absence of ethylene the concentration of the physiological inhibitor for the NO synthase ADMA is low, due to the high level of DDAH. In consequence, high amounts of NO are released from "donor" cells which cause apoptosis in "recipient" primmorphs. In contrast, ethylene reduces the DDAH expression with the consequence of higher levels of ADMA which prevent the formation of larger amounts of NO. This study describes the radiation-induced bystander effect also for the most basal metazoans and demonstrates that this effect is controlled by the two gases NO and ethylene.

Axial (apical-basal) expression of pro-apoptotic and pro-survival genes in the lake baikal demosponge Lubomirskia baicalensis

Like in all other Metazoa, also in sponges (Porifera) proliferation, differentiation, and death of cells are controlled by apoptotic processes, thus allowing the establishment of a Bauplan (body plan). The demosponge Lubomirskia baicalensis from the Lake Baikal is especially suitable to assess the role of the apoptotic molecules, since its grade of construction is highly elaborated into an encrusting base and branches composed of modules lined up along the apical-basal axis. The four cDNAs, ALG-2, BAK, MA-3, and Bcl-2, were isolated from this sponge species. The expression levels of these genes follow characteristic gradients. While the proapoptotic genes are highly expressed at the base of the branches and comparably low at the top, the pro-survival gene follows an opposite gradient. Parallel with the tuned expression of these genes, the activities of the apoptosis-executing enzymes caspase-8 (IETDase activity) and caspase-3 (DEVDase activity) are lowest at the top of the branch and highest at their base. This characteristic expression/activity pattern of the genes/enzymes, which had been determined in a few specimens, collected from an unpolluted, natural site, appears reversed in specimens collected from an anthropogenically polluted site. These findings indicate the involvement of apoptotic proteins in the axis formation (branches) in L. baicalensis.

Molecular control of serial module formation along the apical–basal axis in the sponge Lubomirskia baicalensis: silicateins, mannose-binding lectin and mago nashi

The freshwater sponge Lubomirskia baicalensis (from Lake Baikal) is characterized by a body plan composed of serial modules which are arranged along an apical-basal axis. In shallow water, the sponge occurs only encrusting, while in deeper environment (>3 m), this species forms branches and grows in an arborescent manner. Each module is stabilized by bundles of spined oxeas (amphioxeae spicules). The spicules are surrounded by an organic matrix. cDNAs for structural proteins (silicatein and mannose-binding lectin (MBL)) as well as for one regulatory protein (mago nashi) were isolated from L. baicalensis. Surprisingly the silicatein alpha molecule exists in several, at least four, isoforms (a1 to a4). Expression studies revealed that the steady-state levels of transcripts for the silicateins, the mannose-binding lectin, and mago nashi are highest at the top of the branches, while only very low levels are found in cells at the base. Based on in situ hybridization studies, evidence is presented that the spicule formation (1) starts and is completed inside of the bundles, and (2) occurs together with the mannose-binding lectin from the surfaces of the bundles. The data suggest that the modules are sequentially formed. It is speculated that the expression of the silicateins and the mannose-binding lectin might be (partially) controlled by mago nashi.

Biosilica formation in spicules of the sponge Suberites domuncula: synchronous expression of a gene cluster

The formation of spicules is a complicated morphogenetic process in sponges (phylum Porifera). The primmorph system was used to demonstrate that in the demosponge Suberites domuncula the synthesis of the siliceous spicules starts intracellularly and is dependent on the concentration of silicic acid. To understand spicule formation, a cluster of genes was isolated. In the center of this cluster is the silicatein gene, which codes for the enzyme that synthesizes spicules. This gene is flanked by an ankyrin repeat gene at one side and by a tumor necrosis factor receptor-associated factor and a protein kinase gene at the other side. All genes are strongly expressed in primmorphs and intact animals after exposure to silicic acid, and this expression is restricted to those areas where the spicule formation starts or where spicules are maintained in the animals. Our observations suggest that in S. domuncula a coordinated expression of physically linked genes is essential for the synthesis of the major skeletal elements.

Selenium affects biosilica formation in the demosponge Suberites domuncula

Selenium is a trace element found in freshwater and the marine environment. We show that it plays a major role in spicule formation in the demosponge Suberites domuncula. If added to primmorphs, an in vitro sponge cell culture system, it stimulates the formation of siliceous spicules. Using differential display of transcripts, we demonstrate that, after a 72-h exposure of primmorphs to selenium, two genes are up-regulated; one codes for selenoprotein M and the other for a novel spicule-associated protein. The deduced protein sequence of selenoprotein M (14 kDa) shows characteristic features of metazoan selenoproteins. The spicule-associated protein (26 kDa) comprises six characteristic repeats of 20 amino acids, composed of 10 distinct hydrophobic regions ( approximately 9 amino acids in length). Recombinant proteins were prepared, and antibodies were raised against these two proteins. Both were found to stain the central axial filament, which comprises the silicatein, as well as the surface of the spicules. In the presence of selenium, only the genes for selenoprotein M and spicule-associated protein are up-regulated, whereas the expression of the silicatein gene remains unchanged. Finally we show that, in the presence of selenium, larger silica aggregates are formed. We conclude that selenium has a stimulatory effect on the formation of siliceous spicules in sponges, and it may be involved in the enzymatic synthesis of biosilica components.

Sustainable use of marine resources: cultivation of sponges

Among all metazoan phyla, sponges are known to produce the largest number of bioactive compounds, some of them metabolites with human therapeutic value. Therefore, an increasing interest in basic cell biology research up to biochemical engineering can be observed aiming at the production of sponge metabolites under completely controlled conditions. One major obstacle is the limited availability of larger quantities of defined sponge material--the so-called supply problem. In this chapter, different approaches used so far for producing sponge biomass by in situ aquaculture as well as some significant progress in the maintenance of sponges in aquaria are reviewed. These approaches are mainly based on old methods for producing commercial bath sponges as well as on experience in maintaining sponges in public aquaria and on the usage of artificial substrates for a natural-like colonization structure. In recent years, great efforts have been made to set up in vitro culture systems for the cultivation of sponge cells. One of the major advantages of cell cultures is the possibility to control and manipulate the cultivation conditions depending on the sponge species and the target metabolite. Up to now, monolayer cultures of dissociated sponge cells have been shown in a few cases to produce the desired product. However, to date, no continuously growing sponge cell line has been established. Organotypic culture systems, which maintain or mimic the natural tissue structure, have been developed in recent years and demonstrate a promising way towards the biotechnology of sponges. Successful attempts to produce sponge metabolites using the three-dimensional growing primmorphs are given. The use of sponge fragments, another three-dimensional approach, has reappeared and has also been successfully used as an in vitro approach as well as for the biotechnological production of boreal sponge tissue.

Innate immune defense of the sponge Suberites domuncula against bacteria involves a MyD88-dependent signaling pathway. Induction of a perforin-like molecule

Sponges (phylum Porifera) are the phylogenetically oldest metazoa; as filter feeders, they are abundantly exposed to marine microorganisms. Here we present data indicating that the demosponge Suberites domuncula is provided with a recognition system for gram-negative bacteria. The lipopolysaccharide (LPS)-interacting protein was identified as a receptor on the sponge cell surface, which recognizes the bacterial endotoxin LPS. The cDNA was isolated, and the protein (Mr 49,937) was expressed. During binding to LPS, the protein dimerizes and interacts with MyD88, which was also identified and cloned. The sponge MyD88 (Mr 28,441) is composed of two protein interaction domains, a Toll/interleukin-1 receptor domain (found in MyD88 and in Toll-like receptors) and a death domain (present in MyD88 and interleukin-1 receptor-associated kinase). Northern blot experiments and in situ hybridization studies showed that after LPS treatment, the level of the LPS-interacting protein remains unchanged, whereas MyD88 is strongly up-regulated. A perforin-like molecule (Mr 74,171), the macrophage-expressed protein, was identified as an executing molecule of this pathway. This gene is highly expressed after LPS treatment, especially at the surfaces of the animals. The recombinant protein possesses biological activity and eliminates gram-negative bacteria; it is inactive against gram-positive bacteria. These data indicate that S. domuncula is provided with an innate immune system against gram-negative bacteria; the ligand LPS (a pathogen-associated molecular pattern) is recognized by the pattern recognition receptor (LPS-interacting protein), which interacts with MyD88. A signal transduction is established, which results in an elevated expression of MyD88 as well as of the macrophage-expressed protein as an executing protein.

Arginine kinase in the demosponge Suberites domuncula:regulation of its expression and catalytic activity by silicic acid

In Demospongiae (phylum Porifera) the formation of the siliceous skeleton,composed of spicules, is an energetically expensive reaction. The present study demonstrates that primmorphs from the demosponge Suberites domuncula express the gene for arginine kinase after exposure to exogenous silicic acid. The deduced sponge arginine kinase sequence displays the two characteristic domains of the ATP:guanido phosphotransferases; it can be grouped to the `usual' mono-domain 40 kDa guanidino kinases (arginine kinases). Phylogenetic studies indicate that the metazoan guanidino kinases evolved from this ancestral sponge enzyme; among them are also the `unusual'two-domain 80 kDa guanidino kinases. The high expression level of the arginine kinase gene was already measurable 1 day after addition of silicic acid by northern blot, as well as by in situ hybridization analysis. Parallel determinations of enzyme activity confirmed that high levels of arginine kinase are present in primmorphs that had been exposed for 1-5 days to silicic acid. Finally, transmission electron-microscopical studies showed that primmorphs containing high levels of arginine kinase also produce siliceous spicules. These data highlight that silicic acid is an inorganic morphogenetic factor that induces the expression of the arginine kinase, which in turn probably catalyzes the reversible transfer of high-energy phosphoryl groups.

Dynamics of skeleton formation in the Lake Baikal sponge Lubomirskia baicalensis. Part II. Molecular biological studies

In a preceding study it has been reported that the freshwater sponge Lubomirskia baicalensis, living in Lake Baikal (East Siberia), is composed of spicules forming a characteristic pattern which follows radiate accretive growth. Here we report that the spicules are synthesized by the enzyme silicatein, a protein which is related to cathepsin L. The cDNAs for silicatein and the related cathepsin L were isolated and used as probes to show that the mRNA levels of silicatein in the bases of the spicule skeleton of the animals are low, while the mRNA level of cathepsin L in this region exceeds that of the growing zone. This is the first comprehensive study on the importance of the axial filament/silicatein as an essential structural and functional component determining the growth and stability of demosponge spicules.

Induction of antiviral immunity by double-stranded RNA in a marine invertebrate

Vertebrates mount a strong innate immune response against viruses, largely by activating the interferon system. Double-stranded RNA (dsRNA), a common intermediate formed during the life cycle of many viruses, is a potent trigger of this response. In contrast, no general inducible antiviral defense mechanism has been reported in any invertebrate. Here we show that dsRNA induces antiviral protection in the marine crustacean Litopenaeus vannamei. When treated with dsRNA, shrimp showed increased resistance to infection by two unrelated viruses, white spot syndrome virus and Taura syndrome virus. Induction of this antiviral state is independent of the sequence of the dsRNA used and therefore distinct from the sequence-specific dsRNA-mediated genetic interference phenomenon. This demonstrates for the first time that an invertebrate immune system, like its vertebrate counterparts, can recognize dsRNA as a virus-associated molecular pattern, resulting in the activation of an innate antiviral response.

A (13)-beta-d-glucan recognition protein from the sponge Suberites domuncula. Mediated activation of fibrinogen-like protein and epidermal growth factor gene expression

Sponges (phylum Porifera) live in a symbiotic relationship with microorganisms, primarily bacteria. Until now, molecular proof for the capacity of sponges to recognize fungi in the surrounding aqueous milieu has not been available. Here we demonstrate, for the demosponge Suberites domuncula (Porifera, Demospongiae, Hadromerida), a cell surface receptor that recognizes (1-->3)-beta-D-glucans, e.g. curdlan or laminarin. This receptor, the (1-->3)-beta-D-glucan-binding protein, was identified and its cDNA analysed. The gene coding for the 45 kDa protein was found to be upregulated in tissue after incubation with carbohydrate. Simultaneously with the increased expression of this gene, two further genes showed an elevated steady state level of expression; one codes for a fibrinogen-like protein and the other for the epidermal growth factor precursor. Expression of the (1-->3)-beta-D-glucan-binding protein and the fibrinogen-like protein occurred in cells on the sponge surface, in the pinacoderm. By Western blotting, the product of the fibrinogen-like protein gene was identified, the recombinant protein isolated, and antibodies raised to this protein. Their application revealed that a 5 kDa factor is produced, which is apparently processed from the 77 kDa epidermal growth factor precursor. Finally, we provided evidence that a tyrosine kinase pathway is initiated in response to exposure to D-glucan; its phosphorylation activity could be blocked by aeroplysinin. In turn, the increased expression of the downstream genes was suppressed. We conclude that sponges possess a molecular mechanism for recognizing fungi via the d-glucan carbohydrates on their surfaces.

Bruton tyrosine kinase-like protein, BtkSD, is present in the marine sponge Suberites domuncula

Sponges, the simplest and most ancient phylum of Metazoa, encode in their genome complex and highly sophisticated proteins that evolved together with multicellularity and are found only in metazoan animals. We report here the finding of a Bruton tyrosine kinase (BTK)-like protein in the marine sponge Suberites domuncula (Demospongiae). The nucleotide sequence of one sponge cDNA predicts a 700-aa-long protein, which contains all of the characteristic domains for the Tec family of protein tyrosine kinases (PTKs). The highest homology (38% identity, 55% overall similarity) was found with human BTK and TEC PTKs. Sponge PTK was therefore named BtkSD. Human BTK is involved in the maturation of B cells and mutations in the BTK gene cause X-linked agammaglobulinemia. Kinases from the Tec family are not present in Caenorhabditis elegans and, until now, they were found only in insects and higher animal taxa. Our finding implies that the BTK/TEC genes are of a very ancient origin.

Traditional and Modern Biomedical Prospecting: Part I-the History: Sustainable Exploitation of Biodiversity (Sponges and Invertebrates) in the Adriatic Sea in Rovinj (Croatia)

Nature, especially the marine environment, provides the most effective drugs used in human therapy. Among the metazoans, the marine sponges (phylum Porifera), which are sessile filter feeders, produce the most potent and highly selective bioactive secondary metabolites. These animals (or their associated symbiotic microorganisms) synthesize secondary metabolites whose activity and selectivity has developed during their long evolutionary history (evochemistry). The exploitation of these resources has become possible due to the progress in molecular and cell biology. BIOTECmarin, the German Center of Excellence follows this rationale. In the past, these animals have been successfully and extensively utilized to isolate bioactive compounds and biomaterials for human benefit. Pharmaceuticals prepared from marine animals, primarily sponges, have been applied since ancient times (Hippocrates, Aristotle and later Plinius). It has been reported that extracts and/or components from sponges can be used for the treatment of specific diseases. For a systematic and applied-oriented exploitation, the successful development of effective compounds largely depends on quality of the institutional infrastructure of marine stations and more so on the biodiversity. The Center for Marine Research in Rovinj (Croatia) fulfils these prerequisites. Founded in 1891, this institute has to its credit major discoveries related to exploitation of secondary metabolites/biomaterials from sponges for therapeutical application and to obtain biomaterials for general wellbeing.

This is the first part of a review focusing on biomedical prospecting. Here, we have mainly described the historic background. The details of techniques, substances, approaches and outlooks will be discussed in the second part.

Emergence and disappearance of an immune molecule, an antimicrobial lectin, in basal metazoa. A tachylectin-related protein in the sponge Suberites domuncula

Sponges (phylum Porifera) represent the evolutionarily oldest metazoans that comprise already a complex immune system and are related to the crown taxa of the protostomians and the deuterostomians. Here, we demonstrate the existence of a tachylectin-related protein in the demosponge Suberites domuncula, termed Suberites lectin. The MAPK pathway was activated in response to lipopolysaccharide treatment of the three-dimensional cell aggregates, the primmorphs; this process was abolished by the monosaccharide D-GlcNAc. The cDNA encoding the S. domuncula lectin was identified and cloned; it comprises 238 amino acids (26 kDa) in the open reading frame. The deduced protein has one potential transmembrane region, three characteristic Cys residues, and six internal tandem repeats; it shares the highest sequence similarity with lectins from the horseshoe crab Tachypleus trunculus. The steady-state level of expression of the Suberites lectin rises in primmorphs in response to lipopolysaccharide, an effect that was prevented by co-incubation with D-GlcNAc. The natural sponge lectin was purified by affinity chromatography; it has a size of 27 kDa and displays antibacterial activity against the Gram-negative bacteria Escherichia coli and the Gram-positive bacteria Staphylococcus aureus. The putative protein, deduced from the cloned gene, is identical/similar to the purified natural protein, as demonstrated by immunological cross-reactivity with specific antibodies. We conclude that the S. domuncula lectin acts as an antibacterial molecule involved in immune defense against bacterial invaders.

Qualitative and quantitative aspects of 2-5A synthesizing capacity of different marine sponges

2-5A synthetase is an important component of the mammalian antiviral 2-5A system. At present, the existence of 2-5A synthetase in the lowest animals, the marine sponges, has been demonstrated, although this enzyme has not been found in bacteria, yeast or plants. Here, we studied the 2-5A synthesizing capacity and the product profile of a variety of marine sponges belonging to Demospongia subclasses Tetractinomorpha and Ceractinomorpha. The 2-5A synthetase activity varied largely, in the range of four orders of magnitude, depending on the sponge species. Compared with the enzymes of the mammalian 2-5A synthetase family, the most active sponge species exhibited a surprisingly high 2-5A synthetase specific activity. Unlike the mammalian 2-5A synthetases that produce 2-5A oligomers in the presence of a double-stranded RNA activator, the 2-5A synthetase(s) from sponges were active without the addition of dsRNA. The sponge species differed in their product profiles. A novel product pool formed by Chondrosia reniformis was identified as a series of long 2-5A oligomers (up to 17-mers) with the prevalence of heptamers and octamers. The large variability of qualitative and quantitative characteristics of sponge 2-5A synthetases may refer to the occurrence of a variety of 2-5A synthetase isozymes in sponges.

Expression of one sponge Iroquois homeobox gene in primmorphs from Suberites domuncula during canal formation

Sponges (Porifera) represent the evolutionary oldest multicellular animals. They are provided with the basic molecules involved in cell-cell and cell-matrix interactions. We report here the isolation and characterization of a complementary DNA from the sponge Suberites domuncula coding for the sponge homeobox gene, SUBDOIRX-a. The deduced polypeptide with a predicted Mr of 44,375 possesses the highly conserved Iroquois-homeodomain. We applied in situ hybridization to localize Iroquois in the sponge. The expression of this gene is highest in cells adjacent to the canals of the sponge in the medulla region. To study the expression of Iroquois during development, the in vitro primmorph system from S. domuncula was used. During the formation of these three-dimensional aggregates composed of proliferating cells, the expression of Iroquois depends on ferric iron and water current. An increased expression in response to water current is paralleled with the formation of canal-like pores in the primmorphs. It is suggested that Iroquois expression is involved in the formation of the aquiferous system, the canals in sponges and the canal-like structures in primmorphs.

Molecular biodiversity. Case study: Porifera (sponges)

Biological diversity--or biodiversity--is the term given to the variety of life on Earth and the natural patterns it forms. The biodiversity we see today is the fruit of billions of years of evolution, shaped by natural processes and, increasingly, by the influence of humans. It forms the web of life of which we are an integral part and upon which we so fully depend. The research on molecular biodiversity tries to lay the scientific foundation of a rational conservation policy that has its roots in various disciplines including systematics/taxonomy (species richness), present day ecology (diversity of ecological systems), and functional genetics (genetic diversity). The results of ongoing genome analyses (genome projects and expressed sequence tag projects) and the achievements of molecular evolution may allow us not only to quantitate the diversity of the present biota but also to extrapolate to their diversification in the future. A link between biodiversity and genomics/molecular evolution will create a platform which we hope may facilitate a sustainable management of organismic life and ensure its exploitation for human benefit. In the present review we outline possible strategies, using the Porifera (sponges) as a prominent example. On the basis of solid taxonomy and ecological data, the high value of this phylum for human application becomes obvious, especially with regard to the field of chemical ecology and the desire to find novel potential drugs for clinical use. In addition, the benefit of trying to make sense of molecular biodiversity using sponges as an example can be seen in the fact that the study of these animals, which are "living fossils", gives us a good insight into the history of our planet, especially with respect to the evolution of Metazoa.

Sponge (2',5')oligoadenylate synthetase activity in the whole sponge organism and in a primary cell culture

A high (2',5')oligoadenylate (2-5A) synthetase activity was found in the marine sponge Geodia cydonium. Here we demonstrate that the 2-5A synthetase activity is present also in other sponge species although the level of the 2-5A synthetase activity varies in several magnitudes in different sponges. The 2-5A synthesizing activity was maintained in the primary culture produced from a sponge.

Sustainable production of bioactive compounds from sponges: primmorphs as bioreactors

Sponges [phylum Porifera] are a rich source for the isolation of biologically active and pharmacologically valuable compounds with a high potential to become effective drugs for therapeutic use. However, until now, only one compound has been introduced into clinics because of the limited amounts of starting material available for extraction. To overcome this serious problem in line with the rules for a sustainable use of marine resources, the following routes can be pursued; first, chemical synthesis, second, cultivation of sponges in the sea (mariculture), third, growth of sponge specimens in a bioreactor, and fourth, cultivation of sponge cells in vitro in a bioreactor. The main efforts to follow the latter strategy have been undertaken with the marine sponge Suberites domuncula. This species produces compounds that affect neuronal cells, such as quinolinic acid, a well-known neurotoxin, and phospholipids. A sponge cell culture was established after finding that single sponge cells require cell-cell contact in order to retain their telomerase activity, one prerequisite for continuous cell proliferation. The sponge cell culture system, the primmorphs, comprises proliferating cells that have the potency to differentiate. While improving the medium it was found that, besides growth factors, certain ions (e.g. silicate and iron) are essential. In the presence of silicate several genes required for the formation of the extracellular matrix are expressed (silicatein, collagen and myotrophin). Fe3+ is essential for the synthesis of the spicules, and causes an increased expression of the ferritin-, septin- and scavenger receptor genes. Furthermore, high water current is required for growth and canal formation in the primmorphs. The primmorph system has already been successfully used for the production of pharmacologically useful, bioactive compounds, such as avarol or (2'-5')oligoadenylates. Future strategies to improve the sponge cell culture are discussed; these include the elucidation of those genes which control the proliferation phase and the morphogenesis phase, two developmental phases which the cells in primmorphs undergo. In addition, immortalization of sponge cells by transfection with genomic DNA appears to be a promising way, since recent studies underscore the applicability of this technique for sponges.

The Chemokine Networks in Sponges: Potential Roles in Morphogenesis, Immunity and Stem Cell Formation

Porifera (sponges) are now well accepted as the phylum which branched off first from the common ancestor of all metazoans, the Urmetazoa. The transition to the Metazoa became possible because during this phase, cell-cell as well as cell-matrix adhesion molecules evolved which allowed the formation of a colonial stage of animals. The next prerequisite for the evolution to the Urmetazoa was the establishment of an effective immune system which, flanked by apoptosis, allowed the formation of a first level of individuation. In sponges (with the model Suberites domuncula and Geodia cydonium), the main mediators of the immune responses are the chemokines. Since sponges lack a vascular system and consequently blood cells (in the narrow sense), we have used the term chemokines (in a broad sense) to highlight that the complex network of intercellular mediators initiates besides differentiation processes also cell movement. In the present review, the cDNAs encoding the following chemokines were described and the roles of their deduced proteins during self-self and nonself recognition outlined: the allograft inflammatory factor, the glutathione peroxidase, the endothelial-monocyte-activating polypeptide, the pre-B-cell colony-enhancing factor and the myotrophin as well as an enzyme, the (2-5)A synthetase, which is involved in cytokine response in vertebrates. A further step required to reach the evolutionary step of the integrated stage of the Urmetazoa was the acquisition of a stem cell system. In this review, first markers for stem cells (mesenchymal stem cell-like protein) as well as for chemokines involved in the maintenance of stem cells (noggin and glia maturation factor) are described at the molecular level, and a first functional analysis is approached. Taken together, it is outlined that the chemokine network was essential for the establishment of metazoans, which evolved approximately 600 to 800 million years ago.