Silicatein expression in Haliclona indistincta (Phylum Porifera, Order Haplosclerida) at different developmental stages.

Silicatein is the main protein responsible for the formation of spicules, tiny structures that constitute the silica skeleton of marine demosponges (Phylum Porifera). A unique innovation in Porifera that evolved from the cathepsin L family of proteins, it has been reported that two amino acids (S and H) are necessary to form the catalytic triad (SHN) to enable silica condensation. However, a diversity of silicatein sequence variants has since been reported with a variable pattern of presence/absence across sponge groups. Variants containing CHN or C/SQN at the active site appear more common in sponges from the Haplosclerida. Here, we report the expression levels of five silicatein variants through different developmental stages in the haplosclerid Haliclona indistincta. All five silicatein variants were expressed at low levels in the free-swimming larvae, which lack spicules and expression significantly increased at the two developmental phases in which spicules were visible. At these two phases, silicateins of CHN and C/SQN types were much more highly expressed than the SHN type indicating a possible ability of active sites with these alternative amino acids to condense silica and a more complex evolutionary story for spicule formation in marine demosponges than previously understood.

Distinct histomorphology for growth arrest and digitate outgrowth in cultivated Haliclona sp. (Porifera: Demospongiae).

The use of sponges in biotechnological processes is limited by the supply problem, and sponge biomass production is becoming a current topic of research. The distinction between characteristics for growth and growth arrest is also important for environmental monitoring. In this study, we analyze the morphology of the digitate outgrowths from the sponge Haliclona sp. The sponge Haliclona sp. was successfully cultivated for 14 months in a closed system. The morphological characterization of growth arrest was performed after submitting explants to starvation-stress for approximately 2 weeks, to correlate morphology with growth and growth arrest. The digitate outgrowth showed three distinct regions: mature (MR), transition (TR) and immature (IR). Our data suggest a growth developmental program, with collagen fascicles guiding axial growth in IR, followed by progressive development of choanocyte chambers and large aquiferous systems at the more mature proximal region (choanosome). The intercalation of choanocyte chambers and small aquiferous systems inside collagen fascicles previously originated at the IR region can be responsible for thickening expansion and conversion of the collagen fascicles into columnar choanosome in MR. The growth arrest after starvation-stress assay showed morphological changes in the IR corroborating collagen in the extreme tip of the digitate outgrowth as an important role in guiding of axial growth of Haliclona sp. The identification of distinct morphologies for growth and growth arrest suggest a growth developmental program, and these data could be useful for further investigations addressing sponge biomass gain and environmental monitoring.

New records of five sponge species (Porifera) for the Black Sea.

The present study deals with five sponge species [Chalinula renieroides, Haliclona (Halichoclona) fulva, H. (Rhizoniera) rosea, Hymedesmia (Hymedesmia) pansa and Ircinia variabilis] belonging to 3 families (Chalinidae, Hymedesmiidae, and Irciniidae) found at one locality (near the opening of Kizilirmak River) on the Black Sea coast of Turkey. All these species are new records for the Black Sea. Three species (Chalinula renieroides, H. (R.) rosea and H. (H.) pansa] are also new records for the marine fauna of Turkey. All these species were previously reported from Mediterranean Sea and the eastern Atlantic Ocean. The morphological and distributional features of these species are presented.

A new species of Haliclona (Demospongiae: Haplosclerida: Chalinidae) from southeastern Brazil and the first record of Haliclona vansoesti from the Brazilian coast.

In this paper we describe two species of the cosmopolitan sponge genus Haliclona from Rio de Janeiro State, SE Brazil, one of which is new to science and the other a new record to Brazil. Haliclona (Rhizoniera) fugidia sp. nov. is brownish-pink, salmon or cream, thickly encrusting, without oscular tubes and tangential ectosomal reticulation. Choanosomal skeleton is a mostly unispicular ladder-like reticulation of oxeas, very organized near the sponge surface and denser and more disorganized in the interior of the sponge. Haliclona (Halichoclona) vansoesti de Weerdt et al., 1999 was originally described from the Caribbean. It has a very loose connection between ectosome and choanosome, a whitish translucent ectosome combined with a purplish choanosome, a cavernous structure and a friable or crispy consistency. The conspecificity of SE Brazilian and Caribbean populations of H. (Halich.) vansoesti was verified through phylogenetic analysis of small subunit 18S rRNA (18S) and mitochondrial cytochrome oxidase subunit I (COI) gene sequences. A maximum likelihood phylogenetic tree constructed with 18S sequences indicates that specimens of H. (Halich.) vansoesti from Rio de Janeiro were phylogenetically closer to the same species from the Caribbean than to other species of Haliclona. Although not available for H. (Halich.) vansoesti from the Caribbean, COI sequences of our specimens were also quite distinct from those of other Haliclona species. Molecular identification based on DNA sequences is a useful complement to traditional morphology-based taxonomy, especially in highly plastic sponges such as Haliclona spp. and other haplosclerids.

New species of Haliclona (Demospongiae: Haplosclerida: Chalinidae) from Western Australia.

Two new sponge species, Haliclona durdong sp. nov. and Haliclona djeedara sp. nov. from the south west of Western Australia are described. Morphologically distinct from each other, both species are assigned to the genus Haliclona subgenus Haliclona. Haliclona djeedara sp. nov. individuals are ficiform to lobate,  brown to beige in colour and have numerous apical oscules. Haliclona durdong sp. nov. individuals have a massive morphology, green colour, and  large funnel-like oscules. The description of these two new species brings the species of Haliclona (Haliclona) in Australia to 25.

Ultrastructure of the ciliated cells of the free-swimming larva, and sessile stages, of the marine sponge Haliclona indistincta (Demospongiae: Haplosclerida).

We provide a detailed, comparative study of the ciliated cells of the marine haplosclerid sponge Haliclona indistincta, in order to make data available for future phylogenetic comparisons at the ultrastructural level. Our study focuses on the description and analysis of the larval epithelial cells, and choanocytes of the metamorphosed juvenile sponge. The ultrastructure of the two cell types is sufficiently different to prevent our ability to conclusively determine the origin of the choanocytes from the larval ciliated cells. However, ciliated, epithelial cells were observed in a migratory position within the inner cell mass of the larval stages. Some cilia were observed within the cell's cytoplasm, which is indicative of the ciliated epithelial cell undergoing transdifferentiation into a choanocyte; while traces of other ciliated epithelial cells were contained within phagosomes, suggesting they are phagocytosed. We compared our data with other species described in the literature. However, any phylogenetic inference must wait until further detailed comparisons can be made with species whose phylogenetic position has been determined by other means, such as phylogenomics, in order to more closely link genomic, and morphological information.

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.

Modelling the skeletal architecture in a sponge with radiate accretive growth.

A mathematical model of the skeletogenesis and the influence of the physical environment on the morphogenesis of a branching sponge, for example, Haliclona oculata or Lubomirskia baikalensis, is presented. In the model, we assume that the radiate accretive growth process is nutrient limited. With this model we can generate in a simulated accretive growth process branching objects with a similarity to the branching sponges.

Seasonal growth rate of the sponge Haliclona oculata (Demospongiae: Haplosclerida).

The interest in sponges has increased rapidly since the discovery of potential new pharmaceutical compounds produced by many sponges. A good method to produce these compounds by using aquaculture of sponges is not yet available, because there is insufficient knowledge about the nutritional needs of sponges. To gain more insight in the nutritional needs for growth, we studied the growth rate of Haliclona oculata in its natural environment and monitored environmental parameters in parallel. A stereo photogrammetry approach was used for measuring growth rates. Stereo pictures were taken and used to measure volumetric changes monthly during 1 year. Volumetric growth rate of Haliclona oculata showed a seasonal trend with the highest average specific growth rate measured in May: 0.012 +/- 0.004 day(-1). In our study a strong positive correlation (p < 0.01) was found for growth rate with temperature, algal biomass (measured as chlorophyll a), and carbon and nitrogen content in suspended particulate matter. A negative correlation (p < 0.05) was found for growth rate with salinity, ammonium, nitrate, nitrite, and phosphate. No correlation was found with dissolved organic carbon, suggesting that Haliclona oculata is more dependent on particulate organic carbon.