First evidence of the presence of chitin in skeletons of marine sponges. Part II. Glass sponges (Hexactinellida: Porifera)

Sponges (Porifera) are presently gaining increased scientific attention because of their secondary metabolites and specific skeleton structures. In contrast to demosponges, whose skeletons are formed from biopolymer spongin, glass sponges (hexactinellids) possess silica-organic composites as the main natural material for their skeletal fibres. Chitin has a crystalline structure and it constitutes a network of organized fibres. This structure confers rigidity and resistance to organisms that contain it, including monocellular (yeast, amoeba, diatoms) and multicellular (higher fungi, arthropods, nematodes, molluscs) organisms. In contrast to different marine invertebrates whose exoskeletons are built of chitin, this polysaccharide has not been found previously as an endogenous biopolymer within glass sponges (Hexactinellida). We hypothesized that glass sponges, which are considered to be the most basal lineage of multicellular animals, must possess chitin. Here, we present a detailed study of the structural and physico-chemical properties of skeletal fragments of the glass sponge Farrea occa. We show that these fibres have a layered design with specific compositional variations in the chitin/silica composite. We applied an effective approach for the demineralization of glass sponge skeletal formations based on an etching procedure using alkali solutions. The results show unambiguously that alpha-chitin is an essential component of the skeletal structures of Hexactinellida. This is the first report of a silica-chitin's composite biomaterial found in nature. From this perspective, the view that silica-chitin scaffolds may be key templates for skeleton formation also in ancestral unicellular organisms, rather than silica-protein composites, emerges as a viable alternative hypothesis.     

The bivalve boring Cuenulites amygdaloides nov. isp. in siliceous sponges from the Upper Cretaceous of Germany

Lower Campanian siliceous sponges from epicontinental deposits of the Subhercynian Cretaceous Basin in Germany contain amygdaloidal depressions which are distinguished as a new ichnospecies of the ichnogenus Cuenulites. These bioerosion traces are interpreted as borings of semi-endolithic bivalves, produced without significant rotation movement, probably mostly by chemical action. As there are no signs of tissue reaction in the bored sponges, the structure is considered to be produced post mortem to the sponge, probably in a foreshore-shoreface setting, with redeposition offshore.     

Serotonin-producing pancreatic endocrine tumour. Histological, ultrastructural and immunohistochemical study of a case

Serotonin-producing pancreatic endocrine tumours are rare neoplasms which in most cases exhibit malignant biological behaviour. These tumours, in the majority of the well-documented cases, are composed of argyrophil- and argentaffin-positive cells which contain large pleomorphic neurosecretory granules. In contrast, argyrophilic non-argentaffin pancreatic endocrine tumours with tumour cells containing round neurosecretory granules are exceptional. In this study we describe such a tumour not associated with clinical evidence of carcinoid syndrome in a 60-year-old woman. Histological examination revealed tumour extension in pancreatic lymphatic vessels and veins but no evidence of locoregional or distant metastases. Ten months after surgery the patient showed no recurrence of the disease. Immunohistochemistry revealed cytoplasmic serotonin production in the tumour cells which were negative for anti-gastrin, insulin, glucagon, somatostatin, pancreatic polypeptide (PP), vasoactive intestinal peptide (VIP) and ACTH. This study emphasizes the usefulness of combined ultrastructural and immunohistochemical investigations in order to identify and characterize the rare pancreatic endocrine tumours with serotonin production.     

An autopsy case of tuberous sclerosis. Histological and immunohistochemical study.

We report an autopsy case of tuberous sclerosis. A 19-year-old Japanese man had shown facial adenoma sebaceum, intractable convulsive seizures and severe mental retardation. Gross inspection of the brain showed a cortical tuber from the orbital frontal lobe to the rhinencephalon of the left side and a few subependymal nodules. Histological examination revealed many cortical tubers in the cerebral hemispheres, a few subependymal nodules with calcification and multifocal clusters of heterotopic cells in the white matter (white matter nodules). In these lesions, massive giant cells with abundant eosinophilic cytoplasm and without Nissl substances were found. Although the size and shape of the giant cells were variable, the majority of them were gemistcytic, ovoid or polygonal. Immunohistochemistry was employed in these lesions using antibodies against neurofilament protein (NFP), glial fibrillary acidic protein (GFAP), vimentin (VM) and myelin basic protein (MBP). In the cortical tuber, the majority of the giant cells were positive for both NFP and VM, but a few were positive for GFAP. All of them were negative for MBP. In the subependymal nodule and white matter nodule, the majority of the giant cells were positive for NFP, but a few were positive for VM, and none were positive for either GFAP and MBP. These findings suggest that the majority of the giant cells may be immature cells toward neuronal series and a few may be those toward astroglial series. These findings also indicate that the giant cells in the subependymal nodule and white matter nodule may be more differentiated than those in the cortical tuber. The nature of the giant cells in tuberous sclerosis is discussed.     

Ocean acidification and calcifying reef organisms: a mesocosm investigation

A long-term (10 months) controlled experiment was conducted to test the impact of increased partial pressure of carbon dioxide (pCO₂) on common calcifying coral reef organisms. The experiment was conducted in replicate continuous flow coral reef mesocosms flushed with unfiltered sea water from Kaneohe Bay, Oahu, Hawaii. Mesocosms were located in full sunlight and experienced diurnal and seasonal fluctuations in temperature and sea water chemistry characteristic of the adjacent reef flat. Treatment mesocosms were manipulated to simulate an increase in pCO₂ to levels expected in this century [midday pCO₂ levels exceeding control mesocosms by 365 ± 130 μatm (mean ± sd)]. Acidification had a profound impact on the development and growth of crustose coralline algae (CCA) populations. During the experiment, CCA developed 25% cover in the control mesocosms and only 4% in the acidified mesocosms, representing an 86% relative reduction. Free-living associations of CCA known as rhodoliths living in the control mesocosms grew at a rate of 0.6 g buoyant weight year⁻¹ while those in the acidified experimental treatment decreased in weight at a rate of 0.9 g buoyant weight year⁻¹, representing a 250% difference. CCA play an important role in the growth and stabilization of carbonate reefs, so future changes of this magnitude could greatly impact coral reefs throughout the world. Coral calcification decreased between 15% and 20% under acidified conditions. Linear extension decreased by 14% under acidified conditions in one experiment. Larvae of the coral Pocillopora damicornis were able to recruit under the acidified conditions. In addition, there was no significant difference in production of gametes by the coral Montipora capitata after 6 months of exposure to the treatments.     

Optimization of AFLP fingerprinting of organisms with a large-sized genome: a study on Alstroemeria spp.

 The recently introduced PCR-based DNA fingerprinting technique AFLP (amplified fragment length polymorphism) allows the selective amplification of subsets of genomic restriction fragments. AFLP has been used for multiple purposes such as the construction of linkage maps, marker saturation at specific genomic regions, analysis of genetic diversity and molecular phylogeny and cultivar identification. AFLP can be tailored by varying the number of selective nucleotides added to core primers and can allow accurate amplification, even in complex template mixtures generated from plant species with very large genomes. In this study Alstroemeria, a plant species with a very large genome, was tested for adapting the AFLP protocol. The results indicated that the estimated number of amplification products was close to the observed number when eight selective nucleotides were used but that seven selective nucleotides did not increase the number of amplification products fourfold. However, we found reproducibility in both +7 and +8 fingerprints. Various distributions of selective nucleotides over the various rounds of preamplifications were tested. Preamplification with four selective nucleotides followed by final amplification with eight selective nucleotides produced clear and reproducible AFLP patterns. The effects of GC content of primers and multiple preamplification steps were also discussed. Received: 16 March 1998 / Accepted: 14 July 1998     

The effect of benzo[a]pyrene on sponges as model organisms in marine pollution

The majority of the investigations were performed with the marine sponge Tethya lyncurium at concentrations of 2 X 10(-8) to 1 X 10(-11) g/ml of benzo[a]pyrene (BaP). Sea-pollution was characterized as BaP equivalent activity in the Ames test. Increased activity of ornithine decarboxylase (ODC) was observed when sponges were artificially exposed at polluted marine areas for 3 weeks. In contrast to the situation in higher animals no ODC induction of the fast type was observed. Mixed function oxygenases (MFO) were not detected in sponges nor could they be induced as in vertebrates. BaP was absorbed by Tethya and concentrated 30--60-fold. In live, but not dead, artificially perfused sponges [3H]- and [14C]BaP-radiolabeled became firmly associated with DNA, RNA and protein of the sponges. The association persisted in isolated fractions, in nucleotides, in nucleosides and in protein hydrolysates. The BaP binding ratio to DNA was found to be strongly correlated to the concentration of BaP. Light modifies BaP and thus enables binding. In the dark only very low association, if any, is observed. The possible consequences of these findings are discussed.     

Comparative study of the choanosome of porifera: II. The keratose sponges

The aquiferous system of representatives of the orders Dictyocer-atida, Dendroceratida, and Verongida has been studied to note its relevance to the systematics of the groups. The volume of the choanocyte chamber, the size and shape of the choanocytes, the number of choanocytes per chamber, the relative development of the mesohyl, and the features of endopinacocytes are estimated from scanning and transmission electron microscopic observations of representatives of most families of the three orders. Although the Dysideidae have a reticulate skeleton and were classified in the order Dictyoceratida, they are actually closer to the Aplysillidae (Dendroceratida) than to dictyoceratids. The anatomy and cytology of the Halisarcidae differ profoundly from those of these three orders and are clearly more closely related to nonkeratose sponges. Some changes in classification lead to a pattern with highly homogeneous orders that clearly differ in their anatomic and cytologic features, which does not support the hypothesis of a common origin of the “keratose” sponges.     

Synthesis of novel triplet drugs with 1,3,5-trioxazatriquinane skeletons and their pharmacologies. 1: Synthesis of triplet drugs with morphinan skeletons

We synthesized symmetrical and nonsymmetrical triplet drugs with 1,3,5-trioxazatriquinane skeletons. The isolation of key intermediates, oxazoline dimers, made it possible to effectively produce nonsymmetrical triplets. Among the synthesized triplets, KNT-93, composed of three identical opioid μ receptor agonists, showed dose-dependent antinociception via the μ receptor. The effect was 56-fold more potent than that of morphine, a representative μ agonist. The profound analgesic effect induced by KNT-93 might result from simultaneous occupation of three μ opioid receptors.     

The interactions of neuropeptides with membrane model systems: a case study.

The interactions between the positively charged neuropeptides substance P (SP), bradykinin (BK), and zwitterionic Met-enkephalin (ME) neuropeptides, and negatively charged SDS and zwitterionic lysophosphatidylcholine (LPC) membrane model systems, have been investigated using one- and two-dimensional nmr experiments. Proton longitudinal relaxation studies were used to characterize these interactions as intrinsic or extrinsic. An extrinsic interaction are similar to those observed for extrinsic membrane proteins. An intrinsic interaction are similar to those observed for intrinsic membrane proteins, and would require that the hydrophobic residues penetrate or insert into the hydrophobic core of the membrane. The interactions between both SP and BK and SDS, based on nmr results, may be characterized as intrinsic, and the interaction between ME and SDS may be characterized as extrinsic. Two-dimensional nuclear Overhauser enhancement spectroscopy experiments proved the insertion of the phenylalanine residues on both SP and BK into the hydrophobic core of SDS micelles. The interaction between SP and BK with LPC based on nmr results are characterized as extrinsic, with the interaction between ME and SDS characterized as weakly intrinsic.     

Rheumatoid arthritis and food: a case study.

Clinical and laboratory studies in a patient whose rheumatoid arthritis appeared to be exacerbated by dairy produce showed that challenge with milk and cheese resulted in a produced increase in synovitis and changes in immune complexes, IgE antibodies, and heat-damaged red cell clearance rates. Exclusion of dairy products from the diet produced a considerable improvement in her previously aggressive disease.     

Selective solution of macroinvertebrate calcareous hard parts: a laboratory study

Ten suites of 16 common types of invertebrate hard parts were placed in acid baths for 24 hours to determine relative rates and common styles of dissolution. Skeletal mineralogies included aragonite and both high-magnesium and low-magnesium calcite. Hard parts included barnacle cxoskelctons, cchinoid tests, gastropod opercula and gastropod and bivalve shells. Calcitic barnacle plates dissolved most rapidly, aragonitic and high magnesium calcitic hard parts showed intermediate rates, and the calcitic shells of the oyster dissolved at the lowest rate. The surface area to weight ratio of the hard parts correlated ( r =0.650) significantly with the hard part's rate of dissolution. Skeletal remains with a high surface area to weight ratio dissolved faster than those with a low surface area to weight ratio. Skeletal porosity and mineralogy appeared to be responsible for additional variation in the rate of dissolution. The effect of the surface area to weight ratio is sufficient to overcome the effect of mineralogy. Dense, compact aragonitic hard parts can persist longer than porous, thin calcitic remains. Typical features associated with skeletal degradation include development of chalky textures, thinning of distal margins, surface etching and formation of holes in bivalve muscle scars. Such features may aid in the recognition of partial dissolution of skeletal remains in the rock record. □ Taphonomy, paleoecology, fossil-diagenesis.     

First evidences of surfactant biodegradation by marine sponges (Porifera): an experimental study with a linear alkylbenzenesulfonate

The main objective of this work was to better appreciate the role of benthic macro-organisms in the biodegradation of detergents in the marine environment. Sponges, which could be highly resistant to pollution and which are highly active filter-feeders, appear as interesting organisms in this topic. An experimental study conducted in aquarium with seawater enriched in a pure linear alkylbenzenesulfonate (LAS), namely 1-(p-Sulfophenyl)nonane, has shown that the primary degradation was 10 times more rapid in the presence of the sponge Spongia officinalis than in the presence of only marine bacteria. The main degradation metabolites, 3-(p-sulfophenyl)propionic acid and p-sulfobenzoic acid were produced in greater amounts in the presence of sponge. The very rapid degradation kinetics observed in this study may be due to the symbiotic microbial community present in S. officinalis. The sponge may also have promoted the activity of marine bacteria by transforming the original molecule in a more available secondary product. This study demonstrates for the first time that benthic macro-organisms can play an important role in the transformation of biodegradable contaminants, such as LAS.