ABSTRACT
The azooxanthellate corals Tubastraea coccinea and T. tagusensis invaded the Brazilian coast in the 1980s and is still in expansion, favored by lower predation and competition pressure in their new habitats. Interestingly, the native sponge Desmapsamma anchorata has been observed overgrowing these corals. Considering that competitive displacement is expected to play a major role in the successful outcome of an invasion, the present study tested the physical and chemical mechanisms possibly involved in the competition between D. anchorata and the Tubastraea corals through field and aquaria experiments as well as the Raman spectroscopy technique for chemical analysis. Our results showed that the sponge grew in all directions including over Tubastraea colonies and regardless of its presence. There was no evidence of a specific chemical response among sponges or corals. However, we observed the extrusion of mesenteric filaments and tentacles of corals and the projection of sponge tissue during interspecific interaction, which suggests that physical imposition plays a key role for space competition at micro scales. Given the interspersed nature of benthic species distributions and the fast expansion of Tubastraea, it is unlikely that D. anchorata or any other sponges could serve a biological control against these invasive corals at larger scales, but our results showed that at a microscale they can withstand the corals presence and even outgrow them locally.
Subject(s)
Anthozoa , Animals , Brazil , Ecosystem , Introduced SpeciesABSTRACT
Abstract The gorgonian Phyllogorgia dilatata Esper is an octocoral known to be source of biologically active terpenes. In this study, odoriferous compounds present in P. dilatata tissues were investigated, due to their exotic olfactory notes. The search of volatile compounds was performed in a dichloromethane/methanol extract submitted to a silica gel vacuum chromatography and HPLC, yielding the isomers (Z,E) and (E,E)-germacrones, identified by GC/MS, 1 and 2D NMR. The stereochemistry of (E,E)-germacrone, as well as its preferred conformation, was confirmed by NOESY. Sensory analysis of the two isomers revealed a fragrant, citrus, woody and weak marine odor, similar to the odor of the natural gorgonian, and (E,E)-germacrone has a three times more intense aroma than the (Z,E) isomer.
ABSTRACT
The aim of the present study was to characterize 16 pharmaceutical grade chondroitin sulfate (CS) samples, concerning the structure and presence of contaminants, in comparison to USP and analytical grade CS. Agarose gel electrophoresis has shown that only 5 samples were >90% CS, while 11 contained less than 15% CS. FACE (fluorophore-assisted carbohydrate electrophoresis) revealed that maltodextrin was the main contaminant in nine of them, and lactose in two. Raman spectroscopy corroborated these results. Concerning the structure of the CS present in the five CS-rich samples, the ratios 4-sulfated:6-sulfated disaccharides varied from 0.9 to 1.7, and their modal molecular weight was 20-29 kDa. Also, they were all contaminated by small amounts of keratan sulfate (<1%). In conclusion, our findings indicate that the composition of CS preparations not always corresponds to the manufacturers' descriptions, and indicate that further characterization should be required for the registry and license of pharmaceutical grade CS.
