Morphological, bacterial, and secondary metabolite changes of Aplysina aerophoba upon long-term maintenance under artificial conditions.

The aim of this study was to analyze successional changes in the bacterial community over a period of 6 months of cultivation of Aplysina aerophoba sponges under different artificial cultivation conditions by use of denaturing gradient gel electrophoresis (DGGE). The cultivation conditions varied concerning the water temperature (20 +/- 2 degrees C and 25 +/- 2 degrees C) of the aquaria, additional illumination of one aquarium, and feeding of the sponges. Amplicons from DGGE separation of dominant colonizing or variably appearing bacteria were sequenced and aligned for taxonomical identification. In addition, secondary metabolites typically found in A. aerophoba were analyzed to investigate changes in the natural product profile during cultivation. The cultivation of sponges under any given condition did not lead to a depletion of their bacterial community in the course of the experiment. On the contrary, the distinctive set of associated bacteria was maintained in spite of a dramatic loss of biomass and morphological degradation during the cultivation period. Generally, all sequences obtained from the DGGE gels were related to bacteria of five phyla: Actinobacteria, Cyanobacteria, alpha-Proteobacteria, gamma-Proteobacteria, and Chloroflexi. Despite the overall stability of the bacterial community in A. aerophoba, an unambiguous variability was detected for the Cyanobacteria "A. aerophoba clone TK09". This variability was ascribed to the predominant light conditions. The analysis of the metabolic pattern revealed that the concentration of a class of characteristic-brominated compounds typically found in A. aerophoba, like aeroplysinin-1, aerophobin-1, aerophobin-2, and isofistularin-3, increased over the 6 months of cultivation.

Hexa-, hepta- and nonaprenylhydroquinones isolated from marine sponges Sarcotragus muscarum and Ircinia fasciculata inhibit NF-kappaB signalling in H4IIE cells.

OBJECTIVES: Marine organisms have proven to be a rich source of potent pharmacologically active compounds. Three polyprenyl-1,4-hydroquinone derivates (hexaprenyl-1,4-hydroquinone, heptaprenyl-1,4-hydroquinone and nonaprenyl-1,4-hydroquinone) were isolated from the Zoobenthos-inhabiting sponges Sarcotragus muscarum and Ircinia fasciculata from the Eastern Mediterranean Sea (phylum: Porifera; class: Demospongiae). METHODS: Hexa-, hepta- and nonaprenylhydroquinone were identified by (1)H-NMR, H,H-COSY, heteronuclear multiple bond correlation, FAB-MS and UV spectroscopy. The effects of the compounds on cell viability was determined using the MTT assay; anti-oxidative potential was measured using the Trolox equivalent antioxidative capacity assay. Inhibition of nuclear factor-kappaB activity was detected by secreted alkaline phosphatase assay. Activity against an array of protein kinases was determined in 96-well FlashPlates. KEY FINDINGS: All compounds had prominent antioxidative activity, comparable to that of the synthetic vitamin E derivate Trolox. Hexaprenylhydroquinone showed the greatest cytotoxicity in H4IIE hepatoma cells (EC50 2.5 muM). All three compounds inhibited NF-kappaB signalling in this cell line, with heptaprenylhydroquinone being the most active. Screening of 23 kinases involved in signal transduction pathways (cell proliferation, survival, angiogenesis and metastasis) showed that hexaprenylhydroquinone and heptaprenylhydroquinone inhibited the activity of the epidermal growth factor receptor (IC50 1.6 and 1.4 mug/ml, respectively), and heptaprenylhydroquinone also inhibited the activity of other kinases (Src tyrosine kinase, vascular endothelial growth factor receptor 3 and insulin-like growth factor 1 receptor). CONCLUSIONS: The prenylated hydroquinones isolated from the marine sponges S. muscarum and I. fasciculata showed cytotoxic and antioxidative activities and inhibited NF-kappaB signalling in H4IIE hepatoma cells and protein kinases. These findings may result in the generation of new lead substances in cancer therapy.

Depth-related alkaloid variation in Mediterranean Aplysina sponges.

Total amounts and patterns of bromoisoxazoline alkaloids of Aplysina sponges from Croatia (Mediterranean Sea) were analyzed along an underwater slope ranging from 1.8 to 38.5 m. Total amounts of alkaloids varied from sample to sample and showed no correlation with depth. In contrast, striking differences of alkaloid patterns were found between sponges from shallow sites (1.8-11.8 m) and those collected from deeper sites (11.8-38.5 m). Sponges from shallow depths consistently exhibited alkaloid patterns typical for Aplysina aerophoba with aerophobin-2 (2) and isofistularin-3 (3) as main constituents. Sponges from deeper sites (below 11.8 m) resembled Aplysina cavernicola with aerothionin (4) and aplysinamisin-1 (1) as major compounds. The typical A. cavernicola pigment 3,4-dihydroxyquinoline-2-carboxylic acid (6), however, could not be detected in A. aerophoba sponges but was replaced by the A. aerophoba pigment uranidine (5) which appeared to be present in all sponge samples analyzed. During transplantation experiments sponges from sites below 30 m featuring the A. cavernicola chemotype of bromoisoxazoline alkaloids were translocated to shallower habitats (10 m). The alkaloid patterns in transplanted sponges were found to be stable over a period of 12 months and unaffected by this change in depth. In a further experiment, clones of Aplysina sponges from shallow depths of 5-6 m resembling the A. aerophoba chemotype were either kept in situ under natural light conditions or artificially shaded by excluding photosynthetically active radiation (PAR). Neither 4 nor 1 were detected in artificially shaded sponges over an observation period of 12 months. In summary, two chemically distinct types of Aplysina sponges were discovered in this study that proved to be remarkably stable with regard to the bromoisoxazoline patterns and unaffected either by changing the light conditions or depth. It is not clear presently whether the Aplysina sponges collected from depths < 11.8 m represent a new chemotype of A. cavernicola lacking the pigment 6 or whether we have incidentally come across a so far undescribed species of the genus Aplysina.

Evolutionary history of Caenorhabditis elegans inferred from microsatellites: evidence for spatial and temporal genetic differentiation and the occurrence of outbreeding.

Although diverse biological disciplines employ the nematode Caenorhabditis elegans as a highly efficient laboratory model system, little is known about its natural history. We investigated its evolutionary past using 10 polymorphic trinucleotide and tetranucleotide microsatellites, derived from across the whole genome. These microsatellites were analyzed from the 35 previously available natural isolates from different parts of the world and also 23 new strains isolated from northwest Germany. Our results highlight that C. elegans lineages differentiate genetically with respect to geographic distance and, to a lesser extent, differences in the time of strain isolation. The latter indicates some turnover of strain genotypes at specific locations. Our data also demonstrate the coexistence of highly diverse genotypes in the population from northwest Germany, which is best explained by recent migration events. Furthermore, selfing is confirmed as the primary mode of reproduction for this hermaphroditic nematode in nature. Importantly, we also find evidence for the occurrence of occasional outbreeding. Taken together, these results support the previous notion that C. elegans is a colonizer, whereby selfing may permit rapid dispersal within new habitats even in the absence of potential mates, whereas occasional outcrossing may serve to compensate for the disadvantages of inbreeding. Such information about the natural history of C. elegans should be of great value for an in-depth understanding of the complexity of this organism, including its multifaceted developmental, neurological, or molecular genetic pathways.