11 research outputs found
Neue linguistische Methoden und arbeitstechnische Verfahren in der Erschliessung der ägyptischen Grammatik
15 páginas, 1 tabla, 6 figuras.Does diversity beget diversity? Diversity
includes a diversity of concepts because it is linked to
variability in and of life and can be applied to multiple
levels. The connections between multiple levels of
diversity are poorly understood. Here, we investigated
the relationships between genetic, bacterial, and
chemical diversity of the endangered Atlanto-Mediterranean sponge Spongia lamella. These levels of
diversity are intrinsically related to sponge evolution
and could have strong conservation implications. We
used microsatellite markers, denaturing gel gradient
electrophoresis and quantitative polymerase chain
reaction, and high performance liquid chromatography to quantify genetic, bacterial, and chemical
diversity of nine sponge populations. We then used
correlations to test whether these diversity levels
covaried. We found that sponge populations differed
significantly in genetic, bacterial, and chemical
diversity. We also found a strong geographic pattern
of increasing genetic, bacterial, and chemical dissimilarity with increasing geographic distance between
populations. However, we failed to detect significant
correlations between the three levels of diversity
investigated in our study. Our results suggest that
diversity fails to beget diversity within a single species
and indicates that a diversity of factors regulates a
diversity of diversities, which highlights the complex
nature of the mechanisms behind diversityResearch funded by grants from the Agence Nationale de la
Recherche (ECIMAR), from the Spanish Ministry of Science
and Technology SOLID (CTM2010-17755) and Benthomics
(CTM2010-22218-C02-01) and the BIOCAPITAL project
(MRTN-CT-2004-512301) of the European Union. This is a
contribution of the Consolidated Research Group ‘‘Grupo de
Ecologı´a Bento´nica,’’ SGR2009-655.Peer reviewe
Antimicrobial activity of heterotrophic bacterial communities from the marine sponge Erylus discophorus (Astrophorida, Geodiidae)
10 páginas, 3 tablas.Heterotrophic bacteria associated with two specimens of the marine sponge Erylus discophorus were screened for their
capacity to produce bioactive compounds against a panel of human pathogens (Staphylococcus aureus wild type and
methicillin-resistant S. aureus (MRSA), Bacillus subtilis, Pseudomonas aeruginosa, Acinetobacter baumanii, Candida albicans
and Aspergillus fumigatus), fish pathogen (Aliivibrio fischeri) and environmentally relevant bacteria (Vibrio harveyi). The
sponges were collected in Berlengas Islands, Portugal. Of the 212 isolated heterotrophic bacteria belonging to Alpha- and
Gammaproteobacteria, Actinobacteria and Firmicutes, 31% produced antimicrobial metabolites. Bioactivity was found
against both Gram positive and Gram negative and clinically and environmentally relevant target microorganisms.
Bioactivity was found mainly against B. subtilis and some bioactivity against S. aureus MRSA, V. harveyi and A. fisheri. No
antifungal activity was detected. The three most bioactive genera were Pseudovibrio (47.0%), Vibrio (22.7%) and Bacillus
(7.6%). Other less bioactive genera were Labrenzia, Acinetobacter, Microbulbifer, Pseudomonas, Gordonia, Microbacterium,
Micrococcus and Mycobacterium, Paenibacillus and Staphylococcus. The search of polyketide I synthases (PKS-I) and
nonribosomal peptide synthetases (NRPSs) genes in 59 of the bioactive bacteria suggested the presence of PKS-I in 12
strains, NRPS in 3 strains and both genes in 3 strains. Our results show the potential of the bacterial community associated
with Erylus discophorus sponges as producers of bioactive compounds.This research was supported by the European Regional Development Fund (ERDF) through the COMPETE - Operational Competitiveness Programme
and national funds through FCT – Foundation for Science and Technology, under the projects PEst-C/MAR/LA0015/2013, PEst-OE/QUI/UI0612/2011 and PTDC/
QUI-QUI/098053/2008. Ana Patrícia Graçaa acknowledges an ERAMUS fellowship. Joana Bondoso was financed by FCT - Foundation for Science and Technology
(PhD grant SFRH/BD/35933/2007). Joana R. Xavier’s research is funded by an FCT - Foundation for Science and Technology postdoctoral fellowship (grant
no. SFRH/BPD/62946/2009). In addition, this work was funded by the Fundación MEDINA, a public-private partnership of Merck Sharp and Dohme of España/
Universidad de Granada/Junta de AndalucíaPeer reviewe
Abundance and bioactivity of cultured sponge-associated bacteria from the Mediterranean Sea
In this study, the search for new antibiotics was combined with quantitative ecological studies. The cultured fraction of the associated bacterial communities from ten different Mediterranean sponge species was investigated. To obtain quantitative and qualitative data of sponge-associated bacterial communities and to expand the cultured diversity, different media were used. The largest morphological diversity and highest yield of isolates was obtained by using oligotrophic media, which consisted of natural habitat seawater amended with (1% additional carbon sources. The dominant bacterial morphotypes were determined and bacterial isolates were tested for antimicrobial activity and identified using 16S rDNA sequencing. The sponge-associated most abundant morphotypes were all affiliated to the Alphaproteobacteria and showed antimicrobial activity against at least one of the tested strains. In contrast, the ambient seawater was dominated by Gammaproteobacteria. One single alphaproteobacterium, which was related to Pseudovibrio denitrificans, was shown to dominate the cultured community of at least six of the sponges. This designated MBIC3368-like alphaproteobacterium has been isolated from sponges before and seems to be restricted to associations with members of the phylum Porifera. It displays a weak and unstable antimicrobial activity, which gets easily lost during cultivation. However, this bioactive bacterium was present in the sponges by up to 106 cells per gram wet-weight sponge tissue and dominated the cultured fraction with up to 74%. The association of this alphaproteobacterium with sponges is probably evolutionary young and facultative and possibly involves biologically active secondary metabolites. Besides a demonstrated vertical transfer, additional horizontal transfer between the sponges is assumed. Members of the genus Bacillus displaying antimicrobial activity were found regularly, too. However, actinomycetes, which are known for their production of bioactive substances, were present in very low abundance