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Papers by Peter Schupp

Palaeogeogr Palaeoclimatol, 2002

Analysis of the Papua New Guinean sponge Theonella swinhoei afforded a new calyculinamide-related... more Analysis of the Papua New Guinean sponge Theonella swinhoei afforded a new calyculinamide-related congener for which we propose the name swinhoeiamide A (1). The structure of the new compound was unambiguously established on the basis of NMR spectroscopic ( 1 H, 13 C, COSY, HMBC) and mass spectrometric (FABMS) data. Swinhoeiamide A exhibited insecticidal activity toward neonate larvae of the polyphagous pest insect Spodoptera littoralis when incorporated in an artificial diet offered to the larvae in a chronic feeding bioassay (ED 50 2.11 ppm, LD 50 2.98 ppm). Furthermore, it was found to be fungicidal against Candida albicans and Aspergillus fumigatus (MIC 1.2 and 1.0 µg/mL, respectively).

Applied and Environmental Microbiology, 2004

Información del artículo Evidence for Acyl Homoserien Lactone Signal Production in Bacteria Assoc... more Información del artículo Evidence for Acyl Homoserien Lactone Signal Production in Bacteria Associated with Marine Sponges.

Phys Rev D, Mar 17, 2011

Photon-neutrino interactions arise quite naturally in noncommutative field theories. Such couplin... more Photon-neutrino interactions arise quite naturally in noncommutative field theories. Such couplings are absent in ordinary field theory and imply experimental lower bounds on the energy scale ΛNC˜|θ|-2 of noncommutativity. Using nonperturbative methods and a Seiberg-Witten map based covariant approach to noncommutative gauge theory, we obtain θ-exact expressions for the interactions, thereby eliminating previous restrictions to low-energy phenomena. We discuss implications for plasmon decay, neutrino charge radii, big bang nucleosynthesis, and ultrahigh energy cosmic rays. Our results behave reasonably throughout all interaction energy scales, thus facilitating further phenomenological applications.

Journal of natural products, Jan 9, 2015

Phyllodesmium is a tropical marine slug genus with about 30 described species. None of them have ... more Phyllodesmium is a tropical marine slug genus with about 30 described species. None of them have a protective shell, and all of them feed on octocorals that are generally known to provide defensive compounds and thus help to defend the naked slugs against sympatric predators, such as fish, crabs, cephalopods, and echinoderms. Phyllodesmium longicirrum is the species that grows the biggest and that is least protected by camouflage on its respective food, usually a soft coral of the genus Sarcophyton. Investigation of the lipophilic extract of a single specimen of P. longicirrum from the Great Barrier Reef (Australia) led to the isolation of four new polycyclic diterpenes. Compound 1 showed significant deterrent activity in a fish feeding assay.

Journal of Experimental Marine Biology and Ecology, Mar 1, 2011

Sponges have evolved a variety of chemical and structural defense mechanisms to avoid predation. ... more Sponges have evolved a variety of chemical and structural defense mechanisms to avoid predation. While chemical defense is well established in sponges, studies on structural defense are rare and with ambiguous results. We used field and laboratory experiments to investigate predation patterns and the anti-predatory defense mechanisms of the sponge Melophlus sarasinorum, a common inhabitant of Indo-pacific coral reefs. Specifically, we aimed to investigate whether M. sarasinorum is chemically or structurally defended against predation and if the defenses are expressed differently in the ectosomal and choanosomal tissue of the sponge. Chemical defense was measured as feeding deterrence, structural defense as feeding deterrence and toughness. Our results demonstrated that chemical defense is evenly distributed throughout the sponge and works in conjunction with a structurally defended ectosome to further reduce predation levels. The choanosome of the sponge contained higher protein levels, but revealed no structural defense. We conclude that the equal distribution of chemical defenses throughout M. sarasinorum is in accordance with Optimal Defense Theory (ODT) in regards to fish predation, while structural defense supports ODT by being restricted to the surface layer which experiences the highest predation risks from mesograzers.

PLOS ONE, 2015

Sponges and other sessile invertebrates are lacking behavioural escape or defense mechanisms and ... more Sponges and other sessile invertebrates are lacking behavioural escape or defense mechanisms and rely therefore on morphological or chemical defenses. Studies from terrestrial systems and marine algae demonstrated facultative defenses like induction and activation to be common, suggesting that sessile marine organisms also evolved mechanisms to increase the efficiency of their chemical defense. However, inducible defenses in sponges have not been investigated so far and studies on activated defenses are rare. We investigated whether tropical sponge species induce defenses in response to artificial predation and whether wounding triggers defense activation. Additionally, we tested if these mechanisms are also used to boost antimicrobial activity to avoid bacterial infection. Laboratory experiments with eight pacific sponge species showed that 87% of the tested species were chemically defended. Two species, Stylissa massa and Melophlus sarasinorum, induced defenses in response to simulated predation, which is the first demonstration of induced antipredatory defenses in marine sponges. One species, M. sarasinorum, also showed activated defense in response to wounding. Interestingly, 50% of the tested sponge species demonstrated induced antimicrobial defense. Simulated predation increased the antimicrobial defenses in Aplysinella sp., Cacospongia sp., M. sarasinorum, and S. massa. Our results suggest that wounding selects for induced antimicrobial defenses to protect sponges from pathogens that could otherwise invade the sponge tissue via feeding scars.

Journal of Mathematical Physics, 2014

We analyse the symmetries underlying nonassociative deformations of geometry in nongeometric R-fl... more We analyse the symmetries underlying nonassociative deformations of geometry in nongeometric R-flux compactifications which arise via T-duality from closed strings with constant geometric fluxes. Starting from the non-abelian Lie algebra of translations and Bopp shifts in phase space, together with a suitable cochain twist, we construct the quasi-Hopf algebra of symmetries that deforms the algebra of functions and the exterior differential calculus in the phase space description of nonassociative R-space. In this setting nonassociativity is characterised by the associator 3-cocycle which controls non-coassociativity of the quasi-Hopf algebra. We use abelian 2-cocycle twists to construct maps between the dynamical nonassociative star product and a family of associative star products parametrized by constant momentum surfaces in phase space. We define a suitable integration on these nonassociative spaces and find that the usual cyclicity of associative noncommutative deformations is replaced by weaker notions of 2-cyclicity and 3-cyclicity. Using this star product quantization on phase space together with 3-cyclicity, we formulate a consistent version of nonassociative quantum mechanics, in which we calculate the expectation values of area and volume operators, and find coarse-graining of the string background due to the R-flux. *

Physical Review D, 2011

Photon-neutrino interactions arise quite naturally in noncommutative field theories. Such couplin... more Photon-neutrino interactions arise quite naturally in noncommutative field theories. Such couplings are absent in ordinary field theory and imply experimental lower bounds on the energy scale Λ NC ∼ |θ| −2 of noncommutativity. Using non-perturbative methods and a Seiberg-Witten map based covariant approach to noncommutative gauge theory, we obtain θ-exact expressions for the interactions, thereby eliminating previous restrictions to low-energy phenomena. We discuss implications for plasmon decay, neutrino charge radii, big bang nucleosynthesis and ultrahigh energy cosmic rays. Our results behave reasonably throughout all interaction energy scales, thus facilitating further phenomenological applications.

Journal of natural products, 2003

Chemical investigation of the Micronesian ascidian Eudistoma sp. afforded two new eudistomin cong... more Chemical investigation of the Micronesian ascidian Eudistoma sp. afforded two new eudistomin congeners, which were designated eudistomins W (1) and X (2). The structures of the new compounds were unambiguously established on the basis of NMR spectroscopic ((1)H, (13)C, COSY, (1)H detected direct, and long-range (13)C-(1)H correlations) and mass spectrometric (EI and ESIMS) data. Compound 2 exhibited antibiotic activity toward Bacillus subtilis, Staphyloccocus aureus, and Escherichia coli and was also found to be fungicidal against Candida albicans in an agar diffusion assay. Compound 1 was selectively active against C. albicans but showed no antibacterial activity.

Natural product communications, 2009

The cancer chemopreventive and cytotoxic properties of 50 extracts derived from Twilight Zone (50... more The cancer chemopreventive and cytotoxic properties of 50 extracts derived from Twilight Zone (50-150 m) sponges, gorgonians and associated bacteria, together with 15 extracts from shallow water hard corals, as well as 16 fractions derived from the methanol solubles of the Twilight Zone sponge Suberea sp, were assessed in a series of bioassays. These assays included: Induction of quinone reductase (QR), inhibition of TNF-alpha activated nuclear factor kappa B (NFkappaB), inhibition of aromatase, interaction with retinoid X receptor (RXR), inhibition of nitric oxide (NO) synthase, inhibition 2,2-diphenyl-1-picrylhydrazyl radical scavenging (DPPH), and inhibition of HL-60 and MCF-7 cell proliferation. The results of these assays showed that at least 10 extracts and five fractions inhibited NFkappaB by greater than 60%, two extracts and two fractions inhibited DPPH by more than 50%, nine extracts and two fractions affected the survival of HL-60 cells, no extracts or fractions affected ...

Marine biotechnology (New York, N.Y.), 2014

Marine sponges contain dense and diverse microbial communities, which are renowned as a source of... more Marine sponges contain dense and diverse microbial communities, which are renowned as a source of bioactive metabolites. The biological activities of sponge-microbe natural products span a broad spectrum, from antibacterial and antifungal to antitumor and antiviral applications. However, the potential of sponge-derived compounds has not been fully realized, due largely to the acknowledged "supply issue." Most bacteria from environmental samples have resisted cultivation on artificial growth media, and cultivation of sponge-associated bacteria has been a major focus in the search for novel marine natural products. One approach to isolate so-called "uncultivable" microorganisms from different environments is the diffusion growth chamber method. Here, we describe the first application of diffusion growth chambers for the isolation of cultivable and previously uncultivated bacteria from sponges. The study was conducted by implanting diffusion growth chambers in the t...

Marine biotechnology (New York, N.Y.), Jan 13, 2015

Ascidians have yielded a wide variety of bioactive natural products. The colonial ascidian Eudist... more Ascidians have yielded a wide variety of bioactive natural products. The colonial ascidian Eudistoma toealensis from Micronesia has been identified as the source of a series of staurosporine derivatives, though the exact origin of these derivatives is still unknown. To identify known staurosporine-producing microbes associated with E. toealensis, we analyzed with 16S rRNA gene tag pyrosequencing the overall bacterial community and focused on potential symbiotic bacteria already known from other ascidians or other marine hosts, such as sponges. The described microbiota was one of very high diversity, comprising 43 phyla: two from archaea, 34 described bacterial phyla, and seven candidate bacterial phyla. Many bacteria, which are renowned community members of other ascidians and marine holobionts, such as sponges and corals, were also part of the E. toealensis microbial community. Furthermore, two known producers of indolocarbazoles, Salinispora and Verrucosispora, were found with hig...

The Biological bulletin, 2014

The dichotomy between high microbial abundance (HMA) and low microbial abundance (LMA) sponges ha... more The dichotomy between high microbial abundance (HMA) and low microbial abundance (LMA) sponges has been long recognized. In the present study, 56 sponge species from three geographic regions (greater Caribbean, Mediterranean, Red Sea) were investigated by transmission electron microscopy for the presence of microorganisms in the mesohyl matrix. Additionally, bacterial enumeration by DAPI-counting was performed on a subset of samples. Of the 56 species investigated, 28 were identified as belonging to the HMA and 28 to the LMA category. The sponge orders Agelasida and Verongida consisted exclusively of HMA species, and the Poecilosclerida were composed only of LMA sponges. Other taxa contained both types of microbial associations (e.g., marine Haplosclerida, Homoscleromorpha, Dictyoceratida), and a clear phylogenetic pattern could not be identified. For a few sponge species, an intermediate microbial load was determined, and the microscopy data did not suffice to reliably determine HM...

The filamentous proteobacterium 'Candidatus Entotheonella palauensis' is a member of the ... more The filamentous proteobacterium 'Candidatus Entotheonella palauensis' is a member of the microbial mesohyl community associated with the two lithistid sponges Theonella swinhoei and Discodermia sp. (both class Demospongiae, order Lithistida, family Theonellidae). The bacterium is one of the few presumably known microbial sponge-symbionts and its presence within the mesohyl is closely related with the availability of the secondary metabolites theopalauamide and discodermolide within the sponges. However, due to the limited distribution across the sponge hosts very little is known about the ecology, diversity, relative abundance, and phylogeography of E. palauensis. Furthermore, there is no information about the evolution and maintenance of the symbiotic relationship between the bacteria and the hosts. So far, both evolutionary modes, the vertical transmission or the acquisition from the rare seawater biosphere (i.e. horizontal transmission), are possible pathways. The aim of ...

Sponges are well known for their diverse and species-specific bacterial communities, with some of... more Sponges are well known for their diverse and species-specific bacterial communities, with some of these bacteria producing bioactive compounds that are of pharmacological interest. However, most of these bacteria resisted cultivation due to complex biochemical and metabolic host-specific interactions that are not reproducible using common cultivation procedures. We therefore recently adopted the diffusion-growth-chamber (DGC) technique in a bid to isolate these rare, uncultured sponge-associated bacteria. Semi-permeable growth chambers containing sponge homogenate-enriched medium were placed in the reef sponge Rhabdastrella globostellata with the aim to culture previously uncultivated sponge-specific bacteria in situ. By utilizing the DGC method it was possible, for the first time, to cultivate in vivo in sponges and subsequently isolate known and novel bacteria in vitro. More than 270 16S rRNA gene sequences were obtained during this study. BLAST analysis of sequences against the N...

Palaeogeogr Palaeoclimatol, 2002

Analysis of the Papua New Guinean sponge Theonella swinhoei afforded a new calyculinamide-related... more Analysis of the Papua New Guinean sponge Theonella swinhoei afforded a new calyculinamide-related congener for which we propose the name swinhoeiamide A (1). The structure of the new compound was unambiguously established on the basis of NMR spectroscopic ( 1 H, 13 C, COSY, HMBC) and mass spectrometric (FABMS) data. Swinhoeiamide A exhibited insecticidal activity toward neonate larvae of the polyphagous pest insect Spodoptera littoralis when incorporated in an artificial diet offered to the larvae in a chronic feeding bioassay (ED 50 2.11 ppm, LD 50 2.98 ppm). Furthermore, it was found to be fungicidal against Candida albicans and Aspergillus fumigatus (MIC 1.2 and 1.0 µg/mL, respectively).

Applied and Environmental Microbiology, 2004

Información del artículo Evidence for Acyl Homoserien Lactone Signal Production in Bacteria Assoc... more Información del artículo Evidence for Acyl Homoserien Lactone Signal Production in Bacteria Associated with Marine Sponges.

Phys Rev D, Mar 17, 2011

Photon-neutrino interactions arise quite naturally in noncommutative field theories. Such couplin... more Photon-neutrino interactions arise quite naturally in noncommutative field theories. Such couplings are absent in ordinary field theory and imply experimental lower bounds on the energy scale ΛNC˜|θ|-2 of noncommutativity. Using nonperturbative methods and a Seiberg-Witten map based covariant approach to noncommutative gauge theory, we obtain θ-exact expressions for the interactions, thereby eliminating previous restrictions to low-energy phenomena. We discuss implications for plasmon decay, neutrino charge radii, big bang nucleosynthesis, and ultrahigh energy cosmic rays. Our results behave reasonably throughout all interaction energy scales, thus facilitating further phenomenological applications.

Journal of natural products, Jan 9, 2015

Phyllodesmium is a tropical marine slug genus with about 30 described species. None of them have ... more Phyllodesmium is a tropical marine slug genus with about 30 described species. None of them have a protective shell, and all of them feed on octocorals that are generally known to provide defensive compounds and thus help to defend the naked slugs against sympatric predators, such as fish, crabs, cephalopods, and echinoderms. Phyllodesmium longicirrum is the species that grows the biggest and that is least protected by camouflage on its respective food, usually a soft coral of the genus Sarcophyton. Investigation of the lipophilic extract of a single specimen of P. longicirrum from the Great Barrier Reef (Australia) led to the isolation of four new polycyclic diterpenes. Compound 1 showed significant deterrent activity in a fish feeding assay.

Journal of Experimental Marine Biology and Ecology, Mar 1, 2011

Sponges have evolved a variety of chemical and structural defense mechanisms to avoid predation. ... more Sponges have evolved a variety of chemical and structural defense mechanisms to avoid predation. While chemical defense is well established in sponges, studies on structural defense are rare and with ambiguous results. We used field and laboratory experiments to investigate predation patterns and the anti-predatory defense mechanisms of the sponge Melophlus sarasinorum, a common inhabitant of Indo-pacific coral reefs. Specifically, we aimed to investigate whether M. sarasinorum is chemically or structurally defended against predation and if the defenses are expressed differently in the ectosomal and choanosomal tissue of the sponge. Chemical defense was measured as feeding deterrence, structural defense as feeding deterrence and toughness. Our results demonstrated that chemical defense is evenly distributed throughout the sponge and works in conjunction with a structurally defended ectosome to further reduce predation levels. The choanosome of the sponge contained higher protein levels, but revealed no structural defense. We conclude that the equal distribution of chemical defenses throughout M. sarasinorum is in accordance with Optimal Defense Theory (ODT) in regards to fish predation, while structural defense supports ODT by being restricted to the surface layer which experiences the highest predation risks from mesograzers.

PLOS ONE, 2015

Sponges and other sessile invertebrates are lacking behavioural escape or defense mechanisms and ... more Sponges and other sessile invertebrates are lacking behavioural escape or defense mechanisms and rely therefore on morphological or chemical defenses. Studies from terrestrial systems and marine algae demonstrated facultative defenses like induction and activation to be common, suggesting that sessile marine organisms also evolved mechanisms to increase the efficiency of their chemical defense. However, inducible defenses in sponges have not been investigated so far and studies on activated defenses are rare. We investigated whether tropical sponge species induce defenses in response to artificial predation and whether wounding triggers defense activation. Additionally, we tested if these mechanisms are also used to boost antimicrobial activity to avoid bacterial infection. Laboratory experiments with eight pacific sponge species showed that 87% of the tested species were chemically defended. Two species, Stylissa massa and Melophlus sarasinorum, induced defenses in response to simulated predation, which is the first demonstration of induced antipredatory defenses in marine sponges. One species, M. sarasinorum, also showed activated defense in response to wounding. Interestingly, 50% of the tested sponge species demonstrated induced antimicrobial defense. Simulated predation increased the antimicrobial defenses in Aplysinella sp., Cacospongia sp., M. sarasinorum, and S. massa. Our results suggest that wounding selects for induced antimicrobial defenses to protect sponges from pathogens that could otherwise invade the sponge tissue via feeding scars.

Journal of Mathematical Physics, 2014

We analyse the symmetries underlying nonassociative deformations of geometry in nongeometric R-fl... more We analyse the symmetries underlying nonassociative deformations of geometry in nongeometric R-flux compactifications which arise via T-duality from closed strings with constant geometric fluxes. Starting from the non-abelian Lie algebra of translations and Bopp shifts in phase space, together with a suitable cochain twist, we construct the quasi-Hopf algebra of symmetries that deforms the algebra of functions and the exterior differential calculus in the phase space description of nonassociative R-space. In this setting nonassociativity is characterised by the associator 3-cocycle which controls non-coassociativity of the quasi-Hopf algebra. We use abelian 2-cocycle twists to construct maps between the dynamical nonassociative star product and a family of associative star products parametrized by constant momentum surfaces in phase space. We define a suitable integration on these nonassociative spaces and find that the usual cyclicity of associative noncommutative deformations is replaced by weaker notions of 2-cyclicity and 3-cyclicity. Using this star product quantization on phase space together with 3-cyclicity, we formulate a consistent version of nonassociative quantum mechanics, in which we calculate the expectation values of area and volume operators, and find coarse-graining of the string background due to the R-flux. *

Physical Review D, 2011

Photon-neutrino interactions arise quite naturally in noncommutative field theories. Such couplin... more Photon-neutrino interactions arise quite naturally in noncommutative field theories. Such couplings are absent in ordinary field theory and imply experimental lower bounds on the energy scale Λ NC ∼ |θ| −2 of noncommutativity. Using non-perturbative methods and a Seiberg-Witten map based covariant approach to noncommutative gauge theory, we obtain θ-exact expressions for the interactions, thereby eliminating previous restrictions to low-energy phenomena. We discuss implications for plasmon decay, neutrino charge radii, big bang nucleosynthesis and ultrahigh energy cosmic rays. Our results behave reasonably throughout all interaction energy scales, thus facilitating further phenomenological applications.

Journal of natural products, 2003

Chemical investigation of the Micronesian ascidian Eudistoma sp. afforded two new eudistomin cong... more Chemical investigation of the Micronesian ascidian Eudistoma sp. afforded two new eudistomin congeners, which were designated eudistomins W (1) and X (2). The structures of the new compounds were unambiguously established on the basis of NMR spectroscopic ((1)H, (13)C, COSY, (1)H detected direct, and long-range (13)C-(1)H correlations) and mass spectrometric (EI and ESIMS) data. Compound 2 exhibited antibiotic activity toward Bacillus subtilis, Staphyloccocus aureus, and Escherichia coli and was also found to be fungicidal against Candida albicans in an agar diffusion assay. Compound 1 was selectively active against C. albicans but showed no antibacterial activity.

Natural product communications, 2009

The cancer chemopreventive and cytotoxic properties of 50 extracts derived from Twilight Zone (50... more The cancer chemopreventive and cytotoxic properties of 50 extracts derived from Twilight Zone (50-150 m) sponges, gorgonians and associated bacteria, together with 15 extracts from shallow water hard corals, as well as 16 fractions derived from the methanol solubles of the Twilight Zone sponge Suberea sp, were assessed in a series of bioassays. These assays included: Induction of quinone reductase (QR), inhibition of TNF-alpha activated nuclear factor kappa B (NFkappaB), inhibition of aromatase, interaction with retinoid X receptor (RXR), inhibition of nitric oxide (NO) synthase, inhibition 2,2-diphenyl-1-picrylhydrazyl radical scavenging (DPPH), and inhibition of HL-60 and MCF-7 cell proliferation. The results of these assays showed that at least 10 extracts and five fractions inhibited NFkappaB by greater than 60%, two extracts and two fractions inhibited DPPH by more than 50%, nine extracts and two fractions affected the survival of HL-60 cells, no extracts or fractions affected ...

Marine biotechnology (New York, N.Y.), 2014

Marine sponges contain dense and diverse microbial communities, which are renowned as a source of... more Marine sponges contain dense and diverse microbial communities, which are renowned as a source of bioactive metabolites. The biological activities of sponge-microbe natural products span a broad spectrum, from antibacterial and antifungal to antitumor and antiviral applications. However, the potential of sponge-derived compounds has not been fully realized, due largely to the acknowledged "supply issue." Most bacteria from environmental samples have resisted cultivation on artificial growth media, and cultivation of sponge-associated bacteria has been a major focus in the search for novel marine natural products. One approach to isolate so-called "uncultivable" microorganisms from different environments is the diffusion growth chamber method. Here, we describe the first application of diffusion growth chambers for the isolation of cultivable and previously uncultivated bacteria from sponges. The study was conducted by implanting diffusion growth chambers in the t...

Marine biotechnology (New York, N.Y.), Jan 13, 2015

Ascidians have yielded a wide variety of bioactive natural products. The colonial ascidian Eudist... more Ascidians have yielded a wide variety of bioactive natural products. The colonial ascidian Eudistoma toealensis from Micronesia has been identified as the source of a series of staurosporine derivatives, though the exact origin of these derivatives is still unknown. To identify known staurosporine-producing microbes associated with E. toealensis, we analyzed with 16S rRNA gene tag pyrosequencing the overall bacterial community and focused on potential symbiotic bacteria already known from other ascidians or other marine hosts, such as sponges. The described microbiota was one of very high diversity, comprising 43 phyla: two from archaea, 34 described bacterial phyla, and seven candidate bacterial phyla. Many bacteria, which are renowned community members of other ascidians and marine holobionts, such as sponges and corals, were also part of the E. toealensis microbial community. Furthermore, two known producers of indolocarbazoles, Salinispora and Verrucosispora, were found with hig...

The Biological bulletin, 2014

The dichotomy between high microbial abundance (HMA) and low microbial abundance (LMA) sponges ha... more The dichotomy between high microbial abundance (HMA) and low microbial abundance (LMA) sponges has been long recognized. In the present study, 56 sponge species from three geographic regions (greater Caribbean, Mediterranean, Red Sea) were investigated by transmission electron microscopy for the presence of microorganisms in the mesohyl matrix. Additionally, bacterial enumeration by DAPI-counting was performed on a subset of samples. Of the 56 species investigated, 28 were identified as belonging to the HMA and 28 to the LMA category. The sponge orders Agelasida and Verongida consisted exclusively of HMA species, and the Poecilosclerida were composed only of LMA sponges. Other taxa contained both types of microbial associations (e.g., marine Haplosclerida, Homoscleromorpha, Dictyoceratida), and a clear phylogenetic pattern could not be identified. For a few sponge species, an intermediate microbial load was determined, and the microscopy data did not suffice to reliably determine HM...

The filamentous proteobacterium 'Candidatus Entotheonella palauensis' is a member of the ... more The filamentous proteobacterium 'Candidatus Entotheonella palauensis' is a member of the microbial mesohyl community associated with the two lithistid sponges Theonella swinhoei and Discodermia sp. (both class Demospongiae, order Lithistida, family Theonellidae). The bacterium is one of the few presumably known microbial sponge-symbionts and its presence within the mesohyl is closely related with the availability of the secondary metabolites theopalauamide and discodermolide within the sponges. However, due to the limited distribution across the sponge hosts very little is known about the ecology, diversity, relative abundance, and phylogeography of E. palauensis. Furthermore, there is no information about the evolution and maintenance of the symbiotic relationship between the bacteria and the hosts. So far, both evolutionary modes, the vertical transmission or the acquisition from the rare seawater biosphere (i.e. horizontal transmission), are possible pathways. The aim of ...

Sponges are well known for their diverse and species-specific bacterial communities, with some of... more Sponges are well known for their diverse and species-specific bacterial communities, with some of these bacteria producing bioactive compounds that are of pharmacological interest. However, most of these bacteria resisted cultivation due to complex biochemical and metabolic host-specific interactions that are not reproducible using common cultivation procedures. We therefore recently adopted the diffusion-growth-chamber (DGC) technique in a bid to isolate these rare, uncultured sponge-associated bacteria. Semi-permeable growth chambers containing sponge homogenate-enriched medium were placed in the reef sponge Rhabdastrella globostellata with the aim to culture previously uncultivated sponge-specific bacteria in situ. By utilizing the DGC method it was possible, for the first time, to cultivate in vivo in sponges and subsequently isolate known and novel bacteria in vitro. More than 270 16S rRNA gene sequences were obtained during this study. BLAST analysis of sequences against the N...