The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform
Dimitri D. Deheyn - One of the best experts on this subject based on the ideXlab platform.
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Marine Worm bioluminescence is slowly revealing its secrets
The FASEB Journal, 2019Co-Authors: Evelien De Meulenaere, Dimitri D. DeheynAbstract:The natural phenomenon of bioluminescence is light production fueled by biochemical processes. In general, bioluminescence is observed as very short (millisecond) flashes, or a lasting glow in bact...
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active microrheology determines scale dependent material properties of chaetopterus mucus
PLOS ONE, 2017Co-Authors: William Weigand, Dimitri D. Deheyn, Daniel L. Blair, A Messmore, A Moralessanz, J S Urbach, Rae M RobertsonandersonAbstract:We characterize the lengthscale-dependent rheological properties of mucus from the ubiquitous Chaetopterus Marine Worm. We use optically trapped probes (2-10 μm) to induce microscopic strains and measure the stress response as a function of oscillation amplitude. Our results show that viscoelastic properties are highly dependent on strain scale (l), indicating three distinct lengthscale-dependent regimes at l1 ≤4 μm, l2≈4-10 μm, and l3≥10 μm. While mucus response is similar to water for l1, suggesting that probes rarely contact the mucus mesh, the response for l2 is distinctly more viscous and independent of probe size, indicative of continuum mechanics. Only for l3 does the response match the macroscopic elasticity, likely due to additional stiffer constraints that strongly resist probe displacement. Our results suggest that, rather than a single lengthscale governing crossover from viscous to elastic, mucus responds as a hierarchical network with a loose biopolymer mesh coupled to a larger scaffold responsible for macroscopic gel-like mechanics.
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Evidence that ferritin is associated with light production in the mucus of the Marine Worm Chaetopterus.
Scientific Reports, 2016Co-Authors: Renu Rawat, Dimitri D. DeheynAbstract:The blue glow of the mucus from Chaetopterus involves a photoprotein, iron and flavins. Identity and respective role of these components remain, however, largely unresolved today, likely because of viscosity issues and inhibition of this system by oxidizers conventionally used to track bioluminescence activity. Here, we used gentle centrifugation to obtain a mucus supernatant showing no inhibition to oxidizers, allowing for further analysis. We applied conventional chromatographic techniques to isolate major proteins associated with light emission. Luminescence ability of elutriate fractions was tested with hydrogen peroxide to track photoprotein and/or protein-bound chromophore. Fractions producing light contained few major proteins, one with similarity to ferritin. Addition to the mucus of elements with inhibitory/potentiary effect on ferritin ferroxidase activity induced corresponding changes in light production, emphasizing the possible role of ferritin in the Worm bioluminescence. DNA of the protein was cloned, sequenced, and expressed, confirming its identity to a Chaetopterus Ferritin (ChF). Both ferric and ferrous iron were found in the mucus, indicating the occurrence of both oxidase and reductase activity. Biochemical analysis showed ChF has strong ferroxidase activity, which could be a source of biological iron and catalytic energy for the Worm bioluminescence when coupled to a reduction process with flavins.
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The biocomposite tube of a chaetopterid Marine Worm constructed with highly-controlled orientation of nanofilaments
Materials Science and Engineering C, 2015Co-Authors: Darshil U Shah, John Stires, Fritz Vollrath, Dimitri D. DeheynAbstract:The ultrastructure of the self-constructed tube housing of the bioluminescent Marine Worm, Chaetopterus sp. reveals that the bio-nanocomposite tube comprises of multiple non-woven plies of multi-axially oriented organic nanofilaments (ø 50-1100 nm) cemented together by an unstructured organic matrix binder. The thin-walled, impermeable tubes are bio-inspirational for conventional pipe technology. Orientation distribution analyses revealed that the dominant orientation angles of nanofilaments in the tube were 0°, ± 45° and ± 65°, which correlate well with optimal winding angles for 'man-made' fibre reinforced composite pipes subjected to specific loading conditions. Such a use of high aspect ratio nanofilaments in multi-axial laminates would impart toughness and flexibility to the tube structure, and facilitate rapid tube growth. While the tube production mechanism is not entirely known at this stage, our time-lapse studies show that, contrary to generic assumptions in literature, the Worm actively, rapidly and sporadically produces and expands the tube.
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housing tubes from the Marine Worm chaetopterus sp biomaterials with exceptionally broad thermomechanical properties
Journal of the Royal Society Interface, 2014Co-Authors: Darshil U Shah, John Stires, Fritz Vollrath, David Porter, Dimitri D. DeheynAbstract:The housing tube material of the Marine Worm Chaetopterus sp. exhibits thermal stability up to 250°C, similar to other biological materials such as mulberry silkWorm cocoons. Interestingly, however, dynamic mechanical thermal analysis conducted in both air and water elucidated the lack of a glass transition in the organic tube wall material. In fact, the viscoelastic properties of the anhydrous and undried tube were remarkably stable (i.e. constant and reversible) between –75°C and 200°C in air, and 5°C and 75°C in water, respectively. Moreover, it was found that hydration and associated-water plasticization were key to the rubber-like flexible properties of the tube; dehydration transformed the material behaviour to glass-like. The tube is made of bionanocomposite fibrils in highly oriented arrangement, which we argue favours the biomaterial to be highly crystalline or cross-linked, with extensive hydrogen and/or covalent bonds. Mechanical property characterization in the longitudinal and transverse directions ascertained that the tubes were not quasi-isotropic structures. In general, the higher stiffness and strength in the transverse direction implied that there were more nanofibrils orientated at ±45° and ±65° than at 0° to the tube axis. The order of the mechanical properties of the soft–tough tubes was similar to synthetic rubber-like elastomers and even some viscid silks. The complex structure–property relations observed indicated that the Worm has evolved to produce a tubular housing structure which can (i) function stably over a broad range of temperatures, (ii) endure mechanical stresses from specific planes/axes, and (iii) facilitate rapid growth or repair.
Nicole Dubilier - One of the best experts on this subject based on the ideXlab platform.
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fidelity varies in the symbiosis between a gutless Marine Worm and its microbial consortium
bioRxiv, 2021Co-Authors: Yui Sato, Juliane Wippler, Cecilia Wentrup, Nicole Dubilier, Rebecca Ansorge, Miriam Sadowski, Harald R Grubervodicka, Manuel KleinerAbstract:In obligate symbioses, partner fidelity plays a central role in maintaining the stability of the association across multiple host generations. Fidelity has been well studied in hosts with a very restricted diversity of symbionts, but little is known about how fidelity is maintained in hosts with multiple co-occurring symbionts. The Marine annelid Olavius algarvensis lives in an obligate association with at least five co-occurring bacterial symbionts that are inherited vertically. The symbionts so efficiently supply their hosts with nutrition that these Worms have completely reduced their mouth and digestive tract. Here, we investigated partner fidelity in the O. algarvensis symbiosis by sequencing the metagenomes of 80 host individuals from two mitochondrial lineages and two locations in the Mediterranean. Comparative phylogenetic analyses of mitochondrial and symbiont genotypes based on single nucleotide polymorphisms revealed high fidelity for the primary symbiont that dominated the microbial consortium of all 80 O. algarvensis individuals. In contrast, the secondary symbionts of O. algarvensis, which occurred in lower abundance and were not always present in all host individuals, showed only intermediate to low fidelity. We hypothesize that harbouring symbionts with variable levels of fidelity ensures faithful transmission of the most abundant and nutritionally important symbiont, while flexibility in the acquisition of secondary symbionts enhances genetic exchange and retains ecological and evolutionary adaptability.
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high quality draft genome sequences of the uncultured delta3 endosymbiont deltaproteobacteria assembled from metagenomes of the gutless Marine Worm olavius algarvensis
Microbiology Resource Announcements, 2020Co-Authors: Yui Sato, Tanja Woyke, Juliane Wippler, Cecilia Wentrup, Nicole Dubilier, Manuel KleinerAbstract:Here, we present two high-quality, draft metagenome-assembled genomes of deltaproteobacterial OalgDelta3 endosymbionts from the gutless Marine Worm Olavius algarvensis Their 16S rRNA gene sequences share 98% identity with Delta3 endosymbionts of related host species Olavius ilvae (GenBank accession no. AJ620501) and Inanidrilus exumae (GenBank accession no. FM202060), for which no symbiont genomes are available.
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acquisition of a novel sulfur oxidizing symbiont in the gutless Marine Worm inanidrilus exumae
Applied and Environmental Microbiology, 2018Co-Authors: Claudia Bergin, Cecilia Wentrup, Christer Erseus, Nancy Brewig, Anna Blazejak, Olav Giere, Markus Schmid, P De Wit, Nicole DubilierAbstract:ABSTRACT Gutless phallodrilines are Marine annelid Worms without a mouth or gut, which live in an obligate association with multiple bacterial endosymbionts that supply them with nutrition. In this study, we discovered an unusual symbiont community in the gutless phallodriline Inanidrilus exumae that differs markedly from the microbiomes of all 22 of the other host species examined. Comparative 16S rRNA gene sequence analysis and fluorescence in situ hybridization revealed that I. exumae harbors cooccurring gamma-, alpha-, and deltaproteobacterial symbionts, while all other known host species harbor gamma- and either alpha- or deltaproteobacterial symbionts. Surprisingly, the primary chemoautotrophic sulfur oxidizer “Candidatus Thiosymbion” that occurs in all other gutless phallodriline hosts does not appear to be present in I. exumae. Instead, I. exumae harbors a bacterial endosymbiont that resembles “ Ca . Thiosymbion” morphologically and metabolically but originates from a novel lineage within the class Gammaproteobacteria. This endosymbiont, named Gamma 4 symbiont here, had a 16S rRNA gene sequence that differed by at least 7% from those of other free-living and symbiotic bacteria and by 10% from that of “ Ca . Thiosymbion.” Sulfur globules in the Gamma 4 symbiont cells, as well as the presence of genes characteristic for autotrophy ( cbbL ) and sulfur oxidation ( aprA ), indicate that this symbiont is a chemoautotrophic sulfur oxidizer. Our results suggest that a novel lineage of free-living bacteria was able to establish a stable and specific association with I. exumae and appears to have displaced the “ Ca . Thiosymbion” symbionts originally associated with these hosts. IMPORTANCE All 22 gutless Marine phallodriline species examined to date live in a highly specific association with endosymbiotic, chemoautotrophic sulfur oxidizers called “ Ca . Thiosymbion.” These symbionts evolved from a single common ancestor and represent the ancestral trait for this host group. They are transmitted vertically and assumed to be in transition to becoming obligate endosymbionts. It is therefore surprising that despite this ancient, evolutionary relationship between phallodriline hosts and “ Ca . Thiosymbion,” these symbionts are apparently no longer present in Inanidrilus exumae. They appear to have been displaced by a novel lineage of sulfur-oxidizing bacteria only very distantly related to “ Ca . Thiosymbion.” Thus, this study highlights the remarkable plasticity of both animals and bacteria in establishing beneficial associations: the phallodriline hosts were able to acquire and maintain symbionts from two very different lineages of bacteria, while sulfur-oxidizing bacteria from two very distantly related lineages were able to independently establish symbiotic relationships with phallodriline hosts.
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transcriptomic and proteomic insights into innate immunity and adaptations to a symbiotic lifestyle in the gutless Marine Worm olavius algarvensis
BMC Genomics, 2016Co-Authors: Juliane Wippler, Manuel Kleiner, Christian Lott, Alexander Gruhl, Paul E Abraham, Richard J Giannone, Jacque Young, Robert L Hettich, Nicole DubilierAbstract:The gutless Marine Worm Olavius algarvensis has a completely reduced digestive and excretory system, and lives in an obligate nutritional symbiosis with bacterial symbionts. While considerable knowledge has been gained of the symbionts, the host has remained largely unstudied. Here, we generated transcriptomes and proteomes of O. algarvensis to better understand how this annelid Worm gains nutrition from its symbionts, how it adapted physiologically to a symbiotic lifestyle, and how its innate immune system recognizes and responds to its symbiotic microbiota. Key adaptations to the symbiosis include (i) the expression of gut-specific digestive enzymes despite the absence of a gut, most likely for the digestion of symbionts in the host's epidermal cells; (ii) a modified hemoglobin that may bind hydrogen sulfide produced by two of the Worm’s symbionts; and (iii) the expression of a very abundant protein for oxygen storage, hemerythrin, that could provide oxygen to the symbionts and the host under anoxic conditions. Additionally, we identified a large repertoire of proteins involved in interactions between the Worm's innate immune system and its symbiotic microbiota, such as peptidoglycan recognition proteins, lectins, fibrinogen-related proteins, Toll and scavenger receptors, and antimicrobial proteins. We show how this Worm, over the course of evolutionary time, has modified widely-used proteins and changed their expression patterns in adaptation to its symbiotic lifestyle and describe expressed components of the innate immune system in a Marine oligochaete. Our results provide further support for the recent realization that animals have evolved within the context of their associations with microbes and that their adaptive responses to symbiotic microbiota have led to biological innovations.
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gamma and epsilonproteobacterial ectosymbionts of a shallow water Marine Worm are related to deep sea hydrothermal vent ectosymbionts
Environmental Microbiology, 2010Co-Authors: Caroline Ruehland, Nicole DubilierAbstract:Summary The Marine oligochaete Worm Tubificoides benedii is often found in high numbers in eutrophic coastal sediments with low oxygen and high sulfide concentrations. A dense biofilm of filamentous bacteria on the Worm's tail end were morphologically described over 20 years ago, but no further studies of these epibiotic associations were done. In this study, we used fluorescence in situ hybridization and comparative sequence analysis of 16S rRNA and protein-coding genes to characterize the microbial community of the Worm's tail ends. The presence of genes involved in chemoautotrophy (cbbL and cbbM) and sulfur metabolism (aprA) indicated the potential of the T. benedii microbial community for chemosynthesis. Two filamentous ectosymbionts were specific to the Worm's tail ends: one belonged to the Leucothrix mucor clade within the Gammaproteobacteria and the other to the Thiovulgaceae within the Epsilonproteobacteria. Both T. benedii ectosymbionts belonged to clades that consisted almost exclusively of bacteria associated with invertebrates from deep-sea hydrothermal vents. Such close relationships between symbionts from shallow-water and deep-sea hosts that are not closely related to each other are unusual, and indicate that biogeography and host affiliation did not play a role in these associations. Instead, similarities between the dynamic environments of vents and organic-rich mudflats with their strong fluctuations in reductants and oxidants may have been the driving force behind the establishment and evolution of these symbioses.
Stephen A Stricker - One of the best experts on this subject based on the ideXlab platform.
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potential upstream regulators and downstream targets of amp activated kinase signaling during oocyte maturation in a Marine Worm
Reproduction, 2011Co-Authors: Stephen A StrickerAbstract:Unlike in mice, where the onset of oocyte maturation (germinal vesicle breakdown, GVBD) is blocked by cAMP and triggered by AMP-activated kinase (AMPK), oocytes of the Marine nemertean Worm Cerebratulus undergo GVBD in response to cAMP elevations and AMPK deactivation. Since the pathways underlying AMPK's effects on mammalian or nemertean GVBD have not been fully defined, follicle-free nemertean oocytes were treated with pharmacological modulators and subsequently analyzed via immunoblotting methods using phospho-specific antibodies to potential regulators and targets of AMPK. Based on such phosphorylation patterns, immature oocytes possessed an active LKB1-like kinase that phosphorylated AMPK's T172 site to activate AMPK, whereas during oocyte maturation, AMPK and LKB1-like activities declined. In addition, given that MAPK can deactivate AMPK in somatic cells, oocytes were treated with inhibitors of ERK1/2 MAPK activation. However, these assays indicated that T172 dephosphorylation during maturation-associated AMPK deactivation did not require MAPK and that an observed inhibition of GVBD elicited by the MAPK kinase blocker U0126 was actually due to ectopic AMPK activation rather than MAPK inactivation. Similarly, based on tests using an inhibitor of maturation-promoting factor (MPF), T172 dephosphorylation occurred upstream to, and independently of, MPF activation. Alternatively, active MPF and MAPK were necessary for fully phosphorylating a presumably inhibitory S485/491 site on AMPK. Furthermore, in assessing signals possibly linking AMPK deactivation to MPF activation, evidence was obtained for maturing oocytes upregulating target-of-rapamycin activity and downregulating the cyclin-dependent kinase inhibitor Kip1. Collectively, these findings are discussed relative to multiple pathways potentially mediating AMPK signaling during GVBD.
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roles of protein kinase c isotypes during seawater versus camp induced oocyte maturation in a Marine Worm
Molecular Reproduction and Development, 2009Co-Authors: Stephen A StrickerAbstract:Based on immunoblotting analyses using phospho-specific antibodies, follicle-free oocytes of the Marine nemertean Worm Cerebratulus sp. activate protein kinase C (PKC) when induced to mature by either seawater (SW) or cAMP-elevating drugs. In SW-stimulated oocytes, the onset of maturation (=germinal vesicle breakdown, “GVBD”) can be inhibited by broadly acting PKC antagonists such as bisindoylmaleimide (BIM)-I or BIM-IX. Conversely, co-treatment with SW solutions of BIM-I or BIM-IX plus a cAMP elevator (forskolin, serotonin, or a phosphodiesterase inhibitor) restores GVBD, indicating that the blockage of SW-induced GVBD by PKC antagonists is not simply due to oocyte morbidity and that such inhibition is somehow reversible by cAMP signaling. In tests to determine which specific PKC may be involved in regulating GVBD, immunoblots fail to provide strong evidence for the presence of conventional or novel PKCs, which are characteristically activated by 12-O-tetradecanoylphorbol-13-acetate (TPA). Moreover, inhibitors of TPA-sensitive PKCs do not prevent SW-induced GVBD, and TPA itself serves to downregulate, rather than stimulate, GVBD. Alternatively, maturing oocytes apparently possess phosphorylated forms of TPA-insensitive isotypes, including an ∼67-kDa atypical PKC and an ∼130-kDa PKC-related kinase (PRK). Accordingly, inhibitors of atypical PKC signaling block SW-but not cAMP-induced GVBD, collectively suggesting that instead of depending on a conventional or novel isotype, SW-induced GVBD may require atypical PKC and/or PRK. In addition, such findings provide further support for the view that GVBD in nemertean oocytes can be achieved via multiple mechanisms, with SW triggering different signaling pathways than are stimulated in the presence of cAMP-elevating drugs. Mol. Reprod. Dev. 76: 693–707, 2009. © 2008 Wiley-Liss, Inc.
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interactions between mitogen activated protein kinase and protein kinase c signaling during oocyte maturation and fertilization in a Marine Worm
Molecular Reproduction and Development, 2009Co-Authors: Stephen A StrickerAbstract:In the Marine nemertean Worm Cerebratulus, follicle-free oocytes re-initiate meiosis and undergo nuclear disassembly (=germinal vesicle breakdown, GVBD) after being stimulated to mature by seawater (SW) or cAMP-elevating drugs. Previously, it has been shown that inhibitors of mitogen-activated protein kinase (MAPK) or protein kinase C (PKC) signaling can reduce SW-induced GVBD in nemertean oocytes without affecting cAMP-induced GVBD. Thus, SW and cAMP elevators may trigger alternative pathways that vary in their dependence on MAPK and PKC. To further characterize such signaling cascades, immunoblotting analyses of MAPK and PKC activities were conducted on oocytes treated with U0126, an inhibitor of the MAPK kinase (MAPKK) that is responsible for activating MAPK. Based on these analyses and comparisons with the MAPKK inhibitor CI1040 that inactivates MAPK without preventing GVBD, U0126 seems to block GVBD via a non-MAPK-mediated effect that involves PKC. Moreover, evidence is presented for post-GVBD oocytes establishing positive feedback between MAPK and PKC signaling. Such feedback apparently allows the activities of both kinases to be maintained before insemination and to undergo concomitant downregulation after fertilization. Furthermore, in oocytes treated with MAPKK and PKC inhibitors during fertilization, sperm incorporation and polar body formation still occur, but normal cleavage is prevented. This suggests that although GVBD and aspects of post-fertilization activation may proceed in the absence of MAPK or PKC, such kinases are apparently required for proper embryogenesis. Collectively, these results are discussed relative to previous analyses of the interactions and functions of MAPK and PKC signaling during oocyte maturation and fertilization.
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injections of porcine sperm extracts trigger fertilization like calcium oscillations in oocytes of a Marine Worm
Experimental Cell Research, 2000Co-Authors: Stephen A Stricker, Karl Swann, Keith T Jones, Rafael A FissoreAbstract:The precise mechanisms by which sperm trigger calcium transients in eggs or oocytes during fertilization remain unknown. Based on time-lapse confocal microscopy, we show that intracellular injections of porcine sperm extracts cause the oocytes of a Marine nemertean Worm to undergo repetitive calcium oscillations resembling those obtained during normal fertilizations. Such findings are consistent with the view that fertilization involves a soluble sperm factor (SF) which is capable of eliciting calcium transients without binding to externally situated receptors on the oocyte plasmalemma. This study also describes for the first time the wave-like propagation patterns of SF-induced calcium transients that are generated in a heterologous combination of gametes obtained from different phyla of animals. Such cross-reactivity between distantly related taxa suggests that the intracellular signaling pathways triggered by sperm factors can be well conserved.
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calcium and endoplasmic reticulum dynamics during oocyte maturation and fertilization in the Marine Worm cerebratulus lacteus
Developmental Biology, 1998Co-Authors: Stephen A Stricker, Roberto Silva, Toni L SmytheAbstract:To monitor calcium and endoplasmic reticulum (ER) dynamics during oocyte maturation and fertilization, oocytes of the Marine Worm Cerebratulus lacteus were injected with the calcium-sensitive indicator calcium green dextran and/or the ER-specific probe "DiI." Based on time-lapse confocal imaging of such specimens, prophase-arrested immature oocytes failed to develop normally after insemination and typically produced non-wave-like calcium transients that were lower in amplitude and less persistent than the wave-like oscillations observed during fertilizations of mature oocytes. Accordingly, the ER of DiI-loaded immature oocytes lacked an obvious substructure, whereas ER clusters, or "microdomains," began to form in maturing specimens at about the time that these oocytes became competent to undergo normal fertilization-induced calcium dynamics and cleavage. The ER microdomains of mature oocytes typically reached widths of 1-8 micrometer and disappeared approximately 1 h after fertilization, which in turn coincided with the termination of the calcium oscillations. Collectively, these findings indicate: (i) changes in ER structure are temporally correlated with the onset and cessation of the calcium oscillations required for subsequent cleavage, and (ii) such ER reorganizations may play an important role in early development by enabling mature oocytes to generate a normal calcium response.
Manuel Kleiner - One of the best experts on this subject based on the ideXlab platform.
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fidelity varies in the symbiosis between a gutless Marine Worm and its microbial consortium
bioRxiv, 2021Co-Authors: Yui Sato, Juliane Wippler, Cecilia Wentrup, Nicole Dubilier, Rebecca Ansorge, Miriam Sadowski, Harald R Grubervodicka, Manuel KleinerAbstract:In obligate symbioses, partner fidelity plays a central role in maintaining the stability of the association across multiple host generations. Fidelity has been well studied in hosts with a very restricted diversity of symbionts, but little is known about how fidelity is maintained in hosts with multiple co-occurring symbionts. The Marine annelid Olavius algarvensis lives in an obligate association with at least five co-occurring bacterial symbionts that are inherited vertically. The symbionts so efficiently supply their hosts with nutrition that these Worms have completely reduced their mouth and digestive tract. Here, we investigated partner fidelity in the O. algarvensis symbiosis by sequencing the metagenomes of 80 host individuals from two mitochondrial lineages and two locations in the Mediterranean. Comparative phylogenetic analyses of mitochondrial and symbiont genotypes based on single nucleotide polymorphisms revealed high fidelity for the primary symbiont that dominated the microbial consortium of all 80 O. algarvensis individuals. In contrast, the secondary symbionts of O. algarvensis, which occurred in lower abundance and were not always present in all host individuals, showed only intermediate to low fidelity. We hypothesize that harbouring symbionts with variable levels of fidelity ensures faithful transmission of the most abundant and nutritionally important symbiont, while flexibility in the acquisition of secondary symbionts enhances genetic exchange and retains ecological and evolutionary adaptability.
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high quality draft genome sequences of the uncultured delta3 endosymbiont deltaproteobacteria assembled from metagenomes of the gutless Marine Worm olavius algarvensis
Microbiology Resource Announcements, 2020Co-Authors: Yui Sato, Tanja Woyke, Juliane Wippler, Cecilia Wentrup, Nicole Dubilier, Manuel KleinerAbstract:Here, we present two high-quality, draft metagenome-assembled genomes of deltaproteobacterial OalgDelta3 endosymbionts from the gutless Marine Worm Olavius algarvensis Their 16S rRNA gene sequences share 98% identity with Delta3 endosymbionts of related host species Olavius ilvae (GenBank accession no. AJ620501) and Inanidrilus exumae (GenBank accession no. FM202060), for which no symbiont genomes are available.
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transcriptomic and proteomic insights into innate immunity and adaptations to a symbiotic lifestyle in the gutless Marine Worm olavius algarvensis
BMC Genomics, 2016Co-Authors: Juliane Wippler, Manuel Kleiner, Christian Lott, Alexander Gruhl, Paul E Abraham, Richard J Giannone, Jacque Young, Robert L Hettich, Nicole DubilierAbstract:The gutless Marine Worm Olavius algarvensis has a completely reduced digestive and excretory system, and lives in an obligate nutritional symbiosis with bacterial symbionts. While considerable knowledge has been gained of the symbionts, the host has remained largely unstudied. Here, we generated transcriptomes and proteomes of O. algarvensis to better understand how this annelid Worm gains nutrition from its symbionts, how it adapted physiologically to a symbiotic lifestyle, and how its innate immune system recognizes and responds to its symbiotic microbiota. Key adaptations to the symbiosis include (i) the expression of gut-specific digestive enzymes despite the absence of a gut, most likely for the digestion of symbionts in the host's epidermal cells; (ii) a modified hemoglobin that may bind hydrogen sulfide produced by two of the Worm’s symbionts; and (iii) the expression of a very abundant protein for oxygen storage, hemerythrin, that could provide oxygen to the symbionts and the host under anoxic conditions. Additionally, we identified a large repertoire of proteins involved in interactions between the Worm's innate immune system and its symbiotic microbiota, such as peptidoglycan recognition proteins, lectins, fibrinogen-related proteins, Toll and scavenger receptors, and antimicrobial proteins. We show how this Worm, over the course of evolutionary time, has modified widely-used proteins and changed their expression patterns in adaptation to its symbiotic lifestyle and describe expressed components of the innate immune system in a Marine oligochaete. Our results provide further support for the recent realization that animals have evolved within the context of their associations with microbes and that their adaptive responses to symbiotic microbiota have led to biological innovations.
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metaproteomics of a gutless Marine Worm and its symbiotic microbial community reveal unusual pathways for carbon and energy use
Proceedings of the National Academy of Sciences of the United States of America, 2012Co-Authors: Manuel Kleiner, Cecilia Wentrup, Christian Lott, Hanno Teeling, Silke Wetzel, Jacque C Young, Yunjuan Chang, Manesh Shah, Nathan C Verberkmoes, Jan ZarzyckiAbstract:Low nutrient and energy availability has led to the evolution of numerous strategies for overcoming these limitations, of which symbiotic associations represent a key mechanism. Particularly striking are the associations between chemosynthetic bacteria and Marine animals that thrive in nutrient-poor environments such as the deep sea because the symbionts allow their hosts to grow on inorganic energy and carbon sources such as sulfide and CO2. Remarkably little is known about the physiological strategies that enable chemosynthetic symbioses to colonize oligotrophic environments. In this study, we used metaproteomics and metabolomics to investigate the intricate network of metabolic interactions in the chemosynthetic association between Olavius algarvensis, a gutless Marine Worm, and its bacterial symbionts. We propose previously undescribed pathways for coping with energy and nutrient limitation, some of which may be widespread in both free-living and symbiotic bacteria. These pathways include (i) a pathway for symbiont assimilation of the host waste products acetate, propionate, succinate and malate; (ii) the potential use of carbon monoxide as an energy source, a substrate previously not known to play a role in Marine invertebrate symbioses; (iii) the potential use of hydrogen as an energy source; (iv) the strong expression of high-affinity uptake transporters; and (v) as yet undescribed energy-efficient steps in CO2 fixation and sulfate reduction. The high expression of proteins involved in pathways for energy and carbon uptake and conservation in the O. algarvensis symbiosis indicates that the oligotrophic nature of its environment exerted a strong selective pressure in shaping these associations.
Darshil U Shah - One of the best experts on this subject based on the ideXlab platform.
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The biocomposite tube of a chaetopterid Marine Worm constructed with highly-controlled orientation of nanofilaments
Materials Science and Engineering C, 2015Co-Authors: Darshil U Shah, John Stires, Fritz Vollrath, Dimitri D. DeheynAbstract:The ultrastructure of the self-constructed tube housing of the bioluminescent Marine Worm, Chaetopterus sp. reveals that the bio-nanocomposite tube comprises of multiple non-woven plies of multi-axially oriented organic nanofilaments (ø 50-1100 nm) cemented together by an unstructured organic matrix binder. The thin-walled, impermeable tubes are bio-inspirational for conventional pipe technology. Orientation distribution analyses revealed that the dominant orientation angles of nanofilaments in the tube were 0°, ± 45° and ± 65°, which correlate well with optimal winding angles for 'man-made' fibre reinforced composite pipes subjected to specific loading conditions. Such a use of high aspect ratio nanofilaments in multi-axial laminates would impart toughness and flexibility to the tube structure, and facilitate rapid tube growth. While the tube production mechanism is not entirely known at this stage, our time-lapse studies show that, contrary to generic assumptions in literature, the Worm actively, rapidly and sporadically produces and expands the tube.
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housing tubes from the Marine Worm chaetopterus sp biomaterials with exceptionally broad thermomechanical properties
Journal of the Royal Society Interface, 2014Co-Authors: Darshil U Shah, John Stires, Fritz Vollrath, David Porter, Dimitri D. DeheynAbstract:The housing tube material of the Marine Worm Chaetopterus sp. exhibits thermal stability up to 250°C, similar to other biological materials such as mulberry silkWorm cocoons. Interestingly, however, dynamic mechanical thermal analysis conducted in both air and water elucidated the lack of a glass transition in the organic tube wall material. In fact, the viscoelastic properties of the anhydrous and undried tube were remarkably stable (i.e. constant and reversible) between –75°C and 200°C in air, and 5°C and 75°C in water, respectively. Moreover, it was found that hydration and associated-water plasticization were key to the rubber-like flexible properties of the tube; dehydration transformed the material behaviour to glass-like. The tube is made of bionanocomposite fibrils in highly oriented arrangement, which we argue favours the biomaterial to be highly crystalline or cross-linked, with extensive hydrogen and/or covalent bonds. Mechanical property characterization in the longitudinal and transverse directions ascertained that the tubes were not quasi-isotropic structures. In general, the higher stiffness and strength in the transverse direction implied that there were more nanofibrils orientated at ±45° and ±65° than at 0° to the tube axis. The order of the mechanical properties of the soft–tough tubes was similar to synthetic rubber-like elastomers and even some viscid silks. The complex structure–property relations observed indicated that the Worm has evolved to produce a tubular housing structure which can (i) function stably over a broad range of temperatures, (ii) endure mechanical stresses from specific planes/axes, and (iii) facilitate rapid growth or repair.