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Teredinidae is a family of bivalves occupying a spatial range of brackish to open-marine benthic niches and a stratigraphic range from Jurassic to recent. The teredinid genus Kuphus occurs within the calcareous muddy stiffground to hardground as vertical to inclined calcareous tubes. The ichnogenera Teredolites and Apectoichnus encompass the borings generally produced by the teredinids/shipworms. In the Kutch Basin, solitary teredinid borings range from the Eocene to the Early Miocene. Each subvertical boring has a calcareous wall with growth annulations on its outer surface. These tubes do not display any homeomorphic exoskeletal character. Rather, they manifest the producer's ethology of mechanical boring into the organic-rich stiffground to hardground substrates and sustenance through microbially mediated chemosymbiosis. A systematic ichnotaxonomy is presented here for the solitary 'Kuphus tubes' which are classified as a new ichnospecies: Teredolites solitarius. The taphonomic analysis of the borings is based on the size, shape, orientation, and composite secondary borings, which are used in ascertaining the depositional conditions and palaeoecology. Two distinct taphofacies, i.e. TS-A and TS-B, have been identified. The TS-A represents the in-situ vertical morphotype formed in a restricted intermittently brackish mud-dominated inner carbonate ramp setting. The TS-B represents the reworked borings redeposited along with other bioclasts in a storm-influenced lower to middle shoreface setting. [ABSTRACT FROM AUTHOR]

Abstract Background Cellulases play a key role in the enzymatic conversion of plant cell-wall polysaccharides into simple and economically relevant sugars. Thus, the discovery of novel cellulases from exotic biological niches is of great interest as they may present properties that are valuable in the biorefining of lignocellulosic biomass. Results We have characterized a glycoside hydrolase 5 (GH5) domain of a bi-catalytic GH5-GH6 multi-domain enzyme from the unusual gill endosymbiont Teredinibacter waterburyi of the wood-digesting shipworm Psiloteredo megotara. The catalytic GH5 domain, was cloned and recombinantly produced with or without a C-terminal family 10 carbohydrate-binding module (CBM). Both variants showed hydrolytic endo-activity on soluble substrates such as β-glucan, carboxymethylcellulose and konjac glucomannan, respectively. However, low activity was observed towards the crystalline form of cellulose. Interestingly, when co-incubated with a cellulose-active LPMO, a clear synergy was observed that boosted the overall hydrolysis of crystalline cellulose. The crystal structure of the GH5 catalytic domain was solved to 1.0 Å resolution and revealed a substrate binding cleft extension containing a putative + 3 subsite, which is uncommon in this enzyme family. The enzyme was active in a wide range of pH, temperatures and showed high tolerance for NaCl. Conclusions This study provides significant knowledge in the discovery of new enzymes from shipworm gill endosymbionts and sheds new light on biochemical and structural characterization of cellulolytic cellulase. Study demonstrated a boost in the hydrolytic activity of cellulase on crystalline cellulose when co-incubated with cellulose-active LPMO. These findings will be relevant for the development of future enzyme cocktails that may be useful for the biotechnological conversion of lignocellulose.

A cellulolytic, aerobic, gammaproteobacterium, designated strain Bs02T, was isolated from the gills of a marine wood-boring mollusc, Bankia setacea (Bivalvia: Teredinidae). The cells are Gram-stain-negative, slightly curved motile rods (2-5×0.4-0.6 µm) that bear a single polar flagellum and are capable of heterotrophic growth in a simple mineral medium supplemented with cellulose as a sole source of carbon and energy. Cellulose, carboxymethylcellulose, xylan, cellobiose and a variety of sugars also support growth. Strain Bs02T requires combined nitrogen for growth. Temperature, pH and salinity optima (range) for growth were 20 °C (range, 10-30 °C), 8.0 (pH 6.5-8.5) and 0.5 M NaCl (range, 0.0-0.8 M), respectively when grown on 0.5 % (w/v) galactose. Strain Bs02T does not require magnesium and calcium ion concentrations reflecting the proportions found in seawater. The genome size is approximately 4.03 Mbp and the DNA G+C content of the genome is 47.8 mol%. Phylogenetic analyses based on 16S rRNA gene sequences, and on conserved protein-coding sequences, show that strain Bs02T forms a well-supported clade with Teredinibacter turnerae. Average nucleotide identity and percentage of conserved proteins differentiate strain Bs02T from Teredinibacter turnerae at threshold values exceeding those proposed to distinguish bacterial species but not genera. These results indicate that strain Bs02T represents a novel species in the previously monotypic genus Teredinibacter for which the name Teredinibacter waterburyi sp. nov. is proposed. The strain has been deposited under accession numbers ATCC TSD-120T and KCTC 62963T.

Background: Cellulases play a key role in the enzymatic conversion of plant cell-wall polysaccharides into simple and economically relevant sugars. Thus, the discovery of novel cellulases from exotic biological niches is of great interest as they may present properties that are valuable in the biorefining of lignocellulosic biomass. Results: We have characterized a glycoside hydrolase 5 (GH5) domain of a bi-catalytic GH5-GH6 multi-domain enzyme from the unusual gill endosymbiont Teredinibacter waterburyi of the wood-digesting shipworm Psiloteredo megotara. The catalytic GH5 domain, was cloned and recombinantly produced with or without a C-terminal family 10 carbohydrate-binding module (CBM). Both variants showed hydrolytic endo-activity on soluble substrates such as β-glucan, carboxymethylcellulose and konjac glucomannan, respectively. However, low activity was observed towards the crystalline form of cellulose. Interestingly, when co-incubated with a cellulose-active LPMO, a clear synergy was observed that boosted the overall hydrolysis of crystalline cellulose. The crystal structure of the GH5 catalytic domain was solved to 1.0 Å resolution and revealed a substrate binding cleft extension containing a putative + 3 subsite, which is uncommon in this enzyme family. The enzyme was active in a wide range of pH, temperatures and showed high tolerance for NaCl. Conclusions: This study provides significant knowledge in the discovery of new enzymes from shipworm gill endosymbionts and sheds new light on biochemical and structural characterization of cellulolytic cellulase. Study demonstrated a boost in the hydrolytic activity of cellulase on crystalline cellulose when co-incubated with cellulose-active LPMO. These findings will be relevant for the development of future enzyme cocktails that may be useful for the biotechnological conversion of lignocellulose. [ABSTRACT FROM AUTHOR]

Abstract Background Shipworms are marine xylophagus bivalve molluscs, which can live on a diet solely of wood due to their ability to produce plant cell wall-degrading enzymes. Bacterial carbohydrate-active enzymes (CAZymes), synthesised by endosymbionts living in specialised shipworm cells called bacteriocytes and located in the animal’s gills, play an important role in wood digestion in shipworms. However, the main site of lignocellulose digestion within these wood-boring molluscs, which contains both endogenous lignocellulolytic enzymes and prokaryotic enzymes, is the caecum, and the mechanism by which bacterial enzymes reach the distant caecum lumen has remained so far mysterious. Here, we provide a characterisation of the path through which bacterial CAZymes produced in the gills of the shipworm Lyrodus pedicellatus reach the distant caecum to contribute to the digestion of wood. Results Through a combination of transcriptomics, proteomics, X-ray microtomography, electron microscopy studies and in vitro biochemical characterisation, we show that wood-digesting enzymes produced by symbiotic bacteria are localised not only in the gills, but also in the lumen of the food groove, a stream of mucus secreted by gill cells that carries food particles trapped by filter feeding to the mouth. Bacterial CAZymes are also present in the crystalline style and in the caecum of their shipworm host, suggesting a unique pathway by which enzymes involved in a symbiotic interaction are transported to their site of action. Finally, we characterise in vitro four new bacterial glycosyl hydrolases and a lytic polysaccharide monooxygenase identified in our transcriptomic and proteomic analyses as some of the major bacterial enzymes involved in this unusual biological system. Conclusion Based on our data, we propose that bacteria and their enzymes are transported from the gills along the food groove to the shipworm’s mouth and digestive tract, where they aid in wood digestion.

The bivalve families Teredinidae and Xylophagaidae include voracious consumers of wood in shallow-water and deep-water marine environments, respectively. The taxa are sister clades whose members consume wood as food with the aid of intracellular cellulolytic endosymbionts housed in their gills. This combination of adaptations is found in no other group of animals and was likely present in the common ancestor of both families. Despite these commonalities, the two families have followed dramatically different evolutionary paths with respect to anatomy, life history, and distribution. Here, we present 42 new mitochondrial genome sequences from Teredinidae and Xylophagaidae and show that distinct trajectories have also occurred in the evolution and organization of their mitochondrial genomes. Teredinidae display significantly greater rates of amino acid substitution but absolute conservation of protein-coding gene order, whereas Xylophagaidae display significantly less amino acid change but have undergone numerous and diverse changes in genome organization since their divergence from a common ancestor. As with many bivalves, these mitochondrial genomes encode 2 ribosomal RNAs, 12 protein-coding genes, and 22 tRNAs; atp8 was not detected. We further show that their phylogeny, as inferred from amino acid sequences of 12 concatenated mitochondrial protein-coding genes, is largely congruent with those inferred from their nuclear genomes based on 18S and 28S ribosomal RNA sequences. Our results provide a robust phylogenetic framework to explore the tempo and mode of mitochondrial genome evolution and offer directions for future phylogenetic and taxonomic studies of wood-boring bivalves. [ABSTRACT FROM AUTHOR]

Bacterial symbionts often provide critical functions for their hosts. For example, wood-boring bivalves called shipworms rely on cellulolytic endosymbionts for wood digestion. However, how the relationship between shipworms and their bacterial symbionts is formed and maintained remains unknown. Quorum sensing (QS) often plays an important role in regulating symbiotic relationships. We identified and characterized a QS system found in Teredinibacter sp. strain 2052S, a gill isolate of the wood-boring shipworm Bactronophorus cf. thoracites. We determined that 2052S produces the signal N-decanoyl-L-homoserine lactone (C10-HSL) and that this signal controls the activation of a biosynthetic gene cluster colocated in the symbiont genome that is conserved among all symbiotic Teredinibacter isolates. We subsequently identified extracellular metabolites associated with the QS regulon, including ones linked to the conserved biosynthetic gene cluster, using mass spectrometry-based molecular networking. Our results demonstrate that QS plays an important role in regulating secondary metabolism in this shipworm symbiont. This information provides a step toward deciphering the molecular details of the relationship between these symbionts and their hosts. Furthermore, because shipworm symbionts harbor vast yet underexplored biosynthetic potential, understanding how their secondary metabolism is regulated may aid future drug discovery efforts using these organisms. [ABSTRACT FROM AUTHOR]

Background: Shipworms are marine xylophagus bivalve molluscs, which can live on a diet solely of wood due to their ability to produce plant cell wall-degrading enzymes. Bacterial carbohydrate-active enzymes (CAZymes), synthesised by endosymbionts living in specialised shipworm cells called bacteriocytes and located in the animal's gills, play an important role in wood digestion in shipworms. However, the main site of lignocellulose digestion within these wood-boring molluscs, which contains both endogenous lignocellulolytic enzymes and prokaryotic enzymes, is the caecum, and the mechanism by which bacterial enzymes reach the distant caecum lumen has remained so far mysterious. Here, we provide a characterisation of the path through which bacterial CAZymes produced in the gills of the shipworm Lyrodus pedicellatus reach the distant caecum to contribute to the digestion of wood. Results: Through a combination of transcriptomics, proteomics, X-ray microtomography, electron microscopy studies and in vitro biochemical characterisation, we show that wood-digesting enzymes produced by symbiotic bacteria are localised not only in the gills, but also in the lumen of the food groove, a stream of mucus secreted by gill cells that carries food particles trapped by filter feeding to the mouth. Bacterial CAZymes are also present in the crystalline style and in the caecum of their shipworm host, suggesting a unique pathway by which enzymes involved in a symbiotic interaction are transported to their site of action. Finally, we characterise in vitro four new bacterial glycosyl hydrolases and a lytic polysaccharide monooxygenase identified in our transcriptomic and proteomic analyses as some of the major bacterial enzymes involved in this unusual biological system. Conclusion: Based on our data, we propose that bacteria and their enzymes are transported from the gills along the food groove to the shipworm's mouth and digestive tract, where they aid in wood digestion. [ABSTRACT FROM AUTHOR]

Marine wood-boring invertebrates rapidly fragment coarse woody debris in the sea. These wood borers have the ability to digest wood cellulose, but other potential food sources have been less investigated. To assess the contribution of each potential food source to the diet of wood borers, we traced seasonal and environmental changes in δ13C of shipworms cultured under the same experimental conditions and related these changes to variations in δ13C of potential food sources, i.e., wood log and particulate organic matter (POM) by using multiple linear regression models rather than the Bayesian mixing model. Based on the standardized partial regression coefficients in the model, it became clear that wood-derived organic carbon was the main carbon source for the teredinids, and POM also accounted for 37.9% of the teredinids' carbon source. Furthermore, we clarified variations in supplemental nitrogen sources for the teredinids: one species depended on both POM and wood log, whereas the other three species depended on either POM or wood log for their nitrogen source. δ13C values of another wood-boring bivalve of Martesia (Pholadidae) increase as it grows, which suggests that the bivalve switches its feeding strategy from xylophagous to filter feeding as it grows. Wood borers are known to accelerate the transfer of organic materials derived from wood logs to marine ecosystems. However, this study suggests that autochthonous production strongly contribute to the diet of marine wood borers, helping them to decompose wood logs in temperate shallow water. [ABSTRACT FROM AUTHOR]

Abstract Background The quest for novel enzymes for cellulosic biomass-degradation has recently been focussed on lytic polysaccharide monooxygenases (LPMOs/PMOs), Cu-containing proteins that catalyse the oxidative degradation of otherwise recalcitrant polysaccharides using O2 or H2O2 as a co-substrate. Results Although classical saprotrophic fungi and bacteria have been a rich source of lytic polysaccharide monooxygenases (LPMOs), we were interested to see if LPMOs from less evident bio-environments could be discovered and assessed for their cellulolytic activity in a biofuel context. In this regard, the marine shipworm Lyrodus pedicellatus represents an interesting source of new enzymes, since it must digest wood particles ingested during its natural tunnel boring behaviour and plays host to a symbiotic bacterium, Teredinibacter turnerae, the genome of which has revealed a multitude of enzymes dedicated to biomass deconstruction. Here, we show that T. turnerae encodes a cellulose-active AA10 LPMO. The 3D structure, at 1.4 Å resolution, along with its EPR spectrum is distinct from other AA10 polysaccharide monooxygenases insofar as it displays a “histidine-brace” catalytic apparatus with changes to the surrounding coordination sphere of the copper. Furthermore, TtAA10A possesses a second, surface accessible, Cu site 14 Å from the classical catalytic centre. Activity measurements show that the LPMO oxidises cellulose and thereby significantly augments the rate of degradation of cellulosic biomass by classical glycoside hydrolases. Conclusion Shipworms are wood-boring marine molluscs that can live on a diet of lignocellulose. Bacterial symbionts of shipworms provide many of the enzymes needed for wood digestion. The shipworm symbiont T. turnerae produces one of the few LPMOs yet described from the marine environment, notably adding to the capability of shipworms to digest recalcitrant polysaccharides.

We face a food crisis. Suboptimal diet is the biggest cause of death worldwide, food production the biggest greenhouse gas emitting sector, and by 2050 an extra 2.5 billion people need affordable nutrition. Current farming systems will fail to tackle this crisis, and there is an urgent need to diversify global food production and find effective solutions in currently underexploited food sectors. Shipworms, or shell-less Teredo clams, could prove a highly valuable component of such solutions. Historically viewed as a marine pest, they have unique physiological characteristics which make them an ideal food source, including exceptionally fast growth rates, the ability to feed on waste wood or sustainable microalgae, and a high protein and omega 3 content. Today only a select few traditional cultures in the Philippines consume shipworms, but there is considerable opportunity to develop mechanisms to farm shipworms and provide a sustainable, nutrient rich, affordable food source. This will require significant challenges to be overcome, ranging from fundamental research to industry development to food processing and marketing. Leveraging new innovations in breeding, aquaculture feeds, growth systems, food processing methodologies and consumer engagement can however offer powerful solutions, and could help turn what was once a maritime villain into a nutritional savior.

Here we describe an anatomically divergent wood-boring bivalve belonging to the family Teredinidae. Specimens were collected off the coast of Mabini, Batangas, Philippines, in February 2018, from sunken driftwood at a depth of less than 2 m. A combination of characteristics differentiates these specimens from members of previously named teredinid genera and species. Most notable among these include: an enlarged cephalic hood which extends across the posterior slope of the shell valves and integrates into the posterior adductor muscle; a unique structure, which we term the ‘cephalic collar’, formed by protruding folds of the mantle immediately ventral to the foot and extending past the posterior margin of the valves; a large globular stomach located entirely posterior to the posterior adductor muscle and extending substantially beyond the posterior gape of the valves; an elongate crystalline style and style sac extending from the base of the foot, past the posterior adductor muscle, to the posteriorly located stomach; calcareous pallets distinct from those of described genera; a prominently flared mantle collar which extends midway along the stalk of the pallets; and, separated siphons that bear a pigmented pinstripe pattern with highly elaborate compound papillae on the incurrent siphon aperture. We used Micro-Computed Tomography (Micro-CT) to build a virtual 3D anatomical model of this organism, confirming the spatial arrangement of the structures described above. Phylogenetic analysis of the small (18S) and large (28S) nuclear rRNA gene sequences, place this bivalve within the Teredindae on a branch well differentiated from previously named genera and species. We propose the new genus and species Tamilokus mabinia to accommodate these organisms, raising the total number of genera in this economically and environmentally important family to 17. This study demonstrates the efficacy of Micro-CT for anatomical description of a systematically challenging group of bivalves whose highly derived body plans are differentiated predominantly by soft tissue adaptations rather than features of calcareous hard-parts.

The aim of this study was to select isolated filamentous fungi, naturally occurring in the digestive tract of Neoteredo reynei , with high potential to hydrolyze cellulolytic biomass. The selection of the fungi strains, which produce cellulases, was performed by adding carboxymethylcellulose (CMC), microcrystalline cellulose (MCC) or glucose in the media containing peptone and yeast-extract. In this case, the glucose was used as a reference standard for the growth of the mycelia. The abilities of the fungal strains, to hydrolyze cellulose, on the solid media (MCC or CMC), were evaluated. Two methods were used: the congo-red and the speed of mycelial growth. The measurements of the diameters were performed at 24 h intervals, and the speed of the mycelial growth was calculated after 72 h of cultivation. The molecular and morphological identification of the fungi were applied to the isolated strains. Statistical analysis, including ANOVA and Tukey test, and multivariate analysis were applied as tools to select the strains. Twelve strains were isolated and the results of the identification were 2 strains of Hypocrea lutea , 2 strains of Trichoderma reesei , 2 strains of Aspergillus niger; 2 genera of Aspergillus sp., 2 genera of Trichoderma sp., 1 genus of Fusarium sp. and 1 genus of Gliocadium sp. The discrimination analysis methods such as HCA (Hierarchical Cluster Analysis) and PCA (Principal Component Analysis) indicated three strains with the highest potential to hydrolyze cellulose. In this study, the selection strategy was successful, resulting in the classification of strains from the genera Trichoderma and Hypocrea. This is the first time that this kind of studying was applied to select the potential of the cellulolytic fungal strains, isolated from N. reynei , using the methods of the growth of the mycelial diameter and the statistical discrimination. Unlabelled Image • Filamentous fungi from mollusks presented an evident hydrolytic potential. • Strains with highest potential do not necessarily has the largest mycelial diameter. • Exploratory data analysis allowed a better selection of the strains of interest. [ABSTRACT FROM AUTHOR]

Here we describe an anatomically divergent wood-boring bivalve belonging to the family Teredinidae. Specimens were collected off the coast of Mabini, Batangas, Philippines, in February 2018, from sunken driftwood at a depth of less than 2 m. A combination of characteristics differentiates these specimens from members of previously named teredinid genera and species. Most notable among these include: an enlarged cephalic hood which extends across the posterior slope of the shell valves and integrates into the posterior adductor muscle; a unique structure, which we term the 'cephalic collar', formed by protruding folds of the mantle immediately ventral to the foot and extending past the posterior margin of the valves; a large globular stomach located entirely posterior to the posterior adductor muscle and extending substantially beyond the posterior gape of the valves; an elongate crystalline style and style sac extending from the base of the foot, past the posterior adductor muscle, to the posteriorly located stomach; calcareous pallets distinct from those of described genera; a prominently flared mantle collar which extends midway along the stalk of the pallets; and, separated siphons that bear a pigmented pinstripe pattern with highly elaborate compound papillae on the incurrent siphon aperture. We used Micro-Computed Tomography (Micro-CT) to build a virtual 3D anatomical model of this organism, confirming the spatial arrangement of the structures described above. Phylogenetic analysis of the small (18S) and large (28S) nuclear rRNA gene sequences, place this bivalve within the Teredindae on a branch well differentiated from previously named genera and species. We propose the new genus and species Tamilokus mabinia to accommodate these organisms, raising the total number of genera in this economically and environmentally important family to 17. This study demonstrates the efficacy of Micro-CT for anatomical description of a systematically challenging group of bivalves whose highly derived body plans are differentiated predominantly by soft tissue adaptations rather than features of calcareous hard-parts. [ABSTRACT FROM AUTHOR]

The bioactivity-guided purification of the culture broth of the shipworm endosymbiont Teredinibacter turnerae strain 991H.S.0a.06 yielded a new fatty acid, turneroic acid (1), and two previously described oxylipins (2–3). Turneroic acid (1) is an 18-carbon fatty acid decorated by a hydroxy group and an epoxide ring. Compounds 1–3 inhibited bacterial biofilm formation in Staphylococcus epidermidis, while only 3 showed antimicrobial activity against planktonic S. epidermidis. Comparison of the bioactivity of 1–3 with structurally related compounds indicated the importance of the epoxide moiety for selective and potent biofilm inhibition.

Very little is known about the growth rates of Lyrodus pedicellatus , or their behaviour within English waters, and due to difficulties with morphological identification it is highly likely that its presence has often been confused with Teredo navalis . Over 5 months the growth rate of L. pedicellatus was monitored within a laboratory environment, where tanks were kept consistent with the temperature along the south coast of England. Each month, test panels were X-rayed and the tunnel length and volume was recorded using CAD. During these months, L .pedicellatus achieved an average tunnel length growth rate of 7.14mm/month −1 , furthermore the tunnel volume growth varied across all individuals but L. pedicellatus was able to increase volume growth rate on a month by month basis. Results produced low numbers of juveniles growths, and growth rates appeared slow in comparison to other Teredinids, additionally, it appears that for a large portion of the year, the temperatures along the south coast of England are very close to L. pedicellatus ’ minimum reproductive parameters, thus inhibiting their full reproductive potential. Nonetheless, their life history strategy and presence along the English coastline is worrying for many maritime structures and consequently, L. pedicellatus should be regarded as an invasive species whose abundance and behaviour needs to be closely monitored. [ABSTRACT FROM AUTHOR]

Wooden groin systems on the southwestern Baltic Sea coast are a traditional and important coastal-protection facility, but have been regularly infested and destroyed by the wood-boring bivalve Teredo navalis since the early 1990s. The occurrence of T. navalis was presumed to be limited mainly by the prevailing low salinities. Recently, a possible range expansion of this invasive species to the more eastern parts of the Baltic Sea has been discussed. T. navalis larval settlement was therefore monitored at the distribution boundary of the species in the Baltic Sea over a period of 4 years. At 7 stations along the prevailing salinity gradient on the Mecklenburg-western Pomeranian coast, larval traps were installed at regular time intervals, while at the same time water temperature and salinity were measured continuously every hour. Correlations between measured abiotic parameters and borehole abundance of T. navalis were tested. For the German Baltic Sea coast, no range expansion of T. navalis was confirmed. The salinity and temperatures at the groin systems varied among the study years, and significant correlations between T. navalis borehole abundance and salinity as well as temperature were found. Higher summer temperatures favor the T. navalis borehole abundance on the Mecklenburg-western Pomeranian coast, and may slightly shift the distribution border of this species toward lower salinities.

Archaeological wooden remains are at risk of rapid degradation by the shipworm, Teredo navalis , when exposed to open seawater. An earlier study has shown a difference in the extent of attack based on the state of preservation of the wood. The current study aims to examine in more detail how shipworm attack correlates to the state of preservation, as measured by density, and the amount of residual cellulose, and if it is thereby possible to estimate when attacks will occur based on the level of deterioration. This knowledge would have practical implications for in situ preservation of wooden natural and cultural heritage underwater as it may be able to predict whether a wooden object is in danger of being attacked. The results confirm that there is a significant correlation between the extent of deterioration of the wood and the shipworm attacks. Samples with low density (< 100 kg/m 3 ) and a low cellulose content (≤ 24% weight/dry weight) showed no attacks (rating 0). Attacks (rating 1–2) were first observed when the density of the wood was ≥ 134 kg/m 3 , with concomitant cellulose contents of ≥ 29%. Severe attack (rating 3–4) was observed on samples where the density was ≥ 292 kg/m 3 and cellulose contents of ≥ 48%. [ABSTRACT FROM AUTHOR]

The "wooden-steps" hypothesis [Distel DL, et al. (2000) Nature 403:725-726] proposed that large chemosynthetic mussels found at deep-sea hydrothermal vents descend from much smaller species associated with sunken wood and other organic deposits, and that the endosymbionts of these progenitors made use of hydrogen sulfide from biogenic sources (e.g., decaying wood) rather than from vent fluids. Here, we show that wood has served not only as a stepping stone between habitats but also as a bridge between heterotrophic and chemoautotrophic symbiosis for the giant mud-boring bivalve Kuphus polythalamia. This rare and enigmatic species, which achieves the greatest length of any extant bivalve, is the only described member of the wood-boring bivalve family Teredinidae (shipworms) that burrows in marine sediments rather than wood. We show that K. polythalamia harbors sulfur-oxidizing chemoautotrophic (thioautotrophic) bacteria instead of the cellulolytic symbionts that allow other shipworm species to consume wood as food. The characteristics of its symbionts, its phylogenetic position within Teredinidae, the reduction of its digestive system by comparison with other family members, and the loss of morphological features associated with wood digestion indicate that K. polythalamia is a chemoautotrophic bivalve descended from wood-feeding (xylotrophic) ancestors. This is an example in which a chemoautotrophic endosymbiosis arose by displacement of an ancestral heterotrophic symbiosis and a report of pure culture of a thioautotrophic endosymbiont. [ABSTRACT FROM AUTHOR]

The oceans and seas receive coarse woody debris since the Devonian, but the kinetics of wood degradation remains one of many unanswered questions about the fate of driftwood in the marine environment. A simple gravimetric experiment was carried out at a monitoring station located at the exit of a steep, forested Mediterranean watershed in the Eastern Pyrenees. The objective was to describe and quantify, with standardized logs (in shape, structure and constitution), natural degradation of wood in the sea. Results show that the mass decrease of wood logs over time can be described by a sigmoidal curve. The primary process of wood decay observed at the monitoring station was due to the arrival and installation of wood-boring species that consumed more than half of the total wood mass in six months. Surprisingly, in a region where there is little remaining wood marine infrastructure, “shipworms”, i.e. xylophagous bivalves, are responsible for an important part of this wood decay. This suggests that these communities are maintained probably by a frequent supply of a large quantity of riparian wood entering the marine environment adjacent to the watershed. By exploring this direct link between terrestrial and marine ecosystems, our long term objective is to determine how these supplies of terrestrial organic carbon can sustain wood-based marine communities as it is observed in the Mediterranean Sea. [ABSTRACT FROM AUTHOR]

Marine borers such as the shipworm, Teredo navalis , can cause great destruction to wooden archaeological remains in the marine environment. The focus of this study was to investigate whether shipworm preferentially settle on one orientation of the wood over another, i.e. radial, tangential or transversal and if the resulting tunnels are oriented in a specific direction according to the fibres within the wood. This was investigated using Computed Tomography (CT) scanning and subsequent 3D modelling as a method of both quantifying the severity of attack by shipworm and examining the orientation of the tunnels. Panels of pine, cut in tangential, radial and transversal planes, were placed in the sea at a location where shipworm was known to be abundant. After attack, the panels were weighed, X-rayed, entrance holes counted and 3D CT models created. All results show a difference between the three planes. The specific direction of the single tunnels could be evaluated using the CT models, since the individual tunnels could be isolated, and followed throughout the panel. The results show that the radial plane suffered a more severe attack than either of the two other planes. These results have implications for archaeological interpretation and conservation. For example, the results show that ancient ships built with timbers cut in a radial plane (e.g. Viking Ships or other structural elements cut in radial plane) may be more prone to attack and thus require more protection than those built in tangential or transversal plane should they be raised (difficulties lifting due to fragility) or preserved in situ . [ABSTRACT FROM AUTHOR]

The marine borer, known as shipworm, has long been known for their degradation of wooden constructions in the marine environment. This review presents the results from a variety of experiments conducted at the National Museum of Denmark throughout the past five years dealing with the in situ preservation of maritime archaeological artefacts in light of the threat from shipworm. The aim of the research has been to improve methods and analyses for conducting experiments with shipworm, and to better our understanding of their attack pattern and how to stop an active attack in situ. [ABSTRACT FROM AUTHOR]

The resistance of differently modified wood to the common shipworm, Teredo navalis , and the wood boring crustacean, Limnoria quadripunctata , was assessed in a field trial and by means of a short term laboratory assay, respectively. Scots pine ( Pinus sylvestris ) sapwood was treated with TEOS (tetra-ethoxy-ortho-silane) and different thermosetting resins, namely phenol formaldehyde (PF) and methylated melamine formaldehyde (MMF). Additionally, acetylated and untreated Radiata pine ( Pinus radiata ) was included. In the field trial according to EN 275 in the Baltic Sea over a period of six years the specimens were exclusively attacked by T . navalis . For the laboratory assay, matchstick-sized samples cut from spare panels prepared for the field trial were subjected to individuals of L . quadripunctata ; faecal pellet production served as a measure of feeding rate. Treatments that prevented shipworm attack in the field also reduced feeding of L . quadripunctata in the laboratory assay: efficacy of resin treatments was enhanced by parameters that increase the amount of resin in the cell wall (i.e. high WPG and dry curing conditions); acetylation resulted in high resistance; and TEOS treatment was not effective. The results suggest that modification on cell wall level is required to impart marine borer resistance. [ABSTRACT FROM AUTHOR]

The activity of marine wood-borers causes great destruction in maritime wooden structures. Therefore, the aim of this study was to evaluate the hazard posed by marine wood-borers in fifteen European sites, to assist authorities and researchers concerned with the protection of wood in the sea. In northern Europe, Teredo navalis is the species that poses the highest borer hazard while in the Atlantic coast of southern Europe Lyrodus pedicellatus is the most destructive species, with the exception of two sites in Portugal. In these sites, Limnoria tripunctata was more destructive than L. pedicellatus . In the Mediterranean both T. navalis and L. pedicellatus pose a very high borer hazard to wooden structures. Salinity and temperature emerged as the environmental conditions that best explain the occurrence and abundance of wood boring species in the sites surveyed. Three of the species highlighted in this study are warm water species. Therefore their activity might increase in the future, due to global warming. Considering that wood is still a very valuable material for construction, its use for maritime construction should be favoured. Thus research to improve the durability of wooden materials in the marine environment is of paramount importance. [ABSTRACT FROM AUTHOR]

Teredinids, commonly referred to as shipworms, are wood-boring bivalves estimated to cause over one billion dollars' worth of damage to submerged wooden structures per annum. This paper reports the detection and establishment of the Caribbean shipworm Teredothyra dominicensis (Bivalvia, Teredinidae) in the eastern Mediterranean Sea. Identification was confirmed using an integrative taxonomical approach combining morphology, morphometry and molecular markers (COI-5P and 18S), thus improving both the taxonomic resolution and tractability of this invasive species. Sequence comparisons between indigenous Caribbean and Mediterranean specimens were at least 99 % identical. Wooden panels placed at the site of discovery were infested exclusively by T. dominicensis with specimens of varying size and age, indicating multiple settlement events and the presence of breeding populations in the region. Anatomical and behavioural observations confirm the species as a broadcast spawner with larvae undergoing planktotrophic development, thus distribution range is potentially extensive. Of the possible introduction vectors, transport via ballast water is proposed as the most likely. The establishment of breeding populations of a tropical teredinid in the Mediterranean is of considerable concern as tropical species are particularly destructive and degrade wood more rapidly than the species currently found in the region. This threat is likely to increase in severity due to global warming, as increases in temperature and salinity may lead to an increase in the distribution range, development rate and boring activity of teredinids. [ABSTRACT FROM AUTHOR]

Teredinibacter turnerae is a cultivable intracellular endosymbiont of xylotrophic (wood-feeding) bivalves of the Family Teredinidae (shipworms). Although T. turnerae has been isolated from many shipworm taxa collected in many locations, no systematic effort has been made to explore genetic diversity within this symbiont species across the taxonomic and geographical range of its hosts. The mode of symbiont transmission is unknown. Here, we examine sequence diversity in fragments of six genes (16S rRNA, gyrB, sseA, recA, rpoB and celAB) among 25 isolates of T. turnerae cultured from 13 shipworm species collected in 15 locations in the Atlantic, Pacific and Indian Oceans. While 16S rRNA sequences are nearly invariant between all examined isolates (maximum pairwise difference <0.26%), variation between examined protein-coding loci is greater (mean pairwise difference 2.2-5.9%). Phylogenetic analyses based on each protein-coding locus differentiate the 25 isolates into two distinct and well-supported clades. With five exceptions, clade assignments for each isolate were supported by analysis of alleles of each of the five protein-coding loci. These exceptions include (i) putative recombinant alleles of the celAB and gyrB loci in two isolates (PMS-535T.S.1b.3 and T8510), suggesting homologous recombination between members of the two clades; and (ii) evidence for a putative lateral gene transfer event affecting a second locus (recA) in three isolates (T8412, T8503 and T8513). These results demonstrate that T. turnerae isolates do not represent a homogeneous global population. Instead, they indicate the emergence of two lineages that, although distinct, likely experience some level of genetic exchange with each other and with other bacterial species. [ABSTRACT FROM AUTHOR]

Brazilian mangroves have ecological and economic importance, with molluscs, crustaceans and polychaetes being diverse and common faunal groups. The present study characterizes the macrofauna associated with logs from two mangrove forests in Pará State, northern Brazil, sampled in September, January and April, between 2008 and 2010, at three different distances from a tidal channel (2, 10, 20 m). In each forest, five logs (diameter/length: 10/40 cm) were randomly selected at each distance, totalling 15 logs per sampling date. The macrofauna was removed, counted and identified. Three-way analysis of variance was used to compare mean numbers of individuals, numbers of taxa and Berger–Parker dominance per log, between forests and among sampling dates and distances from the tidal channel. Non-metric multidimensional scaling and permutational multivariate analyses of variance were used to investigate macrofaunal structure in relation to the three factors. A total of 5437 individuals from both estuarine and terrestrial faunas was found in both forests, with 85 taxa distributed among Mollusca, Annelida, Arthropoda and Nemertea. Abundance increased from September through January to April in both mangrove forests. The most dominant species was Neoteredo reynei, representing 48% of total abundance. No significant difference in any variable was found among the two forests and between the three distances. Logs may represent a stable microhabitat for the macrofauna, with little variation in humidity, salinity or temperature, despite different distances from the tidal channel. However, macrofaunal structure varied significantly between forests and among sampling dates, probably due to seasonal differences in precipitation and salinity between both locations. [ABSTRACT FROM PUBLISHER]

Abstract: The great shipworm Teredo navalis is a bivalve of the Teredinidae family known for its efficient ability at degrading wood and feeding on sugar molecules constituting its building blocks. The aim of this study was to identify new endogenous genes encoding cellulose-degrading enzymes from the shipworm. We suspect those genes to play an important role in the efficient biomass degradation of T. navalis. We constructed an expressed sequence tag (EST) database of 3‘end cDNAs prepared by reverse transcription of mRNAs prepared from the shipworm whole body. A GS FLX 454 pyrosequencing system was used to sequence the transcriptome. A total of 12,879 contigs and 80,891 singlets were obtained and probed using blast2go. In this short paper we present the preliminary findings of our study. [Copyright &y& Elsevier]

Abstract: The effects of four climate change scenarios for the Netherlands on the distribution of the shipworm upstream of the Rhine–Meuse estuary are described. Global warming will cause dry and warmer summers and decreased river discharges. This will extend the salinity gradient upstream in summer and fall and may lead to attacks on wooden structures by the shipworm. Scenarios including one or two degree temperature increases by 2050 compared to 1990 with a weak change in the air circulation over Europe will lead to an increased chance of shipworm damage upstream from once in 36years to once in 27 or 22years, respectively; however, under a strong change in air circulation, the chance of shipworm damage increases to once in 6 or 3years, respectively. The upstream expansion of the distribution of the shipworm will also be manifested in other northwest European estuaries and will be even stronger in southern Europe. [Copyright &y& Elsevier]

Abstract: During the period 2004–2008 the distribution, settlement, and growth of first-year shipworms (Teredo navalis L., 1758) was studied by exposing fir and oak panels in the Port of Rotterdam area, which is situated in the Rhine-Meuse estuary in the Netherlands and covers the complete salinity gradient. Shipworms were found yearly in the western large polyhaline harbours. On only a few occasions were they were found in harbours that showed large seasonal and daily fluctuations in salinity. In 2006 the shipworm was found in fir panels 20km upstream from the polyhaline harbours, demonstrating their ability to travel with the tidal currents over considerable distances and to settle once the abiotic conditions become favourable. Although the water temperatures allowed them to breed from April until November, infestations were not found before September, and from the size of the animals in the panels it was concluded that in the Port of Rotterdam area they spawned from August until the end of November. The settlement height was negatively correlated with the distance of the panels to the sea floor. In the first season after settlement they showed a substantial growth rate of 0.18cmday−1. The longest shipworm found measured 36.8cm after 4–5 months of growth after settlement. Infestations and growth were lower in oak than in fir wood. In 2006 the maximum consumption of wood by individuals settled in the same year in panels at the bottom accounted for 12.4%. Shell size and body length of the animal after the first season of growth showed a significant positive logarithmic relation. In both 2006 and 2007 a similar relation between the average boring tube diameter and the length of the animals was found. Lower river discharges leading to salinisation of the eastern part of the Port of Rotterdam area create conditions favourable for the shipworm, with serious consequences for the piles upon which the quays are built. [Copyright &y& Elsevier]

Cells from a marine bacterium, Teredinobacter turnirae cells were immobilized in calcium alginate beads and used for alkaline protease production. The maximum protease activity was obtained at 3% (w/v) sodium alginate and 3% CaCl2 concentrations with a 1/2 cell/alginate ratio, i.e. 2400 U/ml. There was no significant difference in the maximum protease activity between three bead sizes used. A drastic fall in protease production was observed when the beads were treated with glutaraldehyde. The beads were used for eight successive fermentation batches each lasting 72 h. It was also observed that there was a ∼3.5-fold increase in volumetric productivity of protease after the fourth cycle. [Copyright &y& Elsevier]

Shipworms (Bivalvia: Teredinidae) are considered one of the main agents of wood bioerosion in the marine environment. They dig tunnels inside the wood they feed on, causing its progressive weakening. X-rays are a widely used non-destructive technique to assess wood biodeterioration (e.g. EN 275). However, an X-ray is a two-dimensional projection, with the possibility that some of the objects overlap and obfuscate each other. The higher the density of the shipworms, the more difficult is to count and measure the single tunnel. The aim of this work was to find a straight-forward method for calculating the volume of shipworm tunnels based on the size of shipworm shells, which are always clearly identifiable on the X-rays. Some wood test panels attacked by shipworms were analysed, with two distinct geometric methods being applied to estimate the tunnels volume based on radiographs. An allometric model was then introduced linking the volume to the shell diameter, which allows an easy estimation of the actual bioeroded volume from conventional two-dimensional radiographs. This technique allows to evaluate the bioerosion after the first growing season, shortening the exposure time and reducing costs. The model can be applied even when the tunnels are difficult to distinguish from each other, i.e. overlapped, folded or covering the whole surface of the radiograph. • Wood bioerosion caused by shipworms is so far estimated from radiographs analysis. • Complex shape and superimposition of tunnels may cause severe estimation errors. • An allometric model is proposed to estimate the bioeroded volume from shell size. • The model fits better for the first growth phases, legitimizing a shorter test times. [ABSTRACT FROM AUTHOR]

The bioactivity-guided purification of the culture broth of the shipworm endosymbiont Teredinibacter turnerae strain 991H.S.0a.06 yielded a new fatty acid, turneroic acid (1), and two previously described oxylipins (2–3). Turneroic acid (1) is an 18-carbon fatty acid decorated by a hydroxy group and an epoxide ring. Compounds 1–3 inhibited bacterial biofilm formation in Staphylococcus epidermidis, while only 3 showed antimicrobial activity against planktonic S. epidermidis. Comparison of the bioactivity of 1–3 with structurally related compounds indicated the importance of the epoxide moiety for selective and potent biofilm inhibition. [ABSTRACT FROM AUTHOR]

Abstract: Stable isotope analysis of soft bodies of the shipworm Teredo navalis demonstrated that this species is mainly feeding on seston by filter feeding in contrast to wood consumption. T. navalis showed similar stable isotope values (δ13C, δ15N) as Mytilus edulis and Crassostrea gigas, which species were attached to the wood instead of boring into. [Copyright &y& Elsevier]