Peer Reviewed Publications

Drug Discovery

Synthesis and bioactivity of nobilamide B

M. P. V. Jacinto, M. S. Flores, Z. Lin, G. P. Concepcion, E. W. Schmidt, S. Faulkner, and A. J. L. Villaraza

An alternative and facile solution/solid-phase approach is reported for the total synthesis of neuroactive peptide, nobilamide B. Z-Dhb was formed in solution via EDC/CuCl induced elimination. The solid-phase synthesis employed HBTU/Oxyma PureTM coupling using Barlos resin. Synthetic nobilamide B was also found to be neuroactive in primary cultures of dorsal root ganglion (DRG) neurons. Article

Drug Discovery

Griseorhodins D-F, Neuroactive Intermediates and End Products of Post-PKS Tailoring Modification in Griseorhodin Biosynthesis

Lin Z, Zachariah MM, Marett L, Hughen RW, Teichert RW, Concepcion GP, Haygood MG, Olivera BM, Light AR, Schmidt EW

The griseorhodins belong to a family of extensively modified aromatic polyketides that exhibit activities such as inhibition of HIV reverse transcriptase and human telomerase. The vast structural diversity of this group of polyketides is largely introduced by enzymatic oxidations, which can significantly influence the bioactivity profile. Four new compounds, griseorhodins D-F, were isolated from a griseorhodin producer, Streptomyces sp. CN48+, based upon their enhancement of calcium uptake in a mouse dorsal root ganglion primary cell culture assay... Article

Drug Discovery

Boronated tartrolon antibiotic produced by symbiotic cellulose-degrading bacteria in shipworm gills

Sherif I. Elshahawi, Amaro E. Trindade-Silva, Amro Hanora, Andrew W. Han, Malem S. Flores, Vinicius Vizzoni, Carlos G. Schrago, Carlos A. Soares, Gisela P. Concepcion, Dan L. Distel, Eric W. Schmidt, and Margo G. Haygood

Shipworms are marine wood-boring bivalve mollusks (family Teredinidae) that harbor a community of closely related Gammaproteobacteria as intracellular endosymbionts in their gills. These symbionts have been proposed to assist the shipworm host in cellulose digestion and have been shown to play a role in nitrogen fixation. The genome of one strain of Teredinibacter turnerae, the first shipworm symbiont to be cultivated, was sequenced, revealing potential as a rich source of polyketides and nonribosomal peptides. Article

Drug Discovery

Nobilamides A-H, long-acting transient receptor potential vanilloid-1 (TRPV1) antagonists from mollusk-associated bacteria

Lin Z, Reilly CA, Antemano R, Hughen RW, Marett L, Concepcion GP, Haygood MG, Olivera BM, Light A, Schmidt EW.

New compounds nobilamides A-H and related known compounds A-3302-A and A-3302-B were isolated based upon their suppression of capsaicin-induced calcium uptake in a mouse dorsal root ganglion primary cell culture assay. Two of these compounds, nobilamide B and A-3302-A, were shown to be long-acting antagonists of mouse and human TRPV1 channels, abolishing activity for >1 h after removal of drug presumably via a covalent attachment. Other derivatives also inhibited the TRPV1 channel, albeit with low potency, affording a structure-activity profile to support the proposed mechanism of action... Article

Biodiversity Inventory and Biodiversity Conservation

Microbial Distribution and Abundance in the Digestive System of Five Shipworm Species (Bivalvia: Teredinidae)

Meghan A. Betcher, Jennifer M. Fung, Andrew W. Han, Roberta O’Connor, Romell Seronay, Gisela P. Concepcion, Daniel L. Distel, Margo G. Haygood

Marine bivalves of the family Teredinidae (shipworms) are voracious consumers of wood in marine environments. In several shipworm species, dense communities of intracellular bacterial endosymbionts have been observed within specialized cells (bacteriocytes) of the gills (ctenidia). These bacteria are proposed to contribute to digestion of wood by the host. While the microbes of shipworm gills have been studied extensively in several species, the abundance and distribution of microbes in the digestive system have not been adequately addressed... Article

Drug Discovery

Totopotensamides, polyketide-cyclic peptide hybrids from a mollusk-associated bacterium Streptomyces sp.

Lin Z, Flores M, Forteza I, Henriksen NM, Concepcion GP, Rosenberg G, Haygood MG, Olivera BM, Light AR, Cheatham TE 3rd, Schmidt EW

Two new compounds, the peptide-polyketide glycoside totopotensamide A (1) and its aglycone totopotensamide B (2), were isolated from a Streptomyces sp. cultivated from the gastropod mollusk Lienardia totopotens collected in the Philippines. The compounds contain a previously undescribed polyketide component, a novel 2,3-diaminobutyric acid-containing macrolactam, and a new amino acid, 4-chloro-5,7-dihydroxy-6-methylphenylglycine. The application of Marfey's method to phenylglycine derivatives was explored using quantum mechanical calculations and NMR. Article

Biodiversity Inventory and Biodiversity Conservation

The complete genome of Teredinibacter turnerae T7901: an intracellular endosymbiont of marine wood-boring bivalves (family Teredinidae)

Joyce C. Yang, A. Scott Durkin, Ramana Madupu, Nathan A. Ekborg, Bernard Henrissat, Sandra Schwartz, Joseph C. Mougous, Chandra S. Pedamallu, Lauren Fields, Amaro E. Trindade-Silva, Carlos A. G. Soares, Sherif Elshahawi, Amro Hanora, Margo G. Haygood, Janos Posfai, Jack Benner, Casey Swaim, John Nove, Brian Anton, Kshitiz Chaudhary, Jeremy Foster, Alex Holman, Sanjay Kumar, Philip A Lessard, Yvette A. Luyten, Barton Slatko, Nicole Wood, Bo Wu, John Zehr, Max Teplitski, Naomi Ward, Jonathan A. Eisen, Jonathan H. Badger, and Daniel L. Distel

Here we report the complete genome sequence of Teredinibacter turnerae T7901. T. turnerae is a marine gamma proteobacterium that occurs as an intracellular endosymbiont in the gills of wood-boring marine bivalves of the family Teredinidae (shipworms). This species is the sole cultivated member of an endosymbiotic consortium thought to provide the host with enzymes, including cellulases and nitrogenase, critical for digestion of wood and supplementation of the host's nitrogen-deficient diet... Article

Biodiversity Inventory and Biodiversity Conservation

A New Species of Lienardia (Gastropoda: Conoidea) from the Philippines and the Spratly Islands

Gary Rosenberg and Peter Stahlschmidt (Academy of Natural Sciences, 1900 Benjamin Franklin Parkway, Philadelphia, PAand Institute for Environmental Sciences, University of Koblenz-Landau,Germany)

A new species of Lienardia (Conoidea: Clathurellidae) is described from the Philippines and Spratly Islands and compared to L. giliberti Souverbie, 1874, with which it has been confused. The species is routinely found in lumun-lumun nets in the southern Philippines, particularly in the Panglao area, in depths of 50 and HO m. Correlations between radular morphology and shell coloration support maintaining Lienardia and Clathurella as distinct genera. Article

Biodiversity Inventory and Biodiversity Conservation

Molecular phylogeny of Pholadoidea Lamarck, 1809 supports a single origin for xylotrophy (wood feeding) and xylotrophic bacterial endosymbiosis in Bivalvia

Distel DL, Amin M, Burgoyne A, Linton E, Mamangkey G, Morrill W, Nove J, Wood N, Yang J.

The ability to consume wood as food (xylotrophy) is unusual among animals. In terrestrial environments, termites and other xylotrophic insects are the principle wood consumers while in marine environments wood-boring bivalves fulfill this role. However, the evolutionary origin of wood feeding in bivalves has remained largely unexplored. Here we provide data indicating that xylotrophy has arisen just once in Bivalvia in a single wood-feeding bivalve lineage that subsequently diversified into distinct shallow- and deep-water branches, both of which have been broadly successful in colonizing the world's oceans. Article

Drug Discovery

Pulicatins A-E, neuroactive thiazoline metabolites from cone snail-associated bacteria

Lin Z, Antemano RR, Hughen RW, Tianero MD, Peraud O, Haygood MG, Concepcion GP, Olivera BM, Light A, Schmidt EW

The cone snail Conus pulicarius from the Philippines provides a specific habitat for actinomycetes and other bacteria. A phenotypic screen using primary cultures of mouse dorsal root ganglion neurons revealed that one C. pulicarius associate, Streptomyces sp. CP32, produces a series of natural products that enhance or diminish whole-cell Ca(2+) flux. These compounds include known thiazoline compounds and a series of new derivatives, pulicatins A-E (6-10)... Article

Biodiversity Inventory and Biodiversity Conservation

The microniche approach to discovering diverse actinomycete bacteria in cone snails

Olivier Peraud, Jason S. Biggs, Ronald W. Hughen, Alan R. Light, Gisela P. Concepcion, Baldomero M. Olivera and Eric W. Schmidt

Numerous studies have shown that actinomycetes can be symbionts in diverse organisms, including both plants and animals. Some actinomycetes benefit their host by producing small molecule secondary metabolites; the resulting symbioses are often developmentally complex. We examined the actinomycetes associated with three cone snails, venomous tropical marine gastropods which have been extensively examined because of their production of peptide-based neurological toxins but for which no microbiological studies have been reported... Article

Biodiversity Inventory and Biodiversity Conservation

One, Four or 100 Genera? Classification of the Cone Snails

Puillandre, N., Duda, T.F., Jr., Meyer, C.P., Olivera, B.M., and Bouchet, P.

Article

Drug Discovery

Constellation Pharmacology: A new paradigm for drug discovery

Teichert, R.W., Schmidt, E.W., and Olivera, B.M.

Article

Biodiversity Inventory and Biodiversity Conservation

Seven new species of Thala (Gastropoda: Costellariidae) from the Indo-Pacific

BC Rosenberg, G. and R. Salisbury

Seven new species of Thala are described: T. abelai and T. merrilli (type locality Guam, Mariana Islands), T. evelynae and T. suduirauti (Philippines), T. kilburni and T. pallida (Bassas da India Reef, Mozambique Channel) and T. ruggeriae (Tanzania) and their geographic ranges established. Lectotypes are selected for T. exilis (Reeve, 1845), T. roseata (A. Adams, 1855), T. fusus (Souverbie, 1876), and T. ogasawarana Pilsbry, 1904, and T. fusus is synonymized with T. mirifica (Reeve, 1845)... Article

Drug Discovery

Chapter 6: The Molecular Diversity of Conoidean Venom Peptides and their Targets: From Basic Research to Therapeutic Applications. In: Venoms to Drugs

Teichert, R.W., Olivera, B.M., McIntosh, J.M., Bulaj, G., Horvath, M.P

Article

Biodiversity Inventory and Biodiversity Conservation

Biodiversity of Cone Snails and other Venomous Marine Gastropods: Evolutionary Success Through Neuropharmacology

Olivera, B.M., Showers-Corneli, P., Watkins, M., Fedosov, A.

Venomous marine snails (superfamily Conoidea) are a remarkably biodiverse marine invertebrate lineage (featuring more than 10,000 species). Conoideans use complex venoms (up to 100 different components for each species) to capture prey and for other biotic interactions. Molecular phylogeny and venom peptide characterization provide an unusual multidisciplinary view of conoidean biodiversity at several taxonomic levels. Venom peptides diverge between species at an unprecedented rate through hypermutation within gene families... Article

Biodiversity Inventory and Biodiversity Conservation

Molecular Phylogeny and Evolution of the Cone Snails (Gastropoda, Conoidea)

Puillandre N., Bouchet P., Duda, T. F., Kauferstein, S., Kohn, A. J., Olivera, B.M., Watkins, M., Meyer C.

We present a large-scale molecular phylogeny that includes 320 of the 761 recognized valid species of the cone snails (Conus), one of the most diverse groups of marine molluscs, based on three mitochondrial genes (COI, 16S rDNA and 12S rDNA). This is the first phylogeny of the taxon to employ concatenated sequences of several genes, and it includes more than twice as many species as the last published molecular phylogeny of the entire group nearly a decade ago... Article

Drug Discovery

Structure and activity of lobophorins from a turrid mollusk-associated Streptomyces sp.

Lin, Z.; Koch, M.; Pond, C.D.; Mabeza, G.; Seronay, R.A.; Concepcion, G.P.; Barrows, L.R.; Olivera, B.M.; Schmidt, E.W.

A novel lumun-lumun sampling methodology was used to obtain a large diversity of micromollusks, including the new species Lienardia totopotens. In turn, from L. totopotens we cultivated a Streptomyces sp. strain that contained new and known spirotetronate polyketides, lobophorins (1–5). The structures were elucidated using spectroscopy, and the compounds were evaluated for cytotoxicity to human cells and activity against Mycobacterium tuberculosis, Bacillus subtilis, Pseudomonas aeruginosa and Burkholderia cepacia... Article

Drug Discovery

Neuroactive diol and acyloin metabolites from cone snail-associated bacteria

Lin, Z.; Marett, L.; Hughen, R.W.; Flores, M.; Forteza, M.; Ammon, M.A.; Concepcion, G.P.; Espino, S.; Olivera, B.M.; Rosenberg, G.; Haygood, M.G.; Light, A.R.; Schmidt, E.W.

The bacterium Gordonia sp. 647W.R.1a.05 was cultivated from the venom duct of the cone snail, Conus circumcisus. The Gordonia sp. organic extract modulated the action potential of mouse dorsal root ganglion neurons. Assay-guided fractionation led to the identification of the new compound circumcin A (1) and 11 known analogs (2-12). Two of these compounds, kurasoin B (7) and soraphinol A (8), were active in a human norepinephrine transporter assay with Ki values of 2575 and 867 nM, respectively... Article

Drug Discovery

Snail Peptides. In Handbook of Biologically Active Peptides: Venom Peptides

DD Olivera BM, Imperial J, Concepcion GP

Peptides play a crucial role in many physiological processes including actions as neurotransmitters, hormones, and antibiotics. Research has shown their importance in such fields as neuroscience, immunology, pharmacology, and cell biology. The Handbook of Biologically Active Peptides presents, for the first time, this tremendous body of knowledge in the field of biologically active peptides in one single reference... Article

Drug Discovery

Turnerbactin, a novel triscatecholate siderophore from the shipworm endosymbiont Teredinibacter turnerae T7901

Han, A.W., M. Sandy, B. Fishman, A.E. Trindade-Silva, C.A.G. Soares, D.L. Distel, A. Butler, M.G. Haygood

Shipworms are marine bivalve mollusks (Family Teredinidae) that use wood for shelter and food. They harbor a group of closely related, yet phylogenetically distinct, bacterial endosymbionts in bacteriocytes located in the gills. This endosymbiotic community is believed to support the host's nutrition in multiple ways, through the production of cellulolytic enzymes and the fixation of nitrogen. The genome of the shipworm endosymbiont Teredinibacter turnerae T7901 was recently sequenced and in addition to the potential for cellulolytic enzymes and diazotrophy, the genome also revealed a rich potential for secondary metabolites... Article

Biodiversity Inventory and Biodiversity Conservation

Adaptive radiation of venomous marine snail lineages and the accelerated evolution of venom peptide genes

Olivera, B.M. M. Watkins, P. Bandyopadhyay, J. S. Imperial, E. P. Heimer de la Cotera, M. B Aguilar, E. López Vera, G. P. Concepcion, and A. Lluisma

An impressive biodiversity (>10,000 species) of marine snails (suborder Toxoglossa or superfamily Conoidea) have complex venoms, containing ca. 100 biologically active, disulfide-rich peptides. In the genus Conus, the most intensively investigated toxoglossan lineage (~500 species), a small set of venom gene superfamilies undergo rapid sequence hyperdiversification within their mature toxin regions... Article

Drug Discovery

A Bacterial Source for Mollusk Pyrone Polyketides

DD Lin, Z., J. P. Torres, M. A. Ammon, L. Marett, R. W. Teichert, C. A. Reilly, J. C. Kwan, R. W. Hughen, M. Flores, M. D.Tianero, O. Peraud, J. E. Cox, A. R. Light, A. J. L. Villaraza, M. G. Haygood, G. P. Concepcion, B. M. Olivera, and E. W. Schmidt

In the oceans, toxic secondary metabolites often protect otherwise poorly defended, soft-bodied invertebrates such as shell-less mollusks from predation. The origins of these metabolites are largely unknown, but many of them are thought to be made by symbiotic bacteria. In contrast, mollusks with thick shells and toxic venoms are thought to lack these secondary metabolites due to reduced defensive needs. Here, we show that heavily defended cone snails also occasionally contain abundant secondary metabolites, γ-pyrones known as nocapyrones, and that these pyrones are synthesized by symbiotic bacteria... Article

Drug Discovery

Small molecules in the cone snail arsenal

Neves, J.L.B., Lin, Z., Imperial, J.S., Antunes, A., Vasconcelos, V., Olivera, B.M., Schmidt, E.W

Article

Drug Discovery

High conopeptide diversity in Conus tribblei revealed through analysis of venom duct transcriptome using two high-throughput sequencing platforms

Barghi N, Concepcion GP, Olivera BM, Lluisma AO

The venom of each species of Conus contains different kinds of pharmacologically active peptides which are mostly unique to that species. Collectively, the ~500-700 species of Conus produce a large number of these peptides, perhaps exceeding 140,000 different types in total. To date, however, only a small fraction of this diversity has been characterized via transcriptome sequencing. In addition, the sampling of this chemical diversity has not been uniform across the different lineages in the genus. In this study, we used high-throughput transcriptome sequencing approach to further investigate the diversity of Conus venom peptides. We chose a species, Conus tribblei, as a representative of a poorly studied clade of Conus. Using the Roche 454 and Illumina platforms, we discovered 136 unique and novel putative conopeptides belonging to 30 known gene superfamilies and 6 new conopeptide groups, the greatest diversity so far observed from a transcriptome. Most of the identified peptides exhibited divergence from the known conopeptides, and some contained cysteine frameworks observed for the first time in cone snails. In addition, several enzymes involved in posttranslational modification of conopeptides and also some proteins involved in efficient delivery of the conopeptides to prey were identified as well. Interestingly, a number of conopeptides highly similar to the conopeptides identified in a phylogenetically distant species, the generalist feeder Conus californicus, were observed. The high diversity of conopeptides and the presence of conopeptides similar to those in C. californicus suggest that C. tribblei may have a broad range of prey preferences. Article

Drug Discovery

Comparison of the Venom Peptides and Their Expression in Closely Related Conus Species: Insights into Adaptive Post- speciation Evolution of Conus Exogenomes

Barghi N, Concepcion GP, Olivera BM, Lluisma AO

Genes that encode products with exogenous targets, which comprise an organism's ‘exogenome’, typically exhibit high rates of evolution. The genes encoding the venom peptides (conotoxins or conopeptides) in Conus sensu lato exemplify this class of genes. Their rapid diversification has been established and is believed to be linked to the high speciation rate in this genus. However, the molecular mechanisms that underlie venom peptide diversification and ultimately emergence of new species remains poorly understood. In this study, the sequences and expression levels of conotoxins from several specimens of two closely related worm-hunting species, Conus tribblei and Conus lenavati, were compared via transcriptome analysis. Majority of the identified putative conopeptides were novel, and their diversity, even in each specimen, was remarkably high suggesting a wide range of prey targets for these species. Comparison of the inter-specific expression patterns of conopeptides at the superfamily level resulted in the discovery of both conserved as well as species-specific expression patterns, indicating divergence in the regulatory network affecting conotoxin gene expression. Comparison of the transcriptomes of the individual snails revealed that each specimen produces a distinct set of highly expressed conopeptides, reflecting the capability of individual snails to fine-tune the composition of their venoms. These observations reflect the role of sequence divergence and divergence in the control of expression for specific conopeptides in the evolution of the exogenome and hence venom composition in Conus. Article

Drug Discovery

Oxazinin A, a pseudodimeric natural product of mixed biosynthetic origin from a filamentous fungus

Lin Z, Koch M, Abdel Aziz MH, Galindo-Murillo R, Tianero MD, Cheatham TE, Barrows LR, Reilly CA, Schmidt EW

A racemic, prenylated polyketide dimer, oxazinin A (1), was isolated from a novel filamentous fungus in the class Eurotiomycetes, and its structure was elucidated spectroscopically. The pentacyclic structure of oxazinin A (1) is a unique combination of benzoxazine, isoquinoline, and a pyran ring. Oxazinin A (1) exhibited antimycobacterial activity and modestly antagonized transient receptor potential (TRP) channels. Article

Biodiversity Inventory and Biodiversity Conservation

A new species of Casmaria H. Adams & A. Adams, 1853 (Gastropoda, Cassidae) from the Philippines identified by molecular data

Fedosov, A., B M Olivera, M Watkins, and V Barkalova

The genus Casmaria H. Adams & A. Adams, 1853 (family Cassidae) is widespread in the tropical Indo-Pacific and has been documented from some Atlantic localities as well. Two Casmaria species, C. erinaceus (Linnaeus, 1758) and C. ponderosa (Gmelin, 1791), are common in Indo-Pacific shallow-water sandy bottom communities and are characterized by high morphological variability; both species encompass multiple, often sympatric forms of uncertain status. In the present study we carry out a phylogenetic analysis of some Philippine Casmaria morphs and demonstrate that one of the distinctive morphs earlier assigned to Casmaria ponderosa is in fact a different species, which we describe as Casmaria boblehmani sp. nov. The smooth form of Casmaria ponderosa, C. ponderosa ponderosa, and the solid nodulose form, widely called “form nodulosa” despite being strikingly different in shell morphology, are shown to be conspecific. Studied specimens of these two morphs even from different localities share the same haplotype of the CO1 gene. In light of these new data on the morphological variability of Casmaria species, we discuss criteria of species delimitation in the genus Casmaria and possible affinities of Casmaria boblehmani sp. nov. within the genus. Article

Drug Discovery

A family of excitatory peptide toxins from venomous crassispirine snails: using Constellation Pharmacology to assess bioactivity

Imperial JS, Cabang AB, Song J, Raghuraman S, Gajewiak J, Watkins M, Showers-Corneli P, Fedosov A, Concepcion GP, Terlau H, Teichert RW, Olivera BM

The toxinology of the crassispirine snails, a major group of venomous marine gastropods within the superfamily Conoidea, is largely unknown. Here we define the first venom peptide superfamily, the P-like crassipeptides, and show that the organization of their gene sequences is similar to conotoxin precursors. We provide evidence that one peptide family within the P-like crassipeptide superfamily includes potassium-channel (K-channel) blockers, the κP-crassipeptides. Three of these peptides were chemically synthesized (cce9a, cce9b and iqi9a). Using conventional electrophysiology, cce9b was shown to be an antagonist of both a human Kv1.1 channel isoform (Shaker subfamily of voltage-gated K channels) and a Drosophila K-channel isoform. We assessed the bioactivity of these peptides in native mammalian dorsal root ganglion neurons in culture. We demonstrate that two of these crassipeptides, cce9a and cce9b, elicited an excitatory phenotype in a subset of small-diameter capsaicin-sensitive mouse DRG neurons that were also affected by κJ-conotoxin PlXIVA (pl14a), a blocker of Kv1.6 channels. Given the vast complexity of heteromeric K-channel isoforms, this study demonstrates that the crassispirine venoms are a potentially rich source for discovering novel peptides that can help to identify and characterize the diversity of K-channel subtypes expressed in native neurons and other cell types. Article

Biodiversity Inventory and Biodiversity Conservation

Gill bacteria enable a novel digestive strategy in a wood-feeding mollusk

R.M. O'Connor, J.M. Fung, K.H. Sharp, J. Benner, C. McClung, S. Cushing, E. Lamkin, A. Fomenkov, B. Henrissat, Y. Londer, M. B. Scholz, J. Posfai, S. Malfatti, S.G. Tringe, T. Woyke, R.R. Malmstrom, D. Coleman-Derr, M.A. Altamia, S. Dedrick, S. T. Kaluziak, M.G. Haygood and D.L. Distel

Article