Analogs of α-conotoxin PnIC selectively inhibit α7β2- over α7-only subtype nicotinic acetylcholine receptors via a novel allosteric mechanism

This study was undertaken to identify and characterize the first ligands capable of selectively identifying nicotinic acetylcholine receptors containing α7 and β2 subunits (α7β2-nAChR subtype). Basal forebrain cholinergic neurons express α7β2-nAChR. Here, they appear to mediate neuronal dysfunction induced by the elevated levels of oligomeric amyloid-β associated with early Alzheimer's disease. Additional work indicates that α7β2-nAChR are expressed across several further critically important cholinergic and GABAergic neuronal circuits within the central nervous system. Further studies, however, are significantly hindered by the inability of currently available ligands to distinguish heteromeric α7β2-nAChR from the closely related and more widespread homomeric α7-only-nAChR subtype. Functional screening using two-electrode voltage-clamp electrophysiology identified a family of α7β2-nAChR-selective analogs of α-conotoxin PnIC (α-CtxPnIC). A combined electrophysiology, functional kinetics, site-directed mutagenesis, and molecular dynamics approach was used to further characterize the α7β2-nAChR selectivity and site of action of these α-CtxPnIC analogs. We determined that α7β2-nAChR selectivity of α-CtxPnIC analogs arises from interactions at a site distinct from the orthosteric agonist-binding site shared between α7β2- and α7-only-nAChR. As numerous previously identified α-Ctx ligands are competitive antagonists of orthosteric agonist-binding sites, this study profoundly expands the scope of use of α-Ctx ligands (which have already provided important nAChR research and translational breakthroughs). More immediately, analogs of α-CtxPnIC promise to enable, for the first time, both comprehensive mapping of the distribution of α7β2-nAChR and detailed investigations of their physiological roles.

A previously unrecognized superfamily of macro-conotoxins includes an inhibitor of the sensory neuron calcium channel Cav2.3

Animal venom peptides represent valuable compounds for biomedical exploration. The venoms of marine cone snails constitute a particularly rich source of peptide toxins, known as conotoxins. Here, we identify the sequence of an unusually large conotoxin, Mu8.1, which defines a new class of conotoxins evolutionarily related to the well-known con-ikot-ikots and 2 additional conotoxin classes not previously described. The crystal structure of recombinant Mu8.1 displays a saposin-like fold and shows structural similarity with con-ikot-ikot. Functional studies demonstrate that Mu8.1 curtails calcium influx in defined classes of murine somatosensory dorsal root ganglion (DRG) neurons. When tested on a variety of recombinantly expressed voltage-gated ion channels, Mu8.1 displayed the highest potency against the R-type (Cav2.3) calcium channel. Ca2+ signals from Mu8.1-sensitive DRG neurons were also inhibited by SNX-482, a known spider peptide modulator of Cav2.3 and voltage-gated K+ (Kv4) channels. Our findings highlight the potential of Mu8.1 as a molecular tool to identify and study neuronal subclasses expressing Cav2.3. Importantly, this multidisciplinary study showcases the potential of uncovering novel structures and bioactivities within the largely unexplored group of macro-conotoxins.

Somatostatin venom analogs evolved by fish-hunting cone snails: From prey capture behavior to identifying drug leads

Somatostatin (SS) is a peptide hormone with diverse physiological roles. By investigating a deep-water clade of fish-hunting cone snails, we show that predator-prey evolution has generated a diverse set of SS analogs, each optimized to elicit specific systemic physiological effects in prey. The increased metabolic stability, distinct SS receptor activation profiles, and chemical diversity of the venom analogs make them suitable leads for therapeutic application, including pain, cancer, and endocrine disorders. Our findings not only establish the existence of SS-like peptides in animal venoms but also serve as a model for the synergy gained from combining molecular phylogenetics and behavioral observations to optimize the discovery of natural products with biomedical potential.

Integrating Venom Peptide Libraries Into a Phylogenetic and Broader Biological Framework

The venomous marine snails are conventionally divided into three groups, the cone snails (family Conidae), the auger snails (family Terebridae) and the turrids (formerly all assigned to a single family, Turridae). In this study, a library of venom peptides from species conventionally assigned to the genus Turris was correlated to a phylogenetic analysis. Nucleotide sequences of multiple genes from transcriptomes were used to assess the phylogenetic relationships across a diverse set of species. The resulting tree shows that as conventionally defined, the conoidean genus Turris, is polyphyletic. We describe a new genus, Purpuraturris gen. nov., that comprises the outlier species. In addition to morphological distinctions, molecular data reveal that this group is divergent from Turris sensu stricto. The correlation between phylogenetic information and a family of peptide sequences was used to highlight those peptides mostly likely to be unique and intimately associated with biological diversity. The plethora of peptide sequences available requires two prioritization decisions: which subset of peptides to initially characterize, and after these are characterized, which to comprehensively investigate for potential biomedical applications such as drug developments. Life Science Identifiers: urn:lsid:zoobank.org; pub: 60D46561-28F0-4C39-BAC4-66DC8B4EAEA4.

Non-Peptidic Small Molecule Components from Cone Snail Venoms

Venomous molluscs (Superfamily Conoidea) comprise a substantial fraction of tropical marine biodiversity (>15,000 species). Prior characterization of cone snail venoms established that bioactive venom components used to capture prey, defend against predators and for competitive interactions were relatively small, structured peptides (10–35 amino acids), most with multiple disulfide crosslinks. These venom components (“conotoxins, conopeptides”) have been widely studied in many laboratories, leading to pharmaceutical agents and probes. In this review, we describe how it has recently become clear that to varying degrees, cone snail venoms also contain bioactive non-peptidic small molecule components. Since the initial discovery of genuanine as the first bioactive venom small molecule with an unprecedented structure, a broad set of cone snail venoms have been examined for non-peptidic bioactive components. In particular, a basal clade of cone snails (Stephanoconus) that prey on polychaetes produce genuanine and many other small molecules in their venoms, suggesting that this lineage may be a rich source of non-peptidic cone snail venom natural products. In contrast to standing dogma in the field that peptide and proteins are predominantly used for prey capture in cone snails, these small molecules also contribute to prey capture and push the molecular diversity of cone snails beyond peptides. The compounds so far characterized are active on neurons and thus may potentially serve as leads for neuronal diseases. Thus, in analogy to the incredible pharmacopeia resulting from studying venom peptides, these small molecules may provide a new resource of pharmacological agents.

Discovery of a Potent Conorfamide from Conus episcopatus Using a Novel Zebrafish Larvae Assay

Natural products such as conotoxins have tremendous potential as tools for biomedical research and for the treatment of different human diseases. Conotoxins are peptides present in the venoms of predatory cone snails that have a rich diversity of pharmacological functions. One of the major bottlenecks in natural products research is the rapid identification and evaluation of bioactive molecules. To overcome this limitation, we designed a set of light-induced behavioral assays in zebrafish larvae to screen for bioactive conotoxins. We used this screening approach to test several unique conotoxins derived from different cone snail clades and discovered that a conorfamide from Conus episcopatus, CNF-Ep1, had the most dramatic alterations in the locomotor behavior of zebrafish larvae. Interestingly, CNF-Ep1 is also bioactive in several mouse assay systems when tested in vitro and in vivo. Our novel screening platform can thus accelerate the identification of bioactive marine natural products, and the first compound discovered using this assay has intriguing properties that may uncover novel neuronal circuitry.

Small-molecule mimicry hunting strategy in the imperial cone snail, Conus imperialis

Venomous animals hunt using bioactive peptides, but relatively little is known about venom small molecules and the resulting complex hunting behaviors. Here, we explored the specialized metabolites from the venom of the worm-hunting cone snail, Conus imperialis Using the model polychaete worm Platynereis dumerilii, we demonstrate that C. imperialis venom contains small molecules that mimic natural polychaete mating pheromones, evoking the mating phenotype in worms. The specialized metabolites from different cone snails are species-specific and structurally diverse, suggesting that the cones may adopt many different prey-hunting strategies enabled by small molecules. Predators sometimes attract prey using the prey's own pheromones, in a strategy known as aggressive mimicry. Instead, C. imperialis uses metabolically stable mimics of those pheromones, indicating that, in biological mimicry, even the molecules themselves may be disguised, providing a twist on fake news in chemical ecology.

Purification and Characterization of the Pink-Floyd Drillipeptide, a Bioactive Venom Peptide from Clavus davidgilmouri (Gastropoda: Conoidea: Drilliidae)

The cone snails (family Conidae) are the best known and most intensively studied venomous marine gastropods. However, of the total biodiversity of venomous marine mollusks (superfamily Conoidea, >20,000 species), cone snails comprise a minor fraction. The venoms of the family Drilliidae, a highly diversified family in Conoidea, have not previously been investigated. In this report, we provide the first biochemical characterization of a component in a Drilliidae venom and define a gene superfamily of venom peptides. A bioactive peptide, cdg14a, was purified from the venom of Clavus davidgilmouri Fedosov and Puillandre, 2020. The peptide is small (23 amino acids), disulfide-rich (4 cysteine residues) and belongs to the J-like drillipeptide gene superfamily. Other members of this superfamily share a conserved signal sequence and the same arrangement of cysteine residues in their predicted mature peptide sequences. The cdg14a peptide was chemically synthesized in its bioactive form. It elicited scratching and hyperactivity, followed by a paw-thumping phenotype in mice. Using the Constellation Pharmacology platform, the cdg14a drillipeptide was shown to cause increased excitability in a majority of non-peptidergic nociceptors, but did not affect other subclasses of dorsal root ganglion (DRG) neurons. This suggests that the cdg14a drillipeptide may be blocking a specific molecular isoform of potassium channels. The potency and selectivity of this biochemically characterized drillipeptide suggest that the venoms of the Drilliidae are a rich source of novel and selective ligands for ion channels and other important signaling molecules in the nervous system.

Transcriptomic Profiling Reveals Extraordinary Diversity of Venom Peptides in Unexplored Predatory Gastropods of the Genus Clavus

Predatory gastropods of the superfamily Conoidea number over 12,000 living species. The evolutionary success of this lineage can be explained by the ability of conoideans to produce complex venoms for hunting, defense, and competitive interactions. Whereas venoms of cone snails (family Conidae) have become increasingly well studied, the venoms of most other conoidean lineages remain largely uncharacterized. In the present study, we present the venom gland transcriptomes of two species of the genus Clavus that belong to the family Drilliidae. Venom gland transcriptomes of two specimens of Clavus canalicularis and two specimens of Clavus davidgilmouri were analyzed, leading to the identification of a total of 1,176 putative venom peptide toxins (drillipeptides). Based on the combined evidence of secretion signal sequence identity, entire precursor similarity search (BLAST), and the orthology inference, putative Clavus toxins were assigned to 158 different gene families. The majority of identified transcripts comprise signal, pro-, mature peptide, and post-regions, with a typically short (<50 amino acids) and cysteine-rich mature peptide region. Thus, drillipeptides are structurally similar to conotoxins. However, convincing homology with known groups of Conus toxins was only detected for very few toxin families. Among these are Clavus counterparts of Conus venom insulins (drillinsulins), porins (drilliporins), and highly diversified lectins (drillilectins). The short size of most drillipeptides and structural similarity to conotoxins were unexpected, given that most related conoidean gastropod families (Terebridae and Turridae) possess longer mature peptide regions. Our findings indicate that, similar to conotoxins, drillipeptides may represent a valuable resource for future pharmacological exploration.

Characterization of the First Conotoxin from Conus ateralbus, a Vermivorous Cone Snail from the Cabo Verde Archipelago

Conus ateralbus is a cone snail endemic to the west side of the island of Sal, in the Cabo Verde Archipelago off West Africa. We describe the isolation and characterization of the first bioactive peptide from the venom of this species. This 30AA venom peptide is named conotoxin AtVIA (δ-conotoxin-like). An excitatory activity was manifested by the peptide on a majority of mouse lumbar dorsal root ganglion neurons. An analog of AtVIA with conservative changes on three amino acid residues at the C-terminal region was synthesized and this analog produced an identical effect on the mouse neurons. AtVIA has homology with δ-conotoxins from other worm-hunters, which include conserved sequence elements that are shared with δ-conotoxins from fish-hunting Conus. In contrast, there is no comparable sequence similarity with δ-conotoxins from the venoms of molluscivorous Conus species. A rationale for the potential presence of δ-conotoxins, that are potent in vertebrate systems in two different lineages of worm-hunting cone snails, is discussed.

α-Conotoxin VnIB from Conus ventricosus is a potent and selective antagonist of α6β4* nicotinic acetylcholine receptors

α6-containing (α6*) nicotinic acetylcholine receptors (nAChRs) are expressed throughout the periphery and the central nervous system and constitute putative therapeutic targets in pain, addiction and movement disorders. The α6β2* nAChRs are relatively well studied, in part due to the availability of target specific α-conotoxins (α-Ctxs). In contrast, all native α-Ctxs identified that potently block α6β4 nAChRs exhibit higher potencies for the closely related α6β2β3 and/or α3β4 subtypes. In this study, we have identified a novel peptide from Conus ventricosus with pronounced selectivity for the α6β4 nAChR. The peptide-encoding gene was cloned from genomic DNA and the predicted mature peptide, α-Ctx VnIB, was synthesized. The functional properties of VnIB were characterized at rat and human nAChRs expressed in Xenopus oocytes by two-electrode voltage clamp electrophysiology. VnIB potently inhibited ACh-evoked currents at rα6β4 and rα6/α3β4 nAChRs, displayed ∼20-fold and ∼250-fold lower potencies at rα3β4 and rα6/α3β2β3 receptors, respectively, and exhibited negligible effects at eight other nAChR subtypes. Interestingly, even higher degrees of selectivity were observed for hα6/α3β4 over hα6/α3β2β3 and hα3β4 receptors. Finally, VnIB displayed fast binding kinetics at rα6/α3β4 (on-rate t_½ = 0.87 min^-1, off-rate t_½ = 2.7 min^-1). The overall preference of VnIB for β4* over β2* nAChRs is similar to the selectivity profiles of other 4/6 α-Ctxs. However, in contrast to previously identified native α-Ctxs targeting α6* nAChRs, VnIB displays pronounced selectivity for α6β4 nAChRs over both α3β4 and α6β2β3 receptors. VnIB thus represents a novel molecular probe for elucidating the physiological role and therapeutic properties of α6β4* nAChRs.

Fish-hunting cone snail venoms are a rich source of minimized ligands of the vertebrate insulin receptor

The fish-hunting marine cone snail Conus geographus uses a specialized venom insulin to induce hypoglycemic shock in its prey. We recently showed that this venom insulin, Con-Ins G1, has unique characteristics relevant to the design of new insulin therapeutics. Here, we show that fish-hunting cone snails provide a rich source of minimized ligands of the vertebrate insulin receptor. Insulins from C. geographus, Conus tulipa and Conus kinoshitai exhibit diverse sequences, yet all bind to and activate the human insulin receptor. Molecular dynamics reveal unique modes of action that are distinct from any other insulins known in nature. When tested in zebrafish and mice, venom insulins significantly lower blood glucose in the streptozotocin-induced model of diabetes. Our findings suggest that cone snails have evolved diverse strategies to activate the vertebrate insulin receptor and provide unique insight into the design of novel drugs for the treatment of diabetes.

Insulin is a hormone critical for maintaining healthy blood sugar levels in humans. When the insulin system becomes faulty, blood sugar levels become too high, which can lead to diabetes. At the moment, the only effective treatment for one of the major types of diabetes are daily insulin injections. However, designing fast-acting insulin drugs has remained a challenge. Insulin molecules form clusters (so-called hexamers) that first have to dissolve in the body to activate the insulin receptor, which plays a key role in regulating the blood sugar levels throughout the body. This can take time and can therefore delay the blood-sugar control.

In 2015, researchers discovered that the fish-hunting cone snail Conus geographus uses a specific type of insulin to capture its prey – fish. The cone snail releases insulin into the surrounding water and then engulfs its victim with its mouth. This induces dangerously low blood sugar levels in the fish and so makes them an easy target. Unlike the human version, the snail insulin does not cluster, and despite structural differences, can bind to the human insulin receptor.

Now, Ahorukomeye, Disotuar et al. – including some of the authors involved in the previous study – wanted to find out whether other fish-hunting cone snails also make insulins and if they differed from the one previously discovered in C. geographus. The insulin molecules were extracted and analyzed, and the results showed that the three cone snail species had different versions of insulin – but none of them formed clusters. Ahorukomeye, Disotuar et al. further revealed that the snail insulins could bind to the human insulin receptors and could also reverse high blood sugar levels in fish and mouse models of the disease.

This research may help guide future studies looking into developing fast-acting insulin drugs for diabetic patients. A next step will be to fully understand how snail insulins can be active at the human receptor without forming clusters. Cone snails solved this problem millions of years ago and by understanding how they have done this, researchers are hoping to redesign current diabetic therapeutics. Since the snail insulins do not form clusters and should act faster than currently available insulin drugs, they may lead to better or new diabetes treatments.

Discovery of Novel Conotoxin Candidates Using Machine Learning

Cone snails (genus Conus) are venomous marine snails that inject prey with a lethal cocktail of conotoxins, small, secreted, and cysteine-rich peptides. Given the diversity and often high affinity for their molecular targets, consisting of ion channels, receptors or transporters, many conotoxins have become invaluable pharmacological probes, drug leads, and therapeutics. Transcriptome sequencing of Conus venom glands followed by de novo assembly and homology-based toxin identification and annotation is currently the state-of-the-art for discovery of new conotoxins. However, homology-based search techniques, by definition, can only detect novel toxins that are homologous to previously reported conotoxins. To overcome these obstacles for discovery, we have created ConusPipe, a machine learning tool that utilizes prominent chemical characters of conotoxins to predict whether a certain transcript in a Conus transcriptome, which has no otherwise detectable homologs in current reference databases, is a putative conotoxin. By using ConusPipe on RNASeq data of 10 species, we report 5148 new putative conotoxin transcripts that have no homologues in current reference databases. 896 of these were identified by at least three out of four models used. These data significantly expand current publicly available conotoxin datasets and our approach provides a new computational avenue for the discovery of novel toxin families.

Tests of a full-scale ITER toroidal interferometer and polarimeter (TIP) prototype on the DIII-D tokamak (invited)

A full-scale ITER toroidal interferometer and polarimeter (TIP) prototype, including an active feedback alignment system, has been installed and tested on the DIII-D tokamak. In the TIP prototype, a two-color interferometry measurement of line-integrated density is carried out at 10.59 μm and 5.22 μm using a CO₂ and quantum cascade laser, respectively, while a separate polarimetry measurement of the plasma-induced Faraday effect is made at 10.59 μm. The TIP prototype is equipped with a piezo tip/tilt stage active feedback alignment system that minimizes noise in the measurement and keeps the diagnostic aligned throughout DIII-D discharges. The measured phase resolution for the polarimeter and interferometer is 0.05° (100 Hz bandwidth) and 1.9° (1 kHz bandwidth), respectively. The corresponding line-integrated density resolution for the vibration-compensated interferometer is δnL = 1.5 × 10¹⁸ m^-2, and the magnetic field-weighted line-integrated density from the polarimeter is δnBL = 1.5 × 10¹⁹ Tm^-2. Both interferometer and polarimeter measurements during DIII-D discharges compare well with the expectations based on calculations using Thomson scattering measured density profiles and magnetic equilibrium reconstructions. Additionally, larger bandwidth interferometer measurements show that the diagnostic is a sensitive monitor of core density fluctuations with demonstrated measurements of Alfvén eigenmodes and tearing modes.

A heterodyne dispersion interferometer for wide bandwidth density measurements on DIII-D

In order to improve both the density and particularly the temporal resolution beyond previous dispersion interferometers (DIs), a heterodyne technique based on an acousto-optic (AO) cell has been added to the DI. A 40 MHz drive frequency for the AO cell allows density fluctuation measurements into the MHz range. A CO₂ laser-based heterodyne DI (HDI) installed on DIII-D has demonstrated that the HDI is capable of tracking the density evolution throughout DIII-D discharges, including disruption events and other rapid transient phenomena. The data also show good agreement with independent density measurements obtained with the existing DIII-D two-color interferometer. The HDI line-integrated density resolution sampled over a 1 s interval is ∼9 × 10¹⁷ m^-2. Density fluctuations induced by MHD instabilities are also successfully measured by the HDI.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Influence of ions on two-dimensional and three-dimensional atomic force microscopy at fluorite-water interfaces

Recent advancement in liquid-environment atomic force microscopy (AFM) has enabled us to visualize three-dimensional (3D) hydration structures as well as two-dimensional (2D) surface structures with subnanometer-scale resolution at solid-water interfaces. However, the influence of ions present in solution on the 2D- and 3D-AFM measurements has not been well understood. In this study, we perform atomic-scale 2D- and 3D-AFM measurements at fluorite-water interfaces in pure water and a supersaturated solution of fluorite. The images obtained in these two environments are compared to understand the influence of the ions in solution on these measurements. In the 2D images, we found clear difference in the nanoscale structures but no significant difference in the atomic-scale contrasts. However, the 3D force images show clear difference in the subnanometer-scale contrasts. The force contrasts measured in pure water largely agree with those expected from the molecular dynamics simulation and the solvent tip approximation model. In the supersaturated solution, an additional force peak is observed over the negatively charged fluorine ion site. This location suggests that the observed force peak may originate from cations adsorbed on the fluorite surface. These results demonstrate that the ions can significantly alter the subnanometer-scale force contrasts in the 3D-AFM images.

A Cost-Effectiveness Analysis of Nintedanib in Idiopathic Pulmonary Fibrosis in the UK

BACKGROUND

International guidelines recommend nintedanib (OFEV^®) as an option for the treatment of idiopathic pulmonary fibrosis (IPF).

OBJECTIVE

The objective of this study was to assess the cost effectiveness of nintedanib versus pirfenidone, N-acetylcysteine and best supportive care (BSC) for the treatment of IPF from a UK payer's perspective.

METHODS

A Markov model was designed to capture the changes in the condition of adults with IPF. Efficacy outcomes included mortality, lung function decline and acute exacerbations. Treatment safety (serious adverse events) and tolerability (overall discontinuation) were also considered. The baseline risk of these events was derived from patient-level data from the placebo arms of nintedanib clinical trials (TOMORROW, INPULSIS-1, INPULSIS-2). A network meta-analysis (NMA) was conducted to estimate the relative effectiveness of the comparator treatments. Quality of life and healthcare resource use data from the clinical trials were also incorporated in the economic model.

RESULTS

Nintedanib showed statistically significant differences against placebo on acute exacerbation events avoided and lung function decline. In the cost-effectiveness analysis, the results were split between two treatments with relative low costs and modest effectiveness (BSC and N-acetylcysteine) and two that showed improved effectiveness (lung function) and higher costs (nintedanib and pirfenidone). All comparators were assumed to have similar projected survival and the difference in quality-adjusted life-years (QALYs) was driven by the acute exacerbations and lung function estimates. In the base-case deterministic pairwise comparison with pirfenidone, nintedanib was found to have fewer acute exacerbations and resulted in less costs and more QALYs gained.

CONCLUSIONS

Compared with BSC (placebo), nintedanib and pirfenidone were the only treatments to show statistical significance in the efficacy parameters. We found substantial uncertainty in the overall cost-effectiveness results between nintedanib and pirfenidone. N-Acetylcysteine was largely similar to BSC but with a worse survival profile. INPULSIS-1 and INPULSIS-2 ClinicalTrials.gov numbers, NCT01335464 and NCT01335477.

Bench testing of a heterodyne CO2 laser dispersion interferometer for high temporal resolution plasma density measurements

A heterodyne detection scheme is combined with a 10.59 μm CO₂ laser dispersion interferometer for the first time to allow large bandwidth measurements in the 10-100 MHz range. The approach employed utilizes a 40 MHz acousto-optic cell operating on the frequency doubled CO₂ beam which is obtained using a high 2nd harmonic conversion efficiency orientation patterned gallium arsenide crystal. The measured standard deviation of the line integrated electron density equivalent phase resolution obtained with digital phase demodulation technique, is 4 × 10¹⁷ m^-2. Air flow was found to significantly affect the baseline of the phase signal, which an optical table cover was able to reduce considerably. The heterodyne dispersion interferometer (DI) approach is found to be robustly insensitive to motion, with measured phase shifts below baseline drifts even in the presence of several centimeters of retroreflector induced path length variations. Plasma induced dispersion was simulated with a wedged ZnSe plate and the measured DI phase shifts are consistent with expectations.

Gamma ray imager on the DIII-D tokamak

A gamma ray camera is built for the DIII-D tokamak [J. Luxon, Nucl. Fusion 42, 614 (2002)] that provides spatial localization and energy resolution of gamma flux by combining a lead pinhole camera with custom-built detectors and optimized viewing geometry. This diagnostic system is installed on the outer midplane of the tokamak such that its 123 collimated sightlines extend across the tokamak radius while also covering most of the vertical extent of the plasma volume. A set of 30 bismuth germanate detectors can be secured in any of the available sightlines, allowing for customizable coverage in experiments with runaway electrons in the energy range of 1-60 MeV. Commissioning of the gamma ray imager includes the quantification of electromagnetic noise sources in the tokamak machine hall and a measurement of the energy spectrum of background gamma radiation. First measurements of gamma rays coming from the plasma provide a suitable testbed for implementing pulse height analysis that provides the energy of detected gamma photons.

PILOT EVALUATION OF A SIMPLE ADJUNCTIVE METHOD FOR IMPROVED REMOVAL OF ORAL BIOFILM DURING CONVENTIONAL SCALING AND ROOT PLANING THERAPY

Various studies have evaluated the adjunctive use of chemical and antimicrobial treatments to assist in the mechanical removal of oral microbial biofilm from tissue surfaces during scaling and root planning therapy (SRP). The current study demonstrates the elimination of two classes of surrogate molecular markers from periodontal disease sites. This suggests the current agent may be a more effective adjunctive cleansing agent for complete biofilm removal. A patient with advanced chronic periodontitis was subjected to standard SRP therapy, supplemented by irrigation with HYBENX® (HBX). Samples of gingival crevicular fluid were collected with triplicate absorbent paper points from each of three quadrants at three time points: 1) at baseline prior to treatment; 2) after irrigation with the topical agent for 20 seconds and rinsing; and 3) after SRP followed by a second irrigation/rinsing treatment with the agent. Paper points were extracted to assess the presence of 13 bacterial species known to be primarily associated with periodontal disease using DNA pyrosequencing. In addition, the presence of Matrix Metalloproteinase-8 (MMP8), as well as IL-1ß, IL-6, and TNF-alpha were also assessed by immunoassay of the paper point sample extracts. The combined adjunctive treatment indicated a complete absence of detectable bacterial DNA and the four inflammatory mediators from samples taken from the gingival sulci treated with HBX. The advantage of the current adjunctive topical treatment technique is that it is simple and easy to administer in conjunction with standard SRP techniques. It appears to provide a level of cleanliness not currently achieved with other SRP adjunctive procedures.

Molecular phylogeny and evolution of the cone snails (Gastropoda, Conoidea)

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. Most of the numerous molecular phylogenies published during the last 15years are limited to rather small fractions of its species diversity. Bayesian and maximum likelihood analyses are mostly congruent and confirm the presence of three previously reported highly divergent lineages among cone snails, and one identified here using molecular data. About 85% of the species cluster in the single Large Major Clade; the others are divided between the Small Major Clade (∼12%), the Conus californicus lineage (one species), and a newly defined clade (∼3%). We also define several subclades within the Large and Small major clades, but most of their relationships remain poorly supported. To illustrate the usefulness of molecular phylogenies in addressing specific evolutionary questions, we analyse the evolution of the diet, the biogeography and the toxins of cone snails. All cone snails whose feeding biology is known inject venom into large prey animals and swallow them whole. Predation on polychaete worms is inferred as the ancestral state, and diet shifts to molluscs and fishes occurred rarely. The ancestor of cone snails probably originated from the Indo-Pacific; rather few colonisations of other biogeographic provinces have probably occurred. A new classification of the Conidae, based on the molecular phylogeny, is published in an accompanying paper.

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

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.

From molecular phylogeny towards differentiating pharmacology for NMDA receptor subtypes

In order to decode the roles that N-methyl-D-aspartate (NMDA) receptors play in excitatory neurotransmission, synaptic plasticity, and neuropathologies, there is need for ligands that differ in their subtype selectivity. The conantokin family of Conus peptides is the only group of peptidic natural products known to target NMDA receptors. Using a search that was guided by phylogeny, we identified new conantokins from the marine snail Conus bocki that complement the current repertoire of NMDA receptor pharmacology. Channel currents measured in Xenopus oocytes demonstrate conantokins conBk-A, conBk-B, and conBk-C have highest potencies for NR2D containing receptors, in contrast to previously characterized conantokins that preferentially block NR2B containing NMDA receptors. Conantokins are rich in γ-carboxyglutamate, typically 17-34 residues, and adopt helical structure in a calcium-dependent manner. As judged by CD spectroscopy, conBk-C adopts significant helical structure in a calcium ion-dependent manner, while calcium, on its own, appears insufficient to stabilize helical conformations of conBk-A or conBk-B. Molecular dynamics simulations help explain the differences in calcium-stabilized structures. Two-dimensional NMR spectroscopy shows that the 9-residue conBk-B is relatively unstructured but forms a helix in the presence of TFE and calcium ions that is similar to other conantokin structures. These newly discovered conantokins hold promise that further exploration of small peptidic antagonists will lead to a set of pharmacological tools that can be used to characterize the role of NMDA receptors in nervous system function and disease.

Biodiversity of cone snails and other venomous marine gastropods: evolutionary success through neuropharmacology

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. Clade divergence within a genus occurs without recruiting new gene families when a saltatory event, such as colonization of new prey types (e.g., fish), leads to a new radiation. Divergence between genera in the same family involves substantial divergence in gene families. In the superfamily Conoidea, the family groups recruited distinct sets of different venom gene superfamilies. The associated morphological, behavioral, and prey-preference changes that accompany these molecular changes are unknown for most conoidean lineages, except for one genus, Conus, for which many associated phenotypic changes have been documented.

Status and characterization of the lithium beam diagnostic on DIII-D

The 30 keV lithium beam diagnostic on DIII-D is suitable to measure both the radial electron density and poloidal magnetic field profiles in the pedestal. The refurbished system features a new setup to measure the Doppler shift allowing accurate alignment of the spectral filters. The injector has been optimized to generate a stable lithium neutral beam with a current of I = 15-20 mA and a diameter of 1.9 ± 0.1 cm measured by beam imaging. The typical temporal resolution is Δt = 1-10 ms and the radial resolution of ΔR = 5 mm is given by the optical setup. A new analysis technique based on fast Fourier transform avoids systematic error contributions from the digital lock-in analysis and accounts intrinsically for background light correction. Latest upgrades and a detailed characterization of the system are presented. Proof-of-principle measurements of the poloidal magnetic field with a statistical error of typically 2% show a fair agreement with the predictions modeled with the Grad-Shafranov equilibrium solver EFIT within 4%.

A systematic review of the evidence on service user involvement in interpersonal skills training of mental health students

Service user involvement has become a common feature of education programmes for mental health students. However, little is known about the effects of this type of education on the interpersonal skills of students taking part. This paper reports findings from a systematic review that formed part of a wider investigation into service user involvement in teaching interpersonal skills. The review aimed to locate and assess the quality of the published evidence relating to the effects of service user involvement on mental health students interpersonal skills and to synthesize results, using a definition of interpersonal skill that includes attitudes, empathy and skills as its key components. Results from this study indicate that the quality of evidence in this area is poor. However, sufficient synthesis of the evidence base was possible to allow conclusions and recommendations for both research and practice. Conclusions were that the involvement of service users in this area is both acceptable and valuable for students and had specific impacts on attitudes, empathy and skills. Some difficulties and reservations about the style of involvement are discussed. Recommendations for the conduct of future research are also made.

Distinct disulfide isomers of μ-conotoxins KIIIA and KIIIB block voltage-gated sodium channels

In the preparation of synthetic conotoxins containing multiple disulfide bonds, oxidative folding can produce numerous permutations of disulfide bond connectivities. Establishing the native disulfide connectivities thus presents a significant challenge when the venom-derived peptide is not available, as is increasingly the case when conotoxins are identified from cDNA sequences. Here, we investigate the disulfide connectivity of μ-conotoxin KIIIA, which was predicted originally to have a [C1-C9,C2-C15,C4-C16] disulfide pattern based on homology with closely related μ-conotoxins. The two major isomers of synthetic μ-KIIIA formed during oxidative folding were purified and their disulfide connectivities mapped by direct mass spectrometric collision-induced dissociation fragmentation of the disulfide-bonded polypeptides. Our results show that the major oxidative folding product adopts a [C1-C15,C2-C9,C4-C16] disulfide connectivity, while the minor product adopts a [C1-C16,C2-C9,C4-C15] connectivity. Both of these peptides were potent blockers of Na(V)1.2 (K(d) values of 5 and 230 nM, respectively). The solution structure for μ-KIIIA based on nuclear magnetic resonance data was recalculated with the [C1-C15,C2-C9,C4-C16] disulfide pattern; its structure was very similar to the μ-KIIIA structure calculated with the incorrect [C1-C9,C2-C15,C4-C16] disulfide pattern, with an α-helix spanning residues 7-12. In addition, the major folding isomers of μ-KIIIB, an N-terminally extended isoform of μ-KIIIA identified from its cDNA sequence, were isolated. These folding products had the same disulfide connectivities as μ-KIIIA, and both blocked Na(V)1.2 (K(d) values of 470 and 26 nM, respectively). Our results establish that the preferred disulfide pattern of synthetic μ-KIIIA and μ-KIIIB folded in vitro is 1-5/2-4/3-6 but that other disulfide isomers are also potent sodium channel blockers. These findings raise questions about the disulfide pattern(s) of μ-KIIIA in the venom of Conus kinoshitai; indeed, the presence of multiple disulfide isomers in the venom could provide a means of further expanding the snail's repertoire of active peptides.

Embedded calibration system for the DIII-D Langmuir probe analog fiber optic links

This paper describes a generally applicable technique for simultaneously measuring offset and gain of 64 analog fiber optic data links used for the DIII-D fixed Langmuir probes by embedding a reference voltage waveform in the optical transmitted signal before every tokamak shot. The calibrated data channels allow calibration of the power supply control fiber optic links as well. The array of fiber optic links and the embedded calibration system described here makes possible the use of superior modern data acquisition electronics in the control room.

Initial results of the high resolution edge Thomson scattering upgrade at DIII-D

Validation of models of pedestal structure is an important part of predicting pedestal height and performance in future tokamaks. The Thomson scattering diagnostic at DIII-D has been upgraded in support of validating these models. Spatial and temporal resolution, as well as signal to noise ratio, have all been specifically enhanced in the pedestal region. This region is now diagnosed by 20 view-chords with a spacing of 6 mm and a scattering length of just under 5 mm sampled at a nominal rate of 250 Hz. When mapped to the outboard midplane, this corresponds to ~3 mm spacing. These measurements are being used to test critical gradient models, in which pedestal gradients increase in time until a threshold is reached. This paper will describe the specifications of the upgrade and present initial results of the system.

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

An impressive biodiversity (>10,000 species) of marine snails (suborder Toxoglossa or superfamily Conoidea) have complex venoms, each containing approximately 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. Each major lineage of Toxoglossa has its own distinct set of venom gene superfamilies. Two recently identified venom gene superfamilies are expressed in the large Turridae clade, but not in Conus. Thus, as major venomous molluscan clades expand, a small set of lineage-specific venom gene superfamilies undergo accelerated evolution. The juxtaposition of extremely conserved signal sequences with hypervariable mature peptide regions is unprecedented and raises the possibility that in these gene superfamilies, the signal sequences are conserved as a result of an essential role they play in enabling rapid sequence evolution of the region of the gene that encodes the active toxin.

A very short, functionally constrained sequence diagnoses cone snails in several Conasprella clades

The traditional taxonomy of ca. 700 cone snails assigns all species to a single genus, Conus Linnaeus 1758. However, an increasing body of evidence suggests that some belong to a phylogenetically distinct clade that is sometimes referred to as Conasprella. Previous work (Kraus et al., 2011) showed that a short (259 bp) conserved intronic sequence (CIS) of the γ-glutamyl carboxylase gene (intron 9) can be used to delineate deep phylogenetic relationships among some groups of Conus. The work described here uses intron 9 (338 bp) to resolve problematic relationships among the conasprellans and to distinguish them from Conus proper. Synapomorphic mutations at just 39 sites can resolve several groups within Conasprella because the informative region of intron 9 is so well conserved that the phylogenetic signal is not obscured by homoplasies at conflicting sites. Intron 9 also unambiguously distinguishes Conasprella as a whole from Conus because the conserved regions that are so well conserved within each group are not alignable and clearly not homologous between them. This pattern suggests that expression of the γ-glutamyl carboxylase gene may have undergone a functionally significant change in Conus or Conasprella shortly after they diverged.

Conantokins derived from the Asprella clade impart conRl-B, an N-methyl d-aspartate receptor antagonist with a unique selectivity profile for NR2B subunits

Using molecular phylogeny has accelerated the discovery of peptidic ligands targeted to ion channels and receptors. One clade of venomous cone snails, Asprella, appears to be significantly enriched in conantokins, antagonists of N-methyl d-aspartate receptors (NMDARs). Here, we describe the characterization of two novel conantokins from Conus rolani, including conantokin conRl-B that has shown an unprecedented selectivity for blocking NMDARs that contain NR2B subunits. ConRl-B shares only some sequence similarity with the most studied NR2B selective conantokin, conG. The divergence between conRl-B and conG in the second inter-Gla loop was used to design analogues for structure-activity studies; the presence of Pro10 was found to be key to the high potency of conRl-B for NR2B, whereas the ε-amino group of Lys8 contributed to discrimination in blocking NR2B- and NR2A-containing NMDARs. In contrast to previous findings for Tyr5 substitutions in other conantokins, conRl-B[L5Y] showed potencies on the four NR2 NMDA receptor subtypes that were similar to those of the native conRl-B. When delivered into the brain, conRl-B was active in suppressing seizures in the model of epilepsy in mice, consistent with NR2B-containing NMDA receptors being potential targets for antiepileptic drugs. Circular dichroism experiments confirmed that the helical conformation of conRl-B is stabilized by divalent metal ions. Given the clinical applications of NMDA antagonists, conRl-B provides a potentially important pharmacological tool for understanding the differential roles of NMDA receptor subtypes in the nervous system. This work shows the effectiveness of coupling molecular phylogeny, chemical synthesis, and pharmacology for discovering new bioactive natural products.

Large variation of vacancy formation energies in the surface of crystalline ice

Resolving the atomic structure of the surface of ice particles within clouds, over the temperature range encountered in the atmosphere and relevant to understanding heterogeneous catalysis on ice, remains an experimental challenge. By using first-principles calculations, we show that the surface of crystalline ice exhibits a remarkable variance in vacancy formation energies, akin to an amorphous material. We find vacancy formation energies as low as ~0.1-0.2 eV, which leads to a higher than expected vacancy concentration. Because a vacancy's reactivity correlates with its formation energy, ice particles may be more reactive than previously thought. We also show that vacancies significantly reduce the formation energy of neighbouring vacancies, thus facilitating pitting and contributing to pre-melting and quasi-liquid layer formation. These surface properties arise from proton disorder and the relaxation of geometric constraints, which suggests that other frustrated materials may possess unusual surface characteristics.

Characterization of a venom peptide from a crassispirid gastropod

The crassispirids are a large branch of venomous marine gastropods whose venoms have not been investigated previously. We demonstrate that crassispirids comprise a major group of toxoglossate snails in a clade distinct from all turrids whose venoms have been analyzed. The isolation and biochemical definition of the first venom component from any crassispirid is described. Crassipeptide cce9a from Crassispira cerithina (Anton, 1838) was purified from crude venom by following biological activity elicited in young mice, lethargy and a lack of responsiveness to external stimuli. Using Edman sequencing and mass spectrometry, the purified peptide was shown to be 29 amino acid residues long, with the sequence: GSCGLPCHENRRCGWACYCDDGICKPLRV. The sequence assignment was verified through the analysis of a cDNA clone encoding the peptide. The peptide was chemically synthesized and folded; the synthetic peptide was biologically active and coelution with the native venom peptide was demonstrated. When injected into mice of various ages, the peptide elicited a striking shift in behavioral phenotype between 14 and 16 days, from lethargy to hyperactivity.

Chemical resolution at ionic crystal surfaces using dynamic atomic force microscopy with metallic tips

We demonstrate that well prepared and characterized Cr tips can provide atomic resolution on the bulk NaCl(001) surface with dynamic atomic force microscopy in the noncontact regime at relatively large tip-sample separations. At these conditions, the surface chemical structure can be resolved yet tip-surface instabilities are absent. Our calculations demonstrate that chemical identification is unambiguous, because the interaction is always largest above the anions. This conclusion is generally valid for other polar surfaces, and can thus provide a new practical route for straightforward interpretation of atomically resolved images.

Against expectation: a short sequence with high signal elucidates cone snail phylogeny

A short (259 nucleotide) conserved intronic sequence (CIS) is surprisingly informative for delineating deep phylogenetic relationships in cone snails. Conus species previously have been assigned to clades based on the evidence from mitochondrial 12S and 16S rRNA gene sequences (1129 bp). Despite their length, these genes lack the phylogenetic information necessary to resolve the relationships among the clades. Here we show that the relationships can be inferred from just 46 sites in the very short CIS sequence (a portion of "intron 9" of the γ-glutamyl carboxylase gene). This is counterintuitive because in short sequences sampling error (noise) often drowns out phylogenetic signal. The intron 9 CIS is rich in synapomorphies that define the divergence patterns among eight clades of worm- and fish-hunting Conus, and it contains almost no homoplasy. Parsimony, maximum likelihood and Bayesian analyses of the combined sequences (mt rRNA+CIS) confirm most of the relationships among 23 Conus sequences. This phylogeny implies that fish-hunting behavior evolved at least twice during the history of Conus-once among New World species and independently in the Indo-Pacific clades.

Characterization of conantokin Rl-A: molecular phylogeny as structure/function study

A multidisciplinary strategy for discovery of new Conus venom peptides combines molecular genetics and phylogenetics with peptide chemistry and neuropharmacology. Here we describe application of this approach to the conantokin family of conopeptides targeting NMDA receptors. A new conantokin from Conus rolani, ConRl-A, was identified using molecular phylogeny and subsequently synthesized and functionally characterized. ConRl-A is a 24-residue peptide containing three gamma-carboxyglutamic acid residues with a number of unique sequence features compared to conantokins previously characterized. The HPLC elution of ConRl-A suggested that this peptide exists as two distinct, slowly exchanging conformers. ConRl-A is predominantly helical (estimated helicity of 50%), both in the presence and absence of Ca(++). The order of potency for blocking the four NMDA receptor subtypes by ConRl-A was NR2B > NR2D > NR2A > NR2C. This peptide has a greater discrimination between NR2B and NR2C than any other ligand reported so far. In summary, ConRl-A is a new member of the conantokin family that expands our understanding of structure/function of this group of peptidic ligands targeted to NMDA receptors. Thus, incorporating phylogeny in the discovery of novel ligands for the given family of ion channels or receptors is an efficient means of exploring the megadiverse group of peptides from the genus Conus.

Defining a Clade by Morphological, Molecular and Toxinological Criteria: Distinctive Forms related to Conus praecellens A. Adams, 1854

We carried out a definition of the species group to which Conus praecellens A. Adams 1854 belongs using a combination of comparative morphological data, molecular phylogeny based on standard genetic markers and toxinological markers. Prior to this work, Conus praecellens was generally postulated to belong to a clade of similarly high-spired, smaller Conusspecies such as Conus pagodus Kiener, 1845, Conus memiae (Habe & Kosuge, 1970) and Conus arcuatus Broderip & Sowerby, 1829. The molecular phylogeny and toxinological data demonstrate that these prior hypotheses are incorrect, and that instead, Conus praecellens is in a branch of Conus that includes Conus stupa (Kuroda, 1956), Conus stupella (Kuroda, 1956), Conus acutangulus Lamark, 1810 and surprisingly, some species that are morphologically strikingly different, Conus mitratus Sowerby, 1870 and Conus cylindraceus Broderip & Sowerby, 1830. A more careful analysis of the morphologically diverse forms assigned to Conus praecellens suggests that from the Philippine material alone, there are at least three additional undescribed species, Conus andremenezi, Conus miniexcelsus and Conus rizali. A reevaluation of protoconch/early teleoconch morphology also strongly suggests that Conus excelsus Sowerby III, 1908 is related to these species. Together, the different data suggest a clade including the 10 species above that we designate, the Turriconus (Shikama and Habe, 1968) (clade; there are additional distinctive forms within the clade that may be separable at the species level. The phylogenetic definition using the multidisciplinary approach described herein provides a framework for comprehensively investigating biodiverse lineages of animals, such as the cone snails.

THE INDO-PACIFIC GEMMULA SPECIES IN THE SUBFAMILY TURRINAE: ASPECTS OF FIELD DISTRIBUTION, MOLECULAR PHYLOGENY, RADULAR ANATOMY AND FEEDING ECOLOGY

The biology, feeding ecology and phylogenetic relationships of marine snails in the family Turridae remain poorly understood. Here we report our study on four deep-water species in the genus Gemmula, a major group in this family. The four species G. speciosa (Reeve 1843), G. sogodensis (Olivera 2005), G. kieneri (Doumet 1940) and G. diomedea (Powell 1964) were collected at five different sites in the Philippines, and their pattern of distribution in the sites, their feeding behaviour as well as their phylogenetic relationships with each other and with other members of the subfamily Turrinae were investigated. The radular morphology (of two Gemmula species) and potential prey (for one Gemmula species) were also examined. Actual feeding observations were also conducted for Gemmula speciosa and compared with two turrids from other genera.All four Gemmula species showed strikingly different patterns of distribution; each species was found to be relatively much more abundant at one site but not at the other sites. Molecular phylogenetic analysis based on 16S sequences correlated with previously reported 12S sequences and revealed that the four species all belong to a well-supported Gemmula clade within the subfamily Turrinae; and that this clade appeared more closely related to the clades Xenuroturris, Turris and Lophiotoma than to the other clades in the subfamily (i.e., Turridrupa, Unedogemmula and Polystira). Morphological analysis of the radula of both G. speciosa and G. sogodensis revealed that the radulae of the two species were similar but differed from the other turrids, Lophiotoma acuta and Unedogemmula bisaya, by the absence of central teeth, consistent with the separation of the Gemmula clade from the Lophiotoma and Unedogemmula clade.To identify the polychaete group that is targeted as prey by species of Gemmula, analysis of regurgitated food fragments was made; phylogenetic analysis of an mtCOI gene fragment that was PCR-amplified from the regurgitated tissue of one specimen (G. diomedea) indicated close affinity of the prey to the terebellid polychaete Amphitritides. Specimens of Gemmula speciosa, when challenged with the terebellid polychaete Loimia sp., were observed to attack the worm suggesting that Gemmula species feed on terebellid polychaetes. Lophiotoma acuta were also observed to feed on the same species of terebellid but were usually group-feeding in contrast to the solitary feeding of G. speciosa. Unedogemmula bisaya did not feed on the terebellid which also supports the separation of the Gemmula and Unedogemmula clade.Two lines of proof (i.e. the molecular phylogenetic analysis and the feeding challenge) supporting the toxin homology findings previously reported, provide consistent evidence that Gemmula is a distinct clade of worm-hunting Turrinae that feeds on Terebellidae.

Evolution of Conus peptide genes: duplication and positive selection in the A-superfamily

A remarkable diversity of venom peptides is expressed in the genus Conus (known as "conotoxins" or "conopeptides"). Between 50 and 200 different venom peptides can be found in a single Conus species, each having its own complement of peptides. Conopeptides are encoded by a few gene superfamilies; here we analyze the evolution of the A-superfamily in a fish-hunting species clade, Pionoconus. More than 90 conopeptide sequences from 11 different Conus species were used to build a phylogenetic tree. Comparison with a species tree based on standard genes reveals multiple gene duplication events, some of which took place before the Pionoconus radiation. By analysing several A-conopeptides from other Conus species recorded in GenBank, we date the major duplication events after the divergence between fish-hunting and non-fish-hunting species. Furthermore, likelihood approaches revealed strong positive selection; the magnitude depends on which A-conopeptide lineage and amino-acid locus is analyzed. The four major A-conopeptide clades defined are consistent with the current division of the superfamily into families and subfamilies based on the Cys pattern. The function of three of these clades (the κA-family, the α4/7-subfamily, and α3/5-subfamily) has previously been characterized. The function of the remaining clade, corresponding to the α4/4-subfamily, has not been elucidated. This subfamily is also found in several other fish-hunting species clades within Conus. The analysis revealed a surprisingly diverse origin of α4/4 conopeptides from a single species, Conus bullatus. This phylogenetic approach that defines different genetic lineages of Conus venom peptides provides a guidepost for identifying conopeptides with potentially novel functions.

Developing evidence-based process maps for spinal cord injury rehabilitation

STUDY DESIGN

Longitudinal audit.

OBJECTIVES

To develop evidence-based maps of rehabilitation for different lesion categories.

SETTING

Midlands, UK.

METHODS

Over a 5-year period data for all newly injured neurologically damaged patients aged 18 years or more were collected and analyzed (n=280). Data were collected from a functional independence measure (the Needs Assessment Checklist), patient records (paper and electronic) and patient goal planning records. The patients were grouped into different lesion categories. Standard milestones that patients in a given category would be expected to reach in rehabilitation were identified using goals set at goal planning meetings. Time when patients reached these milestones and variation between patients around time in reaching these milestones were calculated.

RESULTS

Median times from onset to admission, onset to rehabilitation and length of rehabilitation are given. Pictorial representations of rehabilitation (rehabilitation maps) were produced, using goals identified, median times of achievement and variation. This paper provides examples of these maps from one particular group, T8-T12 Frankel A.

CONCLUSION

Pathways of care can be used in a number of ways: to identify the need for service change; to audit service change; to provide evidence-based expectations for staff, patients and external parties; to look at variances affecting care; to make this service transparent; to provide figures for comparison with other philosophies of care; and to ensure consistency across the service.

Multiple genes elucidate the evolution of venomous snail-hunting Conus species

The species-rich Cone snails (Conus sp.) are predatory, marine gastropods known for small venom peptides that are valuable for pharmacological research applications. Phylogenetic analyses with mitochondrial rRNA sequences have facilitated peptide discovery. However, these relatively conserved genes leave unresolved the closer relationships among many species. We sequenced 26 internal transcribed spacer 2 (ITS2) sequences from genomic ribosomal DNA to elucidate the evolutionary relationships among molluscivorous species and to piscivorous and vermivorous species. We show that ITS2 sequences are well conserved within species but are sufficiently variable among species to resolve recent divergences. Using Bayesian, maximum likelihood and log-determinant methods, we use the ITS sequences to resolve portions of the tree that could not be resolved using the more conventional mt rRNA sequences. When the ITS2 sequences are added to existing COI and to the more conserved rRNA sequences and then properly modeled, support throughout the tree is increased. This enables us to show finer relationships among the molluscivorous species that reveal three well-supported clades (Conus, Cylinder, and Darioconus) and renders the ITS2 sequences an essential component in advancing the discovery and pharmacological characterization of novel peptides from the venoms of these molluscs.