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Toluene, a volatile organic compound, may have adverse effects on the nervous and digestive system when inhaled over an extended period. The assessment of environmental toluene exposure can be effectively conducted by detecting hippuric acid (HA), a toluene metabolite. In this investigation, a molecularly imprinted electrochemical sensor was developed for HA detection, utilizing the synergistic effects of reduced graphene oxide (RGO) and a bimetallic organic skeleton known as CoNi-MOF. Initially, graphene oxide (GO) was synthesized using a modified Hummers' method, and RGO with better conductivity was achieved through reduction with ascorbic acid (AA). Subsequently, CoNi-MOF was introduced to enhance the material's electron transport capabilities further. The molecularly imprinted membrane was then prepared via electropolymerization to enable selective HA recognition. Under optimal conditions, the synthesized sensor exhibited accurate HA detection within a concentration range of 2-800 nM, with a detection limit of 0.97 nM. The sensor's selectivity was assessed using a selectivity coefficient, yielding an imprinting factor of 6.53. The method was successfully applied to the quantification of HA in urine, demonstrating a favorable recovery rate of 93.4%-103.9%. In conclusion, this study presents a practical platform for the detection of human metabolite detection., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Climate change is affecting the distribution of marine organisms worldwide, including venomous marine gastropods that offer risks to human health, but also potential pharmacological resources, such as Conus sp. Species Distribution Models (SDMs) are valuable tools for predicting species distribution under climate change. The objective of our study was to evaluate the potential distribution of Conus geographus and C. textile in the Indo-Pacific region under different climate change scenarios for 2050 and 2090. We constructed SDMs with MaxEnt for each species, using bioclimatic variables from Bio-ORACLE and NOAA, and occurrence data from GBIF. We projected the best-fit model for the present and different future climate change scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, SSP5-8.5). We obtained high accuracy SDMs for C. geographus and C. textile, with Temperature and Primary Productivity as the main explanatory variables. Our future projections reveal that both species may react differently to climate change. Southeast Asia and Micronesia will continue to provide a climatically appropriate environment for both species; however, they may become more suitable for C. geographus and less suitable for C. textile. This may lead to a higher risk of human envenomation by C. geographus, but a lower risk by C. textile. A decreased suitability for C. textile may also lead to the loss of potential pharmacological resources among its range. Our study emphasizes how SDMs can be used to assess the future distribution of species with human health implications, which can aid in the monitoring of venomous marine species., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The cone snail Conus betulinus is a vermivorous species that is widely distributed in the South China Sea. Its crude venom contains various peptides used to prey on marine worms. In previous studies, a systematic analysis of the peptide toxin sequences from C. betulinus was carried out using a multiomics technique. In this study, 10 cysteine-free peptides that may possess insecticidal activity were selected from a previously constructed conopeptide library of C. betulinus using the CPY-Fe conopeptide as a template. These conopeptides were prepared by solid-phase peptide synthesis (SPPS), then characterized by the reverse-phase high performance liquid chromatography (HPLC) and mass spectrometry. Insect cytotoxicity and injection experiments revealed that these cysteine-free peptides exerted favorable insecticidal effects, and two of them (Bt010 and Bt016) exhibited high insecticidal efficacy with LD50 of 9.07 nM and 10.93 nM, respectively. In addition, the 3D structures of these peptides were predicted by homology modeling, and a phylogenetic tree was constructed based on the nucleotide data of conopeptides to analyze the relationships among structures, functions, and evolution. A preliminary mechanism for the insecticidal activity of the cysteine-free conopeptides was predicted by molecular docking. To the best of our knowledge, this is the first study to report the insecticidal activity of cysteine-free conopeptides derived from Conus betulinus, signaling that they could potentially be developed into bioinsecticides with desirable properties such as easy preparation, low cost, and high potency., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Developing highly efficient, stable, recyclable, and application value heterogeneous catalysts in advanced oxidation processes has essential application value in the degradation of refractory pollutants. In this paper, the CoNi alloy anchored onto N-doped porous carbon (CoNi-600@NC) catalyst was prepared using bimetallic doped metal-organic frameworks as precursors. The magnetic CoNi-600@NC can activate peroxymonosulfate (PMS) to degrade sulfamethoxazole (SMX). Therefore, SMX can be removed 100% within 25 min. CoNi-600@NC/PMS has a broad pH (3-9) application range, good applicability, and repeatability. Radical quenching, quantitative and electrochemical experiments proved that the degradation of SMX was dominated by free radical (Superoxide anions) and non-free radical pathways (surface-bound radicals). Mechanistic analysis showed that the interaction between Co-N x /pyridine N-sites and graphitized carbon with PMS induced the formation of surface-bound active species. Moreover, CoNi nanoparticles promoted the redox cycle of metals. The synergistic catalytic mechanisms between the CoNi alloy and the abundant functional groups gave CoNi-600@NC excellent catalytic properties and applicability. Using density functional theory predicted the reaction sites of SMX and proposed four degradation pathways. The toxicity of intermediates was comprehensively evaluated. In addition, a CoNi-600@NC continuous flow reactor was constructed with a daily treatment capacity of 45 L and 100% SMX removal. This study expands the application of persulfate advanced oxidation technology by synthesizing recyclable magnetic catalysts and provides new synergistic degradation mechanisms for removing refractory organics., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Taste and odor (T&O) compounds are important water pollutant, some of which are toxic. The relevant studies are all expand upon the well-known T&O compounds but for the unknown odors in smelling water. In this work, a method combining purge and trap with gas chromatograph-mass spectrometer (PT-GC/MS) and disperse solid-phase extraction with gas chromatograph (GC) was first proposed to detect T&O compounds in unknown odorous water accurately. Firstly, PT-GC/MS was used for a qualitative test on unknown odors in smelling water and determine the analytes. The hollow CoNi-layered double hydroxide (LDH) on graphene oxide (GO) was then used as a composite adsorbent to pretreat the water, in which the GO provided large specific surface, and the LDH worked as a confinement cavity to enhance capture and retention capacity for volatile organic compounds (VOCs). According to the properties of T&O compounds determined by PT-GC/MS in water, a corresponding GC method was established for accurately quantitative analysis. In this paper, five T&O compounds were detected simultaneously, including dimethyl sulfide, meistylene, N, N-dimethylbenzylamine, 2, 4-dimethylbenzaldehyde and 2, 4-di-tert-butylphenol. Extraction parameters were optimized, including ratio of desorption solvent, amount of adsorbent, pH value, etc. Under the optimal conditions, the detection limits for analysis were 1.14 μg/L to 3.07 mg/L. The satisfactory recoveries were 94-98%. Furthermore, two optimal determination outcomes of odor waters from different places support the practicability of the method, which is expected to be widely used in the detection of unknown odors in smelling water., (Copyright © 2022 Elsevier B.V. All rights reserved.)

In this study, a series of one-dimensional (1D)/two-dimensional (2D) heterostructure hybrids were fabricated through the in situ growth of a Co and Ni bimetallic zeolitic imidazolate framework (CoNi-ZIF) around N-doped carbon nanotubes (N-CNTs). The hybrids were further exploited as effective supercapacitor materials. The N-CNTs were prepared by carbonizing a mixture of glucose and the melamine-cyanuric acid complex at a high temperature (900 °C) under N 2 atmosphere and applied as the template for the in situ synthesis of CoNi-ZIF nanosheets (NSs). The 1D N-CNTs in the hybrids can act as the high-way for charge transfer to boost the faradaic reactions. Changing the usage of metal precursors not only provided abundant redox reaction sites in 2D CoNi-ZIF NSs but also modulated the microstructures and chemical components of the hybrids. The integration of the features of N-CNTs and CoNi-ZIF NSs can result in a synergistic effect between N-CNTs and CoNi-ZIF NSs. Therefore, the obtained CoNi-ZIFs and N-CNTs hybrid (CoNi-ZIF@N-CNT) exhibited superior electrochemical capacitive performance. Comparison revealed that the CoNi-ZIF@N-CNT-2 hybrid, which was prepared with a 1:1 mass ratio of Co(NO 3 ) 2 ·6H 2 O and Ni(NO 3 ) 2 ·6H 2 O, displayed the largest specific capacitance of 1118F g -1 at 1 A g -1 , which was higher than the capacitance of most reported metal-organic framework (MOF)-based supercapacitor electrodes. Moreover, the asymmetric supercapacitor based on the CoNi-ZIF@N-CNT-2 electrode exhibited a high energy density of 51.1 Wh kg -1 at the power density of 860.1 W kg -1 and good cycle stability. This work can provide a facile and effective way for the fabrication of heterostructured 1D/2D nanostructures based on 2D MOFs for advanced energy storage., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Inc. All rights reserved.)

It is a significant challenge to combine a large pseudocapacitive material with conductive honeycomb-like carbon frameworks for long-term stable supercapacitors. Herein, hierarchical composite materials are manufactured by using biomass carbon, ZIF-67, and a mild pore former (Ni(CH 3 COO) 2 ) to generate alloy-type CoNi 3 nanoparticles planted into conductive honeycomb-like carbon frameworks (C@ZIF-67-T). Meanwhile, the effect of carbonization temperature on the honeycomb-like pore size and the structure of composite materials is systematically investigated. As the honeycomb-like carbon skeleton structure guarantees good ionic and electronic conductivities and a large contact area, whereas the alloy nanoparticles provide a rich redox reaction for Faradaic capacitance. Therefore, the as-obtained C@ZIF-67-600 electrode presents a remarkable specific capacitance of 1044.8 F · g -1 at 1.0 A · g -1 and an ultra-long cycling stability with 30,000 cycles at 5.0 A · g -1 in a three-electrode system. In addition, the assembled C@ZIF-67-600//activated carbon asymmetrical supercapacitor exhibit a high specific capacitance of 274.4F · g -1 at 1.0 A · g -1 and a long-term stable lifespan with a capacitance retention of 87% after 20,000 cycles at 5.0 A · g -1 . Besides, the asymmetrical supercapacitor also presents a maximum energy density of 85.13 Wh · kg -1 at a power density of 750 W · kg -1 . Such superior electrochemical performance demonstrate that the designed electrode material provides a promising energy storage application., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Simultaneous electrochemical determination of 4-aminophenol (4-AP) and acetaminophen (ACOP) is crucial due to their high toxicity when are overused. Herein, a novel electrocatalyst of nitrogen-doped carbon coated CoNi alloy (CoNi@CN) is derived from bimetallic CoNi(BDC) 2 (DABCO) for the first time. A series of characterizations demonstrate that composite has been successfully synthesized, and all elements are evenly distributed in the catalyst. The optimal sensor based on Co 1 Ni 1 @CN-700 exhibits two wide linear responses for 4-AP (0.05-60 μM and 60-250 μM) and ACOP (0.05-40 μM and 40-150 μM) with the lowest detection limit of 5.2 nM and 3.8 nM compared with current known reports. Moreover, the sensor has superior reproducibility, selectivity and stability. In addition, the wonderful recoveries also are obtained when sensor is used to detect 4-AP and ACOP in real samples, illustrating that electrochemical sensor has great prospect in the clinical application., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The venom of various Conus species is composed of a rich variety of unique bioactive peptides, commonly referred to as conotoxins (conopeptides). Most conopeptides have specific receptors or ion channels as physiologically relevant targets. In this paper, high-throughput transcriptome sequencing was performed to analyze putative conotoxin transcripts from the venom duct of a vermivorous cone snail species, Conus litteratus native to the South China Sea. A total of 128 putative conotoxins were identified, most of them belonging to 22 known superfamilies, with 43 conotoxins being regarded as belonging to new superfamilies. Notably, the M superfamily was the most abundant in conotoxins among the known superfamilies. A total of 15 known cysteine frameworks were also described. The largest proportion of cysteine frameworks were VI/VII (C-C-CC-C-C), IX (C-C-C-C-C-C) and XIV (C-C-C-C). In addition, five novel cysteine patterns were also discovered. Simple sequence repeat detection results showed that di-nucleotide was the major type of repetition, and the codon usage bias results indicated that the codon usage bias of the conotoxin genes was weak, but the M, O1, O2 superfamilies differed in codon preference. Gene cloning indicated that there was no intron in conotoxins of the B1- or J superfamily, one intron with 1273-1339 bp existed in a mature region of the F superfamily, which is different from the previously reported gene structure of conotoxins from other superfamilies. This study will enhance our understanding of conotoxin diversity, and the new conotoxins discovered in this paper will provide more potential candidates for the development of pharmacological probes and marine peptide drugs.

Introduction: Spasticity is the result of an exaggeration of the monosynaptic muscle stretch reflex due to lesions affecting the central nervous system, in particular an upper motor neuron lesion. Selective dorsal rhizotomy (SDR) is a surgical technique developed to treat spastic diplegia, one of the common forms of cerebral palsy, resulting from the lack of supraspinal inhibitory controls. The aim of SDR is to identify and cut a critical amount of the sensory rootlets, in particular those contributing the most to spasticity, in order to relieve the patient from lower limb spasticity while preserving motor strength and sphincter control. Various surgical techniques to perform SDR have been proposed over time. Similarly, intraoperative neurophysiology (ION)-first introduced by Fasano and colleagues in 1976-is a safe and effective tool to guide the surgeon in the procedure of SDR, but different ION strategies are used by different authors, and the value of ION itself has been questioned., Methods: The purpose of this paper is to review the anatomo-physiological background of SDR, the historical development of the surgical technique, and the essential principles of ION., Results: While some surgeons privilege a single-level approach and others a multi-level approach, nowadays, there are still neither agreement nor guidelines on the percentage of roots to be cut. Rather, a tailored approach based on both the preoperative functional status as well as intraoperative ION findings seems reasonable. ION is considered not essential to decide the percentage of roots to cut, but it assists to distinguish between ventral and dorsal roots, and to preserve sphincterial function, whenever S2 rootlets are included in SDR., Conclusions: To optimize the balance between reduction of spasticity and preservation of motor strength while minimizing the neurological damage remains the main goal of SDR.

Putative prolyl-4-hydroxylase (P4H) α-subunit sequences have been extracted by mining transcriptomic data obtained from seven cone snail species C. amadis, C. monile, C. araneosus, C. miles, C. litteratus, C. frigidus, and C. ebraeus. Sequences ranging from 518 to 559 residues have been compared with representative animal P4H sequences. The α-subunit consists of an N-terminus double domain, involved in dimerization and substrate binding, while the C-terminus contains the catalytic domain. Definitive functional annotation of the cone snail sequences has been achieved by an analysis of conserved residues responsible for catalytic function, specific conformational features, and subunit interactions, using two independent structures of the double domain, and the catalytic domain, previously reported in the literature. The variability of proline hydroxylation in conotoxins is illustrated by a mass spectrometric analysis of C. amadis venom. Site specific hydroxylation and the presence of peptides with multiple proline residues, resistant to modification, suggests that sequence and conformational effects may determine the substrate specificity of the Conus prolyl-4-hydroxylases. SIGNIFICANCE: Proline hydroxylation is a widely observed post translational modification, with collagen being the pre-eminent example. Hydroxylation of proline is also widely observed in conotoxins, which are a major component of marine cone snail venom. This paper describes newly identified prolyl-4-hydroxylase sequences, using transcriptome data from seven Conus species. The predicted functional annotation of prolyl-4-hydroxylase sequences was carried out using two available crystal structures of independent domains. The mass spectrometric characterisation of proline/hydroxyproline containing peptides in C. amadis venom confirms sequence specific hydroxylation in Conus venom as shown previously by others., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Objective: This paper provides the first compilation in more than 30 years of human injuries and fatalities from envenomation by marine gastropod molluscs of the predominantly tropical family Conidae. It seeks to apply recent advances in knowledge of the physiological effects of conopeptides and molecular genetics to improve our understanding of the human responses to stings by species that normally use their venom peptides to paralyze and overcome prey such as polychaete worms, other gastropod molluscs, and fishes., Results: A database has been constructed for the 139 cases accepted as reliably reporting each human injury. It includes data on the species responsible, the time and place where the stinging occurred and the sting site on the victim's body, the time-course of clinical effects, treatment carried out, if any, and outcome. Members of the hyperdiverse genus Conus caused all the injuries, except for 2 cases involving species from the recently separated genus Conasprella. Death occurred in 36 cases, 57 cases presented with serious symptoms but recovered completely, and in 44 cases victims were only minimally affected. A few cases are listed as tentative because the information in the reports was limited or unverifiable. Many cases have undoubtedly gone unreported and been forgotten. No cases are known for the period between the date of the first reliable report in the 17th century, and the mid-19th century. Knowledge of conopeptide molecular structure and function has recently burgeoned, permitting initial exploration of relationships between the symptoms and outcomes of human injuries and modes of action of these mainly small, very toxic neuroactive peptides. These relationships are reviewed here, especially in regard to the severe and fatal cases, with the aim of making recent knowledge accessible to clinicians and others involved in treating the effects of human stings, which continue to be reported., Conclusions: Conus geographus, a specialized predator of fishes, which it paralyzes with its venom and swallows whole, is the most dangerous species to humans. It accounts for about half of the known human envenomations and almost all the fatalities. Children succumb more often to C. geographus stings than adults and stings by larger snails are lethal more often than stings from smaller snails, regardless of the victim's age. Other piscivorous Conus species have stung humans, but with nonlethal results. A few species that normally prey on other gastropods have also seriously injured humans, but most of the fatalities reported have not been confirmed. Most species of Conidae prey only on marine worms; 18 of these species are known to have stung humans, with generally mild effects. Research on the treatment of Conus stings has lagged behind that on the application of conopeptides in pharmacological research and in the development of new pharmaceuticals. However, improved communication and availability of medical aid in remote tropical areas has likely contributed to reducing the mortality rate during the last half century.

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., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Bioactive peptides from Conus venom contain a natural abundance of post-translational modifications that affect their chemical diversity, structural stability, and neuroactive properties. These modifications have continually presented hurdles in their identification and characterization. Early endeavors in their analysis relied on classical biochemical techniques that have led to the progressive development and use of novel proteomic-based approaches. The critical importance of these post-translationally modified amino acids and their specific assignment cannot be understated, having impact on their folding, pharmacological selectivity, and potency. Such modifications at an amino acid level may also provide additional insight into the advancement of conopeptide drugs in the quest for precise pharmacological targeting. To achieve this end, a concerted effort between the classical and novel approaches is needed to completely elucidate the role of post-translational modifications in conopeptide structure and dynamics. This paper provides a reflection in the advancements observed in dealing with numerous and multiple post-translationally modified amino acids within conotoxins and conopeptides and provides a summary of the current techniques used in their identification.

Conotoxins are a diverse collection of more than 50,000 peptides produced by predatory marine snails of the genus Conus in order to immobilize their prey. Many conotoxins modulate the activity of ion channels, and show high specificity to their targets; as a result, some have valuable pharmaceutical applications. However, obtaining active peptide is difficult and to date has only been achieved though natural collection, chemical synthesis, or the use of prokaryotic expression systems, which often have the disadvantage of requiring subsequent steps to correctly fold the peptide. This paper reports the production of a conotoxin, TxVIA from Conus textile, as a biologically active recombinant protein, using the yeast Pichia pastoris as expression host. The presence of the pro-peptide was found to be necessary for the expression of biologically active conotoxin. We also show that TxVIA is not, as previously reported, mollusc-specific, but also shows insecticidal activity when injected into lepidopteran (cabbage moth) and dipteran (house fly) larvae. In contrast, recombinant TxVIA was not found to be molluscicidal to the grey field slug Deroceras reticulatum., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Background: Conotoxin has been proven to be effective in drug design and could be used to treat various disorders such as schizophrenia, neuromuscular disorders and chronic pain. With the rapidly growing interest in conotoxin, accurate conotoxin superfamily classification tools are desirable to systematize the increasing number of newly discovered sequences and structures. However, despite the significance and extensive experimental investigations on conotoxin, those tools have not been intensively explored., Results: In this paper, we propose to consider suboptimal alignments of words with restricted length. We developed a scoring system based on local alignment partition functions, called free score. The scoring system plays the key role in the feature extraction step of support vector machine classification. In the classification of conotoxin proteins, our method, SVM-Freescore, features an improved sensitivity and specificity by approximately 5.864% and 3.76%, respectively, over previously reported methods. For the generalization purpose, SVM-Freescore was also applied to classify superfamilies from curated and high quality database such as ConoServer. The average computed sensitivity and specificity for the superfamily classification were found to be 0.9742 and 0.9917, respectively., Conclusions: The SVM-Freescore method is shown to be a useful sequence-based analysis tool for functional and structural characterization of conotoxin proteins. The datasets and the software are available at http://faculty.uaeu.ac.ae/nzaki/SVM-Freescore.htm.

Cone snails are carnivorous marine gastropods that have evolved potent venoms to capture their prey. These venoms comprise a rich and diverse cocktail of peptide toxins, or conopeptides, whose high diversity has arisen from an efficient hypermutation mechanism, combined with a high frequency of post-translational modifications. Conopeptides bind with high specificity to distinct membrane receptors, ion channels, and transporters of the central and muscular nervous system. As well as serving their natural function in prey capture, conopeptides have been utilized as versatile tools in neuroscience and have proven valuable as drug leads that target the nervous system in humans. This paper examines current knowledge on conopeptide sequences based on an analysis of gene and peptide sequences in ConoServer (http://www.conoserver.org), a specialized database of conopeptide sequences and three-dimensional structures. We describe updates to the content and organization of ConoServer and discuss correlations between gene superfamilies, cysteine frameworks, pharmacological families targeted by conopeptides, and the phylogeny, habitat, and diet of cone snails. The study identifies gaps in current knowledge of conopeptides and points to potential directions for future research.

The M-superfamily of conotoxins currently comprises three major groups of peptides (the mu-, kappaMu-, and psi-families) that share a key structural characteristic, the six-cysteine motif CC-C-C-CC, but differ with respect to their molecular targets. The psi-family consists of M-superfamily conotoxins that are nicotinic acetylcholine receptor (nAChR) antagonists. To date, only two psi-conotoxins, PIIIE and PIIIF, are known, both of which were isolated from a single Conus species, Conus purpurascens. In this paper, we report the discovery and initial characterization of a psi-conotoxin from another Conus species, Conus parius, which we designated as PrIIIE. Its amino acid sequence, inferred from a cloned cDNA, differed significantly from those of PIIIE and PIIIF. Its bioactivity was investigated by using the synthetic form of the peptide in mice and fish bioassays. At 2.5 nmol, the synthetic peptide induced flaccid paralysis in goldfish in ca. 4 min but did not induce any remarkable behavior in mice (after i.c. and i.p. injection of up to 10 nmol of peptide) and did not block action potential in directly stimulated frog muscle preparations. Electrophysiological experiments carried out to measure inhibition of ion currents through mouse nAChR receptors expressed in oocytes revealed that PrIIIE (IC(50) approximately 250 nM) was significantly more potent than PIIIE (IC(50) approximately 7000 nM) and that PrIIIE showed higher inhibition potency against the adult-type than the fetal-type nAChR. In similar electrophysiological assays, PrIIIE showed no inhibitory effects against the mouse muscle subtype Na(+) channel isoform Na(v) 1.4. The discovery of this psi-conotoxin from a Conus species that belongs to the subgenus Phasmoconus, which is distinct from and larger than the clade in which C. purpurascens belongs, suggests that greater structural and functional diversity of psi-conotoxins remains to be discovered from the members of this subgenus.

Vasopressins and oxytocins are homologous, ubiquitous and multifunctional peptides present in animals. Conopressins are vasopressin/oxytocin-related peptides that have been found in the venom of cone snails, a genus of marine predatory molluscs that envenom their prey with a complex mixture of neuroactive peptides. In the present paper, we report the purification and characterization of a unique conopressin isolated from the venom of Conus villepinii, a vermivorous cone snail species from the western Atlantic Ocean. This novel peptide, designated gamma-conopressin-vil, has the sequence CLIQDCPgammaG* (gamma is gamma-carboxyglutamate and * is C-terminal amidation). The unique feature of this vasopressin/oxytocin-like peptide is that the eighth residue is gamma-carboxyglutamate instead of a neutral or basic residue; therefore it could not be directly classified into either the vasopressin or the oxytocin peptide families. Nano-NMR spectroscopy of the peptide isolated directly from the cone snails revealed that the native gamma-conopressin-vil undergoes structural changes in the presence of calcium. This suggests that the peptide binds calcium, and the calcium-binding process is mediated by the gamma-carboxyglutamate residue. However, the negatively charged residues in the sequence of gamma-conopressin-vil may mediate calcium binding by a novel mechanism not observed in other peptides of this family.