PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Conus Snail”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14Linked to original sources
PubMed2000

Australian Neuroscience Society--20th Annual Meeting. 30 January-2 February 2000, Melbourne, Australia.

This meeting presented a large array of high quality neuroscience research, some of which held possible relevance for therapeutic development. The potential use of multipotent neural stem cells harvested from adult brain for transplantation and regeneration therapy was highlighted, as was the increasingly central role of the p75 neurotrophin receptor in regulating neuronal cell death. Of particular interest were strategies for the prevention of neuronal death by systemic administration of p75 receptor antisense oligonucleotides. Other significant data included a possible synergy between prostaglandin receptors and opioid receptors in cellular responses, thought to underlie pain perception and opioid analgesia. Groups in Melbourne, Brisbane and Bath, UK, have isolated novel alpha-conotoxins from Conus marine snails, and characterized their effects on neuronal nicotinic acetylcholine receptors (nAChRs), highlighting their subunit specificity and effects on synaptic transmission. While none of these findings are close to effective clinical use as yet, they hold great promise for the future, underlining the necessity for basic research as a starting point for novel therapies.

Journal Article↗
PubMed2005

I-superfamily conotoxins: sequence and structure analysis.

I-superfamily conotoxins have four-disulfide bonds with cysteine arrangement C-C-CC-CC-C-C, and they inhibit or modify ion channels of nerve cells. They have been characterized only recently and are relatively less well studied compared to other superfamily conotoxins. We have detected selective and sensitive sequence pattern for I-superfamily conotoxins. The availability of sequence pattern should be useful in protein family classification and functional annotation. We have built by homology modeling, a theoretical structural 3D model of ViTx from Conus virgo, a typical member of I-superfamily conotoxins. The modeling was based on the available 3D structure of Janus-atracotoxin-Hv1c of Janus-atracotoxin family whose members have been suggested as possible biopesticides. A study comparing the theoretically modeled structure of ViTx, with experimentally determined structures of other toxins, which share functional similarity with ViTx, reveals the crucial role of C-terminal region of ViTx in blocking therapeutically important voltage-gated potassium channels.

Amino Acid Sequence↗
PubMed1991

omega-Conotoxin GVIA receptors of Discopyge electric organ. Characterization of omega-conotoxin binding to the nicotinic acetylcholine receptor.

A peptide toxin from a Conus marine snail, omega-conotoxin GVIA (omega-CgTx) has been used extensively as a probe for certain types of neuronal calcium channels. It is often assumed that omega-CgTx interacts with Ca2+ channels exclusively. We have tested this assumption in a study of omega-CgTx-binding sites in the electric organ of Discopyge ommata. Synaptosomal membranes from this tissue contain low affinity omega-CgTx receptor sites (Kd = 0.6 microM) in great abundance (280 pmol/mg of protein), as first reported by Ahmad and Miljanich (Ahmad, S. N., and Miljanich, G.P. (1988) Brain Res. 453, 247-256). However, we find that a large majority of these omega-CgTx-binding sites co-purify with the nicotinic acetylcholine receptor (nAChR) and can be immunoprecipitated by monoclonal antibodies generated against the nAChR of Torpedo. Cross-linking experiments with radiolabeled omega-CgTx show pronounced specific labeling of the alpha-subunit of the nAChR but not other subunits. Specific omega-CgTx binding to the nAChR is reduced by millimolar Ca2+ but not by alpha- or kappa-bungarotoxin, alpha-conotoxin, or carbamylcholine. Cross-linking experiments also reveal omega-CgTx-binding proteins of 170 and 60 kDa. The characteristics of the 170-kDa protein make it a likely candidate for the alpha 1-subunit of an N-type Ca2+ channel.

Affinity Labels↗
PubMed2004

Conotoxins and structural biology: a prospective paradigm for drug discovery.

Understanding the interactions between activating or antagonizing ligands and their cognate receptors at a molecular level offers promise for the development of pharmacological therapeutics for CNS disorders. The discovery of novel molecules that are capable of discriminating between the varied molecular subunits or isoforms of ion channels should provide a more detailed understanding of the pathophysiology of many CNS disorders. Abundant natural sources of pharmacologically active agents that demonstrate this refined selectivity and specificity are found in the animal toxins of venomous species including: snakes, spiders and the marine snail of the genus Conus. The uniquely fascinating combinatorial ability of the marine snail, genus Conus to modify the pharmacological properties of these neurotoxins or conopeptides within its venom is depicted throughout this review. The myriad of posttranslational modifications and disulfide bonded architectures that have been identified in the conopeptides, are described with an emphasis on the unique pharmacological properties and receptor target specificities that have been ascribed to each of these modifications. The ability of NMR spectroscopy to provide three-dimensional structural information within the interaction interface for both the ligand and target protein following complex formation and its application to conopeptide drug discovery are discussed. Similarly, the strength of merging NMR spectroscopy data with ab initio "restrained soft-docking" for rational pharmacophore design and the identification of lead compounds from in silico library screens will also be discussed. The initial phases of this stratagem are illustrated using two toxin antagonists and the recently determined structure of the KcsA potassium channel. These data exemplify the utility of this approach in elucidating important molecular interfaces of specific toxin-receptor/ion channel complexes, which can be further exploited in drug discovery initiatives.

Animals↗
PubMed2006

Identification and molecular diversity of T-superfamily conotoxins from Conus lividus and Conus litteratus.

The T-superfamily conotoxins comprise a large and diverse group of biologically active peptides and are widely distributed in venom ducts of all major feeding types of Conus. Six novel T-superfamily peptides from the two worm-hunting cone snail species of Conus lividus andConus. litteratus native to Hainan were identified and determined to share a common signal sequence as well as a conserved arrangement of cysteine residues (CC-CC). The predicted mature peptides consist of 11-15 amino acids only. Phylogenetic analyses of new conotoxins from C. lividus andC. litteratus in present study and published homologue T-superfamily sequences from the other Conus species was systematically performed. Phylogenetic trees, residue substitutions to view evolutionary relationships of the precursors' signal, propeptide, and mature toxin regions were explored, as well as residue frequency component and cystine codon usage. Percent divergence of the amino acid sequences of the signal-region exhibited high conservation, whereas the sequences of the mature peptides ranged from high similarity to high divergence between inter- and intro-species. Notably, diversity of pro-peptide region was also high with intermediate percent divergence between that observed in signal and toxin-regions. Consensus hydrophobic residues Leu, Val, Ala, Ile and Pro of signal regions were abundant, whereas among propeptides, basic residues Arg and Lys and acidic residue Asp, addition of hydrophilic residues Thr and Ser were abundant. Residue frequency components were hypervariable in mature toxin region except for highly conservative cystine frame residues. The T-superfamily conotoxins have been previously found mainly in piscivorous and molluscivorous cone snails. The newly identified six T-superfamily peptides described in this investigation exemplify the first to be found from vermivorousC. lividus andC. litteratus. The elucidated cDNAs of the six toxins will facilitate a better understanding of the relationship between structure and function as well as provide a framework for their further research and development.

Amino Acid Sequence↗
PubMed1992

A new bioassay reveals mollusc-specific toxicity in molluscivorous Conus venoms.

Contraction of the foot pedal of a limpet snail is described as a new and quantifiable bioassay for mollusc paralysis. This bioassay was used for screening the venoms of seven different species of Conus snails. Comparison of the results of the limpet assay with those obtained from fish and blowflies shows a correlation between the feeding specificities and venom toxicities of these Conidae. The limpet bioassay should be useful for identification and monitoring of the purification of new toxins active on molluscan systems.

Animals↗