Core A. Abstract. The objective of Core A is to maintain a large collection of venoms and tissues from different Conus species and a collection of purified venom peptides, synthetic peptides and their analogs. Biological material will be obtained mainly from various locations in the Philippines. While the venom will be used as a direct source of purified peptides, tissues will be used as a source of mRNA and genomic DNA for the molecular biological identification of toxins. Peptides will be identified by calcium imaging assay (Project I), testing on heterologously expressed channels and receptors (Projects II and III), and by molecular biological identification of peptide-encoding nucleic acid sequences. Venom peptides will be purified by biochemical methods. From knowledge of the evolutionary relationship among the Conus species we will systematically analyze the venoms for specific ligands. Genetic markers for the cladistic analysis will be obtained by PCR amplification of genomic DNA using specific primers. Complete toxin (pre-pro-mature toxin) sequences will be determined by identification of corresponding cDNAs from cDNA libraries constructed from venom-duct mRNA. PCR amplification of cDNA libraries with family-specific primers will be used to determine the repertoire of expressed toxins. We will use Next Generation sequencing methods to obtain the complete list of toxin sequences and other proteins, expressed in the venom duct. This will enable us to design primers to identify related toxins in other cone snails. We will also implement a conotoxin discovery pipeline combining proteomics and next-gen sequencing by direct analysis of venoms and sequencing the venom-duct transcriptome. Molecular biological methods offer a means of identification of potential ligands (peptides) from very limited amount of biological tissue. The core with extensive molecular biological experience will assist in the detection and quantification of receptors and ion channels expressed in dissociated neurons initially using real-time PCR methods. The peptides isolated by the core are used by all the projects. The equipment requested, is for the production and isolation of the peptides. The real time PCR instrument will be used by the different projects to quantify receptor/channel expression (see equipment budget justification for details). The core will continue to provide peptide and venom samples to the scientific community.