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National Committee on Marine Sciences (NCMS)

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  • Diversity and novelty of venom peptides from Conus (Asprella) rolani revealed by analysis of its venom duct transcriptome
    Taguchi, Ryoichi; Masacupan, Dan Jethro; Lluisma, Arturo (Philippine-American Academy of Science and Engineering, 2024-04-22)
    Conus species in the sub-genus Asprella are poorly studied because they inhabit deep-water habitats. To date, only a few peptides have been characterized from this clade. In this study, the venom duct transcriptome of a member of this clade, Conus rolani, was mined for potential conopeptides. Using a highthroughput RNA sequencing platform (Illumina) and a multiple k-mer de novo assembly, we found 103 putative conopeptide precursor amino acid sequences, including the few peptides previously reported for this species. The sequences, predominantly novel based on amino acid sequence, were diverse, comprising 36 gene superfamilies (including the “unassigned” superfamilies). As observed in other Conus species, the O1 gene superfamily was the most diverse (12 distinct sequences) but interestingly none of the sequences were found to contain the conserved amino acids associated with certain bioactivities in peptides found in piscivorous Conus species. The O2 superfamily was also highly diverse but conikot-ikot and an unassigned superfamily (MMSRMG) were more diverse than the rest of the superfamilies. In terms of gene expression levels, the understudied MEFRR paralog of the ancestral divergent M---L-LTVA superfamily was found to be the most highly expressed in the transcriptome, suggesting a novel role. Additionally, a conopeptide with high sequence similarity to A2 secretory group XII phospholipases is the first reported member of this phospholipase group in Conus and potentially represents a novel superfamily, expanding the catalog of known phospholipases present in cone snail venoms. The discovery of these putative conopeptides provides the first but early glimpse of the diversity and novelty of the peptides in the Asprella group and sets the stage for their functional characterization.
    This work was funded by the Department of Science and Technology- Philippine Council for Health Research and Development (DOST-PCHRD). The collection of C. rolani samples was made possible under Gratuitous Permit No. 0252- 23 granted by the Department of Agriculture — Bureau of Fisheries and Aquatic Resources, Philippines (DA-BFAR). The fieldwork was done with the help of Olango island fishermen, led by Antonio Mosqueda. We extend our gratitude to Antonio Catalig, Zae-Zae Aguinaldo, Kreighton Cadorna, Jonathan Wong, and Niño Dan Posadas for troubleshooting and assisting in the generation of the figures.
  • Genome mining of a novel marine sponge symbiont Nocardia sp. BML-15-R-026U reveals high biosynthetic potential for secondary metabolites, including a non-ribosomal peptide and a polyketide of high novelty
    Gloria, Paul Christian; Romines, Elaine; Punzalan, Marc Jeremie; Florece, Christine Marie; Cadorna, Kreighton; Salvador-Reyes, Lilibeth; Lluisma, Arturo (Philippine-American Academy of Science and Engineering, 2023-11-28)
    Antibiotic and drug resistance poses serious global public health threats, leading to substantial infections and fatalities annually. Addressing these issues requires the discovery of novel bioactive compounds and a faster and more cost-effective discovery process. However, traditional approaches, which require isolation and multi-step purification of compounds from organisms and running of initial assays, suffer from serious limitations such as the need for substantial amounts of biological material and high rates of compound rediscoveries. Because the biosynthetic capabilities of organisms are encoded in their genomes, genome mining provides a promising solution that would complement traditional approaches. This study conducted long-read whole genome sequencing on a marine sponge symbiont, Nocardia sp. BML-15-R-026U, to explore its genomic repertoire of secondary metabolite-encoding Biosynthetic Gene Clusters (BGCs). A four-contig genome assembly was generated for this isolate with a high degree of completeness and an estimated genome size of 4.84 Mbp. Its genome displays remarkable biosynthetic potential by containing at least 34 distinct secondary metabolite BGCs, predominantly Non-Ribosomal Peptide Synthetase (NRPS) and Polyketide Synthase (PKS) systems capable of producing novel chemical structures. Further analysis was focused on two genomic regions. In region 3.10, the study predicted a BGC for a novel, serine-rich non-ribosomal peptide with a predicted molecular weight of 2754 g/mol. Region 3.12 contained an iterative type-I PKS BGC, suggesting the potential synthesis of a polyketide compound with oxidoreductase-inhibiting properties. This study highlights genome mining as a productive early-phase approach for identifying promising drug leads and has identified the most promising candidates among this isolate’s BGCs for experimental validation.
    The study was funded by the Philippine Council for Health Research and Development – Department of Science and Technology under the “Anti-infective and Anticancer Drug Candidates from Marine Microorganisms and Sponges: Discovery and Development” project, Marine Science Institute – UP Diliman. The authors would like to thank the researchers of the Marine Genomics and Molecular Genetics Laboratory, MSI. The authors would also like to thank the researchers of the Discovery and Development of Health Products – Marine Component Phase I and researchers of the Marine Pharmacognosy Laboratory for the collection and initial analysis of the sample used in this study and storage and maintenance of the bacterial cultures. Sample collection was done under Gratuitous Permit No. GP-0084-15.