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National Committee on Marine Sciences (NCMS)

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SDG: search.filters.sdg.SDG 3 - Good health and well-beingUNESCO Keyword: search.filters.subject.Marine biology

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    Global mass spectrometric analysis reveals chemical diversity of secondary metabolites and 44-Methylgambierone production in Philippine Gambierdiscus strains
    Malto, Zabrina Bernice L.; Benico, Garry A.; Batucan, Jeremiah D.; Dela Cruz, James; Romero, Marc Lawrence J.; Azanza, Rhodora V.; Salvador-Reyes, Lilibeth A. (Frontiers Media SA, 2022-02-04)
    Surveillance and characterization of emerging marine toxins and toxigenic dinoflagellates are warranted to evaluate their associated health risks. Here, we report the occurrence of the ciguatera poisoning-causative dinoflagellate Gambierdiscus balechii in the Philippines. Toxin production and chemical diversity of secondary metabolites in G. balechii GtoxSAM092414, G. balechii Gtox112513, and the recently reported Gambierdiscus carpenteri Gam1BOL080513 were assessed using targeted and untargeted UPLC-MS/MS analysis and radioligand receptor-binding assay (RBA). 44-methylgambierone was produced by all three strains, albeitwith different levels based on RBA and UPLC-HRMS/MS analysis. The fatty acid composition was similar in all strains, while subtle differences in monosaccharide content were observed, related to the collection site rather than the species. Molecular networking using the GNPS database identified 45 clusters belonging to at least ten compound classes, with terpene glycosides, carbohydrate conjugates, polyketides, and macrolides as major convergence points. Species-specific peptides and polyhydroxylated compounds were identified in G. balechii GtoxSAM092414 and G. carpenteri Gam1BOL080513, respectively. These provide a glimpse of the uncharacterized biosynthetic potential of benthic dinoflagellates and highlight the intricate and prolific machinery for secondary metabolites production in these organisms.
    We would like to thank H. Junio and the Secondary Metabolites Profiling Laboratory of the Institute of Chemistry, University of the Philippines Diliman and K. B. Davis for assistance in the conduct of this study.
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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.
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    Physicochemical and biochemical characterization of collagen from Stichopus cf. horrens tissues for use as stimuli-responsive thin films
    Sisican, Kim Marie D.; Torreno, Vicenzo Paolo M.; Yu, Eizadora T.; Conato, Marlon T. (American Chemical Society, 2023-09-20)
    The mutable collagenous tissue (MCT) of sea cucumber, with its ability to rapidly change its stiffness and extensibility in response to different environmental stress conditions, serves as inspiration for the design of new smart functional biomaterials. Collagen, extracted from the body wall of Stichopus cf. horrens, a species commonly found in the Philippines, was characterized for its suitability as stimuli-responsive films. Protein BLAST search showed the presence of sequences commonly found in type VII and IX collagen, suggesting that Stichopus horrens collagen is heterotypic. The maximum transition temperature recorded was 56.0 ± 2 °C, which is higher than those of other known sources of marine collagen. This suggests that S. horrens collagen has better thermal stability and durability. Collagen-based thin films were then prepared, and atomic force microscopy (AFM) imaging showed the visible collagen network comprising the films. The thin films were subjected to thermomechanical analysis with degradation starting at >175 °C. At 100–150 °C, the collagen-based films apparently lose their translucency due to the removal of moisture. Upon exposure to ambient temperature, instead of degrading, the films were able to revert to the original state due to the readsorption of moisture. This study is a demonstration of a smart biomaterial developed from S. cf. horrens collagen with potential applications in food, pharmaceutical, biomedical, and other collagen-based research.
    This research was funded by the Philippine Council for Agriculture, Aquatic, and Natural Resources Research and Development of the Department of Science and Technology (DOST-PCAARRD).