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National Committee on Marine Sciences (NCMS)

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    In Silico supported nontarget analysis of contaminants of emerging concern: Increasing confidence in unknown identification in wastewater and surface waters
    Angeles, Luisa F.; Halwatura, Lahiruni M.; Antle, Jonathan P.; Simpson, Scott; Jaraula, Caroline M.B.; Aga, Diana S. (American Chemical Society, 2021-08-01)
    Nontarget analysis using liquid chromatography–high resolution mass spectrometry (LC–HRMS) is a valuable approach in characterizing for contaminants of emerging concern (CECs) in the environment. In this study, wastewater and surface water samples from three locations in Manila, Philippines were analyzed for CECs using a nontarget analysis approach with an LC-Orbitrap. A previously optimized semiautomated workflow was used for data processing with Compound Discoverer. A total of 157 compounds were identified, with 21 confirmed with reference standards, 83 confirmed with evidence from a mass spectral library (mzCloud), and 53 tentatively identified using in silico fragmentation (MetFrag). These compounds include pharmaceuticals such as antibiotics, antifungal, and antihypertensive compounds, human metabolites, natural products, pesticides, and industrial chemicals. Compounds confirmed with reference standards include antibiotics ciprofloxacin, clarithromycin, acetyl-sulfamethoxazole, and trimethoprim (2 to 19 ng/L), and antifungal compounds carbendazim and climbazole (3–47 ng/L). The pesticides diethyltoluamide (DEET) and diuron were also detected (37 ng/L). The utility of a preliminary multivariable linear regression quality structure-retention relationship (QSRR) model based on quantum chemical molecular descriptors is demonstrated. This study demonstrates the importance of using tools and software that are helpful for annotating HRMS data and reporting detections according to a standardized classification system. The detection of several CECs in wastewater and surface water samples show the importance of performing nontarget analysis in determining occurrence of CECs in the environment.
    We acknowledge support from the National Science Foundation PIRE-HEARD award number 1545756 and USAID PEER subaward number 2000009924. S.S. thanks the National Science Foundation (Award #1904825) for support of this research, and the Donors of the American Chemical Society Petroleum Research Fund (PRF-58954-UNI5). We also thank Shyrill Mae Mariano from the Marine Science Institute in the University of the Philippines − Diliman who helped with the sample collection and Rebecca Dickman from University at Buffalo for her help on technical work.
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    Mining small molecules from Teredinibacter turnerae strains isolated from Philippine Teredinidae
    Villacorta, Jamaine B.; Rodriguez, Camille V.; Peran, Jacquelyn E.; Batucan, Jeremiah D.; Concepcion, Gisela; Salvador-Reyes, Lilibeth A.; Junio, Hiyas A. (MDPI, 2022-11-21)
    Endosymbiotic relationship has played a significant role in the evolution of marine species, allowing for the development of biochemical machinery for the synthesis of diverse metabolites. In this work, we explore the chemical space of exogenous compounds from shipworm endosymbionts using LC-MS-based metabolomics. Priority T. turnerae strains (1022X.S.1B.7A, 991H.S.0A.06B, 1675L.S.0A.01) that displayed antimicrobial activity, isolated from shipworms collected from several sites in the Philippines were cultured, and fractionated extracts were subjected for profiling using ultrahigh-performance liquid chromatography with high-resolution mass spectrometry quadrupole time-of-flight mass analyzer (UHPLC-HRMS QTOF). T. turnerae T7901 was used as a reference microorganism for dereplication analysis. Tandem MS data were analyzed through the Global Natural Products Social (GNPS) molecular networking, which resulted to 93 clusters with more than two nodes, leading to four putatively annotated clusters: lipids, lysophosphatidylethanolamines, cyclic dipeptides, and rhamnolipids. Additional clusters were also annotated through molecular networking with cross-reference to previous publications. Tartrolon D cluster with analogues, turnercyclamycins A and B; teredinibactin A, dechloroteredinibactin, and two other possible teredinibactin analogues; and oxylipin (E)-11-oxooctadec-12-enoic acid were putatively identified as described. Molecular networking also revealed two additional metabolite clusters, annotated as lyso-ornithine lipids and polyethers. Manual fragmentation analysis corroborated the putative identification generated from GNPS. However, some of the clusters remained unclassified due to the limited structural information on marine natural products in the public database. The result of this study, nonetheless, showed the diversity in the chemical space occupied by shipworm endosymbionts. This study also affirms the use of bioinformatics, molecular networking, and fragmentation mechanisms analysis as tools for the dereplication of high-throughput data to aid the prioritization of strains for further analysis.
    The research was completed under the supervision of the Department of Agriculture-Bureau of Fisheries and Aquatic Resources (DA-BFAR), Philippines in compliance with Prior Informed Consent (PIC) certificate requirements and all required legal instruments and regulatory issuances covering the conduct of the research. The authors would also like to acknowledge the Department of Science and Technology-funded Discovery and Development of Health Products Program (DOST-DDHP) for the LC-MS Facility of the Institute of Chemistry, University of the Philippines Diliman.
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    Synthesis and biological evaluation of cyanobacterial-inspired peptides
    Casanova, Jannelle R.; Villaraza, Aaron Joseph L.; Salvador-Reyes, Lilibeth (Philippine-American Academy of Science and Engineering, 2024-03-18)
    Cyanobacteria are known producers of structurally diverse and potent natural products; the majority are peptides with unique modifications. Yet, there remains a huge underexplored chemodiversity from cyanobacteria. Here, we designed a linear octapeptide as a product of combinatorial peptide design inspired by the natural products from the filamentous cyanobacteria Hapalosiphon welwitschii and Leptolyngbya sp. The target peptide was synthesized via solid-phase peptide synthesis (SPPS) using fluorenylmethyloxycarbonyl-protecting group (Fmoc) strategy. Structural diversity was expanded by the substitution of unnatural amino acids to yield five analogues. The structure and sequence of the synthesized peptides were confirmed using nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). Biological activity evaluation was done; with none of the peptides showing antimicrobial or cytotoxic activities against microbial pathogens and mammalian cells, respectively. To our knowledge, this study is the first to report a combinatorial peptide design inspired by a natural product and a predicted biosynthetic product. This strategy of peptide design expands the chemistry of a known bioactive natural product with the aid of unexplored cyanobacterial biosynthetic gene clusters.
    This study was funded by the Philippine Council for Health Research and Development – Department of Science and Technology through the Discovery and Development of Health Products – Marine Component Program. J.R.C acknowledges scholarship support from the Accelerated Science and Technology Human Resource Development Program of the Department of Science and Technology – Science Education Institute. We acknowledge the assistance of Z. Malto, J. Peran and S. Susana in the conduct of the biological assays. This is MSI Contribution No. 502.