menu.header.image.unacom.logo
 

National Committee on Marine Sciences (NCMS)

Permanent URI for this communityhttps://repository.unesco.gov.ph/handle/123456789/6

Browse

Filters

2023 - 202421

Settings

Start date: 2023Ocean Decade Challenge: search.filters.odc.Challenge 9: Skills, knowledge, and technology for all

Search Results

Now showing 1 - 10 of 21
  • Thumbnail Image
    Modified oxylipins as inhibitors of biofilm formation in Staphylococcus epidermidis
    Peran, Jacquelyn E.; Salvador-Reyes, Lilibeth A. (Frontiers Media SA, 2024-05-23)
    New approaches to combating microbial drug resistance are being sought, with the discovery of biofilm inhibitors considered as alternative arsenal for treating infections. Natural products have been at the forefront of antimicrobial discovery and serve as inspiration for the design of new antibiotics. We probed the potency, selectivity, and mechanism of anti-biofilm activity of modified oxylipins inspired by the marine natural product turneroic acid. Structure-activity relationship (SAR) evaluation revealed the importance of the trans-epoxide moiety, regardless of the position, for inhibiting biofilm formation. trans-12,13-epoxyoctadecanoic acid (1) and trans-9,10 epoxyoctadecanoic acid (4) selectively target the early stage of biofilm formation, with no effect on planktonic cells. These compounds interrupt the formation of a protective polysaccharide barrier by significantly upregulating the ica operon’s transcriptional repressor. This was corroborated by docking experiment with SarA and scanning electron micrographs showing reduced biofilm aggregates and the absence of thread-like structures of extrapolymeric substances. In silico evaluation revealed that 1 and 4 can interfere with the AgrA-mediated communication language in Staphylococci, typical to the diffusible signal factor (DSF) capacity of lipophilic chains.
  • No Thumbnail Available
    Contrasting reproductive strategies between stress-tolerant and competitive coral taxa
    Bonilla, K. G.; Guest, J. R.; Baria-Rodriguez, M. V. (Springer, 2023-04-19)
    Reproductive traits such as fecundity (i.e., the number of gametes produced) and the size and age of coral colonies at reproductive onset can vary in predictable ways among life history strategies. However, most studies on the onset of reproductive maturity in corals only report the presence or absence of oocytes with little known about variation in fecundity across size and age classes. This study aimed to determine the colony size and fecundity at the onset of reproductive maturity across size classes of two scleractinian corals with contrasting life history strategies, Acropora millepora (competitive) and Favites colemani (stress-tolerant). Colonies at a site in northwestern Philippines were sampled to determine the smallest colony size class with mature oocytes and to estimate fecundity across size classes. Histological slides were also prepared to verify the presence of mature gametes. Colonies were able to produce mature oocytes when they had attained colony diameters of 4.7 cm for A. millepora and 1.5 cm for F. colemani. A. millepora had lower fecundity, but larger oocytes compared to F. colemani. Although small colonies can contribute to the larval pool, the proportion of mature colonies increased for larger size classes, suggesting that larger colonies make a disproportionately greater contribution to population reproductive output. These findings contribute to our understanding of coral population dynamics, particularly in parameterizing population and demographic models for different coral life histories.
    We are grateful to Christine Baran, Jue Alef Lalas, Jerry Arboleda, Gabriel de Guzman, the students and research assistants of Community and Ecology and Interactions of Marine Bionts and Benthic Ecosystems Laboratories for their valuable assistance during field and laboratory works, Darryl Valino for the site map, and Liam Lachs for the assistance on the statistical analyses. This research was supported by the University of the Philippines Marine Science Institute’s In-house project, Department of Science and Technology – ASTHRDP Thesis Grant, and University of the Philippines – Office of the Vice President for Academic Affairs’ Balik Ph.D. project (OVPAA-BPhD-2018-02).
  • Thumbnail Image
    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.
  • No Thumbnail Available
    Ontogenetic variability in the diel activity pattern of the marine gastropod Cassis cornuta(Mollusca: Cassidae)
    Calle, Lala Grace; Cabaitan, Patrick C; Sayco, Sherry Lyn G; Tan, Shau Hwai; Conaco, Cecilia (Oxford University Press, 2024-01-25)
    Examining activity patterns is essential in understanding gastropod feeding and movement ecology. However, the diel activity patterns of large-bodied gastropods, such as Cassis cornuta, remain poorly studied. Here, we conducted outdoor hatchery-based experiments to examine the diel activity patterns of C. cornuta adults and juveniles under natural sunlight and photoperiod. Activities of C. cornuta, such as crawling, hunting, feeding, burrowing and resting on the substratum, were examined every hour for 3 days. Although most individuals were inactive for a greater part of the observation period, active behaviours were recorded for some individuals during both daytime and nighttime, suggesting that C. cornuta is cathemeral, as supported by a nonsignificant result from a Rayleigh's test of uniformity. A higher proportion of adult and juvenile C. cornuta were inactive, either burrowed or resting on the substratum, during the 24-h period. Peak activity time for juveniles started at 20:00, with up to 50% of individuals active, while peak activity time for adults started at 21:00, with up to 20% of active individuals. Adults spent more time resting aboveground, whereas juveniles spent more time burrowed under the sand when not feeding. Juveniles hunted more frequently and spent more time feeding compared to adults. Additionally, juveniles crawled faster and were more successful in capturing sea urchins than adults. The information on variability in the diel activity patterns and movement rates between adult and juvenile C. cornuta would allow further demographic studies, and provide insights into possible conservation strategies for this species.
  • No Thumbnail Available
    Genetic connectivity and diversity between tropical and subtropical populations of the tropical horned sea star Protoreaster nodosus in the northwest Pacific
    Nakajima, Yuichi; Yasuda, Nina; Matsuki, Yu; Arriesgado, Dan M.; Fortes, Miguel D.; Uy, Wilfredo H.; Campos, Wilfredo L.; Nadaoka, Kazuo; Lian, Chunlan (Springer, 2024-06-01)
    Seagrass beds are ecologically and economically important coastal ecosystems, and seagrass-associated organisms are a key part of their biodiversity. Marine organisms that reproduce through broadcast spawning are likely to have less genetic differentiation among populations than those that use other modes of reproduction, but this has not been well studied. Here, we investigated the genetic diversity, genetic differentiation, and migration patterns of the seagrass-associated sea star Protoreaster nodosus across 12 sites spanning approximately 2500 km from the Ryukyu Archipelago, Japan, to the Philippines. We genotyped 405 individuals by using seven microsatellite loci and analyzed allelic richness and expected heterozygosity as indices of genetic diversity. Of these two indices, only expected heterozygosity decreased slightly with increasing latitude. These results suggest that genetic diversity has not clearly decreased, even in the isolated Ryukyu Archipelago populations. Geographic distance was significantly correlated with genetic differentiation (pairwise FST: − 0.005 to 0.049). However, populations in the Ryukyu Archipelago and the Philippines showed relatively low genetic structuring and the pairwise genetic differentiation between these regions was often non-significant. Analysis of historical migration rates showed bidirectional north–south migration, which appears to be influenced by the Kuroshio Current and its countercurrents.
    We thank members of the project ‘Coastal Ecosystem Conservation and Adaptive Management under Local and Global Environmental Impacts in the Philippines’ (CECAM project: https://sites.google.com/view/cecam-project).
  • Thumbnail Image
    Decadal stability in coral cover could mask hidden changes on reefs in the East Asian Seas
    Chan, Y. K. S.; Affendi, Y. A.; Ang, P. O.; Baria-Rodriguez, M. V.; Chen, C. A.; Chui, A. P. Y.; Glue, M.; Huang, H.; Kuo, C-Y.; Kim, S. W.; Lam, V. Y. Y.; Lane, D. J. W.; Lian, J. S.; Lin, S. M. N. N.; Lunn, Z.; Nañola, C. L.; Nguyen, V. L.; Park, H. S.; Sutthacheep, M.; Vo, S. T.; Vibol, O.; Waheed, Z.; Yamano, H.; Yeemin, T.; Yong, E.; Kimura, T.; Tun, K.; Chou, L. M.; Huang, D. (Springer, 2023-06-10)
    Coral reefs in the Central Indo-Pacific region comprise some of the most diverse and yet threatened marine habitats. While reef monitoring has grown throughout the region in recent years, studies of coral reef benthic cover remain limited in spatial and temporal scales. Here, we analysed 24,365 reef surveys performed over 37 years at 1972 sites throughout East Asia by the Global Coral Reef Monitoring Network using Bayesian approaches. Our results show that overall coral cover at surveyed reefs has not declined as suggested in previous studies and compared to reef regions like the Caribbean. Concurrently, macroalgal cover has not increased, with no indications of phase shifts from coral to macroalgal dominance on reefs. Yet, models incorporating socio-economic and environmental variables reveal negative associations of coral cover with coastal urbanisation and sea surface temperature. The diversity of reef assemblages may have mitigated cover declines thus far, but climate change could threaten reef resilience. We recommend prioritisation of regionally coordinated, locally collaborative long-term studies for better contextualisation of monitoring data and analyses, which are essential for achieving reef conservation goals.
  • No Thumbnail Available
    Hydrodynamics rather than type of coastline shapes self‐recruitment in anemonefishes
    Sato, Masaaki; Honda, Kentaro; Nakamura, Yohei; Bernardo, Lawrence Patrick C.; Bolisay, Klenthon O.; Yamamoto, Takahiro; Herrera, Eugene C.; Nakajima, Yuichi; Lian, Chunlan; Uy, Wilfredo H.; Fortes, Miguel D.; Nadaoka, Kazuo; Nakaoka, Masahiro (Wiley, 2023-07-25)
    Many marine species have a pelagic larval phase that undergo dispersal among habitats. Studies on marine larval dispersal have revealed a large variation in the spatial scale of dispersal and self-recruitment. However, few studies have investigated the influence of types of coastline (e.g., bay vs. open coast) on marine larval dispersal. Bays or lagoons generally enhance the retention of larvae, while larvae are more likely to be flushed by strong currents in open coasts. To examine associations between larval dispersal, coastline type, and hydrodynamics, we compared fin-scale dispersal patterns, self-recruitment, and local retention (LR) of two anemonefishes (Amphiprion frenatus and Amphiprion perideraion) between a semi-enclosed bay and an open coast in the Philippines combining genetic parentage analysis and biophysical dispersal modeling. Contrary to our expectations, parentage analysis revealed lower estimates of self-recruitment in the semi-closed bay (0%) than in the open coast (14–15%). The result was consistent with dispersal simulations predicting lower LR and self-recruitment in the semi-closed bay (0.4% and 19%) compared to the open coast (2.9% and 38%). Dispersal modeling also showed that cross-shore currents toward offshore were much stronger around the semi-closed bay and were negatively correlated with LR and self-recruitment. These results suggest that stronger cross-shore currents around the semi-closed bay transport anemonefish larvae to the offshore and mainly contributed to the lower self-recruitment. Our results highlight importance of hydrodynamics on larval dispersal and difficulty in predicting self-recruitment from coastline type alone.
  • No Thumbnail Available
    Fisheries Administrative Order No. 268: Series of 2023. Rules and regulations governing the catch certification or documentation scheme for fish and fishery products intended for export that require catch certificates.
    (Department of Agriculture, 2023-01-16)
    This Regulation aims to ensure traceability of fishery products obtained from legal means in all stages of supply chain, establish a harmonized mandatory procedures on catch certification for export of fishery products, ensure compliance with applicable domestic laws, and update and revise the procedures on catch certifications scheme, and to ensure continued global market access of Philippine fish and fishery products. The text further provides for regular catch certificate, processing statement and non-processing statement, simplified catch certificate, record-keeping, monitoring and payment of fees, and settlement of issues. This Order shall apply to all foreign or Philippine-flagged fishing vessels that supply raw materials to canneries, processors or exporters for processing prior to the export of the processed fishery products. The text contains 30 Articles and has 12 Annexes.
  • No Thumbnail Available
    Total polyphenol content of tropical marine and coastal flora: Potentials for food and nutraceutical applications
    Narvarte, Bienson Ceasar V.; Genovia, Tom Gerald T.; Hinaloc, Lourie Ann R.; Gonzaga, Shienna Mae C.; Tabonda-Nabor, April Mae; Palecpec, Flora Maye R.; Dayao, Helen M.; Roleda, Michael Y. (Springer, 2023-07-08)
    The marine environment is abundant in natural products that are beneficial to humans. Among these compounds are the polyphenols produced by marine flora as secondary metabolites and used as a defense against stressful environmental conditions. Accordingly, recent pharmacological and biomedical studies showed that polyphenols from marine and coastal floras have several important bioactivities including antioxidant property. In this study, we measured the total polyphenol content (TPC) of 75 species of marine-associated flora. The TPC of their methanolic extracts was measured spectrophotometrically using the Folin-Ciocalteu assay and was expressed both as mg phloroglucinol equivalent per g of dry weight (mg PGE g−1 DW) and as mg gallic acid equivalent per g dry weight (mg GAE g−1 DW). The TPC values are higher when expressed in terms of GAE compared to PGE. Also, the mean TPC of tracheopytes (229 ± 43.0 mg PGE g−1 DW) was higher compared to the mean TPC of macroalgae (69.4 ± 9.59 mg PGE g−1 DW). For macroalgae, ochrophytes (97.9 ± 22.7 mg PGE g−1 DW) had the highest mean TPC followed by chlorophytes (80.0 ± 20.5 mg PGE g−1 DW) and rhodophytes (49.5 ± 8.60 mg PGE g−1 DW). Moreover, our study also showed that TPC varied between young and mature tissues, among different color morphotypes and different parts of the plants. Although the concentrations of total polyphenols varied among species, ages, strains and parts of the plant, our study showed that marine and coastal floras are rich sources of polyphenols that could be further examined for their biological activities and other applications in food industry.
  • Thumbnail Image
    Genomics and metabolomics-based assessment of the biosynthetic potential of the sponge-associated microorganism Streptomyces cacaoi strain R2A-843A from the Philippines
    Malto, Zabrina Bernice L.; Reyes, Joeriggo M.; Lo, Bernard Isaiah; Davis, Kevin Bossie S.; Concepcion, Gisela; Salvador-Reyes, Lilibeth A. (Philippine-American Academy of Science and Engineering, 2023-10-20)
    The biosynthetic machinery of the sponge-associated Streptomyces cacaoi strain R2A-843A was assessed using a combined genomics and metabolomics approach. Whole genome sequencing and molecular networking showed the high biosynthetic potential of this actinomycete. A significant proportion of the genome is dedicated to secondary metabolite production, with biosynthetic gene clusters for nonribosomal peptides, polyketides, and terpenes being the most represented. Seven cyclic pentapeptides, including a putative new analogue, and a glycosylated lanthipeptide were identified using HRMS and untargeted MS/MS analysis. To validate our genome and metabolome analysis, we undertook a mass spectrometry-guided purification and confirmed the production of the known peptides BE-18257A (1) and BE-18257B (2). The production of 1 and 2 and the growth of the microorganism were monitored for eight days. Compound 2 was produced at a higher concentration, starting at 48 h post-incubation. Both compounds were noncytotoxic against colorectal and breast cancer cell lines.
    The authors acknowledge funding support from the Department of Science and Technology - Philippine Council for Health Research and Development through the Discovery and Development of Health Products - Marine Component Program. Genome sequencing was made possible through the CHEDPCARI IHITM63 Project. We thank Ms. Shalice R. SusanaGuevarra for conducting the bioactivity assay. This work was done under the supervision of the Bureau of Fisheries and Aquatic Resources under Gratuitous Permit No. FBP-0035-10. This is MSI Contribution No. 501.