Chronic rhinosinusitis with nasal polyps (CRSwNP) is a persistent inflammation of the sinonasal mucosa. CRSwNP treatments are associated with inconsistent efficacy and recurrence of symptoms. Dynorphin 1-17 (DYN 1-17) and its fragments have been shown to modulate the immune response in various inflammatory conditions. This study aimed to investigate the effect of different pH and degrees of inflammation on DYN 1-17 metabolism in human CRSwNP tissues. DYN 1-17 was incubated with grade 3 and grade 4 inflamed tissues of CRSwNP patients at pH 5.5 and pH 7.4 over a range of incubation periods. The resulting fragments were identified using an ultra-performance liquid chromatography (UPLC) system coupled to quadrupole-time of flight (QTOF) mass spectrometry based on their accurate mass. The rate of DYN 1-17 fragmentation was slower at pH 5.5 in comparison to pH 7.4. The extent and rate of metabolism of DYN 1-17 were much lower in grade 3 inflamed tissue (31-32 fragments) than in grade 4 (34-41 fragments). N-Terminal fragments (DYN 1-15, 1-11, 1-10, and 1-6) were metabolized slower at pH 5.5 as compared to pH 7.4. DYN 1-12, 1-8, 2-10, 4-10, 5-10, and 8-14 were only observed under the inflammatory pH while DYN 5-17 and 6-17 were only identified upon incubation with grade 4 CRSwNP tissues. DYN 1-17 metabolism was significantly affected by the pH level and the severity of the inflammation of CRSwNP tissues, indicating the potential roles of DYN 1-17 and its fragments in modulating the inflammatory response and their avenue as therapeutics in future studies.
Harmful algal blooms in the benthic system (BHAB) are a major environmental problem that has increased worldwide in the context of global climate change. While systematic cell-based BHAB monitoring for risk assessment and early warning systems have been recommended, implementation of a standardized sampling method is challenging owing to the benthic nature of these harmful microalgal taxa. This study investigated the molecular diversity of benthic harmful dinoflagellates in tropical reefs of Perhentian Islands, Malaysia, using artificial substrate (AS) and sampling natural substrates (NS), combined with environmental DNA (eDNA) analysis and high-throughput amplicon sequencing targeting the small subunit (SSU) and large subunit (LSU) rDNA markers. Our results revealed that the AS method effectively captured a representative subset of the benthic dinoflagellate community, with significant taxonomic overlap between AS and NS. Both markers enabled high-resolution detection of BHAB taxa, particularly of Gambierdiscus and Ostreopsis, which are challenging to identify by light microscopy. The LSU rDNA marker provided finer taxonomic resolution, capturing a broader range of dinoflagellate species. The molecular approach consistently aligned with cell quantification data, supporting AS and DNA metabarcoding as robust methods for BHAB monitoring. The findings highlight the potential of these methods for early detection, especially areas susceptible for ciguatera and BHAB-related poisoning, offering a systematic approach for routine cell-based monitoring.
The dinoflagellate Tripos furca, known for its frequent and massive blooms in coastal waters, has been associated with significant fish mortality in aquaculture areas. In mid-May 2022, a notable bloom event, characterized by intense red discoloration, was observed along the Penang Strait in the northern Malacca Strait. Our field survey identified a high-density bloom of T. furca. To investigate the mechanisms driving the bloom dynamics of this species, monthly sampling was undertaken until the bloom subsided, covering 19 stations across the Penang Strait. Our results showed that the abundances of T. furca changed over time and space, a bloom peak of 8.2 × 105 cells l-1 was observed in late June, triggered by elevated sea surface temperatures and phosphate availability, while nitrogen was consistently abundant. The bloom's persistence was associated with the influence of the 2020-2022 La Niña and Indian Ocean Dipole, which caused warmer sea temperatures. Metabarcoding of the V7-V9 18S rDNA region revealed high intraspecific genetic diversity within the T. furca bloom subpopulations, suggesting both clonal reproduction and possible sexual processes. The bloom termination was linked to a seasonal shift in temperatures and changes in nutrient regimes that caused a transition of phytoplankton compositions to Noctiluca- and diatom-dominated populations contributed to the bloom's decline. Early detection of the bloom has successfully prevented severe losses to the aquaculture farms in the area, emphasizing the importance of early intervention. This study also enhances our understanding of T. furca bloom dynamics and provides insights into managing harmful algal blooms in tropical coastal regions.