Jiying Pei

Comparing ESI+ and ESI− in HPLC-Orbitrap-MS/MS analysis of SYBH DOM shows detection differences/correlations for compounds/parameters, emphasizing multi-mode ionization to avoid bias in marine DOM profiling.

Life-history strategies play a critical role in susceptibility to environmental stresses for Scleractinia coral. Metabolomics, which is capable of determining the metabolic responses of biological systems to genetic and environmental changes, is competent for the characterization of species’ biological traits. In this study, two coral species (Pocillopora meandrina and Seriatopora hystrix in the South China Sea) with different life-history strategies (“competitive” and “weedy”) were targeted, and untargeted mass spectrometry metabolomics combined with molecular networking was applied to characterize their differential metabolic pathways. The results show that lyso-platelet activating factors (lyso-PAFs), diacylglyceryl carboxyhydroxymethylcholine (DGCC), aromatic amino acids, and sulfhydryl compounds were more enriched in P. meandrina, whereas new phospholipids, dehydrated phosphoglycerol dihydroceramide (de-PG DHC), monoacylglycerol (MAG), fatty acids (FA) (C < 18), short peptides, and guanidine compounds were more enriched in S. hystrix. The metabolic pathways involved immune response, energy metabolism, cellular membrane structure regulation, oxidative stress system, secondary metabolite synthesis, etc. While the immune system (lysoPAF) and secondary metabolite synthesis (aromatic amino acids and sulfhydryl compounds) facilitates fast growth and resistance to environmental stressors of P. meandrina, the cell membrane structure (structural lipids), energy storage (storage lipids), oxidative stress system (short peptides), and secondary metabolite synthesis (guanidine compounds) are beneficial to the survival of S. hystrix in harsh conditions. This study contributes to the understanding of the potential molecular traits underlying life-history strategies of different coral species.

Life-history strategies play a critical role in susceptibility to environmental stresses for scleractinia coral. Metabolomics, which is regarded as the ultimate response of biological systems to genetic and environmental changes, is competent for the characterization of species’ biological traits. In this study, we combined untargeted mass spectrometry metabolomics and molecular networking to characterize the differential metabolic pathways between Pocillopora meandrina, one of the dominant species in South China Sea (SCS) with the life-history strategy of “competitive”, and Seriatopora hystrix, one of the nondominant species with the life-history strategy of “weedy” in SCS. The results show that lyso-PAF, DGCC, aromatic amino acids, and sulfhydryl compounds were more enriched in P. meandrina, whereas new phospholipid, de-PG DHC, MAG, FA (C<18), peptides, and guanidine compounds were more enriched in S. hystrix. The metabolic pathways involving immune response, energy metabolism, cellular membrane structure regulation, oxidative stress system, secondary metabolite synthesis, and et al. were speculated to relate to coral’s physiological traits, which finally resulted in the faster growth rate of P. meandrina and more robust environmental adaptability of S. hystrix. This study contributed to understanding of the potential molecular traits underlying life-history strategies of different coral species.

Combinatorial synthesis has been widely used as an efficient strategy to screen for active compounds. Mass spectrometry is the method of choice in the identification of hits resulting from high-throughput screenings due to its high sensitivity, specificity, and speed. However, manual data processing of mass spectrometry data, especially for structurally diverse products in combinatorial chemistry, is extremely time-consuming and one of the bottlenecks in this process. In this study, we demonstrated the effectiveness of a tandem mass spectrometry molecular networking-based strategy for product identification, reaction dynamics monitoring, and active compound targeting in combinatorial synthesis. Molecular networking connects compounds with similar tandem mass spectra into a cluster and has been widely used in natural products analysis. We show that both the expected and side products can be readily characterized using molecular networking based on their mass spectrometry fragmentation patterns. Additionally, time-dependent molecular networking was integrated to track reaction dynamics to determine the optimal reaction time to maximize target product yields. We also present a proof-of-concept experiment that successfully identified and isolated active molecules from a dynamic combinatorial library. These results demonstrated the potential of using molecular networking for identifying, tracking, and high-throughput screening of active compounds in combinatorial synthesis.