Localization of an IgE epitope of glycinin A2 peptide chain.

INTRODUCTION: One of the main allergens in soybeans is glycinin, which seriously impacts the normal lives of allergic people. Previous studies have confirmed that thermal processing and thermal processing combined with ultrahigh-pressure processing could significantly reduce the antigenicity of glycinin. The dominant antigen region of acidic peptide chain A2 of G2 subunit was located by phage display experiment. METHODS: In this paper, overlapping peptides and alanine substitution techniques were used to explore the key amino acids that significantly affect the antigenicity of A2 peptide chain. The purity of peptide 1, peptide 2 and peptide 3 was identified by mass spectrometry and high-performance liquid chromatography, and the results showed that the purity of the synthesized overlapping peptide was more than 90%. SDS-PAGE showed that the peptide was successfully coupled with bovine serum albumin. The antigenicity of the coupling peptide was tested by ELISA and Dot-Blot, and the allergenicity was detected by reacting with the serum of patients with soybean globulin allergy. CONCLUSION: The results showed that peptide 3 has stronger antigenicity and sensitization. Alanine substitution technology allowed one to perform site-directed mutagenesis on peptide 3. Dot-Blot and ELISA tests showed that D259, E260, E261, Q263 and C266 may be the key amino acids that significantly affect the antigenicity of peptide 3. The research presented is of great significance for correctly guiding the production of safe food and preventing the occurrence of food allergic diseases. © 2023 Society of Chemical Industry.

Spatiotemporal genetic structure of regional-scale Alexandrium catenella dinoflagellate blooms explained by extensive dispersal and environmental selection.

Paralytic Shellfish Poisoning (PSP) caused by the dinoflagellate Alexandrium catenella is a well-known global syndrome that negatively impacts human health and fishery economies. Understanding the population dynamics and ecology of this species is thus important for identifying determinants of blooms and associated PSP toxicity. Given reports of extensive genetic heterogeneity in the toxicity and physiology of Alexandrium species, knowledge of genetic population structure in harmful algal species such as A. catenella can also facilitate the understanding of toxic bloom development and ecological adaptation. In this study we employed microsatellite markers to analyze multiple A. catenella strains isolated from several sub-regions in the Gulf of Maine (GoM) during summer blooms, to gain insights into the sources and dynamics of this economically important phytoplankton species. At least three genetically distinct clusters of A. catenella were identified in the GoM. Each cluster contained representatives from different sub-regions, highlighting the extent of connectivity and dispersal throughout the region. This shared diversity could result from cyst beds created by previous coastal blooms, thereby preserving the overall diversity of the regional A. catenella population. Rapid spatiotemporal genetic differentiation of A. catenella populations was observed in local blooms, likely driven by natural selection through environmental conditions such as silicate and nitrate/nitrite concentrations, emphasizing the role of short-term water mass intrusions and biotic processes in determining the diversity and dynamics of marine phytoplankton populations. Given the wide-spread intraspecific diversity of A. catenella in GoM and potentially elsewhere, harmful algal blooms will likely persist in many regions despite global warming and changing environmental conditions in the future. Selection of different genetic lineages through variable hydrological conditions might impact toxin production and profiles of future blooms, challenging HAB control and prediction of PSP risk in the future.