Microalgae and cyanobacteria are good sources for prospecting metabolites of biotechnological interest, including glucosidase inhibitors. These inhibitors act on enzymes related to various biochemical processes; they are involved in metabolic diseases, such as diabetes and Gaucher disease, tumors and viral infections, thus, they are interesting hubs for the development of new drugs and therapies. In this work, the screening of 63 environmental samples collected in the Brazilian Amazon found activity against β-glucosidase, of at least 60 min, in 13.85% of the tested extracts, with Synechococcus sp. GFB01 showing inhibitory activity of 90.2% for α-glucosidase and 96.9% against β-glucosidase. It was found that the nutritional limitation due to a reduction in the concentration of sodium nitrate, despite not being sufficient to cause changes in cell growth and photosynthetic apparatus, resulted in reduced production of α and β-glucosidase inhibitors and differential protein expression. The proteomic analysis of cyanobacteria isolated from the Amazon is unprecedented, with this being the first work to evaluate the protein expression of Synechococcus sp. GFB01 subjected to nutritional stress. This evaluation helps to better understand the metabolic responses of this organism, especially related to the production of inhibitors, adding knowledge to the industrial potential of these cyanobacterial compounds.

Fruit ripening involves coordinated metabolic and molecular changes that shape quality traits, yet tissue-specific regulation in Selenicereus megalanthus remains unclear. Fruit development in S. megalanthus was investigated through an integrated analysis of pulp and peel across five developmental stages to elucidate tissue-specific metabolic and molecular regulatory dynamics. Proteomic profiling combined with targeted metabolomic analyses of sugars and phenolic compounds, multivariate statistics, and protein–protein interaction analysis was applied. A total of 411 proteins were identified in the pulp and 812 in the peel, of which 255 and 362 proteins, respectively, showed significant differential accumulation across development (p < 0.05), indicating higher regulatory plasticity in the peel. Multivariate analyses revealed clear stage-dependent reorganization of the proteome in both tissues. Functional annotation highlighted coordinated modulation of pathways related to cell wall remodeling, carbohydrate metabolism, antioxidant and detoxification systems, protein folding, and myo-inositol biosynthesis, directly associated with fruit texture and quality attributes. Metabolomic analyses revealed progressive sugar accumulation during ripening, with sucrose predominating at advanced stages, and pronounced tissue- and stage-dependent modulation of phenolic compounds, characterized by early enrichment in the pulp and sustained accumulation in the peel. Overall, these results demonstrate that yellow pitaya development involves tightly coordinated biochemical and regulatory mechanisms and identify the peel as a metabolically active tissue with relevance for postharvest management, fruit quality, and sustainable horticultural valorization.