Bacteria can be refractory to antibiotics due to a sub-population of dormant cells, called persisters that are highly tolerant to antibiotic exposure. The low frequency and transience of the antibiotic tolerant “persister” trait has complicated elucidation of the mechanism that controls antibiotic tolerance. In this study, we show that 2’ Amino-acetophenone (2-AA), a poorly studied but diagnostically important small, volatile molecule produced by the recalcitrant gram-negative human pathogen Pseudomonas aeruginosa, promotes antibiotic tolerance in response to quorum-sensing (QS) signaling. Our results show that 2-AA mediated persister cell accumulation occurs via alteration of the expression of genes involved in the translational capacity of the cell, including almost all ribosomal protein genes and other translation-related factors. That 2-AA promotes persisters formation also in other emerging multi-drug resistant pathogens, including the non 2-AA producer Acinetobacter baumannii implies that 2-AA may play an important role in the ability of gram-negative bacteria to tolerate antibiotic treatments in polymicrobial infections. Given that the synthesis, excretion and uptake of QS small molecules is a common hallmark of prokaryotes, together with the fact that the translational machinery is highly conserved, we posit that modulation of the translational capacity of the cell via QS molecules, may be a general, widely distributed mechanism that promotes antibiotic tolerance among prokaryotes.

Sea buckthorn berries (Hippophaë rhamnoides L.) (SB) are considered as a fruit with a high nutritional value with a plethora of bioactive ingredients. The present work focusses on the analysis of the whole NMR metabolic profile of SB berries grown in an organic orchard of Meteora/Greece. In parallel, this study validates/highlights qualitative characteristics of the osmotic processed berries according to the fresh fruit. The composition in bioactive metabolites of SB berries was elucidated through sophisticated high-resolution NMR spectroscopy. The lipophilic profile maintains the vitamins, flavonoid glycosides, phenolic esters and the essential lipid components of SB, while the polar profile reveals a variety of flavonoids, saccharides, organic acids, amino acids and esterified glycosides. This approach towards identification of SB bioactive ingredients may serve as basis for simultaneous profiling and quality assessment and may be applied to monitor fresh food quality regarding other food preservation methods.

Scope Sea buckthorn (Hippophaes rhamnoides) is capable of ameliorating disturbed glucose metabolism in animal models and human subjects. Here, the effect of sea buckthorn oil as well as of extracts of fruits, leaves, and press cake on postprandial glucose metabolism is systematically investigated. Methods and results Sea buckthorn did neither exert decisive effects in an in vitro model of intestinal glucose absorption nor did it alter insulin secretion. However, sea buckthorn stimulates GLUT4 translocation to the plasma membrane comparable to insulin, indicative of increased glucose clearance from the circulation. Isorhamnetin is identified in all sea buckthorn samples investigated and is biologically active in triggering GLUT4 cell surface localization. Consistently, sea buckthorn products lower circulating glucose by ≈10% in a chick embryo model. Moreover, sea buckthorn products fully revert hyperglycemia in the nematode Caenorhabditis elegans while they are ineffective in Drosophila melanogaster under euglycemic conditions. Conclusion These data indicate that edible sea buckthorn products as well as by‐products are promising resources for hypoglycemic nutrient supplements that increase cellular glucose clearance into target tissues.