INFORM October 2024

inform October 2024, Vol. 35 (9) • 31

antibiotics trap a substrate-bound conformation of the LPS transporter that stalls this machine. The inhibitors accomplish this by recognizing a composite binding site made up of both the Lpt transporter and its LPS substrate. Collectively, our findings identify an unusual mecha nism of lipid transport inhibition, reveal a druggable conformation of the Lpt transporter and provide the foundation for extending this class of antibiotics to other Gram-negative pathogens.

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Ignacio Vieitez is a research professor at the Universdad de la República in Montevideo, Uruguay. He studies green extraction processes to isolate bioactive compounds and determines their potential benefits as food ingredients.

Real-time biosynthetic reaction monitoring informs the mechanism of action of antibiotics Oluwole, A. O., et al. , Journal of the American Chemical Society , 146, 10, 2024. https://doi.org/10.1021/jacs.4c00081 The rapid spread of drug-resistant pathogens and the declining discovery of new antibiotics have created a global health crisis and heightened interest in the search for novel antibiotics. Beyond their discovery, elucidating mechanisms of action has necessitated new approaches, especially for antibiotics that interact with lipidic sub strates and membrane proteins. Here, we develop a methodology for real-time reaction monitoring of the activities of two bacterial membrane phosphatases, UppP and PgpB. We then show how we can inhibit their activities using existing and newly discovered anti biotics such as bacitracin and teixobactin. Additionally, we found that the UppP dimer is stabilized by phosphatidylethanolamine, which, unexpectedly, enhanced the speed of substrate process ing. Overall, our results demonstrate the potential of native mass spectrometry for real-time biosynthetic reaction monitoring of membrane enzymes, as well as their in-situ inhibition and cofactor binding, to inform the mode of action of emerging antibiotics. intermembrane transporter Pahil, K. S., et al. , Nature , 625, 572-577, 2024. https://doi.org/10.1038/s41586-023-06799-7 Gram-negative bacteria are extraordinarily difficult to kill because their cytoplasmic membrane is surrounded by an outer membrane that blocks the entry of most antibiotics. The impenetra ble nature of the outer membrane is due to the presence of a large, amphipathic glycolipid called lipopolysaccharide (LPS) in its outer leaflet. Assembly of the outer membrane requires transport of LPS across a protein bridge that spans from the cytoplasmic membrane to the cell surface. Maintaining outer membrane integrity is essential for bacterial cell viability, and its disruption can increase susceptibil ity to other antibiotics. Thus, inhibitors of the seven lipopolysaccha ride transport (Lpt) proteins that form this transenvelope transporter have long been sought. A new class of antibiotics that targets the LPS transport machine in Acinetobacter was recently identified. Here, using structural, biochemical and genetic approaches, we show that these A new antibiotic traps lipopolysaccharide in its

Oleosomes are natural oil droplets, present in all organisms and abun dant in oilseeds. After their aqueous extraction from oilseeds, they can be directly utilized as oil droplets in food, cosmetics and all types of oil in-water emulsion systems. Oleosomes are particles equipped with a membrane, comprising a continuous monolayer of phospholipids and hydrophobic proteins, which covers the triglyceride core and grants them extreme physical and chemical stability. The significant proper ties of oleosomes, such as their high emulsifying capacity, low toxicity potential, biocompatibility, and cost-effectiveness, have garnered sig nificant attention in the context of their application as natural emul sifiers. These selected articles highlight some particularly interesting examples about oleosomes applications. Recent trends in oleosomes: Extraction methods, structural characterization, and novel applications Shi, Z., et al. , Trends in Food Science & Technology , 151, 104621, 2024. https://doi.org/10.1016/j.tifs.2024.104621 Background Oleosomes are nutrient-rich pure natural compounds that exist as oil-in-water (O/W) emulsions and have the advantage of nonemul sification. However, in the past few years, the development of oleo some extraction has been slow, and the understanding of oleosome composition, stability, and interfacial behavior has not been com prehensive enough. Therefore, there is a need for a critical and theo retical review of oleosomes. Scope and approach This paper proposes new insights into the structure, composition, and extraction method of natural oleosomes; discusses the factors influencing the stability, additional protective mechanisms, and interfacial behavior of oleosomes; and summarizes the potential application directions of oleosomes in the food industry. Key findings and conclusions In the future, the oleosomes extraction could adopt a combination of multiple assist-extraction to replace existing extraction methods, and