• Coprinuslactone protects the edible mushroom Coprinus comatus against biofilm infections by blocking both quorum-sensing and MurA.

      de Carvalho, Maira P; Gulotta, Giuseppe; do Amaral, Matheus W; Lünsdorf, Heinrich; Sasse, Florenz; Abraham, Wolf-Rainer; Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany. (2016-10-03)
      Pathogens embedded in biofilms are involved in many infections and are very difficult to treat with antibiotics because of higher resistance compared to planktonic cells. Therefore, new approaches for their control are urgently needed. One way to search for biofilm dispersing compounds is to look at defense strategies of organisms exposed to wet environments, which makes them prone to biofilm infections. It is reasonable to assume that mushrooms have developed mechanisms to control biofilms on their sporocarps (fruiting bodies). A preliminary screening for biofilms on sporocarps revealed several species with few or no bacteria on their sporocarps. From the edible mushroom Coprinus comatus where no bacteria on the sporocarp could be detected (3R,4S)-2-methylene-3,4-dihydroxypentanoic acid 1,4-lactone, named coprinuslactone, was isolated. Coprinuslactone interfered with quorum-sensing and dispersed biofilms of Pseudomonas aeruginosa, where it also reduced the formation of the pathogenicity factors pyocyanin and rhamnolipid B. Coprinuslactone also damaged Staphylococcus aureus cells in biofilms at subtoxic concentrations. Furthermore, it inhibited UDP-N-acetylglucosamine enolpyruvyl transferase (MurA), essential for bacterial cell wall synthesis. These two modes of action ensure the inhibition of a broad spectrum of pathogens on the fruiting body but may also be useful for future clinical applications. This article is protected by copyright. All rights reserved.
    • A role for PchHI as the ABC transporter in iron acquisition by the siderophore pyochelin in Pseudomonas aeruginosa.

      Roche, Béatrice; Garcia-Rivera, Mariel A; Normant, Vincent; Kuhn, Lauriane; Hammann, Philippe; Brönstrup, Mark; Mislin, Gaëtan L A; Schalk, Isabelle J; HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany. (John Wiley & Sons LTD, 2021-10-18)
      Iron is an essential nutrient for bacterial growth but poorly bioavailable. Bacteria scavenge ferric iron by synthesizing and secreting siderophores, small compounds with a high affinity for iron. Pyochelin (PCH) is one of the two siderophores produced by the opportunistic pathogen Pseudomonas aeruginosa. After capturing a ferric iron molecule, PCH-Fe is imported back into bacteria first by the outer membrane transporter FptA and then by the inner membrane permease FptX. Here, using molecular biology, 55 Fe uptake assays, and LC-MS/MS quantification, we first find a role for PchHI as the heterodimeric ABC transporter involved in the siderophore-free iron uptake into the bacterial cytoplasm. We also provide the first evidence that PCH is able to reach the bacterial periplasm and cytoplasm when both FptA and FptX are expressed. Finally, we detected an interaction between PchH and FptX, linking the ABC transporter PchHI with the inner permease FptX in the PCH-Fe uptake pathway. These results pave the way for a better understanding of the PCH siderophore pathway, giving future directions to tackle P. aeruginosa infections.