Nocardiopsis alba is frequently isolated from environment and has recently been suggested as a casual symbiotic actinobacterium of diverse invertebrates. Using activity-guided fractionation, we purified two antibacterial cyclic dipeptides, cyclo(ΔPhe-ΔLeu) (albonoursin) and cyclo(ΔmTyr-ΔLeu), from a culture of Nocardiopsis alba ATCC BAA-2165. Analysis of N. alba genome revealed genetic information similar to albonoursin biosynthetic gene cluster, albABC. An albABC gene deletion mutant of N. alba was generated. Liquid chromatography-mass spectrometry analysis showed that the mutant could not produce the cyclic dipeptides. Cyclic dipeptide production in the mutant was restored by genetic complementation with the albABC cloned in a native plasmid of Nocardiopsis. β-Glucuronidase reporter assays with a second mutant construct, in which albABC promoter is transcriptionally fused to the reporting gene gusA, indicated that albABC gene expression was subject to osmoregulation. The system presented will be used to study the metabolic and genetic control of cyclic dipeptide biosynthesis in Nocardiopsis.
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Molecules
December 2024
College of Chemical and Biological Engineering, Shandong University of Science and Technology, Qingdao 266590, China.
Mar Drugs
December 2024
CAS Key Laboratory of Tropical Marine Bio-resources and Ecology/Guangdong Key Laboratory of Marine Materia Medica, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
Five new metabolites, including three cyclic dipeptide derivatives (-) and two new polyketides (-), together with nine known ones (- and -), were isolated from the mangrove-sediments-derived fungus sp. SCSIO 41431. Their structures were determined using detailed NMR, MS spectroscopic analyses, and quantum chemical calculations.
View Article and Find Full Text PDFJ Environ Sci Health B
January 2025
Department of Chemistry, B.M.S. College of Engineering, Bengaluru, Karnataka, India.
In this work, we fabricated the Fmoc-Pro-Phe-OMe modified carbon paste electrode (FPPO/MCPE) and used it for electrochemical detection of CP and FZ in a 0.1 M phosphate buffer solution (pH = 7). We characterized the Fmoc-Pro-Phe-OMe and applied it for the electrochemical detection of CP and FZ.
View Article and Find Full Text PDFChemphyschem
December 2024
Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India.
A new class of cyclic dipeptide-isatin hybrids was synthesized using 2,5-diketopiperazine and various isatin derivatives bearing flexible chains and extended aromatic rings in a double Knoevenagel condensation process. These new series demonstrate high solubility and good thermal stability with decomposition temperatures exceeding 370 °C, especially the molecular design with efficient space-filling (CI5 and CI6) stabilized columnar liquid crystalline phase. The hole and electron carrier mobility of the CI5 compound, measured using the space charge limited current (SCLC) technique, were found to be 9.
View Article and Find Full Text PDFBiofilm
December 2024
Department of Life Sciences, School of Natural Sciences, Shiv Nadar Institution of Eminence, Delhi NCR, Greater Noida, 201314, India.
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