Metallic radionuclides conjugated to biological vectors via an appropriate chelator are employed in nuclear medicine for the diagnosis (imaging) and radiotherapy of diseases. For the application of radiolabeled antibodies using positron emission tomography (immunoPET), zirconium-89 has gained increasing interest over the last decades as its physical properties (t_1/2 = 78.4 h, 22.6% β⁺ decay) match well with the slow pharmacokinetics of antibodies (t_biol. = days to weeks) allowing for late time point imaging. The most commonly used chelator for ⁸⁹Zr in this context is desferrioxamine (DFO). However, it has been shown in preclinical studies that the hexadentate DFO ligand does not provide ⁸⁹Zr-complexes of sufficient stability in vivo and unspecific uptake of the osteophilic radiometal in bones is observed. For clinical applications, this might be of concern not only because of an unnecessary dose to the patient but also an increased background signal. As a consequence, next generation chelators based on hydroxamate scaffolds for more stable coordination of ⁸⁹Zr have been developed by different research groups. In this review, we describe the progress in this research field until end of 2020, including promising examples of new candidates of chelators currently in advanced stages for clinical translation that outrun the performance of the current gold standard DFO.

The application of genomic techniques to the investigation of understudied species of actinobacteria provides an expedited route to the discovery of new bioactive natural products. We report the isolation of the antibiotic polyketide tatiomicin, through a genomics and bioactivity informed analysis of the metabolome of the extremophile Amycolatopsis sp. DEM30355. Structural elucidation including absolute stereochemical assignment was performed using complementary crystallographic, spectroscopic and computational methods. Tatiomicin shows antibiotic activity against Gram-positive bacteria, including Methicillin-resistant Staphylococcus aureus (MRSA).