bims-mricoa 2022-02-27 papers

Issue of 2022–02–27
two papers selected by
Merve Yavuz, Bilkent University

Curr Opin Biomed Eng. 2021 Dec;pii: 100330. [Epub ahead of print]20

Magnetic Iron Oxide Nanoparticles for Biomedical Applications.

Owing to the quantum confinement at the nanoscale, magnetic iron oxide nanoparticles (MIONs) consisting of magnetite and maghemite nanocrystals have unique physical properties, enabling a wide range of biomedical applications by utilizing mechanical, magnetic, chemical, and thermal effects of MIONs respectively. For example, MIONs can serve as a contrast agent for magnetic resonance imaging (MRI), convert electromagnetic energy into thermal energy for hyperthermia therapy, and carry drug/gene for targeted in vivo delivery. In this review, we discuss the recent development of MION based engineering approaches and their biomedical applications, including sensitive protein quantification, magnetic nanoparticle heating, in vivo molecular imaging, and drug delivery. The opportunities and challenges in further exploring the biomedical applications of MIONs are also briefly discussed.

Keywords: magnetic heating; magnetic iron oxide nanoparticles; molecular imaging; protein detection

DOI: https://doi.org/10.1016/j.cobme.2021.100330

Nature. 2022 Feb 23.

The bacterial toxin colibactin triggers prophage induction.

Justin E Silpe, Joel W H Wong, Siân V Owen, Michael Baym, Emily P Balskus.

Colibactin is a chemically unstable small-molecule genotoxin that is produced by several different bacteria, including members of the human gut microbiome1,2. Although the biological activity of colibactin has been extensively investigated in mammalian systems3, little is known about its effects on other microorganisms. Here we show that colibactin targets bacteria that contain prophages, and induces lytic development through the bacterial SOS response. DNA, added exogenously, protects bacteria from colibactin, as does expressing a colibactin resistance protein (ClbS) in non-colibactin-producing cells. The prophage-inducing effects that we observe apply broadly across different phage-bacteria systems and in complex communities. Finally, we identify bacteria that have colibactin resistance genes but lack colibactin biosynthetic genes. Many of these bacteria are infected with predicted prophages, and we show that the expression of their ClbS homologues provides immunity from colibactin-triggered induction. Our study reveals a mechanism by which colibactin production could affect microbiomes and highlights a role for microbial natural products in influencing population-level events such as phage outbreaks.

DOI: https://doi.org/10.1038/s41586-022-04444-3