Measuring Bacterial Flagellar Motor Dynamics via a Bead Assay.

The bacterial flagellar motor (BFM) is a rotary molecular machine that drives critical bacterial processes including motility, chemotaxis, biofilm formation, and infection. For over two decades, the bead assay, which measures the rotation of a microparticle attached to the flagellum of a surface-attached bacterium, has been instrumental in deciphering the motor's biophysical mechanisms. This technique has not only quantified the rotational speed and frequency of directional switching as a function of the viscous load on the flagellum but has also revealed the BFM's capacity for mechanosensitive speed modulation, adapting to environmental conditions.

Molecular model of a bacterial flagellar motor reveals a "parts-list" of protein adaptations to increase torque.

One hurdle to understanding how molecular machines work, and how they evolve, is our inability to see their structures . Here we describe a minicell system that enables cryogenic electron microscopy imaging and single particle analysis to investigate the structure of an iconic molecular machine, the bacterial flagellar motor, which spins a helical propeller for propulsion. We determine the structure of the high-torque motor including the subnanometre-resolution structure of the periplasmic scaffold, an adaptation essential to high torque.

Dupilumab treatment of trichothiodystrophy in a child.

Trichothiodystrophy (TTD) is a rare congenital disorder caused by genetic mutations, leading to hair and skin abnormalities. We report successful treatment of a TTD case using dupilumab, a monoclonal antibody targeting IL-4Rα. The patient, a 7-year-old boy, exhibited significant improvement in skin and hair conditions, suggesting the potential of dupilumab as a therapeutic option for TTD.

Dermoscopy features of infantile perianal pyramidal protrusion.

Infantile perianal pyramidal protrusion (IPPP) is a benign condition generally noted in childhood but may persist for several years. Dermoscopy may help to distinguish it from other conditions, particularly genital warts. We report six cases of IPPP and describe the dermoscopic features that will distinguish these lesions from verrucae.