We inhale a host of potentially infectious germs with each breath, but most are removed before they can cause harm, trapped in mucus and cleared out by the beating hairs of cells lining our airway. However, bacteria may evade this first line of defence by altering the organisation of cells in the trachea, the tube connecting the throat and lungs. These 3D representations of mouse tracheal tissue, constructed using fluorescence microscopy images, reveal the effect of infection with Streptococcus pneumoniae, which causes pneumonia when it enters the lungs. In the bottom panel, exposure to bacteria (shown in yellow) triggers the breakdown of the carefully ordered structure seen in the healthy tissue (top). Networks of protein fibres (in red) become disorganised, and the hairs, or cilia (in green), no longer form a plane surface. These changes will distort the flow of mucus along the airway, preventing efficient removal of unwanted particles.
BPoD stands for Biomedical Picture of the Day. Managed by the MRC London Institute of Medical Sciences the website aims to engage everyone, young and old, in the wonders of biomedicine. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.
BPoD is also available in Catalan at www.bpod.cat with translations by the University of Valencia.