SYTOX Orange staining of mammary sheep tissues and milk.
A. Milk from sheep infected with S. uberis. B. Same sample as A, after benzonase treatment. C. Milk collected before infection. D. Tissue from sheep infected with S. uberis. E. Same as D, after benzonase treatment. The arrows indicate the residual staining of bacteria, now visible after digestion of the extracellular DNA in NETs. F. Mammary tissues collected from a healthy animal. Even when a strong contrast is applied to the image, no extranuclear DNA can be seen inside the mammary alveolus.