Long-term segmentation-free assessment of head–flagellum movement and intracellular calcium in swimming human sperm

ABSTRACT Human spermatozoa are the archetype of long-term self-organizing transport in nature and critical for reproductive success. They utilize coordinated head flagellar movements to swim long distances within female tract order find fertilize egg. However, date, analysis sperm head–flagellar movements, or indeed those other flagellated microorganisms, remains elusive due limitations microscopy flagellar-tracking techniques. Here, we present a novel methodology based on local orientation isotropy bio-images obtain kinematic physiological parameters individual free-swimming without requiring image segmentation (thresholding). This computer-assisted segmentation-free method evaluates, first time, characteristics movement beating up 9.2 min. We demonstrate its powerful use by showing how releasing Ca2+ from internal stores significantly alters behavior. The allows straightforward generalization bio-imaging applications, such as studies bull Trypanosoma, microorganisms – appealing communities than investigating biology.