Figure 5.

The response of Triton X-100 extracted sperm to Ca²⁺. (A) Representative fields of Enkur^+/+ (left panel) and Enkur^tm/tm sperm (right panel) following addition of 1 mM CaCl₂. Flagella of Enkur^+/+ sperm adopt a highly coiled anti-hook form while those of Enkur^tm/tm exhibit little or no curvature. (B) Curvature is expressed as the straight line distance between the head-flagellum junction and a point on the flagellum 20 μm from the head junction. Flagella of both genotypes were relatively straight in the absence of added Ca²⁺ medium. Following addition of 1 mM Ca²⁺ flagella of Enkur^+/+ sperm become coiled, but there is no observed effect on the flagella of Enkur^tm/tm sperm. Data represents mean ± SD of five animals for each genotype (>20 sperm were assessed for each animal; horizontal line above bars represents statistical differences by two tailed t-test).