Fig. 4. Acceleration of flagellar beat frequency by bicarbonate. (A,B) In a
large-scale experiment, 90 cells from a single animal were selected randomly
for examination 1-10 minutes after addition to medium Na7.4 containing 0
(
) or 15 (
) mM NaHCO3. Beat frequency (A) and amplitude
(B) were determined by waveform analysis as described in
Fig. 3. Horizontal bars mark
the mean, enclosed by boxes that extend ±1 s.d. (C-E) Beat frequencies
extracted from sperm images collected during perfusion by medium Na7.4 with 0
(, 
), or with Na7.4 containing 1 (
), or 15 (•) mM
NaHCO3 as indicated. Data were averaged from triplicate experiments
each involving three cells from one animal (n=9). Error bars that
were smaller than the symbol were deleted for clarity. In C, half times were
8.8±0.2 and 17.5±0.4 seconds for the indicated bestfit sigmoidal
curves.