Fig. 2
Trypanosoma-infected mice show shorter circadian period. a Representative actograms of daily wheel-running activity of control and infected mice in constant darkness (DD). All running-wheel experiments involve seven days on LD12:12 followed by 10 days in DD to confirm that all animals have a normal circadian rhythm, after which animals are either infected or injected with vehicle in the dark. Horizontal black and white bars at the top of each actogram represent lights off and on for the initial acclimatization period, respectively. b Period of running-wheel activity of control (n = 6) and infected (n = 14) mice. c Representative actograms of daily wheel-running activity of control and infected mice in constant dark. Animals were treated with suramin (20 mg/kg) i.p. on day 21 post-infection (blue line). d Period of control (n = 8) and infected (n = 27) mice; *adjusted p < 0.05, **p < 0.01, ***p < 0.001, FDR method Benjamini–Hochberg, for panels b and d. e Representative actograms of daily wheel-running activity of a control and three infected animals when challenged with consecutive dark to light period transitions. DD-1 first period in DD started on day 60 post-infection, LD-1 when mice were transferred to LD, and DD-2 when transferred to a new DD period. f Circular phase plots of activity onset for the dark periods represented on the top panel. A circle represents a 24-h clock, and activity onset phases of individual mice were calculated as angles and plotted as colored symbols outside the circle. The direction of the vector indicates mean phase angle. Phase data are replotted on bottom panel as Circadian Time (CT). Shaded area represents subjective night; **adjusted p < 0.01, FDR method Benjamini–Hochberg. g Relative daytime activity in the light period after the dark period 1; **p < 0.01, tested with Mann–Whitney test. Orange dotted line represents T. brucei infection start and blue dotted line the suramin treatment
