1. Directional migration and representative spermatocyte trajectory plots in the absence (A,B) and presence (C,D) of the purified Octo-SAP peptide.
Directional migration and representative spermatocyte trajectory plots in the absence (A,B) and presence (C,D) of the purified Octo-SAP peptide. (A) Rose diagrams showing the distribution of migration angles in the absence of the Octo-SAP peptide in an experiment during 15 min; the migration angles were calculated from x,y coordinates at the beginning and the end of the cell tracks (N=100), and were grouped into 10 deg intervals, with the radius of each wedge indicating the cell number. A Rayleigh uniformity test confirmed that the distribution of migration angles was uniform (P=0.169). (B) Representative cell trajectory plots in the time period from 0 to 15 min. A chemotaxis experiment was performed in the absence of the Octo-SAP peptide. No directed migration was observed and a smaller displacement of the center of mass occurred. (C) As in A, but in the presence of the Octo-SAP peptide. A Rayleigh uniformity test confirmed that the distribution of migration angles was not uniform (P=1.02E–16). (D) Representative cell trajectory plots in the time period from 0 to 15 min. A chemotaxis experiment was performed using a dilution of 1:10 of the Octo-SAP peptide. Spermatocytes moved in the direction of the x-axis, which is by definition the direction of the gradient with higher displacement of center of mass.
Emilia De Lisa et al. J Exp Biol 2013;216:
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