cytoskeletal protein actin and the molecular motor non-muscle
myosin II is critical for rapid cell movements [20, 32]. Cytoskeletal heterogeneity can be quantified as:
heterogeneity t
ð Þ ¼ sd t
ð Þ=mean t
ð Þ,
ð2Þ
where sd(t) represents the standard deviation of the pixel
values under the mask at time t, after background subtraction
and correction for photobleaching (see Note 28), and mean(t)
indicates the mean pixel value under the mask at time t, also
after background subtraction and photobleaching correction.
Fig. 4 Analyzing embryonic wound closure from time-lapse data. (a) Wound in the epidermis of a Drosophila
embryo expressing myosin:GFP (a) and segmentation of the wound edge using the LiveWire algorithm (a
0 ).
Anterior left, dorsal up. Bars, 5 μm. (b–d) Wound area over time (b), wound closure rate constant (c), and
mean myosin fluorescence at the wound edge (d) in control embryos (n ¼ 5 embryos). (b, d) Error bars,
standard error of the mean. (c) Error bars, standard deviation; box, standard error of the mean; gray line,
mean. (d) Myosin was quantified in a 0.6-μm-wide mask. Mean values were background-subtracted and
corrected for photobleaching (see Note 28). The resulting curves were normalized to the mean pre-wound
values
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Gordana Scepanovic et al.
myosin II is critical for rapid cell movements [20, 32]. Cytoskeletal heterogeneity can be quantified as:
heterogeneity t
ð Þ ¼ sd t
ð Þ=mean t
ð Þ,
ð2Þ
where sd(t) represents the standard deviation of the pixel
values under the mask at time t, after background subtraction
and correction for photobleaching (see Note 28), and mean(t)
indicates the mean pixel value under the mask at time t, also
after background subtraction and photobleaching correction.
Fig. 4 Analyzing embryonic wound closure from time-lapse data. (a) Wound in the epidermis of a Drosophila
embryo expressing myosin:GFP (a) and segmentation of the wound edge using the LiveWire algorithm (a
0 ).
Anterior left, dorsal up. Bars, 5 μm. (b–d) Wound area over time (b), wound closure rate constant (c), and
mean myosin fluorescence at the wound edge (d) in control embryos (n ¼ 5 embryos). (b, d) Error bars,
standard error of the mean. (c) Error bars, standard deviation; box, standard error of the mean; gray line,
mean. (d) Myosin was quantified in a 0.6-μm-wide mask. Mean values were background-subtracted and
corrected for photobleaching (see Note 28). The resulting curves were normalized to the mean pre-wound
values
218
Gordana Scepanovic et al.