Biomedical Engineering Reference
In-Depth Information
of the zebra fish nervous system, the recording period allows imaging of nerve fibers from the initial
bud stage, starting from the neural plate to the eventual formation of the neural tube. These proof-of-
concept studies are an important step toward phenotype screening, where the nervous system develop-
ment can be compared between normal and mutant zebra fish whose genes have been manipulated
(Hsieh et al., 2008b).
A recent study has pushed the technology further by quantifying and automatically annotating the
SHG intensity from microtubules as a marker for cell division (Olivier et al., 2010). During each cell
division, the mitotic spindle transiently appears to separate the duplicated chromosomes; so, the SHG
intensity rises and falls. This change in SHG intensity can be fitted to provide a time stamp for each cell
division within the embryo (Figure 7.7). Combining with third-harmonic imaging of the cell boundaries,
(a)
t
0
+ 2′
t
0
+ 8′
t
0
- 7′
t
0
(b)
T
0
+ 285s
T
0
+ 95s
T
0
+ 190s
SHG
T
0
+ 380s
δ
T
(c)
111
s
80
60
40
20
0
285
380
475
0
95
190
Time (s)
FIgurE 7.7
Using SHG intensity as a time stamp for cell division in whole-embryo imaging. (a) Time-lapse
sequence of SHG images from a zebra fish embryo during cell division. Continuous imaging did not prevent normal
embryonic development. Scale bar = 20 μm. (b) Large field-of-view images contain multiple dividing sister cells.
The spot intensity of SHG was used to mark the time and location of cell division. (c) Quantification of the time-
lapse SHG intensity revealed that two sister cells, indicated by arrowheads in (b), were divided at different times
during the same division cycle. (Reprinted from Olivier, N. et al., 2010. Cell lineage reconstruction of early zebrafish
embryos using label-free nonlinear microscopy.
Science,
329, 967-971. Copyright 2010, with permissions from the
American Association for the Advancement of Science.)
