Biomedical Engineering Reference
In-Depth Information
FIgurE 7.2
SHG imaging of microtubule bundles. (a) Single neurites of a neuron from a 3-day-old dissociated
rat hippocampal culture. The bright solid circles are fluorescent beads used for intensity calibration. (Reprinted
from Kwan, A. C. et al., 2008. Polarized microtubule arrays in apical dendrites and axons.
Proceedings of the
National Academy of Sciences of the United States of America
, 105, 11370-11375. Copyright 2008, with permission
from the National Academy of Sciences, USA.) (b) Dense microtubule networks within the neurites of an
Aplysia
neuron imaged after 3 days in culture. The neuron has a large nucleus so that the centrally located microtubules may
be within adhesion areas that are underneath the cell body. (Reprinted from
Current Opinion in Neurobiology
, 14,
Mertz, J. Nonlinear microscopy: New techniques and applications. 610-616. Copyright 2004, with permission from
Elsevier.) (c) Cilia lining the walls of the aquaductus cerebri in rat brain stem slices. (Reprinted from Dombeck, D.
A. et al., 2003. Uniform polarity microtubule assemblies imaged in native brain tissue by second-harmonic genera-
tion microscopy.
Proceedings of the National Academy of Sciences of the United States of America
, 100, 7081-7086.
Copyright 2003, with permission from the National Academy of Sciences, USA.) (d) The apical dendrites of pyra-
midal neurons in an acute hippocampal slice of a transgenic Alzheimer's disease mouse model. The spherical object
in the center of the image is a senile plaque, the hallmark pathological lesion for the disease. (Reprinted from Kwan,
A. C. et al., 2009. Optical visualization of Alzheimer's pathology via multiphoton-excited intrinsic fluorescence
and second harmonic generation.
Optics Express
, 17, 3679-3689. Copyright 2009, with permission from the Optical
Society of America.) Scale bar = 30 μm, (a); 50 μm, (b); 100 μm, (c); and 30 μm, (d).
Barnes et al., 2010). SHG from microtubule bundles in the cilia of the rat brain stem (Dombeck et al.,
2003), axoneme of sea urchin (Odin et al., 2009), and astroglial filaments of the spinal cord (Fu et al.,
2007) have also been described.
In addition to the biophysical argument based on structural polarity, there are two main lines of
experimental evidence confirming microtubules as a source of SHG. First, there is a clear correspondence
