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Ultramicroscopic
observation of
recombinant
adeno-associated
virus type 2 on
the
surface of formvar-carbon
coated copper grids
under different relative humidity
and incubation time
using negative stain transmission electron microscopy
Shu-Peng Liu1,3, Chun-Ying Niu4,
Xue-Ling Li3 and Heng Chen2,3*
1Institute
of Biomedical Engineering, Shanghai University, Shanghai
200072, P.R. China.
2Shanghai
Information Center for Life Sciences, the Chinese Academy of
Sciences (CAS), Shanghai 200031, P.R. China.
3College
of Life Sciences and Biotechnology, Shanghai Jiaotong
University, Shanghai 200030, P.R. China.
4Department
of Biochemistry, University of Alberta, Edmonton, Alberta,
Canada, T6G
2H7
*Corresponding author. E-mail:
chenheng@sibs.ac.cn.
Tel: +86-21-54922972.
Accepted
25 May, 2009 |
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The
purpose of this investigation was to compare the effects of
different relative humidity (RH) on the microcosmic
conformation of the recombinant
AAV-2
virion at
22°C. rAAV-2 virions prepared on
copper grid were placed in
a
high, middle
or
low RH
cabinet
and
incubated
for
72,
48
and
24 h,
respectively. The rAAV-2 virions
were observed by transmission electron microscope
and the values of
major
axis length,
minor axis length
and
ellipticity
of
the
rAAV-2
virions
were obtained
using
the IMS
cell
image analysis system.
After incubation for 48 and 72 h, the major axis length and
minor axis length
of
the
rAAV-2
virion
started to rapidly decrease in high RH. Conversely, the axis
lengths rapidly increased in low RH. Then,
the
ellipticity
of
the
rAAV-2
virion
would almost tend to approach the identical value of 0.9 for
48 and 72 h incubations in high RH. The results
suggest
that the
rAAV-2
virion
tended to favor a smaller, round, more stable
conformation
in high RH
compared to low RH which
implied
that the
rAAV-2
virion
was
probably prone to living in high relative humidity
conditions.
Key
words:
rAAV-2 virion, ultramicroscopic morphology, relative
humidity, formvar-carbon, transmission electron microscopy. |
