Ultramicroscopic observation of recombinant adenoassociated virus type 2 on the surface of formvarcarbon coated copper grids under different relative humidity and incubation time using negative stain transmission electron microscopy

  • S Liu
  • C Niu
  • X Li
  • H Chen
Keywords: rAAV-2 virion, ultramicroscopic morphology, relative humidity, formvar-carbon, transmission electron microscopy.


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.

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eISSN: 1684-5315