The ChemiGeniusQ Gel Documentation System from Syngene is a compact system for acquiring gel photographs. Due to its small size, it can be easily accommodated in any part of the laboratory. Additionally, it is one of the least expensive of all gel documentation instruments available. The machine is totally automated and is connected to the computer through a serial port. The CCD camera in the instrument is well protected, which ensures that camera damage is practically impossible. Protein/peptide gels stained using Coomassie or silver stain or DNA/RNA gels stained using ethidium bromide can easily be captured on this system. For viewing Coomassie stained gels, a separate white light pad is available (a standard converter screen is typically found in other gel viewing systems). By using a separate white light source in this system, the UV lamp is not consumed during the process of acquiring protein gel photos. A standard 10 filter wheel comes with the machine for acquiring images of gels stained with different kinds of dyes. The UV filter is provided as a default filter for imaging agarose gels stained with ethidium bromide for DNA/RNA. The other filters can be purchased separately.
The system has several advantages. First, the CCD camera provides a very high resolution image (1392 x 1040 pixels or approximately 1.44 megapixels). Second, an excellent zooming capacity can be obtained with the motor controlled camera. Third, chemiluminescence can be performed because of the peltier cooled CCD camera. Fourth, the machine can be modified with epi-UV, using two different wavelength UV lamps, for TLC (thin layer chromatography) imaging, enabling the image to be captured from above. Additionally, the UV transilluminator can be physically removed from the machine, used for normal gel viewing purposes and has an intensity adjustor for cutting out bands without sample damage related to intense UV light. As a measure of safety, if any of the UV lights (either transilluminator or epi-UV) are on and the chamber is opened accidentally, the UV light automatically gets switched off preventing accidental UV exposure to humans. If required, this setting can be overridden but proper precautions should be taken.
The software used for operating the instrument, GeneSnap, is very easy to handle and can be run in a multi-user environment (operating systems like Microsoft Windows 2000/XP). Like the machine, which takes up very little physical space in the laboratory, the software occupies little hard disk space in the computer. An interface card comes with the machine, which is required to connect the camera to the computer. Images acquired can be saved in 16-bit format, however, the 8-bit format is best for exporting images. This is not of great concern, as CCD-acquired images usually do not lose resolution even after multiple factors of zooming. The main disadvantage with the software is that simple copy-pasting of images is not possible. The software also saves images only in black-and-white. Pseudo-coloring of gels, which is offered by most other software packages, is possible but is not saved in the file. Moreover, images cannot be rotated, though they can be flipped and inverted. Though a live image of the gel appears on the screen that helps keep the gel in correct position, a tool that helps make slight modifications in the rotation angle is very useful. An update is made available every six months, which is provided free of cost to licensed users. In addition, the white light inside the chamber does not turn on automatically when the chamber is opened, though the software can be configured for white light initiation upon the start of a run. This will help in correctly placing gels before acquiring pictures.
The instrument is also provided with one other simple software option, GeneTools, which can be used for all densitometric analysis, molecular weight calculation, etc. of images. A good feature of this software package is that images saved in the form of TIF (and other image formats) can be imported for densitometric analysis.
Vikas Jain
Molecular Biophysics Unit
Indian Institute of Science
Bangalore, India