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Download the Protein Blotting Guide
Download the Stem Cell Guide for Life Science Researchers
:: Posted by American Biotechnologist on 12-05-2011
As a follow up to Bio-Rad’s acquisition of QuantaLife, we are proud to present the following educational training video: “An Introduction to Droplet Digital PCR”, given by award winning field application specialist Dr. Sean Taylor.
Be sure to stay tuned for the advanced training video which will be posted in the near future.
:: Posted by American Biotechnologist on 12-01-2011
QuantaLife, which was recently acquired by Bio-Rad Laboratories, produces an innovative droplet digital PCR system that provides quantification of target molecules with unprecedented precision and sensitivity. In the videos that follow, QuantaLife’s VP of Application Development Dr. Serge Saxonov, introduces Droplet Digital™ PCR and explains various aspects of the technology.
Now, we are proud to present you with a 43 page protein blotting guide put together by Bio-Rad Laboratories. The guide is organized into two parts which cover the theory and methods behind protein blotting. You will learn topics such as methods and instrumentation, the difference between various membranes and tranfer buffers, the ins and outs of transfer conditions, detection and imaging and a host of different blotting and detection protocols.
The guide is fairly technical and is appropriate for both novice and advanced users alike.
:: Posted by American Biotechnologist on 10-17-2011
With its proprietary transfer buffer, the Trans-Blot Turbo system generates very fast transfer even for high molecular weight proteins. However, as indicated previously, the gel composition, i.e. the acrylamide – bis-acrylamide network density, influences the transfer efficiency. A protein can more easily move out of the gel during the transfer if it is located in a portion of gel that has the widest pore structure. As proteins above 150 kD are always located on the first top part of a gel, the most efficient transfer of those large proteins is achieved when using gradient gel with a concentration of 4% of acrylamide – bis-acrylamide at the top of the gel. The transfer efficiency of proteins from an Any kD homogeneous acrylamide gel and a 4-20% gradient gel is illustrated.
Qualitative transfer efficiency comparison of HMW proteins on homogeneous acrylamide % and gradient gel. Precision Plus Protein™ Unstained standard and E. Coli homogenate (20 μg) were run on both Criterion TGX Any kD Stain-Free and 4-20% gels at 300V for 18 min. The total protein content was detected with the Stain-Free technology using the Gel-Doc EZ imaging system. The gels were then transferred with the Trans-Blot Turbo system with the 7 min preset program using the Trans-Blot Turbo PVDF transfer packs. The total protein content remaining in the gel is detected with the Stain-Free detection, using the same exposure parameters as used with the gels before the transfer for reliable comparison. The content of protein was also detected with the Stain-Free detection on the membrane. Even if most of the proteins are transferred in 7 min, the gradient gel contains less HMW proteins than the homogeneous gel after the transfer.
:: Posted by American Biotechnologist on 10-16-2011
In theory, increasing the power input and duration of an electrophoretic transfer results in the transfer of more protein out of a gel.
In practice, however, test runs should be used to evaluate transfer efficiency at various field strengths and transfer times for each set of proteins of interest.
The optimum transfer conditions depend on a number of factors, including the size, charge and electrophoretic mobility of the protein, the type of gel and transfer buffer used, and the type of transfer system being used.
In a semi-dry transfer system, the distance between electrodes is determined only by the thickness of the gel-membrane sandwich, and buffering and cooling capacity is limited to the buffer in the filter paper. As a result, the field strength is maximized in semi-dry systems, and the limited buffering and cooling capacity restricts the transfer time. Though power conditions may be varied with the power supply, semi-dry transfers often operate best within a narrow range of settings.