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Example 3 - Gel photograph

Study the gel photograph below and answer the questions that follow.. Once you have entered your thoughts in the box provided click on the 'Check your answer' button to see a suggested answer.

Figure 3 SDS-PAGE analysis of purified adenovirus. Lane M Unstained broad range protein marker; lane 1 purified Ad3 virus; lane 2 purified Ad5 virus; (figure used with kind permission from Adil Al-Turabi).

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Questions:

1. Is the figure sufficiently annotated?
2. Is the legend sufficient to make the data comprehensible to the reader without having to refer to the main text of the article or is additional information required?

The labels on this figure are better than on the previous figure, figure 2, as all the lanes are labelled and then explained in the legend. However, the author should also identify each significant band he/she is discussing by adding appropriate labels.

It is clear from the figure that the vertical sliced gels which were not adjacent to each other in the experiment have been juxtaposed to make more effective comparisons. This is acceptable. However, if you do this make sure that the boundaries between the separate gels (or blots) are clearly visible (as they are in this figure) and the original is retained.

The figure has been assigned a number and a title. However, the caption is incomplete. Additional explanatory text is necessary before the figure can be understood without reference to the main article. In particular, the author should include brief descriptions of the methods used and the results obtained.

Therefore, the improved figure would be as shown below: the significant band is labelled (right hand side) and the legend has been extended.

Figure 3 SDS-PAGE analysis of purified adenovirus (Ad). Purified Ad3 and Ad5 virus suspensions were mixed with SDS-PAGE loading buffer and heated to 95°C for 3 minutes. The samples were then run on 10% SDS-PAGE and the protein bands visualised using Coomassie brilliant blue stain. Lane M unstained broad range protein marker; lane 1 purified Ad3 virus; lane 2 purified Ad5 virus. In both lanes 1 and 2, multiple protein bands are visible of which one corresponds to a MW of approximately 26KDa.

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