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Protistology Workshop
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reconstruction of the flagellar apparatus

AIM - to understand the spatial relationships among the various components of the basal bodies of the flagellar apparatus.

Consult the Protistiary entries on 3D reconstruction, homology , and orientation.

The objective of establishing the organization of the flagellar apparatus is partly to better understand how the organelle functions and what it does. However, this work was primarily motivated by a need to clarify the relationships of the various parts of the flagellar apparatus in different taxa so that homologies could be resolved.

Visit the micro*graph environment and select one organism to work with. In 2005, it would be nice to develop a good accounting of the structure in Percolomonas cosmpolitus so that we can build a demonstration around it.

Review the content that is available on the web site to get a sense of what you have to work with. As discussed in Protistiary , it is most helpful if you can find series of sections through the specimen. Sections that pass axially across kinetosomes or along their length are particular helpful.

Access large versions of the images

Confirm that all orientations follow the same convention, as if viewed from base to tip, with anterior of cell to the top of the picture and the right side of the cell to the left of the image. If this is not correct, slip the images and arrange with the faculty to have the revised image(s) put back into the micro*graph database

If there is more than one basal body, you will need to identify some component that allows you to distinguish which is which. The rootlet structures are never symmetrical. The distinction may initially be arbitrary (A, B, C, etc.) but later you should be able to work out whether it is the front left kinetosome, etc.

Develop a rough sketch of the parts that are associated with the roots. There are typically 4-6 rootlet structures associated with each flagellar apparatus. Begin with the obvious.

Once you have a rough idea of what is in the cell, you can then move to trying to draw them out. Typically, display the largest image on a screen, overlay an overhead transparency sheet, and sketch out the location of the elements using colour coding.

 

Images by D J Patterson

Powerpoint series

These sketches need only to be rough at this stage, but retain the information about the negative number.

You can then align the sketches on top of each other to see how the elements relate to each other. This can be done on a bench top, in Photoshop, Powerpoint or as noted in the Protistiary environment, there are an array of software packages to do this. The key step is to use the sketches to revisit the original negatives and to refine your understanding.

Draw out the image. Begin with the basal bodies as simple cylinders, identify the start point of roots, their relative size and shape, the direction they follow, length and terminations.

Do not allow your understanding to be based on a single series of sections - there is no guarantee that every cell has the same parts, nor that the parts remain fixed in location in living cells. In the end, you should be in a position to interpret all images in terms of your model.

The final product is a drawing. In many cases, the organisms in micro*graph have been subject to prior study and some published account may be available. Where possible, name the components using terms that are critically defined . We will add the results to the Protistiary and/or micro*graph environments

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