Volume vs. Length ratio in C. elegans

Hi all! I have a question and I’ve been searching in papers but haven’t gotten any proper answers… Is there any standard analysis/method that we may be able to compare volume of the worms along with their length? I can compare them separately but I was hoping I could do something like the proportion of the worms?! it will be so handy in the study of fat…any suggestions? :-\

Hi,

this topic seems to reappear at regular intervals, so the link below is a good place to start contemplating how you might proceed.

http://www.wormbase.org/forums/index.php?topic=30.msg44#msg44.

If you mean by proportion, volume:length, then a ‘simple’ solution would be to photograph the worms and do the analysis in ImageJ;

http://rsbweb.nih.gov/ij/

Steve

Dear Steve,
I have photographed 25 worms/ condition and have already used Image Pro Express to measure both Volume and the length of the worms, however; as their volume shows significant changes upon different treatments while the length shows no changes so I wanted to find a way to present both on 1 graph or table…something that may make more sense… I wonder if I divide their Volume by the length (V/L) and assuming that the V is for a cylindrical shape(i.e. the worm) then could be presentable as the surface area? Is it even reliable? :-\

Are you measuring volume using length and projected area from your photographs?

Are all the worms synchronised and photographed at the same developmental stage then?

If the length of the worm stays more or less constant (?), then a Wilcoxon’s test + box&whisker graph of volume:unit length ratio vs. group/treatment would be one possibility .

I guess it might also depend on whether the volume increase you observe is restricted to a particular region of the worm and whether this regional change is itself dependent on the worm reaching a particular developmental stage…in that scenario timing of the photographs and accurate staging of the worms becomes very important I guess?

Steve

Dear Steve,
Yes, I always sync. worms to L1s using the so-called egg-prep bleaching method. After putting the L1s on the plates with designated treatments, I take pictures everyday up to 144hrs post hatch and it is done at the same time everyday(let’s say I usually do it at 2pm). So I can confidently exclude that variability…My control untreated Wild Type C. elegans samples exhibit the standard sizes(volume and length) based on several papers … But as in my project I treat worms with different doses of Cholesterol I wanted to see how I can explain the “fatness” in the worms compared to their “fitness”… if I could combine volume and length to one trend/graph or a table with some ratios correlating the size distribution in high fat diet worms…(I’m not sure even that makes sense! but if there is no method maybe I can come up with a method?!)
And btw, thanks so much for your help so far,

Soudi