Hi there, I, as a L2 french student in Petnica, wondered about interactions. What interactions ? all of them. Organisms with other organisms, organisms with their environment, environment with their environment, and so much more. As an example, birds might migrate when no food is left, seeking for environment where food is abundant. Since we were to work on micro-organisms, or microbes I chose to work on Pseudomonas putida and see how colonies, gathering of living individuals that share common interests (here the sharing of nutrients), of this particular specie would develop when put really close to a source of nutrient, here we used sugar.
So, Will the shape of these colonies change when food is near ? Will they reach for their food ?
Finding an answer to this question could be useful to know this organism better, but also to maybe be able to lead the development in different directions according to our will !
How did I manage to test my hypothesis ? Well I put food near the colonies and took pictures of the boxes where they grew, and observed if the colonies developed in the direction of the food, and only in this direction. However, giving more food to bacteria than they already have will end up making them grow more than the rest of the colonies. Therefore, we have to keep that in mind this little detail, in order to have useful conclusions. This method gives us the length increase of the chosen individuals, according to their total area !
What did we observe ? did colonies deployed their arms ? Well according to the graph we obtained, some of them did. Indeed here are the results :
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1 = sugar, 2 = no sugar, Number of colonies = 17 per condition
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Here this graph shows the difference of approximate length of colonies, proportionally to their area, comparing two different conditions, with or without sugar. As we can see, the average colony next to sugar got longer than the average colony next to no sugar. That means that colonies did kind of reach for the food, at least most of them did. However, as we can see, some of them were hungrier than other and developed way more than other. This detail is an indicator that even if it is clear that the presence of sugar helps colonies grow faster and stronger, it still is influenced by the fact that colonies would develop more anyway with food.
How do we use this information ? Well, we did find an information about the little arms of bacteria, however there are some points that should not be forgotten. The fact that all the colonies were in the same box means that they could have interacted between themselves, remember, organisms with organisms ? well the only way to prevent that from happening is to separate them. This could be a way to ensure that the results we have are completely true. What’s next ? maybe we will try to take pictures of their arms… oh wait, we did :)
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| The bright zone is the "arm" of this colony, quite big right ! |
Of course, if you want to know more, here are some links ! :
-"Pseudomonas Putida." Wikipedia. Wikimedia Foundation, n.d. Web. 18 Sept. 2016.
-Harwood, C. S., "American Society for MicrobiologyJournal of Bacteriology." Flagellation of Pseudomonas Putida and Analysis of Its Motile Behavior. N.p., 1989. Web. 16 Sept. 2016.
-Harwood, C. S., and M. Rivelli And. "C S Harwood." Aromatic Acids Are Chemoattractants for Pseudomonas Putida. N.p., 1984. Web. 16 Sept. 2016.
-My other coworkers blogs and reports !
-Tanguy Chotel
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