ET polyurethane-degrading microbe (ETPUM) Case Study # 1
ELVIS Meltdown – Part 2
by Richard Stewart
Your direct microscopic observation of microorganisms in the soil samples has sparked your boss’ interest. He is eager to determine what type of microorganism(s) is present….eukaryotic or prokaryotic; gram-positive or gram-negative; or maybe something new, never before seen on Earth. He sends a sample of the soil off to a biochemistry laboratory for direct analysis.
You are equally interested in the nature of the microbes, but instead of directly analyzing the soil, you first isolate a pure culture of a microorganism that you demonstrate has the ability to degrade polyurethane. You send a sample of this pure culture off the same biochemistry laboratory for analysis.
Later, you receive the results of the analysis of your boss’ sample and your pure sample.
|Boss’s sample||your sample|
|80 S ribosomes||+||–|
|70 S ribosomes||+||+|
|Phospholipid membranes containing|
electron transport proteins
|Flagellar basal body proteins||+||+|
|Nuclear pore proteins||+||–|
ET polyurethane-degrading microbe
“I’m not sure what’s wrong with your sample, little buddy / little lady, but my results prove that we are dealing with a new kind of life form here…I’m calling it the “preuk-aryote” because it has components characteristic of both prokaryotes and eukaryotes. It’s time for a press conference!” boasts your boss.
Later on, as you are getting ready to head home after a long day in the lab you hear your boss bellow “What the H-E-double hockey sticks is going on here!!” You ask him what happened. “This morning I put a few thousand cells from your pure culture of ETPUM onto 2 slides in some water, but then I had to go to that press conference, and I didn’t have enough time to look at the cells carefully except to notice that they were uniformly distributed under the coverslip. I didn’t want the slides to dry out so I sealed the edges of the coverslips.
On this slide I used a rubber gasket to make the seal, and on this slide I used a Lycra gasket. Now look at the cell distribution! On the rubber-sealed slide, the cells are still uniformly distributed, but on the Lycra-sealed slide all the cells have congregated around the edge of the coverslip.
Look… they are all over at the edges; none are left in the middle part of the slide. Could somebody have come in here and moved all those ETPUM cells over to the edges? But who? Maybe someone small with really small tweezers. Did you see anyone like that lurking around this scope? Nah…I need to get a grip on reality here. No tweezers could be that small. Here’s what probably happened: the microbes used their eyes to see that there was some Lycra over at the edges. So then they ‘beamed’ themselves over to the edges to have some lunch munching on polyurethane.”
Read the introduction, then answer the questions
Research your response
Cite your sources.
How would go about isolating your pure culture?
If your goal is to characterize the ET polyurethane-degrading microbe (ETPUM), whose results are more informative: yours or your boss s? Why? What do your results indicate about the nature of this microbe?
Does its biochemical composition most closely resemble that of a prokaryote or a eukaryote? Gram-positive or Gram-negative? Do you agree with your boss conclusion that the ETPUM is a prokaryotic-eukaryotic hybrid? Why or why not?
What are the ways bacteria can move through their world? Describe some mechanisms of motility. Come up with at least 2 possible alternative explanations for the amazing redistribution of the ETPUM on the Lycra-sealed slide.
Both of your explanations should consider how the microbes sensed the presence of polyurethane. One of your answers should not involve flagella.
Are the ETPUM organisms exhibiting taxis? What might be the stimulus for the taxis?
ET polyurethane-degrading microbe (ETPUM)