Bloggers,
Back again to entertain everyone while dropping some knowledge on this week's blog post. This week in lab, we tested if our unknown soil microbe reduced nitrogen to any form. We inoculated our positive control, negative control, and our unknown microbe into a test tube. The positive turned a dark red as seen in the picture below. I couldn't get the picture to rotate, so the positive control is the bottom tube. After ~48 hours, I checked our soil microbe, which is very slow growing, to see if it also turned red. Well, it didn't, but after I added reagent A and reagent B to it, it turned red as seen in the top test tube. This shows that our soil microbe reduces nitrogen to nitrite, hey that's pretty neat.
Nitrogen is an essential to life because of the two macromolecules, proteins and nucleic acids (Vivian et al. 1999). Nitrogen is removed from the environment by nitrification, which plays a vital role in the nitrogen cycle, agriculture, and public health implications. Nitrate reduction performed by an array of bacteria also help in biological processes, accounting for man than 10,000 megatons of inorganic nitrogen transformed every year (Vivian et al. 1999). This shows how important, not only nitrogen is, but the reduction process itself which plays a huge role in everyday processes.
Last week, we tested motility in our unknown microbe which showed to be non-motile. But what is involved in motility? There are four cell structures involved in motility; centrioles, flagella, cilia and basal bodies (Baumann 2014). The two major structures include flagella, which are located on the outer surface and uses whip-like movements to move, and cilia uses a rowing motion to sweep across the surface (Baumann 2014). Over the years, microbes have evolved to be nitrate reducers in order to increase their chance of survival (Cole 1996). Cole states that bacteria can reduce nitrate when the environment is changing when oxygen and nitrogen are scarce, which is essential for survival. Other microbes haven't evolved to be nitrate reducers such as not having the ability to do so and other reasons, but can still acquire nitrogen through a process call nitrogen assimilation (Xu et al. 2012). According to one source, non-nitrate reducing bacteria get this nitrogen in a mutualistic relationship with a plant ( Brundage 2015).
Hopefully this posts states how important nitrogen is, along with nitrate reduction and putting nitrogen into a useful source. So, lets try to identify our microbe after this nitrate reduction test, which was positive. After all of the tests we have run so far, I believe our unknown soil microbe is Lactobacillus or Corynebacterium. All of our tests have pointed in this direction, and like I stated in my blog post two weeks ago, Lactobacillus seems to be the favorite to win it, but we still have work to do. According to our dichotomous key, a non-motile and nitrate reducing microbe along with all of our other tests are pointing us in this direction. So, we will see where it takes us and hopefully we are correct!
See you next week,
Michael Cowan
Last week, we tested motility in our unknown microbe which showed to be non-motile. But what is involved in motility? There are four cell structures involved in motility; centrioles, flagella, cilia and basal bodies (Baumann 2014). The two major structures include flagella, which are located on the outer surface and uses whip-like movements to move, and cilia uses a rowing motion to sweep across the surface (Baumann 2014). Over the years, microbes have evolved to be nitrate reducers in order to increase their chance of survival (Cole 1996). Cole states that bacteria can reduce nitrate when the environment is changing when oxygen and nitrogen are scarce, which is essential for survival. Other microbes haven't evolved to be nitrate reducers such as not having the ability to do so and other reasons, but can still acquire nitrogen through a process call nitrogen assimilation (Xu et al. 2012). According to one source, non-nitrate reducing bacteria get this nitrogen in a mutualistic relationship with a plant ( Brundage 2015).
Hopefully this posts states how important nitrogen is, along with nitrate reduction and putting nitrogen into a useful source. So, lets try to identify our microbe after this nitrate reduction test, which was positive. After all of the tests we have run so far, I believe our unknown soil microbe is Lactobacillus or Corynebacterium. All of our tests have pointed in this direction, and like I stated in my blog post two weeks ago, Lactobacillus seems to be the favorite to win it, but we still have work to do. According to our dichotomous key, a non-motile and nitrate reducing microbe along with all of our other tests are pointing us in this direction. So, we will see where it takes us and hopefully we are correct!
See you next week,
Michael Cowan
http://jb.asm.org/content/181/21/6573.full
http://femsle.oxfordjournals.org/content/136/1/1.abstract
Xu, G.; Fan, X.; Miller, A. J. (2012). "Plant Nitrogen Assimilation and Use Efficiency". Annual Review of Plant Biology 63: 153–182. doi:10.1146/annurev-arplant-042811-105532. PMID 22224450.
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