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201710EJS01-004

《自然》：氨化作用的全新竞争者
Nature: Ammonia Oxidizers have New Competition

The nitrogen cycle is incredibly important in many industries, such as agriculture and waste water treatment. The microbes involved in this cycle are the stars of the show; one bacteria in particular was highlighted in Nature this past week. In addition, NMT could further this research by measuring nitrogen-based molecules in this bacteria.

The Paper

One main step of the nitrogen cycle is when certain microbes take and oxidize ammonia (NH3) to use for energy. This step is interesting, because there are tons of bacteria and archaea eager for ammonia, but very little is actually available in their environment. They have to make do with the tiniest scraps they can find, and beat the competing microbes for food. Usually, the archaea prevail.

Nature just published “Kinetic analysis of a complete nitrifier reveals an oligotrophic lifestyle,” by K. Dimitri Kits and Michael Wagner et al. of the University of Vienna. They cultured one particularly interesting bacteria, Nitrospira inopinata, that not only oxidizes ammonia, but nitrite (NO2-) as well, which is not common. They wondered, does this bacteria have an advantage over other ammonia-oxidizers? Who would win in a fight?  

In this experiment, researchers compared three oxidizers on their affinity for ammonia: Ammonia-oxidizing bacteria (AOB), ammonia-oxidizing archaea (AOA), and Nitrospira inopinata. Out of the three, they found that N. inopinata had the best affinity. Even though it could fall back to another source of energy, this champion bacteria still made the most efficient use of ammonia, beating out it’s closest competitors.

NMT Connection

It seems that NMT would be a perfect tool to further this research on the intriguing N. inopinata. Not only can NMT measure ammonium (NH4+) flux, but it also has sensors available for nitrate (NO3-), which is one of the products from this bacteria’s reactions. NH4+ and NO3- have both been measured by NMT numerous times, such as in a Nitrosomonas europaea biofilm, in a study by Eric McLamore et al. in 2009. They measured a large biofilm measuring more than 5 cm both wide and long, but NMT can measure a wide variety of sample sizes, so smaller colonies could easily be tested as well.

Now, this new Nature study discovered that N. inopinata has an impressive ammonia affinity compared to other microbes. But when measured with NMT, what will its ammonium flux profile actually look like, and what will this indicate about it’s use of ammonia? What will the nitrate efflux look like? How will these data look compared to the other microbes?

Only NMT can answer these questions with real time flux measurement in live colonies of N. inopinata. As this research moves forward, it will surely lead to new techniques for agricultural practices and wastewater protocols. One must wonder, what will be the next discovery about this amazing bacteria?

For more NMT connections, see NMT Publications: http://youngerusa.com/index.php/publications

References

K Dimitri Kits, et al. Kinetic analysis of a complete nitrifier reveals an oligotrophic lifestyle. Nature, 2017. 269–272.

Eric S. McLamore, et al. Non-invasive self-referencing electrochemical sensors for quantifying real-time biofilm analyte flux. Biotechnology and Bioengineering, 2009.102:791–799.