By Jennifer Wong-Ala
“Ew, you work with bacteria?! Aren’t you afraid of getting sick?” This is what I usually hear whenever I talk to people who are not familiar with the different types of bacteria. When most people think of bacteria, they think of the harmful germs that get them sick. The “good” bacteria I work with are called HIMB30, from the Gammaproteobacteria class. Gammaproteobacteria are common in the marine environment, and HIMB30’s name comes from the Hawai‘i Institute of Marine Biology on the east side of ‘Oahu, where it was isolated from.
So why is this bacteria “good”? HIMB30 is not harmful to human health, and serves many functions. Think of HIMB30 as a hybrid car. A hybrid car uses gas to power its engine and has an electric battery that it can recharge. HIMB30 is heterotrophic — meaning it consumes “food,” or organic matter in this case, like the gas you put in a car, but it also has the ability to use light to create extra energy, much like the rechargeable battery. Genes for phototrophy and genes that have the ability to fix CO2 into an energy source were found in HIMB30, which is unusual in this order of bacteria. With my research, I am trying to figure out how HIMB30 uses these genes to acquire its energy.
The gene found in HIMB30 that has the ability to conduct phototrophy is called proteorhodopsin. Proteorhodopsin is related to a pigment found in your eyes called rhodopsin that allows us to see different colors. This protein is able to harvest energy from the sun and it functions as a light-driven proton pump. A proton pump can be thought of as a gate that allows protons to enter the mitochondria. Since the discovery of proteorhodopsin, many bacteria have been found to contain this gene.
It is estimated that in one liter of water, there is about a billion bacteria. Since there are so many bacteria in the ocean, it must be easy to bring them from the ocean to the lab to start growing and experimenting with them right? Well, it is not quite that simple. It is suggested that less than 1% of the microorganisms in nature are able to be cultivated in the lab today. This being said there are even less microorganisms that can be cultivated that contain proteorhodopsin and this makes them difficult to study. This makes HIMB30 extra special, since it has proteorhodopsin and we have it growing in culture in our lab. I have been doing experiments with the cultures in order to learn more about the metabolism of HIMB30.
Many of you may ask, why is this important? The carbon cycle in the ocean is responsible for the cycling of nutrients. In this cycle, bacteria play a huge part of the marine food web and process more than half of all the flow of carbon-based matter. There are many different types of bacteria in the ocean. Photosynthetic bacteria use sunlight and convert it into energy. Mixotrophs can use sunlight and organic matter for energy, while heterotrophic bacteria attack other organisms. Now where does HIMB30 come into all of this? HIMB30 has characteristics showing that it may be a photolithoautotroph. This means that it can use the energy it gets from light to convert substances such as carbs, fats, and proteins into simple substances. It also uses a form of sulfur and CO2 as a source of carbon for this to occur. But the big question is how would this affect the carbon cycle in the ocean? It is still unknown how some bacteria utilize the proteorhodopsin gene and the effect it can have on the carbon cycle.
In February, I presented these exciting research findings at the 2014 Ocean Sciences Meeting held in Honolulu. This was the first conference I attended and let me tell you, it was huge! At first it was overwhelming, but after a while I got the hang of planning out my day. At the end of the week, I was sad that the conference was over. I learned a lot from the vastly different sessions and I met many great people whom I plan on keeping in touch with for years to come. Science has taken me farther than I had ever imagined and I am super excited that this is only the beginning.
Jennifer Wong-Ala is an undergraduate student at Kapi‘olani Community College and is currently conducting research as a Center for Microbial Oceanography: Research and Education (C-MORE) Scholar. She plans on transferring to UH Mānoa in Fall 2015 and earning a BS in Global Environmental Sciences. She is a mentee as part of the SOEST/KCC Maile Mentoring Bridge Program (www.soest.hawaii.edu/maile).