What’s the Dirt on the Meiss Lab?


 Meet the Lab

Figure 1: Left to Right: Mishael Ohanwadi, Kate Alianiello, Dr. Sarah Meiss in the field at Dr. Kerney’s constructed wetland.

Kate is a rising sophomore and it is her first summer doing X-Sig. She is a Health Science and Italian major who also plays on the tennis team. This summer she has been doing a lot of reading for fun when outside of the lab and spending some time in the kitchen making new recipes. She has traveled with Dr. Meiss and Mishael to a few different wetlands where they collected soil, water, root, and Cattail leaf samples. This summer she is researching the difference between natural and constructed wetlands, specifically microbiome diversity in soil and their potential role in the nitrogen cycle. 


This summer, Mishael is working on the genetic variations of Typha in different wetlands as well as epigenetic factors that affect their genes in relation to microbial activities of wetland in Dr. Meiss’ lab at Gettysburg College. She is a rising sophomore, an international student from Liberia, and she is double majoring in Biology and Environmental Studies. The summer has been very rewarding for Mishael as she has been more absorbed into hobbies like dancing, bike riding, cooking, and being a little artistic here and there outside of the lab. Mishael hopes that this research can provide a larger understanding on how wetlands can better be preserved so we can keep benefiting from them.

Dr. Meiss

I am a  Visiting Assistant Professor (VAP) here at Gettysburg College and am originally from Harrisburg, PA and I just love this area.  I have been working in Higher Education for over 15 years and have spent time working and teaching at Denison University, Lawrence Berkeley National Laboratory, California University of PA, and now Gettysburg College.   I earned my Ph.D. In Environmental Microbiology and Plant Biology in an Interdisciplinary Molecular and Cellular Program at Ohio University.  It was there where I fell in love with plants, mushrooms, and bacteria, and began my research in learning how they all communicated and lived together.  Today, my research focuses on the microbial ecology of soils and their relationship with the success of constructed and natural wetlands. 

What are you researching this summer?

        Did you know wetlands are sometimes referred to as “earth’s kidneys” due to their long-term capacity to filter pollutants from the water that flows through them? A major source of pollutants is fertilizers from farms, but wetlands can remove nutrients like phosphorus and nitrogen from water by transforming them into materials that plants can use and gas that can be released into the atmosphere. And who are the ones responsible for this incredible transformation process…bacteria and fungi, of course!

This summer, we are looking at the microbiome of both natural and mitigated wetlands.  It is often observed that natural wetlands survive without mitigation, while constructed wetlands need mitigation and usually cannot survive, meaning they dry up and can no longer support plants and animals, longer than 5 years. The cause of this is highly underexplored, but it is hypothesized that lack of biodiversity in the soil in mitigated wetlands may be a larger contributing factor. The purpose of this research is to determine if there is a difference in the microbial community of the wetlands and the microbiome’s relationship with environmental factors and plants, specifically Typha (cattail) which is a popular wetland plant. 

What methods do you use to gather data?

At each wetland we visit, we conduct a non-invasive survey by collecting soil, water, cattail roots leaves and identify other plants around the shoreline. We also take water pH and temperature reading, along with measuring the depth. Later we test water samples for the presence of ammonia nitrogen, nitrate nitrogen, phosphate, and dissolved oxygen. We also test soil samples for pH, moisture content, nitrogen, potassium, and phosphorus using the LaMotte test kit. 

Figure 2: Water sample being tested for Nitrate using LaMotte test kit.
Figure 3: Typha angustifolia from Jug Bay Wetland Sanctuary, Maryland.
Figure 4: Typha latifolia from Happel’s Meadow Wetland Preserve in Gettysburg, PA.

Kate and Mishael use the samples a little bit differently to gather data. Kate uses nutrient agar and R2A to grow bacteria from the soil, water and root samples. After a few days, bacteria covers almost the entirety of the plate. Who knew so many bacteria could be hiding in our samples?! Once the bacteria grow, Kate transports them to new plates and spreads the bacteria to isolate the colonies. She then gram stains bacteria to determine if it is gram positive or negative, the shape and size. After isolating the bacteria, she can use PCR (Polymerase Chain Reaction) to sequence 16S rRNA gene sequencing to identify the bacteria. She will also be testing the presence of the nosZ gene in these bacteria, which is responsible for producing an enzyme that converts nitrous oxide into nitrogen gas. She tests this by running gel electrophoresis. 

Figure 5: A Gram Stain being completed using crystal violet.

Figure 6: Gram positive bacillus bacteria are shown at the 1000x microscope magnification. 

Figure 7: Root of Typha latifolia in a petri dish with nutrient agar. Bacteria are growing on the plate. 

Mishael uses the plant sample to isolate DNA and run PCR on them to identify different genes of Typha, she tests for chlorophyll content, and she grows fungi from the roots of the plants to examine soil health. How she typically does all of these is by chopping and grinding some plant in a mortar with pestle, she then adds an extraction buffer that is made up of 1% SDS and NACl to release the cells of the plant. After that, she uses a pipet to take out the cell liquid, centrifuge them three times (4mins, 4mins, and 2mins) using a microcentrifuge to detach the supernatant and separate the DNA to be sequenced later. 

Figure 8: Typha leaves ground with mortar and pestle.
Figure 9: Extracted plant cells.
Figure 10: Extracted Typha DNA.

Next, a chlorophyll content test is run by measuring 0.25g of leaf sample and then adding 10mL of 80% ethanol to it in a test tube. The is left to boil for about 10 minutes in order to extract the chlorophyll from the leaves of the plant to be run in a spectrometer that measures light absorbance of the chlorophyll (Ethanol evaporates when heated so the measurements will not be exact after boiling).

Figure 11: Chlorophyll extracted from Typha leaves in a test tube after being boiled.

Finally, to grow fungi from the root of the plant, she plates root samples into petri dishes prepared with tryptic soy agar mixed with antibiotics. The antibiotic kills any bacteria attached to the roots and allows fungi to grow alone without having any interference or multiple things growing at the same time. When grown, fungi DNA is later isolated to be sequenced as well. 

What is your morning routine before coming to the lab?

Mishael: My morning routine is very basic. Before coming to the lab, I wake up around 7:30 AM to make breakfast. After that, I usually like to read while eating and I have just started reading the book Sing Unburied Sing by Jesmyn Ward, it’s just something I do before stepping out to start my day. When I’m done with that, I pack my bag, put on some Harry Styles’ music, and bike for about five minutes to the Bullet Hole to grab a cup of  coffee and then head to the Science Center. 

Kate: When I wake up, I first decide what I want to make for breakfast. It usually is a smoothie, yogurt with fruit and granola, or eggs with avocado toast, and always a cup of coffee. I then get ready and head to the science center. 

Dr. Meiss: I always start my day with a cup of coffee and a to-do list.  This helps me take some quiet time by myself and prioritize what my day will look like.  Balancing a career and a family life isn’t always easy, so it takes time and care.  

What is the hardest part of this research?

Mishael: This research has been fun to work on so far but the hardest part for me would be the field work we do and it’s mostly about going to different wetlands to collect samples we need to work on. One of the challenging parts is when the wetland is drying out, it becomes difficult to collect water samples and we spend longer time out in the field searching for water. We also deal with ticks out in the field, but other days are very exciting.

Kate: I personally think that a lot of the work that we do in the lab can be very tedious and repetitive, so sometimes it is difficult to stay focused. I have learned many new techniques, like streaking bacteria, gram staining, and PCR, but it is sometimes frustrating when I realize that I didn’t do them successfully and have to start over on certain things. 

Dr. Meiss: Some days, when it seems that I am not making much progress, it can be difficult, but it isn’t that bad.  The most difficult thing for me and research is caring about something so passionately and devoting my life’s work to it and then hearing that some people don’t care or do not think it is important.  I believe it is everyone’s responsibility to care for the world we live in, we are part of it.  Not everyone does.  

What do you like most about this research?

Kate: This summer I have enjoyed working in the microbiology lab because I have learned so many new techniques and have become more independent in the lab. This research has given me the opportunity to work with and grow bacteria and fungi, which I have always been interested in since high school. Additionally, I find it interesting how the microbiome, which is often overlooked by many, plays a large role in the wetland areas that we are researching and the environment as a whole. 

Mishael: What I like most about this research is exploring how something (Wetland) that is easily overlooked can have a significantly great impact on society at large. The amount of benefits we continue to receive from wetland ecosystems plays a tremendous role in our lives and it is very crucial to continue to preserve these ecosystems as well as the plants and animals that thrive there. 

Dr. Meiss: What I love about my research is that it has both field and laboratory components and I never seem to be able to choose which one I enjoy more.   I love nature and I love the fact that all organisms live together and work together.  It really feels great to be spending my days learning as much as I can about that topic, most of the time I can’t believe that I get to do it for my job.

What do you hope to achieve and what impact will this research bring to the world at large?

Wetlands have many important benefits to our world at large. They are able to improve water quality, recycle many nutrients in the ecosystem, provide flood protection, control erosion, and prevent other coastal disasters from occurring. They also serve as habitats for many endangered species and help give balance to the overall ecosystem. 

We hope that if we find a significant difference between the types of bacteria in the mitigated and natural wetlands that we could implement these bacteria into the microbial community in mitigated wetlands. If we find that the wetlands have similar environmental characteristics, it’s possible that these newly introduced bacteria could thrive and increase constructed wetlands longevity. If there are no significant differences in the microbiome, it is possible that another factor is causing constructed wetlands’ shorter life span. We also hope to understand how epigenetic factors of different wetland locations can have influence on the genetic variations of Typha. Overall, we hope that our research could prevent wetland endangerment as they are highly productive environments that have many benefits. 

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