Science is hard. There’s no beating around the bush. As women it’s even hard because even though it’s 2020 we are still woefully underrepresented.

Growing up I didn’t have a science figure to look up to. My day was filled with Barbie and Disney Princesses because I felt that being a scientist would stifle who I am. I now know that’s not the case and that being a scientist means I can be whoever I want. I want the next generation of scientists to know this truth and encourage them to also pursue their passions in STEM.

https://youtu.be/BhVhXozjqnA

What is a microbiome? Microbiome is tossed around a lot, especially now that kombucha and other probiotic drinks are trending. The microbiome is the term for the genetic material of all the different bacteria in a given community. Usually people talk about the microbiome in reference to the Human Microbiome because it’s most relevant to us. Other species have their own microbiome because, like us, they need bacteria to help them to survive. That’s right! Despite all the negative press they receive, bacteria provide many benefits and help different species get the nutrients they need to survive.

We wouldn’t survive without our microbiome. Bacteria reside all over our body including in our nasal passages, oral cavity, skin, gastrointestinal tract, and urogenital tract (NIH Human Microbiome, Ursell 2012). These bacteria help digest food, support the immune system, and maintain heart and brain health. 

There are harmful bacteria out there. When there is an E. coli outbreak, it doesn’t automatically mean all strains of E. coli are out to harm you. Some strains of E. coli are generally present in our gut and are very beneficial. But those harmful strains, namely E. coli O157 gives the rest of E. coli a bad rep because it produces Shiga toxin, which causes hemorrhaging, vomiting, and diarrhea. 

Read more about the human microbiome:

https://www.hmpdacc.org/overview/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3426293/

While working with bacteria, a lot of my experiments require getting just the cells without any of the media that they are growing in. I can do this by using a centrifuge to “pellet” the cells. Essentially, the centrifuge applies a centripetal force to the cells that are spinning around causing the heavier stuff (in my case the cells) to go to the bottom of the tube and while the lighter stuff stays in the top in the liquid layer.

When I’m doing experiments I usually use a pipette or a syringe to remove the liquid layer (the supernatant) because I need to use the E. coli cells for my experiments, but there are many scientists who use the supernatant because it’s full of a lot of fun things like DNA/RNA, some peptides, and secreted molecules.

When using a centrifuge you want to be mindful of these 3 things: the speed, the time, and the temperature. There’s a lot of papers already published that can guide you in the right direction but depending on what you’re studying, if spin the cells too fast or for too long you’ll cause them to break apart (lyse).

E coli gets a bad reputation. Most people think of food poisoning or lettuce recalls when they think of E. coli, but not all strains are harmful! Actually most strains are very beneficial and we need some strains of E. coli to keep our microbiome fully functioning.

The spindles that are coming coming out of the E. coli drawn here are a mix of pili and flagella. These help the bacteria move through their surroundings usually towards a food source or away from harmful sources (or toxins) in a process known as chemotaxis.

E. coli also produces and secretes a variety of different signals. Some signals, known as quorum sensing molecules, tell bacteria the number of surrounding bacteria. Other signals turn on certain genes thus causing the bacteria to express or repress those genes. When a gene is expressed, the production of the protein corresponding to that gene increases, likewise if the gene is repressed, the corresponding protein sees a decrease in production.

Bacteria don’t make words. So how do they talk with each other?

They make small molecule signals, of varying shapes and sizes, that allow them to communicate with one another and respond to environmental changes. There are many signals that have been well studied, many that remain elusive, and even more that are yet to be discovered.

I’m looking at a particular signal that’s produced by bacteria, it’s formed from mRNA degradation. It’s not been extensively studied before, so we are looking into how the levels of this signal change at different points in bacterial growth as well as how production of this signal changes different bacterial traits.

I’m hoping that I can add pieces to the puzzle so that way one day scientists can have a better understanding of cellular signaling and ways to manipulate bacteria so they aren’t so drug resistant.

What are siderophores? If you’ve never heard of them, you’re not alone. Siderophores were discovered many decades ago and there are hundreds of different types of siderophores because different bacteria produce different siderophores. Siderophores are small molecules that are produced by bacteria to scavenge for Iron (III) that’s outside the cell. While many biological roles of siderophores have been discovered, the full extent of their roles are still being studied. Right now, there is a lot of focus in studying siderophores as agents to introduce antibiotics into the cell as well as their roles in iron isolation from cancerous cells.

Just like us, bacteria need iron as a micronutrient. Essentially, bacteria need iron to grow because many proteins and metabolic pathways require iron. However, most iron is found in the insoluble iron (III) form. Siderophores that are secreted from the cell fight with their host cells for free iron (III) in a game of bacterial warfare. Once iron (III) is bound to the siderophore, the siderophore can reenter the cell through specific receptor proteins. Because of the different pH within the cell the iron (III) is converted to the usable iron (II). Usually after the siderophore has done it’s job, it is broken down within the cell.