Bacteria Could be the Key to Biological ‘Wires’

Article:  “Electricity-conducting bacteria yield secret to tiny batteries, big medical advances”

Source:  Science Daily

Date Published:  April 4, 2019

Summary:  Scientists discovered that Geobacter sulfurreducens is conducting electricity through tiny fibers made of protein that “… surround a core of metal-containing molecules.”   It was previously thought that they were conducting electricity through pili, but new technology has made it possible to examine the smaller structures within the bacteria at a higher resolution.   These bacteria live in environments without oxygen, and they get rid of excess electrons almost as a way of ‘breathing.’   It is thought that this way of conducting electricity could eventually be harnessed and used in medical devices associated with human tissue.

Connections:  This article doesn’t relate exactly to the topics we have covered in class, but it does highlight how some bacteria have unique ways of processing molecules and electrons.   It mentions that these bacteria can also be used to clean up radioactive waste, which we have briefly talked about in class.

Critical Analysis:  I was not aware that bacteria could even conduct electricity, so the fact that they can do that, and people were able to figure out how they are doing it, is pretty cool.   It is also really interesting that the same technology the scientists used for this discovery was used to find a virus that was surviving in boiling acid.   The information seems scientifically accurate since they included quotes from the scientists that performed the research, and they included the citation for the article they were explaining.   I think the author did a good job of simplifying the material as best as they could so that any person could understand it.   It would be easier to understand if you were reading it with some background in biology, but it is not completely necessary to understand the basics of what they were talking about.

Question:  Will these proteins still function the same way if they are taken out of the bacteria and used for medical purposes?   Will the entire bacterium have to be used in the medical devices in order for them to work?

“Cleaning Bacteria” By Karli Fitzgerald

I decided to make a Gram-positive bacterium out of glycerin soap.   I wanted to make a bacterium that we are usually trying to wash away when we wash our hands because it would be ironic to wash your hands with the thing that you are trying to wash off of your hands.   Staphylococcus aureus  is a Gram-positive, coccus-shaped bacterium that is commonly found on skin and can cause infections, and the easiest way to prevent these infections is by washing your hands.   I made two pieces of soap so it would look as though the bacterium was cut in half and you could see inside of it.   I made the outer layer thick and purple to represent the thick peptidoglycan cell wall that stains purple after Gram staining.   Inside one of the halves you can see a couple plasmids, while the other half has the supercoiled DNA.   The little blue dots inside the cell represent ribosomes, and the glitter represents all the proteins and other small molecules you might find in the cytoplasm.

I also made a piece of soap to represent a Gram-negative cell envelope.   The blue layers represent the inner and outer membranes, the orange layers represent the periplasm layers, and the pink layer represents the thin peptidoglycan cell wall.   I made this layer pink because Gram-negative bacteria stain pink after Gram staining.

Pumping May Alter the Microbes in Breast Milk

Article: “Pumping may be linked to an altered microbial mix in breast milk” by Laura Sanders

Source:  Science News

Date Published:  April 1, 2019

Summary:  A study compared the microbial makeup of breast milk from mothers who do not pump at all to breast milk from mothers who pump.   Although the microbes in breast milk is fairly unique from person to person, the researchers found two main differences.   The milk from women who pumped had more bacteria that could cause infections under optimal conditions and fewer bifidobacteria, which are thought to be beneficial bacteria.   It is still unknown as to what impact these differences have on the children, if any, and the origin for these bacteria is also under debate.   Some believe the bacteria from the gut travel to the breast and get into the milk, while others think that babies’ oral bacteria affects the bacteria in the breast.   There is some evidence that ‘baby backwash’ might trigger infection-fighting proteins in milk when the baby is fed directly from the breast, so this would not occur in milk that is pumped.

Connections:  This is related to what we were talking about with the human microbiome and how it can be affected by many different factors.   The way a mother feeds her baby not only affects the microbiome of the baby but the microbiome of her breast and breast milk, as well.

Critical Analysis:  I did not know that the way a baby receives breast milk can change the type of bacteria that occur within the breast milk itself.   Since the milk is made within the mother, I thought that only factors within the mother would affect it, so it is really interesting that babies play such a large role in that microbiome.   The information appears to be scientifically accurate since the author included some quotes from one of the scientists who did the research and did not add much of her own opinion when talking about the information from the research.   It was written well to relay the information from the scientists to people who may not have any science background.   It was easy to understand and follow.

Question:  Once the mother is done breast feeding, do any of the microbes remain in the breast?   Do they get flushed out with the milk or die?   If they do remain, are they there for the rest of her life or will they eventually go away?

Flowers and Sunsets

Karli Fitzgerald

Lab F03 6-9

On the MacConkey agar plate, I tried to create an abstract sunset (except the sun is not setting behind anything).   I used S. marcescens  in the center of the plate because it is not a lactose fermenter.   I was hoping it would turn the center of the agar yellow by releasing ammonia and increasing the pH and leave the microbes colorless/yellowish.   Around the outside, I used E. aerogenes because it is a lactose fermenter.   I was hoping it would leave the outer portion of the agar more pink by releasing acidic lactose fermenting products and turn the colonies pink.   In between the center and the outer rim, I tried only using a few streaks from both bacteria to kind of blend them together and form a gradient of color without completely contaminating either of them.   The idea kind of worked as I had hoped because the bacteria on the outer edge turned more pink, and the bacteria in the center stayed a lighter yellowish color, but the entire agar eventually turned yellow after letting the plate sit for a few days.   This means S. marcescens probably released more ammonia product than E. aerogenes released acidic lactose fermenting products, which increased the pH of the entire agar.   The picture with my hand in it was taken after one day of incubation at 37 °C, and it has more of the coloring I was going for when I created the plate.   The other picture was taken three days after I made the plate.   The plate was incubated for one day, and then sat at room temperature for two days.

On the TSA plate, I tried to create a pretty flower with petals of two different colors, but it did not turn out exactly as I had hoped.   Since the TSA plate is not a differential plate, I did not expect the agar to change colors.   I tried to use S. marcescens  and  C. freundii to create pink and white petals.   The big petals closest to the center were made with S. marcescens, and they were supposed to be pink, but they did not turn out that way.   This could have occurred because the original plate that I streaked it from might have been contaminated with a different bacterium.   The smaller petals around the outside were made with C. freundii, and they did turn out kind of white like they were supposed to.   In the center, I used  M. luteus  because I wanted the center of the flower to be yellow, like pollen, and it actually did turn out yellow.   Even though the pink petals did not turn out how I was expecting, you can still tell it is a flower.

Microbes Can Prevent Potholes…?

Article: “Scientists hope bacteria could be the cure for potholes” by Talia Kirkland

Source:  Fox News

Date Published: Feb. 5, 2019

Summary:   This article/news story explains how bacteria may be an answer to preventing potholes.   Scientists at Drexel University in Philadelphia have found that bacteria (they did not mention a specific species), when mixed with CO2 and calcium, can change the environment around them to self-produce limestone.   When spread out on a road, they can make the road material stronger and more able to withstand damage that would cause potholes.   The technique is not yet being used, but it may be an alternative for better roads in the future.

Connections:    This article relates to what we have been talking about in class because they are introducing CO2 and Ca2+ to the bacteria to (I assume) get them to use a specific metabolic pathway and get the desired product.

Critical Analysis:   I think it is really interesting that it only requires two simple ingredients (CO2 and Ca2+) to get these bacteria to produce limestone.   There may be other underlying factors that contribute to the production of the limestone, but the fact that they figured this out with these simple ingredients that are extremely common is pretty impressive.   The information seemed to be scientifically accurate since they actually interviewed the scientists who did the research; it makes the article a little more credible.   One thing that I found misleading, and a bit frustrating, was that within the article, they kept using the terms pavement and concrete interchangeably, but concrete and asphalt are different materials that are made in different ways.   I don’t know if they actually tested this bacteria mixture on actual roads or not, but I think there would be a difference if they tested them on concrete versus asphalt.   The scientist kept saying “concrete”, which leads me to believe that they experimented with concrete, which is not the same material that roads are usually made out of, as far as I know (I would be surprised if roads in Philadelphia are made out of concrete, although it is possible).   If that is the case, then this mixture may not actually work on pavement (asphalt) to fix potholes, as they are claiming.   It is also possible that they were actually working with pavement and are just using ‘concrete’ incorrectly, which would be confusing to people who know the difference between the two materials!   Other than that, I think the author did a really good job at keeping the information simple enough for any person to understand it.   I think someone who knows nothing about biology would still be able to follow along and understand what they are talking about.

Question:    The scientists say that the bacteria are changing the microenvironment around them to self-produce limestone, which made me wonder- are the bacteria that they are adding the ones who are actually producing the limestone?   If not, then what changes are they making that cause other organisms to produce limestone?

Epithet Epitaphs- Amédée Borrel

Image result for Amà ©dà ©e BorrelBorrelia mazzottii is named after French microbiologist Amédée Borrel.   Borrel was born in Cazouls-lès-Béziers, Hérault, France in 1867.   He studied natural sciences and medicine at the University of Montpellier and became a doctor at age 25 after writing a thesis on epithelioma.   In 1892, he became part of the research staff in Ilya Ilyich Metchnikoff’s lab at the Pasteur Institute in Paris.   There he performed research on tuberculosis, experimented with a possible vaccine for the bubonic plague, and investigated the potential use of antibody protection in experimental cerebral tetanus.   He was the laboratory chief of the microbiology course at the Pasteur Institute from 1896 to 1914, which put him in charge of cultivating and maintaining the collection of microbes in their library.   In 1919, he became the Chair of Bacteriology at the University of Strasbourg.   When he retired from that position, he returned to the Pasteur Institute and performed research on the causes of cancer until he died in 1936.   He is credited for some of the pioneer investigations on the viral theory of cancer.   The Borrelia genus consists of helical bacteria cells that are composed of 3-10 loose coils.   They are surrounded by a surface layer, an outer membrane, endoflagella, and a protoplasmic cylinder; they are Gram-stain-negative and are actively motile.   These bacteria cause tick-borne Lyme disease, relapsing fever, and louse-borne relapsing fever in people.   The species Borrelia mazzottii is named after Mexican physician, Luis Mazzotti, who recovered a relapsing fever spirochete in Mexico in 1953.


Krieg, N. R., Ludwig, W., Whitman, W., Hedlund, B. P., Paster, B. J., Staley, J. T., . . . Parte, A. (Eds.). (1984).  Bergey’s Manual of Systematic Bacteriology(Vol. 4). Williams & Wilkins.

Revolvy, L. (n.d.). “Amédée Borrel” on Retrieved fromédée-Borrel

Wright, D. (2009). Borrels accidental legacy.  Clinical Microbiology and Infection,15(5), 397-399. doi:10.1111/j.1469-0691.2009.02818.x


Intro Post- Karli Fitzgerald

Hello! My name is Karli, and I’m in my third year in the biology program.   I was born and raised here in Fairbanks, and I actually really like it here (except on the reeally cold days of course).   I enjoy doing outdoor activities, and I love sports of all kinds.   I have heard nothing but good things about this class, so I am looking forward to this semester!