The investigation of a microbe isolated from a home window sill and assessment of its potential pathogenicity

Description: I cultured what appeared to be black looking mold from the window sill of my children’s room behind a fan that blew across their beds.   My concern was whether this was in fact toxic black mold or some other pathogen that could cause them harm.

Figure: completed genome construction of Lactococcus lactis subsp. cremoris.

Biofilm Formation

Biofilm formation

Biofilms allow microbes to live close to one another, participate in genetic exchange, and take advantage of a nutrient rich area. They provide protection against predators, toxins, and are resistant to many antimicrobial chemicals and antibiotics that the cell alone are not.

Cells have the ability of quorum sensing, which allow them to sense the presence of others and communicate with one another.   Through quorum sensing they can stop producing flagella, make more polysaccharide, and increase the efficiency of nutrient transportation.

Common locations of biofilms are teeth, intestines, rocks, soil, plants, medical implants, and pipes used for things like oil and water.

Here I have depicted cells using flagella to swim.   Here they have come together and using their multitude of sticky fimbria they are able to adhere to a surface and produce a polysaccharide biofilm.   I have also depicted sells using their pili to exchange genetic information. The holes in the biofilm are water channels which allow for water and nutrients to flow through increasing the amount of nutrients that is able to be taken in.

Some common bacteria that produce biofilms are Streptococcus sanguinis with the oral cavity, Neisseria gonorrhoeae, Salmonella typhinurium.

Painting with Microbes

Lab section: F02

I wanted to see what the difference would be using the same bacteria on all three plates.   I used Enterobactor aerogenes for the sun on each plate, Serratia marcescens was used for the birds on each plate and Chromobacterium violaceum was used for the oceans.   Both the Eosin Methylene Blue (EMB) and MacConkey plate select for Gram-negative organisms, while the Trypticase soy agar (TSA) plate is a general growth media.   EMB and MacConkey plates are both differential for lactose fermentation.

All three of the bacteria I used are Gram-negative. As seen from the McConkey plate, S. marcescens, E. aerogenes, and C. violaceum all show lactose fermentation as the entire plate is almost clear.   From the EMB plate we can see that lactose acid has been released during fermentation from the green sheen of   C. violaceum and the dark colors of the other two.

The great Sulfolane degrader of the Subarctic.

Article and Link:

Identification and Characterization of a Dominant Sulfolane-Degrading  Rhodoferax sp. via Stable Isotope Probing Combined with Metagenomics

by Christopher Paul Kasanke, R. Eric Collins &  Mary Beth Leigh

published 2/28/2019

Summery: Researchers were able to identify and obtain metagenomics on a microbacteria within the microbial community of the Sulfolane contaminated water aquifer in North Pole, Alaska that is naturally degrading the Sulfolane contaminate.     While microbacteria in other temperate regions of the world: Illinois, Canada and Japan, have identified Sulfolane degraders this is the first in a subarctic climate.   This bacteria, Rhodoferax sp. is found to be the Sulfolane degrader able not only to survive in the subarctic conditions and persist at 4o C, the average temperature of the aquifer year-round, it also

Connections:   This information connects to what we have covered in class in that the identification of Rhodoferax sp. is a further example of niche evolution and how there are different bacteria that evolve doing the same job in different areas in different ways.

Critical analysis: I think it is interesting and exciting that this is the first subarctic microorganism of its kind identified.   I think this paper is scientifically accurate.   The paper has many references, was a continuation of earlier research, processes were explained well and thought through.   I think the researcher does a good job of communicating science to the public, while there were parts that might be a little in depth, I believe that even if someone read it that did not understand exactly what everything meant, they would be able to understand the overall message.

Question: I am curious to know, where is Rhodoferax sp. found around the world, besides Alaska?

Using natural remedies for blasting biofilm

Article and link:

“Blast Biofilm this Winter: New Tulsi Holy Basil Benefits’

Summary: John Douillard, of John Douillard’s Lifespa, claims making tea using Tulsi Holy Basil (Ocimum sanctum), breaks down the biofilm on your teeth that causes plaque.   He says that the herb contains eugenol and ursolic acid. Both are known biofilm disruptors and powerful cleansers.   He says ursolic acid is a quorum sensing inhibitor which enables the ability of the bacteria to communicate so that the biofilm is unable to form.

Connections:   We spoke in class about ability of some bacteria to “talk’ to each other through quorum sensing and their ability to create biofilms through this.   We also spoke about how these biofilms can be harmful or helpful depending on their location and the effects they have on the environment they have established themselves in.

Critical Analysis: While John Douillard has included science in his writing, and he does include scientific references for his information.   Though in these studies they found there was no statistically significant difference between using regular store-bought mouth wash and Ocimum sanctum, they did find that using Ocimum sanctum was better than the studies that used a placebo.   I am a bit skeptical because he wrote the article for his own business on his business page and there is a disclaimer at the bottom of his page that state “The entire contents of this website are based upon the opinions of John Douillard. They are not intended to replace a one-on-one relationship with a qualified health care professional, and they are not intended as medical advice. They are intended as a sharing of knowledge and information from the research and experience of John Douillard and his community. John Douillard encourages you to make your own health care decisions based upon your research and in partnership with a qualified health care professional.’   There is also a disclaimer stating that no part of the information on his page have been evaluated by the FDA.  Though this does not mean he is not pushing other products that do not work and feeding off desperate people.

Question: If people can easily get mouth wash that scientifically works, breaking down the biofilm and inhibiting other biofilm (plaque) from forming, why bother going this route?

A2: Deadly Food Poisoning

Article and Link:

“Student, 20, died in his sleep from food poisoning bug after eating pasta that he’d left out on a worktop for five days’


A college student ate noodles with pasta sauce he had reheated after leaving out for 5 days.   Within 30 minutes he came down with a headache nausea, and stomach cramps.   He began vomiting and having diarrhea.   Thinking he had a case of food poisoning, he went to bed to sleep it off and was found dead in his bed 11 hours later.  Upon investigation it was found he died from Bacillus cereus, which is a spore forming bacteria that produces toxins that causes vomiting and diarrhea.   The autopsy showed that the concentration of B. cereus was so high it caused his liver to shut down.   Samples of the food were analyzed, results determined significant contamination within the pasta, no traces within the sauce.


As we just talked about spores in class, how easy they are to spread and how deadly they can be I found this article fitting.   Having talked about weaponizing spores, this article shows how contaminated food can have deadly effects.   As we were recently talking about generation times, I did some research and found it only takes 26 minutes for B. cereus to double and 8.6 hours do multiply by 1,000,000!   Which sheds light on why the boy died after leaving the food out for 5 days.

Critical Analysis:

I found this article interesting in that it went with a topic we just talk about.   The testing was completed by a medical examiner and scientists, so I believe the results are accurate.   This was written as a news article, they used easy to understand language making it readable for people not in the science community


Could a test stick could be created and marketed that could test for common microbes that cause food poisoning that people could use at home or in restaurants?

Howard Taylor Ricketts

Howard Taylor Ricketts was an American pathologist for whom the Rickettsiaceae family, Rickettsiales order, Rickettsia genus, and Rickettsia rickettsii bacteria are named after.   The genus of Rickettsia is the largest within the Rickettsiaceae family and includes rickettsialpox, other spotted fevers, epidemic typhus, and murine typhus.   Rickettsia rickettsii is a gram-negative, intercellular, coccobacillus bacterium approximately 0.8-2.0 micrometers long that was identified in 1907 by Howard Taylor Ricketts.   R. rickettsia was the first of the Rickettsiales to be identified, is the causative agent of Rocky Mountain spotted fever, and is the most pathogenic of the Rickettsia strains.

Howard Taylor Ricketts was born in Findlay, Ohio February 9, 1871.   He grew up in Nebraska, receiving his bachelor’s degree in 1894.   He went on to receive his medical degree from Northwestern University in 1897, where he conducted research on blastomycosis.  To study the side effects of the pathogens he was researching Howard Ricketts would inject himself with the pathogens.   During this time Ricketts worked as an intern in the Cook County Hospital in Chicago.   From 1899-1901 he worked as a fellow in cutaneous pathology in Rush Medical College, also working in the dermatological clinic.   Howard Ricketts married Myra Tubbs in 1900.   They had two children together, a boy and a girl.     Myra was supportive of his work, took interest in his research and provided him with steady encouragement.

In 1901, his research earned him a teaching offer from the University of Chicago’s Department of Pathology and Bacteriology.   Before accepting the offer, Ricketts traveled to Paris to study at the Pasteur Institute, returning in 1902 to teach and continue his research.

Ricketts took up researching Rocky Mountain spotted fever as a hobby in 1906 to pass the time during an enforced holiday.   He was quickly drawn in by the fascinating pathogen, promptly discovering R. rickettsii is communicable to lower animals and that the Rocky Mountain wood tick, which naturally lives on larger animals, can transmit the disease from a sick animal to a healthy one through its bite.   It has sense been found that the American dog tick and Brown dog ticks are also common carriers.   Through experiments Ricketts also discovered R. rickettsii can be transmitted through the feces of an infected host to a healthy one by ingestion or the feces coming in contacted with broken skin.   Infected female ticks can pass the R. rickettsii gene to their offspring.

In 1909 an outbreak of murine-carried typhus in Mexico caught Ricketts attention due to the apparent similarities between it and Rocky Mountain spotted fever.   In December he traveled with his assistant to Mexico City to help in the research where his research of R. rickettsii was crucial in helping discover the cause and vector of the marine-carried typhus.   On April 23, 1910 they made the announcement the discovery of the micro-organism, in the blood of patients and in the insects of human body lice.   Howard Taylor Ricketts died May 3, 1910 in Mexico of typhus.


Hektoen, L. 1910. “Howard Taylor Ricketts Memorial Address at University of Chicago’. Today in Science. 20 Jan 2019.

“Howard Taylor Ricketts.’ Building for a Long Future Exhibit. The University of Chicago Library. 20 Jan. 2019.

“Howard Taylor Ricketts.’ Wikipedia, The Free Encyclopedia. 20 Jan. 2019.

“Rickettsia rickettsii.’  Wikipedia, The Free Encyclopedia. 20 Jan. 2019.




Heather Hanson

My name is Heather Hanson-Whatley, but for UAF it’s just Heather Hanson.   I’m a senior finishing my biology degree with a minor in psychology.   I currently work in the microbiology lab at Fairbanks Memorial Hospital where they have started a Medical Lab Tech trainee program.   Microbiology is a prerequisite for the certification program I am applying to for the fall to become a medical lab technician, so I am back this semester just to take this class.   I’m excited to learn more about the microbes I am working with on a daily bases.   I have 3 kids that keep me busy and am amused at how much the “littles” have enjoyed learning about bugs and the immune system with me.   Not sure how many 4 year olds like to watch YouTube videos about dendridic cells and macrophages, but their kindergarten teacher is in for a ride next year.   🙂