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AS SUBWAY COMMUTERS MINGLE, THEIR MICROBES DO TOO

As Subway Commuters Mingle, Their Microbes Do Too

         

Summary: A research group in the University of Hong Kong wanted to get a holistic view of how many microbes interact with humans in a city. They specifically studied the Hong Kong metro system which provided the team with a way to look at microbe populations throughout the city. About 5 million people are riding the metro every day. In their study, they had volunteers ride the metro during the morning and during the night. They collected bacteria by telling the volunteers to hold on to the handrails and then swab their hands (palms) after they got off the metro. The goal of their study is to understand what microbes on the metro transfer onto the riders. After the samples underwent DNA sequence analysis they discovered that the microbes the riders encountered were very dependent on time. They discovered that the morning riders were mostly exposed to microbes that belonged to the same environment surrounding different metro lines. The evening riders had a mixture of microbes some also belonging to different metro lines but the majority belonged to microbes that live on human skin. Through their study, they discovered that different metro lines had distinct populations of microbes in the morning but in the evening the populations had blended together.

Connections: During lecture, we have talked a lot about how we have an immune system to protect us from microbes. Specifically, we have an innate (non-specific) immune system which consist of physical barriers such as skin and hair. A lot of the microbes found on the hands of the volunteers belonged to a mix of different microbes found in different metro lines and microbes that are found on the human skin. Without these physical barriers a lot of people will be exposed to the microbes and could potentially get sick. We have also talked about ways of disinfecting places to prevent the spread of microbes. Even though, the metro employees were cleaning the train rails that people touched throughout the day, the commuter traffic through out the day were spreading microbes along with it. So, although the rails were being cleaned through the day the microbial spreading was still occurring.

Critical analysis: We already know that microbes are everywhere. The goal of this study wasn’t to scare the metro riders. They want to educate the public that might not fully understand what microbes are, that they are everywhere and they can spread quickly. Especially in public places, through the study they wanted to help commuters understand what they can do to protect themselves and reduce the spread of bacteria.  Many people grab these rails and then might rub their eyes or eat something without washing their hands. I think this study is important so people have better hygiene after being in public spaces. Meaning perhaps washing their hands as soon as they can or having hand sanitizer handy when they can’t wash their hands.

Question: I wonder if the rails were being cleaned though out the day for the purpose of the experiment only. Are they cleaned on a regular basis though-out the day when it’s not for   study? If not, would they have potentially found other more harmful bacteria?

 

 

Summary: A research team from the University of Leuven in Belgium has found that gut bacteria can produce neurotransmitters like serotonin and dopamine which can influence mood and behavior if the chemical messengers are sent to receptors in the brain. Through their research, they also identified two strains of bacteria that are absent in the guts of individuals that have been diagnosed with depression. In their study over 2,000 gut bacteria was studied from European participants. Genomes of 532 strains of bacteria were tested to see if the bacteria had the capability to produce neurotransmitters. In their findings, it was noted that over 90% of the tested bacteria could produce neurotransmitters. It was also noticed that Coprococcus (influences mental health) and Dialister bacteria was depleted from participants suffering from depression even if they were taken antidepressants.

Connections: In lectures, we have discussed the human micro biome. Specifically, we have covered that the gut community is highly diverse including at least 16,000 species. Good bacteria found in the gut line the entire digestive system with most bacteria living in the intestines and colon. The bacteria found in the gut affects everything such as metabolism, mood and immune system. Which is why the connection between gut health and brain function isn’t surprising because we know that the gut micro biome is crucial for our health.

Critical analysis: I believe that this discovery could be very beneficial to individuals suffering from clinical depression. Perhaps having a healthy gut microbiome could be more beneficial than taking long term anti-depressants as studies have shown that long term use can exacerbate the inflammatory response. There is still much more to uncover about the bacteria in the gut. For example, understanding how the Coprococcus and the Dialister strains function in the gut. As of now this study has only identified bacteria that can influence mental health at a genus level. It is why identifying which species of Dialister and Dialister reduces depression.

Question: If the specific species of both bacteria’s that influence mental health are identified can they be introduced to individuals lacking such bacteria to reduce depression?

https://www.smithsonianmag.com/science-nature/scientists-find-possible-link-between-gut-bacteria-and-depression-180971411/

Summary:

This article explains how genetically modified Salmonella targets tumor cells and makes the immune system aggressive towards cancer cells. There’s no arguing that cancer is very aggressive and sticks around because the immune system is unable to recognize these foreign invaders. This article explains how scientist have modified Salmonella bacteria to generate an immune response against human colon cancer cells which have been implanted in mice. The results have been favorable because some of the tumors have shrunk and it has also prevented metastasizing. Scientist modified Salmonella typhimurium so that it secretes the protein FlaB from another bacterium called Vibrio. The experiment was carried out by injecting the Salmonella into 20 mice that had human colon cancers and noticed that after three days the mice had cleared most of the bacteria but the tumorous tissue in their colons was full of Salmonella. A few days later the tumors were then undetectable in 11 out of the 20 mice.

 Connections: We have discussed in class some of the ways that the idea to use bacteria to fight diseases have been around for a while. Salmonella is usually associate with being “bad’, different types of the salmonella bacteria can cause illnesses in humans. Salmonella thrives in environments with no oxygen and tumors also gave no oxygen so it has a lot of dead cells the bacteria can feed on. We have also been discussing bacterial structures; a protein in the Vibrio flagellum (a tail used for swimming) caused a strong response from immune cells (FlaB). The Salmonella was then altered so that it would secrete the protein.   I found that very interesting because they took something from the Vibrio bacterium and altered the Salmonellas function to secrete this protein to fight cancer.

Critical analysis: I really enjoyed this article, it was short and easy to comprehend. I know salmonella is a bacterium found in the intestines of humans and animals. But I also know it can be bad if live salmonella bacteria enter the body which can cause illness.   I always thought of Salmonella as being this bad thing that we careful of. I found it very fascinating that Salmonella was modified to targets cancers cells and the results were great based on the mice.

Questions: Would modified Salmonella that secretes FlaB work on all types of cancers? How advanced can the cancer be? What modifications to it are necessary so that it safe for humans and can be used as anticancer therapy? Will it work on other types of cancer?

https://www.sciencemag.org/news/2017/02/scientists-turn-food-poisoning-microbe-powerful-cancer-fighter?r3f_986=https://www.google.com/