Article and link
“Gene expression study sheds new light on African Salmonella’
Science Daily, January 15, 2019 https://www.sciencedaily.com/releases/2019/01/190115144045.htm
Further Reading: https://www.ncbi.nlm.nih.gov/pubmed/30645593
A variant of Salmonella typhimurium (ST) 313 is responsible for the deaths of approximately 400,000 persons ever year in sub-Saharan Africa. Researchers at the University of Liverpool are attempting to understand how the genome of African S. typhimurium, which enters the bloodstream and spreads through the body, differs from the global strains of S. typhimurium which causes gastroenteritis.
By culturing the different Salmonella strains in different environments they could simulate differences of stages within the human infectious timeline. They then analyzed the transcriptome of these two strains and found a multitude of gene expression variations as well as RNA variations. These coincided with metabolic and plasmid differences within the two strains.
This correlates with the information that we have learned about variations in culture mediums in class. As well as what we will be going over in lab. The ability to culture this bacterium in different environments allowed for the researchers to study the gene expression at essentially different time frames in the bacterial life cycle. Say, from an environment similar to that outside of the human body, and then an environment within the human body.
What I found interesting in this article is that the phenotypic expression of genes within one strain has caused such a different in its ability to act as a pathogen. I also never thought of culturing microbes in different environments to simulate gene expression. I just thought you would culture them in their ideal environment and study them as such. Thinking about it now, it makes a great deal of sense to do this, not only to study the activity of pathogens, but to perhaps study microbes and why they fit into their respective niches.
The forum for this article is a scientific forum, and though it is technical it is written in a way that someone who isn’t specifically a microbiologist (such as myself) can understand what is being studied and the accomplishments that this group of researchers have made.
The question that I have is a technical one. How is it that they were able to find out the gene expression of these bacterium from culture? I know that the genome can be sequenced using various methods, but how would one know or ascertain which portions of that genome are being expressed at any given time.
2 Comments for “A2 Microbes in the News”
This is crazy Sam! I never knew that Salmonella was such an issue, but I guess with such issues of uncleaned and heavily contaminated foods and surfaces, it makes sense that it is such an issue, especially in a country that does not have ready access to medical care.
From what I understand, it isn’t exactly an issue of hygiene or cleanliness in the area (though that could be causing the high rate of transmission) but rather that this strain of salmonella has mutated to enable it to enter the bloodstream. Thus, instead of acting as a pathogen in the GI tract, it is a system wide pathogen, causing far more deaths.