Bacteria with recording capacity have been created to manage gut health

Bacteria with recording capacity have been created to manage gut health ...

The gut is home to a multitude of bacteria that help us digest food. But what exactly do the microorganisms do inside the body? Which enzymes do they produce, and when? How do the bacteria metabolize health-promoting foods that help us avoid disease?

Researchers at the Department of Biosystems Science and Engineering at ETH Zurich in Basel altered bacteria to form a data logger for gene activity. This is an important step towards advancing the use of sensor bacteria in medicine in future for applications such as diagnosing malnutrition and understanding which diets are beneficial for an individual.

Immune system becomes data logger

Researchers at ETH Zurich developed the data logger function over the past few years. They employed the CRISPR-Cas technique, which is a form of immune system that naturally occurs in many bacterial species. These methods, for example, allow the bacteria to remember viruses with whom they have contacts, and in turn help them fight their future viral attack faster.

The researchers did not worry themselves with DNA snippets of viral intruders, but focused on something else: the method may be used so that the bacteria insert snippets of their own messenger RNA (mRNA) into the CRISPR array. mRNA molecules are the blueprint that cells use to develop proteins. As such, mRNA snippets may reveal which genes are being used to execute proteins.

The researchers inserted the CRISPR array of the bacterial species Fusicatenibacter saccharivorans into a strain of the intestinal bacterium Escherichia coli, which is recognized as safe in humans and available as a probiotic. The transfer included a novel technique called reverse transcriptase, which allows the RNA to be transscribed into DNA, and this procedure, along with other CRISPR-associated proteins, is necessary for the incorporation of the DNA snippet into the C

Obtained information without disturbing the body

Anschlieend, researchers from the University Hospital of Bern and the University of Bern administered these modified gut bacteria to mice in the lab. They collected faecal samples from the animals and isolated the bacterial DNA, which they then used in high-throughput DNA sequencing. This allowed the scientists to examine and reconstruct the genetic information of the mRNA snippets. This allowed them to work through the mass of data and thus which genes are active.

According to Andrew Macpherson, the professor and director of gastroenterology at University Hospital Bern, this new technique allows us to obtain information directly from the gut, without having to disturb intestinal functions. Endoscopies can be uncomfortable for patients and often require immediate intestinal function, because the bowels need to be empty for an examination.

Determining dietary status

Bacteria are very adept at registering environmental hazards and adapting their metabolism to new challenges, according to Macpherson. In experiments with mice that received different foods, the researchers able to demonstrate how the bacteria adapted their metabolism to the appropriate nutrition supply. A report of the findings has been published in the journal Sciencecall_made.

Researchers are looking to develop the technique further so that one day they may research human patients to see how diet affects the gut system and how it affects health. In the future, they hope to utilize the method to determine the dietary status of children or adults. Patients will be able to diagnose malnutrition or choose whether or not to take nutritional supplements.

Determination of inflammation effects in the gut was also observed by the researchers. Both mice with intestinal inflammation and healthy mice were administered the sensor bacteria. In this manner, they could identify the specific mRNA profile of gut bacteria that switch to inflammation mode.

Distinguishing different bacteria

This research, published in the journal Science, has expanded into a scientific experiment that allows researchers to distinguish two strains of bacteria from one other based on individual genetic barcodes. In the future, this will enable scientists to investigate in laboratory animals the function of gene mutations in bacteria, such as normal compared to mutant bacteria. This will allow scientists to investigate this profile for the first time, as it passes through the intestine not only when the bacteria reach the feces, so that information about what was happening when the bacteria was

Another conceivable goal would be to further develop the system to distinguish bacteria''s RNA profiles in the small and large intestine. This further would open the door to applications in environmental monitoring. A study of soil bacteria from a crop field, for example, would investigate whether herbicides had been used.

Safe application possible

The researchers have filed patent applications for the method itself, as well as for the specific RNA profiles that are important for certain nutritional molecules and indicators of intestinal health.

Before the sensor bacteria may be used outside the laboratory, such as human patients, the scientists must clarify various safety and legal issues. Using live genetically engineered microorganisms as diagnostic or therapeutic agents in medicine is a step towards success.

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