If you’re ever on social media, you have probably seen ads for probiotic yogurts and similar products, with a promise that they will improve your “gut health.”

“Honestly, none of that is based on solid, scientific research,” says Michael M. Meijler.

“There are various ideas and hypotheses to how this may work, but nothing is known at the molecular level,” Meijler, a professor in the department of chemistry in Ben-Gurion University of the Negev (BGU), tells ISRAEL21c.

Living in a bacterial world

Meijler researches chemical communication within and between species. He develops chemical tools to figure out the molecular mechanisms that guide these interactions and regulate the balance between competition and coexistence.

“What I like the most is studying how bacteria talk to each other; how bacteria send chemical signals to each other, within one population of specific bacteria, in order to collaborate,” Meijler says. 

He explains that bacteria work together because when they are alone, the actions they can take within their respective environments are limited. 

“When the bacterial cell is alone, the most it can do is to acquire nutrition and multiply,” Meijler notes.

“It cannot defend itself against attacks from other bacteria or viruses; it can’t capture large amounts of iron [some bacteria derive energy by oxidizing dissolved iron], and it can’t create biofilm,” which increases the bacteria’s resistance against the body’s defense mechanisms.

The ecosystems

Meijler discovered that the signals one population of bacteria send to another can be sensed by other bacteria that are “listening in.” 

It’s logical to assume this would have “a huge impact on the overall state of a certain ecosystem” inside human beings — for instance, skin, airways, ears and gut.

“Each ecosystem can house hundreds of different species of bacteria, so there must be a huge amount of communication going on,” he adds.   

Additionally, bacteria can move from one body part to another, using a “motor,” which is the bacterial flagellum. Meijler says bacteria normally move in search of a better ecosystem.

“Bacteria know what population size they can get [in a specific ecosystem] in order not to cause a disturbance of the body,” he says, adding that if the body dies, so do the bacteria, even if not immediately. 

“The disturbance of this careful equilibrium is what defines sickness.”  

A good example is intestinal problems, such as Crohn’s disease, when one “bad” bacterial species overwhelms the environment, killing or expelling the “good” bacteria. 

We’ve got chemistry 

Meijler explains the lack of insight into the behavior of bacteria is due to the fact that it’s mainly biologists rather than chemists who study this field. 

“But biologists generally cannot synthesize molecules and they have a hard time analyzing their specific structures, or finding new molecules,” he notes. “They don’t look enough at the chemistry; that’s something only chemists can do.” 

Yet Meijler is among few chemists worldwide studying bacterial communication (“I don’t suffer from a lack of courage or foolishness,” he jokes), in part because this type of research is very expensive. Some of the necessary instruments cost more than “a few expensive cars.”

The gut-brain axis 

In recent years there has been a lot of research into the so-called gut-brain axis, the two-way biochemical signaling between the gastrointestinal tract and the central nervous system.

Over the last year or two, Meijler’s lab has also been investigating whether signals of bacterial systems in the gut can influence brain chemistry and behavior.

His team hypothesizes that gut bacteria send chemical signals to the brain by secreting molecules of compounds that can break the blood-brain barrier.

“That’s what we propose could affect brain chemistry,” Meijler adds. 

The research could have a huge impact on how we understand certain disorders, such as anxiety or stress disorders, as well as human health in general. 

“If we prove this hypothesis true, it could alter very strongly the way that we see what is happening in the gut; we’d be the first to do so,” the professor says. 

From Amsterdam to Beersheva 

Born in Amsterdam in 1970, Meijler combined studies in chemistry and organic synthesis at the University of Amsterdam, where he completed his bachelor’s and master’s degrees. 

Between 1997 and 2022, Meijler did PhD studies in bioorganic chemistry at the Weizmann Institute of Science in Israel. “That’s where I learned to synthesize molecules; that was a lot of fun,” he says. 

Meijler then spent several years as a postdoctoral fellow at The Scripps Research Institute in San Diego, California. 

At the end of 2006, he returned to Israel having accepted a position at BGU in Beersheva, where he was promoted to associate professor in 2011 and to full professor in 2015. 

Incidentally, Meijler’s wife, Lital Alfonta, is a full professor at BGU’s department of life sciences. 

“We got married in the middle of our PhDs; later, we both applied to several universities in Israel, and Ben-Gurion University gave us both an offer to start our own labs,” he adds. 

Future Nobel Prize winner?

Recently, the France-based Human Frontier Science Program (HFSP), which funds basic research in life sciences, awarded a $1.2 million grant to Meijler to support his study on gut bacteria and whether their chemical signals can affect human behavior. 

The HFSP is unique in that it supports “high risk, high gain” research. 

“Only two to three percent of research proposals submitted to the HFSP gets funded,” notes Meijler.

Meijler’s lab will collaborate on the study with Prof. Karina Xavier’s Bacterial Signaling Laboratory at Fundação Calouste Gulbenkian in Portugal, and Prof. Brittany Needham’s Stark Neurosciences Research Institute at Indiana University in the US.

The foreign labs will trial the hypothesis on animals, something which his lab does not do. “And we don’t do experiments on humans, of course; that’s illegal, generally,” he smiles.

Since 1990, more than 8,500 researchers from more than 70 countries have been supported by HFSP. Of these, 29 awardees have gone on to receive the Nobel Prize.

Will Prof. Michael Meijler be the 30th HFSP awardee to clinch the Nobel Prize? We have a good gut feeling.