Their conversation might go something like this: “I’m so glad you guys made it. I can’t wait for us to get in. I’ve heard nothing but great things about the food here and I’m starving.”
According to Juan González, Ph.D., associate professor of biology and associate dean of graduate studies in the School of Natural Sciences and Mathematics, “conversations” like that among bacteria – yes, bacteria – the rod-shaped single-celled microorganisms – may someday be deciphered by scientists.
“Bacteria are on the verge of starvation all of the time. And one thing we have discovered in the last four years centers on the idea that bacteria talk to each other. They have a molecular conversation with each other,” González said.
“For many years, microbiologists thought of bacteria as very simple organisms,” he continued. “Well, they are, indeed, simple and selfish organisms that are just out there looking for food. But bacteria, as simple as they are, are very aware of their environment. They can sense the presence of other bacteria around them. They can sense whether they are from the same group as they are or whether the bacteria are competitors. And the way they sense all of this is through the exchange of molecular signals.”
These conclusions are the results of five years of research that González directed at The University of Texas at Dallas. González tapped his undergraduate students for help in conducting his studies.
Thoughts about Undergraduates
“The undergraduates here are just fantastic, as good as or even better than some of the students I met at MIT or UCLA. They are fantastic in classes, very interactive and they are also very good at research. I have, in fact, four or five undergraduate students working in my lab doing research. They can be as good as many graduate students: Very responsible, very attentive to detail, very careful in their work, and technically very proficient. Very, very good,” he said.
González, as you may have already surmised, carries a great deal of affection for his students and his work.
“One of the fun things, I guess, about our job is you see the new students coming in their first year. They are naïve, they do not know that much and they are apprehensive. They cannot formulate or solve problems on their own. And then a year later – bam! – they are full-blown scientists. They think they can do everything. They can think on their own and they think they know more than you do, and that’s always fun,” González said laughingly, smiling and shaking his head.
“A career in science, I tell students, is not for everybody. It’s a very difficult career. It is a lot of work, a lot of frustration. I tell students that if out of every 10 experiments they do, one of them turns out as they thought it would, they can have a beautiful career in science. Those are good odds,” he said.
Understanding How Bacteria Work
But enough of this mutual admiration society. What’s happening with the bacteria?
“If you have bacteria within a small space, say a wound or in the root of a plant, these molecular signals that the bacteria produce continuously start to accumulate in large amounts.
“Once that happens, these signals are everywhere, even inside the cells, and now the cells can sense, ‘Hmm. There must be other bacteria here because we have a lot of this particular signal molecule in this environment.’ That is usually a signal to bacteria that they must be close to a potential host,” González explained. “At that point, the bacteria must decide if it is worth trying to get inside that host.
“The path for bacteria to get inside a plant is, in many ways, similar to the way in which Salmonella, for example, invade the intestinal tract. They send signals to your cells that fool them into thinking that they are not really bacteria,” González said. “Then the cells engulf the bacteria and that allows them to get inside. So it’s a trick, sending false signals. It is a conversation based on molecules being exchanged.”
González said his research “has always been based on trying to elucidate those signals. We are trying to understand that conversation that occurs between bacteria and plant cells or human cells. If you understand those signals, you can manage them. You can try to neutralize them. You can try to eliminate them.”
González said this may have future applications, including replacing antibiotics in the fight against infections with a solution that would render bacteria helpless by scrambling their molecular signals.
“One of the things that we are trying to do is find ways in which we can neutralize those signals,” González said. “And there are different ways in which you can do that. First, you can look for enzymes that will cause a change in the conformation of the signals so that now they cannot act as such.
“Another way you can deal with this is finding a way to trap the signals inside the bacteria so they can never get out. If they cannot go out, even if there are a lot of bacteria, they are blind to each other. If they are not aware that there are a lot of them out there, they never go ahead and make the virulence factors necessary for invasion. If we find ways to do that, in essence, we are creating a new kind of antibiotic,” he said.
- Updated: February 6, 2006