It takes a Team to Tango!

Myxococcus xanthus is a rod-shaped species of bacteria, that exhibits various forms of self-organizing behavior as a response to environmental cues.

Under normal conditions with abundant food, it exists as a predatory, saprophytic single-species biofilm (layer of bacterial cells) called a swarm.

A swarm of M. xanthus is a distributed system, containing millions of entities that communicate among themselves in a non-centralized fashion.

Simple patterns of cooperative behavior among the members of the colony combine to generate complex group behaviors in a process known as "stigmergy”.

For example, the tendency for one cell to glide only when in direct contact with another results in the colony forming swarms called "wolf-packs" that may up to several inches wide.

This behavior is advantageous to the members of the swarm, as it increases the concentration of extracellular digestive enzymes secreted by the bacteria, thus facilitating predatory feeding.

Likewise, during stressful conditions, the bacteria undergo a process in which about 100,000 individual cells aggregate to form a structure called the fruiting body over the course of several hours.

On the interior of the fruiting body, the rod-shaped cells turn into spherical, thick-walled spores that can survive starvation. Scout cells on the periphery search for prey.

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“I’m hungry”, remarked the biggest one in the group. “Yes, yes, so are we”, said the irritable one.

“What do you think we are doing, playing marbles?” said the sarcastic one. “Oh, give him a break” said the “good” one. “You guys are moving too fast”, remarked the lazy one.

“Can’t be avoided”, said the serious one. “You want to move at all, you have to move in a pack.”

They were all elongated rod shaped creatures— just single bacterial cells, in fact— moving together on a lumpy field.

One had to glide over the other to move ahead; but this was a fine arrangement, for a single bacterium could never move if it were on its own.

The group was always a mix of characters— there was serious, bossy cell; a kind and smiling one; some irritable and some lazy; but they kept together despite the differences.

“Look… food ahead!!!” cried the biggest cell, which was always hungry for food. The call was enough for the rest of the group.

“Full charge on!” cried the leader, the serious, bossy one, and they hurriedly stumbled— or glided— over each other to get at the “food”.

The food happened to be a lump of another set of bacterial cells. “They seem to have been placed there for our benefit”, frowned the leader.

“Are we walking into a trap?”

“Food is good, food is good” chanted the biggest one, rushing onwards, and forcing the rest to rush too. “No trap, the food is good.”

The good cell was always particular about niceties, even before eating a victim. “Hi there”, it smiled. “What kind of cells are you?”

“We are the Coli cells”, said a group of panic stricken tiny cells all lined together neatly in a circle. “The E. coli cells.”

“Wow! You’re the famous ones! The ones the researchers always used”, said the good cell cheerfully.

“Just like they are using us now I suppose. Oh, I forgot to introduce myself— I mean, ourselves— we are the Myxococcus Xanthus cells and we specialize in—”
Before it could finish the sentence, the cells started howling in pain and dissolving right in front of them.

“Hey, what did you guys do that for?” said the good cell, a little indignantly. “I was just introducing myself and you send out your digestive juices! Is that any way to treat new friends?”

“Oh of course not”, said the Sarcastic cell. “But it seems absolutely okay to eat your prey after you’ve become friends with them, is it?”

“Oh, stop squabbling you two”, scolded the lazy cell. “Wasting all your energy in discussing useless stuff.”

“Well at least we got food”, the big cell gave a burp.

Suddenly they felt a huge shudder— almost like an earthquake. “Hey, what’s that?” said the irritable cell. “I hate this nonsense in the lab.

They treat us worse than animals!”

“These humans think too much of themselves”, said the sarcastic one. “They keep forgetting they’ve evolved from us.”

“Not only have they forgotten that, but they have forgotten all the good qualities they had as single cells, or as a colony.

All they do is fight with each other and cheat each other. And now they have to study us to re-learn the good things again!”

The rest of them gazed in wonder at this outburst, which had come from the lazy cell. This was rather a long speech from the lazy cell, who usually was too lazy to say more than a few words at a time.

Plop! They found themselves in a new field, along with other swarms of their own kind. “This is a trick”, muttered the serious one darkly.

“Oh, I don’t think the humans are that bad. What makes you think it’s a trick?” asked the good cell.

“Look at the large number of us here. And look! There isn’t a single bit of food here. We will starve!”

This was true. All around, they could only find barren stretches. No food was around at all.
They glided around for a long time, searching for food.

But then they realized that all the other swarms were doing the same, and were unsuccessful.

And they realized their bodies were slowly turning circular, as they were becoming starved and undernourished.

“We will all die”, remarked the good cell sadly. “I wish we didn’t have to.”

“You won’t have to”, came a new voice. All the cells in the swarm turned around. Two tough looking rod – shaped cells stood before them.

“Just join the gang and become clump together with the rest. We are just collecting everyone together”, said one of them.

“Yeah, you will just stay asleep and inactive for a time inside this big group. And we are scout cells.

We will cover all of you at the outer side and protect you like soldiers, look for food and wake you up when it’s time.”

Thankfully, the group of bacteria huddled together along with the larger groups, and went to sleep, while the scout cells stood guard.

A keen eye watched all this through a microscope. The eye belonged to Ken, a researcher. “Hey, guys, look at this, they’re forming a fruiting body!”

The rest of the lab continued with their work, while one or two raised their heads in curiosity.

More heads turned when Alice entered the room. “Who’s coming with me to the party now?” she announced breezily.

“Me!” “Me too!” A bunch of interns and research assistants happily joined Alice and went out. The rest moped and sulked.

“They go off to enjoy and we do the work”, said one.

“I say, what do we tell the Professor when he comes in?”, said another.

So when the Professor walked in an hour later, he punished the entire lab— some for going out to party, and the rest, for letting them go.

Ken too, had to abandon his experiment to bear his part of the punishment— which was cleaning out the cages of the guinea pigs.

The Myxococcus bacteria had a few hours of peace in their petri dish, not being prodded and starved by turns.

The scout cells, who observed the goings-on, laughed to themselves. “Stupid humans” they giggled. “If they’d worked as a team like us, they might have finished their work and had a party too!”