"Help! I'm lost!"
Losing your sense of direction can be a real problem, which is why we have so many ways to help us find our place. Maps. Signs. Trails. GPS. All of these things get us where we need to go.
This is also something that is important to animals. Take migration, for example. From birds to butterflies to fish to whales to caribou, many species undertake journeys of thousands of miles, relying on the stars, sense of smell, landmarks, and more to navigate. These make up some of the most impressive feats in the animal kingdom. But what about cells?
Yes, cells. Sure, they're not travelling halfway across the world. But they do travel through bodies, often flowing along an animal's veins and arteries, or respiratory (breathing) systems. To them, these are like superhighways! So how do they not get lost? How do cells solve mazes within living things?
The answer is chemotaxis. This is the name for an ability that cells have to respond to chemical stimulus in their environment. Whoa, come again?
In simpler terms, it's a little like a sense of smell. But for cells. Cells uses chemotaxis to tell where certain things are—or aren't—inside a body. They then use this ability to avoid dead ends and reach their destination. And each cell uses this ability differently.
White blood cells use it to locate 'invaders' that they are built to attack—they can sense their presence. Sperm cells use it to find eggs to fertilize (and make new life!). In each case, chemotaxis act as an instinctive microGPS. It's incredibly effective inside the body of a living thing. But could it be used to help cells find their way through one of the most infamous mazes in history?
The Hampton Court Palace Maze in England is one of the world's oldest and most well-known hedge mazes. (This is a maze made from tall shrubs.) A recent experiment wanted to know if chemotaxis could help cells solve mazes. Mazes like the court palace's!
So scientists set up a microscopic replica of the Hampton maze—as well as several other mazes of various difficulty—and unleashed a bunch of amoebas into it! (Amoebas are single-celled organisms.) To help them out, scientists loaded chemical attractants—substances that the amoebas' chemotaxis would respond to—into the end of the maze.
The results were incredible. Were the amoebas flawless? No. But more often than not, the majority of the amoebas were able to 'see around corners' and avoid dead ends before they even get caught in them. The secret appears to be simple—chemotaxis let the cells know the concentration of the attractant ahead. If there seemed to be a greater concentration in a turn ahead, they would usually take that turn. If there was less of the attractant, the cells would turn back and choose another path.
Watch the cells find their way through the mini-Hampton Court Maze and more in the LiveScience video below!