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JAThis long worm-like unicellular organism is a Homalozoon, and it’s trying to feed on a Paramecium; however, Paramecium’s defences are working perfectly and letting it escape.
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Homalozoon and Paramecium are in the same group called ciliates. Although they are single-celled organisms, ciliates show such complex behaviors and strategies to defend themselves and capture food, some of the many reasons that led me to specialize in this group.
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Homalozoon feeds on other unicellulars, but occasionally on microscopic multicellulars too. It has a cell mouth on the tip of the cell that carries tens of little harpoon-like structures called toxicysts; as the name indicates, these little harpoons are full of toxins. Upon contact with a possible food source, Homalozoon ejects these harpoons out of the cell; they pierce the target and release their toxic content into the food, immobilizing it instantly.
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However, some other ciliates, like Paramecium, developed defenses against these structures; Paramecium has similar structures in the cell known as trichocysts. They are like Homalozoon’s toxicysts, but instead of being used for food capture, they are used to create a physical barrier between the toxicysts and the delicate cell of Paramecium. Almost like an airbag of a car, when a Paramecium senses that it came in contact with something that could harm it, it ejects these long structures, pushing the toxicysts away from its cell. It’s so fast, it all happens in 1/100th of a second.
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Another interesting thing: Paramecium’s trichocysts are full of chemical cues that confuse Homalozoon and make it behave like it actually caught food. You can see the Homalozoon actually ingesting the expelled trichocysts as the Paramecium runs away to live another day.
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Fascinating, isn’t it? Thank you for reading. Please consider supporting me for the cost of a cup of coffee per month so I can continue making high-quality original content like this one. I appreciate your support.
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Best,
James Weiss
@jam_and_germs
