Some of the scariest monsters are subtle.carnivorous bacteria Articular Botrys Oligospora It doesn’t seem like a big deal while it’s eating away at rotting wood. But when it senses a live worm, it becomes veritable nightmare fuel, trapping its victims and eating them alive.
Until now, not much was known about how killer fungal attacks occur at the molecular level. Researchers at Taiwan’s Academia Sinica have finally determined how the gene activity of a fungus changes when a nematode gets too close. A. oligospora. A research team led by molecular biologist Hunche Lin discovered that the fungus synthesizes a type of insect glue and additional capture proteins to capture food. It then produces enzymes that break down the worm so it can start eating.
I fell into a trap
A. oligospora They live in the soil and are mostly saprophytic, feeding on decaying organic matter. However, things can quickly change if they notice a lack of nutrients or sense that there are attractive nematodes nearby. From this point on, I go into carnivorous mode.
Lin and his colleagues wanted to find out what happens when this nutrient-starved fungus is introduced into nematodes. Nematode. When the fungus sensed the nematode, it showed a significant increase in DNA replication. This added a copy of the genome to the trapped cell. Trap cells reside within the fungal filaments, or hyphae, and produce a special adhesive that allows the hyphae to stick to the insect when it is trapped.
The most important genetic effects that help the fungus create traps from hyphae are: ribosome biogenesis, allowing for increased protein production. Because ribosomes are where proteins are made, their biogenesis (literally, the production of more ribosomes) controls cell growth and determines how much protein is synthesized.
The researchers also identified a new group of proteins, now known as trap-enriched proteins (TEPs), which are the most commonly produced proteins in fungal trap cells. These are thought to contribute to trapping function rather than formation.
“Given that TEP proteins are localized to the surface of trap cells, we hypothesized that TEP may be important for trap function,” they write in their paper. study Recently published in PLoS Biology. “addition Nematode…This will lead to immediate capture. ”
As the fungus spends more effort creating traps and forming worm glue, activities that are not actually involved in the process are deprioritized.Fragments of DNA that are usually useful A. oligospora Digested carcasses were downregulated, meaning that gene activity on these segments was reduced in response to the nematode-sensing fungus.When an insect approaches A. oligospora, This fungus showed upregulation of genes that produce proteases, enzymes that break down proteins.
I can’t get out
Still other genes showed no changes in activity until the worms were captured.one time Nematode I fell into the trap of A. oligospora After applying a sticky web of hyphae, the researchers noticed an increase in the production of a protein that weakens the prey. These proteins can manipulate prey cells to change their function, potentially providing a way for pathogens to invade and take over. The fungus then uses proteases to digest the nematodes stuck in the hyphae.
A. oligospora There are over 400 genes that encode proteins that control interactions with other organisms.. When the fungi became carnivorous with the introduction of nematodes, more than half of them began to behave differently.These proteins become weaker Nematode through various mechanisms. For example, some of them fight off antimicrobial peptides produced by nematodes.
The glue synthesized by this fungus is currently thought to be closely related to the TEP protein, and while it may not affect humans, it is useful for nematodes as an instant glue to bind mycelium to meat. let They have no way to escape being eaten alive.
The experiment may have been terrifying for the worms involved, but it was a breakthrough for Lin’s team. Now, they have identified an entirely new group of genes that perform the fungal trapping function. Their findings are: A. oligospora Because gene activity can be compared with that of other pathogenic fungi, including those that destroy crops, an improved generation of antifungal drugs may one day be inspired by this microscopic horror movie.
PLOS Biology, 2023. DOI: 10.1371/journal.pbio.3002400