Slime Molds Can Remember Things Without a Brain

A picture taken on October 16, 2019 at the Parc Zoologique de
Paris shows a Physarum Polycephalum better known as a “Blob.”STEPHANE
DE SAKUTIN | AFP | Getty Images
A picture taken on October 16, 2019 at the Parc Zoologique de Paris shows a Physarum Polycephalum better known as a “Blob.”STEPHANE DE SAKUTIN | AFP | Getty Images
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Slime Molds Can Remember Things Without a Brain

A picture taken on October 16, 2019 at the Parc Zoologique de
Paris shows a Physarum Polycephalum better known as a “Blob.”STEPHANE
DE SAKUTIN | AFP | Getty Images
A picture taken on October 16, 2019 at the Parc Zoologique de Paris shows a Physarum Polycephalum better known as a “Blob.”STEPHANE DE SAKUTIN | AFP | Getty Images

A recent German study found that the slime mold - known as Physarum polycephalum or The Blob - seems to remember where it previously found sources of food even without a brain or nervous system.

P. polycephalum is one of the most peculiar forms of life on earth. It is not plant, animal, nor fungus, but a species of slime mold which lives in dark forests and enjoys damp and cool environments.

The creature wanders over dead plants with a significant speed eating all fungi, bacteria, and decomposed materials it may find in its way.

Early in its life cycle, P. polycephalum exists as a single cell with a single nucleus, but later it merges with other cells to form a huge single cell that looks like a yellow pool of mud.

Similar to the invincible creatures featured in The Blob thriller, P. polycephalum can reassemble its parts even after being ripped in pieces.

In 2000, Japanese researcher Toshiyuki Nakagaki discovered that P. polycephalum was capable of solving a simple maze to reach a food source.

Biological physicists Mirna Kramar and Karen Alim of the Max Planck Institute in Germany have discovered that this brainless, neuronless creature uses the very architecture of its body to store memories about where it has previously found food.

The body of this creature is composed of a complicated network of connected tubes. During a study that will be published on March 9, in the PNAS journal, the biological physicists found that when P. polycephalum discovers a source of food, it releases a chemical that locally softens the tube wall at the site of the food.

This then triggers the tubes to dilate, becoming wider, to expedite flow within the slime mold to the site. When it found and eaten a nutritious meal, those thick tubes remain in place so that it can quickly return to the site if food were to reappear.

P. polycephalum can reabsorb parts of its body if it stretches out exploratory tubes into a region that is inhospitable, or contains nothing of interest.

"This is not utterly dissimilar to how the human brain works. In this case, synapses, which send information between neurons, strengthen when we learn and grow stronger the more we use them, but can grow weaker if we don't - vaguely similar to the slime mold's tubes, which will grow thicker at sites of interest, but will die off or be reabsorbed if their presence is no longer useful to the organism," said researcher Karen Alim in a report published on March 1, on the Science Alert website.



Bacteria Cancels Water Shows at Japan's World Expo

A photo taken on April shows a general view of the waterfront area of the World Expo, that has suspended shows because of high levels of bacteria. Richard A. Brooks / AFP/File
A photo taken on April shows a general view of the waterfront area of the World Expo, that has suspended shows because of high levels of bacteria. Richard A. Brooks / AFP/File
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Bacteria Cancels Water Shows at Japan's World Expo

A photo taken on April shows a general view of the waterfront area of the World Expo, that has suspended shows because of high levels of bacteria. Richard A. Brooks / AFP/File
A photo taken on April shows a general view of the waterfront area of the World Expo, that has suspended shows because of high levels of bacteria. Richard A. Brooks / AFP/File

The discovery of high levels of bacteria has led the World Expo in Japan's Osaka to suspend daily water shows and use of a shallow play pool, organizers said.

It comes after visitors also complained that swarms of tiny flying insects had invaded the vast waterfront site where Expo 2025 runs until mid-October.

Nearly six million people have visited exhibits from more than 160 countries, regions and organizations since it opened in April.

Although polls showed that public enthusiasm for the Expo was lukewarm before its opening, organizers say crowds have been growing, especially in recent weeks, said AFP.

But concerns were raised over environmental conditions at the reclaimed island site in Osaka Bay, which was once a landfill.

Organizers said Thursday that high levels of legionella bacteria had forced them to close an area with shallow water where visitors, including children, could cool off.

That followed a statement released Wednesday saying daily fountain shows with music and lights at an artificial pond had been suspended for the same reason.

They said they were cleaning the affected areas, adding that a decision would come on Friday on whether the shows could resume.

Days before the Expo opened, a level of methane gas high enough to potentially ignite a fire was detected at the site.

More recently, organizers sprayed insecticide to deter swarms of non-biting midges bothering guests.

Also known as a World's Fair, the Expo phenomenon, which brought the Eiffel Tower to Paris, began with London's 1851 Crystal Palace exhibition.

It is now held every five years in different global locations.