These Tiny Organisms Live In Water, Never Age, And Can Grow Two Heads

abstract reflection in water ripples
Oleksii Sergieiev - stock.adobe.com - illustrative purposes only - pictured above is an abstract reflection on ripples of water

Meet the hydra: a tiny, unassuming organism that lives in the water with a superpower that seems to go beyond its abilities. The creature is best known for its regeneration capabilities.

Since most of their body cells are stem cells, they can keep dividing and transforming themselves into any of their body’s cell types. They also never appear to age and may even be immortal.

The hydra is a small, invertebrate, predatory animal. It is tubular and measures up to 10 millimeters in length, consisting of a head that’s mostly a mouth, a single adhesive foot, and tentacles. You can think of it as kind of like a skinny sea anemone.

They are part of the Cnidaria group, which includes jellyfish and corals. They prey on large water fleas and small fish fry, engulfing their victims while they’re still alive.

In a new study, a team of researchers from Israel and Germany explored how certain elements and external forces can affect the hydra’s morphology. They wanted to improve scientific understanding of the organism’s biology and its ability to regenerate.

Morphogenesis is a process that causes a cell, tissue, or organism to develop its shape. The researchers confined hydra into a glass tube with narrow cylindrical channels to see what the constrained external environment would do to the organism’s form, features, and structure.

Hydra have parallel actomyosin fibers that contract. They regenerate when their tissue segments are aligned with the inherited body axis of the parent.

The team developed a method of regenerating hydra on an axis that did not align with the parallel fibers. The hydra was introduced into the glass tube and a soft gel was carefully inserted into the channels in the tube.

The soft gel reduced the movement of the tissue by about 20 to 50 cells, so it was required to unfold and regenerate into an elongated shape. After some time, the regenerating tissue formed a mouth and tentacles as the body became narrower than the tube and detached itself from the tube’s walls.

abstract reflection in water ripples

Oleksii Sergieiev – stock.adobe.com – illustrative purposes only – pictured above is an abstract reflection on ripples of water

The constraint that was imposed on the hydra tissue affects the hydra’s patterns of mechanical stress and the frequency of muscle contractions.

The researchers found that when the animals were confined lengthwise, the result was a regeneration of two heads and often more than one foot.

The discovery calls back to Greek mythology, in which the Hydra was a poisonous serpent with many heads and the power to regenerate. When one of the monster’s heads was cut off, two more would grow in its place.

Real hydra behave in very similar ways, but their immortality and regeneration are obviously due to biological processes, not magic.

The details of the study were published in the journal PRX Life.

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