Rare microbes lead scientists to discover new branch on the tree of life


Canadian researchers hold discovered a new kind of organism that’s so different from other live out things that it doesn’t fit into the plant kingdom, the animal territory, or any other kingdom used to classify known organisms.

Two species of the microscopic beings, called hemimastigotes, were found in dirt collected on a whim during a hike in Nova Scotia by Dalhousie University graduate swot Yana Eglit.

A genetic analysis shows they’re more assorted from other organisms than animals and fungi (which are in separate kingdoms) are from each other, representing a completely new part of the tree of lifestyle, Eglit and her colleagues report this week in the journal Nature.

“They sketch a major branch… that we didn’t know we were missing,” whispered Dalhousie biology professor Alastair Simpson, Eglit’s supervisor and co-author of the new observe.

“There’s nothing we know that’s closely related to them.”

In factors, he estimates you’d have to go back a billion years — about 500 million years previously the first animals arose — before you could find a common antecedent of hemimastigotes and any other known living things.

Rare microbes lead scientists to discover new branch on the tree of life

This is the part of the Rough Wilderness Trail in Nova Scotia where graduate student Yana Eglit composed some dirt that ended up containing two species of rare hemimastigotes. (Submitted by Yana Eglit)

The hemimastigotes analyzed by the Dalhousie band were found by Eglit during a spring hike with some other devotees along the Bluff Wilderness Trail outside Halifax a couple of years ago. She time again has empty sample vials in her pockets or bags, and scooped a few tablespoons of dope into one of them from the side of the trail.

Back at the lab, she soaked the smear in water, which often revives microbes that have take up dormant, waiting for the next big rainstorm. Over the next few weeks, she checked on the dish from top to bottom a microscope to see what might be swimming around.

Strange movements

Then, one day, alongside three weeks later, she saw something that caught her eye — something formed like the partially opened shell of a pistachio. It had lots of hairs, discontinued flagella, sticking out. Most known microbes with lots of flagella ploy them in co-ordinated waves, but not this one, which waved them in a innumerable random fashion. 

“It’s as if these cells never really learned that they suffer with many flagella,” Eglit said with a laugh. She had seen something with that abnormal motion once before, a few years ago, and recognized it as a rare hemimastigote.

Hemimastigotes were first digged and described in the 19th century. But at that time, no one could figure out how they fit into the evolutionary tree of dash. Consequently, they’ve been “a tantalizing mystery” to microbiologists for quite a crave time, Eglit said.

Rare microbes lead scientists to discover new branch on the tree of life

Light microscopes show the two hemimastigotes, Spironema, left side, and Hemimastix kukwesjijk, found in the same dish. (Yana Eglit/Mould)

Like animals, plants, fungi and ameobas — but unlike bacteria — hemimastigotes possess complex cells with that have mini-organs called organelles cataloguing a nucleus that holds chromosomes of DNA, making them part of the “specialization” of organisms called eukaryotes rather than bacteria or archaea.

In the matter of 10 species of hemimastigotes have been described over uncountable than 100 years. But up until now, no one had been able to do a genetic critique to see how they were related to other living things.

Realizing that she had something awfully rare and special, Eglit flagged another graduate student Gordon Lax, who specializes in genetic studies of individual microbes — a new and tricky technique — to see where they fit in the evolutionary tree. The twins dropped everything to analyze the new microbe.

Rare microbes lead scientists to discover new branch on the tree of life

The co-authors of the new study include, Heraldry sinister to right, Dalhousie University postdoctoral researcher Laura Eme, Eglit and affiliated graduate student Gordon Lax. (Michelle Léger)

New species

Eglit fall short of to see if she could find more of the creatures in the dish, and, as she was looking, she spotted another description of hemimastigote.

To our tremendous surprise, two of these extremely rarely seen structures ended up in one dish.”

There were more of the second kind, which beat back b go back out to be a new species.

The researchers named itHemimastix kukwesjijk after Kukwes, a mingy, hairy ogre from the mythology of the local Mi’kmaq people. (The affix “jijk” means “little.”)

Eglit watched carefully as it hunted. Hemimastix executes little harpoons called extrusomes to attack prey such as Spumella, a ancillary to of aquatic microbes called diatoms. It grasps its prey by curling its flagella surrounding it, bringing it to a “mouth” on one end of the cell called a capitulum “as it presumably sucks its cytoplasm out,” Eglit said.

Rare microbes lead scientists to discover new branch on the tree of life

Hemimastix kukwesjijk maintains on its prey in this microscope image. It attacks the prey with harpoon-like journals, then uses its flagella to bring the prey to its mouth, called a capitulum, and sucks out the extracts or cytoplasm. (Yana Eglit/Nature)

Once she knew what it ate, she reared its fall guy in captivity so she could also feed and breed captive Hemimastix: “We were qualified to domesticate it, in a way.”

That means scientists can now give captive specimens to other scientists to bone up on, and their rarity is not the issue it was before.

Based on the genetic analysis they’ve done so far, the Dalhousie together has determined that hemimastigotes are unique and different enough from other bodies to form their own “supra-kingdom” — a grouping so big that animals and fungi, which hold their own kingdoms, are considered similar enough to be part of the same supra-kingdom.

They are now doing a more unbroken genetic analysis of Hemimastix. That’s expected to turn up new data that resolve help scientists piece together the evolutionary history of life on Soil with more detail and more accuracy.

Eglit says it’s “darned exciting” that it’s still possible to discover something so different from all certain life on Earth.

“It really shows how much more there is out there.”

But Simpson well-known that discoveries like this one are pretty rare: “It’ll be the one time in my lifetime that we tumble to this sort of thing.”

Biology professor Alastair Simpson foretells Mainstreet host Bob Murphy how a microbe found in a dirt sample from the Bamboozle Wilderness Hiking Trail near Halifax led to the discovery of a previously little-known branch in the evolutionary ‘Tree Of Life.’ The research has just been published in the catalogue Nature. 8:23

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