Brought to you by Newscorp Australia

No microscope required for record-breaking mangrove bacteria

AFP, June 29, 2022 7:00PM Kids News

Print Article

A sampling sites among the mangroves of the French Caribbean archipelago of Guadeloupe, where the giant bacteria Thiomargarita magnifica was found. Picture: Pierre-Yves Pascal/Lawrence Berkeley National Laboratory/AFP media_cameraA sampling sites among the mangroves of the French Caribbean archipelago of Guadeloupe, where the giant bacteria Thiomargarita magnifica was found. Picture: Pierre-Yves Pascal/Lawrence Berkeley National Laboratory/AFP

science

Reading level: orange

You can see it with the naked eye and pick it up with a pair of tweezers – not bad for a single bacteria*.

Scientists say they have discovered the world’s largest variety in the mangroves* of Guadeloupe, putting its puny peers to shame.

Bacteria is the planet’s oldest life form, essential to most living organisms* including us. But at up to 2cm in length, the “Thiomargarita magnifica” is around 5000 times bigger than most bacteria and has a more complex structure, according to a study published in the journal Science on Thursday.

media_cameraScientists say they have discovered the world’s largest variety of bacteria in the mangroves of Guadeloupe. Around 5000 times bigger than most bacteria, it also boasts a more complex structure, according to the study. Picture: Pierre-Yves Pascal/Lawrence Berkeley National Laboratory/AFP

The discovery “shakes up a lot of knowledge” in microbiology*, University of the Antilles Professor of Biology and co-author of the study Olivier Gros told AFP.

In his Pointe-a-Pitre laboratory in the Caribbean, Professor Gros marvelled at a test tube holding strands that looked like white eyelashes.

“At first I thought it was anything but a bacterium because something 2cm (in size) just couldn’t be one”, he said.

media_cameraA 3D microscope image of giant bacteria Thiomargarita magnifica. Picture: Olivier Gros/Lawrence Berkeley National Laboratory/AFP

The researcher first spotted the strange filaments* in a patch of sulphur-rich mangrove sediment back in 2009. Professor Gros’ initial assessment that it was “anything but a bacterium” was due to normal bacteria only being between 1-5 micrometers long. This species averages 10,000 micrometers (around 1cm), with some growing up to twice that length.

The largest-known bacterium until now had a maximum length around 750 micrometers.

Techniques including electronic microscopy* revealed it was a bacterial organism, but there was no guarantee it was a single cell.

media_cameraThe researchers found that the Thiomargarita magnifica belongs to a bacterial genus known to use sulfides to grow. Picture: Jean-Marie Volland/Lawrence Berkeley National Laboratory/AFP

Associate Professor and molecular biologist Silvina Gonzalez-Rizzo, from the same laboratory, found it belonged to the Thiomargarita family, a bacterial genus* known to use sulfides* to grow. Next a researcher in Paris suggested they were indeed dealing with just one cell – but a first attempt at peer review a few years later was abandoned.

“We were told, ‘This is interesting, but we lack the information to believe you’,” Professor Gros said, adding that they needed stronger images to provide proof.

media_cameraThis bacterial colossus is around 5000 times bigger than most bacteria. Picture: Olivier Gros/ Lawrence Berkeley National Laboratory/AFP

Then Dr Jean-Marie Volland studied the bacterium at the Lawrence Berkeley National Laboratory, run by the University of California.

With financial backing and access to some of the best tools in the field, Dr Volland and his colleagues began building up a picture of the colossal* bacteria.

It was clearly enormous by bacterial standards. Scaled up to human proportions, it would be like meeting someone “as tall as Mt Everest”, Dr Volland said.

Specialist 3D microscope images finally made it possible to prove that the entire filament was indeed a single cell.

media_cameraA bacterium’s DNA usually floats freely in the cell, but in this giant species, it is compacted in small compartments surrounded by a membrane. Picture: Jean-Marie Volland/Lawrence Berkeley National Laboratory/AFP

But they also helped Dr Volland make a “completely unexpected” discovery. Normally, a bacterium’s DNA floats freely in the cell. But in this giant species, it is compacted in small structures surrounded by a membrane* – DNA compartments that are “normally a feature of human, animal and plant cells, complex organisms … but not bacteria,” Dr Volland said.

Professor Gros said future research will have to determine if these characteristics are unique to Thiomargarita magnifica, or if they can be found in other species of bacteria.

GLOSSARY

  • bacteria: small, single-celled organisms found almost everywhere, vital to Earth’s ecosystems
  • mangroves: groups of trees and shrubs that live in coastal intertidal zones
  • organisms: any organic, living system that functions as an individual entity
  • microbiology: study of all living organisms too small to be visible with the naked eye
  • filaments: very thin threads or fibres of natural or artificial material
  • microscopy: using microscopes to view samples that can’t be seen with the naked eye
  • genus: class, kind, or group marked by one or more common characteristics
  • sulphide: any of three classes of chemical compounds containing the element sulphur
  • membrane: thin layer forming outer boundary of a living cell or internal cell compartment

EXTRA READING

Smelly theory behind the origin of Earth’s oxygen

Insect wings inspire food safety solution

Gut bacteria could help control allergies, asthma

QUICK QUIZ

  1. Where was the bacteria found and in what year?
  2. What is the average size of this species in micrometers?
  3. What was the maximum length of the previous largest-known bacterium?
  4. What did researchers need to provide as proof of their find?
  5. Aside from size, what is the other significance difference between this and other bacteria?

LISTEN TO THIS STORY

CLASSROOM ACTIVITIES
1. Why is it important?
Why do you think the discovery of Thiomargarita magnifica is important for scientists? Write a list of as many reasons as you can think of. Use information in the story to help you.

Time: allow 10 minutes to complete this activity
Curriculum Links: English; Science

2. Extension
Write a description of the steps, or method, that Professor Gros used to learn that his discovery was the world’s largest bacterium. Why do you think he followed these steps?

Time: allow 15 minutes to complete this activity
Curriculum Links: English; Science

VCOP ACTIVITY
I spy nouns
Nouns are places, names (of people and objects), and time (months or days of the week).

How many nouns can you find in the article?

Can you sort them into places, names and time?

Pick three nouns and add an adjective (describing word) to the nouns.

Extra Reading in science