Researchers at the University of Cambridge and the University of Technology Sydney’s ithree institute have just published a paper in the journal Nature, illuminating some of evolution’s early steps 2.5 billion years ago. “Archaea and bacteria joined forces early in evolution, resulting in all other complex life we see around us today,” says Iain Duggin, a researcher at the ithree institute.
Dr. Duggin and his team studied a strain of salt-tolerant archaea from the Dead Sea. “Contrary to its name, the place is actually teeming with life,” he laughs.
They were looking for similarities between proteins produced by eukaryotes and archaea. “We were retracing steps taken by evolution,” Dr. Duggin says. “We wanted to know why the function of certain proteins was conserved.”
The team identified and then deleted individual genes one by one, and observed what happened. “It’s reverse genetics,” Duggin says.
They soon noticed that some genes affected the microbe’s ability to control its shape by changing from a disc to a tube. But Dr. Duggin wanted to dig deeper and document the physical changes taking place inside the microbe.
His archaea were tiny, no more than 2 microns across, 20 times smaller than the width of a human hair. Their innards are basically invisible. The team attacked the problem with the Delta Vision OMX (opens an external site) super-resolution microscope from GE Healthcare Life Sciences (opens an external site).
The device can observe living organisms in 3D even beyond Ernst Abbe’s diffraction barrier (opens an external site), which for a long time stood as the final frontier for microscopic resolution. “The microscope allowed us to see inside the walls,” Dr. Duggin says. “We were able to resolve details we couldn’t see before.”
The device can observe living organisms in 3D even beyond Ernst Abbe’s diffraction barrier (opens an external site), which for a long time stood as the final frontier for microscopic resolution. “The microscope allowed us to see inside the walls,” Dr. Duggin says. “We were able to resolve details we couldn’t see before.”
Read the full article at the GE Reports website (opens an external site)
Super-resolution microscopy (3D-SIM) illuminates the CetZ protein in archaeal cells. The CetZ protein concentrates in areas on the envelope of the cell, revealing its outline. The cells are approximately 2 microns wide, yet the location of CetZ at different regions on the cell envelop can be resolved with remarkable clarity compared with diffraction-limited microscopy. Image credit: Dr. Iain Duggin