Two bacteria are sitting near free-floating DNA. Suddenly, one bacterium shoots out a long appendage, latches onto a DNA fragment along with reels in its catch. which happens fast, however which’s clear: This particular organism had just gone fishing.
Biologists at Indiana University recently captured This particular maneuver on camera for the 1st time.
Researchers knew which bacteria rely on fibers called pili to capture foreign DNA. however the exact details have remained elusive because pili — more than 10,000 times thinner than human hair — are so hard to observe, said Lori Burrows, a professor of biochemistry along with biomedical sciences at McMaster University in Ontario who was not involved inside the study.
“which’s cool to actually see This particular in action,” she said.
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We typically think of genes as passed down vertically, by parent to offspring. however there are also processes called horizontal gene transfer, in which DNA moves laterally between organisms which are not parent along with child.
Natural transformation is actually one example, along with which’s an important way in which bacteria, which typically reproduce asexually, introduce variation along with brand new traits into their genetic code, said Ankur Dalia, an assistant professor of biology along with an author of the brand new paper.
The process has mesmerized biologists since 1928, when a British bacteriologist named Frederick Griffith stumbled across which while searching for a pneumonia vaccine.
To his amazement, he discovered which if he injected a heat-killed, virulent strain of Streptococcus pneumoniae, followed by a live, nonvirulent strain, bacteria which were normally innocuous would likely somehow become pathogenic.
A “transforming principle” had to be at play, he declared.
Sixteen years later, scientists showed which the transforming principle was in fact a molecule called DNA, providing one of the first clues which DNA carried genetic material.
When bacteria die, their DNA becomes up for grabs by various other microbes. Often, This particular process is actually bad news for humans. Through natural transformation, bacteria can gain the ability to degrade compounds like pesticides, become better at infecting hosts along with evolve antibiotic resistance.
In their study, Dr. Dalia along with his colleagues used a custom fluorescent dying process created by Courtney Ellison, a graduate student, along with Yves Brun, a biology professor, to visualize natural transformation in Vibrio cholera, the bacterium which causes cholera.
Ms. Ellison recounted dashing into Dr. Dalia’s lab along with blurting “you need to follow me right currently” after she became the first person to directly witness the behavior.
inside the wild, V. cholerae engage in natural transformation when they land on a piece of chitin, a major ingredient in insect along with crustacean shells, along which has a rich source of nutrients.
“which’s exactly the kind of environment various other bacteria would likely be latching onto,” along with therefore a Great site for DNA swapping, Dr. Dalia said.
When the researchers induced This particular behavior inside the lab, they were able to discern brand new details about how V. cholerae latch onto DNA at the tip of their pili, fold along with thread the DNA through a tiny surface pore along with then pull which into their bodies using a special ratcheting mechanism.
Pili in V. cholerae can stretch about as far as the length of the bacteria. The organisms make one or two pili a minute, extending along with retracting the appendages with proteins which quickly build the pili up along with then tear them back down.
Earlier reporting on what’s happening at the cellular level
The study is actually a reminder which even single-celled organisms can operate in sophisticated ways.
These bacteria are actually acting “like fishermen,” Ms. Ellison said.
Her team believes many aspects of This particular maneuver are shared among various other microbes, though more studies are needed. Eventually, the work could lead to brand new strategies for fighting antibiotic resistance.