Still, bacteria and another class of microorganisms called archaea (first discovered in extreme environments such as deep-sea volcanic vents) manage just fine, thank you, in part because they have a built-in defense system that helps protect them from many viruses and other invaders.
A team of scientists led by researchers at the University of Georgia has now discovered how this bacterial defense system works, and it could lead to new classes of targeted antibiotics, new tools to study gene function in microorganisms and more stable bacterial cultures used by food and biotechnology industries to make products such as yogurt and cheese.
The research was published today in the journal Cell.
"Understanding how bacteria defend themselves gives us important information that can be used to weaken bacteria that are harmful and strengthen bacteria that are helpful," said Michael Terns, a professor of biochemistry and molecular biology in UGA's Franklin College of Arts and Sciences. "We also hope to exploit this knowledge to develop new tools to speed research on microorganisms."
Other authors on the Cell paper include Rebecca Terns, a senior research scientist in biochemistry and molecular biology at UGA; Caryn Hale, a graduate student in the Terns lab at UGA; Lance Wells, an assistant professor of biochemistry and molecular biology and Georgia Cancer Coalition Scholar at UGA and his graduate student Peng Zhao; and research associate Sara Olson, assistant professor Michael Duff and associate professor Brenton Graveley of the University of Connecticut Health Center.
The system, whose mechanism of action was uncovered in the Terns lab (Michael and Rebecca Terns are a husband-wife team), involves a "dynamic duo" made up of a bacterial RNA that recognizes and physically attaches itself to a viral target molecule, and partner proteins that cut up the target, thereby "silencing" the would-be cell killer.
The invader surveillance component of the dynamic duo (an RNA with a viral recognition sequence) comes from sites in the genomes of bacteria and archaea, known technically as "clustered regularly interspaced short palindromic repeats" or more familiarly called CRISPRs. (A palindrome is a word or sentence that reads the same forward and backward.) CRISPR RNAs don't work alone in fighting invaders, though.
Their partners in invader defense are Cas proteins that arise from a suite of genes called "CRISPR-associated" or Cas genes. Together, they form the "CRISPR-Cas system," and the new paper describes this dynamic duo and how they protect bacteria from viruses.
"You can look at one as a police dog that tracks down and latches onto an invader, and the other as a police officer that follows along and `silences' the offender," said Rebecca Terns. "It functions like our own immune system, constantly watching for and neutralizing intruders. But the surveillance is done by tiny CRISPR RNAs rather than antibodies."
What the team discovered was that a particular complex of CRISPR RNAs and a subset of the Cas proteins termed the RAMP module recognizes and destroys invader RNAs that it encounters.
"This work has uncovered intriguing parallels between the bacterial CRISPR-Cas system and the human immune system, suggesting a novel way to target disease-causing bacteria," said Laurie Tompkins, Ph.D., who oversees genetic mechanisms grants at the National Institutes of Health's National Institute of General Medical Sciences. "It may be possible to turn CRISPR-Cas into a suicide machine, killing pathogenic bacteria by an attack on their own molecules, similar to the self-destruction seen in human autoimmune diseases."
Understanding how the system silences invaders opens up opportunities to exploit it. So far, CRISPRs have been found in about half of the bacterial genomes that have been mapped or sequenced and in nearly all sequenced archaeal genomes. Such pervasiveness indicates that an ability to manipulate the CRISPR-Cas system could yield a broad range of applications. For example, using the knowledge that they have obtained in this work, the Terns now envision being able to design new CRISPR RNAs that will take advantage of the system to selectively cleave target RNAs in bacterial cells.
"These could target viruses that wipe out cultures of bacteria used by industry to produce enzymes," said Michael Terns, "or could target the gene products of the bacteria themselves. With this set of Cas proteins, we now know how to cut a target RNA at the site we choose."
"Believe it or not, we have only recently recognized that these microorganisms have a heritable immune system [because it is so different from our own]," added Rebecca Terns.
Remarkably, scientists are already in a position to begin to capitalize on their rapidly growing knowledge of this bacterial immune system.
Phil Williams | EurekAlert!
Programming cells with computer-like logic
27.07.2017 | Wyss Institute for Biologically Inspired Engineering at Harvard
Identified the component that allows a lethal bacteria to spread resistance to antibiotics
27.07.2017 | Institute for Research in Biomedicine (IRB Barcelona)
Physicists working with researcher Oriol Romero-Isart devised a new simple scheme to theoretically generate arbitrarily short and focused electromagnetic fields. This new tool could be used for precise sensing and in microscopy.
Microwaves, heat radiation, light and X-radiation are examples for electromagnetic waves. Many applications require to focus the electromagnetic fields to...
Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers
Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...
Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.
At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...
3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects
A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...
Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.
For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...
26.07.2017 | Event News
21.07.2017 | Event News
19.07.2017 | Event News
27.07.2017 | Life Sciences
27.07.2017 | Life Sciences
27.07.2017 | Health and Medicine