Scientists have discovered that bacteria can reshape their DNA to survive dehydration.
The research, published today in the journal Proceedings of the Royal Society Interface, shows that bacterial DNA can change from the regular double helix – known as B-DNA, to the more compact A-DNA form, when faced with hostile conditions such as dehydration.
A-DNA (left) B-DNA (right)
Crucially, scientists have pinpointed a unique process in DNA, called the B-A-B transition, which allows it to change its structure in response to environmental change. Without impacting on the ability of the bacteria to function and reproduce, this unique structural alteration sees the B-DNA change to A-DNA, and then revert back to its original B-DNA form to ensure the bacteria survive.
Associate Professor Bayden Wood, from Monash University said the study gives vital new information on how bacteria can survive periods of time in arid environments.
“Our findings may be important in understanding how dormant bacteria that are transferred from dry surfaces may become active and reproduce in the human body,’ Associate Professor Wood said.
PhD student and first author of the paper, Donna Whelan said the most common form of DNA found in most organisms is B-DNA. However, the A-form has been thought to show protective qualities to allow bacterial spores to survive high UV exposure and other extreme environmental conditions.
“Our research, which utilised infrared light to investigate the structure of DNA inside live bacteria, demonstrates that bacteria can survive by adopting the A-DNA form after the majority of water is removed – and that really is groundbreaking,” Donna Whelan said.
The new findings build on research led by Associate Professor Wood and Donna Whelan in 2011 at the Australian Synchrotron, which indicated the same B-A-B DNA transition occurs in all cell types. Significantly, the team has now discovered this change may have a biological function in bacteria, potentially assisting them to survive dehydration.
Associate Professor Bayden Wood said the ability for DNA to transform and then change back again in human cells had puzzled scientists until now.
“In human cells the DNA is tightly bound by proteins known as histones, so the fact that it can change to a different form and then change back again is fascinating. We have no biological reason for why this DNA transition happens in human cells, but we may now understand its role in bacteria,” Associate Professor Wood said.
The interdisciplinary team at Monash investigated four species of bacteria using live cells. By carefully hydrating and dehydrating the bacteria and then analysing the cells using an infrared-based technique, which detects the vibrations of DNA, the team found all four species underwent the same B-A-B transition.
Professor Julian Rood, who coordinated the microbiology aspects of the research, said that because the majority of bacteria remained fully functional after hydration and rehydration the results suggest A-DNA may have a highly evolved protective capacity to ensure survival.
“We discovered A-DNA has an amazing ability to protect and ensure life continues even under extreme stress, in this case dehydration. In our tests, even after the majority of water was removed, A-DNA kicked in and then changed back to B-DNA to help the bacteria survive,” Professor Rood said.
The next phase of the research will see the team investigate how bacteria survive other conditions such as temperature, pH levels, oxygen, nutrients and antimicrobials and discover what role the 'clever' DNA plays under these conditions.
Lucy Handford | Eurek Alert!
Nerves control the body’s bacterial community
26.09.2017 | Christian-Albrechts-Universität zu Kiel
Ageless ears? Elderly barn owls do not become hard of hearing
26.09.2017 | Carl von Ossietzky-Universität Oldenburg
Controlling electronic current is essential to modern electronics, as data and signals are transferred by streams of electrons which are controlled at high speed. Demands on transmission speeds are also increasing as technology develops. Scientists from the Chair of Laser Physics and the Chair of Applied Physics at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have succeeded in switching on a current with a desired direction in graphene using a single laser pulse within a femtosecond ¬¬ – a femtosecond corresponds to the millionth part of a billionth of a second. This is more than a thousand times faster compared to the most efficient transistors today.
Graphene is up to the job
At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.
Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
26.09.2017 | Life Sciences
26.09.2017 | Physics and Astronomy
26.09.2017 | Information Technology