Studying phage, a primitive class of virus that infects bacteria by injecting its genomic DNA into host cells, researchers have gained insight into the driving force behind this poorly understood injection process, which has been proposed in the past to occur through the release of pressure accumulated within the viral particle itself.
Almost all phages (also known as bacteriophages) are formed of a capsid structure, or head, in which the viral genome is packaged during morphogenesis, and a tail structure that ensures the attachment of the phage to the host bacteria. A common feature of phages is that during infection, only their genome is transferred to the bacterial hosts cytoplasm, whereas the capsid and tail remain bound to the cell surface. This situation is very different from that found in most eukaryotic viruses, including those that infect humans, in that the envelope of these viruses fuses with the host plasma membrane so that the genome is delivered without directly contacting the membrane.
Phage nucleic acid transport poses a fascinating biophysical problem: Transport is unidirectional and linear; it concerns a unique molecule the size of which may represent 50 times that of the bacterium. The driving force for DNA transport is still poorly defined. It was hypothesized that the internal pressure built during packaging of the DNA in the phage capsid was responsible for DNA ejection. This pressure results from the condensation of the DNA during morphogenesis – for example, another group recently showed that the pressure at the final stage of encapsulation for a particular bacteriophage reached a value of 60 atomospheres, which is close to ten times the pressure inside a bottle of champagne. In the new work reported this week, researchers have evaluated whether the energy thus stored is sufficient to permit phage DNA ejection, or only to initiate that process.
Embryonic development: How do limbs develop from cells?
18.05.2018 | Humboldt-Universität zu Berlin
Reading histone modifications, an oncoprotein is modified in return
18.05.2018 | American Society for Biochemistry and Molecular Biology
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.
The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...
Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.
Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...
A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.
Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
18.05.2018 | Power and Electrical Engineering
18.05.2018 | Information Technology
18.05.2018 | Information Technology