“Bacteria that fix nitrogen only do so when they sense that there is very little nitrogen available in their environment,” says Professor Ray Dixon (Project Leader at the JIC. “Normally the genes for nitrogen fixation are locked off and only unlocked and used when nitrogen levels in the environment fall. We have discovered a key piece of biochemistry that allows us to better understand how the lock operates and so may allow us to alter how it works”.
The bacterium Azotobacter vinelandii is able to fix atmospheric nitrogen when available nitrogen in its environment falls below a threshold level. Nitrogen fixation requires a great deal of energy and so the genes that carry out nitrogen fixation (so called nif genes) are tightly regulated and switched off when not required.
The nif genes are regulated by the action of two proteins, called NifL and NifA. NifA stimulates the activity of nif genes, while NifL normally binds to NifA and renders it inactive. Thus whether the nif genes are active or not depends on the interaction between these two proteins. Both proteins are sensitive to biochemical signals that occur in the bacterial cell when conditions are right for nitrogen fixation. The proteins’ physical shape and structure alters in response to these signals and this affects their ability to bind to one another. The result is that, when conditions are right for nitrogen fixation, NifA is released from the grip of NifL and is then able to stimulate the activity of the nif genes and so switches on nitrogen fixation by the cell.
Water forms 'spine of hydration' around DNA, group finds
26.05.2017 | Cornell University
How herpesviruses win the footrace against the immune system
26.05.2017 | Helmholtz-Zentrum für Infektionsforschung
Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.
Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
26.05.2017 | Life Sciences
26.05.2017 | Life Sciences
26.05.2017 | Physics and Astronomy