Structural insights into tiny bacterial harpoons

Structural insights into tiny bacterial harpoons

Bacteria produce complex nano-harpoons on their cell surface. One of their functions is to harpoon and inject toxins into cells that are close by. Producing such a complex weapon requires lots of different moving components that scientists are still trying to understand. Researchers from the University of Sheffield have been using some of Diamond’s crystallography beamlines to understand a particularly enigmatic piece of this tiny puzzle. The team led by David Rice and Mark Thomas worked on a protein component of the harpoon called TssA which they already knew was an integral piece of the machinery. However, unlike the other components of the harpoon, there are distinct variants of the TssA protein that contain radically different amino acid sequences at one end of the protein. The team showed that the structures of the variable region of two different TssA subunits were completely unrelated and they could assemble into distinctly different multisubunit complexes in terms of their size and geometry. This begged the question as to how different bacteria could use this protein with different structures to produce a harpoon with the same function across all species. They found that despite these differences, there was a very specific conserved region at the other end of the protein. They hypothesise that the conserved region is the part that does the work and helps the harpoon to function whereas the variable region acts as a scaffold. They used I02, I03 and I24 in their study and plan to do follow up work using X-ray crystallography and Cryo-EM such as those at the eBIC centre at Diamond. The research was published in Nature Communications.

>Read more on the Diamond Light Source website

Image: Macromolecular Crystallography (MX) at Diamond reveals the shape and arrangement of biological molecules at atomic resolution, knowledge of which provides a highly accurate insight into function. 

SESAME fully powered by renewable energy

SESAME fully powered by renewable energy

SESAME becomes the world’s first large accelerator complex to be fully powered by renewable energy.

Today (26 February 2019), a ceremony was held to mark the official inauguration of the solar power plant of SESAME (Synchrotron-light for Experimental Science and Applications in the Middle East).
Constructed on grounds next to JAEC (Jordan Atomic Energy Commission) that is located some 30kms from SESAME, electricity from the solar power plant will be supplied by an on-grid photovoltaic system having a total power capacity of 6.48 MW, which will amply satisfy SESAME’s needs for several years.
Thanks to this power plant SESAME is now not only the first synchrotron light facility in the region, but also the world’s first large accelerator complex to be fully powered by renewable energy. “As in the case of all accelerators, SESAME is  in dire need of energy, and as the number of its users increases so will its electricity bill” said the Director of SESAME, Khaled Toukan. “Given the very high cost of electricity in Jordan, with this solar power plant the Centre becomes sustainable” he continued to say.
The power plant, which uses monocrystalline solar panels, was built by the Jordanian company Kawar Energy under the supervision of the consultancy firm Consolidated Consultants Group representing the owner, SESAME. Power from the solar power plant will be transmitted to the grid through the wheeling mechanism by JEPCO (Jordan Electric Power Company). The power that the solar power plant sends to the grid will be accounted for to the credit of SESAME.

>Read more on the SESAME website

Image: SESAME’s solar power plant.
Credit: SESAME.

Meteorites suggest galvanic origins for martian organic carbon

Meteorites suggest galvanic origins for martian organic carbon

The nature of carbon on Mars has been the subject of intense research since NASA’s Viking-era missions in the 1970s, due to the link between organic (carbon-containing) molecules and the detection of extraterrestrial life. Analyses of Martian meteorites marked the first confirmation that macromolecular carbon (MMC)—large chains of carbon and hydrogen—are a common occurrence in Mars rocks. More recently, researchers have applied the lessons taken from studies of meteorites to the data being gathered by the Curiosity rover, finding similar MMC signatures on Mars itself. Now, the central question is “what is the synthesis mechanism of this abiotic organic carbon?”

>Read more about on the Advanced Light Source website

Image: A high-resolution transmission electron micrograph (scale bar = 50 nm) of a grain from a Martian meteorite. Reminiscent of a long dinner fork, organic carbon layers were found between the intact “tines.” This texture was created when the volcanic minerals of the Martian rock interacted with a salty brine and became the anode and cathode of a naturally occurring battery in a corrosion reaction. This reaction would then have enough energy—under certain conditions—to synthesize organic carbon.
Credit: Andrew Steele

Urea susbstitutes noble metal catalysts

Urea susbstitutes noble metal catalysts

… for the photodegradation of organic polluants.

A new laser-based technique developed by the Institute of Materials Science (ICMAB-CSIC) uses urea, a common substance in the chemical industry and a low-cost alternative to noble metal co-catalyst, to enable a more efficient, one-step production of hybrid graphene-based organic-inorganic composite layers for environmental remediation, photodegradation of antibiotic contaminants from wastewater. The composition and chemical bonds of the urea-enriched thin layers were studied in detail using synchrotron light at the ALBA Synchrotron.
Human activity is increasing the amount of pollutants in water and air, as well as in all sorts of materials at home and work place. The existence of antibiotic contamination is undeniably one of the most threatening challenges to date, at a time when antibiotic-resistant bacteria has already been flagged as the next world-wide pandemic crisis.
Semiconductor photocatalysts have long been investigated for environmental remediation because they can degrade or mineralize a wide range of organic contaminants as well as pathogens. Research focuses on addressing some drawbacks that prevent their use on a large scale. On the one hand, many photocatalysts are activated only by UV radiation which represents solely a small fraction of the total available solar emission. On the other hand, the recombination of the photogenerated  electron-hole pairs that enable the decomposition of the pollutant is usually faster than the oxidation reactions that cause the degradation of organic molecules. As a consequence, noble metal co-catalysts acting as electron scavengers, such as gold or platinum, are needed in the process.

Image: Researchers Ángel Pérez  del Pino and Enikö György from the ICMAB-CSIC together with Ibraheem Yousef, scientists responsible of MIRAS beamline at ALBA.
Watching molecules in a light-triggered catalyst ring ‘like an ensemble of bells’

Watching molecules in a light-triggered catalyst ring ‘like an ensemble of bells’

A better understanding of these systems will aid in developing next-generation energy technologies.

Photocatalysts ­– materials that trigger chemical reactions when hit by light – are important in a number of natural and industrial processes, from producing hydrogen for fuel to enabling photosynthesis.
Now an international team has used an X-ray laser at the Department of Energy’s SLAC National Accelerator Laboratory to get an incredibly detailed look at what happens to the structure of a model photocatalyst when it absorbs light.
The researchers used extremely fast laser pulses to watch the structure change and see the molecules vibrating, ringing “like an ensemble of bells,” says lead author Kristoffer Haldrup, a senior scientist at Technical University of Denmark (DTU). This study paves the way for deeper investigation into these processes, which could help in the design of better catalysts for splitting water into hydrogen and oxygen for next-generation energy technologies.
“If we can understand such processes, then we can apply that understanding to developing molecular systems that do tricks like that with very high efficiency,” Haldrup says.

>Read more on the Linac Coherent Light Source at SLAC website

Image: When photocatalyst molecules absorb light, they start vibrating in a coordinated way, like an ensemble of bells. Capturing this response is a critical step towards understanding how to design molecules for the efficient transformation of light energy to high-value chemicals.
Credit: Gregory Stewart/SLAC National Accelerator Laboratory

Water is more homogeneous than expected

Water is more homogeneous than expected

In order to explain the known anomalies in water, some researchers assume that water consists of a mixture of two phases even under ambient conditions.

However, new X-ray spectroscopic analyses at BESSY II, ESRF and Swiss Light Source show that this is not the case. At room temperature and normal pressure, the water molecules form a fluctuating network with an average of 1.74 ± 2.1% donor and acceptor hydrogen bridge bonds per molecule each, allowing tetrahedral coordination between close neighbours.
Water at ambient conditions is the matrix of life and chemistry and behaves anomalously in many of its properties. Since Wilhelm Conrad Röntgen, two distinct separate phases have been argued to coexist in liquid water, competing with the other view of a single-phase liquid in a fluctuating hydrogen bonding network – the continuous distribution model. Over time, X-ray spectroscopic methods have repeatedly been interpreted in support of Röntgen’s postulate.

>Read more on the BESSY II at HZB website

Image: Water molecules are excited with X-ray light (blue). From the emitted light (purple) information on H-bonds can be obtained.
Credit: T. Splettstoesser/HZB

Encapsulation of drugs for new cancer treatments

Encapsulation of drugs for new cancer treatments

Research develops hydrogel from silk protein with potential application in photodynamic therapy

Cancer is a set of diseases characterized by uncontrolled multiplication of cells. One of the main methods for treating this disease is chemotherapy, which uses drugs to block the growth of those cells or to destroy them. In this way, most drugs used interfere with mitosis, the cellular mechanism by which new cells are produced. Therefore, both cancerous and healthy cells are affected, leading to several side effects.
Worldwide, considerable effort has been directed at developing new methods that act directly on the target of treatment. This is the case of so-called photodynamic therapy (PDT), a minimally invasive therapeutic procedure that selectively acts on malignant cells.
The procedure involves the administration of a light-sensitive substance, called a photosensitizing agent. When irradiated at specific wavelengths, the photosensitizer releases oxygen in reactive chemical forms that promote the death of malignant cells, infectious agents and the removal of burns.

>Read more on the Brazilian Synchrotron Light Laboratory (LNLS) website

Spin-momentum locking in cuprate high-temperature superconductors

Spin-momentum locking in cuprate high-temperature superconductors

The results open a new chapter in the mystery of high-temperature superconductors, suggesting that new, unexplored interactions and mechanisms might be at play.

In the world of superconductors, “high temperature” means that the material can conduct electricity without resistance at temperatures higher than expected, but still far below room temperature. Within this special class of high-temperature superconductors (HTSCs), cuprates—consisting of superconducting CuO2 layers separated by spacer layers—are some of the best performers, generating interest in these materials for potential use in super-efficient electrical wires that can carry power without any loss of electron momentum.

A new spin on cuprate HTSCs

Two kinds of electron interactions have been known to give rise to novel properties in new materials, including superconductors. Scientists who study cuprate superconductors have focused on just one of those interactions: electron correlation—electrons interacting with each other. The other kind of electron interaction found in exotic materials is spin-orbit coupling—the way in which an electron’s magnetic moment interacts with atoms in the material.

>Read more on the Advanced Light Source website

Image: Chris Jozwiak, Alessandra Lanzara, Kenneth Gotlieb, and Chiu-Yun Lin.
Credit: Peter DaSilva/Berkeley Lab

Superferromagnetism with electric-field induced strain

Superferromagnetism with electric-field induced strain

Data storage in today’s magnetic media is very energy consuming. Combination of novel materials and the coupling between their properties could reduce the energy needed to control magnetic memories thus contributing to a smaller carbon footprint of the IT sector. Now an international team led by HZB has observed at the HZB lightsource BESSY II a new phenomenon in iron nanograins: whereas normally the magnetic moments of the iron grains are disordered with respect each other at room temperature, this can be changed by applying an electric field: This field induces locally a strain on the system leading to the formation of a so-called superferromagnetic ordered state.
Switching magnetic domains in magnetic memories requires normally magnetic fields which are generated by electrical currents, hence requiring large amounts of electrical power. Now, teams from France, Spain and Germany have demonstrated the feasibility of another approach at the nanoscale: “We can induce magnetic order on a small region of our sample by employing a small electric field instead of using magnetic fields”, Dr. Sergio Valencia, HZB, points out.

>Read more on the Bessy II at HZB website

Image: The cones represents the magnetization of the nanoparticles. In the absence of electric field (strain-free state) the size and separation between particles leads to a random orientation of their magnetization, known as superparamagnetism
Credit: HZB

First commissioning results for insertion devices published

First commissioning results for insertion devices published

The intense X-ray light for each of the MAX IV beamlines is generated when fast electrons fly through an array of magnets, placed in a so-called insertion device.

In a recent report, our insertion device team present the commissioning results for the first nine of these beamline specific instruments.
At synchrotrons like MAX IV, we accelerate electrons to velocities close to the speed of light. The electrons are injected into storage rings where they travel turn after turn inside a vacuum tube, guided by the strong forces of hundreds of carefully tuned magnets. At certain places along the electron path, the magnets are arranged in arrays called insertion devices that make the electrons wiggle from side to side as they fly through. When the electrons perform this motion, they emit energy in the form of intense X-rays. Each beamline needs its dedicated insertion device, built to produce X-rays optimised for the measurement techniques performed there.
The insertion device team have now published the first commissioning results. At the time the report was written, twelve insertion devices were installed, and nine successfully commissioned to deliver according to specifications. Six of them have been built in-house, and two are transferred from the old MAX-lab and refurbished. The remaining insertion devices come from Hitachi and our French synchrotron colleague SOLEIL.

>Read more on the MAX IV Laboratory website

Mine tailings dumped into the sea analysed with synchrotron light

Mine tailings dumped into the sea analysed with synchrotron light

The case of Portmán Bay, at the Spanish Mediterranean coast, is one of the most extreme cases in Europe causing great impact on the marine ecosystem by disposal of mine tailings.

For more than 40 years, 60 million tonnes of mine waste were dumped directly into the sea, resulting from the open pit mining that took place in Sierra Minera in Cartagena. As a consequence, the Bay was literally filled with metal-rich artificial soil. Since 2014, a research group from the University of Barcelona (UB) has been studying Portmán Bay. Now, they have analysed samples of these sediments at ALBA because with synchrotron light they can obtain unprecedented information about the heavy metals contamination, such as arsenic.

Very few people know about Portmán Bay, where took place one of the most extreme cases of coastal ecological impact by mine activity in Europe. Figures speak for itself: the mining company Peñarroya dumped more than 60 million tonnes of mine waste into the sea through a 2km-long pipeline located at the west part of the bay. Over the years, the bay became totally filled with a mountain of artificial sediment. The shoreline moved 600m seaward and the trace of the pollution reached 12km out to sea.

>Read more on the ALBA website

Image: Miquel Canals putting sample supports, which were specifically designed and printed with 3D technology at ALBA, at the CLAESS beamline to be analysed with synchrotron light; with Carlo Marini, beamline scientist and Andrea Baza, PhD student from UB.

Illuminating a key industrial process

Illuminating a key industrial process

Results of research carried out at the U.S. Department of Energy’s (DOE’s) Advanced Photon Source (APS) may pave the way to improvements in industrial processes based on solvent extraction, which is used in the mining and refinement of technologically important rare earths. The results were published in the journal Physical Review Letters.
Rare earths such as lanthanides, which are elements in the range of atomic number 57 to 71, are not actually rare. They exist in large quantities in the world, but are only found in the form of trace amounts in rocks. Since rare earths are important for a variety of applications (e.g., electronics) their extraction is a major mining-related industry.
A common process by which rare earths are extracted involves dissolving rocks in acids, then shaking up the solution with an organic solvent and a surfactant. Under the right conditions, the desired ions move out of the aqueous phase and into the organic solvent.  This is known as “liquid-liquid extraction” or “solvent extraction,” and is conducted on a large scale by the mining industry. This process also separates heavier lanthanides from lighter lanthanides present in the same solution, because the heavier lanthanides separate more easily. While this fact is known and exploited in industrial separations processes, the nanoscale mechanisms of the separation process are not well understood.

>Read more on the Advanced Photon Source

Image: (a ) Schematic of system studied; positively charged lanthanide ions (blue circles) dissolve in the water, while the negatively charged surfactant molecules (purple) float on the water surface. (b) Data showing how density of ions at the surfactant surface jumps as the concentration of ions in the bulk water increases (Er=erbium, a heavier lanthanide, Nd=neodymium, a lighter lanthanide). The lines thru data are predictions from computer simulations. From M. Miller et al., Phys. Rev. Lett. 122, 058001 (2019).

The ALBA synchrotron and Portugal boost their scientific collaboration

The ALBA synchrotron and Portugal boost their scientific collaboration

Science ministers from Portugal and Spain have visited ALBA, motivated by a collaboration agreement that promotes the Portuguese scientific community using the ALBA Synchrotron and also includes a training program for Portuguese postdoctoral researchers at ALBA.

On 11th February 2019, at the ALBA Synchrotron facility, an agreement has been signed to promote scientific collaboration between Spain and Portugal. The agreement has been signed by Caterina Biscari, director of ALBA, and Paulo Ferrão, president of the Fundação para a Ciência e a Tecnologia (FCT), under the auspices of Pedro Duque, minister of Science, Innovation and Universities of the Spanish Government, Manuel Heitor, minister of Science Technology and Higher Education of Portugal, and Àngels Chacón, regional minister of Business and Knowledge of the Catalan Government and current chair of the ALBA Rector Council.

The Portuguese scientific community has been using the ALBA Synchrotron since the beginning of its operation in 2012. Nowadays, Portugal is the 5th country that performs more experiments at ALBA, after Germany, France, Italy and the United Kingdom. They have obtained 60% of requested beamtime and have carried out experiments mainly in biology, protein crystallography and materials science.

>Read more on the ALBA website

Image: Images of the signing agreement ceremony, held at the ALBA Synchrotron. From left to right, Caterina Biscari, director of the ALBA Synchrotron, Àngels Chacón, regional minister of Business and Knowledge of the Catalan government, Pedro Duque, minister of Science, Innovation and Universities of the Spanish Government, Manuel Heitor, minister of Science Technology and Higher Education of Portugal, and Paulo Ferrão, president of the Fundação para a Ciência e a Tecnologia (FCT). In the last picture, members of the ALBA Synchrotron management, Joan Gómez Pallarés, General director of Research from the Catalan government, and Ramon Pascual, honorary president of ALBA.

2 for the price of 1: how double ionization becomes an efficient process

2 for the price of 1: how double ionization becomes an efficient process

Double ionization is a unique mechanism where two electrons are simultaneously emitted from an atom or molecule. Typically, it’s a very weak process occurring only a few percent of the time compared to single ionization where only one electron is emitted. This is due to double ionization requiring the correlated action of two electrons hit by an energetic photon or particle. However, in a recent experiment, is has been shown that double ionization doesn’t necessarily need to be a minor effect and can even be the primary ionization mechanism.
The enhancement is likely due to double ionization proceeding through a new type of energy transfer process termed double intermolecular Coulombic decay, or dICD, for short. To experimentally observe this mechanism, dimers consisting of two alkali metal atoms were attached to the surface of helium nanodroplets. The dICD process, schematically shown in Fig. 1, occurs through an electronically excited helium atom (red), produced by synchrotron radiation, interacting with the neighboring alkali dimer (blue and white) resulting in energy transfer and double ionization. To distinguish dICD from other processes, the kinetic energies of the emitted electrons were measured in coincidence with their alkali ion counterparts.

>Read more on the Elettra website

Image: schematic view of double Intermolecular Coulombic decay (dICd).

Women in science, or welcome to everyday life at the ESRF

Women in science, or welcome to everyday life at the ESRF

The 11th February, it is the International Day of Women and Girls in Science.

Today, like every other day at the ESRF, women participate in enabling the scientific progress that takes place in our institute. Meet Isabelle, Sandrine, Marie, Anne-Lise and Blanka, five of our women engineers.

Today, their work is closely related to the Extremely Brilliant Source, or EBS, the world’s first high-energy 4th generation synchrotron under construction at the ESRF. The inside of the storage ring tunnel is unrecognisable. In the short space of time since dismantling started in January, cables and cooling circuits have been disconnected and removed, and the girders and vacuum chambers lifted out. It’s a busy scene and the hundreds of different tasks involved in the dismantling is organised with almost military precision. The woman conducting the troops is Isabelle Leconte, a job she shares with colleague Pascal Renaud.

Isabelle was originally trained in chemical engineering before specialising in vacuum and cryogenic techniques. She joined the ESRF vacuum group in 1991. After 20 years developing her skills in this area, she moved to the operation group to coordinate the maintenance works during shutdown periods and follow-up machine operation and reliability. Since October last year, she has been assigned 100% to the dismantling of EBS.

>Read more on the ESRF website

Image: Marie Spitoni prepares the alignment tools on the pre-mounted girders for EBS.
Credit: ESRF/S. Candé