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Control of the protective shell of bacteria

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Helicobacter pylori, a stomach germ, knows how to protect itself against attacks by the immune system or by antibiotics. A research team from the University of Würzburg has succeeded in deciphering new details of this ability.

Helicobacter pylori is widespread worldwide. Experts estimate that about half of humanity carries the bacterium – preferably in the stomach. Thanks to various adaptations, Helicobacter is protected from the extremely acidic environment and is able to settle and multiply permanently in the gastric mucosa. Above all, the ability to make the structures on the surface of its envelope extremely variable helps the bacterium to hold its own in this environment, which is hostile in and of itself. It uses the same trick to hide itself from the immune system of its host.

A group of scientists from the Julius Maximilian University of Würzburg (JMU), together with collaborators at the Institut Pasteur in Paris, have now uncovered new details about how it does this. The team has succeeded in identifying a gene that is involved in the synthesis of the surface structures of the bacteria.

Furthermore, they were able to show that a small RNA can modulate the expression of this gene and thus vary the nature of the surface structures. In this way, Helicobacter pylori not only manages to escape the immune system, but also to vary its sensitivity to certain antibiotics.

Publication in Nature Communications

The researchers have now published the results of their investigations in the journal Nature Communications. Cynthia Sharma, head of the Department of Molecular Infection Biology II and spokesperson for the Center for Infection Research at JMU, is responsible for the publication.

Lipopolysaccharides (LPS): This is the technical term for these surface structures in which Sharma and her team are interested. These are compounds of fat-like (lipo) components and sugar (polysaccharide) that are found in the outer membrane of bacteria such as Helicobacter. “Helicobacter pylori produces a unique lipopolysaccharide compared to other bacteria that performs important functions in the infection process. Without this molecule, the bacterium could not colonize the human stomach or survive there permanently,” Sharma explains.

On the other hand, LPS is one of the most powerful stimulators of the immune system. For an organism to effectively fight an infection with Helicobacter, its immune cells must be able to recognize these structures. The bacteria have learned to prevent this in the course of evolution: “During an infection, many pathogens modify their LPS synthesis as well as their structure. In this way, they can escape recognition by the immune system,” says Sharma.

Widely dispersed genes

Although the central role of lipopolysaccharides in the successful infection of the host by certain bacteria is well known, the synthetic pathway of these molecules in the case of Helicobacter pylori has not yet been completely deciphered. “This could be due to the fact that the genes responsible for LPS synthesis are scattered throughout the bacterium’s genome,” Sharma suspects. Together with her team, she has now succeeded in identifying an essential protein in this process.

So-called “hypervariable simple sequence repeats (SSRs)” are one of the main sources of the changes in lipopolysaccharides. They are short DNA sequences that are randomly varied in length during cell division and influence the expression of genes. In previous work, the group was able to show that such SSRs are also targets for small regulatory RNAs (sRNAs), an important class of regulators that, for example, control gene expression under stress conditions or during infection.

Gradual resistance to antibiotics

In the study now published, the participants show that a specific sRNA with the scientific name RepG (regulator of polymeric G-repeats) in Helicobacter pylori controls the synthesis of LPS by modulating the expression of a gene that is important for this process. The interplay between the various players allows for stepwise control of LPS biosynthesis by the sRNA.

 

“In this way, regulatory RNA can fine-tune the structure of lipopolysaccharides, influencing their sensitivity to antibiotics and reducing the risk of being recognized by the host immune system.”

– Sandy Westermann, first author of the study

 

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Research in the field of organic batteries

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The so-called redox flow batteries (RFB) represent a promising concept for the storage of renewable electrical energy. In this type of battery, which is particularly suitable for stationary applications, the energy is stored in tanks with liquid electrolytes, while the power is determined by the area of the cells. RFBs based on vanadium salts as the energy carrier are particularly well developed. They are already used in numerous plants. However, vanadium also accounts for a significant proportion of the total cost of the battery, so cheaper alternatives are being sought.

One possibility is the transition from metal salts as energy carriers to organic molecules. Because of the wide variety of possible compounds, some of which can be produced from renewable raw materials, organic RFBs have been the subject of intensive research for several years. An important issue still to be resolved is the long-term stability of the organic energy carriers, which, unlike inorganic salts, can decompose during the electrochemical processes. A whole series of scientific questions also remain to be resolved with regard to the details of the processes at the carbon electrodes.

Over the next two years, Luis Fernando Arenas will be investigating organic redox flow batteries in Professor Thomas Turek’s research group at the Energy Storage Technologies Research Center (EST) of the Clausthal University of Technology in Goslar. Various projects on the development of vanadium-based RFBs have been carried out there in recent years, and the working group has extensive test facilities for measuring the performance data of RFB components such as electrodes, membranes and bipolar plates. The principles and methods developed in this work will now be applied to organic redox flow batteries.

Luis Fernando Arenas is a technical chemist who earned his master’s degree in 2013 from the University of Coahuila in Mexico. He then moved to the University of Southampton, where he obtained his PhD in 2017 in the renowned research group of Professor Frank C. Walsh with a thesis on RFB based on zinc and cerium.

Since then, he has continued as a visiting scientist at the University of Southampton and is a member of the Executive Committee of the Electrochemical Technology Group of the Society of Chemical Industry. He is also involved with the National Institute of Electricity and Clean Energy (INEEL) in Cuernavaca, Mexico, and consults for companies in the electrochemical industry, including chlor-alkali companies in Monterrey, Mexico. In 2019, he was awarded the Schwäbisch Gmünd Prize of the European Academy of Surface Technology.

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Support from the Chemical and plastics industry in the fight against marine litter

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In the middle of this week, an international ministerial conference was held to prepare a global agreement against marine litter and the pollution of the environment with plastic waste. The German Chemical Industry Association (VCI) and PlasticsEurope Deutschland (PED), the association of plastics producers, are in favor of the global effort. The conference was also convened at the initiative of Germany’s environment minister to push for a global agreement ahead of the UN Environment Assembly in spring 2022.

“Plastic waste has no place in the environment. It must be collected and recycled. A global agreement against marine litter can make a valuable contribution to this. In this way, we not only protect the oceans, but also the climate. The agreement should not focus on plastics, but on consumer goods in general that are carelessly disposed of in the environment.”

  – Ingemar Bühler, chief executive of PED

In March 2011, plastics associations set solutions against marine litter in motion with a global declaration. Currently, some 395 projects are underway or completed worldwide, including for better waste management, beach cleanups and educating local people. Innovative solutions for recycling and reuse of plastics play an important role in waste management. Therefore, Bühler points out, “Promoting innovative technologies for the circular economy should be a key concern in a global agreement. In the end, the aim must be to use waste to manufacture new products and thus conserve resources.” 

The German chemical industry also sees a great opportunity in the recycling of plastics: “Plastics are far too good to end up as waste in the environment. If they are recycled, this reduces the use of fossil raw materials and protects the climate. This is where we need to rethink in parts: That’s why we are massively pushing complementary technologies such as chemical recycling,” adds Wolfgang Große Entrup, CEO of the VCI. 

 

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Fuel cells: Mass production now possible

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In the “H2FastCell” research project, a research team from Fraunhofer IPA and the Black Forest Campus is working with an industrial consortium to develop a robotic cell for the automated high-speed assembly of fuel cell stacks. In doing so, they are laying the foundation for industrial mass production of this emission-free technology. Hydrogen will play an important role as an energy carrier. It can be produced from renewable energies in electrolysers in a CO2-neutral way and then converted into electrical energy in fuel cells. Particularly in freight transport, fuel cells can play out their advantages over battery-electric vehicles. But there are also many future areas of application for fuel cells in the stationary sector. In the production of fuel cells, efficient cycle times and absolute precision are crucial.

The major goal is to reduce manufacturing costs in order to make the use of this technology more economical. However, this can only be achieved through scaling effects, which require fully automated plants with correspondingly high capacities. At the moment, this type of production plant is not yet available on the market, and the design of the components must also continue to be optimized with regard to automation-compatible construction.

That’s why it makes sense to start looking now for ways to manufacture them in an automated way that is suitable for mass production. This is precisely what a research team from the Fraunhofer Institute for Manufacturing Engineering and Automation IPA and the Center for Digitalization, Leadership and Sustainability Black Forest (Black Forest Campus) has set out to do in the “H2FastCell” project. Together with teams from five companies, the scientists want to develop a robotic cell by 2023 that assembles the individual layers of a fuel cell in seconds and with absolute precision.

13 minutes to the finished stack

A fuel cell stack consists of stacked layers of bipolar plates, through which hydrogen and oxygen are introduced, and membrane electrode units, in which the two chemical elements react with each other. Because this reaction only produces a voltage of one volt at most, about 400 fuel cells must be stacked on top of each other for a fuel cell engine to power a truck, for example. Precision is required here. Any deviation – even in the micrometer range – can reduce the performance of the fuel cell system.

The assembly robot, which will take over the stacking of bipolar plates and membrane electrode units in alternation in the H2FastCell research project, will therefore scan the individual layers as it grips them. Since he stacks several stacks in parallel, he can spontaneously assign a layer to the stack on which the dimensions fit best. Performance degradations are thus avoided before they occur. All this is supposed to happen so fast that it will be difficult for humans to follow the individual assembly steps with the naked eye: one second per layer. A stack composed of 400 individual fuel cells would therefore be finished after only about 13 minutes. Manually, many times that time would be needed.

Prices for fuel cells could fall

“If the throughput of the stacks is increased in this way, it will lay the foundation for the industrial mass production of fuel cells. Prices would fall and the use of fuel cells in mobile heavy-duty applications would finally become competitive,” says Friedrich-Wilhelm Speckmann of the Center for Digitized Battery Cell Production at Fraunhofer IPA. He and Erwin Groß from the Corporate Strategy and Development department at Fraunhofer IPA are leading the H2FastCell research project.

Demonstrator stacking facility at the Black Forest Campus.

By summer 2023, the research team aims to have set up a demonstrator stacking facility for automated fuel cell assembly at the Schwarzwald Campus in Freudenstadt. This facility will be available to companies for further trials, feasibility studies and validations.

“With this first project, we are laying the foundation for our future research center for biointelligent hydrogen cycle management in the Black Forest. With this, we want to make hydrogen technology usable for mobile and stationary use as an energy carrier together with companies in Baden-Württemberg.”

– Stefan Bogenrieder, Managing Director of the Black Forest Campus

The H2FastCell research project started on July 26, 2021 and is scheduled to run for two years. In addition to Fraunhofer IPA and the Black Forest Campus, five companies from Baden-Württemberg are involved: the software developer ISG Industrielle Steuerungstechnik GmbH from Stuttgart, the vacuum technology manufacturer J. Schmalz GmbH from Glatten in the northern Black Forest, the sensor producer i-mation GmbH from Rottweil, the machine and plant manufacturer teamtechnik Maschinen und Anlagen GmbH from Freiberg am Neckar, and the automation engineer WEISS GmbH from Buchen in the Odenwald. The Baden-Württemberg Ministry of Economics, Labor and Tourism is funding H2FastCell with around 2.3 million euros.

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