Zinc redistribution within the plant root system as a mechanism of adaptation

Researchers from the Faculty of Biology, University of Warsaw, grew tobacco plants in a transparent soil system that mimics natural conditions, allowing for a controlled heterogeneous distribution of nutrients. They discovered that when some parts of the roots had access to Zn while others did not, the Zn‑deficient roots did not show the usual Zn deficiency response. This suggested a previously unknown distribution of Zn within the root system, from “Zn‑sufficient” roots to “Zn‑deficient” ones.

To confirm that Zn was redistributed within the plant body, a collaboration with the POLYX beamline team was established to use micro X‑ray fluorescence (μXRF) imaging at the Polish National Synchrotron Radiation Center SOLARIS. This state of the art technique enabled them to visualize Zn distribution at high resolution directly in plant tissues. The analyses revealed that under uneven Zn conditions, the element accumulated evenly in the root system but, surprisingly, there was a preferential accumulation of Zn in the leaf veins, providing new insight into potential Zn distribution routes. The researchers also linked these physiological changes to the activity of key Zn transports, such as NtZIP4B (a Zn importer), NtHMA4a/b (Zn exporters), and NtNAS (a Zn chelator). Interestingly, the position of Zn in the soil—whether in upper or lower layers—affected how strongly genes coding these transporters were expressed and how much Zn reached the leaves.

Read more on the SOLARIS website

Image: The figure shows series of experiments about plants coping with uneven access to zinc in the soil. Using an innovative “transparent soil” system and micro‑XRF at SOLARIS, scientists from the University of Warsaw observed how roots transport zinc from zones with sufficient supply to zinc‑deficient parts of the root system, ensuring stable plant growth. This discovery opens new perspectives for sustainable fertilization and improving crop quality.

Zinc detected in clogged syringes

Employees of the technology transfer centre ANAXAM and researchers from the Paul Scherrer Institute PSI used the unique analytical methods available at PSI to look inside pre-filled syringes. They found that, in rare cases, zinc from the needle shield can leach into the drug solution to be injected and possibly contribute to syringe clogging.

The task which the employees of the technology transfer centre ANAXAM set themselves, together with colleagues at the Paul Scherrer Institute PSI, can be likened to looking for a needle in a haystack. They were asked by the pharmaceutical company MSD (a trade name of Merck & Co., Inc., Rahway, N.J., USA) to find out whether tiny amounts of the element zinc can get inside the needles of pre-filled syringes and, if so, where it lodges in the needles.

The background is the observation that, in rare cases, the needles of pre-filled syringes (PFS) can become blocked, for example if the syringes are not stored in a cool enough environment. This phenomenon has been known for some time and has already been studied by ANAXAM. However, what has remained unclear is exactly what triggers the blockage. One suggestion was that zinc from the needle shield – the rubber cap into which the needle is inserted when the syringe is manufactured – could leach into the drug solution to be injected, making it more viscous, which would ultimately lead to blockages. 

To investigate this theory, the team led by ANAXAM has now resorted to sophisticated methods of detection. These allowed them to look inside the blocked hypodermic needles and check whether and where zinc was present. The results have now been published in the journal Pharmaceutical Research

Convenient pre-filled syringes

Pre-filled syringes are widely available, practical and easy to use, both for healthcare professionals and for patients. The amount of solution to be injected is precisely measured, which virtually rules out dosing errors, for example. The fact that their needles can become clogged, especially when the solution to be injected is highly concentrated, is a well-known issue in the pharmaceutical industry and has also been raised during licensing applications. There have also been cases of clogged needles which have led to products being recalled. “So Merck was very interested in knowing whether zinc could in fact find its way into the needles and cause the blockage,” says Vlad Novak, project manager at ANAXAM. 

This meant that several questions had to be answered. Is there zinc inside the needle? And if so, where do they come from? What does the inside of a clogged needle look like? And is the zinc also present in the solution being injected, which could ultimately lead to the blockage?

Read more on the PSI website

Image: Employees of the technology transfer centre ANAXAM and researchers at the Paul Scherrer Institute PSI used the unique analytical methods available at PSI’s large research facilities to look inside pre-filled syringes.

Credit: © Adobe Stock

Finetuning fertilizers to boost crop yields

Worldwide, many agricultural soils are deficient in the nutrient zinc – despite the fact that farmers use fertilizers enriched with the element. This limits crop yields and reduces food quality. It’s estimated that roughly a third of the global population consume foods low in zinc, which can increase sickness and death in early childhood, as well as impaired growth and cognition.

Using the Canadian Light Source (CLS) at the University of Saskatchewan (USask), researchers from the University of Adelaide in Australia investigated how to manufacture more efficient zinc-enriched fertilizers. The HXMA beamline at CLS enabled the researchers to examine at the molecular level what happens to the water solubility of zinc (its ability to dissolve in water) when it’s added to ammonium phosphate fertilizer.

“Going in to the project, our group thought the type of zinc compound would be a good predictor of a fertilizer’s solubility” says Rodrigo da Silva, from the University of Adelaide. “However, the CLS beamline enabled us to understand that the agronomic performance cannot be predicted based on what form of zinc is present in the fertilizer granules. Instead, the pH drives the fertilizer zinc solubility and availability to the crops.”

Dr. da Silva and colleagues found that when zinc is added to phosphate fertilizer, it forms a range of different zinc phosphate compounds. However, its solubility was not related to the relative abundance of these compounds, but to fertilizer pH. This means that zinc added to more alkaline phosphate fertilizers such as diammonium phosphate will have very low solubility and hence low agronomic effectiveness for crop uptake.

Read more on CLS website

Mapping metals in feathers

Synchrotron technique promising for tracing metals in nature

University of Saskatchewan (USask) and Environment and Climate Change Canada (ECCC)  researchers have mapped metals in bird feathers, a technique that could help make environmental monitoring less destructive.

In a recent paper published in X-ray Spectrometry, researchers used the Canadian Light Source (CLS) synchrotron at USask to examine the level and distribution of zinc in feathers from birds that were fed high-zinc diets.

“The same technique could be applied to toxic metals like mercury, even at low concentrations,” says Agriculture and Agri-Food Canada scientist Fardausi Akhter. “You could just take a feather from the bird and be able to show if it was exposed to toxic metals present in the environment.”

Akhter, a toxicologist interested in applying synchrotron techniques to environmental questions, first started working on this project with Graham Fairhurst, a USask avian ecophysiologist, when they were both working as postdocs supervised by Catherine Soos. Soos is a wildlife health specialist and research scientist at ECCC, and adjunct professor at USask (Department of Veterinary Pathology, Western College of Veterinary Medicine), whose research focuses on investigating impacts of large-scale environmental changes on wildlife health. Her team often uses feathers as tools to evaluate exposure to toxic metals, and impacts of exposure on health of wild birds.  

>Read more on the Canadian Light Source website

Image: Part of the research team at CLS (left to right): Fardausi (Shathi) Akhter, Jamille McLeod (ECCC), Bruce Pauli (ECCC), Peter Blanchard (CLS), Landon McPhee (ECCC), and Catherine Soos (ECCC)

Imaging dendrite growth in zinc-air batteries

SXCT captures unprecedented detail of dendrite formation, growth and dissolution

Modern life runs on rechargeable batteries, which power all of our mobile devices and are increasingly used to power vehicles and to store energy from renewable sources. We are approaching the limits of lithium-ion battery technology in terms of maximum energy capacity, and new technologies will be needed to develop higher capacity rechargeable batteries for the future. One class of promising candidates is metal-air batteries, in particular zinc-air batteries that have a high theoretical energy density and low estimated production costs. However, zinc-air batteries present certain challenges, in key areas such as cycle life, reversibility and power density. The formation of metal dendrites as the battery charges is a common cause of failure, as dendrites can cause internal short circuits and even thermal runaway. (Thermal runaway is a sequence of exothermic reactions that take place within the battery, leading to overheating and potentially resulting in fire or an explosion. It is also a problem in lithium-ion batteries, and the subject of ongoing research.) In work recently published in Joule, a team of researchers from Imperial College, London, University College London, the University of Manchester and the Research Complex at Harwell carried out in situ experiments investigating how dendritic growth can cause irreversible capacity loss, battery degradation and eventually failure.
>Read more on the Diamond Light Source website

Image: (extract, see full image here) Single dendrite and dendritic deposits inside and on top of the separator (FIB-SEM)

A closer look of zink behaviour under extreme conditions

Researchers have explored the phase diagram of zinc under high pressure and high temperature conditions, finding evidence of a change in its structural behaviour at 10 GPa. Experiments profited from the brightness of synchrotron light at ALBA and Diamond.

These results can help to understand the processes and phenomena happening in the Earth’s interior.

The field of materials science studies the properties and processes of solids to understand and discover their performances. Synchrotron light techniques permit to analyse these materials at extreme conditions (high pressure and high temperature), getting new details and a deep knowledge of them.

Studying the melting behaviours of terrestrial elements and materials at extreme conditions, researchers can understand the phenomena taking place inside them. This information is of great value for discovering how these materials react in the inner core of Earth but also for other industrial applications. Zinc is one of the most abundant elements in Earth’s crust and is used in multiple areas such as construction, ship-building or automobile.

>Read more on the ALBA website

Figure: P-T phase diagram of zinc for P<16 GPa and T<1600K. Square data points correspond to the X-ray diffraction measurements. Solid squares are used for the low pressure hexagonal phase (hcp) and empty symbols for the high pressure hexagonal phase (hcp’). White, red and black circles are melting points from previous studies reported in the literature. The triangles are melting points obtained in the present laser-heating measurements. In the onset of the figure is shown the custom-built vacuum vessel for resistively-heated membrane-type DAC used in the experiments at the ALBA Synchrotron.