Credit: La Trobe University

A team of scientists from La Trobe University has shown a protein found in a tobacco plant has the potential to fight life threatening infectious diseases.

The scientific discovery, published in the prestigious journal Nature Communications could lead to the development of a new class of antibiotics and meet the challenge of rising antibiotic resistance.

Dr Mark Hulett and Dr Marc Kvansakul from the La Trobe Institute for Molecular Science said their team had demonstrated the peptide NaD1 found in the flowers of the ornamental tobacco plant Nicotiana alata has infection-busting qualities.

“Infectious diseases are a major global health problem, accounting for more than one in eight deaths and mortality rates are predicted to skyrocket over the next 30 years,” Dr Hulett said.

“Antibiotic resistance at the current rate will eventually lead to the exhaustion of effective long-term drug options. It’s imperative we develop new antibiotic treatments.”

Using the power of the Australian Synchrotron, the team led by Dr Hulett and Dr Kvansakul have shown in atomic detail how the tobacco plant peptide can target and destroy the micro-organism responsible for a dangerous fungal infection.

The peptide perforates the parachute-like outer layer of Candida albicans cells, ripping them apart and causing them to explode and die. 

“They act in a different way to existing antibiotics and allow us to explore new ways of fighting infections.

“It’s an exciting discovery that could be harnessed to develop a new class of life-saving antimicrobial therapy to treat a range of infectious diseases, including multi-drug-resistant golden staph, and viral infections such as HIV, Zika virus, Dengue and Murray River Encephalitis.”

In 2014, Dr Hulett and Dr Kvansakul found NaD1 could also be effective in killing cancer cells.

Background

Candida albicans is responsible for life-threatening infections in immune-compromised patients, including those diagnosed with cancer and transplant recipients. There are limited effective antibiotics available to treat the infection.

Nicotiana alata flowers naturally produce potent anti-fungal molecules for protection against disease. The plant is related, but different, to tobacco plants grown for commercial use.

DOI: 10.1038/s41467-018-04434-y

 

Today the Australian Synchrotron joins the world in celebrating the International Day of Light 2018

This global initiative provides an annual focal point for the continued appreciation of light and the role it plays in science, culture and art, education, and sustainable development, and in fields as diverse as medicine, communications, and energy. The broad theme of light allows many different sectors of society worldwide to participate in activities that demonstrates how science, technology, art and culture can help achieve the goals of UNESCO – education, equality, and peace.

 

 

 

Experiments using X-rays on two beamlines at the Australian Synchrotron have helped characterise a new class of single atom catalysts (SACs) supported on carbon nanotubes that exhibit outstanding electrochemical reduction of CO2 to CO. A weight loading of 20 wt% for the new class, nickel single atom nitrogen doped carbon nanotubes (NiSA-N-CNTs), is believed to be the highest metal loading for SACs reported to date. 

Single atoms of nickel, cobalt and iron were supported on nitrogen doped carbon nanotubes via a one-pot pyrolysis method and compared in the study. 

A large international collaboration, led by Prof San Ping Jiang, Deputy Director of the Fuels and Energy Technology Institute at the Curtin University of Technology and associates from the Department of Chemical Engineering, have developed a new synthesis and development process for nitrogen-doped carbon nanotubes with a nickel ligand that demonstrate high catalytic activity.

The study was published in Advanced Materials and featured on the inside cover of the publication.

Dr Bernt Johannessen, instrument scientist on the X-ray absorption spectroscopy (XAS) beamline at the Australian Synchrotron was a co-author on the paper, which also included lead investigators from Curtin University of Technology and collaborators at the University of Western Australia, Institute of Metal Research (China), Oak Ridge National Laboratory (US), University of the Sunshine Coast, University of Queensland, Tsinghua University (China) and King Abdulaziz University (Saudi Arabia). Technical support and advice on the soft X-ray spectroscopy experiments was provided by Australian Synchrotron instrument scientist Dr Bruce Cowie. 

“The whole idea behind the approach is that the smaller particles you have, the more catalytically active they are. As you go to a nanoparticle size, you see catalytic activity increase. And if you take that to the extreme, you are looking at single metal atoms anchored on a supporting substrate of carbon,” said Johannessen.

“Because surface atoms behave differently to bulk or other atoms, XAS was used to verify there were in fact single atoms and the position of those nickel atoms relative to other atoms. We were able to determine bond lengths and coordination numbers.” 

The adding or subtracting single atoms from a particle opens up the possibility of tuning its properties.

The challenge has been to keep the metal atoms, which provide a strong metal support bond, from interacting with each other and aggregating because of their higher surface energy.

The investigators overcame this by developing a multistep method to synthesise atomically dispersed nickel atoms on nitrogen doped CNTs that included decomposing the precursor solution at high temperature.

The X-ray absorption near edge structure spectroscopy (XANES) measurements at the Australian Synchrotron provided supporting evidence of the electrochemical efficiency of NiSA-N-CNTs.  The results suggested that the Ni-N species are the active centres for the reduction reaction of CO2 to CO.  The single nickel atoms are held by  coordinating nitrogen atoms in the N- doped carbon nanotube structure and this helps stabilise the structure from metal aggregation.

The NiSA-N-CNTs also demonstrated a higher turnover frequency than other nitrogen doped CNTs. The data confirmed there was no obvious aggregation or breakdown of nickel and also revealed the structural durability of the NiSA-N-CNTs as electrocatalysts.

A number of other techniques and simulations were undertaken as part of materials characterisation and to confirm the CO2 reaction reduction. 

The new class of SACs has tremendous potential with promising applications in the areas of electrocatalysis and catalysts for energy conversion as well as other uses.   

DOI:10.1002/adma.201706287