Decoded: How malaria parasites invade cells

Melbourne, June 28: In a significant step towards developing a new vaccine for malaria, scientists have for the first time unveiled an atomic- scale blueprint of how the parasite invades human cells.

Using the Nobel Prizewinning technology cryoEM ( cryo- electron microscopy), the researchers mapped the previously hidden first contact between Plasmodium vivax malaria parasites and young red blood cells they invade to begin the parasites' spread throughout the body.

The study, published in the journal Nature, solves the mystery of the molecular machinery the parasite uses to latch on to red blood cells.

This essential step in the malaria lifecycle is the beginning of the classical symptoms associated with malaria — fever, chills, malaise, diarrhoea and vomiting — which can last weeks or even longer.

Earlier this year, the team discovered P vivax parasites use the human transferrin receptor to gain access to red blood cells.

Using cryo- EM technology, the team was able to overcome previous technical challenges to visualise the interaction at an atomic level.

“We’ve now mapped, down to the atomic level, exactly how the parasite interacts with the human transferrin receptor,” said Wai- Hong Tham, an associate ◗ ◗ professor at Walter and Eliza Hall Institute in Australia.

“This is critical for taking our original finding to the next stage — developing potential new antimalarial drugs and vaccines. Cryo- EM is really opening doors for researchers to visualise structures that were previously too large and complex to ‘ solve’ before,” Tham said.

P vivax is the most widespread malaria parasite worldwide. Due to its propensity to ‘ hide’ undetected, it is also the number one parasite responsible for recurrent malaria infections. Washington, June 28: Scientists found that large, carbon- rich organic molecules are ejected from cracks in the icy surface of Saturn’s moon Enceladus, indicating it satisfies all of the basic requirements for life.

Researchers, who used data from the Nasa’s Cassini spacecraft, think chemical reactions between the moon's rocky core and warm water from its subsurface ocean are linked to these complex molecules.

“We are, yet again, blown away by Enceladus. Previously we’d only identified the simplest organic molecules containing a few carbon atoms, but even that was very intriguing,” said Christopher Glein, a space scientist from Southwest Research Institute in the US.

“Now we’ve found organic molecules with masses above 200 atomic mass units. That's over ten times heavier than methane,” said Glein.

“With complex organic molecules emanating from its liquid water ocean, this moon is the only body besides Earth known to simultaneously satisfy all of the basic requirements for life as we know it,” he said.

Prior to its deorbit in September of 2017, Cassini sampled the plume of material emerging from the subsurface of Enceladus.

The Cosmic Dust Analyser ( CDA) and the SwRI- led Ion and Neutral Mass Spectrometer ( INMS) made measurements

both within the plume and Saturn’s Ering, which is formed by plume ice grains escaping Enceladus’ gravity.

“Even after its end, the Cassini spacecraft continues to teach us about the potential of Enceladus to advance the field of astrobiology in an ocean world,” Glein said.

During Cassini's close flyby of Enceladus on in 2015, researchers detected molecular hydrogen as the spacecraft flew through the plume.

Previous flybys provided

evidence for a global subsurface ocean residing above a rocky core.

Molecular hydrogen in the plume is thought to form by the geochemical interaction between water and rocks in hydrothermal environments.

“Hydrogen provides a source of chemical energy supporting microbes that live in the Earth's oceans near hydrothermal vents,” said Hunter Waite, from Southwest Research Institute.

“The paper’s also have great findings significance