Nuclear fusion reactions in the sun are the source of heat and light we receive on Earth. These reactions release a massive amount of cosmic radiation—including X-rays and gamma rays—and charged particles that can be harmful for any living organisms.
Life on Earth has been protected thanks to a magnetic field that forces charged particles to bounce from pole to pole as well as an atmosphere that filters harmful radiation.
During space travel, however, it is a different situation. To find out what happens in a cell when traveling in outer space, scientists are sending baker’s yeast to the moon as part of NASA’s Artemis 1 mission.
Cosmic radiation can damage cell DNA, significantly increasing human risk of neurodegenerative disorders and fatal diseases, like cancer. Because the International Space Station (ISS) is located in one of two of Earth’s Van Allen radiation belts—which provides a safe zone—astronauts are not exposed too much. Astronauts in the ISS experience microgravity, however, which is another stress that can dramatically change cell physiology.
As NASA is planning to send astronauts to the moon, and later on to Mars, these environmental stresses become more challenging.
The unit in the left will go to Lunar orbit while the right one is the backup, just in case I trip while holding it pic.twitter.com/QavR1OpzyW
— Luis Zea (@SpaceLuisZea) August 14, 2022
The most common strategy to protect astronauts from the negative effects of cosmic rays is to physically shield them using state-of-the-art materials.
Lessons from hibernation
Several studies show that hibernators are more resistant to high doses of radiation, and some scholars have suggested the use of “synthetic or induced torpor” during space missions to protect astronauts.
Another way to protect life from cosmic rays is studying extremophiles—organisms that can remarkably tolerate environmental stresses. Tardigrades, for instance, are micro-animals that have shown an astonishing resistance to a number of stresses, including harmful radiation. This unusual sturdiness stems from a class of proteins known as “tardigrade-specific proteins.”
Under the supervision of molecular biologist Corey Nislow, I use baker’s yeast, Saccharomyces cerevisiae, to study cosmic DNA damage stress. We are participating in NASA’s Artemis 1 mission, where our collection of yeast cells will travel to the moon and back in the Orion spacecraft for 42 days.
This collection contains about 6,000 bar-coded strains of yeast, where in each strain, one gene is deleted. When exposed to the environment in space, those strains would begin to lag if deletion of a specific gene affects cell growth and replication.
My primary project at Nislow lab is genetically engineering yeast cells to make them express tardigrade-specific proteins. We can then study how those proteins can alter the physiology of cells and their resistance to environmental stresses—most importantly radiation—with the hope that such information would come in handy when scientists try to engineer mammals with these proteins.
When the mission is completed and we receive our samples back, using the barcodes, the number of each strain could be counted to identify genes and gene pathways essential for surviving damage induced by cosmic radiation.
A model organism
Yeast has long served as a “model organism” in DNA damage studies, which means there is solid background knowledge about the mechanisms in yeast that respond to DNA-damaging agents. Most of the yeast genes playing roles in DNA damage response have been well studied.
Despite the differences in genetic complexity between yeast and humans, the function of most genes involved in DNA replication and DNA damage response have remained so conserved between the two that we can obtain a great deal of information about human cells’ DNA damage response by studying yeast.
Furthermore, the simplicity of yeast cells compared to human cells (yeast has 6,000 genes while we have more than 20,000 genes) allows us to draw more solid conclusions.
And in yeast studies, it is possible to automate the whole process of feeding the cells and stopping their growth in an electronic apparatus the size of a shoe box, whereas culturing mammalian cells requires more room in the spacecraft and far more complex machinery.
Such studies are essential to understand how astronauts’ bodies can cope with long-term space missions, and to develop effective countermeasures. Once we identify the genes playing key roles in surviving cosmic radiation and microgravity, we’d be able to look for drugs or treatments that could help boost the cells’ durability to withstand such stresses.
We could then test them in other models (such as mice) before actually applying them to astronauts. This knowledge might also be potentially useful for growing plants beyond Earth.
Studying yeast DNA in space may help protect astronauts from cosmic radiation (2022, October 3)
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In Photos: A Full ‘Cold Moon’ Occults Mars On A Rare And Auspicious Night For Crewed Spaceflight – Forbes
That a full “Cold Moon” could “occult” a planet isn’t particularly rare, but the coincidences piled-up this week to make this event rather special—and a spellbinding view for sky-watchers.
You see, Mars wasn’t just a dot in the sky that disappeared for a few minutes. Mars is this week at its biggest, brightest and best. The red planet is an “opposition,” something that happens only every 26 months and see our faster-moving planet precisely between it and the Sun.
So on the night of Wednesday, December 7, 2022 a full Moon—having recently risen in the east in a blaze of orange—blotted-out a super-bright Mars for up to an hour it was the undoubted astronomical event of the year.
Sky-watchers saw the bright red planet disappear behind the limb of the full Moon—something that took about a minute—before reappearing on the opposite side an hour or so later. Most of North America, northern Mexico, Europe and northern Africa saw the event. A prime-time evening event on December 7 for North America, Europe and Africa saw it as a pre-dawn event on December 8.
It all happened while Mars was in the in the constellation of Taurus, “the bull” with the red planet shining at a magnitude of -1.9. Astrophotographers capturing the event included Tom Williams, John Krauss and Andrew McCarthy.
If Mars being occulted at almost the exact moment it biggest, brightest and best since 2022 and until 2025 wasn’t enough there were plenty of other coincidences that added to the event’s appeal.
It was exactly 50 years since the night-launch of the Apollo 17 mission, the final crewed mission to land humans on the Moon. On December 7, 1972 astronauts Gene Cernan, Harrison Schmitt and Ronald Evans (as well as five live mice) left Kennedy Space Center atop a Saturn V rocket, with Cernan and Schmitt spent three days on the lunar surface at Taurus–Littrow.
On December 13 Cernan stepped back inside the lunar module with the words “As we leave the Moon at Taurus–Littrow, we leave as we came and, God willing, as we shall return, with peace and hope for all mankind. Godspeed the crew of Apollo 17.”
That notable anniversary was given an a layer of meaning because as the Moon was being observed occulting Mars—a target for a crewed mission by NASA perhaps in the 2030s or 2040s—a human-rated NASA spacecraft had just passed within just 21 miles of the lunar surface.
Designed for crewed trips to the Moon and Mars, Orion has, since later November, held the record for the farthest human-rated spacecraft to travel from Earth. Its Artemis I mission has been uncrewed, but its next mission—Artemis II —will take astronauts beyond the Moon, probably in 2025.
Orion will splashdown in the Pacific Ocean on December 11, but before that happens, it’s worth taking some time to look at Mars as the Moon drifts away.
With Mars at opposition it’s at its biggest, brightest and best as it rises in the east after dark, so it’s the perfect time to put a small telescope on the red planet to glimpse its redness and, if you’re lucky, its polar ice caps.
Wishing you clear skies and wide eyes.
One Great Shot: Bucktoothed Bumpheads on the Great Barrier Reef – Hakai Magazine
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When I set out to photograph bumphead parrotfish on a three-week dive trip to the northern reaches of Australia’s Great Barrier Reef in the winter of 2021, I had a specific goal in mind: I wanted to see a school of these strange animals swimming together.
There are so many weird and wonderful ocean-dwelling creatures, but this particular parrotfish species stands alone with its bizarre overbite, formidable size, prominent forehead, and tendency to travel in large groups. Bumpheads can grow to more than a meter long and about 46 kilograms—about the same weight as the average adult chimpanzee—making them the largest parrotfish and one of the world’s biggest reef fish. They also play an important role in the ecosystem: with their beaklike teeth, they munch algae off corals. In the process, they swallow other reef material and excrete it as sand.
One morning, on a pre-sunrise dive, I descended toward a reef where other divers had spotted bumpheads, hoping for my chance. Luck was on my side—it wasn’t long before I found a cluster of about 40 individuals huddled near the coral. The fish appeared to be completely still above a small bommie (reef) and were packed so tightly that their bodies were touching one another. When I edged closer, the parrotfish squeezed together even more, monitoring my every move. Reef fish are notoriously skittish, but this school stayed put while I took a picture.
The underwater world is full of fascinating species. Photographing them in their habitat is both challenging and rewarding, and I love sharing these moments with others.
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Josh Blank “One Great Shot: Bucktoothed Bumpheads on the Great Barrier Reef,” Hakai Magazine, Dec 9, 2022, accessed December 9th, 2022, https://hakaimagazine.com/videos-visuals/one-great-shot-bucktoothed-bumpheads-on-the-great-barrier-reef/.
New branch on tree of life includes ‘lions of the microbial world’
There’s a new branch on the tree of life and it’s made up of predators that nibble their prey to death.
These microbial predators fall into two groups, one of which researchers have dubbed “nibblerids” because they, well, nibble chunks off their prey using tooth-like structures. The other group, nebulids, eat their prey whole. And both comprise a new ancient branch on the tree of life called “Provora,” according to a paper published today in Nature.
Like lions, cheetahs, and more familiar predators, these microbes are numerically rare but important to the ecosystem, says senior author Dr. Patrick Keeling, professor in the UBC department of botany. “Imagine if you were an alien and sampled the Serengeti: you would get a lot of plants and maybe a gazelle, but no lions. But lions do matter, even if they are rare. These are lions of the microbial world.”
Using water samples from marine habitats around the world, including the coral reefs of Curaçao, sediment from the Black and Red seas, and water from the northeast Pacific and Arctic oceans, the researchers discovered new microbes. “I noticed that in some water samples there were tiny organisms with two flagella, or tails, that convulsively spun in place or swam very quickly. Thus began my hunt for these microbes,” said first author Dr. Denis Tikhonenkov, senior researcher at the Institute for Biology of Inland Waters of the Russian Academy of Sciences.
Dr. Tikhonenkov, a long-time collaborator of the UBC co-authors, noticed that in samples where these microbes were present, almost all others disappeared after one to two days. They were being eaten. Dr. Tikhonenkov fed the voracious predators with pre-grown peaceful protozoa, cultivating the organisms in order to study their DNA.
“In the taxonomy of living organisms, we often use the gene ’18S rRNA’ to describe genetic difference. For example, humans differ from guinea pigs in this gene by only six nucleotides. We were surprised to find that these predatory microbes differ by 170 to 180 nucleotides in the 18S rRNA gene from every other living thing on Earth. It became clear that we had discovered something completely new and amazing,” Dr. Tikhonenkov said.
New branch of life
On the tree of life, the animal kingdom would be a twig growing from one of the boughs called “domains,” the highest category of life. But sitting under domains, and above kingdoms, are branches of creatures that biologists have taken to calling “supergroups.” About five to seven have been found, with the most recent in 2018 — until now.
Understanding more about these potentially undiscovered branches of life helps us understand the foundations of the living world and just how evolution works.
“Ignoring microbial ecosystems, like we often do, is like having a house that needs repair and just redecorating the kitchen, but ignoring the roof or the foundations,” said Dr. Keeling. “This is an ancient branch of the tree of life that is roughly as diverse as the animal and fungi kingdoms combined, and no one knew it was there.”
The researchers plan to sequence whole genomes of the organisms, as well as build 3D reconstructions of the cells, in order to learn about their molecular organization, structure and eating habits.
Culturing the microbial predators was no mean feat, since they require a mini-ecosystem with their food and their food’s food just to survive in the lab. A difficult process in itself, the cultures were initially grown in Canada and Russia, and both COVID and Russia’s war with Ukraine prevented Russian scientists from visiting the lab in Canada in recent years, slowing down the collaboration.
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