Researchers used colorful dyes to illuminate the electrical charges of Bacillus subtilis spores, as seen here, to track how the bacteria responded to pulses of nutrients. Bacteria like these become dormant to survive tough environments, but it wasn’t previously known how they sense when to wake up.
Bacteria go to extremes to handle hard times: They hunker down, building a fortress-like shell around their DNA and turning off all signs of life. And yet, when times improve, these dormant spores can rise from the seeming dead.
But “you gotta be careful when you decide to come back to life,” says Peter Setlow, a biochemist at UConn Health in Farmington. “Because if you get it wrong, you die.” How is a spore to tell?
For spores of the bacterium Bacillus subtilis , the solution is simple: It counts.
These “living rocks” sense it’s time to revive, or germinate, by essentially counting how often they encounter nutrients , researchers report in a new study in the Oct. 7 Science .
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“They appear to have literally no measurable biological activity,” says Gürol Süel, a microbiologist at the University of California, San Diego. But Süel and his colleagues knew that spores’ cores contain positively charged potassium atoms, and because these atoms can move around without the cell using energy, the team suspected that potassium could be involved in shocking the cells awake.
So the team exposed B. subtilis spores to nutrients and used colorful dyes to track the movement of potassium out of the core. With each exposure, more potassium left the core, shifting its electrical charge to be more negative. Once the spores’ cores were negatively charged enough, germination was triggered, like a champagne bottle finally popping its cork. The number of exposures it took to trigger germination varied by spore, just like some corks require more or less twisting to pop. Spores whose potassium movement was hamstrung showed limited change in electric charge and were less likely to “pop” back to life no matter how many nutrients they were exposed to, the team’s experiments showed.
Changes in the electrical charge of a cell are important across the tree of life, from determining when brain cells zip off messages to each other, to the snapping of a Venus flytrap ( SN: 10/14/20 ). Finding that spores also use electrical charges to set their wake-up calls excites Süel. “You want to find principles in biology,” he says, “processes that cross systems, that cross fields and boundaries.”
Spores are not only interesting for their unique and extreme biology, but also for practical applications. Some “can cause some rather nasty things” from food poisoning to anthrax, says Setlow, who was not involved in the study. Since spores are resistant to most antibiotics, understanding germination could lead to a way to bring them back to life in order to kill them for good.
Still, there are many unanswered questions about the “black box” of how spores start germination, like whether it’s possible for the spores to “reset” their potassium count. “We really are in the beginnings of trying to fill in that black box,” says Kaito Kikuchi, a biologist now at Reveal Biosciences in San Diego who conducted the work while at University of California, San Diego. But discovering how spores manage to track their environment while more dead than alive is an exciting start.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
Giving revamped silkworm silk a metallic bath may make the strands both strong and stiff , scientists report October 6 in Matter . Some strands were up to 70 percent stronger than silk spun by spiders, the team found.
The work is the latest in a decades-long quest to create fibers as strong, lightweight and biodegradable as spider silk. If scientists could mass-produce such material, the potential uses range from the biomedical to the athletic. Sutures, artificial ligaments and tendons — even sporting equipment could get an arachnid enhancement.
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“If you’ve got a climbing rope that weighs half of what it normally does and still has the same mechanical properties, then obviously you’re going to be a happy climber,” says Randy Lewis, a silk scientist at Utah State University in Logan who was not involved with the study.
Scrounging up enough silky material to make these super strong products has been a big hurdle. Silk from silkworms is simple to harvest, but not all that strong. And spider silk, the gold-standard for handspun strength and toughness, is not exactly easy to collect. “Unlike silkworms, spiders cannot be farmed due to their territorial and aggressive nature,” write study coauthor Zhi Lin, a structural biologist at Tianjin University in China, and colleagues.
Scientists around the world have tried to spin sturdy strands in the lab using silkworm cocoons as a starting point. The first step is to strip off the silk’s gummy outer coating. Scientists can do this by boiling the fibers in a chemical bath, but that can be like taking a hatchet to silk proteins. If the proteins get too damaged, it’s hard for scientists to respin them into high-quality strands, says Chris Holland, a materials scientist at the University of Sheffield in England who was not involved in the study.
Lin’s team tried gentler approaches, one of which used lower temperatures and a papaya enzyme, to help dissolve the silk’s coating. That mild-mannered method seemed to work. “They don’t have little itty-bitty pieces of silk protein,” Lewis says. “That’s huge because the bigger the proteins that remain, the stronger the fibers are going to be.”
After some processing steps, the researchers forced the resulting silk sludge through a tiny tube, like squeezing out toothpaste. Then, they bathed the extruded silk in a solution containing zinc and iron ions, eventually stretching the strands like taffy to make long, skinny fibers. The metal dip could be why some of the strands were so strong — Lin’s team detected zinc ions in the finished fibers. But Holland and Lewis aren’t so sure.
The team’s real innovation may be that “they’ve managed to unspin silk in a less damaging way,” Holland says. Lewis agrees. “In my mind,” he says, “that’s a major step forward.”
Meghan Rosen is a staff writer who reports on the life sciences for Science News . She earned a Ph.D. in biochemistry and molecular biology with an emphasis in biotechnology from the University of California, Davis, and later graduated from the science communication program at UC Santa Cruz.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
Evidence grows that there might not be an underground lake surrounded by shallow pools near Mars’ south polar ice cap (shown in this 2015 image from the European Space Agency’s Mars Express orbiter).
“Follow the water” has long been the mantra of scientists searching for life beyond Earth. After all, the only known cradle of life in the cosmos is the watery planet we call home. But now there’s more evidence suggesting that a potential discovery of liquid water on Mars might not be so watertight , researchers report September 26 in Nature Astronomy .
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But researchers have since proposed that those discoveries might not hold up to scrutiny. In 2021, one group suggested that clay minerals and frozen brines , rather than liquid water, might be responsible for the strong radar signals that researchers observed ( SN: 7/16/21 ). Spacecraft orbiting Mars beam radio waves toward the Red Planet and measure the timing and intensity of the reflected waves to infer what’s beneath the Martian surface.
And now another team has shown that ordinary layers of rock and ice can produce many of the same radar signals previously attributed to water. Planetary scientist Dan Lalich of Cornell University and his colleagues calculated how flat layers of bedrock, water ice and carbon dioxide ice — all known to be plentiful on Mars — reflect radio waves. “It was a pretty simple analysis,” Lalich says.
The researchers found that they could reproduce some of the anomalously strong radar signals thought to be due to liquid water. Individual radar signals from different layers of rock and ice add together when the layers are a certain thickness, Lalich says. That produces a stronger signal, which is then picked up by a spacecraft’s instruments. But those instruments can’t always tell the difference between a radio wave coming from one layer and one that’s the result of multiple layers, he says. “They look like one reflection to the radar.”
These results don’t rule out liquid water on Mars, Lalich and his colleagues acknowledge. “This is just saying that there are other options,” he says.
The new finding is “a plausible scenario,” says Aditya Khuller, a planetary scientist at Arizona State University in Tempe who was not involved in the research. But until scientists get a lot more data from the Red Planet, it’ll be difficult to know whether liquid water truly exists on Mars, Khuller says. “It’s important to be open-minded at this point.”
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
A crowd gathers to watch a fisher released into Washington state’s Mount Rainier National Park in December 2016. About 280 of these tree-climbing animals have been translocated from Canada since 2008 to help fisher populations rebound.
Holding an antenna above his head, Jeff Lewis crept through an evergreen forest in the Cascade mountains, southeast of Seattle. As he navigated fallen fir logs and dripping ferns, he heard it: a faint “beep” from a radio transmitter implanted in an animal code-named F023.
F023 is a fisher ( Pekania pennanti ), an elusive member of the weasel family that Lewis fondly describes as a “tree wolverine.” Resembling a cross between a cat and an otter, these sleek carnivores hunt in forests in Canada and parts of the northern United States. But fur trapping and habitat loss had wiped out Washington’s population by the mid-1900s.
Back in 2017 when Lewis was keeping tabs on F023, he tracked her radio signal from a plane two or three times a month, along with dozens of other recently released fishers. Come spring, he noticed that F023’s behavior was different from the others.
Her locations had been clustered close together for a few weeks, a sign that she might be “busy with babies,” says Lewis, a conservation biologist with the Washington Department of Fish and Wildlife. He and colleagues trekked into the woods to see if she had indeed given birth. If so, it would be the first wild-born fisher documented in the Cascades in at least half a century.
As the faint beeps grew louder, the biologists found a clump of fur snagged on a branch, scratch marks in the bark and — the best clue of all — fisher scat. The team rigged motion-detecting cameras to surrounding trees. A few days later, after sifting through hundreds of images of squirrels and deer, the team hit the jackpot: a grainy photo of F023 ferrying a kit down from her den high in a hemlock tree. The scientists were ecstatic.
“We’re all a bunch of little kids when it comes to getting photos like that,” Lewis says.
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This notable birth came during the second phase of a 14-year fisher reintroduction effort. After 90 fishers were released in Olympic National Park from 2008 to 2010, the project turned its focus east of Seattle, relocating 81 fishers in the South Cascades (home to Mount Rainier National Park) from 2015 to 2020, and then 89 fishers in the North Cascades from 2018 to 2020. The animals were brought in from British Columbia and Alberta. The project concluded last year, when researchers let loose the final batch of fishers.
Washington’s fisher recovery efforts relocated the animals to three regions of the state: the Olympic Peninsula west of Seattle and the North and South Cascades, a mountain range separated by Interstate 90.
Baby animals are the key measure of success for a wildlife reintroduction project. As part of Washington’s Fisher Recovery Plan, biologists set out to document newborn kits as an indicator of how fishers were faring in the three relocation regions.
Before F023’s kit was caught on camera in May 2017, biologists had already confirmed births by seven relocated females on the Olympic Peninsula, where the whole project began. Two of the seven females had four kits, “the largest litter size ever documented on the West Coast,” says Patti Happe, wildlife branch chief at Olympic National Park. Most females have one to three kits.
Lewis is often asked, why put all of this effort into restoring a critter many people have never heard of? His answer: A full array of carnivores makes the ecosystem more resilient.
Happe admits to another motive: “They’re freaking adorable — that’s partly why we’re saving them.”
Contrary to their name, fishers don’t hunt fish, though they’ll happily munch on a dead one if it’s handy. They mainly prey on small mammals, but they also eat reptiles, amphibians, insects, fruit and carrion. About a meter long, males weigh up to six kilograms, about twice as much as females. Fun facts: Females raise young high above the forest floor in hollowed-out spaces in tree trunks. Fishers can travel face-first down tree trunks by turning their hind feet 180 degrees. They have wickedly sharp teeth and partially retractable claws. And they’re incredibly agile, leaping up to two meters between branches and traveling as much as 30 kilometers in a day.
Fishers’ stubby legs and unique climbing skills make them a threat to tree-climbing porcupines. It isn’t pretty: A fisher will force the quill-covered animal down a tree and attack its face until it dies from blood loss or shock. Then the fisher neatly skins the prickly prey, eating most everything except the quills and bones.
But these fearsome predators were no match for humans. In the 1800s, trappers began targeting fishers for their fur. Soft and luxuriant, the glossy brown-gold pelts were coveted fashion accessories, selling for as much as $345 each in the 1920s. This demand meant fishers disappeared not only from Washington, but from more than a dozen states across the northern United States. Once fisher populations plummeted, porcupines ran rampant across the Great Lakes region and New England. This wreaked havoc on forests because the porcupines gobbled up tree seedlings.
Hoping to keep porcupine populations in check, private timber companies partnered with state agencies to bring fishers back to several states in the 1950s and 1960s. Thanks to these efforts and stricter trapping regulations, fishers are once again abundant in Michigan, Wisconsin, New York and Massachusetts.
But in Washington, like most of the West, fisher numbers were still slim. By the turn of the 21st century, no fisher had been sighted in the state for over three decades.
As in the Midwest and New England, private timber companies in Washington supported bringing back fishers. Although porcupines are uncommon in Washington, mountain beavers — a large, primitive rodent endemic to the Pacific Northwest — fill a similar role in Washington’s evergreen forests: They eat tree seedlings. And fishers eat them.
By 2006, the state hatched a plan to bring the animals in from Canada. “It was a big opportunity to restore a species,” Lewis says. “We can fix this.”
Like the other Canadian fishers moved to Washington, F023’s relocation story began when she walked into a box trap in British Columbia, lured by a tasty morsel of meat. The bait had been set by local trappers hired by Conservation Northwest, a nonprofit that is one of the recovery project’s three main partners, along with Washington Fish and Wildlife and the National Park Service. After veterinarians checked her health and administered vaccines and antiparasitics to help her survive in her new home, F023 received a surgically implanted radio transmitter and was driven across the border.
She was met by members of the fisher recovery team, who released her just south of Mount Rainier National Park. The forest’s towering Douglas fir, western red cedar and western hemlock trees were full of cubby holes and cavities to hide in, and the undergrowth held plenty of small mammals to eat. At the release, upward of 150 people gathered around F023’s box, part of the team’s effort to engage the public in championing fisher recovery. Everyone cheered as a child opened the door and the furry female bounded into the snowy woods, out of sight in a flash.
The team monitored each relocated fisher for up to two years to see if the project met key benchmarks of success in each of the three regions: more than 50 percent of the fishers surviving their first year, at least half establishing a home range near the release site, and a confirmed kit born to at least one female.
“We met those marks,” says Dave Werntz, science and conservation director at Conservation Northwest.
The effort may have been aided by a series of bypasses built over and under a roughly 25-kilometer stretch of Interstate 90 east of Seattle. One of these structures is the largest wildlife bridge in North America, an overpass “paved” with forest. In 2020, a remote camera caught an image of what looks like a fisher moving through one of the underpasses.
“Male fishers go on these huge walkabouts to find females,” Werntz says. While biologists assumed fishers would cross the freeway to search for mates, having photographic proof “is pretty wonderful,” he says.
Happe and others hope to also see wildlife crossings along Interstate 5 one day. The freeway, which runs north-south near the coast, is the main obstacle keeping the Olympic and Cascade populations apart, she says. “We’re all working on wildlife travel corridors and connectivity in hopes the two populations hook up.”
The majority of the initial 90 fishers relocated to the Olympic Peninsula settled nicely into their new homes, according to radio tracking. In the year following release in that location, the fisher survival rate averaged 73 percent , but varied based on the year and season they were released, as well as sex and age of the fishers.
Males fared better than females: Seventy-four percent of recorded deaths were of females, partly because they are smaller and more vulnerable to predators, such as bobcats and coyotes. Of 24 recovered carcasses where cause of death could be determined , 14 were killed by predators, seven were struck by vehicles, two drowned and one died in a leg-hold trap, Lewis, Happe and colleagues reported in the April 2022 Journal of Wildlife Management .
Because the first fishers relocated to the Olympic Peninsula were released in several locations, the animals had trouble finding mates. As a result, only a few parents sired the subsequent generations.
The researchers became concerned when they looked at the genetic diversity of fishers on the Olympic Peninsula six years post-relocation. Happe and colleagues set up 788 remote cameras and hair-snare stations: triangular cubbies open on either end with a chicken leg as bait in the middle and wire brushes protruding from either side to grab strands of fur. DNA analysis of the fur raised red flags about inbreeding , Happe and Lewis say.
“Models showed we were going to lose up to 50 percent of genetic diversity, and the population would wink out in something like 100 years,” Happe says. To expand the gene pool, the team brought 20 more fishers to the Olympic Peninsula in 2021. These animals came from Alberta whereas the founding population had hailed from British Columbia.
As the reintroduction effort moved into the Cascades, the team adapted, based on lessons learned from the Olympic Peninsula. For instance, to increase the likelihood of fishers finding each other more quickly, the animals were released at fewer sites that were closer together. The team also released the animals before January, giving females ample time to settle into a home range before the spring mating and birthing season.
As the experiment went on, more unanticipated findings popped up. Fishers released in the southern part of the Cascades were more likely to survive the first year (76 percent) than those relocated north of I-90 (40 percent), according to the final project report, released in June. Remote-camera data suggest that’s because there are less prey and slightly more predators in the North Cascades, says Tanner Humphries, community wildlife monitoring program lead for Conservation Northwest.
And in both the Cascades and the Olympic Peninsula, fishers are using different types of habitat than biologists had predicted, Happe says. The mammals — once assumed to be old-growth specialists — are using a mosaic of young and old forests. Fishers require large, old trees with cavities for denning and resting. But in younger managed forests where trees are thinned or cut, prey may be easier to come by.
Live traps in the South Cascades support that idea. Fishers’ preferred prey — snowshoe hares and mountain beavers — were most abundant in young regenerating forests. In older forests, traps detected mainly mice, voles and chipmunks , which are not substantial meals for fishers, Mitchell Parsons, a wildlife ecologist at Utah State University in Logan, reported with Lewis, Werntz and others in 2020 in Forest Ecology and Management .
After F023’s baby was caught on camera five years ago, the mother’s tracking chip degraded as designed — the hardware lasts less than two years. Since then, many more fisher kits have been born in Washington.
In fact, these furry carnivores are one of the most successfully translocated mammals in North America. According to Lewis, 41 different translocation efforts across the continent have helped fisher populations blossom. The animals now occupy 68 percent of their historical range, up from 43 percent in the mid-1900s.
With the last batch of fishers delivered to Washington in 2021, the relocation phase of the project has ended. Lewis, Happe and their partners plan to continue monitoring how these sleek tree-climbing carnivores are faring — and how the ecosystem is responding. For instance, fishers are indeed feasting on seedling-eating mountain beavers , according to research reported by Happe, Lewis and others in 2021 in Northwestern Naturalist .
Given climate change, species loss and ecosystem degradation, animals worldwide face difficult challenges. The fact that fishers are thriving once again in Washington offers hope, Lewis says.
“It’s a hard time, it’s a hard world, and this feels like something we’re doing right,” he says. “Instead of losing something, we’re getting it back.”
Brianna Randall is a freelance writer based in Missoula, Montana.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
Bull sperm that cluster together in groups of two or more swim straighter and more directly than individual sperm on their travels to fertilize a female egg cell.
S. Phuyal, S.S. Suarez and C.-K. Tung/ Frontiers in Cell and Developmental Biology 2022
Bull sperm swim more effectively when in clusters, a new study shows, potentially offering insight into fertility in humans. In simulated reproductive tracts of animals like cattle and humans, the behavior increases the chances that groups of cooperative bovine sperm will outpace meandering loners as they race to fertilize a female egg cell, physicist Chih-kuan Tung and colleagues report September 22 in Frontiers in Cell and Developmental Biology .
The benefits of clustering don’t come down to flat-out speed. “They are not faster,” says Tung, of North Carolina Agricultural and Technical State University in Greensboro. “In terms of speed, they are comparable or slower” than sperm traveling alone. Like the sperm equivalent of herds of tortoises racing individual hares, the winners are not necessarily the swiftest but rather the ones that can stay on target.
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On their own, sperm tend to follow curved paths — which is a problem, because the shortest distance between two points is a straight line. But when sperm gather in groups of two or more, they swim along straighter routes. It’s behavior that a couple of the same researchers noted in a previous study where they tracked sperm swimming in stationary fluids ( SN: 3/17/16 ). Although that might give sperm clusters an advantage, it would only help if they happen to be going the right direction. Other benefits of sperm clustering weren’t clear until the researchers developed an experimental setup that introduced flowing fluid into their experiments.
In creatures like humans and cattle, sperm make their way to the ovum by swimming against a current of mucus that streams through the cervix and away from the uterus. It’s difficult to study what benefits clustering might confer while swimming upstream inside living beings. So Tung and colleagues created an analog in their lab: a shallow, narrow, 4-centimeter-long channel filled with a thick fluid that mimics natural mucus and flows at rates the researchers could control.
Whether alone or in groups, sperm naturally tend to swim upstream. However, clusters of sperm in the experiment did a better job heading upstream into the mucus flow, while individual sperm were more likely to head off in other directions. Despite the speedier travels of some individual sperm, a poorer ability to point upstream hampered the progress of sperm loners compared with slower moving clusters.
Clusters also stayed the course in the face of rapidly flowing mucus. When the researchers turned up the flow in their apparatus, many individual sperm were washed away. Sperm clusters were much less likely to get swept downstream.
While sperm in the study were bovine, the advantages of clustering should also apply to human sperm, Tung says. Sperm of both species have similar dimensions. The swimmers typically compete to fertilize a single ovum. And unlike pigs or other animals where semen is deposited directly in the uterus, both human and bovine sperm start out in the vagina and travel through the cervix to get to the uterus.
Studying sperm in fluids that closely resemble the flowing mucus in reproductive tracts could reveal problems that don’t turn up in conventional observations of sperm swimming in stationary fluids, Tung says. “One hope is that this sort of knowledge can help us do better diagnoses” to provide clues to understand infertility in humans ( SN: 3/31/03 ).
Subjecting sperm to realistic settings in the lab may soon offer practical help for people who have trouble conceiving , says fertility researcher Christopher Barratt of the University of Dundee in Scotland, who was not affiliated with the study ( SN: 6/9/21 ).
“How a sperm cell responds to its surroundings and how that may change its behavior is a very important subject,” Barratt says. “This type of technology could be used, or adapted, to select better quality sperm,” for people in need of fertility assistance. “That would be a very big deal.”
James Riordon is a freelance science writer who covers physics, math, astronomy and occasional lifestyle stories.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
This image of the hand of an embryonic Madagascar giant day gecko, shown at 63 times magnification, displays cyan-colored nerve cells. Collagen appears yellow to orange.
Grigorii Timin and Michel Milinkovitch/University of Geneva, Nikon Small World
Life is beautiful at all scales, from big to small. Sometimes that splendor is concealed beneath literal scales.
A mesmerizing peek below the developing scales on the hand of an embryonic Madagascar giant day gecko ( Phelsuma grandis ) won first place in the 2022 Nikon Small World photomicrography competition . The winning image, stitched together from hundreds of images taken over two days with a confocal microscope, was crafted by University of Geneva researchers Grigorii Timin and Michel Milinkovitch. The pair study the genetics and physics of embryonic development.
The hand is artificially colored to show budding nerves in cyan and structures containing collagen in a range of oranges and yellows. Collagen is a building block of life, says Milinkovitch. Knowing where collagen is can help researchers better understand how bodies and tissues develop.
Tap this image and those below to enlarge
Parts of bones that have started to calcify shine brightest in the image, Timin says. Developing tendons and ligaments stretch as orange branches. Blood cells form clusters or line up inside new blood vessels at the tips of the gecko’s digits.
The image highlights beauty of all sizes, Milinkovitch says. The snapshot is “beautiful as a hand, you see this beautiful pattern of the fingers. Then you zoom, you see the spongy bones. And you zoom, you see the tendons. And you zoom, and you see the fibers that’s from the tendons. Then you zoom, and you see the blood cells.”
The gecko photo is one of 92 incredible images recognized in this year’s competition. The winners of the 48th annual contest were announced October 11. Here are some of our other favorites.
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From a distance this photograph may look like a cluster of grapes. But each orb is a sprawling clump of cells inside breast tissue.
Cancer immunologist Caleb Dawson of the Walter and Eliza Hall Institute of Medical Research in Parkville, Australia, took thousands of images using a confocal microscope to view tiny, musclelike cells that wrap around milk-producing spheres. He used dyes and antibodies to mark the cells yellow and magenta in this second-place-winning image.
The cells respond to the hormone oxytocin, Dawson says. Oxytocin is released during breastfeeding and helps squeeze milk out of the spheres, called alveoli. Such images of lactating breast tissue can help researchers figure out how immune cells keep breast tissue and the babies it can feed healthy.
Ole Bielfeldt had to be quick to capture the last gasp of an extinguished candle.
Candle wax is made of hydrogen and carbon atoms, which turn mostly into carbon dioxide when lit on fire. But not all those hydrocarbons burn, instead accumulating as soot on surfaces close to the candle. “When the flame goes out, the glowing wick has enough heat left to break up the wax molecules for a while, but not enough to burn the carbon,” says Bielfeldt, a photographer in Cologne, Germany. “So you get a trail of smoke until it cools.”
Using a fast shutter speed and a bright LED light, Bielfeldt managed to capture those unburned particles of carbon drifting away, earning sixth place.
Hidden on leaves and decaying logs in moist forests are minuscule works of art like these Lamproderma slime molds.
In the dappled sun of an October day, photographer Alison Pollack of San Anselmo, Calif., saw a sparkly leaf as she was digging through a leaf pile. After taking the leaf home and looking through a microscope, she was transfixed by the crinkly heads and iridescence of slime mold. Around 40 hours of work and 147 combined images later, Pollack had captured a striking snapshot that she likes to anthropomorphize as a nurturing relationship: parent and child, two lovers, or brother and sister. The photo earned fifth place in the contest.
Most slime molds have smooth heads, which release spores into the environment to reproduce. This pair may have dried too fast, stunting their development and leaving their heads wrinkly, Pollack says. But that’s OK, “because the texture to me is just gorgeous.”
All fear the predacious tiger beetle, especially this poor fly.
Murat Öztürk of Ankara, Turkey, nabbed 10th place in this year’s competition with an astounding — and unnerving — snapshot of a tiger beetle using its mandibles to crush a fly by its eyes.
Tiger beetles ( Cicindelinae ) sprint after their prey so quickly that the insects go temporarily blind . The photographed beetle would have stopped multiple times to orient itself to figure out where the fly was, eventually snatching its meal. Thanks to the beetle’s strong and sharp jaws, “the chances of survival of the creatures caught by this insect are very low,” Öztürk says.
In Opal Reef off the coast of Australia, some cauliflower coral ( Pocillopora verrucosa ) polyps appear green. But the same organism is transformed when viewed under a microscope in the lab.
To reveal the polyp’s individual cells, marine scientist Brett Lewis of Queensland University of Technology in Brisbane, Australia, stitched together more than 60 images taken over 36 hours. The coral naturally fluoresces a medley of blues, purples and pinks when exposed to different wavelengths of light. Algae living inside the polyp appear orange or pink, while the coral’s tissues shine blue. The image won 12th place in the competition.
One amazing thing about the photo, Lewis says, is that in some areas, algal cells shine through a light blue haze. That’s because coral tissue is transparent; algae give coral its color.
Peeks of coral’s internal makings can help scientists understand its biology, Lewis says. His work, for instance, aims to figure out how young polyps build strong foundations when they attach to a surface — an important step in building or restoring coral reefs.
Erin I. Garcia de Jesus is a staff writer at Science News . She holds a Ph.D. in microbiology from the University of Washington and a master’s in science communication from the University of California, Santa Cruz.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
