But the seven-second video, which is sped-up from 19 minutes, is real.

The hand, which would take six hours to create using conventional 3D printing methods, demonstrates what University at Buffalo engineers say is progress toward 3D-printed human tissue and organs — biotechnology that could eventually save countless lives lost due to the shortage of donor organs.

“The technology we’ve developed is 10-50 times faster than the industry standard, and it works with large sample sizes that have been very difficult to achieve previously,” says the study’s co-lead author Ruogang Zhao, PhD, associate professor of biomedical engineering.

The work is described in a study published Feb. 15 in the journal Advanced Healthcare Materials.

It centers on a 3D printing method called stereolithography and jelly-like materials known as hydrogels, which are used to create, among things, diapers, contact lenses and scaffolds in tissue engineering.

The latter application is particularly useful in 3D printing, and it’s something the research team spent a major part of its effort optimizing to achieve its incredibly fast and accurate 3D printing technique.

“Our method allows for the rapid printing of centimeter-sized hydrogel models. It signifcantly reduces part deformation and cellular injuries caused by the prolonged exposure to the environmental stresses you commonly see in conventional 3D printing methods,” says the study’s other co-lead author, Chi Zhou, PhD, associate professor of industrial and systems engineering.

Researchers say the method is particularly suitable for printing cells with embedded blood vessel networks, a nascent technology expected to be a central part of the production of 3D-printed human tissue and organs.

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Materials provided by University at Buffalo. Original written by Cory Nealon. Note: Content may be edited for style and length.

So-called gene drives, which leverage CRISPR technology to influence genetic inheritance, carry the promise of rapidly spreading specific genetic traits throughout populations of a given species. Gene-drive technologies applied in insects, for example, are being designed to halt the spread of devastating diseases such as malaria and dengue by preventing mosquito hosts from becoming infected. In agricultural fields, gene-drives are being developed to help control or eliminate economically damaging crop pests.

But along with the capacity to alter populations, concerns have been raised regarding the long-term effects of these transformative new technologies in the wild. Researchers and ethicists have voiced questions about how gene drives, once turned loose in a regional population, could be held in check if necessary.

Now, researchers at the University of California San Diego, Tata Institute for Genetics and Society (TIGS) at UC San Diego and their colleagues at UC Berkeley have developed a new method that provides more control over gene drive releases. Details of the new “split drive” are published March 5 in the journals Nature Communications and eLife.

The most common gene drives employ a two-component system that features a DNA-cutting enzyme (called Cas9) and a guide RNA (or gRNA) that targets cuts at specific sites in the genome. Following the Cas9/gRNA cut, the gene drive, along with the cargo it carries, is copied into the break site through a DNA repair process.

While classic gene drives are designed to spread autonomously, the newly developed system is designed with controls that separate the genetic implementation processes. The split-drive system consists of a non-spreadable Cas9 component inserted into one location in the genome and a second genetic element that can copy itself — along with a beneficial trait — at a separate site. When both elements are present together in an individual, an “active gene drive” is created that spreads the element carrying the beneficial trait to most of its progeny. Yet, when uncoupled, the element carrying the beneficial trait is inherited under typical generational genetics rules, or Mendelian frequencies, rather than spreading unrestrained.

As described in the Nature Communications paper, by creating slight fitness costs that eventually eliminate the Cas9 enzyme from the population, the split-drive system vastly increases control and safety of the genetic deployments.

“Studying drives in essential genes is not a novel idea, per se, but we observed that certain split situations were able to spread a cargo effectively upon a first introduction while leaving no trace of Cas9 after a few generations, as well as few mistakes in the DNA repair process that got rapidly diluted out,” said Gerard Terradas, first author in the Nature Communications paper and a postdoctoral scholar in the UC San Diego Division of Biological Sciences.

The Nature Communications paper also spells out advantages on how gene drives are perceived by the public, as efforts to alter wild populations could be flexibly designed in a variety of ways per the desired outcome.

The new split-drive system follows research announced in September in which UC San Diego researchers led the development of two new active genetics neutralizing strategies that are designed to halt or inactivate gene drives released in the wild.

“We hope that the flexible design features we have developed will be broadly applicable by enabling tailored approaches to controlling insect vectors and pests in diverse contexts,” said UC San Diego Distinguished Professor Ethan Bier, senior author of the Nature Communications study and science director for TIGS-UC San Diego.

“These seminal papers reflect a tremendous effort, and fruitful cross-UC collaborations, to demonstrate novel gene drive architectures for mitigating the formation of resistant alleles while providing a safe confinable means for modification of wild populations,” said UC San Diego Associate Professor Omar Akbari, senior author of the eLife study.

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Materials provided by University of California – San Diego. Original written by Mario Aguilera. Note: Content may be edited for style and length.

There’s a reason why egg cells, or oocytes, are so big: They need to accumulate enough nutrients to support a growing embryo after fertilization, plus mitochondria to power all of that growth. However, biologists don’t yet understand the full picture of how egg cells become so large.

A new study in fruit flies, by a team of MIT biologists and mathematicians, reveals that the process through which the oocyte grows significantly and rapidly before fertilization relies on physical phenomena analogous to the exchange of gases between balloons of different sizes. Specifically, the researchers showed that “nurse cells” surrounding the much larger oocyte dump their contents into the larger cell, just as air flows from a smaller balloon into a larger one when they are connected by small tubes in an experimental setup.

“The study shows how physics and biology come together, and how nature can use physical processes to create this robust mechanism,” says Jörn Dunkel, an MIT associate professor of physical applied mathematics. “If you want to develop as an embryo, one of the goals is to make things very reproducible, and physics provides a very robust way of achieving certain transport processes.”

Dunkel and Adam Martin, an MIT associate professor of biology, are the senior authors of the paper, which appears this week in the Proceedings of the National Academy of Sciences. The study’s lead authors are postdoc Jasmin Imran Alsous and graduate student Nicolas Romeo. Jonathan Jackson, a Harvard University graduate student, and Frank Mason, a research assistant professor at Vanderbilt University School of Medicine, are also authors of the paper.

A physical process

In female fruit flies, eggs develop within cell clusters known as cysts. An immature oocyte undergoes four cycles of cell division to produce one egg cell and 15 nurse cells. However, the cell separation is incomplete, and each cell remains connected to the others by narrow channels that act as valves that allow material to pass between cells.

Members of Martin’s lab began studying this process because of their longstanding interest in myosin, a class of proteins that can act as motors and help muscle cells contract. Imran Alsous performed high-resolution, live imaging of egg formation in fruit flies and found that myosin does indeed play a role, but only in the second phase of the transport process. During the earliest phase, the researchers were puzzled to see that the cells did not appear to be increasing their contractility at all, suggesting that a mechanism other than “squeezing” was initiating the transport.

“The two phases are strikingly obvious,” Martin says. “After we saw this, we were mystified, because there’s really not a change in myosin associated with the onset of this process, which is what we were expecting to see.”

Martin and his lab then joined forces with Dunkel, who studies the physics of soft surfaces and flowing matter. Dunkel and Romeo wondered if the cells might be behaving the same way that balloons of different sizes behave when they are connected. While one might expect that the larger balloon would leak air to the smaller until they are the same size, what actually happens is that air flows from the smaller to the larger.

This happens because the smaller balloon, which has greater curvature, experiences more surface tension, and therefore higher pressure, than the larger balloon. Air is therefore forced out of the smaller balloon and into the larger one. “It’s counterintuitive, but it’s a very robust process,” Dunkel says.

Adapting mathematical equations that had already been derived to explain this “two-balloon effect,” the researchers came up with a model that describes how cell contents are transferred from the 15 small nurse cells to the large oocyte, based on their sizes and their connections to each other. The nurse cells in the layer closest to the oocyte transfer their contents first, followed by the cells in more distant layers.

“After I spent some time building a more complicated model to explain the 16-cell problem, we realized that the simulation of the simpler 16-balloon system looked very much like the 16-cell network. It is surprising to see that such counterintuitive but mathematically simple ideas describe the process so well,” Romeo says.

The first phase of nurse cell dumping appears to coincide with when the channels connecting the cells become large enough for cytoplasm to move through them. Once the nurse cells shrink to about 25 percent of their original size, leaving them only slightly larger than their nuclei, the second phase of the process is triggered and myosin contractions force the remaining contents of the nurse cells into the egg cell.

“In the first part of the process, there’s very little squeezing going on, and the cells just shrink uniformly. Then this second process kicks in toward the end where you start to get more active squeezing, or peristalsis-like deformations of the cell, that complete the dumping process,” Martin says.

Cell cooperation

The findings demonstrate how cells can coordinate their behavior, using both biological and physical mechanisms, to bring about tissue-level behavior, Imran Alsous says.

“Here, you have several nurse cells whose job it is to nurse the future egg cell, and to do so, these cells appear to transport their contents in a coordinated and directional manner to the oocyte,” she says.

Oocyte and early embryonic development in fruit flies and other invertebrates bears some similarities to those of mammals, but it’s unknown if the same mechanism of egg cell growth might be seen in humans or other mammals, the researchers say.

“There’s evidence in mice that the oocyte develops as a cyst with other interconnected cells, and that there is some transport between them, but we don’t know if the mechanisms that we’re seeing here operate in mammals,” Martin says.

The researchers are now studying what triggers the second, myosin-powered phase of the dumping process to start. They are also investigating how changes to the original sizes of the nurse cells might affect egg formation.

The research was funded by the National Institute of General Medical Sciences, a Complex Systems Scholar Award from the James S. McDonnell Foundation, and the Robert E. Collins Distinguished Scholarship Fund.

“When it comes to wheeled vehicles on other planets, there are few first-time events that measure up in significance to that of the first drive,” said Anais Zarifian, Mars 2020 Perseverance rover mobility test bed engineer at NASA’s Jet Propulsion Laboratory in Southern California. “This was our first chance to ‘kick the tires’ and take Perseverance out for a spin. The rover’s six-wheel drive responded superbly. We are now confident our drive system is good to go, capable of taking us wherever the science leads us over the next two years.”

The drive, which lasted about 33 minutes, propelled the rover forward 13 feet (4 meters), where it then turned in place 150 degrees to the left and backed up 8 feet (2.5 meters) into its new temporary parking space. To help better understand the dynamics of a retrorocket landing on the Red Planet, engineers used Perseverance’s Navigation and Hazard Avoidance Cameras to image the spot where Perseverance touched down, dispersing Martian dust with plumes from its engines.

More Than Roving

The rover’s mobility system is not only thing getting a test drive during this period of initial checkouts. On Feb. 26 — Perseverance’s eighth Martian day, or sol, since landing — mission controllers completed a software update, replacing the computer program that helped land Perseverance with one they will rely on to investigate the planet.

More recently, the controllers checked out Perseverance’s Radar Imager for Mars’ Subsurface Experiment (RIMFAX) and Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) instruments, and deployed the Mars Environmental Dynamics Analyzer (MEDA) instrument’s two wind sensors, which extend out from the rover’s mast. Another significant milestone occurred on March 2, or Sol 12, when engineers unstowed the rover’s 7-foot-long (2-meter-long) robotic arm for the first time, flexing each of its five joints over the course of two hours.

“Tuesday’s first test of the robotic arm was a big moment for us,” said Robert Hogg, Mars 2020 Perseverance rover deputy mission manager. “That’s the main tool the science team will use to do close-up examination of the geologic features of Jezero Crater, and then we’ll drill and sample the ones they find the most interesting. When we got confirmation of the robotic arm flexing its muscles, including images of it working beautifully after its long trip to Mars — well, it made my day.”

Upcoming events and evaluations include more detailed testing and calibration of science instruments, sending the rover on longer drives, and jettisoning covers that shield both the adaptive caching assembly (part of the rover’s Sample Caching System) and the Ingenuity Mars Helicopter during landing. The experimental flight test program for the Ingenuity Mars Helicopter will also take place during the rover’s commissioning.

Through it all, the rover is sending down images from the most advanced suite of cameras ever to travel to Mars. The mission’s cameras have already sent about 7,000 images. On Earth, Perseverance’s imagery flows through the powerful Deep Space Network (DSN), managed by NASA’s Space Communications and Navigation (SCaN) program. In space, several Mars orbiters play an equally important role.

“Orbiter support for downlink of data has been a real gamechanger,” said Justin Maki, chief engineer for imaging and the imaging scientist for the Mars 2020 Perseverance rover mission at JPL. “When you see a beautiful image from Jezero, consider that it took a whole team of Martians to get it to you. Every picture from Perseverance is relayed by either the European Space Agency’s Trace Gas Orbiter, or NASA’s MAVEN, Mars Odyssey, or Mars Reconnaissance Orbiter. They are important partners in our explorations and our discoveries.”

The sheer volume of imagery and data already coming down on this mission has been a welcome bounty for Matt Wallace, who recalls waiting anxiously for the first images to trickle in during NASA’s first Mars rover mission, Sojourner, which explored Mars in 1997. On March 3, Wallace became the mission’s new project manager. He replaced John McNamee, who is stepping down as he intended, after helming the project for nearly a decade.

“John has provided unwavering support to me and every member of the project for over a decade,” said Wallace. “He has left his mark on this mission and team, and it has been my privilege to not only call him boss but also my friend.”

Touchdown Site Named

With Perseverance departing from its touchdown site, mission team scientists have memorialized the spot, informally naming it for the late science fiction author Octavia E. Butler. The groundbreaking author and Pasadena, California, native was the first African American woman to win both the Hugo Award and Nebula Award, and she was the first science fiction writer honored with a MacArthur Fellowship. The location where Perseverance began its mission on Mars now bears the name “Octavia E. Butler Landing.”

Official scientific names for places and objects throughout the solar system — including asteroids, comets, and locations on planets — are designated by the International Astronomical Union. Scientists working with NASA’s Mars rovers have traditionally given unofficial nicknames to various geological features, which they can use as references in scientific papers.

“Butler’s protagonists embody determination and inventiveness, making her a perfect fit for the Perseverance rover mission and its theme of overcoming challenges,” said Kathryn Stack Morgan, deputy project scientist for Perseverance. “Butler inspired and influenced the planetary science community and many beyond, including those typically under-represented in STEM fields.”

“I can think of no better person to mark this historic landing site than Octavia E. Butler, who not only grew up next door to JPL in Pasadena, but she also inspired millions with her visions of a science-based future,” said Thomas Zurbuchen, NASA Associate Administrator for science. “Her guiding principle, ‘When using science, do so accurately,’ is what the science team at NASA is all about. Her work continues to inspire today’s scientists and engineers across the globe — all in the name of a bolder, more equitable future for all.”

Butler, who died in 2006, authored such notable works as “Kindred,” “Bloodchild,” “Speech Sounds,” “Parable of the Sower,” “Parable of the Talents,” and the “Patternist” series. Her writing explores themes of race, gender, equality, and humanity, and her works are as relevant today as they were when originally written and published.

More About the Mission

A key objective of Perseverance’s mission on Mars is astrobiology, including the search for signs of ancient microbial life. The rover will characterize the planet’s geology and past climate, pave the way for human exploration of the Red Planet, and be the first mission to collect and cache Martian rock and regolith.

Subsequent NASA missions, in cooperation with ESA (European Space Agency), would send spacecraft to Mars to collect these sealed samples from the surface and return them to Earth for in-depth analysis.

The Mars 2020 Perseverance mission is part of NASA’s Moon to Mars exploration approach, which includes Artemis missions to the Moon that will help prepare for human exploration of the Red Planet.

JPL, which is managed for NASA by Caltech in Pasadena, built and manages operations of the Perseverance rover.

For more about Perseverance:

https://www.nasa.gov/perseverance

and

https://mars.nasa.gov/mars2020

For more information about NASA’s Mars missions, go to:

https://www.nasa.gov/mars

The group of investigators published their findings March 5 in Cell Stem Cell. This is the first time scientists have reported modifying a NG2 glia — a type of supporting cell in the central nervous system — into functional neurons after spinal cord injury, said Wei Wu, PhD, research associate in neurological surgery at IU School of Medicine and co-first author of the paper.

Wu and Xiao-Ming Xu, PhD, the Mari Hulman George Professor of Neuroscience Research at IU School of Medicine, worked on the study with a team of scientists from the University of Texas Southwestern Medical Center. Xu is also a primary member of Stark Neurosciences Research Institute, where he leads the Indiana Spinal Cord and Brain Injury Research Group.

Spinal cord injuries affect hundreds of thousands of people in the United States, with thousands more diagnosed each year. Neurons in the spinal cord don’t regenerate after injury, which typically causes a person to experience permanent physical and neurological ailments.

“Unfortunately, effective treatments for significant recovery remain to be developed,” Xu said. “We hope that this new discovery will be translated to a clinically relevant repair strategy that benefits those who suffer from a spinal cord injury.”

When the spinal cord is injured, glial cells, of which there are three types — astrocyte, ependymal and NG2 — respond to form glial scar tissue.

“Only NG2 glial cells were found to exhibit neurogenic potential in the spinal cord following injury in adult mice, but they failed to generate mature neurons,” Wu said. “Interestingly, by elevating the critical transcription factor SOX2, the glia-to-neuron conversion is successfully achieved and accompanied with a reduced glial scar formation and increased functional recovery following spinal cord injury.”

The researchers reprogrammed the NG2 cells from the mouse model using elevated levels of SOX2 — a transcription factor found inside the cell that’s essential for neurogenesis — to neurons. This conversion has two purposes, Xu said: generate neurons to replace those lost due to a spinal cord injury and reduce the size of the glial scars in the lesion area of the damaged tissue.

This discovery, Wu said, serves as an important target in the future for potential therapeutic treatments of spinal cord injury.

The partnership between the laboratory of Chun-Li Zhang, PhD, professor at UT Southwestern Medical Center, and Xu’s laboratory at IU School of Medicine greatly benefited the research, Xu added, by offering complementary expertise in neuronal reprogramming and in spinal cord injury, respectively.

“Such a collaboration will be continued between the two laboratories to address neuronal remodeling and functional recovery after successful conversion of glial cells into functional neurons in future,” Xu said.

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Materials provided by Indiana University School of Medicine. Note: Content may be edited for style and length.

The new testing method revealed large quantities of previously undetected PFAS from fire-retardant foams and other unknown sources. Total concentrations of PFAS present in these watersheds were above state maximum contaminant levels (MCLs) for drinking water safety.

“We developed a method to fully capture and characterize all PFAS from fire-retardant foams, which are a major source of PFAS to downstream drinking water and ecosystems, but we also found large amounts of unidentified PFAS that couldn’t have originated from these foams,” said Bridger Ruyle, a graduate student at SEAS and first author of the study. “Traditional testing methods are completely missing these unknown PFAS.”

The research will be published in Environmental Science & Technology.

PFAS — per- and polyfluoroalkyl substances — are present in products ranging from fire retardant foams to non-stick pans. Nicknamed “forever chemicals” due to their long lifespan, PFAS have been building up in the environment since they were first used in the 1950s.

Despite the associated health risks, there are no legally enforceable federal limits for PFAS chemicals in drinking water. The Environmental Protection Agency’s provisional health guidelines for public water supplies only cover PFOS and PFOA, two common types of PFAS. Massachusetts, along with a few other states, has gone further by including six PFAS in their new MCLs in drinking water. But there are thousands of PFAS chemical structures known to exist, several hundred of which have already been detected in the environment.

“We’re simply not testing for most PFAS compounds, so we have no idea what our total exposure is to these chemicals and health data associated with such exposures are still lacking,” said Elsie Sunderland, the Gordon McKay Professor of Environmental Chemistry at SEAS and senior author of the paper.

The standard testing methods used by the EPA and state regulatory agencies only test for 25 or fewer known compounds. The problem is the overwhelming majority of PFAS compounds are proprietary and regulatory agencies can’t find what they don’t know exist.

The new method developed by Sunderland and her team can overcome that barrier and account for all PFAS in a sample. CSI: PFAS

PFAS are made by combining carbons and fluorine atoms to form one of the strongest bonds in organic chemistry. Fluorine is one of the most abundant elements on earth but naturally occurring organic fluorine is exceedingly rare — produced only by a few poisonous plants in the Amazon and Australia. Therefore, any amount of organofluorine detected in the environment is sure to be human made.

PFAS compounds found in the environment come in two forms: a precursor form and a terminal form. Most of the monitored PFAS compounds, including PFOS and PFOA, are terminal compounds, meaning they will not degrade under normal environmental conditions. But precursor compounds, which often make up the majority of PFAS chemicals in a sample, can be transformed through biological or environmental processes into terminal forms. So, while the EPA or state agencies may monitor PFAS concentrations, they still are not detecting much of the huge pool of PFAS precursors.

That’s where this new method comes in.

The researchers first measure all the organofluorine in a sample. Then, using another technique, they oxidize the precursors in that sample and transform them into their terminal forms, which they can then measure. From there, the team developed a method of statistical analysis to reconstruct the original precursors, fingerprint their manufacturing origin, and measure their concentration within the sample.

“We’re essentially doing chemical forensics,” said Sunderland.

Using this method, Sunderland and her team tested six watersheds on Cape Cod as part of a collaboration with the United States Geological Survey and a research center funded by the National Institutes of Health and led by the University of Rhode Island that focuses on the sources, transport, exposure and effects of PFAS.

The team focused on identifying PFAS from the use of fire-retardant foams. These foams, which are used extensively at military bases, civilian airports, and local fire departments, are a major source of PFAS and have contaminated hundreds of public water supplies across the US.

The research team applied their forensic methods to samples collected between August 2017 and July 2019 from the Childs, Quashnet, Mill Creek, Marstons Mills, Mashpee and Santuit watersheds on Cape Cod. During the collection process, the team members had to be careful what they wore, since waterproof gear is treated with PFAS. The team ended up in decades-old waders to prevent contamination.

The sampling sites in the Childs, Quashnet and Mill Creek watersheds are downstream from a source of PFAS from fire retardant foams — the Quashnet and Childs from The Joint Base Cape Cod military facility and Mill Creek from Barnstable County Fire Training Academy.

Current tests can only identify about 50 percent of PFAS from historical foams — products that were discontinued in 2001 due to high levels of PFOS and PFOA — and less than 1 percent of PFAS from modern foams.

Using their new method, Sunderland and her team were able to identify 100 percent of all PFAS compounds in the types of fire-retardant foams that were used for decades at Joint Base Cape Cod and Barnstable County Fire Training Academy.

“Our testing method was able to find these missing compounds that have been used by the chemical industry for more than 40 years,” said Sunderland.

The tests also revealed huge quantities of PFAS from unknown sources.

“Our accounting of PFAS from firefighting foams could not explain 37 to 77 percent of the organofluorine that we measured,” said Ruyle. “This has huge ramifications for not only our understanding of human exposure but also for how much PFAS is discharging into the ocean and accumulating in marine life.”

To follow up on these findings, Ruyle is currently working with NIH to identify some of the health impacts of PFAS from contemporary firefighting foams using toxicology studies. Sunderland’s team is continuing to study the unknown PFAS to better identify their sources and potential for accumulation in abundant marine food webs on Cape Cod.