The spacecraft captured images of the sample collector head as it moved through several different positions. In reviewing these images, the OSIRIS-REx team noticed both that the head appeared to be full of asteroid particles, and that some of these particles appeared to be escaping slowly from the sample collector, called the Touch-And-Go Sample Acquisition Mechanism (TAGSAM) head. They suspect bits of material are passing through small gaps where a mylar flap — the collector’s “lid” — is slightly wedged open by larger rocks.

“Bennu continues to surprise us with great science and also throwing a few curveballs,” said Thomas Zurbuchen, NASA’s associate administrator for science at the agency’s headquarters in Washington. “And although we may have to move more quickly to stow the sample, it’s not a bad problem to have. We are so excited to see what appears to be an abundant sample that will inspire science for decades beyond this historic moment.”

The team believes it has collected a sufficient sample and is on a path to stow the sample as quickly as possible. They came to this conclusion after comparing images of the empty collector head with Oct. 22 images of the TAGSAM head after the sample collection event.

The images also show that any movement to the spacecraft and the TAGSAM instrument may lead to further sample loss. To preserve the remaining material, the mission team decided to forego the Sample Mass Measurement activity originally scheduled for Saturday, Oct. 24, and canceled a braking burn scheduled for Friday to minimize any acceleration to the spacecraft.

From here, the OSIRIS-Rex team will focus on stowing the sample in the Sample Return Capsule (SRC), where any loose material will be kept safe during the spacecraft’s journey back to Earth.

“We are working to keep up with our own success here, and my job is to safely return as large a sample of Bennu as possible,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona in Tucson, who leads the science team and the mission’s science observation planning and data processing. “The loss of mass is of concern to me, so I’m strongly encouraging the team to stow this precious sample as quickly as possible.”

The TAGSAM head performed the sampling event in optimal conditions. Newly available analyses show that the collector head was flush with Bennu’s surface when it made contact and when the nitrogen gas bottle was fired to stir surface material. It also penetrated several centimeters into the asteroid’s surface material. All data so far suggest that the collector head is holding much more than 2 ounces of regolith.

OSIRIS-REx remains in good health, and the mission team is finalizing a timeline for sample storage. An update will be provided once a decision is made on the sample storage timing and procedures.

NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering and the safety and mission assurance for OSIRIS-REx. Lockheed Martin Space in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace of Tempe, Arizona, are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

For more information, see: https://www.nasa.gov/osiris-rex

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An international team of scientists led by Dominique Segura-Cox at the Max Planck Institute for Extraterrestrial Physics (MPE) in Germany targeted the proto-star IRS 63 with the ALMA radio observatory. This system is 470 light years from Earth and located deep within the dense L1709 interstellar cloud in the Ophiuchus constellation. Proto-stars as young as IRS 63 are still swaddled in a large and massive blanket of gas and dust called an envelope, and the proto-star and disk feed from this reservoir of material.

In systems older than 1,000,000 years, after the proto-stars have finished gathering most of their mass, rings of dust have been previously detected in great numbers. IRS 63 is different: at under 500,000 years old, it is less than half the age of other young stars with dust rings and the proto-star will still grow significantly in mass. “The rings in the disk around IRS 63 are so young,” emphasizes Segura-Cox. “We used to think that stars entered adulthood first and then were the mothers of planets that came later. But now we see that proto-stars and planets grow and evolve together from early times, like siblings.”

Planets face some serious obstacles during their earliest stages of formation. They have to grow from tiny dust particles, smaller than household dust here on Earth. “The rings in the disk of IRS 63 are vast pile-ups of dust, ready to combine into planets,” notes co-author Anika Schmiedeke at MPE. However, even after the dust clumps together to form a planet embryo, the still-forming planet could disappear by spiraling inwards and being consumed by the central proto-star. If planets do start to form very early and at large distances from the proto-star, they may better survive this process.

The team of researchers found that there is about 0.5 Jupiter masses of dust in the young disk of IRS 63 further than 20 au from its center (at a distance similar to the Uranus orbit in our solar system). That is not counting the amount of gas, which could add up to 100 times more material. It takes at least 0.03 Jupiter masses of solid material to form a planet core that will efficiently accrete gas and grow to form a giant gas planet. Team member Jaime Pineda at MPE adds, “These results show that we must focus on the youngest systems to truly understand planet formation.” For example, there is growing evidence that Jupiter may have actually formed much farther out in the Solar System, beyond the Neptune orbit, and then migrated inwards to its present location. Similarly, the dust surrounding IRS 63 shows that there is enough material far from the proto-star and at a stage young enough that there is a chance for this Solar System analogue to form planets in the way that Jupiter is suspected to have formed.

“The size of the disk is very similar to our own Solar System,” Segura-Cox explains. “Even the mass of the proto-star is just a little less than our Sun’s. Studying such young planet-forming disks around proto-stars can give us important insights into our own origins.”

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Mapping these shields will give researchers a more complete understanding of why antibodies react to some spots on the virus but not others, and may shape the design of new vaccines that target the most vulnerable and accessible sites on HIV and other viruses.

The sugar molecules, or “glycans,” are loose and stringy, and function as shields because they are difficult for antibodies to grip and block access to the protein surface. The shields form on the outermost spike proteins of HIV and many other viruses, including SARS-CoV-2, the coronavirus that causes COVID-19, because these viruses have evolved sites on their spike proteins where glycan molecules — normally abundant in cells — will automatically attach.

“We now have a way to capture the full structures of these constantly fluctuating glycan shields, which to a great extent determine where antibodies can and can’t bind to a virus such as HIV,” says the study’s lead author Zachary Berndsen, PhD, a postdoctoral research associate in the structural biology lab of Scripps Research Professor Andrew Ward, PhD.

The same wavy flexibility that makes these sugary molecules resistant to antibodies has made them impossible for researchers to capture with traditional atomic-scale imaging. In the new study, which appears in the Proceedings of the National Academy of Sciences, the scientists developed techniques that, for the first time, allow these elusive molecules to be mapped in great detail on the surface of the HIV spike protein, known as “Env.”

The Scripps Research team collaborated with the lab of Gnana Gnanakaran, PhD, staff scientist at Los Alamos National Laboratory, which is equipped with high-performance computing resources that enabled fresh approaches for modeling the glycans.

The researchers combined an atomic-scale imaging method called cryo-electron microscopy (cryo-EM) with sophisticated computer modeling and a molecule-identifying technique called site-specific mass spectrometry. Cryo-EM relies on averaging tens or hundreds of thousands of individual snapshots to create a clear image, thus highly flexible molecules like glycans will appear only as a blur, if they show up at all.

But by integrating cryo-EM with the other technologies, the researchers were able to recover this lost glycan signal and use it to map sites of vulnerability on the surface of Env.

“This is the first time that cryo-EM has been used along with computational modeling to describe the viral shield structure in atomic detail,” says Srirupa Chakraborty, PhD, co-lead author and post-doctoral researcher in the Gnanakaran lab at Los Alamos National Laboratory.

The new combined approach revealed the glycans’ structure and dynamic nature in extreme detail and helped the team better understand how these complex dynamics affect the features observed in the cryo-EM maps. From this wealth of information, the team observed that individual glycans do not just wiggle around randomly on the spike protein’s surface, as once was thought, but instead clump together in tufts and thickets.

“There are chunks of glycans that seem to move and interact together,” Berndsen says. “In between these glycan microdomains is where antibodies apparently have the opportunity to bind.”

Experimental HIV vaccines rely on modified, lab-made Env proteins to elicit antibody responses. In principle, these vaccines’ effectiveness depends in part on the positioning and extent of the shielding glycans on these lab-made viral proteins. Therefore, Berndsen and colleagues applied their method to map the glycans on a modified HIV Env protein, BG505 SOSIP.664, which is used in an HIV vaccine currently being evaluated in clinical trials.

“We found spots on the surface of this protein that normally would be covered with glycans but weren’t — and that may explain why antibody responses to that site have been noted in vaccination trials,” Berndsen says.

That finding, and others in the study, showed that Env’s glycan shield can vary depending on what type of cell is being used to produce it. In HIV’s infections of humans, the virus uses human immune cells as factories to replicate its proteins. But viral proteins used to make vaccines normally are produced in other types of mammalian cells.

In another surprise discovery, the team observed that when they used enzymes to slowly remove glycans from HIV Env, the entire protein began to fall apart. Berndsen and colleagues suspect that Env’s glycan shield, which has been considered merely a defense against antibodies, may also have a role in managing Env’s shape and stability, keeping it poised for infection.

The team expect that their new glycan-mapping methods will be particularly useful in the design and development of vaccines — and not only for HIV. Many of the techniques can be applied directly to other glycan-shielded viruses such as influenza viruses and coronaviruses, and can be extended to certain cancers in which glycans play a key role, the researchers say.

In studies with rodents, researchers found that males and females exhibit their own distinct symptoms and brain features of PTSD and alcohol use disorder. Such differences are not typically accounted for in laboratory-based studies yet could lead to more successful clinical treatments.

The findings, published in Molecular Psychiatry, also present a new model for identifying biomarkers that may indicate a person with PTSD is more likely to develop alcohol use disorder.

“Having PTSD significantly increases the risk of developing alcohol use disorder, as individuals use alcohol to cope with stress and anxiety. Yet the underlying biology of comorbid disorders is generally not well understood,” says Dean Kirson, PhD, a postdoctoral fellow in neurophysiology in the lab of professor Marisa Roberto, PhD, and a co-lead author with Michael Steinman, PhD. “We hope our new knowledge of sex-specific changes in the brain will help propel the development of more targeted treatments.”

About 7 percent to 8 percent of the country’s population will have PTSD at some point in their life, according to the U.S. Department of Veterans Affairs. Causes include combat exposure, physical abuse, an accident or other forms of trauma. Alcohol abuse disorder is also common, affecting some 15 million people in the United States. Those with stress and anxiety disorders such as PTSD are not only more likely to abuse alcohol, but also have increased alcohol withdrawal symptoms and relapse risk.

“Most people know or will know someone struggling with one or both of these disorders and may try to help them. However, there are very few effective treatments currently,” Roberto says. “Both are complex disorders that affect similar brain circuitry. My lab has been studying addiction and stress separately, so here we teamed up with the Zorrilla lab to apply a novel translationally-relevant behavioral model to examine what changes occur when these disorders are comorbid.”

The joint study between Roberto and Eric Zorrilla, PhD — who are co-senior authors — examined behavior, sleep patterns, inflammatory immune responses and levels of a neurotransmitter known as GABA (short for gamma-Aminobutyric acid), which lowers anxiety and increases feelings of relaxation and is a common feature of alcohol dependence.

For both male and female rats, traumatic stress and alcohol exacerbated other behaviors common in PTSD, such as social avoidance startle reactions and defensive behavior. Those who were identified as “drinking-vulnerable” prior to trauma most strongly showed avoidance of trauma-reminiscent places.

However, the scientists noted key differences in how males and females behave following trauma and saw markedly different patterns of GABA signaling. For example, males showed increased GABA receptor function, while females showed increased GABA release.

“This may be important because there is growing awareness that medicines could potentially have different levels of effectiveness in male and female patients and understanding the biology that explains why these differences exist could improve outcomes,” Steinman says.

The team also found that males exhibited an immune-based biomarker — small proteins known as cytokines, which are secreted by immune cells — that determined vulnerability to alcohol use disorder. The females did not.

“We identified profiles of specific cytokines, many not previously linked to stress behaviors, that strongly related to poor drinking outcomes,” says Zorilla, associate professor

In the Department of Molecular Medicine. “These may be important clinically or even mechanistically, but they were unique to males, so we have work ahead of us to find similar biomarkers for females.”

The Roberto and Zorrilla labs plan to conduct additional research into the mechanisms behind the biological changes they observed and test which brain systems can be targeted to treat both PTSD and alcohol abuse.

“We also plan to further investigate the role of the immune system in these disorders,” Roberto says. “These distinct biomarkers may aid in targeted treatment.”

Such molecules are often found in plants and other organisms, and many are considered desirable starting points for developing potential new drugs. But they also tend to be highly challenging for chemists to construct and modify in the lab — a process called synthesis.

The team used computer modeling and a theoretical framework centered on the concept of “information density” to illuminate chemistry principles underlying their landmark 2019 synthesis of the molecule bilobalide, which is produced in the leaves of the ginkgo tree, Ginkgo biloba. Bilobalide is a particularly complex and compact molecule that has shown promise as a potential neurological or psychiatric drug.

The scientists believe that the theoretical fruits of their new study, published in the Journal of the American Chemical Society, will enable chemists to devise more efficient syntheses of such challenging natural molecules — potentially opening up a new realm of powerfully bioactive compounds for development into medicines and other products.

“When we initially achieved our synthesis of bilobalide, we were essentially following our intuition, but in this new study we dug down to understand how the chemistry actually works and developed principles that we think can be applied to other challenges in organic synthesis,” says Ryan Shenvi, PhD, a professor of chemistry at Scripps Research and the senior author of the study.

Creating a valuable natural compound

Bilobalide — which evolved in the ginkgo tree, likely to protect its leaves from insects — blocks an insect nerve-cell receptor called RDL. The fact that the molecule kills insects yet seems quite safe in mammals and dissipates quickly in the environment has attracted interest for safe crop protection.

Bilobalide holds strong promise for medicinal use, with evidence that it’s relatively safe for humans. It blocks human brain-cell receptors called GABAA receptors, which are evolutionary cousins of insect RDL receptors. An intriguing 2007 study found that the compound could reverse cognitive and memory deficits in mice with a neurological condition modeling human Down syndrome, while other studies have suggested it may protect brain cells from certain kinds of harm.

Although natural bilobalide is synthesized by specialized enzymes in the ginkgo tree’s cells, chemists would like to be able to make it in the lab with organic chemistry techniques. In this way, they could obtain large quantities of the compound and modify it to explore and optimize its properties.

But the synthesis of bilobalide has always been a major challenge for scientists, because the molecule packs a relatively complex set of atoms — including eight reactive oxygens — into an odd and highly compact chemical structure. If they could overcome that challenge, chemists would have a way to make molecules of potentially enormous value.

“When you have complexity that is condensed to that extent, you start to see interesting emergent properties,” Shenvi says.

‘Information density’ brings deep understanding

In the study, Shenvi and his colleagues evaluated their 11-step synthesis of bilobalide, achieved in 2019, as well as two longer bilobalide syntheses that had been published previously.

With the help of computational modeling from collaborator Kendall Houk, PhD, the Saul Winstein Distinguished Research Chair in Organic Chemistry at UCLA, and a formal theory of “molecular information content” published in 2016 by German researcher Thomas Böttcher, they developed a concept of “information density” — essentially, complexity divided by molecular volume — and used that to analyze the bilobalide syntheses.

Their analysis showed that bilobalide, even compared with other naturally derived, compact and biologically active molecules, has a very high information density, and that its information content comes principally from its oxygen atoms and asymmetric carbon backbone.

The work revealed that the Shenvi lab’s synthesis of bilobalide was efficient due to fragment coupling — merging already-complex oxygen-containing molecules — and then making careful modifications to overcome the unusual emergent properties of the system.

The chemistry principles the team developed make sense of their bilobalide synthesis and its greater efficiency over prior syntheses, but are also applicable to many other unsolved problems involving natural-molecule synthesis, the researchers say.

As part of the work, co-author Stefano Forli, PhD, wrote a computer script in the Python coding language to automate the calculation of molecular information, which can be otherwise laborious, at the rate of more than 100,000 molecules per minute. (The script is available for download.) Forli is assistant professor in Scripps Research’s Department of Integrative Structural and Computational Biology.

Collaborating investigator Marisa Roberto, PhD, professor in the Department of Molecular Medicine at Scripps Research, studied the activity of bilobalide and another information-dense molecule, jiadifenolide, which Shenvi’s team also recently synthesized. In rodent studies, she found that both bilobalide and jiadifenolide showed promise as relatively potent and safe GABAA blockers, suggesting the potential for being translated into drugs for psychiatric conditions involving abnormal GABAA activity.

“The GABA system is dramatically altered in neuropsychiatric disorders such as alcoholism and other forms of addiction, for which one or both of these compounds might one day prove useful,” Roberto says.

A new study led by researchers at the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science looked at the immune system of elkhorn coral (Acropora palmata), an important reef-building coral in the Caribbean, to better understand its response to diseases such as white band disease and rapid tissue loss.

In the experiment, healthy corals were grafted to diseased ones. After one week, the corals were analyzed to study the coral’s overall gene expression in response to disease, if they exhibited an immune response, and whether there were different signatures of gene expression for corals that didn’t show signs of disease transmission. The researchers found that A. palmata has a core immune response to disease regardless of the type of disease, indicating that this particular coral species mounts an immune response to disease exposure despite differences in the disease type and virulence.

“Our results show that elkhorn coral is not immunocompromised but instead is actually actively trying to fight off disease,” said Nikki Traylor-Knowles, an assistant professor of marine biology and ecology at the UM Rosenstiel School and senior author of the study. “This gives me hope that the corals are fighting back with their immune system.”

Based upon these findings, the researchers suggest that corals that did not get disease may have tougher epithelia, a protective layer of cells covering external surfaces of their body. And, that the symbiotic dinoflagellate, Symbiodiniaceae, that live inside corals did not have differences in gene expression in response to disease, but over the course of the two-year study did develop differences.

Coral disease is considered one of the major causes of coral mortality and disease outbreaks are expected to increase in frequency and severity due to climate change and other human-made stressors. The Caribbean branching coral Acropora palmata which has already seen an 80 percent decrease on reefs primarily due to disease, which has resulted in them being classified as threatened under the US Endangered Species Act.

“These corals are keystone species for Florida reefs, so understanding that their immune systems are active is an important component that can be useful for protecting reefs,” said Traylor-Knowles.

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Materials provided by University of Miami Rosenstiel School of Marine & Atmospheric Science. Original written by Diana Udel. Note: Content may be edited for style and length.