Researchers at the University of Bonn and the research center caesar have succeeded in ultra-fast freezing proteins after a precisely defined period of time. They were able to follow structural changes on the microsecond time scale and with sub-nanometer precision. Owing to its high spatial and temporal resolution, the method allows tracking rapid structural changes in enzymes and nucleic acids. The results are published in the Journal of the American Chemical Society.
If you want to know what the spatial structure of a biomolecule looks like, you have a formidable arsenal of tools at your disposal. The most popular ones are electron microscopy and X-ray diffraction, which can reveal even the smallest details of a protein. However, a significant limitation of those methods is that they usually deliver static images, which are often insufficient to understand biomolecular processes in precise mechanistic terms. Therefore, a long-term goal of many research groups worldwide has been to track the movements within a macromolecule such as a protein over time while it carries out its work, just like in a movie. The research groups led by Prof. Dr. Olav Schiemann from the Institute of Physical and Theoretical Chemistry at the University of Bonn and Prof. Dr. Benjamin Kaupp from the research center caesar of the Max Planck Society have now come a step closer to achieving this goal.
They chose an ion channel for their investigation. This is a protein that forms miniscule pores in the cell membrane that are permeable to charged particles called ions. “This channel is normally closed,” Schiemann explains. “It only opens when a cellular messenger, called cAMP, binds to it. We wanted to know how exactly this process works.”
Mini magnets to measure distances
To do so, the researchers first mixed the channel protein and cAMP and then rapidly froze the solution. In the frozen state, the protein structure can now be analyzed. For their method to work, they had attached molecular electromagnets at two points in the channel. The distance between these magnets can be determined with a precision of a few Angstrom (ten billionths of a millimeter) using a sophisticated method called PELDOR, which works like a molecular ruler. In recent years, the method was significantly refined and improved in Schiemann’s group.
“However, this only gives us a static image of cAMP binding to the ion channel,” Schiemann says. “We therefore repeated the freezing process at different times after mixing the two molecules. This allowed reconstructing the movements in the protein after cAMP binding — just like a movie, which is also made up of a sequence of images.”
At the center of this procedure is a sophisticated method that allows samples to be mixed and frozen very quickly at a precise point in time. The technique, called “microsecond freeze hyperquenching” (abbreviated MHQ), was originally developed at Delft University, but later fell into disuse. It was rediscovered and decisively refined by Kaupp’s group.
“In the MHQ device, the cAMP molecule and the ion channel are mixed at ultrafast speed,” Kaupp explains. “Then the mixture is shot as a hair-thin stream onto a very cold metal cylinder at -190 °C, which rotates 7,000 times per minute. It was particularly challenging to transfer the frozen samples for the PELDOR measurement from the metal plate into thin glass tubes, and to keep them frozen meanwhile. We had to design and build special tools for that.”
Deep-freezing in 82 millionths of a second
The entire mixing and freezing process takes only 82 microseconds (one microsecond equals a millionth of a second). “This allows us to visualize very rapid changes in the spatial structure of proteins,” explains Tobias Hett, one of the two doctoral students who contributed significantly to the success. The advantage of the method is its combination of high spatial and temporal resolution. “This represents a major step forward in studying dynamic processes in biomolecules,” Kaupp emphasizes.
The researchers now plan to use their method to take a closer look at other biomolecules. They hope to gain new insights, for example into the functioning of enzymes and nucleic acids. The importance of such insights is best illustrated by the recent worldwide surge of structural research on the SARS coronavirus-2: The so-called spike protein of the virus also undergoes a structural change when human cells are infected. Clarifying this mechanism will provide valuable information how to target the infection mechanism with new drugs.
The preparation of the samples, the experimental execution, and the analysis of the data is very complex. The results of the study therefore also reflect a successful scientific cooperation with researchers led by Prof. Dr. Helmut Grubmüller of the Max Planck Institute for Biophysical Chemistry in Göttingen and Prof. Dr. Heinz-Jürgen Steinhoff of the University of Osnabrück.
Story Source:
Materials provided by University of Bonn. Note: Content may be edited for style and length.

The move has been long sought by public health and civil rights groups, after decades of marketing aimed at Black smokers.The Biden administration is planning to propose a ban on menthol cigarettes, a long-sought public health goal of civil rights and anti-tobacco groups that has been beaten back by the tobacco industry for years, according to a federal health official.For decades, menthol cigarettes have been marketed aggressively to Black people in the United States. About 85 percent of Black smokers use menthol brands, including Newport and Kool, according to the Food and Drug Administration. Research shows menthol cigarettes are easier to become addicted to and harder to quit than plain tobacco products.The F.D.A. is being forced to act by a court deadline — a federal district judge in Northern California had ordered the agency to respond by April 29 to a citizens’ petition to ban menthol. But the odds are unlikely that a ban would take effect anytime soon, because any proposal is likely to wind up in a protracted court battle. The proposal would also include a ban on all mass-produced flavored cigars, including cigarillos, which have become popular with teenagers. The ban would not, however, apply to e-cigarettes, which are being considered as a means to help smokers of regular menthol cigarettes quit. Most e-cigarette brands, including Juul, are undergoing an F.D.A. review that will determine whether they are sufficiently beneficial to public health to be allowed to stay on the market. Details of the proposal were first reported by The Washington Post. Delmonte Jefferson, executive director of the Center for Black Health and Equity, one of the organizations behind the petition, called the decision a victory for African Americans and all people of color.“This has been a long time coming,” said Mr. Jefferson. “We’ve been fighting this fight, since back in the 1980s. We told the industry then, we didn’t want those cigarettes in our communities.”Steven Callahan, a spokesman for Altria, which owns Philip Morris, U.S.A. said the company remained opposed to a menthol ban.“We share the common goal of moving adult smokers from cigarettes to potentially less harmful alternatives, but prohibition does not work,” Mr. Callahan said. “A far better approach is to support the establishment of a marketplace of F.D.A.-authorized non-combustible alternatives that are attractive to adult smokers.”Three years ago, the F.D.A., under Dr. Scott Gottlieb, President Trump’s first F.D.A. commissioner, proposed a similar menthol ban. But the Trump administration backed down after intense resistance from tobacco state lawmakers, led by Senator Richard Burr, Republican of North Carolina.Pressure to resurrect a ban had been building since President Biden’s election, and as the coronavirus pandemic and the Black Lives Matter movement further exposed sharp racial disparities in the country’s public health and medical systems.While Black smokers smoke less, they die of heart attacks, strokes and other causes linked to tobacco use at higher rates than white smokers do, according to federal health statistics.Matthew L. Myers, president of Campaign for Tobacco-Free Kids, which was part of the citizens’ petition, also noted that menthol and other flavors appeal widely to teenagers.“Menthol cigarettes are the No. 1 cause of youth smoking in the United States,” he said. “Eliminating menthol cigarettes and flavored cigars used by so many kids will do more in the long run to reduce tobacco-related disease than any action the federal government has ever taken.”Menthol is a substance found in mint plants, and it can also be synthesized in a lab. It creates a cooling sensation in tobacco products and masks the harshness of the smoke, making it more tolerable. Decades ago, marketing research showed it was more appealing to Black smokers than white smokers and cigarette companies began to focus their marketing on Black consumers.Support has also been growing in Congress to enact a ban through legislation. Several states and municipalities, including Massachusetts and California, have instituted their own menthol bans, but many of those are tied up in litigation too.The F.D.A. has not yet announced details of the proposal, which will have to go through a formal federal rule-making process, that can take several years and is likely to face stiff tobacco industry challenges.

Various studies show that people of color are disproportionately exposed to air pollution in the United States. However, it was unclear whether this unequal exposure is due mainly to a few types of emission sources or whether the causes are more systemic. A new study that models peoples’ exposure to air pollution — resolved by race-ethnicity and income level — shows that exposure disparities among people of color and white people are driven by nearly all, rather than only a few, emission source types.
The study led by University of Illinois Urbana Champaign civil and environmental engineering professor Christopher Tessum is published in the journal Science Advances.
“Community organizations have been experiencing and advocating against environmental injustice for decades,” Tessum said. “Our study contributes to an already extensive body of evidence with the new finding that there is no single air pollution source, or a small number of sources, that account for this disparity. Instead, the disparity is caused by almost all of the sources.”
The team used an air quality model to analyze Environmental Protection Agency data for more than 5,000 emission source types, including industry, agriculture, coal electric utilities, light- and heavy-duty gasoline vehicles, diesel vehicles, off-road vehicles and equipment, construction, residential sources, road dust and other miscellaneous small emissions sources. Each source type studied contributes to fine particle air pollution, defined as particles being 2.5 micrometers or less in diameter, the study reports.
To identify patterns of air pollution exposure associated with race-ethnicity and income, the researchers combined the spatial air pollution patterns predicted in their air quality model with residential population counts from the U.S. Census Bureau to identify differences in exposure by race-ethnicity and income.
The researchers found that for the 2014 U.S. total population average, fine particle air pollution exposures from the majority of source types are higher than average for people of color and lower than average for white people. The data indicate that white people are exposed to lower-than-average concentrations from emissions source types that, when combined, cause 60% of their total exposure, the study reports. Conversely, people of color experience greater-than-average exposures from source types that, when combined, cause 75% of their total exposure. This disparity exists at the country, state and city level and for people within all income levels.

Harmful exposures during pregnancy, including some that occur even before pregnancy is recognized, appear to significantly increase a child’s risk for psychiatric or behavioral problems early in life, researchers from Massachusetts General Hospital report.
In their study of 9,290 children from the ages of 9 to 10 living in 21 communities in the United States, the researchers found that children subjected during pregnancy to two or more of six adverse exposures were significantly more likely to have clinically significant scores on the Child Behavior Checklist (CBCL), indicating a higher level of problems such as depression, attention difficulties or anxiety.
The adverse prenatal exposures are unplanned pregnancy; maternal use of alcohol, tobacco or marijuana before pregnancy was recognized; complications during pregnancy (such as high blood pressure or gestational diabetes); and complications during labor and delivery. Pre-term birth or Caesarean delivery were not associated with increased risk.
“While individually these factors had previously been associated with similar risks in prior, often smaller studies, this is the first time that we were able to gauge the effect of cumulative exposures, which were fairly dramatic,” says lead author Joshua L. Roffman, MD, MMSc, director of the Mass General Early Brain Development Initiative.
For example, while children with none of the exposures during their mother’s pregnancy had only a 7% chance of developing clinically significant psychiatric symptoms, this risk increased steeply and in a linear fashion, such that those with four or more of the exposures had a 29% chance of clinically significant symptoms.
As the researchers report in their study, published in the open-access journal PLOS ONE, they saw similar patterns across a range of specific symptoms, from mood and anxiety to attention and thought disturbances.
The associations between prenatal exposures and psychiatric symptoms in childhood held up even when the researchers accounted for other factors that might skew the results, such as the mother’s socioeconomic status, or exposures after birth that are known to increase a child’s risk for psychiatric disorders, such as a traumatic life event.
To validate their findings, Roffman and colleagues also tested them in a separate group of non-twin siblings who differed in their exposures during pregnancy, and here too the data showed that the sibling with the higher number of exposures was at greater risk for more severe symptoms.
A limitation of the results is that they are based on the mother’s recall of events during pregnancy, although the frequency of adverse events closely followed national trends. The study did not measure the effects of maternal infections or stress during pregnancy, although each of these has also been associated with increased risk in previous studies.
Given the additive effects of the common exposures they studied, Roffman and colleagues speculate that the “floor” of risk for psychiatric symptoms may have been raised for children born during the COVID-19 pandemic.
“Our findings reinforce the importance of the prenatal environment for brain health and for reducing risk of psychiatric symptoms in childhood. This brings increased urgency to the need to discover, develop and implement early life interventions that mitigate some of these risks,” says Roffman, who is also an associate professor of Psychiatry at Harvard Medical School (HMS).
Improving child brain development and psychiatric health is the main goal of the Mass General Early Brain Development Initiative, a multidisciplinary collaboration among staff in the Departments of Psychiatry, Obstetrics, Pediatrics and Medicine.

Scientists are developing a completely new ‘brain stress test’ for evaluating the mental status of patients with Parkinson’s disease, the second most prevalent neurodegenerative disease worldwide. It involves awakening the ‘ghosts’ hidden in specific networks of the brain to predict the onset of hallucinations.
“We’re developing something similar to a cardiac stress test, but instead of testing the heart, we’re testing the brain,” says EPFL neuroscientist Olaf Blanke.
EPFL scientists are providing a new way to evaluate the onset of hallucinations in patients with Parkinson’s disease with the help of a newly developed brain stress test, focusing their research on presence hallucinations. They also provide evidence of a promising biomarker for predicting the severity of the disease’s progression. The results of their three-tier study, involving 56 patients affected by the disease and recruited at several centers in Switzerland and Spain, are published in today’s edition of Science Translational Medicine (STM).
“An important challenge with hallucinations is that they occur spontaneously, that their occurrence cannot be predicted, that many patients may not openly report them, possibly out of fear, and that it is currently very challenging for physicians to quantify their occurrence, phenomenology and intensity,” continues Fosco Bernasconi, co-first author of the paper. “We have established a robotic-medical device and procedure that can provoke a specific hallucination, the presence hallucination, safely and under controlled conditions in a hospital setting.”
A spectrum of hallucinations in Parkinson’s
Parkinson’s disease is well-known for leading to slowness of movement, muscle stiffness, as well as uncontrollable shaking of the limbs. But alterations of movement are far from being the only symptom of the disease.

The Pfizer-BioNTech and Moderna coronavirus vaccines are 94 percent effective at preventing hospitalization in fully vaccinated adults 65 or older, according to a small study released by the Centers for Disease Control and Prevention on Wednesday.The findings, which are consistent with the clinical trial results, are the first real-world evidence from the United States that the vaccines protect against severe Covid-19. Older adults are at the highest risk of hospitalization and death from the disease. More than 573,000 people have died across the country related to the virus, according to a New York Times database, and as of Tuesday, 141.8 million people have received at least one dose of one of three federally authorized vaccines, including about 96.7 million people who have been fully vaccinated.“These findings are encouraging and welcome news for the two-thirds of people aged 65 and up who are already fully vaccinated,” Dr. Rochelle Walensky, the C.D.C. director, said in a statement. “Covid-19 vaccines are highly effective and these real-world findings confirm the benefits seen in clinical trials, preventing hospitalizations among those most vulnerable.”The study is based on data from 417 patients who were admitted to 24 hospitals in 14 states between January 1 and March 26. Approximately half were 75 or older.Both the Pfizer and Moderna vaccines require two shots, spaced three to four weeks apart. Older adults who were partially vaccinated — that is, they had received one dose of the vaccine more than two weeks prior — were 64 percent less likely to be hospitalized with the coronavirus than unvaccinated seniors, the researchers reported.The vaccines did not reduce hospitalization rates in people who had received their first dose less than two weeks prior. The body requires time to mount an effective immune response, and people are considered fully vaccinated two weeks after the last dose in the series.“This also highlights the continued risk for severe illness shortly after vaccination, before a protective immune response has been achieved and reinforces the need for vaccinated adults to continue physical distancing and prevention behaviors,” the scientists wrote.

A higher ratio of green spaces at the county level is associated with a lower racial disparity in coronavirus infection rates, according to a new study. It is the first study to report the significant relationship between the supply of green spaces and reduced disparity in infectious disease rates.
The research team included William Sullivan, a landscape architecture professor at the University of Illinois Urbana-Champaign, and was led by Bin Jiang, a landscape architecture professor at The University of Hong Kong who received his Ph.D. at Illinois, and Yi Lu, an architecture professor at City University of Hong Kong. They reported their findings in the journal Environment International.
Previous studies by Sullivan, Jiang and Lu have shown that green spaces have positive effects on health. Access to green spaces is associated with improved cognitive performance, reduced mental fatigue and stress, reduced impulsiveness and aggressiveness, increased sense of safety, reduced crime rate, increased physical activity and increased social cohesion.
Prior studies also provide strong evidence that green spaces may mitigate racial disparities in health outcomes. However, none have looked at the effect on disparities in infectious diseases. Most studies examining the racial disparity in coronavirus infections have focused on its association with socio-economic status or pre-existing chronic disease factors.
For this study, the researchers identified 135 of the most urbanized counties in the U.S., with a total population of 132,350,027, representing 40.3% of the U.S. population. They collected infection data from county health departments from late January to July 10, 2020, and used it to calculate the infection rates for Black and white residents of the counties, while controlling for differences in income, pre-existing chronic diseases and urban density.
The data showed that the average infection rate for Black residents was more than twice that of white residents — 497 per 100,000 people for white individuals versus 988 per 100,000 people for Black individuals.

As of April 2021, about 2.8 million people worldwide have died of COVID-19. Early in the pandemic, researchers developed accurate diagnostic tests and identified health conditions that correlated with worse outcomes. However, a clinical predictor of who faces the highest risk of being hospitalized, put on a ventilator or dying from the disease has remained largely out of reach.
This week in mSphere, an open-access journal of the American Society for Microbiology, researchers describe a two-step prognostic test that can help predict a patient’s response to infection with SARS-CoV-2. The test combines a disease risk factor score with a test for antibodies produced early in the infection. It could be administered at the time of diagnosis to help guide therapeutic choices before the most severe symptoms appear, the researchers said.
“You can predict with really high sensitivity that someone is going to have a severe case of COVID-19,” said Emily Sanders, a graduate student in the lab of chemical biologist Gregory Weiss, Ph.D, at the University of California, Irvine. Sanders led the study together with Sanjana Sen and Kristin Gabriel, also graduate students in Weiss’s lab.
Most diagnostic tests search for antibodies associated with interrupting the virus. Weiss said the group initially set out to develop their own diagnostic, following this same strategy, but quickly realized that plenty of competing tests would soon be available. Instead, they pivoted to focus on other, unstudied antibodies — ones that wouldn’t necessarily disrupt the virus or help the immune system fight the infection.
“Everyone else was looking for the good antibodies that neutralize the virus,” said Weiss, senior author on the study. “We weren’t seeing enough about antibodies that are unhelpful.”
“Being able to identify a ‘bad’ antibody response helps to fill in a research gap,” said Gabriel.
Previous studies have predicted that the SARS-CoV-2 particle has more than 55 epitopes, or sites on the virus where antibodies can attach. The best studied epitopes to date are those found on the S, or spike, protein, but the virus has three other structural proteins, each with epitopes worth investigating, said Sen. Using ELISAs, or enzyme-linked immunosorbent assays, the researchers compiled a list of antibodies that might correlate with worse prognosis and ultimately focused on one that attaches to epitope 9 on the N, or nucleocapsid, protein. The group also developed a tool that used data on factors including age, sex, and pre-existing health conditions to produce a disease risk factor score (DRFS).
They tested their tool on a group of 86 people who had tested positive for the coronavirus. Patients whose tests revealed the presence of epitope 9 antibodies were more likely to have prolonged illness and worse outcomes than people without the antibodies. Of the 23 people in the study who did have the antibodies associated with epitope 9, a high DRFS predicted disease severity with more than 92% sensitivity.
The test uses technology and tools readily available in testing labs, Weiss said. “Detecting antibodies is super easy to do,” he said, and an inexpensive prognostic test could inform treatment decisions early in the disease progression. The researchers found that the epitope-9 antibodies become detectable between 1 and 6 days after the onset of symptoms.
“We’ve all had friends and family impacted by this disease,” said Weiss, “and we wanted to do something that might be useful, that might help the physicians who are being overwhelmed.”
Story Source:
Materials provided by American Society for Microbiology. Note: Content may be edited for style and length.

Tiny molecules called nanobodies, which can be designed to mimic antibody structures and functions, may be the key to blocking a tick-borne bacterial infection that remains out of reach of almost all antibiotics, new research suggests.
The infection is called human monocytic ehrlichiosis, and is one of the most prevalent and potentially life-threatening tick-borne diseases in the United States. The disease initially causes flu-like symptoms common to many illnesses, and in rare cases can be fatal if left untreated.
Most antibiotics can’t build up in high enough concentrations to kill the infection-causing bacteria, Ehrlichia chaffeensis, because the microbes live in and multiply inside human immune cells. Commonly known bacterial pathogens like Streptococcus and E. coli do their infectious damage outside of hosts’ cells.
Ohio State University researchers created nanobodies intended to target a protein that makes E. chaffeensis bacteria particularly infectious. A series of experiments in cell cultures and mice showed that one specific nanobody they created in the lab could inhibit infection by blocking three ways the protein enables the bacteria to hijack immune cells.
“If multiple mechanisms are blocked, that’s better than just stopping one function, and it gives us more confidence that these nanobodies will really work,” said study lead author Yasuko Rikihisa, professor of veterinary biosciences at Ohio State.
The study provided support for the feasibility of nanobody-based ehrlichiosis treatment, but much more research is needed before a treatment would be available for humans. There is a certain urgency to coming up with an alternative to the antibiotic doxycycline, the only treatment available. The broad-spectrum antibiotic is unsafe for pregnant women and children, and it can cause severe side effects.

Analysis of data from a lightning mapper and a small, hand-held radiation detector has unexpectedly shed light on what a gamma-ray burst from lightning might look like — by observing neutrons generated from soil by very large cosmic-ray showers. The work took place at the High Altitude Water Cherenkov (HAWC) Cosmic Ray Observatory in Mexico.
“This was an accidental discovery,” said Greg Bowers, a scientist at Los Alamos National Laboratory and lead author of the study published in Geophysical Research Letters. “We set up this system to study terrestrial gamma-ray flashes — or gamma-ray bursts from lightning — that are typically so bright you can see them from space. The idea was that HAWC would be sensitive to the gamma-ray bursts, so we installed a lightning mapper to capture the anatomy of the lightning development and pinpoint the lightning processes producing them.”
The team, including Xuan-Min Shao and Brenda Dingus also from Los Alamos, used a small, handheld particle detector, expecting that a terrestrial gamma-ray flash would generate a clear gamma-ray signal in the small particle detector.
“Our system ran for almost two years, and we saw a lot of lightning,” said Bowers. But during those storms, they did not observe anything that looked like terrestrial gamma-ray flashes. “We did, however, see large count-rate bursts during clear, fair-weather days, which made us scratch our heads.”
HAWC data gathered during these times showed that, in every case, the large array that comprises HAWC had been overwhelmed by extremely large cosmic-ray showers — so large that the Los Alamos researchers couldn’t estimate their size.
UC Santa Cruz collaborator David Smith found that these fair-weather bursts had previously been observed by scientists in Russia, who called them “neutron bursts,” and determined that they were the result of neutron production in the soil around the impact point of cosmic ray shower cores.
Previous work that simulated these events had only considered hadrons — a type of subatomic particle — in the core of the showers. In addition to hadrons and other particles, cosmic-ray shower cores also contain a lot of gamma rays.
For this work, William Blaine, also of Los Alamos, simulated large cosmic ray-showers, and included both hadrons and gamma rays. “We were able to match our observations with the simulations,” said Bowers. “We found that the gamma rays produce the same type of neutron burst as the hadrons.”
This study suggests that any natural phenomena that produces a beam of gamma-rays pointed towards the ground (such as downward terrestrial gamma-ray flashes), could produce a similar “neutron burst” signature. This is significant for future terrestrial gamma-ray flash observation modeling efforts.
“It tell us that you can’t just model the gamma rays hitting your detector, you’ll also have to consider the neutron burst that’s happening nearby,” said Bowers.
The HAWC Observatory comprises an array of water-filled tanks high on the flanks of the Sierra Negra volcano in Puebla, Mexico, where the thin atmosphere offers better conditions for observing gamma rays. When gamma rays strike molecules in the atmosphere they produce showers of energetic particles. When some of those particles strike the water inside the HAWC detector tanks, they produce flashes of light called Cherenkov radiation. By studying these Cherenkov flashes, researchers reconstruct the sources of the showers to learn about the particles that caused them.
Story Source:
Materials provided by DOE/Los Alamos National Laboratory. Note: Content may be edited for style and length.