The research was done on Dungeness crabs and found that ocean acidification causes them to physically sniff less, impacts their ability to detect food odours and even decreases activity in the sensory nerves responsible for smell.

“This is the first study to look at the physiological effects of ocean acidification on the sense of smell in crabs,” says Cosima Porteus, an assistant professor in the department of biological sciences at U of T Scarborough and co-author of the study along with postdoc Andrea Durant.

Ocean acidification is the result of the Earth’s oceans becoming more acidic due to absorbing increasing amounts of carbon dioxide in the atmosphere. It’s a direct consequence of burning fossil fuels and carbon pollution, and several studies have shown it’s having an impact on the behaviour of marine wildlife.

Dungeness crabs are an economically important species found along the Pacific coast, stretching from California to Alaska. They are one of the most popular crabs to eat and their fishery was valued at more than $250 million in 2019.

Like most crabs, they have poor vision, so their sense of smell is crucial in finding food, mates, suitable habitats and avoiding predators, explains Porteus. They sniff through a process known as flicking, where they flick their antennules (small antenna) through the water to detect odours. Tiny neurons responsible for smell are located inside these antennules, which send electrical signals to the brain.

The researchers discovered two things when the crabs were exposed to ocean acidification: they were flicking less and their sensory neurons were 50 per cent less responsive to odours.

“Crabs increase their flicking rate when they detect an odour they are interested in, but in crabs that were exposed to ocean acidification, the odour had to be 10 times more concentrated before we saw an increase in flicking,” says Porteus.

There are a few potential reasons why ocean acidification seems to be impacting sense of smell in crabs. Porteus points to other research done at the University of Hull that showed ocean acidification disrupts odour molecules, which can impact how they bind to smell receptors in marine animals such as crabs.

For this study, published in the journal Global Change Biology, Porteus and Durant were able to test the electrical activity in the crabs’ sensory neurons to determine they were less responsive to odours. They also discovered that they had fewer receptors and their sensory neurons were physically shrinking by as much as 25 per cent in volume.

“These are active cells and if they aren’t detecting odours as much, they might be shrinking to conserve energy. It’s like a muscle that will shrink if you don’t use it,” she says.

Porteus says reduced food detection could have implications for other economically important species such as Alaskan king and snow crabs because their sense of smell functions the same way.

“Losing their sense of smell seems to be climate related, so this might partially explain some of the decline in their numbers,” says Porteus.

“If crabs are having trouble finding food, it stands to reason females won’t have as much energy to produce eggs.”

This research was supported by the Natural Sciences and Engineering Research Council of Canada. Some of the analysis was performed at U of T’s Centre for the Neurobiology of Stress.

The research represents a nearly-unprecedented feat of data analysis: From 2020 to 2022, the small army of mostly first- and second-year students examined the physics of more than 600 real solar flares — gigantic eruptions of energy from the sun’s roiling corona.

The researchers, including 995 undergraduate and graduate students, published their finding May 9 in The Astrophysical Journal. The results suggest that solar flares may not be responsible for superheating the sun’s corona, as a popular theory in astrophysics suggests.

“We really wanted to emphasize to these students that they were doing actual scientific research,” said James Mason, lead author of the study and an astrophysicist at the Johns Hopkins University Applied Physics Laboratory.

Study co-author Heather Lewandowski agreed, noting that the study wouldn’t be possible without the undergrads who contributed an estimated 56,000 hours of work to the project.

“It was a massive effort from everyone involved,” said Lewandowski, professor of physics and fellow of JILA, a joint research institute between CU Boulder and the National Institute of Standards and Technology (NIST).

Campfire physics

The study zeroes in on a mystery that has left even senior astrophysicists scratching their heads.

Telescope observations suggest that the sun’s corona sizzles at temperatures of millions of degrees Fahrenheit. The surface of the sun, in contrast, is much cooler, registering only in the thousands of degrees.

“That’s like standing right in front of a campfire, and as you back away, it gets a lot hotter,” Mason said. “It makes no sense.”

Some scientists suspect that especially tiny flares, or “nanoflares,” which are too small for even the most advanced telescopes to spot, may be responsible. If such events exist, they may pop up across the sun on a nearly constant basis. And, the theory goes, they could add up to make the corona toasty. Think of boiling a pot of water using thousands of individual matches.

The students’ results cast doubt on this theory, Mason said, although he thinks it’s too early to say for sure.

“I was hoping our result was going to be different. I still feel like nanoflares are an important driver of coronal heating,” Mason said. “But the evidence from our paper suggests the opposite. I’m a scientist. I have to go where the evidence is pointing.”

Peak pandemic times

The effort began at the height of the COVID-19 pandemic.

In spring 2020, CU Boulder, like most universities around the country, had moved its courses entirely online. Lewandowski, however, faced a predicament: She was teaching a class on hands-on research called “Experimental Physics I” that fall, and she had nothing for her students to do.

“This was peak pandemic times,” Lewandowski said. “It’s sometimes hard to remember back to what life was like then. These students were very isolated. They were really stressed.”

Mason, who was then a researcher at the Laboratory for Atmospheric and Space Physics (LASP) at CU Boulder, offered an idea.

The scientist had long wanted to dig into the mathematics of solar flares. In particular, he had tried examining a dataset of thousands of flares that occurred between 2011 and 2018 and had been spotted by instruments in space. They included the National Oceanic and Atmospheric Administration’s Geostationary Operational Environmental Satellite (GOES) series and NASA’s Miniature X-ray Solar Spectrometer (MinXSS), a CubeSat mission designed and built at LASP.

The problem: There were just too many flares to examine on his own.

That’s when Mason and Lewandowski turned to the students for help.

Mason explained that you can infer details about the behavior of nanoflares by studying the physics of larger flares, which scientists have observed directly for decades.

To do just that, students split into groups of three or four and picked a normal flare they wanted to analyze over the course of the semester. Then, through a series of lengthy calculations, they added up how much heat could each of these events pour into the sun’s corona.

Their calculations painted a clear picture: The sum of the sun’s nanoflares likely wouldn’t be powerful enough to heat up its corona to millions of degrees Fahrenheit.

Educational experiences

What is making the corona so hot isn’t clear. A competing theory suggests that waves in the sun’s magnetic field carry energy from inside the sun to its atmosphere.

But the study’s actual findings aren’t its only important results. Lewandowski said her students were able to have opportunities that are rare for scientists and engineers so early in their careers — to learn first-hand about the collaborative and often-messy way that scientific research works in the real world.

“We still hear students talking about this course in the halls,” she said. “Our students were able to build a community and support each other at a time that was really tough.”

CU Boulder co-authors of the new study include Alexandra Werth, postdoctoral researcher at JILA; Colin West, teaching associate professor in physics; Allison Youngblood, astrophysicist at LASP now at the NASA Goddard Space Flight Center; Donald Woodraska, data systems team lead at LASP; and Courtney Peck, data systems software engineer at LASP and the Cooperative Institute for Research in Environmental Sciences (CIRES).

Funding for the research came from NASA through the MinXSS mission and the U.S. National Science Foundation through the STROBE Science & Technology Center and JILA Physics Frontier Center.

Tuberculosis infects more than 2 billion people in the world, and although tuberculosis is the most common co-infection in people living with HIV, previous studies have not examined how tuberculosis impacts HIV immune responses and virus characteristics.

This study suggest that tuberculosis may impact the efficacy of antibody based prevention and therapeutic strategies. Vaccines to elicit antibodies and antibodies are also being investigated as a means to treat and cure HIV. Higher prevalence of antibody resistant strains along with tuberculosis disease implies that these antibody-based interventions are more likely to in fail in these individuals.

“Tuberculosis is extremely common, especially in regions of the world with high levels of ongoing HIV transmission, and impacts both the immune responses and the characteristics of the circulating virus in people living with HIV so it is imperative we understand the relationship between the two,” said Manish Sagar, MD, an internist at Boston Medical Center and Professor of Medicine at Boston University Chobanian & Avedisian School of Medicine. “These studies have implications for HIV vaccines and antibody based HIV therapeutics.”

Researchers worked closely with investigators in Uganda and at the AIDS Clinical Trial Group (ACTG) to collect samples from people newly diagnosed with HIV that either did or did not have tuberculosis. From these individuals, they examined samples collected prior to and about 6 months after the start of HIV medications. Researchers compared antibodies, plasma inflammatory markers, and HIV sequences in the baseline and in treatment samples.

Tuberculosis disease is associated with higher prevalence of the some antibody resistant HIV. High ongoing HIV transmission in areas of the world with frequent tuberculosis disease suggest that a potential vaccine that elicits broad and potent antibodies may not work because these geographic regions are more likely to have antibody resistant strains.

Researchers highlight that this study has implications for HIV vaccine strategies as they aim to generate antibodies that can block the virus after exposure. Generating broad and potent HIV antibodies has not been accomplished and remains a monumental challenge. But Tuberculosis disease generates broadly potent antibody responses and dissecting biological pathways that provide insight into how tuberculosis enhances HIV antibody responses could be leveraged to develop novel strategies for eliciting broad and potent HIV antibodies.

Monitoring wildlife is one of the most costly and difficult aspects of conservation, and often depends on long-term observations in individual species.

But the study reveals a new and effective method.

It focusses on “interactions” between species, such as insects pollinating flowers or birds feeding on plants.

The results show that a small snapshot of interactions is a reliable indicator of the health of an entire community of species. Specifically, the study looked at whether these communities are “persistent” or not — meaning whether all species are fine or if any are declining to extinction.

The study was carried out by the University of Exeter, McGill University, the University of Toronto, Princeton University and MIT.

“All communities of plants and animals are supported by an underlying network of interactions between species,” said Dr Christopher Kaiser-Bunbury, from the Centre for Ecology and Conservation at Exeter’s Penryn Campus in Cornwall.

“Our study — which combines theory, statistics and real-world data — shows that examining a few of these interactions can provide ‘big picture’ conclusions about ecosystem health.

“This information is essential for policymakers, scientists and societies, as we try to tackle the global biodiversity crisis.”

When environmental conditions change, interactions between species often change too — providing an early indicator of wider problems.

As such, the study’s method can identify patterns more quickly than some traditional conservation monitoring — which is vital given the rapid changes being caused by human activity.

“Using minimal resources, we can rapidly assess both the persistence of entire ecological networks and the expected success of restoration,” said Dr Benno Simmons, also from Exeter’s Centre for Ecology and Conservation.

“Our method is especially effective at identifying when an ecological community is not persistent — allowing for rapid detection of extinction risk.”

As technology-driven capabilities in engineering and healthcare are ever-increasing, scientists and engineers are developing new technologies to advance the future of health. One such area, nanomedicine, explores the use of nanoparticles for drug delivery in the body to fight against infectious diseases or cancer. The assessment of these nanomedicines in cells, tissues and organs is often performed by optical imaging, which can have a limited quality of imaging resolution. New imaging technologies are needed to see nanoparticles in their 3-D ultrastructural context within biological tissues.

“To see nanomedicines in biological samples, researchers either use electron microscopy, which provides excellent spatial resolution but lacks 3-D imaging capabilities, or optical microscopy, which achieves excellent 3-D imaging, but exhibits relatively low spatial resolution,” Wilhelm said. “We demonstrate that we can perform 3-D imaging of biological samples with electron microscopy-like resolution. This technique, called super-resolution imaging, allows us to see nanomedicines inside individual cells. Using this new super-resolution imaging method, we can now start to track and monitor nanoparticles inside cells, which is a prerequisite for designing nanomedicines that are safer and more efficient in reaching certain areas within cells.”

The researchers applied a 3-D super-resolution imaging technique known as expansion microscopy which involves embedding cells within swellable hydrogels. Like water-absorbing materials used in diapers, the hydrogel materials physically expand up to 20-fold their original size upon contact with water.

“This expansion enables the imaging of cells with a lateral resolution of approximately 10 nanometers using a conventional optical microscope,” Wilhelm said. “We combined this method with an approach to image metallic nanoparticles within cells. Our approach exploits the inherent ability of metallic nanoparticles to scatter light. We used the scattered light to image and quantify nanoparticles inside cells without the need for any additional nanoparticle labels.”

The authors suggest their super-resolution imaging platform technology could be used to improve the engineering of safer and more effective nanomedicines to advance the translation of these technologies into the clinic.

This study creates a roadmap for understanding the many different ways that viruses could modify the effects of warming on communities of microbes. Viruses likely have strong effects on processes with microbes and the ways ecosystems function. Incorporating these previously ignored effects into ecosystem models will help scientists improve their predictions of how ecosystems could respond to climate change.

Microorganisms play integral roles in ecosystems by controlling the flow of energy and matter through processes like photosynthesis (carbon uptake), respiration (carbon release), and decomposition (carbon recycling). Climate change is currently altering how ecosystems function by changing how organisms operate within microbial food webs. Scientists know that viruses can have strong impacts on microbial processes, but they have less knowledge of how these impacts will change with future warming.

In this study, scientists from Duke University, the University of Tennessee Knoxville, the Netherlands Institute of Ecology, and Oak Ridge National Laboratory reviewed the potential impacts of warming on viruses and how these might alter scientific understanding of ecosystem responses to climate change. Warming likely affects several different stages of the viral infection cycle, as well as virus-host dynamics. However, there are still many gaps in our understanding about these effects. Because viruses are ubiquitous across all habitats and have strong effects on microbial functioning, filling these gaps is critical to understanding how warming will affect the flow of energy and matter within ecosystems. The researchers’ preliminary models show that viruses could potentially tip the scales on natural carbon balances, causing some ecosystems to switch from being net carbon sources (releasing more carbon than they store) to being net carbon sinks (absorbing carbon). This study shows how incorporating viruses into predictive models can lead to new and unexpected effects on ecosystems in response to climate change.

This work was supported by the Department of Energy Office of Science, Biological and Environmental Research program.

DNAzymes are nucleic acid enzymes that cut other molecules. Through chemistry, UCI’s team developed the Dz 46 enzyme, which specifically targets the allele-specific RNA mutation in the KRAS gene, the master regulator of cell growth and division, found in 25 percent of all human cancers. A description of how the team achieved this enzyme evolution was recently published in the online journal Nature Communications.

“Generating DNAzymes that can effectively function in the natural conditions of cell systems has been more challenging than expected,” said corresponding author John Chaput, UCI professor of pharmaceutical sciences. “Our results suggest that chemical evolution could pave the way for development of novel therapies for a wide range of diseases.”

Gene silencing has been available for more than 20 years and some FDA-approved drugs incorporate various versions of the technology, but none can distinguish a single point mutation in an RNA strand. The benefit of the Dz 46 enzyme is that it can identify and cut a specific gene mutation, offering patients an innovative, precision medicine treatment.

The DNAzyme resembles the Greek letter omega and acts as a catalyst by accelerating chemical reactions. The “arms” on the left and right bind to the target region of the RNA. The loop binds to magnesium, and folds and cuts the RNA at a very specific site. But generating DNAzymes with robust multiple turnover activity under physiological conditions required some ingenuity, because DNAzymes are normally very dependent on concentrations of magnesium not found inside a human cell.

“We solved that problem by re-engineering the DNAzyme using chemistry to reduce its dependency on magnesium and did so in such a way that we could maintain high catalytic turnover activity,” Chaput said. “Ours is one of the very first, if not the first, example of achieving that. The next steps are to advance Dz 46 to a point that it’s ready for pre-clinical trials.”

Team members Kim Thien Nguyen, project scientist, and Turnee N. Malik, postdoctoral scholar, both from the Department of Pharmaceutical Sciences, also participated in this study.

The researchers and UCI have filed provisional patent applications on the chemical composition and cleavage preference of Dz 46. Chaput is a consultant for drug development company 1E Therapeutics, which supported this work.