In 2015, a submarine volcano in the South Pacific erupted, forming the Hunga Tonga Hunga Ha’apai island, destined to a short, seven-year life. A research team led by the University of Colorado Boulder and Cooperative Institute for Research in Environmental Sciences (CIRES) jumped on the rare opportunity to study the early microbial colonizers of a newly formed landmass and to their surprise, the researchers discovered a unique microbial community that metabolizes sulfur and atmospheric gases, similar to organisms found in deep sea vents or hot springs.

“These types of volcanic eruptions happen all over the world, but they don’t usually produce islands. We had an incredibly unique opportunity,” said Nick Dragone, CIRES PhD student and lead author of the study published this month in mBio. “No one had ever comprehensively studied the microorganisms on this type of island system at such an early stage before.”

“Studying the microbes that first colonize islands provides a glimpse into the earliest stage of ecosystem development — before even plants and animals arrive,” said Noah Fierer, CIRES fellow, professor of ecology and evolutionary biology at CU Boulder and corresponding author on the study.

A multi-institutional team of researchers on the ground collected soil samples from the island, then shipped them to CU Boulder’s campus. Dragone and Fierer could then extract and sequence DNA samples from the samples.

“We didn’t see what we were expecting,” said Dragone. “We thought we’d see organisms you find when a glacier retreats, or cyanobacteria, more typical early colonizer species — but instead we found a unique group of bacteria that metabolize sulfur and atmospheric gases.”

And that wasn’t the only unexpected twist in this work: On January 15, 2022, seven years after it formed, the volcano erupted again, obliterating the entire landmass in the largest volcanic explosion of the 21st century. The eruption completely wiped out the island and eliminated the option for the team to continue monitoring their site.

“We were all expecting the island to stay,” said Dragone. “In fact, the week before the island exploded we were starting to plan a return trip.”

However, the same fickle nature of the Hunga Tonga Hunga Ha’apai (HTHH) that made it explode also explains why the team found such a unique set of microbes on the island. Hunga Tonga was volcanically formed, like Hawaii.

“One of the reasons why we think we see these unique microbes is because of the properties associated with volcanic eruptions: lots of sulfur and hydrogen sulfide gas, which are likely fueling the unique taxa we found,” Dragone said. “The microbes were most similar to those found in hydrothermal vents, hot springs like Yellowstone, and other volcanic systems. Our best guess is the microbes came from those types of sources.”

The expedition to HTHH required close collaboration with members of the government of the Kingdom of Tonga, who were willing to work with researchers to collect samples from land normally not visited by international guests. Coordination took years of work by collaborators at the Sea Education Association and NASA: a Tongan observer must approve and oversee any sample collection that takes place within the Kingdom.

“This work brought in so many people from around the world, and we learned so much. We are of course disappointed that the island is gone, but now we have a lot of predictions about what happens when islands form,” said Dragone. “So if something formed again, we would love to go there and collect more data. We would have a game plan of how to study it.”

“There is no cure yet for many devastating brain disorders,” says Shaoqin “Sarah” Gong, UW-Madison professor of ophthalmology and visual sciences and biomedical engineering and researcher at the Wisconsin Institute for Discovery. “Innovative brain-targeted delivery strategies may change that by enabling noninvasive, safe and efficient delivery of CRISPR genome editors that could, in turn, lead to genome-editing therapies for these diseases.”

CRISPR is a molecular toolkit for editing genes (for example, to correct mutations that may cause disease), but the toolkit is only useful if it can get through security to the job site. The blood-brain barrier is a membrane that selectively controls access to the brain, screening out toxins and pathogens that may be present in the bloodstream. Unfortunately, the barrier bars some beneficial treatments, like certain vaccines and gene therapy packages, from reaching their targets because in lumps them in with hostile invaders.

Injecting treatments directly into the brain is one way to get around the blood-brain barrier, but it’s an invasive procedure that provides access only to nearby brain tissue.

“The promise of brain gene therapy and genome-editing therapy relies on the safe and efficient delivery of nucleic acids and genome editors to the whole brain,” Gong says.

In a study recently published in the journal Advanced Materials, Gong and her lab members, including postdoctoral researcher and first author of the study Yuyuan Wang, describe a new family of nano-scale capsules made of silica that can carry genome-editing tools into many organs around the body and then harmlessly dissolve.

By modifying the surfaces of the silica nanocapsules with glucose and an amino acid fragment derived from the rabies virus, the researchers found the nanocapsules could efficiently pass through the blood-brain barrier to achieve brain-wide gene editing in mice. In their study, the researchers demonstrated the capability of the silica nanocapsule’s CRISPR cargo to successfully edit genes in the brains of mice, such as one related to Alzheimer’s disease called amyloid precursor protein gene.

Because the nanocapsules can be administered repeatedly and intravenously, they can achieve higher therapeutic efficacy without risking more localized and invasive methods.

The researchers plan to further optimize the silica nanocapsules’ brain-targeting capabilities and evaluate their usefulness for the treatment of various brain disorders. This unique technology is also being investigated for the delivery of biologics to the eyes, liver and lungs, which can lead to new gene therapies for other types of disorders.

Animals that live in highly variable environments play a similar lottery when it comes to their Darwinian fitness, or how well they are able to pass on their genes. In a new study led by the University of Michigan, scientists found that red squirrels that gambled at the game of reproduction outperformed their counterparts, even if it cost them in the short term.

Natural selection favors female squirrels that have large litters in years when food is abundant because they contribute lots of babies to the gene pool, said Lauren Petrullo, lead author and National Science Foundation postdoctoral research fellow in biopsychology at the University of Michigan.

“We were surprised to find that some females have large litters in years when there won’t be enough food for their babies to survive the winter,” she said. “Because it’s biologically expensive to produce offspring, we wanted to know why these females make what appears to be an error in their reproductive strategy.”

The red squirrels studied live in the Canadian Yukon and experience a “mast year,” or boom in their main food source — seeds from the cones of white spruce trees — once every four to seven years. Squirrels forecast the large mast crop of food before it occurs and increase litter sizes in the months prior, ensuring better future survival for their babies and better fitness for themselves.

“There is a constant tug-of-war between the trees and the squirrels at our study site,” Petrullo said, “with each player trying to deceive the other for its own fitness gain.”

Petrullo and Ben Dantzer, U-M associate professor of psychology and of ecology and evolutionary biology, used data collected by the Kluane Red Squirrel Project, a collaborative, 34-year-old field study involving U-M, the University of Colorado, the University of Alberta and the University of Saskatchewan.

“Each year, we collect data on how many babies squirrels produce and how many spruce cones the squirrels eat,” Dantzer said.

The scientists quantified the reproduction of female squirrels during both food booms and busts, discovering differences in their fitness whether they gambled with their reproductive strategy or not. While some squirrels played it safe by keeping litter sizes small each year, those that took a “pie in the sky” approach by having large litters even when food was scarce enjoyed greater lifetime fitness if they got to experience a mast year, the research showed.

Unlike the Powerball example, though, squirrels aren’t guaranteed to eventually win.

“In some ways, this strategy of gambling with litter sizes is like playing with fire,” Petrullo said. “Because the average squirrel lifespan is 3.5 years and masts only happen every four to seven, a female could potentially be sabotaging her fitness by having too many babies in low-food years, hoping for a mast when she may die before she ever gets to experience a mast at all. This could be pretty costly.”

Alternatively, for squirrels, the cost of not gambling at all in the game of reproduction can be insurmountable if they end up missing their shot at the jackpot.

“It’s essentially impossible for a female to recuperate the fitness costs of not ramping up reproduction in a mast year, so the stakes are extremely high,” Petrullo said.

Females that increased litter sizes in low-food years did take a short-term hit to their fitness. But they were more likely to increase litter sizes if and when they experienced a mast, taking home the ultimate prize of greater lifetime reproductive success, she said.

The squirrels’ best bet, according to the researchers, is to take their chances and suffer short-term fitness costs in order to avoid the unmatched cost of missing the fitness jackpot completely.

“Determining the relative costs of different types of errors is key to understanding why animals make what look to us like mistakes,” Petrullo said.

Scientists are still unsure exactly how the squirrels are able to forecast future food production. The animals may be eating parts of the spruce trees that affect their physiology and alter the number of babies they produce, Dantzer said.

“This is exciting because it suggests that squirrels are eavesdropping on the trees, but we still have much more to do to solve this puzzle,” he said.

Because many animals use cues about things like food in their environment to make reproductive decisions, and the reliability of these cues is declining due to global climate change, scientists also wonder how the costs of these types of errors will alter what is the best reproductive strategy.

“If the predictability of a food boom is reduced and squirrels can no longer forecast the future, this could impact the number of squirrels out there in the Boreal forest,” Dantzer said. “This could be problematic given that squirrels are prey for many predators.”

The research, which appears in Science, was funded in part by the National Science Foundation and the Natural Sciences and Engineering Research Council of Canada.

The study’s co-authors are Stan Boutin, University of Alberta; Andrew McAdam, University of Colorado; and Jeff Lane, University of Saskatchewan.