This month’s “Insights & Outcomes” casts its gaze to all corners of the scientific world, where Yale is conducting basic science research that may lead to dramatic, practical applications in the years to come.
We have items on the inner workings of nanowires, photosynthesis, and Tourette disorder. We also have items on the use of artificial intelligence in scientific writing, efforts to expand the availability of heart imaging, and a study about the brain’s response to certain sounds.
As always, you can find more science and medicine research news on Yale News’ Science & Technology and Health & Medicine pages.
Nanowires — some assembly required
Almost all living things breathe oxygen to get rid of excess electrons when converting nutrients into energy. Without access to oxygen, however, soil bacteria living deep under oceans or buried underground over billions of years have developed a way to eliminate electrons by “breathing minerals,” like snorkeling, through tiny protein filaments called nanowires.
In previous research, a team led by Nikhil Malvankar, associate professor of molecular biophysics and biochemistry at the Yale Microbial Sciences Institute, showed that nanowires are made up of a chain of heme molecules, just like hemoglobin in our blood, thrust into the environment to move electrons. But until now, no one had explained how individual bacteria made the nanowires.
A new study by researchers in the Malvankar lab now identifies the unique group of genes that help assemble the nanowire. Led by lab member Cong Shen, the team systematically analyzed the roles of key proteins that make up the nanowire assembly machinery, identifying the single machinery responsible for making the wire. By changing the amounts of key proteins in the machinery, the team made bacteria produce more nanowires and breathe faster.
The findings, published in the journal Cell Chemical Biology, mark an important next step in understanding the potential applications of bacterial nanowires in bioenergy, bioremediation, and bioelectronics for sensing environmental contaminants and mitigating climate change.
Other authors are lab members Aldo Salazar-Morales, Joey Erwin, Yangqi Gu, Anthony Coelho, Sibel Ebru Yalcin, and Fadel Samatey, along with Yale collaborators Kallol Gupta, and Wonhyeuk Jung.
Selective hearing
Sounds you consciously perceive affect your brain differently than sounds you don’t, a recent Yale study found.
For the study, researchers played participants a series of tones — ranging in intensity from undetectable to fully audible — over a white noise background. Sine the participants were also patients undergoing seizure monitoring, and therefore had electrodes implanted on the surface of the brain, this allowed the researchers to record detailed brain activity while the participants listened to the tones.
“We found that when sounds were consciously perceived, there was a wave of activity that flowed through widespread areas of the brain,” said Hal Blumenfeld, the Mark Loughridge and Michele Williams Professor of Neurology at Yale School of Medicine and senior author of the study, which was published in NeuroImage. “But when the same sounds were not consciously perceived, brain activity was limited to a small region around the auditory cortex.”
The activity was similar to what has been observed with visual perception, suggesting there are shared neural mechanisms between the two systems. The findings advance researchers’ understanding of what happens in the brain during sensory perception and shed light on the neurological underpinnings of human consciousness.
AI — a summary judgement
As researchers across disciplines continue to explore the potential benefits and applications of artificial intelligence (AI), Yale physicist Chiara M.F. Mingarelli recently tested the use of AI in scientific writing — and found both strengths and weaknesses.
While attending a two-week conference on the discovery of the gravitational wave background and its large amplitude, Mingarelli, an assistant professor of physics in the Faculty of Arts and Sciences (FAS), decided to use AI to create a summary of the conference. She uploaded conference transcripts to an AI platform and reviewed each new summary iteration with colleagues.
Mingarelli said that with each new iteration, the summary grew more detailed. But its deficiencies were “glaring,” she noted. At times it misinterpreted complex discussions, while also lacking in coherence and depth.
“At best, the document resembled a poorly written conference proceeding,” Mingarelli wrote in an op-ed describing the experience for the journal Nature Astronomy. “At worst, a tabloid version of our meeting.”
Cellular differences in Tourette patients
The biological roots of Tourette disorder occur in the basal ganglia, structures deep in the brain involved in the control of movement — particularly learned motor routines and habits. However, the role of individual cells in triggering the involuntary body and vocal tics that characterize the disorder have not been well understood.
A new single-cell analysis led by researchers at Yale School of Medicine and the Mayo Clinic, and published in the journal Biological Psychiatry has implicated several potential culprits associated with the disabling disorder, which affects as many as one in every 150 children.
The team led by corresponding author Flora Vaccarino, the Harris Professor at the Yale Child Study Center and professor of neuroscience at Yale School of Medicine, analyzed basal ganglia tissue from six individuals who had severe cases of Tourette disorder and compared those cells with tissue from six individuals without the disorder.
They found 50% fewer interneurons in the group with Tourette disorder. These interneurons are brain cells which suppress electrical activity within the basal ganglia to precisely modulate movements, which may explain motor hyperactivity in Tourette patients.
The researchers also found that medium spiny neurons — brain cells that make up 90% of cells in the basal ganglia — showed signs of metabolic stress in individuals with Tourette disorder. And finally, they observed that a type of immune system cells known as microglia showed increased inflammatory activity in basal ganglia tissue of those with the disorder; this inflammatory response, they found, was directly correlated with the metabolic stress in the medium spiny neurons.
“These factors create a pattern that may explain why individuals with Tourette disorder experience involuntary movements and vocalizations,” Vaccarino said.
Vaccarino also noted these cellular differences in Tourette patients appeared to be caused by changes in the expression of genes, not in alterations to the genes themselves.
“This insight opens up new directions for future research,” she said.
Yifan Wang of the Mayo Clinic and Liana Fasching of the Yale Child Study Center are the lead authors of the study.
In a heartbeat
Imaging is a vital tool for assessing the health and strength of the heart. In two recent studies, Yale researchers have explored how to bring critical imaging to more people and how to expand its application.
In the first, Yale researchers and collaborators at the National Institutes of Health evaluated whether a lower-strength, more affordable type of magnetic resonance imaging (MRI) scanner could be used effectively for cardiovascular imaging. The strength of MRI magnets is measured in Teslas (T), and most MRI scanners used in hospitals are 1.5T or 3.0T. For the study, published in the Journal of Cardiovascular Magnetic Resonance, Jie Xiang, a Ph.D. student in the Yale Graduate School of Arts and Sciences, applied a new data-acquisition method to the more affordable 0.55T MRI scanner. The researchers found that their method successfully boosted the signal that could be acquired, which could potentially enable more accurate imaging data.
“We think this will be the method of choice for measuring blood flow when these cheaper, more accessible MRI magnets begin to proliferate,” said Dana Peters, professor of radiology and biomedical imaging at Yale School of Medicine. “It improves the quality of measurements in these affordable scanners that will hopefully bring imaging to more individuals who need it.”
In the second study, published in Physiological Reports, Peters and her colleagues evaluated whether MRI could be used to assess diastolic dysfunction, a condition in which the heart doesn’t properly fill with blood as it beats.
“There is currently no MRI approach for detecting this very common and serious condition, responsible for 50% of heart failure,” said Peters. “Our group and others want to change that.”
When the researchers compared their MRI approach to the current standard of care for detecting diastolic dysfunction — ultrasound — they found it performed just as well, meaning MRI is an additional, highly sensitive tool with which clinicians can evaluate their patients.
Solving a photosynthesis mystery
A new Yale study aims to settle a longstanding question about photosynthesis, the process by which plants convert sunlight into fuel, with oxygen as a byproduct.
For 40 years, scientists have debated about a mechanism relating to Mn4Ca, a manganese “cofactor” within photosynthesis that acts like a high-performance solar battery. In that time, two schools of thought have emerged: those who think Mn4Ca’s storage mechanism works via a low-valence paradigm (LVP) and those who think it occurs via a high-valence paradigm (HVP). (Valence refers to an atom’s capacity to combine with other atoms.)
The distinction is important, researchers say, because it may affect how engineers try to mimic photosynthesis in solar technologies.
Jimin Wang, a research scientist in the Department of Molecular Biophysics and Biochemistry in FAS, lands definitively on the LVP side. In a new study in the Proceedings of the National Academy of Sciences, Wang conducted a Cryo-EM (cryogenic electron microscopy) analysis of proteins that contain Mn4Ca — an approach that Wang said gives a more accurate picture than other analytic techniques.
“Resolving the longstanding LVP/HVP controversy could help chemists and engineers to design biology-inspired solar capture devices with greatly improved efficiency,” Wang said.
James Shelton, Jon Atherton, Mallory Locklear, and Bill Hathaway contributed to this report.
Research Redux:
More accurate prognosis for lung cancer possible with new test, study shows
Hear ye! Hear ye! Yale researchers uncover new complexities in human hearing
Bullseye! Yale-led team finds a giant galaxy with a record nine rings
How do cells respond to changes? It’s not all in the genes
New study finds online advertising for compounded diabetes and weight-loss drugs may mislead consumers