Researchers combine classical and quantum optics for super-resolution imaging

A conceptual rendering of the super-resolution experiment, which will be enabled by a grant from the Chan Zuckerberg Initiative.
Illustration Credit: Courtesy of Colorado State University

The ability to see invisible structures in our bodies, like the inner workings of cells, or the aggregation of proteins, depends on the quality of one’s microscope. Ever since the first optical microscopes were invented in the 17th century, scientists have pushed for new ways to see things more clearly, at smaller scales and deeper depths.   

Randy Bartels, professor in the Department of Electrical Engineering at Colorado State University, is one of those scientists. He and a team of researchers at CSU and Colorado School of Mines are on a quest to invent some of the world’s most powerful light microscopes – ones that can resolve large swaths of biological material in unimaginable detail.   

The name of the game is super–resolution microscopy, which is any optical imaging technique that can resolve things smaller than half the wavelength of light. The discipline was the subject of the 2014 Nobel Prize in Chemistry, and Bartels and others are in a race to keep circumventing that diffraction limit to illuminate biologically important structures inside the body.  

New DNA Biosensor Could Unlock Powerful, Low-Cost Clinical Diagnostics

In a new study, researchers demonstrate the capability of DNA biosensor components for a unique modular DNA biosensor. The researchers plan to integrate their design within a device the size and shape of a smartphone for low-cost clinical diagnostics. 
Illustration Credit: N. Hanacek/NIST

DNA can signal the presence of or predisposition to a slew of diseases, including cancer. The ability to flag down these clues, known as biomarkers, allows medical professionals to make critical early diagnoses and provide personalized treatments. The typical methods of screening can be laborious, expensive or limited in what they can uncover. A new biosensor chip that boasts an accurate and inexpensive design may increase accessibility to high-quality diagnostics. 

The biosensor, developed by researchers at the National Institute of Standards and Technology (NIST), Brown University and the French government-funded research institute CEA-Leti, identifies biomarkers by measuring how binding occurs between DNA strands and the device. What sets it apart from other similar sensors is its modular design, which lowers costs by making it easier to mass produce and allowing the most expensive components to be reused. 

In a paper just posted online from the latest IEEE International Electron Devices Meeting, the researchers presented results of a study that demonstrates the device’s high sensitivity and precision despite its modularity, which is typically associated with diminished performance.

New enzyme could mean better drugs

A scientist works in the lab of Rice’s Xue Sherry Gao.
Photo Credit: Jeff Fitlow/Rice University

Just as a choreographer’s notation tells a dancer to strike a particular pose, an enzyme newly discovered by Rice University scientists is able to tell specific molecules precisely how to arrange themselves, down to the angle of single hydrogen bonds.

Biomolecular engineers at Rice identified a new Diels-Alderase (DAase), an enzyme that catalyzes the Diels-Alder reaction, a widely used method of synthesizing important materials and pharmaceuticals, from raw materials for plastics and fuels to synthetic steroids.

The enzyme, known as CtdP, was previously thought to be a different type of protein — a “regulator” controlling gene expression. Regulators typically do not serve a catalytic function, meaning they cannot “transform compound A into compound B,” said study co-author Xue Sherry Gao.

Mirror Image: FSU study lays out chirality flipping theory

Ken Hanson, left, and Eugene DePrince, right, are faculty members in the Department of Chemistry and Biochemistry.
Photo Credit: Florida State University

Chemists can make a career out of controlling whether certain molecules are generated as a lefty or a righty.

Molecules don’t literally have hands, but scientists often refer to them in this way when looking at molecules that are mirror images of each other and therefore are not superimposable. And whether a molecule is a lefty or a righty directly affects how they behave and their use in everything from drug design to flavoring foods.

A Florida State University research team led by Associate Professor of Chemistry Ken Hanson previously found a way to turn “left-handed” molecules into “right-handed” ones by using light to induce a proton transfer and the transformation into a different isomer. Now, Hanson and his fellow FSU Professor of Chemistry Eugene DePrince are harnessing the power of math and computers to predict what would happen if you performed that same process in a gap between closely spaced mirrors.

Parasite common in cats causes abortion in bighorn sheep

Bighorn sheep
Photo Credit: David Mark

A parasite believed to be present in more than 40 million people in the United States and often spread by domestic and wild cats could hamper ongoing conservation efforts in bighorn sheep.

A recent study led by Washington State University researchers at the Washington Animal Disease Diagnostic Laboratory found that Toxoplasma gondii, a parasite that infects most species of warm-blooded animals and causes the disease toxoplasmosis, is a cause of abortions, or pregnancy loss, as well as neonatal deaths in the sheep. Researchers documented five cases in bighorn sheep in a study published in the Journal of Wildlife Diseases, but additional studies are needed to determine the full scope of its impact, the authors said.

“We have seen Toxoplasma as a cause of fetal and neonate loss pretty commonly in domestic sheep, but we hadn’t seen pregnancy loss due to toxoplasmosis yet in bighorn sheep,” said Elis Fisk, the lead author of the study. “Unfortunately, it does appear to be causing abortions and some level of death in young bighorn lambs.”

Stress may trigger male defense against predators

Photo Credit: Jörgen Wiklund

Only males among the fish species crucian carp have developed a strategy to protect themselves from hungry predators, according to a new study from Lund University in Sweden. The explanation could lie in that the surrounding environment affects the stress system in males and females differently.

Some animals have evolved the ability to swiftly change appearance to defend themselves against predators when necessary - while avoiding the unnecessary costs of that appearance when it is not needed. This is an advantage for animals that live in environments where the risk of being eaten by predators varies. However, there is a difference in the ability of females and males to escape the enemy in this way. Researchers at Lund University have investigated the crucian carp fish species.

“When the smell of predatory fish spreads in the water, the male crucian carp begins to change its appearance, much like a character from Transformers. From having grown in length, the presence of the predatory fish causes the male carp to instead grow in height. The new body shape makes it much more difficult for gape-size limited predators to swallow them. The shape also provides better acceleration, which is an advantage when the fish has to escape from an attacking pike”, explains Jerker Vinterstare, biologist at Lund University.

Where you live and what cardiometabolic conditions you have affects risk of developing dementia

Image Credit: Gerd Altmann

People in the United States and England who have multiple cardiometabolic conditions such as diabetes and high systolic blood pressure are more likely to develop dementia than their peers who are relatively healthy, according to new research from the University of Surrey.

The study also found that people living in China have an increased risk of developing dementia if they have obesity and hypertension when compared to those in their country who are relatively healthy.

Panagiota Kontari, a post-graduate researcher in the School of Psychology at the University of Surrey, said:

“Dementia affects 55 million people worldwide and there is currently no cure, so prevention is key. Cardiometabolic conditions have been shown to increase likelihood of developing the syndrome due to their link with vascular, biological and neurodegenerative diseases, which might accelerate brain ageing and cognitive decline.

“Understanding how cardiometabolic conditions are clustered and which particular combination of them leads to a greater risk of dementia across the world is important as such knowledge could help design tailored prevention strategies that target varying risk factors in different countries.”

Propionic acid protects nerve cells and supports their regeneration

Thomas Grüter and Kalliopi Pitarokoili (right) from the study team in St. Josef Hospital.
Photo Credit: RUB, Marquard

Some autoimmune diseases attack the nerves in the arms and legs. Researchers from Bochum are taking a new approach to counteract this damage.

In laboratory tests, researchers from St. Josef Hospital Bochum showed that propionate, the salt of a short-chain fatty acid, can protect nerves and help with their regeneration. The findings could be useful for the treatment of autoimmune diseases that damage nerve cells, such as chronic inflammatory demyelinating polyneuropathy (CIDP). Propionate naturally arises in the intestine when fiber is broken down. In previous studies, a team from the same department from St. Josef Hospital Bochum, clinic of the Ruhr University Bochum, has already proven that people with multiple sclerosis (MS) have a lack of propionate and can benefit from additional propionate intake. Accordingly, the substance could also be useful for patients with CIDP.

A group led by Dr. Thomas Grüter and private lecturer Dr. Kalliopi Pitarokoili from the Neurological University Clinic on St. Josef Hospital (Head of Prof. Dr. Ralf Gold), in the journal Proceedings of the National Academy of Sciences.

Genes Common to Different Species Found to Be Connected to the Development of Depression

Affective disorders, also known as mood disorders, are a group of mental illnesses that involve changes in emotional states.
Photo Credit:: Christopher Lemercier

Russian scientists performed a cross-species analysis of brain gene expression in danio fish, rats and humans to identify new common molecular targets for the therapy of affective disorders of the central nervous system induced by chronic stress. The study was able to identify several key brain proteins that may play important roles in the pathogenesis of affective disorders.

The article was published in the journal Scientific Reports. Affective disorders, also known as mood disorders, are a group of mental illnesses that involve changes in emotional states. They include various forms of depression and mania, psychosis, and increased anxiety. They are widespread because they occur not only as independent mental pathologies, but also as complications of neurological and other somatic diseases.

This fact determines the difficulty of diagnosis: people classify low mood, anxiety and irritability as temporary, situational manifestations. According to statistics, emotional disorders of varying severity occur in 20% of people, but only a quarter of them receive qualified help.

A Quan­tum Video Reel

Using all of images from the video reel, the team could then estimate the quantum states of the atom.
Image Credit: University of Innsbruck

When it comes to creating ever more intriguing quantum systems, a constant need is finding new ways to observe them in a wide range of physical scenarios.  JILA Fellow Cindy Regal and JILA and NIST Fellow Ana Maria Rey have teamed up with Oriol Romero-Isart from the University of Innsbruck and IQOQI to show that a trapped particle in the form of an atom readily reveals its full quantum state with quite simple ingredients, opening up opportunities for studies of the quantum state of ever larger particles.

In the quantum realm an atom does not behave as point particle, instead it behaves more as a wave.  Its properties (e.g., its position and velocity) are described in terms of what is referred to as the wavefunction of the atom. One way to learn about the wavefunction of a particle is to let the atom fly and then capture its location with a camera. 

And with the right tricks, pictures can be taken of the particle’s quantum state from many vantage points, resulting in what is known as quantum tomography (‘tomo’ being Greek for slice or section, and ‘graphy’ meaning describing or recording).  In the work published in Nature Physics, the authors used a rubidium atom placed carefully in a specific state of its motion in a tightly focused laser beam, known as an optical tweezer.  And they were able to observe it from many vantage points by letting it evolve in the optical tweezer in time.  Like a ball rolling in a bowl, at different times the velocity and location of the particle interchange, and by snapping pictures at the right time during a video reel of the ball, many vantages of the particle’s state can be revealed.