Category: Science

A range of commonly prescribed antidepressants can increase bacteria’s resistance to antibiotic medications, a new study finds.

The researchers focused on prescription drugs used to treat depressive disorders, anxiety disorders, and other psychological conditions.

More than 42 million prescriptions were dispensed for antidepressant medications in Australia in 2021 and the researchers investigated bacterial exposure to five of the most common drugs: sertraline (Zoloft), escitalopram (Lexapro), bupropion (Welbutrin), duloxetine (Cymbalta), and agomelatine (Valdoxan).

“While the overuse of antibiotics is acknowledged as the major driver of bacterial resistance, we wanted to investigate if other common medications were contributing to the problem,” says Jianhua Guo, a professor at the University of Queensland’s Australian Centre for Water and Environmental Biotechnology.

“Sertraline, duloxetine, and fluoxetine had the strongest impact on bacterial resistance to antibiotics among the drugs we tested. Our study showed a marked increase in antibiotic resistance from those three, even at very low doses.

“Notably, the antibiotic resistance appears to be antidepressant-dependent, which may be due to oxidative stress in bacteria posed by antidepressants. Further studies need to evaluate the potential effects on the microbiomes of people given antidepressants and assess their risk gastrointestinal disturbances or diseases.”

It is estimated 1.27 million people die every year from infections which do not respond to medication and the figure is predicted to reach 10 million by 2050 unless global action is taken.

The study, published in the Proceedings of the National Academy of Sciences, was funded by the Australian Research Council Discovery Project, and the UQ Foundation Research Excellence Awards.

Source: University of Queensland

Under more severe climate warming scenarios, the inventory of trees used for timber in the continental United States could decline by as much as 23% by 2100.

The largest inventory losses would occur in two of the leading timber regions in the US, which are both in the South.

The findings show modest impacts on forest product prices through the end of the century, but suggest bigger impacts in terms of storing carbon in US forests, the researchers say. Two-thirds of US forests are classified as timberlands.

“We already see some inventory decline at baseline in our analysis, but relative to that, you could lose, additionally, as much as 23% of the US forest inventory,” says the study’s lead author Justin Baker, associate professor of forestry and environmental resources at North Carolina State University. “That’s a pretty dramatic change in standing forests.”

In the study, published in Forest Policy and Economics, researchers used computer modeling to project how 94 individual tree species in the continental United States will grow under six climate warming scenarios through 2100.

They also considered the impact of two different economic scenarios on demand growth for forestry products. The researchers compared their outcomes for forest inventory, harvest, prices and carbon sequestration to scenarios with no climate change.

The researchers say their methods could provide a more nuanced picture of the future forest sector under high-impact climate change scenarios compared to other models.

“Many past studies show a pretty optimistic picture for forests under climate change because they see a big boost in forest growth from additional carbon dioxide in the atmosphere,” Baker says.

“The effect that carbon dioxide has on photosynthesis in some of those models tends to outweigh the losses you see from precipitation and temperature induced changes in forest productivity and tree mortality. We have a model that is specific to individual tree species, and that allows us to better understand how climate factors influence growth rates and mortality.”

The researchers found that in certain regions trees would grow more slowly in higher temperatures, and die faster. Combined with increasing harvest levels and greater development pressures, that led to declines in the total tree inventory. They projected the largest losses would be in the Southeast and South-Central regions, which are two of the three most productive timber supply regions in the US.

Those regions could see tree inventories shrink by as much as 40% by 2095 compared to one of their baseline scenarios. Due to declines in pine products, the researchers projected softwood lumber prices could increase as much as 32% by 2050.

“We found pretty high levels of sensitivity to warming and precipitation changes for productive pine species in the South, especially when climate change is combined with high forest product demand growth,” Baker says.

However, the researchers projected gains in tree supplies in the Rocky Mountain and Pacific Southwest regions, driven by higher rates of death of certain trees that lead to larger harvests initially, followed by the growth of more heat-tolerant species.

“These are regions losing a lot of inventory right now due to pests and fire disturbance,” Baker says. “What you’re seeing is a higher level of replacement with climate adaptive species like juniper, which are more tolerant to future growing conditions.”

Combining the effects from all the regions, the researchers projected total losses of US tree inventory of 3 to 23% compared to baseline. They projected losses in carbon sequestration in most scenarios, and estimated the value of lost carbon stored in US forests up to $5.5 billion per year.

They found the economic impact of climate change on the overall US forest products industry value could range from a loss of as much as $2.6 billion per year—representing 2.5% of the value of the industry—or a gain in value of more than $200 million per year.

“We saw that the markets could be more resilient than the forests themselves,” Baker says. “Your market effects may seem modest in terms of the effect it has on the consumers and producers, but those impacts are small compared to the carbon sequestration value that forests provide on an annual basis.”

The researchers say more studies are needed to bring the future of US forestry into sharper focus.

“We don’t know a lot about how disturbance-related mortality or loss in tree productivity is going to bear out across the landscape as temperatures get warmer,” Baker says. “We did our best to address a couple pieces of the puzzle with temperature and precipitation changes, and interactions between climate and market demand, but a lot more work needs to be done to get a good handle on climate change and forestry.”

The US Environmental Protection Agency funded the work. The views and opinions expressed in this paper are those of the authors alone and do not necessarily state or reflect those of the EPA, and no official endorsement should be inferred.

Source: NC State

Toward the end of her life, the Austrian-born Jewish scientist Rudolphina Menzel acknowledged a horrifying reality: the dog-training techniques she pioneered had been used by the Nazis to commit atrocities.

“I suffered a lot knowing that my students in Austria and Germany were using the knowledge they acquired from me to use dogs to exterminate my people and other peoples,” she said in an interview roughly 10 years before her death in 1973.

“She had to constantly negotiate a shifting kaleidoscope of political, scientific, and cultural considerations…”

But in one of the more remarkable ironies of 20th-century history, Menzel also trained the dogs that helped create the state of Israel. She was a trailblazing Zionist pioneer.

A new book, Canine Pioneer: The Extraordinary Life of Rudolphina Menzel (Brandeis Press, 2023), chronicles Menzel’s life and career, exploring her seminal role in the development of cynology (the scientific study of the domestic dog) and modern Jewish, European, and Middle Eastern history.

Edited by the anthropologist Susan M. Kahn, the book details Menzel’s role in training the dogs used by the German military and police in the 1920s and early 1930s—and how she helped the fledgling Zionist state secure its independence from Britain and win the 1948 Arab-Israeli War.

“Rudolphina’s long, complicated, and eventful life was peppered with triumphs, marred by tragedies, and suffused with ideological tensions,” Kahn writes. “She had to constantly negotiate a shifting kaleidoscope of political, scientific, and cultural considerations in order to realize her extraordinarily ambitious scientific goals and activist objectives.”

Zionist and scientist

Menzel was born in 1891 to an upper-middle-class, assimilated Jewish Viennese family.

During childhood, she chanced on a discarded copy of the Zionist newspaper Die Welt and developed what became a lifelong commitment to the cause. By the time she earned her doctorate in chemistry from the University of Vienna in 1914, she was also an ardent socialist.

After she and her husband Rudolph settled in the northern Austrian city of Linz following World War I, Menzel met Austrian veterinarian and renowned dog breeder Joseph Bodingbauer. He gave the Menzels their first dog, a robust, brindle-colored boxer she named Mowgli.

Kahn details how and why Menzel transformed her love of dogs into a serious professional undertaking that enabled her to investigate scientific questions and solve societal problems.

She quickly mastered the burgeoning scientific field of cynology and designed an original, 16-year research study where she observed and recorded the daily behaviors of hundreds of boxers, taking note of which behavioral traits were genetic and how the environment shaped their temperament.

She also became fascinated with the dimensions of canine perception, particularly olfaction. In a landmark 1930 paper, she demonstrated that with the right training, dogs could discern the individual scents of particular human beings. She then trained her dogs to recognize a person’s smell at different times and under different conditions, making them ideal for tracking criminals and suspects.

Rise of the Nazis

Inevitably, Menzel’s work drew the interest of the German and Austrian police and military. She worked as a sought-after consultant and lectured to both groups on her techniques for breeding and training dogs that were obedient, intelligent, and skilled at police work.

It was standard practice to train police dogs in a foreign language so criminals or prisoners could not communicate with them. Menzel, whose Zionism inspired her to learn Hebrew, trained her dogs to obey commands in the language.

In 1934, a year after Hitler came to power, Menzel stopped working for Austria and Germany. But her dogs and training methods remained used by authorities well after the Nazis rose to power. It’s likely that some of the hounds deployed by the Nazis were, at least originally, trained to obey commands in Hebrew.

After the Nazis annexed Austria in 1938, local authorities in Menzel’s hometown ordered the “immediate removal of the Jewish kennel” on her property. In August of that year, she and her husband fled to Palestine with forged papers, taking only two of their hundreds of boxers.

Menzel in Palestine

Many early Zionist settlers were socialists and considered having pets a bourgeois habit out of keeping with the pioneering ethos. In addition, Jews in general had long had an ambivalent relationship with the canine species. The Hebrew Bible and the rabbinical commentaries in the Talmud depict dogs as unclean. In Eastern Europe, “du bist a hunt mit di oyern”—”you are a dog with ears” in Yiddish—was considered one of the worst insults.

Menzel changed all this by persuading Zionists that dogs could be much more than pets. They could be workers that protected Jewish lives and property. “Help us reclaim the dog for our people,” she wrote to her fellow Jews in Palestine in 1943. “Make room for a new pioneering path to reclaim the dog for the building of our country.”

Many of the dogs in Palestine were feral and free-roaming. Menzel, who coined the term Canaan dogs to describe them, bred and trained them. She discovered that some of these so-called “pariah dogs” could be loyal, intelligent, resourceful, and forgiving.

During World War II, Menzel worked with the British, equipping them with dogs to detect the mines the Germans laid in North Africa. But she made them promise never to use the animals against the Jews in Palestine, still under British control.

Menzel’s dogs were also used to detect intruders and patrol Jewish land, protecting against the Palestinians fighting Zionist settlers. When the 1948 war broke out against the surrounding Arab nations, her dogs were deployed by the Haganah, the main Zionist military organization. They transported messages by following scent trails laid between command centers and soldiers in the field. They also carried medical supplies and ammunition in saddles on their backs.

Columns of military dogs marched through the streets of Haifa and Tel Aviv in the 1949 victory parades.

Dogs “were tools that built the country no less than the plow, the tractor, the gun, and the water tower,” Menzel later wrote.

A change of focus

In the early 1950s, Menzel radically shifted the focus of her work and began training seeing-eye dogs. She founded the Israel Institute for Orientation and Mobility of the Blind, the first guide-dog institute in the Middle East and undertook extensive studies of the mobility needs of people with visual disabilities in Israel.

Menzel’s death went largely unnoticed, and her contributions to cynology were all but forgotten. This may be because of sexism or because most of her scientific work was never translated into English and failed to find a broader audience.

Kahn sees her book as an important first step to lifting Rudolphina Menzel out of obscurity.

Source: Brandeis University

Higher temperatures cause a pathogenic fungus known as Cryptococcus deneoformans to turn its adaptive responses into overdrive, research finds.

This increases its number of genetic changes, some of which might presumably lead to higher heat resistance, and others perhaps toward greater disease-causing potential.

Bacteria and viruses have been drivers of deadly global pandemics and annoying infections. But the pathogens we haven’t had to reckon with as much—yet—are the fungi.

Pathogenic fungi (Candida, Aspergillus, Cryptococcus, and others) are notorious killers of immune-compromised people. But for the most part, healthy people have not had to worry about them, and the vast majority of the planet’s potentially pathogenic fungi don’t do well in the heat of our bodies.

But all that may be about to change.

The findings show that higher heat makes more of the fungus’ transposable elements, or jumping genes, get up and move around within the fungal DNA, leading to changes in the way its genes are used and regulated. The findings appear in the Proceedings of the National Academy of Sciences.

“These mobile elements are likely to contribute to adaptation in the environment and during an infection,” says Asiya Gusa, postdoctoral researcher in molecular genetics and microbiology in the Duke University School of Medicine. “This could happen even faster because heat stress speeds up the number of mutations occurring.”

This may ring a bell with viewers of the new HBO series The Last of Us, where a dystopian hellscape is precipitated by a heat-adapted fungus that takes over humans and turns them into zombies. “That’s exactly the sort of thing I’m talking about—minus the zombie part!” says Gusa, who just watched the first episode and who will join the Duke faculty as an assistant professor later this year.

“These are not infectious diseases in the communicable sense; we don’t transmit fungi to each other,” Gusa says. “But the spores are in the air. We breathe in spores of fungi all the time and our immune systems are equipped to fight them.”

Fungal spores are generally larger than viruses, so your existing stock of face masks against COVID would probably be sufficient to stop them. That, and your body heat, for now.

“Fungal diseases are on the rise, largely because of an increase in the number of people who have weakened immune systems or underlying health conditions,” Gusa says. But at the same time, pathogenic fungi may be adapting to warmer temperatures as well.

Working in the lab of professor Sue Jinks-Robertson, Gusa led research that focused on three transposable elements that were particularly active under heat stress in C. deneoformans. But there are easily another 25 or more transposable elements in that species that could mobilize, she says.

The team used “long-read” DNA sequencing to see changes that might otherwise have been missed, Gusa says. Computational analysis allowed them to map transposons and then see how they had moved. “We have improved tools now to see these movements that were previously hiding in our blind spots.”

Heat stress sped the mutations up. Following 800 generations of growth in laboratory medium, the rate of transposon mutations was five-times higher in fungi raised at body temperature (37 Celsius) compared with fungi raised at 30C.

One of the transposable elements, called T1, had a tendency to insert itself between coding genes, which could lead to changes in the way genes are controlled. An element called Tcn12 often landed within the sequence of a gene, potentially disrupting that gene’s function and possibly leading to drug resistance. And a third kind, Cnl1, tended to land near or in the telomere sequences at the ends of chromosomes, an effect which Gusa says isn’t fully understood.

The mobilization of transposable elements also appeared to increase more in fungi living in mice than in lab culture. “We saw evidence of all three transposable elements mobilizing in the fungus genome within just ten days of infecting the mouse,” Gusa says. The researchers suspect that the added challenges of surviving in an animal with immune responses and other stressors may drive the transposons to be even more active.

“This is a fascinating study, which shows how increasing global temperature may affect the fungal evolution in unpredictable directions,” says Arturo Casadevall, chair of molecular microbiology and immunology at Johns Hopkins University. “As the world warms, transposons in soil fungi like Cryptococcus neoformans could become more mobile and increase genomic changes in ways that could enhance virulence and drug resistance. One more thing to worry about with global warming!”

The next phase of this research will be looking at pathogens from human patients who have had a relapsing fungal infection. “We know that these infections can persist and then come back with potential genetic changes.”

It’s time to get serious about pathogenic fungi, Gusa says. “These kinds of stress-stimulated changes may contribute to the evolution of pathogenic traits in fungi both in the environment and during infection. They may be evolving faster than we expected.”

The National Institutes of Health supported the research.

Source: Duke University

New research uncovers a source of inaccuracy in custom satisfaction surveys.

Customer satisfaction surveys blip into our daily lives after dental appointments, haircuts, and calls with IT. For businesses, these short questionnaires are intended to provide feedback and make improvements.

But the findings demonstrate that perceptions of customer service don’t always align with the actual service provided. Results from three studies found consumers belonging to underrepresented racial and ethnic groups rated poorer quality service less negatively than white consumers did.

“Our research shows that perhaps we need to move beyond assumptions and not just rely on a five-point customer satisfaction survey to help address discrimination,” says Samantha Cross, associate professor of marketing at Iowa State University and coauthor of the paper in the Journal of the Association for Consumer Research.

Cross explains that employees have assumptions as to whether someone is a viable customer, and the customer has assumptions about good service. These assumptions come from our specific backgrounds and experiences and the treatment of our wider ethno-racial group in society.

Customers who have experienced poor service more frequently in the past may have lower expectations than those who have not. Someone with an already low bar may rate an interaction with an employee as acceptable while someone with a high bar rates it as unacceptable.

Cross and her coauthors say these differences make it harder to catch unfair treatment through customer satisfaction surveys—especially in financial services.

“When you’re in line at a grocery store, you can see how other people are being treated and compare it to your treatment. You also have the ability to compare your experience with previous interactions at grocery stores,” says Cross. “That’s much harder if you’re applying for a loan or buying a car for the first time.”

Unlike the grocery store example, interactions with financial service providers tend to be one-on-one, behind closed doors.

The authors emphasize that differences in service can have long-lasting impacts, even when customers don’t perceive discrimination. Along with the possibility of becoming desensitized, indifferent, or accepting of poorer treatment, customers could miss out on a loan to start a business or face more hurdles to get a mortgage.

Bank visits

In the first study, the researchers selected nine male participants of similar age, height, body build, attractiveness, and education who were all small business owners in Los Angeles, California. The participants understood basic business and banking terminology and were knowledgeable about the local economy. Three were Black; three were Hispanic; three were white.

The participants wore identical clothing, including a shirt with an embedded video camera, and visited banks to request a $60,000 to $70,000 loan for a fictional computer service business. The university institutional review board and state attorney general’s office in California consented to the recording of the interactions between the study participants and bank officers. The participants went to multiple banks and completed a survey after each visit (e.g., level of assistance they received, types of information provided.)

Survey results from a total of 69 bank visits showed overall satisfaction was consistent across the Black, Hispanic, and white participants. But when the researchers analyzed the video recordings frame-by-frame, they found significant differences in the interactions.

Black and Hispanic participants often waited longer at banks to meet with the lender and received less one-on-one time than their white counterparts. Bank loan officers, 90% of whom were white, more often gave white participants a handshake and asked their name (80%) compared to Black and Hispanic participants (63% and 66%, respectively.)

Loan officers were also more likely to offer the white participants a seat and maintain eye contact with them compared to the Black and Hispanic participants. White participants more often received an application, documents about the bank’s interest and fees, and other sales-pitch statements at the end of the meeting. In the encounters where loan officers appeared to have the same racial background as the Black and Hispanic participants, the researchers say the interactions were more welcoming and friendlier.

Customer service on video

In the second study, the researchers showed 83 participants a two-minute video from the first study of a strongly negative interaction with a white bank officer. The participants did not know the racial or ethnic background of the participant from the first study who was in the room with the bank officer. They then filled out a scaled survey about the behavior of the bank officer and shared their own basic demographic data.

The researchers found participants who identified as belonging to an underrepresented ethno-racial group evaluated the strongly negative service encounter less negatively than white consumers.

A similar experiment with 240 participants and two short videos (i.e., one positive encounter, the other negative) showed similar results. With the negative interaction, participants from underrepresented ethno-racial groups rated the encounter higher than white participants. With the positive interaction, there was no significant difference in the ratings.

“Research uncovers and dissects, and then we have to decide what do we do with it,” says Cross.

To help ensure customers are being treated the same, Cross and her coauthors say managers could train employees to follow “behavioral scripts.” This could be as simple as making sure all customers receive a friendly greeting, wait within a certain time frame, and receive the same handouts.

The researchers say employee performance evaluations could also include video or audio recordings of their interactions with customers. A third party could review the employee’s tone of voice, facial expressions, and other nonverbal cues to discuss improvements. Recordings could also be useful in training sessions to discuss microaggressions.

Source: Iowa State University

Young adults who feel down or depressed are more likely to develop cardiovascular disease and have poor heart health, according to a new study.

The researchers analyzed data from more than a half million people between the ages of 18 and 49. Their findings add to a growing body of evidence connecting cardiovascular disease (CVD) with depression among young and middle-aged adults, and suggest the relationship between the two could begin in early adulthood.

The study in the Journal of the American Heart Association also found that young adults who self-reported feeling depressed or having poor mental health days had higher rates of heart attacks, strokes, and risk factors for heart disease compared with their peers without mental health issues.

“When you’re stressed, anxious, or depressed, you may feel overwhelmed, and your heart rate and blood pressure rises. It’s also common that feeling down could lead to making poor lifestyle choices like smoking, drinking alcohol, sleeping less, and not being physically active—all adverse conditions that negativity impact your heart,” says Garima Sharma, associate professor of medicine at Johns Hopkins Medicine and senior author of the study.

Sharma and her colleagues looked at data from 593,616 adults who participated in the Behavioral Risk Factor Surveillance System, a self-reported, nationally representative survey conducted between 2017 and 2020.

The survey included questions about whether they have ever been told they have a depressive disorder, how many days they experienced poor mental health in the past month (0 days, 1–13 days, or 14–30 days), whether they had experienced a heart attack, stroke, or chest pain, and if they had cardiovascular disease risk factors.

Risk factors include high blood pressure, high cholesterol, being overweight/obese, smoking, diabetes, and poor physical activity and diet. People who had two or more of these risk factors were considered to have suboptimal cardiovascular health.

One in five adults self-reported having depression or frequently feeling low, with the study noting that there could have been higher rates during the last year of the study, which was the first year of the COVID-19 pandemic.

According to the US Centers for Disease Control and Prevention, the percentage of US adults who experienced depression or anxiety jumped from 36.4% to 41.5% during the first year of the pandemic, with the highest spike among people ages 18 to 29.

The study revealed that, overall, those who self-reported several days of feeling down had a stronger link to cardiovascular disease and poor heart health. Compared with people who reported no poor mental health days in the past 30 days, participants who reported up to 13 poor mental health days had 1.5 times higher odds of CVD, while those with 14 or more days of poor mental health had double the odds. Associations between poor mental health and CVD did not differ significantly by gender or urban/rural status.

“The relationship between depression and heart disease is a two-way street. Depression increases your risk of heart issues, and those with heart disease experience depression,” says lead author Yaa Adoma Kwapong, a postdoctoral research fellow at Johns Hopkins Ciccarone Center for the Prevention of Cardiovascular Disease.

“Our study suggests that we need to prioritize mental health among young adults and perhaps increase screening and monitoring for heart disease in people with mental health conditions and vice versa to improve overall heart health.”

Kwapong says this new study only provides a snapshot of cardiovascular health among young people with depression, and that new studies need to look at how depression affects cardiovascular health over time.

No conflicts of interest were reported by the authors relating to this study. Partial funding for this study came from the American Heart Association.

Source: Johns Hopkins University

A new tool for noninvasive imaging can help illuminate hard-to-access structures and processes in the brain.

The small-molecule dye, or fluorophore, is the first of its kind that can cross the blood-brain barrier. What’s more, it allowed the researchers to differentiate between healthy brain tissue and a glioblastoma tumor in mice.

“This could be very useful for imaging-guided surgery, for example,” says Han Xiao, assistant professor of chemistry, biosciences, and bioengineering at Rice University. “Using this dye, a doctor could determine where the boundary is between normal brain tissue versus tumor tissue.”

If you’ve been to an aquarium or a nightclub, you’ve probably noticed the colorful glow that some objects or surfaces emit under a black light. Known as fluorescence, this glowing effect can be useful for rendering visible things that otherwise go unnoticed.

“Fluorescence imaging has been applied for imaging cancer in different parts of our body,” Xiao says. “The advantages of a fluorescence probe include high resolution and the ability to adapt the probe to read for different substances or activities.”

The deeper a tissue or organ is, the longer the wavelengths needed to discern the presence of fluorescent small molecules. For this reason, the second near-infrared (NIR-II) channel with wavelengths of 1,000 to 1,700 nanometers is especially important for deep-tissue imaging. For reference, visible light wavelengths range from 380 to 700 nanometers.

“Our tool is really valuable for deep imaging because it functions in the NIR-II region,” Xiao says. “In contrast to NIR-II wavelengths, fluorescent effects within the visible spectrum or with near-infrared wavelengths between 600 and 900 nanometers (NIR-I) will only get you skin-deep.”

Brain imaging poses a particular challenge not only because of tissue depth and accessibility, but also because of the blood-brain barrier, a layer of cells that acts as a very selective filter to restrict the passage of substances from the circulatory system to the central nervous system.

“People always want to know what exactly is happening in the brain, but it’s very hard to design a molecule that can penetrate the blood-brain barrier. Up to 98% of small-molecule drugs approved by the Food and Drug Administration (FDA) cannot,” Xiao says.

“Generally speaking, the reason a NIR-II dye molecule tends to be big is because it is a conjugated structure with many double bonds,” he continues. “This is a true problem and the reason why we have been unable to use fluorescence in brain imaging until now. We tried to address this issue by developing this new dye scaffold that is very small but has a long emission wavelength.”

Unlike the other two known NIR-II dye scaffolds, which are not capable of crossing the blood-brain barrier, the one Xiao and Zhen Cheng of Stanford University developed is more compact, which makes it a great candidate for probes or drugs targeting the brain. “In the future, we could modify this scaffold and use it to look for a lot of different metabolites in the brain,” Xiao says.

Beyond the brain, the dye has much greater lasting power than indocyanine green, the only NIR small-molecule dye approved by the FDA for use as a contrast agent. A longer lifespan means researchers have more time to record the fluorescent trace before it disappears.

“When exposed to light, the indocyanine green dye trace deteriorates in seconds, whereas our dye leaves a stable trace for more than 10 minutes,” Xiao says.

The study appears in the Journal of the American Chemical Society.

Support was provided by the Cancer Prevention Research Institute of Texas, the National Institutes for Health, the Department of Defense, the Robert A. Welch Foundation, the National Science Foundation, a Hamill Innovation Award, the John S. Dunn Foundation Collaborative Award, and the Stanford University Department of Radiology.

Source: Rice University

Toward the end of her life, the Austrian-born Jewish scientist Rudolphina Menzel acknowledged a horrifying reality: the dog-training techniques she pioneered had been used by the Nazis to commit atrocities.

“I suffered a lot knowing that my students in Austria and Germany were using the knowledge they acquired from me to use dogs to exterminate my people and other peoples,” she said in an interview roughly 10 years before her death in 1973.

“She had to constantly negotiate a shifting kaleidoscope of political, scientific, and cultural considerations…”

But in one of the more remarkable ironies of 20th-century history, Menzel also trained the dogs that helped create the state of Israel. She was a trailblazing Zionist pioneer.

A new book, Canine Pioneer: The Extraordinary Life of Rudolphina Menzel (Brandeis Press, 2023), chronicles Menzel’s life and career, exploring her seminal role in the development of cynology (the scientific study of the domestic dog) and modern Jewish, European, and Middle Eastern history.

Edited by the anthropologist Susan M. Kahn, the book details Menzel’s role in training the dogs used by the German military and police in the 1920s and early 1930s—and how she helped the fledgling Zionist state secure its independence from Britain and win the 1948 Arab-Israeli War.

“Rudolphina’s long, complicated, and eventful life was peppered with triumphs, marred by tragedies, and suffused with ideological tensions,” Kahn writes. “She had to constantly negotiate a shifting kaleidoscope of political, scientific, and cultural considerations in order to realize her extraordinarily ambitious scientific goals and activist objectives.”

Zionist and scientist

Menzel was born in 1891 to an upper-middle-class, assimilated Jewish Viennese family.

During childhood, she chanced on a discarded copy of the Zionist newspaper Die Welt and developed what became a lifelong commitment to the cause. By the time she earned her doctorate in chemistry from the University of Vienna in 1914, she was also an ardent socialist.

After she and her husband Rudolph settled in the northern Austrian city of Linz following World War I, Menzel met Austrian veterinarian and renowned dog breeder Joseph Bodingbauer. He gave the Menzels their first dog, a robust, brindle-colored boxer she named Mowgli.

Kahn details how and why Menzel transformed her love of dogs into a serious professional undertaking that enabled her to investigate scientific questions and solve societal problems.

She quickly mastered the burgeoning scientific field of cynology and designed an original, 16-year research study where she observed and recorded the daily behaviors of hundreds of boxers, taking note of which behavioral traits were genetic and how the environment shaped their temperament.

She also became fascinated with the dimensions of canine perception, particularly olfaction. In a landmark 1930 paper, she demonstrated that with the right training, dogs could discern the individual scents of particular human beings. She then trained her dogs to recognize a person’s smell at different times and under different conditions, making them ideal for tracking criminals and suspects.

Rise of the Nazis

Inevitably, Menzel’s work drew the interest of the German and Austrian police and military. She worked as a sought-after consultant and lectured to both groups on her techniques for breeding and training dogs that were obedient, intelligent, and skilled at police work.

It was standard practice to train police dogs in a foreign language so criminals or prisoners could not communicate with them. Menzel, whose Zionism inspired her to learn Hebrew, trained her dogs to obey commands in the language.

In 1934, a year after Hitler came to power, Menzel stopped working for Austria and Germany. But her dogs and training methods remained used by authorities well after the Nazis rose to power. It’s likely that some of the hounds deployed by the Nazis were, at least originally, trained to obey commands in Hebrew.

After the Nazis annexed Austria in 1938, local authorities in Menzel’s hometown ordered the “immediate removal of the Jewish kennel” on her property. In August of that year, she and her husband fled to Palestine with forged papers, taking only two of their hundreds of boxers.

Menzel in Palestine

Many early Zionist settlers were socialists and considered having pets a bourgeois habit out of keeping with the pioneering ethos. In addition, Jews in general had long had an ambivalent relationship with the canine species. The Hebrew Bible and the rabbinical commentaries in the Talmud depict dogs as unclean. In Eastern Europe, “du bist a hunt mit di oyern”—”you are a dog with ears” in Yiddish—was considered one of the worst insults.

Menzel changed all this by persuading Zionists that dogs could be much more than pets. They could be workers that protected Jewish lives and property. “Help us reclaim the dog for our people,” she wrote to her fellow Jews in Palestine in 1943. “Make room for a new pioneering path to reclaim the dog for the building of our country.”

Many of the dogs in Palestine were feral and free-roaming. Menzel, who coined the term Canaan dogs to describe them, bred and trained them. She discovered that some of these so-called “pariah dogs” could be loyal, intelligent, resourceful, and forgiving.

During World War II, Menzel worked with the British, equipping them with dogs to detect the mines the Germans laid in North Africa. But she made them promise never to use the animals against the Jews in Palestine, still under British control.

Menzel’s dogs were also used to detect intruders and patrol Jewish land, protecting against the Palestinians fighting Zionist settlers. When the 1948 war broke out against the surrounding Arab nations, her dogs were deployed by the Haganah, the main Zionist military organization. They transported messages by following scent trails laid between command centers and soldiers in the field. They also carried medical supplies and ammunition in saddles on their backs.

Columns of military dogs marched through the streets of Haifa and Tel Aviv in the 1949 victory parades.

Dogs “were tools that built the country no less than the plow, the tractor, the gun, and the water tower,” Menzel later wrote.

A change of focus

In the early 1950s, Menzel radically shifted the focus of her work and began training seeing-eye dogs. She founded the Israel Institute for Orientation and Mobility of the Blind, the first guide-dog institute in the Middle East and undertook extensive studies of the mobility needs of people with visual disabilities in Israel.

Menzel’s death went largely unnoticed, and her contributions to cynology were all but forgotten. This may be because of sexism or because most of her scientific work was never translated into English and failed to find a broader audience.

Kahn sees her book as an important first step to lifting Rudolphina Menzel out of obscurity.

Source: Brandeis University

A combination of silver nanoparticles and antibiotics may offer a way to fight against antibiotic-resistant bacteria, a new study shows.

Researchers hope to turn the discovery into viable treatment for some types of antibiotic-resistant infections that kill more than a million people globally each year.

“When I first saw the result, my first thoughts were, ‘Wow, this works!’”

For centuries, silver has been known to have antimicrobial properties. However, silver nanoparticles—microscopic spheres of silver small enough to operate at the cellular level—represent a new frontier in using the precious metal to fight bacteria.

In the new study, published in Frontiers in Microbiology, the researchers tested whether commercially available silver nanoparticles boost the power of antibiotics and enable these drugs to counter the very bacteria that have evolved to withstand them.

“We found that the silver nanoparticles and a common class of broad-spectrum antibiotics called aminoglycosides work together synergistically,” says senior author Daniel Czyz, an assistant professor in the microbiology and cell science department at the University of Florida/Institute of Food and Agricultural Sciences (UF/IFAS).

“When combined with a small amount of silver nanoparticles, the amount of antibiotic needed to inhibit the bacteria decreased 22-fold, which tells us that the nanoparticles make the drug much more potent,” Czyz explains. “In addition, aminoglycosides can have negative side effects, so using silver nanoparticles could allow for a lower dose of antibiotic, reducing those side effects.”

The findings were both surprising and exciting, says first author Autumn Dove, a doctoral candidate studying microbiology and cell science in the UF/IFAS College of Agricultural and Life Sciences. “When I first saw the result, my first thoughts were, ‘Wow, this works!’” she says.

Over the last several decades, overuse of antibiotics had led to the emergence of antibiotic-resistant bacteria and a decline in the effectiveness of traditional antibiotic drugs, the researchers say. The study’s findings indicate that silver nanoparticles have the potential to renew the effectiveness of some of these drugs.

“Let’s say you get a bad burn on your hand, and it gets infected with one of these resistant strains of bacteria,” Dove says. “It’s possible that dressing that burn with a combination of silver nanoparticles and antibiotics could both clear that infection and prevent those resistant bacteria from spreading elsewhere.”

Though antibiotics mainly target bacteria, they can also damage human and animal cells. Using a microscopic worm called C. elegans, the researchers confirmed that the silver nanoparticles did not also make the antibiotic more toxic to non-bacterial cells.

Building off the study’s promising findings, the scientists next plan to seek FDA authorization for clinical trials and work with UF Innovate to patent an antimicrobial product that uses silver nanoparticles.

The silver nanoparticles used in the study were manufactured by the Natural Immunogenics Corporation, which helped fund the study through the UF Industry Partnerships Matching Grant Program.

Source: University of Florida