Tuesday, May 23, 2023

New method reveals bacterial reaction to antibiotics in five minutes


Peer-Reviewed Publication

KAROLINSKA INSTITUTET

“We are confident and hope that this can be one of many tools that doctors need to tackle antibiotic resistance, which is a serious and growing problem,” says principal investigator Vicent Pelechano, associate professor at the Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet.

The method is called 5PSeq, is simple to use, and is based on sequencing the messenger RNA (mRNA) that the bacteria break down as they synthesise proteins. The measurements reveal how the bacteria are affected by different environmental factors, such as antibiotic treatments and other types of stress.

Rapid test for clinical use

The researchers tested the method on a total of 96 bacterial species from different phyla in complex clinical samples taken, for example, from faecal matter and the vagina, but also in compost samples. After only a matter of minutes, they were able to see whether or not the bacteria responded to antibiotic treatment; the effect was most salient after about half an hour.

3N Bio is a company that Dr Pelechano and some of his colleagues have started up in the KI Innovations incubator to develop the method and create a rapid molecular test for clinical use. They have now received financing from the Swedish Research Council to demonstrate proof of concept for such a test in collaboration with the Karolinska University Hospital.

“It’s crucial that doctors can quickly find the right antibiotics for seriously ill patients with bacterial infections to reduce the unnecessary use of antibiotics,” says Dr Pelechano. “Current methods of testing antibiotic resistance can take hours or even days, but often treatment needs to be given more promptly than that to avoid serious consequences for the patient. Because of this, a broad-spectrum antibiotic is often prescribed, which increases the risk of resistance.”

Examine how bacteria interact

Apart from measuring antibiotic resistance, the method can be used to help researchers understand how bacteria handle stress and interact with each other and with their hosts. The researchers will continue to study complex gut samples to examine how the bacterial communities interact in our gut and contribute to health and disease.

The research was financed by the Ragnar Söderbergs foundation (Swedish Foundations’ Starting Grant), the Swedish Research Council, the Knut and Alice Wallenberg Foundation (a Wallenberg Academy Fellowship), EU’s Horizon 2020, among others. See the scientific article for a complete list. 3N Bio was co-founded by Vicent Pelechano and the two first authors of the paper, Susanne Huch and Lilit Nersisyan.

Publication: “Atlas of mRNA translation and decay for bacteria”, Susanne Huch, Lilit Nersisyan, Maria Ropat, Donal Barrett, Mengjun Wu, Jing Wang, Valerie D Valeriano, Nelli Vardazaryan, Jaime Huerta-Cepas, Wu Wei, Juan Du, Lars M Steinmetz, Lars Engstrand, Vicent Pelechano. Nature Microbiology, online 22 May 2023, doi: 10.1038/s41564-023-01393-z.

Public aware of and accept use of bacteria-killing viruses as alternative to antibiotics, study shows























Peer-Reviewed Publication

UNIVERSITY OF EXETER

The public are in favour of the development of bacteria-killing viruses as an alternative to antibiotics – and more efforts to educate will make them significantly more likely to use the treatment, a new study shows.

The antimicrobial resistance (AMR) crisis means previously treatable infections can kill. This has revitalised the development of antibiotic alternatives, such as phage therapy, which was first explored over a century ago but abandoned in many countries in favour of antibiotics.

The study shows public acceptance of phage therapy is already moderately high, and priming people to think about novel medicines and antibiotic resistance significantly increases their likelihood of using it.

There is a higher acceptance of phage therapy when described without using perceived harsh words, such as “kill” and “virus” but instead “natural bacterial predator”.

Those who took part in the survey had a high awareness of antibiotic resistance – 92 per cent had heard of antibiotic resistance, but only 13 per cent reported that they had heard about phage therapy prior to the survey.

Success and side effect rate, treatment duration, and where the medicine has been approved for use, influenced their treatment preferences.

The study was conducted by Sophie McCammon, Kirils Makarovs, Susan Banducci and Vicki Gold from the University of Exeter.

Dr Banducci said: “While phage therapy remains poorly understood by the UK public our research suggests there is extensive acceptance and support for its development. Exposure to only very limited information about antibiotic resistance and alternative treatments to antibiotics greatly increases the public acceptance of phage therapy.”

Dr Gold said: “Those involved in the research wanted to know more about phage therapy and were inspired to research this topic after completing our survey. Exposure to only a very limited amount of information about phage therapy significantly increases acceptance.”

Researchers held a workshop with experts and a review of phage research. They also fielded a survey assessing the UK public’s acceptance, opinions and preferences regarding phage therapy. A total of 787 people completed the survey, distributed in December 2021.

One group was given two scenarios; in the first they presented with a minor infection, and in the second they presented with an infection that did not respond well to antibiotics for three months. In each scenario, the group ranked the selected attributes based on their importance in deciding whether to accept a treatment or not.

Participants were randomly assigned one of four descriptions of phage therapy and then surveyed to assess their acceptance of the treatment. The acceptance of phage therapy was high across the board. However, describing phage therapy using perceived harsh words, such as “kill and “virus”, resulted in lower acceptance rates than alternative descriptions. Additionally, participants who had recent exposure to information about antibiotic resistance and alternative treatments were more accepting of phage therapy.

From the 787 participants who completed the survey, 213 left written responses expressing their opinions on the potential of phage therapy. Of this group, 38 per cent showed a specific interest in phage therapy development, while a further 17 per cent supported the development of antibiotic alternatives generally.

Sophie McCammon said: “An advantage of phage therapy is often the minimal side effects. Emphasising this through education and marketing may increase public acceptance of phage therapy.

“Even though phage therapy may be some years away from routine clinical use in the UK, increasing pressures from the AMR crisis require evaluation of the UK public’s acceptance of alternative treatments.

“The public desire for increased education is apparent. Expanding schemes which are interactively involving children in phage research not only generates excitement for the therapy now, but also promotes awareness in the generation likely to be treated with antibiotic alternatives.”

How a drought affects trees depends on what’s been holding them back

In cold, harsh environments, drought can actually benefit the trees by extending the growing season

Peer-Reviewed Publication

UNIVERSITY OF CALIFORNIA - SANTA BARBARA

Whitebark Pines 

IMAGE: WHITEBARK PINES GROWING IN COLD, HIGH ELEVATION REGIONS GREW MORE DURING DROUGHTS, WHICH LENGTHENED THEIR GROWING SEASON. view more 

CREDIT: JOAN DUDNEY

(Santa Barbara, Calif.) — Droughts can be good for trees. Certain trees, that is.

Contrary to expectation, sometimes a record-breaking drought can increase tree growth. Why and where this happens is the subject of a new paper in Global Change Biology.

A team of scientists led by Joan Dudney at UC Santa Barbara examined the drought response of endangered whitebark pine over the past century. They found that in cold, harsh environments — often at high altitudes and latitudes — drought can actually benefit the trees by extending the growing season. This research provides insights into where the threats from extreme drought will be greatest, and how different species and ecosystems will respond to climate change.

Many factors can constrain tree growth, including temperature, sunlight and the availability of water and nutrients. The threshold between energy-limited and water-limited systems turns out to be particularly significant. Trees that try to grow in excessively cold temperatures — often energy-limited systems — can freeze to death. On the other hand, too little water can also kill a tree, particularly in water-limited systems. Over time, many tree species have adapted to these extreme conditions, and their responses are broadly similar. They often reduce growth-related activities, including photosynthesis and nutrient uptake, to protect themselves until the weather improves.

“Interestingly, the transition from energy- to water-limited growth can produce highly unexpected responses,” explained Dudney, an assistant professor in the Bren School of Environmental Science & Management and the Environmental Studies Program. “In cold, energy-limited environments, extreme drought can actually increase growth and productivity, even in California.”

Dudney and her colleagues extracted 800 tree cores from whitebark pine across the Sierra Nevada, comparing the tree rings to historical records of climate conditions. This climate data spanned 1900 to 2018, and included three extreme droughts: 1959–61, 1976–77, and 2012–15. They recorded where tree growth and temperature showed a positive relationship, and where the relationship was negative.

The authors found a pronounced shift in growth during times of drought when the average maximum temperature was roughly 8.4° Celsius (47.1° Fahrenheit) between October and May. Above this threshold, extreme drought reduced growth and photosynthesis. Below this temperature, trees grew more in response to drought.

“It’s basically, ‘how long is the growing season?’” Dudney said. Colder winters and higher snowpack often lead to shorter growing seasons that constrain tree growth. Even during an extreme drought, many of the trees growing in these extreme environments did not experience high water stress. This surprised the team of scientists, many of whom had observed and measured the unprecedented tree mortality that occurred at slightly lower elevations in the Sierra Nevada.

Dudney was curious whether drought impacts growth in just the main trunk, or the whole tree. Without more data, the trends they saw could be a result of disparate processes all responding to the drought differently, she explained. Fortunately, whitebark pine retains its needles for roughly eight years. This provided additional data that could address this question.

The researchers shifted their attention from dendrology to chemistry. Atoms of the same element can have different weights, or isotopes, thanks to the number of neutrons they contain. Several aspects of a plant’s metabolism can influence the relative abundance of heavy, carbon-13 and light, carbon-12 in tissues such as their leaves and needles. These changes provide a rough guide to the amount of water stress a tree experienced during drought. This was a boon for the researchers, because isotopic data from the pine needles spanned drought and non-drought years.

Analyzing needle growth, carbon and nitrogen isotopes revealed that the whole tree was affected by the threshold between water-limited and energy-limited systems. Trunk growth, needle growth, photosynthesis and nutrient cycling responded in opposite directions to drought above and below the threshold between energy- and water-limited systems.

The future of whitebark pine is highly uncertain. The species — recently listed as threatened under the Endangered Species Act — faces many threats, including disease, pine beetle infestation and impacts from altered fire regimes. It’s clear from this research that drought and warming will likely exacerbate these threats in water-limited regions, but warming may be beneficial for growth in energy-limited environments. “This research can help develop more targeted conservation strategies,” said Dudney, “to help restore this historically widespread tree species.” Indeed, the pine’s range encompasses a diverse region, stretching from California to British Columbia, and east to Wyoming.

The findings also have implications more broadly. Approximately 21% of forests are considered energy limited, and an even higher percentage can be classified as water limited. So transitions between these two climatic regimes likely occur around the globe. What’s more, the transition seems to have an effect on nitrogen cycling. Trees in water-limited environments appeared to rely less on symbiotic fungi for nitrogen, which is critical for tree growth in harsh, energy-limited environments.

“Droughts are leading to widespread tree mortality across the globe,” Dudney said, “which can accelerate global warming.” 

Deciphering the many ways trees respond to drought will help us better predict where ecosystems are vulnerable to climate change and how to develop more targeted strategies to protect our forests.

Allowing financial trading in California’s wholesale electricity market significantly reduced volatility of prices, electricity production costs, carbon emissions

Peer-Reviewed Publication

CARNEGIE MELLON UNIVERSITY

Forward markets—over-the-counter marketplaces that set the price of a financial instrument or asset—are used to trade a variety of instruments, including securities and commodities. In a new study, researchers measured the extent to which forward prices and spot prices (the current market price at which a given asset can be bought or sold for immediate delivery) agreed in markets with transaction costs in California, studying time periods before and after the state introduced financial trading to its wholesale electricity market in 2011.

The study found that allowing trading in this market led to a reduction in the implicit cost of trading day-ahead/real-time price differences, the volatility of these price differences, and the volatility of real-time prices. In addition, operating costs and fuel use fell on days after the introduction of purely financial participation.

The study, by researchers at Carnegie Mellon University (CMU) and Stanford University, is published in American Economic Journal: Economic Policy.

“Our results have important implications for the design of wholesale electricity markets with large shares of intermittent renewable resources,” says Akshaya Jha, assistant professor of economics and public policy at CMU’s Heinz College, who led the study.

Forward markets are believed to aggregate information about future spot prices and reduce the cost of producing the commodity. But it has been difficult to link increases in forward market liquidity to reductions in production costs due to the long time period over which most commodities are produced and traded. To examine changes in forward-spot price convergence after the implementation of financial trading, researchers measured the 24-dimensional vector of hourly average day-ahead prices at a location in the transmission network versus the 24-dimensional vector of hourly average real-time prices at the same location.

Using this model, they computed two measures of implied transaction costs using hourly, location-specific data on day-ahead and real-time prices from April 1, 2009, to November 30, 2012, before and after financial trading began at most pricing locations in California. The California Independent System Operator introduced financial participation on February 1, 2011, to reduce differences between day-ahead and real-time prices at more than 4,000 locations in the state’s transmission network.

The study found that both measures fell substantially after California introduced purely financial participation. In addition, both measures fell more at locations where trading was restricted prior to the introduction of financial trading. This suggests that allowing financial trading resulted in day-ahead prices that better reflect real-time conditions.

The study’s findings also suggest that physical market outcomes improved as a consequence of the better information encapsulated in day-ahead prices after financial trading. Namely, they show that residualized fuel cost per megawatt hour (MWh) of gas-fired output and input fuel use per MWh of gas-fired output fell after financial trading was introduced on days when the complexity of the real-time market-clearing problem was high but not on days when complexity was low–again, indicative of the importance of improved day-ahead information. The results remained similar regardless of whether complexity was measured using daily total demand, the daily standard deviation across locations and hours in real-time prices, or the total number of daily starts. The study’s authors estimated that fuel costs per MWh fell 2% after the introduction of financial trading on high-demand days relative to low-demand days. This would result in an average $16.6 million reduction in annual total fuel costs.

As the share of electricity demand in a region grows, system operators are often required to impose more operating constraints on day-ahead and real-time markets to maintain the balance between supply and demand throughout the day. Controllable generation resources with positive startup costs are also likely to fluctuate more frequently because intermittent renewables can start and stop producing with very little notice. Rising transmission network constraints are also likely to bind as the percentage of electricity production from wind and solar resources distributed across the grid increases.

“The location-specific bids and offers submitted by purely financial participants can reduce day-ahead/real-time price differences caused by uncertainty in intermittent renewable output,” explains Frank Wolak, professor of economics at Stanford University, who coauthored the study. “These financial bids and offers can also ensure that the least-cost combination of controllable resources is available to compensate for fluctuations in real-time output from intermittent renewables on high-complexity days.”

THERE IS ONLY THE WORKING CLASS

How intermittent feedback drives consumer impatience

THERE IS NO CONSUMER CLASS

News from the Journal of Consumer Psychology

Peer-Reviewed Publication

SOCIETY FOR CONSUMER PSYCHOLOGY

Researchers from Fudan University’s School of Management published a new paper in the Journal of Consumer Psychology that provides original insights about the impact different types of feedback consumers have on consumers’ psychological state.

Specifically, the research examines “piecemeal” feedback informing consumers of their progress or performance during each step of an online process such as making a purchase, playing a computer game, or customizing a product. The work compares intermittent feedback with “lump sum” feedback offered at the end of a process.

The article, recently published in the Journal of Consumer Psychology, is authored by Haichao Lin, Qian Xu, and Liyin Jin and offers a deeper understanding of how external factors impact consumers’ internal experience. Previous research has focused on how feedback reinforces consumer behavior but not on how different types of feedback affect consumers’ mindset and subsequent actions.

The authors found that intermittent feedback helped consumers connect their actions to progress toward a goal. This association generated a sense of impatience compared to those who only received lump sum feedback at the completion of a goal.  For example, piecemeal feedback such as “You have completed Step 1 in this customization, please proceed to Step 2…” provides consumers with the satisfaction of accomplishing an action. This reward boosts their motivation to quickly complete the next, generating greater impatience.

Through a series of five studies, the research team found that regular feedback forms a strong, reliable action-outcome association, spurring consumers to pursue prompt results in subsequent related or unrelated situations.

“This effect is robust regardless of whether the valence of feedback is positive or negative, whether the outcome involves gain or loss, and whether the form of feedback is monetary or informative,” the authors found.

The timing of piecemeal feedback is significant. The researchers discovered that piecemeal feedback increases consumer impatience only when it is provided at a fixed pace (rather than at a varied schedule) and immediately following specific behaviors that are directed toward action (rather than inaction).

The researchers propose several avenues for future research related to their findings including whether the effect of piecemeal feedback on consumer impatience holds if consumers are told beforehand about the feedback procedure. Given that the team measured consumer impatience immediately after receiving feedback, they suggest future studies could delay such measurement to explore how long the activated action–outcome persists.

Full article and author contact information available at https://myscp.onlinelibrary.wiley.com/doi/10.1002/jcpy.1347

#####

About the Journal of Consumer Psychology

The Journal of Consumer Psychology publishes top-quality research articles that contribute both theoretically and empirically to our understanding of the psychology of consumer behavior. The Journal is intended for researchers in consumer psychology, social and cognitive psychology, judgment and decision making, and related disciplines. It is also relevant to professionals in advertising and public relations, marketing and branding, consumer and market research, and public policy. Published by the Society for Consumer Psychology since its founding in 1992, JCP has played a significant role in shaping the content and boundaries of the consumer psychology discipline. Dr. Lauren Block (Lippert Professor of Marketing at the Zicklin School of Business, Baruch College) serves as the current Editor-in-Chief.

About the Society for Consumer Psychology (SCP)

The Society for Consumer Psychology is the premier voice to further the advancement of the discipline of consumer psychology in a global society. Building upon the Society's excellence in mentoring young behavioral scientists, the SCP facilitates the generation and dissemination of intellectual contributions and promotes professional development and research opportunities for its members around the globe. Dr. Tiffany White, Associate Professor of Business Administration and Bruce and Anne Strohm Faculty Fellow at Gies College of Business, University of Illinois Urbana-Champaign, currently serves as the President.