How Tubular Bacterial Weapons Compromise Plant Cells to Cause Disease

An apple tree infected with fire blight reveals leaves that appear as if they were burned. HHMI Investigator Sheng Yang He and a team of researchers identified a plug-like molecule that could lead to new techniques to fight fire blight and other plant diseases.
Photo Credit: Sebastian Stabinger
(CC BY-SA 3.0.)

Some bacteria attack crops by delivering proteins that puncture the plant’s cell membranes, according to new research that explains the long-sought mechanism by which pathogens can release water within plant tissues, causing devastating infections.

In experiments first described in a preprint on bioRxiv and later published in Nature, a team led by plant microbiologist Sheng Yang He went a step further and found a way to block the holes the microbes make. Their research identified a plug-like molecule that showed potential for controlling diseases including fire blight, which can kill off apple and pear trees, leaving orchards looking as if they were burned.

“For 25 years, my lab and others have been trying to understand exactly how these bacterial proteins manipulate water within leaves,” says He, a Howard Hughes Medical Investigator at Duke University. “Now we have an answer: They open up channels through which water can move, disrupting plants’ internal water balance.”

Researchers have searched for this kind of detailed insight in hopes of opening the door to improved ways for fighting plant disease. Usually making such a connection can take years, if it is possible at all. However, He and his colleagues capitalized on this discovery quickly — using the dimensions of the pores to identify molecules perfectly sized for blocking them and protecting plants.

New dog, old tricks: New AI approach yields ‘athletically intelligent’ robotic dog

A doglike robot can navigate unknown obstacles using a simple algorithm that encourages forward progress with minimal effort.

Video Credit: Shanghai Qi Zhi Institute/Stanford University

With a simplified machine learning technique, AI researchers created a real-world “robodog” able to leap, climb, crawl, and squeeze past physical barriers as never before.

Someday, when quakes, fires, and floods strike, the first responders might be packs of robotic rescue dogs rushing in to help stranded souls. These battery-powered quadrupeds would use computer vision to size up obstacles and employ doglike agility skills to get past them.

Toward that noble goal, AI researchers at Stanford University and Shanghai Qi Zhi Institute say they have developed a new vision-based algorithm that helps robodogs scale high objects, leap across gaps, crawl under thresholds, and squeeze through crevices – and then bolt to the next challenge. The algorithm represents the brains of the robodog.

“The autonomy and range of complex skills that our quadruped robot learned is quite impressive,” said Chelsea Finn, assistant professor of computer science and senior author of a new peer-reviewed paper announcing the teams’ approach to the world, which will be presented at the upcoming Conference on Robot Learning. “And we have created it using low-cost, off-the-shelf robots – actually, two different off-the-shelf robots.”

Insect Cyborgs: Towards Precision Movement

Image Credit: ©Dai Owaki

Insect cyborgs may sound like science fiction, but it's a relatively new phenomenon based on using electrical stimuli to control the movement of insects. These hybrid insect computer robots, as they are scientifically called, herald the future of small, high mobile and efficient devices.

Despite significant progress being made, however, further advances are complicated by the vast differences between different insects' nervous and muscle systems.

In a recent study published in the journal eLife, an international research group has studied the relationship between electrical stimulation in stick insects' leg muscles and the resultant torque (the twisting force that makes the leg move).

Predictions of the effect of drugs on individual cells are now possible

How differently do various cancer cells respond to the effects of drugs? A new method from Zurich researchers now makes it possible to accurately predict the effect on individual cells.
Photo Credit: National Cancer Institute

Experts from ETH Zurich, the University of Zurich, and University Hospital Zurich have used machine learning to jointly create a innovative method. This new approach can predict how individual cells react to specific treatments, offering hope for more accurate diagnoses and therapeutics.

Cancer is triggered by changes in cells that lead to the proliferation of pathogenic tumor cells. In order to find the most effective combination and dosage of drugs, it is advantageous if physicians can see inside the body, so to speak, and determine what effect the drugs will have on individual cells.

An interdisciplinary research team of biomedical and computer scientists from ETH Zurich, the University of Zurich, and the University Hospital Zurich has now developed a machine learning approach that allows such cell changes and drug effects to be modelled and predicted with much greater accuracy and nuance than before.

Growth of coral reefs likely cannot keep pace with rising sea level

The upper panel shows a coral reef margin in Belize with living branched Acropora (elkhorn) and platy Millepora (fire) corals, which are both competitive and fast-growing. The lower panel shows broken branches of dead Acropora corals overgrown by weedy, fertile hill and finger corals (Porites) as well as fleshy algae.
Photo Credit: E. Gischler.

In identifying and dating coral remains in drill cores taken from Belize reefs, a team of experts from Goethe University Frankfurt and partners from Germany, the USA and Canada has shown the importance of specific types of coral for reef-building during the current Holocene geological epoch, dating back some 12,000 years. The scientists found that certain coral species disappeared for longer periods in the past due to climate changes, and identified another climate-related threat to coral reefs: In addition to warming and ocean acidification, among others, the rising sea level also threatens coral reefs, whose growth rates cannot keep up. 

Tropical coral reefs could end up being one of the first victims of climate change. The marine diversity hotspots are threatened by and declining as a result of global warming, ocean acidification, a deterioration of water quality, as well as diseases of reef-building organisms, and their growth is unable to keep up with the projected rise in sea levels. These are some of the conclusions drawn by an interdisciplinary team of scientists from Goethe University Frankfurt's Institute of Geosciences, the company ReefTech Inc., the GEOMAR Helmholtz Center of Ocean Research, the University of Ottawa's Department of Earth and Environmental Sciences, and the GSI Helmholtz Center of Heavy Ion Research. Their findings are based on an examination of 22 drill cores collected from the Belize barrier reef and atolls, the largest reef system in the Atlantic Ocean, which focused on identifying and dating coral growth and accretion rates over the past 9,000 years. 

Optimizing Continuous-Variable Functions with Quantum Annealing

Quantum annealing (QA) can be competitive to classical algorithms in optimizing continuous-variable functions when running on appropriate hardware, show researchers from Tokyo Tech. By comparing the performance of QA running on a D-Wave quantum computer to that of state-of-the-art classical algorithms, they find that a sufficient suppression of thermal noise can enable QA to significantly outperform classical algorithms.

Quantum annealing (QA) is a cutting-edge algorithm that leverages the unique properties of quantum computing to tackle complex combinatorial optimization problems (a class of mathematical problems dealing with discrete-variable functions). Quantum computers use the rules of quantum physics to solve such problems potentially faster than classical computers. In essence, they can explore multiple solutions to a problem simultaneously, giving them a significant speed advantage for certain tasks over classical computers. In particular, QA harnesses the phenomenon of "quantum tunneling," where particles can "tunnel" through energy barriers without the requisite energy to cross over them, to find solutions for combinatorial optimization problems.

Up until now, QA has almost exclusively been used to solve discrete-variable functions (functions that have discrete-valued variables). The potential of QA for optimizing continuous-variable functions has remained largely unexplored.

Wastewater detects signs of antimicrobial resistance in aged care

Photo Credit: Jsme MILA

A new study published today, analyzing wastewater samples from several aged care and retirement homes in Adelaide, has uncovered worrying signs of antimicrobial resistance (AMR) in at least one facility.

High levels of bacterial resistance against three common antibiotics – ceftazidime, cefepime and ciprofloxacin – were identified in one aged care residential home. A second facility recorded above average levels of antimicrobial resistance to gentamicin, putting residents’ health at risk.

The listed antibiotics are used to treat a variety of bacterial infections, including pneumonia, gynecological, urinary and respiratory tract infections, and those affecting bones and joints.

University of South Australia microbiologist, Associate Professor Rietie Venter, who led the study, says AMR is a concerning trend in aged care facilities.

“Antimicrobial resistance is projected to lead to 300 million deaths worldwide by 2060, and aged care residents are among the most vulnerable due to frequent, inappropriate use of medicines,” Assoc Prof Venter says.

Study raises concerns over powdered infant formula preparation machines

Photo Credit: Lucy Wolski

A study by Swansea University academics into powdered infant formula preparation safety has revealed that 85% of the 74 infant formula preparation machines tested by parents in UK homes did not appear to produce water that would be hot enough to kill all harmful bacteria in infant formula, and this could pose a serious risk to infant health.

This was compared to 69 parents in the study who used a kettle to heat the water used to prepare infant formula, where 22% reported water temperatures that were not hot enough to kill all harmful bacteria.

Almost three quarters of infants in the UK are fed infant formula in the first six weeks of life and this rises to 88% by six months of age. 

Formula-fed infants have a higher risk of gastrointestinal infections compared to breastfed infants1 which can be attributed, in part, to bacterial contamination from: the powdered infant formula itself (which cannot be made sterile), the equipment used for feeding, and also preparing infant formula with unclean hands. To help reduce the risk of such infections, the NHS has adopted the World Health Organization (WHO) recommendation that water used to make infant formula should be boiled and cooled, so that it is at a temperature of at least 70oC to eliminate bacteria.

Potential genetic screening for aggressive melanoma

Photo Credit: cottonbro studio

Researchers from The University of Queensland and The Alfred hospital in Melbourne have identified gene variants which may contribute to people being at higher risk for nodular melanoma.

Dr Mitchell Stark from UQ’s Frazer Institute said nodular melanoma only accounts for around 14 per cent of invasive melanoma cases, but the aggressive subtype is the largest contributor to melanoma deaths.

“Melanoma is highly curable by surgery when diagnosed early, but nodular melanoma is often detected later because of its rapid growth rate and short window of opportunity for detection and diagnosis,” Dr Stark said.

“Up to 27 per cent of nodular melanoma cases appear as a skin-colored tumor, as opposed to other more pigmented melanomas, adding an additional challenge to early diagnosis.

“We hope that by identifying these rare variants, it could help establish screening programs to determine the people most at risk.”

Scientists illuminate the mechanics of solid-state batteries

The image conceptualizes the processing, structure and mechanical behavior of glassy ion conductors for solid state lithium batteries.
Illustration Credit: Adam Malin/ORNL, U.S. Dept. of Energy

As current courses through a battery, its materials erode over time. Mechanical influences such as stress and strain affect this trajectory, although their impacts on battery efficacy and longevity are not fully understood.

A team led by researchers at the Department of Energy’s Oak Ridge National Laboratory developed a framework for designing solid-state batteries, or SSBs, with mechanics in mind. Their paper, published in Science, reviewed how these factors change SSBs during their cycling.

“Our goal is to highlight the importance of mechanics in battery performance,” said Sergiy Kalnaus, a scientist in ORNL’s Multiphysics Modeling and Flows group. “A lot of studies have focused on chemical or electric properties but have neglected to show the underlying mechanics.”

The team spans several ORNL research areas including computation, chemistry and materials science. Together, their review painted a more cohesive picture of the conditions that affect SSBs by using perspectives from across the scientific spectrum. “We’re trying to bridge the divide between disciplines,” said Kalnaus.