Achilles’ heel of dangerous hospital pathogen

A scanning electron micrograph (SEM) of a highly magnified cluster of Gram-negative, non-motile en:Acinetobacter baumannii bacteria; Mag - 13331x. 
Credit: Janice Carr

A team from Research Unit 2251 of the German Research Foundation led by Goethe University has shed light on the structure of an enzyme important in the metabolism of the pathogenic bacterium Acinetobacter baumannii. The enzyme “MtlD" is critical for the bacterium's synthesis of the sugar alcohol mannitol, with which it protects itself against water loss and desiccation in dry or salty environments such as blood or urine. Structural analysis has revealed weak spots where it might be possible to inhibit the enzyme and thus attack the pathogen.

Each year, over 670,000 people in Europe fall ill through pathogenic bacteria that are resistant to antibiotics, and 33,000 die of the diseases they cause. In 2017, the WHO named antibiotic resistance as one of the greatest threats to health worldwide. Especially feared are pathogens that are resistant to several antibiotics. Among them, Acinetobacter baumannii stands out, a bacterium with an extraordinarily pronounced ability to develop multi-resistance and, as a “hospital superbug", dangerous above all for immunosuppressed patients. Acinetobacter baumannii is highly resilient because it can remain infectious for a long time even in a dry environment and thus endure on the keyboards of medical devices or on ward telephones and lamps. This property also helps the microbe to survive on dry human skin or in body fluids such as blood and urine, which contain relatively high concentrations of salts and other solutes.

Finding Planets That Have No Star

 

Most planets orbit a star, but some planets can escape and “go rogue.” But how do astronomers study planets that wander the cold dark of interstellar space?

Join our host, Summer Ash of the National Radio Astronomy Observatory, as she talks about how radio astronomers' study rogue planets.

Source/Credit: National Radio Astronomy Observatory / Amy C. Oliver

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Parasites thrive if hosts survive

The Australian native social parasitic bee Inquilina and its host Exoneura
Credit: Flinders University

Like diseases affecting humans, parasites can wage a deadly evolutionary ‘arms race’ against their hosts. But can hosts and parasites upgrade their weapons at the same rate?

The parasite bee and host species have evolved in complementary ways.

This can be a very unequal battle for two reasons, Flinders University researchers say. If the parasite is too successful it will wipe out its host, and therefore lose its only means of surviving.

At the same time, evolutionary ‘wars’ between hosts and their parasites depend on their rates of evolution; we can think of that as their ability to ‘upgrade their weapons’, says Associate Professor Mike Schwarz, from the College of Science and Engineering.

The Flinders University study examined this conundrum by examining a native Australian social bee (Exoneura) and its social parasite, another bee (Inquilina).

“These parasitic species spend their entire life cycle within the nest of the host species and have extreme adaptations to social parasitism, they are not able to survive without their hosts,” says first author Dr Nahid Shokri-Bousjein in an article in Ecology and Evolution.

The ability of species to adapt to existential challenges depends on their ability to ‘discover’ new strategies via random mutations.

Squid recorded color-matching substrate for the first time

A species of oval squid (locally known as Shiro-ika) from Okinawa is being cultured at OIST’s Marine Science Station. This animal exhibited amazing camouflaging abilities never before recorded in squid. Credit: Ryuta Nakajima / OIST.

While octopus and cuttlefish are famous for their use of camouflage to match the color of the substrate, a third type of cephalopod—the squid—has never been reported displaying this ability. Now, in a study published in Scientific Reports, scientists from the Physics and Biology Unit at the Okinawa Institute of Science and Technology Graduate University (OIST) have shown that squid can and will camouflage to match a substrate as a way of avoiding predators. This work opens up research avenues on how squid see and perceive the world around them. Furthermore, it sheds light on their behavior, and thus could go on to inform conservation initiatives.

“Squid usually hover in the open ocean but we wanted to find out what happens when they move a bit closer to a coral reef or if they’re chased by a predator to the ocean floor,” explained one of the three first authors, Dr. Ryuta Nakajima, OIST visiting researcher. “If substrate is important for squid to avoid predation than that indicates that increases or decreases in squid populations are even more tied to the health of coral reef than we thought.”

Previous studies on cephalopod camouflage have mostly been conducted on cuttlefish and octopus. Squids, as an animal that tends to live in the open ocean, are notoriously hard to keep in captivity and so have been avoided for this kind of research. But, since 2017, the scientists in the OIST’s Physics and Biology Unit have been culturing a species of oval squid in captivity.

COVID-19 vaccine not associated with birth defects detectable on ultrasound

Dr. Emily Miller explains elements of a fetal ultrasound to fellow study author Dr. Rachel Ruderman. Credit: Northwestern University

The exclusion of pregnant patients in initial COVID-19 vaccine clinical trials left many patients and doctors wondering how the vaccine might affect pregnant patients and their unborn babies. But a new Northwestern Medicine study finds the vaccine is not associated with birth defects that are detectable on ultrasound.

“This is yet another important piece of data that helps bridge the chasm that was left when pregnant individuals were excluded from those initial vaccine trials,” said corresponding author Dr. Emily Miller, chief of obstetrics at Northwestern Medicine and assistant professor of maternal fetal medicine at Northwestern University Feinberg School of Medicine.

The study was published April 4 in the journal JAMA Pediatrics.

“One of the reasons women struggle with the vaccine in pregnancy is they’re worried about their babies and don’t want to take any risks,” said first author Dr. Rachel Ruderman, a fourth-year resident in obstetrics and gynecology at Feinberg. “This study shows there really is no increased risk of birth defects, and it supports other evidence that shows the vaccine is safe and beneficial for mom and baby.”

New perspective highlights promise of hybrid approach for cellulosic biofuel production

Scientists with the Center for Bioenergy Innovation at ORNL highlighted a hybrid approach that uses microbes and catalysis to convert cellulosic biomass into fuels suitable for aviation and other difficult-to-electrify sectors.
Credit: ORNL, U.S. Dept. of Energy

The rapid pace of global climate change has added urgency to developing technologies that reduce the carbon footprint of transportation technologies, especially in sectors that are difficult to electrify. In response, researchers collaborating through the Center for Bioenergy Innovation make the case that scientific advances support a hybrid approach using biological and catalytic methods for producing cellulosic biofuel for use in airplanes, ships and long-haul trucks.

As presented in Energy & Environmental Science, this hybrid approach uses microbes to convert cellulosic biomass such as wood and grass into an intermediate, small-molecule product such as ethanol. The ethanol would then be catalytically upgraded into hydrocarbon fuels suitable for heavier vehicles.

The study states that using the combination of biological and catalytic methods “is a promising approach to bridge the current gap between the fuel molecules that biology most readily makes and the fuel molecules that the world would most value producing from biomass.”

“We’re looking at this as taking the best of both worlds: Using biology for what it really does well, which is to make these small molecules, and then using catalysis to do what it does well, which is to make hydrocarbon fuel mixtures rapidly,” said Brian Davison, co-author and chief science officer for CBI, headquartered at the Department of Energy’s Oak Ridge National Laboratory.

The global “plastic flood” reaches the Arctic

Collecting plastics after the catamaran.
Credit: Alfred-Wegener-Institute / Esther Horvath

Even the High North can’t escape the global threat of plastic pollution. An international review study just released by the Alfred Wegener Institute shows the flood of plastic has reached all spheres of the Arctic: large quantities of plastic - transported by rivers, the air and shipping- can now be found in the Arctic Ocean. High concentrations of microplastic can be found in the water, on the seafloor, remote beaches, in rivers, and even in ice and snow. Plastic is not only a burden for ecosystems; it could also worsen climate change. The study was just released in the journal Nature Reviews Earth & Environment.

The numbers speak for themselves. Today, between 19 and 23 million metric tons of plastic litter per year end up in the waters of the world – that’s two truckloads per minute. Since plastic is also very stable, it accumulates in the oceans, where it gradually breaks down into ever smaller pieces – from macro- to micro- and nanoplastic and can even enter the human bloodstream. And the flood of debris is bound to get worse: global plastic production is expected to double by 2045.

The consequences are serious. Today, virtually all marine organisms investigated – from plankton to sperm whales – come into contact with plastic debris and microplastic. And this applies to all areas of the world’s oceans – from tropical beaches to the deepest oceanic trenches. As the study published by the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) now shows, the High North is no exception. “The Arctic is still assumed to be a largely untouched wilderness,” says AWI expert Dr Melanie Bergmann. “In our review, which we jointly conducted with colleagues from Norway, Canada and the Netherlands, we show that this perception no longer reflects the reality. Our northernmost ecosystems are already particularly hard hit by climate change. This is now exacerbated by plastic pollution. And our own research has shown that the pollution continues to worsen.”

Flesh-eating bacteria in Ala Wai Canal could increase threefold by end of century

Field team casting off at the Ala Wai Harbor.
Photo credit: Brian Glazer, UH SOEST

Vibrio vulnificus, a “flesh-eating” bacterium that lives naturally in the water of the Ala Wai Canal in Waikīkī is likely to increase substantially in coming decades, but infections are rare. In recently published research, University of Hawaiʻi at Mānoa scientists highlight the potential for using oceanographic sensors to make accurate predictions of V. vulnificus. By assessing rainfall, water temperature, dissolved nutrients and organic matter the team can forecast potential spikes in levels of the bacteria.

V. vulnificus has been relatively understudied in tropical ecosystems and further, the implications of climate change for this and other coastal human pathogens are generally unknown.

The research team collaborated with the UH Strategic Monitoring and Resilience Training in the Ala Wai Watershed (SMART Ala Wai Program) where at least 20 undergraduate students and six graduate students from the UH Mānoa School of Ocean and Earth Science and Technology (SOEST) participated in sample collection from the canal and processing at the Daniel K. Inouye Center for Microbial Oceanography: Research and Education.

The art of smell: Research suggests the brain processes smell both like a painting and a symphony

What happens when we smell a rose? How does our brain process the essence of its fragrance? Is it like a painting – a snapshot of the flickering activity of cells – captured in a moment in time? Or like a symphony, an evolving ensemble of different cells working together to capture the scent? New research suggests that our brain does both.

“These findings reveal a core principle of the nervous system, flexibility in the kinds of calculations the brain makes to represent aspects of the sensory world,” said Krishnan Padmanabhan, Ph.D., an associate professor of Neuroscience and senior author of the study recently published in Cell Reports. “Our work provides scientists with new tools to quantify and interpret the patterns of activity of the brain.”

Researchers developed a model to simulate the workings of the early olfactory system – the network the brain relies on for smelling. Employing computer simulations, they found a specific set of connections, called centrifugal fibers, which carry impulses from other parts of the central nervous system to the early sensory regions of the brain, played a critical role. These centrifugal fibers act as a switch, toggling between different strategies to efficiently represent smells. When the centrifugal fibers were in one state, the cells in the piriform cortex – where the perception of an odor forms – relied on the pattern of activity within a given instant in time. When the centrifugal fibers were in the other state, the cells in the piriform cortex improved both the accuracy and the speed with which cells detected and classified the smell by relying on the patterns of brain activity across time.

These processes suggest the brain has multiple responses to representing a smell. In one strategy, the brain uses a snapshot, like a painting or a photograph, at a given moment to capture the essential features of the odor. In the other strategy, the brain keeps track of the evolving patterns. It is attuned to which cells turn on and off and when – like a symphony.

The dark matter of the brain

Electrical synapses connect neurons in almost all brains; however, little is known about them. A study now shows for the first time where these specific synapses occur in the fruit fly brain and that they influence the function and stability of nerve cells.
Credit: MPI for Biological Intelligence, i.f. / Julia Kuhl

They are part of the brain of almost every animal species, yet they remain usually invisible even under the electron microscope. "Electrical synapses are like the dark matter of the brain," says Alexander Borst, director at the MPI for Biological Intelligence, in foundation (i.f). Now a team from his department has taken a closer look at this rarely explored brain component: In the brain of the fruit fly Drosophila, they were able to show that electrical synapses occur in almost all brain areas and can influence the function and stability of individual nerve cells.

Neurons communicate via synapses, small contact points at which chemical messengers transmit a stimulus from one cell to the next. We may remember this from biology class. However, that is not the whole story. In addition to the commonly known chemical synapses, there is a second, little-known type of synapse: electrical synapse. "Electrical synapses are much rarer and are hard to detect with current methods. That's why they have hardly been researched so far," explains Georg Ammer, who has long been fascinated by these hidden cell connections. "In most animal brains, we therefore don't know even basic things, such as where exactly electrical synapses occur or how they influence brain activity."