How a harmless environmental bacterium became the dreaded hospital germ Acinetobacter baumannii

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

Hospital-acquired infections (HAIs) are often particularly difficult to treat because the pathogens have developed resistance to common antibiotics. The bacterium Acinetobacter baumannii is particularly dreaded in this respect, and research is seeking new therapeutic approaches to combat it. To look for suitable starting points, an international team led by bioinformaticians at Goethe University Frankfurt has compared thousands of genomes of pathogenic and harmless Acinetobacter strains. This has delivered clues about which properties might have made A. baumannii a successful pathogen – and how it might possibly be combated.

Each year, over 670,000 people in Europe fall ill through pathogenic bacteria that exhibit antibiotic resistance, and 33,000 die of the diseases they cause. Especially feared are pathogens that are resistant to several antibiotics at the same time. Among them is the bacterium Acinetobacter baumannii, which is today dreaded above all as a “hospital superbug": up to five percent of all hospital-acquired bacterial infections are caused by this germ alone.

A. baumannii is right at the top of a list of candidates for which, according to the World Health Organization (WHO), new therapies must be developed. This is because the pathogen – due to a flexible genome – easily acquires new antibiotic resistance. At the same time, infections are not only occurring more and more outside the hospital environment but also leading to increasingly severe progression. However, a prerequisite for the development of new therapeutic approaches is that we understand which properties make A. baumannii and its human pathogenic relatives, grouped in what is known as the Acinetobacter calcoaceticus-baumannii (ACB) complex, a pathogen.

How plesiosaurs swam under water

Anna Krahl (front) and Ulrich Witzel used a model made of bone copies and material from the hardware store to reconstruct the muscles. This analog model consists of casts of the front and rear fin, wooden slats, chandelier clamps, eyelets and ropes.
Credit: Ruhr University Bochum

The plesiosaurs are characterized by four uniform fins. Whether they rowed or flew under water could be reconstructed thanks to the combination of paleontological and engineering methods.

Plesiosaurs, which lived around 210 million years ago, have adapted in a unique way to life under water: their front and rear legs have developed into four uniform, wing-like fins in the course of evolution. How they could get on with it in the water, Dr. Anna Krahl worked out in her dissertation supervised at the Ruhr University Bochum and the Rheinische Friedrich-Wilhelms-Universität Bonn. Among other things, by using the finite element method, which is widespread in engineering, it was able to show that the fins had to be twisted in order to advance. Using bones, models and muscle reconstructions, she was able to reconstruct the movement. She reports in the PeerJ journal from 3. June 2022.

Plesiosaurs belong to a group of dinosaurs, the Sauropterygia or paddle lizards, who have adapted to a life in the sea again. They developed in the late Triassic 210 million years ago, lived at the same time as the dinosaurs and died out at the end of the Cretaceous period. Plesiosaurs are characterized by an often extremely elongated neck with a small head - the Elas mosaic animals even have the longest neck of all vertebrates. But there were also large predatory shapes with a rather short neck and huge skulls. In all plesiosaurs, the neck sits on a teardrop-shaped, hydrodynamically well-adapted body with a very shortened tail.

Scientists Show that at Least 44 Percent of Earth’s Land Requires Conservation to Safeguard Biodiversity and Ecosystem Services

Credit Max Melesi on behalf of Koobi Carbon

New research published in the June 3, 2022 journal Science reveals that 44 percent of Earth’s land area – some 64 million square kilometers (24.7 million square miles) requires conservation to safeguard biodiversity.

The team, led by Dr James R. Allan from the University of Amsterdam, used advanced geospatial algorithms to map the optimal areas for conserving terrestrial species and ecosystems across the world. They further used spatially explicit land-use scenarios to quantify how much of this land is at risk from human activities by 2030.

“Our study is the current best estimate of how much land we must conserve to stop the biodiversity crisis - it is essentially a conservation plan for the planet,” said lead author James Allan. “We must act fast, our models show that over 1.3 million square kilometers of this important land – an area larger than South Africa – is likely to have its habitat cleared for human uses by 2030, which would be devastating for wildlife.”

The work has important policy implications since governments are currently negotiating a post-2020 global biodiversity framework under the Convention on Biological Diversity, with new goals and targets for biodiversity which will hopefully come into effect later this year. This will set the conservation agenda for at least the next decade, and governments will have to report progress against these targets on a regular basis.

Tobacco hawkmoths always find the right odor

To collect the nocturnal odor of agave flowers, individual flower umbels on the up to five-meter-high inflorescence are enclosed in foil bags at sunset and connected to a mobile odor collection system.
 Credit: Sonja Bisch-Knaden

A research team at the Max Planck Institute for Chemical Ecology has discovered how tobacco hawkmoths are able to detect odors that are important to them against a complex olfactory background. By looking at the specific activity patterns that the odors triggered in the moths' brains the researcher showed that the sense of smell enables moths not only to perceive the intense floral odors of nectar sources, but also to find the rather unobtrusive smell of their host plants on which the larvae thrive. What is especially amazing is that tobacco hawkmoths can reliably detect the odors of their host plants despite the multitude of background odors emitted by many other plants in the vicinity.

Nocturnal moths, such as tobacco hawkmoths (Manduca sexta), rely primarily on their sense of smell when foraging for flowers that contain nutrient-rich nectar or searching for a host plant on which they lay their eggs. A team of scientists has now turned their attention to the question of how these insects are able to distinguish the odors that are crucial for survival from those that are unimportant in a natural environment full of a wide variety of different odors.

"Our question is based on the fact that the plants that are vital for the tobacco hawkmoth, that is nectar sources and suitable host plants for their offspring, are very sparse in their natural habitat. Apparently, however, these plants are nevertheless found by the moths. We wanted to know whether the olfactory system can also filter out weak odor signals if they provide the moths with clues that lead them to food sources or oviposition sites," says Sonja Bisch-Knaden, lead author of the study. In addition, the researchers were interested in whether female tobacco hawkmoths that have already mated are less receptive to floral odors and more interested in the odors of leaves where they can lay their eggs. This phenomenon has been observed in other moths, such as the moth of the cotton leafworm Spodoptera littoralis.

COVID kidney injury twice as common as diagnosed

A University of Queensland-led study has found millions of COVID-19 patients may have undiagnosed acute kidney injury (AKI).

AKI is a condition where the kidneys suddenly fail to filter waste from the blood, which can lead to serious illness or even death.

Existing data indicates approximately 20 per cent of patients admitted to hospital with COVID-19 develop AKI, rising to roughly 40 per cent for those in intensive care.

But UQ PhD candidate and kidney specialist Dr Marina Wainstein said the true numbers could be double those figures.

“Doctors look at the amount of urine a patient passes and the level of a compound called creatinine in the blood, which rises when the kidneys aren’t working well,” she said.

“However, if that creatinine rise occurs before a patient presents to hospital, we can miss the AKI diagnosis and fail to manage the patient appropriately in those early, critical days of hospitalization.”

Dr Wainstein said when researchers also measured the fall in creatinine levels, which often follows the initial rise, the rate of AKI diagnosis in COVID-19 patients doubled.

Males need not apply

Face of Warramaba flavolineata, one of the two sexual species that crossed to form the parthenogen Warramaba virgo.
Image: Professor Michael Kearney

A unique all-female species of grasshopper that can reproduce without sex provides fascinating insights into evolution; new research led by the University of Melbourne has found.

Published today in Science, the research shows the Australian grasshopper Warramaba virgo (W. virgo) – a parthenogenetic species, meaning it can reproduce asexually by cloning itself – was just as ecologically successful as its counterparts that breed by sex.

Lead author Professor Michael Kearney said the findings were significant because they challenged current evolutionary theory about the advantages of sexual reproduction.

“Most species on earth have two sexes, male and female, that mix their genes when they reproduce. This method of reproduction is thought to increase genetic diversity and ecological success of a species,” Professor Kearney said.

“Parthenogenetic species in theory should be suffering from parasites and a high load of bad mutations. Our study finds no disadvantage to W. virgo compared to other species of grasshoppers that sexually reproduce. In fact, W. virgo has even managed to successfully spread from the west to the east of Australia, unlike its sexual relatives.”

The Legacy of Colonialism Influences Science in the Caribbean

Map of the Caribbean region.
Generated with ArcGIS Pro online.

With the retreat of sprawling empires after the Second World War, one might think the colonial mindset of taking from smaller countries to support large nations would likewise be relegated to the past. But a new paper in The American Naturalist by an international collaboration of researchers shows how the legacy of colonialism remains deeply entrenched within scientific practice across the Caribbean archipelago.

The authors note that a colonial mindset in science, which does not account for the ways humans have interacted with and altered the Caribbean environment for centuries, skews our understanding of these systems. Also, the lack of local involvement in research and the extraction of natural history specimens have come at the expense of former colonies and occupied lands.

“I hope our study encourages more people to think about the impacts of their research and research practices, and to be more involved in the communities they are doing research in,” said Melissa Kemp, an assistant professor of integrative biology at The University of Texas at Austin who has done extensive fieldwork in the Caribbean and is one of the study’s three senior authors.

The paper’s other senior authors are Alexis Mychajliw, an assistant professor at Middlebury College, and Michelle LeFebvre, assistant curator of South Florida Archaeology and Ethnography at the Florida Museum of Natural History. The paper’s lead author is Ryan Mohammed, a Trinidadian biologist and postdoctoral research associate at Williams College.

Counting Cancerous Lymph Nodes Is Best Predictor

Zachary S. Zumsteg, MD,

Patients newly diagnosed with cancer typically focus on one question, eclipsing all others: “What is my prognosis?”

Determining a cancer patient’s prognosis—the likely course and outcome of their disease—typically involves staging the lymph nodes, a process that examines factors such as the lymph node’s size, location and how far the cancer has extended beyond the node. Lymph node staging, however, currently is highly variable, depending on the cancer site, said Zachary S. Zumsteg, MD, assistant professor of Radiation Oncology at Cedars-Sinai Cancer. Because staging helps determine which treatments patients receive, getting it right should be consistent, accurate and universal, which is not always the case, he added.

A study co-led by Zumsteg, recently published in the Journal of the National Cancer Institute, has confirmed the effectiveness of a universal lymph node staging process that potentially may do just that.

“Count the number of metastatic lymph nodes,” Zumsteg said. “We found that this simple process is much better for determining prognoses for solid tumors than all the other factors used today. It should be the backbone of nodal staging because it is the best predictor of mortality, irrespective of the disease site.”

To test their hypothesis that metastatic nodal counting could be used to generate objective and reproducible nodal classification systems for all solid tumors, the researchers performed a retrospective analysis of nearly 1.3 million patients from the National Cancer Database who were diagnosed between 2004 and 2015. The researchers also used data from an additional 2 million patients from the Surveillance, Epidemiology, and End Results registry.

‘Fruitcake’ structure observed in organic polymers

Structure of C16-IDTBT, an organic polymer
Credit: Deepak Venkateshvaran

The field of organic electronics has benefited from the discovery of new semiconducting polymers with molecular backbones that are resilient to twists and bends, meaning they can transport charge even if they are flexed into different shapes.

It had been assumed that these materials resemble a plate of spaghetti at the molecular scale, without any long-range order. However, an international team of researchers found that for at least one such material, there are tiny pockets of order within. These ordered pockets, just a few ten-billionths of a meter across, are stiffer than the rest of the material, giving it a ‘fruitcake’ structure with harder and softer regions.

The work was led by the University of Cambridge and Park Systems UK Limited, with KTH Stockholm in Sweden, the Universities of Namur and Mons in Belgium, and Wake Forest University in the USA. Their results, reported in the journal Nature Communications, could be used in the development of next-generation microelectronic and bioelectronic devices.

Studying and understanding the mechanical properties of these materials at the nanoscale – a field known as nanomechanics – could help scientists fine-tune those properties and make the materials suitable for a wider range of applications.

“We know that the fabric of nature on the nanoscale isn’t uniform, but finding uniformity and order where we didn’t expect to see it was a surprise,” said Dr Deepak Venkateshvaran from Cambridge’s Cavendish Laboratory, who led the research.

Toxic protein ‘variant’ may be the next target for ALS therapies

Penn State College of Medicine researchers studied whether toxic trimers of the protein SOD1 are an intermediate step in the formation of large insoluble aggregates, or whether the trimers form separately off pathway. Their latest study shows toxic trimers form off pathway from large insoluble aggregates formation.
Credit: Penn State College of Medicine

Scientists have long known that proteins can form harmful clusters in neurodegenerative diseases like Alzheimer’s disease, Parkinson’s disease and amyotrophic lateral sclerosis (ALS). But a new study by Penn State researchers shows that ‘variant’ complexes of a protein implicated in ALS pathology form in separate pathways, a discovery which may make it easier for drug developers to design therapies to target the more harmful variant.

Superoxide dismutase (SOD1) is an aggregating protein that contributes to ALS development and progression, though it is unclear which biological mechanisms it uses to do this. Mutations in this protein have been implicated in 15-30% of familial ALS cases and 1-2% of spontaneous ALS cases. Normally existing in a two-part dimer, loss of SOD1 copper or zinc ions can cause it to separate into two separate monomers, or units. Monomers can form form a trimer, or three-part form, or aggregate into larger fibrils, which consist of many SOD1 monomers. Previous research showed that the trimer form is toxic to cells. Other research has suggested that the larger aggregate form may actually have a protective function.