How magnetism could help explain Earth’s formation

Artist's impression of massive impact with proto-Earth.
Image Credit NASA/JPL.

A peculiar property of the Earth’s magnetic field could help us to work out how our planet was created 4.5 billion years ago, according to a new scientific assessment.

There are several theories about how the Earth and the Moon were formed, most involving a giant impact. They vary from a model where the impacting object strikes the newly formed Earth a glancing blow and then escapes, through to one where the collision is so energetic that both the impactor and the Earth are vaporized.

Our theoretical understanding of the Earth’s magnetic field today can actually tell us something about the very formation of the Earth-Moon system.

Now scientists at the University of Leeds and the University of Chicago have analyzed the dynamics of electrically conducting fluids and concluded that the Earth must have been magnetized either before the impact or as a result of it.

They claim this could help to narrow down the theories of the Earth-Moon formation and inform future research into what really happened.

Ocean microbes get their diet through a surprising mix of sources, study finds

Long thought to rely solely on photosynthesis, the microbe Prochlorococcus may get as much as one-third of its carbon through a second strategy: consuming the dissolved remains of other dead microbes. Illustration Credit: Jose-Luis Olivares, MIT

One of the smallest and mightiest organisms on the planet is a plant-like bacterium known to marine biologists as Prochlorococcus. The green-tinted microbe measures less than a micron across, and its populations suffuse through the upper layers of the ocean, where a single teaspoon of seawater can hold millions of the tiny organisms.

Prochlorococcus grows through photosynthesis, using sunlight to convert the atmosphere’s carbon dioxide into organic carbon molecules. The microbe is responsible for 5 percent of the world’s photosynthesizing activity, and scientists have assumed that photosynthesis is the microbe’s go-to strategy for acquiring the carbon it needs to grow.

But a new MIT study in Nature Microbiology today has found that Prochlorococcus relies on another carbon-feeding strategy, more than previously thought.

Organisms that use a mix of strategies to provide carbon are known as mixotrophs. Most marine plankton are mixotrophs. And while Prochlorococcus is known to occasionally dabble in mixotrophy, scientists have assumed the microbe primarily lives a phototrophic lifestyle.

The new MIT study shows that in fact, Prochlorococcus may be more of a mixotroph than it lets on. The microbe may get as much as one-third of its carbon through a second strategy: consuming the dissolved remains of other dead microbes.

The importance of light for grassland plant diversity

Light experiment at the Global Change Experimental Facility (GCEF) of the UFZ research station in Bad Lauchstädt.
Photo Credit: Anu Eskelinen / University of Oulu

Plants need light to grow. However, due to excess nutrients and/or the absence of herbivores less light can reach lower vegetation layers in grasslands. Consequently, few fast-growing species dominate and plant diversity declines. So far, this relationship has been established indirectly through experiments, but never directly by means of experimentally adding light in the field. Now, an international team of researchers including scientists from the Helmholtz Centre for Environmental Research (UFZ), the Martin Luther University Halle-Wittenberg (MLU) and the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, was able to experimentally prove the dominant role of light competition for the first time. The results have been published in Nature.

The team of researchers led by Prof. Dr. Anu Eskelinen from the University of Oulu (Finland) used the Global Change Experimental Facility (GCEF) at the UFZ research station in Bad Lauchstädt for their experiments. Scientists from UFZ, iDiv and various universities use the GCEF platform to study the influence of different climate models and land use intensities on plant community structure - specifically food webs and interactions between species.

Bacterial armor plating has implications for antibiotics

Magnified view of the E. coli outer membrane showing hexagonal clustering of proteins (red/green), alongside body armor for comparison. The black background represents lipids that are shared between neighboring proteins.
Image Credit: Dheeraj Prakaash and Syma Khalid Department of Biochemistry, University of Oxford

A new study published in the journal Science Advances sheds light on how Gram-negative bacteria like E. coli construct their outer membrane to resemble body armor, which has far-reaching implications for the development of antibiotics.

Professor Colin Kleanthous in the Department of Biochemistry at the University of Oxford led the interdisciplinary study, with contributions from colleagues in Oxford and University College London. They undertook a microscopic examination of the outer membrane of E. coli to understand the molecular basis for the protection it affords against many classes of antibiotics. E. coli causes infections such as pneumonia, UTIs and sepsis that are notoriously difficult to treat due to multidrug resistance.

The outer membrane is composed of two types of lipids that stack on top of each other, an unusual arrangement which, it was thought, is solely responsible for making the membrane resistant to antibiotics. As well as lipids, the outer membrane contains numerous proteins which the bacterium relies on to acquire nutrients and excrete waste products. Textbooks classically show these proteins dotted randomly in the membrane, contributing little to its stability or structure.

The discovery of Professor Kleanthous and colleagues came from them asking a simple question: do protein interactions play any role in the structural integrity of the outer membrane?

Association between poor sleep quality and an increased risk of developing Alzheimer's

Photo Credit: Claudio_Scott

New research has shown an association between sleep quality – less than seven hours - and Alzheimer's disease-related pathology in people without cognitive impairment. The study by an international team led by the Pasqual Maragall Foundation research centre, the Barcelonaβeta Brain Research Centre (BBRC), together with researchers from the University of Bristol and North Bristol NHS Trust, is published in the scientific journal Brain Communications today [3 November].

The results of the analysis, part of the European Prevention of Alzheimer's Dementia Longitudinal Cohort Study (EPAD LCS), indicate that poor sleep quality is related to an increase in pathology of Alzheimer's disease. This finding is relevant to help define future therapies, so that they can be targeted at the appropriate phase of the disease.

A cross-sectional analysis of sleep quality

Sleep abnormalities are common in Alzheimer's disease, and sleep quality can be affected early in the preclinical stage of the disease, even when no other symptoms are experienced. Understanding how and when sleep deprivation contributes to Alzheimer's disease progression is important for the design and implementation of future therapies.

Laura Stankeviciute, a predoctoral researcher at the BBRC and one of the main authors of the study, said: "The epidemiological and experimental data available to date already suggested that sleep abnormalities contribute to the risk of Alzheimer's disease.

"However, previous studies had limitations due to the lack of biomarkers of Alzheimer's disease, because they had a non-cross-sectional design, or because of the small size of the sample of participants.” This is the first study to include all of these factors.

Plant Hormones to Help Prevent Striga Invasion

 A field of the crop sorghum infected with Striga.
Photo Credit: 2022 KAUST; Muhammad Jamil; Jian You Wang.

As part of a multipronged approach to prevent infestations by the parasitic plant Striga hermonthica, researchers are unravelling the role of plant hormones, known as strigolactones (SLs).

Cereal crops release SLs that regulate plant architecture and play a role in other processes related to plant development and stress response. The SLs released by plant roots attract mycorrhizal fungi, which provide plant nutrients. But strigolactones also induce germination and invasion by the parasitic plant Striga, with severe impacts on agricultural production, particularly on cereal yields in Africa.

In an important discovery, the team has recently shown that canonical SLs do not affect plant architecture in rice.

The researchers employed CRISPR/Cas9 technology to generate rice lines without canonical SLs and compared them to wild-type plants. The shoot and root phenotypes did not differ significantly between the mutants and the wild type, indicating that canonical SLs are not major regulators of rice architecture.

“Knowing which SLs regulate plant architecture and other functions, such as establishing symbiosis with beneficial mycorrhizal fungi or enabling invasion by root parasitic plants, will allow us to optimize and engineer one trait without affecting others,” explains Jian You Wang, a postdoc in Al-Babili’s lab.

The research showed that canonical SLs do contribute to symbiosis with mycorrhizal fungi and play a major role in stimulating seed germination in root parasitic weeds.

The unintended consequences of using a ventilator

Higher strains caused by artificial ventilators (left) and less stretch when the same lung is made to breathe naturally.
Photo Credit: Mona Eskandari/UCR

Breakthrough research addresses a long-standing question in pulmonary medicine about whether modern ventilators overstretch lung tissue. They do.

These cutting-edge findings by UC Riverside researchers were recently published in the American Journal of Respiratory and Critical Care Medicine. They demonstrate major differences between how we naturally breathe versus how ventilators make us breathe. These results are critical, particularly in context of the COVID-19 pandemic and the rush to build ventilators.

“Using novel techniques, we observed that ventilators can overextend certain regions of the lungs,” said Mona Eskandari, UCR assistant professor of mechanical engineering and the BREATHE Center in the School of Medicine, who led the research. These results provide an explanation for the decline in lung health experienced by patients the longer they spend on the machines, especially in the case of disease.

Eskandari’s bMECH lab pioneered a technique to study lungs as they are made to breathe. On a custom-built ventilator designed in their lab, the researchers imitated both natural and artificial breathing. Then, they observed isolated lungs involved in both types of breathing using multiple cameras collecting fast, high-resolution images, a method called digital image correlation.

Oxygen deprivation at birth could increase the risk of cardiovascular disease

Photo Credit: Alexander Grey

An observational study at Karolinska Institutet shows that babies suffering oxygen-deficiency complications at birth are almost twice as likely to develop cardiovascular disease during childhood and early adulthood as those without such complications. Still, the absolute risk of cardiovascular disease is very low at a young age. The findings are published in the journal The Lancet Regional Health – Europe.

According to the researchers, the study could be the first of its kind to examine how complications related to asphyxiation at birth – something that occurs in about four million babies a year globally – affects the risk of cardiovascular disease later in life. Previous research has mostly concentrated on the association between asphyxia in the neonatal period and brain development.

Despite the relatively high risk, the absolute number of babies who suffer from cardiovascular disease despite asphyxiation at birth is very low. After the 30-year follow-up period, only 0.3 percent of those with asphyxia-related complications had a cardiovascular diagnosis, compared with 0.15 percent of those without complications.

Since the study was observational, the researchers are unable to establish any causality or propose any underlying mechanisms.

Patient-specific cancer tumors replicated in 3D bioprinting advance

Electron micrograph of a grown, hydrogel-embedded tumor spheroid.
Image Credit: University of Bristol

Bowel cancer patients could in future benefit from a new 3D bioprinting technology which would use their own cells to replicate the complex cellular environment of solid tumors in 3D models. The University of Bristol-led advance, published in Biofabrication, would allow clinicians to treat the models, known as spheroids, with chemotherapy drugs and radiation to help them understand an individual patient’s resistance to therapies.

Bowel cancer is the third-most prevalent cancer worldwide, a major cause of cancer-related deaths and is becoming more prevalent globally each year. While current therapies aim to shrink tumors through a combination of surgery, chemotherapy and/or radiotherapy, the heterogenous nature of bowel tumors mean that chemotherapy drugs have variable effects between patients.

In this new study, researchers developed a new 3D bioprinting platform with high content light microscopy imaging and processing. Using a mixture of bioinks and colorectal (bowel) cancer cells, the team showed they were able to replicate tumors in 3D spheroids.

To investigate how the tumors might respond to drugs, dose-response profiles were generated from the spheroids which had been treated separately with chemotherapy drugs oxaliplatin (OX), fluorouracil (5FU), and radiotherapy. The spheroids were then imaged over time. Results from their experiment showed oxaliplatin was significantly less effective against tumor spheroids than in current 2D monolayer culture structures, when compared to fluorouracil.

How Cells Find the Right Partners

Fluorescence microscopy images of Drosophila egg chambers of different developmental stages. Eya in the epithelial cells is depicted in orange.
Image Credit: Vanessa Weichselberger/University of Freiburg

During the growth and development of living organisms, different types of cells must come into contact with each other in order to form tissues and organs together. A small team working with Prof. Dr. Anne Classen of the Excellence Cluster CIBSS – Centre for Integrative Biological Signaling Studies of the University of Freiburg has discovered that complex changes in form, or morphogenesis, during development are driven exclusively via the affinity of cells to each other. The researchers examined the egg chambers of fruit flies (Drosophila melanogaster) and combined genetic methods and mathematical modeling in their work. The study has been published in the scientific journal Nature Communications.

Complex organization processes in egg chamber

The lead author of the study and a member of Classen’s lab, Dr. Vanessa Weichselberger, summarized the team’s work: “We wanted to find out how different types of cells organize their morphogenesis with each other in order to form functional units.” She continues, “The egg chamber is a good example, because within it, different cell populations must self-organize into functional units.” The egg chamber is the structure in which an immature egg cell, or oocyte, matures until it is ready for fertilization. Drosophila’s egg chamber looks like a tiny football. Inside, the growing egg cell is located on one side, and on the other are 15 nurse cells that provide nutrients for the immature egg cell. In order to produce an egg, the egg cell must mature, while the nurse cells are ultimately removed.

Both processes – the maturation of the egg cell and the removal of the nurse cells, are dependent on an external layer of epithelial cells. For this purpose, the epithelial cells are divided into specialized groups, which – based on their function – must either make contact with the nurse cells or the egg cell. This partnering between the inner and outer cells is a complex process which takes place while simultaneously the size relationships within the egg chamber continually change. “Until now, the mechanisms that could robustly control such a dynamic process were unknown,” says Classen.