Why are mammals more likely to go extinct on islands than on the mainland?

Illustration of Sardinian Dwarf Mammoth, Sardinian Giant Otter, Deer, Sardinian Dhole and Giant Pica
 Illustration Credit: Peter Schouten

Islands are "laboratories of evolution" and home to animal species with many unique features, including dwarfs that evolved to very small sizes compared to their mainland relatives, and giants that evolved to large sizes. A team of researchers from the German Centre of Integrative Biodiversity Research (iDiv) and Martin Luther University Halle-Wittenberg (MLU) has now found that species that evolved to more extreme body sizes compared to their mainland relatives have a higher risk of extinction than those that evolved to less extreme sizes. Their study, which was published in Science, also shows that extinction rates of mammals on islands worldwide increased significantly after the arrival of modern humans.

Islands are hotspots for biodiversity - they cover less than 7% of the Earth’s land area, but account for up to 20% of all terrestrial species on the planet. However, islands are also hotspots for species extinction as 50% of today’s IUCN threatened species are native to islands. 

Invasive Grass in Texas Uses Chemical Warfare to Crowd Out Native Species

Photo Credit: Courtesy of University of Texas at Austin

An invasive grass causing havoc in Texas and contributing to wildfires packs a one-two wallop against native plants. Guinea grass uses a combination of crowding that blocks out light from growing seedlings and what amounts to a chemical warfare in soil that is toxic to native plants, according to a new study by researchers at The University of Texas at Austin.

The findings are published in the journal Ecosphere.

Guinea grass is one of the most ecologically damaging invasive species in the world, arriving in South Texas from Africa more than 100 years ago, to help feed cattle. In the past 20 years, it has spread aggressively across the region and can now be found along roadsides as far north as Austin, bringing with it the risk of more frequent, high-intensity wildfires.

The researchers said knowing about how an invasive species takes over an area is an important step in figuring out how to control and reduce it in the environment.

“The shading and the chemical toxins are each effective at pushing out native plants on their own, but combined, the negative effects increased dramatically,” said Colin Morrison, a graduate student in the Department of Integrative Biology who is the lead author on the paper.

Researchers find access to new fluorescent materials

Cover picture of Chemical Science. The glow of the glow-worm, which represents the class of phospholes, grows more intense as a result of modification.
Illustration Credit: Dr Christoph Selg.

Fluorescence is a fascinating natural phenomenon. It is based on the fact that certain materials can absorb light of a certain wavelength and then emit light of a different wavelength. Fluorescent materials play an important role in our everyday lives, for example in modern screens. Due to the high demand for applications, science is constantly striving to produce new and easily accessible molecules with high fluorescence efficiency. Chemist Professor Evamarie Hey-Hawkins from Leipzig University and her colleagues have specialized in a particular class of fluorescent materials – phospholes. These consist of hydrocarbon frameworks with a central phosphorus atom. In experiments with this substance, Nils König from Hey-Hawkins’ working group has found access to new fluorescent materials. He has now published his findings in the journal Chemical Science.

“Phospholes can be modified by certain chemical reactions, which has a major impact on the color and efficiency of the fluorescence of the molecule. Another special feature of these substances is their propeller-like structure,” explains König. When these molecules are dissolved in a solvent and exposed to UV light, they do not fluoresce. The absorbed energy is released in the form of rotational motion, causing the molecules to spin like a propeller in the solvent. In a crystalline state, however, the ability to rotate is severely limited, which makes the substances fluoresce strongly under UV light. This behavior is known as aggregation-induced emission (AIE).

Cause of leukemia in trisomy 21

Bone marrow smear from a child with Down syndrome who suffers from leukemia. The purple-colored leukemic blasts displace normal blood formation.
Photo Credit: Jan Klusmann, University Hospital Frankfurt

People with a third copy of chromosome 21, known as trisomy 21, are at high risk of developing Acute Myeloid Leukemia (AML), an aggressive form of blood cancer. Scientists led by the Department of Pediatrics at University Hospital Frankfurt have now identified the cause: although the additional chromosome 21 leads to increased gene dosage of many genes, it is above all the perturbation of the RUNX1 gene – a gene that regulates many other genes – that seems to be responsible for AML pathogenesis. Targeting the perturbed regulator could pave the way for new therapies. 

Leukemia (blood cancer) is a group of malignant and aggressive diseases of the blood-forming cells in the bone marrow. Very intensive chemotherapy and in some cases a bone marrow transplant are the only cure. Like all cancers, leukemia is caused by changes in the DNA, the heredity material present in human cells in the form of 46 chromosomes. In many forms of leukemia, large parts of these chromosomes are altered. People with Down syndrome, who have three copies of chromosome 21 (trisomy 21), are highly vulnerable: the risk of developing aggressive Acute Myeloid Leukemia (AML) in the first four years of their life is more than 100 times greater for children with Down syndrome. Down syndrome is the most common congenital genetic disorder, affecting about one in 700 newborn babies. 

Delaying treatment for localized prostate cancer does not increase mortality risk, trial shows

Photo Credit: Max

Active monitoring of prostate cancer has the same high survival rates after 15 years as radiotherapy or surgery, reports the largest study of its kind today. The latest findings from the ProtecT trial, led by the Universities of Oxford and Bristol, are presented today at the European Association of Urology (EAU) Congress in Milan and published in the New England Journal of Medicine.

Although men on active monitoring – which involves regular tests to check on the cancer – were more likely to see it progress or spread than those receiving radiotherapy or surgery, this didn’t reduce their likelihood of survival.

The trial also found that the negative impacts of radiotherapy and surgery on urinary and sexual function persist much longer than previously thought – for up to 12 years.

The findings show that treatment decisions following diagnosis for low and intermediate risk localized prostate cancer do not need to be rushed, according to lead investigator, Professor Freddie Hamdy from the University of Oxford.

Revolutionary new bone cancer drug could save children's lives

Osteosarcoma, Bone Cancer Cell
Cancer that starts in the bones, rather than cancer that has spread to the bone, predominantly affects children and young adults
Image Credit: National Cancer Institute

A new drug that works against the main types of primary bone cancer has been developed by researchers at the University of East Anglia and University of Sheffield.

Cancer that starts in the bones, rather than cancer that has spread to bone, predominantly affects children and young adults.      

Current treatment is brutal, with outdated chemotherapy cocktails and limb amputation leading to life-long disabilities.

Even after these grueling treatments, the five-year survival rate is still poor at just 42 per cent – largely because of how rapidly bone cancer spreads to the lungs. These rates haven’t changed in nearly half a century.

But a new study published in the Journal of Bone Oncology shows how a new drug called ‘CADD522’ blocks a gene associated with driving the cancer’s spread, in mice implanted with human bone cancer.

A pool at Yellowstone is a thumping thermometer

The interval of thumps at Doublet Pool offers insight into the fluctuations of energy in the Yellowstone hydrothermal system.
Photo Credit: Jacob W. Frank / U.S. National Park Service

While the crowds swarm around Old Faithful to wait for its next eruption, a little pool just north of Yellowstone National Park’s most famous geyser is quietly showing off its own unique activity, also at more-or-less regular showtimes. Instead of erupting in a towering geyser, though, Doublet Pool cranks up the bass every 20 to 30 minutes by thumping. The water vibrates and the ground shakes.

Doublet Pool’s regular thumping is more than just an interesting tourist attraction. A new study led by University of Utah researchers shows that the interval between episodes of thumping reflects the amount of energy heating the pool at the bottom, as well as in indication of how much heat is being lost through the surface. Doublet Pool, the authors found, is Yellowstone’s thumping thermometer.

“By studying Doublet Pool, we are hoping to gain knowledge on the dynamic hydrothermal processes that can potentially be applied to understand what controls geyser eruptions,” said Fan-Chi Lin, an associate professor in the department of geology and geophysics at the U and a study co-author, “and also less predictable and more hazardous hydrothermal explosions.”

The study is published in Geophysical Research Letters.

New Tool for Understanding Disease

Lina Pradham (left), a post-doctoral researcher in the Kloxin Group points out dormant breast cancer cells in 3D cultures imaged using confocal microscopy to UD engineer April Kloxin, Thomas and Kipp Gutshall Development Professor of Chemical and Biomolecular Engineering. In the image, the dormant cells (shown in green) are viable, not proliferating, and remain capable of proliferating upon stimulation.
Photo Credit: Evan Krape / University of Delaware

UD model illuminates environmental cues that may contribute to breast cancer recurrence

Nearly 270,000 people in the United States are diagnosed with breast cancer each year. 

According to the Susan G. Komen Foundation, about 70-80% of these individuals experience estrogen receptor-positive (ER+) breast cancer, where cancer cells need estrogen to grow. In terms of treatment, this presence of hormone receptors provides a nice handle for targeting tumors, say with therapies that knock out the tumor cell’s ability to bind to estrogen and prevent remaining breast cancer cells from growing.

However, even if treated successfully, on average, one in five individuals with ER+ breast cancer experiences a late recurrence when dormant tumor cells in distant parts of the body, such as the bone marrow, reactivate anywhere from 5 to over 20 years after initial treatment.

Discovery of T cells’ role in Alzheimer’s, related diseases, suggests new treatment strategy

In Alzheimer’s and related neurodegenerative diseases, the brain protein tau is closely linked to brain damage and cognitive decline. A new study from researchers at Washington University School of Medicine in St. Louis indicates that T cells play a key role in tau-related neurodegeneration, a finding that suggests new treatment strategies for Alzheimer’s and related diseases.
Illustration Credit: Gerd Altmann

Nearly two dozen experimental therapies targeting the immune system are in clinical trials for Alzheimer’s disease, a reflection of the growing recognition that immune processes play a key role in driving the brain damage that leads to confusion, memory loss and other debilitating symptoms.

Many of the immunity-focused Alzheimer’s drugs under development are aimed at microglia, the brain’s resident immune cells, which can injure brain tissue if they’re activated at the wrong time or in the wrong way. A new study from researchers at Washington University School of Medicine in St. Louis indicates that microglia partner with another type of immune cell — T cells — to cause neurodegeneration.

Studying mice with Alzheimer’s-like damage in their brains due to the protein tau, the researchers discovered that microglia attract powerful cell-killing T cells into the brain, and that most of the neurodegeneration could be avoided by blocking the T cells’ entry or activation. The findings, published March 8 in the journal Nature, suggest that targeting T cells is an alternative route to preventing neurodegeneration and treating Alzheimer’s disease and related diseases involving tau, collectively known as tauopathies.

Berkeley researchers present plan for freshwater conservation

Study authors say freshwater conservation priorities should include connectivity, watershed disturbance, flow alteration, water quality, and biodiversity.
(A) Briones Dam reduces connectivity in Bear Creek, California.
(B) Wildfire in Hopland, California, creates widespread watershed disturbance.
(C) poor water quality in Porter Creek, California, kills fish and reduces recreational opportunities.
(D) freshwater ecosystems support biodiversity in Klamath Lake, Oregon.
Photo Credits: (A) L Andrews, (B) P Parker Shames, (C) G Rossi, (D) J Shames

The 30x30 initiative is a global effort to set aside 30% of land and sea area for conservation by 2030, a move scientists hope will reverse biodiversity loss and mitigate the effects of climate change. Now adopted by state and national governments around the world, 30x30 creates an unprecedented opportunity to advance global conservation.

When it comes to the water side of 30x30, most programs focus primarily on conservation of oceans, but a new study by researchers at the University of California, Berkeley argues that freshwater ecosystems must not be neglected. Published today in the journal Frontiers in Ecology and the Environment, the paper urges policy makers to explicitly include freshwater ecosystems like rivers, lakes, and wetlands in 30x30 plans, and outlines how their conservation will be critical to achieving the initiative’s broader goals.