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.

Research Shows How Gulf of Mexico Escaped Ancient Mass Extinction

The Mississippi River flowing into the Gulf of Mexico. According to researchers at the University of Texas Institute for Geophysics, river sediments and ocean currents helped simple sea life in the Gulf survive a deep-ocean mass extinction 56 million years ago.
Credit: U.S. Geological Survey

An ancient bout of global warming 56 million years ago that acidified oceans and wiped-out marine life had a milder effect in the Gulf of Mexico, where life was sheltered by the basin’s unique geology – according to research by the University of Texas Institute for Geophysics (UTIG).

Published in the journal Marine and Petroleum Geology, the findings not only shed light on an ancient mass extinction, but could also help scientists determine how current climate change will affect marine life and aid in efforts to find deposits of oil and gas.

And although the Gulf of Mexico is very different today, UTIG geochemist Bob Cunningham, who led the research, said that valuable lessons can be drawn about climate change today from how the Gulf was impacted in the past.

“This event known as the Paleocene-Eocene Thermal Maximum or PETM is very important to understand because it’s pointing towards a very powerful, albeit brief, injection of carbon into the atmosphere that’s akin to what’s happening now,” he said.

Cunningham and his collaborators investigated the ancient period of global warming and its impact on marine life and chemistry by studying a group of mud, sand, and limestone deposits found across the Gulf.

Less air pollution leads to higher crop yields

Usually, increasing agricultural productivity depends on adding something, such as fertilizer or water. A new Stanford University-led study reveals that removing one thing in particular – a common air pollutant – could lead to dramatic gains in crop yields. The analysis, published June 1 in Science Advances, uses satellite images to reveal for the first time how nitrogen oxides – gases found in car exhaust and industrial emissions – affect crop productivity. Its findings have important implications for increasing agricultural output and analyzing climate change mitigation costs and benefits around the world.

“Nitrogen oxides are invisible to humans, but new satellites have been able to map them with incredibly high precision. Since we can also measure crop production from space, this opened up the chance to rapidly improve our knowledge of how these gases affect agriculture in different regions,” said study lead author David Lobell, the Gloria and Richard Kushel Director of Stanford’s Center on Food Security and the Environment.

A NOx-ious problem

Nitrogen oxides, or NOx, are among the most widely emitted pollutants in the world. These gases can directly damage crop cells and indirectly affect them through their role as precursors to formation of ozone, an airborne toxin known to reduce crop yields, and particulate matter aerosols that can absorb and scatter sunlight away from crops.

How Electric Fish Were Able to Evolve Electric Organs

UT Austin researchers confirmed that the genetic control region they discovered only controls the expression of a sodium channel gene in muscle and no other tissues. In this image, a green fluorescent protein lights up only in trunk muscle in a developing zebrafish embryo.
Image credit: Mary Swartz/Johann Eberhart/University of Texas at Austin.

Electric organs help electric fish, such as the electric eel, do all sorts of amazing things: They send and receive signals that are akin to bird songs, helping them to recognize other electric fish by species, sex and even individual. A new study in Science Advances explains how small genetic changes enabled electric fish to evolve electric organs. The finding might also help scientists pinpoint the genetic mutations behind some human diseases.

Evolution took advantage of a quirk of fish genetics to develop electric organs. All fish have duplicate versions of the same gene that produces tiny muscle motors, called sodium channels. To evolve electric organs, electric fish turned off one duplicate of the sodium channel gene in muscles and turned it on in other cells. The tiny motors that typically make muscles contract were repurposed to generate electric signals, and voila! A new organ with some astonishing capabilities was born.

“This is exciting because we can see how a small change in the gene can completely change where it’s expressed,” said Harold Zakon, professor of neuroscience and integrative biology at The University of Texas at Austin and corresponding author of the study.

In the new paper, researchers from UT Austin and Michigan State University describe discovering a short section of this sodium channel gene—about 20 letters long—that controls whether the gene is expressed in any given cell. They confirmed that in electric fish, this control region is either altered or entirely missing. And that’s why one of the two sodium channel genes is turned off in the muscles of electric fish. But the implications go far beyond the evolution of electric fish.

Small, rare crayfish thought extinct is rediscovered

Dr. Matthew L. Niemiller snorkels in Shelta Cave, where a species of crayfish believed to be extinct was rediscovered. 
Credit: Amata Hinkle

A small, rare crayfish thought to be extinct for 30 years has been rediscovered in a cave in the City of Huntsville in northern Alabama by a team led by an assistant professor at The University of Alabama in Huntsville (UAH).

Dr. Matthew L. Niemiller’s team found individuals of the Shelta Cave Crayfish, known scientifically as Orconectes sheltae, in 2019 and 2020 excursions into Shelta Cave – its only home.

Dr. Niemiller, an assistant professor of biological sciences at UAH, a part of the University of Alabama System, is co-author of a paper on the findings in the journal Subterranean Biology. Besides Dr. Niemiller, authors are UAH’s Katherine E. Dooley and K. Denise Kendall Niemiller, and Nathaniel Sturm of the University of Alabama.

The crayfish’s home is a 2,500-foot cave system that’s owned and managed by the National Speleological Society (NSS) and is unobtrusively located beneath the organization’s national headquarters in northwest Huntsville and is surrounded by subdivisions and bustling roadways.

“The crayfish is only a couple of inches long with diminutive pincers that are called chelae,” Dr. Niemiller says. “Interestingly, the crayfish has been known to cave biologists since the early 1960s but was not formally described until 1997 by the late Dr. John Cooper and his wife Martha.”

Evidence of galactic metal shrouded in dust

NASA’s SOFIA airborne observatory enabled a UCI-led team of astronomers to study infrared emissions from five nearby galaxies. The researchers found more metal than expected in the intergalactic medium, a result that would have been difficult to achieve without the power of viewing infrared radiation through thick galactic dust.
Credit: Jim Ross / NASA

A thorough understanding of galaxy evolution depends in part on an accurate measurement of the abundance of metals in the intergalactic medium – the space between stars – but dust can impede observations in optical wavelengths. An international team of astronomers at the University of California, Irvine, Oxford University in England, and other institutions uncovered evidence of heavier elements in local galaxies – found to be deficient in earlier studies – by analyzing infrared data gathered during a multiyear campaign.

For a paper published recently in Nature Astronomy, the researchers examined five galaxies that are dim in visible wavelengths but trillions of times more luminous than the sun in the infrared. Interactions between these galaxies and neighboring star systems cause gas to shift around and collapse, setting up conditions for prodigious star formation.

“Studying the gas content of these galaxies with optical instruments, astronomers were convinced that they were significantly metal-poor when compared with other galaxies of similar mass,” said lead author Nima Chartab, UCI postdoctoral scholar in physics & astronomy. “But when we observed emission lines of these dusty galaxies in infrared wavelengths, we were afforded a clear view of them and found no significant metal deficiency.”