New Research on Antibiotic Resistant Bacteria May Be A Step Toward New Treatments for Infections

 From left to right: NSU Students Gabriela Diaz Tang, Estefania Marin Meneses
Credit: Nova Southeastern University

Antibiotic resistant bacteria pose one of the greatest threats to global public health. In 2019, deaths due to antibiotic resistant bacteria outpaced deaths due to HIV and malaria. Given the lack of innovation in the discovery of new antibiotics, it is critical to determine the mechanisms by which bacteria tolerate existing antibiotics so that we can improve their effectiveness.

One way that bacteria can tolerate antibiotics is through the inoculum effect. Essentially, the higher the density of bacteria in an infection, the more antibiotics are required to treat the infection. While the inoculum effect has been observed for nearly all known antibiotics, and has been documented since the 1960s, a common mechanism to explain inoculum effect for multiple antibiotics has not been found.

Scientists recently discovered that interactions between how fast bacteria grow and the amount of energy (or metabolism) bacteria have can explain the inoculum effect for multiple antibiotics and bacteria species. This new research also shows that providing different nutrients to the bacteria that change growth rate and energy levels can eliminate the inoculum effect.

Scientists discover what was on the menu of the first dinosaurs

Early dinosaurs and their diets. Lesothosaurus is an omnivore, Buriolestes is a carnivore and Thecodontosaurus is an herbivore
Illustration Credit: Gabriel Ugueto

The earliest dinosaurs included carnivorous, omnivorous and herbivorous species, according to a team of University of Bristol paleobiologists.

By looking at the tooth shapes of the earliest dinosaurs and simulating their tooth function with computational modelling, experts were able to compare them to living reptiles and their diets. Their findings, published today in Science Advances, show that many groups of plant-eating dinosaurs were ancestrally omnivorous and that the ancestors of our famous long-necked herbivores, such as Diplodocus, ate meat. This ability to diversify their diets early in their evolution likely explains their evolutionary and ecological success.

The earliest dinosaurs are enigmatic: they were much smaller than their later relatives and for most of the Triassic they were in the shadow of crocodile-like reptiles. It is unknown how diverse they were in terms of diets and ecology, but scientists know something must have happened in the Triassic that allowed dinosaurs to endure the Triassic–Jurassic mass extinction and adapt in its aftermath, becoming the dominant group for the rest of the Mesozoic.

Rosenstiel marine researcher identifies new Bottlenose dolphin subspecies

New subspecies, called the Eastern Tropical Pacific bottlenose dolphin (Tursiops truncatus nuuanu), is smaller than other common bottlenose dolphins.   
Photo Credit: NOAA/NMFS/SWFSC.

A marine researcher at the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science has identified a new bottlenose dolphin subspecies found only in the eastern tropical Pacific Ocean. “While there is a common belief that all dolphin species are already known, improvements in technologies and methodologies are helping to reveal a greater biodiversity in more recent years,” said Ana Costa, Ph.D., a Rosenstiel lecturer specializing in marine mammalogy.

After examining and analyzing a series of specimens, Costa and collaborators of the National Oceanic and Atmospheric Administration, found that the new subspecies, called the Eastern Tropical Pacific bottlenose dolphin (Tursiops truncatus nuuanu), is smaller than other common bottlenose dolphins. These dolphins likely prefer deep offshore waters between southern Baja California and the Galapagos Islands, she added.

Bird Diversity Increased in Severely Burned Forests of Southern Appalachian Mountains

Forest burned in high-severity wildfire.
Photo Credit: Chris Moorman

A new study found bird diversity increased in North Carolina mountain forest areas severely burned by wildfire in 2016, reinforcing that while wildfire can pose risks to safety and property, it can be beneficial to wildlife. The study results could help forest managers better predict bird responses to wildfire, and manage forests to benefit birds.

“It’s important for us to understand the relationships between animals and wildfire dynamics as the climate changes because predictions show more of these high-severity wildfires across the landscape in the future,” said study co-author Chris Moorman, professor of forestry and environmental resources at North Carolina State University.

Wildfires burned more than 235 square miles of forest in the southern Appalachians in the fall of 2016, following a period of dry conditions and acts of arson. In the study published in the journal Forest Ecology and Management, researchers tracked different levels of burn severity in three forest regions of the Nantahala National Forest in western North Carolina.

Astronomers discover clues about stellar ‘glitching’

Stars that experience structural "glitches" during their lifetimes may be more common than first thought.

Astronomers have found a way to peer into the physics of some of the brightest stars in the sky.

Using data from NASA’s Kepler space telescope, an international team of researchers has found new evidence that red giants, dying stars that have exhausted their supply of hydrogen and are in the final stages of stellar evolution, often experience large-scale structural variations, or what are known as “glitches” deep inside their inner core.

The stellar glitches popularized in the media have to do with a star’s rotation, but lead author Mathieu Vrard studies a different kind of defect. The glitches in this study can affect a star’s oscillations, or the frequencies and paths that sound waves travel when passing through a star.

Red clump stars, helium-core burning objects, are often used in astrophysical studies as probes of distance to measure aspects like galaxy density, and to learn more about the physical processes behind stellar chemical evolution. So, it’s vital that scientists understand why these discontinuities happen, said Vrard, a postdoctoral research associate in astronomy at the Ohio State University.

“By analyzing these variations, we can use them to obtain not only the global parameters of the star, but also information on the precise structure of those objects,” he said.

A poison helps to understand hydrogen-producing biocatalysts

Thomas Happe researches biocatalysts that can produce hydrogen in an environmentally friendly way.
 Photo Credit: RUB, Marquard

The toxic cyanide molecule attacks the enzymes, but also enables new insights into catalysis.

In nature, certain enzymes, so-called hydrogenases, are able to produce molecular hydrogen (H2) to produce. Special types of these biocatalysts, so-called [FeFe] hydrogenases, are extremely efficient and therefore of interest for bio-based hydrogen production. Although science already knows a lot about how these enzymes work, some details have not yet been fully clarified. The photobiotechnology working group at the Ruhr University Bochum around Dr. Jifu Duan and Prof. Dr. Close Thomas Happe. The researchers showed that external cyanide binds to the [FeFe] hydrogenases and inhibits hydrogen formation. They were able to demonstrate a structural change in the proton transport path that helps to understand the coupling of electron and proton transport. They report in the journal Angewandte Chemie.

Scientists use materials to make stem cells behave like human embryos

Stem cells confined in a circular shape on a soft gel display characteristic of embryonic development.
Photo Credit: University of New South Wales

A serendipitous discovery in the lab has the potential to revolutionize embryo models and targeted drug therapies.

Materials scientists at UNSW Sydney have shown that human pluripotent stem cells in a lab can initiate a process resembling the gastrulation phase – where cells begin differentiating into new cell types – much earlier than occurs in mother nature.

For an embryo developing in the womb, gastrulation occurs at day 14. But in a lab at UNSW’s Kensington campus, Scientia Associate Professor Kris Kilian oversaw an experiment where a gastrulation-like event was triggered within two days of culturing human stem cells in a unique biomaterial that, as it turned out, set the conditions to mimic this stage of embryo development.

“Gastrulation is the key step that leads to the human body plan,” says A/Prof. Kilian.

“It is the start of the process where a simple sheet of cells transforms to make up all the tissues of the body – nerves, cardiovascular and blood tissue and structural tissue like muscle and bone. But we haven’t really been able to study the process in humans because you can’t study this in the lab without taking developing embryonic tissue.

Untangling the Evolution of Complex Life

Dartmouth researchers report octopuses have high numbers of molecules linked to advanced cognition.
Photo Credit: Diane Picchiottino

Octopuses have captured the attention of scientists and the public with their remarkable intelligence, including the use of tools, engaging in creative play and problem-solving, and even escaping from aquariums. Now, their acuity may provide a critical link in understanding the evolution of complex life and cognition, including the human brain.

An international team led by researchers at Dartmouth and the Max Delbrück Center in Germany report in the journal Science Advances that octopuses are the first known invertebrates—creatures that lack a backbone and constitute roughly 95% of animal species—to contain a high number of gene-regulating molecules known as microRNAs.

The genes of two octopus species show an increase in microRNAs—which are linked to the development of advanced cells with specific functions—over evolutionary time that has so far only been found in humans, mammals, and other vertebrates.

Artificial Intelligence in Veterinary Medicine Raises Ethical Challenges

Chimmi (Chimichanga) a few hours before having his spleen removed due to a mass. Detected by Hi-Def Ultrasound by a radiologist. 7/2021
Photo Credit: Heidi-Ann Fourkiller

Use of artificial intelligence (AI) is increasing in the field of veterinary medicine, but veterinary experts caution that the rush to embrace the technology raises some ethical considerations.

“A major difference between veterinary and human medicine is that veterinarians have the ability to euthanize patients – which could be for a variety of medical and financial reasons – so the stakes of diagnoses provided by AI algorithms are very high,” says Eli Cohen, associate clinical professor of radiology at NC State’s College of Veterinary Medicine. “Human AI products have to be validated prior to coming to market, but currently there is no regulatory oversight for veterinary AI products.”

In a review for Veterinary Radiology and Ultrasound, Cohen discusses the ethical and legal questions raised by veterinary AI products currently in use. He also highlights key differences between veterinary AI and AI used by human medical doctors.

Greenland’s Glaciers Might Be Melting 100 Times As Fast As Previously Thought

A melting glacier on the coast of Greenland.
Photo Credit: Dr. Lorenz Meire, Greenland Climate Research Center.

A computer model has been created by researchers at the Oden Institute for Computational Engineering and Sciences at The University of Texas at Austin that determines the rate at which Greenland’s glacier fronts are melting.

Published in the journal Geophysical Research Letters, the model is the first designed specifically for vertical glacier fronts – where ice meets the ocean at a sharp angle. It reflects recent observations of an Alaskan glacier front melting up to 100 times as fast as previously assumed. According to the researchers, the model can be used to improve both ocean and ice sheet models, which are crucial elements of any global climate model.

“Up to now, glacier front melt models have been based on results from the Antarctic, where the system is quite different,” said lead author Kirstin Schulz, a research associate in the Oden Institute’s Computational Research in Ice and Ocean Systems Group (CRIOS). “By using our model in an ocean or climate model, we can get a much better idea of how vertical glacier fronts are melting.”