New analysis yields clearer picture of toxin-producing blue-green algae blooms

2024 cyanobacterial bloom at Detroit Reservoir
Photo Credit: Elijah Welch, city of Salem.

A long-term analysis shows that a major Oregon reservoir abruptly swapped one type of toxic algae for another midway through the 12-year study period, absent from any obvious cause. 

The project provides a novel look at harmful algal blooms, or HABs which pose multiple health risks to people and animals worldwide. 

Harmful algal blooms in lakes and reservoirs are explosions of cyanobacteria, often referred to as blue-green algae. Microscopic organisms ubiquitous in all types of water around the globe, cyanobacteria use sunlight to make their own food and in warm, nutrient-rich environments can quickly multiply, resulting in blooms that spread across the water’s surface. 

These blooms can form at any time of the year but most often occur between spring and fall. Some types of cyanobacteria produce liver toxins and neurotoxins, while others make toxins that can cause gastrointestinal illness if swallowed and acute rashes upon contact with skin. 

UQ scientists uncover secrets of yellow fever

Dr Summa Bibby
Photo Credit: The University of Queensland

University of Queensland researchers have captured the first high-resolution images of the yellow fever virus (YFV), a potentially deadly viral disease transmitted by mosquitoes that affects the liver.

They’ve revealed structural differences between the vaccine strain (YFV-17D) and the virulent, disease-causing strains of the virus.

Dr Summa Bibby from UQ’s School of Chemistry and Molecular Bioscience said despite decades of research on yellow fever, this was the first time a complete 3D structure of a fully mature yellow fever virus particle had been recorded at near-atomic resolution.

“By utilising the well-established Binjari virus platform developed here at UQ, we combined yellow fever’s structural genes with the backbone of the harmless Binjari virus and produced virus particles that could be safely examined with a cryo-electron microscope,” Dr Bibby said.

“Atlas” of mouse microbiome strengthens reproducibility of animal testing

Prof. Dr. Bahtiyar Yilmaz, Research group leader at the Department for Biomedical Research (DBMR) of the University of Bern and Department of Visceral Surgery and Medicine, Inselspital, Bern University Hospital.
Photo Credit: © Courtesy of Bahtiyar Yilmaz

Laboratory mice are indispensable for biomedical discovery, yet even genetically identical mice can yield conflicting experimental results depending on their resident microbiota. The complex interplay between microbial communities and their associated metabolic functions in the intestine can profoundly influence experimental results, therapeutic interventions, and our understanding of various biological processes. Understanding the dynamics of the gut microbiome is therefore of paramount importance for biomedical research, as it plays a vital role in shaping health and disease outcomes. This groundbreaking study addresses a fundamental question in microbiome science: how does the composition of microbial communities affect their metabolic function? By exploring this relationship, the research aims to provide insights that could lead to more effective strategies for utilizing mouse models in biomedical studies. 

Led by researchers from the Department of Biomedical Research of the University of Bern and the Department of Visceral Surgery and Medicine from the Inselspital, Bern University Hospital, this collaborative effort involved a vast global consortium, that meticulously analyzed approximately 4,000 intestinal samples from mice. The study forms the geographically most comprehensive mouse microbiome dataset to date and revealed that, despite immense differences in bacterial species across facilities, metabolic outputs in the intestine are strikingly consistent. The findings represent a significant milestone in microbiome research and were recently published in the scientific journal Cell Host & Microbe.

Researchers identify bacteria that could provide an early warning of blue-green algae toxicity

Photo Credit: Lara Jansen.

Researchers at McGill University have identified bacteria that can indicate whether a blue-green algae (cyanobacteria) bloom is likely to be toxic, offering a potential water-safety early warning system. Blooms are becoming more frequent due to climate change, according to previous McGill research. They can produce various contaminants, known as cyanotoxins, that pose serious health risks to humans, pets and wildlife.

The study was led by Lara Jansen in Professor Jesse Shapiro’s lab, in the Department of Microbiology and Immunology. It showed that bacterioplankton populations shift in proportion to the broader bacterial community during a bloom. Jansen conducted the research at McGill as a PhD student, while on exchange from Portland State University.

Some of the bacterioplankton she identified – including some related to those known to break down cyanotoxins – were consistently more abundant in toxic blooms, suggesting that shifts in these bacterial populations may indicate a need for further testing to determine whether the water in a lake has become hazardous.

What Is: The Human Microbiome

The Human Microbiome
Image Credit: Scientific Frontline stock image

The Invisible Organ

The human body is not a sterile, solitary entity. It is a dense, complex, and dynamic ecosystem. Each individual serves as a host to a vast community of microorganisms, collectively known as the human microbiota. This community, which resides in and on the body, is estimated to comprise between 10 trillion and 100 trillion symbiotic microbial cells. Early estimates, which have become a cornerstone of the field, suggested these microbial cells outnumber human cells by a ratio of ten to one. While more recent analyses propose a ratio closer to 1:1, the sheer scale of this microbial colonization remains staggering. These microbial cells, though only one-tenth to one-hundredth the size of a human cell, may account for up to five pounds of an adult's body weight.

This vast microbial community is not a passive passenger. It functions as a "virtual organ" of the body, or more precisely, a "metabolic organ". It is so deeply integrated into our physiology that we are dependent on it for essential life functions, including digestion, immune system development, and the production of critical nutrients.

Sublethal antibiotic levels found to boost spread of resistance genes in the environment by up to 45 times

Photo Credit: Daniel Quiceno M

A new study has found that exposure to sublethal levels of antibiotics, amounts too low to kill bacteria, can increase the spread of antibiotic resistance genes of Escherichia coli (E. coli) found in the environment by up to 45 times.

The study led by researchers from the University of Nottingham and Ineos Oxford Institute for antimicrobial research (IOI) analyzed 39 E. coli strains from a UK dairy farm that were resistant to a group of widely used human critical antibiotics called cephalosporins.

Their findings published in Frontiers journal, showed that all 39 cephalosporin resistant E. coli strains carried the same resistance gene- blaCTX-M-15, which protects bacteria from penicillin and cephalosporin antibiotics

Genetic testing showed the bacteria were almost identical, suggesting a single strain had spread across the farm. Researchers also found that the resistance gene wasn’t fixed in place- it could jump from the bacterial chromosome onto separate small circular double-stranded DNA molecules called plasmids, which can move between bacteria.

Rebalancing the Gut: How AI Solved a 25-Year Crohn’s Disease Mystery

Electron micrographs show how macrophages expressing girdin neutralize pathogens by fusing phagosomes (P) with the cell’s lysosomes (L) to form phagolysosomes (PL), compartments where pathogens and cellular debris are broken down (left). This process is crucial for maintaining cellular homeostasis. In the absence of girdin, this fusion fails, allowing pathogens to evade degradation and escape neutralization (right).
Image Credit: UC San Diego Health Sciences

The human gut contains two types of macrophages, or specialized white blood cells, that have very different but equally important roles in maintaining balance in the digestive system. Inflammatory macrophages fight microbial infections, while non-inflammatory macrophages repair damaged tissue. In Crohn’s disease — a form of inflammatory bowel disease (IBD) — an imbalance between these two types of macrophages can result in chronic gut inflammation, damaging the intestinal wall and causing pain and other symptoms. 

Researchers at University of California San Diego School of Medicine have developed a new approach that integrates artificial intelligence (AI) with advanced molecular biology techniques to decode what determines whether a macrophage will become inflammatory or non-inflammatory. 

The study also resolves a longstanding mystery surrounding the role of a gene called NOD2 in this decision-making process. NOD2 was discovered in 2001 and is the first gene linked to a heightened risk for Crohn’s disease.

Dangerous E. coli strain blocks gut’s defense mechanism to spread infection

Isabella Rauch, Ph.D., is the senior author on a new study published in Nature that reveals how a dangerous strain of E. coli blocks the body’s immune defenses to spread infection.
Photo Credit: OHSU/Christine Torres Hicks

When harmful bacteria that cause food poisoning, such as E. coli, invade through the digestive tract, gut cells usually fight back by pushing infected cells out of the body to stop the infection from spreading.

In a new study published today in Nature, scientists from Genentech, a member of the Roche Group, in collaboration with researchers from Oregon Health & Science University, discovered that a dangerous strain of E. coli — known for causing bloody diarrhea — can block this gut defense, allowing the bacteria to spread more easily.

The bacteria inject a special protein called NleL into gut cells, which breaks down key enzymes, known as ROCK1 and ROCK2, that are needed for infected cells to be expelled. Without this process, the infected cells can’t leave quickly, allowing the bacteria to spread more easily.

Fungal secrets of a sunken ship

Robert Blanchette, a professor at the University of Minnesota, and Claudia Chemello, president and co-founder of Terra Mare Conservation, examine the wood of the USS Cairo.
Photo Credit: Paul Mardikian

University of Minnesota researchers studied the microbial degradation of the USS Cairo, one of the first ironclad and steam powered gunboats used in the United States Civil War. Studies of microbial degradation of historic woods are essential to help protect and preserve important cultural artifacts. 

Built in 1861, the ship hit a torpedo and sank in December 1862 and was recovered about 100 years later from the Yazoo River. It's been on display at the Vicksburg National Military Park in Mississippi. Although the ship has a canopy cover, it is exposed to environmental elements. 

Dusty air is rewriting your lung microbiome

UCR researcher collecting dust from the Salton Sea.
Photo Credit: Linton Freund/UCR

Dust from California’s drying Salton Sea doesn’t just smell bad. Scientists from UC Riverside found that breathing the dust can quickly re-shape the microscopic world inside the lungs. 

Genetic or bacterial diseases have previously been shown to have an effect on lung microbes. However, this discovery marks the first time scientists have observed such changes from environmental exposure rather than a disease. 

Published in the journal mSphere, the study shows that inhalation of airborne dust collected close to the shallow, landlocked lake alters both the microbial landscape and immune responses in mice that were otherwise healthy.

“Even Salton Sea dust filtered to remove live bacteria or fungi is altering what microbes survive in the lungs,” said Mia Maltz, UCR mycologist and lead study author. “It is causing deep changes to our internal environment.”

Microbes at Red Sea vents show how life and geology shape each other

Microscopic images of the studied microbes.
Image Credit: Courtesy of King Abdullah University of Science and Technology

A new study led by King Abdullah University of Science and Technology (KAUST) Professor Alexandre Rosado has revealed an unusual microbial world in the Hatiba Mons hydrothermal vent fields of the central Red Sea, a site first discovered by one of his co-authors and colleagues, Assistant Professor Froukje M. van der Zwan. 

Published in Environmental Microbiome, the study delivers the first "genome-resolved" analysis of these hydrothermal systems, providing an unprecedented view into both the types of microbes present and the metabolic functions that sustain them. 

“Microbes from the Hatiba Mons fields show remarkable metabolic versatility,” said KAUST Ph.D. student and lead author of the study, Sharifah Altalhi. “By understanding their functions, we can see how life shapes its environment, and how geology and biology are deeply intertwined in the Red Sea.” 

“Molecular bodyguard” helps infections persist

Joram Waititu and Kemal Avican working together in the Avican Lab at the Department of Molecular Biology, Umeå University.
Photo Credit: Gabrielle Beans

Researchers at Umeå University have identified a key molecular player that helps bacteria survive the hostile environment inside the body. Their study reveals how the protein RfaH acts as a protective shield for bacterial genes — and points to new strategies for fighting persistent infections.

“The human body is a very stressful place for bacteria,” says Kemal Avican research group leader at Department of Molecular Biology and Icelab at Umeå University and leader of the study. “During infection, the immune system attacks, nutrients are scarce, and microbes are exposed to bile salts, acids and heat. We looked at how RfaH helps bacteria deal with that stress by turning on the right survival genes at the right time.”

Persistent bacterial infections pose a major challenge in medicine: bacteria can linger in the body long after acute symptoms fade, evading immune defenses and surviving antibiotic treatment. In diseases like tuberculosis, this leads to relapse and makes treatment difficult.

African Wildlife Poop Sheds Light on What Shapes the Gut Ecosystem

Photo Credit: James C. Beasley

A study of elephants, giraffes and other wildlife in Namibia’s Etosha National Park underscores the ways in which the environment, biological sex, and anatomical distinctions can drive variation in the gut microbiomes across plant-eating species. Because the gut microbiome plays a critical role in animal health, the work can be used to inform conservation efforts.

“This study is valuable because Etosha gave us the opportunity to sample such a large number of species under different environmental conditions,” says Erin McKenney, co-author of a paper on the work and an assistant professor of applied ecology at North Carolina State University. “That gives us meaningful insight into the role the environment plays in shaping the gut microbiome of herbivores.

“Unfortunately, this study may also be important for a second reason,” McKenney says. “Etosha is experiencing devastating wildfires affecting a huge section of the park. Because our samples were taken before the wildfires, these findings could inform recovery efforts by helping us understand how species’ microbiomes are adjusting to changes in diet that stem from the fire’s impact on the landscape.”

“Cocktails” of common pharmaceuticals in our waterways may promote antibiotic resistance

Photo Credit: Nana K.

New research has shown, for the first time, how mixtures of commonly used medications which end up in our waterways and natural environments might increase the development of antibiotic-resistant bacteria.

When humans or animals take medications, as much as 90 percent can pass through the body and into natural environments, via waste-water, or run-off from fields, ending up in the ocean. 

In the environment, this build-up of antibiotic medicines can accumulate to a strength sufficient to kill the bacteria that live there; this can result in bacteria evolving defenses that help them to survive these concentrations, which can mean they are also resistant to antibiotics used to treat them if they later infect humans. However, less is known about how build-up of other medicines also affects bacteria, and until now, scientists have largely investigated the effect of these medications on triggering this antibiotic resistance one-at-a-time. 

New research reveals the secret to ancient fish scales’ survival

Diplomystus dentatus, Fossil-Lake, Wyoming, USA
Photo Credit: Didier Descouens
(CC BY-SA 4.0)

A Curtin University-led international study has solved the mystery of how the skin of a fossilized fish was able to be preserved for 52 million years, extending our understanding of how even the most delicate of biological material can survive deep in time.

Published in Environmental Microbiology, the research examined a remarkably well-preserved specimen of Diplomystus dentatus complete with fossilized skin and scales, found in the ‘Fossil Basin’ region of Wyoming in the United States of America.

Despite being in an oxygen elevated micro-environment which would normally cause tissues to decay, the team discovered the initial degradation of the fish’s fatty skin also led to an environment where phosphate minerals could form and rapidly replace organic material – leading to fossilization.

As the skin broke down, it released fatty acids and hydrogen ions, altering the surrounding chemistry in a way that favored phosphate preservation by effectively blocking the usual carbonate deposits which would have otherwise caused the tissues to decay.

Climate change may increase the spread of neurotoxin in the oceans

The researchers’ findings raise concerns about how climate change may affect the levels of methylmercury in fish and shellfish.
Photo Credit: Johnér Bildbyrå AB

Climate-driven oxygen loss in the Black Sea thousands of years ago triggered the expansion of microorganisms capable of producing the potent neurotoxin methylmercury. That is shown in a new study published in Nature Water, led by Eric Capo at Umeå University, which suggests that similar processes could occur in today’s warming oceans.

Methylmercury is a highly toxic compound that accumulates in fish and seafood, posing severe health risks to humans. It is formed when certain microbes convert inorganic mercury under low-oxygen conditions.

Today, climate change is causing such oxygen-depleted areas to expand in coastal marine environments, including parts of the Baltic Sea. Warmer and more stagnant waters mix less efficiently, and increased algal blooms contribute to oxygen loss in deeper layers, creating ideal conditions for these microbes.

Researchers find key to stopping deadly infection

When rotavirus enters a cell without the FA2H enzyme, it becomes trapped in pockets called endosomes (indicated by red arrows). This prevents the virus from infecting the rest of the cell.
Image Credit: Ding Lab/WashU Medicine

Rotavirus causes severe dehydrating diarrhea in infants and young children, contributing to more than 128,500 deaths per year globally despite widespread vaccination efforts. Although rotavirus is more prevalent in developing countries, declining vaccination uptake in the United States has resulted in increasing cases in recent years.

New research from Washington University School of Medicine in St. Louis has identified a key step that enables rotavirus to infect cells. The researchers found that disabling the process in tissue culture and in mice prevented infection. This discovery opens up new avenues for therapeutic intervention to treat rotavirus and other pathogens that rely on the same infection mechanism.

“Rotavirus kills infants and children, young people who never had a chance at life,” said Siyuan Ding, an associate professor of molecular microbiology at WashU Medicine. “That’s why we want to develop effective therapeutics, even though we already have vaccines that we can use. Not all kids receive the vaccine, and this virus is very infectious. Once a child has the virus, there’s currently no treatment; we can only manage the symptoms.”

Changes in gut microbiota influence which patients get AIG-related neuroendocrine tumors

Researchers took biopsies of AIG patients with and without neuroendocrine tumor growth to understand their bacterial communities
Image Credit: Osaka Metropolitan University

Researchers from Osaka Metropolitan University have discovered how the balance of bacteria in the stomach affects the growth of neuroendocrine tumors (NETs). By identifying the specific bacteria involved and the biochemical reactions that cause tumor growth, the researchers hope to create a new diagnostic technique to detect which patients are most likely to develop cancer.

Autoimmune gastritis (AIG) is a long-term condition in which the body’s immune system mistakenly attacks the lining of the stomach. This ongoing immune response gradually damages the stomach, affecting how it functions and its ability to protect itself from harmful agents. Over time, these changes can increase the risk of developing NETs, a type of tumor that develops from hormone-producing cells in the stomach.

Researchers revive yoghurt made from... ants

Photo Credit: David Zilber

An old traditional recipe for yoghurt made from ants has been recreated by researchers at the University of Copenhagen. In a new study, they show how ants and the bacteria that live on them can transform milk into yoghurt. This provides new knowledge about the food traditions of the past and one of today's major food trends, and the study may also inspire new sustainable foods.

Take four live forest ants. Put them in a jar of warm milk. Cover with a piece of cloth, then place the jar in a colony overnight. Voila! Now you have tasty yoghurt. This is how yoghurt was made for generations in many parts of Turkey and the Balkans. Today, the tradition has largely died out. But what is actually the science behind the method? And what can modern research learn from this method?

A team of biologists, food scientists and anthropologists from the University of Copenhagen and DTU, among others, set out to investigate this in collaboration with chefs from the Michelin-starred restaurant The Alchemist. No one has ever described the biology behind this mysterious recipe.

Microbial DNA sequencing reveals nutrient pollution and climate change reinforce lake eutrophication

Lake 227 of the Experimental Lakes Area.
Photo Credit: Rebecca Garner

The algal blooms increasingly seen in Canadian lakes have been linked to both nutrient pollution from agricultural runoff and climate change. However, a new Concordia-led study using DNA sequencing of lakebed microbes reveals that these two drivers amplify each other in ways that profoundly affect the health of lake ecosystems.

Using records and samples from the International Institute for Sustainable Development Experimental Lakes Area (ELA), a group of 58 lakes in northwestern Ontario designated freshwater research facilities, the researchers paired environmental monitoring data dating back more than five decades with paleogenetic reconstructions from lakebed microbes dating back more than a century.

By sequencing DNA found in lake sediments, the researchers got insight into past algal communities’ composition and compare them to communities today. This provided critical insight into how those communities changed over decades.

“The sediment DNA archives gave us a chronology of these lakes’ history,” says lead author Rebecca Garner, PhD 2023, and currently a postdoctoral fellow at the University of California, Berkeley. “This is the first study to show that we can reconstruct the community dynamics of that ecosystem and dramatically expands the diversity of microorganisms that we were able to study.”

The study was published in the journal Environmental Microbiology.