Public fails to appreciate risk of consuming raw milk, survey finds

AMERICAN EXCEPTIONALISM:

Under half of Americans know raw milk is less safe to drink than pasteurized milk

ANNENBERG PUBLIC POLICY CENTER OF THE UNIVERSITY OF PENNSYLVANIA

 

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LESS THAN HALF OF THOSE SURVEYED (47%) SAY RAW MILK IS LESS SAFE TO DRINK THAN PASTEURIZED MILK. FROM AN ANNENBERG PUBLIC POLICY CENTER SURVEY OF 1,031 U.S. ADULTS IN JUNE 2024.

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CREDIT: ANNENBERG PUBLIC POLICY CENTER

PHILADELPHIA – Consuming raw milk or products made with it is riskier than drinking pasteurized milk. Yet fewer than half of U.S. adults know that drinking raw milk is less safe than drinking pasteurized milk and many Americans do not understand the risks of consuming raw milk, according to the Annenberg Public Policy Center’s latest health survey. 

The survey finds that 47% percent of U.S. adults know that drinking raw milk is less safe than drinking pasteurized milk, while nearly a quarter (24%) of Americans either think incorrectly that pasteurization is not effective at killing bacteria and viruses in milk products (4%) or are not sure whether this is true (20%).

“It is important that anyone planning to consume raw milk be aware that doing so can make you sick and that pasteurization reduces the risk of milk-borne illnesses,” said Patrick E. Jamieson, director of the Annenberg Health and Risk Communication Institute at the Annenberg Public Policy Center (APPC) of the University of Pennsylvania.

APPC’s survey was conducted by SSRS, a market research company, on June 7-10, 2024, as a cross-sectional survey of 1,031 U.S. adults who are part of the SSRS Opinion Panel Omnibus. The margin of error for total respondents is ±3.5 percentage points at the 95% confidence level. (See the end of this release or the topline for further details.)

Why consuming raw milk is risky

Milk from animals including cows, sheep, and goats that has not been pasteurized to kill harmful germs is called unpasteurized or raw milk. Unpasteurized dairy products are estimated to “cause 840 times more illnesses and 45 times more hospitalizations than pasteurized products.” The Centers for Disease Control and Prevention (CDC) says that consuming unpasteurized milk and products made from it “can expose people to germs such as Campylobacter, Cryptosporidium, E. coli, Listeria, Brucella, and Salmonella.”

Heightening these concerns, the Food and Drug Administration (FDA) reported in an open letter on June 6, 2024, that bird flu has been detected in cow’s milk. Cattle infected with avian influenza “shed the virus in their milk.” Technically known as highly pathogenic avian influenza virus (HPAI) of the H5N1 subtype, the CDC has noted that H5N1 bird flu is “widespread in wild birds worldwide and is causing outbreaks in poultry and U.S. dairy cows.” The presence of H5N1 bird flu was confirmed in cattle in the United States in mid-March 2024. As of June 21, 2024, there had been four human cases of H5N1 in the United States since 2022, three in April and May of 2024 following exposure to cows and one in April 2022 following exposure to poultry. As of mid-June, 95 cattle herds in 12 states were identified as infected.

The FDA says it does not currently know whether the HPAI H5N1 virus can be transmitted to humans through consumption of raw milk and products made from raw milk from infected cows. However, a study conducted in mice concluded that the virus in “untreated milk can infect susceptible animals that consume it” and the National Institutes of Health (NIH) says this suggests that drinking raw milk “may pose a risk of transmission to people.” As of mid-June 2024, the FDA concluded “that the totality of evidence continues to indicate that the commercial milk supply [which is pasteurized] is safe.”

Although the FDA has prohibited the interstate sale of raw milk since 1987, 30 states in the United States allow the sale of raw dairy milk in some form, according to the NIH. While an FDA food safety report in 2016 said just 4.4% of U.S. adults reported consuming raw milk at least once in the past year, raw milk sales have been increasing, according to the Associated Press, which reports that weekly sales of raw milk from late March to mid-May grew from 21% to as much as 65% over the same period last year.

What people know about the risks of raw milk and benefits of pasteurization

The CDC notes that “pasteurization is crucial for milk safety, killing harmful germs that can cause illness” and the NIH says “dairy milk purchased in the grocery store has been pasteurized – heated to a level high enough and long enough to kill most viruses or bacteria in the milk.”

Yet in the APPC survey, over half of the respondents (54%) either think drinking raw milk is safer (9%), just as safe (15%), or are unsure (30%) whether it is more or less safe than drinking pasteurized milk. Nearly a quarter of those surveyed question the effectiveness of pasteurization at killing bacteria and viruses in untreated milk – 20% are unsure whether it is effective and 4% incorrectly assert that it is not effective.

Who holds correct and mistaken beliefs about raw milk?

An analysis of survey data shows that adults who are 65 and older, college educated, or who identify with the Democratic Party are more likely to understand the benefits of pasteurization and to believe that pasteurization does not destroy the nutrients in milk. The survey finds that Democrats are more likely than Republicans to believe that drinking raw milk is less safe than pasteurized milk (57% vs. 37%). People living in an urban environment also are more likely to believe that raw milk is less safe than pasteurized milk than people in a rural environment (49% vs. 32%).

“The difference in views of raw milk that we see between Democrats and Republicans is difficult to disentangle from the difference between rural and urban dwellers,” said Kathleen Hall Jamieson, director of the Annenberg Public Policy Center. “Those in rural areas are both more likely to identify as Republicans and to consume raw milk.”

However, a regression analysis conducted by APPC research analyst Shawn Patterson Jr. shows that both which political party one identifies with and where one lives independently predict an individual’s beliefs about the safety of raw milk. But the analysis also shows that where one lives does not independently predict beliefs about the effectiveness of pasteurization nor the effect pasteurization has on the nutrients of milk. (See the appendix for regression analysis.)

The nutritional value of pasteurized vs. raw milk

Viral online videos championing the purported benefits of raw milk attracted millions of views between late March, when the presence of bird flu virus was first confirmed in U.S. cattle, and mid-May, according to reports in the Associated Press and Washington Post. Drinking raw milk has been encouraged as well by some political leaders, including presidential candidate Robert F. Kennedy Jr., who told the audience at an October 2022 meeting of his Children’s Health Defense that he drinks raw milk exclusively.

Among the arguments advanced in favor of consuming raw milk is that pasteurization destroys valuable nutrients – but the CDC states that pasteurized milk “offers the same nutritional benefits without the risks of raw milk consumption.”

Our survey finds that less than half of Americans (43%) know that pasteurization “does not destroy nutrients in milk,” while 16% believe that it does destroy nutrients and 41% are not sure. Notably, the survey finds that younger people (18- to 29-year-olds) are more likely to believe than older adults (65 and older) that pasteurization destroys the nutrients in milk (25% vs. 5%) and Republicans are much more likely to believe it than Democrats (23% vs. 8%). Whether one lives in an urban vs. rural setting is not significantly different in this belief.

APPC’s survey

This study was conducted for APPC by SSRS, on its Opinion Panel Omnibus platform. The SSRS Opinion Panel Omnibus is a national, twice-per-month, probability-based survey. Data collection was conducted from June 7–10, 2024 among a sample of 1,031 respondents. The survey was conducted via web (n=1,001) and telephone (n=30) and administered in English (n=1,005) and Spanish (n=26). The margin of error for total respondents is +/-3.5 percentage points at the 95% confidence level. All SSRS Opinion Panel Omnibus data are weighted to represent the target population of U.S. adults ages 18 or older.

In addition to Patrick Jamieson, Kathleen Hall Jamieson, and Shawn Patterson Jr., APPC’s survey team includes Ken Winneg, managing director of survey research.

Download the topline, appendix, and methodology statements.

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The Annenberg Public Policy Center was established in 1993 to educate the public and policy makers about communication’s role in advancing public understanding of political, science, and health issues at the local, state, and federal levels.

Pasteurization inactivates highly infectious avian flu in milk

AMERICAN SOCIETY FOR MICROBIOLOGY

Highlights:

•    In late March 2024, H5N1 bird flu was detected in dairy cattle and then in raw milk.
•    Researchers tested hundreds of milk products from dozens of states for the virus.
•    No infectious virus was found in pasteurized milk products. 
•    Non-infectious traces of viral genetic material were found in 20% of samples. 
 
Washington, D.C.—In March 2024, dairy cows in Texas were found to be infected with highly pathogenic avian flu, or H5N1 bird flu, in the first known case of the virus spreading to cattle. Since then, H5N1 has been found in about 200 animals—and 3 people—across 12 states, according to the Centers for Disease Control and Prevention. The virus was soon detected in raw milk, leading researchers to investigate whether dairy products pose a risk to consumers. 
 
“How far is the virus getting through?” asked Erica Spackman, Ph.D., a virologist at the U.S. Department of Agriculture (USDA) in Athens, Ga. To find out, she and her collaborators tested nearly 300 milk products from 132 processors. 
 
The researchers found no infectious virus in the samples, Spackman and her collaborators report this week in the Journal of Virology, a journal of the American Society for Microbiology. “Milk is safe,” she said. “Just like bacterial pathogens that occur in milk, or other viruses that could occur in milk, the sanitation processes that are in place are getting rid of the pathogens.”
 
The milk processing pipeline includes multiple layers of protection, Spackman said. Microbiological surveillance of milk products can identify pathogens, and milk from cows with mastitis or other disease conditions does not enter the food supply. Finally, heating during the pasteurization process can destroy H5N1 and other, more common bacterial pathogens. 
 
Bird flu primarily infects and spreads among migratory birds and can be transmitted to domestic poultry, but the virus has been detected in other animals as well. Recently, those have included cats, dogs and juvenile goats, as well as a polar bear in Alaska and elephant and fur seals in the Antarctic. However, the discovery of H5N1 on dairy farms in March was a surprise—the virus had never been found in dairy cattle before.
 
Soon after the discovery, diagnostic testing revealed that an infectious form of the virus was present in raw milk, suggesting the virus passes from cow to milk. That finding led the U.S. Food and Drug Administration and the USDA to investigate whether pasteurization effectively eliminated risks posed to consumers. Between April 18 and April 22, 2024, researchers used real-time PCR to analyze 297 samples of pasteurized retail milk products, including 23 types of products, collected from 17 states. 
 
“We did a viability assay to detect live virus and went as sensitive as we could to get even the least little bit of virus, but couldn’t detect anything,” Spackman said. Using PCR, the researchers did identify viral genetic material in 20% of samples. “It looks like the virus is just totally inactivated,” she said.
 
Spackman said the new findings “give us reassurance that what we have been doing— pasteurization—is keeping us safe from what we don’t know about.” 
 

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The American Society for Microbiology is one of the largest professional societies dedicated to the life sciences and is composed of 32,000 scientists and health practitioners. ASM's mission is to promote and advance the microbial sciences.

ASM advances the microbial sciences through conferences, publications, certifications, educational opportunities and advocacy efforts. It enhances laboratory capacity around the globe through training and resources. It provides a network for scientists in academia, industry and clinical settings. Additionally, ASM promotes a deeper understanding of the microbial sciences to diverse audiences.

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JOURNAL

Journal of Virology

 

Moving beyond the 80-year-old solar cell equation

SWANSEA UNIVERSITY

Physicists from Swansea University and Åbo Akademi University have made a significant breakthrough in solar cell technology by developing a new analytical model that improves the understanding and efficiency of thin-film photovoltaic (PV) devices.

For nearly eight decades, the so-called Shockley diode equation has explained how current flows through solar cells; the electrical current that powers up your home or charges the battery bank. However, the new study challenges this traditional understanding for a specific class of next-generation solar cells, namely: thin-film solar cells.

These thin-film solar cells, made of flexible, low-cost materials have had limited efficiency due to factors that the existing analytical models couldn't fully explain.

The new study sheds light on how these solar cells achieve optimal efficiency. It reveals a critical balance between collecting the electricity generated by light and minimising losses due to recombination, where electrical charges cancel each other out.

"Our findings provide key insights into the mechanisms driving and limiting charge collection, and ultimately the power-conversion efficiency, in low-mobility PV devices," said the lead author, Dr Oskar Sandberg of Åbo Akademi University, Finland.

New Model Captures the Missing Piece

Previous analytical models for these solar cells had a blind spot: "injected carriers" - charges entering the device from the contacts. These carriers significantly impact recombination and limited efficiency.

"The traditional models just weren't capturing the whole picture, especially for these thin-film cells with low-mobility semiconductors," explained the principal investigator, Associate Professor Ardalan Armin of Swansea University. "Our new study addresses this gap by introducing a new diode equation specifically tailored to account for these crucial injected carriers and their recombination with those photogenerated."

“The recombination between injected charges and photogenerated ones is not a huge problem in traditional solar cells such as silicon PV which is hundreds of times thicker than next generation thin film PV such as organic solar cells,” Dr Sandberg added.

Associate Professor Armin said: “One of the brightest theoretical physicists of all times, Wolfgang Pauli once said ‘God made the bulk; the surface was the work of the devil’. As thin film solar cells have much bigger interfacial regions per bulk than traditional silicon; no wonder why they get affected more drastically by “the work of the devil” – that is recombination of precious photogenerated charges with injected ones near the interface!”

Impact on Future Solar Cell Development

This new model offers a new framework for designing more efficient thin solar cells and photodetectors, optimising existing devices, and analysing material properties. It can also aid in training machines used for device optimisation marking a significant step forward in the development of next-generation thin-film solar cells.

The article has been published in PRX Energy.

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JOURNAL

PRX Energy

DOI

10.1103/PRXEnergy.3.023008 

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Diode Equation for Sandwich-Type Thin-Film Photovoltaic Devices Limited by Bimolecular Recombination

Using data and clinical research to improve patient care across national borders

Charité intensifies cooperation with CLALIT Health Services

CHARITÉ - UNIVERSITÄTSMEDIZIN BERLIN

During the COVID-19 pandemic, Israel impressively demonstrated how efficient patient data collection can be used to advance research into the prevention of infections and development of therapies. One of Israel's largest healthcare organizations, Clalit Health Services, has since been cooperating with Charité – Universitätsmedizin Berlin with the aim of combining Israeli expertise in the use of "big data" with innovative biomedical research approaches by Charité scientists. As part of the cooperation, one of the first joint projects has now received EU funding. 

Charité – Universitätsmedizin Berlin and Clalit Health Services began working together in a strategic scientific partnership two years ago. "At first glance, both Charité, one of the largest university hospitals in Europe, and Clalit, a health management organization, may appear very different. However, this is precisely what makes this partnership so appealing and holds so much potential," explains Prof. Dr. Heyo Kroemer, CEO of Charité. "Clalit's particular strength lies in its outstanding digital infrastructure and its ability to put innovations such as AI-driven care platforms into practice on a large scale." Clalit Health Services, the largest public healthcare organization in Israel, operates a network of 14 hospitals, over 1,300 primary care clinics, pharmacies, and dental clinics, and serves approximately 5 million members. Through its innovation hub, Clalit Innovation, it promotes advanced research and development.

In June 2022, two Charité scientists – Prof. Friedemann Paul, director of the Experimental and Clinical Research Center and Prof. Leif Erik Sander, director of the Department for Infectious Diseases and Critical Care Medicine – officially initiated the collaboration at a first scientific workshop. At this meeting, ten German-Israeli interdisciplinary research group tandems were established in the fields of AI and health data, immunology and infectious diseases, imaging, oncology, and cardiology. In June of this year, a second follow-up meeting took place at the Charité, where scientists from Tel Aviv and Berlin presented results and plans for ongoing joint projects in more than 40 lectures, and formed new project groups in the fields of women's health and mental health in workshops.  Prof. Dr. Joachim Spranger, Dean of Charité, expressed his enthusiasm at the opening of the event: "The collaboration with Clalit offers unique opportunities to improve data analysis and AI solutions. The processing and use of such high-quality health data makes it possible to better predict disease progression and treatment outcomes,  identify previously unknown disease patterns, and ultimately offer patients suitable diagnostic and therapeutic measures at an early stage.”

EU funds German-Israeli research project
One example of this future-oriented collaboration is the joint Charité and Clalit project EXPLORE – NB, led by PD Dr. Hedwig Deubzer, senior physician at the Charité Department of Pediatrics. It has recently been accepted in the HORIZON 2020 program ERA-NET and received funding of about 939.000 Euro. 

Together with her Israeli colleagues Dr. Esther Berko, Dr. Assaf Grunwald, Dr. Nurit Gal Mark, and other European partners, they will be working intensively over the next three years on the question of whether molecular markers of solid tumors in children, such as neuroblastoma, can also be identified in the so-called biofluids and thus less invasively. Biofluids include blood, bone marrow, urine, and cerebrospinal fluid. The liquid biopsies can be obtained minimally to non-invasively, with low risk, and can therefore be performed serially. Dr. Deubzer emphasizes: " Our hypothesis is that we can monitor therapy response with liquid biopsies and detect and understand the emergence of therapy resistance at an early stage. In EXPLORE-NB, we will focus on epigenetic changes. Our cooperation is based on the research goal of increasing the chances of recovery and improving health monitoring after childhood cancer. Together, we would therefore like to examine the significance of the EXPLORE-NB research data in a clinical study in the future."

Close cooperation despite challenges
Just how close the cooperation is after only two years and despite the pandemic and Middle East conflict is also demonstrated by the visiting professorship for Prof. Ran Balicer, funded by Stiftung Charité. The Israeli physician and public health expert Prof. Balicer will set up a working group at Charité over the next three years as part of Stiftung Charité's Visiting Fellowship Program and continue to promote cooperation between the two institutions. "We find this ongoing collaboration between Charité and Clalit to be of the highest scientific merit and potential clinical impact. The ability of top-notch clinicians and researchers on both sides to use the unparalleled data resources of Clalit has a strong synergistic effect that allows for groundbreaking research on multiple scientific domains," says Prof. Ran Balicer, Chief Innovation Officer of Clalit. He adds: "We are pleased to see the launch of a new cohort of collaborative efforts this week, and are sure these will further increase the beneficial impact this research has on patients' lives and wellbeing – in Germany, in Israel, and worldwide."

About Clalit Health Services 
Clalit is part of Israel's integrated healthcare system, of which around 52 percent of the approximately 10 million residents are members. It is a non-profit organization that integrates primary, specialist, and hospital care. With 14 hospitals, Clalit provides around 30 percent of inpatient beds in Israel. Of the 48,000 employees, 11,000 are doctors and 15,000 are nurses. The annual budget is 13.5 billion dollars.

Clalit Innovation 
Charité International Affairs 
EXPLORE – NB Project 

Australian bushfire ash is deadly for aquatic life

SOCIETY FOR EXPERIMENTAL BIOLOGY

 

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CRAYFISH IN LABORATORY.

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CREDIT: JENELLE MCCUAIG

While the impact of wildfires on terrestrial life has been well studied, only recently has research started to examine the effects of wildfire ash on aquatic organisms. New research reveals that wildfire ash can have lethal consequences on Australian water ecosystems.

Wildfires are becoming more prevalent due to the warming and drying effects of climate change, with Australia becoming especially vulnerable to dangerous bushfires. “Therefore, many Australian species may be threatened by fires,” says Miss Jenelle McCuaig, a Masters student at the University of Alberta, Canada. “This is putting them at greater risk of endangerment and possible extinction.”

Wildfires release ash into the air, which can enter aquatic environments directly or be washed into bodies of water by rainfall. “Once in the water, ash may leach metals and organic combustion products, where they can affect organisms, acquired by ingestion through intestines or respiration through gills,” says Miss McCuaig. There are also serious consequences for humans, as we rely on healthy freshwater ecosystems for water and food.

Miss McCuaig and her team focused their research on two common Australian crustacean species, a crayfish (Cherax destructor) and a shrimp (Macrobrachium australiense).

To examine the effects of wildfire ash on the crustaceans, each species was exposed to a range of ash concentrations to determine their sensitivity and likelihood of survival. Miss McCuaig then measured their oxygen consumption using a respirometry system and took tissue samples to look at their metabolic activity.

After exposure to just 5g of ash per litre of water, Miss McCuaig found that no shrimps could survive – but it took 8 times as much ash to reach complete crayfish mortality. “The huge difference in sensitivity between the two species was much greater than I expected,” says Miss McCuaig.

This research shows that even between similar species, there can be a big difference in survival response to environmental stressors such as wildfire ash. “Differences in body shape and gill structure, as well as habitat preferences, has allowed them to fulfil different niches,” says Miss McCuaig. “Crayfish demonstrated greater resilience to the ash exposure compared to the shrimp.”

For the surviving crayfish and shrimp, the individuals exposed to the highest concentrations of ash had the highest metabolic rates, suggesting a high level of physiological stress. “This is particularly concerning during ash exposure, because increased ventilation means that the animals will be taking up more of the ash particles and leached contaminants from the water, further affecting their body systems.”

“This research will allow us to identify the species that are most threatened by fires and help to inform the development of breeding programs or relocation efforts,” says Miss McCuaig. “When it comes to wildfires, resources are limited, so we must prioritise response actions.”

Miss McCuaig adds that even though many wildfires occur naturally, humans still have a responsibility to protect the living world: “Species conservation begins with wildfire prevention in the first place - it is incredibly important to be educated about, and to implement, fire-safety into our lives to mitigate human-caused wildfires”.

This research was made possible by funding from The Company of Biologists, Natural Sciences and Engineering Research Council of Canada, and the Society for Experimental Biology, as well as collaboration of the Blewett Lab and Franklin Eco-Laboratory.  

This research is being presented at the Society for Experimental Biology Annual Conference in Prague on the 2-5th July 2024.

Shark hatching success drops from 82% to 11% in climate change scenario

SOCIETY FOR EXPERIMENTAL BIOLOGY

 

VIDEO: 

SMALL-SPOTTED CATSHARK EMBRYO IN EGG.

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CREDIT: NOÉMIE COULON

New experimental research shows that the combined effects of ocean warming and acidification could lead to a catastrophic decrease in embryonic shark survival by the year 2100. This research is also the first to demonstrate that monthly temperature variation plays a prominent role in shark embryo mortality.

Oceanic warming and acidification are caused by greater concentrations of CO2 dissolving into marine environments, resulting in rising water temperatures and falling pH levels. “The embryos of egg-laying species are especially sensitive to environmental conditions,” says Noémie Coulon, a PhD student at the Laboratoire de Biologie des Organismes et des Écosystèmes Aquatiques, France. “The hatching success of embryos is a crucial factor for population dynamics. In the case of skates and sharks, which have a slow pace of life, low hatching rates could be critical for population renewal.”

Small-spotted catsharks (Scyliorhinus canicula) are one of the most abundant shark species in Europe. “The small-spotted catshark is already experiencing habitat loss in coastal areas, particularly during the summer months when egg-laying is at its peak,” says Ms Coulon.

Ms Coulon and her team compared small-spotted catshark embryo survival in three environmental scenarios: one control scenario using baseline temperature and pH data from the years 1995 to 2014, and two using predicted climate scenarios for the year 2100 called the Shared Socioeconomic Pathways (SSPs) as outlined in the United Nations’ Intergovernmental Panel on Climate Change’s Sixth Assessment Report released in 2021.

SSP2, known as the “Middle of the Road” scenario, represents a future where slow and non-uniform progress towards tackling climate change is present but net-zero is not reached, and predicts a temperature rise of 2.7°C and drop in pH of 0.2 by the year 2100.

SSP5, known as the “Fossil-fueled Development” scenario, represents a future where fossil fuel resources continue to be more rapidly exploited across the world, and predicts a temperature rise of 4.4°C and drop in pH of 0.4 by the year 2100.

To assess the impact of these different scenarios, Ms Coulon and her team measured embryo growth and yolk consumption within small-spotted catshark eggs every week over a 4-month period, while recording hatching success and growth of surviving baby sharks for 6 months post-hatching.

While the team found a high survival rate for both the control and SSP2 scenarios (81% and 83% respectively), there was a much lower chance of survival for the SSP5 scenario. “We were shocked by the low survival rate observed in the SSP5 scenario, with only 11% of embryos hatching,” says Ms Coulon. The team indicated that the mortality was linked with lower yolk consumption rates, lower growth rates and failure to transition to internal gills.

This research also highlights the importance of seasonal temperature variation, which can significantly increase mortality during critical egg laying periods. “This mortality was most pronounced in August, coinciding with the highest temperatures (reaching 23.1°C), and during a stage of development where embryos undergo gill reabsorption,” explains Ms Coulon.

Ms Coulon and her team noticed that the surviving 11% did not exhibit the typical growth pattern of the other sharks, which may have contributed to their resistance to environmental change: “What makes these individuals special remains unclear, but by acknowledging the inter-individual variation among young marine organisms, we could better evaluate the future ecological success of species.”

This research offers both a serious caution and a beacon of hope for marine species. “Firstly, it serves as a warning about the responses of other species that may be even more sensitive to environmental change,” explains Ms Coulon. “Secondly, our findings demonstrate that the more moderate SSP2 scenario can limit the damage inflicted on species like the small-spotted catshark, which gives us a positive incentive to reduce our greenhouse gas emissions.”

This project has received funding support from the Save Our Seas Foundation. More information can be found here: https://saveourseas.com/project/bringing-up-baby-shark-embryos-and-our-warming-oceans.

This research is being presented at the Society for Experimental Biology Annual Conference in Prague on the 2-5th July 2024.

Young small-spotted catsharks [VIDEO] |

Young small-spotted catsharks in laboratory.

 

Small-spotted catshark embryo in egg.

CREDIT

Noémie Coulon

Artificial light is a deadly siren song for young fish

SOCIETY FOR EXPERIMENTAL BIOLOGY

 

IMAGE: 

LIGHT POLLUTION AT NIGHT OVER AQUATIC HABITATS IN FRENCH POLYNESIA.

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CREDIT: JULES SCHLIGLER

New research finds that artificial light at night (ALAN) attracts larval fish away from naturally lit habitats, while dramatically lowering their chances of survival in an “ecological trap”, with serious consequences for fish conservation and fishing stock management.

“Light pollution is a huge ongoing subject with many aspects that are still not well understood by scientists,” says Mr Jules Schligler, a PhD student at CRIOBE Laboratory (Centre de Recherches Insulaires et Observatoire de l’Environnement) in Moorea, French Polynesia.

ALAN is the product of human-related activities such as the use of electrical lights along roads, factories, residences and resorts near bodies of water. “ALAN is everywhere and marine wildlife is not exempt to its effects,” says Mr Schligler. “A quarter of the world coastline is impacted and this level is increasing every year.”

Mr Schligler and his team set out to investigate the effects of ALAN on larval recruitment in tropical fish. Larval recruitment is the number of fish that settle in their habitat and survive their juvenile years before becoming an adult. “Larval recruitment is a key life history trait for fish that impacts on stock replenishment and adult fitness,” he says. “Larval fish are also very dependent on the natural light cycle.”

To investigate these effects, Mr Schligler used 48 corals that were split into two treatments: control corals with only natural light exposure, and ALAN corals that were exposed to light pollution at night of a similar intensity that beach resorts and streetlights produce. They focused on two dominant coral reef damselfish native to French Polynesia, the yellowtail dascyllus (Dascyllus flavicaudus) and the blue-green chromis (Chromis viridis).

“First, we monitored fish settlement to the corals to see if they preferred natural or artificial light conditions,” says Mr Schligler. “The fish were then subjected to a range of experiments to better understand the impact of ALAN after they had settled.” These experiments measured various aspects of development and survival such as growth, metabolic rate and risk of predation.

This research finds that many young fish actually prefer environments with artificial light, recruiting 2-3 times as many fish than naturally lit environments.

The study also reveals the harmful effects of ALAN on fish growth, metabolic rate and overall survival. “ALAN has produced an ecological trap where these fish, misled by human activity, now prefer habitats where their fitness will be lower,” says Mr Schligler. “In other words, ALAN has the potential to attract organisms to a less suitable environment, generating a peculiar anthropogenic stressor."

These results have implications for fish conservation and harvesting policies. “Marine protected areas have only started to consider light pollution in their management policy very recently,” says Mr Schligler. “To better understand fish stock replenishment and conservation, it is crucial to take into account as many factors as we can, such as the rarely considered effects of light pollution.”

This research is being presented at the Society for Experimental Biology Annual Conference in Prague on the 2-5th July 2024.

Experimental coral.

CREDIT

Jules Schligler

Pregnant fish can also get “baby brain”, but not the way that mammals do

SOCIETY FOR EXPERIMENTAL BIOLOGY

 

IMAGE: 

BRAIN STAINING OF PREGNANT FISH. ON THE LEFT IS THE NISSL STAINING USE TO DETERMINE NEURON MORPHOLOGY AND ON THE RIGHT IS KI67 STAINING WHICH STAINS FOR CELL PROLIFERATION.

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CREDIT: TIFFANY ERNST

New research reveals that pregnancy-related brain impairment is present in live-bearing fish, but instead of affecting learning and memory as expected from similar research on mammals, it appears to have a stronger impact on decision-making and sensory reception.

There have been many studies into the detrimental impact of pregnancy on mammalian brains, sometimes called “baby brain” or “momnesia” in humans, revealing how the disruption of neurological processes like neurogenesis, or the creation of new neurons, can affect learning and memory - but this is the first study to examine this phenomenon in fish.

While most fish reproduce by laying eggs, some species are live-bearing, or viviparous, and carry their offspring internally before producing live young. Viviparous species include popular aquarium fish from the family Poeciliidae, such as guppy, molly and platy.

“We wanted to see if these pregnancy-related changes in cognition and neurogenesis occur in other live-bearing evolutionary lineages, particularly in a species which lacks a placenta,” says Tiffany Ernst, a PhD candidate in the field of developmental and reproductive biology at Wageningen University, Netherlands. “In mammals, the placenta is thought to help regulate pregnancy-related changes to the mother’s brain.”

“The species of fish that I work with, Poeciliopsis gracilis, is especially interesting as they are superfetatious, meaning they can be pregnant with multiple temporally overlapping broods of offspring simultaneously,” says Ms Ernst. “Essentially, my fish are almost constantly pregnant in adulthood - so any detrimental impact on cognition might be more evident in this species.”

“We hoped to learn how pregnancy might induce changes to the maternal brain in a non-mammalian live-bearing species,” says Ms Ernst. “This could help us to understand whether the evolution of a live-bearing reproductive strategy requires neurological trade-offs to adequately adapt for a healthy pregnancy.”

To examine the impact of pregnancy on cognition, pregnant and virgin fish were trained to associate a green disk with the location of food, and then perform a spatial learning task when presented with two seemingly identical disks in different locations. “Then we tested their cognitive flexibility by swapping the locations of the rewarded and non-rewarded disks to see how the fish adjusted to the new location of the food reward,” says Ms Ernst.

To assess the effect on fish neurology, Ms Ernst and the team removed the brains of the pregnant and virgin females and used cell staining to identify areas of new cell proliferation - an indicator of which areas of the brain were producing new cells. This study is the first to map the areas of brain cell proliferation in this species in a “brain atlas”.

Ms Ernst and her team found that while both pregnant and virgin fish were equally successful in both cognitive tasks, pregnant fish were much more hesitant when choosing which disk to approach.

“We also found no difference in cell proliferation in the regions of the brain most responsible for learning and memory,” says Ms Ernst. “However, we were surprised to see that pregnant females exhibited decreased cell proliferation in the regions which contribute to maternal olfactory reception.”

This surprising result suggests that pregnancy compromises the fish’s ability to interpret scent in the water, which may contribute to their choice-aversion in the cognitive tests. “For P. gracilis, reduced choice-propensity during pregnancy might be an adaptive strategy wherein females do not take the risk of foraging for food when the reward is not guaranteed, thus conserving energy for reproduction,” says Ms Ernst.

“Our research indicates that pregnancy may impact maternal cognition and alters brain cell proliferation, but not in the same ways as we would expect from mammals,” says Ms Ernst. “This implies that pregnancy across different evolutionary lineages has an impact on the maternal brain which in turn, affects how mothers cognitively and physiologically adapt to the burdens of live-bearing reproduction.”

This research is being presented at the Society for Experimental Biology Annual Conference in Prague on the 2-5 th July 2024.

 

Starfish skeleton inspires new 4D morphing structure

SOCIETY FOR EXPERIMENTAL BIOLOGY

 

IMAGE: 

MORPHING STRUCTURE HOLDING POT PLANT, DEMONSTRATING ITS CAPACITY FOR FLEXIBILITY AND STRENGTH.

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CREDIT: RAMAN RAMAN

Researchers have recently developed a flexible-yet-sturdy morphing structure inspired by the starfish skeleton that exhibits 4D morphing features with promising applications for robotics, aviation, and medical devices.

“Starfish possess the remarkable ability to effortlessly hold themselves in any body posture by changing the stiffness of their endoskeleton,” says Raman, a PhD student in the Biological Structures and Biomimetics workgroup at Hochschule Bremen - City University of Applied Sciences Bremen, Germany. 

Ossicles are calcite microstructures inside starfish bodies that are connected in a network by collagen fibres to form the endoskeleton. This strong but simple structure allows them to hold a wide variety of body postures with minimal energy use.

“We became fascinated with this biological solution to a complex engineering problem,” says Mr Raman. "Our goal was to unlock the secrets of their intricate skeleton and translate those principles into a novel material with similar remarkable properties."

Mr Raman and his team used a multidisciplinary approach for this project. By using high resolution X-ray CT scans, they visualised the starfish skeletal structures and used mathematical models (Finite Element Analysis and Multibody Simulations) to understand the complex interlinked mechanics of the skeletal components.

“For the first time, we are able to show the complex 3D structure of the starfish skeleton and the fine ultrastructure of the small ossicles,” says Mr Raman. “We have now used these insights for the biomimetic design process of our own morphing structure, incorporating rapid prototyping techniques for fabrication.”

Mr Raman and his team have used 3D printing to produce different working prototypes that can accomplish an impressive range of physical challenges. “Our patented starfish-inspired morphing structure shows self-locking, continuous bending, self-healing, and shape memory features,” says Mr Raman.

The scalability, low cost and relative ease of manufacture of this morphing structure provides many opportunities for industry applications, including robotics, aviation, and biomedical devices such as prosthetics and implants.

This study was funded by the German Federal Ministry of Education and Research (BMBF) FHprofUnt 2018 program, project number 13FH150PX8 (JHD, SL) and the Hochschule Bremen PhD scholarship (R).

This research is being presented at the Society for Experimental Biology Annual Conference in Prague on the 2-5th July 2024.

Hand-shaped morphing structure [VIDEO] |

 

Microstructure of the starfish [VIDEO] | 

morphing structure holding a pencil.

CREDIT

Raman Raman