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Your microbes live on after you die − a microbiologist explains how your necrobiome recycles your body to nourish new life

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Your microbes live on after you die − a microbiologist explains how your necrobiome recycles your body to nourish new life

After you die, bacteria harvest your body for the nutrients that help push daisies.
Matriyoshka/iStock via Getty Images Plus

Jennifer DeBruyn, University of Tennessee

Each human body contains a complex community of trillions of microorganisms that are important for your health while you’re alive. These microbial symbionts help you digest food, produce essential vitamins, protect you from infection and serve many other critical functions. In turn, the microbes, which are mostly concentrated in your gut, get to live in a relatively stable, warm environment with a steady supply of food.

But what happens to these symbiotic allies after you die?

As an environmental microbiologist who studies the necrobiome – the microbes that live in, on and around a decomposing body – I’ve been curious about our postmortem microbial legacy. You might assume that your microbes die with you – once your body breaks down and your microbes are flushed into the environment, they won’t survive out in the real world.

In our recently published study, my research team and I share evidence that not only do your microbes continue to live on after you die, they actually play an important role in recycling your body so that new life can flourish.

Your microbes accompany you from cradle to grave.

Microbial life after death

When you die, your heart stops circulating the blood that has carried oxygen throughout your body. Cells deprived of oxygen start digesting themselves in a process called autolysis. Enzymes in those cells – which normally digest carbohydrates, proteins and fats for energy or growth in a controlled way – start to work on the membranes, proteins, DNA and other components that make up the cells.

The products of this cellular breakdown make excellent food for your symbiotic bacteria, and without your immune system to keep them in check and a steady supply of food from your digestive system, they turn to this new source of nutrition.

Gut bacteria, especially a class of microbes called Clostridia, spread through your organs and digest you from the inside out in a process called putrefaction. Without oxygen inside the body, your anaerobic bacteria rely on energy-producing processes that don’t require oxygen, such as fermentation. These create the distinctly odorous-gases signature to decomposition.

From an evolutionary standpoint, it makes sense that your microbes would have evolved ways to adapt to a dying body. Like rats on a sinking ship, your bacteria will soon have to abandon their host and survive out in the world long enough to find a new host to colonize. Taking advantage of the carbon and nutrients of your body allows them to increase their numbers. A bigger population means a higher probability that at least a few will survive out in the harsher environment and successfully find a new body.

A microbial invasion

If you’re buried in the ground, your microbes are flushed into the soil along with a soup of decomposition fluids as your body breaks down. They’re entering an entirely new environment and encountering a whole new microbial community in the soil.

The mixing or coalescence of two distinct microbial communities happens frequently in nature. Coalescence happens when the roots of two plants grow together, when wastewater is emptied into a river or even when two people kiss.

The outcome of mixing – which community dominates and which microbes are active – depends on several factors, such as how much environmental change the microbes experience and who was there first. Your microbes are adapted to the stable, warm environment inside your body where they receive a steady supply of food. In contrast, soil is a particularly harsh place to live – it’s a highly variable environment with steep chemical and physical gradients and big swings in temperature, moisture and nutrients. Furthermore, soil already hosts an exceptionally diverse microbial community full of decomposers that are well adapted to that environment and would presumably outcompete any newcomers.

Microscopy image of Clostridium septicum
Clostridium septicum is one species of bacteria involved in putrefaction.
Joseph E. Rubin/Flickr, CC BY-NC

It’s easy to assume that your microbes will die off once they are outside your body. However, my research team’s previous studies have shown that the DNA signatures of host-associated microbes can be detected in the soil below a decomposing body, on the soil surface and in graves for months or years after the soft tissues of the body have decomposed. This raised the question of whether these microbes are still alive and active or if they are merely in a dormant state waiting for the next host.

Our newest study suggests that your microbes are not only living in the soil but also cooperating with native soil microbes to help decompose your body. In the lab, we showed that mixing soil and decomposition fluids filled with host-associated microbes increased decomposition rates beyond that of the soil communities alone.

We also found that host-associated microbes enhanced nitrogen cycling. Nitrogen is an essential nutrient for life, but most of the nitrogen on Earth is tied up as atmospheric gas that organisms can’t use. Decomposers play a critical role recycling organic forms of nitrogen such as proteins into inorganic forms such as ammonium and nitrate that microbes and plants can use.

Our new findings suggest that our microbes are likely playing a part in this recycling process by converting large nitrogen-containing molecules like proteins and nucleic acids into ammonium. Nitrifying microbes in the soil can then convert the ammonium into nitrate.

Next generation of life

The recycling of nutrients from detritus, or nonliving organic matter, is a core process in all ecosystems. In terrestrial ecosystems, decomposition of dead animals, or carrion, fuels biodiversity and is an important link in food webs.

Living animals are a bottleneck for the carbon and nutrient cycles of an ecosystem. They slowly accumulate nutrients and carbon from large areas of the landscape throughout their lives then deposit it all at once in a small, localized spot when they die. One dead animal can support a whole pop-up food web of microbes, soil fauna and arthropods that make their living off carcasses.

Insect and animal scavengers help further redistribute nutrients in the ecosystem. Decomposer microbes convert the concentrated pools of nutrient-rich organic molecules from our bodies into smaller, more bioavailable forms that other organisms can use to support new life. It’s not uncommon to see plant life flourishing near a decomposing animal, visible evidence that nutrients in bodies are being recycled back into the ecosystem.

That our own microbes play an important role in this cycle is one microscopic way we live on after death.The Conversation

Jennifer DeBruyn, Professor of Environmental Microbiology, University of Tennessee

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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No need to overload your cranberry sauce with sugar this holiday season − a food scientist explains how to cook with fewer added sweeteners

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theconversation.com – Rosemary Trout, Associate Clinical Professor of Culinary Arts & Food Science, Drexel University – 2024-11-22 07:24:00

Fall means cranberry season − and sweet seasonal holiday dishes.
AP Photo/Sergei Grits

Rosemary Trout, Drexel University

The holidays are full of delicious and indulgent food and drinks. It’s hard to resist dreaming about cookies, specialty cakes, rich meats and super saucy side dishes.

Lots of the healthy raw ingredients used in holiday foods can end up overshadowed by sugar and starch. While adding extra sugar may be tasty, it’s not necessarily good for metabolism. Understanding the food and culinary science behind what you’re cooking means you can make a few alterations to a recipe and still have a delicious dish that’s not overloaded with sugar.

Particularly, if you’re a person living with Type 1 diabetes, the holidays may come with an additional layer of stress and wild blood glucose levels. It’s no time for despair though – it is the holidays, after all.

Cranberries are one seasonal, tasty fruit that can be modified in recipes to be more Type 1 diabetic-friendly – or friendly to anyone looking for a sweet dish without the extra sugar.

I am a food scientist and a Type 1 diabetic. Understanding food composition, ingredient interactions and metabolism has been a literal lifesaver for me.

Type 1 diabetes defined

Type 1 diabetes is all day every day, with no breaks during sleep, no holidays or weekends off, no remission and no cure. Type 1 diabetics don’t make insulin, a hormone that is required to live that promotes the uptake of glucose, or sugar, into cells. The glucose in your cells then supplies your body with energy at the molecular level.

Consequently, Type 1 diabetics take insulin by injection, or via an insulin pump attached to their bodies, and hope that it works well enough to stabilize blood sugar and metabolism, minimize health complications over time and keep us alive.

Type 1 diabetics mainly consider the type and amount of carbohydrates in foods when figuring out how much insulin to take, but they also need to understand the protein and fat interactions in food to dose, or bolus, properly.

In addition to insulin, Type 1 diabetics don’t make another hormone, amylin, which slows gastric motility. This means food moves more quickly through our digestive tract, and we often feel very hungry. Foods that are high in fat, proteins and fiber can help to stave off hunger for a while.

Cranberries, a seasonal treat

Cranberries are native to North America and grow well in the Northeastern and Midwestern states, where they are in season between late September and December. They’re a staple on holiday tables all over the country.

A bowl of cranberries with the zest of an orange on top.
Cranberries are a classic Thanksgiving side dish, but cranberry sauce tends to contain a lot of sugar.
bhofack2/iStock via Getty Images

One cup of whole, raw cranberries contains 190 calories. They are 87% water, with trace amounts of protein and fat, 12 grams of carbohydrates and just over 4 grams of soluble fiber. Soluble fiber combines well with water, which is good for digestive health and can slow the rise of blood glucose.

Cranberries are high in potassium, which helps with electrolyte balance and cell signaling, as well as other important nutrients such as antioxidants, beta-carotene and vitamin C. They also contain vitamin K, which helps with healthy blood clotting.

Cranberries’ flavor and aroma come from compounds in the fruit such as cinnamates that add cinnamon notes, vanillin for hints of vanilla, benzoates and benzaldehyde, which tastes like almonds.

Cranberries are high in pectin, a soluble starch that forms a gel and is used as a setting agent in making jams and jellies, which is why they thicken readily with minimal cooking. Their beautiful red jewel-tone color is from a class of compounds called anthocyanins and proanthocyanidins, which are associated with treating some types of infection.

They also contain phenolics, which are protective compounds produced by the plant. These compounds, which look like rings at the molecular level, interact with proteins in your saliva to produce a dry, astringent sensation that makes your mouth pucker. Similarly, a compound called benzoic acid naturally found in cranberries adds to the fruit’s sourness.

These chemical ingredients make them extremely sour and bitter, and difficult to consume raw. To mitigate these flavors and effects, most cranberry recipes call for lots of sugar.

All that extra sugar can make cranberry dishes hard to consume for Type 1 diabetics, because the sugars cause a rapid rise in blood glucose.

Cranberries without sugar?

Type 1 diabetics – or anyone who wants to reduce the added sugars they’re consuming – can try a few culinary tactics to lower their sugar intake while still enjoying this holiday treat.

Don’t cook your cranberries much longer after they pop. You’ll still have a viscous cranberry liquid without the need for as much sugar, since cooking concentrates some of the bitter compounds, making them more pronounced in your dish.

A line of spoons, each heaped with a pile of powdered spice.
Adding spices to your cranberries can enhance the dish’s flavor without extra sugar.
klenova/iStock via Getty Images

Adding cinnamon, clove, cardamom, nutmeg and other warming spices gives the dish a depth of flavor. Adding heat with a spicy chili pepper can make your cranberry dish more complex while reducing sourness and astringency. Adding salt can reduce the cranberries’ bitterness, so you won’t need lots of sugar.

For a richer flavor and a glossy quality, add butter. Butter also lubricates your mouth, which tends to compliment the dish’s natural astringency. Other fats such as heavy cream or coconut oil work, too.

Adding chopped walnuts, almonds or hazelnuts can slow glucose absorption, so your blood glucose may not spike as quickly. Some new types of sweeteners, such as allulose, taste sweet but don’t raise blood sugar, requiring minimal to no insulin. Allulose has GRAS – generally regarded as safe – status in the U.S., but it isn’t approved as an additive in Europe.

This holiday season you can easily cut the amount of sugar added to your cranberry dishes and get the health benefits without a blood glucose spike.The Conversation

Rosemary Trout, Associate Clinical Professor of Culinary Arts & Food Science, Drexel University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Vulnerability to financial scams in aging adults could be an early indicator of Alzheimer’s disease, new research shows

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theconversation.com – Laura Fenton, PhD student in Clinical Psychology, USC Dornsife College of Letters, Arts and Sciences – 2024-11-22 07:24:00

A brain region called the entorhinal cortex may offer an important puzzle piece to understanding early Alzheimer’s disease.
Andrew Bret Wallis/The Image Bank via Getty Images

Laura Fenton, USC Dornsife College of Letters, Arts and Sciences and Duke Han, USC Dornsife College of Letters, Arts and Sciences

A brain region affected very early in Alzheimer’s disease may explain why some aging people are at greater risk of financial exploitation. That is the key finding of our new study, published in the journal Cerebral Cortex.

We are a clinical psychology doctoral student and a clinical neuropsychologist, and we are interested in understanding whether greater likelihood of being financially exploited – such as being the victim of a scam – may be a behavioral indicator of future cognitive decline.

Other research supports this idea. However, research on associations between vulnerability to financial exploitation and structural brain regions is limited.

We examined the association between vulnerability to financial exploitation and thickness of a brain region called the entorhinal cortex – which is affected very early by Alzheimer’s disease – in a group of 97 adults age 52 to 83 with no signs of cognitive impairment.

The entorhinal cortex is critical for communication between the hippocampus, important for memory retrieval and forecasting oneself into the future, and the ventromedial prefrontal cortex, which is important for value judgments.

We therefore hypothesized that thinning of this region may impair the ability to draw on prior experiences and envision future consequences when assessing the value of certain decisions.

Our study found that lower thickness of the entorhinal cortex, as measured via brain scan, was associated with higher financial vulnerability, as measured by a self-report questionnaire. We did not observe associations between vulnerability to financial exploitation and thickness of two regions of the frontal cortex, the dorsolateral prefrontal cortex and ventromedial prefrontal cortex. These frontal cortex regions are more typically associated with decision-making, but less so with early Alzheimer’s disease.

A senior couple looking unhappy while going through paperwork at home.
Being the victim of a scam could be an early indicator of future cognitive decline.
jeffbergen/E+ via Getty Images

Why it matters

Our primary goal is to aid in early detection of Alzheimer’s disease. Early detection is critically important because Alzheimer’s disease-related brain changes begin decades before significant clinical symptoms emerge. As a result, often by the time a person receives a diagnosis of Alzheimer’s disease, irreparable brain damage has already occurred. This makes intervention and treatment efforts very challenging.

Our study adds to a growing body of work suggesting that impaired financial decision-making may serve as an early behavioral warning sign of future cognitive decline. This could help identify individuals in the early stages of disease when intervention and treatment efforts may be more effective.

Importantly, however, research does not suggest that all older adults who experience financial exploitation will develop Alzheimer’s disease. Indeed, there are many other reasons someone may be at increased risk for financial exploitation, including psychosocial, physical and environmental factors.

Rather, research by our group and others suggests that vulnerability to financial exploitation may serve as one important piece of a risk profile and could alert people to the possible need for further, more comprehensive testing. For example, blood tests for Alzheimer’s disease neuropathology, brain scans and neuropsychological testing could provide people with a more thorough understanding of their risk for future cognitive decline.

What still isn’t known

There are important limitations to our study. We collected all of the data at one time point and did not have specific measurements of Alzheimer’s disease neuropathology. So it is unclear whether differences in thickness were truly the result of Alzheimer’s disease-related brain changes or merely due to preexisting differences or other reasons.

In addition, our participants were primarily white, female and highly educated. This limits our ability to generalize the findings, a gap that will be important to address in future research.

Our lab is following participants over time and adding measures of Alzheimer’s disease pathology to our study. This will help us understand whether changes in brain structure over time lead to increased vulnerability to financial exploitation and whether these changes are associated with early Alzheimer’s disease.

The Research Brief is a short take on interesting academic work.The Conversation

Laura Fenton, PhD student in Clinical Psychology, USC Dornsife College of Letters, Arts and Sciences and Duke Han, Professor of Psychology and Family Medicine, USC Dornsife College of Letters, Arts and Sciences

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Public health surveillance, from social media to sewage, spots disease outbreaks early to stop them fast

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theconversation.com – John Duah, Assistant Professor of Health Services Administration, Auburn University – 2024-11-21 07:21:00

Health officials work to connect the dots during the early stages of an outbreak.
Maxiphoto/iStock via Getty Images Plus

John Duah, Auburn University

A cluster of people talking on social media about their mysterious rashes. A sudden die-off of birds at a nature preserve. A big bump in patients showing up to a city’s hospital emergency rooms.

These are the kinds of events that public health officials are constantly on the lookout for as they watch for new disease threats.

Health emergencies can range from widespread infectious disease outbreaks to natural disasters and even acts of terrorism. The scope, timing or unexpected nature of these events can overwhelm routine health care capacities.

I am a public health expert with a background in strengthening health systems, infectious disease surveillance and pandemic preparedness.

Rather than winging it when an unusual health event crops up, health officials take a systematic approach. There are structures in place to collect and analyze data to guide their response. Public health surveillance is foundational for figuring out what’s going on and hopefully squashing any outbreak before it spirals out of control.

Tracking day by day

Indicator-based surveillance is the routine, systematic collection of specific health data from established reporting systems. It monitors trends over time; the goal is to detect anomalies or patterns that may signal a widespread or emerging public health threat.

Hospitals are legally required to report data on admissions and positive test results for specific diseases, such as measles or polio, to local health departments. The local health officials then compile the pertinent data and share it with state or national public health agencies, such as the U.S. Centers for Disease Control and Prevention.

When doctors diagnose a positive case of influenza, for example, they report it through the National Respiratory and Enteric Virus Surveillance System, which tracks respiratory and gastrointestinal illnesses. A rise in the number of cases could be a warning sign of a new outbreak. Likewise, the National Syndromic Surveillance Program collects anonymized data from emergency departments about patients who report symptoms such as fever, cough or respiratory distress.

Public health officials keep an eye on wastewater as well. A variety of pathogens shed by infected people, who may be asymptomatic, can be identified in sewage. The CDC created the National Wastewater Surveillance System to help track the virus that causes COVID-19. Since the pandemic, it’s expanded in some areas to monitor additional pathogens, including influenza, respiratory syncytial virus (RSV) and norovirus. Wastewater surveillance adds another layer of data, allowing health officials to catch potential outbreaks in the community, even when many infected individuals show no symptoms and may not seek medical care.

Having these surveillance systems in place allows health experts to detect early signs of possible outbreaks and gives them time to plan and respond effectively.

lots of people wearing PPE in a hospital hallway
An extremely busy emergency room could be a signal that an outbreak is underway.
Jeffrey Basinger/Newsday via Getty Images

Watching for anything outside the norm

Event-based surveillance watches in real time for anything that could indicate the start of an outbreak.

This can look like health officials tracking rumors, news articles or social media mentions of unusual illnesses or sudden deaths. Or it can be emergency room reports of unusual spikes in numbers of patients showing up with specific symptoms.

Local health care workers, community leaders and the public all support this kind of public health surveillance when they report unexpected health events through hotlines and online forms or just call, text or email their public health department. Local health workers can assess the information and escalate it to state or national authorities.

Public health officials have their ears to the ground in these various ways simultaneously. When they suspect the start of an outbreak, a number of teams spring into action, deploying different, coordinated responses.

Collecting samples for more analysis

Once event-based surveillance has picked up an unusual report or a sudden pattern of illness, health officials try to gather medical samples to get more information about what might be going on. They may focus on people, animals or specific locations, depending on the suspected source. For example, during an avian flu outbreak, officials take swabs from birds, both live and dead, and blood samples from people who have been exposed.

Health workers collect material ranging from nose or throat swabs, fecal, blood or tissue samples, and water and soil samples. Back in specialized laboratories, technicians analyze the samples, trying to identify a specific pathogen, determine whether it is contagious and evaluate how it might spread. Ultimately, scientists are trying to figure out the potential impact on public health.

Finding people who may have been exposed

Once an outbreak is detected, the priority quickly shifts to containment to prevent further spread. Public health officials turn into detectives, working to identify people who may have had direct contact with a known infected person. This process is called contact tracing.

Often, contact tracers work backward from a positive laboratory confirmation of the index case – that is, the first person known to be infected with a particular pathogen. Based on interviews with the patient and visiting places they had been, the local health department will reach out to people who may have been exposed. Health workers can then provide guidance about how to monitor potential symptoms, arrange testing or advise about isolating for a set amount of time to prevent further spread.

truck advertising 'COVID Trace' app
Many states, including Nevada, set up contact tracing apps to help people determine whether they may have been exposed to the coronavirus.
Gabe Ginsberg/Experience Strategy Associates via Getty Images

Contact tracing played a pivotal role during the early days of the COVID-19 pandemic, helping health departments monitor possible cases and take immediate action to protect public health. By focusing on people who had been in close contact with a confirmed case, public health agencies could break the chain of transmission and direct critical resources to those who were affected.

Though contact tracing is labor- and resource-intensive, it is a highly effective method of stopping outbreaks before they become unmanageable. In order for contact tracing to be effective, though, the public has to cooperate and comply with public health measures.

Stopping an outbreak before it’s a pandemic

Ultimately, public health officials want to keep as many people as possible from getting sick. Strategies to try to contain an outbreak include isolating patients with confirmed cases, quarantining those who have been exposed and, if necessary, imposing travel restrictions. For cases involving animal-to-human transmission, such as bird flu, containment measures may also include strict protocols on farms to prevent further spread.

Health officials use predictive models and data analysis tools to anticipate spread patterns and allocate resources effectively. Hospitals can streamline infection control based on these forecasts, while health care workers receive timely updates and training in response protocols. This process ensures that everyone is informed and ready to act to maximize public safety.

No one knows what the next emerging disease will be. But public health workers are constantly scanning the horizon for threats and ready to jump into action.The Conversation

John Duah, Assistant Professor of Health Services Administration, Auburn University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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