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Comment by Dr. Krishna Kumari Challa on April 8, 2025 at 10:43am

Particularly noteworthy is the newly discovered bitter compound oligoporin D, which stimulates the bitter taste receptor type TAS2R46 even at the lowest concentrations (approx. 63 millionths of a gram/liter). To illustrate: the concentration corresponds to one gram of oligoporin D dissolved in about 106 bathtubs of water, where one gram corresponds approximately to the weight of a knife tip of baking soda.

 Lea M. Schmitz et al, Taste-Guided Isolation of Bitter Compounds from the Mushroom Amaropostia stiptica Activates a Subset of Human Bitter Taste Receptors, Journal of Agricultural and Food Chemistry (2025). DOI: 10.1021/acs.jafc.4c12651

Part 2

Comment by Dr. Krishna Kumari Challa on April 8, 2025 at 10:42am

Mushroom study identifies most bitter substance known to date

The molecular world of bitter compounds has so far only been partially explored. Researchers have now isolated three new bitter compounds from the mushroom Amaropostia stiptica and investigated their effect on human bitter taste receptors.

In doing so, they discovered one of the potentially most bitter substances known to date. The study results, published in the Journal of Agricultural and Food Chemistry, expand our knowledge of natural bitter compounds and their receptors, thus making an important contribution to food and health research.

The BitterDB database currently contains more than 2,400 bitter molecules. For about 800 of these very chemically diverse substances, at least one bitter taste receptor is specified. However, the bitter compounds recorded are mainly from flowering plants or synthetic sources. Bitter compounds of animal, bacterial or fungal origin, on the other hand, are still rarely represented in the database.

Researchers assume that bitter taste receptors have developed to warn against the consumption of potentially harmful substances. However, not all bitter compounds are toxic or harmful, and not every toxin tastes bitter, as the example of the death cap mushroom toxin shows. But why is that the case?

Studies have also shown that the sensors for bitter substances are not only found in the mouth, but also in organs such as the stomach, intestines, heart and lungs, as well as on certain blood cells. Since we do not "taste" with these organs and cells, the question arises as to the physiological significance of the receptors there.

Comprehensive data collections on bitter compounds and their receptors could help us to find answers to these open questions.

The more well-founded data we have on the various bitter compound classes, taste receptor types and variants, the better we can develop predictive models using systems biology methods to identify new bitter compounds and predict bitter taste receptor-mediated effects. This applies to both food constituents and endogenous substances that activate extraoral bitter taste receptors.

The research team that undertook this study examined the Bitter Bracket (Amaropostia stiptica) as part of a collaborative project. The mushroom is non-toxic, but tastes extremely bitter.

Using modern analytical methods, the research group  has succeeded in isolating three previously unknown compounds and elucidating their structures. Using a cellular test system, the researchers then showed that the compounds activate at least one of the approximately 25 human bitter taste receptor types.

Part 1

Comment by Dr. Krishna Kumari Challa on April 8, 2025 at 8:57am

Cox proportional hazards models were used to estimate the risk of each condition by obesity class, adjusting for sex, age, race or ethnicity, income, and education. Researchers also calculated population-attributable fractions for each condition by obesity class.

Obesity was present in 42.4% of the study population, including 21.2% with class I obesity, 11.3% with class II, and 9.8% with class III. Compared to those with normal weight, individuals with obesity were more likely to be female, Black, have lower income and education levels, and have higher blood pressure and waist-to-hip ratios.

Prevalence and incidence rates increased progressively with higher obesity classes for all 16 health outcomes. Observed associations with class III obesity were strongest for obstructive sleep apnea (hazard ratio 10.94), type 2 diabetes mellitus (7.74), and metabolic dysfunction–associated liver disease (6.72). Weaker associations were found for asthma (2.14), osteoarthritis (2.06), and atherosclerotic cardiovascular disease (1.96).

Obesity was associated with elevated risk across all subgroups, with consistent patterns by sex and race. Population-attributable fractions showed that obesity explained 51.5% of obstructive sleep apnea cases and 36.3% of metabolic liver disease cases, and 14.0% of all osteoarthritis cases in the study population were estimated to be attributable to obesity.

Increased risk, particularly at higher severity levels, was associated with all 16 health outcomes studied. Risks rose in a stepwise manner across obesity classes, with the highest burden observed among individuals with class III obesity. Findings remained consistent across demographic subgroups and were supported by data from a large, diverse national cohort.

Associations between obesity and several conditions such as sleep apnea, type 2 diabetes, liver disease, and heart failure were strong and statistically robust. Population-attributable fractions indicated that a substantial proportion of these conditions may be preventable through effective obesity management.

Zhiqi Yao et al, Associations between Class I, II, or III Obesity and Health Outcomes, NEJM Evidence (2025). DOI: 10.1056/EVIDoa2400229

Part 2

Comment by Dr. Krishna Kumari Challa on April 8, 2025 at 8:56am

Obesity severity tied to increased risk across 16 common conditions

New research has found that obesity, particularly severe obesity, is strongly associated with the incidence of 16 common health outcomes. Associations remained consistent across sex and racial groups. Strong associations were observed for obstructive sleep apnea, type 2 diabetes, and metabolic dysfunction-associated steatotic liver disease.

Obesity is a risk factor for adverse health outcomes involving multiple organ systems. Prior studies have analyzed conditions individually, limiting understanding of obesity's total health burden. External validity has also been limited by underrepresentation of individuals with class III obesity and of diverse demographic groups.

In the study, "Associations between Class I, II, or III Obesity and Health Outcomes," published in NEJM Evidence, researchers conducted a longitudinal cohort study to understand how different levels of obesity relate to a wide array of health conditions across a diverse U.S. population.

Participants contributed electronic health records, physical measurements, and survey data. Body mass index (BMI) was calculated at enrollment and used to classify individuals as normal weight, overweight, or obese, with further stratification into obesity classes I, II, and III.

Sixteen pre-identified health conditions were evaluated: hypertension, type 2 diabetes, hyperlipidemia or dyslipidemia, heart failure, atrial fibrillation, atherosclerotic cardiovascular disease, chronic kidney disease, pulmonary embolism, deep vein thrombosis, gout, liver disease linked to metabolic dysfunction, biliary calculus, obstructive sleep apnea, asthma, gastroesophageal reflux disease, and osteoarthritis.

Part 1

Comment by Dr. Krishna Kumari Challa on April 7, 2025 at 10:15am

Urban birds host drug-resistant bacteria

Indian cormorants (Phalacocorax fuscicollis) can spread antimicrobial-resistant bacteria in their droppings. Intrigued by the smell of cormorant droppings, veterinary microbiologist Siddhartha Narayan Joardar and his team analysed some of the bird poo and found a strain of E. coli that produced enzymes that helped it resist certain antibiotics. The birds probably pick up the bacterium by eating fish from ponds contaminated by human wastewater, the team suggests. “Growing evidence shows the presence of antimicrobial-resistant bacteria in common urban birds,” says Joardar, which poses a public health threat if it spills over into humans.

https://www.nature.com/articles/d44151-025-00042-0?utm_source=Live+...

https://www.ijah.in/upload/snippet/707_84.pdf

Comment by Dr. Krishna Kumari Challa on April 7, 2025 at 8:47am

When looking at specific dementia subtypes, all unmarried participants also showed reduced risk for Alzheimer's disease and Lewy body dementia. In contrast, no consistent associations were observed for vascular dementia or frontotemporal lobar degeneration in fully adjusted models. Divorced and never-married groups were also less likely to progress from mild cognitive impairment to dementia.

Risk patterns appeared slightly stronger among men, younger individuals, and participants referred to clinics by health professionals. Yet stratified analyses showed minimal variation, suggesting that the associations held across a wide range of demographic and clinical subgroups.

Researchers concluded that unmarried individuals, particularly those who were divorced or never married, had a lower risk of developing dementia than those who remained married. These associations persisted even after adjusting for physical and mental health, lifestyle factors, genetics, and differences in clinical referral and evaluation.
Alzheimer's disease and Lewy body dementia were higher in married participants. Risk of progression from mild cognitive impairment to dementia was also higher.
The findings contrast with prior studies linking unmarried status to increased dementia risk and offer new evidence on how relationship status may relate to cognitive outcomes when diagnosis is measured under standardized conditions.

Selin Karakose et al, Marital status and risk of dementia over 18 years: Surprising findings from the National Alzheimer's Coordinating Center, Alzheimer's & Dementia (2025). DOI: 10.1002/alz.70072

Part 2

Comment by Dr. Krishna Kumari Challa on April 7, 2025 at 8:45am

Marriage linked to higher dementia risk in older adults, 18-year study finds

This one is going to surprise you.

Researchers found that older adults who were divorced or never married had a lower risk of developing dementia over an 18-year period compared to their married peers. Findings suggest that being unmarried may not increase vulnerability to cognitive decline, contrary to long-held beliefs in public health and aging research.

Marriage is often linked to better health outcomes and longer life, but evidence connecting marital status to dementia risk remains inconsistent. 

Prior research has not consistently addressed how marital status relates to specific causes of dementia or how factors such as sex, depression, or genetic predisposition may influence these associations.

In the study, "Marital status and risk of dementia over 18 years: Surprising findings from the National Alzheimer's Coordinating Center," published in Alzheimer's & Dementia, researchers conducted an 18-year cohort study to understand whether marital status was associated with dementia risk in older adults.

More than 24,000 participants without dementia at baseline were enrolled from over 42 Alzheimer's Disease Research Centers across the United States through the National Alzheimer's Coordinating Center. Annual clinical evaluations were conducted by trained clinicians using standardized protocols to assess cognitive function and determine diagnoses of dementia or mild cognitive impairment.

To assess long-term risk, researchers followed participants for up to 18.44 years, yielding over 122,000 person-years of data. Marital status at baseline was categorized as married, widowed, divorced, or never married.

Dementia risk was analyzed using Cox proportional hazards regression, with married participants serving as the reference group. The models incorporated demographic characteristics, mental and physical health, behavioral history, genetic risk factors, and diagnostic as well as enrollment variables.

Compared to married participants, divorced or never married showed a consistently lower risk of developing dementia over the study period. Dementia diagnoses occurred in 20.1% of the overall sample. Among married participants, 21.9% developed dementia during the study period. Incidence was identical among widowed participants at 21.9% but notably lower for divorced (12.8%) and never-married participants (12.4%).

Hazard ratios showed a reduced risk for all three unmarried groups. In initial models adjusting only for age and sex, divorced individuals had a 34% lower risk of developing dementia (HR = 0.66, 95% CI = 0.59–0.73), never-married individuals had a 40% lower risk (HR = 0.60, 95% CI = 0.52–0.71), and widowed individuals had a 27% lower risk (HR = 0.73, 95% CI = 0.67–0.79).

These associations remained significant for the divorced and never-married groups after accounting for health, behavioral, genetic, and referral-related factors. The association for widowed participants weakened and was no longer statistically significant in the fully adjusted model.
Part 1

Comment by Dr. Krishna Kumari Challa on April 7, 2025 at 8:34am

Scientists discover how nanoparticles of toxic metal used in MRI scans infiltrate human tissue

 Researchers studying the health risks posed by gadolinium, a toxic rare earth metal used in MRI scans, have found that oxalic acid, a molecule found in many foods, can generate nanoparticles of the metal in human tissues.

In a new paper published in the journal Magnetic Resonance Imaging, a research team  sought to explain the formation of the nanoparticles, which have been associated with serious health problems in the kidneys and other organs.

The worst disease caused by MRI contrast agents is nephrogenic systemic fibrosis. People have succumbed after just a single dose. The condition can cause a thickening and hardening of the skin, heart and lungs and cause painful contracture of the joints.

Gadolinium-based contrast agents are injected prior to MRI scans to help create sharper images.

The metal is usually tightly bound to other molecules and is excreted from the body, and most people experience no adverse effects. However, previous research has shown that even in those with no symptoms, gadolinium particles have been found in the kidney and the brain and can be detected in the blood and urine years after exposure.

Scientists are left with intertwined puzzles: Why do some people get sick, when most don't, and how do gadolinium particles become pried loose from the other molecules in the contrast agent?

Almost 50% of the patients had been exposed only a single time, which means that there's something that is amplifying the disease signal.

In their study, the research team focused on oxalic acid, which is found in many plant-based foods, including spinach, rhubarb, most nuts and berries and chocolate, because it binds with metal ions. The process helps lead to the formation of kidney stones, which result when oxalate binds with calcium. Meanwhile, oxalic acid also forms in the body when people eat foods or supplements containing vitamin C.

In test tube experiments the researchers found that oxalic acid caused minute amounts of gadolinium to precipitate out of the contrast agent and form nanoparticles, which then infiltrated the cells of various organs.

Some people might form these things, while others do not, and it may be their metabolic milieu. It might be if they were in a high oxalic state or a state where molecules are more prone to linking to the gadolinium, leading to the formation of the nanoparticles. That might be why some individuals have such awful symptoms and this massive disease response, whereas other people are fine.

The finding points to a possible way to mitigate some of the risks associated with MRI scan.

The scientists are getting closer to some recommendations for helping these individuals who are susceptible.

Ian M. Henderson et al, Precipitation of gadolinium from magnetic resonance imaging contrast agents may be the Brass tacks of toxicity, Magnetic Resonance Imaging (2025). DOI: 10.1016/j.mri.2025.110383

Comment by Dr. Krishna Kumari Challa on April 6, 2025 at 11:18am

Researchers identified curious DNA "dots" within infected cells under a light microscope. Professor Elizabeth Villa's laboratory then used high-end imaging technologies to discover that these dots were tiny vesicles containing viral DNA and molecular machineries outside these vesicles.
They found that these vesicles were actually metabolically active, confirming the purpose of the molecular machines hanging outside the vesicles.
Not only did the researchers show that these vesicles are making RNA, but also they are getting ready to establish infection by synthesizing genes important for nucleus formation.

Emily G. Armbruster et al, Sequential membrane- and protein-bound organelles compartmentalize genomes during phage infection, Cell Host & Microbe (2025). DOI: 10.1016/j.chom.2025.03.005

Part 2

Comment by Dr. Krishna Kumari Challa on April 6, 2025 at 11:16am

Jumbo phages infect cells with a protective cloaking mechanism, researchers discover

In a growing global trend, bacteria are evolving new ways to maneuver around medical treatments for a variety of infections. The rising antibiotic resistance crisis poses a significant public health threat in hospitals and other settings, with infections resulting in millions of deaths in recent years.

Scientists are now looking to bacteriophages—viruses that infect bacteria—and their potential to treat drug-resistant infections. They have begun to look deeper into an intriguing class of large bacteriophage known as "jumbo phages" that exhibit extraordinary features as possible new agents for bacterial infection treatments.

A study by  researchers has shed new light on the unusual ways that phages have evolved to infect bacteria. Over millions of years, viruses and bacteria have engaged in a back-and-forth arms race. Viruses develop new ways to infect bacteria, while bacteria counter by evolving a resistance mechanism.

In order to fully realize the potential of jumbo phages and their promise as new therapeutics, researchers must decipher the mechanisms they employ to infect bacteria and evade the host's defenses.

A new study published in the journal Cell Host & Microbe describes the first-of-its-kind discovery of a type of membrane-bound sac, or vesicle, used by jumbo phages of the Chimalliviridae family.

The researchers  found that immediately after jumbo phages infect a bacterial cell, they form a structure that shields and hides valuable DNA material. Phages use this genetic material to develop a nucleus inside their bacterial hosts.

The newly discovered compartment, which they named the EPI, or early phage infection vesicle, serves as a type of cloaking device that prevents triggering the bacteria's immune system.

When phages infect a bacterial cell, the EPI vesicle protects the genome of the virus during early stages of infection when it's very vulnerable. Bacteria and viruses are often dismissed as simple organisms but they're actually capable of very sophisticated intracellular warfare and this study is a new example of that.

Because most phages simply inject their DNA directly into the host, effectively announcing their arrival within the cell, the results of Chimalliviridae phage's stealth approach came as a revelation to researchers.  The bacteria don't realize that there's a virus in there, producing things that will eventually take over.

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