Sunday, March 30, 2025

Global patterns in seed plant distribution over millions of years

International research team investigates how environment and barriers to dispersal shape biodiversity

University of Göttingen

image:
The interplay of environmental conditions and geographical barriers such as mountains and lakes determine where plants thrive – an international study shows how these patterns have developed over millions of years.
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Credit: Holger Kreft

Why do some plants thrive in specific regions but not in others? A study led by researchers at the University of Göttingen explores the factors shaping plant distributions and how these patterns have changed over millions of years. Analyzing nearly 270,000 seed plant species worldwide, the research highlights the roles of environmental conditions and dispersal barriers in influencing global plant diversity. The results were published in Nature Ecology & Evolution.

Using advanced methods that integrate plant distributions with phylogenetic information – meaning data about the evolutionary relationships among plant species – researchers combined modern environmental data with historical reconstructions of Earth’s climate and geography spanning millions of years. The team examined how variations in climate, soil, and other environmental factors determine where plants can thrive and how physical barriers – such as oceans, mountain ranges, and areas with inhospitable climates – restrict plant dispersal.

The findings show that environmental conditions, particularly climate, are important factors in shaping plant distributions, with their influence remaining consistent across evolutionary timescales. Physical barriers like oceans and mountains played a significant role in limiting the spread of more recently evolved plant groups but had a much smaller effect on ancient plant groups, which have had longer periods to disperse widely. Past tectonic plate positions and movements, reconstructed from geological data, were found to have only a modest impact on plant diversity, with their strongest effects occurring between 20 and 50 million years ago.

“These findings reveal a fundamental process in nature,” says Dr Lirong Cai from the University of Göttingen and the German Centre for Integrative Biodiversity Research (iDiv). “Given enough time, plants can overcome the barriers of vast distances and geography, but they often remain limited by the environments they encounter.”

Original publication: Cai, L., et al. (2024). Environmental filtering, not dispersal history, explains global patterns of phylogenetic turnover in seed plants at deep evolutionary timescales. Nature Ecology and Evolution. DOI: 10.1038/s41559-024-02599-y

The research showed that with enough time, plants can overcome the barriers of vast distances and geography, but they often remain limited by the environments they encounter.

Credit

Holger Kreft

Contact:

Professor Holger Kreft

University of Göttingen

Biodiversity, Macroecology and Biogeography Research Group

Büsgenweg 1, 37077 Göttingen, Germany

Email: hkreft@uni-goettingen.de

www.uni-goettingen.de/en/128741.html

Journal

Nature Ecology & Evolution

DOI

10.1038/s41559-024-02599-y

Method of Research

Observational study

Subject of Research

Not applicable

Article Title

Environmental filtering, not dispersal history, explains global patterns of phylogenetic turnover in seed plants at deep evolutionary timescales

OF MICE AND MEN

Intermittent fasting increases sex drive in male mice: an approach for low libido in humans?

Current findings could point the way for new therapy option / Serotonin plays key role

DZNE - German Center for Neurodegenerative Diseases

Long-term fasting in 24-hour cycles increases the sex drive of male mice by lowering the concentration of the neurotransmitter serotonin in the brain. This effect is linked to a diet-induced deficiency of the precursor substance tryptophan – an amino acid that must be obtained through food. Researchers from DZNE report on this in the journal Cell Metabolism, together with a Chinese team from Qingdao University and the University of Health and Rehabilitation Sciences. They suggest that similar mechanisms may exist in humans and view fasting as a potential approach for treating unwanted loss of sexual desire.

Fasting is a recurring subject of research because reduced food intake and thus calorie restriction has a variety of effects on the organism beyond the commonly observed weight loss. Dr. Dan Ehninger, research group leader at DZNE and lead author of the current study, and his team have also been working on this topic for quite some time. “We are interested in the effects of fasting on aging. Using mice as a model, we investigate the underlying biological mechanisms. Our aim is to gain insights that may also be relevant to humans,” says the Bonn-based scientist.

More offspring than expected

The research results now published are based on a fortuitous discovery, as Ehninger and his colleagues had originally set out to investigate something else. Their aim was to examine how fasting affects the offspring of male mice. However, one particular finding steered their research in a new direction: aged male mice – senior individuals by human standards – that had fasted for extended periods produced an unusually large number of offspring. Contrary to initial hypotheses, this phenomenon was not due to fasting effects on reproductive organs or the endocrine state of the animals. Age-related changes in the testes, reduced sperm quality and lower testosterone levels, for example, argued against high fertility. “It was a bit of detective work to uncover the real cause,” says Ehninger, whose research group collaborated on the current study with experts from Qingdao University and the University of Health and Rehabilitation Sciences led by Prof. Yu Zhou. “Eventually, we realized: it is a matter of behavior. The fasting males had significantly more sexual contacts than mice that could eat freely. In other words, these animals had an unusually high frequency of mating and, as a result, an unusually high number of offspring for their age. Their mating behavior more than compensated for the age-related physiological limitations.”

Fasting in a 24-hour rhythm

Starting at two months of age, these male mice were subjected to a specific form of intermittent fasting. Their access to food followed a recurring 24-hour pattern: the animals were allowed to feed ad libitum for 24 hours, followed by 24 hours with access to water only. During the 22-month fasting regimen, the males were housed together without any contact with females. They were later introduced to three-month-old females that had been raised without dietary restrictions.

Effect takes time

Increased mating behavior was also observed in younger mice. These males had also started intermittent fasting at the age of two months, but had followed this diet for only six months before being introduced to females. They, too, were more sexually active than age-matched peers that had been fed ad libitum. However, the effect was absent in other experimental groups – both young and old – that fasted for only a few weeks. “For intermittent fasting to increase sex drive, it takes some time,” says Zhou. “Based on our experiments, the minimum duration appears to be somewhere between six weeks and six months.”

A question of serotonin

In the course of investigating the causes, the attention eventually turned to neurotransmitters that influence sexual behavior. Some have a stimulating effect, while others act as inhibitors. Among the sexually active male mice, one factor stood out: serotonin – a chemical messenger generally associated with inhibitory effects – was present at unusually low levels. “These mice were, so to speak, sexually uninhibited, the usual regulatory restraint was diminished,” says Ehninger. Serotonin is primarily produced in the gastrointestinal tract, but also in the brain, where it acts as a neurotransmitter mediating communication between neurons. However, its synthesis depends on the amino acid tryptophan, which must be obtained through the diet or released through the breakdown of the body’s own protein stores, such as those found in muscle tissue. Tryptophan is considered an essential amino acid, meaning that neither mice nor humans can synthesize it on their own. As a result, dietary intake plays a key role in regulating tryptophan levels in the body. It is, in fact, found in many common foods. “The lack of serotonin was clearly a result of fasting,” explains the DZNE researcher.

Is the fasting regimen relevant?

“All in all, the fasting mice consumed almost fifteen percent fewer calories than the animals in the control group. This also roughly applies to their intake of tryptophan,” says Zhou. “However, it is currently unclear whether the reduction in serotonin levels is linked to our specific feeding regimen or would also occur with other types of fasting. Future studies will need to clarify this.” As the scientist notes, it is also possible that the effect could occur under a general caloric restriction, where food is continuously available but in reduced amounts.

A potential approach for therapy

“Chemical messengers also play an important role in regulating sexual behavior in humans. This applies in particular to serotonin,” says Ehninger. As he points out, this is evident, for example, in the use of SSRIs, a class of antidepressant drugs that increase serotonin levels. A potential side effect of this therapy is reduced libido. Conversely, lower serotonin levels are known to promote sexual desire. “In view of this, I consider it very plausible that sexual desire in humans can be influenced by fasting – possibly not only in men, but also in women, since serotonin affects their libido as well.” According to Ehninger, there are actually only a few scientific studies on the effects of fasting on human libido. “In my opinion, it would make sense to investigate this in more detail. I see potential for therapeutic application. A lack of sexual desire is not necessarily perceived as problematic – but some people suffer from it. This condition is known as ‘hypoactive sexual desire disorder’ and particularly affects older adults. Fasting could potentially serve as a useful addition to existing treatment options.”

About Deutsches Zentrum für Neurodegenerative Erkrankungen, DZNE (German Center for Neurodegenerative Diseases): DZNE is one of the world’s leading research centers for neurodegenerative diseases such as Alzheimer’s, Parkinson’s and ALS, which are associated with dementia, movement disorders and other serious health impairments. These diseases place an enormous burden on patients and their families, but also on society and the economy of healthcare. DZNE contributes significantly to the development and translation into practice of novel strategies for prevention, diagnosis, care and treatment. DZNE comprises ten sites across Germany and collaborates with universities, university hospitals, research centers and other institutions in Germany and throughout the world. DZNE is state-funded and a member of the Helmholtz Association and of the German Centers for Health Research. www.dzne.de/en

Journal

Cell Metabolism

DOI

10.1016/j.cmet.2025.03.001

Method of Research

Experimental study

Subject of Research

Animals

Article Title

Intermittent fasting boosts sexual behavior by limiting the central availability of tryptophan and serotonin

Article Publication Date

28-Mar-2025

Discrimination-related depression, anxiety pronounced among multiracial, White, Asian populations

Boston University School of Public Health

A new study found that more than half of US adults encounter some form of discrimination, and that this mistreatment may fuel higher chances of depression and/or anxiety among specific racial and ethnic groups due to cultural, social, and systemic factors.

A growing body of research has drawn connections between everyday discrimination—the routine and often subtle forms of mistreatment that people experience on a day-to-day basis—and poor mental health. A new study by Boston University School of Public Health (BUSPH) and Brown University suggests that higher exposure to discrimination increases a person’s chances of developing depression and/or anxiety, and that this outcome varies by race and ethnicity.

Published in JAMA Network Open, the study found that over half of US adults experienced some form of discrimination, and individuals with high exposure to discrimination have more than five times the chances of screening positive for depression, and five times the chances of screening positive for anxiety. Compared to adults who do not experience discrimination, adults who do experience this mistreatment have nearly nine times the odds of screening positive for both depression and anxiety.

These observations were similar for men and women, but more pronounced among multiracial, White, and Asian adults, populations that are often overlooked in research and discussions about the effect of discrimination on health.

The nationally representative findings provide valuable insight into the relationship between discrimination and mental health among multiple populations, building upon previous research on this subject that has been restricted by smaller study groups or limited comparisons between Black and White populations, or Hispanic or Latino and non-Hispanic or non-Latino populations. The researchers hope this data provides a deeper understanding of the mental health consequences of discrimination among a wider range of demographic groups, and encourages mental health screenings and support to mitigate these racial disparities.

“Our study expands our understanding beyond typical Black-White comparisons, showing that everyday discrimination is a widespread issue that negatively impacts mental health across all racial and ethnic groups,” says study lead and corresponding author Dr. Monica Wang, associate professor of community health sciences at BUSPH.

For the study, Dr. Wang and study senior author Dr. Marie-Rachelle Narcisse, assistant professor of psychiatry and human behavior at Brown, assessed 2023 national survey data to gauge experiences of discrimination, depression, and anxiety among nearly 30,000 adults ages 18 or older. This sample population was weighted to represent more than 258 million US adults. To measure discrimination, the researchers utilized standardized scales that capture the frequency of mistreatment, such as receiving poor service or being harassed. They also utilized standardized scales to quantify experiences with depression (such as feeling down or hopeless, or having little interest in doing things) and anxiety (such as feeling nervous or experiencing an inability to stop worrying).

Nearly 56 percent of adults experienced a form of discrimination, and 3.6 percent of this group reported experiencing high levels of discrimination, most prevalent among Black adults, followed by multiracial or other adults, Hispanic or Latino adults, White adults, and Asian adults. Discrimination was also more common among adults experiencing certain health disadvantages such as disabilities, obesity, and food insecurity, as well as immigrants and women.

The researchers theorize that a combination of social, cultural, and systemic factors may be driving discrimination-related depression or anxiety among specific racial and ethnic groups. Multiracial individuals may navigate unique experiences of mistreatment based on their multiple racial identities, while White individuals may experience mental health challenges that stem from mistreatment related to their income or educational levels. Asian adults may experience depression or anxiety stemming from language barriers or the “model minority” stereotype, which assumes all Asian individuals are high-achieving and successful.

These perceived experiences carry real psychological weight, says Dr. Narcisse.

“Studies have shown that discrimination shapes mental health most deeply when left unacknowledged,” she says. I hope this study creates more awareness. As in awareness, there is strength and the ability to seek healing more intentionally.”

Dr. Wang and Dr. Narcisse also caution that these findings do not suggest that discriminatory experiences and any related adverse mental health problems are less significant among Black, Hispanic, and Latino populations, as these groups continue to experience multiple health challenges driven by systemic racism and a long history of oppression.

“Our results are a powerful reminder that discrimination is everyone’s issue—and addressing it benefits society as a whole,” Dr. Wang says.

Dr. Wang is supported in part by the National Institute of Diabetes and Digestive and Kidney Diseases; Dr. Narcisse is supported by the National Institute of General Medical Sciences and the Bradley Hospital COBRE Center for Sleep and Circadian Rhythms in Child and Adolescent Mental Health. The funding sources had no role in the design or conduct of the study; collection, analysis, and interpretation of data; preparation, review, or approval of the manuscript. The content is solely the responsibility of the authors and does not necessarily represent the official views of the funders.

About Boston University School of Public Health

Founded in 1976, Boston University School of Public Health is one of the top ten ranked schools of public health in the world. It offers master's- and doctoral-level education in public health. The faculty in six departments conduct policy-changing public health research around the world, with the mission of improving the health of populations—especially the disadvantaged, underserved, and vulnerable—locally and globally.

Journal

JAMA Network Open

DOI

10.1001/jamanetworkopen.2025.2404

Method of Research

Observational study

Subject of Research

People

Article Title

Discrimination, Depression, and Anxiety Among US Adults

Article Publication Date

28-Mar-2025

Endocrine Society statement on HHS restructuring, mass firings, and scientific review

The Endocrine Society

WASHINGTON—A major reorganization of the U.S. Department of Health and Human Services (HHS)—including massive cuts to the federal workforce—threatens scientific progress that drives our economy and improves the public’s health.

Slashing federal funding and staff will hobble the very agencies that fuel medical discoveries and approve new treatments.

In addition, the administration is introducing a new level of administrative review of grants at the National Institutes of Health (NIH) that will politicize the process of awarding scientific grants.

These actions reflect a disregard for congressional appropriations and authorizing processes as well as stakeholder experience, and will allow politicians, not scientific experts, to set research priorities.

The Endocrine Society is concerned actions of this scale will hinder HHS’s important public health functions and research related to chronic diseases like diabetes and obesity and other endocrine conditions, including thyroid disease, osteoporosis, infertility, endocrine cancers, and growth disorders.

After recent efforts to freeze and rescind federal funding, the Endocrine Society worries the plan to reorganize HHS is another example of the administration unilaterally deciding not to spend funds that Congress lawfully appropriated. It is not clear that consideration was given to the impact on programs with proven records of protecting the public’s health.

Laying off 1,200 NIH staff members will affect the agency’s ability to fulfill its research responsibilities and slow advancements in endocrine science and other fields. Reduced staffing will impede the NIH’s ability to review grant applications, fund research and run needed programs.

Biomedical research performed at and supported by the NIH is responsible for improving the public health of millions of Americans and people around the world. The loss of staff will leave a gap of knowledge, institutional history, and expertise that will damage the research landscape.

The Society also is alarmed by media reports that NIH research grants will be reviewed by HHS and the Department of Government Efficiency (DOGE). Research funding decisions should be made based on scientific merit and public health priorities, not the politics of the day. Introducing political influence into the research process creates an environment where scientists cannot rely on consistent, stable funding sources.

Impeding scientific research and the development of new treatments will ultimately harm millions of people who need medical care for endocrine conditions.

The Endocrine Society calls on the administration to work with Congress and the health and research communities to improve the efficiency of health-related agencies in a transparent, thoughtful manner. The current unilateral approach risks harm to the public’s health and research enterprise.

# # #

Endocrinologists are at the core of solving the most pressing health problems of our time, from diabetes and obesity to infertility, bone health, and hormone-related cancers. The Endocrine Society is the world’s oldest and largest organization of scientists devoted to hormone research and physicians who care for people with hormone-related conditions.

The Society has more than 18,000 members, including scientists, physicians, educators, nurses and students in 122 countries. To learn more about the Society and the field of endocrinology, visit our site at www.endocrine.org. Follow us on Twitter at @TheEndoSociety and @EndoMedia.

Auburn and FIOCRUZ tackle the rising global challenge of Chagas Disease

Advanced computational simulations offer new perspectives on Chagas Disease mechanisms: A groundbreaking approach to visualizing parasite-host interactions at the molecular level\

Auburn University Department of Physics

Pioneering Research Team — image:
From left to right, Dr. Manuela Leal da Silva, Ms. Raissa Rosa, and Dr. Rafael C. Bernardi, the collaborative team of researchers from Auburn University and FIOCRUZ who are advancing our understanding of Chagas Disease through groundbreaking molecular dynamics simulations.
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Credit: Auburn Physics

Auburn, AL – Researchers from Auburn University, in a landmark collaboration with Brazil's Oswaldo Cruz Foundation (FIOCRUZ), the world's leading research institution on Chagas Disease, have published a significant study in the journal Biochemistry. The study sheds new light on how the Chagas Disease parasite invades human cells—a crucial step towards developing effective treatments for this neglected tropical disease.

Chagas Disease, caused by the parasite Trypanosoma cruzi, is traditionally endemic to Latin America but is increasingly becoming a global health concern. "With international travel and migration pushing the disease beyond its original borders, it’s becoming a silent threat in regions like the US and Europe where it often goes unrecognized due to non-specific early symptoms," says Dr. Bernardi, lead researcher at Auburn University.

The collaborative research utilized a novel molecular dynamics simulation to examine the interaction between the parasite’s protein gp82 and the human receptor LAMP2. This interaction is pivotal for the parasite's entry into human cells. The study, the first to model this interaction at such an atomic detail, identifies new potential targets for therapeutic intervention which could lead to the development of drugs to block the infection process.

"This research is not just about scientific discovery," emphasizes Dr. Bernardi. "It’s about addressing a major, yet neglected global health issue. Chagas Disease affects millions and poses a significant burden on public health systems, particularly in Latin America. However, its spread to the US and Europe—where data on its prevalence remains scarce—highlights the urgent need for increased surveillance and research."

FIOCRUZ's partnership in this study underscores the global imperative to combat Chagas Disease. "Collaborating with Auburn University allows us to blend cutting-edge technology with decades of expertise in Chagas research," says Dr. Leal da Silva, co-author and a professor at both FIOCRUZ and Universidade Federal do Rio de Janeiro. "This study is a critical step toward a more comprehensive understanding of the molecular mechanisms of Chagas Disease, which is essential for the development of effective treatments."

Raissa Rosa, a graduate student at both FIOCRUZ and Auburn University, adds, "This collaboration has been incredibly enlightening. It allowed us to connect known experimental results with computational work that enabled us to visualize the interaction at the atomistic level. We were able to see things that not only explain the experimental results but also go beyond, revealing new aspects of the parasite-host interaction that we could never see before."

The study also highlights the potential for international research collaborations to tackle complex health challenges. "Chagas Disease has been neglected for far too long," Dr. Bernardi adds. "But with the combined efforts of institutions like Auburn and FIOCRUZ, we are making significant strides in understanding and eventually mitigating this disease."

Auburn University's Biophysics cluster, a collaborative initiative within the College of Sciences and Mathematics (COSAM), brings together faculty from the Departments of Biological Sciences, Physics, and Chemistry & Biochemistry. This interdisciplinary group is dedicated to advancing the frontiers of biophysics by integrating diverse scientific disciplines to address complex biological problems. Through innovative research and education, the cluster contributes significantly to our understanding of fundamental biological processes and diseases, such as Chagas Disease, highlighting Auburn's commitment to pushing the boundaries of science and health.

This map, produced with 2018 World Health Organization data, highlights the reported cases of Chagas Disease. While traditionally associated with Latin America, the disease has spread, silently invading new regions around the world. Note: Data covers only a limited portion of the globe, indicating underreporting and the potential for a significantly wider impact.

Credit

Raissa Rosa - Auburn University

This rendering illustrates the critical interaction between gp82 on the Trypanosoma cruzi parasite and LAMP2 on the human cell membrane. The proximity of the two membranes, shown here, is a crucial step in the parasite's internalization process, enabling T. cruzi to invade and infect human cells.

Credit

Rafael C. Bernardi - Auburn University

Journal

Biochemistry

DOI

10.1021/acs.biochem.4c00710

Method of Research

Computational simulation/modeling

Subject of Research

Not applicable

Article Title

Atomistic Insights into gp82 Binding: A Microsecond, Million-Atom Exploration of Trypanosoma cruzi Host-Cell Invasion

Article Publication Date

28-Mar-2025

Navigating a US bioscience career despite anticipated cuts in funding for biomedicine

PLOS

Many young and midcareer scientists in the U.S. are understandably anxious about potential cuts to government funding and the rise of junk science. Although your future in biomedicine may not be what you originally planned, it might actually become more interesting and filled with new possibilities and opportunities for innovation. Don’t think of this time to hunker down and disappear. Do the opposite with the understanding that you are more powerful and brilliant than you may realize.

In your coverage, please use this URL to provide access to the freely available paper in PLOS Biology: https://plos.io/4bF93zK

Article title: Navigating your US bioscience career into the 2030s

Author countries: United States

Funding: The author received no specific funding for this work.

Journal

PLOS Biology

DOI

10.1371/journal.pbio.3003089

Method of Research

Commentary/editorial

LA REVUE GAUCHE - Left Comment

Sunday, March 30, 2025

Global patterns in seed plant distribution over millions of years

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DOI

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Article Title

Intermittent fasting increases sex drive in male mice: an approach for low libido in humans?

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Article Publication Date

Discrimination-related depression, anxiety pronounced among multiracial, White, Asian populations

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Article Publication Date

Endocrine Society statement on HHS restructuring, mass firings, and scientific review

Auburn and FIOCRUZ tackle the rising global challenge of Chagas Disease

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Credit

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DOI

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Subject of Research

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Article Publication Date

Navigating a US bioscience career despite anticipated cuts in funding for biomedicine

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