(Press-News.org) Scientists have known that toxic effects of substances known as endocrine disrupting chemicals (EDCs), found in both natural and human-made materials, can pass from one generation to the next, but new research shows that females with ancestral exposure to EDC may show especially adverse reactions to stress.
According to a new study by researchers from The University of Texas at Austin and Washington State University, male and female rats are affected differently by ancestral exposure to a common fungicide, vinclozolin. Female rats whose great grandparents were exposed to vinclozolin become much more vulnerable to stress, becoming more anxious and preferring the company of novel females to familiar females. Males who have the same combination of ancestral exposure and stress do not have the same adverse effects.
"These results should concern us all because we have been exposed to endocrine disrupting chemicals for decades and we all go through natural challenges in life," said David Crews, the Ashbel Smith Professor of Zoology and Psychology at The University of Texas at Austin and lead author of the study. "Those challenges are now being perceived differently because of this ancestral exposure to environmental contamination."
The study was published July 22 online in the journal Endocrinology.
Vinclozolin is a fungicide commonly used by farmers to treat fruits and vegetables.
To test the effects of stress on rats, the researchers confined some of them to soft, warm cylinders for six hours a day for three weeks. This was done during adolescence, a developmentally sensitive time of life for rats, just as for humans. Months later, the researchers tested the brain chemistry, brain function, gene expression and behavior of the rats as adults.
They discovered that for female rats, ancestral exposure to vinclozolin alone or stress during the animal's adolescence alone had negligible effects on the rats' hormonal balance and behavior. However, the combination of ancestral exposure and stress caused the female rats to have dramatically higher levels of corticosterone (a stress hormone similar to cortisol in humans), higher expression of genes associated with anxiety and more anxious behaviors. Other research has shown that stress hormones cause degeneration of a region of the brain associated with memory and learning.
Crews said that following exposure to EDCs, what is being passed down from generation to generation is not a change in the genetic code of the animals, but rather a change in the way specific genes are expressed. Gene expression is the process by which a cell uses the genetic code to make useful products such as proteins. If a section of a person's genetic code were a cookie recipe, gene expression would refer to how many cookies, if any, a cook makes with the recipe. The observation that changes in gene expression can be passed on to future generations has led to a new field of research known as epigenetics.
Crews and others have shown that EDCs can increase the risk in future generations for human illnesses such as autism, obesity and cardiovascular disease. Crews noted that environmental levels of EDCs are continuing to rise, as well as the rates of these diseases, particularly mental disorders.
INFORMATION:
Crews' co-authors are Ross Gillette, Isaac Miller-Crews and Andrea Gore of The University of Texas at Austin; and Eric Nilsson and Michael Skinner of Washington State University.
This work was supported by the National Science Foundation and the National Institutes of Health.
Download the paper "Sexually dimorphic effects of ancestral exposure to vinclozolin on stress reactivity in rats": http://press.endocrine.org/doi/abs/10.1210/en.2014-1253
Exposure to toxins makes great granddaughters more susceptible to stress
2014-08-25
[Attachments] See images for this press release:
ELSE PRESS RELEASES FROM THIS DATE:
MU researchers discover protein's ability to inhibit HIV release
2014-08-25
COLUMBIA, Mo. — A family of proteins that promotes virus entry into cells also has the ability to block the release of HIV and other viruses, University of Missouri researchers have found.
"This is a surprising finding that provides new insights into our understanding of not only HIV infection, but also that of Ebola and other viruses," said Shan-Lu Liu, M.D., Ph.D., associate professor in the MU School of Medicine's Department of Molecular Microbiology and Immunology.
The study was recently published in the Proceedings of the National Academy of Sciences. Liu, the ...
Cancer-fighting drugs might also stop malaria early
2014-08-25
DURHAM, N.C. -- Scientists searching for new drugs to fight malaria have identified a number of compounds -- some of which are currently in clinical trials to treat cancer -- that could add to the anti-malarial arsenal.
Duke University assistant professor Emily Derbyshire and colleagues identified more than 30 enzyme-blocking molecules, called protein kinase inhibitors, that curb malaria before symptoms start.
By focusing on treatments that act early, before a person is infected and feels sick, the researchers hope to give malaria –- especially drug-resistant strains ...
Sweet! Glycoconjugates are more than the sum of their sugars
2014-08-25
There's a certain type of biomolecule built like a nano-Christmas tree. Called a glycoconjugate, it's many branches are bedecked with sugary ornaments.
It's those ornaments that get all the glory. That's because, according to conventional wisdom, the glycoconjugate's lowly "tree" basically holds the sugars in place as they do the important work of reacting with other molecules.
Now a chemist at Michigan Technological University has discovered that the tree itself—called the scaffold—is a good deal more than a simple prop.
"We had always thought that all the biological ...
Doctors miss opportunities to offer flu shots
2014-08-25
Doctors should make a point of offering a flu vaccine to their patients. A simple reminder could considerably reduce the number of racial and ethnic minorities who currently do not vaccinate themselves against this common contagious respiratory illness. This recommendation is based on research led by Jürgen Maurer of the University of Lausanne in Switzerland and the RAND Corporation in the US. Their findings¹ are published in the Journal of General Internal Medicine², published by Springer.
Up to 50,000 Americans die annually of influenza and related diseases such as ...
New coping strategy for the memory impaired and their caregivers
2014-08-25
CHICAGO --- Mindfulness training for individuals with early-stage dementia and their caregivers together in the same class was beneficial for both groups, easing depression and improving sleep and quality of life, reports new Northwestern Medicine study.
"The disease is challenging for the affected person, family members and caregivers," said study lead author Ken Paller, professor of psychology at Weinberg College of Arts and Sciences at Northwestern and a fellow of the Cognitive Neurology and Alzheimer's Disease Center at Northwestern University Feinberg School of ...
To deter cyberattacks, build a public-private partnership
2014-08-25
CHAMPAIGN, Ill. — Cyberattacks loom as an increasingly dire threat to privacy, national security and the global economy, and the best way to blunt their impact may be a public-private partnership between government and business, researchers say. But the time to act is now, rather than in the wake of a crisis, says a University of Illinois expert in law and technology.
According to a study by Jay Kesan, the H. Ross and Helen Workman Research Scholar at the College of Law, an information-sharing framework is necessary to combat cybersecurity threats.
"Cybersecurity is ...
Learning by watching, toddlers show intuitive understanding of probability
2014-08-25
Most people know children learn many skills simply by watching people around them. Without explicit instructions youngsters know to do things like press a button to operate the television and twist a knob to open a door. Now researchers have taken this further, finding that children as young as age 2 intuitively use mathematical concepts such as probability to help make sense of the world around them.
In a study led by researchers at the University of Washington, toddlers could tell the difference between two different ways an experimenter played a game, with one strategy ...
Fires above the Great Slave Lake in Canada
2014-08-25
Updates from NWTfire.com report that there are 133 active fires in the North Slave Region of the Northwest Territories. No new fires reported in the past 24 hours. Fire danger is moderate to high. Smoke may be an issue in some communities.
The Birch Lake Complex of fires are in an area approximately 80 km south of Behchoko and extending to within 30 km north of Fort Providence. Four crews will be working on hot spots and mopping up at Moraine Point this week. Mop-up continues many areas of complex's fire perimeter. The total fire complex area is estimated at 650,000 ...
Zombie ant fungi 'know' brains of their hosts
2014-08-25
A parasitic fungus that reproduces by manipulating the behavior of ants emits a cocktail of behavior-controlling chemicals when encountering the brain of its natural target host, but not when infecting other ant species, a new study shows.
The findings, which suggest that the fungus "knows" its preferred host, provide new insights into the molecular mechanisms underlying this phenomenon, according to researchers.
"Fungi are well known for their ability to secrete chemicals that affect their environment," noted lead author Charissa de Bekker, a Marie Curie Fellow in ...
Sweet! Glycocongugates are more than the sum of their sugars
2014-08-25
There's a certain type of biomolecule built like a nano-Christmas tree. Called a glycoconjugate, it's many branches are bedecked with sugary ornaments.
It's those ornaments that get all the glory. That's because, according to conventional wisdom, the glycoconjugate's lowly "tree" basically holds the sugars in place as they do the important work of reacting with other molecules.
Now a chemist at Michigan Technological University has discovered that the tree itself—called the scaffold—is a good deal more than a simple prop.
"We had always thought that all the biological ...