Nav: Home

In roundworms, fats tip the scales of fertility

April 20, 2017

Proper nutrition can unleash amazing powers, moms have always assured us, frequently citing Popeye the Sailor Man as evidence. Now, two University of Colorado Boulder scientists have confirmed just how potent some nutrients can be.

In findings published today in the journal Cell, postdoctoral fellow Hongyun Tang and Professor Min Han, both of CU Boulder's Department of Molecular, Cellular and Developmental Biology and the Howard Hughes Medical Institute, detail how fat levels in a tiny soil-dwelling roundworm (C. elegans) can tip the balance between whether the worm makes eggs or sperm.

Although the researchers discovered this phenomenon in worms, the research could have implications for future studies into human fertility and reproductive development.

Scientists have long recognized a connection between dietary fat and reproductive development in mammals, including humans.

"Studies in humans and rats have suggested that a high-fat diet is a major cause of early puberty in girls," said Han, the senior author of the paper. "It makes sense from an evolutionary standpoint that reproductive success would be coupled to food availability."

However, Han said, scientists understand surprisingly little about just how fat levels might be translated into fertility.

C. elegans comes in two sexes: males and hermaphrodites. Males produce sperm throughout their reproductive lives while hermaphrodites produce sperm only during a brief period, and later switch gears to making eggs.

Through a meticulous series of experiments, Tang homed in on one nutrient, a fatty acid called myristic acid, whose abundance, it turns out, worms can "monitor" using an enzyme called acyl-CoA synthase 4 (ACS-4). Fatty acids are chemical building blocks of dietary fats, so their level in a worm's body is one measure of the general nutritional quality of their food.

Tang found that the levels of certain fatty acids, including myristic acid, can influence the switch from sperm to egg production. When Tang depleted a particular myristic acid derivative from the germ cells in hermaphrodite worms by blocking the action of ACS-4, the worms never made the switch to making eggs.

Typically, a worm's sex-determination -- in this case, making eggs or sperm -- comes down to counting chromosomes. Hermaphrodites' cells have two sex chromosomes while males have only one. Tang, however, discovered that the worm's sex-determination system could also tap into information gathered by monitoring fatty acid levels.

But before the fatty acid can become tethered to the protein, it must be temporarily hitched to a molecule called CoA. ACS-4 is the enzyme that links myristic acid to CoA.

Tang found that the worms' sex-determination system can be overruled by the levels of myristoyl-CoA and myristoylated proteins. He determined that one component of the sex-determination system, a protein called MAP kinase, proved to be the link between the fatty acid monitoring and the switch from production of sperm to eggs.

This fatty-acid sensing phenomenon does not appear to be particular to hermaphroditic nematode species like C. elegans. When Tang partially blocked ACS-4 in females of a conventional male/female nematode species, many of the females made sperm instead of eggs.

The researchers call this newly-discovered ACS-mediated mechanism a "lipid sensor" and believe it could be a widespread strategy by which animals translate cues from the environment into physiological responses. The key proteins at work in the nematodes have highly similar counterparts in humans, suggesting that similar regulatory pathways may operate in people.
-end-
The work was supported by the Howard Hughes Medical Institute.

University of Colorado at Boulder

Related Fertility Articles:

A new way to assess male fertility
Current tests for male fertility include measuring the concentration and motility of spermatozoa.
Male fertility after chemotherapy: New questions raised
Professor Delbès, who specializes in reproductive toxicology, conducted a pilot study in collaboration with oncologists and fertility specialists from the McGill University Health Centre (MUHC) on a cohort of 13 patients, all survivors of pediatric leukemia and lymphoma.
Vaping may harm fertility in young women
E-cigarette usage may impair fertility and pregnancy outcomes, according to a mouse study published in the Journal of the Endocrine Society.
Are fertility apps useful?
Researchers at EPFL and Stanford have carried out an analysis of the largest datasets from fertility awareness apps.
Marijuana and fertility: Five things to know
For patients who smoke marijuana and their physicians, 'Five things to know about ... marijuana and fertility' provides useful information for people who may want to conceive.
How could a changing climate affect human fertility?
Human adaptation to climate change may include changes in fertility, according to a new study by an international group of researchers.
Migrants face a trade-off between status and fertility
Researchers from the universities of Helsinki, Turku and Missouri as well as the Family Federation of Finland present the first results from a new, extraordinarily comprehensive population-wide dataset that details the lives of over 160,000 World War II evacuees in terms of integration.
Phthalates may impair fertility in female mice
A phthalate found in many plastic and personal care products may decrease fertility in female mice, a new study found.
Climate change damaging male fertility
Climate change could pose a threat to male fertility -- according to new research from the University of East Anglia.
New test measures men's fertility
At a time when more than half of male infertility cannot be explained by current methods, a new test developed by Androvia LifeSciences is able to measure male fertility.
More Fertility News and Fertility Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Teaching For Better Humans 2.0
More than test scores or good grades–what do kids need for the future? This hour, TED speakers explore how to help children grow into better humans, both during and after this time of crisis. Guests include educators Richard Culatta and Liz Kleinrock, psychologist Thomas Curran, and writer Jacqueline Woodson.
Now Playing: Science for the People

#556 The Power of Friendship
It's 2020 and times are tough. Maybe some of us are learning about social distancing the hard way. Maybe we just are all a little anxious. No matter what, we could probably use a friend. But what is a friend, exactly? And why do we need them so much? This week host Bethany Brookshire speaks with Lydia Denworth, author of the new book "Friendship: The Evolution, Biology, and Extraordinary Power of Life's Fundamental Bond". This episode is hosted by Bethany Brookshire, science writer from Science News.
Now Playing: Radiolab

Dispatch 3: Shared Immunity
More than a million people have caught Covid-19, and tens of thousands have died. But thousands more have survived and recovered. A week or so ago (aka, what feels like ten years in corona time) producer Molly Webster learned that many of those survivors possess a kind of superpower: antibodies trained to fight the virus. Not only that, they might be able to pass this power on to the people who are sick with corona, and still in the fight. Today we have the story of an experimental treatment that's popping up all over the country: convalescent plasma transfusion, a century-old procedure that some say may become one of our best weapons against this devastating, new disease.   If you have recovered from Covid-19 and want to donate plasma, national and local donation registries are gearing up to collect blood.  To sign up with the American Red Cross, a national organization that works in local communities, head here.  To find out more about the The National COVID-19 Convalescent Plasma Project, which we spoke about in our episode, including information on clinical trials or plasma donation projects in your community, go here.  And if you are in the greater New York City area, and want to donate convalescent plasma, head over to the New York Blood Center to sign up. Or, register with specific NYC hospitals here.   If you are sick with Covid-19, and are interested in participating in a clinical trial, or are looking for a plasma donor match, check in with your local hospital, university, or blood center for more; you can also find more information on trials at The National COVID-19 Convalescent Plasma Project. And lastly, Tatiana Prowell's tweet that tipped us off is here. This episode was reported by Molly Webster and produced by Pat Walters. Special thanks to Drs. Evan Bloch and Tim Byun, as well as the Albert Einstein College of Medicine.  Support Radiolab today at Radiolab.org/donate.