PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Mating is the kiss of death for certain female worms

2013-12-20
(Press-News.org) Contact information: Catherine Zandonella
czandone@princeton.edu
Princeton University
Mating is the kiss of death for certain female worms

The presence of male sperm and seminal fluid causes female worms to shrivel and die after giving birth, Princeton University researchers reported this week in the journal Science. The demise of the female appears to benefit the male worm by removing her from the mating pool for other males.

The researchers found that male sperm and seminal fluid trigger pathways that cause females to dehydrate, prematurely age and die.

"Their lifespans are cut by about a third to a half," said senior author Coleen Murphy, an associate professor of molecular biology and the Lewis-Sigler Institute for Integrative Genomics.

The death of the female after she gives birth fits into a general framework of sperm competition that has been observed often in nature, said Murphy. "Males compete to have their genomes propagated, and this often occurs at the expense of the female."

Shortened female lifespans following mating have been observed before for roundworms, but the study is the first to document the body shrinkage and identify the underlying biological pathways, Murphy said.

"The fact that sex essentially kills the mothers after they have produced the males' progeny has never been reported before and is shocking to most people who hear this story for the first time, including researchers who study these worms," Murphy said.

The team found that the pathways by which the male kills the female are ones that researchers think exist for the purpose of slowing down aging during times of low nutrients.

"The males are taking these pathways and running them in reverse, causing the acceleration of aging and death," Murphy said.

The researchers discovered the effect in the Caenorhabditis elegans (C. elegans) roundworm, which is found in soil and rotting fruit and is about the size of a piece of lint. The roundworm is commonly used in research because many of its genetic pathways are similar to those of humans.

"That these pathways can be hijacked and run in reverse in a simple organism might suggest that that could also happen in more complex organisms," said Murphy. "So the work can help us understand male-female interactions and how they influence female longevity and reproduction."

Normally the females of the species C. elegans have no need for males, Murphy explained, because they are hermaphrodites — their bodies contain both sperm and egg cells so they can reproduce without coming in contact with males.

"The hermaphrodites try to avoid the males — they will try to sprint away from them. The males have to hunt them down to get them to mate," said Murphy.

Males, however, require females if they are to pass on their genes to future generations. Once inseminated, the female can give birth to hundreds of progeny, and these offspring do not require maternal care after they are born. Killing off the mother makes her unavailable to mate with other males, giving a genetic advantage to the father.

Graduate student Cheng Shi, lead author on the paper, discovered the effect unexpectedly while carrying out studies to look at the effect of aging on reproductive health. He was conducting experiments that required him to mate female and male worms.

"I saw a dramatic reduction in the size of the females," said Shi, "so I started taking additional images and measuring the effect." Shi began exploring how the sperm or its surrounding seminal fluid could cause the shrinkage and death.

He discovered that seminal fluid acts on a biological process that helps the worms conserve energy during times of stress. The seminal fluid acts on a transcription factor, or protein, called DAF-16 in the nucleus of cells that turns on the genes necessary to respond to stresses such as heat or low nutrients. In mated females, the factor is somehow driven out of the nucleus so it cannot activate the stress response system, causing fat loss and lifespan decrease.

Sperm acts via another mechanism to shorten longevity, Shi found. The sperm causes the shut-off of a factor called DAF-9 that activates a separate nuclear hormone stress response pathway involving another molecule called DAF-12, leading to water loss, shrinking and shortened lifespan.

The researchers found that the lethal effect occurred not only in the elegans species but also in other types of worms from the Caenorhabditis genus that are not hermaphroditic. "The fact that it is conserved in true male-female species, not just hermaphrodites, suggests that it is an important, conserved biological mechanism," Murphy said. Although it is not yet known whether sperm and seminal fluid also kill other animals after mating, the longevity pathways involved are conserved in other organisms.

"Our results indicate that there are factors in seminal fluid and sperm that shut off these two stress-response mechanisms," Murphy said. "It is a one-two punch, with two independent pathways that males use to kill the females."



INFORMATION:

The research was supported by a National Institutes of Health New Innovator award.

The paper, "Mating Induces Shrinking and Death in C. elegans Mothers," appears in the Dec. 19 issue of Science.



ELSE PRESS RELEASES FROM THIS DATE:

Landscape architecture study places value on Klyde Warren Park, other urban spaces

2013-12-20
Landscape architecture study places value on Klyde Warren Park, other urban spaces New research area tells entities what public projects are worth A UT Arlington landscape architect and his graduate students have published three case studies for the 2013 Case ...

Telecoupling science shows China's forest sustainability packs global impact

2013-12-20
Telecoupling science shows China's forest sustainability packs global impact As China increases its forests, a Michigan State University (MSU) sustainability scholar proposes a new way to answer the question: if a tree doesn't fall in China, can you hear it elsewhere ...

New ways to promote fitness for urban girls proposed by Rutgers-Camden nursing professor

2013-12-20
New ways to promote fitness for urban girls proposed by Rutgers-Camden nursing professor Most people know that one of the keys to reducing or preventing health problems is to get more exercise, but determining how to best integrate physical activity into their ...

Disabled shoppers confront holiday shopping barriers

2013-12-20
Disabled shoppers confront holiday shopping barriers Before chestnuts roast on the fire and sugarplums dance in the dreams of youngsters, the holiday season elicits visions of crowded parking lots and malls overrun by shoppers while retailers try to keep up with ...

Bullying in academia more prevalent than thought, says Rutgers-Camden scholar

2013-12-20
Bullying in academia more prevalent than thought, says Rutgers-Camden scholar CAMDEN — Bullying isn't only a problem that occurs in schools or online among young people. It can happen anywhere to anyone, and a Rutgers–Camden nursing scholar is shedding some ...

CCNY chemists use sugar-based gelators to solidify vegetable oils

2013-12-20
CCNY chemists use sugar-based gelators to solidify vegetable oils Mannitol and sorbitol dioctanoates could provide alternatives to trans fats linked to obesity, coronary artery disease and diabetes Researchers at The City College of New York have reported the ...

Oh, the places you'll go -- if you're an Atlantic slipper shell

2013-12-20
Oh, the places you'll go -- if you're an Atlantic slipper shell New research reveals the biomechanics of how marine snails swim Walk the beach or peer into a tidepool anywhere along the northeastern U.S. coast, and you'll find shells stacked on top of one another. ...

Saving fertility not priority at most cancer centers

2013-12-20
Saving fertility not priority at most cancer centers Lack of policies to protect cancer patients' fertility at top cancer centers CHICAGO --- Infertility is consistently listed as one of the most distressing long-term side effects of cancer treatment for adolescents ...

Ancient cranial surgery

2013-12-20
Ancient cranial surgery UCSB bioarchaeologist studies trepanation -- a practice of drilling holes in the cranium that dates back thousands of years Cranial surgery is tricky business, even under 21st-century conditions (think aseptic environment, ...

Dual catalysts help synthesize alpha-olefins into new organic compounds

2013-12-20
Dual catalysts help synthesize alpha-olefins into new organic compounds Boston College researchers combine two catalytic reactions to produce highly reactive compounds CHESTNUT HILL, MA (Dec. 19, 2013) – Boston College chemists have developed a new chemical synthesis methodology ...

LAST 30 PRESS RELEASES:

Drug-delivering aptamers target leukemia stem cells for one-two knockout punch

New study finds that over 95% of sponsored influencer posts on Twitter were not disclosed

New sea grant report helps great lakes fish farmers navigate aquaculture regulations

Strain “trick” improves perovskite solar cells’ efficiency

How GPS helps older drivers stay on the roads

Estrogen and progesterone stimulate the body to make opioids

Dancing with the cells – how acoustically levitating a diamond led to a breakthrough in biotech automation

Machine learning helps construct an evolutionary timeline of bacteria

Cellular regulator of mRNA vaccine revealed... offering new therapeutic options

Animal behavioral diversity at risk in the face of declining biodiversity

Finding their way: GPS ignites independence in older adult drivers

Antibiotic resistance among key bacterial species plateaus over time

‘Some insects are declining but what’s happening to the other 99%?’

Powerful new software platform could reshape biomedical research by making data analysis more accessible

Revealing capillaries and cells in living organs with ultrasound

American College of Physicians awards $260,000 in grants to address equity challenges in obesity care

Researchers from MARE ULisboa discover that the European catfish, an invasive species in Portugal, has a prolonged breeding season, enhancing its invasive potential

Rakesh K. Jain, PhD, FAACR, honored with the 2025 AACR Award for Lifetime Achievement in Cancer Research

Solar cells made of moon dust could power future space exploration

Deporting immigrants may further shrink the health care workforce

Border region emergency medical services in migrant emergency care

Resident physician intentions regarding unionization

Healthy nutrition and physical lifestyle choices lower cancer mortality risk for survivors, new ACS study finds

Mass General Brigham researchers reveal 17 modifiable risk factors shared by stroke, dementia, and late-life depression

Promising drug discovery research gets funding boost from Ontario Institute for Cancer Research

Carbon capture could become practical with scalable, affordable materials

USC Norris Comprehensive Cancer Center opens state-of-the-art Newport Beach Radiation Oncology and Imaging Center

Chan Zuckerberg Biohub New York announces new investigators for immune system research to improve human health

New research suggests White Americans in areas with higher Black poverty are more likely to blame racial inequality on lack of effort

Solar wave squeezed Jupiter’s magnetic shield to unleash heat

[Press-News.org] Mating is the kiss of death for certain female worms