"Normal sperm cells contain an arc-like structure called the acrosome that is critical in fertilization because it houses, organizes, and concentrates a variety of enzymes that sperm use to penetrate an egg," said Manabu Nakamura, a U of I associate professor of biochemical and molecular nutrition.
The study shows for the first time that docosahexaenoic acid (DHA) is essential in fusing the building blocks of the acrosome together. "Without DHA, this vital structure doesn't form and sperm cells don't work," said Timothy Abbott, a doctoral student who co-authored the study.
Men concerned about their fertility may wonder what foods contain DHA. Marine fish, such as salmon or tuna, are excellent sources of this omega-3 fatty acid.
The scientists became intrigued with DHA's role in creating healthy sperm when they experimented with "knockout" mice that lack a gene essential to its synthesis. "We looked at sperm count, shape, and motility, and tested the breeding success rate. The male mice that lacked DHA were basically infertile," Nakamura said.
But when DHA was introduced into the mice's diet, fertility was completely restored. "It was very striking. When we fed the mice DHA, all these abnormalities were prevented," he said.
The scientists then used confocal laser scanning (3D) microscopy to look at thin slices of tissue in progressive stages of a sperm cell's development. By labeling enzymes with fluorescence, they could track their location in a cell.
"We could see that the acrosome is constructed when small vesicles containing enzymes fuse together in an arc. But that fusion doesn't happen without DHA," he said.
In the absence of DHA, the vesicles are formed but they don't come together to make the arch that is so important in sperm cell structure, he noted.
Nakamura finds the role this omega-3 fatty acid plays in membrane fusion particularly exciting. Because DHA is abundant in specific tissues, including the brain and the retina as well as the testes, the scientists believe their research findings could also impact research relating to brain function and vision.
"It's logical to hypothesize that DHA is involved in vesicle fusion elsewhere in the body, and because the brain contains so much of it, we wonder if deficiencies could play a role, for example, in the development of dementia. Any communication between neurons in the brain involves vesicle fusion," he noted.
The Illinois scientists will continue to study sperm; meanwhile, Nakamura has sent some of his DHA-deficient knockout mice to other laboratories where scientists are studying DHA function in the brain and the retina.
The study was published in a recent issue of Biology of Reproduction. Co-authors are Manuel Roqueta-Rivera, Timothy L. Abbott, Mayandi Sivaguru, and Rex A. Hess, all of the U of I. The work was supported in part by a CONACyT Mexico fellowship award.
Phyllis Picklesimer | EurekAlert!
A new 'cool' blue
17.01.2020 | American Chemical Society
Neuromuscular organoid: It’s contracting!
17.01.2020 | Max-Delbrück-Centrum für Molekulare Medizin in der Helmholtz-Gemeinschaft
Styrofoam or copper - both materials have very different properties with regard to their ability to conduct heat. Scientists at the Max Planck Institute for Polymer Research (MPI-P) in Mainz and the University of Bayreuth have now jointly developed and characterized a novel, extremely thin and transparent material that has different thermal conduction properties depending on the direction. While it can conduct heat extremely well in one direction, it shows good thermal insulation in the other direction.
Thermal insulation and thermal conduction play a crucial role in our everyday lives - from computer processors, where it is important to dissipate heat as...
In order to advance the transfer of research developments from the field of quantum sensor technology into industrial applications, an application laboratory is being established at Fraunhofer IAF. This will enable interested companies and especially regional SMEs and start-ups to evaluate the innovation potential of quantum sensors for their specific requirements. Both the state of Baden-Württemberg and the Fraunhofer-Gesellschaft are supporting the four-year project with one million euros each.
The application laboratory is being set up as part of the Fraunhofer lighthouse project »QMag«, short for quantum magnetometry. In this project, researchers...
Microtubules, filamentous structures within the cell, are required for many important processes, including cell division and intracellular transport. A...
Researchers from the University Hospital Zurich, ETH Zurich, Wyss Zurich and the University of Zurich have developed a machine that repairs injured human livers and keep them alive outside the body for one week. This breakthrough may increase the number of available organs for transplantation saving many lives of patients with severe liver diseases or cancer.
Until now, livers could be stored safely outside the body for only a few hours. With the novel perfusion technology, livers - and even injured livers - can now...
A balloon-borne scientific instrument designed to study the origin of cosmic rays is taking its second turn high above the continent of Antarctica three and a half weeks after its launch.
SuperTIGER (Super Trans-Iron Galactic Element Recorder) is designed to measure the rare, heavy elements in cosmic rays that hold clues about their origins...
16.01.2020 | Event News
15.01.2020 | Event News
07.01.2020 | Event News
17.01.2020 | Life Sciences
17.01.2020 | Power and Electrical Engineering
17.01.2020 | Life Sciences