A few years ago, manufacturers of water bottles, food containers, and baby products had a big problem. A key ingredient of the plastics they used to make their merchandise, an organic compound called bisphenol A, had been linked by scientists to diabetes, asthma and cancer and altered prostate and neurological development. The FDA and state legislatures were considering action to restrict BPA's use, and the public was pressuring retailers to remove BPA-containing items from their shelves.
The industry responded by creating "BPA-free" products, which were made from plastic containing a compound called bisphenol S. In addition to having similar names, BPA and BPS share a similar structure and versatility: BPS is now known to be used in everything from currency to thermal receipt paper, and widespread human exposure to BPS was confirmed in a 2012 analysis of urine samples taken in the U.S., Japan, China and five other Asian countries.
According to a study by University of Texas Medical Branch at Galveston researchers, though, BPS also resembles BPA in a more problematic way. Like BPA, the study found, BPS disrupts cellular responses to the hormone estrogen, changing patterns of cell growth and death and hormone release. Also like BPA, it does so at extremely low levels of exposure.
"Our studies show that BPS is active at femtomolar to picomolar concentrations just like endogenous hormones —that's in the range of parts per trillion to quadrillion," said UTMB professor Cheryl Watson, senior author of a paper on the study now online in the advance publications section of Environmental Health Perspectives. "Those are levels likely to be produced by BPS leaching from containers into their contents."
Watson and graduate student René Viñas conducted cell-culture experiments to examine the effects of BPS on a form of signaling that involves estrogen receptors — the "receivers" of a biochemical message — acting in the cell's outer membrane instead of the cell nucleus. Where nuclear signaling involves interaction with DNA to produce proteins and requires hours to days, membrane signaling (also called "non-genomic" signaling) acts through much quicker mechanisms, generating a response in seconds or minutes.
Watson and Viñas focused on key biochemical pathways that are normally stimulated when estrogen activates membrane receptors. One, involving a protein known as ERK, is linked to cell growth; another, labeled JNK, is tied to cell death. In addition, they examined the ability of BPS to activate proteins called caspases (also linked to cell death) and promote the release of prolactin, a hormone that stimulates lactation and influences many other functions.
"These pathways form a complicated web of signals, and we're going to need to study them more closely to fully understand how they work," Watson said. "On its own, though, this study shows us that very low levels of BPS can disrupt natural estrogen hormone actions in ways similar to what we see with BPA. That's a real cause for concern."
This research was supported by the Passport Foundation and the National Institutes of Health.
Jim Kelly | EurekAlert!
Laser activated gold pyramids could deliver drugs, DNA into cells without harm
24.03.2017 | Harvard John A. Paulson School of Engineering and Applied Sciences
What does congenital Zika syndrome look like?
24.03.2017 | University of California - San Diego
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy