A few years ago, scientists at the University of Idaho discovered birth control pills not only control the human population, but also can devastate rainbow trout populations. Now they may know why.
James Nagler, professor of biological sciences, recently discovered that 17á-ethynylestradiol – an active chemical in birth control pills – causes cells in rainbow trout to have an abnormal number of chromosomes. This condition, known as aneuploidy, is often found in cancer cells, causes Down’s syndrome in humans, and may be why many embryos fathered by exposed specimens die within three weeks.
The results, coauthored with Kim Brown and Joe Cloud from the University of Idaho, and Irvin Schultz of Battelle Pacific Northwest National Laboratory – Marine Science Laboratory were published in this week’s edition of the Proceedings of the National Academy of Sciences.
“The bottom line is that aneuploidy is abnormal and highly undesirable,” said Nagler. “I believe this compound is causing elevated levels of sperm aneuploidy, which in turn is greatly reducing the embryonic survival rate in the fish it affects.”
Nagler exposed male rainbow trout to the chemical and tested their sperm for abnormal chromosome levels. He then fertilized eggs from unexposed females with the affected semen and compared the resulting offspring’s survival rate with a control group that was not exposed to the synthetic estrogen.
The results showed that while offspring sired by healthy male and female fish enjoyed a three-week survival rate of more than 95 percent, only 40 to 60 percent of the young trout from the affected semen survived. Additionally, the abnormal chromosomal levels were passed on to some of the offspring.
The chemical 17á-ethynylestradiol is a synthetic estrogen commonly used in human birth control pills and is released into the environment through urination. The compound is difficult to remove in waste treatment plants, and very few plants are capable of removing the chemical before releasing the water back into the environment.
“The concentrations we tested are not found everywhere,” said Nagler. “But there are definitely many places in the world containing levels close to – if not exceeding – the concentration that we tested.”
There are other synthetic estrogens released into the environment every day besides 17á-ethynylestradiol. Similar chemicals are found everywhere from detergents to pesticides and cause many more problems than chromosome abnormalities. For example, the pesticide DDT – a weak estrogen – caused the egg shells of bald eagles to be thin and weak, contributing to their declining numbers during the mid-1900s.
Nagler’s research results raise many questions on the levels of synthetic estrogens in surface water across the country and how they might be affecting all animals using the water, including humans.
“Nobody can say that these compounds are the main cause of salmon decline because it’s a very complex issue and there are many, many factors involved,” said Nagler. “But it can’t help.”
Image is available at www.today.uidaho.edu/PhotoList.aspx
Ken Kingery | Newswise Science News
How does the loss of species alter ecosystems?
18.05.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig
Excess diesel emissions bring global health & environmental impacts
16.05.2017 | International Institute for Applied Systems Analysis (IIASA)
The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde.
The researchers demonstrated the feasibility of using plasma to amplify short laser pulses of picojoule-level energy up to 100 millijoules, which is a 'gain'...
Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.
Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
29.05.2017 | Earth Sciences
29.05.2017 | Life Sciences
29.05.2017 | Physics and Astronomy