May 2, 2012
Study Shows Transgenerational Effect Of Antibiotics
Antibiotic commonly used in animal production passes from father to son in pseudoscorpions
In a paper published in Nature's open access journal Scientific Reports, researchers at the University of Nevada, Reno, report that male pseudoscorpions treated with the antibiotic tetracycline suffer significantly reduced sperm viability and pass this toxic effect on to their untreated sons. They suggest a similar effect could occur in humans and other species.A pseudoscorpion, whose scientific name is Cordylochernes scorpioides, is a tiny eight-legged arachnid that has the false appearance of a scorpion. Its sperm packets are transferred externally, making it possible for investigators to simply collect them and assess the quality and quantity of sperm.
"This is the first research to show a transgenerational effect of antibiotics," said David Zeh, lead author and chair of UNR's department of biology in the College of Science. "Tetracycline has a significant detrimental effect on male reproductive function and sperm viability of pseudoscorpions--reducing viability by up to 25 percent--and now we know that effect is passed on to the next generation. We didn't see the effect in subsequent generations."
The research involved a three-generation study of the pseudoscorpion. To control for genetic influences, in the first generation, brothers and sisters from each of 21 broods were treated with weekly doses of tetracycline, an antibiotic commonly used in animal production and generally used for treatment of infections in humans. The broods were treated from birth to adulthood or were reared as untreated controls. Subsequent generations were not treated with tetracycline. The antibiotic had no effect on male or female body size, sperm number or female reproduction, they found.
"Tetracycline, one of the most widely used antibiotics, has previously been shown to have negative effects on male reproduction in vertebrates, including humans," said George Gilchrist, program director in the Division of Environmental Biology at the National Science Foundation, which funded the study.
"This study confirms that effect in these unusual invertebrates, but also demonstrates a toxic effect across generations. It is of broad importance because of the potential for cross-generational effects on the fertility of food animals and humans, which has never before been examined."
Image Caption: In an article published in Nature's open access journal Scientific Reports, lead author and assistant biology professor Jeanne Zeh surmises that tetracycline may induce epigenetic changes in male reproductive tissues that may be passed to sons--changes that do not alter the sequence of DNA but rather alter the way genes are expressed. Here, a Cordylochernes scorpioides births nymphs, the males of which may be negatively affected by tetracycline. Credit: Nick Romanenko
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