Page 5 - R&KT Flipping Book - Issue 5, Dec 2016

highlights
A Major Breakthrough in Environmental Issue FIve

Science: Low Oxygen Causes Transgenerational

Reproductive Impairments in Fish

“Hypoxia is a pressing problem worldwide, and is particularly
A research team led by Professor Rudolf Wu imminent in Hong Kong and China. Large amount of nutrient-rich
Shiu-sun, Research Chair Professor of Biological wastewater being disposed of in the ocean has caused excessive
Sciences of the Education University of Hong phytoplankton growth, which has led to hypoxia,” said Professor
Kong (EdUHK), has discovered, for the first time Wu. Given that hypoxia can cause transgenerational reproductive
in science, that low oxygen (hypoxia) can cause impairments in fish, it will have a long-lasting impact on our
transgenerational reproductive impairments in fishery resources and marine ecosystems, he added.
fish – a major breakthrough in environmental
science and management. This study also has significant biomedical implications. “Since the
epigenetics and sex hormones regulation mechanisms are highly
conserved in both fish and humans, hypoxia caused by apnea
The four-year research project was conducted jointly by EdUHK, (disturbance of breathing during sleep) or high altitude disease in
City University of Hong Kong, Hong Kong Baptist University, the human patients may also lead to reproductive impairment in their
Chinese University of Hong Kong and the University of Hong children and grand children,” he said.
Kong. The researchers continually tracked and compared the
“If timely measures are not taken, the subsequent damage
reproductive ability of adult fish and their offspring for three
to humans and marine organisms may be long lasting and
generations grown under hypoxia and normal oxygen. They also
irreversible in many subsequent generations.” Professor Wu
monitored fish kept for one generation in hypoxia but returned to
concluded.
normal oxygen for another two generations.
The team discovered that the two subsequent generations
produced by parents who had lived under hypoxia had a lower
level of male hormones, poorer sperm quality and lower sperm
motility and fertilisation success, despite having never been
exposed to hypoxia throughout their life. This exciting discovery
was published in the authoritative scientific journal Nature
Communications.

Researchers continually tracked and compared the reproductive ability of adult marine From the left:
medaka and their offspring for three generations grown under hypoxia and normal Dr Richard Kong, Associate Professor of the Department of Biology and Chemistry,
oxygen. The City University of Hong Kong;
Dr Zhang Jiangwen, Associate Professor of the School of Biological Sciences,
The University of Hong Kong;
Professor Rudolf Wu, Research Chair Professor of Biological Sciences at
The Education University of Hong Kong;
Professor Alice Wong, Professor of the School of Biological Sciences,
The University of Hong Kong; and
Dr Jill Chiu, Assistant Professor of the Department of Biology,
The Hong Kong Baptist University

R & KT News 5