Navigation Links
Ready for mating at the right time
Date:8/29/2014

This news release is available in German.

The exchange of chemical signals between organisms is considered the oldest form of communication. Acting as messenger molecules, pheromones regulate social interactions between conspecifics, for example, the sexual attraction between males and females. Fish rely on pheromones to trigger social responses and to coordinate reproductive behavior in males and females. Scientists at the Marine Science Center at the University of the Algarve in Faro, Portugal, and at the Max Planck Institute for Chemical Ecology in Jena, Germany, have now identified such a signal molecule in the urine of male Mozambique tilapia (Oreochromis mossambicus): this pheromone boosts hormone production and accelerates oocyte maturation in reproductive females. Hence, the Mozambique tilapia is one of the first fish species in which the chemical structure of a pheromone has been identified and the biological basis of its activity elucidated. (Current Biology, August 21, 2014, doi: 10.1016/j.cub.2014. 07.049)

The social behavior of Mozambique tilapias (Oreochromis mossambicus) native to southern Africa is very complex. The strict hierarchic ranking among males is fought out in so-called courtship arenas. With their mouths, male tilapias make excavations in the sand in the middle of an arena with the aim of attracting females to spawn in these nests. At the same time, they act aggressively to keep other males away. Dominant males have been observed to urinate more often and squirt larger quantities of urine in the water during fights compared to their subordinate rivals. The urine contains pheromones that reduce aggressive behavior in other males. The compounds also lure females to the nest and modify their hormonal status by accelerating oocyte maturation. Thus the pheromones help to synchronize female spawning and external fertilization by the males and so to increase the odds of reproductive success.

Tilapias also show this behavior in captivity, which makes them an ideal model system for reproducible biological assays. Tina Keller-Costa and her colleagues at the Marine Science Center at the University of the Algarve in Faro, Portugal, as well as the Biosynthesis/NMR Research Group at the Max Planck Institute for Chemical Ecology in Jena, Germany, have now identified the chemical structure of the signaling molecules in tilapia males and studied their function. She collected urine samples from dominant males and purified the samples in several steps, testing them for biological activity as pheromones after each step.

Two steroids as main components in the urine

This procedure resulted in two pure substances whose chemical structures were elucidated using nuclear magnetic resonance spectroscopy (NMR). Their identity was confirmed by chemical synthesis: "The two structures are stereoisomers or mirror images of a pregnane-type steroid linked to glucuronic acid," Bernd Schneider, the head of the NMR lab in Jena, said, summarizing the results of the analysis.

Both males and females showed highly sensitive responses to the odor of these two steroids. Although the two pheromone components stimulate the hormonal system of the females and trigger spawning, they are not by themselves capable of reducing aggressive behavior in rival males. The researchers thus assume that the urine of dominant males must contain additional yet-to-be identified substances that contribute to this effect in a complex mixture.

Until now only very few fish pheromones have been chemically identified. "Our discovery will allow for further investigations, for example, of the mechanisms of perception and processing of these chemical signals by the brain in order to originate a response, in this case oocyte maturation and behavioral changes," says Tina Keller-Costa, who conducted the experiments for her PhD thesis.

Ways to control invasive fish species and benefits for the aquaculture of food fish

Apart from the carp family, tilapias belong to the most important edible fish raised commercially. However, their aquaculture in many tropical and subtropical waters has led to an uncontrolled population growth and spread of the species. The use of pheromones could help optimize the aquaculture of tilapia species by increasing female fertility and reducing aggression between competing males. Pheromones could also help to control the invasive behavior of these fish, which threatens the ecological balance of many ecosystems. [AO/BS]


'/>"/>

Contact: Dr. Bernd Schneider
schneider@ice.mpg.de
49-364-157-1600
Max Planck Institute for Chemical Ecology
Source:Eurekalert  

Related biology news :

1. Single-cell parasites co-opt ready-made genes from host: UBC research
2. RedBrick Health Launches Open Integration and Partner Certification Program, Selects Fitbit, RunKeeper Among First to be "RedBrick Ready"
3. HALO: One-of-a-kind research aircraft ready for takeoff
4. Humans were already recycling 13,000 years ago
5. NYSCF scientists develop new protocol to ready induced pluripotent stem cell clinical application
6. Wistar receives $1.5 million Department of Defense grant to ready prostate drug for clinical use
7. Pizza perfect! A nutritional overhaul of junk food and ready-meals is possible
8. Children are significantly more likely to develop PTSD if the mother is already afflicted
9. Feeding by tourists compromises health of already-endangered iguanas, study finds
10. Museum bird DNA ready for use in Naturalis Biodiversity Center
11. Are we ready for contact with extraterrestrial intelligence?
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Ready for mating at the right time
(Date:6/2/2016)... 2, 2016   The Weather Company , an IBM ... an industry-first capability in which consumers will be able to ... ask questions via voice or text and receive relevant information ... Marketers have long sought an advertising solution that ... be personal, relevant and valuable; and can scale across millions ...
(Date:5/16/2016)... --  EyeLock LLC , a market leader of iris-based ... IoT Center of Excellence in Austin, Texas ... embedded iris biometric applications. EyeLock,s iris authentication ... with unmatched biometric accuracy, making it the most proven ... platform uses video technology to deliver a fast and ...
(Date:4/28/2016)... , April 28, 2016 First quarter 2016: ... up 966% compared with the first quarter of 2015 ... SEK 589.1 M (loss: 18.8) and the operating margin was 40% ... 0.32) Cash flow from operations was SEK 249.9 M ... revenue guidance is unchanged, SEK 7,000-8,500 M. The operating ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... Md. , June 23, 2016 A person ... from the crime scene to track the criminal down. ... the U.S. Food and Drug Administration (FDA) uses DNA evidence ... Sound far-fetched? It,s not. The FDA ... sequencing to support investigations of foodborne illnesses. Put as simply ...
(Date:6/23/2016)... 23, 2016   EpiBiome , a precision microbiome ... in debt financing from Silicon Valley Bank (SVB). The ... to advance its drug development efforts, as well as ... "SVB has been an incredible strategic partner to ... traditional bank would provide," said Dr. Aeron Tynes ...
(Date:6/23/2016)... BEACH, Calif. , June 23, 2016  Blueprint ... new biological discoveries to the medical community, has closed ... co-founder Matthew Nunez . "We have ... us with the capital we need to meet our ... will essentially provide us the runway to complete validation ...
(Date:6/23/2016)... ... 2016 , ... Velocity Products, a division of Morris Group, ... exclusively for Okuma CNC machining centers at The International Manufacturing Technology Show, IMTS, ... companies with expertise in toolholding, cutting tools, machining dynamics and distribution, Velocity SMART ...
Breaking Biology Technology: