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Researchers Study Acoustic Communication In Deep-Sea Fish
Richmond, VA (SPX) Sep 30, 2008 An international research team studying sound production in deep-sea fishes has found that cusk-eels use several sets of muscles to produce sound that plays a prominent role in male mating calls. These findings, published online in the Royal Society journal, Biology Letters, may help researchers gain further insight into acoustic communication in the deep sea and the role of sound in fish behavior. Virginia Commonwealth University Life Sciences biologists Michael L. Fine, Ph.D., Kim Nguyen and Hsung Lin, both graduate students at VCU, together with Eric Parmentier at the Universite de Liege in Belgium, examined the sonic muscles of the fawn cusk-eel, Lepophidium profundorum, a species found in the Atlantic Ocean. "Little is known about acoustic communication in the deep sea because of the difficulties of observing fish in this habitat. Based on anatomy, ophidiid fishes, or cusk-eels, are likely one of the chief sound producers. They have unusual sonic muscles that occur in antagonistic pairs and are typically larger in males," said Fine, a professor in the VCU Department of Biology. Many fish use an organ known as a swim bladder to produce sound. According to Fine, the fawn cusk-eel uses two muscle pairs to pivot a modified rib, 'the wing-like process,' forward. This action stretches the swim bladder. An antagonistic muscle pair then restores the swim bladder to its original position. In previous work outside of the mating season, they found that the tiny intermediate muscle of the fawn cusk-eel was larger in females, which was quite surprising since male fish are usually more vocal than females, said Fine. The research team obtained the fish during the summer mating season and found that intermediate muscle weight increased four fold and had become heavier in males than in females. "Our findings suggest that the intermediate muscle likely assumes a prominent role in sound production of male mating calls and suggest that male sex hormones cause the muscle to grow," he said. According to Fine, fishes make sounds for different reasons, but the two most common types of sounds are made for courtship and agonistic behaviors. Related Links Virginia Commonwealth University Darwin Today At TerraDaily.com
Formula Discovered For Longer Plant Life
Munich, Germany (SPX) Sep 25, 2008Plants that grow more slowly stay fresh longer. In their study now published in PLoS Biology, scientists at the Max Planck Institute for Developmental Biology in Tubingen have shown that certain small sections of genes, so-called microRNAs, coordinate growth and aging processes in plants. These microRNAs inhibit certain regulators, known as TCP transcription factors. These transcription factors in turn influence the production of jasmonic acid, a plant hormone. The higher the number of microRNAs present, the lower the number of transcription factors that are active, and the smaller the amount of jasmonic acid, which is produced by the plant. The plant therefore ages more slowly, as this hormone is important for the plant's aging processes. The researchers have succeeded for the first time in describing the antagonistic regulation of growth and aging in plants. Since the quantity of microRNAs in the plants can be controlled by genetic methods, it may be possible in future to cultivate plants that live longer and grow faster. (PLoS Biology, September 23, 2008) |
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