Mangrove killifish are small fish—only about an inch or two long—that live in temporary pools in the coastal mangrove forests of Central and South America and Florida. During dry seasons when their pools disappear, the fish hole up in leaf litter or hollow logs.
As long as they stay moist, they can survive for extended periods out of water by breathing air through their skin. But oxygen isn't the only thing a fish out of water needs to worry about, according to Professor Patricia Wright, a biologist from the University of Guelph, Ontario, who has studied these fish for years.
"All cells in the body need the right combination of ions and water for an animal to stay alive," Wright explains. "Normally, the gills are responsible for these processes in fish. We knew that in mangrove killifish the gills are likely useless on land, so how these fish maintain ion balance out of water was a mystery."
Wright's latest research, published in the November/December 2010 issue of the journal Physiological and Biochemical Zoology, shows that the skin of the mangrove killifish picks up the slack for the gills.
Through a series of laboratory experiments, Wright and her team found special cells called ionocytes clustered on the skin of the fish. Ionocytes, normally found on the gills of other fish, are the cells responsible for maintaining the right balance of water and salt in a fish's cells.
"We found the mangrove killifish have roughly as many ionocytes on their skin as on their gills," Wright said. Other fish species have skin ionocytes in larval stages of development, but usually these cells disappear in the skin as the fish develops.
To show that these skin ionocytes were doing the job, the researchers took some mangrove killifish out of water for a period of 9 days. During that time, the fish were left on a surface moist with water containing a radioactive isotope. The researchers found that the isotope eventually turned up in the fish's body.
"It's very clear they're exchanging ions through the skin," Wright said.
The skin of the mangrove killifish is also equipped to help the fish deal with varying salinity, the research found. When out-of-water fish were placed on a surface moist with salt water, the skin ionocytes got bigger, indicating that they're working overtime to keep the right salt balance. When those fish were placed back in water, the skin ionocytes returned to normal size.
It's adaptations like this, Wright says, that make this fish special—even among amphibious fish. Lungfish, for example, need to alter their physiological state to live out of water. But with its special skin, mangrove killifish can maintain all of their normal physiological processes at nearly the same level as being in water—and they can do it for over 60 days.
"They really are very interesting little animals," Wright said.
Danielle M. LeBlanc, Chris M. Wood, Douglas S. Fudge, and Patricia A. Wright, "A Fish Out of Water: Gill and Skin Remodeling Promotes Osmo- and Ionoregulation in the Mangrove Killifish Kryptolebias marmoratus." Physiological and Biochemical Zoology 83:6. An abstract is available here: http://www.journals.uchicago.edu/doi/abs/10.1086/656307.
Physiological and Biochemical Zoology has presented current research in environmental, adaptational, and comparative physiology and biochemistry since 1928. The journal publishes the results of original investigations in animal physiology and biochemistry at all levels of organization, from the molecular to the organismic, focusing on adaptations to the environment. Physiological and Biochemical Zoology is coedited by Drs. Kathleen M. Gilmour and Patricia M. Schulte.
Kevin Stacey | EurekAlert!
Rutgers-led innovation could spur faster, cheaper, nano-based manufacturing
14.02.2018 | Rutgers University
New study from the University of Halle: How climate change alters plant growth
12.01.2018 | Martin-Luther-Universität Halle-Wittenberg
A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.
In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...
A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.
By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...
Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
23.02.2018 | Physics and Astronomy
23.02.2018 | Health and Medicine
23.02.2018 | Physics and Astronomy