A team led by Patrick Martin of the National Oceanography Centre has shown that a species of planktonic marine alga can rapidly change the chemical composition of its cell membranes in response to changes in nutrient supply. The findings indicate that the process may be important for nutrient cycling and the population dynamics of phytoplankton in the open ocean.
Tiny free-floating algae called phytoplankton exist in vast numbers in the upper ocean. Through the process of photosynthesis, they use the energy of sunlight to produce organic compounds required for growth, which draws large amounts of carbon dioxide down from the atmosphere. However, they also need other nutrients such as phosphorus, which is chronically scarce in many oceanic regions.
"We are interested in the adaptations of phytoplankton living in regions where nutrients are in short supply," explained Patrick Martin.
Under normal growth conditions, the cell membranes of phytoplankton contain phosphorus-based lipids called phospholipids. However, it has been appreciated for some time that phytoplankton can exchange their membrane phospholipids with non-phosphorus lipids when phosphorus is in short supply. This substitution saves the cells some phosphorus, which can then be used for other important growth processes such as making new DNA.
"Until now, it has been unclear how rapidly phytoplankton cells are able to change the phosphorus composition of their membranes, and hence whether this process is important over the life-time of individual cells" said Patrick Martin.
To address the issue, he and his collaborators from Woods Hole Oceanographic Institution (WHOI) in the United States performed growth experiments with a species called Thalassiosira pseudonana, which biologists use as a model species representative of a very important group of phytoplankton called diatoms.
They found that when the diatoms were starved of phosphorus their membrane phospholipids were replaced with lipids lacking phosphorus over a couple of days. Moreover, when the diatoms were re-supplied with phosphorus, they rapidly renewed the phospholipid content of their cell membranes, removing the lipids lacking phosphorus.
"Our research now shows that this substitution, at least in the alga we studied, can take place within 24 hours, and is clearly a physiological response by individual cells to the phosphorus concentration in their environment – as opposed to a longer-term adjustment over successive generations," said Patrick Martin.
The researchers also show that when cells have ample phosphorus, their phospholipids contain a surprisingly large amount of phosphorus. Therefore, if these cells suddenly encounter low phosphorus conditions, they have quite a substantial phosphorus reserve in their lipids, which might be significant for supporting further growth.
"Phosphorus concentrations in the ocean can be locally enhanced by physical features such as eddies in the water, and rapid remodelling of lipid membranes might allow phytoplankton to exploit such conditions," said Patrick Martin.
The researchers are Patrick Martin (NOC), and Benjamin Van Mooy, Abigail Heithoff and Sonya Dyhrman (WHOI). The work was conducted while Patrick Martin visited Woods Hole on an exchange programme last autumn.
This research was funded by the United States' National Science Foundation and by the Graduate School of the NOC in Southampton.
Publication: Martin, P., Van Mooy, B. A. S., Heithoff, A. & Dyhrman, S. T. Phosphorus supply drives rapid turnover of membrane phospholipids in the diatom Thalassiosira pseudonana. ISME J. (published online, 16 December 2010).
Dr Rory Howlett | EurekAlert!
Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel
Removing fossil fuel subsidies will not reduce CO2 emissions as much as hoped
08.02.2018 | International Institute for Applied Systems Analysis (IIASA)
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.
The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...
Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.
Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...
A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.
Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
18.05.2018 | Power and Electrical Engineering
18.05.2018 | Information Technology
18.05.2018 | Information Technology