The lipid A in plant cells is evidently not toxic. The human intestine contains billions of Gram-negative bacteria, but lipid A does not become a problem unless bacteria invade the bloodstream.
"We've no idea what it's doing, but it must be something important because it's been retained for a billion years of evolution of plant chloroplasts," said Peter Armstrong, professor of molecular and cellular biology at UC Davis and senior author on the paper.
Endotoxin is better known to bacteriologists and physicians as part of the outer coat of Gram-negative bacteria such as E. coli. The lipid A core of bacterial endotoxin activates the immune system and can cause septic shock, a major cause of death from infection. It is distinct from the toxin found in E. coli strain 0157, responsible for the recent outbreak of food poisoning tied to spinach.
Bacteria were thought to be the only source of lipid A. However, R.L. Pardy, professor at the University of Nebraska-Lincoln, recently found a similar molecule in Chlorella, a single-celled relative of more advanced plants. Armstrong's lab at UC Davis developed methods to visualize lipid A in cells, using a protein from the immune system of the horseshoe crab, and the researchers began collaborating.
"It was one of those celebratory moments, when I looked in the microscope and saw these gloriously stained algal cells," Armstrong said, describing their first experiment. The group has now found lipid A in chloroplasts of garden pea plants as well as green algae, and Armstrong suspects that it is present in all higher plants with chloroplasts.
That idea is supported by genetics. Sequencing of the Arabidopsis genome -- the first higher plant to have its entire DNA sequence read -- revealed that the common lab plant has all the biochemical machinery to make lipid A, an observation that had gone largely unnoticed until now. Chloroplasts themselves are thought to have evolved from cyanobacteria, independent photosynthetic bacteria that took up residence in ancestral plant cells.
Other authors on the paper, in addition to Armstrong and Pardy, are postgraduate researcher Margaret Armstrong; Steven Theg, professor of plant biology, and graduate student Nikolai Braun at UC Davis; and Norman Wainwright at the Woods Hole Marine Biology Laboratory. The work was funded by the National Science Foundation and is published in the October 2006 issue of the FASEB Journal.
Andy Fell | EurekAlert!
First time-lapse footage of cell activity during limb regeneration
25.10.2016 | eLife
Phenotype at the push of a button
25.10.2016 | Institut für Pflanzenbiochemie
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
25.10.2016 | Earth Sciences
25.10.2016 | Power and Electrical Engineering
25.10.2016 | Process Engineering