| UC
Riverside researchers from the Departments of Chemical
and Environmental Engineering, Mechanical Engineering
and Botany and Plant Sciences have worked together to
discover a way to utilize Quantum Dot bio-conjugates
to uncover new knowledge about the binding of a protein
at the growing pollen tube tip. This protein plays a
critical role along with another protein (chemocyanin)
in guiding sperm-laden pollen tubes to the eggs found
in ovules. Applying nanoparticles for imaging the protein
localization revealed information that could not be
observed previously by conventional imaging techniques.
This study provides a new tool to botanical scientists
by merging areas of materials science, chemistry and
plant biology.
The findings are the result
of an interdisciplinary research team including Sathyajith
Ravindran of the Chemical and Environmental Engineering
Department; Sunran Kim, Rebecca Martin and Elizabeth
M. Lord of the Botany and Plant Sciences Department;
and Cengiz S. Ozkan of the Mechanical Engineering
Department at UC-Riverside.
The results of their collaborative
research appeared in an article titled “Quantum Dots
as Bio-labels for the Localization of a Small Plant
Adhesion Protein” and published in the January 2005
issue of Nanotechnology, and is a featured article
at http://nanotechweb.org. Journal Nanotechnology
has an international readership among academic, government
and corporate sectors, and is dedicated to coverage
of all aspects of nanoscale science and technology
from a multidisciplinary perspective.
Ozkan and his colleagues utilized
cadmium selenide (CdSe) quantum dots coated with zinc
sulphide as fluorescent probes. The particles had
a diameter of 6.3 nm. The team terminated the quantum
dots with carboxylic groups by reacting them with
mercaptoacetic acid. Then they conjugated the quantum
dots with the amine groups of stigma/stylar cysteine-rich
adhesin (SCA) - a plant pollen tube adhesion protein.
This labeled the protein molecules with fluorescent
tags.
Quantum dots are much more
resistant to photobleaching than conventional fluorescent
markers and their small size make them ideal for biological
imaging. The researchers then added the molecules
to germinated lily pollen grains and examined them
under a confocal microscope.
This is the very first time
that Quantum Dots have been utilized for live imaging
in plant systems. The study opens the door for the
potential use of Quantum Dots in live imaging of plant
cells and provides valuable understanding of the mechanism
of interaction between the pollen tube and female
tissue during reproduction.
“Integrating materials science,
chemistry and plant biology to understand how and
where specific proteins act on a pollen tube is one
more step towards a better understanding of the fundamental
processes involved, namely the network of the signaling
process in plant reproduction,” said Ozkan. "A
better understanding of the interaction of SCA with
pollen tubes could help with successful plant breeding”.
Related Links:
Nanotechnology journal
Additional Contacts:
Cengiz S. Ozkan
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