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Light microscopy facility opens

Light Microscopy shared resource

Through the looking glass, St. Jude researchers peer into a tiny world of proteins, cells and organisms inside the new Cell and Tissue Imaging Center’s Light Microscopy Division.

Passing by the new 1,500-square-foot space, St. Jude staff and visitors can gaze through ceiling-high windows at these colorful worlds brought to life on flat-screen computer monitors.

The Light Microscopy Division has recently moved into the new space, which now houses all the light microscopy needs of researchers in one area. From an image of a simple histology stained sample to a complex study of molecular interactions, the Cell and Tissue Imaging Center staff can accommodate a diverse range of scientific inquiry.

The facility was created on the recommendation of a task force that was formed by St. Jude Scientific Director James Downing, MD. The task force was assembled to determine what kind of facilities investigators needed to enhance their research capabilities. From the task force’s plan, the Cell and Tissue Imaging shared resource encompasses two areas under separate supervision – light microscopy and electron microscopy. The electron microscopy facility opened earlier this year on the plaza level of the Danny Thomas Research Center.

“What sets this shared resource apart from other microscopy core facilities is the collaborative nature of the interactions between the investigators and the staff of the light microscopy area of the Cell and Tissue Imaging shared resource,” said Michael Dyer, PhD, Developmental Neurobiology, who headed the task force. “Light Microscopy director Samuel Connell and his team will work with investigators to help them find solutions to their imaging challenges and move their research forward as quickly and efficiently as possible.”

Light microscopy includes confocal laser scanning microscopy, multiphoton microscopy, and live cell imaging and microinjection. Confocal microscopy is an essential light microscopy technique that obtains optical sections through a fluorescently tagged specimen. Multiphoton microscopy uses pulses of long-wavelength light to analyze thick samples. Cell microinjection allows the introduction of precise amounts of foreign material into specific regions of living cells. The biological effects of this injection are then monitored by either light or fluorescence microscopy in real time.

“This is a place for discovery as well as for documentation,” Connell said about the new facility. “We are trying to develop techniques that are on the frontier of live and fixed cell imaging, and bring them directly to St. Jude researchers, shortening the timeline for the development of new projects within the laboratories.”

The Light Microscopy staff includes Connell; Linqing Zhang, PhD; Simon Moshiach, PhD; and Jennifer Peters, PhD. Some high-end techniques employed by light microscopy include Fluorescent Recovery After Photobleaching (FRAP), which measures the dynamics of protein movement within a cell; Fluorescent Lifetime Imaging Microscopy (FLIM), which directly examines protein complexes and molecular interactions; and Total Internal Reflection Fluorescence (TIRF), the highest-resolution technique available in light microscopy that queries at or near the membrane of living cells.

One of the facility’s newest instruments, a Marianas from Intelligent Imaging Innovations, is a six-laser spinning disc confocal microscope ideally suited for short and long-term imaging of living specimens. The Marianas is also used for FLIM and TIRF applications. Six different microscopes—each one geared toward a different niche of discovery—are housed in the area. Other techniques and instruments include spectral unmixing and widefield monochrome and color cameras.

As a National Cancer Institute Comprehensive Cancer Center shared resource, the facility can be used by scientists from across the institution, creating an environment where investigators can communicate with light microscopy staff members in the planning and execution of projects to glean data that can be used for presentation or publication in high-impact journals. Key-card access for trained users allows the facility to be available after hours on nights and weekends.

“The images are full of data; they are not just pictures,” Connell said. “Each one of the pixels of an image has numbers in it, and our job is to pull out those important numbers that actually tell a quantitative story about the science done at St. Jude.”

Specimens routinely examined in the Cell and Tissue Imaging Center include fixed cells and tissues as well as living cells and tissues. The optical slice technologies and software in the center enable researchers to perform accurate 3-D reconstructions of their specimens.

September 2008

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