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Summer 2012 Research Projects

 

  • Iovine | Berger
  • Jellison | Pazzaglia
  • Liu | Lowe-Krentz
  • Jedlicka | Swann
  • Tatic-Lucic | Perry

Defining the mechanism of
PlexinA3 activation by Sema3d

 

Iovine Berger Team 2012
sitting: (l-r) Rachael Barton, Bryan Berger, Ph.D., M. Kathryn Iovine, Ph.D., Joyita Bhadra
standing: (l-r) Alyssa Driscoll, Danica Palocio, Kyaw Min Tun, Kelvin Sanchez, Matt Wolfers

Team Leaders:

M. Kathryn Iovione, Ph.D. (Biological Sciences)
Bryan Berger, Ph.D. (Chemical Engineering)

Graduate Students:

Rachael Barton
Joyita Bhadra

Undergraduate Students:

Alyssa Driscoll
Kyaw Min Tun
Danica Palocio
Kelvin Sanchez
Matt Wolfers

Description of Project:

Signaling pathways are critical for communication between cells during the growth and development of multicellular organisms. For example, signaling through the secreted semaphorin signaling molecules has been shown to mediate diverse cellular functions, including cell adhesion, cell migration, tissue patterning, cell proliferation, viability, and changes in the cytoskeleton. Semaphorins utilize different types of membrane receptors, including the Plexins (Plxns) and the Neuropilins (Nrps). However, it remains unclear how Sema signaling influences its receptors to affect downstream cellular outcomes.  Signaling via Sema3d was found to influence both cell division and joint formation during regeneration of the zebrafish fin skeleton. Recent findings suggest that Sema3d-Nrp2a signaling influences cell division and that Sema3d-PlxnA3 signaling influences joint formation.

The goals of this proposal are to utilize purified Sema3d in functional assays both in vivo and in vitro, and to utilize purified domains of PlxnA3 to define the requirements for receptor activation. Completion of these Aims will provide novel insights into the mechanisms underlying the activities of the Sema3d-PlxnA3 signaling system.

Characterization of E. coli contamination
in the Little Lehigh Creek

 

Team Leaders:

Kristen Jellison, Ph.D. (Civil & Environmental Eng)
Frank Pazzaglia, Ph.D. (Earth & Environmental Sciences)

Pazzaglia Jellison Team 2012
sitting: Frank Pazzaglia, Ph.D., Kristen Jellison, Ph.D.
standing: (l-r) Julie Napotnik, Melissa Plooster, Christal Schwenk, Yanela Cruz, Chris Dempsey

Graduate Students:

Chris Dempsey
Julie Napotnik

Undergraduate Students:

Yanela Cruz
Melissa Plooster
Christal Schwenk

Description of Project:

Elevated E. coli concentrations in the Little Lehigh Creek have recently received a lot of public attention due to the fact that the Little Lehigh is (i) a major source of drinking water in Allentown and surrounding municipalities and (ii) a treasured recreational resource surrounded by one of the most expansive park systems in the state.  We will investigate (i) how E. coli contamination in the Little Lehigh compares to other nearby recreational water supplies, (ii) sources of E. coli in the Little Lehigh, and (iii) the impact of storm events on E. coli contamination and, subsequently, the health and safety of recreational creek users. 

Data generated from this research project will inform policy decisions regarding appropriate land use practices in the watershed and when it is safe to allow recreational activities in the Little Lehigh Creek in the context of prevailing weather conditions.  Furthermore, project results will contribute to the development of remediation strategies to restore water quality throughout the watershed, protect the health of those who come in contact with the creek, and preserve the recreational use of this natural resource. 

Interaction of endothelial cells
with fluid flow in a biomimetic environment

Team Leaders:

Yaling Liu, Ph.D. (Mechanical Engineering & Mechanics)
Linda Lowe-Krentz, Ph.D. (Biological Sciences)

Lowe-Krentz Liu Team 2012
sitting: (l-r) Sara Lynn Farwell, Linda Lowe-Krentz, Ph.D., Yaling Liu, Ph.D., Antony Thomas
standing: (l-r) Cheryn Amo-Adjei, James Bowen, Tina Penksa, Alexander Brown, Aislinn Rowan

Graduate Students:

Sara Lynn Farwell
Antony Thomas

Undergraduate Students:

Cheryn Amo-Adjei
James Bowen
Alexander Brown
Tina Penksa
Aislinn Rowan

Description of Project:

At the interfaces between the blood and tissues are blood vessels with their endothelial cell layers containing the cells that directly interact with the blood.  Everything from lipid transport, to the blood brain barrier, to movement of oxygen into and out of the blood stream, to damage that leads to vascular diseases such as atherosclerosis, to vascular complications of diabetes, to movement of drugs transported in the blood into tissues, starts with critical functions of the endothelial cells and/or their damage in disease development.   Despite these important functions of the endothelium, studying endothelial function is difficult, and model systems rarely mimic the natural blood vessels. 

We will begin the development of endothelial layers in mimetic vascular network models that will allow us to further pursue questions of localized drug delivery, vascular graft responses, and endothelial signal transduction in response to altered flow.   We will first optimize endothelial cell growth on PDMS surfaces modified with various adhesion substrate proteins.  PDMS is ideal for micromachining transparent micro-channels and can be easily molded into vascular channels similar to those found in tissues.   In addition, we will develop computational models for flow in the chambers currently used by us for signal transduction and use those models to identify the best configurations to carry out in the next set of experimental studies.  Finally, we will plan and produce relatively simple channel systems so that we can use experimental data we obtain from current simple flow systems to allow production of more complicated models.  

In the future, the interplay between the modeling and experimental data collection will allow us to better understand the mechanical effects of microvasculature flow on endothelial function and on treatments where efficacy depends on localized flow (e.gs. vascular grafts and drug delivery). 

Neuronal Sex Differences:
Development of an interdisciplinary proteomics-based approach

 

Team Leaders:

Sabrina Jedlicka, Ph.D. (Materials Science & Engineering)
Jennifer Swann, Ph.D. (Biological Sciences)

Swann Jedlicka Team 2012
sitting: (l-r) Timothy Garelick, Jennifer Swann, Ph.D., Sabrina Jedlicka, Ph.D., Emily Geishecker
standing (l-r) Paul Oyefesobi, Chelsea Evans, Jeremiah Kurpat, Caroline Rago

Graduate Student:

Timothy Garelick
Emily Geishecker

Undergraduate Students:

Chelsea Evans
Jeremiah Kurpat
Paul Oyefesobi
Caroline Rago

Description of Project:

The membrane is a very important to cells – it protects the cell from the external environment and it allows substances to enter to leave.  Proteins are chemicals that provide for structure and function of cells and many proteins are found in cell membranes.  In neurons membrane proteins are particularly important as they play crucial roles in the ability of neurons to receive and deliver information and change their structure and function during development or in response to environmental changes, learning and memory. Identification of membrane proteins may lead to the development of new drugs that can help war off or cure disease.  

This project will identify those membrane proteins that play a role in the sexual differentiation.  Proteins will be extracted from the preoptic area and compared to identify differences in structure and amount between male and female rodents.  The preoptic area is a region in the brain that is critical for the normal expression of male sexual behavior but plays little role in the expression of female behavior.  Therefore, identifying differences in the protein make up of this region should lead to better understanding of how membrane proteins contribute to the expression of sex specific behaviors.

Investigation of techniques for cell attraction
on electrode sites of multi electrode arrays
using positive dielectrophoresis

 

Team Leaders:

Svetlana Tatic-Lucic, Ph.D. (Electrical & Computer Engineering)
Susan Perry, Ph.D. (Chemical Engineering)

Tatic-Lucic Perry Team 2012
(l-r): Susanne Petryna, Svetlana Tatic-Lucic, Ph.D., Tianyi Zhou, Susan Perry, Ph.D., Vicki Fluck

Graduate Student:

Tianyi Zhou

Undergraduate Students:

Vicki Fluck
Susanne Petryna

Description of Project:

Multi-electrode arrays (MEAs) are used to measure extracellular signals from neurons, as a means of elucidating the mechanisms involved in neuronal communication which are thought to be important in learning and memory.  In a conventional MEA, neurons are randomly positioned with respect to electrodes, a method which is sub-optimal.  One remedy is to precisely position cell bodies on top of electrodes by chemically patterning “cell permissive” areas around the electrodes. However, this method still has limitations. Therefore, our current solution to precise cell patterning is to actively recruit neurons to electrode sites using positive dielectrophoresis (DEP), which utilizes non-uniform electric fields to attract dielectric spheres, such as neurons, to the areas of the maximum electric field strength (ie, in the area of the electrode).

The proposed BDSI project for 2012 includes investigating the behavior of neuronal cells in a variety of solutions and experimental strategies, in an effort to optimize their ability to respond to DEP electric fields and, at the same time to promote cell survival.  In addition, the project will afford students the opportunity to learn state-of-the-art clean room techniques as they design, fabricate, package and test the next generation MEA devices to be used for precise patterning of primary hippocampal neurons.

 

 

 

 
     
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The Biosystems Dynamics Summer Institute is sponsored by a grant from the
Howard Hughes Medical Institute
to Lehigh University

 
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