purcc 2012 - University of the Pacific

Poster Session Abstracts
Pyriform Spidroin 2 (PySp2) is a component
found in the pyriform gland of orb-weaving
spiders such as Nephila clavipes, and is essential
to the formation of attachment disks. These glue
silk fibers have high tensile strength and are nontoxic,
and attach dragline silk to surfaces to
allow for locomotion and web construction. The
toughness of the fiber is attributed to both the
spinning conditions and the overall protein
architecture. The PySp2 protein has a distinct
set of internal block repeats containing segments
of specific repeating amino acids, which
contribute to the overall polarity and the
successful assembly of the proteins into fibers.
We plan to test the significance of each block
repeat and the resulting relationship to the
mechanical properties of the attachment disk
fibers. cDNA constructs containing each internal
repeat have been inserted and expressed in the
pBAD-Thio-TOPO expression vector. Our long
term goal is to purify the recombinant fusion
protein and spin these proteins into synthetic
fibers. Mechanical properties of the fibers will
then be tested and compared to those of naturally
spun fibers of orb-weaver attachment discs.
ZipK Influence on Apoptosis and Cell
Migration
Christine Hsu
Faculty Mentor: Doug Weiser
Apoptosis, programmed cell death, is important
for numerous physiological functions and in
preventing tumor formation. ZipK is a member
of the DAPk family of serine/threonine kinases
that regulates apoptosis. ZipK is also implicated
in the regulation of cell migration. Two of its
main substrates are myosin light chain and
mypt1. Mypt1 has a role in cell movement
during gastrulation, a stage of early vertebrate
development. Studies have shown that cell
movement during gastrulation is similar to cell
movement in cancer. Thus, these experiments
will give insights into how ZipK regulates
processes associated with cancer. In order to
study the effects of ZipK and its substrates on
apoptosis and cell migration, the Weiser lab
sought to purify zebrafish ZipK protein
expressed in E. coli cells. Although ZipK is
found in vertebrates, zebrafish was chosen as the
genetic model as rodents show significant
divergence in their gene sequence for ZipK.
Some of the methods used include Polymerase
Chain Reaction (PCR), Gel Electrophoresis,
Silica Gel Isolation, and Restriction Digests.
Attempts to express full-length ZipK showed
poor expression. It was hypothesized that the
GST construct of the E. coli expression vector
was too large to be expressed efficiently.
Recently, we have generated a truncated GST
segment and will attempt to express this
construct in E. coli.
Isolation and Characterization of Cyanin
Chloride from Strawberries
Gurbir Gudial
Faculty Mentor: Andreas Franz,
Ilona Serebnitskaya (graduate student)
Strawberries are convenient sources of
polyphenolic compounds that have documented
ability to act as radical scavengers and hence
might be of general benefit to human health. We
have reproduced a published method for the
isolation of one specific poylphenolic compound,
cyanin chloride; a red-colored pigment.
Strawberries were homogenized and were
subjected to Soxhlet extraction (methanol). The
evaporated extract was redissolved in water and
was partitioned between several organic
solvents. The fractions were analyzed by Thin
Layer Chromatography and Matrix-Assisted
Laser Desorption/Ionization Time-Of-Flight
Mass Spectrometry (MALDI-TOF-MS). A
commercially available cyanin chloride standard
was used for reference, and its structure was
confirmed by extensive NMR spectroscopy. The
identity of the commercial standard and the
extracted cyanin chloride was confirmed.
Molecular Modeling to Determine Acidity
and Basicity of Organic Compounds
Bhupinder Padda
Faculty Mentor: Jianhua Ren
Acidity is associated with losing protons while
basicity is associated with gaining protons. In
both instances, molecules can go from a neutral
state to an ionic state. This can greatly affect the
structure of a molecule and may also change its
function. My research is focused on looking at
the acidity and basicity for a series of common
organic compounds. The ability of an organic
compound to form ions depends largely on its
strength as an acid or a base. This information
can be used alongside mass spectrometry data to
better understand ionization efficiency.
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