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Biomedical Sciences Seminar Series

Spring 2009 Poster Presentation
May 15, 2009 at 1 pm
Physical Sciences Lobby

Poster #1- Benjamin Bush

Solving Shirokuro Puzzles with a Backtracking Algorithm
Authors: Benjamin Bush, Dr. Russ Abott

Shirokuro is an obscure Japanese puzzle recently featured in Spirit magazine. The puzzle is played on a grid of N x N cells, each of which may be empty or contain a disk that is either black or white in color. The goal of Shirokuro is to fill in every empty cell with a white or black disk so that the following conditions are satisfied: (1) No two-by-two region of the grid contains four disks of the same color. (2) Every white disk is connected to every other white disk through a chain that connects horizontally or vertically through only white disks. (3) Every black disk is connected to every other black disk through a chain that connects horizontally or vertically through only black disks. A backtracking algorithm is used to solve Shirokuro puzzles by incrementally building candidate solutions and abandoning each partial solution as soon as it has been deemed useless. Similar methods have been used to solve many other types of puzzles, such as the 8 Queens, Shirokuro, and Instant Insanity puzzles.


Poster #2-Michelle Flores

Examining the Effects of Familism and Racial Identity on Latino
College Students' Academic Motivation
Authors: Flores, Michelle & Kohatsu, Eric

Despite their demographic growth, Latinos continue to trail behind other racial groups in education (Torres, 2004). Although research has shown the positive aspects of familial support, studies have also found that excessive family involvement may impair an individual’s academic motivation (Gonzalez & Ortiz, 2000). Literature on Latino academic motivation has largely overlooked racial identity in explaining outcomes in Latino education. The lack of research on this area may contribute to the belief that Latinos’ academic underachievement is largely a result of cultural, rather than racial factors.
It is predicted that individuals operating from the Conformity or Integrative Awareness status will have higher academic motivation than those operating primarily from the Dissonance or Resistance statuses. It is expected that women will score higher on items measuring family connectedness, while men will score higher on items measuring family obligation and perceived support.
A target sample of 150 Latino participants (ages 18-30) is expected.
Counseling and research implications will be discussed.


Poster #3- Anita Mihecoby

Understanding Discrepancies between Asian & Latino College Student Success
Anita Mihecoby, MA psychology

The purpose of this study was to explore differences between 74 AsianAmerican and 108 Latino college students (64% female, 26% male; M= 23 years) in parental support variables (academic encouragement and financial support) and academic variables (GPA and academic engagement behaviors). T-tests showed that Asian Americans were significantly higher on academic variables (GPA and academic engagement) SES, parental educational encouragement, and financial support. Regressions showed that for Asian Americans less parental academic encouragement, less work hours, and more academic engagement predicts higher GPA’s. For Latinos, higher parental occupation and more academic engagement behaviors predicted higher GPA’s. Parents and academic engagement behaviors are important for academic success for both Asian and Latino students


Poster #4-Irving Phillips

Identifying essential genes of Acinetobacter baumannii
using an antisense expression strategy

Authors: Irving J. Phillips, H. H. Xu.

Abstract Background: A. baumannii is a Gram negative, MDR soil bacterium that is responsible for pneumonia, urinary tract infection, endocarditis, surgical-site infection, meningitis, and septicemia. Essential proteins, which are encoded by essential genes, are absolutely required for bacterial growth and survival. Consequently, the products of essential genes identified in pathogenic bacteria can be used as targets for the discovery of novel antibiotics. One important strategy for identifying bacterial essential genes is regulated antisense expression. An antisense expression strategy enables the down-regulation of gene expression at the post-transcriptional level using an inducible promoter and a plasmid vector containing an internal fragment of a gene in the antisense orientation. If the gene is essential, robust synthesis of the antisense RNA will inhibit cell growth thus confirming the essentiality of the gene by binding to the cognate mRNA to render the mRNA nonfunctional largely by increasing its degradation. We hypothesize that the downregulation of A. baumannii’s endogenous genes with an inducible antisense expression vector system can be used to identify genes that are essential to the growth and survival of the organism. This hypothesis will be tested in A. baumannii by constructing a vector that contains an inducible promoter that controls expression of a cloned DNA fragment in the vector. Reporter gene xylE, which encodes catechol 2,3 -dioxygenase, will be used to evaluate the activity and function of an inducible promoter in A. baumannii. Catechol 2,3-deoxygenase catalyzes the conversion of the colorless substrate catechol into hydroxymuconic semialdehyde, which is yellow in color. This compound can be measured spectrophotometrically to provide a measure of gene expression in xylE-containing recombinant cells when catechol is added. This poster will present results of cloning xylE gene into pLEX5BA and the subsequent analysis of promoter activity located on this plasmid.


Poster #5-Omar Moreno

Measurement of the Analyzing Power for the Reactions Here we present the analyzing power measurement for the reactions ~p+(CH2)n ! X and ~p+(CH2)n ! p at a proton momentum of 2.2032 GeV/c.

The azimuthal angular distribution of polarized protons scattered in the (CH2)n analyzer is sensitive to the strength of the spin- orbit coupling or analyzing power of the reaction ~p+(CH2)n ! X. Recoiling protons produced in the ~e + p ! e0 + ~p reaction are polarized. The recoil polarization technique, used to measure the ratio of the electromagnetic form factors Gp E=Gp M of the proton, involves measuring the induced polarization of the proton with the use of the Focal Plane Polarimeter (FPP). The FPP is composed of two blocks of (CH2)n with pairs of drift chambers interleaved. Measurement of the analyzing power to a high degree of accuracy is important since it will signicantly reduce the error in the electromagnetic form factor measurement. Furthermore, knowledge of the analyzing power can be used to optimize the characteristics of the FPP for future experiments. Insight into the electric charge and magnetic dipole moment distributions in the pro- ton can be used to test Quantum Chromodynamics calculations of the proton's quark con- stituents. The Gp E-III experiment at the Thomas Jeerson National Accelerator Facility has made measurements of the ratio of the Sachs form factors, Gp E=Gp M, up to a four momentum transfer of Q2 = 9:00 GeV2 via the recoil polarization technique. The work described in this presentation supports this experimental program for the Q2 = 2:733 GeV2 point.


Poster #6-Dewayne Anderson

Microfluidic Devices to Determine the Efficacy of Using Surface Bound Early Transition Metal Complexes in the Silylcyanation of Aldehydes

DeWayne D. Anderson The testing of catalysts is often carried out at a macroscopic level, where millimole quantities of compounds and catalyst are used to determine the selectivity and activity of a catalyst. More efficient methods to determine these properties maybe available, but have not been proven with Lewis acid catalysts. This project plans to: one, determine if microfluidic devices (MDs) can be used in nano-scale reactions; two, determine the enantioselectivity of different catalysts; and three, find active systems to determine the enantioselectivity of a given reaction. In order to determine if MDs can be used to perform all three tasks, it is important to find the efficacy of a catalyst at a macroscale level, and then determine if the same type of efficacy can be observed in MDs. Thus, four areas must be examined; the efficacy of supported catalysts on a macroscale level; the effect of substrates on catalyst efficiency; the ability of the supported complexes to act as chiral chromatographic media, and; the ability to reuse supported complexes for a catalytic task that a supported complex seems best suited for. In order to determine if MDs in a catalytic generated reaction, it is important to determine the timescale of a reaction and the physical properties of products from Lewis acid catalyzed reactions, with different types of aldehydes using gas chromatography. Gas chromatography with an achiral column will be used to monitor the reaction followed by a chiral column for determination of enantiomeric composition. Afterwards, MDs can be used on a nano-scale level in order to determine if they can be used in lewis acid catalyzed reactions, and their use in identifying different properties of products from aldehyde silylcyanation reactions. Once all of the previous steps mentioned have been completed, we should be able to identify promising separating medias used in MDs, and the ability of the devices to determine the enantioselectivity of a catalyst.  

Poster #7-Danielle Barrios

Human Immunodeficiency Virus type 1 Integrase Inhibition
by Ketoacid-based Compounds

Danielle Barrios and Nouri Neamati, PhD Integration of viral DNA into the host chromosome is an essential component of the HIV replication cycle. This step is mediated by HIV integrase (IN), a 32 kD enzyme that has no mammalian counterpart, rendering it a particularly attractive target for antiviral drug design. Integrase inhibitors from diverse chemical classes have been identified and, among them, the beta-diketoacid (DKA) class of compounds has shown the most promising results. The discovery of DKAs as potent IN inhibitors was a major advance in validating IN as a viable target for the development of drugs against AIDS. The study details the results of in vitro inhibition assays to identify novel inhibitors from a library of modified ketoacid compounds. The major goal of the study is to extend the work on ketoacid-based compounds by characterizing the relationship of the functional group modifications to the activity of the ketoacid as an IN inhibitor.  


Poster #8- Isba Silva


Over the past 20 years we have found a dramatic increase in multi drug resistant pathogenic strains. These pathogens present a serious threat to the public health, highlighting an urgent need for novel antibiotics. In the past 20 years, about 50% of successful compounds in clinical trials have been derived from natural origin. Regrettably, in the pharmaceutical industry the interest in Natural Products (NPs) is reduced and the focus has been placed on combinatorial chemistry. However, interest in NPs is reemerging recently. In this study, we focus on the identification of antibacterial inhibitors from NPs, by high throughput screening (HTS) and via an array of Escherichia coli clones each over-expressing one essential protein for target identification. Recently, we have conducted cell-based HTS for inhibitors against Escherichia coli ATCC#25922 and Staphylococcus aureus ATCC#29213 using two NP libraries (1120 NPs). Four compounds have been found to inhibit growth by more than 80% in both E. coli and S. aurous. Additionally, 8 hits were found to inhibit E. coli growth alone while 26 hits were found to inhibit S. aureus growth only. Future studies include determination of potency of the discovered compounds and identification of the target essential proteins.  

Poster #9- Adrian Esqueda

The discovery of novel inhibitory compounds against human apurinic endonuclease 1 (APE1) in vitro.

Abstract: Human apurinic endonuclease 1 (APE1) belongs to endonuclease family involved in the base excision pathway. APE1 is an enzyme that repairs damaged or mismatched bases in DNA by removing the base, leaving a sugar phosphate residue. APE-1 has been shown to be overexpressed in specific cancers including colon making it an ideal target for the development of new anti-cancer drugs. In combination with alkylating and oxidizing agents, it has been shown that inhibition of APE1 in cancer cells leads to a high degree of DNA damage eventually leading to apoptosis. Using an enzymatic assay and gel electrophoresis, training sets of compounds designed with an abasic DNA fragment as the template are tested for inhibition of APE1 activity.


Poster #10-Xiomara Madero

Isolation of luciferase protein from bioluminescent secretions of
Vargula tsujii ostracodes
Xiomara Madero

Abstract: Bioluminescence occurs due to the interaction of a luciferase enzyme with a luciferin substrate. Vargula tsujii is a bioluminescent ostracode crustacean that is found off the coast of California and Baja California. It secretes luciferin and luciferase into the seawater, producing a bright luminous cloud of blue light emitted at 465 nm. The Vargula luciferase gene has been characterized from two species of Japanese ostracodes, and is not homologous to other known luciferases. It is found only in ostracodes and some fish species. Attempts to isolate Vargula tsujii luciferase cDNA with probes and primers based on Japanese cDNA sequences has proved unsuccessful. The goal of this project is to isolate V. tsujii luciferase protein from bioluminescent secretions produced by ostracodes. Protein from secretions in seawater are quantified, concentrated, and analyzed by SDS-PAGE. The goal is to isolate luciferase protein in order to design species-specific probes and primers for isolation of V. tsujii luciferase gene sequences. Comparison of V. tsujii luciferase with the published Vargula luciferases will give possible insight into the evolution of bioluminescence in ostracodes.  


Poster #11- Rebecca Borja

Construction of +HIS +ARG double knock out in replacement of the diploid fungi Candida Albicans gene YCK2 using PCR knock out approach

Abstract: The overall objective of this experiment is to construct a double knockout of the diploid fungi Candida Albicans strain BWP17 by replacing its YCK2 gene with +HIS and +ARG consecutively. The methodology applied was to PCR-amplify the HIS plasmid and insert in BWP17 genome through transformation. Gel electrophoresis results show that HIS transformation was successful for colony sets #4, 11, and 14 around 1.5kb while using a 1kb ladder. Future project entails ARG transformation to obtain a successful double knockout. This would serve as an aid to insert a constructed YCK2 complement strain into the double knockout BWP17 genome.  


Poster #12- Celeste Mendoza

Perceived Acculturation Conflicts in Latino Families

Mendoza, C. M, & Dennis, J. M

In immigrant families, a gap often exists between the cultural values and expectations of young people and their parents. This can lead to intergenerational conflict, family stress, and poorer psychological well-being and adjustment among family members. The purpose of this study is to examine the acculturation gap between Latino parents and their children and to examine how this gap relates to intergenerational conflicts in expectations regarding appearance, autonomy, and dating relationships. Participants include Latino college students between the ages of 18 and 24 years. It is predicted that conflicts with parents will be associated with higher levels of depression, lower self-esteem, and higher acculturative stress. Results will explore the psychological well-being of Latino college students and the types of family conflicts that are experienced as a result of an acculturation gap.  


Poster #13- Victor Cazares

Orbitofrontal cortex lesions impair responses to cue predicting
shifts in work to reward in rats.

Victor A. Cazares MA Psychology
Faculty Mentor: Alicia Izquierdo

The orbitofrontal cortex (OFC) is a neural mediator of adaptive decision making. Specifically, the OFC is recruited in situations involving change: changes in the value of a goal and in expected outcomes. Reports in rodents suggest that the OFC does not mediate all choices involving changes in reward value, namely, that it is uninvolved in situations where the reward value is depreciated by increasing the amount of work to obtain it. To address this issue, the current study assessed rats’ performance on a modified version of an effort-based t-maze task in which they were required to scale barriers of different heights to obtain a large food reward. In a novel, critical test phase, rats were required to learn and respond to a visual cue predicting changes in the work to reward. Rats with OFC lesions were unable to use a visual cue to guide their choices between a high reward versus a low reward, but instead unselectively became work-intolerant. This is the first evidence that the OFC is involved in the ability to use a cue to guide behavior when that cue predicts a change in the effort to obtain the reward. Supported by the NIH MBRS-RISE Program at CSULA.  


Poster #14-Bernardo Ferreiro

Improvement of Calcium Binding to a Reversible Calcium
Cage via the Chelate Effect

Abstract: Calcium is an important second messenger in several biological processes, but its concentration oscillations are not well understood. A photochromic compound that can effectively mimic these oscillations would aid our understanding of these important biological mechanisms. A previously synthesized photochrome has been found to bind and release calcium upon irradiation with light, but for it to function effectively in biological systems its binding affinity to calcium needs to be increased 1000-fold. One approach to increasing the binding affinity is to increase the number of chelating groups at the binding site. A mimic of the new photochrome is being synthesized in order to determine the impact that additional chelating groups will have on the compound’s binding affinity to calcium. A necessary step in the multi-step synthesis of both the open and closed forms of the mimic is the synthesis of N-benzyl-N,N’,N’-tris(tert-butyloxycarbonylmethyl)ethylenediamine, which has been performed several times, first using Dry Flash Column Chromatography then alternately using Flash Column Chromatography to purify the products. To date, purification attempts have not yielded satisfactory results.  


Poster #15-Sieara Claytor

Genetic variation in translocated fox squirrels (Sciurus niger) in California Authors: Sieara Claytor, Dr. Muchlinski, Dr. Torres

Abstract: The fox squirrel (Sciurus niger) is native to the central and eastern United States and the southern prairie provinces of Canada. It was introduced into many cities within California in the late 1800s and early 1900s. It is possible that the animals for each of the introductions came from a different region within the natural geographic range of the species and therefore they could have represented different subspecies. It is also very possible that each of the introductions was composed of a small number of fox squirrels. After this introduction, further differentiation could have occurred. Therefore, the combination of a Founder Effect and genetic drift may be evident in the current genetic structure of the isolated populations of fox squirrels within California. Information about the evolutionary relationships is calculated via sequence divergence of the d-loop region of the mitochondrial DNA.  


Poster #16-Rose Bustos

Measuring the Reduction Potential of Superoxide Dismutase Copper-zinc superoxide dismutase (SOD1) is a protein rich in copper and zinc that is found in various areas of the human cell, including the cytosol, nucleus, peroxisomes and mitochondrial intermembrane space. SOD1 is an antioxidant enzyme that lowers the steady state concentration of superoxide . A diverse group of over 100 different mutations have been associated with the same disease, amyotrophic lateral sclerosis (ALS), commonly known as Lou Gehrig's disease. The wide variety of mutations, ranging from slight variations to dramatic deviations from wild type, all cause this same disease, making it difficult to hypothesize about the exact cause of ALS. Discovering the reduction potential of the mutant protein would result in a more complete understanding of the enzyme’s mechanisms including the tendency for this enzyme to participate in oxidation and reduction reactions. There were two distinct methods projected to measure the reduction potential for SOD mutants: molecular wire synthesis and spectroelectrochemistry. The molecular wire consisted of a head group, an intermediate linker group and a gold electrode. This synthetic method has proven to be more precise than alternative methods used in measuring reduction potentials but required building new wire system that was unprecedented in previous biochemical studies of SOD1. Preliminary results show successful synthesis of the molecular wire and further research will reveal whether the molecular wire can successfully measure the reduction potential of SOD-1 at the enzyme’s active site. The second method chosen to measure reduction potential was spectroelectrochemisty. This practice had been more thoroughly studies in previous literature to measure enzymatic activity and was selected because of its proven success in measuring the reduction potential of wild type SOD1. Refining of the electrochemical cell will be the focus of future work to assure the most effective dimensions are attained before a reduction potential can be accurately deduced for the superoxide mutants.  


Poster #17-Wayne Warner

In silico screening and in vitro analysis of safe drugs that can
inhibit MDM2 binding to p53.

Wayne A. Warner and Jamil Momand Ph.D.

Cellular stresses can negatively impact genomic integrity and induce changes that culminate in tumorigenises. The tumor suppressor p53 is activated in response to these stresses and can transactivate other genes that are involved in cell cycle control, senescence, apoptosis and DNA repair. Activation of p53 has been linked to the suppression of tumor formation. MDM2 binds to p53, effectively stimulating p53 degradation. In many types of cancers, MDM2 is over expressed and the functional concentration of p53 is compromised. The p53/MDM2-binding interface is between the N terminus of the p53 a-helix and a hydrophobic cleft on the N terminus of MDM2. Van der Waals interactions between Leu-26, Phe-19 and Tyr-23 of p53 and Leu-54, Met-62, Tyr-67, Val-93 of MDM2 anchor this protein-protein interaction. Inhibition of MDM2 will lead to p53 stabilization with increased transcription of p53 target genes and decreased proliferation of tumor cells expressing wild type p53. We have analyzed MDM2 small molecule inhibitors to discern the common structures necessary for inhibition and a theoretical consensus skeletal inhibitor was developed. This skeletal inhibitor will be screened against a structure database of FDA-approved drugs in silico to discover potential lead compounds that may be MDM2 inhibitors. The optimal lead compounds will then be experimentally screened for inhibition of MDM2 activity in vitro and restoration of p53 fidelity.


Poster #18-James O'Hearn

Endorsement of PeptideMass and PeptideCutter Proteomics Software Tools

Jim O’Hearn Dr. Momand’s Laboratory BIOMED PREP

Phosphoenolpyruvate carboxylase (PepC) and bovine serum albumin (BSA) were alkylated and trypsinized. Iodoacetamide (IAM) was used to alkylate cysteine residues and trypsin was used to cleave the proteins at the carboxyl terminus of arginine and lysine residues except those followed by proline residues. Fragments were analyzed by Matrix Assisted Laser Desorption/Ionization – Time of Flight Mass Spectrometry (MALDI-TOF MS) and Liquid Chromatography/Mass Spectrometry (LC/MS). Two proteomics tools, PeptideMass and PeptideCutter, were used for reactivity predictions. PeptideMass calculates masses of peptides and their post-translational modifications and PeptideCutter predicts potential protease and cleavage sites and sites cleaved by chemicals in a given protein sequence. Results have yielded accurate masses of predicted alkylated cysteines for PepC and BSA.  


Poster #19-Amy Shimamoto

Colorblindness as Predictors of anti-Asian Prejudice among Latinos Racism, along with negative racial attitudes and prejudice, continues to be the most difficult, sensitive, and persistent social problems in the U.S. (Peterson, 2007). Much attention has focused on interpersonal racism between Blacks and Whites, yet little empirical research has examined racism between Latinos and Asians (Mio, 2004). This gap in knowledge proves surprising given that Latinos and Asians are emerging racial minority groups in the U.S. (Moradi & Risco). Studies have shown that interracial contact between Asians and Latinos has been contentious of the Model Minority Myth (Kohatsu, 2007). For some Latinos, the competition for resources can generate harmful psychological effects and increase prejudicial attitudes towards Asians. Asian Americans are stereotyped both in positive (seemingly) and negative ways. The positive stereotyping of Asian Americans such as being successful, intelligent, erroneously perpetuate the idea that Asians have overcome all hardships in America and serve as the basis of the Model Minority Myth. The negative stereotypes of Asians as unsociable, nerdy, and humorless may also produce negative attitudes towards Asians (Ho & Jackson, 2001). Ho & Jacksons’ Attitudes Towards Asians Scale was used in order to measure the level in which the participants adhered to these stereotypes. Researchers can deepen the understanding of anti-Asian prejudice using a color-blindness framework. The current study utilized Neville’s Colorblindness Scale in order to examine the extant to which the participants believed that racism is no longer a relevant, important issue affecting the social and economic climate. Past studies have shown that individuals who adhere to color-blind racial attitudes express higher levels of racism towards other racial groups (Gushue, 2004). Kohatsu et al. (2007) found that both racial identity and colorblind frameworks were robust predictors of anti-Asian prejudice among People of Color. Racial Identity examines the process by which People of Color overcome negative self and own group perceptions to develop an integrated identity based on a realistic understanding of the sociopolitical history of their group (Helms, 1995). For the purposes of this study the People of Color Racial Identity Scale, developed by Helms, was used. Racial identity, as measured empirically, can be expressed in four statuses: Conformity (e.g., adherence to the White dominant culture), Dissonance (e.g., ambivalence and confusion of one’s own socioracial group commitment), Resistance (e.g., idealization of one’s socioracial group and denigration of other groups), and Integrative Awareness (e.g., capacity to value one’s own identities and empathize with members of other people of color). However, few studies have been done on how these two variables can predict anti-Asian prejudice among Latinos. Therefore, the purposes of this study were to examine 1) the extant to which racial identity can predict anti-Asian prejudice and Color-Blindness among Latinos; and b) extent to which racial identity can predict the reported levels of negative personal experiences with Asians. Participants were solicited from social science classes using a standardized protocol. The overall return response rate was 95%. An anonymous questionnaire was administered and included the Attitudes Toward Asian Scale, Color-Blind Racial Attitudes Scale, People of Color Racial Identity Attitudes Scale, and a demographic data sheet. Hierarchical regression analyses were conducted to examine the extent to which racial identity can predict anti-Asian prejudice and color-blind racial attitudes among Latinos. All six models were significant and, due to space constraints, only two models will be presented. Racial identity attitudes were significant predictors of overall negative attitudes (R2 = 19%) and the beta weights indicated that the more one subscribed to Resistance status attitudes, the lower the levels of colorblindness. You need to pick an example that is more representative of the study – select one that predicts anti-Asian prejudice and NOT color-blindness!. Clearly, racial identity predicted anti-Asian prejudice and color-blind racial attitudes in theoretically consistent ways and is therefore an important variable to include when investigating racism-related issues among Latinos. Implications for cross-cultural counseling will be discussed.  


Caridad Wilson
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