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Biomedical Sciences Seminar Series

Spring 2006 Poster Presentation

April 28, 2006 at 1 pm

Physical Sciences Lobby

Poster #1-Rudy Victoria

Analyzing Anti-Asian Hate: Understanding Aversive Racism
Using Racial Identity Theory

Authors: Eric L. Kohatsu, Ph.D., Rodolfo Victoria, B.A., Andrew Lau, B.A., Shannen Vong, B.A., Anna Arredondo, B.A., Katia Barquero, B.A., Andrea Salazar, Jason Lessing, M.A.


Abstract:The Model Minority myth stereotype assumes that Asian-Americans are exempt from the perils of racial discrimination.  Consequently, the stereotype creates the perception that Asian-Americans are overly competent but simultaneously creates the perception that Asian Americans lack sociability skills (Lin, Kwan, Cheung, & Fiske, 2005).  Taken together, these characteristics function to legitimize rejection of Asian Americans in the perception that competence was begotten at the expense of sociability. The purposes of this study were to examine the relationship between color-blind and racial identity attitudes and perceptions of Asian Americans as being overly competent yet unsociable as posited by the Model Minority Myth and the Stereotype Content Model.  67 males and 193 females from a culturally diverse west coast university participated in this study (N =200). Results showed that Anti-Asian American prejudice does seem to be related to racial identity attitudes in a theoretically consistent manner.  Racial identity attitudes were also shown to predict color-blindness in a theoretically consistent manner. Implications will be presented 

Poster #2-Marysol Navarro

Study of the essential mutations for Sendai virus variant F1-R’s enhanced virulence

Marysol Navarro, Joseph T. Seto, and Nancy L. McQueen

Abstract: Sendai virus (SeV) is a murine negative-strand RNA virus.  Wild type (wt) virus causes a localized respiratory tract infection in mice.  A variant, F1-R, causes a systemic infection.  We have identified two determinants that correlate with the systemic infection caused by F1-R.  One of these determinants is the enhanced cleavability of the fusion (F) protein of F1-R that we have attributed to two or more of the six mutations in the F gene.  Cleavage is required for virus infectivity.  Wt F is only cleaved by Tryptase Clara, a protease restricted to the lungs, while F1-R F is cleaved by ubiquitous proteases.  Thus, wt Sendai can only undergo multiple rounds of replication in the lungs while F1-R can undergo multiple rounds of replication in many different organs.

The second determinant is the differential budding behavior of F1-R that we have attributed to two mutations in the matrix (M) gene of F1-R.  Wild type SeV buds from the apical domain of epithelial cells into the lumen of the respiratory tract where it subsequently infects new cells in the respiratory tract to cause a localized infection.  F1-R buds from both the apical and basolateral domains, thus releasing virus into the basement membrane through which it can gain quick access to the bloodstream for dissemination.  Based on studies of a revertant of F1-R that has lost its pantropic phenotype, we originally hypothesized that the two mutations in the M gene of F1-R and a mutation in the F gene that results in an amino acid substitution adjacent to the cleavage site of F (F115) were the only mutations needed for F1-R to cause a systemic infection.  To test this hypothesis we used reverse genetics to make Sendai viruses with various combinations of the F1-R F and M gene mutations.  RGV0 contains all six F1-R F and both M mutations, while RGV1 contains only the F1-R F mutation that encodes F115 and RGV7 contains the F1-R F mutation encoding F115 and both M mutations. Much to our surprise only RGV0 had an F protein with enhanced cleavability and only RGV0 caused a systemic infection in mice.  These results mean that in addition to the F1-R F mutation adjacent to the cleavage site of F that had previously been shown to be critical for the systemic infection caused by F1-R, other mutations in F contribute to the enhanced cleavability of F1-R F and the pantropism of F1-R.

Wt F has a glycosylation site at amino acid 104 that is lacking on F1-R F because of an amino acid change at that site. A loss of an oligosaccharide side chain on an influenza virus strain and functional analyses of glycosylation sites on F suggests that fusion activity and cleavability of F is increased when the glycosylation site at F104 is lost. Therefore, my project is to generate a variant SeV, designated RGV18, with the F1-R amino acid changes at F104 and F115, plus both M amino acid changes. The mutant will be studied in both tissue culture and mice to determine its affects both in vitro and in vivo.  As a first step in this process I have amplified pRGV7, a cDNA plasmid of SeV that contains the F1-R F mutation encoding F115 and both M mutations.  Site directed mutagenesis of pRGV7 will be used to introduce a mutation encoding the F1-R amino acid change at F104.  The resulting plasmid, pRGV18, will subsequently be used to generate the virus, RGV18.


Poster #3- Patricia Castillo

Contribution of Lipids to the Antimicrobial Activity of Human Airway Secretions

Patricia Castillo
Faculty Mentor:  Dr. Edith Porter


Background: Innate immunity provides a first line of defense against microbial invasion. Epithelial cells lining our body surfaces are key contributors in part due to their secretions containing antimicrobial peptides, which can be stimulated by pro-inflammatory cytokines like Interleukin 1-beta (IL1b) and microbial cell wall products such as lipopolysaccharide (LPS) and peptidoglycan (PG).  However, lipids including fatty acids, are also present in epithelial secretions as reported for in milk, saliva, and bronchial secretions. Several studies have found an altered lipid composition in body secretions of patients with diseases that are accompanied by chronic infections. In addition, fatty acids and their derivatives have been utilized as antimicrobials in food industry and as detergents. Hypothesis: We therefore hypothesized that lipids play an important role in innate defense as direct antimicrobial effector molecules and proposed to test this hypothesis by two approaches. First, we wanted to show that nasal fluid contains lipids and that these lipids exert antimicrobial activity in vitro either alone or in conjunction with lysozyme. Second, we wanted to establish an airway epithelial cell culture system and test the inherent killing capacity of epithelial cell secretions in the presence or absence of lipids. Methods: Lipids were extracted from normal nasal fluid according to Bligh & Dyer and analyzed by reverse phase HPLC. Native lipid extracts or commercial lipids were incubated with Pseudomonas aeruginosa and bacterial viability was determined by colony forming unit assays.  Human lung epithelial cells were grown in submerged culture to confluence and incubated at varying concentrations  for up to 72 hours with  the proinflammatory cytokines IL1β and interferon g, the microbial cell products LPS and PG, and the selective lipid secretion inhibitor Pluronic L81. Cell viability was assessed with a fluorescence based commercial microplate assay and a safe treatment range was established.  The lipid composition and protein profiles in the epithelial secretions in response to the various treatments were analyzed by reverse phase HPLC and SDS or acid urea polyacrylamide gel electrophoresis, respectively. Results: Our preliminary data suggests that cholesterol and cholesterol esters belong to the major lipid classes in nasal fluid and that they potentiate the antibacterial activity of lysozyme. Lipid secretion of the first investigated human lung epithelial cells line A549 was minimal even when stimulated, in contrast to the abundant presence of lipids in human bronchial epithelial cell secretions. Significance: If lipids are shown to contribute to innate host defense as effector molecules, diseases with chronic infections can be re-investigated, a new class of antimicrobial agents may be developed and new dietary guidelines may be formulated to include antimicrobial lipids. 


Poster #4- Mehnaaz Haniff

Expression of LKB1 in the Rat Ovary

Mehnaaz Haniff, Dr. Philip S. LaPolt

The serine/threonine kinase LKB1 has been implicated in a wide variety of physiological processes, including regulation of cell viability, metabolism, and tumorigenesis.   LKB1 also acts as an upstream kinase for the AMP-activated protein kinase (AMPK), which has recently been implicated as a regulator of ovarian hormone production and oocyte maturation.   However, little information is available regarding the regulated, cell-specific expression of LKB1 in the ovary.   To examine the expression of LKB1 during different phases of ovarian function, follicular development was induced in immature Sprague Dawley rats via administration of equine chorionic gonadotropin (eCG), followed 52 h later by human chorionic gonadotropin (hCG) to induce ovulation and luteinization.   Ovaries and liver (positive control for LKB1 expression) were harvested from rats at different time points, and protein extracts prepared.   Protein was run on SDS-PAGE gels and then electrophoretically transferred to PVDF membranes, which were used in immunoblot analysis using an antibody which detects LKB1 protein levels.  In addition, blots were analyzed using an antibody for glyceraldehyde phosphate dehydrogenase (GAPDH) to determine equal loading of lanes. Immunoblot analysis revealed a predominant immunoreactive signal of about 52 kDa in liver and whole ovarian tissue, corresponding to the expected size of LKB1.  In preliminary studies, LKB1 levels appeared to be lowest in untreated immature ovaries, and increased after administration of eCG and hCG.  These findings confirm the expression of total LKB1 in the rat ovary, and suggest that LKB1 expression is regulated during hormone-induced follicular development, ovulation, and luteinization.


Poster #5-Jerlisa Arizala

Analysis of Adenylyl Cyclase IX Expression in the Rat Ovary

Jerlisa Arizala, Fangxiong Shi, and Philip S. LaPolt

Abstract:The production of estradiol (E2) by the ovary is vital to the development and maintenance of the female reproductive system.  E2 synthesis is increased by follicle-stimulating hormone (FSH), which acts on G protein-coupled receptors in the ovary, increasing activity of a membrane associated enzyme, adenylyl cyclase (AC).  Activated AC converts ATP into cyclic AMP, which then induces expression of enzymes required for E2 synthesis.  There are several isoforms of AC, but there is little information on the AC isoforms expressed in the ovary.  Preliminary analysis of AC isoform mRNA levels in the ovary indicates that ACIX is a predominant AC isoform in the ovary.  Thus, the goal of this project is to examine the cell-specific, regulated expression of ACIX message and protein levels in the ovary and in cultured rat granulosa cells undergoing hormone-induced maturation.   To begin these studies, brain tissue (positive control for ACIX expression) and ovaries were obtained from immature female rats.  Protein homogenates were obtained, and run on SDS-PAGE gels.  Protein was then electrophoretically transferred to PVDF membranes, which were used in immunoblot analysis of ACIX protein levels.  Immunoblot analysis with an ACIX-specific antibody revealed a predominant immunoreactive signal of about 161 kDa in brain tissue, corresponding to the expected size of ACIX, as well as other nonspecific bands.  However, we have not been able to detect ACIX protein by immunoblot analysis in the ovary to date.  While ACIX mRNA levels are readily detected in the ovary, further ongoing studies are required to clarify whether these ACIX transcripts are translated. 



Poster #6-Ricardo Sanchez

Cysteine Oxidation Prediction Program (COPP): An Algorithm that Predicts Oxidation Propensity of Protein Cysteine Thiols 

Ricardo Sanchez1, Jongwook Woo2, Jamil Momand1
1Department of Chemistry and Biochemistry 2
Department of Computer and Information Systems
California State University, Los Angeles


One of the molecular reactions that hydrogen peroxide partakes in is oxidation of protein cysteine residue sulfhydryl groups (also known as thiols). Hydrogen peroxide is capable of oxidizing sulfhydryl groups to sulfenic acid (S-OH), sulfinic acid (SO2H), sulfonic acid (SO3H), and, most commonly, to disulfides (S-S). Hydrogen peroxide appears to be a signaling molecule capable of increasing or decreasing the normal biochemical activity of target proteins.  Our goal is to understand the primary targets of hydrogen peroxide action within the cell; but at the moment, there are no tools that can reasonably predict whether a protein thiol group is susceptible to oxidation. To aid in the research of hydrogen peroxide signaling we have created an algorithm called the Cysteine Oxidation Prediction Program (COPP) which predicts whether a particular protein thiol group is susceptible to oxidation. This prediction is primarily based on: 1) the solvent water accessibility to the thiol on the protein surface, 2) the availability of functional groups that can stabilize the thiolate ion (-CH2-S-) and 3) the angular orientation of the functional groups relative to the sulfur atom. The algorithm uses atom coordinate data from a set of structurally solved proteins in the Protein Data Bank that have been shown, experimentally, to contain oxidized thiol groups. To test COPP’s prediction accuracy, we constructed a dataset containing 27 proteins with 126 oxidation susceptible thiols and 97 reduced thiols. The accuracy of the COPP program using the “leave-one-out” cross validation method was 83.9 percent.


Poster #7-Albert Cervantes

Global Registration from a Video Sequence

Albert. F. Cervantes and Eun-Young Kang, PhD

 Abstract: Many video processing applications such as video surveillance and video compression deal with video sequences captured by moving cameras and perform camera motion estimation in order to stabilize video frames, remove redundancies within a video sequence and/or detect same objects appearing in different video frames. Among many motion estimation methods, the pair-wise motion estimation method, using a 2D parametric model, has been widely used for its simplicity. This approach estimates 6-affine motion parameters (or an 8-parameter homography) for only temporally successive frames and estimates parameters for non-successive frames by concatenating pair-wise motions. This works well for video sequences that exhibit a linear camera motion such as a camera panning in one-direction. However, when a video sequence exhibits non-linear camera motions, the obtained result from pair-wise motion estimation is insufficient to express accurate motions for multi-frames overlapping spatially but not temporally. It is because the concatenation of these pair-wise motion parameters produces a gross error accumulation. The process to find an accurate motion between non-successive frames while reducing the accumulated error is called “global registration” and is essential for many video applications.


In this project, we aim to 1) implement an efficient pair-wise motion estimation method based on feature matching and 2) extend the method to perform global registration using feature tracking. The accuracy of our method is demonstrated by stitching multi-frames in one common coordinate space (mosaic image) and averaging frame pixel values in overlapping areas where blurriness shows if multi-frames are not globally registered.


Poster #8-Jesus Eduardo Gutierrez

The Three Fundamental Traffic Variables: An Introduction to Traffic Flow

Jesus Eduardo Gutierrez,
Mathematics Department, California State University, Los Angeles


The three fundamental traffic variables: velocity, density, and flow are the foundation for research in traffic modeling.  These three fundamental variables are defined as follows: velocity is the rate at which the position changes with respect to time; density is the number of cars per unit of distance; and flow is the number of cars per unit of time.  We assume the existence of a velocity field which assigns a unique velocity u(x,t) to each point in space, x, at each time, t.  The concept of traffic density waves is investigated under the assumption of nearly uniform traffic flow, and the experimental relationship between car velocity and traffic density is given by a nonlinear partial differential equation.  The equation of conservation of cars expresses the relationship between traffic density and traffic flow which is derived by assuming the number of cars is conserved. 


Poster #9-Joseph Herras


Examination of Skogsbergia lerneri (Ostracoda: Myodocopida: Cypridinidae) from Belize: the use of molecular and morphological tools to distinguish cryptic species

Joseph Heras, Dr. Elizabeth Torres

Abstract: This study will determine whether the morphologically defined species Skogsbergia lerneri consists of unrecognized or cryptic species in Belize.  Currently, the only ostracode species of the genus Skogsbergia that is described from the Caribbean is Skogsbergia lerneri. Samples were collected from coral reef and grass habitats from various regions of the Caribbean and mitochondrial DNA (16s rRNA) sequences were used to construct a phylogentic tree for S. lerneri in the Caribbean (Torres, unpublished data).  The phylogenetic analysis suggested that samples from Belize belong in three different clades, which may represent at least three different species.  However, only 26 samples were sequenced from Belize. This study will focus on S. lerneri from two islands of Belize: Carrie Bow Cay and Glovers Reef.  My research will be to further investigate the occurrence of multiple species by increasing the sample size, examining morphology, and sequencing additional genes. In addition to the 16s rRNA gene, two additional mitochondrial genes will be analyzed: the cytochrome oxidase 1 (COI) and cytochrome b (cytb) genes.  The morphology of the samples will be examined by light and confocal microscopy and studied for diagnostic features that distinguish the three genetic lineages in Belize.  The importance of this study is to understand ostracode biodiversity, because they are part of  coral reef and coastal marine habitats, which are being altered by human activity.  In addition, this study will be helpful in understanding speciation in marine habitats and ostracode evolution. The end result of this study will be to conclude whether the three different lineages found in Belize represent distinct species.


Poster #10- Valerie Rodriguez

The significance of salinity for the distribution and development of congeneric sacoglossans (Alderia modesta and Alderia sp.)

Valerie Rodriguez

Department of Biology, California State University, Los Angeles

Sacoglossans in the genus Alderia are specialist herbivores, feeding and settling exclusively on Vaucheria spp., a yellow-green alga found on mudflats along the West Coast of North America. The cosmopolitan species, Alderia modesta, has a southern range limit on the West Coast at San Francisco Bay, while the southern Californian species is found no farther north than Bodega Harbor, CA. I am measuring the viability and reproductive output of the sea slugs and their larvae in different salinities and temperatures. I am also determining whether exposure to Vaucheria spp. from different regions results in varied success of settling, reproducing, and survivorship. Understanding the ecological tolerances of Alderia spp. will give insight into the factors that determine their range limits. 

This preliminary study tested the range of salinities Alderia modesta could tolerate and its reproductive fitness at these salinities. The lecitotrophic larvae were also tested for development ability at varying salinities. The experiments conducted thus far show that Alderia modesta adults are extremely efficient osmoregulators and can survive in salinities ranging from 2 ppt to 32 ppt. However, their reproductive ability seems to be negatively affected as the salinity decreases, which is especially evident at 2 ppt and below. These results suggest the distribution of adult sea slugs is not limited by salinity, but overall fitness may be. Given that global temperatures are changing and estuaries are decreasing in size and health, it is crucial to understand which environmental factors affect the adult sea slugs and their larvae, so as to understand the population distribution, population densities, and potential causes of speciation of the two sea slugs.


Poster #11- Jesus Eduardo Gutierrez


The Three Fundamental Traffic Variables: An Introduction to Traffic Flow

Jesus Eduardo Gutierrez

Mathematics Department
California State University, Los Angeles

The three fundamental traffic variables: velocity, density, and flow are the foundation for research in traffic modeling.  These three fundamental variables are defined as follows: velocity is the rate at which the position changes with respect to time; density is the number of cars per unit of distance; and flow is the number of cars per unit of time.  We assume the existence of a velocity field which assigns a unique velocity u(x,t) to each point in space, x, at each time, t.  The concept of traffic density waves is investigated under the assumption of nearly uniform traffic flow, and the experimental relationship between car velocity and traffic density is given by a nonlinear partial differential equation.  The equation of conservation of cars expresses the relationship between traffic density and traffic flow which is derived by assuming the number of cars is conserved. 




Poster #12- Aidee Gonzalez

Detection of Isomeric BaP Quinones by LC/APCI-MS/MS

 Aidee Gonzalez

The widely spread benzo[a]pyrene (BaP) formed from incomplete combustion processes, such as burning diesel, gasoline, wood, or coal, is a known carcinogen. BaP is removed from the environment by photolysis producing 1,6-, 3,6-, and 6,12-BaP-quinones, but little is known about this photochemical mechanism. To elucidate the mechanism and measure environmental BaP quinones, one must be able to accurately quantify product formation. High performance liquid chromatography/ atmospheric pressure chemical ionization – mass spectrometer (LC/APCI-MS) has proven to be the most sensitive instrument for the analysis of polycyclic aromatic hydrocarbons (PAHs), detecting aromatic acids at 100-400 pg and ketones at 10-100 pg (Letzel et al., Anal. Chem., 73, 1634-45, 2001). The current study presents an extension of this previous work adding unprecedented specificity to this sensitive detection technique, which is invaluable for the analysis of complex mixtures such as real environmental samples. The ion-trap mass spectrometer has the ability to perform very specific MS/MS scans, thus providing signature fragmentation patterns supporting identification of compounds. For quantitative analysis, parent ions can be coupled to specific daughter ions to elucidate the structure for unknown compounds. An optimized method for the LC/APCI-MS/MS means extreme sensitivity and the ability to decipher complex spectra from BaP photolysis or environmental samples with a variety of compounds. The applicability of this method can be extended to test environmental field samples for trace levels of BaP quinones and explore the mechanism of BaP photodegradation in the laboratory.


Poster #13-Angélica López

Career Identity Formation Among Latino College Students. 
Jessica M. Dennis, Angélica López, Delia M. Gutierrez, Cinthya Ramirez, Sonsoles Calderón López, and Jean S. Phinney

Poster #14- Emmanuel Dotsey

The role of Thr 227 and Lys 934 residues in the regulation action of maize phosphoenolpyruvate carboxylase 

Emmanuel Dotsey and Scott Grover 

Abstract: The alteration of the regulatory site of maize phosphoenolpuruvate carboxylase (PEPC) was achieved by performing the point mutations T227V and K934Q. Thr 227 is part of the highly conserved sequence RTDEIRR and has been implicated in the allosteric regulation in PEPC. Lys 934 is part of a mobile loop near the activator site that has recently been elucidated through crystallography. Site directed mutagenesis was used to mutate Thr to Val on residue 227, and Lys to Gln on residue 934. It was hypothesized that since these residues are located in the allosteric site, the mutants were not expected to show any marked loss of enzyme function. Contrary to this, the results showed that both mutants exhibited a complete loss of activity. This result suggest that the hydroxyl group of T227 and the positively charged side chain of K934 both play a very important role in proper enzyme folding through hydrogen bonding and charge-charge interactions.


Poster #15- Patricia Arredondo 

The Development and Validation of a New Measure of PTSD for Young Children

Patricia Arredondo, Faculty Mentor: Mitchell L. Eisen, Ph.D.

California State University, Los Angeles


Project Abstract: There has been a growing interest in understanding the consequences of abuse and trauma in young children. Although recent movements have been made towards the development of more instruments designed to assess symptoms of posttraumatic stress in children, no self-report measures designed to assess trauma symptoms in young children exist. In an effort to fill this need, a new measure has been developed for young children called the Posttraumatic Symptom Inventory for Children (PT-SIC). The measure consists of a 30-item self-report inventory of symptoms of Posttraumatic Stress designed to be used with young children (4-8 years of age), based on the DSM-IV criteria for PTSD. Although data has been previously collected, the primary aim of this study is to collect more validation data for the measure. The researcher hopes to establish psychometric validity.


Poster #16- Julia Aponte

NMR Dynamic Simulation of Xenon’s Diffusion in HPLC Column Material

Julia Aponte, Danny Chagolla, Dr. Errol Mathias and Dr. Yong Ba
Department of Chemistry and Biochemistry
California State University, Los Angeles


Investigation of the molecular dynamics within HPLC columns provides a better understanding of the retention mechanisms that drive the efficiency of separation. Previous studies have utilized variable-temperature dependent 129Xe NMR to characterize the interactions of xenon atoms with the stationary phase of HPLC columns. The resulting spectra map the solvation and diffusion of Xe atoms within and between pores on the surface of the column material. At lower temperatures the dynamic interactions slow down changing the spectra enabling the delineation of these processes by identifying the corresponding peaks. Theoretical dynamic NMR modeling is used to find the kinetics of these processes at various temperatures.  Xe’s kinetic energy varies the rate of diffusion at different temperatures which in turn yields changes in 129Xe NMR lineshape. The theoretical simulation of the dynamic NMR spectra of 129Xe provides a piece of useful information for chromatographic retention mechanisms.



Poster #17- Brian Jacoby

Ethnic Identity as a Predictor of Positive Intergroup Attitudes

Authors: Brian P. Jacoby, Charissa Silva, Jean S. Phinney, & Jessica M. Dennis

Abstract: To examine the relationship between ethnic identity and intergroup attitudes, 713 college freshmen from four ethnic groups were surveyed regarding positive attitudes toward other groups and were assigned to ethnic identity statuses (Phinney, 1992). Those with achieved ethnic identity reported significantly more positive attitudes toward other groups than did those in ethnic identity diffusion and foreclosed. O


Poster #18-


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