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MSD SCHOLARS

STUDENT PROFILES

2007-2008


Mr. Johnny Bontemps
Mr. Ben Lluncor
Ms. Melissa Padilla
Ms. Michelle Palacios
Ms. Angelica Riestra
Ms. Brenda Vazquez

Mr. Johnny Bontemps
Mentor: Dr. Genhong Cheng and Dr. David Sanchez
Major: Biochemistry
Title: HoxB9 in the Interferon-Beta Mediated Anti-viral Response

Johnny Bontemps is a fourth-year Biochemistry major. Since January 2007, he has been working in the lab of Dr. Genhong Cheng in the department of Microbiology, Immunology, & Molecular Genetics under the mentorship of Dr. David Sanchez. The lab focuses on host immune and inflammatory responses to infections, cancers and metabolic challenges. Johnny is studying the mechanisms that control the innate immune response to viral infections.

Type I interferons (IFN), including IFN-β, are a group of cytokine that play an important role in the immune system through their antiviral actions. They are produced and secreted by infected cells. Recognition of viruses by cellular receptors triggers a signaling cascade, leading to the activation of transcription factors such as IRF-3 and NF-κB that subsequently bind to the IFN-β promoter. The focus of Johnny’s research is on the transcription factor HoxB9, recently shown to be involved in IFN-β regulation and anti-viral immunity. His current project involves constructing different expression plasmids of tagged fusion HoxB9, which will provide insights on the movement of the HoxB9 protein in the cell and its interactions with other cellular components. The eventual objective is to identify the components of the signal transduction pathway in which HoxB9 is involved, thus gaining more knowledge about the mechanisms used by the body to fight off viral infections.

After graduating from UCLA, Johnny plans to attend graduate school and to pursue a career in biomedical research. Johnny would like to thank the URC/CARE office, Dr. Genhong Cheng, Dr. David Sanchez, and the Cheng lab for their guidance and support.

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Mr. Ben Lluncor
Mentor: Dr. Harold Monbouquette
Major: Chemical Engineering
Title: Analysis of the lipid synthesis pathway in a thermophilic Archaeon Archaeoglobus fulgidus

Ben Lluncor is a fourth year student majoring in chemical engineering with a biomedical option. He is a first year MSD scholar working in the biotechnology lab of Dr. Harold Monbouquette under the supervision of his graduate student mentor Denton Lai. Ben joined the lab in the summer of his second year.

His laboratory research has been focused on the study of a species of archaea, Archaeoglobus fulgidus. In particular the project is focused on recreating part of the lipid biosynthesis pathway of this organism in E. coli. This is accomplished by expressing two pathway enzymes—GGGPS and DGGGPS—in the lipid synthesis pathway in E. coli and purifying the product. The enzymes further downstream in the archaeal lipid synthesis pathway have not been identified nor has their catalytic function been explained.

These enzymes were identified through gene homology with another thermophilic archaeon, Sulfolobus solfataricus. The genes AF0403 and AF0404 are homologous to the genes that produce GGGPS and DGGGPS in S. solfataricus and were transformed into E. coli. Over expression of AF0403 was achieved. Lack of expression of DGGGPS limits the re-creation of the lipid biosynthesis pathway in E. coli. Further study will be needed to resolve the problem. Ultimately, the entire isoprenoid ether lipid biosynthesis pathway of A. fulgidus will be cloned and expressed in E. coli.

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Ms. Melissa Padilla
Mentor: Dr. Miguel Garcia-Garibay
Major: Chemistry
Title: Towards molecular gyroscopes with a 4,9-Diamantanediyl rotator

Melissa is a fourth year chemistry major. She is a research student working in Dr. Miguel A. Garcia-Garibay’s research group. Melissa’s project is modeled after macroscopic gyroscopes, which are devices used to measure changes in orientation based on the principle of conservation of angular momentum. The simplest model consists of a rotator whose center of mass lies on the spinning axis that is linked to a stator, which provides a rigid frame for the entire system. Melissa is interested in preparing molecular analogs of gyroscopes with bulky stator groups to study the dynamics of the rotation in the solid state and be able to apply the knowledge obtained to the development of molecular machines. She is synthesizing 2,2,5,5-tetrafluoro-bis(triphenylsilyl) bicyclo [2.2.2]octane, a rotor which contains a dipole, and wishes to see if the dynamics of the rotor can be controlled in the solid state with the introduction of the dipole.

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Ms. Michelle Palacios
Mentor: Dr. Peter Bradley
Major: MIMG
Title: The role of the insulinase- like metalloprotease TLN2 in Toxoplasma gondii

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Ms. Angelica Riestra
Mentor: Dr. Sherie Morrison
Major: MIMG
Title: Production of murine-human recombinant IgG3 antibodies against the glucoronoxylomannan (GXM) polysaccharide component of Cryptococcus neoforman's capsule

Angelica Riestra is a fifth year student majoring in Microbiology, Immunology, and Molecular Genetics (MIMG). She is conducting research in the laboratory of Dr. Sherie Morrison under the mentorship of Kileen Mershon. Angelica started working in the Morrison lab during the summer following her sophomore year. One of the lab’s main areas of research is to develop a better understanding of antibody structure and function, and the application of this knowledge to construct recombinant mouse–human chimeric antibodies with possible therapeutic use.

Cryptococcus neoformans is an opportunistic fungus that causes life-threatening meningitis in immunocompromised persons, especially those infected with HIV. The available treatments are not effective since 10-20% of treated individuals still die from the disease and treatment in AIDS patients does not eradicate the infection. Passive antibody (Ab) therapy is an alternative treatment that has shown promise, with mouse IgG1 extending the life-span of C.neoformans-infected mice. Preliminary studies in the Morrison laboratory found that a mouse-human chimeric IgG3 also extended the survival of BALB/c mice infected with C. neoformans and C57BL/6J mice infected with Cryptococcus gatii when the antibodies were administered as immune complexes and at lower doses than other studies. In order to determine the unique characteristics of IgG3 that may contribute to this previously unreported protection, Angelica’s project has involved the construction, purification, and characterization of two mutant mouse-human IgG3 chimeric antibodies against the glucoronoxylomannan (GXM) polysaccharide component of C. neoformans capsule. One Ab contains an N297Q mutation in the C H2 region which will prevent the antibody’s glycosylation. The other Ab had the long hinge region, characteristic of IgG3, replaced with a shorter IgG1 hinge. After Angelica has purified a sufficient amount of each mutant antibody she will test their effects against Cryptococcus infection in-vivo. The study of these antibodies should provide insight about the role that glycosylation and the hinge region play in activating effector functions and the mechanisms involved in IgG3-mediated protection against Cryptococcus.

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Ms. Brenda Vazquez
Mentor: Dr. Mayumi Prins
Major: MCDB
Title: Testing abnormalities in Mesenchymal Stem Cells and their role in Autoimmune Diseases

Brenda Vazquez is a 5th year Molecular, Cell and Developmental Biology major. She has been conducting research under the guidance of Dr. Mayumi Prins in the Neurosurgery Department. Brenda has been doing research since she was a 2nd year student, but has been in Dr. Prins lab since the start of her fifth year.

Traumatic Brain Injury (TBI) is sustained by approximately 1.4 million in the United States each year. Of particular concern is TBI among children who participate in sports, because of their ongoing neurological development. Following TBI cerebral pathophysiology can be severely affected due to ionic shifts, release of excitatory neurotransmitters, and change in cerebral metabolism. During the acute phase (≤1 hr) after TBI there is a transient increase in cerebral metabolic rates for glucose (CMRglc) (Hovda et al. 1994; Sutton et al. 1994; Yoshino et al. 1991). There is speculation that this initial increase in CMRglc is due to increased cellular energy required to restore ionic balance and maintain the neuronal membrane potential (Hovda et al. 1990, 1991, 1996). Age-related changes in CMRglc were revealed with fluid percussion injury in postnatal day 17 (PND17) (Yoshino et al. 1991). Suckling rats showed immediate increase in CMRglc of the ipsilateral cortex, but the extent of the CMRglc depression was truncated relative to adults (Thomas et al. 2000). These age-related changes in CMRglc are due to various changes of metabolic substrates and enzymes. In this study, we will see the nicotinimide adenine dinucleotide (NAD+ ) and glyceraldehde phosphate dehydrogenase (GAPDH ) activity following controlled cortical impact (CCI) injury in PND 35 and PND90 rats, which contribute to this acute metabolic dysfunction

 

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Profiles of Students