Life Sciences Commons^™

Characterizing Ntrc-Like Activators Affecting Myxococcus Xanthus Development, Jessica Eisenstatt

Honors Capstone Projects - All

Myxococcus xanthus is a soil bacterium that is a member of a group of organisms known as the myxobacteria. M. xanthus cells live in biofilms and feed on other bacteria to obtain nutrients. During times of inadequate nourishment, M. xanthus cells aggregate, build fruiting bodies, and fruiting body cells differentiate into spores that are highly resistant. In order to form the fruiting bodies, M. xanthus cells must be able to move across solid surfaces. There are two motility systems, the adventurous system (A-motility) and the social system (S-motility), used by M. xanthus cells to navigate across surfaces. The adventurous system …

Clonogenicity Of Human Promyelocytic Leukemia Cells Enlarged And Multinucleated By Treatment With Cytochalasin B And Their Potential As Targets For Improved Chemical And Physical Therapeutic Approaches, Shannon Dubois

Honors Capstone Projects - All

Cytochalasin B (CB) is a pharmacological agent produced by fungi that disrupts the actin microfilament cytoskeleton and inhibits cytokinesis. It interferes with the formation of the contractile ring and with the development of the cleavage furrow, thus preventing cell division. When normal cells are treated with CB, cell cycle arrest occurs. However, when neoplastic cells are treated with CB, the cells continue to enter the cell cycle and to make new nuclei, but since cytokinesis cannot occur, the neoplastic cells become enlarged and multinucleated. Our lab proposes that enlarged multinucleated neoplastic cells might be more susceptible to agents damaging DNA …

Compensation Mechanisms For Altered Membrane Sterol Compositions In The Yeast: Saccharomyces Cerevisiae, David M. Dewolfe

Honors Capstone Projects - All

Cell Membranes are composed of several different lipid and sterol products. Among these are, chiefly, phospholipids, glycolipids, sphingolipids, various proteins and sterols. The sterol that is prevalent in fungi, including yeast, is ergosterol. It plays the same physiological role as cholesterol in mammalian cells. That is, mainly, to control membrane fluidity. Membranes in general are extremely important to the normal functioning of any cell and its sub-cellular compartments. The primary factor in the normal functioning of a membrane is the relative composition of the previously mentioned components. Even though there is a high amount of traffic between different membranes within …

The Role Of Estrogen Receptor Beta In Neonatal Oocyte Development, Kelsey E. Breen

Honors Capstone Projects - All

Establishment of the pool of primordial follicles is essential for reproduction. Shortly after their formation, female germ cells undergo a series of incomplete cell divisions resulting in clusters called cysts. After birth, mouse germ cell cysts break down into individual oocytes (a process referred to as cyst breakdown) that are surrounded by somatic pre-granulosa cells to form primordial follicles. During the process of cyst breakdown, a subset of oocytes in each cyst dies with only a third of the initial number of oocytes surviving. The mechanisms controlling cyst breakdown and programmed cell death are unknown. Previous studies have focused on …

Characterization Of Hypersensitive Response Related Genes Of Arabidopsis Thaliana, Keluo Yao

Honors Capstone Projects - All

Like most complex living organisms, plants have many mechanisms to prevent disease by microbial pathogens. One of the most important and well developed defense systems that involve recognition, identification and systematic response is the hypersensitive response.

The hypersensitive response is a complex, early defense response against pathogens that causes necrosis and cell death at the site of infection to restrict the spread of pathogen. Hypersensitive response is a type of programmed cell death, and its activation usually happens when the plant recognizes a pathogen through an elicitor. This recognition triggers a series of signal transductions events which end in the …

Genetic Analysis Of Germline Development In The Model Organism C. Elegans, Kaitlyn A. Wurz

Honors Capstone Projects - All

My research investigated the relationships among several transcriptional and/or post-transcriptional regulators in the C. elegans germ line. I examined the relationship between the rha-1 gene and three other regulatory genes, ego-1, glp-1 and csr-1. These genes function in germline proliferation and differentiation and are required for fertility. Because these genes regulate similar processes, we have investigated the relationships among them. The rha-1 gene encodes an RNA helicase that is required for germline development, chromatin regulation, and RNA interference (RNAi). The ego-1 gene encodes an RNA-directed RNA polymerase that is also required for these processes. Although many of the rha-1 and …

Molecular Analysis Of Arabidopsis Thaliana Genes Involved In Stress Response, Jessica M. Whitlock

Honors Capstone Projects - All

Arabidopsis thaliana is an excellent model plant to study various plant processes, including plant’s response to environment, its interactions with other organisms, etc. In this study I characterized eight Arabidopsis genes that are likely to regulate plant’s responses to biotic and abiotic stresses. Microarray analysis was done previously in our lab to identify Arabidopsis genes that are differentially expressed in response to various biotic and abiotic stresses and several plant hormones. The biotic stresses include bacterial, fungal and viral pathogens (both virulent and avirulent strains), sucking and chewing insects. The abiotic stresses include chemicals that induce variety of oxidative stresses …

Characterization Of Type Ii Secretion Mutants Of Pseudomonas Aeruginosa, Sijung Suh

Honors Capstone Projects - All

Pseudomonas aeruginosa mutants PA0686, PA3102, PA3103, and PA5210 carry transposon insertions in uncharacterized genes in the PA01 background. The biofilms formed by these mutants show different phenotypes than PA01, their wild-type counterpart. BLAST searches and phylogenomic mapping tools indicate that protein products of the mutated genes are involved in P. aeruginosa type-II secretion, which is linked to twitching motility. In this study, 96-well microtitre plate biofilm assays, UV/visible spectrophotometer analysis, and motility assays were used to demonstrate a link between type-II secretion, twitching motility and biofilm formation. The results show that the PA5210 mutant forms a biofilm that is less …

Root Production And Herbivory In An Upland Grassland Community In Yellowstone National Park, Anna M. Stewart

Honors Capstone Projects - All

Few investigations have been conducted on belowground plant consumption and production due to the difficulty of examining root systems over time without significant disturbance. In most field studies, roots are sampled monthly, a time interval that cannot capture the rapid growth and death of fine roots. The purpose of this study was to estimate rates of root production (growth) and consumption in an upland grassland inYellowstoneNational Park. Root lengths were digitized in four minirhizotron tubes, four times per month (at three-day intervals over ten days) from May - September 2005. I attributed root length that disappeared over each three-day period …