Hood College Student Works

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INTERACTIONS BETWEEN GALACTOSE REPRESSOR PROTEIN (GALR) AND THE ALPHA SUBUNIT OF RNA POLYMERASE: REPRESSION AND ACTIVATION OF THE gal PROMOTERS
(1995-12) Hanger, Robert R.; Hood College Biology; Biomedical and Environmental Science
To study molecular mechanisms of gene regulation at the level of transcription, the gal operon of Escherichia coli was used as a model system. Two overlapping promoters P1 and P2 separated by 5 bp and located on opposite faces of the DNA double helix control transcription of galETKM. DNA templates for in vitro transcription experiments were constructed in order to study protein-protein interactions between the repressor GalR, binding at the external operator OE, and the C-terminal domain portion of the alpha subunit of RNA polymerase (α-CTD) binding at gal promoters under non-looping conditions. Partial repression mediated by GalR was quantitated on mutant templates that had only the Pt promoter intact. Activation mediated by GalR was established on mutant templates that had only the P2 promoter intact. Templates were also constructed to alter the geometry between OE and gal promoters. It was shown that GalR mediated repression occurs at either promoter provided GalR binds at OE located on the same face of the DNA double helix as RNA polymerase binding at the promoter, and it was determined that activation occurs at either promoter provided GalR binds at OE located on the opposite face of the DNA with respect to RNA polymerase. Transcription experiments were then performed using mutant RNA polymerases with tryptophan substitutions at sites from amino acids 261 to 270 of α-CTD). It was shown that the same region on α-CTD known to interact with cAMP receptor protein (CRP) at Class I CRP dependent promoters, and with the UP regulatory element at rrnBP, also interacts with GalR when bound at OE, or interacts with DNA near OE, and that it is this interaction that is responsible for GaIR mediated control of transcription. It is proposed that α-CTD may interact with a 3rd DNA regulatory element overlapping OE, and thus stimulate transcription from galP2. Partial repression at the galP1 promoter may be the result of GalR preventing this interaction, by repositioning α-CTD to a site further downstream, to a location where open complex formation is not favored. Alternatively, activation and repression may be due to conformational changes in RNA polymerase induced by protein-protein interactions between α-CTD and GaIR.
CALORIE RESTRICTION AND ENDOMETRIOSIS: IS THERE A PROTECTIVE FUNCTION?
(2003-09) Handy, April M.; Hood College Biology; Biomedical and Environmental Science
Endometriosis, defined as the presence and proliferation of endometrial tissue outside the uterus, affects up to 20% of women of reproductive age and can cause severe pelvic pain and infertility. It is well known that endometrial tissue proliferates under the influence of estrogen and that inflammation is most severe when circulating levels are high (late follicular phase of the menstrual cycle). The mechanism(s) leading to the implantation and proliferation of ectopic endometrial tissue in some women, while re-absorption occurs in others, is not known. Current therapy for the disease focuses on controlling the production of estradiol, and in some cases, inhibiting it completely along with reducing the ectopic tissue with periodic abdominal surgery. Understanding the mechanism(s) underlying the initiation and progression of endometriosis may allow for the development of less invasive, targeted therapies. Hypothetically, the incidence and/or progression of proliferative diseases, such as endometriosis, could be reduced if the overall rate of cellular proliferation could be controlled. Calorie restriction (CR), a nutritional intervention that extends lifespan and retards age-related disease in a variety of short-lived species, has been shown to reduce proliferation in lymphocytes as well as liver and mammary tissue. Calorie restriction has also been shown to reduce both spontaneous and induced forms of cancer in rodents. A preliminary report from the Institute on Aging (NIA) longitudinal study of CR in nonhuman primates showed a reduced incidence of naturally occurring endometriosis in CR vs. ad libitum (AL) female rhesus monkeys (22.6% and 11.1%, respectively). Assessment of the entire colony will not be available for many years due to the longer than thirty-year lifespan of rhesus monkeys. Therefore, the purpose of this study was to begin to examine the possible protective function(s) of CR against proliferation of extrauterine endometrial tissue in an established, short-lived model of rat endometriosis. In this study, forty female Fisher 344 rats were divided into two groups: ad-libitum fed (AL) and calorie restricted (CR) that received 40% fewer calories. Half of the animals in each diet group underwent abdominal surgery during which one uterine horn was removed, divided, and autotransplanted onto alternating descending arterial cascades in the mesentery surrounding the small intestine. Sham-operated animals in both diet groups served as controls. The implants were allowed to remain for five to six weeks and were compared for growth during a second abdominal surgery. Body weight was significantly lower in the CR group as was the weight of the remaining intact uterine horn at the time of the second surgery. The percentage of endometrial implants surviving at five to six weeks was not significantly different between the two diet groups. The overall growth of implanted tissue was higher in the CR group. This preliminary investigation produced no clear evidence that proliferation of uterine tissue is slowed by the proposed dietary intervention. Although the results gathered in this study do not confirm our original hypothesis, there are other aspects of endometriosis, primarily the attachment process, which remain to be explored.
ROLE OF VP40 IN EBOLA ASSEMBLY
(2001-06) Hamilton, Elaine; Hood College Biology; Biomedical and Environmental Science
The VP40 protein of Ebola virus (EBOV) is thought to be a key component in the assembly of infectious virions. If so, one might predict that when expressed alone, it would form virus-like particles. To test this possibility, we created a plasmid that expressed VP40 under the control of a CMV promoter. Transfection of mammalian cells with this construct showed that VP40 was synthesized as a single protein species that was eventually released into the culture medium. Pulse-chase experiments demonstrated that VP40 protein expressed alone had a rate of release that was comparable to infectious EBOV. Further analysis of the culture medium by density gradient centrifugation revealed that VP40 was released as two distinct forms: one with a density similar to that of authentic virions (1.15 g/cm³) and one with a density consistent with lipid membranes (1.05 g/cm³). Deletion mutants of VP40 identified areas within the protein that are necessary for the protein to mediate its release from cells. EM and immuno-EM studies of VP40-transfected cells showed that VP40 localized at or near the plasma membrane where it induced proliferation, or "ruffling", and formation of empty liposomes. These data suggest that VP40 has the capacity to associate with the host-cell plasma membrane and cause evaginations that are released from the cell as liposomes in the absence of the other viral components. However, with further investigation, we now know that this is not entirely true. VP40 does bind to the surface of the cell and induces proliferation, but the liposomes and "free" protein released from the cells are merely artifact. Electron microscopy (EM) of both isopycnic gradient peaks reveals fib -particles in the light peak and seemingly no particles in the heavy peak. However, additional isopycnic gradients in which the culture media was pre-treated with trypsin eliminated the light peak, and showed the small amount of VP40 protein in the heavy peak was resistant. This suggests that the particles seen in the light peak are artifact of EM or the sucrose gradient. In fact additional experiments show that VP40 is extremely inefficient in budding; rather plays a role in ruffling for viral pre-assembly.
SURVEY FOR ASBESTOS-CONTAINING MATERIALS (ACM) IN SELECTED BUILDINGS OWNED BY THE STATE OF MARYLAND
(1989-05) Halpin, Verna Lee; Hood College Biology; Human Sciences
Epidemiological and animal studies have established that asbestos is a carcinogen. Recognition of the health hazards and widespread use of asbestos-containing materials (ACM) in building construction has generated concern for exposure of building occupants to asbestos released from ACM. The State of Maryland conducted a state-wide survey to identify the presence and condition of ACM in over 3,000 buildings. Bulk samples of suspected ACM were collected and analyzed for asbestos content by polarized light microscopy with dispersion staining. An algorithm was used to score each building for potential asbestos exposure and to prioritize buildings for corrective action. Thirteen buildings were examined for the severity of asbestos contamination using the State of Maryland's model.
CHRONIC HIV INFECTION: DEVELOPMENT AND CHARACTERIZATION OF CHRONIC INFECTION MODEL SYSTEMS FOR THE EVALUATION OF ANTIVIRAL AGENTS
(1994-05) Halliday, Susan; Hood College Biology; Biomedical and Environmental Science
Millions of people worldwide are infected with human immunodeficiency virus (HIV). Latent HIV disease in infected patients is characterized as an asymptomatic phase which can last for over 10 years. Recent studies have shown that virus replication in lymphoid tissues from HIV-infected patients continues at a high level throughout the clinically latent phase. Useful model systems of the latent stage of HIV disease in vivo need to be developed to evaluate therapeutic agents which could be of help to the vast number of infected individuals. Several in vitro model systems of latent HIV-infection (i.e., U1, ACH2, OM10.1) have been developed and utilized in the study of chronic/latent HIV infection. Cell lines of this type have been used to investigate the role of inductive and inhibitory signals on HIV replication. However, a good model in vitro system for evaluating agents capable of reducing the infected cell population or inhibiting the spread of virus from cell to cell is currently unavailable. Such cell-based models could be of tremendous value in the study of chronic/latent HIV infection. Little is known about the biological characteristics of chronically infected cell lines. The purpose of this project was to develop model systems of chronically infected cell populations in order to characterize the chronic state of HIV infection in vitro. Once these model systems were established, a group of antiviral agents with diverse mechanisms of action were evaluated. This evaluation included their effect on virus production and their ability to inhibit virus spread by cell-to-cell transmission. Populations of chronically infected MT2, CEM-SS, H9, U937, and CEM-CCRF cells were derived as part of this study. These chronically infected cell populations were biologically and biochemically evaluated in order to define and characterize the infected cells and to compare them with parental uninfected cells. It was determined that the chronically infected cell populations derived from cytopathically infected MT2 and CEM-SS cells include a larger population of nonproductively infected cells than of productively infected cells. Cells derived from noncytopathically infected H9, U937, and CEM-CCRF cells yielded a population of cells which were predominantly productively infected. These chronically infected cells thus served as good models of chronic HIV infection since they continuously produce virus in the absence of any associated cytopathology. A panel of antiviral agents with diverse mechanisms of action was evaluated to determine their effects on chronic HIV infection and the cell-to-cell spread of virus using these cell-based model systems. One compound, SRI 7755, was identified in these studies that was capable of significantly reducing the number of infected cells in a chronically infected population as well of inhibiting the induction of virus expression in latently infected U1 cells. The major goal of this project was to develop and characterized chronically HIV infected cell lines. The identification of compounds effective in inhibiting or suppressing virus production in these chronically infected cell populations was also demonstrated.
Increased Resistance to Cytomegalovirus in Graft-versus-Host Immunosuppressed F1 Mice by Pre-Immunization
(1986-05) Hallam, John A.; Hood College Biology; Biomedical and Environmental Science
Graft-versus-host (GvH) immunosuppression was induced in (C57BL/10xB10.A)F1 hybrid mice by intravenous inoculation of 30x10⁶ parental (B10.A) spleen cells. This treatment caused the normally resistant F1 mice to become highly susceptible to cytomegalovirus (CMV) challenge delivered 7 or 14 days later (survival below 10%). This susceptibility was reversed by immunization with live CMV by either intraperitoneal (i.p.) or subcutaneous route prior to GvH immunosuppression and challenge (survival greater than 87%). Mice which were immunized by the i.p. route and subsequently immunosuppressed without then being challenged had significantly higher mortality due to recrudescent CMV infection than similarly treated mice that did receive a challenge. These data suggested a boosting effect of the challenge in immunized mice. In vitro cell mediated responses to trinitrophenyl (TNP) modified self and allogeneic histocompatibility antigens were abrogated in all GvH groups 10 days after parental cell inoculation which demonstrated that GvH immunosuppression was reversed only for CMV. The CMV specific humoral antibody (Ab) response was monitored using an enzyme linked immunosorbent assay (ELISA) method. The CMV was highly immunogenic in pre-GvH F1 mice as demonstrated by a rapid rise in IgG Ab titer. In GvH immunosuppressed mice, the titer peaked after parental cell administration and then declined rapidly. The titers were high at the time of challenge and specific Ab may have contributed to defense against challenge. The effect of the post GvH challenge in preventing recrudescent CMV infection could not be explained in terms of protecting Ab since titers declined in both cases.
Assessing School-Related Anxiety Levels and Self-Efficacy Among First-Generation College Students
(2024-12) Chamberlin, Casey; Gupta, Sangeeta; Kundey, Shannon; Gricus, Michelle; Hood College Department of Psychology & Counseling; Departmental Honors
Current research on student success suggests that first-generation college students (FGCS) experience worse academic outcomes, and greater barriers to success compared to their continuing-education peers (Dennis et al., 2005; Koh et al., 2022). There is also a body of literature on how various student factors, such as anxiety and self-efficacy, drive student success (Barrows et al., 2013; Kumari & Jain, 2014). When a student specifically experiences school-related anxiety and does not believe in their ability to perform well in the classroom, this could impact their academic outcomes. The present study aims to examine the extent to which FGCS struggle with school-related anxiety and self-efficacy versus their continuing-education peers. The present study assessed anxiety and self-efficacy in 170 undergraduate first-year students, 38% of whom were FGCS, using the anxiety subscale of the Learning and Study Skills Inventory (LASSI), the Revised Test Anxiety Scale, and an Academic Self-Efficacy Scale. FGCS students reported significantly higher anxiety levels based on their LASSI scores. However, FGCS were not significantly different than their non-FCGS peers in their test anxiety or self-efficacy, as revealed by independent samples t-tests. Additionally, there were significant negative correlations between self-efficacy and test anxiety as well as between self-efficacy and LASSI anxiety across all students. Implications for FGCS, school-related anxiety, and self-efficacy are discussed.
Communities of Practice: How Teachers' Relationships Underscore Suburban Middle School Culture and Organizational Commitment
(2024-12) Sutherin, Kristen G.; Locraft Cuddapah, Jennifer; Harris, Keith; Markoe, Michael; Hood College Organizational Leadership; Doctor of Organizational Leadership
Teacher attrition poses significant challenges in education systems, leading to inconsistent instruction, reliance on substitute teachers, and increased costs for hiring and training replacements (Carver-Thomas & Darling-Hammond, 2019). Despite considerable research on this issue in various educational settings, a gap exists in understanding the factors influencing teacher commitment specific to suburban middle school teachers. Drawing from theories on communities of practice (Lave & Wenger, 1991), organizational commitment (Allen & Meyer, 1990), and cultural frameworks (Schein & Schein, 2017), this multiple case study of middle school teachers explored how school culture impacted their commitment to their schools and districts. The central research questions focused on the influence of school culture on organizational commitment; the elements of culture manifested in artifacts, beliefs, and assumptions; and the effects of team, school, and district cultures on teacher commitment. Additionally, the study examined how relationships within these contexts shape teacher commitment and explored the costs and benefits associated with sustaining commitment. Data procedures involved distributing questionnaires to general education teachers across four suburban middle schools followed by in-depth, semi-structured interviews with selected participant volunteers (Creswell & Creswell, 2018). Key themes emerged, highlighting the significance of relationships and trust in fostering commitment, the overall culture of the school, the role of leadership support and stability, and the ultimate decision to stay or leave. Study findings underscored that neglecting culture and commitment issues could exacerbate teacher attrition, necessitating continual investments in new teachers and depriving students of the stability and expertise that experienced teachers provide. Teachers want to stay in schools where they feel a sense of belongingness which leads to organizational commitment. To address these challenges, recommendations include ensuring teachers begin to connect and build relationships within their schools, creating communities of practice for school leaders to share best practices, minimizing principal attrition and movement year to year, establishing opportunities for teachers to engage with district leaders, and building trust and respect through clear communication. By prioritizing these strategies, educational stakeholders can work toward operational excellence and mitigate teacher turnover, ultimately ensuring a more stable and enriching learning environment for students in suburban middle schools.
Conflict as the Accelerant of Social Change
(2024-11) Rogers, Cameron; Verzosa, Noel; Dodman, Trevor; Campion, Corey; Hood College English & Communication Arts; Humanities (M.A.)
Even as humanity has advanced and become “civilized” over its existence, conflict clings to it in varying scopes and impacts. The changing power of war, conflict, and bloodshed stretches far and wide, from benefits like medical advancements to its numerous detriments of killing, destruction, and crimes against humanity. While most conflicts are regarded as tragedies and needless bloodshed, they still spur change through the actions taken during or after their occurrence. Some small-scale conflicts can spark massive social changes, such as the Wounded Knee Occupation of 1973. Other conflicts can lead to gradual changes in perception about war and its necessity, such as the Wars in Vietnam and Iraq. In my portfolio, I will examine conflict’s ability to accelerate social change through specific engagements, arguing that it can serve as a harsh but necessary tool for societies to advance and to right past wrongs.
AMYLOID PLAQUES IN CHRONIC WASTING DISEASE
(1990-09) Guiroy, Don C.; Hood College Biology; Biomedical and Environmental Science
Chronic wasting disease (CWD), a progressive neurological disorder of captive mule deer and Rocky Mountain elk, is characterized neuropathologically by widespread spongiform change of the neuropil, intracytoplasmic vacuolation of the neuronal perikarya and astrocytic hypertrophy and hyperplasia. Histochemically demonstrable amyloid plaques and amyloid plaques reactive to antibodies prepared against scrapie amyloid in captive mule deer, mule deer hybrids and Rocky Mountain elk naturally affected with CWD are presented. Amyloid plaques in CWD-affected mule deer were congophilic, birefringent and periodic acid-Schiff (PAS) positive. In mule deer hybrids, only occasional PAS-positive plaques were observed. No histochemically demonstrable plaques were observed in CWD-affected Rocky Mountain elk. Antibody raised against scrapie amyloid showed robust immunoreactivity with amyloid plaques in CWD-affected captive mule deer and were found in the cerebral grey and white matter in clusters or in isolation, in deep subcortical nuclei, in all layers of the cerebellum, in areas of extensive vacuolation and in subpial and perivascular regions. In hybrid deer, plaques were rarely observed in cerebellum and subpia. A notable finding in brain sections of CWD-affected hybrid deer and Rocky Mountain elk was a circumscribed collection of scrapie amyloid-immunopositive nuclei with non-congophilic, non-birefringent amyloid deposits located at its center. In elk, plaques were not observed in cerebellum, subpia and subependyma. Furthermore, amyloid plaques in CWD-affected captive mule deer were alcianophilic at 0.3 M magnesium chloride indicating the presence of weakly to moderately sulfated glycosaminoglycans. Similar scrapie amyloid-immunoreactive plaques are also present in Creutzfeldt-Jakob disease, Gerstmann- Straussler syndrome and kuru in humans. The data presented here corroborate that CWD belongs to the subacute spongiform virus encephalopathies (transmissible cerebral amyloidoses).
SIGNIFICANT FACTORS, ISSUES, AND THE ROLE OF POPULAR FORCES INVOLVED IN THE PASSAGE OF THE VOTING RIGHTS ACT OF 1965 IN THE UNITED STATES SENATE
(1987-05) Guilfoyle, Jean Marie; Hood College Counseling, Care and Interdisciplinary Studies in Human Behavior; Human Sciences
AMMONIA AND NITRATE UPTAKE KINETICS BY THREE SPECIES OF AQUATIC VASCULAR PLANTS
(2007-12) Guedes, Marcia; Hood College Biology; Biomedical and Environmental Science
THE DEVELOPMENT OF A WESTERN BLOT (IMMUNOBLOT) ASSAY FOR THE DETECTION OF IgG AND IgM ANTIBODIES TO TREPONEMA PALLIDUM IN HUMAN SERUM
(1996-12) Gross, Robert W.; Hood College Biology; Biomedical and Environmental Science
A Western Immunoblot assay was developed to detect IgG and IgM antibodies to Treponema pallidum, the causative agent of Syphilis, in human serum. A total of 220 human serum samples and 3 cerebral spinal fluid samples were run on the Syphilis Western ImmunoBlot (SWIB) IgG assay and the Fluorescent Treponemal Antibody Absorption (FTA-ABS) assay to determine relative sensitivity, specificity and accuracy. High specificity for the 14, 15 and 48 kDa antigens was demonstrated with FTA-ABS positive samples versus FTA-ABS negative samples. The development of only one of these three bands in the SWIB IgG assay was indicative of a positive sample. Sensitivity, specificity and accuracy were checked further by running 30 human serum samples from a well-defined CDC syphilis panel and 14 potentially cross- reactive autoimmune samples on the SWIB IgG assay. The sensitivity, specificity and accuracy for all 267 samples were 97.4% (111/114), 98% (150/153) and 97.8% (261/267), respectively. A total of 151 human serum samples were tested on the SWIB IgM assay and a commercially available Syphilis IgM Capture ELISA to determine relative sensitivity, specificity and accuracy. A lack of specificity with the 37 kDa antigen was demonstrated. Overall, very few bands were visualized on IgM blots and no definitive positive cut-off was evident. Three samples were equivocal by ELISA and were not included in the calculations. The sensitivity, specificity and accuracy of the SWIB IgM assay were checked further by running 14 potentially cross-reactive autoimmune samples. With the appearance of one band other than the 37 kDa antigen band as indicative of a positive, the sensitivity, specificity and accuracy for 162 samples tested were 46.7% (14/30), 84.8% (112/132) and 77.8% (126/162), respectively. Immunochemical analysis of separated Treponema pallidum antigens immobilized on nitrocellulose strips was conducted using mild periodate oxidation to identify any carbohydrate moieties. The 31, 34 and 41 kDa antigen bands lost reactivity with mild periodate oxidation compared with control strips. These antigens are possible glycoproteins of Treponema pallidum.
THE DEVELOPMENT OF AN ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA) FOR THE DETECTION OF IgG AND IgM ANTIBODIES TO LEGIONELLA PNEUMOPHILA SEROGROUPS ONE THROUGH SIX
(1993-12) Gross, Catherine S.; Hood College Biology; Human Sciences
An enzyme linked immunosorbent assay (ELISA) was developed for the detection of IgG and IgM antibodies to Legionella pneumophila serogroups 1 through 6. The ELISA compared favorably with the L. pneumophila serogroup 1 through 6 Indirect Fluorescent Antibody (IFA), the current serological method of choice. Two clinical comparisons were conducted to evaluate the performance of the LEGIONELLA ELISA assay relative to the IFA method for detection of IgG and IgM antibodies to L. pneumophila. In the first comparison, a total of 203 clinical specimens were tested in the ELISA and resulted in specificity, sensitivity, and accuracy percentages of 93.0%, 99.4% and 98.0%, respectively, when qualitatively compared to the IFA method. The second clinical comparison was performed by personnel at Maryland Department of Health using the LEGIONELLA ELISA and was based on a collection of samples primarily from the Legionella outbreak in Western Maryland. LEGIONELLA ELISA results indicated 100% sensitivity, 94.115 specificity and an overall accuracy of 95% when qualitatively compared to the IFA method. The specificity of the LEGIONELLA ELISA was further challenged by evaluation of 94 potential cross reactive sera that included other Legionella app., mycoplasma, chlamydia and syphilis specimens. Cross reactivity was observed in the LEGIONELLA ELISA in one L. micdadei specimen with a confirmed negative L. pneumophila IFA titer. A selection of these antisera were additionally evaluated by western immuno-blot analysis in an effort to detect potential cross reactive proteins. Detection of significant increases in antibody against L. pneumophila is critical to diagnosis by the IFA method. Such detection was assessed in the LEGIONELLA ELISA using 131 paired acute and convalescent sera. The ELISA demonstrated a 100% sensitivity, 98.9% specificity and an overall accuracy of 99.2% in detection of significant increases in antibody titer. Paired acute and convalescent sera from four individuals with diagnosed legionellosis were evaluated by western immuno-blot analysis in an effort to define the immune response to L. pneumophila antigens. Differences in the IgG and IgM immune responses were apparent. An IgG only seroconversion was clearly demonstrated in one individual. Monoclonal antibodies specific to the 58 kDa heat shock protein, 24 kDa Mip and common lipopolysaccharide epitopes were used as markers in the western immuno-blots. Periodate oxidation was performed on L. pneumophila serogroup specific antigens to determine the participation of carbohydrate moieties in the serologic reactivity of selected L. pneumophila positive antisera. Monoclonal serogroup specific anti-lipopolysaccharide antibodies were used in the periodate oxidation experiments to verify the effectiveness of various concentrations of periodate on carbohydrate epitopes. Sensitivity to periodate was indicated in the ELISA for all serogroups by percent absorbance reductions in the binding of the monoclonal and polyclonal antisera when compared against the absorbance of the controls. Periodate oxidation was additionally performed on transblotted L. pneumophila serogroup specific antigens in an effort to characterize the effect of periodate on serogroup specific and common epitopes and to possibly identify periodate sensitive antigens. Some sensitivity to periodate was indicated in the western immuno-blot analysis by absence of banding. In overall performance, the LEGIONELLA ELISA compared favorably with the IFA method and will be a rapid and reliable objective alternative for detection of IgG and IgM antibodies to L. pneumophila.
QUANTIFICATION OF PHOTODIMERS FROM ULTRAVIOLET RADIATION-INDUCED DNA DAMAGE IN THE SEA ANEMONE, AIPTASIA PALLIDA USING ENDONUCLEASE SENSITIVE SITES (ESS)
(2011-05) Griebel, Jessica M.; Hood College Biology; Biomedical and Environmental Science
Tropical littoral zones offer biologically harmful environments to marine invertebrates due to high levels of exposure to ultraviolet radiation. I documented the extent of DNA damage in the sea anemone Aiptasia pallida under laboratory conditions by applying UVR to live animals as well as pooled DNA that had previously been extracted from A. pallida. Cultured A. pallida from Walsingham Pond, Bermuda were subjected to varying lengths of UVR exposure to quantify DNA damage in the form of number of cyclobutane pyrimidine dimers (CPD's). An endonuclease was applied to those treated with UVR to determine varying amounts of DNA damage. Samples without endonuclease were more significant compared to those treated with endonuclease. Overall, all treatments were not statistically significant at the 0.05 alpha level. Small sample sizes and the inability to extract DNA efficiently without causing damage to the controls, were not found to follow a specific pattern.
Effects of Diazinon and Diazinon-HC1 Reaction Mixture On Acetylcholinesterase Activity In the Brain and Blood Plasma Of Rainbow Trout (Salmo gairdneri)
(1978-07) Greene, Sefronia Ann; Hood College Biology; Human Sciences
Rainbow trout (Salmo gairdneri) were exposed to various concentrations of diazinon and diazinon-HC1 reaction mixture over a 64 hour period during which time the brain and blood plasma of the fish were analyzed for acetylcholinesterase (AChE) activity. The fish were placed into glass jars containing 14 liters of well water and were sampled at 4, 8, 16, 32, and 64 hours time periods; there were five treatments per time period and three replicates per treatment. The treatments consisted of a positive control, a negative control and three concentrations of diazinon or diazinon-HC1 reaction mixture. Test concentrations for diazinon were 0.1, 0.56, and 1.0 ppm., and 0.01, 0.032, and 0.056 70 volume for the diazinon-HC1 reaction mixture. The data collected indicated that the rate of absorption of diazinon and diazinon-HC1 reaction mixture increased rapidly during the first 16 hours and for the most part, remained at or near this level throughout the duration of the remaining test periods. However, the trout were more sensitive to the residual toxicity (due to an AChE inhibitor) in the diazinon-HC1 reaction mixture than to the diazinon. This was indicated by a 504 kill in the test population over a 64 hour period in the reaction mixture as opposed to 1870 mortality over the same period with diazinon.
SOME LEGAL ASPECTS OF NON-MARITAL COHABITATION
(1974-07) Graf, Catherine K.; Hood College Psychology; Human Sciences
Non-marital cohabitation, on college campuses in particular, has been of professional interest recently, with ongoing research concentrated on the prevalence of cohabitation, the social factors leading to cohabitation, characteristics of the relationship, problems experienced, and the effect of cohabitation on the individuals involved, on their relationship to each other, and on society. At the Groves Conference on Marriage and the Family at Myrtle Beach, South Carolina, on May 10-13, 1973, persons who were directly involved in research on cohabitation reviewed what was known about the subject up to that date and discussed what needed to be done in the future to understand the phenomenon more completely and to evaluate its influence on the institutions of marriage and family. The prime recommendation for policy and position statements made by the group at the close of the Groves Conference was that consideration be given to rethinking existing laws prohibiting cohabitation, since, in the opinion of the group, the decision to cohabit should be an individual one and persons should have freedom of choice in the matter. In addition, persons who cohabit may encounter problems in regard to housing, insurance, employment, property settlement, financial proceedings (wills, trusts, Social Security payments, loans), restrictions imposed by military regulations, and establishment of paternity of offspring. All of these areas will be discussed in an effort to ascertain the cohabitor's legal position.
Personality Traits and Personal History Variables Correlated with Decisions to Have Children or to be Childfree
(1980) Gottlieb, Catherine Wilson; Hood College Psychology; Human Sciences
The purpose of this study was to assess the relationship between personal history variables, personality variables as measured by the Edwards Personal Preference Schedule, and a person's decision either to have children or to voluntarily remain childfree. The personality variables being considered were Murray's manifest needs associated with achievement, deference, order, exhibition, autonomy, affiliation, intraception, succorance, dominance, abasement, heterosexuality and aggression. Participants were selected by their response to a preliminary letter distributed to all Hood College graduate students; they and their spouses, if any, were invited to participate in the study and were asked to indicate whether or not they desire having children. The sample was heterogeneous in age, sex and personal background. Participants were asked to complete a background data sheet and the Edwards Personal Preference Schedule. Results obtained using the background questionnaire showed several significant differences: childfree persons more often had friends who were also childfree; the mothers of childfree persons more often had higher levels of education; and childfree persons more often live in urban settings. Results obtained using the Edwards Personal Preference Schedule indicate significantly higher scores for the group with children on the heterosexuality scale. The childfree group had higher scores approaching significance on the scales of abasement and endurance.
THE ISOLATION AND TRANSMISSION OF Helicobacter hepaticus sp. nov., ISOLATED FROM THE LIVERS AND INTESTINAL CONTENTS OF MICE
(1994-07) Gorelick, Peter L.; Hood College Biology; Biomedical and Environmental Science
In the fall of 1992 at the National Cancer Institute - Frederick Cancer Research and Development Center (NCI-FCRDC), A/JCr stock mice which showed suppurative skin lesions and treated and untreated A/JCr mice from a long-term toxicologic study were found to have a unique chronic active hepatitis of unknown etiology. No biological agent was known to cause such lesions. A major effort was undertaken to determine the cause of the hepatitis, since all these mice were obtained from the NCI-FCRDC Animal Production Area (NCI-FCRDC-APA). The initial approach was to examine potential environmental toxins. Upon failure to identify any specific environmental cause, a search for a possible biological agent was pursued. In the course of utilizing a Steiner's modification of the Warthin-Starry stain (Steiner's stain), pathologists found what appeared to be a helical organism in the hepatic parenchyma of affected mice. The hepatitis was successfully reproduced in A/J mice obtained from Jackson Laboratories (Jax), Bar Harbor, ME, which had been injected with liver suspensions from affected A/JCr mice. A histopathologic survey employing the Steiner's stain on livers from adult NCI-FCRDC-APA mice demonstrated hepatic lesions in numerous mouse strains (A/JCr, C3H/HeNCr, SJL/NCr, BALB/cAnNCr and SCID/NCr), while hepatic lesions were absent in others (C57BL/6NCr, B6C3F1 and nude [nu/nu]). Hepatic lesions were found more frequently in male mice than female mice. Isolation of the organism was accomplished by culturing the livers of affected A/JCr and SCID/NCr mice and incubating the suspensions on trypticase soy agar plates with 5% sheep blood and brucella blood agar with antibiotics at 37°C under microaerophilic conditions. The organism was motile, catalase positive, oxidase positive and rapidly hydrolyzed urea. The organism was tentatively designated Helicobacter hepaticus sp. nov. Subsequently, Helicobacter hepaticus sp. nov. has been cultured from the intestinal tract and feces of affected mice from the NCI-FCRDC-APA and research holding colonies. To demonstrate infectivity, the organism was injected into unaffected A/J mice from Jax. At several time points livers were aseptically collected, cultured, and a portion submitted for histopathological examination. The hepatitis and presence of the organism was confirmed by histopathology and culture. In a third transmission study, CB.17 SCID mice from Taconic Farms (Tac), Germantown, N.Y., were exposed by direct animal or fecal contact to affected SCID/NCr mice from NCI-FCRDC-APA. Over time the organism and the hepatitis were found to have been transmitted to the CB.17 SCID mice, thus demonstrating that the route of infection was fecal-oral. To date, there are no other organisms known to cause the same type of hepatitis as Helicobacter hepaticus sp. nov.. This novel organism has the potential to provide a much needed animal model for biocarcinogenesis and other human health problems.
PURIFICATION AND CHARACTERIZATION OF RECOMBINANT TOBACCO ETCH VIRUS PROTEASE
(1996-05) Goldstein, Adam Stuart; Hood College Biology; Biomedical and Environmental Science
The development of expression systems which permit the overproduction of large amounts of protein is a very important advancement in modern biotechnology. Recent developments in cloning have eased some of the traditional problems of obtaining high yields of pure product. New techniques enable the researcher to express and purify proteins of interest by fusing the expressed protein to a variety of commercially available affinity tags such as, f3-galactosidase, glutathione-S-transferase (GST) (Smith, D. 1988), and polyhistidine peptides (Guan, C. 1987). A new site specific protease, Tobacco Etch Virus protease (rTEV), has been cloned and overexpressed for the use in rapid cloning and purification procedures. In a purification scheme, the protein of interest will contain a TEV cleavage site flanked with six histidines. When the protein is cleaved only a single glycine residue at the amino terminus of the protein remains from the inserted rTEV site. With only one glycine residue left on the purified protein there is less of a chance for incorrect foldings, or for unexpected activities.

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