UNT Libraries - Browse


An 8-Step Program: Shaping and Fixed-Time Food Delivery Effects on Several Approximations and Undesired Responses in Goats.

Description: This study investigated the effects of a shaping program for halter training across 8 steps in the program and 4 trial-terminating, or "undesirable," responses. Three La Mancha goats (Capra hircus) located at the Frank Buck Zoo in Gainesville, Texas were used for the study. A fixed-time 15 s (FT-15 s) was used during the baseline conditions, to examine the effects of response contingent and response-independent food deliveries, as well as to examine what preliminary steps might not necessarily have to be shaped. All 3 goats successfully learned to allow the halter to be placed on them and to lead on the halter, although 2 of the 3 goats required an additional task analysis for the fifth step to further break down that approximation. Several of the early steps selected by the researchers were not necessary to complete the program, as determined by the baseline condition.
Date: May 2003
Creator: Fernandez, Eduardo J.

24, Lost, and Six Feet Under: Post-traumatic television in the post-9/11 era.

Description: This study sought to determine if and how television texts produced since September 11, 2001, reflect and address cultural concerns by analyzing patterns in their theme and narrative style. Three American television serials were examined as case studies. Each text addressed a common cluster of contemporary issues such as trauma, death, and loss.
Date: May 2008
Creator: Anderson, Tonya

The 1986 National Endowment for the Arts Commission: An Introspective Analysis of Two Marimba Works

Description: The marimba is rapidly achieving greater importance as a solo percussion instrument. Solo compositions for the marimba have been commissioned and performed only in the last sixty years. The 1986 National Endowment for the Arts Solo Marimba Commission is considered one of the most important commissioning projects in the history of marimba literature. Two compositions created through this project, Velocities by Joseph Schwantner and Reflections on the Nature of Water by Jacob Druckman have become two of the most influential works in contemporary marimba music. This thesis will focus on a historical perspective of the project, as well as theoretical aspects and performance issues related to these two compositions. The National Endowment for the Arts (NEA) issued a consortium commissioning grant through the Percussive Arts Society (PAS) in 1986 to three internationally renowned marimbists, William Moersch, Leigh Howard Stevens and Gordon Stout. Three Pulitzer Prize winners were brought together to compose three new works for the marimba. The resulting pieces were: Reflections on the Nature of Water by Jacob Druckman, Velocities by Joseph Schwantner, and Islands from Archipelago: Autumn Island by Roger Reynolds. A brief history of the classical concert marimba and the development of solo marimba literature is provided in the second chapter. The fourth and fifth chapters provide individual information about the pieces, including concise biographical information about the composers and an analysis of the two compositions.
Date: August 2005
Creator: Fang, I-Jen

Ability Estimation Under Different Item Parameterization and Scoring Models

Description: A Monte Carlo simulation study investigated the effect of scoring format, item parameterization, threshold configuration, and prior ability distribution on the accuracy of ability estimation given various IRT models. Item response data on 30 items from 1,000 examinees was simulated using known item parameters and ability estimates. The item response data sets were submitted to seven dichotomous or polytomous IRT models with different item parameterization to estimate examinee ability. The accuracy of the ability estimation for a given IRT model was assessed by the recovery rate and the root mean square errors. The results indicated that polytomous models produced more accurate ability estimates than the dichotomous models, under all combinations of research conditions, as indicated by higher recovery rates and lower root mean square errors. For the item parameterization models, the one-parameter model out-performed the two-parameter and three-parameter models under all research conditions. Among the polytomous models, the partial credit model had more accurate ability estimation than the other three polytomous models. The nominal categories model performed better than the general partial credit model and the multiple-choice model with the multiple-choice model the least accurate. The results further indicated that certain prior ability distributions had an effect on the accuracy of ability estimation; however, no clear order of accuracy among the four prior distribution groups was identified due to an interaction between prior ability distribution and threshold configuration. The recovery rate was lower when the test items had categories with unequal threshold distances, were close at one end of the ability/difficulty continuum, and were administered to a sample of examinees whose population ability distribution was skewed to the same end of the ability continuum.
Date: May 2002
Creator: Si, Ching-Fung B.

Academic Dishonesty: Attitudes and Behaviors of Fundamentalist Christian College Students

Description: This study was designed to examine: (1) the extent to which cheating occurs in fundamentalist Christian colleges; (2) the attitudes of fundamentalist Christian college students toward cheating; (3) attitudes of fundamentalist Christian college students toward cheating among their peers; (4) the kinds of cheating practices of fundamentalist Christian college students; (5) the degree to which students engage in neutralizing behavior to justify cheating; (6) differences in cheating behaviors according to gender; (7) differences in cheating behaviors according to ethnicity; and (8) differences in cheating behaviors according to the length of duration of Christian commitment. Based upon the responses of 337 students attending 3 different Christian colleges, it was concluded that: (1) most Christian fundamentalist students do not engage in cheating; (2) respondents believe that each of 17 self-reported cheating behaviors are serious forms of cheating; (3) respondents are unlikely to report cheating among peers; (4) plagiarism is the most common cheating behavior; (5) most respondents justify cheating on the basis of the workload at school and the pressure to obtain good grades; (6) there are no differences in cheating behavior according to gender; (7) there are differences in cheating behavior according to groups; and (8) most respondents do not cheat regardless of the self-reported duration of Christian commitment.
Access: This item is restricted to UNT Community Members. Login required if off-campus.
Date: December 2000
Creator: Sunday, William G.

Academic excellence and instructional expenditures in Texas.

Description: Public school per pupil costs and demands for better performance have increased over the past several decades. While the overall per pupil expenditures have increased, the percent of the educational dollar directed toward instructional activities has remained at approximately 60%. A grass-roots movement known as the "65% Solution" caught national attention by claiming that schools are not efficiently allocating resources into areas that have the greatest link to student achievement, such as instruction. Proponents of the 65% Solution claim that per pupil expenditures can be increased by shifting funds from areas considered non-instructional to areas that directly impact student instruction, such as teachers and instructional materials. The purpose of this study was to determine the relationship between district Panel Recommended and Commended Performance TAKS Reading/ELA and Math results and three measurements of instructional expenditures, Instructional Staff Percent; TEA Instructional Expenditure Ratio; and the NCES Instructional Expenditure Ratio (65% Solution), in Texas public schools. Data was collected from the 2003-2004 AEIS report. Multiple regression was used to conduct the analyses. In most instances, there was little, if any, relationship between TAKS Reading/ELA and TAKS Math, and the Instructional Staff Percent (ISP), TEA Instructional Expenditure Ratio (TIER), and NCES Instructional Expenditure Ratio (NIER). However, a low to moderate relationship was discovered in the comparison of TAKS Reading/ELA, and the ISP and TIER. This result was the same for both the Panel Recommended and Commended Performance. In every instance, the ISP and TIER showed positive, statistically significant, relationships to TAKS results. The NIER, or 65% Solution, had the lowest correlation and was statistically insignificant in three out of four analyses.
Date: August 2006
Creator: Helvey, Jearl Kenton

Accent and Grouping Structures in the String Quartets of Béla Bartók

Description: The music of Béla Bartók is defined in part by its unique blend of rhythmic vitality and inventiveness, and his string quartets offer a glimpse into a consistency of technique evident throughout his compositional career. Bartók's rhythmic environments are primarily metrical, but many of his rhythmic configurations are placed in such a way as to potentially override established meter. It is necessary, therefore, to institute an analytical means by which the delineation and comparison of rhythmic structures both within and without the metrical context may be accomplished. An analytical method using Timepoint Accent Structures (TAS) allows for the comparison of rhythms resulting from patterns of accent produced by pitch onset, dynamic stress, articulation or any other accentual factors. Timepoint Grouping Structures (TGS) delineate the number of timepoints present in alternating groups/blocks in a texture, thereby allowing for the recognition of patterning created by these larger groups. By applying TAS and TGS analysis, relationships of rhythmic equivalency, rotation, retrograde, complementation, augmentation, diminution, subset, superset, exchange, compression and expansion are clearly confirmed in the string quartets. In addition, symmetrical structures and arithmetic progressions are discovered. In many ways, Bartók's rhythmic organization mimics his procedures of pitch structuring.
Date: May 2001
Creator: Bocanegra, Cheryl D.

Acceptance and use of corporal punishment among parents of biologic and non-biologic children.

Description: Objective: Differences between biologic and non-biologic parents' acceptance and use of ordinary corporal punishment and use of explaining/reasoning as a disciplinary tool are examined from a sociobiological theoretical perspective. Method: Cross tabulations are used on data from a national survey conducted by the Gallup Organization in 1995. Results: Contrary to predictions, differences between biologic and non-biologic parents' acceptance of ordinary corporal punishment and the use of explaining/reasoning are not statistically significant. In addition, biologic parents are found to use ordinary corporal punishment significantly more often than non-biologic parents. Conclusions: The sociobiological theoretical perspective likely underestimates the influence of culture and social structure on parent-child interactions.
Date: May 2006
Creator: Hall, Ellie Tiedeman

Accessibility and Authenticity in Julia Smith's Cynthia Parker

Description: In 1939, composer Julia Smith's first opera Cynthia Parker dramatized the story of a Texas legend. Smith manipulated music, text, and visual images to make the opera accessible for the audience in accordance with compositional and institutional practices in American opera of the 1930s. Transparent musical themes and common Native Americans stereotypes are used to define characters. Folk music is presented as diegetic, creating a sense of authenticity that places the audience into the opera's Western setting. The opera is codified for the audience using popular idioms, resulting in initial but not lasting success.
Date: December 2007
Creator: Buehner, Katie R.

Accessing Information on the World Wide Web: Predicting Usage Based on Involvement

Description: Advice for Web designers often includes an admonition to use short, scannable, bullet-pointed text, reflecting the common belief that browsing the Web most often involves scanning rather than reading. Literature from several disciplines focuses on the myriad combinations of factors related to online reading but studies of the users' interests and motivations appear to offer a more promising avenue for understanding how users utilize information on Web pages. This study utilized the modified Personal Involvement Inventory (PII), a ten-item instrument used primarily in the marketing and advertising fields, to measure interest and motivation toward a topic presented on the Web. Two sites were constructed from Reader's Digest Association, Inc. online articles and a program written to track students' use of the site. Behavior was measured by the initial choice of short versus longer versions of the main page, the number of pages visited and the amount of time spent on the site. Data were gathered from students at a small, private university in the southwest part of the United States to answer six hypotheses which posited that subjects with higher involvement in a topic presented on the Web and a more positive attitude toward the Web would tend to select the longer text version, visit more pages, and spend more time on the site. While attitude toward the Web did not correlate significantly with any of the behavioral factors, the level of involvement was associated with the use of the sites in two of three hypotheses, but only partially in the manner hypothesized. Increased involvement with a Web topic did correlate with the choice of a longer, more detailed initial Web page, but was inversely related to the number of pages viewed so that the higher the involvement, the fewer pages visited. An additional indicator of usage, the average amount ...
Date: May 2003
Creator: Langford, James David

Accident versus Essence: Investigating the Relationship Among Information Systems Development and Requirements Capabilities and Perceptions of Enterprise Architecture

Description: Information systems (IS) are indelibly linked to the global economy and are indispensable to society and organizations. Despite the decisive function of IS in organizations today, IS development problems continue to plague organizations. The failure to get the system requirements right is considered to be one of the primary, if not the most significant, reasons for this high IS failure rate. Getting requirements right is most notably identified with Frederick Brooks' contention that requirements are the essence of what IT professionals do, all the rest being accidents or risk management. However, enterprise architecture (EA) may also provide the discipline to bridge the gap between effective requirements, organizational objectives, and the actual IS implementations. The intent of this research is to examine the relationship between IS development capabilities and requirements analysis and design capabilities within the context of enterprise architecture. To accomplish this, a survey of IT professionals within the Society for Information Management (SIM) was conducted. Results indicate support for the hypothesized relationship between IS development and requirements capabilities. The hypothesized relationships with the organizational demographics were not supported nor was the hypothesized positive relationship between requirements capabilities and EA perceptions. However, the nature of the relationship of requirements and EA provided important insight into the relationship leading to several explanations as to its meaning and contributions to research and practice. This research contributes to IS development knowledge by providing evidence of the essential role of requirements in IS development capabilities and in IS development maturity. Furthermore, contributions to the nascent field of EA research and practice include key insight into EA maturity, EA implementation success, and the role of IT professionals in EA teams. Moreover, these results provide a template and research plan of action to pursue further EA research in exploring EA maturity models and critical success factors, ...
Date: August 2009
Creator: Salmans, Brian R.

"According to Their Wills and Pleasures": The Sexual Stereotyping of Mormon Men in American Film and Television

Description: This thesis examines the representation of Mormon men in American film and television, with particular regard for sexual identity and the cultural association of Mormonism with sexuality. The history of Mormonism's unique marital practices and doctrinal approaches to gender and sexuality have developed three common stereotypes for Mormon male characters: the purposeful heterosexual, the monstrous polygamist, and the self-destructive homosexual. Depending upon the sexual stereotype in the narrative, the Mormon Church can function as a proponent for nineteenth-century views of sexuality, a symbol for society's repressed sexuality, or a metaphor for the oppressive effects of performing gender and sexuality according to ideological constraints. These ideas are presented in Mormon films such as Saturday's Warrior (1989) as well as mainstream films such as A Mormon Maid (1917) and Advise and Consent (1962).
Date: May 2009
Creator: Sutton, Travis

Accounting for Human Resources: Implications for Theory and Practice.

Description: Knowledge workers are an important resource for the typical modern business firm, yet financial reporting ignores such resources. Some researchers contend that the accounting profession has stressed reliability in order to make the accounting appear objective. Others concur, noting that accounting is an insecure profession and adopts strict rules when faced with uncertainty. Accountants have promulgated a strict rule to expense human resource costs, although many know that such resources have future benefits. Some researchers suggest that any discipline must modify its language in order to initiate change toward providing useful social ameliorations. If accounting theorists extend this idea to the accounting lexicon.s description of investments in human resources, investors and other accounting user groups might gain greater insight into how a firm fosters and nourishes human capital. I tested three hypotheses related to this issue by administering an experiment designed to assess financial analysts. perceptions about alternative financial statement treatments of human resources in an investment recommendation task. I predicted that (1) analysts' perceptions of the reliability (relevance) of the information they received would decrease (increase) as the treatment of human resources increasingly violated GAAP (became more current-oriented), (2) analysts exposed to alternative accounting treatments would report a lower likelihood of recommending that their clients invest in the company in the task, and (3) financial analysts who ranked reliability (relevance) as a more important information quality would be less (more) likely to recommend that their clients buy the stock represented in the case because the treatment of human resources on the financial statements violated GAAP (was more current-oriented) as compared to analysts who ranked reliability (relevance) as being lower (higher) in importance. Analysts receiving financial statements with accounting treatments of human resource costs that violated GAAP judged such information as less reliable and were also less likely to recommend ...
Date: December 2001
Creator: Stovall, Olin Scott

Acculturation and Sociocultural Influences as Predictors of Family Relationships and Body Image Dissatisfaction in African American, Hispanic American, and European American Women

Description: Ethnic differences in etiological factors linked to body image dissatisfaction and eating disorders were examined. In addition, the interaction of acculturation and body image dissatisfaction in influencing minority women's relationships with their parents was investigated. Participants consisted of 302 undergraduates from three ethnic groups: Caucasian, Hispanic American, and African American women who were administered self-report measures. Differences were not found between the groups in body image dissatisfaction. Low self-esteem, internalization of the thin ideal, and family emphasis on weight and appearance were all related to more body image dissatisfaction for each of these groups; however, differences in degree of endorsement were also noted between the ethnic groups on these factors. Based on the interaction findings (body image x acculturation) separation from one's mother was found in the area of attitudes and emotions for the Hispanic sample but not for the African American sample on any of the parent scales. Areas for future research and implications for diagnosis and treatment of minority populations are also discussed.
Date: December 2006
Creator: Garcia-Rea, Elizabeth Ann

Acculturation Level, Generational Status and Gender: Their Role in Acculturative Stress in Young Adolescent Mexican Americans

Description: The purpose of this study was to determine relationships between acculturation level, generational status, and gender with acculturative stress. Acculturation level was determined by the Acculturation Rating Scale for Mexican Americans-II (ARSMA-II) and acculturative stress was determined by the Societal, Attitudinal, Familial and Environmental Acculturative Stress Scale-Children's Version (SAFE-C). Subjects included 1268 Hispanic children ages 11-15. In order to validate the usefulness of the ARSMA-II with this sample, analyses were conducted between acculturation level and generational status. The Pearson product moment correlation (r=.44) and the ANOVA between the mean acculturation score and generational status were significant. However, the mean acculturation score from this study was considerably lower than the ARSMA-II score; therefore, new acculturation levels were developed to establish local adolescent norms for the ARSMA-II. All analyses involving acculturation levels were conducted using both the ARSMA-II and new acculturation levels because 300 subjects were reclassified with the new norms. Significant results were similar using both acculturation levels; however, there were more between group differences using the new acculturation levels. It was hypothesized that as acculturation level increased toward the Anglo culture, acculturative stress would decrease. The one-way ANOVA confirmed this relationship. It was also hypothesized that as generational status increased, acculturative stress would decrease. A one-way ANOVA also supported this hypothesis. In order to replicate previous findings on gender, a one-way ANOVA was conducted with acculturative stress and acculturation level. Results for both were non-significant. Overall findings indicate that generational status and acculturation level have a significant impact on acculturative stress in Hispanic children; however, gender does not seem to be a factor. Findings emphasize the importance of addressing cultural issues in the assessment, intervention, and treatment of acculturating Hispanic children. Furthermore, the ARSMA-II appears to be a useful instrument in assessing acculturation level in young adolescent Hispanics though new ...
Date: August 2004
Creator: Manning, Suzanne C.

Acculturation, Parental Control, and Adjustment among Asian Indian Women

Description: The present study examines the relationship between acculturation, parental control, and psychological adjustment among adult first and second-generation Asian Indian women who have immigrated, or whose parents have immigrated to the United States, from the Indian state of Kerala. Data from 73 participants indicate second-generation immigrants report poorer psychological adjustment than do their counterparts. Additionally, regression analyses reveal discomfort towards Kerala culture significantly predicts depressive symptoms, while high maternal control predicts self-esteem. Qualitative data were collected to provide richer understanding of immigrants' adaptation to the U.S. Implications of this research may impact mental health practitioners' ability to improve quality of life with Asian Indian women from Kerala.
Date: May 2007
Creator: Varghese, Anitha

Acculturative Processes and Their Impact on Self-Reports of Psychological Distress in Mexican-American Adolescents

Description: The current study examined the effects of acculturative processes on the self-report of behavioral problems in Hispanic children ages 11-14. Acculturation was measured by the Acculturation Rating Scale for Mexican Americans-II (ARSMA-II) (ã Sage Publications, Thousand Oaks, CA, www.sagepub.com) (Cuellar, Arnold, and Maldonado, 1995) and the self-report of behavioral symptoms was assessed using the Youth Self-Report (ã T.M. Achenbach, Burlington, VT, www.aseba.com) (Achenbach, 1991). It was hypothesized that while both the linear and orthogonal categories of acculturation would account for a significant proportion of the variance in behavior problems in this age group, the orthogonal model would account for a larger proportion of variance due to its multidimensional nature. As well, it was hypothesized that the experimental Marginalization scales of the ARSMA-II would be predictive of behavioral problems. Multivariate analysis of variance was used to test these hypotheses and results were non-significant for the linear, orthogonal, and marginalization categories. The effects of the ethnic/cultural homogeneity of the region from which the sample was drawn, the buffering of social support, and the developmental aspects of ethnic identity are discussed as factors which may have influenced the potential impact of acculturative stress on psychological and behavioral functioning.
Date: May 2003
Creator: Garrison, Lance A.

Accuracy of Self-Reported Height, Weight, and Calculated BMI and Resulting FITNESSGRAM® Healthy Fitness Zone Classification

Description: The determination of adiposity in adolescents is often assessed with calculations of body mass indices (BMI). Researchers often obtain these measurements from self-reported (SR) values. The purpose of this study was to determine the accuracy of SR height, weight, and calculated BMI (from height and weight). SR and actual measured (ME) BMI values were compared with standards from the FITNESSGRAM® Healthy Fitness Zone (HFZ) classifications. SR height and calculated BMI were found to be accurate while SR weight was, on average, underreported by 4.77 lbs. Because of these errors in SR height and weight, accuracy of classification into the FITNESSGRAM® HFZ was compromised. Consequently, it is important that researchers ascertain actual values of height and weight when measuring adolescents rather than use those from self-reports.
Access: This item is restricted to UNT Community Members. Login required if off-campus.
Date: May 2006
Creator: Rowell, Chelsie Joyce

Accuracy Variations in Human Facial Identification Based on Time of Exposure.

Description: This study examined the relationship between time of exposure to the human face and accurate subsequent photo line-up identification. A volunteer group of 124 undergraduate students was divided into three approximately equal sized subgroups. The three groups were then exposed to a video or a portion of a video depicting a theft. Exposure times ranged from two minutes to 30 seconds. The subjects were then given a questionnaire and shown a photo line-up of the mock perpetrator and five foils. Subjects were asked to identify the perpetrator and mark that identification on the questionnaire. Results of the experiment indicated that the longer a subject was exposed the greater the possibility of an accurate identification.
Access: This item is restricted to UNT Community Members. Login required if off-campus.
Date: December 2006
Creator: Cowle, Kenneth M.

Acting Ethically: Behavior and the Sustainable Society

Description: One of the most important factors for creating the sustainable society is that the individuals in that society behave in an environmentally sustainable fashion. Yet achieving appropriate behavior in any society is difficult, and the challenge is no less with regards to sustainability. Three of the most important factors for determining behavior have recently been highlighted by psychologists: personal efficacy, social influence, and internal standards. Because these three factors play a prominent role in behavior, it is necessary to examine what role they play in creating sustainability and how they may be utilized to achieve optimal behavior patterns. Ultimately, in order to achieve sustainability solutions must focus on individual action, realistic governmental regulation, and sustained, direct encounters with the natural world. While much time and energy has been spent on social influence and personal efficacy, less has been devoted to internal standards and this area needs more attention if there is to be any realistic attempt at creating proper behavior patterns.
Date: August 2007
Creator: Sewell, Patrick

The Actions and Operational Thinking of Generals Stratemeyer and Partridge during the Korean War: Adjusting to Political Restrictions of Air Campaigns

Description: Airpower played an important supporting role in the Korean War, and as General of the Army Douglas MacArthur pursued victory in the war and President Harry S Truman's objectives altered throughout the first year of the conflict, tension arose between the two men. One issue in these frictions was the restriction of airpower. Not only MacArthur, but also his admiring subordinate Lieutenant General George E. Stratemeyer commanding the Far East Air Forces, and Fifth Air Force commander Major General Earle E. Partridge opposed the restrictions which had been imposed on airmen from the outset of the conflict. Stratemeyer did so partly because of his loyalty to MacArthur, who wanted latitude in coping with the situation in the field and defeating the Communist enemy. Partridge did so because he thought they endangered his personnel and limited the effectiveness of airpower in the war. These commanders had a fundamentally different opinion from Washington regarding the likelihood of overt Soviet intervention in the war, and because they did not think the Korean War would become a world war, they were more willing than Washington to prosecute the war more aggressively. MacArthur's conflict ended with his removal in April 1951, and Stratemeyer (who suffered a heart attack weeks afterward) continued to advocate for forceful American foreign policy in Asia during his retirement. Partridge eventually earned four stars and long after the war likewise continued to disfavor the restrictions which had been put in place. Between oral history interviews in 1974 and 1978, however, Partridge reconsidered the issue of restrictions. He expressed that the Korean War had been a considerable challenge without a wider war, implying that restrictions had perhaps been important.
Date: May 2008
Creator: Sambaluk, Nicholas Michael

An Actor-Partner Interdependence Model of Attachment Processes, Conflict Resolution, and Psychological Abuse on Relationship Quality in a Community Sample of Heterosexual Couples.

Description: The purpose of this study is to determine whether adult attachment style, psychological abuse in the marriage, conflict resolution strategies, and gender are associated with relational quality in childless couples in the early years of their marriage. Data were collected from 92 married couples who were recruited from university campuses, churches, and community organizations through e-mails, flyers, newspaper advertisements and mailings. Conceptualizing the interdependence of dyadic data from the actor-partner interdependence model (APIM), multilevel linear modeling (MLM) was used to analyze differences within and between couples. It was hypothesized that higher levels of attachment anxiety or avoidance, psychological abuse, and maladaptive conflict resolution strategies would be associated with lower relational quality. Results indicated that attachment avoidance had stronger associations with relational quality than did attachment anxiety, and that higher levels of attachment avoidance were associated with lower relational quality. Additionally, findings indicated a direct negative relationship between both actor and partner psychological abuse and the actor's relational quality. The discussion section addresses strengths and limitations of the present study as well as directions for future research.
Date: May 2009
Creator: Bretz, Karen

N-Acylethanolamine Metabolism During Seed Germination: Molecular Identification of a Functional N-Acylethanolamine Amidohydrolase

Description: N-Acylethanolamines (NAEs) are endogenous lipid metabolites that occur in a variety of dry seeds, and their levels decline rapidly during the first few hours of imbibition (Chapman et al., 1999, Plant Physiol., 120:1157-1164). Biochemical studies supported the existence of an NAE amidohydrolase activity in seeds and seedlings, and efforts were directed toward identification of DNA sequences encoding this enzyme. Mammalian tissues metabolize NAEs via an amidase enzyme designated fatty acid amide hydrolase (FAAH). Based on the characteristic amidase signature sequence in mammalian FAAH, a candidate Arabidopsis cDNA was identified and isolated by reverse transcriptase-PCR. The Arabidopsis cDNA was expressed in E. coli and the recombinant protein indeed hydrolyzed a range of NAEs to free fatty acids and ethanolamine. Kinetic parameters for the recombinant protein were consistent with those properties of the rat FAAH, supporting identification of this Arabidopsis cDNA as a FAAH homologue. Two T-DNA insertional mutant lines with disruptions in the Arabidopsis NAE amidohydrolase gene (At5g64440) were identified. The homozygous mutant seedlings were more sensitive than the wild type to exogenously applied NAE 12:0. Transgenic seedlings overexpressing the NAE amidohydrolase enzyme showed noticeably greater tolerance to NAE 12:0 than wild type seedlings. These results together provide evidence in vitro and in vivo for the molecular identification of Arabidopsis NAE amidohydrolase. Moreover, the plants with altered NAE amidohydrolase expression may provide new tools for improved understanding of the role of NAEs in germination and seedling growth.
Date: August 2004
Creator: Shrestha, Rhidaya

N-Acylethanolamine (NAE) Profiles Change During Arabidopsis Thaliana Seed Germination and Seedling Growth

Description: An understanding of the potential roles as lipid mediators of a family of bioactive metabolites called N-acylethanolamines (NAEs) depends on their accurate identification and quantification. The levels of 18C unsaturated NAEs (e.g. NAE18:2, NAE 18:3, etc.) in wild-type seeds (about 2000 ng/g fw) generally decreased by about 80% during germination and post-germinative growth. In addition, results suggest NAE-degradative fatty acid amide hydrolase (FAAH) expression does not play a major role in normal NAE metabolism as previously thought. Seedlings germinated and grown in the presence of abscisic acid (ABA), an endogenous plant hormone, exhibited growth arrest and secondary dormancy, similar to the treatment of seedlings with exogenous N­lauroylethanolamine (NAE12:0). ABA-mediated growth arrest was associated with higher levels of unsaturated NAEs. Overall, these results are consistent with the concept that NAE metabolism is activated during seed germination and suggest that the reduction in unsaturated NAE levels is under strict temporal control and may be a requirement for normal seed germination and post-germinative growth.
Date: August 2006
Creator: Wiant, William C.