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Retrospective Theses and Dissertations

1993

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Articles 1 - 30 of 155

Full-Text Articles in Life Sciences

The Political Economy Of International Agricultural Protection , Virender Gautam Jan 1993

The Political Economy Of International Agricultural Protection , Virender Gautam

Retrospective Theses and Dissertations

The purpose of this study has been to investigate some prominent determinants of agricultural protection across industrialized and developing countries. The hypotheses tested are that consumers' food security concerns and producers' pressure group characteristics play an eminent role in the determination of political market equilibrium in the agricultural sector. The methodology employed provides an integrated development of theoretical and empirical analysis;The comparative static results of the theoretical models are tested using the ordinary least squares, generalized least squares, pooled cross-section time-series, and Probit and Logit estimation techniques. The analysis includes data from 30 industrialized and developing countries for the ...


An Evaluation Of The Role Of Regional Centers For Research, Teaching And Extension In The Educational Function Of The Colegio De Postgraduados, Mexico , Anibal Quispe Limaylla Jan 1993

An Evaluation Of The Role Of Regional Centers For Research, Teaching And Extension In The Educational Function Of The Colegio De Postgraduados, Mexico , Anibal Quispe Limaylla

Retrospective Theses and Dissertations

The purpose of this study was to assess the impact of the regional centers for research, teaching, and extension on the educational function of the Colegio de Postgraduados. Specifically, the objectives were to: (1) Assess the participation of campus faculty and students in the regional centers, (2) Assess the impact of faculty members' academic activities in regional centers upon their professional competencies and academic performance, (3) Assess the participation of regional center faculty in academic activities on campus, (4) Assess the factors affecting participation of campus faculty in regional centers and regional center faculty on campus, (5) Determine perceptions of ...


Essays In Dynamic Adjustment, Structural Change And Data Analysis: Applications To The Demand For Meat In The Us , Jacinto Fama Fabiosa Jan 1993

Essays In Dynamic Adjustment, Structural Change And Data Analysis: Applications To The Demand For Meat In The Us , Jacinto Fama Fabiosa

Retrospective Theses and Dissertations

A number of reasons are cited in the literature to explain the over rejection of theoretical demand properties in empirical studies. This dissertation examines two of the most common explanations; the Dynamic Adjustment Hypothesis (DAH) and the Structural Change Hypothesis (SCH), as it is applied to meat demand in the U.S. That is, failure to account for dynamics and variation of parameters over time may be the root cause of the over rejection. Despite the inclusion of dynamics and parameter variation in the model, however, the theoretical demand properties still can not be accepted;The first paper clearly shows ...


Development And Application Of Procedures To Detect Low Molecular Mass Enzymes And Evaluation Of A Zymogram Method For Microbial Endoglucanases , Scott Michael Holt Jan 1993

Development And Application Of Procedures To Detect Low Molecular Mass Enzymes And Evaluation Of A Zymogram Method For Microbial Endoglucanases , Scott Michael Holt

Retrospective Theses and Dissertations

A procedure was developed for the detection of low molecular mass (<10 kDa) enzymes from microorganisms, commercial enzyme preparations, and mammalian liver tissue samples. Samples were subjected to ultrafiltration with a 10-kDa exclusion membrane and enzyme activities were detected from ultrafiltrates by radial gel diffusion in substrate-laden agar media. Of 257 samples examined, ultrafiltrates from 14 fungal isolates, including Aspergillus niger ATCC 9029, were positive for CMCase and xylanase activities. A purified endoglucanase from Bacillus subtilis PAP 115, with a molecular mass of 30-33 kDa, was also ultrafiltrate-positive for CMCase activity. Denaturing zymogram analyses of the ultrafiltrates from A. niger and B. subtilis revealed that the molecular masses of the enzymes were 23 and 30 kDa, respectively. The ability of the enzymes to pass through the ultrafilters could be attributed to discrepancies in the membrane pore sizes or, more likely, to an elongated, tapered, or compact molecular shape;A denaturing zymogram method was evaluated for its ability to detect endoglucanase components from Trichoderma reesei, Myrothecium verrucaria, and Bacillus subtilis. Enzyme samples from each microorganism were denatured at 95°C for 5 minutes in the presence of 3% SDS and were subjected to SDS-polyacrylamide gel electrophoresis. Carboxymethylcellulose was incorporated into the separating gel. After electrophoresis, the gels were washed with water for 1 hour to allow for enzyme renaturation. Endoglucanase activity bands were detected by staining the gels with 0.1% congo red. In general, molecular mass values of endoglucanases identified by zymogram analyses were consistent with molecular mass values of endoglucanases from T. reesei, M. verrucaria, and B. subtilis.


Genetic And Physical Analysis Of The Staphylococcus Aureus Chromosome Using Two Tn917 Derivatives , Laura Lea Hruska Jan 1993

Genetic And Physical Analysis Of The Staphylococcus Aureus Chromosome Using Two Tn917 Derivatives , Laura Lea Hruska

Retrospective Theses and Dissertations

Tandem chromosomal duplications offer a means of genetic and physical mapping in microorganisms which lack defined conjugal systems. To determine if tandem chromosomal duplications occur in S. aureus, two libraries of transposon-induced auxotrophic mutations with different resistance phenotypes were needed;To complement the existing library of Tn551-induced auxotrophs, two Tn917lac derivatives were constructed: Tn917G, which contains the gentamicin-resistance gene of Tn4001, and Tn917T, which contains the tetracycline-resistance gene of pT181 and sequences of the Gram-negative cloning vector p34H. Transposon mutagenesis performed with Tn917G and Tn917T demonstrated that these two constructs are useful tools in the genetic analysis of the S ...


Effects Of Usda Quality Grade And Heating On Palatability, Cholesterol Content, Fatty Acid And Proximate Composition Of Beef Strip Loin Steaks , Robert Dean Johnson Jan 1993

Effects Of Usda Quality Grade And Heating On Palatability, Cholesterol Content, Fatty Acid And Proximate Composition Of Beef Strip Loin Steaks , Robert Dean Johnson

Retrospective Theses and Dissertations

The objectives of this investigation were to determine the influence that broiler temperature and degree of doneness had upon palatability, cholesterol content (CC), and fatty acid (FA) and proximate composition (PC) of beef strip loin steaks from different USDA quality grades. Seven strip loins were obtained from each of USDA Standard, low Select, high Select, low Choice, ave to high Choice, and low to ave Prime quality carcasses of known age, ancestry and management. After storing 9 days (d) postmortem (PM), 3.0 cm steaks were cut (except Prime = 23 d), vacuum-packaged and frozen. After thawing, steaks were broiled at ...


Genetic Characterization And Molecular Cloning Of Genes Involved In Kernel Development In Zea Mays , Michael John Scanlon Jan 1993

Genetic Characterization And Molecular Cloning Of Genes Involved In Kernel Development In Zea Mays , Michael John Scanlon

Retrospective Theses and Dissertations

This dissertation describes the genetic and molecular characterization of maize genes that are required for kernel development. Maize stocks in which the Robertson's Mutator (Mu) transposable element system are especially active were used to generate 75 mutations affecting kernel development. Sixty-four kernel mutations were located to chromosome arm, and 17 were placed to more precise locations on the maize genetic map. Viability tests of kernels homozygous for defective kernel (dek) mutations revealed numerous pleiotropic effects on plants obtained from mutant kernels. Fifteen putative Mutator-induced mutations tested negative for allelism to any known gene required for kernel development, and thus ...


Risk Management Strategies And Iowa Farmers: A Logit Analysis Of The Use Of Federal Crop Insurance, Jana Pinkasova Jan 1993

Risk Management Strategies And Iowa Farmers: A Logit Analysis Of The Use Of Federal Crop Insurance, Jana Pinkasova

Retrospective Theses and Dissertations

No abstract provided.


Charged Fusions For Enhanced Protein Purification And Immobilization By Ion-Exchange , Meng Hong Heng Jan 1993

Charged Fusions For Enhanced Protein Purification And Immobilization By Ion-Exchange , Meng Hong Heng

Retrospective Theses and Dissertations

This work was undertaken to investigate the enhanced binding of genetically engineered [beta]-galactosidase fusions in ion-exchange. The fusions used had a series of polyaspartate tails of the form: Gly-Asp-Pro-Met-Ala-(Asp)[subscript] n-Tyr fused to the carboxyl termini of the wild type [beta]-galactosidase (BGWT). The resulting fusions carried additional 1, 5, 11, and 16 negative charges and are designated as BGCD1, BGCD5, BGCD11, and BGCD16, respectively;The use of charged fusions for selective protein recovery was studied using hollow fiber ion-exchange membranes. The added tails allowed selective binding and release of [beta]-galactosidase in active form from Escherichia coli ...


A Field Portable Ultrasound System For Bovine Tissue Characterization , Kyle Harold Holland Jan 1993

A Field Portable Ultrasound System For Bovine Tissue Characterization , Kyle Harold Holland

Retrospective Theses and Dissertations

Efforts by beef producers and beef packers to reduce carcass losses and to move the industry to a value-based marketing system have renewed their interest in the development of new electronic grading techniques for assessing beef carcass composition. A custom ultrasonic data acquisition system has been developed for the purpose of investigating the feasibility of beef tissue characterization. The unit developed is a compact, hand-held, six channel battery-operated data logger capable of sampling A-mode ultrasound signals at a rate of 15 megasamples per second. A custom epoxy encapsulated ultrasound transducer array was developed to fit the inner curvature of the ...


Kinetics Of The Disappearance Of Lipoprotein Cholesteryl Esters In Pigs As Affected By Dietary Fat , Terry Durk Faidley Jan 1993

Kinetics Of The Disappearance Of Lipoprotein Cholesteryl Esters In Pigs As Affected By Dietary Fat , Terry Durk Faidley

Retrospective Theses and Dissertations

Forty crossbred, castrated male pigs were fed diets containing primarily beef tallow (T) or soy oil (S) at 20% or 40% of energy as fat in a 2 x 2 factorial design. During week 6, pigs were fitted with femoral arterial, common bile duct, and duodenal catheters. After week 8, pigs were injected with autologous low-density lipoprotein (LDL) containing [superscript]3H-cholesteryl esters and high-density lipoprotein (HDL) containing [superscript]14C-cholesteryl esters. Blood and bile were collected for 48 hours. Disappearance of the labeled cholesteryl esters fit a biexponential function, and the parameters of the function were described by compartmental analysis. Pigs ...


Tailoring The Ph Dependence Of Glucoamylase From Aspergillus Awamori By Mutagenesis , Ufuk Bakir Jan 1993

Tailoring The Ph Dependence Of Glucoamylase From Aspergillus Awamori By Mutagenesis , Ufuk Bakir

Retrospective Theses and Dissertations

A program of cassette mutagenesis was undertaken in the active site of Aspergillus awamori glucoamylase, mainly to alter the effect of pH dependence of the enzyme but also to determine possible functions of the mutated residues. For this purpose, nine single amino acid mutants were prepared and expressed in Saccharomyces cerevisiae, and their effects were determined by using steady-state enzyme kinetics;Three different groups of mutations were designed. In the first group, Glu179 → Asp, Asp176 → Glu, and Glu180 → Asp mutations were prepared. The Glu179 → Asp mutation led to a very large decrease in k[subscript] cat but no change in ...


Site-Directed Mutagenesis To Enhance Thermostability Of Aspergillus Awamori Glucoamylase Expressed In Saccharomyces Cerevisiae , Hsiu-Mei Chen Jan 1993

Site-Directed Mutagenesis To Enhance Thermostability Of Aspergillus Awamori Glucoamylase Expressed In Saccharomyces Cerevisiae , Hsiu-Mei Chen

Retrospective Theses and Dissertations

A program of site-directed mutagenesis was undertaken to enhance thermostability of Aspergillus awamori glucoamylase. Nine mutations were designed, based on three different irreversible thermoinactivation mechanisms of glucoamylase. Each mutant was expressed in Saccharomyces cerevisiae, and their production, activities, and irreversible thermoinactivation rates were determined;First, the Asn182 and Asn395 residues were each replaced with Gln to reduce their deamidation rates. Asn395, but not Asn182, was N-glycosylated by yeast. Deletion of the N-glycan linked to Asn395 did not affect specific activity, but greatly decreased enzyme secretion and thermostability. Replacement of Asn182 by Gln did not change glucoamylase specific activity or thermostability ...


Gene Expression Strategies Of Barley Yellow Dwarf Virus , S. P. Dinesh-Kumar Jan 1993

Gene Expression Strategies Of Barley Yellow Dwarf Virus , S. P. Dinesh-Kumar

Retrospective Theses and Dissertations

Barley yellow dwarf virus (BYDV) has a positive sense, 5.7kb RNA genome encoding at least six open reading frames (ORFs). BYDV uses variety of unusual translational strategies to express its genes. These include frameshifting in the polymerase (60K) ORF, leaky scanning at the AUGs of the overlapping coat protein (CP) and 17K ORFs, and readthrough of the CP stop codon;Full-length cDNA clone of BYDV-PAV has been constructed to understand functions of different viral genes and the roles of specific sequences in translation, replication and encapsidation. Translation in cell-free extracts using in vitro synthesized full-length transcripts resulted in expected ...


Characterization Of The Distribution And Ontogeny Of Galanin Containing Systems During The Development Of The Brain , Joel Keith Elmquist Jan 1993

Characterization Of The Distribution And Ontogeny Of Galanin Containing Systems During The Development Of The Brain , Joel Keith Elmquist

Retrospective Theses and Dissertations

The distribution of galanin (GAL) containing systems was characterized in the brain of the adult and developing Brazilian opossum (Monodelphis domestica). Nuclear groups containing GAL-like immunoreactivity (GAL-IR) in cell bodies and fibers were seen throughout the adult and developing opossum brain. In the developing brain, GAL-IR was seen as early as 1 day postnatal (PN) in the developing hypothalamus and brainstem. Since neurogenesis and brain morphogenesis are actively occurring postnatally in the opossum, galanin (GAL) may be playing a role in the differentiation of specific regions of the brain;In the second study we used autoradiography to investigate the distribution ...


Trends In The Perceptions Of Graduates Of The Agricultural Mechanization Program At Iowa State University And Their Employers , Richard Wayne Steffen Jan 1993

Trends In The Perceptions Of Graduates Of The Agricultural Mechanization Program At Iowa State University And Their Employers , Richard Wayne Steffen

Retrospective Theses and Dissertations

The purpose of this study was to determine trends in the characteristics and perceptions of graduates of the Agricultural Mechanization program at Iowa State University to provide guidance to the faculty for the improvement of the program;The study synthesized data from three previous follow-up studies and analyzed the data using trend study methodology. It also sought to determine trends in the perceptions of the graduates' employers of the graduates' training;The overall trend found was that of consistency. Few changes in the perceptions and characteristics of graduates and their employers were found for most of the variables examined;The ...


Agricultural Reforms In Lithuania: Implications For Rural Women, Farmers And Municipalities , Caroline Schipper-Peters Jan 1993

Agricultural Reforms In Lithuania: Implications For Rural Women, Farmers And Municipalities , Caroline Schipper-Peters

Retrospective Theses and Dissertations

Lithuania is confronted with a period of profound change in agricultural structures and rural society. Efforts to privatize agriculture, and to bring the existing enterprises in line with the conditions of the market economy, create new opportunities and constraints for all parties. This research directs attention to the role and activities of various types of farmers, municipal officials, and rural women in the transformation process;Three different levels of change are taken into account: the macro level of the Lithuanian government's redefined role in economic and agricultural restructuring; the meso level of local and regional municipal officials' responses to ...


Molecular Cloning And Characterization Of 3-Methylcrotonyl-Coa Carboxylase From Soybean , Jianping Song Jan 1993

Molecular Cloning And Characterization Of 3-Methylcrotonyl-Coa Carboxylase From Soybean , Jianping Song

Retrospective Theses and Dissertations

A cDNA clone and genes coding for the 85 kDa biotin-containing polypeptide of soybean has been isolated and sequenced. This 85 kDa polypeptide has been identified as the biotin-containing subunit of 3-methylcrotonyl-CoA carboxylase (MCCase). This is the first plant gene coding for a biotin-containing enzyme to be cloned. It is also the first time that the primary sequence of the biotin-containing subunit of MCCase has been determined;The deduced amino acid sequence of the biotin-containing subunit of MCCase of soybean shows high homology with other known biotin-containing enzymes. Amino acid sequence homology between the soybean MCCase and other biotin enzymes ...


Ruminal Microbial Colonization And Digestion Kinetics Of Corn Stover As Affected By Chemical Treatment And Nitrogen Supplementation , Tito Efrain Diaz-Munoz Jan 1993

Ruminal Microbial Colonization And Digestion Kinetics Of Corn Stover As Affected By Chemical Treatment And Nitrogen Supplementation , Tito Efrain Diaz-Munoz

Retrospective Theses and Dissertations

Samples of corn leaves, cornstalks, and alkaline hydrogen peroxide(AHP)-treated cornstalks were incubated in situ for 0 to 48 h in the rumen of a fistulated cow fed alfalfa hay. Cellulase from microorganisms attached to undigested residues was extracted and assayed using either trinitrophenol-cellulose (TNP-C) or carboxymethylcellulose (CMC) as substrates. Enzymatic hydrolysis of TNP-C was linear with enzyme concentration and time and did not release free TNP. Correlations between the amount of neutral detergent fiber (NDF) digested per h and the specific activity of cellulase from ruminal microorganisms attached to corn leaves, cornstalks and AHP-treated cornstalks at each incubation ...


Protein S-Thiolation In Cultured Hepatocytes And Human Neutrophils , Yuh-Cherng Chai Jan 1993

Protein S-Thiolation In Cultured Hepatocytes And Human Neutrophils , Yuh-Cherng Chai

Retrospective Theses and Dissertations

Protein S-thiolation was characterized in cultured hepatocytes treated with t-butyl hydroperoxide, menadione and phorbol diester-stimulated neutrophils. A similar group of soluble proteins was quickly S-thiolated in oxidant-treated hepatocytes and glutathione contributed at least 90% of the total protein-bound thiols. In hepatocytes treated with 0.5 mM t-butyl hydroperoxide, 0.2 mM menadione or 10[superscript]6 neutrophils, the maximum amount of protein-bound thiols was shown to be approximately 10%, 24% and 8% of cellular glutathione respectively bound to proteins. The most abundant S-thiolated 30 kDa protein in hepatocytes was identified as carbonic anhydrase III in all cases. In oxidant-treated cells ...


Influence Of Diet Composition And Training On Energy Utilization By Greyhound Skeletal Muscle , Jennifer Drisko Baumhover Jan 1993

Influence Of Diet Composition And Training On Energy Utilization By Greyhound Skeletal Muscle , Jennifer Drisko Baumhover

Retrospective Theses and Dissertations

The relationship between diet and skeletal muscle metabolism in greyhounds was evaluated in a two-part study. Part I examined glycogen content and activities of phosphofructokinase, citrate synthase, and glutamate-pyruvate transaminase in exercised greyhounds fed a meat-mixed field diet or a corn-soy-based diet for 16 weeks. All dogs ran 5/16 mile at maximal speed twice a week. Biceps femoris muscle biopsies were collected at 0, 8, and 16 weeks. Greyhounds fed the corn-soy-based diet had significantly elevated (P ≤ 0.05) citrate synthase activity at 8 weeks (36.1 ± 5.6 [mu] mol· min[superscript]-1· g[superscript]-1wwt) compared with ...


A Theoretical And Financial Analysis Of Pork Production Contracts , Chris Lynn Hillburn Jan 1993

A Theoretical And Financial Analysis Of Pork Production Contracts , Chris Lynn Hillburn

Retrospective Theses and Dissertations

A theoretical model of pork production contracts using the principal-agent framework is used to investigate optimal compensation schedules for both feeders and owners. The optimal compensation schedules derived may take on a variety of forms, but all payment schedules should contain an inverse relationship between the quality and quantity of inputs provided by the owner and the compensation provided to the feeder;A simulation analysis is used to investigate the risk and returns to both the feeder and the owner for feeder pig finishing and feeder pig production contracts. For the owner the returns from a contract are similar (though ...


An Anatomical, Ultrastructural, Autoradiographic, And Cytophotometric Study Of Early Embryo, Endosperm, And Ovule Development In Soybean (Glycine Max L Merr) , Mark Alan Chamberlin Jan 1993

An Anatomical, Ultrastructural, Autoradiographic, And Cytophotometric Study Of Early Embryo, Endosperm, And Ovule Development In Soybean (Glycine Max L Merr) , Mark Alan Chamberlin

Retrospective Theses and Dissertations

Various aspects of early embryo, endosperm, and ovule development are described in soybean utilizing techniques in autoradiography, cytophotometry, image analysis, and light and electron microscopy. Pollen tube passage to the egg is facilitated by the break down of nucellar cells subtending the abfunicular synergid and degeneration of the latter prior to fertilization. Autoradiographic evidence indicates that the accumulation of [superscript]14C label assimilates within the ovular tissues is spatially and temporally regulated. At the zygote through proembryo stages, labeled assimilates enter the embryo sac micropylarly via the wandlabrinthe and chalazally via the hypostase. Nutrient movement into the lateral regions of ...


A Framework For Incorporating Indigenous Knowledge Systems Into Agricultural Research And Extension Organizations For Sustainable Agricultural Development In India , Bhakthavatsalam Rajasekaran Jan 1993

A Framework For Incorporating Indigenous Knowledge Systems Into Agricultural Research And Extension Organizations For Sustainable Agricultural Development In India , Bhakthavatsalam Rajasekaran

Retrospective Theses and Dissertations

The purpose of this study was to formulate a methodological framework to incorporate indigenous knowledge systems into agricultural research and extension organizations for sustainable agricultural development in India. Indigenous knowledge systems (IKSs) were recorded using farmer participatory methods such as transecting, participant observations, and unstructured interactions. IKSs were classified into (a) decision making systems; (b) indigenous knowledge statements; and (c) indigenous technical practices. Followed by this, an instrument was developed to identify: (1) the extent to which selected indigenous decision-making systems are agreeable to farmers; (2) the extent to which statements regarding indigenous knowledge systems are believed to be true ...


Optimization Of Separation And Detection Schemes For Dna With Pulsed Field Slab Gel And Capillary Electrophoresis , David Arthur Mcgregor Jan 1993

Optimization Of Separation And Detection Schemes For Dna With Pulsed Field Slab Gel And Capillary Electrophoresis , David Arthur Mcgregor

Retrospective Theses and Dissertations

The purpose of the Human Genome Project is outlined followed by a discussion of electrophoresis in both slab gels and capillaries and its application to deoxyribonucleic acid (DNA). Techniques used to modify electroosmotic flow in capillaries are also addressed. Several separation and detection schemes for DNA via gel and capillary electrophoresis are described. Emphasis is placed on the elucidation of DNA fragment size in real time as well as shortening separation times to approximate real time monitoring;First, the migration of DNA fragment bands through a slab gel can be monitored by UV absorption at 254 nm and imaged by ...


Tissue-Specific Regulation Of 1,25-Dihydroxyvitamin D Action In The Target Tissues Of Rats , Matthew John Beckman Jan 1993

Tissue-Specific Regulation Of 1,25-Dihydroxyvitamin D Action In The Target Tissues Of Rats , Matthew John Beckman

Retrospective Theses and Dissertations

Tissue response to 1,25(OH)[subscript]2D[subscript]3 action was evaluated by examining vitamin D-dependent VDR, 24-OHase, and CaBP mRNA expressions, 24-OHase activities, and VDR concentrations in kidney and intestine. Of 4 groups of rats, 2 groups were fed an adequate vitamin D (300-600 IU/wk), 1.0-1.2% calcium (Ca) diet, designated NC, and 2 groups were fed an adequate vitamin D, 0.02% Ca diet, designated LC. One group from each diet was treated with excess vitamin D[subscript]3 (75,000 IU/wk). These groups were designated NCT and LCT, respectively;Plasma 1,25(OH ...


Modulation Of Excitatory Synaptic Transmission In The Rat Spinal Dorsal Horn , Rok Cerne Jan 1993

Modulation Of Excitatory Synaptic Transmission In The Rat Spinal Dorsal Horn , Rok Cerne

Retrospective Theses and Dissertations

Modulation of excitatory amino acid (EAA)-mediated synaptic transmission in the rat spinal dorsal horn by the cyclic adenosine 3[superscript]',5[superscript]'-monophosphate (cyclic AMP)-dependent second-messenger system and by the activation of metabotropic glutamate receptors has been investigated by using sharp-electrode voltage recording in the transverse spinal cord slice preparation and whole-cell voltage-clamp recording from acutely dissociated dorsal horn neurons;The elevation of intracellular concentration of cyclic AMP by membrane permeable analog, 8-Br cyclic AMP, and application of phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine (IBMX), depolarize rat spinal dorsal horn neurons. In addition they enhance presumed monosynaptic excitatory postsynaptic potentials evoked ...


Cloning, Sequencing, And Expression Of Brucella Abortus Heat Shock 70 Gene , Emily C. L. Chin Jan 1993

Cloning, Sequencing, And Expression Of Brucella Abortus Heat Shock 70 Gene , Emily C. L. Chin

Retrospective Theses and Dissertations

Brucella abortus is a gram negative bacteria that can infect and cause serious disease in many mammals including humans. Any organism, including Brucella, that can survive as an intracellular parasite must be able to survive the stress of a foreign and often hostile environment of the host. Stress usually results in a dramatic change in gene expression including an elevated synthesis of heat shock proteins;We have subcloned, sequenced and expressed the Brucella HSP70 and the upstream sequences. The gene was put under the control of the strong "tac" promoter. However, when expressed, we saw a high accumulation of a ...


True Digestibilities Of Amino Acids And Protein In Pigs Using 13c As A Label To Determine Endogenous Amino Acid Excretion , Roger Alan Arentson Jan 1993

True Digestibilities Of Amino Acids And Protein In Pigs Using 13c As A Label To Determine Endogenous Amino Acid Excretion , Roger Alan Arentson

Retrospective Theses and Dissertations

Two experiments were conducted to study the use of [superscript]13C abundance to partition ileal digesta protein into undigested feed and endogenous portions. In both experiments, pigs were fed diets consisting of corn-corn gluten meal-crystalline amino acids or wheat-soybean meal during a growing phase. The corn-corn gluten meal diets contained feedstuffs from C[subscript]4 plants and the wheat-soybean meal diets contained feedstuffs from C[subscript]3 plants. C[subscript]4 plants have delta [superscript]13C values of -13.5 ± 1.5\perthous and C[subscript]3 plants have delta [superscript]13C values of -28.1 ± 2.5\perthous. Three ...


Soil Compaction Loosener , Kamal Mohamed Adam Jan 1993

Soil Compaction Loosener , Kamal Mohamed Adam

Retrospective Theses and Dissertations

Soil compaction is a potential problem in many agricultural soils due to the increasing mass of agricultural vehicles and equipment and tendency of farmers to work fields when soil is wet. A review of literature showed that some control measures can be taken such as controlling traffic to reduce compaction or use of tillage to remove the effects of compaction. Many implements have been used to loosen compacted soil, but in their design compaction depth was not considered and also these implements are designed for full width tillage as opposed to tillage only in the zone that has been compacted ...