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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Tetrodotoxin-resistant sodium channels in neuropathic pain /

Fjell Hjelmström, Jenny, January 1900 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 6 uppsatser.
22

The interaction of Puccinia striiformis with wheat and barley

Garrood, Jacqueline Mary January 2001 (has links)
No description available.
23

THE ROLE AND REGULATION of MITOCHONDRIAL DYNAMICS IN CISPLATIN RESISTANCE IN HUMAN GYNECOLOGIC CANCER CELLS

Kong, Bao January 2015 (has links)
Cervical cancer (CECA) and ovarian cancer (OVCA) rank first and third in the number of new cases diagnosed among gynecologic cancers,and chemoresistance severely limits their treatment success. The underlying mechanism of chemoresistance is multi-factorial and partly due to defects in drug-induced apoptosis. Cisplatinum (CDDP) -induced, p53-mediated mitochondrial cell death is controlled by Akt and is a determinant of chemosensitivity in gynecologic cancer cells. Mitochondria dynamics (fusion and fission) are involved in the regulation of mitochondria-mediated apoptosis. The tumor suppressor prohibitin 1 (Phb1) is involved in long from Opa1 (L-Opa1) processing and p53-regulated apoptosis. Whether mitochondrial fusion protein Opa1 and its protease Oma1 as well as Phb1 are involved in the regulation of chemoresistance in CECA and OVCA cells are not known. The overall objective of my research is to increase the current understanding on the regulation of mitochondrial dynamics and on its role in chemoresistance in gynecologic cancer cells. We hypothesize that CDDP induces Phb1 binding to phosphorylated p53 (p-p53) and Bak, resulting in Bak activation and mitochondrial outer membrane permeabilization (MOMP). These responses also induce Oma1-mediated Opa1 processing, mitochondrial fragmentation and apoptosis but are inhibited by high Akt level in chemoresistant cells. Here we present evidence that CDDP induces Oma1 activation, L-Opa1 processing and mitochondrial fragmentation in chemosensitive but not in chemoresistant cells. Silencing p53 expression attenuated CDDP-induced L-Opa1 loss, mitochondrial fragmentation and apoptosis in chemosensitive cells, while reconstitution of p53 in p53-deficient (mutant or null) chemoresistant cells induced Oma1 activation, L-Opa1 processing and changes in mitochondrial dynamics irrespective of the presence of CDDP. In response to CDDP, p-p53 (ser15) dissociates Phb1 from Opa1-Phb1 complex and binds to Bak in chemosensitive but not chemoresistant cells. Inhibition of Akt is required for CDDP to induce L-Opa1 processing, mitochondrial fragmentation and apoptosis in chemoresistant cells. Our study suggests a mechanism that p53 regulates L-Opa1 processing and mitochondrial fragmentation in chemosensitive cells induced by CDDP, while this pathway is suppressed in chemoresistant cells. Dysregulated mitochondrial dynamics may in part be involved in the pathophysiology of CDDP resistance. Inhibiting Akt activity and inducing Opa1 processing may serve as novel therapeutic strategies for these gynecologic cancers.
24

Hegemony has his hand up again : examining masculinities and resistance when teaching about gender

Moore, Shannon Dawn Maree 11 1900 (has links)
This paper outlines interview based, qualitative research that was conducted with six male youth who were previously students in my Social Studies 11 class. Within two separate, semi-structured interviews, participants were asked to discuss student resistance to anti oppressive pedagogy that focused on gender, and their understanding of masculinities. The initial purpose of this research was to find a relationship, if any, between acts of student resistance and the construction of masculinities. Participant perceptions of masculinities evolved as the dominant theme within the interviews. These discussions revealed that student understandings of masculinity were often entrenched in hegemonic language, yet contradictions were exposed between their rote definitions and personal narratives. Further, the use of media as a discourse became a venue for complicating essentialist understandings of masculinity, and for exposing multiple, fluid, versions of masculinities. Within these discussions of multiplicity, race and sexuality became two intersections of identity that took precedence. Also the intersection of teacher identity and the reading of identity terms emerged as a salient interpretation for gender discussions in the classroom. Throughout this write-up of the research are methodological considerations surrounding power, the construction of masculinity and race, and the further entrenching of heteronormativity, in the form of methodological interludes. Finally, within the conclusion, I consider the implications for practice and future directions for research in masculinities. / Education, Faculty of / Curriculum and Pedagogy (EDCP), Department of / Graduate
25

Transferring blackleg resistance from Brassica carinata and synthetic hexaploid Brassica accessions into Brassica napus

Wang, Duoduo 11 April 2016 (has links)
Blackleg caused by Leptosphaeria maculans (Desm.) Ces. & De Not. is one of the most serious diseases in canola production. A high level of blackleg resistance has been shown in Brassica carinata A. Braun (BBCC) and new synthetic hexaploid Brassica species (AABBCC) developed from the crosses of B. rapa L. and B. carinata. Blackleg resistance from B. carinata and hexaploid Brassica accessions was transferred into B. napus L. using interspecific hybridization followed by backcrossing to a susceptible B. napus cultivar ‘Westar’ three or four times and selfing one or two times to produce pure lines. Leptosphaeria maculans isolate 03-15-03 was used to select the resistant plants in each generation using cotyledon inoculation, and four L. maculans isolates (03-15-03, 3-42-6, 09stonewall9553, and PG4-1-M) were utilized in advanced generations. In the cross of B. napus ‘Westar’ and B. carinata, all plants in the F1 showed a high level of resistance to L. maculans isolate 03-15-03. According to the chi-square testing for goodness of fit, the segregation of resistant and susceptible plants fit a 1:1 ratio in the BC1, BC3, and BC4. In the BC3F2, two families followed a 3:1 segregation ratio of resistant and susceptible plants. The results suggest that the resistance to L. maculans transferred from B. carinata into canola ‘Westar’ was controlled by a single locus. Embryo rescue tissue culture was used to obtain F1 plants of the crosses of ‘Westar’ and synthetic hexaploid Brassica accessions. In the BC1 and BC2, most families did not fit a 1:1 segregation ratio of resistant and susceptible plants. The segregation of resistant and susceptible plants fit a 3:1 ratio when inoculated with L. maculans isolates in the BC1F2-3.1.1s and BC1F3-3.1.1.1ss families. Meanwhile, the BC2-3.1.1 family also followed a 1:1 segregation of resistant and susceptible plants inoculated with L. maculans isolate 03-15-03. The results suggest that the resistance to L. maculans introgressed from synthetic hexaploid Brassica species into B. napus is most likely controlled by a single locus. / May 2016
26

Horizontal Transfer of β-Lactam Resistance in the Mouse Gut Microbiota Under Antibiotic Treatment

Laskey, Alexander 05 November 2020 (has links)
The rise of β-lactam-resistant bacteria from agricultural settings, including food-producing animals and their related food products has become a significant public health concern. Consumption of food contaminated by such bacteria may cause infection as well as the transmission of resistance genes. Here we used a mouse model to assess the impact of different antibiotic treatments on the composition of the gut microbiota and any impact on the transfer of β-lactam resistance genes between donor and recipient bacteria. Mice were inoculated with β-lactam resistant Escherichia coli and an antibiotic-susceptible Salmonella Heidelberg strain. The mice were treated with either streptomycin, ampicillin or both antibiotics. Mouse feces were collected at regular intervals and processed using selective culture techniques to capture potential transfer of resistance genes. Gene transfer was confirmed by whole genome sequencing. DNA extracted from the feces was used for monitoring changes in microbial profiles by 16S rDNA sequencing. In the absence of antibiotic treatment, the inoculated bacteria were only transiently detected and no transconjugants were recovered from the mouse feces. In comparison, antibiotic treatment changed microbial profiles in the mouse gut, enhanced colonization of the bacterial isolates, and facilitated the transfer of the resistance genes into both S. Heidelberg and commensal E. coli recipient strains. The results of this study indicated that the use of multiple antibiotics may enhance infection of opportunistic β-lactam resistant bacterial pathogens relative to single antibiotics and pose a greater risk in terms of antibiotic resistance gene transfer. Such process might occur in clinical settings where patients are under prolonged antibiotic treatments. Information gained through this study together with future work will inform the development of new policies guiding the prudent use of antibiotics.
27

Quantitative evaluation of relative insecticide resistance of Lygus hesperus Knight

Chaudhry, Umruddin, 1927- January 1960 (has links)
No description available.
28

Genetics of drug resistance in malaria : identification of genes conferring chloroquine and artemisinin resistance in rodent malaria parasite Plasmodium chabaudi

Modrzynska, Katarzyna Kinga January 2011 (has links)
Resistance to antimalarial drugs continues to be a major obstacle in controlling and eradicating malaria. The identification of genetic markers of resistance is vital for disease management but they can be difficult to predict before resistance arises in the field. This thesis describes an alternative approach to gene identification, combining an in vivo experimental evolution model, Linkage Group Selection (LGS) and Solexa genome re-sequencing. Here this model was used to resolve the genetic basis of chloroquine and artemisinin resistance in the rodent malaria parasite Plasmodium chabaudi. AS-30CQ is a parasite with high resistance to chloroquine and resistance to artemisinin. It was crossed with the genetically different drug-sensitive strain AJ. The resulting progeny were selected with drugs and backcrossed to the sensitive parent. Both crosses were treated with increasing concentrations of chloroquine and artemisinin. The frequency of markers from the sensitive parasite were analysed in order to characterize the signatures of drug selection. Three loci involved progressively in chloroquine resistance were identified on chromosomes 11, 3 and 2. One main locus on chromosome 2 was identified with artemisinin selection. The Solexa platform was used to re-sequence the genomes of both AS-30CQ and its sensitive progenitor, AS-sens. The differences between the two genomes were integrated with the LGS data to identify: 1) a strong candidate for the main CQresistance determinant - a putative amino acid transporter on chromosome 11 (aat1) 2) two candidates for high level chloroquine resistance on chromosome 3. and 3) a mutation in ubp1 gene on chromosome 2 that is likely to contribute to the highest level of chloroquine resistance and be main determinant of the artemisinin resistance phenotype. In addition the last section of this thesis describes two otherwise isogenic clones showing low- and high levels of chloroquine resistance were grown competitively to evaluate the effect of these mutations on parasite fitness. The highly resistant strain demonstrated a loss of fitness in relation to its more sensitive progenitor and was outcompeted in untreated and low-treated infections.
29

Isolation and characterization of potential indicator bacteria to be used for validation of Escherichia coli O157:H7 reduction in beef slaughter plant critical control points

Magana Yepez, Maria Belem 01 November 2005 (has links)
Microbiological detection of foodborne pathogens is ineffective for monitoring critical control points (CCP) within a slaughter/processing Hazard Analysis and Critical Control Point (HACCP) system. Pathogens are usually absent from carcass surfaces and their uneven distribution makes it difficult to obtain a representative sample. However, microbiological testing can be applied within a HACCP plan to validate and verify the effectiveness of decontamination procedures designed to control hazards. With proper data collection, the reduction of an indicator group at a point in processing can indicate that a specific pathogen is being effectively controlled, especially when pathogen levels are too low to allow confirmation of process control, as they typically are in beef slaughter processing. Since E. coli O157:H7 has been shown to have some acid resistance, the ability of typical indicator organisms to accurately predict the reduction of this pathogen by carcass decontamination procedures has been a concern. Obtaining potential indicator bacteria from the same environmental reservoir as E. coli O157:H7 may provide non-pathogenic indicators with similar heat- and acid-resistance characteristics suitable for use in processing plant environments for validation and verification of carcass decontamination treatments within HACCP plans. Potential indicator bacteria were isolated from hides of cattle at slaughter facilities in Arizona, Georgia, and Texas and compared with isolates of E. coli O157:H7 from the same locations to determine similarity in acid- and heat-resistance characteristics. After evaluation at 2 heating temperatures (55 and 65??C) and 3 pH levels (3.0, 4.0, and 5.0), it was determined that several potential indicator bacteria were slightly more resistant than E. coli O157:H7 to heating and acid treatment. The greatest reduction in numbers for E. coli O157:H7 and indicator bacteria occurred at pH 3.0 and temperature of 65??C. Counts of bacteria grown at pH 4.0 and 5.0 were not significantly different. Testing indicated that several of the isolates from cattle hides would make good process control indicators since the indicator bacteria were reduced by heating or acid conditions at similar or greater rates when compared to E. coli O157:H7, providing an increased level of security that pathogens have been reduced in processing.
30

A study using in vitro selection to develop herbicide resistance in Lotus corniculatus /

MacLean, Nancy L. January 1985 (has links)
No description available.

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