• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 34
  • 7
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 78
  • 49
  • 47
  • 46
  • 14
  • 14
  • 13
  • 12
  • 11
  • 11
  • 10
  • 10
  • 9
  • 8
  • 8
  • 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

Development of Virus Vectors and CRISPR Tools for Soybean Functional Genomics

Zaulda, Fides Angeli January 2021 (has links)
No description available.
22

Computational Analysis of MAP3K Kinases across Plant Genomes and Functional Characterization of a Subset of MAP3Ks in Nematode Resistance

Bokros, Nobert Tamas 14 December 2018 (has links)
Plant MAP3Ks have expanded significantly compared to their metazoan counterparts. A new, sequential workflow combining multispecies ortholog clustering and newly built, family-specific HMMs is used to identify the MAP3K gene family within seven plant species, allowing for a refinement of previously proposed gene family cladding and the novel identification of the MAP3K gene families in the allotetraploid cotton Gossypium hirsutum and newly sequenced monocot seagrass Zostera marina. The MAP3K gene family architecture is further refined and validated using bioinformatics analyses before the recently characterized Arabidopsis Raf-like MAP3K ILK1 is identified and characterized in upland cotton. Transient gene silencing reveals an increase in RKN susceptibility following GhILK1.1 silencing in the susceptible TM1 cultivar. No changes in susceptibility were seen in the resistant M240 cultivar or against reniform nematodes. GhILK1.1 is only the second cotton gene characterized to have a direct role in mediating RKN resistance.
23

Impacts of cover crop, soil steaming, and plastic mulch on field-grown tomato production and virus-induced gene silencing in Antirrhinum, Penstemon, Petunia, Rosa, and Rudbeckia

Breland, Brenton Andrew Earl 08 August 2023 (has links) (PDF)
Weeds and soil-borne diseases can cause large yield losses in field-grown tomato (Solanum lycopersicum) production. Techniques have been developed to reduce soil-based problems. In this study, we evaluated the impacts of cover crops, soil steaming, and plastic mulch to reduce weed and disease pressure in field-grown tomatoes. Four cover crop treatments were grown in the fall and winter before spring planting. Soils were steamed to a target temperature of 71.1 °C for 0, 5, or 20 minutes. Plastic mulch was also used on half of the rows. Yield, weed densities, and disease incidence were recorded. Reduced flowering time and stringent flowering requirements may reduce the ability to conduct crosses in many plants. Many factors control flowering. Terminal Flowering Locus 1 (TFL1) inhibits flower development. In this study, we attempted to transiently downregulate TFL1 via virus-induced gene silencing (VIGS) in Antirrhinum, Penstemon, Petunia, Rosa, and Rudbeckia.
24

Functional Gene Analysis of Resistance QTL towards <i>Phytophthora sojae</i> on SoybeanChromosome 19

Stasko, Anna K. 10 August 2018 (has links)
No description available.
25

Evaluation of the effectiveness of the resilient educators support programme among HIV and AIDS affected educators in Gauteng

Van der Waal, Wya Aike 28 September 2010 (has links)
The Resilient Educators support programme (REds) for HIV and AIDS affected educators was initiated by the University of the Northwest in 2006, following a research project in 2005 that highlighted the need for a support programme that addresses the challenges of educators affected by HIV and AIDS, as existing support structures were found to be inadequate. The REds programme is implemented in phases, and after the completion of each phase, the programme is modified to meet the needs of a broader audience of educators. Since 2006, the REds programme has been implemented by independent researchers in four South African provinces, Gauteng, Mpumalanga, the Northwest province and the Free State. This round of implementation included a comparison group, to allow researchers to compare data. The 2009 implementation of the REds programme was aimed at gathering comparative data to prove that the programme has a positive impact on the quality of life and resilience of educators. This was done in order to provide to the greater REds programme the opportunity to generalise the findings of the programme, and implement it on a national level. The goal of this study was to evaluate the effectiveness of the 2009 version of the REds programme to enhance the quality of life and resilience of HIV and AIDS affected educators in Gauteng. For the purpose of this research study, the researcher used applied and evaluative research. The mixed methods research approach was used, followed by the concurrent triangulation design. The qualitative and quantitative data carried the same weight in the results of the study, and the data sets were merged in the interpretation to produce well-validated conclusions. When comparing the pre- and post-test results, both the quantitative and qualitative data were used to prove or disprove the hypothesis. For the quantitative part of the study, the researcher made use of a quasi-experimental design namely the comparison group pre-test-post-test design. For the qualitative part of the study, the researcher used a collective case study design. Quantitative data was collected through two group administered standardised questionnaires, the Professional Quality of Life Screening (ProQol) and the Resilience Scale for Adults (RSA). Qualitative data was collected by using a narrative, drawings and observations. Pre-test data was collected from the experimental and comparison groups prior to exposure to the REds programme. The experimental group participated in the programme and afterwards, both the experimental and comparison groups participated in a post-test. The participants were recruited from the Diepsloot Combined School and the Emfundiswene Primary School in Alexandra, Johannesburg, Gauteng, by using non-probability volunteer sampling. The quantitative empirical research findings in the experimental group data showed minimal differences between the pre- and post-test data for the ProQol test, and trivial differences in the RSA screening. The comparison group data also showed minimal differences, but the differences were in a downward trend. When comparing the experimental and comparison group findings, the experimental group’s results were slightly more positive than the comparison group, but not enough to draw valid conclusions. However, the qualitative findings showed that the participants in the experimental group found that the programme addressed their support needs as HIV and AIDS affected educators and they felt empowered with knowledge and skills that they lacked, thus making them more resilient. The researcher did not mark any changes in the comparison group data, thus indicating that they did not feel empowered. The researcher hypothesised the following: If the Resilient Educators support programme (REds) were implemented among HIV and AIDS affected educators, their quality of life and resilience will be increased. Conclusions drawn from the qualitative research findings indicated that the REds programme met the support needs of HIV and AIDS affected educators, as the experimental group indicated that they felt empowered and the comparison group did not indicate this. The quantitative data results were not significant enough to prove or disprove the proposed hypothesis, and thus the researcher recommends that the reasons for the insignificant test results from the questionnaires be investigated. AFRIKAANS : Die Resilient Educators Support Programme (REds), ’n ondersteunings program vir MIV-en VIGS-geaffekteerde opvoeders, is in 2006, deur die Noordwes-Universiteit ontwikkel. Die projek spruit uit navorsing wat in 2005 gedoen is en getoon het dat die uitdagings wat MIV-en VIGS-geaffekteerde opvoeders in die gesig staar nie aangespreek word deur die huidige ondersteuningstrukture nie, en dat daar ’n daadwerklike behoefte aan ’n ondersteuningsprogram bestaan. Die REds-program word in fases geïmplementeer, en in elke fase, word die program heraangepas om aan die behoeftes van ’n breër teikengehoor van opvoeders te voldoen. Sedert die begin van die projek in 2006, is die REds-program deur verskeie onafhanklike navorsers, in vier Suid Afrikaanse provinsies, Gauteng, Mpumalanga, Noordwes en die Vrystaat geïmplementeer. Die 2009-implementering van die REds-program, het ’n vergelykende groep ingesluit, wat navorsers instaat stel om die data wat ingesamel word te vergelyk met ’n groep wat nie ’n intervensie ontvang het nie. Die 2009-implementering van die REds-program se doel was om vergelykbare data in te samel, en sodoende te bewys dat die program ‘n positiewe impak op die lewensgehalte en veerkragtigheid van opvoeders het. Die doel van hierdie studie was om te evalueer hoe doeltreffend die 2009-weergawe van die REds-program die lewenskwaliteit en veerkragtigheid van MIV-en VIGS geaffekteerde opvoeders in Gauteng verbeter. Vir die doeleindes van hierdie navorsing het die navorser toegepaste en evaluerende navorsing benut. Die gemengdemetode-navorsingsbenadering en die samewerkende triangulasie-ontwerp is benut. Die kwantitatiewe en kwalitatiewe data dra ewe veel gewig in die resultate van die studie. Datastelle is ook saamgevoeg tydens die interpretasie daarvan ten einde deeglik gestaafde gevolgtrekkings te maak. Tydens die vergelyking van die voor- en na-toetsresultate, is die kwantitatiewe en kwalitatiewe data benut om die hipotese te bewys of te weerlê. Vir die kwantitatiewe deel van die studie het die navorser ‘n kwasieksperimentele ontwerp, genaamd die groep-vergelykende voor-toets-na-toetsontwerp benut. Die kwalitatiewe deel van die studie is gedoen met behulp van die kollektiewe gevallestudie-ontwerp. Kwantitatiewe data is verkry deur twee groepgeadministreerde gestandaardiseerde vraelyste, die Professional Quality of Life Screening (ProQol) en die Resilience Scale for Adults (RSA), te gebruik. Kwalitatiewe data is ingesamel deur gebruik te maak van ’n narratief, tekeninge en observasies. Voor-toets-data is ingesamel by die eksperimentele en vergelykende groep. Die eksperimentele groep het die die REdsprogram deurloop en beide groepe het daarna deelgeneem aan die na-toets. Die deelnemers van die Diepsloot gekombineerde skool en die Emfundiswene laerskool in Alexandra, Johannesburg is by wyse van ’n nie-waarskynlikheids steekproeftrekking gekies, deur van die vrywillige steekproeftegniek gebruik te maak. Die kwantitatiewe navorsingsbevindinge van die eksperimentele groep het minimale verskille tussen die voor- en na-toets-data getoon vir die ProQol-toets, en niksbeduidende verskille is opgemerk in die RSA-toets. Die vergelykende groep se data het ook minimale verskille tussen die voor- en na-toets getoon, maar hierdie veranderings was negatief. In ’n vergelyking tussen die eksperimentele en vergelykende groep se resultate, is bevind dat die eksperimentele groep se uitslae meer positief van aard was as die van die vergelykende groep. Hierdie verskil is egter so klein dat geen werklilke gevolgtrekkings gemaak kan word nie. Desnieteenstaande het die kwalitatiewe bevindinge getoon dat die program wel aan die eksperimentele groep se ondersteuningsbehoeftes voorsien het. Die deelnemers het aangedui dat hulle bemagtig is met die kennis en vaardighede wat hul benodig om hul veerkragtigheid te verhoog. Die navorser het egter geen veranderinge in die vergelykende groep se data waargeneem nie, wat dus beteken dat die vergelykende groep nie bemagtig is nie. Die navorser het die volgende hipotese geformuleer: Indien die Resilient Educators support program (REds) onder MIV-en VIGS-geaffekteerde opvoeders geïmplimenteer word, sal hul lewenskwaliteit en veerkragtigheid verbeter. Gevolgtrekkings gemaak na gelang van die kwalitatitewe navorsingsbevindinge toon aan dat die REds-program wel die ondersteuningsbehoeftes van die opvoeders aanspreek, aangesien die eksperimentele groep aangedui het dat hulle bemagtig voel, in teenstelling met die vergelykende groep wat nie bemagtig voel nie. Die kwantitatiewe navorsingsbevindinge was egter van so ’n aard dat die navorser dit nie kon benut om die hipotese waar of vals te bewys nie. Na gelang van hierdie bevinding beveel die navorser onder andere aan dat die rede(s) vir die niksseggende kwantitatiewe toetsresultate verder ondersoek word. / Dissertation (MSW)--University of Pretoria, 2010. / Social Work and Criminology / unrestricted
26

Uitgebreide rol van onderwysers in die aanspreek van die behoeftes van kinders wat weerloos gelaat is in die konteks van MIV/VIGS

Taylor, Esmari 03 1900 (has links)
Thesis (MPhil (Sociology and Social Anthropology))--University of Stellenbosch, 2009. / This thesis is about children who are vulnerable in the context of HIV/AIDS. The epidemic leaves children vulnerable in a number of ways. The education sector is confronted with vulnerable children and this has caused the roles and responsibilities of teachers to be extended. The research is aimed at determining whether teachers see a role for themselves in this context that extends beyond formal education and also to find out how teachers view this role. The research was conducted at three schools in the Llingelethu community in Malmesbury: a pre-primary school (the Siphumeze Educare Centre), a primary school (Naphakade Primary School) and a high school (Naphakade Secondary School). The research determined that teachers do feel that they have a role in this context, but there were also those who felt that other role players must rather fulfil this role. One of the most important findings of the research was that teachers often view their role in the context of HIV/AIDS in a limited way. In this regard, teachers often think only in terms of children who are infected by die virus, while not taking into account children who are affected in other ways. Teachers, as well as schools, also often still focus on their role in HIV/AIDS prevention. A further aim of the research was to determine which challenges prevent teachers from playing an extended role in the lives of vulnerable children. The participants in the research identified various challenges, including those that are a result of keeping HIV status secret, because of stigma and a lack of trust. A further challenge that was identified is a lack of background information about learners, sometimes as a result of the fact that teachers do not come from the community. Factors that make it difficult for teachers to conduct follow up work were also identified, as well as emotional exhaustion and other facors that prevent teachers from playing an extended role. A lack of support was also identified by participants as a challenge and different dimensions of support were identified.
27

GENETIC DIVERSITY OF BEAN POD MOTTLE VIRUS (BPMV) AND DEVELOPMENT OF BPMV AS A VECTOR FOR GENE EXPRESSION IN SOYBEAN

Zhang, Chunquan 01 January 2005 (has links)
Bean pod mottle virus (BPMV), a member of the genus Comovirus in the family Comoviridae, is widespread in the major soybean-growing areas in the United States. The complete nucleotide sequences of the genomic RNAs of the naturally occurring partial diploid strain IL-Cb1 were determined. Intermolecular RNA1 recombinants were isolated from strain IL-Cb1 and characterized at the molecular level. Structurally similar recombinant RNA1 was also generated after four passages in soybean derived from plants previously inoculated with a mixture of infectious RNA1 transcripts from two distinct strains. BPMV was developed as a plant viral vector that is appropriate for gene expression and virus-induced gene silencing (VIGS) in soybean. The foreign gene was inserted between the movement protein (MP) and the large coat protein (L-CP) coding regions. The recombinant BPMV constructs were stable following several serial passages in soybean and relatively high levels of protein expression were attained. Successful expression of several proteins with different biological activities was demonstrated from the BPMV vector. Double infection of soybean by BPMV and SMV triggers a synergistic interaction leading to a serious disease. To investigate the underlying mechanism, helper componentprotease (HC-Pro) genes from several SMV strains and TEV were expressed from BPMV vectors. The recombinant BPMV vectors carrying the HC-Pro genes from SMV strain G7 or TEV induced very severe symptoms on soybean whereas constructs containing the HC-Pro gene from SMV isolate P10, a mild strain with an apparent defect in synergism, induced only very mild symptoms. Transient agroinfiltration assays using GFP-transgenic Nicotiana benthamiana showed that HC-Pro from SMV isolate P10 was not a RNA silencing suppressor, whereas those of SMV strain G7 and TEV exhibited strong suppressor activities. Analysis of chimeric HC-Pro genes and point mutations indicated that a positively charged amino acid at position 144 is critical for the suppressor function of not only SMV HC-Pro but also other potyvirus HC-Pro proteins. Although amino acid substitution at position 144 resulted in changes in small RNA profile, it did not affect HC-Pro stability.
28

Genetic Analysis of Lignification and Secondary Wall Development in Bast Fibers of Industrial Hemp (Cannabis sativa)

Koziel, Susan P. 06 1900 (has links)
Industrial hemp (Cannabis sativa) is a highly productive crop that is well suited to cultivation in Canada. To better understand the development of bast (phloem) fiber secondary walls and to facilitate reverse genetics screening for improved germplasm, I undertook two sets of microarray experiments. The first compared transcript expression in stem peels at three positions along the length of the stem. The second set of microarray experiments compared transcript expression in adjacent tissue layers along the radial axis of the stem. The transcripts that were enriched in fiber-producing tissues in both studies were consistent with a dynamic program of cell wall deposition. Detailed qRT-PCR analysis of specific lignification genes identified the best targets for reverse genetics. Finally, as a first step towards establishing a virally induced gene silencing (VIGS) system, I identified viruses that produced visual symptoms of infection, although qRT-PCR failed to confirm the infection / Plant Biology
29

Application Of Virus Induced Gene Silencing Of Brachypodium Distachyon, A Model Organism For Crops

Demircan, Turan 01 June 2009 (has links) (PDF)
Grass family is most important family in plant kingdom due to intensive usage of crops in agriculture. To date, molecular biology researches on grass family have had limitations because of inappropriate characteristics of barley and wheat to conduct experiments on them. Brachypodium distachyon that belongs to grass family has recently emerged as a model organism for crops. It shares common characteristics for a model plant due to its small genome, small physical plant size, a short lifecycle, and less demanding growth requirements / as other model organisms / Arabidopsis thaliana, Oryza sativa, and Zea mays (Draper et al. 2001). Especially after appreciating, the genetic distance of O. sativa to grasses (Garvin et al. 2008), it become a key organism to understand complicated genomic organization of agriculturally valuable grasses. Virus-induced gene silencing (VIGS) is one of the revolutionary methods allowing a rapid and effective loss of a gene function through RNA interference (Holzberg et al. 2002 / Liu et al. 2008). Barley stripe mosaic virus (BSMV) is still the most effective vector used in monocot gene silencing. It has a tripartite RNA genome having a wide range of infection ability for monocots including barley, oat, wheat, and maize as host (Holzberg et al. 2002 / Scofield 2005). In this thesis, Phytoene desaturase (PDS) gene of Brachypodium distachyon was silenced via BSMV mediated VIGS. Additionally, with Green fluorescence protein (GFP) bearing BSMV transcripts, GFP expression was observed under fluorescent microscope. To our knowledge, this is the first report demonstrating a VIGS via BSMV in Brachypodium distachyon. The success of virus induced gene silencing method in Brachypodium distachyon, will be a new convenient tool for evaluating functions of crop genes in this model organism.
30

The Effect Of Virus Induced Gene Silencing Of Fas Associated Factor1 In Blumeria Graminis Infected Barley

Bozhanaj, Kreshnik 01 October 2009 (has links) (PDF)
Cereal loss due to fungal pathogens is an ongoing setback in agriculture. Elucidating plant&rsquo / s resistance and susceptibility mechanisms against these cereal killers, promises progress in agriculture. In the way of understanding barley resistance against fungus Blumeria Graminis we silenced FAS-Associated Factor 1 (FAF1) gene in its mRNA level with Virus Induced Gene Silencing (VIGS) technique. Previous research in our lab had shown an augmentation in mRNA levels of FAF1 gene in fungus infected wheat, suggesting a role of this gene in the resistance mechanism. We hypothesized that the apoptotic role of FAF1 protein in metazoan is conserved in plants by including FAF1 as a factor in hypersensitive response. Barley lines Pallas01 and Pallas03 which are respectively resistant and susceptible against fungus Blumeria graminis hordei 103 (Bgh103) were used for fungal inoculations after FAF1 silencing, to test if the hypersensitive response against fungus Bgh103 was prevented. In this aspect the formation of death lesions on the Pallas01 leaf due to fungal resistance was not prevented demonstrating that FAF1 silencing with VIGS in the resistant Pallas01 line of barley is not sufficient to stop apoptosis. On the other hand the FAF1-silenced barley susceptible line Pallas03 became more sensitive to fungal stress based on conidia (body part of the fungus) counting after trypan blue staining of the infected leaves. In the C-terminus of FAF1 an ubiquitin like domain-X (UBX) is found, which is the cause of stress sensitivity based on the reported data obtained about this domain&rsquo / s loss of function in other proteins. These results suggest that FAF1 is a catalyst in the hypersensitive response and its loss of function makes barley more susceptible to fungal stress. On the other hand a short mRNA homology was found among FAF1 and many pathogen disease related proteins making this homology a possible target site for VIGS of FAF1 generated siRNAs, which might cause some other protein to be responsible for the barley susceptibility against the fungus.

Page generated in 0.0599 seconds