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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

Molecular marker analysis of cultivated sunflower (Helianthus annus L.)

Berry, Simon January 1995 (has links)
No description available.
22

The cell biology and physiology of cytoplasmic male sterility in Petunia hybrida

Liu, Xiaochuan January 1989 (has links)
No description available.
23

Static Chaos: The Great War and Modern Novels of Sterility

Stoeckl, Sarah, Stoeckl, Sarah January 2012 (has links)
The Great War was unprecedented both in its devastation and in the significance people attached to it, which this dissertation contends led to a crisis of representation that manifested in literary tropes and discourses of sterility. Some authors used sterility to represent the war as a cultural and historical apocalypse, others as a basis for questioning how literature, Western civilization, and humanity itself could continue after such a catastrophe. "Static Chaos" theorizes how thematic renderings of sterility work alongside modernist formal experimentation to sever reproductive literary traditions. The widespread instances of sterility reveal the deep effects of the war on non-combatants as well as combatants, as demonstrated through analysis of novels by a diverse group of authors from Britain and United States--Rebecca West, Willa Cather, Ernest Hemingway, Claude McKay, and Ford Madox Ford. The study moves chronologically yet it also follows a narrative logic of thwarted human sexual experience beginning with novels focused upon problematic virginity, then those depicting the inability or unwillingness to procreate, and then one preoccupied with pregnancy overshadowed by illegitimacy and stillbirth. This dissertation draws upon trauma theory and grief and mourning theory, which reveal how, in addition to individual experiences of psychological trauma, the war disabled traditional means of coping, leading to a widespread inability to mourn that was traumatizing in itself. I name this state "traumatic grief" and argue that its pervasiveness led authors to break with a longstanding interconnection between making war and making babies. "Static Chaos" also expands theories that diagnose narrative's mimetic relationship to human sexual intercourse and sexuality, particularly those of Judith Roof and Lee Edelman who assert narrative's heterosexuality based on its traditional logic of continuation. I argue that post-war formal experimentation in modernist literature renders narrative metaphorically sterile by disrupting reproductive traditions and conventions. These formal components include generic manipulation, representations of inversion and paradox, ambiguous or inconclusive endings, and parodic or circular plot structures. Together with themes of sterility, these formal elements work to depict the post-war world as fixed in a barren wasteland, trapped in static chaos.
24

Molecular analysis of polima cytoplasmic male sterility in Brassica napus

Singh, Mahipal January 1992 (has links)
No description available.
25

Fine mapping of the nuclear restorer locus for cytoplasmic male sterility in Brassica napus

Stollar, Rachel. January 2001 (has links)
No description available.
26

Expression of a Brassica napus mitochondrial gene region associated with cytoplasmic male sterility : transcript initiation, editing, splicing and nuclease processing

Elina, Helen. January 2007 (has links)
Cytoplasmic male sterility (CMS) is a maternally inherited trait of higher plants that can be suppressed by nuclear restorers of fertility ( Rf) genes that normally down-regulate the expression of a CMS-associated mitochondrial gene. In Brassica napus, nap CMS is associated with the expression of the orf222/nad5c/orf2101 mitochondrial gene region and is suppressed by the restorer gene Rfn. I present here an extensive analysis of the expression of the orf222/nad5c/orf2101 region in nap CMS and fertility-restored plants. Using RT-PCR methodology, I mapped transcript initiation sites, processing sites, and 3' termini. I identified two processing events, one within and one immediately downstream of orf222, that are specific to fertility restored plants and I suggest possible mechanisms by which the Rfn protein may recognize cognate RNA substrates. Unexpectedly, I also found that levels of atp8 transcripts are much lower in CMS than in restored plants. / nad5c, one of the components of the nap CMS-associated region, is the small central exon of the nad5 gene. In higher plants, nad5c transcripts must be joined to exons b and d through two group II intron trans-splicing events. I found that in the dicot Brassica and the monocot wheat, proper splicing requires exon c and d joining occur prior to the splicing of c with b. Joining of c to a/b transcripts prior to c/d splicing results exclusively in mis-spliced products in which the 5' end of c is joined to cryptic sites within exon b. It is suggested that intron sequences downstream of c base-pair with exon a, leading to mis-folding of the b/c intron and mis-splicing. In Oenothera, where the c/d intron is further fragmented into a tri-partite intron, mis-splicing does not occur. I suggest that avoidance of mis-splicing may be a factor that drives fragmentation of trans -splicing group II introns and may have contributed to the eventual evolution of spliceosomal RNAs from a group II intron precursor.
27

Fine mapping of the nuclear restorer locus for cytoplasmic male sterility in Brassica napus

Stollar, Rachel. January 2001 (has links)
This thesis will discuss the 'Polima' cytoplasmic male sterility (CMS) system (pol) in Brassica napus (Canola) and detailed genetic mapping of the region surrounding restorer gene ( Rfp) for that system This fine mapping of the Rfp region will facilitate efforts to clone the gene that will eventually lead to its characterization. Knowledge of the structure of Rfp will provide insight in the molecular mechanisms governing mitochondrial gene statement as well as pollen production and may lead to the development of alternative methods of pollination control. In addition, it is possible that nuclear restorer genes for other CMS systems in other crops may be similar to that of the 'Polima' system. / Map based cloning requires the identification of DNA markers tightly linked to Rfp. Two PCR based markers which are located on either side of Rfp were developed. These markers allowed facile screening of a large population. / RFLP markers used in this study are based on the synteny between B. napus and the well known crucifer A. thaliana. (Abstract shortened by UMI.)
28

Molecular analysis of polima cytoplasmic male sterility in Brassica napus

Singh, Mahipal January 1992 (has links)
To identify region(s) of the mitochondrial genome that might be involved in specifying the "Polima" (pol) cytoplasmic male sterility (CMS) of Brassica napus, transcripts corresponding to 14 mitochondrial genes and DNA clones representing $>$90% of the mitochondrial genome of Brassica campestris were analyzed in nap (male fertile), pol (male sterile) and nuclear fertility-restored pol cytoplasm plants. CMS-correlated transcriptional differences among these plants were detected only with the ATPase subunit 6 (atp6) gene. Sequence analysis of the atp6 gene regions of pol and nap mitochondrial DNAs show that rearrangements in the pol mitochondrial genome upstream of atp6 have generated a chimeric 224-codon open reading frame, designated orfJ224, that is cotranscribed with atp6. In male sterile plants, most transcripts of this region are dicistronic, comprising both orf224 and atp6 sequences. In fertility restored-plants, genes at either of two distinct nuclear restorer loci specifically alter this transcript pattern, resulting in predominantly monocistronic atp6 transcripts. The effect of the restorer locus on orf224/atp6 transcripts does not seem to be tissue or developmental stage specific. orf224 comprises a portion of the mitochondrial gene, orfB, fused to sequence of unknown origin. The pol mitochondrial genome contains an apparently functional copy of orfB. The expression of the atp6 region is developmentally regulated in pol plants such that levels of monocistronic atp6 transcripts are increased in seedlings as compared to the floral tissue. Preliminary data indicate that the chimeric gene, orf224, is expressed at the protein level in pol plants.
29

Expression of a Brassica napus mitochondrial gene region associated with cytoplasmic male sterility : transcript initiation, editing, splicing and nuclease processing

Elina, Helen. January 2007 (has links)
No description available.
30

Cytological Characterization of Hybrid Male Sterility Among Sibling Species of the Drosophila Melanogaster Complex / Characterization of Hybrid Male Sterility in Drosophila

Kulathinal, Robie 08 1900 (has links)
Thesis / Master of Science (MS)

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