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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.
1

Maturation in vitro and subsequent fertilization of mammalian follicular oocytes.

Shea, Brian Francis. January 1974 (has links)
No description available.
2

Induction and maintenance of corpora lutea in prepuberal gilts.

Segal, Donald Howard. January 1970 (has links)
No description available.
3

Transport, survival and union of foreign gametes in the genital tract of the rabbit.

Coggins, Ellsworth George. January 1968 (has links)
No description available.
4

Development of rabbit and cattle ova in vitro.

Robertson, James Ernest. January 1969 (has links)
No description available.
5

Induction and maintenance of pregnancy in prepuberal pigs and rats.

Shaw, George Alvin. January 1969 (has links)
No description available.
6

The evaluation of frozen and thawed mammalian embryos and oocytes.

Segal, Neil B. January 1976 (has links)
No description available.
7

A revision of the genus Centella L. (Apiaceae)

Schubert, Mahalia Theresia Reina 02 June 2014 (has links)
D.Phil. (Botany) / A taxonomic revision of the genus Centella is presented that is based on vegetative and reproductive characters. Genetic data was included in the extensive research ofpossible hybridisation. Hybridization as a possible mechanism of evolution may account for the lack of conguence between taxonomic characters in Centella. Phylogenetic and phenetic methods of analysis were used to explore the relationships among species. The results show that Centella is a particularly difficult genus, with many ofthe problems experienced at species level being a reflection ofthe problematic nature of the Apiaceae. The taxonomic treatment includes nomenclature, synonymy, typification, diagnostic characters, detailed illustrations and geographical distribution of all 45 species that are recognized. Keys to the subgenera, sections and species are provided. The revision includes several taxonomic and nomenclatural changes. The genus is subdivided as follows: Subgenus Trisanthus Subgenus Solandra Subgenus Centella 1 species 4 species Section Erianthae Section Tri/obae Section Centella Section Virgatae 9 species 3 species 16 species 12 species The following 13 new species were described: C. annua, C. calcaria, C. rotundifolia, C. umbellata, C. ternata, C. crenata, C. cryptocarpa, C. gymnocarpa, C. pi/osa, C. brachycarpa, C. dolichocarpa, C. thesioides and C. glauca. One ofthese species C. cryptocarpa, has been collected for the first time. Centalla rotundifolia, C. cordata and C. longifolia were elevated to species rank and C. rigescens was reinstated as a species of Centella. The number of varieties was significantly reduced and variation within the species is mostly described informally. Varieties were retained for only two species. New varieties are: C. tridentata var. tridentata, C. tridentata var. littoralis, C. tridentata var. hermanniifolia, C. tridentata var. dregeana, C. graminifolia var. graminifolia, C.graminifolia var. natalensis and C. graminifolia var. stipitata.
8

Effects of zinc and copper on the post ovulatory reproductive potential of the sharptooth catfish, Clarias gariepinus

Viljoen, Alfonso 27 August 2012 (has links)
M.Sc. / Sperm, eggs, free embryos and larvae of the sharptooth catfish, Clarias gariepinus, were used in a series of experiments conducted with zinc and copper salts in a flow-through exposure system. Metal concentrations ranged between 0 to 9mg/1 water. The aim of the study was to determine which of these early life stages was the most sensitive towards these metals and to determine whether the early life stages of the sharptooth catfish could be used for rapid bioassesment studies. Parameters investigated were sperm quality, egg hatchibility, free embryo and larval survival and growth. Within all the parameters tested sperm quality proved to be the least sensitive, with no significant changes noted at the metal concentrations used. There are notable reductions on hatching success embryonic and larval survival and growth as metal concentrations increased. Results revealed that the most sensitive was the free embryo stage directly after, and up to 48 hours after hatching. 48 hour old free embryo displayed 48th L.C.50 values as low as 1.98mg/l for zinc and 0. 0.13mg/l for copper, which indicated that this stage was very sensitive and susceptible to environmental stressors. Since C. gariepinus is an indigeniuos species that is widespread throughout the African continent and considering the sensitivity of the early life stages it is a succesfull candidade for use in rapid bioassessment tests throughout the continent.
9

E7 PROTEINS OF HIGH-RISK (TYPE 16) AND LOW-RISK (TYPE 6) HUMAN PAPILLOMAVIRUSES REGULATE p130 DIFFERENTLY

Barrow, Lisa C. 15 October 2010 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Human papillomaviruses (HPVs) are one of the most common causes of sexually transmitted disease in the world. HPVs are divided into high-risk (HR) or low-risk (LR) types based on their oncogenic potential. HPVs 16 and 18 are considered HR types and can cause cervical cancer. HPVs 6 and 11 are classified as LR and are associated with condyloma acuminata (genital warts). Viral proteins of both HR and LR HPVs must be able to facilitate a replication competent environment. The E7 proteins of LR and HR HPVs are responsible for maintenance of S-phase activity in infected cells. HR E7 proteins target all pRb family members (pRb, p107 and p130) for degradation. LR E7 does not target pRb or p107 for degradation, but does target p130 for degradation. Immunohistochemistry experiments on HPV 6 infected patient biopsies of condyloma acuminata showed that detection of p130 was decreased in the presence of the whole HPV 6 genome. Further, the effect of HR HPV 16 E7 and LR HPV 6 E7 on p130 intracellular localization and half-life was examined. Experiments were performed using human foreskin keratinocytes transduced with HPV 6 E7, HPV 16 E7 or parental vector. Nuclear/cytoplasmic fractionation and immunofluorescence showed that, in contrast to control and HPV 6 E7-expressing cells, a greater amount of p130 was present in the cytoplasm in the viii presence of HPV 16 E7. The half-life of p130, relative to control cells, was decreased in the cytoplasm in the presence of HPV 6 E7 or HPV 16 E7, but only decreased by HPV 6 E7 in the nucleus. Inhibition of proteasomal degradation extended the half-life of p130, regardless of intracellular localization. Experiments were also conducted to detect E7-binding partners. Cyclin C and cullin 5 were identified as proteins capable of binding to both HPV 6 E7 and HPV 16 E7. Preliminary experiments showed that decreasing protein levels of p600, a binding partner of both HPV 6 E7 and HPV 16 E7, by RNA interference might affect p130 stability. Elucidating the mechanisms of p130 degradation may identify potential targets for preventing degradation of p130 and allowing restoration of cell cycle control.
10

Genome-destabilizing and Mutagenic Effects of Break-induced Replication in Saccharomyces cerevisiae

Deem, Angela Kay 19 August 2011 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / DNA suffers constant damage, leading to a variety of lesions that require repair. One of the most devastating lesions is a double-strand break (DSB), which results in physical dissociation of two pieces of a chromosome. Necessarily, cells have evolved a number of DSB repair mechanisms. One mechanism of DSB repair is break-induced replication (BIR), which involves invasion of one side of the broken chromosome into a homologous template, followed by copying of the donor molecule through telomeric sequences. BIR is an important cellular process implicated in the restart of collapsed replication forks, as well as in various chromosomal instabilities. Furthermore, BIR uniquely combines processive replication involving a replication fork with DSB repair. This work employs a system in Saccharomyces cerevisiae to investigate genetic control, physical outcomes, and frameshift mutagenesis associated with BIR initiated by a controlled HO-endonuclease break in a chromosome. Mutations in POL32, which encodes a third, non-essential subunit of polymerase delta (Pol delta), as well as RAD9 and RAD24, which participate in the DNA damage checkpoint response, resulted in a BIR defect characterized by decreased BIR repair and increased loss of the broken chromosome. Also, increased incidence of chromosomal fusions determined to be half-crossover (HCO) molecules was confirmed in pol32 and rad24, as well as a rad9rad50S double mutant. HCO formation was also stimulated by addition of a replication-inhibiting drug, methyl-methane sulfonate (MMS), to cells undergoing BIR repair. Based on these data, it is proposed that interruption of BIR after it has initiated is one mechanism of HCO formation. Addition of a frameshift mutation reporter to this system allowed mutagenesis associated with BIR DNA synthesis to be measured. It is demonstrated that BIR DNA synthesis is intrinsically inaccurate over the entire path of the replication fork, as the rate of frameshift mutagenesis during BIR is up to 2800-fold higher than normal replication. Importantly, this high rate of mutagenesis was observed not only close to the DSB where BIR is less stable, but also far from the DSB where the BIR replication fork is fast and stabilized. Pol  proofreading and mismatch repair (MMR) are confirmed to correct BIR errors. Based on these data, it is proposed that a high level of DNA polymerase errors that is not fully compensated by error-correction mechanisms is largely responsible for mutagenesis during BIR. Pif1p, a helicase that is non-essential for DNA replication, and elevated dNTP levels during BIR also contributed to BIR mutagenesis. Taken together, this work characterizes BIR as an essential repair process that also poses risks to a cell, including genome destabilization and hypermutagenesis.

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