Thesis (Ph. D.)--University of Chicago, Dept. of Molecular Genetics and Cell Biology, 2002. / Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--York University, 1999. Graduate Programme in Biology. / Typescript. Includes bibliographical references (leaves 116-143). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNQ39313.

The nucleotide sequence of the cnjA cDNA (formerly pC1) from the ciliated protozoan Tetrahymena thermophila was determined. This gene was previously found to be conjugation specific and to peak in expression just prior to or at pachytene in meiotic prophase I. The cnjA message is initiated from four transcription start sites, one minor and three major, and encodes a putative protein (CnjA) of 779 amino acids. The protein has a calculated molecular weight of 89.5 kDa and is mainly hydrophilic with an estimated pI of 9.3. CnjA was found to share no sequence similarities with any known protein to date. The gene's coding region demonstrates an unusual codon choice. Flanking regions of the cnjA genomic locus were amplified by means of the Inverse PCR method but attempts at subcloning and characterizing its promoter region were unsuccessful.

Loss of germ cells that entered meiosis at different developmental stages was compared. Mice were injected with BrdU at 13.3, 14.3 or 15.3 days post coitum (dpc) and sacrificed either 3 days after BrdU injection or 4 days post partum (dpp). BrdU-labeled germ cells were detected in ovarian sections through double immunofluorescent staining for BrdU and either GCNA-1 or MVH as a germ cell marker. The results show that the loss of germ cells that entered meiosis at 13.3 or 15.3 dpc was excessive compared to the loss of total germ cells. Such preferential elimination was not found for germ cells that entered meiosis at 14.3 dpc. We conclude that oocyte loss during meiotic prophase is influenced by the timing of meiotic onset. / The mechanism of germ cell loss during ovarian development was tested by the presence of markers for apoptosis. Mouse ovaries were isolated at 12.5 dpc, 18.5 dpc and 2 dpp and cultured with doxorubicin (DXR) to induce cell death. Ovarian histological sections were double immunofluorescent stained for GCNA-1 and cleaved caspase-3 or PARP-1. The results suggest that caspase-3 is not activated in germ cells throughout ovarian development whereas PARP-1 is activated in germ cells at 12.5 dpc and 2 dpp but not at 18.5 dpc. Thus, no evidence has yet been provided to support the hypothesis that oocyte death during the meiotic prophase is mediated by apooptosis.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1937. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 34-38).

Thesis (Ph. D. in Cell and Developmental Biology)--Vanderbilt University, Dec. 2009. / Title from title screen. Includes bibliographical references.

Thesis--Universiteit van Amsterdam. / "Literatuur-overzicht" : p. 80-3.

Thesis (M.Sc.)--York University, 2004. Graduate Programme in Biology. / Typescript. Includes bibliographical references (leaves 48-64). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pMQ99355

Thesis (Ph. D.)--University of Iowa, 2007. / Supervisor: John M Logsdon, Jr. Includes bibliographical references (leaves 213-238).

The study of the genetic control of meiosis has been initiated in Neurospora crassa by the isolation of recessive meiotic mutations. These mutations were detected by their reduced fertility or by the abortion of ascospores. To allow their expression, recessive meiotic mutations were made homozygous by selecting (n + 1) disomic ascospores. Cultures produced by each of these ascospores contain two types of nuclei with identical genes (including mutations) on all chromosomes except linkage group (LG) I, which contains the mating type locus. The simultaneous presence of these two types of nuclei allows the initiation of the sexual cycle, and therefore the detection of recessive mutations affecting the sexual cycle, including meiosis, on any chromosome except LG I. Using this method, three major classes of mutants have been detected. First, eleven mutants affecting perithecial development were expressed only as the maternal parent. Second, thirteen mutants produced perithecia with few or no ascospores. The infertility in two of these mutants was definitely caused by recessive mutations (asc-2 and asc-4). Finally, the abortion of many ascospores was detected in thirteen mutant strains. Among these strains, six recessive mutations (asc-1, asc-3, asc-5, asc-6, asc-7, and asc-8) caused the abortion of many ascospores. The dominant mutation SK(ad-3A) was detected in this screen for recessive mutations, because it caused ascospore abortion when crossed with an ad-3A mutant but not with a wild type strain. This mutation, apparently allelic to ad-3A, caused the abortion of all ad-3A-containing ascospores. The three ascospore abortion-type mutants asc-1, asc-3, and asc-6 were analyzed in more detail using both cytological and genetic methods. Ascospore abortion in these mutants was caused by abnormal disjunction of meiotic chromosomes. In mutants asc-1 and asc-6, the primary defect in pairing of homologs during the first meiotic prophase was followed by the formation of univalents at metaphase I. Observations on these mutants and on the mei-1 mutant (previously isolated; see Smith, 1975) suggested equational centromere division of many univalents at anaphase I. Subsequent irregular and prolonged separation of chromosomes at the second meiotic division appeared to be a secondary effect of the abnormal first division. The asc-3 mutant had a defect in ascus formation, and later in disjunction during the second meiotic and post-meiotic divisions. The first-acting defect before or during karyogamy resulted in the abortion of most cells. Some cells managed to proceed past this block. During the second meiotic division most chromosomes of the few resulting asci were attached to only one of the two spindle-pole bodies. Disjunction at the post-meiotic division was also highly irregular. This mutant appeared to be defective in the attachment of one spindle-pole body to a set of centromeres. The defect may involve either a centromere-associated product or a spindle-pole body. / Science, Faculty of / Botany, Department of / Graduate