Some 7,500 seeds of Lotus corniculatus cv. Mirabel were treated with X-rays (3,000-12,000 Rads), ethyl methanesulfonate, 8-ethoxycaffeine, n-hydroxyurea, and 2-aminopurine (0.001 to 1.0% solutions). A total of 93 selfed, partially inbred, and open-pollinated lines, comprising some 22,000 plants, were generated over four generations. Mutagenic effects were assessed on germination, seedling survival, meiotic aberrations, pollen abortion, seed and forage yields, pod dehiscence, winter hardiness, brown floral keel tip color, and cyanoglycoside (HCA) content in the leaves. Dose effects were largely confined to the M(,1) generation. Germination and seedling survival could not be used to predict mutation rates. Higher levels of forage and seed yields and lower levels of HCA content were induced. Pod dehiscence, winter hardiness and brown keel tip frequency were not affected. Three qualitative mutants, chlorotica, vestigial floret, and dwarf, were tetrasomic recessives. Only tetrasomically inherited characters were found. X-rays and EMS were the most effective mutagens.

No description available.

The secondary structure of the 33 kDa manganese-stabilizing protein from Anacystis nidulans R2 was predicted using information from a family of homologous sequences and applying the algorithms of Williams et al. and Zvelebil et al. From the sequence conservation and the predicted secondary structure, nine functionally important domains were identified. Additional algorithms predicted potential antigenic determinants and a region that may serve to bind this polypeptide to the Photosystem II core complex. One of the functionally significant regions exhibits partial sequence similarity to the Mn-binding site of the bacterial superoxide dismutase and was targeted for site-directed mutagenesis. Two aspartic acid residues in this region, which may form carboxyl bridges to stabilize Mn ions, were subjected to saturation mutagenesis. A hybrid vector which affords temperature regulated expression of a cloned gene, was constructed to introduce the various forms of the mutated gene into the cyanobacterium, A. nidulans R2. Pools of Eschericia coli and A. nidulans cells harboring mutant polypeptides have been obtained. Some mutant cyanobacteria display altered pigmentation and differences in generation time dependent upon growth temperature suggesting a functionally significant residue has indeed been altered. Future studies will be concerned with the characterization of specific mutants in order to determine the relationship between the structure and function of this polypeptide. / Department of Biology

Although a central etiology for Alzheimer disease (AD) has not yet been determined, support has amassed for the notion that oxidative stress may be involved in the pathogenesis of AD. The disruption of iron homeostasis and iron's excessive deposition in AD brain tissues has received increased attention due to the metal's capacity to promote the production of harmful free radicals. Several studies have recently examined whether DNA mutations involved in the iron overload disorder, hemochromatosis, pose an increased risk of acquiring AD. However, the small sample size and low generalizability of previous studies have warranted further investigation. We genotyped 213 AD patients, 106 Mild Cognitively Impaired (MCI) individuals, and 63 Normal Elderly Control (NEC) subjects for the H63D and C282Y HFE mutations to examine whether a relationship exists between HFE gene status and AD presentation in our patient population. DNA analysis was conducted by polymerase chain reaction (PCR) followed by restriction fragment length polymorphism (RFLP). We did not find any statistically significant associations between HFE gene status and the clinical, demographic, or neuropsychological aspects of AD in our patient population. Interesting trends that fell short of statistical significance included: (a) a deleterious effect of HFE mutations on motor performance, (b) an influence of H63D homozygosity on an earlier onset of cognitive decline, and (c) an influence of H63D homozygosity on an accelerated progression from MCI to AD.

Thesis (MAppSc)--University of South Australia, 1997

Proefschrift Universiteit van Amsterdam. / Met samenvatting in het Nederlands.

Thesis (Ph. D.)--George Mason University, 2007. / Title from PDF t.p. (viewed Jan. 22, 2008). Thesis director: Iosif I. Vaisman. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Bioinformatics. Vita: p. 140. Includes bibliographical references (p. 133-139). Also available in print.

Diss. (sammanfattning) Umeå : Univ., 2003. / Härtill 5 uppsatser.

Thesis (Ph. D.)--Virginia Commonwealth University, 2008. / Prepared for: Dept. of Microbiology and Immunology Bibliography: leaves 290-312. . Also available online via the Internet.

Thesis (Ph. D.)--Ohio State University, 2003. / Title from first page of PDF file. Document formatted into pages; contains xix, 135 p.; also includes graphics (some col.) Includes bibliographical references (p. 128-135). Available online via OhioLINK's ETD Center