The Experts below are selected from a list of 72 Experts worldwide ranked by ideXlab platform
Breck Byers - One of the best experts on this subject based on the ideXlab platform.
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Stage-specific effects of X-Irradiation on yeast meiosis.
Genetics, 1993Co-Authors: Leigh W. Thorne, Breck ByersAbstract:Previous work has shown that cdc13 causes meiotic arrest of Saccharomyces cerevisiae following DNA replication by a RAD9-dependent mechanism. In the present work, we have further investigated the implicit effects of chromosomal lesions on progression through meiosis by eXposing yeast cells to X-Irradiation at various times during sporulation. We find that eXposure of RAD9 cells to X-Irradiation early in meiosis prevents sporulation, arresting the cells at a stage prior to premeiotic DNA replication. rad9 meiotic cells are much less responsive to X-Irradiation damage, completing sporulation after treatment with doses sufficient to cause arrest of RAD9 strains. These findings thereby reveal a RAD9-dependent checkpoint function in meiosis that is distinct from the G2 arrest previously shown to result from cdc13 dysfunction. Analysis of the spores that continued to be produced by either RAD9 or rad9 cultures that were X-irradiated in later stages of sporulation revealed most spores to be viable, even after eXposure to radiation doses sufficient to kill most vegetative cells. This finding demonstrates that the lesions induced by X-Irradiation at later times fail to trigger the checkpoint function revealed by cdc13 arrest and suggests that the lesions may be subject to repair by serving as intermediates in the recombination process. Strains mutant for chromosomal synapsis and recombination, and therefore defective in meiotic disjunction, were tested for evidence that X-ray-induced lesions might alleviate inviability by promoting recombination. Enhancement of spore viability when spo11 (but not hop 1) diploids were X-irradiated during meiosis indicates that induced lesions may partially substitute for SPO11-dependent functions that are required for the initiation of recombination.
Peter J.c. Van Breda Vriesman - One of the best experts on this subject based on the ideXlab platform.
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X-Irradiation of the thymus is not required for the induction of cyclosporine-induced autoimmunity.
Transplantation, 1995Co-Authors: Leo J.j. Beijleveld, Jan Damoiseaux, K. Willem H. Wodzig, Peter J.c. Van Breda VriesmanAbstract:The thymus-dependent model of cyclosporine-induced autoimmunity (CsA-AI) in the Lewis rat requires a lethal total body X-Irradiation and rescue with syngeneic or autologous bone marrow and cyclosporine (CsA) administration for at least 4 weeks; two to three weeks after cessation of CsA, the animals develop a graft-versus-host-like disease. The obligatory role of the thymus in the etiology of CsA-AI has been established unequivocally, but the way in which disease is thymus dependent is a topic of debate. In the present study we demonstrate that the model of CsA-AI requires the presence of a thymus for at least 2 weeks after total body Irradiation and CsA administration, but that X-Irradiation of the thymus itself is not necessary to bring about disease. Transplantation of neonatal thymus shows in addition that in the absence of X-Irradiation of the thymus, CsA therapy is required to generate autoreactive cells, but that disease occurs only if peripheral autoregulatory cells are eliminated by X-Irradiation.
Hajime Fuchihata - One of the best experts on this subject based on the ideXlab platform.
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Effect of X Irradiation on Secondary Palate Development in Mice
Radiation Research, 2000Co-Authors: Hiroko Hiranuma, Akitoshi Jikko, Takashi Maeda, M. Abe, Hajime FuchihataAbstract:Abstract Hiranuma, H., Jikko, A., Maeda, T., Abe, M. and Fuchihata, H. Effect of X Irradiation on Secondary Palate Development in Mice. The mechanisms whereby X Irradiation induces palatal clefting were investigated in vivo and in an in vitro organ culture system. When pregnant mice at day 12.5 of gestation were eXposed to a 4-Gy dose of whole-body X radiation, the incidence of palatal clefting in their offspring was 91%. The volume of the irradiated palatal shelves was too low for them to make contact with each other. On gestational day 13.5 after labeling, bromodeoXyuridine-positive cells were sparse and apoptotic cells were abundant in the irradiated shelves. To prevent secondary effects of Irradiation from the injured maternal body, fetal palatal eXplants were immediately transferred to an organ culture system after X Irradiation in utero. The incidence of palatal clefting was 24%, much lower than the incidence in vivo. The addition of 10–4 M of deXamethasone to the culture medium increased the incide...
William J Anderson - One of the best experts on this subject based on the ideXlab platform.
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noradrenergic innervation of the eXternal granular layer of the rat following low level X Irradiation
Developmental Neuroscience, 1994Co-Authors: Phillip Edward Kunkler, William J AndersonAbstract:The distribution of the noradrenergic system within the rat cerebellar corteX following low-level X-Irradiation was studied using tyrosine hydroXylase immunocytochemistry. X-Irradiation treatments con
Leigh W. Thorne - One of the best experts on this subject based on the ideXlab platform.
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Stage-specific effects of X-Irradiation on yeast meiosis.
Genetics, 1993Co-Authors: Leigh W. Thorne, Breck ByersAbstract:Previous work has shown that cdc13 causes meiotic arrest of Saccharomyces cerevisiae following DNA replication by a RAD9-dependent mechanism. In the present work, we have further investigated the implicit effects of chromosomal lesions on progression through meiosis by eXposing yeast cells to X-Irradiation at various times during sporulation. We find that eXposure of RAD9 cells to X-Irradiation early in meiosis prevents sporulation, arresting the cells at a stage prior to premeiotic DNA replication. rad9 meiotic cells are much less responsive to X-Irradiation damage, completing sporulation after treatment with doses sufficient to cause arrest of RAD9 strains. These findings thereby reveal a RAD9-dependent checkpoint function in meiosis that is distinct from the G2 arrest previously shown to result from cdc13 dysfunction. Analysis of the spores that continued to be produced by either RAD9 or rad9 cultures that were X-irradiated in later stages of sporulation revealed most spores to be viable, even after eXposure to radiation doses sufficient to kill most vegetative cells. This finding demonstrates that the lesions induced by X-Irradiation at later times fail to trigger the checkpoint function revealed by cdc13 arrest and suggests that the lesions may be subject to repair by serving as intermediates in the recombination process. Strains mutant for chromosomal synapsis and recombination, and therefore defective in meiotic disjunction, were tested for evidence that X-ray-induced lesions might alleviate inviability by promoting recombination. Enhancement of spore viability when spo11 (but not hop 1) diploids were X-irradiated during meiosis indicates that induced lesions may partially substitute for SPO11-dependent functions that are required for the initiation of recombination.
