Mutations in the melanocortin 2 receptor (MC2R) and its accessory protein (MRAP), in the ACTH signalling pathway, and the antioxidant genes nicotinamide nucleotide transhydrogenase (NNT) and thioredoxin reductase 2 (TXNRD2) have been associated with familial glucocorticoid deficiency (FGD). Using a tandem affinity purification and mass spectrometry approach to identify interacting partners of MC2R and MRAP failed to identify putative candidate genes for further FGD cases. However in a male patient a homozygous mutation in another antioxidant gene, glutathione peroxidase 1 (GPX1), was identified. In vitro studies showed H295R cells with knockdown of GPX1 had 50% less basal GPX activity and were less viable than wild-type when exposed to oxidative stress. Adrenals from Gpx1-/- mice showed no gross morphological changes and corticosterone levels were not significantly different from their wild-type counterparts (in contrast to the Nnt mutants). Sequencing of >100 FGD patients did not reveal any other GPX1 mutations. This equivocal data lead to the hypothesis that there could be a second gene defect present in this proband contributing to his disease. Whole exome sequencing revealed a homozygous loss-of-function mutation in peroxiredoxin 3 PRDX3 (p.Q67X) in this patient, that was also present in his unaffected brother. In vitro studies revealed both single and double knockdown of the two genes in H295R cells reduced cell viability, but redox homeostasis and cortisol production were unaffected. GPXs and PRDXs work simultaneously to reduce H2O2, preventing cellular damage. My data suggest that loss of PRDX3 alone is insufficient to cause adrenal failure and further that mutation in GPX1, either alone or in combination with PRDX3 mutation, may tip the redox balance to cause FGD.

The response of field corn to iron and zinc fertilization was studied using a split plot experimental design in Millard County, Utah, in cooperation with the Utah Stat e University Extension Agent and a local farmer. ~!ainp l ot treatment applications consisted, on an acre basis, of (1) 5 t ons of sulfuric acid, (2) 1 ton sulfuric acid, (3) 1.8 tons gypsum, (4) check plot. Subplot treatments were (1) Fe at 5 lbs/Ac, (2) Zn at 10 lbs/Ac, (3) Fe and Zn at 5 and 10 lb / Ac, respectively, (4) check plot . The iron and zinc applications were essentially rendered unavailable by reactions of the applied iron and zinc with the highly calcareous soil matrix. Experimental variability and the relatively low rates of applied micronutrients combined to produce insignificant yield responses to micronutrient fertilization. Another study was conducted to predict the soil iron critical level. Five soils from Millard County, representing some of the soils low in iron and zinc,were selected for a greenhouse study. All five of the soils were equal l y divided into three groups and assigned one of three pretreatments. One- third of the soils were stressed by successive croppings with corn and oats. One-third of the soils were fertilized with Fe chelate and znso 4 at 5 ppm each as a pretreatment. And one-third of the soils did not receive a pretreatment. The pretreatments were designed to obtain a broader range of soil iron concentrations. After the pre treatments were completed on all of the soils, a randomized block experimental design was employed to measure potential yield increases in corn produced by the addition of Fe chelate . Two corn genotypes, an iron-efficient corn inbred (WF9) and an iron efficient corn mutant (Ysl/Ysl), were utilized in the gr eenhouse study. The treatments were (1) 5 ppm Fe chelate plus corn inbred WF9, (2) 5 ppm Fe chelate plus corn mutant Ysl/Ysl, (3) no Fe addition plus corn inbred WF9 , (4) no Fe addition plus corn mutant Ysl/Ysl. Significant yield responses to Fe fertilization were determined by an LSD statistical test . Generally, soils with a DTPA extractable iron level greater than 5 ppm did not respond to applied iron. Similar yield responses were obtained for the iron-efficient and ironinefficient varieties. A tentative critical level of DTPA extractable iron of 5 ppm was proposed for the calcareous soils of Millard County, Utah.

No description available.

ArsA is the catalytic component of an arsenite extrusion pump in E. coli that confers arsenite and antimonite resistance. YDL100cp is the ArsA homologous protein found in S. cerevisiae. Previous studies show that YDL100c gene is not directly related to arsenical resistance mechanism in S. cerevisiae but the YDL100c disrupted strain (KO) showed sensitivity to Zn2+ at 30oC and more pronounced sensitivity at 37oC. To study the role of YDL100c on Zn2+ sensitivity, wild type strain (WT) and KO were grown at 30oC and 37oC for 6 hr after adding Zn2+. Both strains were assayed for trehalose accumulation, intracellular oxidation level and GSH content. The results demonstrate that KO had a decreased growth and increased intracellular oxidation at 37oC when compared to WT. Addition of Zn2+ did not increase the intracellular oxidation in WT and KO grown at 30oC but to a greater extent in KO compared to WT grown at 37oC. Further assess the function of antioxidant genes shows that there is no significant difference in SOD1 expression between KO and WT grown at 37oC but CTT1 expression is low in KO. There is an increase in catalase activity for both WT and KO by adding Zn2+ at 30oC or 37oC, but the level of catalase activity to KO is still lower than that of WT.In conclusion, a defect of YDL100c results in a defect in the activation of general stress response at 37oC. Consequently, the cause of the increased level of intracellular oxidation of KO in the presence of Zn2+ grown at 37oC is most likely related to the decrease in cellular GSH content and trehalose accumulation in KO compared to that of WT. Therefore, the pronounced sensitivity to Zn2+ at 37oC is mainly due to a defect in general stress response in KO when grown at 37oC.

Thesis (Ph. D.)--University of Florida, 1970. / Description based on print version record. Typescript. Vita. Includes bibliographical references (leaves 103-110).

Thesis (M.S.)--Florida State University, 2003. / Advisor: Dr. Cathy W. Levenson, Florida State University, College of Human Sciences, Dept. of Nutrition, Food, and Exercise Sciences. Title and description from dissertation home page (viewed May 18, 2004). Includes bibliographical references.

Thesis--M.D., University of Hong Kong, 1983.

published_or_final_version / Medicine / Master / Doctor of Medicine

No description available.

Methylenetetrahydrofolate reductase (MTHFR) reduces 5,10-methylene THF to 5-methyl THF, the carbon donor for the methylation of homocysteine to methionine. Patients with severe MTHFR deficiency (MRD) have neurologic abnormalities while a milder form (a thermolabile MTHFR variant) has been shown to be associated with coronary artery disease (CAD). Ten MRD patients, with reduced or non-detectable activity, were studied to characterize the nature of the mutation. Southern, Northern and Western analysis did not reveal any defects in the patients. These results suggest that the mutations may be minor insertions/deletions or single base substitutions that affect catalytic activity. Single strand conformation polymorphism (SSCP) analysis was used to detect base substitutions; 3 RFLPs were identified with this protocol. One was in the coding region (SphI) while the other two were in the 3$ sp prime$ untranslated region (MaeIII and MnlI). A difference in frequency of the SphI RFLP was found between control subjects and a small sample of CAD patients whose homocysteine levels were greater than the 99th percentile.