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Synthesis of radioactive blastmycinRitter, Preston Otto, January 1965 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1965. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. 32-33.
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The chemistry of mold products Synthetic analogs of antimycin. : Metal complexes of antimycin. : Chrysophanic acid and Pachybasin from Aspergillus cyrstallinus.Farley, Thomas M. January 1965 (has links)
Thesis (Ph. D.)--University of Wisconsin, 1965. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.
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Photoaffinity Labeling of the Antimycin Binding Site in Rhodopseudomonas sphaeroidesWilson, Emily 01 May 1984 (has links)
The purpose of this study was to identify the site of interaction of antimycin with the ubiquinone-cytochrome b-c1 oxidoreductase in the photosynthetic bacteria, Rhodopseudomonas sphaeroides. To accomplish this goal, three areas of research were undertaken: the synthesis of a radiolabeled, photoaffinity analog of antimycin, identification of the inhibitory characteristics of this analog, and the photoaffinity labeling of the antimycin binding site. All three areas were accomplished.
The major finding of this study was the identification of an 11,000 dalton polypeptide as the predominantly labeled protein. Although this polypeptide was not exclusively labeled, it was consistently labeled and showed competition with antimycin. These results are consistent with a similar study performed by das Gupta and Rieske (1973) with a mitochondrial preparation.
These results are not conclusive, but do show several interesting points. First, cytochrome b is not the only site of interaction of antimycin with the ubiquinone~cytochrome b-c1 region of the electron transport chain. Secondly, an 11,000 dalton polypeptide is an important component of this protein complex. The function of this polypeptide is unknown, but should provide interesting research for future studies.
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Signal derived from photosynthic electron transport regulates the expression of methionine sulfoxide reductase (Msr) gene in the green macroalga Ulva fasciata DelileHsu, Yuan-ting 20 November 2008 (has links)
This study has investigated the involvement of photosynthetic electron transport chain on the regulation of gene expression of methionine sulfoxide reductase (UfMSR) in the marine macroalga Ulva fasciata Delile.UfMSRA is from copper stress and UfMSRB ir from hypersalinity stress. UfMSRA is similar to Arabidopsis AtMSRA4 and UfMSRB is similar to AtMSRB1. UfMSRA is specific to the MetSO S-enantiomer and UfMSRB catalytically reduces the MetSO R-enantiomer. Both enzymes are required, since in the cell oxidation of Met residues at the sulfur atom results in a racemic mixture of the two stereoisomers. UfMSRA and UfMSRB transcripts were increased by white light, blue light and red light with the maximum at 1 h following a decline, but kept constant in the dark. The magnitude of UfMSRA and UfMSRB transcript increase showed a positive linear correlation to increasing light intensity from 0-1200 u mole¡Pm-2¡Ps-1. The treatment with linear electron transport
chain inhibitors, hydroxylamine, 3-(3,4-dichlorophenyl) -1,1-dimethylurea (DCMU),
2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (DBMIB) and stigmatellin,
effectively inhibited PS II activity under 300 u mole¡Pm-2¡Ps-1 irradiance. DBMIB and
stigmatellin can increase UfMSRA transcript that was reversed by
2,6-dichlorophenolindophenol (DCPIP), a PS I electron donor. It indicates that the
block of electron transport of the downstream of cytochrome b6f indeuces UfMSRA
gene expression. Hydroxylamine, DCMU and DBMIB decreased UfMSRB transcript
that was not reversed by DCPIP while stigmatellin increased UfMSRB mRNA level,
reflecting a role of reduced state with Qo site located at cytochrome b6f on the
induction of UfMSRB gene expression. The cyclic electron transport chain inhibitors,
antimycin A that inhibited photosynthetic electron transport, can inhibit the increase
of UfMSRA and UfMSRB transcripts by irradiance. UfMSRA and UfMSRB gene
expression were both modulated by cyclic electron transport chain and linear electron
transport chain. These results reveal that photosynthetic electron transport chain
modulates UfMSRA and UfMSRB gene expression by change its redox state.
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Pulsatile insulin release from single islets of LangerhansWesterlund, Johanna January 2000 (has links)
<p>Insulin release from single islets of Langerhans is pulsatile. The secretory activities of the islets in the pancreas are coordinated resulting in plasma insulin oscillations. Nutrients amplitude-regulate the insulin pulses without influencing their frequency. Diabetic patients show an abnormal plasma insulin pattern, but the cause of the disturbance remains to be elucidated. Ithe present thesis the influence of the cytoplasmic calcium concentratio([Ca<sup>2+</sup>]<sub>i</sub>) and cell metabolism on pulsatile insulin release was examined in single islets of Langerhans from <i>ob/ob</i>-mice. Glucose stimulation of insulin release involves closure of ATP-sensitive K<sup>+</sup> channels (K<sub>ATP</sub> channels), depolarization, and Ca<sup>2+</sup> influx in β-cells. In the presence of 11 mM glucose, pulsatile insulin secretion occurs in synchrony with oscillations i[Ca<sup>2+</sup>]<sub>i</sub>. When [Ca<sup>2+</sup>]<sub>i</sub> is low and stable, e.g. under basal conditions, low amplitude insulin pulses are still observed. When [Ca<sup>2+</sup>]<sub>i</sub> is elevated and non-oscillating, e.g. when the β-cells are depolarized by potassium, high amplitude insulin pulses are observed. The frequency of the insulin pulses under these conditions is similar to that observed when [Ca<sup>2+</sup>]<sub>i</sub> oscillations are present. By permanently opening or closing the K<sub>ATP</sub> channels with diazoxide or tolbutamide, respectively, it was investigated if glucose can modulate pulsatile insulin secretion when it does not influence the channel activity. Under these conditions, [Ca<sup>2+</sup>]<sub>i</sub> remained stable whereas the amplitude of the insulin pulses increased with sugar stimulation without change in the frequency. Metabolic inhibition blunted but did not prevent the insulin pulses. The results indicate that oscillations in metabolism can generate pulsatile insulin release when [Ca<sup>2+</sup>]<sub>i</sub> is stable. However, under physiological conditions, pulsatile secretion is driven by oscillations in metabolism and [Ca<sup>2+</sup>]<sub>i</sub>, acting in synergy.</p>
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Pulsatile insulin release from single islets of LangerhansWesterlund, Johanna January 2000 (has links)
Insulin release from single islets of Langerhans is pulsatile. The secretory activities of the islets in the pancreas are coordinated resulting in plasma insulin oscillations. Nutrients amplitude-regulate the insulin pulses without influencing their frequency. Diabetic patients show an abnormal plasma insulin pattern, but the cause of the disturbance remains to be elucidated. Ithe present thesis the influence of the cytoplasmic calcium concentratio([Ca2+]i) and cell metabolism on pulsatile insulin release was examined in single islets of Langerhans from ob/ob-mice. Glucose stimulation of insulin release involves closure of ATP-sensitive K+ channels (KATP channels), depolarization, and Ca2+ influx in β-cells. In the presence of 11 mM glucose, pulsatile insulin secretion occurs in synchrony with oscillations i[Ca2+]i. When [Ca2+]i is low and stable, e.g. under basal conditions, low amplitude insulin pulses are still observed. When [Ca2+]i is elevated and non-oscillating, e.g. when the β-cells are depolarized by potassium, high amplitude insulin pulses are observed. The frequency of the insulin pulses under these conditions is similar to that observed when [Ca2+]i oscillations are present. By permanently opening or closing the KATP channels with diazoxide or tolbutamide, respectively, it was investigated if glucose can modulate pulsatile insulin secretion when it does not influence the channel activity. Under these conditions, [Ca2+]i remained stable whereas the amplitude of the insulin pulses increased with sugar stimulation without change in the frequency. Metabolic inhibition blunted but did not prevent the insulin pulses. The results indicate that oscillations in metabolism can generate pulsatile insulin release when [Ca2+]i is stable. However, under physiological conditions, pulsatile secretion is driven by oscillations in metabolism and [Ca2+]i, acting in synergy.
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