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  • 1
    ISSN: 1432-0983
    Keywords: Key words  Oxidative stress ; Glutathione ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract   Glutathione (GSH) is an abundant cellular thiol which has been implicated in numerous cellular processes and in protection against stress caused by xenobiotics, carcinogens and radiation. Our experiments address the requirement for GSH in yeast, and its role in protection against oxidative stress. Mutants which are unable to synthesis GSH due to a gene disruption in GSH 1, encoding the enzyme for the first step in the biosynthesis of GSH, require exogenous GSH for growth under non-stress conditions. Growth can also be restored with reducing agents containing a sulphydryl group, including dithiothreitol, β-mercaptoethanol and cysteine, indicating that GSH is essential only as a reductant during normal cellular processes. In addition, the GSH 1-disruption strain is sensitive to oxidative stress caused by H2O2 and tert-butyl hydroperoxide. The requirement for GSH in protection against oxidative stress is analogous to that in higher eukaryotes, but unlike the situation in bacteria where it is dispensable for growth during both normal and oxidative stress conditions.
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  • 2
    ISSN: 1432-0983
    Keywords: Key wordsCOX1 ; Intron ; Yeast ; Promoter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Screening of a promoter probe gene bank for DNA sequences that could act as inducible promoters following growth on non-fermentable carbon sources led to the identification of the mitochondrially encoded cytochrome oxidase subunit 1 gene (COX1) as an active sequence. Carbon-source regulation of this promoter was confirmed by a β-galactosidase assay which showed a 31- and 180-fold induction of expression after growth on ethanol or lactate-based media respectively. Two elements matching the CCAAT-binding-factor motif, which is involved in activating transcription on non-fermentable carbon sources, were identified in the putative promoter. Expression was found to be reduced to low levels in otherwise isogenic hap3 and hap4 mutant strains. Thus, this mitochondrial DNA when placed in the nucleus can act as a promoter that is subject to strict carbon-source regulation. These observations are discussed both with respect to the origin of the S. cerevisiae COX1 gene in particular and with respect to the origin of introns in general.
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  • 3
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A procedure for the instrumental neutron activation analysis of Cd in soils with relatively high Cd content and possible inteferences is reported. Cadmium concentrations in Jamaican soils above 4 mg·kg−1 can now be reliably determined by multielemental instrumental activation analysis with an accuracy ±10% and the reasonably high throughput of 30 samples per day. Over 600 geochemical survey samples were analysed for Cd along with some 20 other long-lived elements.
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  • 4
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Many hormones and neurotransmitters evoke Ca2+ release fromintracellular stores, often triggering agonist-specific signatures of intracellular Ca2+ concentration. Inositol trisphosphate (InsP3)1 and cyclic adenosine ...
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  • 5
    ISSN: 1526-100X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: We studied the effects of soil handling operations during bauxite mining and restoration on the numbers and depth distribution of seed stored in the surface soil of the jarrah forest. Germinable seed stores were determined in four sites of undisturbed forest, these same sites after clearing and burning of forest residues, in the soil immediately following the construction of topsoil stockpiles, in the respread topsoil and then after deep ripping of the respread topsoil. Average density of germinable seed at four sites prior to disturbance was 352 m−2. After clearing and burning, the seed store had decreased to a mean 74% of the original forest soil seed store density. When the top-soil was stockpiled prior to respreading, the seed content was further reduced to 31% in freshly constructed stockpiles and had declined to 13% after 10 months in the stockpiles. After ripping of the respread topsoil the seed content was 16% of the original forest seed store density. In one site where the topsoil was directly stripped and respread with no period of stockpiling but with a period of fallow, the seed store was 32% after respreading and then increased to 53% of the original forest store after ripping. This increase may have been caused by an underestimate of the reserves due to insufficient heating of the samples to break dormancy in fire-requiring species. In the forest topsoils seed was concentrated in the upper few centimeters of the soil profile, whereas after the mining and restoration operations seed was evenly distributed throughout the returned soil profile to a depth of 20 cm. Small-seeded annual species, which were common in the forest seed store, were more sensitive to the soil handing operations and declined to very low numbers, whereas hard-seeded plant species such as Acacia spp. were less affected by the soil handling operations. Implications for bauxite mine revegetation operations include the recommendation that direct return of topsoil should be carried out wherever possible with a minimum delay between clearing, stripping, respreading, and ripping.
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  • 6
    ISSN: 1432-1998
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background. Bronchography is occasionally needed for the evaluation and management of some congenital pulmonary anomalies as well as some acquired diseases, usually of the tracheo- bronchial tree. There is currently no effective, approved contrast agent for this imaging tech- nique. Objective. We evaluated five agents (barium sulfate, iohexol, propyliodone oily, propyliodone aqueous, and perflubron) in terms of image quality, histologic changes, and effects on hemodynamics, blood gases, and standard laboratory tests in New Zealand White rabbits. Materials and methods. Animals were anesthetized and intubated. Each contrast agent (0.25 ml/kg) was administered intratracheally. Three animals in each group had intravenous lines placed for blood sampling and blood pressure monitoring and were sacrificed at 1 h. An additional three animals for each agent were sacrificed at 24 h and 1 week after imaging. Blood samples were taken immediately before contrast instillation and at 1 h postbronchography. Fluoroscopic images were recorded on standard VHS video tape and evaluated in blind fashion. Segments of lung tissue and bronchi were obtained for histologic examination. Results. Necrosis and/or inflammatory infiltrates were noted in 78 % of the bronchograms performed with propyliodone aqueous, 67 % with propyliodone oily, 55 % with perflubron, and 33 % with iohexol 120, 240 and 350. No histologic damage was observed with barium. The propyliodones gave the best-quality imaging results and the most histologic changes. Iohexol, in any concentration, gave the least acceptable images and a moderate number of histologic changes. Barium sulfate demonstrated acceptable images with virtually no histologic changes. Conclusion. From the histologic and imaging results, barium is the best available contrast material for bronchography.
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  • 7
    ISSN: 1530-0358
    Keywords: Colitis ; Familial adenomatous polyposis ; Restorative proctocolectomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract PURPOSE: This study was undertaken to identify the optimum level of stapled ileal pouch-anal anastomosis. METHOD: A prospective, randomized trial was completed to compare double-stapled ileoanal anastomosis placed at the top of anal columns (high, n=26) with anastomosis at the dentate line (low, n=21). RESULTS: There was no significant difference in the overall complication rate between operations (high, n=7,vs. low, n=8; P〈0.21). Pouchanal functional score (scale 0–12; 0=excellent, 12=poor) was significantly better in the high anastomosis group (median (range): 2 (1–9) vs. 5.5 (1–12); P〈0.05). Incontinence occurred in only two patients randomized to high anastomosis compared with six in the low anastomosis group. Nocturnal soiling was reported in three patients after high anastomosis and in six patients after dentate line anastomosis. Both operations caused a significant but comparable reduction of maximum anal resting pressure (31 percent after high anastomosis (P〈0.05); 23 percent after low anastomosis (P〈0.05)). However, a significant fall in functional length of the anal canal was only seen after a low pouch-anal anastomosis (P〈0.05). CONCLUSION: Stapled pouch-anal anastomosis at the top of anal columns gives better functional results compared with a stapled anastomosis at the dentate line.
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  • 8
    ISSN: 1573-2983
    Keywords: Atmospheric particulates ; bromine ; Jamaica ; lead
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Medicine
    Notes: Abstract The results of a survey of air particulates at 23 sites across Jamaica for total suspended particulates (TSP), Al, Br, Cl, Na, Pb, and V, by instrumental neutron activation analysis (INAA) and X-ray fluorescence analysis (XRF) are reported. The geometric mean of TSP values, 35 g m-3, is well within the World Health Organisation's standard of 60 g m-3 for TSP, but in areas of high vehicular traffic density the TSP values exceeded this limit. The correlation coefficient between Br and Pb concentrations in the particulates was 0.92 and the Br/Pb ratio of 0.38 compares well with a ratio of 0.39 found in commercial petrol indicating that the exhaust from vehicular traffic is the major source of Pb in atmospheric particulate matter in Jamaica.
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