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971.
972.
Summary The recombinagenic pathway of DNA repair in yeast was characterized by the effect of different inhibitors on the temperature-dependent survival after-irradiation in haploid cells of the thermoconditional mutantrad54-3. Blocking protein synthesis with cycloheximide in replicating cells caused partial inhibiton of theRAD54 dependent function but some repair activity remained detectable. This indicates that-rays can induceRAD54 activity above some constitutive level of function. Inhibition of DNA replication by hydroxyurea efficiently blocked theRAD54 dependent function in stationary-phase cells but not in logarithmic-phase cells. In logarithmic-phase cells, we found a strong inhibitory effect of caffeine on theRAD54 mediated repair process. 相似文献
973.
Gordon Cannon Sabine Heinhorst Janusz Siedlecki Arthur Weissbach 《Plant cell reports》1985,4(2):41-45
A simple method using molecular hybridization was devised to quantitatively measure chloroplast DNA synthesis in vivo. Total cellular DNA isolated from Nicotiana tabacum suspension cells, labeled with 3H-thymidine, was hybridized to nitrocellulose membrane-bound cloned chloroplast DNA (ct DNA) fragments. Colorless, dark grown N. tabacum cells were found to contain approximately 3300–4800 chloroplast genome copies per cell, whereas light grown, green cells contain about 9500–12000 chloroplast genomes per cell. This difference in ct DNA levels suggests that the chloroplast genome is somewhat amplified during growth of the cells in the light. The hybridization technique was also used to measure the efficiency of hybridization between cloned spinach ct DNA and tobacco ct DNA. The two DNAs were found to cross-hybridize with an efficiency of 69–75%. 相似文献
974.
Joseph A. Rothwell Francisco Madrid-Gambin Mar Garcia-Aloy Cristina Andres-Lacueva Caomhan Logue Alison M. Gallagher Carina Mack Sabine E. Kulling Qian Gao Giulia Praticò Lars O. Dragsted Augustin Scalbert 《Genes & nutrition》2018,13(1):15
Non-alcoholic beverages are important sources of nutrients and bioactive compounds that may influence human health and increase or decrease the risk of chronic diseases. A wide variety of beverage constituents are absorbed in the gut, found in the systemic circulation and excreted in urine. They may be used as compliance markers in intervention studies or as biomarkers of intake to improve measurements of beverage consumption in cohort studies and reveal new associations with disease outcomes that may have been overlooked when using dietary questionnaires. Here, biomarkers of intake of some major non-alcoholic beverages—coffee, tea, sugar-sweetened beverages, and low-calorie-sweetened beverages—are reviewed. Results from dietary intervention studies and observational studies are reviewed and analyzed, and respective strengths and weaknesses of the various identified biomarkers discussed. A variety of compounds derived from phenolic acids, alkaloids, and terpenes were shown to be associated with coffee intake and trigonelline and cyclo(isoleucylprolyl) showed a particularly high specificity for coffee intake. Epigallocatechin and 4′-O-methylepigallocatechin appear to be the most sensitive and specific biomarkers for green or black tea, while 4-O-methylgallic acid may be used to assess black tea consumption. Intake of sugar-sweetened beverages has been assessed through the measurement of carbon-13 enrichment of whole blood or of blood alanine in North America where sugar from sugarcane or corn is used as a main ingredient. The most useful biomarkers for low-calorie-sweetened beverages are the low-calorie sweeteners themselves. Further studies are needed to validate these biomarkers in larger and independent populations and to further evaluate their specificity, reproducibility over time, and fields of application. 相似文献
975.
Katja Osterloh Nadine Tauchnitz Oliver Spott Johannes Hepp Sabine Bernsdorf Ralph Meissner 《Wetlands Ecology and Management》2018,26(1):87-102
During the last decades, various renaturation programmes have been initialized to recover nutrient sink and ecological functions of peatlands by rewetting. Rewetting, however, often results in the formation of hotspots for methane (CH4) emissions and in temporal dieback of local vegetation. The present study aimed at quantifying changes of CH4 and nitrous oxide (N2O) emissions in a peatland currently under continuous rewetting conditions. Emissions where studied at a permanently flooded site and a non-flooded peat site with fluctuating water tables by using common closed chamber method. The permanently flooded site revealed extremely high CH4 emissions (up to 1195 mg C m?2 d?1) which were positively correlated with temperature, nutrient content, dissolved organic carbon and nitrogen concentration of the peat soil water. In contrast, the non-flooded peat site, with lower and fluctuating water tables (WT), showed significantly lower CH4 emissions and an increasing trend of CH4 release associated with a generally increasing WT caused by the progressing rewetting process. Lower N2O emissions (<24 µg N m?2 d?1) were observed at the flooded site. By contrast, the non-flooded peat site with fluctuating WT showed significantly higher N2O emissions (up to 4178 µg N m?2 d?1), in particular at high temperatures during summer time. The present results indicate that permanently flooded conditions during rewetting processes might cause higher CH4 emissions compared to fluctuating WT which in contrast might enhance N2O emissions. In total, however, no decreasing trend for CH4 emissions throughout the five-year renaturation period could be found. At least for N2O we observed a decreasing trend during rewetting. 相似文献
976.
Selenium Utilization by GPX4 Is Required to Prevent Hydroperoxide-Induced Ferroptosis 总被引:1,自引:0,他引:1
Irina Ingold Carsten Berndt Sabine Schmitt Sebastian Doll Gereon Poschmann Katalin Buday Antonella Roveri Xiaoxiao Peng Florencio Porto Freitas Tobias Seibt Lisa Mehr Michaela Aichler Axel Walch Daniel Lamp Martin Jastroch Sayuri Miyamoto Wolfgang Wurst Fulvio Ursini Marcus Conrad 《Cell》2018,172(3):409-422.e21
977.
Redescription of Tintinnopsis everta Kofoid and Campbell 1929 (Alveolata,Ciliophora, Tintinnina) Based on Taxonomic and Genetic Analyses—Discovery of a New Complex Ciliary Pattern
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978.
Roland Loppes Nathalie Devos Sabine Willem Pascal Barthlemy Ren F. Matagne 《Journal of phycology》1996,32(2):276-278
A psychrophilic green alga belonging to the Chloromonas genus and here named ANT1 was collected in Antarctica. The activities of two enzymes, nitrate reductase and argininosuccinate lyase, were measured at various temperatures and compared to the corresponding enzyme activities in the mesophilic species Chlamydomonas reinhardtii Dangeard. For both enzymes, the temperature for apparent optimal activity was about 20°C lower in ANT1 than in C. reinhardtii. The enzymes were also submitted to various heat treatments before measuring their activities. Both psychrophilic enzymes were more sensitive to heat than the corresponding mesophilic enzymes. It is worth stressing, however, that in both species nitrate reductase was much more sensitive to heat than argininosuccinate lyase, which probably indicates that the peculiar structure of each protein primarily determines its dependence to temperature. Secondary adaptations to low temperatures should then occur to confer the psychrophilic character. 相似文献
979.
John W. Corum III Andrew J. Hartung Robin T. Stamey Sabine J. Rundle 《Plant molecular biology》1996,31(2):419-427
We have indentified a novel gene (AtB) encoding a previously uncharacterized isoform of the B regulatory subunit of the type 2A serine/threonine protein phosphatase (PP2A) of Arabidopsis, and show that mRNA derived from the AtB gene accumulates in all Arabidopsis organs. In addition, we examined the expression of the three genes encoding the A regulatory subunit of Arabidopsis PP2A and show these genes are expressed in all organs as well. Taken together, our results suggest a myriad of PP2A subunit combinations, possibly with distinct substrate specificities, may occur within each Arabidopsis cell. 相似文献
980.
Hélène Barbier-Brygoo Sabine Zimmermann Sébastien Thomine Ian R. White Paul Millner Jean Guern 《Plant Growth Regulation》1996,18(1-2):23-28
Studies of membrane electrical responses of isolated protoplasts to auxin have demonstrated the existence of elementary response chains to auxin at the plasma membrane, presently defined only by their uttermost ends. At one side, as demonstrated by several lines of evidence, the auxin perception unit involves proteins homologous to ZmER-abp1 (abp1), the most abundant auxin-binding protein from maize coleoptiles. At the other side, multiple ion transport proteins appear as targets of the auxin signal; the proton pump ATPase, an anion channel and potassium channels. We investigated early electrical responses to auxin at the plasma membrane of tobacco protoplasts. The work presented here will initially focus on abp1 and its functional role at the membrane. The C-terminus abp1 peptide (Pz151–163) was recently reported to modulate K+ currents at the plasma membrane of intact guard cells from broad bean [23] and induce plasma membrane hyperpolarisation of tobacco mesophyll protoplasts. These results further demonstrate that proteins involved in plasma membrane responses to auxin are related to maize abp1, and provide clues as to the region of the protein possibly involved in the interaction of abp1 with the plasma membrane. Secondly, this report concentrates on one of the targets of auxin, a voltage-dependent and ATP-regulated anion channel that we characterised on protoplasts from tobacco cell suspensions. This anion channel was specifically modulated by auxin, as already observed for the anion channel of guard cells [14]. Further work will be needed to assess if this auxin modulation involves a direct interaction between the hormone and the anion channel protein(s), or follows from the activation of a perception chain including abp1 homologues. 相似文献