PubMed · 4557893
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F Ruzicka. 1972. [A rapid blood-cell embedding technic for the electron microscope].. https://doi.org/10.1007/bf01631988
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Yeasts are beneficial microorganisms for human society and are utilized for academic and industrial purposes. For academic purposes, S. cerevisiae is a well-investigated model for studying eukaryotic cellular processes. For industrial purposes, S. pastorianus, which has a hybrid genome of S. cerevisiae and S. eubayanus, has been served for lager beer production. During fermentation, S. pastorianus produces ~7% of EtOH, which induces plasma membrane (PM)/cell wall stress in yeast. Therefore, S. pastorianus may experience PM stress and adapt to the self-forming environment during fermentation. However, how yeast adapts to PM stress remains unclear. Here, we investigated the temporal cellular responses of S. cerevisiae and S. pastorianus during adaptation to PM stresses by time-resolved mRNA-seq analysis. Our data showed different transcriptional phenotypes between S. cerevisiae and S. pastorianus during adaptation. The results may reflect the distinct nature of the two yeasts that have evolved in different nutritional environments. The dataset presented here would provide a promising resource for studying the characteristic nature of these differentially domesticated yeasts upon PM stresses.
The present work set out to define the processes involved in the early O3-induced H2O2 accumulation in sunflower plants exposed to a single pulse of 150 ppb of O3 for 4 h. Hydrogen peroxide accumulation only occurred in the apoplast and this temporally coincided with the fumigation period. The inhibitor experiments suggested that both the plasma membrane-bound NAD(P)H oxidase complex and cell-wall NAD(P)H PODs contributed to H2O2 generation. To investigate the mechanisms responsible for O3-induced H2O2 accumulation further, both production and scavenging of H2O2 were investigated in the extracellular matrix after subcellular fractionation. The results indicated that H2O2 accumulation is a complex and highly regulated event requiring the time-dependent stimulation and down-regulation of differently located enzymes, some of which are involved in H2O2 generation and degradation, not only during the fumigation period but also in the subsequent recovery period in non-polluted air. Owing to the possible interplay between H2O2 and ethylene, the time-course of ethylene emission was analysed too. Ethylene was rapidly emitted following O3 exposure, but it declined to control values as early as after 4 h of exposure. The early contemporaneous detection of increased ethylene and H2O2 levels after 30 min of exposure does not allow a clear temporal relationship between these two signalling molecules to be established.
Pulse-amplitude modulated microfluorometry and an extracellular pH microprobe were used to examine light-induced spatial heterogeneity of photosynthetic and H(+)-transporting activities in cells of Chara corallina Klein ex Willd. Subcellular domains featuring different PSII photochemical activities were found to conform to alternate alkaline and acid zones produced near the cell surface, with peaks of PSII activity correlating with the position of acid zones. Buffers eliminated pH variations near the cell surface but did not destroy the variations in PSII photochemical yield (deltaF/Fm'). When a dark-adapted cell was exposed to actinic light, the PSII effective yield decreased within 5-15 min in the alkaline regions but rose after the initial decline in the acid regions. The light-induced decrease in deltaF/Fm' in the alkaline regions occurred prior to or synchronously with the steep rise in local pH. The kinetics of deltaF/Fm', Fm', and F observed in alkaline regions under overall illumination of Chara cells were replaced by those typical of acid regions, when the illumination area size was restricted to 1.5-2 mm. The data show that photoinduced patterns in photosynthetic activity are not predetermined by the particular structural organization of alkaline and acid cell regions but are subject to dynamic changes.