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991.
Federico J. Berli Rodrigo Alonso Ricardo Bressan‐Smith Rubén Bottini 《Physiologia plantarum》2013,149(1):127-140
We previously demonstrated that solar ultraviolet‐B (UV‐B) radiation levels in high altitude vineyards improve berry quality in Vitis vinifera cv. Malbec, but also reduce berry size and yield, possibly as a consequence of increased oxidative damage and growth reductions (lower photosynthesis). The defense mechanisms toward UV‐B signal and/or evoked damage promote production of antioxidant secondary metabolites instead of primary metabolites. Purportedly, the UV‐B effects will depend on tissues developmental stage and interplay with other environmental conditions, especially stressful situations. In this work, grapevines were exposed to high solar UV‐B (+UV‐B) and reduced (by filtering) UV‐B (?UV‐B) treatments during three consecutive seasons, and the effects of UV‐B, developmental stages and seasons on the physiology were studied, i.e. growth, tissues morphology, photosynthesis, photoprotective pigments, proline content and antioxidant capacity of leaves. The +UV‐B reduced photosynthesis and stomatal conductance, mainly through limitation in gas exchange, reducing plant's leaf area, net carbon fixation and growth. The +UV‐B augmented leaf thickness, and also the amounts of photoprotective pigments and proline, thereby increasing the antioxidant capacity of leaves. The defense mechanisms triggered by + UV‐B reduced lipid peroxidation, but they were insufficient to protect the photosynthetic pigments per leaf dry weight basis. The +UV‐B effects depend on tissues developmental stage and interplay with other environmental conditions such as total radiation and air temperatures. 相似文献
992.
Joaquín Herrero Francisco Fernández-Pérez Tatiana Yebra Esther Novo-Uzal Federico Pomar Mª Ángeles Pedreño Juan Cuello Alfredo Guéra Alberto Esteban-Carrasco José Miguel Zapata 《Planta》2013,237(6):1599-1612
Lignins result from the oxidative polymerization of three hydroxycinnamyl (p-coumaryl, coniferyl, and sinapyl) alcohols in a reaction mediated by peroxidases. The most important of these is the cationic peroxidase from Zinnia elegans (ZePrx), an enzyme considered to be responsible for the last step of lignification in this plant. Bibliographical evidence indicates that the arabidopsis peroxidase 72 (AtPrx72), which is homolog to ZePrx, could have an important role in lignification. For this reason, we performed a bioinformatic, histochemical, photosynthetic, and phenotypical and lignin composition analysis of an arabidopsis knock-out mutant of AtPrx72 with the aim of characterizing the effects that occurred due to the absence of expression of this peroxidase from the aspects of plant physiology such as vascular development, lignification, and photosynthesis. In silico analyses indicated a high homology between AtPrx72 and ZePrx, cell wall localization and probably optimal levels of translation of AtPrx72. The histochemical study revealed a low content in syringyl units and a decrease in the amount of lignin in the atprx72 mutant plants compared to WT. The atprx72 mutant plants grew more slowly than WT plants, with both smaller rosette and principal stem, and with fewer branches and siliques than the WT plants. Lastly, chlorophyll a fluorescence revealed a significant decrease in ΦPSII and q L in atprx72 mutant plants that could be related to changes in carbon partitioning and/or utilization of redox equivalents in arabidopsis metabolism. The results suggest an important role of AtPrx72 in lignin biosynthesis. In addition, knock-out plants were able to respond and adapt to an insufficiency of lignification. 相似文献
993.
Hua Li Giovanni Colica Pei-pei Wu Dunhai Li Federico Rossi Roberto De Philippis Yongding Liu 《Microbial ecology》2013,65(3):700-708
The supportive and negative evidence for the stress gradient hypothesis (SGH) led to an ongoing debate among ecologists and called for new empirical and theoretical work. In this study, we took various biological soil crust (BSCs) samples along a spatial gradient with four environmental stress levels to examine the fitness of SGH in microbial interactions and evaluate its influence on biodiversity–function relationships in BSCs. A new assessment method of species interactions within hard-cultured invisible soil community was employed, directly based on denaturing gradient gel electrophoresis fingerprint images. The results showed that biotic interactions in soil phototroph community dramatically shifted from facilitation to dominant competition with the improvement of microhabitats. It offered new evidence, which presented a different perspective on the hypothesis that the relative importance of facilitation and competition varies inversely along the gradient of abiotic stress. The path analysis indicated that influence of biotic interactions (r?=?0.19, p?<?0.05) on ecosystem functions is lower than other community properties (r?=?0.62, p?<?0.001), including soil moisture, crust coverage, and biodiversity. Furthermore, the correlation between species interactions and community properties was non-significant with low negative influence (r?=??0.27, p?>?0.05). We demonstrate that the inversion of biotic interaction as a response to the gradient of abiotic stresses existed not only in the visible plant community but also in the soil microbial community. 相似文献
994.
Carlos Passos Federico Reyes Bettina Tassino Gil G. Rosenthal Andrés González 《Ethology : formerly Zeitschrift fur Tierpsychologie》2013,119(10):891-897
Chemical communication is an important mediator of social interactions in fish, including mate recognition, mate choice and intrasexual competition. We used a simultaneous‐choice design to test the response of adult females of the annual killifish, Austrolebias reicherti, towards male‐conditioned water, both crude and fractionated into its polar and non‐polar components. Females preferred male‐conditioned water when tested both against control water and female‐conditioned water. The polar and non‐polar fractions of the male‐conditioned water were not significantly attractive, although a tendency was observed towards the non‐polar fraction. Our study shows that annual fish respond to the chemical cues of potential mates. The chemical channel is likely to be particularly important in the muddy ephemeral ponds in which they occur. 相似文献
995.
Recent advances in brain energy metabolism support the notion that glycogen in astrocytes is necessary for the clearance of neuronally-released K+ from the extracellular space. However, how the multiple metabolic pathways involved in K+-induced increase in glycogen turnover are regulated is only partly understood. Here we summarize the current knowledge about the mechanisms that control glycogen metabolism during enhanced K+ uptake. We also describe the action of the ubiquitous Na+/K+ ATPase for both ion transport and intracellular signaling cascades, and emphasize its importance in understanding the complex relation between glycogenolysis and K+ uptake. 相似文献
996.
Daniela Calzia Stefano Barabino Paolo Bianchini Greta Garbarino Michele Oneto Federico Caicci Alberto Diaspro Carlo Tacchetti Lucia Manni Simona Candiani Silvia Ravera Alessandro Morelli Carlo Enrico Traverso Isabella Panfoli 《Biology of the cell / under the auspices of the European Cell Biology Organization》2013,105(8):345-358
997.
998.
Averna M Stifanese R De Tullio R Minicucci L Cresta F Palena S Salamino F Pontremoli S Melloni E 《Biochimica et biophysica acta》2011,1812(12):1649-1657
We are here reporting that in peripheral blood mononuclear cells (PBMC) of patients homozygous for F508del-CFTR the calpain-calpastatin system undergoes a profound alteration. In fact, calpain basal activity, almost undetectable in control PBMC, becomes measurable at a significant extent in cells from cystic fibrosis (CF) patients, also due to a 40-60% decrease in both calpastatin protein and inhibitory activity. Constitutive protease activation in CF patients' cells induces a large accumulation of the mutated cystic fibrosis transmembrane conductance regulator (CFTR) in the 100kD+70kD split forms as well as a degradation of proteins associated to the CFTR complex. Specifically, the scaffolding protein Na(+)/H(+) exchanger 3 regulatory factor-1 (NHERF-1) is converted in two distinct fragments showing masses of 35kD and 20kD, being however the latter form the most represented one, thereby indicating that in CF-PBMC the CFTR complex undergoes a large disorganization. In conclusion, our observations are providing new information on the role of calpain in the regulation of plasma membrane ion conductance and provide additional evidence on the transition of this protease activity from a physiological to a pathological function. 相似文献
999.
1000.
Marta López-Sánchez Mariana Mu?oz-Esquerre Daniel Huertas José Gonzalez-Costello Jesús Ribas Federico Manresa Jordi Dorca Salud Santos 《PloS one》2013,8(6)