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151.
The sub-cellular feruloylation and oxidative coupling sites of cell wall polysaccharides were investigated in planta by monitoring
the kinetics of appearance of arabinosyl- and feruloyl-radiolabelled polysaccharides in the protoplasmic compartment and their
secretion in the wall either in the presence or absence of brefeldin A (BFA). By using root apical segments excised from wheat
seedlings (Triticum durum Desf.), incubated with trans-[U-14C]cinnamic acid, we demonstrated that [14C]ferulate, likely [14C]diferulate, as well as trimers and larger products of ferulate are incorporated into the protoplasmic polysaccharides very
rapidly within 1–3 min of [14C]cinnamate feeding. This agrees with the assumption that (glucurono)arabinoxylans [(G)AX] feruloylation and oxidative coupling
occur intracellularly, likely in the Golgi apparatus. Simultaneously, polymer bound radioactive hydroxycinnamic acids appeared
to be incorporated into the cell wall of root apical segments as early as 2 min after trans-[U-14C]cinnamic acid feeding. On the contrary, starting from l-[1-14C]arabinose as tracer, the secretion of the pentose-containing polymers into the wall was between 5 to 10 min. These results
indicated that (G)AX feruloylation and oxidative coupling occur both intra-protoplasmically and in muro. The occurrence of
in muro feruloylation and oxidative coupling was confirmed by the use of BFA a well known inhibitor of secretion. The drug
caused a strong inhibition of the synthesis and secretion into the wall of the 14C-pentosyl-labelled polymers as well as of 14C-feruloyl-polymers. In spite of this, the total amount of 14C-feruloyl-polymers incorporated into the wall was only slightly affected by BFA. This indicates the existence of a mechanism
involved into secretion of the activated hydroxycinnamoyl precursors to the wall, alternative to that involved in polysaccharide
secretion.
Lucia Ilenia Mastrangelo and Marcello Salvatore Lenucci equally contributed to this work. 相似文献
152.
Khondoker MR Bachmann TT Mewissen M Dickinson P Dobrzelecki B Campbell CJ Mount AR Walton AJ Crain J Schulze H Giraud G Ross AJ Ciani I Ember SW Tlili C Terry JG Grant E McDonnell N Ghazal P 《Journal of bioinformatics and computational biology》2010,8(6):945-965
Machine learning and statistical model based classifiers have increasingly been used with more complex and high dimensional biological data obtained from high-throughput technologies. Understanding the impact of various factors associated with large and complex microarray datasets on the predictive performance of classifiers is computationally intensive, under investigated, yet vital in determining the optimal number of biomarkers for various classification purposes aimed towards improved detection, diagnosis, and therapeutic monitoring of diseases. We investigate the impact of microarray based data characteristics on the predictive performance for various classification rules using simulation studies. Our investigation using Random Forest, Support Vector Machines, Linear Discriminant Analysis and k-Nearest Neighbour shows that the predictive performance of classifiers is strongly influenced by training set size, biological and technical variability, replication, fold change and correlation between biomarkers. Optimal number of biomarkers for a classification problem should therefore be estimated taking account of the impact of all these factors. A database of average generalization errors is built for various combinations of these factors. The database of generalization errors can be used for estimating the optimal number of biomarkers for given levels of predictive accuracy as a function of these factors. Examples show that curves from actual biological data resemble that of simulated data with corresponding levels of data characteristics. An R package optBiomarker implementing the method is freely available for academic use from the Comprehensive R Archive Network (http://www.cran.r-project.org/web/packages/optBiomarker/). 相似文献
153.
154.
NF-κB p50/RelA and c-Rel-containing dimers: opposite regulators of neuron vulnerability to ischaemia
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156.
Vasanth S Murali Ruhung Wang Carole A Mikoryak Paul Pantano Rockford Draper 《Experimental biology and medicine (Maywood, N.J.)》2015,240(9):1147-1151
Polyethylene glycol (PEG) and related polymers are often used in the functionalization of carbon nanomaterials in procedures that involve sonication. However, PEG is very sensitive to sonolytic degradation and PEG degradation products can be toxic to mammalian cells. Thus, it is imperative to assess potential PEG degradation to ensure that the final material does not contain undocumented contaminants that can introduce artifacts into experimental results. Described here is a simple and inexpensive polyacrylamide gel electrophoresis method to detect the sonolytic degradation of PEG. The method was used to monitor the integrity of PEG phospholipid constructs and branched chain PEGs after different sonication times. This approach not only helps detect degraded PEG, but should also facilitate rapid screening of sonication parameters to find optimal conditions that minimize PEG damage. 相似文献
157.
Hadi N Yehia Rockford K Draper Carole Mikoryak Erin Kate Walker Pooja Bajaj Inga H Musselman Meredith C Daigrepont Gregg R Dieckmann Paul Pantano 《Journal of nanobiotechnology》2007,5(1):8-17
This work concerns exposing cultured human epithelial-like HeLa cells to single-walled carbon nanotubes (SWNTs) dispersed
in cell culture media supplemented with serum. First, the as-received CoMoCAT SWNT-containing powder was characterized using
scanning electron microscopy and thermal gravimetric analyses. Characterizations of the purified dispersions, termed DM-SWNTs,
involved atomic force microscopy, inductively coupled plasma – mass spectrometry, and absorption and Raman spectroscopies.
Confocal microRaman spectroscopy was used to demonstrate that DM-SWNTs were taken up by HeLa cells in a time- and temperature-dependent
fashion. Transmission electron microscopy revealed SWNT-like material in intracellular vacuoles. The morphologies and growth
rates of HeLa cells exposed to DM-SWNTs were statistically similar to control cells over the course of 4 d. Finally, flow
cytometry was used to show that the fluorescence from MitoSOX™ Red, a selective indicator of superoxide in mitochondria, was
statistically similar in both control cells and cells incubated in DM-SWNTs. The combined results indicate that under our
sample preparation protocols and assay conditions, CoMoCAT DM-SWNT dispersions are not inherently cytotoxic to HeLa cells.
We conclude with recommendations for improving the accuracy and comparability of carbon nanotube (CNT) cytotoxicity reports. 相似文献
158.
Ilenia Masi Valentina Caprara Francesca Spadaro Lidia Chellini Rosanna Sestito Andrea Zancla Alberto Rainer Anna Bagnato Laura Rosanò 《Cell reports》2021,34(9):108800
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159.
Serafino Pantano Valérie Dubost Katy Darribat Philippe Couttet Olivier Grenet Steven Busch Pierre Moulin 《Journal of molecular histology》2013,44(6):733-747
Dipeptidyl peptidase IV (DPP4) is a peptidase whose inhibition is beneficial in Type II diabetes treatment. Several evidences suggest potential implication of DPP4 in skin disorders such as psoriasis, keloids and fibrotic skin diseases where its inhibition could also be beneficial. DPP4 expression in human skin was described mainly in dermal fibroblasts and a subset of keratinocytes in the basal layer. Of importance in the perspective of preclinical experimentation, DPP4 distribution in skin of non-human primate species has not been documented. This report evidences unexpected differences between a set of human and cynomolgus monkey skin samples revealing a major expression of DPP4 in eccrine sweat glands of cynomolgus monkeys but not in humans. This represents a unique distinctive feature compared to the conserved expression of dipeptidyl peptidases 8 and 9 and potential relevant DPP4 substrates such as neuropeptide Y (NPY) and receptors (NPY-receptor 1 and Neurokinin receptor). Finally the observation that cathepsin D, an unrelated protease, shows the opposite expression compared to DPP4 (present in human but not in cynomolgus monkey eccrine sweat glands) could indicate that human eccrine sweat glands evolved a divergent protease repertoire compared to non-human primates. These unexpected differences in the eccrine sweat glands protease repertoire will need to be confirmed extending the analysis to a major number of donors but could imply possible biochemical divergences, reflecting the functional evolution of the glands and the control of their activity. Our findings also demonstrate that non-human primates studies aiming at understanding DPP4 function in skin biology are not readily translatable to human. 相似文献
160.