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81.
Artur Pinski Alexander Betekhtin Jolanta Kwasniewska Lukasz Chajec Elzbieta Wolny Robert Hasterok 《International journal of molecular sciences》2021,22(14)
As cell wall proteins, the hydroxyproline-rich glycoproteins (HRGPs) take part in plant growth and various developmental processes. To fulfil their functions, HRGPs, extensins (EXTs) in particular, undergo the hydroxylation of proline by the prolyl-4-hydroxylases. The activity of these enzymes can be inhibited with 3,4-dehydro-L-proline (3,4-DHP), which enables its application to reveal the functions of the HRGPs. Thus, to study the involvement of HRGPs in the development of root hairs and roots, we treated seedlings of Brachypodium distachyon with 250 µM, 500 µM, and 750 µM of 3,4-DHP. The histological observations showed that the root epidermis cells and the cortex cells beneath them ruptured. The immunostaining experiments using the JIM20 antibody, which recognizes the EXT epitopes, demonstrated the higher abundance of this epitope in the control compared to the treated samples. The transmission electron microscopy analyses revealed morphological and ultrastructural features that are typical for the vacuolar-type of cell death. Using the TUNEL test (terminal deoxynucleotidyl transferase dUTP nick end labelling), we showed an increase in the number of nuclei with damaged DNA in the roots that had been treated with 3,4-DHP compared to the control. Finally, an analysis of two metacaspases’ gene activity revealed an increase in their expression in the treated roots. Altogether, our results show that inhibiting the prolyl-4-hydroxylases with 3,4-DHP results in a vacuolar-type of cell death in roots, thereby highlighting the important role of HRGPs in root hair development and root growth. 相似文献
82.
Dawid Ponka Marta D. Winiewska Manuel D. Peris-Díaz Artur Krel Arkadiusz M. Bonna Wojciech Bal 《International journal of molecular sciences》2022,23(24)
Hepcidin (DTHFPICIFCCGCCHRSKCGMCCKT), an iron-regulatory hormone, is a 25-amino-acid peptide with four intramolecular disulfide bonds circulating in blood. Its hormonal activity is indirect and consists of marking ferroportin-1 (an iron exporter) for degradation. Hepcidin biosynthesis involves the N-terminally extended precursors prepro-hepcidin and pro-hepcidin, processed by peptidases to the final 25-peptide form. A sequence-specific formation of disulfide bonds and export of the oxidized peptide to the bloodstream follows. In this study we considered the fact that prior to export, reduced hepcidin may function as an octathiol ligand bearing some resemblance to the N-terminal part of the α-domain of metallothioneins. Consequently, we studied its ability to bind Zn(II) and Cd(II) ions using the original peptide and a model for prohepcidin extended N-terminally with a stretch of five arginine residues (5R-hepcidin). We found that both form equivalent mononuclear complexes with two Zn(II) or Cd(II) ions saturating all eight Cys residues. The average affinity at pH 7.4, determined from pH-metric spectroscopic titrations, is 1010.1 M−1 for Zn(II) ions; Cd(II) ions bind with affinities of 1015.2 M−1 and 1014.1 M−1. Using mass spectrometry and 5R-hepcidin we demonstrated that hepcidin can compete for Cd(II) ions with metallothionein-2, a cellular cadmium target. This study enabled us to conclude that hepcidin binds Zn(II) and Cd(II) sufficiently strongly to participate in zinc physiology and cadmium toxicity under intracellular conditions. 相似文献
83.
Investigations of ion-molecule reactions were performed for methane-carbon tetrafluoride mixtures of different compositions. Concentration of methane in these mixtures ranged from 10% to 90% (at 10% increment) and total mixture pressure was fixed at 13.3 Pa. Measurements were made using a quadrupole mass spectrometer with a high-pressure ion source. Primary ions CH4+, F+, CF+ and CF3+ were produced by electrons with energy of 300 eV. Secondary ions CH5+, C2H3+, C2H4+, C2H5+, C2H7+ and CF3+ were observed as the result of ion-molecule reactions.The influence of repeller potential on ion-molecule reactions efficiency was examined. 相似文献
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86.
Lea Heikinheimo Arja Miettinen‐Oinonen Artur Cavaco‐Paulo Johanna Buchert 《应用聚合物科学杂志》2003,90(7):1917-1922
The mode of action of monocomponent purified Trichoderma reesei cellobiohydrolases (CBHI and CBHII) and endoglucanases (EGI and EGII) on cotton fabrics was studied by analyzing the weight loss of the fabric, the reducing sugars, the soluble oligosaccharides and the molecular weight of the cotton powder formed. The impact of mechanical action on these factors was also evaluated. EGI and EGII released the highest amounts of reducing sugars and soluble oligosaccharides in both treatments with or without additional mechanical action. After cellulase treatment without additional mechanical action, all of the cellulases were found to have reduced the molecular weight of cotton poplin powder. When mechanical action was combined with enzyme treatments, only EGII reduced the molecular weight. The weight loss of EG‐treated fabrics was clearly higher than the weight loss of CBH‐treated fabrics with both low and high mechanical action levels. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1917–1922, 2003 相似文献
87.
Artur Manuel Ribeiro dos Santos Caldas de Matos Reiji Suzuki Takaya Arita 《Artificial Life and Robotics》2007,11(2):175-182
Recent studies in evolutionary computation have focused on using developmental processes together with genetic algorithms
in order to achieve more complex designs. Although several models have been proposed, their growth dynamics, and their interactions
with evolutionary algorithms are still poorly understood. One particularly neglected concept in artificial developmental systems
is heterochrony: how evolution affects development by changing the timing and rate of developmental events. In this article we attempt to
address this issue by analyzing heterochronic changes in a well-known artificial developmental model, the cellular encoding
model, by using a previously developed heterochrony framework. We have conducted experiments by evolving networks to solve
a Boolean problem, and analyzed heterochronic changes in both successful and unsuccessful runs. Our findings show that owing
to its properties, the cellular encoding model strongly affects the developmental dynamics and the heterochronic changes that
occur during evolution. Our experiments also show that hypermorphic changes (a kind of heterochronic occurrence) lead to greater
evolvability in successful runs. 相似文献
88.
Hydrodynamische Einlauflänge und Widerstandsgesetz von reibungsmindernden kationschen Tensidlösungen
Dipl.-Ing. Hans-Heinrich Kleuker cand. ing. Anke Laurenzis Dr.-Ing. Wilhelm Althaus Dr.-Ing. Artur Steiff Prof. Dr.-Ing. Paul-Michael Weinspach 《Forschung im Ingenieurwesen》1993,59(1-2):8-18
Zusammenfassung Durch Zugabe geeigneter Tensidsysteme in Wasser kann der Str?mungsdruckverlust in geraden Rohren erheblich gesenkt werden.
Die diesem Effekt zugrunde liegenden Mechanismen wurden in früheren Arbeiten eingehend diskutiert. In dieser Arbeit werden
neue Ergebnisse vorgestellt, die sowohl die Bestimmung der hydrodynamischen Einlaufl?nge als auch die Ermittlung der Widerstandsbeiwerte
im ausgebildeten Str?mungszustand erm?glichen. Für den Bereich der ausgebildeten Rohrstr?mung wird eine neue Berechnungsgleichung
vorgeschlagen. Durch Erweiterung der bisherigen Modellvorstellungen ergibt sich ein Widerstandsgesetz für den gesamten Wirkungsbereich
des Tensids. Die Ergebnisse stützen sich auf Untersuchungen mit zwei verschiedenen Additivsystemen, bei denen die Parameter
Str?mungsgeschwindigkeit, Temperatur und Einsatzkonzentration variiert wurden. 相似文献
89.
90.
In three-phase systems, where the liquid constitutes the continuous phase, solid is the catalyst and gas represents the dispersed phase, there are decisive criteria which have to be observed in reactor design. These are e.g. the interfacial area per unit volume between gas and liquid, the volumetric mass transfer coefficient and the mass transfer coefficient. The basic aim of the present work was therefore the investigation of these parameters in relation to the main influencing parameters. Process parameters stirrer speed and superficial gas velocity were varied as well as the physical properties such as liquid viscosity, solids concentration, particle diameter and a geometrical parameter, i.e. reactor diameter. The sulphite method was employed for the determination of these values. The test results confirmed the known relationships of power consumption and superficial gas velocity. An increase in the liquid viscosity leads to a decrease in all the tested values. In most cases, suspended solid particles lead to a lowering of the test values. The influence of the tank diameter on the plots of the test values against specific power consumption turned out to be invariant so that a scale-up of geometrically similar systems can be carried out at constant power consumption, superficial gas velocity and liquid viscosity. 相似文献