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81.
82.
Yukihiko Hayashi Moto Kitayaki Kayoko Takezaki Hidekazu Ikeuchi Shigeru Kunugi 《Biocatalysis and Biotransformation》2013,31(1):25-31
The contribution of three exoglucanases from a commercial Trichoderma viride cellulase to transcellobiosylation, and the tolerance of these enzymes to acetonitrile co-solvent were studied. The enzymatic reactions were performed with p-nitrophenyl-β-d-cellobioside as the starting substrate. Among these enzymes, the least anionic exoglucanase (Exo I) showed the highest transcellobiosylation activity and acetonitrile tolerance. Exo I retained considerable activity even in 30% MeCN/water and produced p-nitrophenyl-β-d-cellotetraoside at about 1.5% conversion from the initial substrate in 30% MeCN/water. The residual activity of Exo I after incubation in MeCN/water mixture was almost identical to that of the crude cellulase and a considerable amount of the transcellobiosylation properties of the crude cellulase seemed to be attributable to this Exo I component. 相似文献
83.
Lu Gao Kejian Peng Yan Xia Guiping Wang Liyuan Niu Chunlan Lian 《International journal of phytoremediation》2013,15(4):307-319
Phytolacca americana L. can accumulate large amounts of heavy metals in its aerial tissues, especially cadmium (Cd) and manganese (Mn). It has great potential for use in phytoextraction of metals from multi-metal-contaminated soils. This study was conducted to further investigate the Cd- and Mn-tolerance strategies of this plant. Concentrations of non-protein thiols (NPTs) and phytochelatins (PCs) in leaves and roots increased significantly as the concentration of Cd in solution increased. The molar ratios of PCs:soluble Cd ranged from 1.8 to 3.6 in roots and 8.1 to 31.6 in leaves, suggesting that the cellular response involving PC synthesis was sufficient to complex Cd ions in the cytosol, especially that of leaves. In contrast, excess Mn treatments did not result in a significant increase in NPT or PC concentrations in leaves or roots. Oxalic acid concentrations in leaves of plants exposed to 2 or 20 mM Mn reached 69.4 to 89.3 mg (0.771 to 0.992 mmol) g–1 dry weight, respectively, which was approximately 3.7- to 8.6-fold higher than the Mn level in the 0.6 M HCl extract. Thus, oxalic acid may play an important role in the detoxification of Mn. 相似文献
84.
《Electromagnetic biology and medicine》2013,32(2):143-150
Two different pre-sowing techniques have been investigated for their influence in an important industrial plant, namely cotton. Priming methods are very useful for agricultural practices because they improve crop seedling establishment, especially when environmental conditions are not optimum. Pulsed electromagnetic fields have been found to promote germination and improve early growth characteristics of cotton seedlings. Such priming techniques are especially valuable in organic cultivation, where chemical compounds are prohibited. PEG treatment showed an enhancement in some measurements, however in some cases the results were not statistically different compared to control plants. In addition, PEG treatment is a sophisticated method that is far from agricultural practices and farmers. In this research, two different ages of seeds were used (1- and 2-year-old) in order to investigate the promotory effects of priming techniques. Magnetic field treatment of 15 min was found to stimulate germination percentage and to promote seeds, resulting in 85% higher values than control seeds under real field conditions. Furthermore, seeds that were treated with magnetic field performed better in terms of early-stage measurements and root characteristics. 相似文献
85.
Derek D. Lovingood Jeffrey R. Owens Michael Seeber Konstantin G. Kornev Igor Luzinov 《Journal of visualized experiments : JoVE》2013,(82)
Microwave-assisted synthetic techniques were used to quickly and reproducibly produce silica nanoparticle sols using an acid catalyst with nanoparticle diameters ranging from 30-250 nm by varying the reaction conditions. Through the selection of a microwave compatible solvent, silicic acid precursor, catalyst, and microwave irradiation time, these microwave-assisted methods were capable of overcoming the previously reported shortcomings associated with synthesis of silica nanoparticles using microwave reactors. The siloxane precursor was hydrolyzed using the acid catalyst, HCl. Acetone, a low-tan δ solvent, mediates the condensation reactions and has minimal interaction with the electromagnetic field. Condensation reactions begin when the silicic acid precursor couples with the microwave radiation, leading to silica nanoparticle sol formation. The silica nanoparticles were characterized by dynamic light scattering data and scanning electron microscopy, which show the materials'' morphology and size to be dependent on the reaction conditions. Microwave-assisted reactions produce silica nanoparticles with roughened textured surfaces that are atypical for silica sols produced by Stöber''s methods, which have smooth surfaces. 相似文献
86.
The response to tissue damage is a complex process, which involves the coordinated regulation of multiple proteins to ensure tissue repair. In order to investigate the effect of tissue damage in a lower vertebrate, samples were taken from rainbow trout (Oncorhynchus mykiss) at day 7 after damage and proteins were separated using 2DE. The experimental design included two groups of rainbow trout, which were fed organic feed either with or without astaxanthin. In total, 96 proteins were found to be affected by tissue damage, clearly demonstrating in this lower vertebrate the complexity and magnitude of the cellular response, in the context of a regenerative process. Using a bioinformatics approach, the main biological function of these proteins were assigned, showing the regulation of proteins involved in processes such as apoptosis, iron homeostasis, and regulation of muscular structure. Interestingly, it was established that exclusively within the astaxanthin feed group, three members of the annexin protein family (annexin IV, V, and VI) were regulated in response to tissue damage. 相似文献
87.
Qurra-tul-Ann Afza Gardner Hooria Younas Muhammad Akhtar 《Biochimica et Biophysica Acta - Proteins and Proteomics》2013,1834(1):182-190
Human M-proinsulin was cleaved by trypsin at the R31R32–E33 and K64R65–G66 bonds (B/C and C/A junctions), showing the same cleavage specificity as exhibited by prohormone convertases 1 and 2 respectively. Buffalo/bovine M-proinsulin was also cleaved by trypsin at the K59R60–G61 bond but at the B/C junction cleavage occurred at the R31R32–E33 as well as the R31–R32E33 bond. Thus, the human isoform in the native state, with a 31 residue connecting C-peptide, seems to have a unique structure around the B/C and C/A junctions and cleavage at these sites is predominantly governed by the structure of the proinsulin itself. In the case of both the proinsulin species the cleavage at the B/C junction was preferred (65%) over that at the C/A junction (35%) supporting the earlier suggestion of the presence of some form of secondary structure at the C/A junction. Proinsulin and its derivatives, as natural substrates for trypsin, were used and mass spectrometric analysis showed that the kcat./Km values for the cleavage were most favourable for the scission of the bonds at the two junctions (1.02 ± 0.08 × 105 s− 1 M− 1) and the cleavage of the K29–T30 bond of M-insulin-RR (1.3 ± 0.07 × 105 s− 1 M− 1). However, the K29–T30 bond in M-insulin, insulin as well as M-proinsulin was shielded from attack by trypsin (kcat./Km values around 1000 s− 1 M− 1). Hence, as the biosynthetic path follows the sequence; proinsulin → insulin-RR → insulin, the K29–T30 bond becomes shielded, exposed then shielded again respectively. 相似文献
88.
Background
This issue of “Biochimica et Biophysica Acta — General Subjects” is dedicated to organic bioelectronics, an interdisciplinary field that has been growing at a fast pace. Bioelectronics creates tremendous promise, excitement, and hype. The application of organic electronic materials in bioelectronics offers many opportunities and is fuelled by some unique features of these materials, such as the ability to transport ions.Scope of review
This is a perspective on the history and current status of the field.Major conclusions
Organic bioelectronics currently encompasses many different applications, including neural interfaces, tissue engineering, drug delivery, and biosensors. The interdisciplinary nature of the field necessitates collaborations across traditional scientific boundaries.General significance
Organic bioelectronics is a young and exciting interdisciplinary field. This article is part of a Special Issue entitled Organic Bioelectronics — Novel Applications in Biomedicine. 相似文献89.
Chu-Hua Lu Yu-Sheng Hsiao Chiung-Wen Kuo Peilin Chen 《Biochimica et Biophysica Acta (BBA)/General Subjects》2013
Background
Organic bioelectronic devices consisting of alternating poly(3,4-ethylenedioxythiophene) (PEDOT) and reduced graphite oxide (rGO) striped microelectrode arrays were fabricated by lithography technology. It has been demonstrated that the organic bioelectronic devices can be used to spatially and temporally manipulate the location and proliferation of the neuron-like pheochromocytoma cells (PC-12 cells).Methods
By coating an electrically labile contact repulsion layer of poly(l-lysine-graft-ethylene glycol) (PLL-g-PEG) on the PEDOT electrode, the location and polarity of the PC-12 cells were confined to the rGO electrodes.Results
The outgrowth of spatially confined bipolar neurites was found to align along the direction of the 20 μm wide electrode. The location of the PC-12 cells can also be manipulated temporally by applying electrical stimulation during the neurite differentiation of PC-12 cells, allowing the PC-12 cells to cross over the boundary between the PEDOT and the rGO regions and construct neurite networks in an unconfined manner where the contact repulsive coating of PLL-g-PEG was removed.Conclusions
This adsorption and desorption of the PLL-g-PEG without and with electrical stimulation can be attributed to the tunable surface properties of the PEDOT microelectrodes, whose surface charge can switch from being negative to positive under electrical stimulation.General significance
The electrically tunable organic bioelectronics reported here could potentially be applied to tissue engineering related to the development and regeneration of mammalian nervous systems. The spatial and temporal control in this device would also be used to study the synapse junctions of neuron–neuron contacts in both time and space domains. This article is part of a Special Issue entitled Organic Bioelectronics — Novel Applications in Biomedicine. 相似文献90.
A.M. Münzer K. MelzerM. Heimgreiter G. Scarpa 《Biochimica et Biophysica Acta (BBA)/General Subjects》2013