Among four cultivars of Brassica juncea L., viz., TM-4, TM-2, RH-30, and T-59, cv. T-59 was relatively more tolerant to nickel (Ni) toxicity based on the growth parameters, seedling vigor index, and metal tolerance index. Nickel application inhibited the activity of the nitrate-assimilating enzyme nitrate reductase in the roots, stem, and leaves, whereas the total organic nitrogen, proline, and activity of a polyamine-metabolizing enzyme, diamine oxidase, increased in this tolerant cultivar (T-59). It accumulated a good amount of Ni from the soil in its root and shoot (i.e., 6.0–6.51 μg Ni g?1 dry weight) during 2 months of cultivation with an 8.0 mM Ni supply in the soil. The data presented in this paper indicate that Ni tolerance and its removal by Indian mustard from subtropical Indian soil is cultivar dependent, possibly due to different genetic and physiological adaptations of the cultivars. 相似文献
The neuritogenic effect of exogenous ganglioside has been documented with a variety of neuronal and neuroblastoma systems, but the mechanism is not understood. Involvement of Ca2+ is suggested by this study which demonstrates that treatment of Neuro-2A cells with bovine brain gangliosides (BBG) in Ca2(+)-depleted medium failed to produce neurite outgrowth. This was in contrast to treatment with retinoic acid or dibutyryl cyclic AMP which induced differentiation under the same conditions. Addition of BBG to Neuro-2A cells caused small, but significant, increases in both influx and efflux of Ca2+. It thus appears that although neuritogenesis can proceed by more than one mechanism, that induced by BBG requires exogenous Ca2+ and involves stimulation of Ca2+ flux. 相似文献
Highly purified rat brain myelin showed a significant level of ethanolamine kinase, amounting to 17% of the specific activity of whole brain homogenate. This kinase level in myelin was an order of magnitude higher than that of lactate dehydrogenase, a marker for cytosol. Subcellular distribution studies revealed that in addition to myelin, this kinase was present in the P1, P2, P3, and cytosolic fractions with highest relative specific activity in the latter. The possibility that myelin activity resulted from adsorption of the soluble enzyme was unlikely since activity was retained in myelin that had been washed with buffered sodium chloride or taurocholate. Mixing experiments and repeated purification further indicated that the enzyme is intrinsic to myelin. Kinetic studies indicated similar Km values for ethanolamine in the microsomal, cytosolic, and myelin fractions but a significantly lower apparent Km for ATP in myelin. This and other differences suggested the possible existence of isozymes. Establishment of the presence of this kinase completes the list of phospholipid synthesizing enzymes needed to synthesize phosphatidylethanolamine from diacylglycerol within the myelin membrane. 相似文献
With the rapid advancements in processing and storage technology along with the popularity of the internet, computing capabilities have become more affordable, efficient, and widely accessible than ever before. This advancement has resulted in the emergence of a modern computing environment known as fog computing. Due to the latency-sensitiveness feature, computation of these services in fog computing is advantageous than cloud. Task scheduling is a significant issue in fog systems and substantially impacts resource utilization, task computation, and latency time. Many heuristic and meta-heuristic techniques have been applied to solve the scheduling issue. For the success of any meta-heuristic algorithm, an appropriate composition of exploration and exploitation of solution space is required to improve convergence and avoid local optima. To meet these requirements, a modified fireworks algorithm with the combination of opposition-based learning and differential evolution techniques is presented. Differential evolution operator has been utilized to avoid local optima and opposition-based learning technique has been applied for creating a diversified solution set of population. The proposed method works on the minimization of makespan and cost and improves resource utilization. The experiments have been carried out on a variety of workloads, and the findings have been compared with some recent popular metaheuristic techniques. The comparison has verified the importance of the proposed approach.
The optimization of our previous lead compound 1 (AChE IC50 = 3.31 μM) through synthesis and pharmacology of a series of novel carbamates is reported. The synthesized compounds were evaluated against mouse brain AChE enzyme using the colorimetric method described by Ellman et al. The three compounds 6a (IC50 = 2.57 μM), 6b (IC50 = 0.70 μM) and 6i (IC50 = 2.56 μM) exhibited potent in vitro AChE inhibitory activities comparable to the drug rivastigmine (IC50 = 1.11 μM). Among them, the compound 6b has been selected as possible optimized lead for further neuropharmacological studies. In addition, the AChE–carbamate Michaelis complexes of these potent compounds including rivastigmine and ganstigmine have been modeled using covalent docking protocol of GOLD and important direct/indirect interactions contributing to stabilization of the AChE–carbamate Michaelis complexes have been investigated. 相似文献
Twenty-seven enzyme systems, six random amplified polymorphic DNA (RAPD) primers, and two microsatellite loci were tested to determine intraspecific divergence in the natural population of the endangered Indian featherback fish, Chitala chitala, for the first time. The 262 samples of C. chitala were collected from six riverine locations in India: the Satluj, Ganga (Ghagra, Bhagirathi, and Brahmaputra), Mahanadi, and Narmada river systems. The analysis revealed population subdivisions, with an FST value from 0.1235 (95% confidence 0.0868–0.1621) for RAPD and a combined FST of 0.0344 (95% confidence 0.0340–0.0350) for microsatellite loci. An analysis of 38 allozyme loci did not reveal any polymorphism in the samples from any of the riverine localities; a possible explanation for this could be that the ancestors of Chitala could have faced a population reduction in prehistoric periods, as low allozyme variation is also reported for other species of Chitala from south Asia. 相似文献
A new class of copper(II) nanohybrid solids, LCu(CH3COO)2 and LCuCl2, have been synthesized and characterized by transmission electron microscopy, dynamic light scattering, and IR spectroscopy,
and have been found to be capped by a bis(benzimidazole) diamide ligand (L). The particle sizes of these nanohybrid solids
were found to be in the ranges 5–10 and 60–70 nm, respectively. These nanohybrid solids were evaluated for their in vitro
antimalarial activity against a chloroquine-sensitive isolate of Plasmodium falciparum (MRC 2). The interactions between these nanohybrid solids and plasmepsin II (an aspartic protease and a plausible novel target
for antimalarial drug development), which is believed to be essential for hemoglobin degradation by the parasite, have been
assayed by UV–vis spectroscopy and inhibition kinetics using Lineweaver–Burk plots. Our results suggest that these two compounds
have antimalarial activities, and the IC50 values (0.025–0.032 μg/ml) are similar to the IC50 value of the standard drug chloroquine used in the bioassay. Lineweaver–Burk plots for inhibition of plasmepsin II by LCu(CH3COO)2 and LCuCl2 show that the inhibition is competitive with respect to the substrate. The inhibition constants of LCu(CH3COO)2 and LCuCl2 were found to be 10 and 13 μM, respectively. The IC50 values for inhibition of plasmepsin II by LCu(CH3COO)2 and LCuCl2 were found to be 14 and 17 μM, respectively. Copper(II) metal capped by a benzimidazole group, which resembles the histidine
group of copper proteins (galactose oxidase, β-hydroxylase), could provide a suitable anchoring site on the nanosurface and
thus could be useful for inhibition of target enzymes via binding to the S1/S3 pocket of the enzyme hydrophobically. Both
copper(II) nanohybrid solids were found to be nontoxic against human hepatocellular carcinoma cells and were highly selective
for plasmepsin II versus human cathepsin D. The pivotal mechanism of antimalarial activity of these compounds via plasmepsin
II inhibition in the P. falciparum malaria parasite is demonstrated. 相似文献
δ subunit-containing γ-aminobutyric acid, type A (GABAA)receptors are expressed extrasynaptically and mediate tonic inhibition. In cerebellar granule cells, they often form receptors together with α1 and/or α6 subunits. We were interested in determining the architecture of receptors containing both subunits. We predefined the subunit arrangement of several different GABAA receptor pentamers by concatenation. These receptors composed of α1, α6, β3, and δ subunits were expressed in Xenopus oocytes. Currents elicited in response to GABA were determined in the presence and absence of 3α,21-dihydroxy-5α-pregnan-20-one (THDOC) or ethanol, or currents were elicited by 4,5,6,7-tetrahydroisoxazolo[5,4-c]-pyridin-3-ol (THIP). Several subunit configurations formed active channels. We therefore conclude that δ can assume multiple positions in a receptor pentamer made up of α1, α6, β3, and δ subunits. The different receptors differ in their functional properties. Functional expression of one receptor type was only evident in the combined presence of the neurosteroid THDOC with the channel agonist GABA. Most, but not all, receptors active with GABA/THDOC responded to THIP. None of the receptors was modulated by ethanol concentrations up to 30 mm. Several observations point to a preferred position of δ subunits between two α subunits in α1α6β3δ receptors. This property is shared by α1β3δ and α6β3δ receptors, but there are differences in the additionally expressed isoforms. 相似文献