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131.
Two new mononuclear Fe(III) complexes, [FeCl3{PPh2(p-C6H4NMe2)-P}3](1) (PPh2(p-C6H4NMe2): 4-(dimethylamino)phenyldiphenylphosphine) and [FeCl3(PPh2py-P)(PPh2py-P,N)] (2) (PPh2py: diphenyl(2-pyridyl)phosphine) were synthesized by reacting anhydrous FeCl3 with respective ligand in acetonitrile solution under refluxing condition. Both the complexes were characterized by elemental analysis, FAB-Mass, FTIR, UV-Vis, ESR, Cyclic Voltammetry and magnetic measurement. The FAB mass spectra of complexes 1 and 2 show molecular ion peak at m/z 1078 [M]+ and m/z 687 [M−1]+, respectively, indicating mononuclear nature of the complexes. UV-Vis spectra of the complexes were consistent with low-spin, octahedral geometry. The variable temperature magnetic susceptibility measurement (73-323 K) of these complexes is also consistent with the paramagnetic nature of the complexes with a ground state spin S = ½. The Fe(III) centers of these two complexes remain low-spin, both at room temperature and liquid nitrogen temperature, was also indicated by the ESR analysis. Cyclic Voltammetry of both the complexes show an irreversible oxidation wave attributed to Fe3+ → Fe4+ + e− along with the peak for ligand oxidation. Theoretical calculations (B3LYP) of the complexes show that for complex 1, a trans geometry of the two phosphorous atoms and for complex 2, a mer,cis structures are the most favored geometrical isomer. TDDFT calculations were performed to interpret the observed bands in the UV-Visible spectra. 相似文献
132.
Purification and characterization of a solvent and detergent-stable novel protease from Bacillus cereus 总被引:1,自引:0,他引:1
Doddapaneni KK Tatineni R Vellanki RN Rachcha S Anabrolu N Narakuti V Mangamoori LN 《Microbiological research》2009,164(4):383-390
A protease-producing bacterium was isolated from slaughterhouse waste samples, Hyderabad, India. It was related to Bacillus cereus on the basis of 16S rRNA gene sequencing and biochemical properties. The protease was purified to homogeneity using ammonium sulfate precipitation, and ion exchange chromatography with a fold purification of 1.8 and a recovery of 49%. The enzyme had a relative molecular weight of 28 kDa, pH and temperature optima for this protease were 10 and 60 °C. The activity was stable between a pH range of 7.0 and 12.0. The activity was inhibited by EDTA and enhanced (four-fold) by Cu2+ ions indicating the presence of metalloprotease. The enzyme showed extreme stability and activity even in the presence of detergents and anionic surfactants. The enzyme also showed stability in the presence of organic solvents. 相似文献
133.
Sang-Chul Kim Li Kang Satish Nagaraj Elison B. Blancaflor Kirankumar S. Mysore Kent D. Chapman 《The Journal of biological chemistry》2009,284(49):34065-34074
Fatty acid amide hydrolase (FAAH) terminates the endocannabinoid signaling pathway that regulates numerous neurobehavioral processes in animals by hydrolyzing N-acylethanolamines (NAEs). Recently, an Arabidopsis FAAH homologue (AtFAAH) was identified, and several studies, especially those using AtFAAH overexpressing and knock-out lines, have suggested an in vivo role for FAAH in the catabolism of NAEs in plants. We previously reported that overexpression of AtFAAH in Arabidopsis resulted in accelerated seedling growth, and in seedlings that were insensitive to exogenous NAEs but hypersensitive to abscisic acid (ABA) and hypersusceptible to nonhost pathogens. Here we show that whereas the enhanced growth and NAE tolerance of the AtFAAH overexpressing seedlings depend on the catalytic activity of AtFAAH, hypersensitivity to ABA and hypersusceptibility to nonhost pathogens are independent of its enzymatic activity. Five amino acids known to be critical for rat FAAH activity are also conserved in AtFAAH (Lys-205, Ser-281, Ser-282, Ser-305, and Arg-307). Site-directed mutation of each of these conserved residues in AtFAAH abolished its hydrolytic activity when expressed in Escherichia coli, supporting a common catalytic mechanism in animal and plant FAAH enzymes. Overexpression of these inactive AtFAAH mutants in Arabidopsis showed no growth enhancement and no NAE tolerance, but still rendered the seedlings hypersensitive to ABA and hypersusceptible to nonhost pathogens to a degree similar to the overexpression of the native AtFAAH. Taken together, our findings suggest that the AtFAAH influences plant growth and interacts with ABA signaling and plant defense through distinctly different mechanisms. 相似文献
134.
Microbial reduction of toxic Cr6+ to the less toxic Cr3+ is potentially a useful bioremediation process. Among the matrices tested for whole cell immobilization of an efficient chromate-reducing
Streptomyces griseus strain, PVA-alginate was the most effective and was used for reduction of Cr(VI) in a bioreactor. Cr6+ reduction efficiency decreased as Cr6+ was increased from 2 to 12 mg l−1 but increased with an increase in biomass concentration. However, increasing the flow rate from 2 to 8 ml h−1 did not significantly affect Cr6+ reduction. The reduction was faster in simulated effluent than in synthetic medium and complete removal of 8 mg Cr6+ l−1 from effluent and synthetic medium occurred in 2 and 12 h, respectively. Our results indicate that immobilized S. griseus cells could be applied for the large-scale bioremediation of chromate-containing effluents and wastewaters. 相似文献
135.
Marie K. Walsh Rebecca A. Bombyk Ashwini Wagh Amanda Bingham Lisa M. Berreau 《Journal of Molecular Catalysis .B, Enzymatic》2009,60(3-4):171-177
Fatty acid sugar esters are non-ionic detergents with multiple uses in the cosmetic, food, and pharmaceutical industries. Of the many different sugar esters synthesized, lactose, a by-product of cheese manufacture, has not been investigated. The objective of this research was to investigate the synthesis of novel lactose monolaurate (LML) and sucrose monolaurate (as a comparison) (SML) using four different immobilized lipases in three different solvents at constant sugar, vinyl laurate, temperature, and enzyme concentrations. Overall, the solvent 2-methyl-2-butanol gave the highest yields and reactions rates for the synthesis of both LML and SML. Of the immobilized lipases, those from Pseudomonas cepacia, Mucor miehei and Thermomyces lanuginosus were effective depending on the sugar/solvent combination. Higher overall yields were obtained for the synthesis of LML with the differences in yields presumably due to the decreased solubility of sucrose as compared to lactose in 3 of the solvents used. Response surface methodology was used to determine the optimal temperature, enzyme concentration and ratio of reactants for LML synthesis using the immobilized lipase from M. miehei in 2-methyl-2-butanol. Based on the analysis of ridge max, the optimal synthesis conditions were predicted to occur at 61 °C, with an enzyme amount of 32 mg/mL, and a molar ratio of lactose to vinyl laurate of 1:3.8; and the optimal actual yield was 99.3%. 相似文献
136.
L1-type cell adhesion molecules (CAMs) are important mediators of neural differentiation, including axonal outgrowth and pathfinding
and also of synapse formation and maintenance. In addition, their interactions with cytoskeletal components are highly conserved
and regulated. How these different aspects of CAM functionality relate to each other is not well understood. Based on results
from our and other laboratories we propose that ankyrin-binding to L1-type CAMs provides a master switch. The interaction
with ankyrins directs L1-type adhesive proteins into different functional contexts, either ankyrin-independent functions,
such as neurite outgrowth and axonal pathfinding or into ankyrin-dependent functions, such as L1’s role at axon initial segments
(AIS), paranodal regions, synapses and in dendrites.
The content of this Mini review was first presented in a shortened form at the 12th Mejbaum-Katzenellenbogen Seminar “Membrane
Skeleton. Recent Advances and Future Research Directions”, June 15–18, 2008, Zakopane, Poland 相似文献
137.
Sojan Abraham Ashwini Sankrepatna Nagaraj Soumen Basak Ramanathapuram Manjunath 《Journal of virology》2010,84(11):5485-5493
138.
Accuracy and Reliability of Pallor for Detecting Anaemia: A Hospital-Based Diagnostic Accuracy Study
Ashwini Kalantri Mandar Karambelkar Rajnish Joshi Shriprakash Kalantri Ulhas Jajoo 《PloS one》2010,5(1)
Background
Anaemia is a common disorder. Most health providers in resource poor settings rely on physical signs to diagnose anaemia. We aimed to determine the diagnostic accuracy of pallor for anaemia by using haemoglobin as the reference standard.Methodology/Principal Findings
In May 2007, we enrolled consecutive patients over 12 years of age, able to consent and willing to participate and who had a haemoglobin measurement taken within a day of assessment of clinical pallor from outpatient and medicine inpatient department of a teaching hospital. We did a blind and independent comparison of physical signs (examination of conjunctivae, tongue, palms and nailbed for pallor) and the reference standard (haemoglobin estimation by an electronic cell counter). Diagnostic accuracy was measured by calculating likelihood ratio values and 95% confidence intervals (CI) at different haemoglobin thresholds and area under the receiver operating characteristic curve. Two observers examined a subset of patients (n = 128) to determine the inter-observer agreement, calculated by kappa statistics. We studied 390 patients (mean age 40.1 [SD 17.08] years); of whom 48% were women. The haemoglobin was <7 g/dL in 8% (95% confidence interval, 5, 10) patients; <9 g/dL in 21% (17, 26) patients and <12 g/dL in 64% (60, 70) patients. Among patients with haemoglobin <7 g/dL, presence of severe tongue pallor yielded a LR of 9.87 (2.81, 34.6) and its absence yielded a LR of 0. The tongue pallor outperformed other pallor sites and was also the best discriminator of anaemia at haemoglobin thresholds of 7 g/dL and 9 g/dL (area under the receiver operating characteristic curves (ROC area = 0.84 [0.77, 0.90] and 0.71[0.64, 0.76]) respectively. The agreement between the two observers for detection of anaemia was poor (kappa values = 0.07 for conjunctival pallor and 0.20 for tongue pallor).Conclusions/Significance
Clinical assessment of pallor can rule out and modestly rule in severe anaemia. 相似文献139.
140.
Atherosclerosis and its sequelae are one of the leading causes of morbidity and mortality, especially in the developed nations. Over the years, treatment protocols have changed with the changing understanding of the disease process. Inflammatory mechanisms have emerged as key players in the formation of the atherosclerotic plaque. For the majority of its life span, the plaque develops silently and only some exhibit overt clinical manifestations. The purpose of this review is to examine the inherent properties of some of these "vulnerable" or symptomatic plaques. Rupture of the plaque is related to the thickness of the fibrous cap overlying the necrotic lipid core. A thin cap is more likely to lead to rupture. Multiple factors broadly grouped as the "determinants of vulnerability" are responsible for directly or indirectly influencing the plaque dynamics. Apoptosis is considered an important underlying mechanism that contributes to plaque instability. Inflammatory reactions within the plaque trigger apoptosis by cell-cell contact and intra cellular death signaling. Once started, the apoptotic process affects all of the components that make up the plaque, including vascular smooth muscle cells, endothelial cells, and macrophages. Extensive research has identified many of the key cellular and molecular regulators that play a part in apoptosis within the atherosclerotic lesion. This information will help us to gain a better understanding of the underlying mechanisms at the cellular and molecular level and enable us to formulate better therapeutic strategies to combat this disease. 相似文献