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https://www.readbyqxmd.com/read/27647541/a-randomized-double-blind-placebo-controlled-study-of-efficacy-and-tolerability-of-withaina-somnifera-extracts-in-knee-joint-pain
#1
G S H Ramakanth, C Uday Kumar, P V Kishan, P Usharani
BACKGROUND: Root extracts of Withania somnifera (Ashwagandha) are known to possess analgesic, anti-inflammatory and chondroprotective effects. An aqueous extract of roots plus leaves of this plant has shown to yield higher percentages of withanolide glycosides and, accordingly, may possess better analgesic, anti-inflammatory and chondroprotective effects than root alone extracts. OBJECTIVES: To evaluate efficacy and tolerability of a standardized aqueous extract of roots plus leaves of W...
July 2016: Journal of Ayurveda and Integrative Medicine
https://www.readbyqxmd.com/read/27545569/a-critical-test-of-the-electrostatic-contribution-to-catalysis-with-noncanonical-amino-acids-in-ketosteroid-isomerase
#2
Yufan Wu, Steven G Boxer
The vibrational Stark effect (VSE) has been used to measure the electric field in the active site of ketosteroid isomerase (KSI). These measured fields correlate with ΔG(⧧) in a series of conventional mutants, yielding an estimate for the electrostatic contribution to catalysis (Fried et al. Science 2014, 346, 1510-1513). In this work we test this result with much more conservative variants in which individual Tyr residues in the active site are replaced by 3-chlorotyrosine via amber suppression. The electric fields sensed at the position of the carbonyl bond involved in charge displacement during catalysis were characterized using the VSE, where the field sensitivity has been calibrated by vibrational Stark spectroscopy, solvatochromism, and MD simulations...
September 14, 2016: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/27541577/vibrational-stark-effects-of-carbonyl-probes-applied-to-reinterpret-ir-and-raman-data-for-enzyme-inhibitors-in-terms-of-electric-fields-at-the-active-site
#3
Samuel H Schneider, Steven G Boxer
IR and Raman frequency shifts have been reported for numerous probes of enzyme transition states, leading to diverse interpretations. In the case of the model enzyme ketosteroid isomerase (KSI), we have argued that IR spectral shifts for a carbonyl probe at the active site can provide a connection between the active site electric field and the activation free energy (Fried et al. Science 2014, 346, 1510-1514). Here we generalize this approach to a much broader set of carbonyl probes (e.g., oxoesters, thioesters, and amides), first establishing the sensitivity of each probe to an electric field using vibrational Stark spectroscopy, vibrational solvatochromism, and MD simulations, and then applying these results to reinterpret data already in the literature for enzymes such as 4-chlorobenzoyl-CoA dehalogenase and serine proteases...
September 15, 2016: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/27410422/evaluation-of-the-catalytic-contribution-from-a-positioned-general-base-in-ketosteroid-isomerase
#4
Vandana Lamba, Filip Yabukarski, Margaux Pinney, Daniel Herschlag
Proton transfer reactions are ubiquitous in enzymes and utilize active site residues as general acids and bases. Crystal structures and site-directed mutagenesis are routinely used to identify these residues, but assessment of their catalytic contribution remains a major challenge. In principle, effective molarity measurements, in which exogenous acids/bases rescue the reaction in mutants lacking these residues, can estimate these catalytic contributions. However, these exogenous moieties can be restricted in reactivity by steric hindrance or enhanced by binding interactions with nearby residues, thereby resulting in over- or underestimation of the catalytic contribution, respectively...
August 10, 2016: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/27375051/role-of-conserved-met112-residue-in-the-catalytic-activity-and-stability-of-ketosteroid-isomerase
#5
Hyung Jin Cha, Do Soo Jang, Jae-Hee Jeong, Bee Hak Hong, Young Sung Yun, Eun Ju Shin, Kwan Yong Choi
Ketosteroid isomerase (3-oxosteroid Δ(5)-Δ(4)-isomerase, KSI) from Pseudomonas putida catalyzes allylic rearrangement of the 5,6-double bond of Δ(5)-3-ketosteroid to 4,5-position by stereospecific intramolecular transfer of a proton. The active site of KSI is formed by several hydrophobic residues and three catalytic residues (Tyr14, Asp38, and Asp99). In this study, we investigated the role of a hydrophobic Met112 residue near the active site in the catalysis, steroid binding, and stability of KSI. Replacing Met112 with alanine (yields M112A) or leucine (M112L) decreased the kcat by 20- and 4-fold, respectively...
October 2016: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/26992790/enhanced-bioconversion-rate-and-released-substrate-inhibition-in-r-phenylephrine-whole-cell-bioconversion-via-partial-acetone-treatment
#6
Shu-Chen Kan, Chi-Zong Zang, Chiung-Wen Yeh, Wei-Feng Chang, Chia-Chi Lin, Tzu-Hsiang Hung, Chwen-Jen Shieh, Yung-Chuan Liu
An approach was developed to enhance the efficiency for the bioconversion of 1-(3-hydroxyphenyl)-2-(methyamino)-ethanone to (R)-phenylephrine. The strain Serratia marcescens N10612, giving the benefit of 99% enantiomeric excess in (R)-PE conversion, was used. The fermentation was devised to harvest cells with high hydrophobic prodigiosin content inside the cells. Then, the partial acetone extraction was applied to remove prodigiosin from the cells. The treatment was found to increase the cells conversion rate without loss of the cells NADPH redox system...
May 2016: Enzyme and Microbial Technology
https://www.readbyqxmd.com/read/26788959/how-would-increasing-seat-belt-use-affect-the-number-of-killed-or-seriously-injured-light-vehicle-occupants
#7
Alena Høye
The expected effects of increasing seat belt use on the number of killed or seriously injured (KSI) light vehicle occupants have been estimated for three scenarios of increased seat belt use in Norway, taking into account current seat belt use, the effects of seat belts and differences in crash risk between belted and unbelted drivers. The effects of seat belts on fatality and injury risk were investigated in a meta-analysis that is based on 24 studies from 2000 or later. The results indicate that seat belts reduce both fatal and non-fatal injuries by 60% among front seat occupants and by 44% among rear seat occupants...
March 2016: Accident; Analysis and Prevention
https://www.readbyqxmd.com/read/26571340/dissecting-proton-delocalization-in-an-enzyme-s-hydrogen-bond-network-with-unnatural-amino-acids
#8
Yufan Wu, Stephen D Fried, Steven G Boxer
Extended hydrogen bond networks are a common structural motif of enzymes. A recent analysis proposed quantum delocalization of protons as a feature present in the hydrogen bond network spanning a triad of tyrosines (Y(16), Y(32), and Y(57)) in the active site of ketosteroid isomerase (KSI), contributing to its unusual acidity and large isotope shift. In this study, we utilized amber suppression to substitute each tyrosine residue with 3-chlorotyrosine to test the delocalization model and the proton affinity balance in the triad...
December 8, 2015: Biochemistry
https://www.readbyqxmd.com/read/26565127/electrochemical-imaging-and-redox-interrogation-of-surface-defects-on-operating-srtio3-photoelectrodes
#9
Burton H Simpson, Joaquín Rodríguez-López
We introduce electrochemical imaging and nano-resolved measurements of catalytic intermediates on operating SrTiO3 photoelectrodes. Spatially resolved redox titrations of photogenerated reactive oxygen species (ROS) were used to profile changes in ROS coverage and reactivity at pristine and ion-milled defective areas on n-doped (100) SrTiO3. Adsorbed ROS reached a potential-dependent limiting coverage of ∼0.1 monolayer and did not differ significantly between milled and pristine areas. However, the reaction kinetics between a solution-phase mediator and adsorbed ROS were found to be significantly decreased over ion-milled areas...
December 2, 2015: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/26558202/presence-of-fleischer-ring-and-prominent-corneal-nerves-in-keratoconus-relatives-and-normal-controls
#10
Ágnes Kriszt, Gergely Losonczy, András Berta, Lili Takács
AIM: To examine the occurrence of commonly known clinical signs of keratoconus (KC), i.e. Fleischer ring, prominent corneal nerves and thinning, among unaffected family members of KC patients and healthy control individuals. METHODS: Data of both eyes of 117 relatives of KC patients having no manifest disease based on videokeratography indices (KC relatives), and 142 controls were used for Pearson correlation and t-test statistics. Correlation of Fleischer ring, prominent corneal nerves and central pachymetry data were tested with each other and with videokeratography indices (KSI, KISA, 3 and 6 mm Fourier asymmetry, and I-S)...
2015: International Journal of Ophthalmology
https://www.readbyqxmd.com/read/26526133/field-application-of-safe-chemical-elicitors-induced-the-expression-of-some-resistance-genes-against-grey-mold-and-cottony-rot-diseases-during-snap-bean-pods-storage
#11
Hoda A S El-Garhy, Ismail A S Rashid, Rania M Abou-Ali, Mahmoud M A Moustafa
Phaseolus vulgaris is subjected to serious post-harvest diseases such as grey mold and cottony rot diseases caused by Botrytis cinerea and Pythium aphanidermatum, respectively. In current study, potassium silicate (KSi), potassium thiosulfate (KTS) and potassium sulfate (KS) suppressed moderately the growth of B. cinerea and P. aphanidermatum in vitro. The applied treatments significantly suppressed grey mold and cottony rot of Xera and Valentino snap beans varieties' pods stored at 7 ± 1°C and 90-95% RH for 20 days...
January 15, 2016: Gene
https://www.readbyqxmd.com/read/26429409/metabolism-of-kurarinone-by-human-liver-microsomes-and-its-effect-on-cytotoxicity
#12
Xiuwen Zhang, Peng Jiang, Ping Chen, Nengneng Cheng
CONTEXT: Kurarinone, the most abundant prenylated flavonoid in Sophora flavescens Aiton (Leguminosae), is a promising antitumor therapeutic. However, it shows significant hepatotoxicity. Furthermore, how kurarinone is metabolized in humans remains unclear. OBJECTIVE: The objective of this study is to investigate kurarinone metabolism in human liver microsomes (HLMs) and the role of metabolism in kurarinone-induced cytotoxicity. MATERIALS AND METHODS: The UDP-glucuronosyltransferase isoforms (UGTs) involved in kurarinone glucuronidation were identified using chemical inhibitors (100-1000 µM phenylbutazone; 10-100 µM β-estradiol; 10-100 µM 1-naphthol; 10-500 µM propofol; and 100-1000 µM fluconazole) and recombinant human UGTs...
2016: Pharmaceutical Biology
https://www.readbyqxmd.com/read/26315428/biophysics-response-to-comments-on-extreme-electric-fields-power-catalysis-in-the-active-site-of-ketosteroid-isomerase
#13
COMMENT
Stephen D Fried, Steven G Boxer
Natarajan et al. and Chen and Savidge comment that comparing the electric field in ketosteroid isomerase's (KSI's) active site to zero overestimates the catalytic effect of KSI's electric field because the reference reaction occurs in water, which itself exerts a sizable electrostatic field. To compensate, Natarajan et al. argue that additional catalytic weight arises from positioning of the general base, whereas Chen and Savidge propose a separate contribution from desolvation of the general base. We note that the former claim is not well supported by published results, and the latter claim is intriguing but lacks experimental basis...
August 28, 2015: Science
https://www.readbyqxmd.com/read/26239185/multidrug-resistance-associated-protein-4-mrp4-abcc4-controls-efflux-transport-of-hesperetin-sulfates-in-sulfotransferase-1a3-overexpressing-human-embryonic-kidney-293-cells
#14
Hua Sun, Xiao Wang, Xiaotong Zhou, Danyi Lu, Zhiguo Ma, Baojian Wu
Sulfonation is an important metabolic pathway for hesperetin. However, the mechanisms for the cellular disposition of hesperetin and its sulfate metabolites are not fully established. In this study, disposition of hesperetin via the sulfonation pathway was investigated using human embryonic kidney (HEK) 293 cells overexpressing sulfotransferase 1A3. Two monosulfates, hesperetin-3'-O-sulfate (H-3'-S) and hesperetin-7-O-sulfate (H-7-S), were rapidly generated and excreted into the extracellular compartment upon incubation of the cells with hesperetin...
October 2015: Drug Metabolism and Disposition: the Biological Fate of Chemicals
https://www.readbyqxmd.com/read/26225832/cooperativity-in-cyp2e1-metabolism-of-acetaminophen-and-styrene-mixtures
#15
Jessica H Hartman, Lynda G Letzig, Dean W Roberts, Laura P James, E Kim Fifer, Grover P Miller
Risk assessment for exposure to mixtures of drugs and pollutants relies heavily on in vitro characterization of their bioactivation and/or metabolism individually and extrapolation to mixtures assuming no interaction. Herein, we demonstrated that in vitro CYP2E1 metabolic activation of acetaminophen and styrene mixtures could not be explained through the Michaelis-Menten mechanism or any models relying on that premise. As a baseline for mixture studies with styrene, steady-state analysis of acetaminophen oxidation revealed a biphasic kinetic profile that was best described by negative cooperativity (Hill coefficient=0...
October 1, 2015: Biochemical Pharmacology
https://www.readbyqxmd.com/read/26126183/safety-effects-of-fixed-speed-cameras-an-empirical-bayes-evaluation
#16
Alena Høye
The safety effects of 223 fixed speed cameras that were installed between 2000 and 2010 in Norway were investigated in a before-after empirical Bayes study with control for regression to the mean (RTM). Effects of trend, volumes, and speed limit changes are controlled for as well. On road sections between 100m upstream and 1km downstream of the speed cameras a statistically significant reduction of the number of injury crashes by 22% was found. For killed and severely injured (KSI) and on longer road sections none of the results are statistically significant...
September 2015: Accident; Analysis and Prevention
https://www.readbyqxmd.com/read/26066637/decreased-expression-of-multidrug-resistance-associated-protein-4-mrp4-abcc4-leads-to-reduced-glucuronidation-of-flavonoids-in-ugt1a1-overexpressing-hela-cells-the-role-of-futile-recycling
#17
Hua Sun, Xiaotong Zhou, Xingwang Zhang, Baojian Wu
In this study, the role of futile recycling (or deglucuronidation) in the disposition of two flavonoids (i.e., genistein and apigenin) was explored using UGT1A1-overexpressing HeLa cells (or HeLa1A1 cells). Glucuronidation of the flavonoids by HeLa1A1 cell lysate followed the substrate inhibition kinetics (Vmax = 0.10 nmol/min/mg, Km = 0.54 μM, and Ksi = 2.0 μM for genistein; Vmax = 0.19 nmol/min/mg, Km = 0.56 μM, and Ksi = 3.7 μM for apigenin). Glucuronide was efficiently generated and excreted after incubation of the cells with the aglycone (at doses of 1...
July 8, 2015: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/25947291/contribution-of-a-low-barrier-hydrogen-bond-to-catalysis-is-not-significant-in-ketosteroid-isomerase
#18
Do Soo Jang, Gildon Choi, Hyung Jin Cha, Sejeong Shin, Bee Hak Hong, Hyeong Ju Lee, Hee Cheon Lee, Kwan Yong Choi
Low-barrier hydrogen bonds (LBHBs) have been proposed to have important influences on the enormous reaction rate increases achieved by many enzymes. Δ(5)-3-ketosteroid isomerase (KSI) catalyzes the allylic isomerization of Δ(5)-3-ketosteroid to its conjugated Δ(4)-isomers at a rate that approaches the diffusion limit. Tyr14, a catalytic residue of KSI, has been hypothesized to form an LBHB with the oxyanion of a dienolate steroid intermediate generated during the catalysis. The unusual chemical shift of a proton at 16...
May 2015: Molecules and Cells
https://www.readbyqxmd.com/read/25756230/open-shell-lanthanide-ii-or-iii-complexes-bearing-%C3%AF-silyl-and-silylene-ligands-synthesis-structure-and-bonding-analysis
#19
Rainer Zitz, Henning Arp, Johann Hlina, Małgorzata Walewska, Christoph Marschner, Tibor Szilvási, Burgert Blom, Judith Baumgartner
Complexes featuring lanthanide (Ln)-Si bonds represent a highly neglected research area. Herein, we report a series of open-shell Ln(II+) and Ln(III+) complexes bearing σ-bonded silyl and base-stabilized N-heterocyclic silylene (NHSi) ligands. The reactions of the Ln(III+) complexes Cp3Ln (Ln = Tm, Ho, Tb, Gd; Cp = cyclopentadienide) with the 18-crown-6 (18-cr-6)-stabilized 1,4-oligosilanyl dianion [(18-cr-6)KSi(SiMe3)2SiMe2SiMe2Si(SiMe3)2K(18-cr-6)] (1) selectively afford the corresponding metallacyclopentasilane salts [Cp2Ln({Si(SiMe3)2SiMe2}2)](-)[K2(18-cr-6)2Cp](+) [Ln = Tm (2a), Ho (2b), Tb (2c), Gd (2d)]...
April 6, 2015: Inorganic Chemistry
https://www.readbyqxmd.com/read/25691009/ultrasound-assisted-r-phenylephrine-whole-cell-bioconversion-by-s-marcescens-n10612
#20
Chi-Zong Zang, Shu-Chen Kan, Chiung-Wen Yeh, Chia-Chi Lin, Chwen-Jen Shieh, Yung-Chuan Liu
The strain Serratia marcescens N10612 is used to perform the bioconversion of 1-(3-hydroxyphenyl)-2-(methyamino)-ethanone (HPMAE) to (R)-phenylephrine ((R)-PE), which is an ephedrine drug substitute. The use of an ultrasound approach is found to improve the efficiency of the (R)-PE bioconversion. The optimization of the (R)-PE bioconversion is carried out by means of statistical experiment design. The optimal conditions obtained are 1.0mM HPMAE, 18.68 g/L glucose and ultrasound power of 120 W, where the predicted specific rate of the (R)-PE bioconversion is 31...
September 2015: Ultrasonics Sonochemistry
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