scholarly journals Degradation of Millimolar Concentration of the Herbicide Dalapon (2,2-Dichloropropionic Acid) byRhizobiumSp. Isolated from Soil

2012 ◽  
Vol 26 (4) ◽  
pp. 3106-3112 ◽  
Author(s):  
Fahrul Huyop ◽  
Ronald Cooper
Keyword(s):  
Millimolar Concentration

scholarly journals Study of the coordination of quinuclidine to a chiral zinc phthalocyanine dimer

2016 ◽  
Vol 20 (08n11) ◽  
pp. 1224-1232 ◽  
Author(s):  
Nelson Giménez-Agulló ◽  
Gemma Aragay ◽  
José Ramón Galán-Mascarós ◽  
Pablo Ballester
Keyword(s):  
Chemical Exchange ◽  
Variable Temperature ◽  
Exchange Process ◽  
Zinc Phthalocyanine ◽  
Hydrogen Atoms ◽  
Dimerization Constant ◽  
H Nmr ◽  
Dimerization Process ◽  
Nmr Titrations ◽  
Millimolar Concentration

We attempted the calculation of an accurate equilibrium constant for the dimerization process of enantiomerically pure Zn-1 using UV-vis dilution experiments. At millimolar concentration Zn-1 is involved in a chemical exchange process between its monomeric and dimeric state that is slow on the 1H NMR timescale. We performed variable-temperature 1H NMR experiments in CDCl3 solution to determine the dimerization constant value at different temperatures and performed a van’t Hoff plot to derive the thermodynamic parameters of the process. The calculated thermodynamic data revealed that the dimerization process is entropy-driven and enthalpically opposed. We also probed the coordination of quinuclidine, 1-azabicyclo[2.2.2]octane, 2, to the Zn-1 using UV-vis and 1H NMR titrations in CDCl3 solution. At micromolar concentration the Zn-1 exclusively exists in solution as a monomer and forms a simple 1:1, [Formula: see text], complex with quinuclidine having a stability constant of [Formula: see text]([Formula: see text]) [Formula: see text] 106 M[Formula: see text]. On the other hand, the 1H NMR titrations carried out at 298 K and at millimolar concentration showed that Zn-1 was present in solution as the dimer and formed 1:2, [Formula: see text], and 2:2, [Formula: see text] complexes by coordination to 2. In addition, the 1:1 complex, [Formula: see text] showed a reduced dimerization constant compared to the uncoordinated parent monomer Zn-1. At high quinuclidine concentration, the 1:1 complex, [Formula: see text], derived from the coordinated dimer dissociation was also detected. The 1H NMR spectra of the titrations displayed separate signals for some hydrogen atoms of the Zn-phthalocyanine in each one of the four species. Remarkably, the chemical exchange processes involving free and bound quinuclidine in the monomeric and dimeric complexes showed different kinetics on the NMR timescale.

Divalent cation stimulation of in vitro fibre assembly from epidermal keratin protein

1978 ◽  
Vol 33 (1) ◽  
pp. 255-263
Author(s):  
K. Fukuyama ◽  
T. Murozuka ◽  
R. Caldwell ◽  
W.L. Epstein
Keyword(s):  
Ionic Strength ◽  
Divalent Cation ◽  
Divalent Cations ◽  
Urea Concentration ◽  
Newborn Rats ◽  
Filament Formation ◽  
Stimulation Of ◽  
Millimolar Concentration

Keratin was extracted from purified cornified cells of newborn rats in Tris-HCl-buffered 8 M urea containing beta-mercaptoethanol. Microfilaments were assembled in vitro by reducing the ionic strength of buffer and the urea concentration. One millimolar concentration of KCl and NaCl did not affect filament formation, but the same concentration of divalent cations greatly altered this process. CaCl2 and MgCl2 induced gelation of keratin by formation of bundles of birefringent macrofilaments. ZnCl2, CuSO4 and HgCl2 formed greater numbers of macrofilaments and the protein aggregated.

Distribution of actin filament lengths measured by fluorescence microscopy

1992 ◽  
Vol 262 (3) ◽  
pp. C569-C577 ◽  
Author(s):  
S. Burlacu ◽  
P. A. Janmey ◽  
J. Borejdo
Keyword(s):  
Sample Preparation ◽  
Correlation Length ◽  
Actin Filament ◽  
Actin Filaments ◽  
Average Length ◽  
Potassium Acetate ◽  
Tetramethylrhodamine Isothiocyanate ◽  
Good Agreement ◽  
Millimolar Concentration

We analyzed the distribution of actin filament lengths by optical microscopy (OM). OM avoids possible alterations in the size or structure of actin filaments occurring during sample preparation for electron microscopy (EM). Images of F-actin labeled with tetramethylrhodamine isothiocyanate (TRITC)-phalloidin were analyzed for both size distribution and flexibility. In the standard buffer [25 mM potassium acetate, 4 mM MgSO4, 25 mM tris(hydroxymethyl)aminomethane acetate, pH 7.5, 20 mM beta-mercaptoethanol] filaments did not aggregate into bundles and remained stable at nanomolar concentrations for at least 1 h. At the same concentration, actin labeled directly with rhodamine (no phalloidin) formed unstable filaments whose average length decreased with time. The number average length of TRITC-phalloidin labeled filaments (Ln) was 4.90 microns, the ratio (rho) of the weight average length to the number average length was 2.06, and the correlation length (1/lambda) was 8.33 microns. These parameters were in good agreement with the values determined by EM for filaments shorter than 8 microns. Passing G-actin through a Sephadex G-150 column before polymerization did not have a significant effect on the distribution of lengths but made filaments more stiff (1/lambda = 12.5 microns). Millimolar concentration of ATP increased the correlation length, and gelsolin had the expected fragmenting effect on filaments. These results show that OM can be used as a fast and reliable method to analyze the distribution and flexibility of actin filaments and suggest that, in spite of extensive manipulation of actin filaments during sample preparation, EM is a valid tool for determination of size parameters of actin filaments.

Molecular dynamics approach to understand the denaturing effect of a millimolar concentration of dodine on a λ-repressor and counteraction by trehalose

2017 ◽  
Vol 19 (20) ◽  
pp. 13160-13171 ◽  
Author(s):  
Gargi Borgohain ◽  
Bikramaditya Mandal ◽  
Sandip Paul
Keyword(s):  
Molecular Dynamics ◽  
Distribution Function ◽  
Spatial Distribution ◽  
Spatial Distribution Function ◽  
System P ◽  
Millimolar Concentration

Here, we use a molecular dynamics approach to calculate the spatial distribution function of the ternary water–dodine–trehalose (1.0 M) system.

scholarly journals Direct deamination of AMP, ADP, ATP and NADH by non-specific adenylate deaminase in the foot muscle of the snail Helix pomatia

1983 ◽  
Vol 215 (1) ◽  
pp. 39-44 ◽  
Author(s):  
A J Stankiewicz
Keyword(s):  
Helix Pomatia ◽  
Analytical Tool ◽  
Fresh Tissue ◽  
High Affinity ◽  
Adenylate Deaminase ◽  
Snail Enzyme ◽  
Snail Helix Pomatia ◽  
Species Specific ◽  
Very High ◽  
Millimolar Concentration

Homogeneous adenylate deaminase from snail foot muscle deaminated 5′-AMP, 5′-ADP, 5′-ATP and NADH with similar velocity and affinity to all substrates. At millimolar concentration NAD+ was also deaminated to a comparable extent, but NADP+, NADPH and FAD were not substrates for the snail enzyme. The amount of deaminase activity per g of fresh tissue is 5-10 times greater than in the muscle of any other species studied. The activity of the snail deaminase is regulated by pH, KCl and buffer concentrations, and Pi; however, regulation seems to be very poor in comparison with that of muscle deaminases from other species, specific to 5′-AMP. Snail enzyme appears as the first animal deaminase so far described that has such characteristics. It offers also some opportunities as an analytical tool as a consequence of its very high affinity toward adenylates.

Differentiation between Plasminogen Activators by Means of Epsilon- Aminocaproic Acid

1972 ◽  
Vol 27 (01) ◽  
pp. 077-087 ◽  
Author(s):  
P Kok ◽  
T Astrup
Keyword(s):  
Plasminogen Activator ◽  
Human Urine ◽  
Aminocaproic Acid ◽  
Plasminogen Activators ◽  
Uterine Tissue ◽  
Biphasic Pattern ◽  
Fibrin Plate ◽  
Epsilon Aminocaproic Acid ◽  
Millimolar Concentration

SummaryThe differentiation between plasminogen activators from tissue and urine by means of the patterns of inhibition produced by epsilon-aminocaproic acid (EACA) in fibrin plate assays was investigated. Different inhibition patterns reflected genuine differences between two types of activators. The method allows the differentiation between two types of activators in weakly fibrinolytic and impure activator solutions.A biphasic pattern of inhibition by EACA was observed with human urine as well as with the purified urokinase preparations. The degree of enhancement of fibrinolysis observed in the millimolar concentration range of EACA fluctuated with the fibrin substrate and was, in part, related to its plasminogen content. Increasing concentrations of EACA produced a uniformly increasing inhibition of preparations of tissue activator obtained in various degrees of purity from porcine ovary and heart. Plasmin was uniformly inhibited by EACA. Inhibition of plasmin required about 100 times higher concentrations of EACA than inhibition of tissue activator-induced fibrinolysis. EACA produced a slightly biphasic pattern of inhibition with plasminogen activator from human uterine tissue.

Recovery of milligrams of products in acetic acid at millimolar concentration via solvent extraction

Talanta ◽  
1966 ◽  
Vol 13 (2) ◽  
pp. 318-321
Author(s):  
Robert E. Aufuldish Jr. ◽  
Kenneth G. Stone ◽  
Henry C. Yu
Keyword(s):  
Acetic Acid ◽  
Solvent Extraction ◽  
Millimolar Concentration
Sign in / Sign up

Export Citation Format

Share Document