In vitro binding of sterols by extracts from Mucor rouxii cells grown under different environmental conditions

1976 ◽  
Vol 22 (8) ◽  
pp. 1163-1168 ◽  
Author(s):  
S. Safe ◽  
J. Caldwell
Keyword(s):  
Potassium Hydroxide ◽  
Potassium Hydroxide Solution ◽  
Mucor Rouxii ◽  
Growth Environment ◽  
Cell Extracts ◽  
Relative Binding ◽  
Vitro Binding ◽  
Aqueous Potassium Hydroxide ◽  
Aerobic And Anaerobic

Aqueous cell wall and cytoplasm extracts from Mucor rouxii cells grown under aerobic and anaerobic (oxygen-limiting) conditions were obtained. Both of the extracts from the anaerobic and aerobic cells solubilized lanosterol and ergosterol but not to the same extent; ergosterol was complexed about 2–3 times greater than the same concentration of lanosterol. It was also apparent that the relative binding capacities of the cell extracts were dependent on the cell growth environment. Two additional fractions were obtained from each extract by (a) methanol precipitation and (b) refluxing in 2% aqueous potassium hydroxide solution followed by methanol precipitation. The binding activities of these precipitates and the corresponding precipitates from yeast extract were compared and the results indicated a range of binding activites which depended on both the extract and the sterol. The data suggested that the in vitro sterol binding of M. rouxii extracts was not due to one particular macromolecule but that a number of compounds were involved in this complexation process.

Colocalization of chaperone Cpn60, proinsulin and convertase PC1 within immature secretory granules of insulin-secreting cells suggests a role for Cpn60 in insulin processing

2000 ◽  
Vol 113 (11) ◽  
pp. 2075-2083 ◽  
Author(s):  
A.E. Arias ◽  
C.S. Velez-Granell ◽  
G. Mayer ◽  
M. Bendayan
Keyword(s):  
Islet Cell ◽  
Secretory Pathway ◽  
Secretory Granules ◽  
Double Labeling ◽  
In Vitro Binding ◽  
Cell Extracts ◽  
Vitro Binding ◽  
Preferential Binding ◽  
Insulin Secreting Cells

Many of the mechanisms that control insulin processing and packaging by interaction with different elements along the secretory pathway remain poorly understood. We have investigated the possibility that Cpn60, a member of the heat shock protein family, may be present in rat insulin-secreting cells, participating in the proinsulin-insulin maturation process. Immunofluorescence and high resolution immunocytochemical studies revealed the presence of the Cpn60 protein all along the insulin secretory pathway, being particularly abundant over the proinsulin-containing immature secretory granules. Double-labeling experiments showed associations between Cpn60 and proinsulin, as well as between Cpn60 and PC1 convertase, with a preferential binding to proinsulin. These findings paralleled those of coimmunoprecipitation studies showing the Cpn60 chaperone and the mature form of the PC1 convertase in proinsulin immunoprecipitates, as well as the PC1 in Cpn60 immunoprecipitates from total islet cell extracts. In vitro binding of Cpn60 to proinsulin, insulin and glucagon was also documented. Cpn60, significantly abundant in proinsulin-containing secretory granules where conversion of proinsulin to insulin takes place, and the colocalization of the chaperone with proinsulin and PC1 convertase suggest that the Cpn60 protein may play a role directing precise molecular interactions during insulin processing and/or packaging.

Reactions of tert-Butyl Peroxy Esters, XIV. Further Observations on the Preparation of Dialkyl tert-Butylperoxy Phosphates

1975 ◽  
Vol 30 (9-10) ◽  
pp. 732-739 ◽  
Author(s):  
G. Sosnovsky ◽  
E. H. Zaret
Keyword(s):  
Potassium Hydroxide ◽  
Potassium Hydroxide Solution ◽  
Sodium Hydride ◽  
High Yield ◽  
Butyl Hydroperoxide ◽  
Tert Butyl ◽  
Tert Butyl Hydroperoxide ◽  
Aqueous Potassium Hydroxide ◽  
Butyl Peroxide

The preparation of dialkyl tert-butylperoxy phosphates (2, R = alkyl) has been achieved by the reaction of the corresponding dialkyl phosphorochloridates (1, R = alkyl) with tert-butyl hydroperoxide either in the presence of pyridine or in the presence of aqueous potassium hydroxide solution. Neither of these routes is suitable for the preparation of dialkyl tert-butylperoxy phosphates in quantity since they yield peroxyphosphates which are contaminated either with the corresponding tetraalkyl pyrophosphates or dialkyl phosphates; the contaminants cannot easily be removed by conventional means from the peroxyphosphates. The method of choice for the preparation in high yield of large quantities of pure dialkyl tert-butylperoxy phosphates involves the interaction of the corresponding dialkyl phosphorochloridate with sodium tert-butyl peroxide which has been prepared in situ from the reaction of tert-butyl hydroperoxide with sodium hydride.

KINETIC STUDIES OF THE AgO/Ag2O ELECTRODE IN ALKALINE SOLUTIONS

1964 ◽  
Vol 42 (11) ◽  
pp. 2488-2495 ◽  
Author(s):  
R. G. Barradas ◽  
G. H. Fraser
Keyword(s):  
Potassium Hydroxide ◽  
Potassium Hydroxide Solution ◽  
Kinetic Studies ◽  
Alkaline Solutions ◽  
Hyperbolic Function ◽  
Electron Number ◽  
Rate Determining Step ◽  
Symmetry Factor ◽  
Tafel Slopes ◽  
Aqueous Potassium Hydroxide

The anodic oxidation of Ag2O to AgO in normal aqueous potassium hydroxide solution was investigated quantitatively under both galvanostatic and potentiostatic conditions at 25 °C. A few results for similar experiments in N/40 KOH are also reported. Tafel slopes and other parameters were determined. The experimental results show the dependence of current density as a hyperbolic function of overpotential, i.e. i = 2i0 sinh (λFη/2RT). The electron number λ was found to be 2 and the symmetry factor β was confirmed to be 1/2. It is proposed that the rate-determining step for the formation of AgO from Ag2O occurs at the Ag2O/AgO interface and involves the transfer of O−2 ions.

scholarly journals Wet Chemical Etching of AlN Single Crystals

2002 ◽  
Vol 7 ◽  
Author(s):  
D. Zhuang ◽  
J.H. Edgar ◽  
Lianghong Liu ◽  
B. Liu ◽  
L. Walker
Keyword(s):  
Single Crystals ◽  
Basal Plane ◽  
Chemical Etching ◽  
Potassium Hydroxide ◽  
Defect Density ◽  
Potassium Hydroxide Solution ◽  
Aqueous Potassium Hydroxide ◽  
Important Means ◽  
Wet Chemical ◽  
Image Position

Anisotropic chemical etching is an important means for characterizing the polarity and defect density of single crystals. In this letter, we present the results of our studies on the etching of bulk AlN crystals in aqueous potassium hydroxide solution. The nitrogen polarity (0001) basal plane initially etched rapidly, while the aluminum polarity basal plane, and prismatic (100) planes were not etched. The etch rate of the nitrogen polarity basal plane eventually decreased to zero, as the surface became completely covered with hexagonal hillocks which were bounded by {101} planes. The hillock density for the self-seeded AlN crystals studied was typically in the range of 5×107cm−2 to 109cm−2. From our analysis of etched AlN crystals, we infer that freely nucleated crystals predominately have the nitrogen to aluminum direction pointing out from the nucleation surface, that is the ends of the AlN crystals facing the source are aluminum polarity.

Facile and Straightforward Synthesis of Racemic Version of Substituted 3-[3-(2-Hydroxyphenyl)-3-oxo-1-arylpropyl]-4-hydroxycoumarins: Easy Access to a Series of Biorelevant Warfarin Analogues

Synthesis ◽  
2021 ◽  
Author(s):  
Goutam Brahmachari ◽  
Mullicka Mandal ◽  
Indrajit Karmakar
Keyword(s):  
Potassium Hydroxide ◽  
Potassium Hydroxide Solution ◽  
Practical Method ◽  
Easy Access ◽  
Chromatographic Purification ◽  
Present Communication ◽  
Aqueous Potassium Hydroxide ◽  
Hydrolysis Of ◽  
Column Chromatographic ◽  
Operational Simplicity

AbstractThe present communication deals with a straightforward, efficient, and green synthesis of a series of racemic version of 3-[3-(2-hydroxyphenyl)-3-oxo-1-arylpropyl]-4-hydroxycoumarins as biologically interesting warfarin analogues upon decarboxylative hydrolysis of bis-coumarin derivatives in aqueous potassium hydroxide solution. The salient features of this practical method are operational simplicity, avoidance of any organic solvents and tedious column chromatographic purification, clean reaction profiles, excellent yields, and gram-scale synthetic applicability.

scholarly journals Synthesis and Antimicrobial Activity of SomeNovel Benzimidazolyl Chalcones

2009 ◽  
Vol 6 (1) ◽  
pp. 196-200 ◽  
Author(s):  
B. A. Baviskar ◽  
Bhagyesh Baviskar ◽  
M. R. Shiradkar ◽  
U. A. Deokate ◽  
S. S. Khadabadi
Keyword(s):  
Antimicrobial Activity ◽  
Elemental Analysis ◽  
Spectroscopic Data ◽  
Potassium Hydroxide ◽  
Room Temperature ◽  
Potassium Hydroxide Solution ◽  
Aromatic Aldehydes ◽  
Plate Method ◽  
H Nmr ◽  
Aqueous Potassium Hydroxide

Some novel benzimidazolyl chalcones were synthesized by condensation ofN-(4-(1H-benzo[d]imidazol-2-yl)phenyl)acetamide with aromatic aldehydes in presence of aqueous potassium hydroxide solution at room temperature. All the synthesized compounds were characterized on the basis of their IR,1H NMR spectroscopic data and elemental analysis. All the compounds have been screened for antimicrobial activity by the cup-plate method.

scholarly journals Dimerization by Translation Initiation Factor 2 Kinase GCN2 Is Mediated by Interactions in the C-Terminal Ribosome-Binding Region and the Protein Kinase Domain

1998 ◽  
Vol 18 (5) ◽  
pp. 2697-2711 ◽  
Author(s):  
Hongfang Qiu ◽  
Minerva T. Garcia-Barrio ◽  
Alan G. Hinnebusch
Keyword(s):  
Protein Kinase ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Cell Extracts ◽  
Vitro Binding ◽  
Initiation Factor 2 ◽  
Physical Interactions ◽  
Translation Initiation Factor 2 ◽  
Two Hybrid

ABSTRACT The protein kinase GCN2 stimulates translation of the transcriptional activator GCN4 in yeast cells starved for amino acids by phosphorylating translation initiation factor 2. Several regulatory domains, including a pseudokinase domain, a histidyl-tRNA synthetase (HisRS)-related region, and a C-terminal (C-term) segment required for ribosome association, have been identified in GCN2. We used the yeast two-hybrid assay, coimmunoprecipitation analysis, and in vitro binding assays to investigate physical interactions between the different functional domains of GCN2. A segment containing about two thirds of the protein kinase (PK) catalytic domain and another containing the C-term region of GCN2 interacted with themselves in the two-hybrid assay, and both the PK and the C-term domains could be coimmunoprecipitated with wild-type GCN2 from yeast cell extracts. In addition, in vitro-translated PK and C-term segments showed specific binding in vitro to recombinant glutathioneS-transferase (GST)–PK and GST–C-term fusion proteins, respectively. Wild-type GCN2 could be coimmunoprecipitated with a full-length LexA-GCN2 fusion protein from cell extracts, providing direct evidence for dimerization by full-length GCN2 molecules. Deleting the C-term or PK segments abolished or reduced, respectively, the yield of GCN2–LexA-GCN2 complexes. These results provide in vivo and in vitro evidence that GCN2 dimerizes through self-interactions involving the C-term and PK domains. The PK domain showed pairwise in vitro binding interactions with the pseudokinase, HisRS, and C-term domains; additionally, the HisRS domain interacted with the C-term region. We propose that physical interactions between the PK domain and its flanking regulatory regions and dimerization through the PK and C-term domains both play important roles in restricting GCN2 kinase activity to amino acid-starved cells.

scholarly journals Synthesis, Characterization and Antimicrobial Activity Study of Some New Substituted Benzoxazole Derivatives

2019 ◽  
Vol 16 (3) ◽  
pp. 616
Author(s):  
Nuaman Alheety
Keyword(s):  
Potassium Hydroxide ◽  
Potassium Hydroxide Solution ◽  
Chloroacetic Acid ◽  
Proton Nuclear Magnetic Resonance ◽  
Antibacterial Drug ◽  
Inhibition Effect ◽  
Alcoholic Potassium Hydroxide ◽  
Physico Chemical ◽  
In Vitro Antibacterial Activity

This research included the preparation of 2-mercaptobenzoxazole (N1) by the reaction of ortho-aminophenol with carbon disulfide in an alcoholic potassium hydroxide solution. The 2-mercapto benzoxazole (N1) was then treated with hydrazine to obtain the 2-hydrazino benzoxazole (N2). A number of hydrazones (N3-N5) were prepared through the reaction of N2 with different benzaldehydes. The compound (N6) was also prepared whereby the ring closing of hydrazone (N3) using chloroacetylchloride, while the compound (N7) was prepared by treating 2-hydrazino benzoxazole with acetylacetone. When the compound (N1) was treated with formaldehyde, it afforded the compound (N8). Also, the N9 was obtained from the reaction of N1 with chloroacetic acid in the presence of alcoholic potassium hydroxide. The prepared compounds were characterized using physico-chemical and spectroscopic methods such as melting point, infrared spectroscopy (IR) and the proton nuclear magnetic resonance (1H-NMR). Thereafter, some of the compounds were selected for in vitro antibacterial activity and one of these compounds showed an inhibition effect against gram positive only which is very important because it is considered as specific antibacterial drug.

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