Phosphatidic acid regulates the activity of the channel-forming ionophores alamethicin, melittin, and nystatin: A1H-NMR study using phospholipid membranes

1984 ◽  
Vol 4 (5) ◽  
pp. 403-413 ◽  
Author(s):  
G. R. A. Hunt ◽  
I. C. Jones ◽  
J. A. Veiro
Keyword(s):  
Nmr Spectroscopy ◽  
Phosphatidic Acid ◽  
Active Metabolite ◽  
Egg Yolk ◽  
Phospholipid Vesicles ◽  
Dipalmitoyl Phosphatidylcholine ◽  
Egg Yolk Phosphatidylcholine ◽  
Nmr Study ◽  
The Individual ◽  
Egg Pc

The regulation of ion channels by phosphatidic acid (a proposed active metabolite in the phosphatidylinositol effect) was investigated using1H-NMR spectroscopy and small unilamellar phospholipid vesicles. Transport across egg-yolk phosphatidylcholine (egg PC) and dipalmitoyl phosphatidylcholine (DPPC) vesicular membranes in the presence of the channel-forming ionophores alamethicin, melittin, and nystatin was monitored using the lanthanide probe ion Pr3+. In the absence of the ionophores, phosphatidic acid (PA) alone was found to have no ionophore properties, but in the presence of the ionophores the incorporation of 3 mol % phosphatidic acid in the bilayer markedly increased the rate of transport using melittin and nystatin, but decreased the rate using alamethicin, independent of the type of phosphatidylcholine used. The presence of PA in the bilayer also stimulated the production of lyric type channels, the extent of which were both ionophore- and lipid-dependent. These results are discussed in terms of possible molecular interactions between the PA, the individual ionophores, and type of lipid used.

Acyl specificity of CDPcholine:l,2-diacylglycerol cholinephosphotransferase in rat lung

1977 ◽  
Vol 55 (6) ◽  
pp. 609-617 ◽  
Author(s):  
F. Possmayer ◽  
G. Duwe ◽  
M. Hahn ◽  
D. Buchnea
Keyword(s):  
Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
De Novo ◽  
Saturated Fatty Acids ◽  
Fetal Lung ◽  
Egg Yolk ◽  
Rat Lung ◽  
Microsomal Preparation ◽  
Dipalmitoyl Phosphatidylcholine ◽  
Egg Yolk Phosphatidylcholine

Under optimal conditions, rat lung microsomal cholinephosphotransferase (EC 2.7.8.2) activity is markedly stimulated by exogenously added 1,2-sn-diacylglycerols containing an unsaturated fatty acid at the 2-position. Diacylglycerols containing long-chain saturated fatty acids at the 1- and 2-positions did not stimulate the incorporation of CDP[14C]choline above the incorporation observed with the endogenous diacylglycerols present in the microsomal preparation. 1-Oleoyl,2-palmitoyl-sn-glycerol was also ineffective in stimulating phosphatidylcholine synthesis. Diacylglycerols containing linoleate or linolenate at the 2-position were not as effective as 1-palmitoyl,2-oleoyl-sn-glycerol. Identical stimulations were observed with the latter diacylglycerol and 'natural' diacylglycerols prepared from egg-yolk phosphatidylcholine or pig liver phosphatidylcholine. Marked selectivities were observed with diacylglycerols containing two unsaturated fatty acids. Only minor amounts of 1,2-[14C]dipalmitoyl-sn-glycerol were incorporated into phosphatidylcholine, even when this radioactive diacylglycerol was dispersed with 'egg' diacylglycerols. When CDP[14C]choline was incorporated into rat lung microsomal lipids with endogenous diacylglycerols or diacylglycerols endogenously generated by phospholipase C (EC 3.1.4.3) (Bacillus cereus), little radioactivity was associated with the disaturated species of phosphatidylcholine.It has previously been suggested that cholinephosphotransferase catalyses the rate-limiting reaction in the biosynthesis of phosphatidylcholine by lung and that this enzyme is specifically induced in fetal lung by glucocorticoids. The present results indicate that these proposals are untenable and must be reevaluated. These experiments also suggest that dipalmitoyl phosphatidylcholine is not synthesized readily by the de novo pathway for lecithin synthesis and must be produced through reacylation or transesterification mechanisms.

scholarly journals Sphingomyelin exhibits greatly enhanced protection compared with egg yolk phosphatidylcholine against detergent bile salts

2000 ◽  
Vol 41 (6) ◽  
pp. 916-924 ◽  
Author(s):  
Antonio Moschetta ◽  
Gerard P. vanBerge-Henegouwen ◽  
Piero Portincasa ◽  
Giuseppe Palasciano ◽  
Albert K. Groen ◽  
...  
Keyword(s):  
Bile Salts ◽  
Egg Yolk ◽  
Egg Yolk Phosphatidylcholine

scholarly journals Resolving Entangled JH-H-Coupling Patterns for Steroidal Structure Determinations by NMR Spectroscopy

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2643
Author(s):  
Danni Wu ◽  
Kathleen Joyce Carillo ◽  
Jiun-Jie Shie ◽  
Steve S.-F. Yu ◽  
Der-Lii M. Tzou
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr Spectroscopy ◽  
Chemical Shifts ◽  
Atomic Level ◽  
Molecular Structures ◽  
Naturally Occurring ◽  
Structure Determinations ◽  
Ligand Interactions ◽  
Synthetic Steroids ◽  
The Individual

For decades, high-resolution 1H NMR spectroscopy has been routinely utilized to analyze both naturally occurring steroid hormones and synthetic steroids, which play important roles in regulating physiological functions in humans. Because the 1H signals are inevitably superimposed and entangled with various JH–H splitting patterns, such that the individual 1H chemical shift and associated JH–H coupling identities are hardly resolved. Given this, applications of thess information for elucidating steroidal molecular structures and steroid/ligand interactions at the atomic level were largely restricted. To overcome, we devoted to unraveling the entangled JH–H splitting patterns of two similar steroidal compounds having fully unsaturated protons, i.e., androstanolone and epiandrosterone (denoted as 1 and 2, respectively), in which only hydroxyl and ketone substituents attached to C3 and C17 were interchanged. Here we demonstrated that the JH–H values deduced from 1 and 2 are universal and applicable to other steroids, such as testosterone, 3β, 21-dihydroxygregna-5-en-20-one, prednisolone, and estradiol. On the other hand, the 1H chemical shifts may deviate substantially from sample to sample. In this communication, we propose a simple but novel scheme for resolving the complicate JH–H splitting patterns and 1H chemical shifts, aiming for steroidal structure determinations.

scholarly journals Tautomerisation in 1-(4-Methylphenylazo)naphthalen-2-ol and 2-(4-Methylphenylazo)-4-methylphenol: A Crystallographic and 13C{1H}NMR Study

1999 ◽  
Vol 23 (3) ◽  
pp. 178-179
Author(s):  
Wendy I. Cross ◽  
Kevin R. Flower ◽  
Robin G. Pritchard
Keyword(s):  
Acetic Acid ◽  
Nmr Spectroscopy ◽  
Resonant Frequency ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Nmr Study ◽  
Acetic Acid Esters ◽  
Acid Esters ◽  
Equivalent Carbon

The acetic acid esters of 1-(4-methylphenylazo)naphthalen-2-ol 1 and 2-(4-methylphenylazo)-4-methylphenol 3 are prepared and characterised by single crystal X-ray diffraction studies and 13C{1H}NMR spectroscopy; the position of the C(2)13C resonance for the ester is used to predict the position of resonant frequency of the equivalent carbon in the parent alcohols and hence, calculate the position of the azo-hydrazone equilibrium in these compounds.

Investigating Sorption on Iron−Oxyhydroxide Soil Minerals by Solid-State NMR Spectroscopy:  A6Li MAS NMR Study of Adsorption and Absorption on Goethite

2005 ◽  
Vol 109 (39) ◽  
pp. 18310-18315 ◽  
Author(s):  
Ulla Gro Nielsen ◽  
Younkee Paik ◽  
Keinia Julmis ◽  
Martin A. A. Schoonen ◽  
Richard J. Reeder ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Solid State Nmr ◽  
Mas Nmr ◽  
Iron Oxyhydroxide ◽  
Soil Minerals ◽  
Solid State Nmr Spectroscopy ◽  
Nmr Study

scholarly journals Screening of phospholipase A activity and its production by new actinomycete strains cultivated by solid-state fermentation

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3524 ◽  
Author(s):  
Priscila Sutto-Ortiz ◽  
María de los Angeles Camacho-Ruiz ◽  
Manuel R. Kirchmayr ◽  
Rosa María Camacho-Ruiz ◽  
Juan Carlos Mateos-Díaz ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Fermentation ◽  
High Throughput Screening ◽  
Egg Yolk ◽  
Specific Substrate ◽  
Phospholipase Activity ◽  
High Accumulation ◽  
Egg Yolk Phosphatidylcholine ◽  
Potential Applications ◽  
Routine Assay

Novel microbial phospholipases A (PLAs) can be found in actinomycetes which have been poorly explored as producers of this activity. To investigate microbial PLA production, efficient methods are necessary such as high-throughput screening (HTS) assays for direct search of PLAs in microbial cultures and cultivation conditions to promote this activity. About 200 strains isolated with selected media for actinomycetes and mostly belonging toStreptomyces(73%) andMicromonospora(10%) genus were first screened on agar-plates containing the fluorophore rhodamine 6G and egg yolk phosphatidylcholine (PC) to detect strains producing phospholipase activity. Then, a colorimetric HTS assay for general PLA activity detection (cHTS-PLA) using enriched PC (≈60%) as substrate and cresol red as indicator was developed and applied; this cHTS-PLA assay was validated with known PLAs. For the first time, actinomycete strains were cultivated by solid-state fermentation (SSF) using PC as inductor and sugar-cane bagasse as support to produce high PLA activity (from 207 to 2,591 mU/g of support). Phospholipase activity of the enzymatic extracts from SSF was determined using the implemented cHTS-PLA assay and the PC hydrolysis products obtained, were analyzed by TLC showing the presence of lyso-PC. Three actinomycete strains of theStreptomycesgenus that stood out for high accumulation of lyso-PC, were selected and analyzed with the specific substrate 1,2-α-eleostearoyl-sn-glycero-3-phosphocholine (EEPC) in order to confirm the presence of PLA activity in their enzymatic extracts. Overall, the results obtained pave the way toward the HTS of PLA activity in crude microbial enzymatic extracts at a larger scale. The cHTS-PLA assay developed here can be also proposed as a routine assay for PLA activity determination during enzyme purification,directed evolution or mutagenesis approaches. In addition, the production of PLA activity by actinomycetes using SSF allow find and produce novel PLAs with potential applications in biotechnology.

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