scholarly journals Stereoselective Synthesis of Novel Sphingoid Bases Utilized for Exploring the Secrets of Sphinx

2021 ◽  
Vol 22 (15) ◽  
pp. 8171
Author(s):  
Essa M. Saied ◽  
Christoph Arenz
Keyword(s):  
Plasma Membranes ◽  
Stereoselective Synthesis ◽  
Chemical Characterization ◽  
Great Promise ◽  
Sphingoid Bases ◽  
Animal Physiology ◽  
Pathological Conditions ◽  
Low Concentrations ◽  
Derivatives Of

Sphingolipids are ubiquitous in eukaryotic plasma membranes and play major roles in human and animal physiology and disease. This class of lipids is usually defined as being derivatives of sphingosine, a long-chain 1,3-dihydroxy-2-amino alcohol. Various pathological conditions such as diabetes or neuropathy have been associated with changes in the sphingolipidome and an increased biosynthesis of structurally altered non-canonical sphingolipid derivatives. These unusual or non-canonical sphingolipids hold great promise as potential diagnostic markers. However, due to their low concentrations and the unavailability of suitable standards, the research to explore the secret of this class of ‘Sphinx’ lipids is ultimately hampered. Therefore, the development of efficient and facile syntheses of standard compounds is a key endeavor. Here, we present various chemical approaches for stereoselective synthesis and in-depth chemical characterization of a set of novel sphingoid bases which were recently utilized as valuable tools to explore the metabolism and biophysical properties of sphingolipids, but also to develop efficient analytical methods for their detection and quantification.

scholarly journals Partial Chemical Characterization of S-Carboxymethylated Chains of Rabbit Fibrin(OGEN): Evidence for Separate Chain Biosynthesis

1977 ◽  
Author(s):  
B. Alving ◽  
G. Murano ◽  
D. Walz
Keyword(s):  
Amino Acid ◽  
Specific Activity ◽  
Chemical Characterization ◽  
Molecular Size ◽  
Exchange Chromatography ◽  
12 Steps ◽  
Polypeptide Chains ◽  
Sds Electrophoresis ◽  
Derivatives Of

The purpose of this study was twofold: 1) chemically characterize the isolated polypeptide chains of rabbit fibrin(ogen), and 2) explore their mode of biosynthesis. The three S-carboxy-methyl polypeptide chain derivatives of rabbit fibrin (α, β and γ) were isolated by cation exchange chromatography. Their amino acid composition was similar to the human with a methionine distribution (mole/mole) as follows: γ = 9; β = 14, α = 14. Their molecular size, (SDS electrophoresis) was estimated as follows: γ = 46,000; β = 54,000; α = 63,500. The N-terminal amino acid sequence (12 steps) of the β derivative was:Gly-His-Arg-Pro-Ile-Asp-Arg-Arg-Arg-Glu-Glu-Leu-. To determine whether the three chains are synthesized sequentially (one continuous chain, later split into three) or in parallel, turpentine-stimulated male New Zealand rabbits were given ~40 μCi of [75Se] selenomethionine (SeM) and its incorporation into fibrinogen (F) was followed. F was clotted from plasma samples, washed, reduced, and constituent chains separated by gel electrophoresis in the presence of SDS-urea. The radioactivity of each chain (expressed as percent of total F radioactivity) was determined, and the specific methionine radioactivity calculated for each chain isolated at 20, 25, and 30 min after SeM injection. During this interval the specific activity of the α and the γ chains was essentially the same (within 3%) while that of the β chain was 42 to 97% greater than that of the α chain. The similar activity of the α and γ chains during the early phase of SeM incorporation suggests that these two chains are not synthesized sequentially, rather they are synthesized in parallel.

Physico-Chemical Characterization of Some 5,5-Disubstituted-1,3-Dixanthyl Barbituric Acids

1967 ◽  
Vol 21 (4) ◽  
pp. 225-231 ◽  
Author(s):  
B. C. Flann ◽  
J. A. R. Cloutier
Keyword(s):  
Experimental Data ◽  
Powder Diffraction ◽  
Infrared Spectra ◽  
Chemical Characterization ◽  
Melting Points ◽  
X Ray ◽  
Physico Chemical ◽  
Diffraction Patterns ◽  
Derivatives Of

The dixanthyl derivatives of 21 clinically important barbituric acids have been prepared. Melting points, infrared spectra, and x-ray powder-diffraction patterns of the purified compounds are presented. Infrared evidence is used to discuss the position of the linkage between the xanthyl and barbiturate portions of the derivatives. The experimental data should prove of particular value for the microchemical identification of barbiturates.

N-arylmethylideneaminophthalimide: Design, Synthesis and Evaluation as Analgesic and Anti-inflammatory Agents

2019 ◽  
Vol 19 (8) ◽  
pp. 679-687 ◽  
Author(s):  
Nasimossadat Banarouei ◽  
Asghar Davood ◽  
Hamed Shafaroodi ◽  
Ghazaleh Saeedi ◽  
Abbas Shafiee
Keyword(s):  
Room Temperature ◽  
Antiinflammatory Activity ◽  
Chemical Characterization ◽  
Design Synthesis ◽  
Reference Drug ◽  
Anti Inflammatory ◽  
Pain Test ◽  
Derivatives Of

Background and Objective: N-aryl derivatives of phthalimide and 4-nitro phthalimide have demonstrated cyclooxygenase inhibitory activity. Also, they possess excellent analgesic and antiinflammatory activity. In this work, a new series of N-arylmethylideneamino derivatives of phthalimide and 4-nitro phthalimide were designed and synthesized. Methods: The designed compounds were synthesized by condensation of the appropriate aldehyde and N-aminophthalimide in ethanol at room temperature at PH around 3. Their analgesic and antiinflammatory activity were evaluated by acetic acid-induced pain test and carrageenan-induced paw edema test in mice and rats, respectively. Results and Conclusion:: The details of the synthesis and chemical characterization of the analogs are described. In vivo screening showed compounds 3a, 3b, 3f and 3h were the most potent analgesic compounds. In addition, compounds 3a, 3c, 3d, 3e and 3j indicated comparable anti-inflammatory activity to indomethacin as a reference drug.

scholarly journals Physical-Chemical Characterization and Mineralogic Analysis of Hydrothermal Systems Located in the Coconuco and the San Juan Sectors in Cauca, Colombia

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-19
Author(s):  
Darwin Augusto Torres-Ceron ◽  
Carlos Daniel Acosta-Medina ◽  
Elisabeth Restrepo-Parra
Keyword(s):  
Hot Springs ◽  
Major Ions ◽  
Hot Spring ◽  
Volcanic Rocks ◽  
Chemical Characterization ◽  
Hydrothermal Systems ◽  
San Juan ◽  
Low Concentrations ◽  
Agricultural Applications

Hot springs of the volcanic zones are characterized for having high sulfur content in the form of sulphate and other ions resulting from chemical reactions. Sources with these types of elements are of great interest for the tourism and geothermal industry because of their highlighted properties which include therapeutic treatments, relaxation baths, agricultural applications, and preservation of flora and fauna among others. For these reasons, research oriented to carry out the characterization of these factors is of great importance to determine the availability of places with such characteristics. This work shows the characterization of 17 hot spring sources located in the Coconuco and San Juan sectors (Cauca, Colombia, South America). Water samples were taken in May 2017, and laboratory analyses were carried out by the Water Laboratory at Universidad Nacional de Colombia-Manizales, based on the Standard Methods (APHA-AWWA-WEF). Rock samples were taken in November 2017, and laboratory analyses were carried out by the GMAS+ Laboratory (Bogotá, Colombia). The Piper, Stiff, and ternary (Giggenbach) diagrams were used for the classification of major ions. Mineralogy composition was determined through XRD and XRF. Results indicate that most sources are of the sulphated type according to the anions and of the calcium type according to the cations. In concordance with Giggenbach diagrams, most of the sources are immature waters and, despite their interaction with rocks, they have not achieved the equilibrium. Likewise, these sources are of heated vapor type and, considering that they consist of sulphated acid sources, it is not possible to evaluate the reservoir temperatures from Na/K cations. The low Ca2+/Mg2+ ratio in the sources indicates the lack of direct migration of fluids and the high content of Ca2+ and Mg2+ regarding Na+ and K+, which suggests that fluids possibly are mixed with cold waters rich in Ca2+ and Mg2+. From the mineralogic characterization, it was observed that volcanic rocks are composed of cristobalite and albite with TiO2, Fe2O3, and CaO traces and mineral sulfur. Metals like Cr, considered in this case as contaminants, are found in low concentrations in rocks and are not detected in these waters.

scholarly journals Synthesis and Characterization of Novel Atypical Sphingoid Bases

2020 ◽  
Author(s):  
Essa M. Saied ◽  
Christoph Arenz
Keyword(s):  
Analytical Data ◽  
Synthesis And Characterization ◽  
Sphingoid Bases ◽  
Pathological Conditions

The synthesis of atypical sphingoid bases is described. The compounds described here have been postulated from biochemical investigations for pathological conditions or certain tissues. Most of the compounds here have been confirmed. Full synthetic and analytical data is provided. <br>

scholarly journals Synthesis and Characterization of Novel Atypical Sphingoid Bases

2020 ◽  
Author(s):  
Essa M. Saied ◽  
Christoph Arenz
Keyword(s):  
Analytical Data ◽  
Synthesis And Characterization ◽  
Sphingoid Bases ◽  
Pathological Conditions

The synthesis of atypical sphingoid bases is described. The compounds described here have been postulated from biochemical investigations for pathological conditions or certain tissues. Most of the compounds here have been confirmed. Full synthetic and analytical data is provided. <br>

scholarly journals LC–HRMS and Chemical Derivatization Strategies for the Structure Elucidation of Caribbean Ciguatoxins: Identification of C-CTX-3 and -4

Marine Drugs ◽  
2020 ◽  
Vol 18 (4) ◽  
pp. 182 ◽  
Author(s):  
Fedor Kryuchkov ◽  
Alison Robertson ◽  
Christopher O. Miles ◽  
Elizabeth M. Mudge ◽  
Silvio Uhlig
Keyword(s):  
Chemical Characterization ◽  
Diagnostic Value ◽  
Chemical Derivatization ◽  
Oxidation Reactions ◽  
Structural Modifications ◽  
Low Concentrations ◽  
Simple Chemical ◽  
Product Ions ◽  
Mass Spectrometric Fragmentation

Ciguatera poisoning is linked to the ingestion of seafood that is contaminated with ciguatoxins (CTXs). The structural variability of these polyether toxins in nature remains poorly understood due to the low concentrations present even in highly toxic fish, which makes isolation and chemical characterization difficult. We studied the mass spectrometric fragmentation of Caribbean CTXs, i.e., the epimers C-CTX-1 and -2 (1 and 2), using a sensitive UHPLC–HRMS/MS approach in order to identify product ions of diagnostic value. We found that the fragmentation of the ladder-frame backbone follows a characteristic pattern and propose a generalized nomenclature for the ions formed. These data were applied to the structural characterization of a pair of so far poorly characterized isomers, C-CTX-3 and -4 (3 and 4), which we found to be reduced at C-56 relative to 1 and 2. Furthermore, we tested and applied reduction and oxidation reactions, monitored by LC–HRMS, in order to confirm the structures of 3 and 4. Reduction of 1 and 2 with NaBH4 afforded 3 and 4, thereby unambiguously confirming the identities of 3 and 4. In summary, this work provides a foundation for mass spectrometry-based characterization of new C-CTXs, including a suite of simple chemical reactions to assist the examination of structural modifications.

Use of cooling tower blow down in ethanol fermentation

2010 ◽  
Vol 62 (10) ◽  
pp. 2263-2269 ◽  
Author(s):  
N. Rajagopalan ◽  
V. Singh ◽  
B. Panno ◽  
M. Wilcoxon
Keyword(s):  
Water Consumption ◽  
Cooling Tower ◽  
Chemical Characterization ◽  
Production Costs ◽  
Blow Down ◽  
Good Tolerance ◽  
Low Concentrations ◽  
Residual Glucose ◽  
Control Study

Reducing water consumption in bioethanol production conserves an increasingly scarce natural resource, lowers production costs, and minimizes effluent management issues. The suitability of cooling tower blow down water for reuse in fermentation was investigated as a means to lower water consumption. Extensive chemical characterization of the blow down water revealed low concentrations of toxic elements and total dissolved solids. Fermentation carried out with cooling tower blow down water resulted in similar levels of ethanol and residual glucose as a control study using deionized water. The study noted good tolerance by yeast to the specific scale and corrosion inhibitors found in the cooling tower blow down water. This research indicates that, under appropriate conditions, reuse of blow down water from cooling towers in fermentation is feasible.

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