scholarly journals Isolation and Study of the Chemical Structure of Low Molecular Weight Glycopeptides from Micrococcus lysodeikticus Cell Walls

1967 ◽  
Vol 242 (15) ◽  
pp. 3414-3427 ◽  
Author(s):  
David Mirelman ◽  
Nathan Sharon
Keyword(s):  
Molecular Weight ◽  
Cell Walls ◽  
Chemical Structure ◽  
Low Molecular Weight ◽  
Micrococcus Lysodeikticus

scholarly journals Characterisation of Sequential Solvent Fractionation and Base-catalysed Depolymerisation of Treated Alkali Lignin

BioResources ◽  
2015 ◽  
Vol 10 (3) ◽  
pp. 4137-4151 ◽  
Author(s):  
Aikfei Ang ◽  
Zaidon Ashaari ◽  
Edi Suhaimi Bakar ◽  
Nor Azowa Ibrahim
Keyword(s):  
Molecular Weight ◽  
Chemical Structure ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Solubility Parameters ◽  
Low Molecular Weight ◽  
Sequential Fractionation ◽  
Weight Average Molecular Weight ◽  
Solvent Fractionation ◽  
Alkali Lignin

An alkali lignin (OL) with a weight-average molecular weight (Mw) of 11646 g/mol was used to prepare low-molecular weight lignin for resin synthesis. The low-molecular weight lignin feedstock was obtained via base-catalysed depolymerisation (BCD) treatments at different combined severity factors. Sequential fractionation of the OL and BCD-treated lignins using organic solvents with different Hildebrand solubility parameters were used to alter the homogeneity of the OL. The yield and properties of OL itself and OL and BCD-treated OL dissolved in propan-1-ol (F1), ethanol (F2), and methanol (F3) were determined. Regardless of the treatment applied, a small amount of OL was dissolved in F1 and F2. The BCD treatment did not increase the yield of F1 but did increase the yields of F2 and F3. Gel permeation chromatography (GPC) showed that the repolymerization reaction occurred in F3 for all BCD-treated OL, so these lignins were not suitable for use as feedstocks for resin production. The GPC, 13Carbon-nuclear magnetic resonance, and Fourier transform infrared spectroscopy analyses confirmed that the F3 in OL exhibited the optimum yield, molecular weight distribution, and chemical structure suitable for use as feedstocks for resin synthesis.

scholarly journals Neuroprotective Metabolites from Vietnamese Marine Derived Fungi of Aspergillus and Penicillium Genera

Marine Drugs ◽  
2020 ◽  
Vol 18 (12) ◽  
pp. 608
Author(s):  
Elena V. Girich ◽  
Anton N. Yurchenko ◽  
Olga F. Smetanina ◽  
Phan Thi Hoai Trinh ◽  
Ngo Thi Duy Ngoc ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Secondary Metabolites ◽  
Cell Viability ◽  
Chemical Structure ◽  
Aspergillus Terreus ◽  
Marine Fungi ◽  
2D Nmr ◽  
Natural Source ◽  
Low Molecular Weight ◽  
First Time

Low molecular weight secondary metabolites of marine fungi Aspergillus flocculosus, Aspergillus terreus and Penicillium sp. from Van Phong and Nha Trang Bays (Vietnam) were studied and a number of polyketides, bis-indole quinones and terpenoids were isolated. The structures of the isolated compounds were determined by 1D and 2D NMR and HR-ESI-MS techniques. Stereochemistry of some compounds was established based on ECD data. A chemical structure of asterriquinone F (6) was thoroughly described for the first time. Anthraquinone (13) was firstly obtained from a natural source. Neuroprotective influences of the isolated compounds against 6-OHDA, paraquat and rotenone toxicity were investigated. 4-Hydroxyscytalone (1), 4-hydroxy-6-dehydroxyscytalone (2) and demethylcitreoviranol (3) have shown significant increasing of paraquat- and rotenone-treated Neuro-2a cell viability and anti-ROS activity.

scholarly journals Products of Metabolism and Processing of Lactic Acid Bacteria as Functional Ingredients

2018 ◽  
Vol 1 (1) ◽  
pp. 47 ◽  
Author(s):  
Antonina Ivanovna Kapustian ◽  
Natalia Cherno ◽  
Alexei Kovalenko ◽  
Kristina Naumenko ◽  
Igor Kushnir
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Organic Acids ◽  
Cell Walls ◽  
Degradation Products ◽  
Lactobacillus Delbrueckii ◽  
Low Molecular Weight ◽  
Gel Chromatography

Lactic acid bacteria (LAB) and bifidobacteria (BB) are unique substances that have a lot of biological and physiological effects. Structural components of LAB and BB – peptidoglycans, compounds of the muramylpeptide series, teichoic acids – have powerful immunological properties. Metabolites of LAB and BB – organic acids, hydrogen peroxide, bacteriocins, etc. – provide antagonistic activity, have an indirect impact on the immune system, reducing the antigenic load caused by pathogenic microorganisms. The expediency of peptidoglycans degradation of LAB and BB cell walls is substantiated. Low molecular weight products of the degradation can easily be absorbed and enter into biochemical processes, accelerating the expected functional-physiological effect. To obtain low-molecular products of peptidoglycans degradation, a combination of LAB and BB was used. The combination of LAB and BB is the sum of the test cultures of Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. Bulgaricus, Bifidobacterium bifidum, Lactococcus cremoris, Streptococcus termophilus. Destruction of peptidoglycans of bacterial cell walls was carried out using a combination of disintegrating factors. The efficiency of destruction was determined by the accumulation of low molecular weight peptides (with molecular weight up to 1500 Da), amino acids and soluble protein in the disintegrate. It has been established that the highest accumulation of low molecular weight degradation products occurs when using autolysis followed by enzymatic hydrolysis during 180 min with the ratio of the enzyme : substrate 1 : 100. At the same time ≈ 53% of protein substances pass from insoluble to soluble state. The molecular weight of the obtained products is determined by the gel chromatography method. The qualitative and quantitative content of organic acids, amino acids and vitamins of group В in the hydrolysis products composition was investigated. It was shown that the obtained product possesses high biological effect in the experiment on animals.

The chemical structure of lysozyme substrates and their cleavage by the enzyme

1967 ◽  
Vol 167 (1009) ◽  
pp. 402-415 ◽  
Keyword(s):  
Paper Chromatography ◽  
Active Site ◽  
Cell Walls ◽  
Chemical Structure ◽  
Enzymic Activity ◽  
Fluorescence Studies ◽  
Tryptophan Residues ◽  
Micrococcus Lysodeikticus ◽  
Hydrolysis Of ◽  
Long Chain

The isolation of a disaccharide, N -acetyl- β -D-glucosaminyl-(1 → 4) N -acetylmuramic acid ( NAG-NAM ) and a corresponding tetrasaccharide, from lysozyme digests of Micrococcus lysodeikticus cell walls, is described. These compounds have been used for the study of the enzymic activity of lysozyme. Digestion of the tetrasaccharide into disaccharide has been followed by ( a ) paper chromatography, ( b ) colorimetry, using the Morgan-Elson reaction, and ( c ) polarimetry. Lysozyme was found to catalyse transglycosylation in addition to hydrolysis, and it is proposed that hydrolysis of the tetrasaccharide does not proceed by direct cleavage, but by a transfer mechanism, via long chain oligosaccharides. N -acetyl-glucosamine and closely related oligosaccharides strongly inhibit the enzymic activity of lysozyme. Fluorescence studies show that these inhibitors interact with the tryptophan residues in the active site of the enzyme.

Terpenes, Phenylpropanoids, Sulfur and Other Essential Oil Constituents as Inhibitors of Cholinesterases

2020 ◽  
Vol 27 (26) ◽  
pp. 4297-4343 ◽  
Author(s):  
Franko Burčul ◽  
Ivica Blažević ◽  
Mila Radan ◽  
Olivera Politeo
Keyword(s):  
Molecular Weight ◽  
Biological Activity ◽  
Essential Oils ◽  
Functional Groups ◽  
Organic Compounds ◽  
Chemical Structure ◽  
Low Molecular Weight ◽  
Active Compounds ◽  
Oxygenated Compounds ◽  
Nitrogen Containing Compounds

: Essential oils constituents are a diverse family of low molecular weight organic compounds with comprehensive biological activity. According to their chemical structure, these active compounds can be divided into four major groups: terpenes, terpenoids, phenylpropenes, and "others". In addition, they may contain diverse functional groups according to which they can be classified as hydrocarbons (monoterpenes, sesquiterpenes, and aliphatic hydrocarbons); oxygenated compounds (monoterpene and sesquiterpene alcohols, aldehydes, ketones, esters, and other oxygenated compounds); and sulfur and/or nitrogen containing compounds (thioesters, sulfides, isothiocyanates, nitriles, and others). : Compounds that act as cholinesterase inhibitors still represent the only pharmacological treatment of Alzheimer´s disease. Numerous in vitro studies showed that some compounds, found in essential oils, have a promising cholinesterase inhibitory activity, such as α-pinene, δ-3-carene, 1,8-cineole, carvacrol, thymohydroquinone, α- and β-asarone, anethole, etc. : Essential oils constituents are a diverse family of low molecular weight organic compounds with comprehensive biological activity. According to their chemical structure, these active compounds can be divided into four major groups: terpenes, terpenoids, phenylpropenes, and "others". In addition, they may contain diverse functional groups according to which they can be classified as hydrocarbons (monoterpenes, sesquiterpenes, and aliphatic hydrocarbons); oxygenated compounds (monoterpene and sesquiterpene alcohols, aldehydes, ketones, esters, and other oxygenated compounds); and sulfur and/or nitrogen containing compounds (thioesters, sulfides, isothiocyanates, nitriles, and others).

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