CONSTITUTIONS OF POLYSACCHARIDES FROM SERRATIA MARCESCENS

1962 ◽  
Vol 40 (7) ◽  
pp. 1415-1424 ◽  
Author(s):  
H. C. Srivastava ◽  
G. A. Adams
Keyword(s):  
Serratia Marcescens ◽  
Acid Hydrolysis ◽  
Main Chain ◽  
Degree Of Branching ◽  
Chemical Structures ◽  
Mannuronic Acid ◽  
Phenol Extraction ◽  
Glycosidic Bonds ◽  
Similar Chemical ◽  
Acidic Components

Constitutional studies of three polysaccharides prepared from Serratia marcescens cells by a sequence of phenol extraction, ultracentrifugation, and fractionation by Cetavlon are described. Methylation of the polysaccharides followed by acid hydrolysis yielded 2,3,4,6-tetra-O-methyl-D-glucose, 2,4,6-tri-O-methyl-D-glucose, 2,4,6-tri-O-methyl-D-mannose, 4,6-di-O-methyl-D-glucose, 2,6-di-O-methyl-D-glucose, and an unidentified di-O-methyl-glucose. The acidic components found were: 2,3,4-tri-O-methyl-D-mannuronic acid, 3-O-(2,3,4-tri-O-methyl-D-mannuronosyl)-2,4,6-tri-O-methyl-D-glucose, and O-2,3,4-tri-O-methyl-D-mannuronosyl-(1 → 3)-O-2,4,6-tri-O-methyl-D-glucosyl-(1 → 3)-2,4,G-tri-O-methyl-D-glucose. The polysaccharides are composed of a main chain of D-glucose and D-mannose residues joined by 1,3-glycosidic bonds. Some glucose residues carry branches at C2 and C4 which terminate in either D-glucose or D-mannuronic acid residues. The three polysaccharides studied had similar chemical structures but varied in the amounts of component sugars and degree of branching.

PREPARATION AND PROPERTIES OF POLYSACCHARIDE–LIPID COMPLEXES FROM SERRATIA MARCESCENS

1962 ◽  
Vol 40 (7) ◽  
pp. 905-918 ◽  
Author(s):  
H. C. Srivastava ◽  
Evelyn Breuninger ◽  
Hugh J. Creech ◽  
G. A. Adams
Keyword(s):  
Serratia Marcescens ◽  
Glucuronic Acid ◽  
Antitumor Agent ◽  
Biological Properties ◽  
Culture Conditions ◽  
Aqueous Acetone ◽  
Uronic Acids ◽  
High Solubility ◽  
Mannuronic Acid ◽  
Phenol Extraction

Several polysaccharide fractions possessing pronounced antitumor activity were isolated from the polysaccharide–lipid–protein complex elaborated by Serratia marcescens. These fractions were obtained after phenol extraction of the cellular material, by ultracentrifugation and precipitation with ethanol and Cetavlon. They contained glucose, mannose, rhamnose, glucosamine, glucuronic acid, and mannuronic acid in different proportions. Each representative fraction caused regression of well-established solid tumors in mice but the dosage requirements varied considerably. One fraction containing glucose, mannose, and glucosamine, but no uronic acids, and having a high solubility in dilute sodium chloride solution and in aqueous acetone, was an exceptionally potent antitumor agent. Another fraction containing galactose and arabinose in addition to several of the usual components was found to be least active. From this work and that of other investigators, it is apparent that Serratia marcescens produces a spectrum of polysaccharides and lipopolysaccharides, the chemical composition and biological properties of which depend on the strain of organism, the culture conditions, and the methods employed for isolation of the active agents.

PREPARATION AND PROPERTIES OF POLYSACCHARIDE–LIPID COMPLEXES FROM SERRATIA MARCESCENS

1962 ◽  
Vol 40 (1) ◽  
pp. 905-918 ◽  
Author(s):  
H. C. Srivastava ◽  
Evelyn Breuninger ◽  
Hugh J. Creech ◽  
G. A. Adams
Keyword(s):  
Serratia Marcescens ◽  
Glucuronic Acid ◽  
Antitumor Agent ◽  
Biological Properties ◽  
Culture Conditions ◽  
Aqueous Acetone ◽  
Uronic Acids ◽  
High Solubility ◽  
Mannuronic Acid ◽  
Phenol Extraction

Several polysaccharide fractions possessing pronounced antitumor activity were isolated from the polysaccharide–lipid–protein complex elaborated by Serratia marcescens. These fractions were obtained after phenol extraction of the cellular material, by ultracentrifugation and precipitation with ethanol and Cetavlon. They contained glucose, mannose, rhamnose, glucosamine, glucuronic acid, and mannuronic acid in different proportions. Each representative fraction caused regression of well-established solid tumors in mice but the dosage requirements varied considerably. One fraction containing glucose, mannose, and glucosamine, but no uronic acids, and having a high solubility in dilute sodium chloride solution and in aqueous acetone, was an exceptionally potent antitumor agent. Another fraction containing galactose and arabinose in addition to several of the usual components was found to be least active. From this work and that of other investigators, it is apparent that Serratia marcescens produces a spectrum of polysaccharides and lipopolysaccharides, the chemical composition and biological properties of which depend on the strain of organism, the culture conditions, and the methods employed for isolation of the active agents.

scholarly journals Synthesis and Biological Activity of New Brassinosteroid Analogs of Type 24-Nor-5β-Cholane and 23-Benzoate Function in the Side Chain

2021 ◽  
Vol 22 (9) ◽  
pp. 4808
Author(s):  
Nitza Soto ◽  
Karoll Ferrer ◽  
Katy Díaz ◽  
César González ◽  
Lautaro Taborga ◽  
...  
Keyword(s):  
Good Alternative ◽  
Positive Control ◽  
Starting Material ◽  
Chemical Structures ◽  
High Reaction ◽  
Similar Chemical ◽  
Synthetic Procedure ◽  
Hyodeoxycholic Acid ◽  
External Stresses

Brassinosteroids are polyhydroxysteroids that are involved in different plants’ biological functions, such as growth, development and resistance to biotic and external stresses. Because of its low abundance in plants, much effort has been dedicated to the synthesis and characterization of brassinosteroids analogs. Herein, we report the synthesis of brassinosteroid 24-nor-5β-cholane type analogs with 23-benzoate function and 22,23-benzoate groups. The synthesis was accomplished with high reaction yields in a four-step synthesis route and using hyodeoxycholic acid as starting material. All synthesized analogs were tested using the rice lamina inclination test to assess their growth-promoting activity and compare it with those obtained for brassinolide, which was used as a positive control. The results indicate that the diasteroisomeric mixture of monobenzoylated derivatives exhibit the highest activity at the lowest tested concentrations (1 × 10−8 and 1 × 10−7 M), being even more active than brassinolide. Therefore, a simple synthetic procedure with high reaction yields that use a very accessible starting material provides brassinosteroid synthetic analogs with promising effects on plant growth. This exploratory study suggests that brassinosteroid analogs with similar chemical structures could be a good alternative to natural brassinosteroids.

Molecular Motion Analysis of 5CB in PDLCs Using Solid-State 13C NMR Relaxation Spectroscopy

1993 ◽  
Vol 47 (7) ◽  
pp. 933-941 ◽  
Author(s):  
Karen L. Buchert ◽  
Jack L. Koenig ◽  
Shi-Qing Wang ◽  
John L. West
Keyword(s):  
Liquid Crystal ◽  
Solid State ◽  
Polymer Matrix ◽  
Nmr Relaxation ◽  
Domain Size ◽  
Chemical Structures ◽  
Similar Chemical ◽  
Polymer Dispersed ◽  
Submicron Droplets ◽  
Significant Change

In samples of polymer-dispersed liquid crystals (PDLCs), submicron droplets of liquid crystal reside within a polymer matrix. By the use of the cross polarization technique for solid-state 13C NMR spectroscopy, the NMR spectrum of the liquid crystal can be obtained without interference from the polymer spectrum, even though the two materials have some similar chemical structures. Both 13C T1 and 13C T1 ρ relaxation experiments were performed on a PDLC system of 5CB in epoxy as a function of 5CB domain size. The 13C T1 relaxation constants and the localized motions they measure showed no significant change over the liquid crystal domain size studied. However, the 13C T1 ρ relaxation constants and the segmental motions of molecules they measure revealed a significant change over the liquid crystal domain size studied. Therefore, the 13C T1 ρ values can be used to determine the change in mobility of the molecular segments of the SCB molecules resulting from increased interaction between the liquid crystal and the polymer matrix and to further understand the importance of the molecular motions of the liquid crystal in the switching phenomenon for PDLC materials.

All-atomistic molecular dynamics study of the glass transition of amorphous polymers

2021 ◽  
Author(s):  
Zhiye Tang ◽  
Susumu Okazaki
Keyword(s):  
Molecular Dynamics ◽  
Glass Transition ◽  
Spatial Scale ◽  
Degrees Of Freedom ◽  
Main Chain ◽  
Polymer Materials ◽  
Coarse Grained ◽  
Mode Analysis ◽  
Radius Of Gyration ◽  
Chemical Structures

Glass transition is an important phenomenon of polymer materials and it has been intensively studied over the past a few decades. However, the influencing factors arising from the chemical structures of the polymers are often ignored due to a continuous or coarse-grained description of the polymer. Here, we approached this phenomenon using all-atomistic molecular dynamics (MD) simulations and two conventionally used polymer materials, polycarbonate (PC) and poly-(methyl methacrylate) (PMMA). We reproduced the glass transition temperatures (Tg) of the two materials reasonably well. Then we characterized and investigated the glass transition process by looking at the changes of potential energy, dihedral transition, and thermal fluctuation of the individual degrees of freedom in the systems, over the entire temperature range of glass transition. As previously reported, the dihedral angles stop their conformational changes gradually at the Tg, especially for the main chain dihedrals, and sidechain rotations immediately rooting from the main chain. The volumetric change during the temperature decrease is confirmed to be because of conformational adjustment, probably due to the tendency of chain stretching for the maintenance of the radius of gyration, and the loss of thermal energy. The strength of motions of single degrees of freedom and polymer chains, and overall slow motions obtained by normal mode analysis (NMA) shows that different motions at different spatial scale may gradually stop at distinct temperature in the MD simulation temporal and spatial scales. Presumably, the small spatial scale do not contribute to the glass transition at the experimental scale since the timescale is much longer than their relaxation time.

POLYSACCHARIDE-PEPTIDE COMPLEXES FROM SERRATIA MARCESCENS CELLS

1964 ◽  
Vol 42 (5) ◽  
pp. 593-603 ◽  
Author(s):  
Hugh J. Creech ◽  
Evelyn R. Breuninger ◽  
G. A. Adams
Keyword(s):  
Chemical Composition ◽  
Serratia Marcescens ◽  
High Speed ◽  
Complete Removal ◽  
Complete Regression ◽  
Aqueous Extracts ◽  
Amino Acid Residues ◽  
Phenol Extraction ◽  
Peptide Complexes ◽  
Antitumor Properties

Determinations were made of the chemical composition and antitumor properties of several polysaccharide fractions obtained by high speed centrifugation of aqueous extracts of the cells of Serratia marcescens following phenol extraction and trypsin digestion. The use of methods that ensured complete removal of lipid gave polysaccharides containing firmly bound amino acid residues. These were highly effective in causing complete regression of well established solid tumors in mice. The products derived primarily from the cell wall were more potent than the polysaccharides of extracellular and cytoplasmic origins. Extensive differences were also noted in the chemical composition of the polysaccharide complexes isolated from the two sources.

scholarly journals Competitive cocrystallization and its application in the separation of flavonoids

IUCrJ ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 195-207
Author(s):  
Yanming Xia ◽  
Yuanfeng Wei ◽  
Hui Chen ◽  
Shuai Qian ◽  
Jianjun Zhang ◽  
...  
Keyword(s):  
Free Energy ◽  
Formation Constant ◽  
Energy Gap ◽  
Hirshfeld Surface ◽  
Methanol Solution ◽  
Model Compounds ◽  
Electronic Density ◽  
Chemical Structures ◽  
Similar Chemical ◽  
Interaction Contribution

Recently, cocrystallization has been widely employed to tailor physicochemical properties of drugs in the pharmaceutical field. In this study, cocrystallization was applied to separate natural compounds with similar structures. Three flavonoids [baicalein (BAI), quercetin (QUE) and myricetin (MYR)] were used as model compounds. The coformer caffeine (CAF) could form cocrystals with all three flavonoids, namely BAI–CAF (cocrystal 1), QUE–CAF (cocrystal 2) and MYR–CAF (cocrystal 3). After adding CAF to methanol solution containing MYR and QUE (or QUE and BAI), cocrystal 3 (or cocrystal 2) preferentially formed rather than cocrystal 2 (or cocrystal 1), indicating that flavonoid separation could be achieved by competitive cocrystallization. After co-mixing the slurry of two flavonoids with CAF followed by centrifugation, the resolution ratio that could be achieved was 70–80% with purity >90%. Among the three cocrystals, cocrystal 3 showed the lowest formation constant with a negative Gibbs free energy of nucleation and the highest energy gap. Hirshfeld surface analysis and density of states analysis found that cocrystal 3 had the highest strong interaction contribution and the closest electronic density, respectively, followed by cocrystal 2 and cocrystal 1, suggesting CAF could competitively form a cocrystal with MYR much more easily than QUE and BAI. Cocrystallization is a promising approach for green and effective separation of natural products with similar chemical structures.

scholarly journals Dinucleoside polyphosphates act as 5’-RNA caps in Escherichia coli

2019 ◽  
Author(s):  
Oldřich Hudeček ◽  
Roberto Benoni ◽  
Martin Culka ◽  
Martin Hubálek ◽  
Lubomír Rulíšek ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Rna Stability ◽  
E Coli ◽  
Chemical Structures ◽  
Additional Layer ◽  
Similar Chemical ◽  
Decapping Enzyme ◽  
Almost All ◽  
Dinucleoside Polyphosphates ◽  
Rna Caps

Dinucleoside polyphosphates (NpnNs), discovered more than 50 years ago,1 are pleiotropic molecules present in almost all types of cells.2 It has been shown that their intracellular concentration can under stress conditions increase from the µM to mM range 2,3. However, the cellular roles and mechanisms of action of NpnNs are still speculative4,5. They have never been considered as part of the RNA, even though they have similar chemical structures as already known RNA caps, such as the nicotinamide adenine dinucleotide (NAD)6-8 and 7-methylguanylate cap9. Here, we show that both methylated and non-methylated Npn Ns serve as RNA caps in Escherichia coli (E. coli). NpnNs are excellent substrates for T7 and E. coli RNA polymerases (RNAP) and efficiently initiate transcription. Further, we demonstrate that the E. coli decapping enzyme RNA 5’ pyrophosphohydrolase (RppH) is able to remove the NpnNs-cap from the RNA. RppH was, however, not able to cleave the methylated forms of the NpnN-caps, suggesting that the methylation adds an additional layer to the RNA stability regulation. Our work introduces an original perspective on the chemical structure of RNA in prokaryotes and the function of RNA caps. This is the first evidence that small molecules like NpnNs can act in cells via their incorporation into RNA and influence the cellular metabolism.

scholarly journals Effects of Petroleum-Based Oils as Dispersing Aids on Physicochemical Characteristics of Magnetorheological Elastomers

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7026
Author(s):  
Norizatie Muhammad Zaki ◽  
Nurul Azhani Yunus ◽  
Muhamad Shakir Yusoff ◽  
Saiful Amri Mazlan ◽  
Siti Aishah Abdul Aziz ◽  
...  
Keyword(s):  
Magnetic Particles ◽  
Physicochemical Characteristics ◽  
Magnetorheological Elastomers ◽  
Weight Percentage ◽  
Chemical Structures ◽  
Microstructure Observation ◽  
Curing Characteristics ◽  
Similar Chemical ◽  
Low Performance ◽  
Light Mineral

This paper investigated the effects of petroleum-based oils (PBOs) as a dispersing aid on the physicochemical characteristics of natural rubber (NR)-based magnetorheological elastomers (MREs). The addition of PBOs was expected to overcome the low performance of magnetorheological (MR) elastomers due to their inhomogeneous dispersion and the mobility of magnetic particles within the elastomer matrix. The NR-based MREs were firstly fabricated by mixing the NR compounds homogeneously with different ratios of naphthenic oil (NO), light mineral oil (LMO), and paraffin oil (PO) to aromatic oil (AO), with weight percentage ratios of 100:0, 70:30, 50:50, and 30:70, respectively. From the obtained results, the ratios of NO mixed with low amounts of AO improved the material physicochemical characteristics, such as thermal properties. Meanwhile, LMO mixed the AO led to the best results for curing characteristics, microstructure observation, and magnetic properties of the MREs. We found that the LMO mixed with a high content of AO could provide good compatibility between the rubber molecular and magnetic particles due to similar chemical structures, which apparently enhance the physicochemical characteristics of MREs. In conclusion, the 30:70 ratio of LMO:AO is considered the preferable dispersing aid for MREs due to structural compounds present in the oil that enhance the physicochemical characteristics of the NR-based MREs.

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