scholarly journals Direct Preparation of Nanocelluloses of Tunable Lengths from Native Wood Via Alkaline Periodate Oxidation

2021 ◽  
pp. 2100058
Author(s):  
Ting Yang ◽  
Peiwen Liu ◽  
Dan Xu ◽  
Jiaxiu Wang ◽  
Kai Zhang
Keyword(s):  
Periodate Oxidation ◽  
Direct Preparation

Cytochemical Studies of Cell Wall Biosynthesis in Staphylococcus Aureus

1972 ◽  
Vol 30 ◽  
pp. 328-329
Author(s):  
Masaatsu Koike ◽  
Koichi Nakashima ◽  
Kyoko Iida
Keyword(s):  
Staphylococcus Aureus ◽  
Periodate Oxidation ◽  
Early Time ◽  
The Other ◽  
Penicillin G ◽  
Cell Wall Biosynthesis ◽  
Septal Wall ◽  
Peptidoglycan Biosynthesis ◽  
Gram Positive Bacteria ◽  
Cross Linkage

Penicillin exerts the activity to inhibit the peptide cross linkage between each polysaccharide backbone at the final stage of wall-peptidoglycan biosynthesis of bacteria. Morphologically, alterations of the septal wall and mesosome in gram-positive bacteria, which were occurred in early time after treatment with penicillin, have been observed. In this experiment, these alterations were cytochemically investigated by means of silver-methenamine staining after periodate oxidation, which is applied for detection of localization of wall mucopolysaccharide.Staphylococcus aureus strain 209P treated with 100 u/ml of penicillin G was divided into two aliquotes. One was fixed by Kellenberger-Ryter's OSO4 fixative at 30, 60 and 120 min after addition of the antibiotic, dehydrated through alcohol series, and embedded in Epon 812 (Specimen A). The other was fixed by 21 glutaraldehyde, dehydrated through glycolmethacrylate series and embedded in glycolmethacrylate mixture, according to Bernhard's method (Specimen B).

A Mild and Simple Method for Making MIDA Boronates

2020 ◽  
Author(s):  
Aidan Kelly ◽  
Peng-Jui (Ruby) Chen ◽  
Jenna Klubnick ◽  
Daniel J. Blair ◽  
Martin D. Burke
Keyword(s):  
Organic Synthesis ◽  
Boronic Acids ◽  
Simple Method ◽  
Direct Preparation ◽  
Synthesis Procedure ◽  
Harsh Conditions

<div> <div> <div> <p>Existing methods for making MIDA boronates require harsh conditions and complex procedures to achieve dehydration. Here we disclose that a pre-dried form of MIDA, MIDA anhydride, acts as both a source of the MIDA ligand and an in situ desiccant to enable a mild and simple MIDA boronate synthesis procedure. This method expands the range of sensitive boronic acids that can be converted into their MIDA boronate counterparts. Further utilizing unique properties of MIDA boronates, we have developed a MIDA Boronate Maker Kit which enables the direct preparation and purification of MIDA boronates from boronic acids using only heating and centrifuge equipment that is widely available in labs that do not specialize in organic synthesis. </p> </div> </div> </div>

α-Ketophosphonates in the Synthesis of α-iminophosphonates

2020 ◽  
Vol 7 (2) ◽  
pp. 226-238
Author(s):  
Petro P. Ony`sko ◽  
Tetyana I. Chudakova ◽  
Vladimir V. Pirozhenko ◽  
Alexandr B. Rozhenko
Keyword(s):  
Bond Cleavage ◽  
Direct Synthesis ◽  
Equilibrium Mixture ◽  
Primary Amines ◽  
Alkyl Amines ◽  
Protic Solvents ◽  
Metallic Salts ◽  
Direct Preparation ◽  
Stage Synthesis ◽  
Aprotic Dipolar Solvent

The potentialities of condensation of α-ketophosphonates with primary amines for direct synthesis of α-iminophosphonates have been revealed. Diesters of α-ketophosphonic acids react with the primary amines by two competitive pathways: with a formation of α-iminophosphonates or a C-P bond cleavage resulting in a hydrogen phosphonate and an acylated amine. In many cases, the latter undesirable pathway is dominant, especially for more nucleophilic alkyl amines. Using metallic salts of α-ketophosphonates avoids the C-P bond cleavage, allowing direct preparation of α-phosphorylated imines by the reaction with primary amines. This strategy provides an atom economy single-stage synthesis of iminophosphonates – precursors of bio relevant phosphorus analogs of α-amino acids. Methyl sodium iminophosphonates, bearing aryl or heteryl substituents at the imino carbon atom exist in solutions at room temperature as an equilibrium mixture of Z- and E-isomers. A configuration of the C=N bond can be controlled by the solvent: changing the aprotic dipolar solvent DMSO-d6 by water or alcohols leads to the change from a predominant Z-isomer to almost an exclusive E-form. In contrast, diesters of the respective iminophosphonates exist in non-protic solvents predominantly in Econfiguration. The solvent effect on E-Z stereochemistry is demonstrated by DFT calculations.

Glucan isolated from leaves of Althaea officinalis L.

1983 ◽  
Vol 48 (7) ◽  
pp. 2082-2087 ◽  
Author(s):  
Alžbeta Kardošová ◽  
Jozef Rosík ◽  
Rudolf Toman ◽  
Peter Capek
Keyword(s):  
Medicinal Plant ◽  
Periodate Oxidation ◽  
Linear Structure ◽  
Water Soluble ◽  
Partial Hydrolysis ◽  
Methylation Analysis ◽  
Glycosidic Bonds ◽  
Nmr Data ◽  
Althaea Officinalis ◽  
C Nmr

A water-soluble low-molecular D-glucan was isolated from leaves of the medicinal plant marsh-mallow (Althaea officinalis L.). The results of methylation analysis, partial hydrolysis, periodate oxidation, and 13C NMR data indicated a virtually linear structure with α-(1→6) glycosidic bonds.

scholarly journals Effect of nanopolysaccharide (BSEPS) from Bacillus subtilis sp. on thioacetamide-induced liver fibrosis in rats

2019 ◽  
Vol 43 (1) ◽  
Author(s):  
Manal G. Mahmoud ◽  
Mohsen S. Asker ◽  
Mohamed E. El Awady ◽  
Amal I. Hassan ◽  
Nadia A. R. Zaharan ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Liver Fibrosis ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Periodate Oxidation ◽  
Hepatic Tissue ◽  
Albino Rats ◽  
Gamma Glutamyl Transferase ◽  
Glutamyl Transferase ◽  
Tgf Β1

Abstract Background Nanomedicine contributes to the efficiency of pharmacological treatments and progresses rapidly. The present study was designed to produce exopolysaccharide (BSEPS) from Bacillus subtilis sp. strain reported in our previous study was further characterized, and its BSEPS for synthesis of the nanoparticle Ag-BSEPS using microwave heating to determine the possible effects of a prepared solution containing Ag-BSEPS versus thioacetamide (TAA) evoked liver fibrosis in Wister albino rats. Nanoparticles with silver (Ag) core have been synthesized in an aqueous solution after exposure of BSEPS to periodate oxidation. Animals were split into four groups: I - control rats, water ad libitum for 6 weeks; II - rats were injected with TAA 200 mg/kg-1 3 times/week for 4 weeks IP; III - Ag-BSEPS 100 mg/kg-1 IP twice a week for 6 weeks; and IV - TAA, as group II followed by Ag-BSEPS as group III. The antifibrotic effects of Ag-BSEPS were appraised by determining different hepatotoxicity indices, oxidative stress, and inflammatory and liver fibrosis markers. Results Nanoparticles were obtained with a diameter size range of 50–100 nm characterized by SEM and TEM without using any harmful reagents. Results evinced considerably reduced activity of liver functions such as transaminases (AST, ALT), gamma-glutamyl transferase (GGT), and alkaline phosphatase (ALP) in the group which received TAA followed by Ag-BSEPS compared to the other group which received only TAA. In the current results, the administration of Ag-BSEPS showed an improvement in the proinflammatory cytokines. On the contrary, the antioxidant enzymes in liver homogenates revealed significant improvement (concentration of glutathione peroxidase (GSH-PX), superoxide dismutase (SOD), and catalase (CAT) increases) in animals with TAA-induced liver damage followed by Ag-BSEPS. Moreover, the activities of the fibrotic markers transforming growth factor-beta 1(TGF-β1) and type III pro-collagen (PCIII) were increased in liver tissues in the group which was given TAA alone as compared to the controls. The percentage of fibrosis of hepatic tissue had a positive correlation with the levels of PCIII and TGF-β1, followed by Ag-BSEPS compared to the TAA group without nanocomposite treatment. Microscopic examinations revealed inhibitory effects of Ag-BSEPS on inflammatory changes and deterrent of liver fibrosis. Conclusion It was suggested that the biochemical and histological amelioration observed in Ag-BSEPS (100 mg/kg-1 twice a week for 6 weeks) treated the fibrotic rats.

Preparing Process and Properties of Collagen Modified Cotton Fiber

2011 ◽  
Vol 236-238 ◽  
pp. 1415-1419 ◽  
Author(s):  
Yun Hui Xu ◽  
Zhao Fang Du
Keyword(s):  
Cotton Fiber ◽  
Treatment Time ◽  
Ph Value ◽  
Periodate Oxidation ◽  
Aqueous Acetic Acid ◽  
Collagen Concentration ◽  
Acid Media ◽  
Xps Characterization ◽  
Aldehyde Groups

In order to develop cotton fabric underwear with the health care function, the cotton fiber was modified with the collagen (CMCF) using periodate oxidation method. The aldehyde groups on the glucose chains of the oxidized cotton cellulose were reacted with the amino groups of collagen to obtain the CMCF, and the oxidized cellulose was crosslinked with collagen in aqueous acetic acid media. The effects of collagen concentration, treatment time, reaction temperature, pH value of solution and periodate concentration on the amount of collagen crosslinked on cotton fiber were respectively discussed, and the optimal reaction technology was obtained. XPS characterization of the modified cotton fiber showed a characteristic peak about 400.0–405.0 eV corresponding to collagen, which indicated that the collagen was combined on the surface of cotton fiber. The mechanical properties of the collagen modified cotton fiber were improved. The resulting CMCF is a new natural ecological fiber and has the extensive application as a carrier for the controlled release of drugs.

A WATER-SOLUBLE GALACTOMANNAN FROM COCONUT (COCOS NUCIFERA): PART I. METHYLATION STUDIES

1961 ◽  
Vol 39 (2) ◽  
pp. 375-381 ◽  
Author(s):  
C. V. N. Rao ◽  
D. Choudhury ◽  
P. Bagchi
Keyword(s):  
Cocos Nucifera ◽  
Periodate Oxidation ◽  
Water Soluble ◽  
Soluble Polysaccharide ◽  
Structural Significance

A water-soluble polysaccharide isolated from the kernel of coconut (Cocos nucifera) had [α]D −85° and contained D-galactose (1 mole) and D-mannose (2 moles). Methylation and hydrolysis yielded 2,3,4,6-tetra-O-methyl-D-mannose (0.51 mole); 2,3,4,6-tetra-O-methyl-D-galactose (0.5 mole); 2,3,6-tri-O-methyl-D-mannose (5.52 moles); 2,3,6-tri-O-methyl-D-galactose (1.51 moles); and a di-O-methyl-D-galactose (1 mole). These data agree with those of periodate oxidation. The structural significance of these results is discussed.

Production and use of monoclonal antibodies for identification of Bradyrhizobium japonicum strains

1988 ◽  
Vol 34 (1) ◽  
pp. 88-92 ◽  
Author(s):  
D. Velez ◽  
J. D. Macmillan ◽  
L. Miller
Keyword(s):  
Monoclonal Antibodies ◽  
Bradyrhizobium Japonicum ◽  
Chemical Nature ◽  
Periodate Oxidation ◽  
Enzyme Linked Immunosorbent Assay ◽  
Gram Negative Bacteria ◽  
Bacterial Cells ◽  
Gram Negative ◽  
Polyclonal Antisera ◽  
Somatic Antigens

Thirteen murine hybridomas capable of producing monoclonal antibodies to somatic antigens on Bradyrhizobium japonicum were developed and an indirect enzyme-linked immunosorbent assay was used to test reactivity of the antibodies against 20 strains of B. japonicum. Although polyclonal antisera from mice immunized with strains of B. japonicum reacted with bacterial cells of all 20 strains, individual monoclonals were more specific. Some antibodies reacted with as few as 2 and one with as many as 11 strains. On the basis of reactivity with the set of 13 monoclonal antibodies, the 20 strains of B. japonicum could be divided arbitrarily into five groups. Three of five monoclonal antibodies tested reacted with bacteroids taken directly from soybean nodules. One monoclonal bound to cells of five species of Rhizobium, but none of the 13 reacted with gram-negative bacteria representing six other genera. Treatment of cells with reagents and heat indicated the chemical nature of the antigens to five of the monoclonals. Antigen reactive with one antibody was destroyed by periodate oxidation indicating that it was a polysaccharide. Two antigens were probably proteins as they could be digested by trypsin and denatured by heat. Two others were inactivated by all three treatments suggesting they were glycoproteins.

Direct preparation of polyfunctional amino-substituted arylmagnesium reagents via an iodine–magnesium exchange reaction

2003 ◽  
pp. 396-397 ◽  
Author(s):  
Greta Varchi ◽  
Christiane Kofink ◽  
David M. Lindsay ◽  
Alfredo Ricci ◽  
Paul Knochel
Keyword(s):  
Exchange Reaction ◽  
Direct Preparation ◽  
Magnesium Exchange
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