Modulation of side chain crystallinity in alternating copolymers

2019 ◽  
Vol 10 (48) ◽  
pp. 6588-6599 ◽  
Author(s):  
Sourav Mete ◽  
Krishna Gopal Goswami ◽  
Evgenii Ksendzov ◽  
Sergei V. Kostjuk ◽  
Priyadarsi De
Keyword(s):  
Fatty Acids ◽  
Melting Temperature ◽  
Side Chain ◽  
Alternating Copolymers ◽  
Chain Lengths

A remarkable enhancement in crystalline melting temperature (Tm) was observed in a series of fatty acids and mPEG containing alternating copolymers with the lone increase in mPEG chain lengths.

Bioengineering of emulsifier structure: emulsan analogs

1997 ◽  
Vol 43 (4) ◽  
pp. 384-390 ◽  
Author(s):  
Alexander Gorkovenko ◽  
Jinwen Zhang ◽  
Richard A. Gross ◽  
Alfred L. Allen ◽  
David L. Kaplan
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Carbon Source ◽  
Chain Length ◽  
Acinetobacter Calcoaceticus ◽  
Chain Structure ◽  
Fatty Acid Esters ◽  
Side Chain ◽  
Rag 1 ◽  
Chain Lengths

Strategies were investigated to modulate the side chain structure of emulsans formed by Acinetobacter calcoaceticus RAG-1. Analysis of emulsan fatty acid side chain groups by gas chromatography – mass spectrometry (GC–MS) revealed that by providing the exogenous n-alkanoic fatty acids 15:0, 16:0, and 17:0, emulsan analogs were formed with 53, 46, and 44 mol%, respectively, of fatty acid substituents with chain lengths equal to that of the carbon source. In contrast, the increase in emulsan fatty acids of chain lengths less than 15 or greater than 17 by providing corresponding shorter and longer chain length fatty acids as carbon sources was not substantial. When [1-13C]-labeled (99% enriched) palmitic acid was used as a carbon source along with acetate, analysis of m/z 75/14 and 87/88 isotopomer ratios by GC-MS indicated that 84 and 86% of the 16:0 and 16:1 (9-cis) side groups, respectively, were incorporated intact from the 16:0 carbon source. The percentage of 14-, 15-, 16-, 17-, and 18-carbon chain length fatty acid esters that were monounsaturated were 11, 26, 50, 70, and 85%, respectively. Based on the observed percentage of unsaturated chain length dependence and almost identical enrichment at C-1 of 16:0 and 16:1 (9-cis) side groups from [1-13C]-labeled experiments, it was concluded that desaturation of preformed n-alkanoic acids was the predominant mechanism of their formation. Further work established correlations between side chain structure and product emulsification specificity/activity, so that bioengineered emulsans with improved selectivity can now be formed.Key words: emulsan, Acinetobacter calcoaceticus RAG-1, fatty acids, direct incorporation, emulsification activity.

Side-chain degradation of certain ω-phenoxyalkanecarboxylic acids by Nocardia coeliaca and other micro-organisms isolated from soil

1962 ◽  
Vol 156 (963) ◽  
pp. 172-186 ◽  
Keyword(s):  
Fatty Acids ◽  
Sole Carbon Source ◽  
Oxidation Mechanism ◽  
Caproic Acid ◽  
Culture Technique ◽  
Garden Soil ◽  
Side Chain ◽  
Wheat Coleoptile ◽  
Chain Lengths ◽  
Micro Organisms

Five micro-organisms were isolated from a garden soil by a selective culture technique in which ϵ -(2:4:5-trichlorophenoxy) caproic acid was used as sole carbon source. The capacity of these organisms to degrade the side-chain of certain ω -plienoxyalkanecarboxylic acids C 6 H 5 O(CH 2 ) n COOH was then determined using chromatographic methods for the separation of the products of metabolism. Three of the organisms, viz. Nocardia coeliaca, Pseudo­monas sp. and Micrococcus sp. were found to effect side-chain breakdown readily. All the subsequent investigations here reported were carried out with N. coeliaca. Ten ω -phenoxyalkanecarboxylic acid homologues were incubated with this organism and the chromato­graphic pattern was shown to be consistent with β -oxidation, some hindrance being apparent with shorter chain lengths. In addition, with those homologues containing 9 and 10 methy­lene groups, there was evidence of another type of breakdown which could arise from an α -oxidation mechanism which Stumpf has shown to operate with fatty acids of a certain chain length. Phenol was not detected in metabolized solutions of any of the phenoxy homologues. The cells of the organism, however, which had been incubated with the pro­pionic, valeric or heptanoic acids ( n = 2, 4 or 6), i. e. those acids theoretically able to yield phenol by β -oxidation, were found to have an increased capacity for metabolizing phenol. It was therefore concluded that phenol is, in fact, produced in the metabolism of these phenoxy acids by N. coeliaca. Metabolism experiments were also carried out with members of six homologous series of chloro-substituted phenoxyalkanecarboxylic acids. The corresponding phenol was estimated in solutions after metabolism in each case and the results were readily explicable in terms of β -oxidation of the side-chain. The breakdown patterns on chromatograms were also typical of this type 'of oxidation. Certain types of ring substitution were shown to hinder β -oxidation in a manner to that found in our earlier investigations in which wheat coleoptile and pea stem tissues were used.

scholarly journals Anaerobic 1-Alkene Metabolism by the Alkane- and Alkene-Degrading Sulfate Reducer Desulfatibacillum aliphaticivorans Strain CV2803T

2007 ◽  
Vol 73 (24) ◽  
pp. 7882-7890 ◽  
Author(s):  
Vincent Grossi ◽  
Cristiana Cravo-Laureau ◽  
Alain Méou ◽  
Danielle Raphel ◽  
Frédéric Garzino ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Inorganic Carbon ◽  
Direct Evidence ◽  
Gas Chromatography Mass Spectrometry ◽  
Sulfate Reducing ◽  
Branched Fatty Acids ◽  
Initial Activation ◽  
Fumarate Addition ◽  
Chain Lengths ◽  
Methyl Branched Fatty Acids

ABSTRACT The alkane- and alkene-degrading, marine sulfate-reducing bacterium Desulfatibacillum aliphaticivorans strain CV2803T, known to oxidize n-alkanes anaerobically by fumarate addition at C-2, was investigated for its 1-alkene metabolism. The total cellular fatty acids of this strain were predominantly C-(even number) (C-even) when it was grown on C-even 1-alkenes and predominantly C-(odd number) (C-odd) when it was grown on C-odd 1-alkenes. Detailed analyses of those fatty acids by gas chromatography-mass spectrometry after 6- to 10-week incubations allowed the identification of saturated 2- and 4-ethyl-, 2- and 4-methyl-, and monounsaturated 4-methyl-branched fatty acids with chain lengths that correlated with those of the 1-alkene. The growth of D. aliphaticivorans on (per)deuterated 1-alkenes provided direct evidence of the anaerobic transformation of these alkenes into the corresponding 1-alcohols and into linear as well as 10- and 4-methyl-branched fatty acids. Experiments performed with [13C]bicarbonate indicated that the initial activation of 1-alkene by the addition of inorganic carbon does not occur. These results demonstrate that D. aliphaticivorans metabolizes 1-alkene by the oxidation of the double bond at C-1 and by the subterminal addition of organic carbon at both ends of the molecule [C-2 and C-(ω-1)]. The detection of ethyl-branched fatty acids from unlabeled 1-alkenes further suggests that carbon addition also occurs at C-3. Alkylsuccinates were not observed as potential initial intermediates in alkene metabolism. Based on our observations, the first pathways for anaerobic 1-alkene metabolism in an anaerobic bacterium are proposed. Those pathways indicate that diverse initial reactions of 1-alkene activation can occur simultaneously in the same strain of sulfate-reducing bacterium.

Pyridine-based poly(aryleneethynylene)s: a study on anionic side chain density and their influence on optical properties and metallochromicity

RSC Advances ◽  
2015 ◽  
Vol 5 (116) ◽  
pp. 96189-96193 ◽  
Author(s):  
Markus Bender ◽  
Kai Seehafer ◽  
Marlene Findt ◽  
Uwe H. F. Bunz
Keyword(s):  
Optical Properties ◽  
Water Soluble ◽  
Side Chain ◽  
Phenylene Ethynylene ◽  
Alternating Copolymers

We report the Pd-catalyzed synthesis of six new water soluble, alternating poly(p-phenylene-ethynylene-p-pyridinylene-ethynylene) (abcb-alternating) copolymers and one poly(p-pyridinyleneethynylene).

scholarly journals Lack of activation of UCP1 in isolated brown adipose tissue mitochondria by glucose-O-ω-modified saturated fatty acids of various chain lengths

2013 ◽  
Vol 6 (3) ◽  
pp. 121-133 ◽  
Author(s):  
Eamon P. Breen ◽  
Wayne Pilgrim ◽  
Kieran J. Clarke ◽  
Cristy Yssel ◽  
Mark Farrell ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Saturated Fatty Acids ◽  
Brown Adipose ◽  
Chain Lengths
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