A Method for the Determination of the Structure of Saturated Branched-Chain Fatty Acids

1959 ◽  
Vol 12 (4) ◽  
pp. 657 ◽  
Author(s):  
KE Murray

A method is described for the determination of the structure of branched-chain fatty acids. It is found that the carbon chain of methyl-branched acids can be readily degraded by potassium permanganate in acetone, to give a series of acids of decreasing carbon number. Where a branch occurs the acid series is interrupted and a methyl ketone, of the same carbon number as a missing acid, is produced. Gas chromatographic examination of the ketone(s) and esterified acids gives clear evidence for the location of the branch(es). The method is illustrated by application to tuberculostearic acid (10-methyl-octadecanoic acid) and C27-phthianoic acid (2,4,6-trimethyltetracosanoic acid). It appears also able to decide the location of the ring in cyclopropane fatty acids.

2003 ◽  
Vol 2 (3) ◽  
pp. 638-645 ◽  
Author(s):  
Satomi Matsuoka ◽  
Tamao Saito ◽  
Hidekazu Kuwayama ◽  
Naoki Morita ◽  
Hiroshi Ochiai ◽  
...  

ABSTRACT β-Oxidation of long-chain fatty acids and branched-chain fatty acids is carried out in mammalian peroxisomes by a multifunctional enzyme (MFE) or d-bifunctional protein, with separate domains for hydroxyacyl coenzyme A (CoA) dehydrogenase, enoyl-CoA hydratase, and steroid carrier protein SCP2. We have found that Dictyostelium has a gene, mfeA, encoding MFE1 with homology to the hydroxyacyl-CoA dehydrogenase and SCP2 domains. A separate gene, mfeB, encodes MFE2 with homology to the enoyl-CoA hydratase domain. When grown on a diet of bacteria, Dictyostelium cells in which mfeA is disrupted accumulate excess cyclopropane fatty acids and are unable to develop beyond early aggregation. Axenically grown mutant cells, however, developed into normal fruiting bodies composed of spores and stalk cells. Comparative analysis of whole-cell lipid compositions revealed that bacterially grown mutant cells accumulated cyclopropane fatty acids that remained throughout the developmental stages. Such a persistent accumulation was not detected in wild-type cells or axenically grown mutant cells. Bacterial phosphatidylethanolamine that contains abundant cyclopropane fatty acids inhibited the development of even axenically grown mutant cells, while dipalmitoyl phosphatidylethanolamine did not. These results suggest that MFE1 protects the cells from the increase of the harmful xenobiotic fatty acids incorporated from their diets and optimizes cellular lipid composition for proper development. Hence, we propose that this enzyme plays an irreplaceable role in the survival strategy of Dictyostelium cells to form spores for their efficient dispersal in nature.


Nutrients ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1808
Author(s):  
Iris Trefflich ◽  
Stefan Dietrich ◽  
Annett Braune ◽  
Klaus Abraham ◽  
Cornelia Weikert

A vegan diet could impact microbiota composition and bacterial metabolites like short-chain (SCFA) and branched-chain fatty acids (BCFA). The aim of this study was to compare the concentrations of SCFA, BCFA, ammonia, and fecal pH between vegans and omnivores. In this cross-sectional study (vegans n = 36; omnivores n = 36), microbiota composition, fecal SCFA, BCFA, and ammonia concentrations and pH were analyzed in complete stool samples. A random forest regression (RFR) was used to identify bacteria predicting SCFA/BCFA concentrations in vegans and omnivores. No significant differences in SCFA and BCFA concentrations were observed between vegans and omnivores. Fecal pH (p = 0.005) and ammonia concentration (p = 0.01) were significantly lower in vegans than in omnivores, while fiber intake was higher (p < 0.0001). Shannon diversity was higher in omnivores compared to vegans on species level (p = 0.04) only. In vegans, a cluster of Faecalibacterium prausnitzii, Prevotella copri, Dialister spp., and Eubacterium spp. was predictive for SCFA and BCFA concentrations. In omnivores, Bacteroides spp., Clostridium spp., Ruminococcus spp., and Prevotella copri were predictive. Though SCFA and BCFA did not differ between vegans and omnivores, the results of the RFR suggest that bacterial functionality may be adapted to varying nutrient availability in these diets.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jie Shi ◽  
Di Zhao ◽  
Fan Zhao ◽  
Chong Wang ◽  
Galia Zamaratskaia ◽  
...  

AbstractThis study was aimed to evaluate the differences in the composition of gut microbiota, tryptophan metabolites and short-chain fatty acids in feces between volunteers who frequently ate chicken and who frequently ate pork. Twenty male chicken-eaters and 20 male pork-eaters of 18 and 30 years old were recruited to collect feces samples for analyses of gut microbiota composition, short-chain fatty acids and tryptophan metabolites. Chicken-eaters had more diverse gut microbiota and higher abundance of Prevotella 9, Dialister, Faecalibacterium, Megamonas, and Prevotella 2. However, pork-eaters had higher relative abundance of Bacteroides, Faecalibacterium, Roseburia, Dialister, and Ruminococcus 2. In addition, chicken-eaters had high contents of skatole and indole in feces than pork-eaters, as well as higher contents of total short chain fatty acids, in particular for acetic acid, propionic acid, and branched chain fatty acids. The Spearman’s correlation analysis revealed that the abundance of Prevotella 2 and Prevotella 9 was positively correlated with levels of fecal skatole, indole and short-chain fatty acids. Thus, intake of chicken diet may increase the risk of skatole- and indole-induced diseases by altering gut microbiota.


2021 ◽  
pp. 106398
Author(s):  
Peter J. Watkins ◽  
Jerad R. Jaborek ◽  
Fei Teng ◽  
Li Day ◽  
Hardy Z. Castada ◽  
...  

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Béatrice S.-Y. Choi ◽  
Noëmie Daniel ◽  
Vanessa P. Houde ◽  
Adia Ouellette ◽  
Bruno Marcotte ◽  
...  

AbstractAnimal models of human diseases are classically fed purified diets that contain casein as the unique protein source. We show that provision of a mixed protein source mirroring that found in the western diet exacerbates diet-induced obesity and insulin resistance by potentiating hepatic mTORC1/S6K1 signaling as compared to casein alone. These effects involve alterations in gut microbiota as shown by fecal microbiota transplantation studies. The detrimental impact of the mixed protein source is also linked with early changes in microbial production of branched-chain fatty acids (BCFA) and elevated plasma and hepatic acylcarnitines, indicative of aberrant mitochondrial fatty acid oxidation. We further show that the BCFA, isobutyric and isovaleric acid, increase glucose production and activate mTORC1/S6K1 in hepatocytes. Our findings demonstrate that alteration of dietary protein source exerts a rapid and robust impact on gut microbiota and BCFA with significant consequences for the development of obesity and insulin resistance.


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