scholarly journals Beta Hydroxylation of Glycolipids from Ustilago maydis and Pseudozyma flocculosa by an NADPH-Dependent β-Hydroxylase

2011 ◽  
Vol 77 (21) ◽  
pp. 7823-7829 ◽  
Author(s):  
Beate Teichmann ◽  
François Lefebvre ◽  
Caroline Labbé ◽  
Michael Bölker ◽  
Uwe Linne ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Short Chain Fatty Acid ◽  
Ustilago Maydis ◽  
Chain Fatty Acid ◽  
Amino Acid Sequences ◽  
Short Chain ◽  
Hydroxyl Group ◽  
Content Type ◽  
Pseudozyma Flocculosa ◽  
Cellobiose Lipids

ABSTRACTFlocculosin and ustilagic acid (UA), two highly similar antifungal cellobiose lipids, are respectively produced byPseudozyma flocculosa, a biocontrol agent, andUstilago maydis, a plant pathogen. Both glycolipids contain a short-chain fatty acid hydroxylated at the β position but differ in the long fatty acid, which is hydroxylated at the α position in UA and at the β position in flocculosin. In both organisms, the biosynthesis genes are arranged in large clusters. The functions of most genes have already been characterized, but those of theP. flocculosa fhd1gene and its homolog fromU. maydis,uhd1, have remained undefined. The deduced amino acid sequences of these genes show homology to those of short-chain dehydrogenases and reductases (SDR). We disrupted theuhd1gene inU. maydisand analyzed the secreted UA.uhd1deletion strains produced UA lacking the β-hydroxyl group of the short-chain fatty acid. To analyze the function ofP. flocculosaFhd1, the corresponding gene was used to complementU. maydisΔuhd1mutants. Fhd1 was able to restore wild-type UA production, indicating that Fhd1 is responsible for β hydroxylation of the flocculosin short-chain fatty acid. We also investigated aP. flocculosahomolog of theU. maydislong-chain fatty-acid alpha hydroxylase Ahd1. TheP. flocculosa ahd1gene, which does not reside in the flocculosin gene cluster, was introduced intoU. maydisΔahd1mutant strains.P. flocculosaAhd1 neither complemented theU. maydisΔahd1phenotype nor resulted in the production of β-hydroxylated UA. This suggests thatP. flocculosaAhd1 is not involved in flocculosin hydroxylation.

scholarly journals In VitroFermentation of Linear and α-1,2-Branched Dextrans by the Human Fecal Microbiota

2011 ◽  
Vol 77 (15) ◽  
pp. 5307-5315 ◽  
Author(s):  
Shahrul R. Sarbini ◽  
Sofia Kolida ◽  
Thierry Naeye ◽  
Alexandra Einerhand ◽  
Yoann Brison ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Short Chain Fatty Acid ◽  
Short Chain Fatty Acids ◽  
Fecal Microbiota ◽  
Gas Production ◽  
Chain Fatty Acid ◽  
Short Chain ◽  
Content Type ◽  
Bacterial Enumeration ◽  
Ph Controlled

ABSTRACTThe role of structure and molecular weight in fermentation selectivity in linear α-1,6 dextrans and dextrans with α-1,2 branching was investigated. Fermentation by gut bacteria was determined in anaerobic, pH-controlled fecal batch cultures after 36 h. Inulin (1%, wt/vol), which is a known prebiotic, was used as a control. Samples were obtained at 0, 10, 24, and 36 h of fermentation for bacterial enumeration by fluorescentin situhybridization and short-chain fatty acid analyses. The gas production of the substrate fermentation was investigated in non-pH-controlled, fecal batch culture tubes after 36 h. Linear and branched 1-kDa dextrans produced significant increases inBifidobacteriumpopulations. The degree of α-1,2 branching did not influence theBifidobacteriumpopulations; however, α-1,2 branching increased the dietary fiber content, implying a decrease in digestibility. Other measured bacteria were unaffected by the test substrates except for theBacteroides-Prevotellagroup, the growth levels of which were increased on inulin and 6- and 70-kDa dextrans, and theFaecalibacterium prausnitziigroup, the growth levels of which were decreased on inulin and 1-kDa dextrans. A considerable increase in short-chain fatty acid concentration was measured following the fermentation of all dextrans and inulin. Gas production rates were similar among all dextrans tested but were significantly slower than that for inulin. The linear 1-kDa dextran produced lower total gas and shorter time to attain maximal gas production compared to those of the 70-kDa dextran (branched) and inulin. These findings indicate that dextrans induce a selective effect on the gut flora, short-chain fatty acids, and gas production depending on their length.

scholarly journals Functional Screening andIn VitroAnalysis Reveal Thioesterases with Enhanced Substrate Specificity Profiles That Improve Short-Chain Fatty Acid Production in Escherichia coli

2013 ◽  
Vol 80 (3) ◽  
pp. 1042-1050 ◽  
Author(s):  
Matthew D. McMahon ◽  
Kristala L. J. Prather
Keyword(s):  
Escherichia Coli ◽  
Fatty Acid ◽  
Substrate Specificity ◽  
Short Chain Fatty Acid ◽  
Chain Fatty Acid ◽  
Short Chain ◽  
Functional Screening ◽  
Acetyl Coa ◽  
Content Type

ABSTRACTShort-chain fatty acid (SCFA) biosynthesis is pertinent to production of biofuels, industrial compounds, and pharmaceuticals from renewable resources. To expand onEscherichia coliSCFA products, we previously implemented a coenzyme A (CoA)-dependent pathway that condenses acetyl-CoA to a diverse group of short-chain fatty acyl-CoAs. To increase product titers and reduce premature pathway termination products, we conductedin vivoandin vitroanalyses to understand and improve the specificity of the acyl-CoA thioesterase enzyme, which releases fatty acids from CoA. A total of 62 putative bacterial thioesterases, including 23 from the cow rumen microbiome, were inserted into a pathway that condenses acetyl-CoA to an acyl-CoA molecule derived from exogenously provided propionic or isobutyric acid. Functional screening revealed thioesterases that increase production of saturated (valerate), unsaturated (trans-2-pentenoate), and branched (4-methylvalerate) SCFAs compared to overexpression ofE. colithioesterasetesBor native expression of endogenous thioesterases. To determine if altered thioesterase acyl-CoA substrate specificity caused the increase in product titers, six of the most promising enzymes were analyzedin vitro. Biochemical assays revealed that the most productive thioesterases rely on promiscuous activity but have greater specificity for product-associated acyl-CoAs than for precursor acyl-CoAs. In this study, we introduce novel thioesterases with improved specificity for saturated, branched, and unsaturated short-chain acyl-CoAs, thereby expanding the diversity of potential fatty acid products while increasing titers of current products. The growing uncertainty associated with protein database annotations denotes this study as a model for isolating functional biochemical pathway enzymes in situations where experimental evidence of enzyme function is absent.

l-Theanine affects intestinal mucosal immunity by regulating short-chain fatty acid metabolism under dietary fiber feeding

2020 ◽  
Vol 11 (9) ◽  
pp. 8369-8379
Author(s):  
Wei Xu ◽  
Ling Lin ◽  
An Liu ◽  
Tuo Zhang ◽  
Sheng Zhang ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Dietary Fiber ◽  
Fatty Acid Metabolism ◽  
Mucosal Immunity ◽  
Cholesterol Synthesis ◽  
Short Chain Fatty Acid ◽  
Acid Metabolism ◽  
Chain Fatty Acid ◽  
Short Chain

LTA regulates SCFA metabolism and improves intestinal mucosal immunity by improving cholesterol synthesis in the liver and inhibiting gluconeogenesis in the colon.

scholarly journals Influence of Supplementation of Lactoferrin, Melittin and Cecropin A to Rat Diet on Changes in Faecal Ammonia Concentrations, Short-Chain Fatty Acid Concentrations and Activities of Bacterial Enzymes

Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1203
Author(s):  
Jerzy Juśkiewicz ◽  
Aleksandra Rawicka ◽  
Bartosz Fotschki ◽  
Michał Majewski ◽  
Zenon Zduńczyk
Keyword(s):  
Fatty Acid ◽  
Short Chain Fatty Acid ◽  
Control Diet ◽  
Chain Fatty Acid ◽  
Short Chain ◽  
Antimicrobial Protein ◽  
Enzyme Release ◽  
Bacterial Cells ◽  
Suppression Effect ◽  
Cecropin A

We hypothesised that the dietary addition of the bioactive antimicrobial protein lactoferrin (LF) and peptides melittin (MT) or cecropin A (CR) at a dosage of 100 mg/kg to the diet of Wistar rats would result in strong modulatory effects on faecal microbial enzymatic activity, short-chain fatty acid and ammonia concentrations. To date, the changes in bacterial extracellular and intracellular enzymatic activities upon addition of dietary AMPs have not yet been studied. This experiment lasted 15 days; during the first 5 day period, the rats were fed the control diet (S) and diets supplemented with LF, MT or CR. On days 6–15, all rats were fed the control S diet. The faecal fermentation processes were substantially stopped after two days of treatment, on average, in all rats receiving LF and two AMPs. The deepest suppression effect was observed on the last day of treatment (day 5) and persisted through days 5–8. The highest decreases in faecal bacterial β-glucosidase and β-glucuronidase activities as well as in SCFA and ammonia concentrations were observed in the rats fed the CR diet. Only in the CR animals did the mechanism of suppressed microbial fermentation involve diminished enzyme release from bacterial cells to the digesta.

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