Статті в журналах: "Cyclopropane fatty acids (CFA)"

1

Saborido Basconcillo, Libia, Rahat Zaheer, Turlough M. Finan, and Brian E. McCarry. "Cyclopropane fatty acyl synthase in Sinorhizobium meliloti." Microbiology 155, no. 2 (February 1, 2009): 373–85. http://dx.doi.org/10.1099/mic.0.022608-0.

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Cyclopropane fatty acyl synthases (CFA synthases) are enzymes that catalyse the addition of a methylene group across cis double bonds of monounsaturated fatty acyl chains in lipids. We have investigated the function of two putative genes, cfa1 and cfa2, proposed to code for CFA synthases in Sinorhizobium meliloti. Total fatty acid composition and fatty acid distributions within lipid classes for wild-type and cfa1 and cfa2 mutant strains grown under Pi starvation and in acidic culture conditions were obtained by GC/MS and by infusion ESI/MS/MS, respectively. For wild-type cells and the cfa1 mutant, total cyclopropane fatty acids (CFAs) increased by 10 % and 15 % under Pi starvation and acidic conditions, respectively; whereas in the cfa2 mutant, CFAs were less than 0.1 % of wild-type under both growth conditions. Reporter gene fusion experiments revealed that cfa1 and cfa2 were expressed at similar levels in free-living cells. Thus under the conditions we examined, cfa2 was required for the cyclopropanation of lipids in S. meliloti whereas the role of cfa1 remains to be determined. Analysis of intact lipids revealed that cyclopropanation occurred on cis-11-octadecenoic acid located in either the sn-1 or the sn-2 position in phospholipids and that cyclopropanation in the sn-2 position occurred to a greater extent in phosphatidylcholines and sulfoquinovosyldiacylglycerols under acidic conditions than under Pi starvation. The cfa2 gene was also required for cyclopropanation of non-phosphorus-containing lipids. Principal components analysis revealed no differences in the cyclopropanation of four lipid classes. We concluded that cyclopropanation occurred independently of the polar head group. Neither cfa1 nor cfa2 was required for symbiotic nitrogen fixation.

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2

Kim, Bae Hoon, Seungki Kim, Hyeon Guk Kim, Jin Lee, In Soo Lee, and Yong Keun Park. "The formation of cyclopropane fatty acids in Salmonella enterica serovar Typhimurium." Microbiology 151, no. 1 (January 1, 2005): 209–18. http://dx.doi.org/10.1099/mic.0.27265-0.

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The formation of cyclopropane fatty acid (CFA) and its role in the acid shock response in Salmonella enterica serovar Typhimurium (S. typhimurium) was investigated. Data obtained by GC/MS demonstrated that the CFA level in S. typhimurium increased upon its entry to the stationary phase, as in other bacteria. The cfa gene encoding CFA synthase was cloned, and mutants of the cfa gene were constructed by allelic exchange. A cfa mutant could not produce CFA and was sensitive to low pH. Introduction of a functional cfa gene into a cfa mutant cell made the mutant convert all unsaturated fatty acids to CFAs and partially restored resistance to low pH. Interestingly, the alternative sigma factor RpoS, which was induced during the stationary phase, affected the production of C19 CFA but not C17 CFA. Western blotting analysis showed that the increase in expression of CFA synthase at early stationary phase was due to the alternative sigma factor RpoS.

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3

Grogan, D. W., and J. E. Cronan. "Cyclopropane ring formation in membrane lipids of bacteria." Microbiology and Molecular Biology Reviews 61, no. 4 (December 1997): 429–41. http://dx.doi.org/10.1128/mmbr.61.4.429-441.1997.

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It has been known for several decades that cyclopropane fatty acids (CFAs) occur in the phospholipids of many species of bacteria. CFAs are formed by the addition of a methylene group, derived from the methyl group of S-adenosylmethionine, across the carbon-carbon double bond of unsaturated fatty acids (UFAs). The C1 transfer does not involve free fatty acids or intermediates of phospholipid biosynthesis but, rather, mature phospholipid molecules already incorporated into membrane bilayers. Furthermore, CFAs are typically produced at the onset of the stationary phase in bacterial cultures. CFA formation can thus be considered a conditional, postsynthetic modification of bacterial membrane lipid bilayers. This modification is noteworthy in several respects. It is catalyzed by a soluble enzyme, although one of the substrates, the UFA double bond, is normally sequestered deep within the hydrophobic interior of the phospholipid bilayer. The enzyme, CFA synthase, discriminates between phospholipid vesicles containing only saturated fatty acids and those containing UFAs; it exhibits no affinity for vesicles of the former composition. These and other properties imply that topologically novel protein-lipid interactions occur in the biosynthesis of CFAs. The timing and extent of the UFA-to-CFA conversion in batch cultures and the widespread distribution of CFA synthesis among bacteria would seem to suggest an important physiological role for this phenomenon, yet its rationale remains unclear despite experimental tests of a variety of hypotheses. Manipulation of the CFA synthase of Escherichia coli by genetic methods has nevertheless provided valuable insight into the physiology of CFA formation. It has identified the CFA synthase gene as one of several rpoS-regulated genes of E. coli and has provided for the construction of strains in which proposed cellular functions of CFAs can be properly evaluated. Cloning and manipulation of the CFA synthase structural gene have also enabled this novel but extremely unstable enzyme to be purified and analyzed in molecular terms and have led to the identification of mechanistically related enzymes in clinically important bacterial pathogens.

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Ma, Yulong, Chunli Pan, and Qihai Wang. "Crystal structure of bacterial cyclopropane-fatty-acyl-phospholipid synthase with phospholipid." Journal of Biochemistry 166, no. 2 (March 4, 2019): 139–47. http://dx.doi.org/10.1093/jb/mvz018.

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AbstractThe lipids containing cyclopropane-fatty-acid (CFA) protect bacteria from adverse conditions such as acidity, freeze-drying desiccation and exposure to pollutants. CFA is synthesized when cyclopropane-fatty-acyl-phospholipid synthase (CFA synthase, CFAS) transfers a methylene group from S-adenosylmethionine (SAM) across the cis double bonds of unsaturated fatty acyl chains. Here, we reported a 2.7-Å crystal structure of CFAS from Lactobacillus acidophilus. The enzyme is composed of N- and C-terminal domain, which belong to the sterol carrier protein and methyltransferase superfamily, respectively. A phospholipid in the substrate binding site and a bicarbonate ion (BCI) acting as a general base in the active site were discovered. To elucidate the mechanism, a docking experiment using CFAS from L. acidophilus and SAM was carried out. The analysis of this structure demonstrated that three groups, the carbons from the substrate, the BCI and the methyl of S(CHn)3 group, were close enough to form a cyclopropane ring with the help of amino acids in the active site. Therefore, the structure supports the hypothesis that CFAS from L. acidophilus catalyzes methyl transfer via a carbocation mechanism. These findings provide a structural basis to more deeply understand enzymatic cyclopropanation.

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5

Chang, Ying-Ying, Johannes Eichel, and John E. Cronan. "Metabolic Instability of Escherichia coli Cyclopropane Fatty Acid Synthase Is Due to RpoH-Dependent Proteolysis." Journal of Bacteriology 182, no. 15 (August 1, 2000): 4288–94. http://dx.doi.org/10.1128/jb.182.15.4288-4294.2000.

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ABSTRACT Cyclopropane fatty acids (CFAs) are generally synthesized as bacterial cultures enter stationary phase. In Escherichia coli, the onset of CFA synthesis results from increased transcription of cfa, the gene encoding CFA synthase. However, the increased level of CFA synthase activity is transient; the activity quickly declines to the basal level. We report that the loss of CFA activity is due to proteolytic degradation dependent on expression of the heat shock regulon. CFA synthase degradation is unaffected by mutations in the lon, clpP, andgroEL genes or by depletion of the intracellular ATP pools. It seems likely that CFA synthase is the target of an unidentified energy-independent heat shock regulon protease. This seems to be the first example of heat shock-dependent degradation of a normal biosynthetic enzyme.

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6

Kanno, Manabu, Taiki Katayama, Hideyuki Tamaki, Yasuo Mitani, Xian-Ying Meng, Tomoyuki Hori, Takashi Narihiro, et al. "Isolation of Butanol- and Isobutanol-Tolerant Bacteria and Physiological Characterization of Their Butanol Tolerance." Applied and Environmental Microbiology 79, no. 22 (September 6, 2013): 6998–7005. http://dx.doi.org/10.1128/aem.02900-13.

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ABSTRACTDespite their importance as a biofuel production platform, only a very limited number of butanol-tolerant bacteria have been identified thus far. Here, we extensively explored butanol- and isobutanol-tolerant bacteria from various environmental samples. A total of 16 aerobic and anaerobic bacteria that could tolerate greater than 2.0% (vol/vol) butanol and isobutanol were isolated. A 16S rRNA gene sequencing analysis revealed that the isolates were phylogenetically distributed over at least nine genera:Bacillus,Lysinibacillus,Rummeliibacillus,Brevibacillus,Coprothermobacter,Caloribacterium,Enterococcus,Hydrogenoanaerobacterium, andCellulosimicrobium, within the phylaFirmicutesandActinobacteria. Ten of the isolates were phylogenetically distinct from previously identified butanol-tolerant bacteria. Two relatively highly butanol-tolerant strains CM4A (aerobe) and GK12 (obligate anaerobe) were characterized further. Both strains changed their membrane fatty acid composition in response to butanol exposure, i.e., CM4A and GK12 exhibited increased saturated and cyclopropane fatty acids (CFAs) and long-chain fatty acids, respectively, which may serve to maintain membrane fluidity. The gene (cfa) encoding CFA synthase was cloned from strain CM4A and expressed inEscherichia coli. The recombinantE. colishowed relatively higher butanol and isobutanol tolerance thanE. coliwithout thecfagene, suggesting thatcfacan confer solvent tolerance. The exposure of strain GK12 to butanol by consecutive passages even enhanced the growth rate, indicating that yet-unknown mechanisms may also contribute to solvent tolerance. Taken together, the results demonstrate that a wide variety of butanol- and isobutanol-tolerant bacteria that can grow in 2.0% butanol exist in the environment and have various strategies to maintain structural integrity against detrimental solvents.

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7

Zhao, Yinsuo, Lucia A. Hindorff, Amy Chuang, Melanie Monroe-Augustus, Michael Lyristis, Mary L. Harrison, Frederick B. Rudolph, and George N. Bennett. "Expression of a Cloned Cyclopropane Fatty Acid Synthase Gene Reduces Solvent Formation in Clostridium acetobutylicum ATCC 824." Applied and Environmental Microbiology 69, no. 5 (May 2003): 2831–41. http://dx.doi.org/10.1128/aem.69.5.2831-2841.2003.

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ABSTRACT The cyclopropane fatty acid synthase gene (cfa) of Clostridium acetobutylicum ATCC 824 was cloned and overexpressed under the control of the clostridial ptb promoter. The function of the cfa gene was confirmed by complementation of an Escherichia coli cfa-deficient strain in terms of fatty acid composition and growth rate under solvent stress. Constructs expressing cfa were introduced into C. acetobutylicum hosts and cultured in rich glucose broth in static flasks without pH control. Overexpression of the cfa gene in the wild type and in a butyrate kinase-deficient strain increased the cyclopropane fatty acid content of early-log-phase cells as well as initial acid and butanol resistance. However, solvent production in the cfa-overexpressing strain was considerably decreased, while acetate and butyrate levels remained high. The findings suggest that overexpression of cfa results in changes in membrane properties that dampen the full induction of solventogenesis. The overexpression of a marR homologous gene preceding the cfa gene in the clostridial genome resulted in reduced cyclopropane fatty acid accumulation.

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8

Lolli, Veronica, Daniele Del Rio, and Augusta Caligiani. "Cyclopropane fatty acids in foods." INFORM International News on Fats, Oils, and Related Materials 30, no. 4 (April 1, 2019): 18–22. http://dx.doi.org/10.21748/inform.04.2019.18.

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9

Eichel, Johannes, Ying-Ying Chang, Dieter Riesenberg та John E. Cronan. "Effect of ppGpp on Escherichia coliCyclopropane Fatty Acid Synthesis Is Mediated through the RpoS Sigma Factor (ςS)". Journal of Bacteriology 181, № 2 (15 січня 1999): 572–76. http://dx.doi.org/10.1128/jb.181.2.572-576.1999.

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ABSTRACT Strains of Escherichia coli carrying mutations at therelA locus are deficient in cyclopropane fatty acid (CFA) synthesis, a phospholipid modification that occurs as cultures enter stationary phase. RelA protein catalyzes the synthesis of guanosine-3′,5′-bisdiphosphate (ppGpp); therefore, ppGpp was a putative direct regulator of CFA synthesis. The nucleotide could act by increasing either the activity or the amount of CFA synthase, the enzyme catalyzing the lipid modification. We report that the effect of RelA on CFA synthesis is indirect. In vitro and in vivo experiments show no direct interaction between ppGpp and CFA synthase activity. TherelA effect is due to ppGpp-engendered stimulation of the synthesis of the alternative sigma factor, RpoS, which is required for function of one of the two promoters responsible for expression of CFA synthase.

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10

Härtig, Claus, Norbert Loffhagen, and Hauke Harms. "Formation of trans Fatty Acids Is Not Involved in Growth-Linked Membrane Adaptation of Pseudomonas putida." Applied and Environmental Microbiology 71, no. 4 (April 2005): 1915–22. http://dx.doi.org/10.1128/aem.71.4.1915-1922.2005.

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ABSTRACT Fatty acid compositions in growing and resting cells of several strains of Pseudomonas putida (P8, NCTC 10936, and KT 2440) were studied, with a focus on alterations of the saturation degree, cis-trans isomerization, and cyclopropane formation. The fatty acid compositions of the strains were very similar under comparable growth conditions, but surprisingly, and contrary to earlier reports, trans fatty acids were not found in either exponentially growing cells or stationary-phase cells. During the transition from growth to the starvation state, cyclopropane fatty acids were preferentially formed, an increase in the saturation degree of fatty acids was observed, and larger amounts of hydroxy fatty acids were detected. A lowered saturation degree and concomitant higher membrane fluidity seemed to be optimal for substrate uptake and growth. The incubation of cells under nongrowth conditions rapidly led to the formation of trans fatty acids. We show that harvesting and sample preparation for analysis could provoke the enzyme-catalyzed formation of trans fatty acids. Freeze-thawing of resting cells and increased temperatures accelerated the formation of trans fatty acids. We demonstrate that cis-trans isomerization only occurred in cells that were subjected to an abrupt disturbance without having the possibility of adapting to the changed conditions by the de novo synthesis of fatty acids. The cis-trans isomerization reaction was in competition with the cis-to-cyclopropane fatty acid conversion. The potential for the formation of trans fatty acids depended on the cyclopropane content that was already present.

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Lolli, Veronica, Angela Marseglia, Gerardo Palla, Emanuela Zanardi, and Augusta Caligiani. "Determination of Cyclopropane Fatty Acids in Food of Animal Origin by 1H NMR." Journal of Analytical Methods in Chemistry 2018 (2018): 1–8. http://dx.doi.org/10.1155/2018/8034042.

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Cyclopropane fatty acids (CPFAs) are unusual fatty acids of microbial origin, recently detected in milk and dairy products. CPFAs have been demonstrated to be interesting molecular markers for authentication of dairy products obtained without ensiled feeds. Moreover, they can also be recognized as a new secondary component of human diet. Information is lacking on the presence of cyclic fatty acids in other food sources. Cyclopropane fatty acids have been detected by GC-MS analysis in cheese and other animal fats in concentration ranging from 200 to 1000 mg/kg fat, but in some cases, the complex fatty acid profile and the possible presence of interfering peaks make the separation not straightforward and the quantification uneasy. Therefore, a new reliable 1H NMR method was developed to detect and measure CPFA content in different foods of animal origin, based on the detection of the characteristic signals of cyclopropane ring. The 1H NMR (600 MHz) method showed detection limits comparable with those of full scan GC-MS, and it allowed the identification and quantitation of the cyclopropane fatty acids in different foods.

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12

Machida, Shuntaro, Yoshihiro Shiraiwa, and Iwane Suzuki. "Construction of a cyanobacterium synthesizing cyclopropane fatty acids." Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids 1861, no. 9 (September 2016): 980–87. http://dx.doi.org/10.1016/j.bbalip.2016.05.012.

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13

Chao, Jerry, Gideon M. Wolfaardt, and Michael T. Arts. "Characterization of Pseudomonas aeruginosa fatty acid profiles in biofilms and batch planktonic cultures." Canadian Journal of Microbiology 56, no. 12 (December 2010): 1028–39. http://dx.doi.org/10.1139/w10-093.

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The fatty acid composition of Pseudomonas aeruginosa PAO1 was compared between biofilm and batch planktonic cultures. Strain PAO1 biofilms were able to maintain a consistent fatty acid profile for up to 6 days, whereas strain PAO1 batch planktonic cultures showed a gradual loss of cis-monounsaturated fatty acids over 4 days. Biofilms exhibited a greater proportion of hydroxy fatty acids but a lower proportion of both cyclopropane fatty acids and saturated fatty acids (SAFAs). SAFAs with ≥16 carbons, in particular, decreased in biofilms when compared with that in batch planktonic cultures. A reduced proportion of SAFAs and a decline in overall fatty acid chain length indicate more fluidic biophysical properties for cell membranes of P. aeruginosa in biofilms. Separating the biofilms into 2 partitions and comparing their fatty acid compositions revealed additional trends that were not observed in the whole biofilm: the shear-nonremovable layer consistently showed greater proportions of hydroxy fatty acid than the bulk liquid + shear-removable portion of the biofilm. The shear-nonremovable portion demonstrated a relatively immediate decline in the proportion of monounsaturated fatty acids between days 2 and 4; which was offset by an increase in the proportion of cyclopropane fatty acids, specifically 19:0cyc(11,12). Simultaneously, the shear-removable portion of the biofilm showed an increase in the proportion of trans-monounsaturated fatty acids and cyclopropane fatty acids.

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Inuki, Shinsuke, Ippei Ohta, Shunichi Ishibashi, Masayuki Takamatsu, Koichi Fukase, and Yukari Fujimoto. "Total Synthesis of Cardiolipins Containing Chiral Cyclopropane Fatty Acids." Journal of Organic Chemistry 82, no. 15 (July 19, 2017): 7832–38. http://dx.doi.org/10.1021/acs.joc.7b00945.

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15

Białek, Agnieszka, Małgorzata Białek, Tomasz Lepionka, Małgorzata Czerwonka, and Marian Czauderna. "Chemometric Analysis of Fatty Acids Profile of Ripening Chesses." Molecules 25, no. 8 (April 15, 2020): 1814. http://dx.doi.org/10.3390/molecules25081814.

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The number of different types of cheese worldwide exceeds 4000 and dairy fat, composed of about 400 fatty acids (FA), is one of the most complex dietary fats. Cheeses are valuable sources of different bioactive FA, i.e., conjugated FA (CFA). The aim of present study was to determine FA profile of commercially available ripening cheeses, with the special emphasis on CFA profile. Multivariate analyses (cluster analysis (CA), principal component Analysis (PCA), and linear discriminant analysis (LDA)) of chromatographic data have been proposed as an objective approach for evaluation and data interpretation. CA enabled the differentiation of ripening cheeses from fresh cheeses and processed cheeses. PCA allowed to differentiate some types of ripening cheese whereas proposed LDA model, based on 22 analyzed FA, enabled assessing cheeses type with average predictive sensitivities of 86.5%. Results of present study clearly demonstrated that FA and CFA content may not only contribute to overall nutritional characteristics of cheese but also, when coupled with chemometric techniques, may be used as chemical biomarkers for assessing the origin and/or the type of ripening cheeses and the confirmation of their authenticity, which is of utmost importance for consumers.

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Matsuoka, Satomi, Tamao Saito, Hidekazu Kuwayama, Naoki Morita, Hiroshi Ochiai, and Mineko Maeda. "MFE1, a Member of the Peroxisomal Hydroxyacyl Coenzyme A Dehydrogenase Family, Affects Fatty Acid Metabolism Necessary for Morphogenesis in Dictyostelium spp." Eukaryotic Cell 2, no. 3 (June 2003): 638–45. http://dx.doi.org/10.1128/ec.2.3.638-645.2003.

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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.

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Goldschmidt, Robert, and William Byrdwell. "GC Analysis of Seven Seed Oils Containing Conjugated Fatty Acids." Separations 8, no. 4 (April 15, 2021): 51. http://dx.doi.org/10.3390/separations8040051.

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The fatty acid compositions, including isomer compositions, of seven seed oils containing conjugated fatty acids (CFA) were determined. Seed oils were extracted using a modified Folch extraction, converted to fatty acid methyl esters, and analyzed by gas chromatography (GC) with mass spectrometry and flame ionization detection. The MS detector was operated in positive-ion chemical ionization mode using methane reagent gas. GC was performed using two columns providing different retention characteristics: a poly(ethylene glycol) column and a more polar biscyanopropyl column. The complimentary information provided by the two columns was crucial to peak identification in several cases. The major CFA species in the samples are well known but all contained lesser amounts of additional CFA that have not been widely reported. All samples contained multiple species of conjugated linolenic acid, and two samples also contained small amounts of conjugated linoleic acid. The seed oils of Jacaranda mimosifolia and Calendula officinalis were found to contain 8c,10t,12t-18:3, the natural occurrence of which has only been recently reported in some other samples. The seed oil of Impatiens balsamina has been reported to contain four conjugated 18:4 species, and we present evidence for a fifth conjugated 18:4 isomer.

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Kim, Gwang-Woo, Jae-Man Sim, Yutaka Itabashi, Min-Jeong Jung, and Joon-Young Jun. "Occurrence of Cis-11,12-Methylene-Hexadecanoic Acid in the Red Alga Solieria pacifica (Yamada) Yoshida." Molecules 26, no. 8 (April 15, 2021): 2286. http://dx.doi.org/10.3390/molecules26082286.

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Fatty acids in marine algae have attracted the attention of natural chemists because of their biological activity. The fatty acid compositions of the Solieriaceae families (Rhodophyceae, Gaigartinales) provide interesting information that unusual cyclic fatty acids have been occasionally found. A survey was conducted to profile the characteristic fatty acid composition of the red alga Solieria pacifica (Yamada) Yoshida using gas chromatography-mass spectrometry (GC-MS), infrared spectroscopy (IR), and proton nuclear magnetic resonance spectroscopy (1H-NMR). In S. pacifica, two cyclopentyl fatty acids, 11-cyclopentylundecanoic acid (7.0%), and 13-cyclopentyltridecanoic acid (4.9%), and a cyclopropane fatty acid, cis-11,12-methylene-hexadecanoic acid (7.9%) contributed significantly to the overall fatty acid profile. In particular, this cyclopropane fatty acid has been primarily found in bacteria, rumen microorganisms or foods of animal origin, and has not previously been found in any other algae. In addition, this alga contains a significant amount of the monoenoic acid cis-11-hexadecenoic acid (9.0%). Therefore, cis-11,12-methylene-hexadecanoic acid in S. pacifica was likely produced by methylene addition to cis-11-hexadecenoic acid.

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Muñoz-Rojas, Jesús, Patricia Bernal, Estrella Duque, Patricia Godoy, Ana Segura, and Juan-Luis Ramos. "Involvement of Cyclopropane Fatty Acids in the Response of Pseudomonas putida KT2440 to Freeze-Drying." Applied and Environmental Microbiology 72, no. 1 (January 2006): 472–77. http://dx.doi.org/10.1128/aem.72.1.472-477.2006.

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ABSTRACT Pseudomonas putida KT2440, a saprophytic soil bacterium that colonizes the plant root, is a suitable microorganism for the removal of pollutants and a stable host for foreign genes used in biotransformation processes. Because of its potential use in agriculture and industry, we investigated the conditions for the optimal preservation of the strain and its derivatives for long-term storage. The highest survival rates were achieved with cells that had reached the stationary phase and which had been subjected to freeze-drying in the presence of disaccharides (trehalose, maltose, and lactose) as lyoprotectants. Using fluorescence polarization techniques, we show that cell membranes of KT2440 were more rigid in the stationary phase than in the exponential phase of growth. This is consistent with the fact that cells grown in the stationary phase exhibited a higher proportion of C17:cyclopropane as a fatty acid than cells in the exponential phase. Mutants for the cfaB gene, which encodes the main C17:cyclopropane synthase, and for the cfaA gene, which encodes a minor C17:cyclopropane synthase, were constructed. These mutants were more sensitive to freeze-drying than wild-type cells, particularly the mutant with a knockout in the cfaB gene that produced less than 2% of the amount of C17:cyclopropane produced by the parental strain.

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Kochan, Kamila, Huadong Peng, Eunice S. H. Gwee, Ekaterina Izgorodina, Victoria Haritos, and Bayden R. Wood. "Raman spectroscopy as a tool for tracking cyclopropane fatty acids in genetically engineeredSaccharomyces cerevisiae." Analyst 144, no. 3 (2019): 901–12. http://dx.doi.org/10.1039/c8an01477a.

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Villorbina, Gemma, Lidia Roura, Francisco Camps, Jesús Joglar та Gemma Fabriàs. "Enzymatic Desaturation of Fatty Acids: Δ11Desaturase Activity on Cyclopropane Acid Probes". Journal of Organic Chemistry 68, № 7 (квітень 2003): 2820–29. http://dx.doi.org/10.1021/jo0267100.

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22

Lolli, Veronica, Margherita Dall’Asta, Augusta Caligiani, Daniele Del Rio, Miguel Angel de la Fuente, and Pilar Gómez-Cortés. "Detection of cyclopropane fatty acids in human breastmilk by GC-MS." Journal of Food Composition and Analysis 107 (April 2022): 104379. http://dx.doi.org/10.1016/j.jfca.2021.104379.

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23

Buist, Peter H., and Judy M. Findlay. "The biosynthesis of cyclopropane fatty acids. III. pH Dependence of methyl hydrogen exchange: gas chromatographic – mass spectral studies." Canadian Journal of Chemistry 63, no. 4 (April 1, 1985): 971–74. http://dx.doi.org/10.1139/v85-161.

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L-Methionine-methyl-d3 was administered to Lactobacillusplantarum and the deuterium content of the biosynthetic lactobacillic acid examined by gc–ms. By conducting the biosynthetic experiments in media of varying pH, it was shown that the production of d1-cyclopropane fatty acid increases with decreasing pH. Factors such as culture age and total activity of cyclopropane synthetase do not directly influence the extent of exchange.

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24

Lolli, Veronica, Margherita Dall’Asta, Daniele Del Rio, and Augusta Caligiani. "Identification of Cyclopropane Fatty Acids in Human Plasma after Controlled Dietary Intake of Specific Foods." Nutrients 12, no. 11 (October 30, 2020): 3347. http://dx.doi.org/10.3390/nu12113347.

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Cyclopropane fatty acids (CPFAs) are an investigated class of secondary fatty acids of microbial origin recently identified in foods. Even though the dietary daily intake of this class of compounds it has been recently estimated as not negligible, to date, no studies specifically have investigated their presence in human plasma after consumption of CPFA-rich sources. Therefore, the aims of this study were (i) to test CPFAs concentration in human plasma, thus demonstrating their in vivo bioaccessibility and potential bioavailability, (ii) to investigate a dose-response relationship between medium term chronic intake of CPFAs-rich foods and both CPFAs and plasma total fatty acid profiles in healthy subjects. Ten healthy normal weight adults were enrolled for conducting an in vivo study. Participants were asked to follow a CPFA-controlled diet for 3 weeks, consuming 50 g of Grana Padano cheese (GP) and 250 mL of whole cow milk, which correspond to a total of 22.1 mg of CPFAs. Fasting CPFAs concentration were monitored for eight timepoints during the whole study and plasma total fatty acids composition was determined by GC-MS. CPFAs, mainly dihydrosterculic acid (DHSA), were identified in plasma total fatty acids profile at the beginning of the study and after dietary treatment. A significant (p < 0.05) increase of CPFAs mean plasma concentration (n = 10) were observed at the end of the dietary intervention. Contrarily, the total fatty acids composition of the general plasma fatty acids profile did not significantly change (p ≥ 0.05) during the dietary intervention period. This is the first investigation demonstrating that CPFAs are bioaccessible in vivo and, as expected, their plasmatic concentration may be affected by consumption of CPFAs-rich foods. This research will open the door to further detailed research, which may better elucidate the role of these compounds in human health.

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25

Inuki, Shinsuke, and Yukari Fujimoto. "Total synthesis of naturally occurring chiral cyclopropane fatty acids and related compounds." Tetrahedron Letters 60, no. 16 (April 2019): 1083–90. http://dx.doi.org/10.1016/j.tetlet.2019.03.043.

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26

Amiri Moghaddam, Jamshid, Antonio Dávila-Céspedes, Stefan Kehraus, Max Crüsemann, Meryem Köse, Christa Müller, and Gabriele König. "Cyclopropane-Containing Fatty Acids from the Marine Bacterium Labrenzia sp. 011 with Antimicrobial and GPR84 Activity." Marine Drugs 16, no. 10 (October 8, 2018): 369. http://dx.doi.org/10.3390/md16100369.

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Bacteria of the family Rhodobacteraceae are widespread in marine environments and known to colonize surfaces, such as those of e.g., oysters and shells. The marine bacterium Labrenzia sp. 011 is here investigated and it was found to produce two cyclopropane-containing medium-chain fatty acids (1, 2), which inhibit the growth of a range of bacteria and fungi, most effectively that of a causative agent of Roseovarius oyster disease (ROD), Pseudoroseovarius crassostreae DSM 16950. Additionally, compound 2 acts as a potent partial, β-arrestin-biased agonist at the medium-chain fatty acid-activated orphan G-protein coupled receptor GPR84, which is highly expressed on immune cells. The genome of Labrenzia sp. 011 was sequenced and bioinformatically compared with those of other Labrenzia spp. This analysis revealed several cyclopropane fatty acid synthases (CFAS) conserved in all Labrenzia strains analyzed and a putative gene cluster encoding for two distinct CFASs is proposed as the biosynthetic origin of 1 and 2.

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To, Thi Mai Huong, Cosette Grandvalet, and Raphaëlle Tourdot-Maréchal. "Cyclopropanation of Membrane Unsaturated Fatty Acids Is Not Essential to the Acid Stress Response of Lactococcus lactis subsp. cremoris." Applied and Environmental Microbiology 77, no. 10 (March 18, 2011): 3327–34. http://dx.doi.org/10.1128/aem.02518-10.

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ABSTRACTCyclopropane fatty acids (CFAs) are synthetizedin situby the transfer of a methylene group fromS-adenosyl-l-methionine to a double bond of unsaturated fatty acid chains of membrane phospholipids. This conversion, catalyzed by the Cfa synthase enzyme, occurs in many bacteria and is recognized to play a key role in the adaptation of bacteria in response to a drastic perturbation of the environment. The role of CFAs in the acid tolerance response was investigated in the lactic acid bacteriumLactococcus lactisMG1363. A mutant of thecfagene was constructed by allelic exchange. Thecfagene encoding the Cfa synthase was cloned and introduced into the mutant to obtain the complemented strain for homologous system studies. Data obtained by gas chromatography (GC) and GC-mass spectrometry (GC-MS) validated that the mutant could not produce CFA. The CFA levels in both the wild-type and complemented strains increased upon their entry to stationary phase, especially with acid-adapted cells or, more surprisingly, with ethanol-adapted cells. The results obtained by performing quantitative reverse transcription-PCR (qRT-PCR) experiments showed that transcription of thecfagene was highly induced by acidity (by 10-fold with cells grown at pH 5.0) and by ethanol (by 9-fold with cells grown with 6% ethanol) in comparison with that in stationary phase. Cell viability experiments were performed after an acidic shock on the mutant strain, the wild-type strain, and the complemented strain, as a control. The higher viability level of the acid-adapted cells of the three strains after 3 h of shock proved that the cyclopropanation of unsaturated fatty acids is not essential forL. lactissubsp.cremorissurvival under acidic conditions. Moreover, fluorescence anisotropy data showed that CFA itself could not maintain the membrane fluidity level, particularly with ethanol-grown cells.

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Ordóñez, J. A., L. de la Hoz, J. I. Azcona, and B. Sanz. "Effect of growth temperature on lipid composition of Streptococcus faecium." Canadian Journal of Microbiology 31, no. 4 (April 1, 1985): 361–66. http://dx.doi.org/10.1139/m85-069.

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The effect of growth temperature on the lipid and fatty acid composition of Streptococcus faecium has been studied. No differences in the qualitative composition of S. faecium lipids were observed. In all isolated fractions (neutral lipids, glycolipids, and phospholipids plus other polar lipids), the major fatty acids were palmitic (C-16:0), palmitoleic (C-16:1), octadecenoic (C-18:1), and cyclopropane (C-19:0). Changes in the fatty acid composition of the different fractions were observed which depended on growth temperature; the most significant one was the decrease of octadecenoic acid and the increase of palmitic acid in glycolipids and polar lipids as the temperature increased. The level of cyclopropane C-19:0 was approximately eightfold lower at 8 °C than at the other temperatures tested (20, 30, and 45 °C).

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29

Grogan, D. W., and J. E. Cronan. "Characterization of Escherichia coli mutants completely defective in synthesis of cyclopropane fatty acids." Journal of Bacteriology 166, no. 3 (1986): 872–77. http://dx.doi.org/10.1128/jb.166.3.872-877.1986.

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30

Pasha, Mohammed Khysar, and Fasih Ahmad. "Analysis of triacylglycerols containing cyclopropane fatty acids in Sterculia fostida (Linn.) seed lipids." Journal of Agricultural and Food Chemistry 40, no. 4 (April 1992): 626–29. http://dx.doi.org/10.1021/jf00016a020.

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31

Carballeira, Néstor M., Nashbly Montano, Jan Vicente, and Abimael D. Rodriguez. "Novel Cyclopropane Fatty Acids from the Phospholipids of the Caribbean Sponge Pseudospongosorites suberitoides." Lipids 42, no. 6 (March 14, 2007): 519–24. http://dx.doi.org/10.1007/s11745-007-3047-3.

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32

Santalova, Elena A., and Vladimir A. Denisenko. "Fatty Acids from a Glass Sponge Aulosaccus sp. Occurrence of New Cyclopropane-Containing and Methyl-Branched Acids." Lipids 52, no. 1 (November 18, 2016): 73–82. http://dx.doi.org/10.1007/s11745-016-4214-1.

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33

Bao, X., S. Katz, M. Pollard, and J. Ohlrogge. "Carbocyclic fatty acids in plants: Biochemical and molecular genetic characterization of cyclopropane fatty acid synthesis of Sterculia foetida." Proceedings of the National Academy of Sciences 99, no. 10 (May 7, 2002): 7172–77. http://dx.doi.org/10.1073/pnas.092152999.

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34

Bernal, Claudio A., Jordi Rovira, Maryé E. Colandré, Roser Cussó, and Joan A. Cadefau. "Effects of dietary cis and trans unsaturated and saturated fatty acids on the glucose metabolites and enzymes of rats." British Journal of Nutrition 95, no. 5 (May 2006): 947–54. http://dx.doi.org/10.1079/bjn20061756.

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The aim of the present study was to examine whether the level of dietary cis fatty acid (c FA), or the isomers (trans or cis) and/or the saturation of the fatty acids at high dietary fat levels altered the intracellular glucose metabolites and certain regulatory enzyme activities in the skeletal muscle and liver of rats. The animals were fed for 30 d on either a recommended control diet (7% c FA, w/w) or a high-fat diet (20% fatty acids, w/w). The high-fat diet was enriched with either c FA, trans fatty acid (t FA), a moderate proportion of saturated fatty acid (MSFA), or a high proportion of saturated fatty acid (HSFA). The most striking findings were observed in the gastrocnemius muscle with a HSFA diet. There was a significant increase in glucose-6-phosphate (306 %), glucose-1-phosphate (245 %), fructose-6-phosphate (400 %), fructose-1,6-bisphosphate (86 %), glyceraldehyde- 3-phosphate (38 %), pyruvate (341 %), lactate (325 %), citrate (79 %) and the bisphosphorylated sugars as compared with the cFA diet. These changes were paralleled by an increase in muscle triacylglycerol content (49 %) and a decrease in glucose (39 %). In addition, the amount of cFA and the other types of fatty acid (i.e. t FA and MSFA) led to no great differences in glucose metabolism as compared with the respective control group. These data support the hypothesis that glucose changes induced by a HSFA diet are a multifaceted abnormality. Glucose and lactate transport and intracellular glucose metabolism could be the key biochemical defects involved in this detrimental effect on glucose metabolism.

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Petersen, SÃ¯Â¿Â½ren O., Peter Roslev, and Roland Bol. "Dynamics of a Pasture Soil Microbial Community after Deposition of Cattle Urine Amended with [13C]Urea." Applied and Environmental Microbiology 70, no. 11 (November 2004): 6363–69. http://dx.doi.org/10.1128/aem.70.11.6363-6369.2004.

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ABSTRACT Within grazed pastures, urine patches are hot spots of nitrogen turnover, since dietary N surpluses are excreted mainly as urea in the urine. This short-term experiment investigated 13C uptake in microbial lipids after simulated deposition of cattle urine at 10.0 and 17.1 g of urea C m−2. Confined field plots without or with cattle urine amendment were sampled after 4 and 14 days, and soil from 0- to 5-cm and 10- to 20-cm depths was analyzed for content and composition of phospholipid fatty acids (PLFAs) and for the distribution of urea-derived 13C among individual PLFAs. Carbon dioxide emissions were quantified, and the contributions derived from urea were assessed. Initial changes in PLFA composition were greater at the lower level of urea, as revealed by a principal-component analysis. At the higher urea level, osmotic stress was indicated by the dynamics of cyclopropane fatty acids and branched-chain fatty acids. Incorporation of 13C from [13C]urea was low but significant, and the largest amounts of urea-derived C were found in common fatty acids (i.e., 16:0, 16:1ω7c, and 18:1ω7) that would be consistent with growth of typical NH4 +-oxidizing (Nitrosomonas) and NO2 −-oxidizing (Nitrobacter) bacteria. Surprisingly, a 20‰ depletion of 13C in the cyclopropane fatty acid cy17:0 was observed after 4 days, which was replaced by a 10 to 20‰ depletion of that in cy19:0 after 14 days. Possible reasons for this pattern are discussed. Autotrophic nitrifiers could not be implicated in urea hydrolysis to any large extent, but PLFA dynamics and the incorporation of urea-derived 13C in PLFAs indicated a response of nitrifiers which differed between the two urea concentrations.

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Caligiani, Augusta, Angela Marseglia, and Gerardo Palla. "An Overview on the Presence of Cyclopropane Fatty Acids in Milk and Dairy Products." Journal of Agricultural and Food Chemistry 62, no. 31 (July 24, 2014): 7828–32. http://dx.doi.org/10.1021/jf4057204.

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Jansson, Lena, Joshua Tobias, Michael Lebens, Ann-Mari Svennerholm, and Susann Teneberg. "The Major Subunit, CfaB, of Colonization Factor Antigen I from Enterotoxigenic Escherichia coli Is a Glycosphingolipid Binding Protein." Infection and Immunity 74, no. 6 (June 2006): 3488–97. http://dx.doi.org/10.1128/iai.02006-05.

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ABSTRACT Bacterial adherence to mucosal surfaces is an important virulence trait of pathogenic bacteria. Adhesion of enterotoxigenic Escherichia coli (ETEC) to the intestine is mediated by a number of antigenically distinct colonization factors (CFs). One of the most common CFs is CFA/I. This has a fimbrial structure composed of a major repeating subunit, CfaB, and a single tip subunit, CfaE. The potential carbohydrate recognition by CFA/I was investigated by binding CFA/I-fimbriated bacteria and purified CFA/I fimbriae to a large number of variant glycosphingolipids separated on thin-layer chromatograms. For both fimbriated bacteria and purified fimbriae, specific interactions could be identified with a number of nonacid glycosphingolipids. These included glucosylceramide, lactosylceramide with phytosphingosine and/or hydroxy fatty acids, neolactotetraosylceramide, gangliotriaosylceramide, gangliotetraosylceramide, the H5 type 2 pentaglycosylceramide, the Lea-5 glycosphingolipid, the Lex-5 glycosphingolipid, and the Ley-6 glycosphingolipid. These glycosphingolipids were also recognized by recombinant E. coli expressing CFA/I in the absence of tip protein CfaE, as well as by purified fimbriae from the same strain. This demonstrates that the glycosphingolipid-binding capacity of CFA/I resides in the major CfaB subunit.

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38

ZAVAGLIA, ANDREA GÓMEZ, EDGARDO A. DISALVO, and GRACIELA L. DE ANTONI. "Fatty acid composition and freeze–thaw resistance in lactobacilli." Journal of Dairy Research 67, no. 2 (May 2000): 241–47. http://dx.doi.org/10.1017/s0022029900004179.

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The fatty acid composition and freeze–thaw resistance of eight strains of thermophilic lactobacilli were studied. Seven of these contained the same polar and neutral lipids, the five major components making up 90% of the cellular fatty acid pool being 14[ratio ]0, 16[ratio ]0, 16[ratio ]1, 18[ratio ]1 and C19 cyclopropane (cyc19[ratio ]0). Strain comparison by means of cluster analysis based on the fatty acid ratios using the overlap coefficient revealed two well defined clusters. One was formed by three strains of species Lactobacillus delbrueckii subsp. lactis and Lb. delbrueckii subsp. delbrueckii, the other included five strains of the species Lb. delbrueckii subsp. bulgaricus, Lb. acidophilus and Lb. helveticus. Resistance of strains with a high content of unsaturated fatty acids (66–70%) decreased with increasing cyc19[ratio ]0 concentrations. In contrast, in strains with a low concentration of unsaturated fatty acids (42–49%), increasing cyc19[ratio ]0 levels were associated with increased freeze–thaw resistance.

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Montanari, Chiara, Sylvain L. Sado Kamdem, Diana I. Serrazanetti, François-Xavier Etoa, and M. Elisabetta Guerzoni. "Synthesis of cyclopropane fatty acids in Lactobacillus helveticus and Lactobacillus sanfranciscensis and their cellular fatty acids changes following short term acid and cold stresses." Food Microbiology 27, no. 4 (June 2010): 493–502. http://dx.doi.org/10.1016/j.fm.2009.12.003.

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40

Řezanka, Tomáš, and Valery M. Dembitsky. "Identification of unusual cyclopropane monounsaturated fatty acids from the deep-water lake invertebrate Acanthogammarus grewingkii." Comparative Biochemistry and Physiology Part B: Comparative Biochemistry 109, no. 2-3 (October 1994): 407–13. http://dx.doi.org/10.1016/0305-0491(94)90023-x.

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41

Vega, Marta I., María del R. Cuenca, Emilio Rodríguez, and Danley Callieri. "Identification of Heptadecanoic and C19 Cyclopropane Fatty Acids in the Lipid Fraction of Zymomonas mobilis." Current Microbiology 41, no. 4 (October 1, 2000): 305–6. http://dx.doi.org/10.1007/s002840010139.

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42

Dionisi, Fabiola, Pierre-Alain Golay, Marina Elli, and Lauren B. Fay. "Stability of cyclopropane and conjugated linoleic acids during fatty acid quantification in lactic acid bacteria." Lipids 34, no. 10 (October 1999): 1107–15. http://dx.doi.org/10.1007/s11745-999-0462-8.

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Coloe, P. J., J. F. Slattery, P. Cavanaugh, and J. Vaughan. "The cellular fatty acid composition ofCampylobacterspecies isolated from cases of enteritis in man and animals." Journal of Hygiene 96, no. 2 (April 1986): 225–29. http://dx.doi.org/10.1017/s0022172400065992.

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SUMMARYThe cellular fatty acid composition of 41 strains of suspectedCampylobacter jejuni, 23 from human cases of gastroenteritis and 18 from animals, was examined by gas-liquid chromatography. Three of the 23 human isolates and 2 of 18 animal isolates did not contain 19:0 cyclopropane fatty acid and were identified asC. laridis. The remaining 36 strains had cellular fatty acid profiles consistent withC. jejunibut could be divided into three groups on the ratio of the concentration of 18:1 and 19:0 eycloproprane. Most human isolates (85%) were in groups II or III whereas most animal isolates (56%) were in group I. It is proposed that gas-liquid chromatographic analysis of cellular fatty acids is a relatively easy method for epidemiological typing ofC. jejuniisolates.

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Ozbek, A., and O. Aktas. "Identification of Three Strains of Mycobacterium Species Isolated from Clinical Samples Using Fatty Acid Methyl Ester Profiling." Journal of International Medical Research 31, no. 2 (April 2003): 133–40. http://dx.doi.org/10.1177/147323000303100210.

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The cellular fatty acid profiles of 67 strains belonging to three different species of the genus Mycobacterium were determined by gas chromatography of the fatty acid methyl esters, using the MIDI Sherlock® Microbial Identification System (MIS). The species M. tuberculosis, M. xenopi and M. avium complex were clearly distinguishable and could be identified based on the presence and concentrations of 12 fatty acids: 14:0, 15:0, 16:1ω7c, 16:1ω6c, 16:0, 17:0, 18:2ω6,9c, 18:1ω9c, 18:0, 10Me-18:0 tuberculostearic acid, alcohol and cyclopropane. Fatty acid analysis showed that there is great homogeneity within and heterogeneity between Mycobacterium species. Thus the MIS is an accurate, efficient and relatively rapid method for the identification of mycobacteria.

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Choi, Tae-Rim, Hun-Suk Song, Yeong-Hoon Han, Ye-Lim Park, Jun Young Park, Su-Yeon Yang, Shashi Kant Bhatia, et al. "Enhanced tolerance to inhibitors of Escherichia coli by heterologous expression of cyclopropane-fatty acid-acyl-phospholipid synthase (cfa) from Halomonas socia." Bioprocess and Biosystems Engineering 43, no. 5 (January 27, 2020): 909–18. http://dx.doi.org/10.1007/s00449-020-02287-8.

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Lakkoju, Babi, and Vandana Vemulapalli. "Preparation and properties of bio-lubricants of neopentylglycol esters from various acids." Research Journal of Chemistry and Environment 26, no. 1 (December 25, 2021): 9–18. http://dx.doi.org/10.25303/2601rjce0918.

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In this work, two different neopentyl glycol (NPG) esters have been synthesized from NPG with 10- undecylenic acid (UDA) and calophyllum fatty acid (CFA) by the esterification process by using para toluene sulfonic acid as a catalyst. The esterification reaction progress has been determined by collecting measured water by using the Dean Stack apparatus. The prepared ester structures have been characterized by NMR, IR and the general physico-chemical behaviors such as density, viscosity, flash point, pour point and copper strip corrosion were determined. Moreover, these prepared ester properties have been compared to commercial ISO VG grade lubes.

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Tunlid, Anders, Bruce H. Baird, Melanie B. Trexler, Stefan Olsson, Robert H. Findlay, Goran Odham та David C. White. "Determination of phospholipid ester-linked fatty acids and poly β-hydroxybutyrate for the estimation of bacterial biomass and activity in the rhizosphere of the rape plant Brassica napus (L.)". Canadian Journal of Microbiology 31, № 12 (1 грудня 1985): 1113–19. http://dx.doi.org/10.1139/m85-210.

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Examination of seven strains of gram-negative bacteria isolated from the rhizosphere of the rape plant showed profiles of fatty acids, ester-linked to their phospholipids that were distinctly different from sterile roots. The bacteria were enriched in short and branched saturated, cyclopropane and monoenoic fatty acids in which the unsaturation was formed by the anerobic desaturase pathway when growth was on a medium simulating root exudates. This suite of fatty acids was significantly increased in sand and in roots of rape plants grown from seeds in sands inoculated with these organisms at the start of the experiments. Some of the bacteria formed the endogenous storage polymer poly β-hydroxybutyrate in monocultures. Poly β-hydroxybutyrate was formed by the bacteria in the inoculated sand in large amounts but not by the bacteria that were recovered from the roots. This suggests that bacteria associated with the roots were in balanced growth, whereas the bacteria in the sand were lacking essential nutrients and showed an unbalanced growth response. These chemical analyses provided estimates of the bacterial biomass (from the sum of bacterial ester-linked phospholipid fatty acids) and the metabolic status (poly β-hydroxybutyrate to phospholipid fatty acid ratio) in this experiment. With further definition of lipid biomarkers of soil microorganisms these experimental techniques may be extended to the rhizosphere.

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48

Lolli, Veronica, Margherita Dall’Asta, Daniele Del Rio, Gerardo Palla, and Augusta Caligiani. "Presence of cyclopropane fatty acids in foods and estimation of dietary intake in the Italian population." International Journal of Food Sciences and Nutrition 70, no. 4 (November 19, 2018): 467–73. http://dx.doi.org/10.1080/09637486.2018.1540556.

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49

Chen, Yuan Yao, and Michael G. Gänzle. "Influence of cyclopropane fatty acids on heat, high pressure, acid and oxidative resistance in Escherichia coli." International Journal of Food Microbiology 222 (April 2016): 16–22. http://dx.doi.org/10.1016/j.ijfoodmicro.2016.01.017.

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50

Lolli, Veronica, Erica Renes, Augusta Caligiani, Miguel Angel de la Fuente, and Pilar Gómez-Cortés. "Cyclopropane Fatty Acids as Quality Biomarkers of Cheeses from Ewes Fed Hay- and Silage-Based Diets." Journal of Agricultural and Food Chemistry 69, no. 33 (August 13, 2021): 9654–60. http://dx.doi.org/10.1021/acs.jafc.1c03312.

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