• Title/Summary/Keyword: chemical acids

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Undecanoic Acid, Lauric Acid, and N-Tridecanoic Acid Inhibit Escherichia coli Persistence and Biofilm Formation

  • Jin, Xing;Zhou, Jiacheng;Richey, Gabriella;Wang, Mengya;Choi Hong, Sung Min;Hong, Seok Hoon
    • Journal of Microbiology and Biotechnology
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    • v.31 no.1
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    • pp.130-136
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    • 2021
  • Persister cell formation and biofilms of pathogens are extensively involved in the development of chronic infectious diseases. Eradicating persister cells is challenging, owing to their tolerance to conventional antibiotics, which cannot kill cells in a metabolically dormant state. A high frequency of persisters in biofilms makes inactivating biofilm cells more difficult, because the biofilm matrix inhibits antibiotic penetration. Fatty acids may be promising candidates as antipersister or antibiofilm agents, because some fatty acids exhibit antimicrobial effects. We previously reported that fatty acid ethyl esters effectively inhibit Escherichia coli persister formation by regulating an antitoxin. In this study, we screened a fatty acid library consisting of 65 different fatty acid molecules for altered persister formation. We found that undecanoic acid, lauric acid, and N-tridecanoic acid inhibited E. coli BW25113 persister cell formation by 25-, 58-, and 44-fold, respectively. Similarly, these fatty acids repressed persisters of enterohemorrhagic E. coli EDL933. These fatty acids were all medium-chain saturated forms. Furthermore, the fatty acids repressed Enterohemorrhagic E. coli (EHEC) biofilm formation (for example, by 8-fold for lauric acid) without having antimicrobial activity. This study demonstrates that medium-chain saturated fatty acids can serve as antipersister and antibiofilm agents that may be applied to treat bacterial infections.

Chemical composition of different parts of ramie (Boehmeria nivea)

  • Cho, Sunghun;Lee, Jaemin;Kim, Young Mi;Jung, Yong-Su;Kim, Ho Bang;Cho, Eun Ju;Lee, Sanghyun
    • Korean Journal of Agricultural Science
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    • v.44 no.1
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    • pp.95-103
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    • 2017
  • Ramie (Boehmeria nivea) is a perennial herbaceous plant belonging to the family Urticaceae. It was used in folk remedies for diuretic or anti-pyretic purposes and as an hepatoprotective, anti-oxidant, and anti-inflammation agent. In this study, we investigated the composition of free sugars, amino acids, fatty acids, organic acids, and total polyphenol contents in parts of ramie (root, stem, and leaf) and different harvest areas (10 areas). Overall, free sugars were found as sucrose, glucose, fructose, and galactose at concentrations ranging from 24.5 to 1173.8 mg/g. Amino acids lysine, threonine, tyrosine, phenylalanine, and histidine were detected at concentrations of 33.8 to 3735.3 mg/g. Major fatty acids were linoleic acid, palmitic acid, and linolenic acid at concentrations of 7.3 to 364.4 mg/g. In organic acids, the concentration of malic acid was highest of all with 672.2 mg/g. The content of free sugars, amino acids, fatty acids, organic acids, and total polyphenol was higher in leaves than in roots and stems. In contrast, the total polyphenol content was higher in roots with 33.7 - 219.4 mg/g than in leaves or in stems. As seen in collecting region, the contents of free sugars, amino acids, fatty acids, organic acids, and total polyphenol of Bn-33, 39, 55, 65, and 90 were higher than other samples. Chemical compositions of different parts of ramie are important factors to consider in manufacturing functional foods. The results of this study provide fundamental information on the chemical compositions of ramie parts and would help develop new functional foods from ramie leaves or the whole plant.

Analysis of Minerals, Amino Acids,and Vitamin of Lespedeza cuneata (비수리의 미네랄, 이미노산, 비타민 분석)

  • Ding, Ji-Lu;Lim, Ik-Jae;Lee, Hee-Duck;Cha, Wol-Suk
    • KSBB Journal
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    • v.21 no.6 s.101
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    • pp.414-417
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    • 2006
  • For developing functional biomaterials, chemical analysis of Lespedeza cuneata including minerals, amino acids and vitamin were investigated. Minerals of L. cuneata were found to be calcium, potassium, magnesium, phosphorus, sodium, iron, manganese, zinc and copper. Among the free amino acid, proline was 33.77 mg% that were 67.2% of free amino acids and essential amino acids were 7.49 mg%. Total amino acids were analyzed as 2,817 mg% and the content of glutamic acid (496.00 mg%) was highest. In case of vitamin, the highest components was vitamin E with 33.03 mg%.

Rate-acceleration of TEMPO-mediated Polymerization of Styrene in the Presence of Various Acids

  • Hong, Chang-Kook;Jang, Heang-Sin;Hong, Sang-Hyun;Shim, Sang-Eun
    • Macromolecular Research
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    • v.17 no.1
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    • pp.14-18
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    • 2009
  • The acceleration effect of various organic acids, such as methanesulfonic acid (MSA), ethanesulfonic acid (ESA), 4,4'-sulfonyldibenzoic acid (SDA), diphenylacetic acid (DPAA), and $\rho$-toluenesulfonic acid (TSA), on the rate of styrene bulk polymerization with 2,2,6,6-tetramethylpiperidinyloxy (TEMPO) and benzoyl peroxide (BPO) was investigated. The addition of organic acids significantly accelerated the rate. Among these organic acids, DPAA showed an efficient rate-accelerating effect with living nature of polymerization. When DPAA was used as a rate-accelerating additive for TEMPO-mediated living free radical polymerization (LFRP), the rate of polymerization was dramatically enhanced, the linearity of reaction kinetics was successfully maintained, and the polydispersity was effectively controlled.

On the Hydroxydation of Saturated Fatty Acids (1) (飽和脂肪酸의 酸素添加反應에 關한 硏究 (第1報))

  • Bahk, Jong-Hwan;Han, Kap-Hyon
    • Journal of the Korean Chemical Society
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    • v.5 no.1
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    • pp.18-21
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    • 1961
  • The hydroxydation of the saturated fatty acids in order to prepare hydroxy fatty acids in the presence of catalysts was reported by several workers. The considering commercial applications of this reaction, authors studied on the hydroxydation of natural fats composed of nonhydroxy saturated fatty acids. Tallow and stearic acid were tested with manganese dioxide as catalyst, $110 {\pm}3^{\circ}C,$ and under atmospheric oxygen. The highest hydroxyl values were obtained at 20 hours for tallow, 107.6 and at 14 hours for stearic add, 116.0.

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High-Performance Soft Carbons Prepared by Treatment with Various Phosphorus Acids

  • Jeong, Seong Hun;Koh, Jeong Yoon;Kim, Tae Jeong;Jung, Yongju
    • Bulletin of the Korean Chemical Society
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    • v.35 no.8
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    • pp.2357-2360
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    • 2014
  • Phosphorus-doped soft carbons were successfully prepared by carbonizing petroleum cokes treated with phosphorus acids, such as $H_3PO_2$, $H_3PO_3$, and $H_3PO_4$. The effect of the type of phosphorus acids used on the composition, structure, and electrochemical performance of the soft carbons was extensively investigated. The soft carbons modified with $H_3PO_3$ and $H_3PO_4$ exhibited dramatically improved reversible capacities and outstanding rate capabilities.

Prediction of Explosion Limits of Organic Acids Using Combustion Chemical Stoichiometric Coefficients and Heats of Combustion (연소열 및 화학양론계수를 이용한 유기산류의 폭발한계의 예측)

  • Ha, Dong-Myeong
    • Fire Science and Engineering
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    • v.27 no.3
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    • pp.47-51
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    • 2013
  • The explosion limit is one of the major combustion properties used to determine the fire and explosion hazards of the flammable substances. The explosion limit of organic acids have been shown to be correlated the heat of combustion and the chemical stoichiometric coefficients. In this study, the lower explosion and upper explosion limits of organic acids were predicted by using the heat of combustion and chemical stoichiometric coefficients. The values calculated by the proposed equations agreed with literature data within a few percent. From the given results, using the proposed methodology, it is possible to predict the explosion limits of the other organic acids.