Solvation thermodynamics of L-cystine, L-tyrosine, and L-leucine in aqueous-electrolyte media

Science.gov (United States)

Roy, Sanjay; Guin, Partha Sarathi; Mahali, Kalachand; Dolui, Bijoy Krishna

2017-12-01

Solubilities of L-cystine, L-tyrosine, and L-leucine in aqueous NaCl media at 298.15 K have been studied. Indispensable and related solvent parameters such as molar mass, molar volume, etc., were also determined. The results are used to evaluate the standard transfer Gibbs free energy, cavity forming enthalpy of transfer, cavity forming transfer Gibbs free energy and dipole-dipole interaction effects during the course of solvation. Various weak interactions involving solute-solvent or solvent-solvent molecules were characterized in order to find their role on the solvation of these amino acids.

Preclinical and clinical evaluation of O-[11C]methyl-L-tyrosine for tumor imaging by positron emission tomography

International Nuclear Information System (INIS)

Ishiwata, Kiichi; Tsukada, Hideo; Kubota, Kazuo; Nariai, Tadashi; Harada, Norihiro; Kawamura, Kazunori; Kimura, Yuichi; Oda, Keiichi; Iwata, Ren; Ishii, Kenji

2005-01-01

We performed preclinical and clinical studies of O-[ 11 C]methyl-L-tyrosine, a potential tracer for imaging amino acid transport of tumors by positron emission tomography (PET). Examinations of the radiation-absorbed dose by O-[ 11 C]methyl-L-tyrosine and the acute toxicity and mutagenicity of O-methyl-L-tyrosine showed suitability of the tracer for clinical use. The whole-body imaging of monkeys and healthy humans by PET showed low uptake of O-[ 11 C]methyl-L-tyrosine in all normal organs except for the urinary track and bladder, suggesting that the O-[ 11 C]methyl-L-tyrosine PET has the potential for tumor imaging in the whole-body. Finally, the brain tumor imaging was preliminarily demonstrated

Photoinduced electron transfer for an eosin-tyrosine conjugate. Activity of the tyrosinate anion in long-range electron transfer in a protein-like polymer matrix

Energy Technology Data Exchange (ETDEWEB)

Jones, G. II; Feng, Z.; Oh, C. [Boston Univ., MA (United States)

1995-03-23

The Xanthene dye eosin Y has been modified via a thiohydantoin link to the amine terminus of the amino acid L-tyrosine. Photochemical electron transfer involving the singlet state of the dye and the attached phenol-containing residue led to a reduction in eosin fluorescence quantum yield and lifetime for aqueous solutions at elevated pH. The conjugate provided an electron transfer product of relatively long lifetime (1 {mu}s range) observed by flash photolysis of solutions at pH 12.0, conditions under which the tyrosine moiety is ionized. The effects of binding of the conjugate in the polymer poly(vinylpyrrolidone) (PVP) on the rates of electron transfer of species of different charge type were examined. 30 refs., 5 figs., 1 tab.

Synthesis of specifically labelled L-phenylalanines using phenylalanine ammonia lyase activity

International Nuclear Information System (INIS)

Haedener, A.; Tamm, Ch.

1987-01-01

Specifically labelled L-phenylalanines have been prepared using a variety of classical synthetic methods in combination with phenylalanine ammonia lyase (PAL) enzyme activity of the yeast Rhodosporidium toruloides ATCC 10788 or Rhodotorula glutinis IFO 0559, respectively. Thus, L-[2- 2 H]phenyl-[2- 2 H]alanine was formed from (E) -[2,2'- 2 H 2 ]cinnamic acid and ammonia in 46% yield, whereas L-phenyl-[2- 13 C, 15 N]alanine was obtained from (E)-[2- 13 C]cinnamic acid in 45% overall yield. Generally, labelled cinnamic acids were recovered in pure form from the reaction mixture, with a loss of 6-8%. Likewise, unchanged 15 NH 3 was reisolated as 15 NH 4 Cl after steam distillation with overall losses of less than 4%. Labelled cinnamic acids were prepared by Knoevenagel condensations between appropriately labelled benzaldehydes and malonic acids. [2- 2 H]Benzaldehyde was obtained from 2-bromotoluene by decomposition of the corresponding Grignard reagent with 2 H 2 O and subsequent oxidation. Since simple molecules, most of them commercially available in labelled form or otherwise easily accessible, may serve as starting material, and due to its defined stereochemistry, the reaction catalysed by PAL opens a short and attractive route to specifically labelled L-phenylalanines. (author)

Purification, characterization and gene cloning of thermostable O-acetyl-L-serine sulfhydrylase forming β-cyano-L-alanine

International Nuclear Information System (INIS)

Omura, Hironori; Yoshida, Toyokazu; Nagasawa, Toru; Kobayashi, Michihiko; Shimizu, Sakayu

2003-01-01

A thermophilic and cyanide ion-tolerant bacterium, Bacillus stearothermophilus CN3 isolated from a hot spring in Japan, was found to produce thermostable β-cyano-L-alanine synthase. The enzyme catalyzes the synthesis of β-cyano-L-alanine from O-acetyl-L-serine and cyanide ions. The purified enzyme has a molecular mass of approximately 70 kDa and consists of two identical sub-units. It was stable in the pH range of 6.0 to 10.0 and up to 70degC. The enzyme also catalyzes the synthesis of various β-substituted-L-alanine derivatives from O-acetyl-L-serine and nucleophilic reagents. The gene encoding the β-cyano-L-alanine synthase was isolated from B. stearothermophilus CN3. Sequence homology analysis revealed that the β-cyano-L-alanine synthase of the bacterium is O-acetyl-L-serine sulfhydrylase. A recombinant plasmid, constructed by ligation of the cloned gene and an expression vector, pKK223-3, was introduced into E. coli JM109. The transformed E. coli cells overexpressed β-cyano-L-alanine synthase. Heat stable β-cyano-L-alanine synthase can be applied to the synthesis of [4- 11 C]L-2,4-diaminobutyric acid as a tracer for positron emission tomography. (author)

Purification, characterization and gene cloning of thermostable O-acetyl-L-serine sulfhydrylase forming {beta}-cyano-L-alanine

Energy Technology Data Exchange (ETDEWEB)

Omura, Hironori; Yoshida, Toyokazu; Nagasawa, Toru [Gifu Univ. (Japan). Dept. of Biomolecular Science; Kuroda, Masako [Ikeda Food Research Co., Ltd., Fukuyama, Hiroshima (Japan); Kobayashi, Michihiko; Shimizu, Sakayu [Kyoto Univ. (Japan). Agricultural Sciences

2003-10-01

A thermophilic and cyanide ion-tolerant bacterium, Bacillus stearothermophilus CN3 isolated from a hot spring in Japan, was found to produce thermostable {beta}-cyano-L-alanine synthase. The enzyme catalyzes the synthesis of {beta}-cyano-L-alanine from O-acetyl-L-serine and cyanide ions. The purified enzyme has a molecular mass of approximately 70 kDa and consists of two identical sub-units. It was stable in the pH range of 6.0 to 10.0 and up to 70degC. The enzyme also catalyzes the synthesis of various {beta}-substituted-L-alanine derivatives from O-acetyl-L-serine and nucleophilic reagents. The gene encoding the {beta}-cyano-L-alanine synthase was isolated from B. stearothermophilus CN3. Sequence homology analysis revealed that the {beta}-cyano-L-alanine synthase of the bacterium is O-acetyl-L-serine sulfhydrylase. A recombinant plasmid, constructed by ligation of the cloned gene and an expression vector, pKK223-3, was introduced into E. coli JM109. The transformed E. coli cells overexpressed {beta}-cyano-L-alanine synthase. Heat stable {beta}-cyano-L-alanine synthase can be applied to the synthesis of [4-{sup 11}C]L-2,4-diaminobutyric acid as a tracer for positron emission tomography. (author)

Activities of methionine-γ-lyase in the acidophilic archaeon “Ferroplasma acidarmanus” strain fer1

Directory of Open Access Journals (Sweden)

Khan MA

2013-04-01

Full Text Available M A Khan,1 Madeline M López-Muñoz,2 Charles W Kaspar,3 Kai F Hung1 1Department of Biological Sciences, Eastern Illinois University, Charleston, IL, USA; 2Department of Biology, Universidad de Puerto Rico, Mayaguez, Puerto Rico; 3Bacteriology Department, University of Wisconsin, Madison, WI, USA Abstract: Biogeochemical processes on exposed pyrite ores result in extremely high levels of sulfuric acid at these locations. Acidophiles that thrive in these conditions must overcome significant challenges, including an environment with proton concentrations at pH 3 or below. The role of sulfur metabolism in the archaeon “Ferroplasma acidarmanus” strain fer1's ability to thrive in this environment was investigated due to its growth-dependent production of methanethiol, a volatile organic sulfur compound. Two putative sequences for methionine-γ-lyase (EC 4.4.1.11, an enzyme known to carry out α, γ-elimination on L-methionine to produce methanethiol, were identified in fer1. Bioinformatic analyses identified a conserved pyridoxal-5'-phosphate (PLP binding domain and a partially conserved catalytic domain in both putative sequences. Detection of PLP-dependent and L-methionine-dependent production of α-keto compounds and thiol groups in fer1 confirmed the presence of methionine-γ-lyase activity. Further, fer1 lysate was capable of processing related substrates, including D-methionine, L-cysteine, L-cystathionine, and L/D-homocysteine. When the two putative fer1 methionine-γ-lyase gene-coded proteins were expressed in Escherichia coli cells, one sequence demonstrated an ability to carry out α, γ-elimination activity, while the other exhibited γ-replacement activity. These fer1 methionine-γ-lyases also exhibited optimum pH, substrate specificity, and catalytic preferences that are different from methionine-γ-lyases from other organisms. These differences are discussed in the context of molecular phylogeny constructed using a maximum

1H NMR studies of substrate hydrogen exchange reactions catalyzed by L-methionine gamma-lyase

International Nuclear Information System (INIS)

Esaki, N.; Nakayama, T.; Sawada, S.; Tanaka, H.; Soda, K.

1985-01-01

Hydrogen exchange reactions of various L-amino acids catalyzed by L-methionine gamma-lyase (EC 4.4.1.11) have been studied. The enzyme catalyzes the rapid exchange of the alpha- and beta-hydrogens of L-methionine and S-methyl-L-cysteine with deuterium from the solvent. The rate of alpha-hydrogen exchange was about 40 times faster than that of the enzymatic elimination reaction of the sulfur-containing amino acids. The enzyme also catalyzes the exchange reaction of alpha- and beta-hydrogens of the straight-chain L-amino acids which are not susceptible to elimination. The exchange rates of the alpha-hydrogen and the total beta-hydrogens of L-alanine and L-alpha-aminobutyrate with deuterium followed first-order kinetics. For L-norvaline, L-norleucine, S-methyl-L-cysteine, and L-methionine, the rate of alpha-hydrogen exchange followed first-order kinetics, but the rate of total beta-hydrogen exchange decreased due to a primary isotope effect at the alpha-position. L-Phenylalanine and L-tryptophan slowly underwent alpha-hydrogen exchange. The pro-R hydrogen of glycine was deuterated stereospecifically

Chemoenzymatic Synthesis of Oligo(L-cysteine) for Use as a Thermostable Bio-Based Material.

Science.gov (United States)

Ma, Yinan; Sato, Ryota; Li, Zhibo; Numata, Keiji

2016-01-01

Oligomerization of thiol-unprotected L-cysteine ethyl ester (Cys-OEt) catalyzed by proteinase K in aqueous solution has been used to synthesize oligo(L-cysteine) (OligoCys) with a well-defined chemical structure and relatively large degree of polymerization (DP) up to 16-17 (average 8.8). By using a high concentration of Cys-OEt, 78.0% free thiol content was achieved. The thermal properties of OligoCys are stable, with no glass transition until 200 °C, and the decomposition temperature could be increased by oxidation. Chemoenzymatically synthesized OligoCys has great potential for use as a thermostable bio-based material with resistance to oxidation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preclinical and clinical evaluation of O-[{sup 11}C]methyl-L-tyrosine for tumor imaging by positron emission tomography

Energy Technology Data Exchange (ETDEWEB)

Ishiwata, Kiichi [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo 173-0022 (Japan)]. E-mail: ishiwata@pet.tmig.or.jp; Tsukada, Hideo [Central Research Laboratory, Hamamatsu Photonics K.K., Hamakita 434-8601 (Japan); Kubota, Kazuo [Department of Radiology, Division of Nuclear Medicine, International Medical Center of Japan, Shinjuku-ku, Tokyo 162-8655 (Japan); Nariai, Tadashi [Department of Neurosurgery, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8519 (Japan); Harada, Norihiro [Department of Radiology, Division of Nuclear Medicine, International Medical Center of Japan, Shinjuku-ku, Tokyo 162-8655 (Japan); Kawamura, Kazunori [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo 173-0022 (Japan); SHI Accelerator Service Ltd., Shinagawa-ku, Tokyo 141-8686 (Japan); Kimura, Yuichi [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo 173-0022 (Japan); Oda, Keiichi [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo 173-0022 (Japan); Iwata, Ren [CYRIC, Tohoku University, Aoba-ku, Sendai 980-8578 (Japan); Ishii, Kenji [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo 173-0022 (Japan)

2005-04-01

We performed preclinical and clinical studies of O-[{sup 11}C]methyl-L-tyrosine, a potential tracer for imaging amino acid transport of tumors by positron emission tomography (PET). Examinations of the radiation-absorbed dose by O-[{sup 11}C]methyl-L-tyrosine and the acute toxicity and mutagenicity of O-methyl-L-tyrosine showed suitability of the tracer for clinical use. The whole-body imaging of monkeys and healthy humans by PET showed low uptake of O-[{sup 11}C]methyl-L-tyrosine in all normal organs except for the urinary track and bladder, suggesting that the O-[{sup 11}C]methyl-L-tyrosine PET has the potential for tumor imaging in the whole-body. Finally, the brain tumor imaging was preliminarily demonstrated.

Aspergillus niger PA2: a novel strain for extracellular biotransformation of L-tyrosine into L-DOPA.

Science.gov (United States)

Agarwal, Pragati; Pareek, Nidhi; Dubey, Swati; Singh, Jyoti; Singh, R P

2016-05-01

L-DOPA (3,4-dihydroxyphenyl-L-alanine), an amino acid derivative is the most widely used drug of choice for the treatment of Parkinson's disease and other neurologic injuries. The present study deals with the elevated biochemical transformation of L-tyrosine to L-DOPA by Aspergillus niger PA2, a potent tyrosinase producer, isolated from decomposed food wastes. This appears to be the first report on A. niger as a notable extracellular tyrosinase producer. The extracellular tyrosinase activity produced remarkably higher levels of L-DOPA, i.e. 2.44 mg mL(-1) when the media was supplemented with 5 mg mL(-1) L-tyrosine. The optimum pH for tyrosinase production was 6.0, with the maximal L-DOPA production at the same pH. The product thus produced was analyzed by thin-layer chromatography, UV spectroscopy, high-performance liquid chromatography and Fourier transform infrared spectroscopy, that had denoted this to be L-DOPA. Kinetic parameters viz. Y p/s, Q s and Q p had further indicated the notable levels of production. Thus, Aspergillus niger PA2 could be a promising resource and may be further exploited for large-scale production of L-DOPA.

Biofortification (Se: Does it increase the content of phenolic compounds in virgin olive oil (VOO?

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Roberto D'Amato

Full Text Available Extra-Virgin Olive Oil (EVOO is a fundamental component of the Mediterranean diet and it may contain several anti-oxidant substances, such as phenols. Previous research has shown that this food may be enriched in phenols by spraying a sodium-selenate solution (100 mg L-1 Se onto the crop canopy before flowering. The aim of this research was to evaluate the effect of this Se-fertilization before flowering (cv. Leccino on the phenolic profile of EVOOs, and test to what extent such effects depend on the weather pattern, as observed in two contrasting experimental seasons (2013 and 2014. Results showed that Se-fertilisation enriched EVOOs both in selenium (up to 120 μg kg-1 and in phenols (up to 401 mg kg-1. This latter enrichment was related to an increase in PAL (L-Phenylalanine Ammonia-Lyase activities and it was largely independent on the climatic pattern. Considering the phenolic profile, oleacein, ligustroside, aglycone and oleocanthal were the most affected compounds and were increased by 57, 50 and 32%, respectively. All these compounds, especially oleacein, have been shown to exert a relevant anti-oxidant activity, contributing both to the shelf-life of EVOOs and to positive effects on human health. It is suggested that Se-fertilisation of olive trees before flowering may be an interesting practice, particularly with poor cultivars and cold and rainy weather patterns, which would normally lead to the production of EVOOs with unfavourable phenolic profile.

Biofortification (Se): Does it increase the content of phenolic compounds in virgin olive oil (VOO)?

Science.gov (United States)

D’Amato, Roberto; Proietti, Primo; Onofri, Andrea; Regni, Luca; Esposto, Sonia; Servili, Maurizio; Businelli, Daniela; Selvaggini, Roberto

2017-01-01

Extra-Virgin Olive Oil (EVOO) is a fundamental component of the Mediterranean diet and it may contain several anti-oxidant substances, such as phenols. Previous research has shown that this food may be enriched in phenols by spraying a sodium-selenate solution (100 mg L-1 Se) onto the crop canopy before flowering. The aim of this research was to evaluate the effect of this Se-fertilization before flowering (cv. Leccino) on the phenolic profile of EVOOs, and test to what extent such effects depend on the weather pattern, as observed in two contrasting experimental seasons (2013 and 2014). Results showed that Se-fertilisation enriched EVOOs both in selenium (up to 120 μg kg-1) and in phenols (up to 401 mg kg-1). This latter enrichment was related to an increase in PAL (L-Phenylalanine Ammonia-Lyase) activities and it was largely independent on the climatic pattern. Considering the phenolic profile, oleacein, ligustroside, aglycone and oleocanthal were the most affected compounds and were increased by 57, 50 and 32%, respectively. All these compounds, especially oleacein, have been shown to exert a relevant anti-oxidant activity, contributing both to the shelf-life of EVOOs and to positive effects on human health. It is suggested that Se-fertilisation of olive trees before flowering may be an interesting practice, particularly with poor cultivars and cold and rainy weather patterns, which would normally lead to the production of EVOOs with unfavourable phenolic profile. PMID:28448631

UV-Vis spectroscopy of tyrosine side-groups in studies of protein structure. Part 1: basic principles and properties of tyrosine chromophore.

Science.gov (United States)

Antosiewicz, Jan M; Shugar, David

2016-06-01

Spectroscopic properties of tyrosine residues may be employed in structural studies of proteins. Here we discuss several different types of UV-Vis spectroscopy, like normal, difference and second-derivative UV absorption spectroscopy, fluorescence spectroscopy, linear and circular dichroism spectroscopy, and Raman spectroscopy, and corresponding optical properties of the tyrosine chromophore, phenol, which are used to study protein structure.

Synthesis of specifically labelled L-phenylalanines using phenylalanine ammonia lyase activity

Energy Technology Data Exchange (ETDEWEB)

Haedener, A.; Tamm, Ch.

1987-11-01

Specifically labelled L-phenylalanines have been prepared using a variety of classical synthetic methods in combination with phenylalanine ammonia lyase (PAL) enzyme activity of the yeast Rhodosporidium toruloides ATCC 10788 or Rhodotorula glutinis IFO 0559, respectively. Thus, L-(2-/sup 2/H)phenyl-(2-/sup 2/H)alanine was formed from (E) -(2,2'-/sup 2/H/sub 2/)cinnamic acid and ammonia in 46% yield, whereas L-phenyl-(2-/sup 13/C, /sup 15/N)alanine was obtained from (E)-(2-/sup 13/C)cinnamic acid in 45% overall yield. Generally, labelled cinnamic acids were recovered in pure form from the reaction mixture, with a loss of 6-8%. Likewise, unchanged /sup 15/NH/sub 3/ was reisolated as /sup 15/NH/sub 4/Cl after steam distillation with overall losses of less than 4%. Labelled cinnamic acids were prepared by Knoevenagel condensations between appropriately labelled benzaldehydes and malonic acids. (2-/sup 2/H)Benzaldehyde was obtained from 2-bromotoluene by decomposition of the corresponding Grignard reagent with /sup 2/H/sub 2/O and subsequent oxidation. Since simple molecules, most of them commercially available in labelled form or otherwise easily accessible, may serve as starting material, and due to its defined stereochemistry, the reaction catalysed by PAL opens a short and attractive route to specifically labelled L-phenylalanines.

The conversion of phenylalanine to tyrosine in man. Direct measurement by continuous intravenous tracer infusions of L-[ring-2H5]phenylalanine and L-[1-13C] tyrosine in the postabsorptive state

International Nuclear Information System (INIS)

Clarke, J.T.; Bier, D.M.

1982-01-01

Steady state phenylalanine and tyrosine turnover and the rate of conversion of phenylalanine of tyrosine in vivo were determined in 6 healthy postabsorptive adult volunteers. Continuous infusions of tracer amounts of L-[ring- 2 H5]phenylalanine were determined intravenously for 13-14 hr. After 9-10 hr, a priming dose followed by a continuous infusion of L-[1- 13 C]tyrosine was added and maintained, along with the [ 2 H5]phenylalanine infusion, for 4 hr. Venous plasma samples were obtained before the initiation of each infusion and every 30 min during the course of the combined [ 2 H5]phenylalanine and [ 13 C]tyrosine infusion for determination of isotopic enrichments of [ 2 H5]phenylalanine, [ 13 C]tyrosine, and [ 2 H4]tyrosine by gas chromatograph-mass spectrometric analysis of the N-trifluoroacetyl-, methyl ester derivatives of the amino acids. Calculated from the observed enrichments, free phenylalanine and tyrosine turnover rates were 36.1 +/- 5.1 mumole . kg-1 . h-1 and 39.8 +/- 3.5 mumole . kg-1 . h-1, respectively. Phenylalanine was converted to tyrosine at the rate of 5.83 +/- 0.59 mumole . kg-1 . h-1, accounting for approximately 16% of either the phenylalanine or the tyrosine flux. The results indicate that the normal basal steady state phenylalanine hydroxylase activity in vivo in man is lower than that obtained from phenylalanine loading studies. This supports the existence of some type of substance activation of the enzyme as reflected in the previously reported exponential relationship between phenylalanine concentration and phenylalanine hydroxylase activity in vitro. The use of continuous simultaneous infusions of tracer amounts of stable isotope-labeled phenylalanine and tyrosine provides a direct means for studying physiological regulation of phenylalanine hydroxylase activity in vivo

Tracer experiment administering L-phenylalanine-U-14C and L-tyrosine-U-14C to the tissue slices of bamboo shoots

International Nuclear Information System (INIS)

Kozukue, E.; Mizuno, S.

1987-01-01

Uniformly 14 C-labeled L-phenylalanine and L-tyrosine were administered to tissue slices of both top and base sections of bamboo shoots. Alcohol soluble substances were extracted and then separated into organic acid, sugar and amino acid fractions by ion exchange chromatography. The homogentisic acid fraction among the organic acids was collected by high-performance liquid chromatography (HPLC) and its radioactivity was measured, while the alcohol insoluble residue was used for the analysis of lignin aldehyde by the method of alkaline nitrobenzene oxidation. 1. The two labeled amino acids were steadily incorporated into the tissues during incubation and rapidly converted to organic acid, sugar and alcohol insoluble residue, especially the latter. 2. On determining the amount of phenylalanine converted to tyrosine, it was found that this was extremely small. 3. The incorporation of phenylalanine-U- 14 C into alcohol insoluble residue was higher than that of tyrosine in both sections. 4. Although the conversion into lignin aldehyde from phenylalanine-U- 14 C was higher than that from tyrosine-U- 14 C, it was found that tyrosine incorporated into the shoots was converted to a remarkable extent for formation of lignin aldehyde. 5. The incorporation of phenylalanine and tyrosine into homogentisic acid was very low. From these results, we assume that the conversion of phenylalanine to tyrosine or of tyrosine to homogentisic acid is very small, and that a part of the high amount of tyrosine in the shoots may be used for formation of lignin

Characterization of C-S lyase from Lactobacillus delbrueckii subsp. bulgaricus ATCC BAA-365 and its potential role in food flavour applications.

Science.gov (United States)

Allegrini, Alessandra; Astegno, Alessandra; La Verde, Valentina; Dominici, Paola

2017-04-01

Volatile thiols have substantial impact on the aroma of many beverages and foods. Thus, the control of their formation, which has been linked to C-S lyase enzymatic activities, is of great significance in industrial applications involving food flavours. Herein, we have carried out a spectroscopic and functional characterization of a putative pyridoxal 5'-phosphate (PLP)-dependent C-S lyase from the lactic acid bacterium Lactobacillus delbrueckii subsp. bulgaricus ATCC BAA-365 (LDB C-S lyase). Recombinant LDB C-S lyase exists as a tetramer in solution and shows spectral properties of enzymes containing PLP as cofactor. The enzyme has a broad substrate specificity toward sulphur-containing amino acids with aminoethyl-L-cysteine and L-cystine being the most effective substrates over L-cysteine and L-cystathionine. Notably, the protein also reveals cysteine-S-conjugate β-lyase activity in vitro, and is able to cleave a cysteinylated substrate precursor into the corresponding flavour-contributing thiol, with a catalytic efficiency higher than L-cystathionine. Contrary to similar enzymes of other lactic acid bacteria however, LDB C-S lyase is not capable of α,γ-elimination activity towards L-methionine to produce methanethiol, which is a significant compound in flavour development. Based on our results, future developments can be expected regarding the flavour-forming potential of Lactobacillus C-S lyase and its use in enhancing food flavours. © The Authors 2017. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.

Light-induced Variation in Phenolic Compounds in Cabernet Sauvignon Grapes (Vitis vinifera L. Involves Extensive Transcriptome Reprogramming of Biosynthetic Enzymes, Transcription Factors, and Phytohormonal Regulators

Directory of Open Access Journals (Sweden)

Jun Wang

2017-04-01

Full Text Available Light environments have long been known to influence grape (Vitis vinifera L. berry development and biosynthesis of phenolic compounds, and ultimately affect wine quality. Here, the accumulation and compositional changes of hydroxycinnamic acids (HCAs and flavonoids, as well as global gene expression were analyzed in Cabernet Sauvignon grape berries under sunlight exposure treatments at different phenological stages. Sunlight exposure did not consistently affect the accumulation of berry skin flavan-3-ol or anthocyanin among different seasons due to climatic variations, but increased HCA content significantly at véraison and harvest, and enhanced flavonol accumulation dramatically with its timing and severity degree trend. As in sunlight exposed berries, a highly significant correlation was observed between the expression of genes coding phenylalanine ammonia-lyase, 4-coumarate: CoA ligase, flavanone 3-hydroxylase and flavonol synthase family members and corresponding metabolite accumulation in the phenolic biosynthesis pathway, which may positively or negatively be regulated by MYB, bHLH, WRKY, AP2/EREBP, C2C2, NAC, and C2H2 transcription factors (TFs. Furthermore, some candidate genes required for auxin, ethylene and abscisic acid signal transductions were also identified which are probably involved in berry development and flavonoid biosynthesis in response to enhanced sunlight irradiation. Taken together, this study provides a valuable overview of the light-induced phenolic metabolism and transcriptome changes, especially the dynamic responses of TFs and signaling components of phytohormones, and contributes to the further understanding of sunlight-responsive phenolic biosynthesis regulation in grape berries.

Light-induced Variation in Phenolic Compounds in Cabernet Sauvignon Grapes (Vitis vinifera L.) Involves Extensive Transcriptome Reprogramming of Biosynthetic Enzymes, Transcription Factors, and Phytohormonal Regulators.

Science.gov (United States)

Sun, Run-Ze; Cheng, Guo; Li, Qiang; He, Yan-Nan; Wang, Yu; Lan, Yi-Bin; Li, Si-Yu; Zhu, Yan-Rong; Song, Wen-Feng; Zhang, Xue; Cui, Xiao-Di; Chen, Wu; Wang, Jun

2017-01-01

Light environments have long been known to influence grape ( Vitis vinifera L.) berry development and biosynthesis of phenolic compounds, and ultimately affect wine quality. Here, the accumulation and compositional changes of hydroxycinnamic acids (HCAs) and flavonoids, as well as global gene expression were analyzed in Cabernet Sauvignon grape berries under sunlight exposure treatments at different phenological stages. Sunlight exposure did not consistently affect the accumulation of berry skin flavan-3-ol or anthocyanin among different seasons due to climatic variations, but increased HCA content significantly at véraison and harvest, and enhanced flavonol accumulation dramatically with its timing and severity degree trend. As in sunlight exposed berries, a highly significant correlation was observed between the expression of genes coding phenylalanine ammonia-lyase, 4-coumarate: CoA ligase, flavanone 3-hydroxylase and flavonol synthase family members and corresponding metabolite accumulation in the phenolic biosynthesis pathway, which may positively or negatively be regulated by MYB, bHLH, WRKY, AP2/EREBP, C2C2, NAC, and C2H2 transcription factors (TFs). Furthermore, some candidate genes required for auxin, ethylene and abscisic acid signal transductions were also identified which are probably involved in berry development and flavonoid biosynthesis in response to enhanced sunlight irradiation. Taken together, this study provides a valuable overview of the light-induced phenolic metabolism and transcriptome changes, especially the dynamic responses of TFs and signaling components of phytohormones, and contributes to the further understanding of sunlight-responsive phenolic biosynthesis regulation in grape berries.

Light-induced Variation in Phenolic Compounds in Cabernet Sauvignon Grapes (Vitis vinifera L.) Involves Extensive Transcriptome Reprogramming of Biosynthetic Enzymes, Transcription Factors, and Phytohormonal Regulators

Science.gov (United States)

Sun, Run-Ze; Cheng, Guo; Li, Qiang; He, Yan-Nan; Wang, Yu; Lan, Yi-Bin; Li, Si-Yu; Zhu, Yan-Rong; Song, Wen-Feng; Zhang, Xue; Cui, Xiao-Di; Chen, Wu; Wang, Jun

2017-01-01

Light environments have long been known to influence grape (Vitis vinifera L.) berry development and biosynthesis of phenolic compounds, and ultimately affect wine quality. Here, the accumulation and compositional changes of hydroxycinnamic acids (HCAs) and flavonoids, as well as global gene expression were analyzed in Cabernet Sauvignon grape berries under sunlight exposure treatments at different phenological stages. Sunlight exposure did not consistently affect the accumulation of berry skin flavan-3-ol or anthocyanin among different seasons due to climatic variations, but increased HCA content significantly at véraison and harvest, and enhanced flavonol accumulation dramatically with its timing and severity degree trend. As in sunlight exposed berries, a highly significant correlation was observed between the expression of genes coding phenylalanine ammonia-lyase, 4-coumarate: CoA ligase, flavanone 3-hydroxylase and flavonol synthase family members and corresponding metabolite accumulation in the phenolic biosynthesis pathway, which may positively or negatively be regulated by MYB, bHLH, WRKY, AP2/EREBP, C2C2, NAC, and C2H2 transcription factors (TFs). Furthermore, some candidate genes required for auxin, ethylene and abscisic acid signal transductions were also identified which are probably involved in berry development and flavonoid biosynthesis in response to enhanced sunlight irradiation. Taken together, this study provides a valuable overview of the light-induced phenolic metabolism and transcriptome changes, especially the dynamic responses of TFs and signaling components of phytohormones, and contributes to the further understanding of sunlight-responsive phenolic biosynthesis regulation in grape berries. PMID:28469625

Thermostating highly confined fluids.

Science.gov (United States)

Bernardi, Stefano; Todd, B D; Searles, Debra J

2010-06-28

In this work we show how different use of thermostating devices and modeling of walls influence the mechanical and dynamical properties of confined nanofluids. We consider a two dimensional fluid undergoing Couette flow using nonequilibrium molecular dynamics simulations. Because the system is highly inhomogeneous, the density shows strong fluctuations across the channel. We compare the dynamics produced by applying a thermostating device directly to the fluid with that obtained when the wall is thermostated, considering also the effects of using rigid walls. This comparison involves an analysis of the chaoticity of the fluid and evaluation of mechanical properties across the channel. We look at two thermostating devices with either rigid or vibrating atomic walls and compare them with a system only thermostated by conduction through vibrating atomic walls. Sensitive changes are observed in the xy component of the pressure tensor, streaming velocity, and density across the pore and the Lyapunov localization of the fluid. We also find that the fluid slip can be significantly reduced by rigid walls. Our results suggest caution in interpreting the results of systems in which fluid atoms are thermostated and/or wall atoms are constrained to be rigid, such as, for example, water inside carbon nanotubes.

Evaluation of PAL activity, Phenolic and Flavonoid Contents in Three Pistachio (Pistacia vera L. Cultivars Grafted onto Three Different Rootstocks

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N. Nadernejad

2013-08-01

Full Text Available Phenylalanine ammonia lyase (PAL is a biochemical marker of the environmental stress and plays a pivotal role in phenolic synthesis. The lower ROS level and oxidative damage was observed in grafted plants and the rootstocks have a profound influence on the biochemical composition, especially phenolic compounds. Regarding the importance of the effect rootstocks have on scion in pistachio trees, this study was carried out to assess and compare three pistachio cultivars ("Ahmadaghaii", "Ohadi" and "Kallehghuchi" on three rootstocks (Mutica, Ahli, Sarakhs. PAL activity, phenolic compounds, flavonoid and anthocyanin contents in leaves, flowers and fruits were measured toward the selection of the most suitable and compatible rootstock/scion resistant to environmental stresses. The results showed that PAL activity was different among the cultivars and organs. A positive correlation was observed between PAL activity and phenolic compounds in the leaves and flowers of Mutica- Ahmadaghaii, suggesting that it is more resistant than the others to environmental stresses. PAL activity and total phenolics in fruits of pistachio suffered a decrease when the maturation processes began. The hulls of the pistachio fruits contained high levels of phenolic compounds especially in Mutica-Ahmadaghaii suggesting its function as a protective layer and a defense chemical against ultraviolet radiation and pathogen. Our results indicated the presence of a number of bioactive compounds in kernels with the highest amount belonging to Mutica- Ahmadaghaii, and therefore it is concluded that pistachio rootstocks may affect the antioxidant compounds in kernels.

Properties of the humic-like material arising from the photo-transformation of L-tyrosine

Energy Technology Data Exchange (ETDEWEB)

Berto, Silvia, E-mail: silvia.berto@unito.it [Università di Torino, Dipartimento Chimica, via P. Giuria, 7, 10125 Torino (Italy); De Laurentiis, Elisa; Tota, Tiziana; Chiavazza, Enrico; Daniele, Pier Giuseppe; Minella, Marco [Università di Torino, Dipartimento Chimica, via P. Giuria, 7, 10125 Torino (Italy); Isaia, Marco [Università di Torino, Dipartimento di Scienze della Vita e Biologia dei Sistemi, Via Accademia Albertina 13, Torino 10123 (Italy); Brigante, Marcello [Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand (France); CNRS, UMR 6296, ICCF, BP 80026, F-63177 Aubière (France); Vione, Davide, E-mail: davide.vione@unito.it [Università di Torino, Dipartimento Chimica, via P. Giuria, 7, 10125 Torino (Italy)

2016-03-01

The UVB photolysis of L-tyrosine yields species with fluorescence and absorption spectra that are very similar to those of humic substances. By potentiometric measurements, chemical modeling and the application of NMR, mass spectrometry and laser flash photolysis, it was possible to get insights into the structural and chemical properties of the compounds derived by the L-tyrosine phototransformation. The photolytic process follows aromatic-ring hydroxylation and dimerization. The latter is presumably linked with the photoinduced generation of tyrosyl (phenoxy-type) radicals, which have a marked tendency to dimerize and possibly oligomerize. Interestingly, photoinduced transformation gives compounds with protogenic and complexation capabilities similar to those of the humic substances that occur naturally in surface waters. This finding substantiates a new and potentially important abiotic (photolytic) pathway for the formation of humic compounds in surface-water environments. - Highlights: • Tyrosine photolysis proceeds through deamination, hydroxylation and dimerization. • Dimerization could be linked to the photoinduced formation of tyrosyl radicals. • New protogenic sites are formed by irradiation, compared to the parent amino acid. • The irradiated material has higher copper complexation capacity than tyrosine. • Humic-like substances derived from tyrosine could complex Cu in surface waters.

Alfalfa contains substantial 9-hydroperoxide lyase activity and a 3Z:2E-enal isomerase

NARCIS (Netherlands)

Vliegenthart, J.F.G.; Noordermeer, M.A.; Veldink, G.A.

1999-01-01

Fatty acid hydroperoxides formed by lipoxygenase can be cleaved by hydroperoxide lyase resulting in the formation of short-chain aldehydes and omega-oxo acids. Plant hydroperoxide lyases use 13- or 9-hydroperoxy linoleic and linolenic acid as substrates. Alfalfa (Medicago sativa L.) has been

The phenolic acids of some species of the Oenothera L. genus

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Tadeusz Krzaczek

2014-01-01

Full Text Available The occurence and approximative quantitative proportions of the phenolic acids in four species of the Oenothera L. genus was determined by the method of TLC and HPLC. In all species of Oenothera L. genus the permanent occurrence of acids: 2-hydroxy-4-metoxybenzoic, salicylic, ferulic, syringic, vanillic, p-coumaric, p-hydroxybenzoic, p-hydroxyphenylacetic, γ-rezorcil, gentysic, protocatechuic, caffeic and gallic has been confirmed. Whereas the other phenolic acids: o-coumaric, o-hydroxyphenylacetic and pirocatechuic were found in some species of the Oenothera L. genus only.

Phenolics in Slovenian bilberries ( Vaccinium myrtillus L.) and blueberries ( Vaccinium corymbosum L.).

Science.gov (United States)

Moze, Spela; Polak, Tomaz; Gasperlin, Lea; Koron, Darinka; Vanzo, Andreja; Poklar Ulrih, Natasa; Abram, Veronika

2011-07-13

Phenolics from bilberries ( Vaccinium myrtillus L.) sampled from seven different locations and highbush blueberries ( Vaccinium corymbosum L.) from one location in Slovenia were analyzed. In samples of both species 15 anthocyanins were identified by LC-MS/MS. Their contents were expressed as cyanidin 3-glucoside equivalents (C3GE); bilberries contained 1210.3 ± 111.5 mg C3GE/100 g fw and blueberries 212.4 ± 14.1 mg C3GE/100 g fw. Glycosides of delphinidin and cyanidin were predominant (488.5 vs 363.6 mg C3GE/100 g fw) in the bilberries and glycosides of malvidin (108.0 vs 100.8 mg C3GE/100 g fw) in the blueberries, whereas the contents of peonidin were lowest (74.5 vs 4.8 mg C3GE/100 g fw) in both berries. The contents of flavanols, flavonols, phenolic acids, and stilbenes were determined by LC-MS. For the first time, rutin was identified (bilberries, 0.2 ± 0.0 mg/100 g fw; blueberries, 3.1 ± 0.1 mg/100 g fw). Chlorogenic acid (as 3-caffeoylquinic acid) was the most abundant among the phenolic acids (23.1 ± 1.0 mg/100 g fw in bilberries and 70.0 ± 3.4 mg/100 g fw in blueberries). Statistical analysis shows that the content of 27 individual flavonoids, phenolic acids, and stilbenes can be used to identify the picking region of these Slovenian bilberries.

RESPONSE OF PHENOLIC METABOLISM INDUCED BY ALUMINIUM TOXICITY IN FAGOPYRUM ESCULENTUM MOENCH. PLANTS.

Science.gov (United States)

Smirnov, O E; Kosyan, A M; Kosyk, O I; Taran, N Yu

2015-01-01

Buckwheat genus (Fagopyrum Mill.) is one of the aluminium tolerant taxonomic units of plants. The aim of the study was an evaluation of the aluminium (50 μM effect on phenolic accumulation in various parts of buckwheat plants (Fagopyrum esculentum Moench). Detection of increasing of total phenolic content, changes in flavonoid and anthocyanin content and phenylalanine ammonia-lyase activity (PAL) were revealed over a period of 10 days of exposure to aluminium. The most significant effects of aluminium treatment on phenolic compounds accumulation were total phenolic content increasing (by 27.2%) and PAL activity rising by 2.5 times observed in leaves tissues. Received data could be helpful to understand the aluminium tolerance principles and relationships of phenolic compounds to aluminium phytotoxicity.

Enzymatic syntheses of some 11C-labelled analogues of L-tyrosine and L-tryptophan

International Nuclear Information System (INIS)

Bjurling, P.; Malmborg, P.; Langstroem, B.

1990-01-01

In the elucidation of biochemical processes by use of positron emission tomography (PET), the multi-tracer approach can be valuable. In previous work, the authors have been studying the dopaminergic and serotonergic neurosystems by use of 11 C-labelled L-DOPA and 5-hydroxy-L-tryptophan, respectively. They have now developed the syntheses of several analogues of tyrosine and tryptophan, labelled with 11 C in the β-position, which are of interest for use in similar applications

Enzymatic conversion of D-galactose to D-tagatose: heterologous expression and characterisation of a thermostable L-arabinose isomerase from Thermoanaerobacter mathranii.

Science.gov (United States)

Jørgensen, F; Hansen, O C; Stougaard, P

2004-06-01

The ability to convert D-galactose into D-tagatose was compared among a number of bacterial L-arabinose isomerases ( araA). One of the most efficient enzymes, from the anaerobic thermophilic bacterium Thermoanaerobacter mathranii, was produced heterologously in Escherichia coli and characterised. Amino acid sequence comparisons indicated that this enzyme is only distantly related to the group of previously known araA sequences in which the sequence similarity is evident. The substrate specificity and the Michaelis-Menten constants of the enzyme determined with L-arabinose, D-galactose and D-fucose also indicated that this enzyme is an unusual, versatile L-arabinose isomerase which is able to isomerise structurally related sugars. The enzyme was immobilised and used for production of D-tagatose at 65 degrees C. Starting from a 30% solution of D-galactose, the yield of D-tagatose was 42% and no sugars other than D-tagatose and D-galactose were detected. Direct conversion of lactose to D-tagatose in a single reactor was demonstrated using a thermostable beta-galactosidase together with the thermostable L-arabinose isomerase. The two enzymes were also successfully combined with a commercially available glucose isomerase for conversion of lactose into a sweetening mixture comprising lactose, glucose, galactose, fructose and tagatose.

Phenolics in Primula veris L. and P. elatior (L. Hill Raw Materials

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Katarzyna Bączek

2017-01-01

Full Text Available Primula veris L. and Primula elatior (L. Hill represent medicinal plants used for the production of herbal teas and preparations with antioxidant and expectorant activity. Flowers and roots of both species possess the same biological activity. In the presented study, raw materials of wild growing P. veris and P. elatior were compared in terms of the content and composition of phenolic compounds using a fast and simple HPLC-DAD method. The study showed that flowers of both species were rich in flavonoids. However, P. veris flowers were characterized with a distinctly higher content of isorhamnetin-3-O-glucoside, astragalin, and (+-catechin, whereas P. elatior occurred to be a richer source of rutoside and isorhamnetin-3-O-rutinoside. Hyperoside was found exclusively in P. elatior flowers. Phenolic glycosides (primverin and primulaverin were identified only in the roots. Their content was about ten times higher in P. veris in comparison with P. elatior underground organs. The obtained results clearly show that both Primula species differ distinctly in terms of the content and composition of phenolic compounds. The compounds differentiating both species to the highest degree (hyperoside, in flowers, as well as primverin and primulaverin, in the roots may be useful chemical markers in the identification and evaluation of both species.

PHENOLIC COMPOUNDS OF WATER-ETHANOLIC EXTRACT OF MENTHA LONGIFOLIA L

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O. A. Grebennikova

2014-01-01

Full Text Available The article represents data about qualitative and quantitative composition of phenolic compounds in water-ethanol extract of perspective clone of Mentha longifolia L. of NBE-NSC selection. Phenolic substances content in water-ethanol extract amounted to 3003.3 mg/100g. 13 components were determined in the extract. The extract contains caffeic acid, chlorogenic acid isomers, rosmarinic acid and glycosides of luteolin. Rosmarinic acid (50.2% prevails among phenolic substances of Mentha longifolia extract. The conclusion is that the use of this extract is possible to create products with high biological value

Phenolic Composition and Evaluation of the Antimicrobial Activity of Free and Bound Phenolic Fractions from a Peruvian Purple Corn (Zea mays L.) Accession.

Science.gov (United States)

Gálvez Ranilla, Lena; Christopher, Ashish; Sarkar, Dipayan; Shetty, Kalidas; Chirinos, Rosana; Campos, David

2017-12-01

Beneficial effects on overall gut health by phenolic bioactives-rich foods are potentially due to their modulation of probiotic gut bacteria and antimicrobial activity against pathogenic bacteria. Based on this rationale, the effect of the free and bound phenolic fractions from a Peruvian purple corn accession AREQ-084 on probiotic lactic acid bacteria such as Lactobacillus helveticus and Bifidobacterium longum and the gastric cancer-related pathogen Helicobacter pylori was evaluated. The free and bound phenolic composition was also determined by ultra-performance liquid chromatography. Anthocyanins were the major phenolic compounds (310.04 mg cyanidin-3-glucoside equivalents/100 g dry weight, DW) in the free phenolic fraction along with hydroxycinnamic acids such as p-coumaric acid derivatives, followed by caffeic and ferulic acid derivatives. The bound phenolic form had only hydroxycinnamic acids such as ferulic acid, p-coumaric acid, and a ferulic acid derivative with ferulic acid being the major phenolic compound (156.30 mg/100 g DW). These phenolic compounds were compatible with beneficial probiotic lactic acid bacteria such as L. helveticus and B. longum as these bacteria were not inhibited by the free and bound phenolic fractions at 10 to 50 mg/mL and 10 mg/mL of sample doses, respectively. However, the pathogenic H. pylori was also not inhibited by both purple corn phenolic forms at same above sample doses. This study provides the preliminary base for the characterization of phenolic compounds of Peruvian purple corn biodiversity and its potential health benefits relevant to improving human gut health. This study provides insights that Peruvian purple corn accession AREQ-084 can be targeted as a potential source of health-relevant phenolic compounds such as anthocyanins along with hydroxycinnamic acids linked to its dietary fiber fraction. Additionally, these phenolic fractions did not affect the gut health associated beneficial bacteria nor the pathogenic

Facile, one-step controlled synthesis of Se nanocrystals in the presence of L-tyrosine

International Nuclear Information System (INIS)

Wang Xiufang; Zhang Weiqiang; Shen Yuhua; Xie Anjian; Huang Lachun

2011-01-01

Highlights: → Se was synthesized via a novel and facile pathway. → The morphologies and the crystalline phases of Se can be easily controlled. → Tyrosine is excellent reducing agent and soft template for the synthesis of Se. → It is possible to provide an excellent route to obtain nanomaterials. - Abstract: Se with different morphologies was synthesized using L-tyrosine as reducing agent and soft template by means of hydrothermal method. The method was simple and convenient to handle. The reaction process was monitored using ultraviolet-visible spectroscopy (UV-vis) and Fourier-transform infrared spectroscopy (FTIR). The morphology and crystalline phase were determined by transmission electron microscopy (TEM), scanning electronic microscopy (SEM) and X-ray diffraction (XRD) pattern. The results show that the morphologies and the crystalline phases of Se can be easily controlled. By varying the concentration ratio of L-tyrosine to selenious acid, the morphologies and crystalline phases of Se were not changed, but the diameter of Se was different. Se nano-rods are obtained in the lower temperature, and there is a transformation of microspheres into nanorods of Se with the increase of reaction time or reaction temperature. In addition, we discuss the possible mechanism of the reduction of SeO 3 2- ions by L-tyrosine. The eco-friendly, biogenic synthesis strategy could be widely used for preparing inorganic/organic biocomposites.

Crystallization and preliminary X-ray analysis of βC–S lyases from two oral streptococci

International Nuclear Information System (INIS)

Kezuka, Yuichiro; Yoshida, Yasuo; Nonaka, Takamasa

2009-01-01

The βC-S lyases from two oral bacteria, Streptococcus anginosus and S. gordonii, were cloned, overproduced, purified and crystallized. The obtained crystals were characterized by X-ray diffraction. Hydrogen sulfide, which causes oral malodour, is generally produced from l-cysteine by the action of βC–S lyase from oral bacteria. The βC–S lyases from two oral bacteria, Streptococcus anginosus and S. gordonii, have been cloned, overproduced, purified and crystallized. X-ray diffraction data were collected from the two types of crystals using synchrotron radiation. The crystal of S. anginosus βC–S lyase belonged to the orthorhombic space group P2 1 2 1 2 1 , with unit-cell parameters a = 67.0, b = 111.1, c = 216.4 Å, and the crystal of S. gordonii βC–S lyase belonged to the same space group, with unit-cell parameters a = 58.0, b = 73.9. c = 187.6 Å. The structures of the βC–S lyases were solved by molecular-replacement techniques

Investigating Hydrogen Bonding in Phenol Using Infrared Spectroscopy and Computational Chemistry

Science.gov (United States)

Fedor, Anna M.; Toda, Megan J.

2014-01-01

The hydrogen bonding of phenol can be used as an introductory model for biological systems because of its structural similarities to tyrosine, a para-substituted phenol that is an amino acid essential to the synthesis of proteins. Phenol is able to form hydrogen bonds readily in solution, which makes it a suitable model for biological…

RESEARCH OF PHENOLIC COMPLEX OF LEAVES OF MESPILUS GERMANICA L.

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N. N. Vdovenko-Martynova

2014-01-01

Full Text Available Leaves of Mespilus germanica L. from Rosaceae family gathered in Kabardino Balkaria regions and in Botanical garden of Pyatigorsk Medical and Pharmaceutical Institute. The purpose of the study is examination of phenolic compounds in the raw materieals under analysis. Qualitative composition and quantitative identification of phenolic compounds in the air-dry raw materials of samples under study was done using qualitative reactions and high performance liquid chromatography method (HPLC. 13 compounds were received, 8 of them were identified as the substances of phenolic origin: flavonoids (quercetine, taxofolin, luteolin, hydroxycoric acids (gallic, chlorogenic, ferulic, polyphenolic compounds (epigallocatechin gallate, epicatechin. The sum of identified phenolic compounds amounted to 78,24% of all compounds found by the given method.

Tracer experiment administering L-phenylalanine-U-{sup 14}C and L-tyrosine-U-{sup 14}C to the tissue slices of bamboo shoots

Energy Technology Data Exchange (ETDEWEB)

Kozukue, E. [Kenmei Women' s Junior Coll., Himeji, Hyogo (Japan); Mizuno, S.

1987-09-15

Uniformly {sup 14}C-labeled L-phenylalanine and L-tyrosine were administered to tissue slices of both top and base sections of bamboo shoots. Alcohol soluble substances were extracted and then separated into organic acid, sugar and amino acid fractions by ion exchange chromatography. The homogentisic acid fraction among the organic acids was collected by high-performance liquid chromatography (HPLC) and its radioactivity was measured, while the alcohol insoluble residue was used for the analysis of lignin aldehyde by the method of alkaline nitrobenzene oxidation. 1. The two labeled amino acids were steadily incorporated into the tissues during incubation and rapidly converted to organic acid, sugar and alcohol insoluble residue, especially the latter. 2. On determining the amount of phenylalanine converted to tyrosine, it was found that this was extremely small. 3. The incorporation of phenylalanine-U-{sup 14}C into alcohol insoluble residue was higher than that of tyrosine in both sections. 4. Although the conversion into lignin aldehyde from phenylalanine-U-{sup 14}C was higher than that from tyrosine-U-{sup 14}C, it was found that tyrosine incorporated into the shoots was converted to a remarkable extent for formation of lignin aldehyde. 5. The incorporation of phenylalanine and tyrosine into homogentisic acid was very low. From these results, we assume that the conversion of phenylalanine to tyrosine or of tyrosine to homogentisic acid is very small, and that a part of the high amount of tyrosine in the shoots may be used for formation of lignin.

Effects of a common worldwide drink (Beer) on L-Phenylalanine and L-Tyrosine fibrillar assemblies

Science.gov (United States)

Banik, Debasis; Banerjee, Pavel; Sabeehuddin, Ghazi; Sarkar, Nilmoni

2017-11-01

In this letter, small amount of beer [0.42-2.08% (v/v)] is employed to investigate the fibril inhibition kinetics of 1 mM L-Phenylalanine and L-Tyrosine (relevant to disease condition) using Fluorescence Lifetime imaging Microscopy (FLIM), Field Emission Scanning Electron Microscopy (FESEM) and High Resolution Transmission Electron Microscopic (HR-TEM) techniques. Our results indicate that 1.67 and 0.42% of beer is sufficient for effective breakdown of L-Phe and L-Tyr assemblies, respectively. Quantitative information about fibril inhibition is obtained from Fluorescence Correlation Spectroscopic (FCS) measurements. We have shown that the morphology of L-Phe changes to L-Tyr in presence of 2,2‧-Bipyridine-3,3‧-diol (BP(OH)2).

Identification and Partial Characterization of an L-Tyrosine Aminotransferase (TAT from Arabidopsis thaliana

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Pranav R. Prabhu

2010-01-01

Full Text Available The aminotransferase gene family in the model plant Arabidopsis thaliana consists of 44 genes. Twenty six of these enzymes are classified as characterized meaning that the reaction(s that the enzyme catalyzes are documented using experimental means. The remaining 18 enzymes are uncharacterized and are therefore deemed putative. Our laboratory is interested in elucidating the function(s of the remaining putative aminotransferase enzymes. To this end, we have identified and partially characterized an aminotransferase (TAT enzyme from Arabidopsis annotated by the locus tag At5g36160. The full-length cDNA was cloned and the purified recombinant enzyme was characterized using in vitro and in vivo experiments. In vitro analysis showed that the enzyme is capable of interconverting L-Tyrosine and 4-hydroxyphenylpyruvate, and L-Phenylalanine and phenylpyruvate. In vivo analysis by functional complementation showed that the gene was able to complement an E. coli with a background of aminotransferase mutations that confers auxotrophy for L-Tyrosine and L-Phenylalanine.

Quantitation of heparosan with heparin lyase III and spectrophotometry.

Science.gov (United States)

Huang, Haichan; Zhao, Yingying; Lv, Shencong; Zhong, Weihong; Zhang, Fuming; Linhardt, Robert J

2014-02-15

Heparosan is Escherichia coli K5 capsule polysaccharide, which is the key precursor for preparing bioengineered heparin. A rapid and effective quantitative method for detecting heparosan is important in the large-scale production of heparosan. Heparin lyase III (Hep III) effectively catalyzes the heparosan depolymerization, forming unsaturated disaccharides that are measurable using a spectrophotometer at 232 nm. We report a new method for the quantitative detection of heparosan with heparin lyase III and spectrophotometry that is safer and more specific than the traditional carbazole assay. In an optimized detection system, heparosan at a minimum concentration of 0.60 g/L in fermentation broth can be detected. Copyright © 2013 Elsevier Inc. All rights reserved.

Ultrasound treatment on phenolic metabolism and antioxidant capacity of fresh-cut pineapple during cold storage.

Science.gov (United States)

Yeoh, Wei Keat; Ali, Asgar

2017-02-01

Ultrasound treatment at different power output (0, 25 and 29W) and exposure time (10 and 15min) was used to investigate its effect on the phenolic metabolism enzymes, total phenolic content and antioxidant capacity of fresh-cut pineapple. Following ultrasound treatment at 25 and 29W, the activity of phenylalanine ammonia lyase (PAL) was increased significantly (Ppineapple was significantly (Ppineapple. Results suggest that hormetic dosage of ultrasound treatment can enhance the activity of PAL and total phenolic content and hence the total antioxidant capacity to encounter with oxidative stress. Copyright © 2016. Published by Elsevier Ltd.

Phenolic metabolites in carnivorous plants: Inter-specific comparison and physiological studies.

Science.gov (United States)

Kováčik, Jozef; Klejdus, Bořivoj; Repčáková, Klára

2012-03-01

Despite intensive phytochemical research, data related to the accumulation of phenols in carnivorous plants include mainly qualitative reports. We have quantified phenolic metabolites in three species: Drosera capensis, Dionaea muscipula and Nepenthes anamensis in the "leaf" (assimilatory part) and the "trap" (digestive part). For comparison, commercial green tea was analysed. Phenylalanine ammonia-lyase (PAL) activities in Dionaea and Nepenthes were higher in the trap than in the leaf while the opposite was found in Drosera. Soluble phenols and majority of phenolic acids were mainly accumulated in the trap among species. Flavonoids were abundant in Drosera and Dionaea traps but not in Nepenthes. Phenolic acids were preferentially accumulated in a glycosidically-bound form and gallic acid was the main metabolite. Green tea contained more soluble phenols and phenolic acids but less quercetin. In vitro experiments with Drosera spathulata revealed that nitrogen deficiency enhances PAL activity, accumulation of phenols and sugars while PAL inhibitor (2-aminoindane-2-phosphonic acid) depleted phenols and some amino acids (but free phenylalanine and sugars were elevated). Possible explanations in physiological, biochemical and ecological context are discussed. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Synthesis of d- and l-Phenylalanine Derivatives by Phenylalanine Ammonia Lyases: A Multienzymatic Cascade Process**

Science.gov (United States)

Parmeggiani, Fabio; Lovelock, Sarah L; Weise, Nicholas J; Ahmed, Syed T; Turner, Nicholas J

2015-01-01

The synthesis of substituted d-phenylalanines in high yield and excellent optical purity, starting from inexpensive cinnamic acids, has been achieved with a novel one-pot approach by coupling phenylalanine ammonia lyase (PAL) amination with a chemoenzymatic deracemization (based on stereoselective oxidation and nonselective reduction). A simple high-throughput solid-phase screening method has also been developed to identify PALs with higher rates of formation of non-natural d-phenylalanines. The best variants were exploited in the chemoenzymatic cascade, thus increasing the yield and ee value of the d-configured product. Furthermore, the system was extended to the preparation of those l-phenylalanines which are obtained with a low ee value using PAL amination. PMID:25728350

Methyl Jasmonate and Salicylic Acid Induced Oxidative Stress and Accumulation of Phenolics in Panax ginseng Bioreactor Root Suspension Cultures

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Kee-Yoeup Paek

2007-03-01

Full Text Available To investigate the enzyme variations responsible for the synthesis of phenolics, 40 day-old adventitious roots of Panax ginseng were treated with 200 μM methyl jasmonate (MJ or salicylic acid (SA in a 5 L bioreactor suspension culture (working volume 4 L. Both treatments caused an increase in the carbonyl and hydrogen peroxide (H2O2 contents, although the levels were lower in SA treated roots. Total phenolic, flavonoid, ascorbic acid, non-protein thiol (NPSH and cysteine contents and 1,1-diphenyl-2-picrylhydrazyl (DPPH radical reducing activity were increased by MJ and SA. Fresh weight (FW and dry weight (DW decreased significantly after 9 days of exposure to SA and MJ. The highest total phenolics (62%, DPPH activity (40%, flavonoids (88%, ascorbic acid (55%, NPSH (33%, and cysteine (62% contents compared to control were obtained after 9 days in SA treated roots. The activities of glucose 6-phosphate dehydrogenase, phenylalanine ammonia lyase, substrate specific peroxidases (caffeic acid peroxidase, quercetin peroxidase and ferulic acid peroxidase were higher in MJ treated roots than the SA treated ones. Increased shikimate dehydrogenase, chlorogenic acid peroxidase and β-glucosidase activities and proline content were observed in SA treated roots than in MJ ones. Cinnamyl alcohol dehydrogenase activity remained unaffected by both MJ and SA. These results strongly indicate that MJ and SA induce the accumulation of phenolic compounds in ginseng root by altering the phenolic synthesis enzymes.

Levels of potential bioactive compounds including carotenoids, vitamin C and phenolic compounds, and expression of their cognate biosynthetic genes vary significantly in different varieties of potato (Solanum tuberosum L.) grown under uniform cultural conditions.

Science.gov (United States)

Valcarcel, Jesus; Reilly, Kim; Gaffney, Michael; O'Brien, Nora M

2016-02-01

In addition to their high carbohydrate content, potatoes are also an important dietary source of vitamin C and bioactive secondary metabolites, including phenolic compounds and carotenoids, which have been suggested to play a role in human health. The expression of genes encoding key enzymes involved in the synthesis of these compounds was assessed by reverse transcription-quantitative polymerase chain reaction and compared to the accumulation of the corresponding product in seven potato varieties showing contrasting levels of metabolite accumulation. Strong positive correlations were found between phenolic content in the flesh of tubers and transcript levels of phenylalanine ammonia lyase (PAL) and chalcone synthase (CHS) genes. The expression of PAL and CHS was also related to that of AN1, a transcription factor involved in the synthesis of anthocyanins, suggesting that these genes are regulated in a coordinated manner. No clear relationship was found between transcript levels of phytoene synthase (PSY) or L-galactono-1,4-lactone dehydrogenase (GLDH) genes and total carotenoid or vitamin C accumulation, respectively. Data indicate that levels of total phenolic and flavonoid compounds in potato are controlled primarily by PAL and CHS gene expression. Transcript levels of PSY and GLDH did not control accumulation of carotenoids or vitamin C. © 2015 Society of Chemical Industry.

XPS and NEXAFS study of tyrosine-terminated propanethiol assembled on gold

CERN Document Server

Petoral, R M

2003-01-01

Tyrosine-terminated propanethiol (TPT), tyrosine linked to 3-mercaptopropionic acid through an amide bond, is adsorbed to gold surfaces. The adsorbates are characterized by means of X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure spectroscopy (NEXAFS). XPS is used to investigate the chemical binding and electronic structure of the monolayer. Strong molecular binding of the tyrosine derivative on the gold surface through the sulfur atom is attained. Angle-dependent XPS results shows that TPT molecules are oriented with the sulfur atoms molecularly oriented close to the gold surface and that the phenol moiety is oriented away from the gold surface. Average orientation of the adsorbate on gold is deduced using the NEXAFS results. It shows that the main molecular axis is tilted approximately 38 deg. relative to the Au surface normal. The ring plane of the phenol moiety exhibits a preferential orientation with an average tilt angle of the normal of the ring plane from the surfa...

Wild Roman chamomile extracts and phenolic compounds: enzymatic assays and molecular modelling studies with VEGFR-2 tyrosine kinase

OpenAIRE

Guimarães, Rafaela; Calhelha, Ricardo C.; Froufe, Hugo J.C.; Abreu, Rui M.V.; Carvalho, Ana Maria; Queiroz, Maria João R.P.; Ferreira, Isabel C.F.R.

2016-01-01

Angiogenesis is a process by which new blood vessels are formed from the pre-existing vasculature, and it is a key process that leads to tumour development. Some studies have recognized phenolic compounds as chemopreventive agents; flavonoids, in particular, seem to suppress the growth of tumor cells modifying the cell cycle. Herein, the antiangiogenic activity of Roman chamomile (Chamaemelum nobile L.) extracts (methanolic extract and infusion) and the main phenolic compounds present (apigen...

Production of manganese peroxidase by white rot fungi from potato ...

African Journals Online (AJOL)

phenylalanine and L-tyrosine blocked the MnP biosynthetic pathway. Ammonium ion released from the L-phenylalanine by the L-phenylalanine ammonia-lyase participated in the repression of the MnP biosynthetic pathway of the strain L-25.

Content of Phenolic Compounds in the Genus Carduus L. from Bulgaria

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Iliya Zhelev

2013-12-01

Full Text Available Phytochemical screening of the content of total polyphenols, flavonoids, phenolic acids and anthocyanins in Bulgarian Carduus L. species was carried out. The plant materials (inflorescences from all of the 14 species found in Bulgaria has been collected from natural habitats from different floristic regions, during the period 2011-2013. Chemical analysis of the specimens was carried out in accordance with 11 Russian and 7 European Pharmacopoeia. For some of the plant species the obtained results are the first published data about content of phenolic compounds. The content of flavonoids (1,8-3,2% and total phenols(1,7-2,3% was higher in comparison with this of phenolic acids (0,6-2,4% and anthocyanins (0,5-1,5%. The highest content of total phenols and antocyanins was determined in the Carduus thracicus. The three species Carduus thoermeri, Carduus nutans and Carduus candicans ssp. globifer were characterized with the highest content of flavonoids. The highest content of phenolic acids was determined in the Carduus armatus.

The effect of cadmium on phenylalanine ammonia lyase activity and lipid peroxidation in pepper (Capsicum annuum L. seedlings

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Esra Koç

2015-04-01

Full Text Available In this study, the effect on differrent concentrations (20, 40, 80µM ve 100 µM CdCl2 of cadmium (CdCl2 on the activity of phenylalanine ammonia-lyase (PAL and lipid peroxidation amount in leaf and stem of Kahramanmaraş- Hot (Capsicum annum L. pepper seedlings were researched. Activity of phenylalanine ammonia-lyase (PAL, the first enzyme in the phenylpropanoid biosynthetic pathway, was increased at 2 and 4 days in KM-Hot plants exposed to CdCl2 stress. The highest PAL activity was detected in 20 μM CdCl2 application, on the four day after the application in the leaves of KM-Hot pepper. Moreover, it was observed that treatment of pepper with Cd led to an increased the rate of lipid peroxidation (which is indicated by increasing MDA content in the leaf and stem tissues. The highest MDA content was detected in 80 μM CdCl2 application, on the four day after the application in the leaf tissues. These results suggest that the activation of PAL may be associated with increased production of MDA

Towards the conception of an amperometric sensor of L-tyrosine based on Hemin/PAMAM/MWCNT modified glassy carbon electrode

International Nuclear Information System (INIS)

Ma Qiang; Ai Shiyun; Yin Huanshun; Chen Quanpeng; Tang Tiantian

2010-01-01

A novel amperometric sensor was fabricated based on the immobilization of hemin onto the poly (amidoamine)/multi-walled carbon nanotube (PAMAM/MWCNT) nanocomposite film modified glassy carbon electrode (GCE). Electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and ultraviolet visible (UV-vis) adsorption spectroscopy were used to investigate the possible state and electrochemical activity of the immobilized hemin. In the Hemin/PAMAM/MWCNT nanocomposite film, MWCNT layer possessed excellent inherent conductivity to enhance the electron transfer rate, while the layer of PAMAM greatly enlarged the surface average concentration of hemin (Γ) on the modified electrode. Therefore, the nanocomposite film showed enhanced electrocatalytical activity towards the oxidation of L-tyrosine. The kinetic parameters of the modified electrode were investigated. In pH 7.0 phosphate buffer solution (PBS), the sensor exhibits a wide linear range from 0.1 μM to 28.8 μM L-tyrosine with a detection limit of 0.01 μM and a high sensitivity of 0.31 μA μM -1 cm -2 . In addition, the response time of the L-tyrosine sensor is less than 5 s. The excellent performance of the sensor is largely attributed to the electro-generated high reactive oxoiron (IV) porphyrin (O = Fe IV -P) which effectively catalyzed the oxidation of L-tyrosine. A mechanism was herein proposed for the catalytic oxidation of L-tyrosine by oxoiron (IV) porphyrin complexes.

The relation of putamen nucleus 6-[18F]fluoro-L-m-tyrosine uptake to total Unified Parkinson's Disease Rating Scale scores

International Nuclear Information System (INIS)

Buchy, R.

2002-01-01

The contribution of dopaminergic deficiency in the striatum to the severity of locomotor disability in Parkinson's disease has been consistently shown with 6-[ 18 F]fluoro-L-DOPA in positron emission tomography. Recently, 6-[ 18 F]fluoro-L-m-tyrosine, an alternative tracer with similar distribution kinetics has been used to facilitate data analysis. Locomotor disability in Parkinson's disease can be measured using the Unified Parkinson's Disease Rating Scale. The Unified Parkinson's Disease Rating Scale was used in conjunction with 6-[ 18 F]fluoro-L-m-tyrosine -PET to clinically examine a group of five Parkinson's disease patients. An inverse relation similar to that previously demonstrated with 6-[ 18 F]fluoro-L-DOPA was found between the putamen nucleus 6-[ 18 F]fluoro-L-m-tyrosine influx constant and Unified Parkinson's Disease Rating Scale score. This finding suggests that like 6-[ 18 F]fluoro-L-m-tyrosine can be used to accurately measure the degree of locomotor disability caused by Parkinson's disease. (author)

A radiometric technique for the measurement of adenylosuccinate lyase

International Nuclear Information System (INIS)

Park, K.W.; Tyagi, A.K.; Cooney, D.A.

1980-01-01

When radioactive adenylosuccinic acid (AMP-S) is metabolized to AMP and fumaric acid by the enzyme adenylosuccinate lyase (EC 4.3.2.2), a proton is released to the solvent as 3 H 2 O. This removal is believed to be stereospecifically identical to that catalyzed by the enzyme, L-aspartase, and therefore entails the loss of a proton from C-3 of the dicarboxylic acid moiety of the nucleotide. Advantage has been taken of this fact in the design of a facile assay for this enzyme. The assay permits the simultaneous estimation of the lyase activity in a large battery of samples; it is not interfered with by opalescent or proteinaceous suspensions; it is accurate and outstandingly sensitive. (Auth.)

Bioproduction of L-Aspartic Acid and Cinnamic Acid by L-Aspartate Ammonia Lyase from Pseudomonas aeruginosa PAO1.

Science.gov (United States)

Patel, Arti T; Akhani, Rekha C; Patel, Manisha J; Dedania, Samir R; Patel, Darshan H

2017-06-01

Aspartase (L-aspartate ammonia lyase, EC 4.3.1.1) catalyses the reversible amination and deamination of L-aspartic acid to fumaric acid which can be used to produce important biochemical. In this study, we have explored the characteristics of aspartase from Pseudomonas aeruginosa PAO1 (PA-AspA). To overproduce PA-AspA, the 1425-bp gene was introduced in Escherichia coli BL21 and purified. A 51.0-kDa protein was observed as a homogenous purified protein on SDS-PAGE. The enzyme was optimally active at pH 8.0 and 35 °C. PA-AspA has retained 56% activity after 7 days of incubation at 35 °C, which displays the hyperthermostablility characteristics of the enzyme. PA-AspA is activated in the presence of metal ions and Mg2+ is found to be most effective. Among the substrates tested for specificity of PA-AspA, L-phenylalanine (38.35 ± 2.68) showed the highest specific activity followed by L-aspartic acid (31.21 ± 3.31) and fumarate (5.42 ± 2.94). K m values for L-phenylalanine, L-aspartic acid and fumarate were 1.71 mM, 0.346 μM and 2 M, respectively. The catalytic efficiency (k cat /K m ) for L-aspartic acid (14.18 s -1  mM -1 ) was higher than that for L-phenylalanine (4.65 s -1  mM -1 ). For bioconversion, from an initial concentration of 1000 mM of fumarate and 30 mM of L-phenylalanine, PA-AspA was found to convert 395.31 μM L-aspartic acid and 3.47 mM cinnamic acid, respectively.

Kinetic and thermodynamic properties of alginate lyase and cellulase co-produced by Exiguobacterium species Alg-S5.

Science.gov (United States)

Mohapatra, Bidyut R

2017-05-01

In an effort to screen out the alginolytic and cellulolytic bacteria from the putrefying invasive seaweed Sargassum species accumulated off Barbados' coast, a potent bacterial strain was isolated. This bacterium, which simultaneously produced alginate lyase and cellulase, was identified as Exiguobacterium sp. Alg-S5 via the phylogenetic approach targeting the 16S rRNA gene. The co-produced alginate lyase and cellulase exhibited maximal enzymatic activity at pH 7.5 and at 40°C and 45°C, respectively. The K m and V max values recorded as 0.91mg/mL and 21.8U/mg-protein, respectively, for alginate lyase, and 10.9mg/mL and 74.6U/mg-protein, respectively, for cellulase. First order kinetic analysis of the thermal denaturation of the co-produced alginate lyase and cellulase in the temperature range from 40°C to 55°C revealed that both the enzymes were thermodynamically efficient by displaying higher activation energy and enthalpy of denaturation. These enzymatic properties indicate the potential industrial importance of this bacterium in algal biomass conversion. This appears to be the first report on assessing the efficacy of a bacterium for the co-production of alginate lyase and cellulase. Copyright © 2017 Elsevier B.V. All rights reserved.

A new precursor for the preparation of 6-[18F]-fluoro-L-m-tyrosine (FMT): Efficient synthesis and comparison of radiolabeling

International Nuclear Information System (INIS)

VanBrocklin, Henry F.; Blagoev, Milan; Hoepping, Alexander; O'Neil, James P.; Klose, Manuela; Schubiger, Pius A.; Ametamey, Simon

2004-01-01

For the electrophilic preparation of 6-[18F]-Fluoro-L-m-tyrosine (FMT), a PET tracer for measuring changes in dopaminergic function in movement disorders, a novel precursor, N-(tert-butoxycarbonyl)-3- (tert-butoxycarbonyloxy)-6-trimethylstannnyl-L-pheny-lalanine ethyl ester, was synthesized in four steps and 26 percent yield starting from L-m-tyrosine. FMT produced by two methods at two institutions was comparable in decay corrected yield, 25-26 percent, and quality (chemical, enantiomeric, and radiochemical purity and specific activity) as that obtained with the original N-trifluoroacetyl-3-acetyl-6-trimethylstannyl-L-m-tyrosine ethyl ester FMT precursor

Investigation of Phenolic Compounds and Antioxidant Activity of Mentha spicata L. subsp. spicata and M. longifolia (L.) L. subsp. typhoides (Briq.) Harley Decoction and Infusion

OpenAIRE

ÖZER, Züleyha

2018-01-01

In present study, we report phenolic compounds and antioxidant activity of decoctionand infusion of Mentha spicata L. subsp. spicataand M. longifolia (L.) L. subsp. typhoides (Briq.) Harley. The quantitativeamounts of the phenolic contents were determined by LC-MS/MS.  The main compounds and amounts of M. spicata weredetermined as follow for decoction; caffeic acid, quercetagetin-3,6-dimethyletherand penduletin (4126.6; 2141.5; 1472.7 mg/kg dried herba, respectively), for infusion;fumaric aci...

Comparison of the uptake of [123/125I]-2-iodo-D-tyrosine and [123/125I]-2-iodo-L-tyrosine in R1M rhabdomyosarcoma cells in vitro and in R1M tumor-bearing Wag/Rij rats in vivo

International Nuclear Information System (INIS)

Bauwens, Matthias; Lahoutte, Tony; Kersemans, Ken; Gallez, Carol; Bossuyt, Axel; Mertens, John

2006-01-01

Introduction: Recently, promising results concerning uptake in vivo in tumors of D-amino acids have been published. Therefore, we decided to evaluate the tumor uptake of the D-analogue of [ 123 I]-2-iodo-L-tyrosine, a tracer recently introduced by our group into clinical trials. The uptake of 2-amino-3-(4-hydroxy-2-[ 123/125 I]iodophenyl)-D-propanoic acid (2-iodo-D-tyrosine) was studied in vitro in LAT1-expressing R1M rat rhabdomyosarcoma cells and in vivo in R1M tumor-bearing Wag/Rij rats. Methods: The uptake of [ 125 I]-2-iodo-L-tyrosine and [ 125 I]-2-iodo-D-tyrosine into R1M cells was determined in appropriate buffers, allowing the study of the involved transport systems. In vivo, the biodistribution in R1M-bearing rats of [ 123 I]-2-iodo-L-tyrosine and [ 123 I]-2-iodo-D-tyrosine was performed by both dynamic and static planar imaging with a gamma camera. Results: In in vitro conditions, the uptake of both [ 125 I]-2-iodo-L-tyrosine and [ 125 I]-2-iodo-D-tyrosine in the HEPES buffer was 25% higher in the presence of Na + ions. In the absence of Na + ions, [ 125 I]-2-iodo-D-tyrosine was taken up reversibly in the R1M cells, with an apparent accumulation, probably for the larger part by the LAT1 system. Dynamic planar imaging showed that the uptake in the tumors of [ 123 I]-2-iodo-D-tyrosine was somewhat lower than that of [ 123 I]-2-iodo-L-tyrosine. At 30 min postinjection, the mean differential uptake ratio values of the L- and D-enantiomers are 2.5±0.7 and 1.7±0.6, respectively. Although the uptake of the D-isomer is lower, probably due to a faster clearance from the blood, the tumor-background ratio is the same as that of the L-analogue. Conclusion: A large part (75%) of [ 125 I]-2-iodo-D-tyrosine in vitro and [ 123 I]-2-iodo-D-tyrosine in vivo is reversibly highly taken up in R1M tumor cells by Na + -independent LAT transport systems, more likely by the LAT1. The clearance from the blood of [ 123 I]-2-iodo-D-tyrosine in the rats is faster than that of the

Synthesis of O-(2-[18F]fluoroethyl)-L-tyrosine based on a cartridge purification method

International Nuclear Information System (INIS)

Mueller, Dirk; Klette, Ingo; Kalb, Fabrizia; Baum, Richard P.

2011-01-01

Introduction: O-(2-[ 18 F]fluoroethyl)-L-tyrosine (FET) is widely used as a positron emission tomography tracer for brain tumors. Usually, a high-performance liquid chromatography (HPLC) purification at the end of the two-step synthesis is applied. In this work, we report an automatic radiosynthesis of FET with a purification procedure based on standard cartridges. Methods: O-(2-[ 18 F]fluoroethyl)-L-tyrosine was prepared by [ 18 F]fluoroethylation of L-tyrosine by a two-step synthesis using a modified [ 11 C]methionine module (Nuclear Interface). In the first reaction step, we synthesized [ 18 F]fluoroethyltosylate starting from [ 18 F]fluoride. After a purification step, L-tyrosine was [ 18 F]fluoroethylated with [ 18 F]fluoroethyltosylate. The final reaction mixture was purified by means of solid phase extraction. The FET was trapped on an SCX cartridge, eluted with saline solution and trapped again on an HRX cartridge. For a second purification step, the FET was eluted from the HRX cartridge with ammonium acetate buffer and collected on two SCX cartridges followed by a washing step with water. The final product was eluted with saline solution and neutralised with 450 μl NaHCO 3 solution (8.4%). Results: The synthesis was finished after 50 min and delivered the FET in a range of 3-16 GBq. The synthesis typically yielded 41% (21 experiments) of FET (d.c.) without an HPLC purification step. The radiochemical purity ranged between 97% and 100%. Conclusion: We present a radiosynthesis of FET where the usually used HPLC purification procedure has been substituted by a purification step based on standard cartridges. This method is useful for automatic modules without an expensive HPLC purification unit and for the routine production of FET.

All-trans-retinoic acid enhances apoptosis induction by tyrosine kinase inhibitors in the eosinophilic leukemia-derived EoL-1 cell line.

Science.gov (United States)

Robert, Carine; Apàti, Agota; Chomienne, Christine; Papp, Béla

2008-02-01

Imatinib and retinoids induce apoptosis in FIP1L1/PDGFRalpha-positive EoL-1 leukemia cells. Although imatinib induces complete remission in most FIP1L1/PDGFRalpha-positive patients, response to imatinib is sometimes suboptimal. In order to enhance the potency of the molecularly targeted therapy of eosinophilic leukemia, we investigated the effect of retinoids combined with tyrosine kinase inhibitors on EoL-1 cells. We demonstrate that retinoids combined with tyrosine kinase inhibitors lead to enhanced apoptosis induction in EoL-1 cells. Our results suggest that tyrosine kinase inhibitors combined with retinoids may constitute a valuable therapeutic approach for sensitive neoplasias that may display enhanced anti-leukemic potency when compared to single drug treatments.

Phenolic compounds and biological activity of Capsicum annuum L ...

African Journals Online (AJOL)

The objective of this study was to evaluate antifungal and antioxidant activities of vegetable extracts (Capsicum annuum L. cv. Dora, cv. Strizanka, cv. Morava), grown in Serbia. Different experimental models have included the determination content of total phenolics, total flavonoids, antioxidant capacity and minimum ...

The mechanism of the tyrosine transporter TyrP supports a proton motive tyrosine decarboxylation pathway in Lactobacillus brevis

NARCIS (Netherlands)

Wolken, WAM; Lucas, PM; Lonvaud-Funel, A; Lolkema, JS; Wolken, Wout A.M.; Lucas, Patrick M.

The tyrosine decarboxylase operon of Lactobacillus brevis IOEB9809 contains, adjacent to the tyrosine decarboxylase gene, a gene for TyrP, a putative tyrosine transporter. The two genes potentially form a proton motive tyrosine decarboxylation pathway. The putative tyrosine transporter gene of L.

Possible regulation of sterol biosynthesis by phenolic acids

International Nuclear Information System (INIS)

Ranganathan, S.; Ramasarma, T.

1974-01-01

To test whether the phenolic acids, metabolites of tyrosine, regulate the biosynthesis of cholesterol, influence of phenolic acids on the incorporation of mevalonate-2- 14 C into sterols by rat liver and brain homogenate systems has been investigated in vitro. Results show that the combined presence of the aromatic ring and the carboxyl group in the compound under investigation inhibited the incorporation of labelled mevalonate. (M.G.B.)

Solvent 1H/2H isotopic effects in the reaction of the L-Tyrosine oxidation catalyzed by Tyrosinase

International Nuclear Information System (INIS)

Kozlowska, M.; Kanska, M.

2006-01-01

Tyrosinase is well known catalyst in the oxidation of L-Tyrosine to L-DOPA and following oxidation of L-DOPA to dopachinone. The aim of communication is to present the results of studies on the solvent isotopic effects (SIE) in the above reactions for the 1 H/ 2 H in the 3',5' and 2',6' substituted tyrosine. Obtained dependence of the reaction rate on the substrate concentration were applied for optimization of the kinetic parameters, k cat and k cat /K m , in the Michaelis-Menten equation. As a result - better understanding of the L-DOPA creation can be achieved

Tyrosine and carboxyl protonation changes in the bacteriorhodopsin photocycle. 1. M412 and L550 intermediates

International Nuclear Information System (INIS)

Roepe, P.; Ahl, P.L.; Gupta, S.K.D.; Herzfeld, J.; Rothschild, K.J.

1987-01-01

The role of tyrosines in the bacteriorhodopsin (bR) photocycle has been investigated by using Fourier transform infrared (FTIR) and UV difference spectroscopies. Tyrosine contributions to the BR 570 → M 412 FTIR difference spectra recorded at several temperatures and pH's were identified by isotopically labeling tyrosine residues in bacteriorhodopsin. The frequencies and deuterium/hydrogen exchange sensitivities of these peaks and of peaks in spectra of model compounds in several environments suggest that at least two different tyrosine groups participate in the bR photocycle during the formation of M 412 . One group undergoes a tyrosinate → tyrosine conversion during the BR 570 → K 630 transition. A second tyrosine group deprotonates between L 550 and M 412 . Low-temperature UV difference spectra in the 220-350-nm region of both purple membrane suspensions and rehydrated films support these conclusions. The UV spectra also indicate perturbations(s) of one or more tryptophan group(s). Several carboxyl groups appear to undergo a series of protonation changes between BR 570 and M 412 , as indicated by infrared absorption changes in the 1770-1720-cm -1 region. These results are consistent with the existence of a proton wire in bacteriorhodopsin that involves both tyrosine and carboxyl groups

Amino phenolics from the fruit of the argan tree Argania spinosa (Skeels L.).

Science.gov (United States)

Klika, D; Khallouki, Farid; Owen, Robert W

2014-01-01

A new phenolic-type compound containing a nitrogenous, heterocyclic-fused ring from the fruit of the argan tree, Argania spinosa (Skeels L.), is described. This and another already known compound also isolated in the course of the work belong to an obscure and rare class of natural products, the amino phenolics.

Partial Purification and Characterization of a Thermostable β-Mannanase from Aspergillus foetidus

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Juliana da Conceição Infante de Marco

2015-10-01

Full Text Available An extracellular β-mannanase was isolated from samples of crude extract of the mesophilic fungus Aspergillus foetidus grown on soybean husk as a carbon source. The induction profile showed that β-mannanase reached a maximum activity level (2.0 IU/mL on the 15th day of cultivation. The enzyme was partially purified by ultrafiltration and gel filtration chromatography procedures and was named Man 58. Sodium dodecyl sulfate-polyacrilamide electrophoresis and zymogram analysis of Man 58 showed two bands of approximately 43 and 45 kDa with β-mannanase activity. Ultrafiltration showed that β-mannanase activity was only detected in the concentrated sample. Man 58 was most active at 60 °C and at pH 4.0. It was thermostable in the temperature range of 40–60 °C for eleven days, and the half-life at 70 °C was ten days. Man 58 showed Km and Vmax values of 3.29 mg/mL and 1.76 IU/mL respectively, with locust bean gum as a substrate. It was mostly activated by FeSO4 and CoCl2 and inhibited by MgSO4, FeCl3, CuSO4, MgCl2, ZnCl2, ZnSO4, CaCl2, CuCl2, KCl and ethylenediaminetetraacetic acid (EDTA. Phenolic compounds did not inhibit the enzyme. On the other hand, auto-hydrolysis liquor showed an inhibitory effect on Man 58 activity.

Antioxidant activity of phenolic compounds in lentil seeds (Lens culinaris L.

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Dragišić-Maksimović Jelena

2010-01-01

Full Text Available The antioxidant activities of methanol extracts of lentil seeds (Lens culinaris L. have been investigated in this work. Scarce reference data describe lentil seeds as rich in polyphenols, which are reported to exhibit bioactive properties due to their capability to reduce or quench reactive oxygen species. The content and composition of phenolics is highly dependent of the cultivars, environments/growth conditions and method of analysis. Therefore, this study is an effort in investigation of phenolics content and composition in lentil seeds trying to prove the contribution of identified phenolics to antioxidant capacity. HPLC measurements revealed that lentil seeds contain gallic acid, epicatechin, catechin, protocatechuic acid, rutin, p-coumaric acid and umbeliferone. Their DPPH radical scavenging activity was in descending order from gallic acid to umbeliferone. The presented results contribute to knowledge of the implications in dietary intake of phenolic compounds from lentil seeds.

Tyr51: Key Determinant of the Low Thermostability of the Colwellia psychrerythraea Cold-Shock Protein.

Science.gov (United States)

Lee, Yeongjoon; Kwak, Chulhee; Jeong, Ki-Woong; Durai, Prasannavenkatesh; Ryu, Kyoung-Seok; Kim, Eun-Hee; Cheong, Chaejoon; Ahn, Hee-Chul; Kim, Hak Jun; Kim, Yangmee

2018-05-18

Cold-shock proteins (Csps) are expressed at lower-than-optimum temperatures, and they function as RNA chaperones; however, no structural studies on psychrophilic Csps have been reported. Here, we aimed to investigate the structure and dynamics of the Csp of psychrophile Colwellia psychrerythraea 34H, ( Cp-Csp). Although Cp-Csp shares sequence homology, common folding patterns, and motifs, including a five β-stranded barrel, with its thermophilic counterparts, its thermostability (37 °C) was markedly lower than those of other Csps. Cp-Csp binds heptathymidine with an affinity of 10 -7 M, thereby increasing its thermostability to 50 °C. Nuclear magnetic resonance spectroscopic analysis of the Cp-Csp structure and backbone dynamics revealed a flexible structure with only one salt bridge and 10 residues in the hydrophobic cavity. Notably, Cp-Csp contains Tyr51 instead of the conserved Phe in the hydrophobic core, and its phenolic hydroxyl group projects toward the surface. The Y51F mutation increased the stability of hydrophobic packing and may have allowed for the formation of a K3-E21 salt bridge, thereby increasing its thermostability to 43 °C. Cp-Csp exhibited conformational exchanges in its ribonucleoprotein motifs 1 and 2 (754 and 642 s -1 ), and heptathymidine binding markedly decreased these motions. Cp-Csp lacks salt bridges and has longer flexible loops and a less compact hydrophobic cavity resulting from Tyr51 compared to mesophilic and thermophilic Csps. These might explain the low thermostability of Cp-Csp. The conformational flexibility of Cp-Csp facilitates its accommodation of nucleic acids at low temperatures in polar oceans and its function as an RNA chaperone for cold adaptation.

Identification of Phenolic Compounds and Evaluation of Antioxidant and Antimicrobial Properties of Euphorbia Tirucalli L.

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Keline Medeiros de Araújo

2014-03-01

Full Text Available Bioactive compounds extracted from natural sources can benefit human health. The aim of this work was to determine total phenolic content and antioxidant activity in extracts of Euphorbia tirucalli L. followed by identification and quantification of the phenolic compounds, as well as their antibacterial activities. Antioxidant activities were determined by DPPH and ABTS•+ assay. Identification of phenolic compounds was performed using high-performance liquid chromatography (HPLC, and antimicrobial activities were verified by agar dilution methods and MIC values. Total phenolic content ranged from 7.73 to 30.54 mg/100 g gallic acid equivalent. Extracts from dry plants showed higher antioxidant activities than those from fresh ones. The DPPH EC50 values were approximately 12.15 μg/mL and 16.59 μg/mL, respectively. Antioxidant activity measured by the ABTS method yielded values higher than 718.99 μM trolox/g for dry plants, while by the Rancimat® system yielded protection factors exceeding 1 for all extracts, comparable to synthetic BHT. Ferulic acid was the principal phenolic compound identified and quantified through HPLC-UV in all extracts. The extracts proved effective inhibitory potential for Staphylococcus epidermidis and Staphylococcus aureus. These results showed that extracts of Euphorbia tirucalli L. have excellent antioxidant capacity and moderate antimicrobial activity. These can be attributed to the high concentration of ferulic acid.

Simple automated preparation of O-[{sup 11}C]methyl-L-tyrosine for routine clinical use

Energy Technology Data Exchange (ETDEWEB)

Ishikawa, Yoichi [CYRIC Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578 (Japan); Iwata, Ren [CYRIC Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578 (Japan)]. E-mail: rencyric@cyric.tohoku.ac.jp; Furumoto, Shozo [TUBERO, Tohoku University, Sendai 980-8575 (Japan); Pascali, Claudio [National Cancer Institute, 20133 Milan (Italy); Bogni, Anna [National Cancer Institute, 20133 Milan (Italy); Kubota, Kazuo [International Medical Center, Tokyo 162-8655 (Japan); Ishiwata, Kiichi [Tokyo Metropolitan Institute of Gerontology, Tokyo 173-0022 (Japan)

2005-07-01

The previously reported preparation of O-[{sup 11}C]methyl-L-tyrosine ([{sup 11}C]MT), a promising tumor imaging agent, has been now considerably simplified and automated. Main changes were the use of [{sup 11}C]methyl iodide ([{sup 11}C]MeI) in the reaction with L-tyrosine disodium and the use of solid phase extraction on commercially available cartridges instead of HPLC for the final purification. An injectable saline solution of [{sup 11}C]MT was obtained within 30 min after EOB with radiochemical yield of ca. 60% (decay-corrected, based on [{sup 11}C]MeI). Radiochemical purity was over 97%. The automated preparation was carried out using a miniature module employing manifold valves.

Changes in antioxidant and biochemical activities in castor oil-coated Capsicum annuum L. during postharvest storage.

Science.gov (United States)

Panigrahi, Jitendriya; Patel, Mansi; Patel, Niyati; Gheewala, Bhumi; Gantait, Saikat

2018-06-01

This study, for the first time, evaluates the efficiency of castor oil when used as an external coating on Capsicum annuum L., to increase postharvest storage-life at 4 ± 1 °C. The castor oil-coated fruits were successfully stored for 36 days, while the non-coated fruits could only sustain for 18 days. Throughout the storage period (at 9-day intervals), different antioxidants and biochemical assays (allied with storage) such as titratable acidity, ascorbic acid content, ferrous ion chelating activity, reducing power, DPPH scavenging activity, hydroxyl radical scavenging activity, total phenolic content, total sugar estimation, and enzymatic study of polyphenol oxidase and pectate lyase, were assessed. During storage, the castor oil-coated fruits showed a substantial decrease in titratable acidity, ascorbic acid content, total phenolic content, including antioxidant activities such as reducing power and DPPH activity; however, an increase in ferrous ion chelating activity, total soluble sugar content, polyphenol oxidase activity and initial pectate lyase activity was observed, in contrast to that of the non-coated fruits. The application of castor oil proved to be effective in delaying the ripening process of fruits during storage.

Combinatorial analysis of enzymatic bottlenecks of L-tyrosine pathway by p-coumaric acid production in Saccharomyces cerevisiae.

Science.gov (United States)

Mao, Jiwei; Liu, Quanli; Song, Xiaofei; Wang, Hesuiyuan; Feng, Hui; Xu, Haijin; Qiao, Mingqiang

2017-07-01

To identify new enzymatic bottlenecks of L-tyrosine pathway for further improving the production of L-tyrosine and its derivatives. When ARO4 and ARO7 were deregulated by their feedback resistant derivatives in the host strains, the ARO2 and TYR1 genes, coding for chorismate synthase and prephenate dehydrogenase were further identified as new important rate-limiting steps. The yield of p-coumaric acid in the feedback-resistant strain overexpressing ARO2 or TYR1, was significantly increased from 6.4 to 16.2 and 15.3 mg l -1 , respectively. Subsequently, we improved the strain by combinatorial engineering of pathway genes increasing the yield of p-coumaric acid by 12.5-fold (from 1.7 to 21.3 mg l -1 ) compared with the wild-type strain. Batch cultivations revealed that p-coumaric acid production was correlated with cell growth, and the formation of by-product acetate of the best producer NK-M6 increased to 31.1 mM whereas only 19.1 mM acetate was accumulated by the wild-type strain. Combinatorial metabolic engineering provides a new strategy for further improvement of L-tyrosine or other metabolic biosynthesis pathways in S. cerevisiae.

Quantitative and Qualitative Analysis of Phenolic and Flavonoid Content in Moringa oleifera Lam and Ocimum tenuiflorum L.

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Sankhalkar, Sangeeta; Vernekar, Vrunda

2016-01-01

Number of secondary compounds is produced by plants as natural antioxidants. Moringa oleifera Lam. and Ocimum tenuiflorum L. are known for their wide applications in food and pharmaceutical industry. To compare phenolic and flavonoid content in M. oleifera Lam and O. tenuiflorum L. by quantitative and qualitative analysis. Phenolic and flavonoid content were studied spectrophotometrically and by paper chromatography in M. oleifera Lam. and O. tenuiflorum L. Higher phenolic and flavonoid content were observed in Moringa leaf and flower. Ocimum flower showed higher phenolic content and low flavonoid in comparison to Moringa. Flavonoids such as biflavonyl, flavones, glycosylflavones, and kaempferol were identified by paper chromatography. Phytochemical analysis for flavonoid, tannins, saponins, alkaloids, reducing sugars, and anthraquinones were tested positive for Moringa and Ocimum leaf as well as flower. In the present study higher phenolic and flavonoid content, indicated the natural antioxidant nature of Moringa and Ocimum signifying their medicinal importance. Moringa oleifera Lam. and Ocimum tenuiflorum L. are widly grown in India and are known for their medicinal properties. Number of secondary metabolites like phenolics and flavonoids are known to be present in both the plants. The present study was conducted with an objective to qualitatively and quantitatively compare the phenolics and flavanoids in these two medicinally important plants.Quantitation of total phenolics and flavanoids was done by spectrophotometrically while qualitative analysis was perfomed by paper chromatography and by phytochemical tests. Our results have shown higher phenolics and flavanoid content in Moringa leaf and flower. However, higher phenolic content was absent in Ocimum flower compared to that of Moringa. Phytochemical analysis of various metabolites such as flavonoids, tanins, sapponins, alkaloids, anthraquinones revealed that both the plant extracts were rich sources of

Proton-Coupled Electron Transfer and a Tyrosine-Histidine Pair in a Photosystem II-Inspired β-Hairpin Maquette: Kinetics on the Picosecond Time Scale.

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Pagba, Cynthia V; McCaslin, Tyler G; Chi, San-Hui; Perry, Joseph W; Barry, Bridgette A

2016-02-25

Photosystem II (PSII) and ribonucleotide reductase employ oxidation and reduction of the tyrosine aromatic ring in radical transport pathways. Tyrosine-based reactions involve either proton-coupled electron transfer (PCET) or electron transfer (ET) alone, depending on the pH and the pKa of tyrosine's phenolic oxygen. In PSII, a subset of the PCET reactions are mediated by a tyrosine-histidine redox-driven proton relay, YD-His189. Peptide A is a PSII-inspired β-hairpin, which contains a single tyrosine (Y5) and histidine (H14). Previous electrochemical characterization indicated that Peptide A conducts a net PCET reaction between Y5 and H14, which have a cross-strand π-π interaction. The kinetic impact of H14 has not yet been explored. Here, we address this question through time-resolved absorption spectroscopy and 280-nm photolysis, which generates a neutral tyrosyl radical. The formation and decay of the neutral tyrosyl radical at 410 nm were monitored in Peptide A and its variant, Peptide C, in which H14 is replaced by cyclohexylalanine (Cha14). Significantly, both electron transfer (ET, pL 11, L = lyonium) and PCET (pL 9) were accelerated in Peptide A and C, compared to model tyrosinate or tyrosine at the same pL. Increased electronic coupling, mediated by the peptide backbone, can account for this rate acceleration. Deuterium exchange gave no significant solvent isotope effect in the peptides. At pL 9, but not at pL 11, the reaction rate decreased when H14 was mutated to Cha14. This decrease in rate is attributed to an increase in reorganization energy in the Cha14 mutant. The Y5-H14 mechanism in Peptide A is reminiscent of proton- and electron-transfer events involving YD-H189 in PSII. These results document a mechanism by which proton donors and acceptors can regulate the rate of PCET reactions.

Variations of total phenol, carotenoid, in vitro antioxidant contents, and phenolic profiles of the pulp of five commercial varieties of mango (Mangifera indica L.)

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Mango (Mangifera indica L.) is a tropical fruit crop grown worldwide with widely attributed nutritional and health-promoting properties. Extensive studies have been made of the high concentrations of phenolic antioxidants in mango peel, seeds, and leaves, yet less is known about the phenolic antioxi...

Evaluation of Antioxidant Properties of Phenolics Extracted from Ananas comosus L.

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Adhikarimayum HARIPYAREE

2010-06-01

Full Text Available Phenolics were extracted from the fruit tissues of Ananas comosus L. var. queen, cv. �Meitei Keehom�, a variety of pineapple grown in Manipur, India, after skin peeling, purified and their antioxidant properties were analyzed. The antioxidant properties were assessed based on the ability of fruit phenolics in absolute methanol to scavenge DPPH, superoxide anion radicals and hydroxyl radicals and compared to antioxidant compounds like ascorbic acid and pyragallol. Pineapple fruit phenolics scavenged DPPH, superioxide anion radicals and hydroxyl radicals in a dose dependent way. In DPPH assay, the IC50 values of pineapple phenolics, ascorbic acid and pyragallol were 12.2?g/ml, 17.82?g/ml and 15.92?g/ml respectively. In superoxide anion and hydroxyl radical scavenging activities, the IC50 values of pineapple phenolics were 11.42?g/ml and 55.292?g/ml, for ascorbic acid 49.62?g/ml, 48.52?g/ml and that of pyragallol was 15.672?g/ml and 60.62?g/ml. The IC50 value was lowest in pineapple phenolics than ascorbic acid and pyragallol in DPPH and superoxide anion assays. But it is higher than ascorbic acid and lower than pyragallol in hydroxyl radical assay. The lower the IC50 values, the higher the antioxidant activities. The phenolics extracted from this variety of pineapple exhibit excellent free radical scavenging activity. The result shows that pineapple and its active constituents may be used in further antioxidative therapy.

Evaluation of Antioxidant Properties of Phenolics Extracted from Ananas comosus L.

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Adhikarimayum HARIPYAREE

2010-06-01

Full Text Available Phenolics were extracted from the fruit tissues of Ananas comosus L. var. queen, cv. Meitei Keehom, a variety of pineapple grown in Manipur, India, after skin peeling, purified and their antioxidant properties were analyzed. The antioxidant properties were assessed based on the ability of fruit phenolics in absolute methanol to scavenge DPPH, superoxide anion radicals and hydroxyl radicals and compared to antioxidant compounds like ascorbic acid and pyragallol. Pineapple fruit phenolics scavenged DPPH, superioxide anion radicals and hydroxyl radicals in a dose dependent way. In DPPH assay, the IC50 values of pineapple phenolics, ascorbic acid and pyragallol were 12.2?g/ml, 17.82?g/ml and 15.92?g/ml respectively. In superoxide anion and hydroxyl radical scavenging activities, the IC50 values of pineapple phenolics were 11.42?g/ml and 55.292?g/ml, for ascorbic acid 49.62?g/ml, 48.52?g/ml and that of pyragallol was 15.672?g/ml and 60.62?g/ml. The IC50 value was lowest in pineapple phenolics than ascorbic acid and pyragallol in DPPH and superoxide anion assays. But it is higher than ascorbic acid and lower than pyragallol in hydroxyl radical assay. The lower the IC50 values, the higher the antioxidant activities. The phenolics extracted from this variety of pineapple exhibit excellent free radical scavenging activity. The result shows that pineapple and its active constituents may be used in further antioxidative therapy.

Tyrosine-lipid peroxide adducts from radical termination: para coupling and intramolecular Diels-Alder cyclization.

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Shchepin, Roman; Möller, Matias N; Kim, Hye-young H; Hatch, Duane M; Bartesaghi, Silvina; Kalyanaraman, Balaraman; Radi, Rafael; Porter, Ned A

2010-12-15

Free radical co-oxidation of polyunsaturated lipids with tyrosine or phenolic analogues of tyrosine gave rise to lipid peroxide-tyrosine (phenol) adducts in both aqueous micellar and organic solutions. The novel adducts were isolated and characterized by 1D and 2D NMR spectroscopy as well as by mass spectrometry (MS). The spectral data suggest that the polyunsaturated lipid peroxyl radicals give stable peroxide coupling products exclusively at the para position of the tyrosyl (phenoxy) radicals. These adducts have characteristic (13)C chemical shifts at 185 ppm due to the cross-conjugated carbonyl of the phenol-derived cyclohexadienone. The primary peroxide adducts subsequently undergo intramolecular Diels-Alder (IMDA) cyclization, affording a number of diastereomeric tricyclic adducts that have characteristic carbonyl (13)C chemical shifts at ~198 ppm. All of the NMR HMBC and HSQC correlations support the structure assignments of the primary and Diels-Alder adducts, as does MS collision-induced dissociation data. Kinetic rate constants and activation parameters for the IMDA reaction were determined, and the primary adducts were reduced with cuprous ion to give a phenol-derived 4-hydroxycyclohexa-2,5-dienone. No products from adduction of peroxyls at the phenolic ortho position were found in either the primary or cuprous reduction product mixtures. These studies provide a framework for understanding the nature of lipid-protein adducts formed by peroxyl-tyrosyl radical-radical termination processes. Coupling of lipid peroxyl radicals with tyrosyl radicals leads to cyclohexenone and cyclohexadienone adducts, which are of interest in and of themselves since, as electrophiles, they are likely targets for protein nucleophiles. One consequence of lipid peroxyl reactions with tyrosyls may therefore be protein-protein cross-links via interprotein Michael adducts.

Attainment of unstable β nucleation of glycine in presence of L-tyrosine and its analytical interpretation-A combined approach

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Renuka Devi, K.; Srinivasan, K.

2015-05-01

The ability of L-tyrosine molecules to act as a template and to facilitate the nucleation of unstable β polymorph in the solution has been revealed through in-situ nucleation study. This nucleation of β occurs along with the existing α nucleation at the critical concentration of additive in the solution. The presence of L-tyrosine molecules lowers the inherent barrier that exists for β nucleation in the solution. No nucleation of γ was observed over the entire range of concentrations studied. The molecular recognition capability and stereo selective inhibitory action of the added L-tyrosine molecules towards glycine molecule have been successfully revealed in terms of habit modification observed in the nucleated polymorphs. In the case of α polymorph, L-tyrosine induces a change in the morphology along the enantiopolar -b direction while in the case of β polymorph, habit modification from needle to plate like structure is observed. With the increase in time span, solution mediated phase transformation from β to α polymorph has been observed in the solution. Analytically the nucleation parameters of α and β polymorphs were estimated based on Classical Nucleation Theory. Form of crystallization of the nucleated polymorphs of glycine was confirmed by a powder x-ray diffraction analysis.

21 CFR 582.5920 - Tyrosine.

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2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Tyrosine. 582.5920 Section 582.5920 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS... § 582.5920 Tyrosine. (a) Product. Tyrosine (L- and DL-forms). (b) Conditions of use. This substance is...

Characterization of a Novel Alginate Lyase from Marine Bacterium Vibrio furnissii H1

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Xiaoyan Zhu

2018-01-01

Full Text Available Alginate lyases show great potential for industrial and medicinal applications, especially as an attractive biocatalyst for the production of oligosaccharides with special bioactivities. A novel alginate lyase, AlyH1, from the marine bacterium Vibrio furnissii H1, which has been newly isolated from rotten seaweed, was purified and characterized. The purified enzyme showed the specific activity of 2.40 U/mg. Its molecular mass was 35.8 kDa. The optimal temperature and pH were 40 °C and pH 7.5, respectively. AlyH1 maintained stability at neutral pH (7.0–8.0 and temperatures below 30 °C. Metal ions Na+, Mg2+, and K+ increased the activity of the enzyme. With sodium alginate as the substrate, the Km and Vmax values of AlyH1 were 2.28 mg/mL and 2.81 U/mg, respectively. AlyH1 exhibited activities towards both polyguluronate and polymannuronate, and preferentially degraded polyguluronate. Products prepared from sodium alginate by AlyH1 were displayed to be di-, tri-, and tetra-alginate oligosaccharides. A partial amino acid sequence (190 aa of AlyH1 analysis suggested that AlyH1 was an alginate lyase of polysaccharide lyase family 7. The sequence showed less than 77% identity to the reported alginate lyases. These data demonstrated that AlyH1 could be as a novel and potential candidate in application of alginate oligosaccharides production with low polymerization degrees.

Radioiodinated 4-iodo-L-meta-tyrosine, a system L selective artificial amino acid: molecular design and transport characterization in Chinese hamster ovary cells (CHO-K1 cells)

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Shikano, Naoto, E-mail: sikano@ipu.ac.j [Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, 4669-2 Ami, Ami-machi, Inashiki-gun, Ibaraki 300-0394 (Japan); Kotani, Takashi; Nakajima, Syuichi; Ogura, Masato; Nakazawa, Shinya [Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, 4669-2 Ami, Ami-machi, Inashiki-gun, Ibaraki 300-0394 (Japan); Sagara, Jun-ichi [Center for Humanities and Sciences, Ibaraki Prefectural University of Health Sciences, 4669-2 Ami, Ami-machi, Inashiki-gun, Ibaraki 300-0394 (Japan); Kobayashi, Masato [Division of Health Science, Graduate School of Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 9200-942 (Japan); Baba, Takeshi; Yamaguchi, Naoto [Center for Medical Science, Ibaraki Prefectural University of Health Sciences, 4669-2 Ami, Ami-machi, Inashiki-gun, Ibaraki 300-0394 (Japan); Kubota, Nobuo [Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, 4669-2 Ami, Ami-machi, Inashiki-gun, Ibaraki 300-0394 (Japan); Kawai, Keiichi [Division of Health Science, Graduate School of Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 9200-942 (Japan)

2010-11-15

Introduction: High expression of the system L amino acid transporter has been observed in clinically important tissues including tumors and the blood-brain barrier. We examined amino acid transport system L selectivity of {sup 14}C(U)-L-tyrosine ({sup 14}C-Tyr), {sup 125}I-4-iodo-L-meta-tyrosine (4-{sup 125}I-mTyr), {sup 125}I-6-iodo-L-meta-tyrosine (6-{sup 125}I-mTyr), {sup 125}I-3-iodo-{alpha}-methyl-L-tyrosine ({sup 125}I-IMT) and {sup 125}I-3-iodo-L-tyrosine (3-{sup 125}I-Tyr) using Chinese hamster ovary cells (CHO-K1). Methods: Cells in the exponential growth phase were incubated with 18.5 kBq of labeled amino acid in 2 mL of phosphate-buffered saline-based uptake solution and an uptake solution with/without Na{sup +} at 37{sup o}C or 4{sup o}C. We examined the effects of the following compounds (1.0 mM) on transport: 2-(methylamino)isobutyric acid (a specific inhibitor of system A, in Na{sup +}-containing uptake solution); 2-amino-bicyclo[2,2,1]heptane-2-carboxylic acid (a specific inhibitor of system L, in Na{sup +}-free uptake solution); sodium azide and 2,4-dinitrophenol (NaN{sub 3} and DNP, inhibitors of the generation of adenosine triphosphate); p-aminohippurate and tetraethylammonium (PAH and TEA, inhibitors of organic anion and cation transporters); and L- and D-isomers of natural amino acids. Results: {sup 14}C-Tyr exhibited affinity for systems L, A and ASC. 4-{sup 125}I-mTyr and 3-{sup 125}I-Tyr exhibited high specificity for system L, whereas 6-{sup 125}I-mTyr and {sup 125}I-IMT exhibited affinity for both systems L and ASC. Uptake of 4-{sup 125}I-mTyr was markedly reduced by incubation at 4 {sup o}C, and was not significantly inhibited by NaN{sub 3}, DNP, PAH or TEA. The inhibition profiles of the L- and D-isomers of natural amino acids indicated that system L mediates the transport of 4-{sup 125}I-mTyr. Conclusions: 4-{sup 125}I-mTyr exhibited the greatest system L specificity (93.46{+-}0.13%) of all of the tested amino acids.

Tyrosine 625 plays a key role and cooperates with tyrosine 630 in MPL W515L-induced signaling and myeloproliferative neoplasms

OpenAIRE

Yu, Chunjie; Yang, Qiong; Chen, Yuhong; Wang, Demin; Levine, Ross; Crispino, John; Wen, Qiang; Huang, Zan

2016-01-01

Background Myeloproliferative neoplasms (MPN) are a group of blood cancers that boost normal blood cell production in the bone marrow. Abnormal mutations in stem cells were found accompanying with the occurrence of MPN. It has been shown that MPL mutations (MPL W515L or MPL W515K) were involved in patients with MPN. Since tyrosine residues 625 and 630 mediate normal MPL signaling, whether them affect MPL W515L-induced myeloproliferative neoplasms (MPNs) is unknown. Results In this study, we f...

Toxicity of Phenol and Salt on the Phenol-Degrading Pseudomonas aeruginosa Bacterium

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Samaei

2016-08-01

Full Text Available Background Phenolic compounds, phenol and phenol derivatives are environmental contaminants in some industrial effluents. Entrance of such substances into the environment causes severe environmental pollution, especially pollution of water resources. Biological treatment is a method that uses the potential of microorganisms to clean up contaminated environments. Among microorganisms, bacteria play an important role in treating wastewater contaminated with phenol. Objectives This study aimed to examine the effects of Pseudomonas aeruginosa on degradation of phenol in wastewater contaminated with this pollutant. Methods In this method, the growth rate of P. aeruginosa bacteria was investigated using different concentrations of salt and phenol. This is an experimental study conducted as a pilot in a batch reactor with different concentrations of phenol (25, 50, 100, 150, 300 and 600 mg L-1 and salt (0%, 0.5%, 1%, 2.5% and 5% during 9, 12 and 15 hours. During three days, from 5 experimental and 3 control samples, 18 samples were taken a day forming a sample size of 54 samples for each phenol concentration. Given the number of phenol concentrations (n = 6, a total of 324 samples were analyzed using a spectrophotometer at a wavelength of 600 nm. Results The phenol concentration of 600 mg L-1 was toxic for P. aeruginosa. However, at a certain concentration, it acts as a carbon source for P. aeruginosa. During investigations, it was found that increasing the concentration of phenol increases the rate of bacteria growth. The highest bacteria growth rate occurred was at the salt concentration of zero and phenol concentration of 600 mg L-1. Conclusions The findings of the current study indicate that at high concentrations of salt, the growth of bacteria reduces so that it stops at a concentration of 50 mg L-1 (5%. Thus, the bacterium is halotolerant or halophilic. With an increase in phenol concentration, the growth rate increased. Phenol toxicity appears

Raman scattering tensors of tyrosine.

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Tsuboi, M; Ezaki, Y; Aida, M; Suzuki, M; Yimit, A; Ushizawa, K; Ueda, T

1998-01-01

Polarized Raman scattering measurements have been made of a single crystal of L-tyrosine by the use of a Raman microscope with the 488.0-nm exciting beam from an argon ion laser. The L-tyrosine crystal belongs to the space group P2(1)2(1)2(1) (orthorhombic), and Raman scattering intensities corresponding to the aa, bb, cc, ab and ac components of the crystal Raman tensor have been determined for each prominent Raman band. A similar set of measurements has been made of L-tyrosine-d4, in which four hydrogen atoms on the benzene ring are replaced by deuterium atoms. The effects of NH3-->ND3 and OH-->OD on the Raman spectrum have also been examined. In addition, depolarization ratios of some bands of L-tyrosine in aqueous solutions of pH 13 and pH 1 were examined. For comparison with these experimental results, on the other hand, ab initio molecular orbital calculations have been made of the normal modes of vibration and their associated polarizability oscillations of the L-tyrosine molecule. On the basis of these experimental data and by referring to the results of the calculations, discussions have been presented on the Raman tensors associated to some Raman bands, including those at 829 cm-1 (benzene ring breathing), 642 cm-1 (benzene ring deformation), and 432 cm-1 (C alpha-C beta-C gamma bending).

Not so monofunctional--a case of thermostable Thermobifida fusca catalase with peroxidase activity.

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Lončar, Nikola; Fraaije, Marco W

2015-03-01

Thermobifida fusca is a mesothermophilic organism known for its ability to degrade plant biomass and other organics, and it was demonstrated that it represents a rich resource of genes encoding for potent enzymes for biocatalysis. The thermostable catalase from T. fusca has been cloned and overexpressed in Escherichia coli with a yield of 400 mg/L. Heat treatment of disrupted cells at 60 °C for 1 h resulted in enzyme preparation of high purity; hence, no chromatography steps are needed for large-scale production. Except for catalyzing the dismutation of hydrogen peroxide, TfuCat was also found to catalyze oxidations of phenolic compounds. The catalase activity was comparable to other described catalases while peroxidase activity was quite remarkable with a k obs of nearly 1000 s(-1) for catechol. Site directed mutagenesis was used to alter the ratio of peroxidase/catalase activity. Resistance to inhibition by classic catalase inhibitors and an apparent melting temperature of 74 °C classifies this enzyme as a robust biocatalyst. As such, it could compete with other commercially available catalases while the relatively high peroxidase activity also offers new biocatalytic possibilities.

Molecular characterization of a Penicillium chrysogenum exo-rhamnogalacturonan lyase that is structurally distinct from other polysaccharide lyase family proteins.

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Iwai, Marin; Kawakami, Takuya; Ikemoto, Takeshi; Fujiwara, Daisuke; Takenaka, Shigeo; Nakazawa, Masami; Ueda, Mitsuhiro; Sakamoto, Tatsuji

2015-10-01

We previously described an endo-acting rhamnogalacturonan (RG) lyase, termed PcRGL4A, of Penicillium chrysogenum 31B. Here, we describe a second RG lyase, called PcRGLX. We determined the cDNA sequence of the Pcrglx gene, which encodes PcRGLX. Based on analyses using a BLAST search and a conserved domain search, PcRGLX was found to be structurally distinct from known RG lyases and might belong to a new polysaccharide lyase family together with uncharacterized fungal proteins of Nectria haematococca, Aspergillus oryzae, and Fusarium oxysporum. The Pcrglx cDNA gene product (rPcRGLX) expressed in Escherichia coli demonstrated specific activity against RG but not against homogalacturonan. Divalent cations were not essential for the enzymatic activity of rPcRGLX. rPcRGLX mainly released unsaturated galacturonosyl rhamnose (ΔGR) from RG backbones used as the substrate from the initial stage of the reaction, indicating that the enzyme can be classified as an exo-acting RG lyase (EC 4.2.2.24). This is the first report of an RG lyase with this mode of action in Eukaryota. rPcRGLX acted synergistically with PcRGL4A to degrade soybean RG and released ΔGR. This ΔGR was partially decorated with galactose (Gal) residues, indicating that rPcRGLX preferred oligomeric RGs to polymeric RGs, that the enzyme did not require Gal decoration of RG backbones for degradation, and that the enzyme bypassed the Gal side chains of RG backbones. These characteristics of rPcRGLX might be useful in the determination of complex structures of pectins.

Identification and optimization of tyrosine hydroxylase activity in Mucuna pruriens DC. var. utilis.

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Luthra, Pratibha Mehta; Singh, Satendra

2010-05-01

Tyrosine hydroxylase, an iron containing tetrahydrobiopterin dependent monooxygenase (tyrosine 3-monooxygenase; EC 1.14.16.2), catalyzes the rate-limiting step in which L: -dopa is formed from the substrate L-tyrosine. L-Dopa concentration and activity of L-tyrosine hydroxylase enzyme were measured in roots, stem, leaves, pods, and immature seeds of Mucuna pruriens. Immature seeds contained maximum L-dopa content and mature leaves possessed maximum catalytic activity of tyrosine hydroxylase. Tyrosine hydroxylase from leaf homogenate was characterized as a 55 kDa protein by SDS-PAGE and Western-blot analysis with monoclonal mouse IgG2a tyrosine hydroxylase antibody. The conditions for maximum tyrosine hydroxylase activity from the leaf extract were optimized with respect to temperature, pH, cofactor 6-MPH(4), and divalent metal ions. The tyrosine hydroxylase from leaf extract possessed a K (m) value of 808.63 microM for L-tyrosine at 37 degrees C and pH 6.0. The activity of the enzyme was slightly inhibited at 2,000 microM L-tyrosine. Higher concentrations of the cofactor 6-MPH(4), however, completely inhibited the synthesis of L-dopa. Tyrosine hydroxylase converted specific monophenols such as L-tyrosine (808.63 microM) and tyramine (K (m) 1.1 mM) to diphenols L-dopa and dopamine, respectively. Fe(II) activated the enzyme while higher concentration of other divalent metals reduced its activity. For the first time, tyrosine hydroxylase from M. pruriens is being reported in this study.

Preliminary structural investigations of the Eut-L shell protein of the ethanolamine ammonia-lyase metabolosome of Escherichia coli

International Nuclear Information System (INIS)

Nikolakakis, Kiel; Ohtaki, Akashi; Newton, Keith; Chworos, Arkadiusz; Sagermann, Martin

2009-01-01

Preliminary X-ray analysis of crystals of the bacterial microcompartment shell protein Eut-L from Escherichia coli is reported. The ethanolamine ammonia-lyase microcompartment is composed of five different shell proteins that have been proposed to assemble into symmetrically shaped polyhedral particles of varying sizes. Here, preliminary X-ray analysis of crystals of the bacterial microcompartment shell protein Eut-L from Escherichia coli is reported. Cloning, overexpression and purification resulted in highly pure protein that crystallized readily under many different conditions. In all cases the protein forms thin hexagonal plate-shaped crystals belonging to space group P3 that are of unusually high stability against different solvent conditions. The crystals diffracted to a resolution of 2.0 Å using synchrotron radiation but proved to be radiation-sensitive. Preparations of heavy-atom-derivatized crystals for use in determining the three-dimensional structure are under way

Changes in element accumulation, phenolic metabolism, and antioxidative enzyme activities in the red-skin roots of Panax ginseng.

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Zhou, Ying; Yang, Zhenming; Gao, Lingling; Liu, Wen; Liu, Rongkun; Zhao, Junting; You, Jiangfeng

2017-07-01

Red-skin root disease has seriously decreased the quality and production of Panax ginseng (ginseng). To explore the disease's origin, comparative analysis was performed in different parts of the plant, particularly the epidermis, cortex, and/or fibrous roots of 5-yr-old healthy and diseased red-skin ginseng. The inorganic element composition, phenolic compound concentration, reactive oxidation system, antioxidant concentrations such as ascorbate and glutathione, activities of enzymes related to phenolic metabolism and oxidation, and antioxidative system particularly the ascorbate-glutathione cycle were examined using conventional methods. Aluminum (Al), iron (Fe), magnesium, and phosphorus were increased, whereas manganese was unchanged and calcium was decreased in the epidermis and fibrous root of red-skin ginseng, which also contained higher levels of phenolic compounds, higher activities of the phenolic compound-synthesizing enzyme phenylalanine ammonia-lyase and the phenolic compound oxidation-related enzymes guaiacol peroxidase and polyphenoloxidase. As the substrate of guaiacol peroxidase, higher levels of H 2 O 2 and correspondingly higher activities of superoxide dismutase and catalase were found in red-skin ginseng. Increased levels of ascorbate and glutathione; increased activities of l-galactose 1-dehydrogenase, ascorbate peroxidase, ascorbic acid oxidase, and glutathione reductase; and lower activities of dehydroascorbate reductase, monodehydroascorbate reductase, and glutathione peroxidase were found in red-skin ginseng. Glutathione- S -transferase activity remained constant. Hence, higher element accumulation, particularly Al and Fe, activated multiple enzymes related to accumulation of phenolic compounds and their oxidation. This might contribute to red-skin symptoms in ginseng. It is proposed that antioxidant and antioxidative enzymes, especially those involved in ascorbate-glutathione cycles, are activated to protect against phenolic compound

High-Level Expression of a Thermally Stable Alginate Lyase Using Pichia pastoris, Characterization and Application in Producing Brown Alginate Oligosaccharide

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Haifeng Li

2018-05-01

Full Text Available An alginate lyase encoding gene sagl from Flavobacterium sp. H63 was codon optimized and recombinantly expressed at high level in P.pastoris through high cell-density fermentation. The highest yield of recombinant enzyme of sagl (rSAGL in yeast culture supernatant reached 226.4 μg/mL (915.5 U/mL. This was the highest yield record of recombinant expression of alginate lyase so far. The rSAGL was confirmed as a partially glycosylated protein through EndoH digestion. The optimal reaction temperature and pH of this enzyme were 45 °C and 7.5; 80 mM K+ ions could improve the catalytic activity of the enzyme by 244% at most. rSAGL was a thermal stable enzyme with T5015 of 57–58 °C and T5030 of 53–54 °C. Its thermal stability was better than any known alginate lyase. In 100 mM phosphate buffer of pH 6.0, rSAGL could retain 98.8% of the initial activity after incubation at 50 °C for 2 h. Furthermore, it could retain 61.6% of the initial activity after 48 h. The specific activity of the purified rSAGL produced by P. pastoris attained 4044 U/mg protein, which was the second highest record of alginate lyase so far. When the crude enzyme of the rSAGL was directly used in transformation of sodium alginate with 40 g/L, 97.2% of the substrate was transformed to di, tri, tetra brown alginate oligosaccharide after 32 h of incubation at 50 °C, and the final concentration of reducing sugar in mixture reached 9.51 g/L. This is the first report of high-level expression of thermally stable alginate lyase using P. pastoris system.

Enzyme-assisted extraction enhancing the phenolic release from cauliflower (Brassica oleracea L. var. botrytis) outer leaves.

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Huynh, Nguyen Thai; Smagghe, Guy; Gonzales, Gerard Bryan; Van Camp, John; Raes, Katleen

2014-07-30

Phenolic compounds are highly present in byproducts from the cauliflower (Brassica oleracea L. var. botrytis) harvest and are thus a valuable source for valorization toward phenolic-rich extracts. In this study, we aimed to optimize and characterize the release of individual phenolic compounds from outer leaves of cauliflower, using two commercially available polysaccharide-degrading enzymes, Viscozyme L and Rapidase. As major results, the optimal conditions for the enzyme treatment were: enzyme/substrate ratio of 0.2% for Viscozyme L and 0.5% for Rapidase, temperature 35 °C, and pH 4.0. Using a UPLC-HD-TOF-MS setup, the main phenolic compounds in the extracts were identified as kaempferol glycosides and their combinations with different hydroxycinnamic acids. The most abundant components were kaempferol-3-feruloyldiglucoside and kaempferol-3-glucoside (respectively, 37.8 and 58.4 mg rutin equiv/100 g dry weight). Incubation of the cauliflower outer leaves with the enzyme mixtures resulted in a significantly higher extraction yield of kaempferol-glucosides as compared to the control treatment.

Cytoplasmic expression of a thermostable invertase from Thermotoga maritima in Lactococcus lactis.

Science.gov (United States)

Pek, Han Bin; Lim, Pei Yu; Liu, Chengcheng; Lee, Dong-Yup; Bi, Xuezhi; Wong, Fong Tian; Ow, Dave Siak-Wei

2017-05-01

To evaluate the secretory and cytoplasmic expression of a thermostable Thermogata maritima invertase in Lactococcus lactis. The thermostable invertase from T. maritima was cloned with and without the USP45 secretory peptide into the pNZ8148 vector for nisin-inducible expression in L. lactis. The introduction of an USP45 secretion peptide at the N-terminal of the enzyme led to a loss of protein solubility. Computational homology modeling and hydrophobicity studies indicated that the USP45 peptide exposes a stretch of hydrophobic amino acids on the protein surface resulting in lower solubility. Removal of the USP45 secretion peptide allowed a soluble and functional invertase to be expressed intracellularly in L. lactis. Immobilized metal affinity chromatography purification of the cell lysate with nickel-NTA gave a single protein band on SDS-PAGE, while E. coli-expressed invertase consistently co-purified with an additional band. The yields of the purified invertase from E. coli and L. lactis were 14.1 and 6.3 mg/l respectively. Invertase can be expressed in L. lactis and purified in a functional form. L. lactis is a suitable host for the production of food-grade invertase for use in the food and biotechnology industries.

Tyrosine 625 plays a key role and cooperates with tyrosine 630 in MPL W515L-induced signaling and myeloproliferative neoplasms.

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Yu, Chunjie; Yang, Qiong; Chen, Yuhong; Wang, Demin; Levine, Ross; Crispino, John; Wen, Qiang; Huang, Zan

2016-01-01

Myeloproliferative neoplasms (MPN) are a group of blood cancers that boost normal blood cell production in the bone marrow. Abnormal mutations in stem cells were found accompanying with the occurrence of MPN. It has been shown that MPL mutations (MPL W515L or MPL W515K) were involved in patients with MPN. Since tyrosine residues 625 and 630 mediate normal MPL signaling, whether them affect MPL W515L-induced myeloproliferative neoplasms (MPNs) is unknown. In this study, we further tested their functions in MPL W515L-induced myeloproliferative neoplasms (MPNs) by substituting either or both of them with phenylalanine in MPL W515L (termed as MPL515/625, MPL515/630 and MPL515/625/630, respectively). In vitro, MPL515/630 but not MPL515/625 or MPL515/625/630 retained the ability to induce TPO-independent proliferation and increase colony-forming unit megakaryocytes (CFU-Mk). Accordingly, differential activation of the downstream signaling by four mutants was observed and constitutively active STAT5 or AKT instead of STAT3 partially compensated MPL515/625/630 function. Further support this, STAT5-deficiency impaired MPL W515L-induced CFU-Mk expansion. In vivo, MPL515/630 but not MPL515/625 or MPL515/625/630 induced typical features of MPNs with high WBC and platelet counts, splenomegaly, hepatomegaly and hypercellularity in the bone marrow. Surprisingly, MPL515/625 also caused hypercellularity of bone marrow and splenomegaly without any other significant features. We also observed differential effects of the four mutants on progenitors, myeloid cells and megakaryocytes. Our studies have revealed distinct features of tyrosine sites 625 and 630 in mediating MPL W515L-induced megakaryocyte hyperproliferation and MPNs. Our study also suggests that MPL cytosolic phosphorylated Y625 and flanking amino acids could become targets for pharmacologic inhibition in MPNs.

Phenolic profiles and antioxidant properties of young wines made from Yan73 (Vitis vinifera L.) and Cabernet Sauvignon (Vitis vinifera L.) grapes treated by 24-epibrassinolide.

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Xu, Fan; Luan, Li-Ying; Zhang, Zhen-Wen; Huo, Shan-Shan; Gao, Xiang; Fang, Yu-Lin; Xi, Zhu-Mei

2014-07-14

The grape berries of two varieties, Yan73 (Vitis vinifera L.) and Cabernet Sauvignon (CS) (Vitis vinifera L.) were treated with 0.40 mg/L 24-epibrassinolide (EBR), 1.00 mg/L brassinazole (Brz), and deionized water (control), at the veraison period. The EBR treatment significantly increased total phenolic content (TPC), total tannin content (TTC) and total anthocyanin content (TAC) of Yan73 and CS wines, whereas Brz treatment decreased TPC, total flavonoid content (TFC), TAC in the two wines. Moreover, the content of most of the phenolic compounds identified by HPLC-DAD/ESI-MS in EBR-treated wines was significantly higher than that in control. The antioxidant capacities, which determined using DPPH, ABTS and HRSA methods, of the wines were increased by EBR treatment as well. There was a good correlation between the antioxidant capacity and phenolic content. The results demonstrated that EBR could enhance the phenolic compounds and antioxidant capacity of Yan73 and CS wines, but the effects may vary by different cultivars.

The impact of making vaccines thermostable in Niger's vaccine supply chain.

Science.gov (United States)

Lee, Bruce Y; Cakouros, Brigid E; Assi, Tina-Marie; Connor, Diana L; Welling, Joel; Kone, Souleymane; Djibo, Ali; Wateska, Angela R; Pierre, Lionel; Brown, Shawn T

2012-08-17

Determine the effects on the vaccine cold chain of making different types of World Health Organization (WHO) Expanded Program on Immunizations (EPI) vaccines thermostable. Utilizing a detailed computational, discrete-event simulation model of the Niger vaccine supply chain, we simulated the impact of making different combinations of the six current EPI vaccines thermostable. Making any EPI vaccine thermostable relieved existing supply chain bottlenecks (especially at the lowest levels), increased vaccine availability of all EPI vaccines, and decreased cold storage and transport capacity utilization. By far, the most substantial impact came from making the pentavalent vaccine thermostable, increasing its own vaccine availability from 87% to 97% and the vaccine availabilities of all other remaining non-thermostable EPI vaccines to over 93%. By contrast, making each of the other vaccines thermostable had considerably less effect on the remaining vaccines, failing to increase the vaccine availabilities of other vaccines to more than 89%. Making tetanus toxoid vaccine along with the pentavalent thermostable further increased the vaccine availability of all EPI vaccines by at least 1-2%. Our study shows the potential benefits of making any of Niger's EPI vaccines thermostable and therefore supports further development of thermostable vaccines. Eliminating the need for refrigerators and freezers should not necessarily be the only benefit and goal of vaccine thermostability. Rather, making even a single vaccine (or some subset of the vaccines) thermostable could free up significant cold storage space for other vaccines, and thereby help alleviate supply chain bottlenecks that occur throughout the world. Copyright © 2012 Elsevier Ltd. All rights reserved.

Development of a microchip-pulsed electrochemical method for rapid determination of L-DOPA and tyrosine in Mucuna pruriens.

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Li, Xinchun; Chen, Zuanguang; Yang, Fan; Pan, Jianbin; Li, Yinbao

2013-05-01

L-3,4-dihydroxyphenylalanine (L-DOPA) is a well-recognized therapeutic compound to Parkinson's disease. Tyrosine is a precursor for the biosynthesis of L-DOPA, both of which are widely found in traditional medicinal material, Mucuna pruriens. In this paper, we described a validated novel analytical method based on microchip capillary electrophoresis with pulsed electrochemical detection for the simultaneous measurement of L-DOPA and tyrosine in M. pruriens. This protocol adopted end-channel amperometric detection using platinum disk electrode on a homemade glass/polydimethylsiloxane electrophoresis microchip. The background buffer consisted of 10 mM borate (pH 9.5) and 0.02 mM cetyltrimethylammonium bromide, which can produce an effective resolution for the two analytes. In the optimal condition, sufficient electrophoretic separation and sensitive detection for the target analytes can be realized within 60 s. Both tyrosine and L-DOPA yielded linear response in the concentration range of 5.0-400 μM (R(2) > 0.99), and the LOD were 0.79 and 1.1 μM, respectively. The accuracy and precision of the established method were favorable. The present method shows several merits such as facile apparatus, high speed, low cost and minimal pollution, and provides a means for the pharmacologically active ingredients assay in M. pruriens. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of 14C-labelled α-methyl tyrosine

International Nuclear Information System (INIS)

Rajagopal, S.; Venkatachalam, T.K.; Conway, T.; Diksic, M.

1992-01-01

A new route for the preparation of radioactively labelled α-methyl L-tyrosine is described. The labelling at the α position has been successfully achieved with 14 C-, 11 C- (very preliminary, unpublished), and 3 H-labelled methyl iodide. A detailed report on 14 C-labelling at the α position and the hydrolysis of 4-methoxy α-methyl phenylalanine is presented. The alkylation proceeds via the methylation of the carbanion of N-benzylidene 4-methoxy phenylalanine methyl ester 2. Hydrolysis of 4-O methyl tyrosine to tyrosine by HBr and HI were analysed and used in the optimization of the hydrolysis conditions of 4. Enantiomeric purity of the isolated L-isomer has been found to be 99% as judged by HPLC. Pseudo first-order rate constant for the hydrolysis of 14 C-labelled α-methyl 4-methoxy phenyl alanine methyl ester was determined. Preliminary findings of the 3 H- and 11 C-radiolabelled α-methyl tyrosine (methyl labelled) are also mentioned. For the first time it was shown that α-methyl D,L-tyrosine can be separated into enantiomerically pure α-methyl D- and L-tyrosine using a CHIRALPAK WH column. (author)

In Silico Characterization of Pectate Lyase Protein Sequences from Different Source Organisms

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Amit Kumar Dubey

2010-01-01

Full Text Available A total of 121 protein sequences of pectate lyases were subjected to homology search, multiple sequence alignment, phylogenetic tree construction, and motif analysis. The phylogenetic tree constructed revealed different clusters based on different source organisms representing bacterial, fungal, plant, and nematode pectate lyases. The multiple accessions of bacterial, fungal, nematode, and plant pectate lyase protein sequences were placed closely revealing a sequence level similarity. The multiple sequence alignment of these pectate lyase protein sequences from different source organisms showed conserved regions at different stretches with maximum homology from amino acid residues 439–467, 715–816, and 829–910 which could be used for designing degenerate primers or probes specific for pectate lyases. The motif analysis revealed a conserved Pec_Lyase_C domain uniformly observed in all pectate lyases irrespective of variable sources suggesting its possible role in structural and enzymatic functions.

Crystallization and preliminary X-ray analysis of an exotype alginate lyase Atu3025 from Agrobacterium tumefaciens strain C58, a member of polysaccharide lyase family 15

International Nuclear Information System (INIS)

Ochiai, Akihito; Yamasaki, Masayuki; Mikami, Bunzo; Hashimoto, Wataru; Murata, Kousaku

2006-01-01

The crystallization and preliminary X-ray characterization of a family PL-15 exotype alginate lyase are presented. Almost all alginate lyases depolymerize alginate in an endolytical fashion via a β-elimination reaction. The alginate lyase Atu3025 from Agrobacterium tumefaciens strain C58, consisting of 776 amino-acid residues, is a novel exotype alginate lyase classified into polysaccharide lyase family 15. The enzyme was crystallized at 293 K by sitting-drop vapour diffusion with polyethylene glycol 4000 as a precipitant. Preliminary X-ray analysis showed that the Atu3025 crystal belonged to space group P2 1 and diffracted to 2.8 Å resolution, with unit-cell parameters a = 107.7, b = 108.3, c = 149.5 Å, β = 91.5°

Structural characterization of the thermostable Bradyrhizobium japonicumD-sorbitol dehydrogenase.

Science.gov (United States)

Fredslund, Folmer; Otten, Harm; Gemperlein, Sabrina; Poulsen, Jens Christian N; Carius, Yvonne; Kohring, Gert Wieland; Lo Leggio, Leila

2016-11-01

Bradyrhizobium japonicum sorbitol dehydrogenase is NADH-dependent and is active at elevated temperatures. The best substrate is D-glucitol (a synonym for D-sorbitol), although L-glucitol is also accepted, giving it particular potential in industrial applications. Crystallization led to a hexagonal crystal form, with crystals diffracting to 2.9 Å resolution. In attempts to phase the data, a molecular-replacement solution based upon PDB entry 4nbu (33% identical in sequence to the target) was found. The solution contained one molecule in the asymmetric unit, but a tetramer similar to that found in other short-chain dehydrogenases, including the search model, could be reconstructed by applying crystallographic symmetry operations. The active site contains electron density consistent with D-glucitol and phosphate, but there was not clear evidence for the binding of NADH. In a search for the features that determine the thermostability of the enzyme, the T m for the orthologue from Rhodobacter sphaeroides, for which the structure was already known, was also determined, and this enzyme proved to be considerably less thermostable. A continuous β-sheet is formed between two monomers in the tetramer of the B. japonicum enzyme, a feature not generally shared by short-chain dehydrogenases, and which may contribute to thermostability, as may an increased Pro/Gly ratio.

Total phenolic compounds, antioxidant potential and α-glucosidase inhibition by Tunisian Euphorbia paralias L.

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Malek Besbes Hlila

2016-08-01

Full Text Available Objective: To examine the potential antioxidant and anti-α-glucosidase inhibitory activities of Tunisian Euphorbia paralias L. leaves and stems extracts and their composition of total polyphenol and flavonoids. Methods: The different samples were tested for their antiradical activities by using 2, 2’- azinobis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS and 1,1-diphenyl-2-picrylhydrazyl (DPPH assays. In α-glucosidase activity, α-glucosidase (0.3 IU/mL and substrate, 2500 µmol/ L p-nitrophenyl α-D-glucopyranoside were used; absorbance was registered at 405 nm. Results: The leaves acetonic extract exhibited the strongest α-glucosidase inhibition [IC50 = (0.0035 ± 0.001 µg/mL], which was 20-fold more active than the standard product (acarbose [IC50 = (0.07 ± 0.01 µg/mL]. Acetonic extract of the leaves exhibited the highest quantity of total phenolic [(95.54 ± 0.04 µg gallic acid equivalent/mg] and flavonoid [(55.16 ± 0.25 µg quercetin equivalent/mg]. The obtained findings presented also that this extract was detected with best antioxidant capacity [IC50 = (0.015 ± 0.01 µg/mL] against DPPH and a value of IC50 equal to (0.02 ± 0.01 µg/mL against ABTS. Positive relationship between polyphenolic content of the tested Euphorbia paralias L. leaves and stems extracts and its antioxidant activity (DPPH and ABTS was detected. Elevated positive linear correlation was got between ABTS and total phenolic (R2 = 0.751. Conclusions: The findings clearly demonstrate that the use of a polar solvent enables extraction of significant quantities of phenol compounds and flavonoids.

Bilirubin oxidase-like proteins from Podospora anserina: promising thermostable enzymes for application in transformation of plant biomass.

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Xie, Ning; Ruprich-Robert, Gwenaël; Silar, Philippe; Chapeland-Leclerc, Florence

2015-03-01

Plant biomass degradation by fungi is a critical step for production of biofuels, and laccases are common ligninolytic enzymes envisioned for ligninolysis. Bilirubin oxidases (BODs)-like are related to laccases, but their roles during lignocellulose degradation have not yet been fully investigated. The two BODs of the ascomycete fungus Podospora anserina were characterized by targeted gene deletions. Enzymatic assay revealed that the bod1(Δ) and bod2(Δ) mutants lost partly a thermostable laccase activity. A triple mutant inactivated for bod1, bod2 and mco, a previously investigated multicopper oxidase gene distantly related to laccases, had no thermostable laccase activity. The pattern of fruiting body production in the bod1(Δ) bod2(Δ) double mutant was changed. The bod1(Δ) and bod2(Δ) mutants were reduced in their ability to grow on ligneous and cellulosic materials. Furthermore, bod1(Δ) and bod2(Δ) mutants were defective towards resistance to phenolic substrates and H2 O2 , which may also impact lignocellulose breakdown. Double and triple mutants were more affected than single mutants, evidencing redundancy of function among BODs and mco. Overall, the data show that bod1, bod2 and mco code for non-canonical thermostable laccases that participate in the degradation of lignocellulose. Thanks to their thermal stability, these enzymes may be more promising candidate for biotechnological application than canonical laccases. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

Phenolic profile of Centaurea aegyptiaca L. growing in Egypt and its ...

African Journals Online (AJOL)

Background: Centaurea aegyptiaca L (Asteraceae), is one of the most attractive plants growing wildly in Sinai, and is not well investigated for its phytochemical constituents. This study represents the first in-depth characterization of the phenolic profile of the aerial parts of C. aegyptiaca methanolic extract utilizing liquid ...

Thermostable L-arabinose isomerase from Bacillus stearothermophilus IAM 11001 for D-tagatose production: gene cloning, purification and characterisation.

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Cheng, Lifang; Mu, Wanmeng; Jiang, Bo

2010-06-01

D-Tagatose, as one of the rare sugars, has been found to be a natural and safe low-calorie sweetener in food products and is classified as a GRAS substance. L-Arabinose isomerase (L-AI, EC 5.3.1.4), catalysing the isomerisations of L-arabinose and D-galactose to L-ribulose and D-tagatose respectively, is considered to be the most promising enzyme for the production of D-tagatose. The araA gene encoding an L-AI from Bacillus stearothermophilus IAM 11001 was cloned, sequenced and overexpressed in Escherichia coli. The gene is composed of 1491 bp nucleotides and codes for a protein of 496 amino acid residues. The recombinant L-AI was purified to electrophoretical homogeneity by affinity chromatography. The purified enzyme was optimally active at 65 degrees C and pH 7.5 and had an absolute requirement for the divalent metal ion Mn(2+) for both catalytic activity and thermostability. The enzyme was relatively active and stable at acidic pH of 6. The bioconversion yield of D-galactose to D-tagatose by the purified L-AI after 12 h at 65 degrees C reached 36%. The purified L-AI from B. stearothermophilus IAM 11001 was characterised and shown to be a good candidate for potential application in D-tagatose production. Copyright (c) 2010 Society of Chemical Industry.

Phenolic Profiles and Antioxidant Properties of Young Wines Made from Yan73 (Vitis vinifera L. and Cabernet Sauvignon (Vitis vinifera L. Grapes Treated by 24-Epibrassinolide

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Fan Xu

2014-07-01

Full Text Available The grape berries of two varieties, Yan73 (Vitis vinifera L. and Cabernet Sauvignon (CS (Vitis vinifera L. were treated with 0.40 mg/L 24-epibrassinolide (EBR, 1.00 mg/L brassinazole (Brz, and deionized water (control, at the veraison period. The EBR treatment significantly increased total phenolic content (TPC, total tannin content (TTC and total anthocyanin content (TAC of Yan73 and CS wines, whereas Brz treatment decreased TPC, total flavonoid content (TFC, TAC in the two wines. Moreover, the content of most of the phenolic compounds identified by HPLC-DAD/ESI-MS in EBR-treated wines was significantly higher than that in control. The antioxidant capacities, which determined using DPPH, ABTS and HRSA methods, of the wines were increased by EBR treatment as well. There was a good correlation between the antioxidant capacity and phenolic content. The results demonstrated that EBR could enhance the phenolic compounds and antioxidant capacity of Yan73 and CS wines, but the effects may vary by different cultivars.

Determination of total phenolic content and antioxidant activitity of methanol extract of Maranta arundinacea L fresh leaf and tuber

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Kusbandari, A.; Susanti, H.

2017-11-01

Maranta arundinacea L is one of herbaceous plants in Indonesia which have flavonoid content. Flavonoids has antioxidants activity by inhibition of free radical oxidation reactions. The study aims were to determination total phenolic content and antioxidant activity of methanol extract of fresh leaf and tuber of M. arundinacea L by UV-Vis spectrophotometer. The methanol extracts were obtained with maceration and remaseration method of fresh leaves and tubers. The total phenolic content was assayed with visible spectrophotometric using Folin Ciocalteau reagent. The antioxidant activity was assayed with 1,1-diphenyl-2-picrilhidrazil (DPPH) compared to gallic acid. The results showed that methanol extract of tuber and fresh leaf of M. arundinacea L contained phenolic compound with total phenolic content (TPC) in fresh tuber of 3.881±0.064 (% GAE) and fresh leaf is 6.518±0.163 (% b/b GAE). IC50 value from fresh tuber is 1.780±0.0005 μg/mL and IC50 fresh leaf values of 0.274±0.0004 μg/mL while the standard gallic acid is IC50 of 0.640±0.0002 μg/mL.

Design and Testing of a Thermostable Platform for Multimerization of Single Domain Antibodies

Science.gov (United States)

2012-08-01

H.J. Properties , production, and applications of camelid single domain antibody fragments. Appl. Microbiol. Biot. 2007, 77, 13‒22. 2. Goldman...Conway, J.; Sherwood, L.J.; Fech, M.; Vo, B.; Liu, J.L.; Hayhurst, A. Thermostable llama single domain antibodies for detection of Botulinum A...antiparallel coiled-coil inserted. J. Mol. Bio. 2001, 306, 25‒35. 9. Liu, J.L.; Anderson, G.P.; Goldman, E.R. Isolation of anti- toxin single domain

Improvement in the thermostability of chitosanase from Bacillus ehimensis by introducing artificial disulfide bonds.

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Sheng, Jun; Ji, Xiaofeng; Zheng, Yuan; Wang, Zhipeng; Sun, Mi

2016-10-01

To determine the effects of artificial disulfide bridges on the thermostability and catalytic efficiency of chitosanase EAG1. Five artificial disulfide bridges were designed based on the structural information derived from the three-dimensional (3-D) model of chitosanase EAG1. Two beneficial mutants (G113C/D116C, A207C-L286C) were located in the flexible surface loop region, whereas the similar substitutions introduced in α-helices regions had a negligible effect. Mut5, the most active mutant, had a longer half-life at 50 °C (from 10.5 to 69.3 min) and a 200 % higher catalytic efficiency (K cat/K m) than that of the original EAG1. The contribution of disulfide bridges to enzyme thermostability is mainly dependent on its location within the polypeptide chain. Strategical placement of a disulfide bridge in flexible regions provides a rigid support and creation of a protected microenvironment, which is effective in improving enzyme's thermostability and catalytic efficiency.

Thermostable enzymes as biocatalysts in the biofuel industry.

Science.gov (United States)

Yeoman, Carl J; Han, Yejun; Dodd, Dylan; Schroeder, Charles M; Mackie, Roderick I; Cann, Isaac K O

2010-01-01

Lignocellulose is the most abundant carbohydrate source in nature and represents an ideal renewable energy source. Thermostable enzymes that hydrolyze lignocellulose to its component sugars have significant advantages for improving the conversion rate of biomass over their mesophilic counterparts. We review here the recent literature on the development and use of thermostable enzymes for the depolymerization of lignocellulosic feedstocks for biofuel production. Furthermore, we discuss the protein structure, mechanisms of thermostability, and specific strategies that can be used to improve the thermal stability of lignocellulosic biocatalysts. Copyright 2010 Elsevier Inc. All rights reserved.

Genetically engineering Synechocystis sp. Pasteur Culture Collection 6803 for the sustainable production of the plant secondary metabolite p-coumaric acid.

Science.gov (United States)

Xue, Yong; Zhang, Yan; Cheng, Dan; Daddy, Soumana; He, Qingfang

2014-07-01

p-Coumaric acid is the precursor of phenylpropanoids, which are plant secondary metabolites that are beneficial to human health. Tyrosine ammonia lyase catalyzes the production of p-coumaric acid from tyrosine. Because of their photosynthetic ability and biosynthetic versatility, cyanobacteria are promising candidates for the production of certain plant metabolites, including phenylpropanoids. Here, we produced p-coumaric acid in a strain of transgenic cyanobacterium Synechocystis sp. Pasteur Culture Collection 6803 (hereafter Synechocystis 6803). Whereas a strain of Synechocystis 6803 genetically engineered to express sam8, a tyrosine ammonia lyase gene from the actinomycete Saccharothrix espanaensis, accumulated little or no p-coumaric acid, a strain that both expressed sam8 and lacked slr1573, a native hypothetical gene shown here to encode a laccase that oxidizes polyphenols, produced ∼82.6 mg/L p-coumaric acid, which was readily purified from the growth medium.

The Impact of Making Vaccines Thermostable in Niger’s Vaccine Supply Chain

Science.gov (United States)

Lee, Bruce Y.; Cakouros, Brigid E.; Assi, Tina-Marie; Connor, Diana L.; Welling, Joel; Kone, Souleymane; Djibo, Ali; Wateska, Angela R.; Pierre, Lionel; Brown, Shawn T.

2012-01-01

Objective Determine the effects on the vaccine cold chain of making different types of World Health Organization (WHO) Expanded Program on Immunizations (EPI) vaccines thermostable. Methods Utilizing a detailed computational, discrete-event simulation model of the Niger vaccine supply chain, we simulated the impact of making different combinations of the six current EPI vaccines thermostable. Findings Making any EPI vaccine thermostable relieved existing supply chain bottlenecks (especially at the lowest levels), increased vaccine availability of all EPI vaccines, and decreased cold storage and transport capacity utilization. By far, the most substantial impact came from making the pentavalent vaccine thermostable, increasing its own vaccine availability from 87% to 97% and the vaccine availabilities of all other remaining non-thermostable EPI vaccines to over 93%. By contrast, making each of the other vaccines thermostable had considerably less effect on the remaining vaccines, failing to increase the vaccine availabilities of other vaccines to more than 89%. Making tetanus toxoid vaccine along with the pentavalent thermostable further increased the vaccine availability of all EPI vaccines by at least 1–2%. Conclusion Our study shows the potential benefits of making any of Niger’s EPI vaccines thermostable and therefore supports further development of thermostable vaccines. Eliminating the need for refrigerators and freezers should not necessarily be the only benefit and goal of vaccine thermostability. Rather, making even a single vaccine (or some subset of the vaccines) thermostable could free up significant cold storage space for other vaccines, and thereby help alleviate supply chain bottlenecks that occur throughout the world. PMID:22789507

Cloning and expression of isocitrate lyase from human round worm Strongyloides stercoralis

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Siddiqui A.A.

2000-09-01

Full Text Available A full length cDNA (1463 bp encoding isocitrate lyase (EC 4.1.3.1 of Strongyloides stercoralis is described. The nucleotide sequence of this insert identified a cDNA coding for the isocitrate lyase. The conceptually translated amino acid sequence of the open reading frame for S. stercoralis isocitrate lyase encodes a 450 amino acid residue protein with an apparent molecular weight of 50 kDa and a predicted pl of 6.39. The sequence is 69 % A/T, reflecting a characteristic A/T codon bias of S. stercoralis. The amino acid sequence of S. stercoralis isocitrate lyase is compared with bifunctional glyoxylate cycle protein of Caenorhabditis elegans and isocitrate lyases from Chlamydomonas reinhardtii and Myxococcus xanthus. The full length cDNA of S. stercoralis was expressed in pRSET vector and bacteriophage T7 promoter based expression system. S. stercoralis lyase recombinant protein, purified via immobilized metal affinity chromatography, showed a molecular mass of 50 kDa on polyacrylamide gels. The role of isocitrate lyase in the glyoxylate cycle and energy metabolism of S. stercoralis is also discussed.

Pharmacologic inhibition of L-tyrosine degradation ameliorates cerebral dopamine deficiency in murine phenylketonuria (PKU)

Science.gov (United States)

Harding, Cary O.; Winn, Shelley R.; Gibson, K. Michael; Arning, Erland; Bottiglieri, Teodoro; Grompe, Markus

2014-01-01

Summary Monoamine neurotransmitter deficiency has been implicated in the etiology of neuropsychiatric symptoms associated with chronic hyperphenylalaninemia in phenylketonuria (PKU). Two proposed explanations for neurotransmitter deficiency in PKU include first, that chronically elevated blood L-phenylalanine (Phe) inhibits the transport of L-tyrosine (Tyr) and L-tryptophan (Trp), the substrates for dopamine and serotonin synthesis respectively, into brain. In the second hypothesis, elevated Phe competitively inhibits brain tyrosine hydroxylase (TH) and tryptophan hydroxylase (TPH) activities, the rate limiting steps in dopamine and serotonin synthesis. Dietary supplementation with large neutral amino acids (LNAA) including Tyr and Trp has been recommended for individuals with chronically elevated blood Phe in an attempt to restore amino acid and monoamine homeostasis in brain. As a potential alternative treatment approach, we demonstrate that pharmacologic inhibition of Tyr degradation through oral administration of nitisinone (NTBC) yielded sustained increases in blood and brain Tyr, decreased blood and brain Phe, and consequently increased dopamine synthesis in a murine model of PKU. Our results suggest that Phe-mediated inhibition of TH activity is the likely mechanism of impaired dopamine synthesis in PKU. Pharmacologic inhibition of Tyr degradation may be a promising adjunct therapy for CNS monoamine neurotransmitter deficiency in hyperphenylalaninemic individuals with PKU. PMID:24487571

L-tyrosine induces the production of a pyomelanin-like pigment by the parasitic yeast-form of Histoplasma capsulatum.

Science.gov (United States)

Almeida-Paes, Rodrigo; Almeida-Silva, Fernando; Pinto, Gabriela Costa Maia; Almeida, Marcos de Abreu; Muniz, Mauro de Medeiros; Pizzini, Claudia Vera; Gerfen, Gary J; Nosanchuk, Joshua Daniel; Zancopé-Oliveira, Rosely Maria

2018-06-01

Melanization of Histoplasma capsulatum remains poorly described, particularly in regards to the forms of melanin produced. In the present study, 30 clinical and environmental H. capsulatum strains were grown in culture media with or without L-tyrosine under conditions that produced either mycelial or yeast forms. Mycelial cultures were not melanized under the studied conditions. However, all strains cultivated under yeast conditions produced a brownish to black soluble pigment compatible with pyomelanin when grew in presence of L-tyrosine. Sulcotrione inhibited pigment production in yeast cultures, strengthening the hyphothesis that H. capsulatum yeast forms produce pyomelanin. Since pyomelanin is produced by the fungal parasitic form, this pigment may be involved in H. capsulatum virulence.

Crystallization and preliminary X-ray crystallographic analysis of l-rhamnose isomerase with a novel high thermostability from Bacillus halodurans

International Nuclear Information System (INIS)

Doan, Thi-Ngoc-Thanh; Prabhu, Ponnandy; Kim, Jin-Kwang; Ahn, Yeh-Jin; Natarajan, Sampath; Kang, Lin-Woo; Park, Geon Tae; Lim, Sang-Boem; Lee, Jung-Kul

2010-01-01

l-Rhamnose isomerase (l-RhI) from B. halodurans has been purified and crystallized. The crystals of l-RhI belonged to the monoclinic space group P2 1 , with unit-cell parameters a = 83.2, b = 164.9, c = 92.0 Å, β = 116.0°, and diffracted to 2.5 Å resolution. l-Rhamnose isomerases catalyze isomerization between l-rhamnose (6-deoxy-l-mannose) and l-rhamnulose (6-deoxy-l-fructose), which is the first step in rhamnose catabolism. l-Rhamnose isomerase from Bacillus halodurans ATCC BAA-125 (BHRI) exhibits interesting characteristics such as high thermostability and selective substrate specificity. BHRI fused with an HHHHHH sequence was purified and crystallized in order to elucidate the molecular basis of its unique enzymatic properties. The crystals were grown by the hanging-drop vapour-diffusion method and belonged to the monoclinic space group P2 1 , with unit-cell parameters a = 83.2, b = 164.9, c = 92.0 Å, β = 116.0°. Diffraction data were collected to 2.5 Å resolution. According to a Matthews coefficient calculation, there are four monomers in the asymmetric unit with a V M of 3.0 Å 3 Da −1 and a solvent content of 59.3%. The initial structure of BHRI has been determined by the molecular-replacement method

Remote-controlled module-assisted synthesis of O-(2-[18F]fluoroethyl)-L-tyrosine as tumor PET tracer using two different radiochemical routes

International Nuclear Information System (INIS)

Wang Mingwei; Yin Duanzhi; Zhang Lan; Zhou Wei; Wang Yongxian

2006-01-01

The positron-emitter fluorine-18 labeled amino acid O-(2-[ 18 F]fluoroethyl)-L-tyrosine ([ 18 F]FET) has shown very promising perspectives for brain tumor diagnosis with positron emission tomography (PET). There have been two existing preparation routes of [ 18 F]FET named direct nucleophilic radiofiuorination of protected L-tyrosine and radiofiuoroallcylation of unprotected L-tyrosine, respectively. A general module was designed specifically for the routine synthesis of [ 18 F]FET, which could be suitable for the present two chemical methods with simple modifications. The fluorinated intermediates and the final product were separated and purified using solid phase extraction (SPE) on the Sep-Pak silica plus cartridge instead of the time-consuming high performance liquid chromatography (HPLC) procedures. The total synthesis time was about 50-60 rain with good radiochemical yield (about 20-40%, no-decay-corrected) and good radiochemical purity (more than 97%) for both the synthetic methods. (authors)

The hydroxynitrile lyase from almond: crystal structure and mechanistical studies

International Nuclear Information System (INIS)

Dreveny, Ingrid

2001-09-01

Cyanogenesis is a defense process of several thousand plant species. Hydroxynitrile lyase (HNL), a key enzyme of this process, cleaves a cyanohydrin precursor into hydrocyanic acid and the corresponding aldehyde or ketone. The reverse reaction constitutes an important tool in industrial biocatalysis. Different classes of hydroxynitrile lyases have convergently evolved from FAD-dependent oxidoreductases, α/β hydrolases and alcohol dehydrogenases. The FAD-dependent hydroxynitrile lyases (FAD-HNLs) carry a flavin cofactor whose redox properties appear to be unimportant for catalysis. The high resolution crystal structure of the hydroxynitrile lyase from almond (Prunus amygdalus), PaHNL1, has been determined and constitutes the first 3D structure of an FAD-HNL. The overall fold and the architecture of the active site region showed that PaHNL1 belongs to the glucose-methanol-choline-oxidoreductase family, with closest structural similarity to glucose oxidase. There is strong evidence from the sequence and the reaction product that FAD-dependent hydroxynitrile lyases have evolved from an aryl alcohol oxidizing precursor. Structures of PaHNL1 in complex with its natural substrate mandelonitrile and the competitive inhibitor benzyl alcohol provided insight into the residues involved in catalysis and a mechanism without participation of the cofactor could be suggested. Although the catalytic residues differ between the α/β-hydrolase-type HNLs and PaHNL1, common general features relevant for hydroxynitrile lyase activity could be proposed. (author)

In vitro antioxidant evaluation and total phenolics of methanolic leaf extracts of Nyctanthes arbor-tristis L.

Science.gov (United States)

Michael, J Savarimuthu; Kalirajan, A; Padmalatha, C; Singh, A J A Ranjit

2013-09-01

To investigate the in vitro antioxidant activity and total phenolic content of the methanolic leaf extract of Nyctanthes arbor-tristis L. (NA). The sample was tested using five in vitro antioxidant methods (1, 1-diphenyl-2-picryl hydrazine radical scavenging activity (DPPH), hydroxyl radical-scavenging activity (-OH), nitric oxide scavenging activity (NO), superoxide radical-scavenging activity, and total antioxidant activity) to evaluate the in vitro antioxidant potential of NA and the total phenolic content (Folin-Ciocalteu method). The extract showed good free radical scavenging property which was calculated as an IC50 value. IC50 (Half maximal inhibitory concentration) of the methanolic extract was found to be 57.93 μg·mL(-1) for DPPH, 98.61 μg·mL(-1) for -OH, 91.74 μg·mL(-1) for NO, and 196.07 μg·mL(-1) for superoxide radical scavenging activity. Total antioxidant capacity of the extract was found to be (1198 ± 24.05) mg ascorbic acid for the methanolic extract. Free radical scavenging activity observed in the extracts of NA showed a concentration-dependent reaction. The in vitro scavenging tested for free radicals was reported to be due to high phenolic content in the leaf extract. The leaf extract of NA showed the highest total phenolic content with a value of 78.48 ± 4.2 equivalent mg TAE/g (tannic acid equivalent). N. arbor-tristis leaf extract exhibited potent free radical scavenging activity. The finding suggests that N. arbor-tristis leaves could be a potential source of natural antioxidant. Copyright © 2013 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

Functional analysis of thermostable proteins involved in carbohydrate metabolism

NARCIS (Netherlands)

Akerboom, A.P.

2007-01-01

Thermostable proteins can resist temperature stress whilst keeping their integrity and functionality. In many cases, thermostable proteins originate from hyperthermophilic microorganisms that thrive in extreme environments. These systems are generally located close to geothermal (volcanic) activity,

L-tyrosine hydrochloride crystals under high pressures via Raman Spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Santos, C.A.A.S.; Facanha Filho, P.F.; Santos, A.O. dos; Ribeiro, L.H.L.; Victor, F.M.S.; Abreu, D.C.; Carvalho, J.O.; Soares, R.A.; Sousa, J.C.F.; Lima, R.C.; Cavaignac, A.O. [Universidade Federal do Maranhao (UFMA), MA (Brazil)

2016-07-01

Full text: Amino acid single crystals have been attracted researchers in recent years due to their potential applications as second harmonic generator. The goal of this work is to produce semi organic single crystals of L-tyrosine hydrochloride (LTHCl) and verify the behavior of their vibrational normal modes under high pressures and the stability of material in these conditions extremes. The LTHCl single crystals were produced for solubilization of amino acid L-tyrosine in hydrochloric acid by slow evaporation technique of the solvent in room temperature. The technique of X-ray diffraction (XRD) and the refinement of structure by the Rietveld method were used to confirm the crystal structure. The LTHCl crystal belongs to the monoclinic crystal system having two molecules per unit cell. The refinement by the Rietveld method showed good results with Rwp = 8.49% and Rp = 6.29% with S = 1.13. Raman scattering measurements as a function of pressure was performed in a piece of crystal from the ambient pressure to 7.2 GPa and Nujol was used as pressure medium. It was observed the appearance of a weak band around 163 cm-1 between pressures of 0.5 and 1.0 GPa, which characterize an phase transition undergone by the crystal. Moreover, this band gains intensity as pressure increases while gradual decreasing relative intensity of the very strong band at 123 cm-1 for all range of pressure also was observed. In fact, almost all bands of the spectra have undergone strong decreasing up to 7.2 GPa. However, on release of pressure the crystal has reached the original phase again. Therefore, the results showed this material cannot be suitable for the application (NLO) in this range of pressure. (author)

Stimulation of {sup 125}I-3-iodo-{alpha}-methyl-L-tyrosine uptake in Chinese hamster ovary (CHO-K1) cells by tyrosine esters

Energy Technology Data Exchange (ETDEWEB)

Shikano, Naoto [Department of Radiological Sciences, Center for Medical Sciences and Center for Humanities and Sciences, Ibaraki Prefectural University of Health Sciences, Inashiki-gun, Ibaraki (Japan)], E-mail: sikano@ipu.ac.jp; Ogura, Masato; Sagara, Jun-ichi; Nakajima, Syuichi [Department of Radiological Sciences, Center for Medical Sciences and Center for Humanities and Sciences, Ibaraki Prefectural University of Health Sciences, Inashiki-gun, Ibaraki (Japan); Kobayashi, Masato [Division of Health Science, Graduate School of Health Sciences, Kanazawa University, Kanazawa, Ishikawa (Japan); Baba, Takeshi; Yamaguchi, Naoto; Iwamura, Yukio; Kubota, Nobuo [Department of Radiological Sciences, Center for Medical Sciences and Center for Humanities and Sciences, Ibaraki Prefectural University of Health Sciences, Inashiki-gun, Ibaraki (Japan); Kawai, Keiichi [Division of Health Science, Graduate School of Health Sciences, Kanazawa University, Kanazawa, Ishikawa (Japan)

2010-02-15

Introduction: Transport of the amino acid analog {sup 123}I-3-iodo-{alpha}-methyl-L-tyrosine, which is used in clinical SPECT imaging, occurs mainly via L-type amino acid transporter type 1 (LAT1; an amino acid exchanger). As LAT1 is highly expressed in actively proliferating tumors, we made a preliminary investigation of the effects of amino acid esters on enhancement of {sup 125}I-3-iodo-{alpha}-methyl-L-tyrosine (IMT) uptake via LAT1 in Chinese hamster ovary (CHO-K1) cells. Methods: Because the sequence of the CHO-K1 LAT1 gene is not available, we confirmed LAT1 expression through IMT (18.5 kBq) uptake mechanisms using specific inhibitors. L-Gly, L-Ser, L-Leu, L-Phe, L-Met, L-Tyr, D-Tyr, L-Val and L-Lys ethyl/methyl esters were tested in combination with IMT. Time-course studies over a 3-h period were conducted, and the concentration dependence of L-Tyr ethyl and methyl esters (0.001 to 10 mM) in combination with IMT was also examined. For a proof of de-esterification of L- and D-Tyr ethyl and methyl esters in the cells (by enzymatic attack or other cause), the concentration of L- and D-Tyr was analyzed by high-performance liquid chromatography of the esters in phosphate buffer (pH 7.4) and cell homogenates at 37 deg. C or under ice-cold conditions. Results: Inhibition tests suggested that LAT1 is involved in IMT uptake by CHO-K1 cells. Co-administration of 1 mM of L-Tyr ethyl or methyl ester with IMT produced the greatest enhancement. The de-esterification reaction was stereo selective and temperature dependent in the homogenate. De-esterification kinetics were very fast in the homogenate and very slow in the phosphate buffer. Conclusions: The L-Tyr ethyl or methyl esters were the most effective enhancers of IMT uptake into CHO-K1 cells and acted by trans-stimulation of the amino acid exchange function of LAT1. This result suggests that de-esterification in the cells may be caused by enzymatic attack. We will use IMT and L-Tyr ethyl or methyl esters to examine

Studies on pectin lyase

NARCIS (Netherlands)

Houdenhoven, van F.E.A.

1975-01-01

The pectin lyase activity in the commercial enzyme preparation Ultrazym originates from more then one type of enzyme; two of them, accounting for 95 % of the total activity, have been completely purified. As purity criteria specific activity, polyacrylamide disc gel electrophoresis and SDS

A feasible enzymatic process for D-tagatose production by an immobilized thermostable L-arabinose isomerase in a packed-bed bioreactor.

Science.gov (United States)

Kim, Hye-Jung; Ryu, Se-Ah; Kim, Pil; Oh, Deok-Kun

2003-01-01

To develop a feasible enzymatic process for d-tagatose production, a thermostable l-arabinose isomerase, Gali152, was immobilized in alginate, and the galactose isomerization reaction conditions were optimized. The pH and temperature for the maximal galactose isomerization reaction were pH 8.0 and 65 degrees C in the immobilized enzyme system and pH 7.5 and 60 degrees C in the free enzyme system. The presence of manganese ion enhanced galactose isomerization to tagatose in both the free and immobilized enzyme systems. The immobilized enzyme was more stable than the free enzyme at the same pH and temperature. Under stable conditions of pH 8.0 and 60 degrees C, the immobilized enzyme produced 58 g/L of tagatose from 100 g/L galactose in 90 h by batch reaction, whereas the free enzyme produced 37 g/L tagatose due to its lower stability. A packed-bed bioreactor with immobilized Gali152 in alginate beads produced 50 g/L tagatose from 100 g/L galactose in 168 h, with a productivity of 13.3 (g of tagatose)/(L-reactor.h) in continuous mode. The bioreactor produced 230 g/L tagatose from 500 g/L galactose in continuous recycling mode, with a productivity of 9.6 g/(L.h) and a conversion yield of 46%.

Brain tumors : L-[1-C-11]tyrosine PET for visualization and quantification of protein synthesis rate

NARCIS (Netherlands)

Pruim, J; Willemsen, A T; Molenaar, W M; Waarde, A van; Paans, A M; Heesters, M A; Go, K G; Visser, Gerben; Franssen, E J; Vaalburg, W

1995-01-01

PURPOSE: Positron emission tomography (PET) with the amino acid tracer L-[1-C-11]-tyrosine was evaluated in 27 patients with primary and recurrent brain tumors. MATERIALS AND METHODS: Patients underwent either static (n = 14) or dynamic PET (n = 13), with quantification of protein synthesis rate

Schiff bases derived from L-Tyrosine L-Tryptophan and their Cu(II) chelates as effective means for preventive-treatment of radiation injuries

International Nuclear Information System (INIS)

Malakyan, M.H.; Bajinyan, S.A.; Matosyan, V.H.; Tonoyan, V.J.; Babayan, K.N.; Boyajyan, A.S.; Yeghiazaryan, D.E.; Vardevanyan, L.A.; Sorenson, J.R.J.

2008-01-01

Full text: Study on essential metallo element chelates as radioprotectors presents a promising direction in a search for and development of novel anti-radiation agents and offers a new approach to overcome the pathological effects of ionizing radiation. The key idea elucidating the radioprotective effects of metallo element-containing chelates of amino acid derivatives is their role in stimulation of de novo synthesis of metallo element-dependent enzymes required for recovery of hemopoietic activity and immuno competency lost as a consequence of radiation damage. Aimed to develop novel anti-radiation remedies of less toxicity and high efficacy, Schiff bases derived from L-Tyrosine and L-Tryptophan and their Cu(II) chelates were synthesized. In experiments in vitro and in vivo biological and pharmacological properties of the mentioned Schiff Bases and their copper complexes are under study. According to the results obtained, L-Tyrosinate and L-Tryptophanate Schiff bases are low toxic compounds with a weak antioxidant activity and exert radioprotective effects in case of animal X-ray irradiation at a dose level equal or less than LD 50/30 . Unlike Schiff Bases, their appropriate Cu(II) chelates possess high anti radical/antioxidant activity and manifest expressed radio-protective action at LD 100/30 dose of ionizing radiation. Anti-radiation effects of amino acid Schiff bases and their metallo chelates are manifested in case of both subcutaneous and oral single administration to the animal organism at 10, 20, or 40 mg/kg 1, 3, 6, or 24 hours prior to radiation exposure. Conclusions are drawn basing on determinations of survival and average life-span indices of irradiated animals, as well as on studies for their hematological, biochemical, immunological, biophysical indices. It is revealed that on the background of preliminary administration of the compounds studied to the animal organism the characteristics of DNA are significantly improved, the immune status

High-pressure Raman spectra and DFT calculations of L-tyrosine hydrochloride crystal

Science.gov (United States)

dos Santos, C. A. A. S. S.; Carvalho, J. O.; da Silva Filho, J. G.; Rodrigues, J. L.; Lima, R. J. C.; Pinheiro, G. S.; Freire, P. T. C.; Façanha Filho, P. F.

2018-02-01

High-pressure Raman spectra of L-tyrosine hydrochloride crystal were obtained from 1.0 atm to 7.0 GPa in the 90-1800 cm-1 spectral region. At atmospheric pressure, the Raman spectrum was obtained in the 50-3200 cm-1 spectral range and the assignment of the normal modes based on density functional theory calculations was provided. We found good correspondence between the calculated and the observed intramolecular geometry parameters. This confirms the correct assignment of the normal modes, since it was crucial to understand the meaning of the changes observed in particular Raman active modes. Here we show that bands associated with internal modes undergo slight modifications during compression. However, an inversion of the relative intensity of bands around 125 cm-1 as well as a change of slope dω/dP from 1.0 to 1.5 GPa was understood as a conformational change involving a torsion of the L-tyrosine molecule. As a consequence, it is possible to conclude that the crystal remained in the same monoclinic structure in the 1 atm-7.0 GPa interval, although conformational change of the molecule was verified. A comparison of our results with other selected studies provided insights about the role of the amino acid side chain on the arrangement of hydrogen bonds. Finally, when the pressure was released back to 1 atm, the Raman spectrum was recovered and no hysteresis was observed.

AlgM4: A New Salt-Activated Alginate Lyase of the PL7 Family with Endolytic Activity

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Guiyuan Huang

2018-04-01

Full Text Available Alginate lyases are a group of enzymes that catalyze the depolymerization of alginates into oligosaccharides or monosaccharides. These enzymes have been widely used for a variety of purposes, such as producing bioactive oligosaccharides, controlling the rheological properties of polysaccharides, and performing structural analyses of polysaccharides. The algM4 gene of the marine bacterium Vibrio weizhoudaoensis M0101 encodes an alginate lyase that belongs to the polysaccharide lyase family 7 (PL7. In this study, the kinetic constants Vmax (maximum reaction rate and Km (Michaelis constant of AlgM4 activity were determined as 2.75 nmol/s and 2.72 mg/mL, respectively. The optimum temperature for AlgM4 activity was 30 °C, and at 70 °C, AlgM4 activity dropped to 11% of the maximum observed activity. The optimum pH for AlgM4 activity was 8.5, and AlgM4 was completely inactive at pH 11. The addition of 1 mol/L NaCl resulted in a more than sevenfold increase in the relative activity of AlgM4. The secondary structure of AlgM4 was altered in the presence of NaCl, which caused the α-helical content to decrease from 12.4 to 10.8% and the β-sheet content to decrease by 1.7%. In addition, NaCl enhanced the thermal stability of AlgM4 and increased the midpoint of thermal denaturation (Tm by 4.9 °C. AlgM4 exhibited an ability to degrade sodium alginate, poly-mannuronic acid (polyM, and poly-guluronic acid (polyG, resulting in the production of oligosaccharides with a degree of polymerization (DP of 2–9. AlgM4 possessed broader substrate, indicating that it is a bifunctional alginate lyase. Thus, AlgM4 is a novel salt-activated and bifunctional alginate lyase of the PL7 family with endolytic activity.

Optimization of laccase production by two strains of Ganoderma lucidum using phenolic and metallic inducers

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Francisco Kuhar

Full Text Available Ganoderma lucidum (Curtis P. Karst is a white rot fungus that is able to degrade the lignin component in wood. The ability of two strains of this species to produce the ligninolytic enzyme laccase was assessed. After the evaluation of induction with heavy metals and phenolic compounds, it was found that among the tested substances, copper and ferulic acid are the best laccase inducers. It was also observed that the two types of inducers (phenolic and metallic produce different electrophoretic patterns of laccase activity. Optimized concentrations of inducers were obtained through a factorial design and the thermal stability of optimized supernatants was studied at a wide range of acidic pH. We found that the enzyme is more thermostable at higher pH values.

Possible regulatory role of phenylalanine ammonia-lyase in the production of anthocyanins in asparagus (Asparagus officinalis L)

NARCIS (Netherlands)

Flores, F.B.; Oosterhaven, J.; Martinez-Madrid, M.C.; Romojaro, F.

2005-01-01

The regulatory role of phenylalanine ammonia-lyase (PAL) in the light-induced accumulation of anthocyanins in the epidermis of asparagus spears has been analysed. A correlation between the stimulation of PAL activity and the rise in total anthocyanin content has been observed. Light radiation

Probing the active site of MIO-dependent 2,3-aminomutases, key catalysts in the biosynthesis of beta-amino acids incorporated in secondary metabolites

Science.gov (United States)

Bruner, Steven D.; Cooke, Heather

2012-01-01

The tyrosine aminomutase SgTAM produces (S)-β-tyrosine from l-tyrosine in the biosynthesis of the enediyne antitumor antibiotic C-1027. This conversion is promoted by the methylideneimidazole-5-one (MIO) prosthetic group. MIO was first identified in the homologous family of ammonia lyases, which deaminate aromatic amino acids to form α,β-unsaturated carboxylates. Studies of substrate specificity have been described for lyases but there have been no reports in altering the substrate specificity of aminomutases. Furthermore, it remains unclear as to what structural properties are responsible for catalyzing the presumed readdition of the amino group into the α,β-unsaturated intermediates to form β-amino acids. Attempts to elucidate specificity and mechanistic determinants of SgTAM have also proved to be difficult as it is recalcitrant to perturbations to the active site via mutagenesis. An X-ray co-crystal structure of the SgTAM mutant of the catalytic base with l-tyrosine verified important substrate binding residues as well as the enzymatic base. Further mutagenesis revealed that removal of these crucial interactions renders the enzyme inactive. Proposed structural determinants for mutase activity probed via mutagenesis, time-point assays and X-ray crystallography revealed a complicated role for these residues in maintaining key quaternary structure properties that aid in catalysis. PMID:20577998

Isolation and characterization of phenol degrading yeast.

Science.gov (United States)

Patel, Riddhi; Rajkumar, Shalini

2009-04-01

A phenol degrading yeast isolate was identified and characterized from the soil sample collected from a landfill site, in Ahmedabad, India, by plating the soil dilutions on Sabouraud's Dextrose Agar. The microscopic studies and biochemical tests indicated the isolate to be Saccharomyces cerevisiae. The phenol degrading potential of the isolate was measured by inoculation of pure culture in the mineral medium containing various phenol concentrations ranging from 100 to 800 mg l(-1 )and monitoring phenol disappearance rate at regular intervals of time. Growth of the isolate in mineral medium with various phenol concentrations was monitored by measuring the turbidity (OD(600) nm). The results showed that the isolated yeast was tolerant to phenol up to 800 mg(-1). The phenol degradation ranged from 8.57 to 100% for the concentration of phenol from 800 mg l(-1 )to 200 mg l(-1), respectively. ((c) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim).

Cloning and Expression Analysis of Phenylalanine Ammonia-Lyase Gene in the Mycelium and Fruit Body of the Edible Mushroom Flammulina velutipes

Science.gov (United States)

Yun, Yeo Hong; Koo, Ja Sun

2015-01-01

Phenylalanine ammonia-lyase (PAL) gene is known to be expressed in plants, and is involved in the differentiation, growth and synthesis of secondary metabolites. However, its expression in fungi remains to be explored. To understand its expression in mushroom fungi, the PAL gene of the edible mushroom Flammulina velutipes (Fvpal) was cloned and characterized. The cloned Fvpal consists of 2,175 bp, coding for a polypeptide containing 724 amino acids and having 11 introns. The translated amino acid sequence of Fvpal shares a high identity (66%) with that of ectomycorrhizal fungus Tricholoma matsutake. Distinctively, the Fvpal expression in the mycelium was higher in minimal medium supplemented with L-tyrosine than with other aromatic amino acids. During cultivation of the mushroom on sawdust medium, Fvpal expression in the fruit body correspondingly increased as the mushroom grew. In the fruiting body, Fvpal was expressed more in the stipe than in the pileus. These results suggest that F. velutipes PAL activity differs in the different organs of the mushroom. Overall, this is first report to show that the PAL gene expression is associated with mushroom growth in fungi. PMID:26539050

Effective L-Tyrosine Hydroxylation by Native and Immobilized Tyrosinase.

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Małgorzata Cieńska

Full Text Available Hydroxylation of L-tyrosine to 3,4-dihydroxyphenylalanine (L-DOPA by immobilized tyrosinase in the presence of ascorbic acid (AH2, which reduces DOPA-quinone to L-DOPA, is characterized by low reaction yields that are mainly caused by the suicide inactivation of tyrosinase by L-DOPA and AH2. The main aim of this work was to compare processes with native and immobilized tyrosinase to identify the conditions that limit suicide inactivation and produce substrate conversions to L-DOPA of above 50% using HPLC analysis. It was shown that immobilized tyrosinase does not suffer from partitioning and diffusion effects, allowing a direct comparison of the reactions performed with both forms of the enzyme. In typical processes, additional aeration was applied and boron ions to produce the L-DOPA and AH2 complex and hydroxylamine to close the cycle of enzyme active center transformations. It was shown that the commonly used pH 9 buffer increased enzyme stability, with concomitant reduced reactivity of 76%, and that under these conditions, the maximal substrate conversion was approximately 25 (native to 30% (immobilized enzyme. To increase reaction yield, the pH of the reaction mixture was reduced to 8 and 7, producing L-DOPA yields of approximately 95% (native enzyme and 70% (immobilized. A three-fold increase in the bound enzyme load achieved 95% conversion in two successive runs, but in the third one, tyrosinase lost its activity due to strong suicide inactivation caused by L-DOPA processing. In this case, the cost of the immobilized enzyme preparation is not overcome by its reuse over time, and native tyrosinase may be more economically feasible for a single use in L-DOPA production. The practical importance of the obtained results is that highly efficient hydroxylation of monophenols by tyrosinase can be obtained by selecting the proper reaction pH and is a compromise between complexation and enzyme reactivity.

Effective L-Tyrosine Hydroxylation by Native and Immobilized Tyrosinase.

Science.gov (United States)

Cieńska, Małgorzata; Labus, Karolina; Lewańczuk, Marcin; Koźlecki, Tomasz; Liesiene, Jolanta; Bryjak, Jolanta

2016-01-01

Hydroxylation of L-tyrosine to 3,4-dihydroxyphenylalanine (L-DOPA) by immobilized tyrosinase in the presence of ascorbic acid (AH2), which reduces DOPA-quinone to L-DOPA, is characterized by low reaction yields that are mainly caused by the suicide inactivation of tyrosinase by L-DOPA and AH2. The main aim of this work was to compare processes with native and immobilized tyrosinase to identify the conditions that limit suicide inactivation and produce substrate conversions to L-DOPA of above 50% using HPLC analysis. It was shown that immobilized tyrosinase does not suffer from partitioning and diffusion effects, allowing a direct comparison of the reactions performed with both forms of the enzyme. In typical processes, additional aeration was applied and boron ions to produce the L-DOPA and AH2 complex and hydroxylamine to close the cycle of enzyme active center transformations. It was shown that the commonly used pH 9 buffer increased enzyme stability, with concomitant reduced reactivity of 76%, and that under these conditions, the maximal substrate conversion was approximately 25 (native) to 30% (immobilized enzyme). To increase reaction yield, the pH of the reaction mixture was reduced to 8 and 7, producing L-DOPA yields of approximately 95% (native enzyme) and 70% (immobilized). A three-fold increase in the bound enzyme load achieved 95% conversion in two successive runs, but in the third one, tyrosinase lost its activity due to strong suicide inactivation caused by L-DOPA processing. In this case, the cost of the immobilized enzyme preparation is not overcome by its reuse over time, and native tyrosinase may be more economically feasible for a single use in L-DOPA production. The practical importance of the obtained results is that highly efficient hydroxylation of monophenols by tyrosinase can be obtained by selecting the proper reaction pH and is a compromise between complexation and enzyme reactivity.

Effective L-Tyrosine Hydroxylation by Native and Immobilized Tyrosinase

Science.gov (United States)

Lewańczuk, Marcin; Koźlecki, Tomasz; Liesiene, Jolanta; Bryjak, Jolanta

2016-01-01

Hydroxylation of L-tyrosine to 3,4-dihydroxyphenylalanine (L-DOPA) by immobilized tyrosinase in the presence of ascorbic acid (AH2), which reduces DOPA-quinone to L-DOPA, is characterized by low reaction yields that are mainly caused by the suicide inactivation of tyrosinase by L-DOPA and AH2. The main aim of this work was to compare processes with native and immobilized tyrosinase to identify the conditions that limit suicide inactivation and produce substrate conversions to L-DOPA of above 50% using HPLC analysis. It was shown that immobilized tyrosinase does not suffer from partitioning and diffusion effects, allowing a direct comparison of the reactions performed with both forms of the enzyme. In typical processes, additional aeration was applied and boron ions to produce the L-DOPA and AH2 complex and hydroxylamine to close the cycle of enzyme active center transformations. It was shown that the commonly used pH 9 buffer increased enzyme stability, with concomitant reduced reactivity of 76%, and that under these conditions, the maximal substrate conversion was approximately 25 (native) to 30% (immobilized enzyme). To increase reaction yield, the pH of the reaction mixture was reduced to 8 and 7, producing L-DOPA yields of approximately 95% (native enzyme) and 70% (immobilized). A three-fold increase in the bound enzyme load achieved 95% conversion in two successive runs, but in the third one, tyrosinase lost its activity due to strong suicide inactivation caused by L-DOPA processing. In this case, the cost of the immobilized enzyme preparation is not overcome by its reuse over time, and native tyrosinase may be more economically feasible for a single use in L-DOPA production. The practical importance of the obtained results is that highly efficient hydroxylation of monophenols by tyrosinase can be obtained by selecting the proper reaction pH and is a compromise between complexation and enzyme reactivity. PMID:27711193

A comparison of the phenolic profile and antioxidant activity of different Cichorium spinosum L. ecotypes.

Science.gov (United States)

Petropoulos, Spyridon A; Fernandes, Ângela; Barros, Lillian; Ferreira, Isabel Cfr

2018-01-01

Wild greens are considered a rich source of phenolic compounds and antioxidants and an essential part of the so-called Mediterranean diet. In the present study, Cichorium spinosum L. ecotypes, cultivated or collected in situ from wild plants from the eastern Mediterranean, were evaluated regarding their phenolic composition and antioxidant activity. Significant differences were observed among the various studied ecotypes regarding their phenolic compound content and profile, especially between wild and cultivated ecotypes, as well as the phenolic acid content between commercial products and cultivated plants. The antioxidant activity also varied among the various studied ecotypes and growing conditions, with commercial products having the highest antioxidant activity, whereas wild ecotypes showed lower antioxidant activity. Cichorium spinosum leaves are a rich source of chicoric and 5-O-caffeoylquinic acid, while significant differences in total phenolic acids, flavonoids and phenolic compound content and in antioxidant activity were observed among the studied ecotypes, as well as between the tested growing conditions. According to the results of the present study, further valorization of C. spinosum species has great potential, since it could be used as a new alternative species in the food industry. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Evaluation of Antioxidant Activity and Phenolic Content in Different Salvia officinalis L. Extracts

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Ana Viorica Pop (Cuceu

2015-11-01

Full Text Available The use of medicinal plants to improve health is an ancient practice and in recent years it has been observed an increasing interest of scientific researchers for the study of plants with biological properties and active principles responsible for their therapeutic effects. Salvia officinalis L. is considered the queen of herbs and belongs to the Lamiaceae (Labiatae family. Due to the increasing interest in plants health benefits, the aim of the present study was to characterize various extracts of Romanian sage regarding their content in compounds with antioxidant activity. Three different techniques and five solvents were used for extraction of bioactive compounds from Salvia officinalis L. The total phenolic content and the antioxidant activity of plant extract were determined by Folin-Ciocalteu method and respectively by the 2,2-diphenyl-1-picrylhydrazyl (DPPH free radical scavenging assay. Methanolic extract exhibited the highest content in phenolic compound (1974.89 mg GAE/100g dw as well ass the strongest antioxidant capacity (85.12%.

Purification and characterization of selenocysteine beta-lyase from Citrobacter freundii

International Nuclear Information System (INIS)

Chocat, P.; Esaki, N.; Tanizawa, K.; Nakamura, K.; Tanaka, H.; Soda, K.

1985-01-01

The purification and characterization of bacterial selenocysteine beta-lyase, an enzyme which specifically catalyzes the cleavage of L-selenocysteine to L-alanine and Se0, are presented. The enzyme, purified to near homogeneity from Citrobacter freundii, is monomeric with a molecular weight of ca. 64,000 and contains 1 mol of pyridoxal 5'-phosphate as a cofactor per mol of enzyme. L-Selenocysteine is the sole substrate. L-Cysteine is a competitive inhibitor of the enzyme. The enzyme also catalyzes the alpha, beta elimination of beta-chloro-L-alanine to form NH 3 , pyruvate, and Cl- and is irreversibly inactivated during the reaction. The physicochemical properties, e.g., amino acid composition and subunit structure, of the bacterial enzyme are fairly different from those of the pig liver enzyme. However, the catalytic properties of both enzymes, e.g., substrate specificity and inactivation by the substrate or a mechanism-based inactivator, beta-chloro-L-alanine, are very similar

Engineering Thermostable Microbial Xylanases Toward its Industrial Applications.

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Kumar, Vishal; Dangi, Arun Kumar; Shukla, Pratyoosh

2018-03-01

Xylanases are one of the important hydrolytic enzymes which hydrolyze the β-1, 4 xylosidic linkage of the backbone of the xylan polymeric chain which consists of xylose subunits. Xylanases are mainly found in plant cell walls and are produced by several kinds of microorganisms such as fungi, bacteria, yeast, and some protozoans. The fungi are considered as most potent xylanase producers than that of yeast and bacteria. There is a broad series of industrial applications for the thermostable xylanase as an industrial enzyme. Thermostable xylanases have been used in a number of industries such as paper and pulp industry, biofuel industry, food and feed industry, textile industry, etc. The present review explores xylanase-substrate interactions using gene-editing tools toward the comprehension in improvement in industrial stability of xylanases. The various protein-engineering and metabolic-engineering methods have also been explored to improve operational stability of xylanase. Thermostable xylanases have also been used for improvement in animal feed nutritional value. Furthermore, they have been used directly in bakery and breweries, including a major use in paper and pulp industry as a biobleaching agent. This present review envisages some of such applications of thermostable xylanases for their bioengineering.

Molecular cloning and characterization of l-methionine γ-lyase from Streptomyces avermitilis.

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Kudou, Daizou; Yasuda, Eri; Hirai, Yoshiyuki; Tamura, Takashi; Inagaki, Kenji

2015-10-01

A pyridoxal 5'-phosphate-dependent methionine γ-lyase (MGL) was cloned from Streptomyces avermitilis catalyzed the degradation of methionine to α-ketobutyrate, methanethiol, and ammonia. The sav7062 gene (1,242 bp) was corresponded to 413 amino acid residues with a molecular mass of 42,994 Da. The deduced amino acid sequence showed a high degree of similarity to those of other MGL enzymes. The sav7062 gene was overexpressed in Escherichia coli. The enzyme was purified to homogeneity and exhibited the MGL catalytic activities. We cloned the enzyme that has the MGL activity in Streptomyces for the first time. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Identification and characterization of phenol hydroxylase from phenol-degrading Candida tropicalis strain JH8.

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Long, Yan; Yang, Sheng; Xie, Zhixiong; Cheng, Li

2014-09-01

The gene phhY encoding phenol hydroxylase from Candida tropicalis JH8 was cloned, sequenced, and expressed in Escherichia coli. The gene phhY contained an open reading frame of 2130 bp encoding a polypeptide of 709 amino acid residues. From its sequence analysis, it is a member of a family of flavin-containing aromatic hydroxylases and shares 41% amino acid identity with phenol hydroxylase from Trichosporon cutaneum. The recombinant phenol hydroxylase exists as a homotetramer structure with a native molecular mass of 320 kDa. Recombinant phenol hydroxylase was insensitive to pH treatment; its optimum pH was at 7.6. The optimum temperature for the enzyme was 30 °C, and its activity was rapidly lost at temperatures above 60 °C. Under the optimal conditions with phenol as substrate, the K(m) and V(max) of recombinant phenol hydroxylase were 0.21 mmol·L(-1) and 0.077 μmol·L(-1)·min(-1), respectively. This is the first paper presenting the cloning and expression in E. coli of the phenol hydroxylase gene from C. tropicalis and the characterization of the recombinant phenol hydroxylase.

An optimized formulation of a thermostable spray dried virus-like particles vaccine against human papillomavirus

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Saboo, Sugandha; Tumban, Ebenezer; Peabody, Julianne; Wafula, Denis; Peabody, David S.; Chackerian, Bryce; Muttil, Pavan

2016-01-01

Existing vaccines against human papillomavirus (HPV) require continuous cold-chain storage. Previously, we developed a bacteriophage virus-like particle (VLP) based vaccine for Human Papillomavirus (HPV) infection, which elicits broadly neutralizing antibodies against diverse HPV types. Here, we formulated these VLPs into a thermostable dry powder using a multi-component excipient system and by optimizing the spray drying parameters using a half-factorial design approach. Dry powder VLPs were stable after spray drying and after long-term storage at elevated temperatures. Immunization of mice with a single dose of reconstituted dry powder VLPs that were stored at 37°C for more than a year elicited high anti-L2 IgG antibody titers. Spray dried thermostable, broadly protective L2 bacteriophage VLPs vaccine could be accessible to remote regions of the world (where ~84% of cervical cancer patients reside) by eliminating the cold-chain requirement during transportation and storage. PMID:27019231

Mutant form C115H of Clostridium sporogenes methionine γ-lyase efficiently cleaves S-Alk(en)yl-l-cysteine sulfoxides to antibacterial thiosulfinates.

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Kulikova, Vitalia V; Anufrieva, Natalya V; Revtovich, Svetlana V; Chernov, Alexander S; Telegin, Georgii B; Morozova, Elena A; Demidkina, Tatyana V

2016-10-01

Pyridoxal 5'-phosphate-dependent methionine γ-lyase (MGL) catalyzes the β-elimination reaction of S-alk(en)yl-l-cysteine sulfoxides to thiosulfinates, which possess antimicrobial activity. Partial inactivation of the enzyme in the course of the reaction occurs due to oxidation of active site cysteine 115 conserved in bacterial MGLs. In this work, the C115H mutant form of Clostridium sporogenes MGL was prepared and the steady-state kinetic parameters of the enzyme were determined. The substitution results in an increase in the catalytic efficiency of the mutant form towards S-substituted l-cysteine sulfoxides compared to the wild type enzyme. We used a sulfoxide/enzyme system to generate antibacterial activity in situ. Two-component systems composed of the mutant enzyme and three S-substituted l-cysteine sulfoxides were demonstrated to be effective against Gram-positive and Gram-negative bacteria and three clinical isolates from mice. © 2016 IUBMB Life, 68(10):830-835, 2016. © 2016 International Union of Biochemistry and Molecular Biology.

Determination of Phenolic Compounds in Wines

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Charalampos Proestos

2012-04-01

Full Text Available Normal 0 false false false MicrosoftInternetExplorer4 Wine contains natural antioxidants such as phenolic compounds also known as bioactive compounds. Samples of commercially available Greek wines were analyzed in order to determine this phenolic content. For the analysis, Reversed Phase-High Performance Liquid Chromatography (RP-HPLC coupled with a multiwavelength Ultraviolet/visible (UV/vis detector was used. The most abundant phenolic substances detected were (+-catechin (13.5-72.4 mg L-1 , gallic acid (0.40-99.47 mg L-1 and caffeic acid (0.87-33.48 mg L-1. The principal component analysis (PCA technique was used to study differentiation among wines according to their production area. Red wines contained more phenolic substances than white ones. Differences of the phenolic composition in wines of the same cultivar were investigated too.

Mentha spicata L. infusions as sources of antioxidant phenolic compounds: emerging reserve lots with special harvest requirements.

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Rita, Ingride; Pereira, Carla; Barros, Lillian; Santos-Buelga, Celestino; Ferreira, Isabel C F R

2016-10-12

Mentha spicata L., commonly known as spearmint, is widely used in both fresh and dry forms, for infusion preparation or in European and Indian cuisines. Recently, with the evolution of the tea market, several novel products with added value are emerging, and the standard lots have evolved to reserve lots, with special harvest requirements that confer them with enhanced organoleptic and sensorial characteristics. The apical leaves of these batches are collected in specific conditions having, then, a different chemical profile. In the present study, standard and reserve lots of M. spicata were assessed in terms of the antioxidants present in infusions prepared from the different lots. The reserve lots presented the highest concentration in all the compounds identified in relation to the standard lots, with 326 and 188 μg mL -1 of total phenolic compounds, respectively. Both types of samples presented rosmarinic acid as the most abundant phenolic compound, at concentrations of 169 and 101 μg mL -1 for reserve and standard lots, respectively. The antioxidant activity was higher in the reserve lots which had the highest total phenolic compounds content, with EC 50 values ranging from 152 to 336 μg mL -1 . The obtained results provide scientific information that may allow the consumer to make a conscientious choice.

Testing the toxicity of metals, phenol, effluents, and receiving waters by root elongation in Lactuca sativa L.

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Lyu, Jie; Park, Jihae; Kumar Pandey, Lalit; Choi, Soyeon; Lee, Hojun; De Saeger, Jonas; Depuydt, Stephen; Han, Taejun

2018-03-01

Phytotoxicity tests using higher plants are among the most simple, sensitive, and cost-effective of the methods available for ecotoxicity testing. In the present study, a hydroponic-based phytotoxicity test using seeds of Lactuca sativa was used to evaluate the water quality of receiving waters and effluents near two industrial sites (Soyo and Daejon) in Korea with respect to the toxicity of 10 metals (As, Cd, Cr, Cu, Fe, Pb, Mn, Hg, Ni, Zn) and phenol, and of the receiving waters and effluents themselves. First, the L. sativa hydroponic bioassay was used to determine whether the receiving water or effluents were toxic; then, the responsible toxicant was identified. The results obtained with the L. sativa bioassay ranked the EC 50 toxicities of the investigated metal ions and phenol as: Cd > Ni > Cu > Zn > Hg > phenol > As > Mn > Cr > Pb > Fe. We found that Zn was the toxicant principally responsible for toxicity in Daejeon effluents. The Daejeon field effluent had a higher Zn concentration than permitted by the effluent discharge criteria of the Ministry of Environment of Korea. Our conclusion on the importance of Zn toxicity was supported by the results of the L. sativa hydroponic assay, which showed that the concentration of Zn required to inhibit root elongation in L. sativa by 50% (EC 50 ) was higher in the Daejeon field effluent than that of pure Zn. More importantly, we proved that the L. sativa hydroponic test method can be applied not only as an alternative tool for determining whether a given waste is acceptable for discharge into public water bodies, but also as an alternative method for measuring the safety of aquatic environments using EC 20 values, with respect to the water pollutants investigated (i.e., Cd, Cr, Cu, Pb, Mn, Hg, Ni, Zn, and phenol). Copyright © 2017. Published by Elsevier Inc.

Mechanism of papain-catalyzed synthesis of oligo-tyrosine peptides.

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Mitsuhashi, Jun; Nakayama, Tsutomu; Narai-Kanayama, Asako

2015-01-01

Di-, tri-, and tetra-tyrosine peptides with angiotensin I-converting enzyme inhibitory activity were synthesized by papain-catalyzed polymerization of L-tyrosine ethyl ester in aqueous media at 30 °C. Varying the reaction pH from 6.0 to 7.5 and the initial concentration of the ester substrate from 25 to 100 mM, the highest yield of oligo-tyrosine peptides (79% on a substrate basis) was produced at pH 6.5 and 75 mM, respectively. In the reaction initiated with 100 mM of the substrate, approx. 50% yield of insoluble, highly polymerized peptides accumulated. At less than 15 mM, the reaction proceeded poorly; however, from 30 mM to 120 mM a dose-dependent increase in the consumption rate of the substrate was observed with a sigmoidal curve. Meanwhile, each of the tri- and tetra-tyrosine peptides, even at approx. 5mM, was consumed effectively by papain but was not elongated to insoluble polymers. For deacylation of the acyl-papain intermediate through which a new peptide bond is made, L-tyrosine ethyl ester, even at 5mM, showed higher nucleophilic activity than di- and tri-tyrosine. These results indicate that the mechanism through which papain polymerizes L-tyrosine ethyl ester is as follows: the first interaction between papain and the ester substrate is a rate-limiting step; oligo-tyrosine peptides produced early in the reaction period are preferentially used as acyl donors, while the initial ester substrate strongly contributes as a nucleophile to the elongation of the peptide product; and the balance between hydrolytic fragmentation and further elongation of oligo-tyrosine peptides is dependent on the surrounding concentration of the ester substrate. Copyright © 2015 Elsevier Inc. All rights reserved.

The comparison of mechanical and thermal properties of carbon nanotubes and graphene naonosheets enhanced phenol-formaldehyde resin

International Nuclear Information System (INIS)

Wu, X.F.; Zhang, Y.; Wu, Y.Z.; Li, Y.J.W.H.

2017-01-01

Graphene naonosheets were prepared via one-pot hydrothermal process in a Teflon-lined autoclave. Moreover, the mechanical and thermal degradation behaviors of the phenol formaldehyde/carbon nanotubes and phenol formaldehyde/graphene naonosheets composites were discussed. Experimental results showed that the graphene naonosheets possessed better performances than that of carbon nanotubes. When the filler loading was 0.6wt%, tensile strength, Young's modulus, compressive strength and modulus of the as-prepared composites reached their maximum values, which were increased by 77.0, 141.3, 109.1 and 114.8% for graphene naonosheets and 54.7, 85.9, 61.7 and 45.2% for carbon nanotubes than those of pure sample, respectively. In addition, both of these two carbon materials could increase the thermo-stability of the matrix. When their usage amount was 0.6wt%, the thermal degradation temperature (at 10% weight loss) was increased to 255.6°C for phenol formaldehyde/graphene naonosheets composites and 253.5°C for phenol formaldehyde/carbon nanotubes composites from 233.6°C for pure sample. (author)

Phenolic Composition, Antioxidant Activity and Anti-Adipogenic Effect of Hot Water Extract from Safflower (Carthamus tinctorius L. Seed

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Seok-Yeong Yu

2013-11-01

Full Text Available This study was to evaluate the phenolic content and composition of Carthamus tinctorius L. seed extract (CSE and to further assess its antioxidant and anti-adipogenic activities using various radical scavenging systems and 3T3-L1 cells. Our results show that the total phenolic and flavonoid contents of CSE were 126.0 ± 2.4 mg GAE/g and 62.2 ± 1.9 mg QE/g, respectively. The major phenolic compounds in CSE was (−-epigallocatechin (109.62 mg/g, with a 4-hydroxy benzhydrazide derivative and gallocatechin present at 18.28 mg/g and 17.02 mg/g, respectively. CSE exhibited remarkable radical scavenging activities, FRAP (ferric reducing antioxidant power and reducing power in a dose-dependent manner. Moreover, the oxygen radical absorbance capacity (ORAC value of CSE (0.1 mg/mL was 62.9 ± 4.7 μM TE (trolox equivalent/g. During adipogenesis, CSE significantly inhibited fat accumulation in 3T3-L1 cells compared with control cells. Overall, these results indicate that CSE might be a valuable source of bioactive compounds that impart functional food and natural antioxidant properties.

Induction of phenolic compounds in Hypericum perforatum L. cells by Colletotrichum gloeosporioides elicitation.

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Conceição, Luis F R; Ferreres, Federico; Tavares, Rui M; Dias, Alberto C P

2006-01-01

Changes in phenolic metabolism after elicitation with Colletotrichum gloeosporioides (CG) has been studied in Hypericum perforatum L. (HP) cell suspension cultures. Soluble phenolics were analysed by HPLC-DAD and HPLC-DAD-MS/MS. HP cultures elicited with the CG elicitor showed a significant increase in xanthone accumulation. Xanthone accumulation increased twelve fold when the cells were primed with methyl-jasmonate (MeJ) or salicylic acid (SA), before elicitation. HP cultures exposed only to MeJ produced a set of flavonoids, the flavones which represent a substantial part (approx. 40%) of the total flavonoids accumulated in these cells. The possible importance of xanthones as a component of defence mechanism of HP against biotic stress is discussed.

Phenolic contents of myrtle (Myrtus communis L. fruits

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Arzu BAYIR YEĞİN

2015-06-01

Full Text Available Myrtle is one of the important natural plant of the Mediterranean region. Fruits are in black and white colour. The earlier studies are mostly focused on the essential oil content of leaves in myrtle plant, whereas the latest studies are dealing with the phenolic compounds of leaves and fruits with their effects on human health. The aim of the study was to determine the phenolic content of the myrtle fruit and to investigate the differences between the genotypes. Myrtle fruits were collected from Antalya district. Phenolic content was determined by HPLC. Gallic acid (GA, catechin (CT, epicatechin (ECT, epicatechin-3-0-gallate (ECG, procyanidin B1 (B1, procyanidin B2 (B2, quercetin (Q, kamferol (K and myricetin (M were calculated as phenolic compounds. Epicatechin-3-0-gallate (in flavan-3-ol group and myricetin (in flavonol group were detected in large amounts.

Prediction of Protein Thermostability by an Efficient Neural Network Approach

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Jalal Rezaeenour

2016-10-01

Full Text Available Introduction: Manipulation of protein stability is important for understanding the principles that govern protein thermostability, both in basic research and industrial applications. Various data mining techniques exist for prediction of thermostable proteins. Furthermore, ANN methods have attracted significant attention for prediction of thermostability, because they constitute an appropriate approach to mapping the non-linear input-output relationships and massive parallel computing. Method: An Extreme Learning Machine (ELM was applied to estimate thermal behavior of 1289 proteins. In the proposed algorithm, the parameters of ELM were optimized using a Genetic Algorithm (GA, which tuned a set of input variables, hidden layer biases, and input weights, to and enhance the prediction performance. The method was executed on a set of amino acids, yielding a total of 613 protein features. A number of feature selection algorithms were used to build subsets of the features. A total of 1289 protein samples and 613 protein features were calculated from UniProt database to understand features contributing to the enzymes’ thermostability and find out the main features that influence this valuable characteristic. Results:At the primary structure level, Gln, Glu and polar were the features that mostly contributed to protein thermostability. At the secondary structure level, Helix_S, Coil, and charged_Coil were the most important features affecting protein thermostability. These results suggest that the thermostability of proteins is mainly associated with primary structural features of the protein. According to the results, the influence of primary structure on the thermostabilty of a protein was more important than that of the secondary structure. It is shown that prediction accuracy of ELM (mean square error can improve dramatically using GA with error rates RMSE=0.004 and MAPE=0.1003. Conclusion: The proposed approach for forecasting problem

Thermostable Carbonic Anhydrases in Biotechnological Applications

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Anna Di Fiore

2015-07-01

Full Text Available Carbonic anhydrases are ubiquitous metallo-enzymes which catalyze the reversible hydration of carbon dioxide in bicarbonate ions and protons. Recent years have seen an increasing interest in the utilization of these enzymes in CO2 capture and storage processes. However, since this use is greatly limited by the harsh conditions required in these processes, the employment of thermostable enzymes, both those isolated by thermophilic organisms and those obtained by protein engineering techniques, represents an interesting possibility. In this review we will provide an extensive description of the thermostable carbonic anhydrases so far reported and the main processes in which these enzymes have found an application.

Evaluation of Phenolic Content and Antioxidant Capacity of Blueberry Cultivars (Vaccinium corymbosum L. Grown in the Northwest Croatia

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Verica Dragović-Uzelac

2010-01-01

Full Text Available The aim of this study is to evaluate the content of phenolics: total phenols (TPC, flavonoids (TF, anthocyanins (TA, flavan-3-ols (TF3ols, as well as total antioxidant capacity (TAC and reducing power (RP in four blueberry cultivars (Vaccinium corymbosum L. introduced in the Northwest Croatian climate conditions. Phenolic compounds were measured by spectrophotometric methods, TAC was determined using DPPH and ABTS assays and RP by FRAP assay. All cultivars contained high mass fraction of TPC, TF, TA and lower mass fraction of TF3ols. Among the researched fruits, Sierra cultivar contained the highest amounts of all groups of phenolics, followed by Elliott>Bluecrop≥Duke. Significant differences were observed in phenolic mass fraction among different cultivars and growing seasons (p<0.05, and phenolic compounds were significantly higher in growing season 2006. Examined cultivars possess high antioxidant capacity and reducing power, and all phenolics were highly correlated with TAC and RP (R=0.46 to 0.99. The study indicated that growing and climate conditions in Northwest Croatia are convenient for introducing blueberry cultivars. Generally, blueberry fruits are a rich source of phenolics, which show evident antioxidant capacity.

Influences of harvest date and location on the levels of ß-carotene, ascorbic acid, total phenols, in vitro antioxidant capacity, and phenolic profiles of five commercial varieties of mango (Mangifera indica L.)

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Mango (Mangifera indica L.) is a tropical fruit crop grown worldwide with widely attributed nutritional and health-promoting properties. Extensive studies have been made of the high concentrations of phenolic antioxidants in the peel, seeds, and leaves of mango, yet less is known about the phenolic ...

Isolation, chemical characterization, and free radical scavenging activity of phenolics from Triticum aestivum L. aerial parts.

Science.gov (United States)

Kowalska, Iwona; Pecio, Lukasz; Ciesla, Lukasz; Oleszek, Wieslaw; Stochmal, Anna

2014-11-19

Fourteen phenolic compounds (flavonoids and phenolic acids) were isolated and 19 were identified in the aerial parts of Triticum aestivum L. The structures of these compounds were established on the basis of the data obtained by electrospray ionization-mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR) techniques. T. aestivum L. was found to be rich in flavones, especially in luteolin derivatives. Three of the isolated compounds, including luteolin 6-C-[6Glc″-O-E-caffeoyl-β-D-glucopyranosyl(1″→2)-β-glucopyranoside], luteolin 6-C-[5Rib″-O-E-feruoyl-β-D-ribofuranosyl(1″→2)-β-glucopyranoside], and 3',4',5'-O-trimethyltricetin 7-O-[β-D-glucuropyranosyl(1″→2)-β-D-glucopyranoside], have been reported for the first time in the plant kingdom. The amount of individual phenolics, in winter wheat, was also determined. Additionally, the free radical scavenging potential of the isolated compounds was tested in a simple and rapid thin-layer chromatography-2,2-diphenyl-1-picrylhydrazyl radical test (TLC-DPPH•) with image processing.

Eosin-sensitized photooxidation of substituted phenylalanines and tyrosines

Energy Technology Data Exchange (ETDEWEB)

Rizzuto, F.; Spikes, J.D.

1977-01-01

The cosin-sensitized photooxidation of tyrosine and a number of compounds related to tyrosine (substituted phenylalanines) was studied by steady-state kinetic and flash photolysis techniques. In particular, the role of the phenolic group and the amino and carboxyl groups of the alanyl side chain in the photooxidation mechanism was investigated in detail. Several relationships between substrate structure and susceptibility to photooxidation as well as effects of substrate structure on photooxidation mechanisms were found. For example, phenylalanine is not photooxidizable, but substitution of electron-donating (activating) groups such as -OH (as in tyrosine) or -NH/sub 2/ (as in p-aminophenylalanine) results in rapidly photooxidized derivatives. However, substituting deactivating groups such as -Cl (as in p-chlorophenylalanine) or weakly activating groups such as -OCH/sub 3/ (as in 4-methoxyphenylalanine) result in non-photooxidizable derivatives. Substitution of additional activating groups to the ring of hydroxy-substituted phenylalanines results in increased rates of photooxidation, whereas additional deactivating groups result in decreased photooxidation rates. The rate-determining step in the photooxidation mechanism is shown to be dependent on the presence and position of an electron-donating substituent on the benzenoid ring. Only minor involvement of the side chain amino and carboxyl groups was found. Both singlet oxygen and hydrogen abstraction mechanisms are involved in the eosin-sensitized photooxidation of hydroxy-substituted phenylalanines (e.g., tyrosine). The hydrogen abstraction mechanism probably predominates at both pH 8 and 11.

Characterization of AlgMsp, an alginate lyase from Microbulbifer sp. 6532A.

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Steven M Swift

Full Text Available Alginate is a polysaccharide produced by certain seaweeds and bacteria that consists of mannuronic acid and guluronic acid residues. Seaweed alginate is used in food and industrial chemical processes, while the biosynthesis of bacterial alginate is associated with pathogenic Pseudomonas aeruginosa. Alginate lyases cleave this polysaccharide into short oligo-uronates and thus have the potential to be utilized for both industrial and medicinal applications. An alginate lyase gene, algMsp, from Microbulbifer sp. 6532A, was synthesized as an E.coli codon-optimized clone. The resulting 37 kDa recombinant protein, AlgMsp, was expressed, purified and characterized. The alginate lyase displayed highest activity at pH 8 and 0.2 M NaCl. Activity of the alginate lyase was greatest at 50°C; however the enzyme was not stable over time when incubated at 50°C. The alginate lyase was still highly active at 25°C and displayed little or no loss of activity after 24 hours at 25°C. The activity of AlgMsp was not dependent on the presence of divalent cations. Comparing activity of the lyase against polymannuronic acid and polyguluronic acid substrates showed a higher turnover rate for polymannuronic acid. However, AlgMSP exhibited greater catalytic efficiency with the polyguluronic acid substrate. Prolonged AlgMsp-mediated degradation of alginate produced dimer, trimer, tetramer, and pentamer oligo-uronates.

UVA, UVB and UVC Light Enhances the Biosynthesis of Phenolic Antioxidants in Fresh-Cut Carrot through a Synergistic Effect with Wounding

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Bernadeth B. Surjadinata

2017-04-01

Full Text Available Previously, we found that phenolic content and antioxidant capacity (AOX in carrots increased with wounding intensity. It was also reported that UV radiation may trigger the phenylpropanoid metabolism in plant tissues. Here, we determined the combined effect of wounding intensity and UV radiation on phenolic compounds, AOX, and the phenylalanine ammonia-lyase (PAL activity of carrots. Accordingly, phenolic content, AOX, and PAL activity increased in cut carrots with the duration of UVC radiation, whereas whole carrots showed no increase. Carrot pies showed a higher increase compared to slices and shreds. Phenolics, AOX, and PAL activity also increased in cut carrots exposed to UVA or UVB. The major phenolics were chlorogenic acid and its isomers, ferulic acid, and isocoumarin. The type of UV radiation affected phenolic profiles. Chlorogenic acid was induced by all UV radiations but mostly by UVB and UVC, ferulic acid was induced by all UV lights to comparable levels, while isocoumarin and 4,5-diCQA was induced mainly by UVB and UVC compared to UVA. In general, total phenolics correlated linearly with AOX for all treatments. A reactive oxygen species (ROS mediated hypothetical mechanism explaining the synergistic effect of wounding and different UV radiation stresses on phenolics accumulation in plants is herein proposed.

Identification of BCAP-{sub L} as a negative regulator of the TLR signaling-induced production of IL-6 and IL-10 in macrophages by tyrosine phosphoproteomics

Energy Technology Data Exchange (ETDEWEB)

Matsumura, Takayuki [Consolidated Research Institute for Advanced Science and Medical Care, Waseda University, Shinjuku-ku, Tokyo 162-0041 (Japan); Department of Life Science and Medical Bio-Science, Waseda University, Shinjuku-ku, Tokyo 162-8480 (Japan); Oyama, Masaaki; Kozuka-Hata, Hiroko [Medical Proteomics Laboratory, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639 (Japan); Ishikawa, Kosuke; Inoue, Takafumi [Consolidated Research Institute for Advanced Science and Medical Care, Waseda University, Shinjuku-ku, Tokyo 162-0041 (Japan); Department of Life Science and Medical Bio-Science, Waseda University, Shinjuku-ku, Tokyo 162-8480 (Japan); Muta, Tatsushi [Laboratory of Cell Recognition and Response, Graduate School of Life Sciences, Tohoku University, Sendai 980-8578 (Japan); Semba, Kentaro, E-mail: ksemba@waseda.jp [Consolidated Research Institute for Advanced Science and Medical Care, Waseda University, Shinjuku-ku, Tokyo 162-0041 (Japan); Department of Life Science and Medical Bio-Science, Waseda University, Shinjuku-ku, Tokyo 162-8480 (Japan); Inoue, Jun-ichiro, E-mail: jun-i@ims.u-tokyo.ac.jp [Medical Proteomics Laboratory, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639 (Japan); Division of Cellular and Molecular Biology, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639 (Japan)

2010-09-17

Research highlights: {yields} Twenty five tyrosine-phosphorylated proteins in LPS-stimulated macrophages were determined. {yields} BCAP is a novel tyrosine-phosphorylated protein in LPS-stimulated macrophages. {yields} BCAP-{sub L} inhibits IL-6 and IL-10 production in LPS-stimulated macrophages. -- Abstract: Toll-like receptor (TLR) signaling in macrophages is essential for anti-pathogen responses such as cytokine production and antigen presentation. Although numerous reports suggest that protein tyrosine kinases (PTKs) are involved in cytokine induction in response to lipopolysaccharides (LPS; TLR4 ligand) in macrophages, the PTK-mediated signal transduction pathway has yet to be analyzed in detail. Here, we carried out a comprehensive and quantitative dynamic tyrosine phosphoproteomic analysis on the TLR4-mediated host defense system in RAW264.7 macrophages using stable isotope labeling by amino acids in cell culture (SILAC). We determined the temporal profiles of 25 proteins based on SILAC-encoded peptide(s). Of these, we focused on the tyrosine phosphorylation of B-cell adaptor for phosphatidylinositol 3-kinase (BCAP) because the function of BCAP remains unknown in TLR signaling in macrophages. Furthermore, Bcap has two distinct transcripts, a full-length (Bcap-{sub L}) and an alternatively initiated or spliced (Bcap-{sub S}) mRNA, and little is known about the differential functions of the BCAP-{sub L} and BCAP-{sub S} proteins. Our study showed, for the first time, that RNAi-mediated selective depletion of BCAP-{sub L} enhanced IL-6 and IL-10 production but not TNF-{alpha} production in TLR ligand-stimulated macrophages. We propose that BCAP-{sub L} (but not BCAP-{sub S}) is a negative regulator of the TLR-mediated host defense system in macrophages.

Structure and Mechanism of PhnP, a Phosphodiesterase of the Carbon-Phosphorus Lyase Pathway

DEFF Research Database (Denmark)

He, Shu-Mei; Wathier, Matthew; Podzelinska, Kateryna

2011-01-01

PhnP is a phosphodiesterase that plays an important role within the bacterial carbon-phosphorus lyase (CP-lyase) pathway by recycling a "dead-end" intermediate, 5-phospho-α-d-ribosyl 1,2-cyclic phosphate, that is formed during organophosphonate catabolism. As a member of the metallo-β-lactamase s......PhnP is a phosphodiesterase that plays an important role within the bacterial carbon-phosphorus lyase (CP-lyase) pathway by recycling a "dead-end" intermediate, 5-phospho-α-d-ribosyl 1,2-cyclic phosphate, that is formed during organophosphonate catabolism. As a member of the metallo...

Polyphenols and phenolic acids in sweet potato (Ipomoea batatas L. roots

Directory of Open Access Journals (Sweden)

Janette Musilová

2017-01-01

Full Text Available Sweet potato (Ipomoea batatas L. is one of the most important food crops in the world. They are rich in polyphenols, proteins, vitamins, minerals and some functional microcomponents. Polyphenols are bioactive compounds, which can protect the human body from the oxidative stress which may cause many diseases including cancer, aging and cardiovascular problems.The polyphenol content is two to three times higher than in some common vegetables. Total polyphenols (determined spectrophotometrically and phenolic acids (i.e. caffeic acid, chlorogenic acid and isomers - using high performance liquid chromatography contents were determined in three varieties of sweet potatoes (O´Henry - white, Beauregard-orange and 414-purple. Phenolic compounds contents were determined in raw peeled roots, jackets of raw roots and water steamed sweet potato roots. For all analysis lyophilised samples were used. Total polyphenol content ranged from 1161 (O´Henry, flesh-raw to 13998 (414, peel-raw mg.kg-1 dry matter, caffeic acid content from the non-detected values (414, flesh-raw to 320.7 (Beauregard, peel-raw mg.kg-1 dry matter and 3-caffeoylquinic acid content from 57.57 (O´Henry, flesh-raw to 2392 (414, peel-raw mg.kg-1 dry matter. Statistically significant differences (p ≤0.05 existed between varieties, morphological parts of the root, or raw and heat-treated sweet potato in phenolic compounds contents.

One-Pot Enzymatic Synthesis of D-Arylalanines Using Phenylalanine Ammonia Lyase and L-Amino Acid Deaminase.

Science.gov (United States)

Zhu, Longbao; Feng, Guoqiang; Ge, Fei; Song, Ping; Wang, Taotao; Liu, Yi; Tao, Yugui; Zhou, Zhemin

2018-06-08

The phenylalanine ammonia-lyase (AvPAL) from Anabaena variabilis catalyzes the amination of substituent trans-cinnamic acid (t-CA) to produce racemic D,L-enantiomer arylalanine mixture owing to its low stereoselectivity. To produce high optically pure D-arylalanine, a modified AvPAL with high D-selectivity is expected. Based on the analyses of catalytic mechanism and structure, the Asn347 residue in the active site was proposed to control stereoselectivity. Therefore, Asn347 was mutated to construct mutant AvPAL-N347A, the stereoselectivity of AvPAL-N347A for D-enantiomer arylalanine was 2.3-fold higher than that of wild-type AvPAL (WtPAL). Furthermore, the residual L-enantiomer product in reaction solution could be converted into the D-enantiomer product through stereoselective oxidation by PmLAAD and nonselective reduction by reducing agent NH 3 BH 3 . At optimal conditions, the conversion rate of t-CA and optical purity (enantiomeric excess (ee D )) of D-phenylalanine reached 82% and exceeded 99%, respectively. The two enzymes displayed activity toward a broad range of substrate and could be used to efficiently synthesize D-arylalanine with different groups on the phenyl ring. Among these D-arylalanines, the yield of m-nitro-D-phenylalanine was highest and reached 96%, and the ee D exceeded 99%. This one-pot synthesis using AvPAL and PmLAAD has prospects for industrial application.

Thermostable cellulases, and mutants thereof, capable of hydrolyzing cellulose in ionic liquid

Science.gov (United States)

Sapra, Rajat; Datta, Supratim; Chen, Zhiwei; Holmes, Bradley M.; Simmons, Blake A.; Blanch, Harvey W.

2016-04-26

The present invention provides for a composition comprising an ionic liquid and a thermostable cellulose, and a method of hydrolyzing a cellulose, comprising: (a) providing a composition comprising a solution comprising an ionic liquid and a cellulose, and (b) introducing a thermostable cellulase to the solution, such that the cellulose is hydrolyzed by the cellulase. The present invention also provides for a Thermatoga maritima thermostable cellulase mutant with increased cellulase activity.

Prenatal diagnosis in adenylosuccinate lyase deficiency

NARCIS (Netherlands)

Marie, S.; Flipsen, J. W.; Duran, M.; Poll-The, B. T.; Beemer, F. A.; Bosschaart, A. N.; Vincent, M. F.; van den Berghe, G.

2000-01-01

Adenylosuccinate lyase deficiency, an autosomal recessive inborn error of purine synthesis, provokes accumulation in body fluids of succinylaminoimidazolecarboxamide riboside and succinyladenosine, the dephosphorylated derivatives of the two substrates of the enzyme. Most patients display severe

Roles of the tyrosine isomers meta-tyrosine and ortho-tyrosine in oxidative stress.

Science.gov (United States)

Ipson, Brett R; Fisher, Alfred L

2016-05-01

The damage to cellular components by reactive oxygen species, termed oxidative stress, both increases with age and likely contributes to age-related diseases including Alzheimer's disease, atherosclerosis, diabetes, and cataract formation. In the setting of oxidative stress, hydroxyl radicals can oxidize the benzyl ring of the amino acid phenylalanine, which then produces the abnormal tyrosine isomers meta-tyrosine or ortho-tyrosine. While elevations in m-tyrosine and o-tyrosine concentrations have been used as a biological marker of oxidative stress, there is emerging evidence from bacterial, plant, and mammalian studies demonstrating that these isomers, particularly m-tyrosine, directly produce adverse effects to cells and tissues. These new findings suggest that the abnormal tyrosine isomers could in fact represent mediators of the effects of oxidative stress. Consequently the accumulation of m- and o-tyrosine may disrupt cellular homeostasis and contribute to disease pathogenesis, and as result, effective defenses against oxidative stress can encompass not only the elimination of reactive oxygen species but also the metabolism and ultimately the removal of the abnormal tyrosine isomers from the cellular amino acid pool. Future research in this area is needed to clarify the biologic mechanisms by which the tyrosine isomers damage cells and disrupt the function of tissues and organs and to identify the metabolic pathways involved in removing the accumulated isomers after exposure to oxidative stress. Published by Elsevier B.V.

Production and Purification of a Novel Xanthan Lyase from a Xanthan-Degrading Microbacterium sp. Strain XT11

Directory of Open Access Journals (Sweden)

Fan Yang

2014-01-01

Full Text Available A xanthan lyase was produced and purified from the culture supernatant of an excellent xanthan-modifying strain Microbacterium sp. XT11. Xanthan lyase was induced by xanthan but was inhibited by its structural monomer glucose. Its production by strain XT11 is much higher than that by all other reported strains. The purified xanthan lyase has a molecular mass of 110 kDa and a specific activity of 28.2 U/mg that was much higher than that of both Paenibacillus and Bacillus lyases. It was specific on the pyruvated mannosyl residue in the intact xanthan molecule, but about 50% lyase activity remained when xanthan was partially depyruvated. Xanthan lyase was optimally active at pH 6.0–6.5 and 40°C and alkali-tolerant at a high pH value of 11.0. The metal ions including K+, Ca2+, Na+, Mg2+, Mn2+, and Li+ strongly stimulated xanthan lyase activity but ions Zn2+ and Cu2+ were its inhibitor. Xanthan lyase should be a novel enzyme different from the other xanthan lyases ever reported.

Purification and Characterization of a Thermostable Lipase from Geobacillus thermodenitrificans IBRL-nra

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Anuradha Balan

2012-01-01

Full Text Available Thermostable lipase from Geobacillus thermodenitrificans IBRL-nra was purified and characterized. The production of thermostable lipase from Geobacillus thermodenitrificans IBRL-nra was carried out in a shake-flask system at 65°C in cultivation medium containing; glucose 1.0% (w/v; yeast extract 1.25% (w/v; NaCl 0.45% (w/v olive oil 0.1% (v/v with agitation of 200 rpm for 24 hours. The extracted extracellular crude thermostable lipase was purified to homogeneity by using ultrafiltration, Heparin-affinity chromatography, and Sephadex G-100 gel-filtration chromatography by 34 times with a final yield of 9%. The molecular weight of the purified enzyme was estimated to be 30 kDa after SDS-PAGE analysis. The optimal temperature for thermostable lipase was 65°C and it retained its initial activity for 3 hours. Thermostable lipase activity was highest at pH 7.0 and stable for 16 hours at this pH at 65°C. Thermostable lipase showed elevated activity when pretreated with BaCl2, CaCl2, and KCl with 112%, 108%, and 106%, respectively. Lipase hydrolyzed tripalmitin (C16 and olive oil with optimal activity (100% compared to other substrates.

Renal cysteine conjugate C-S lyase mediated toxicity of halogenated alkenes in primary cultures of human and rat proximal tubular cells.

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McGoldrick, Trevor A; Lock, Edward A; Rodilla, Vicente; Hawksworth, Gabrielle M

2003-07-01

Proximal tubular cells from human (HPT) and rat (RPT) kidneys were isolated, grown to confluence and incubated with S-(1,2-dichlorovinyl)- l-cysteine (DCVC), S-(1,2,2-trichlorovinyl)- l-cysteine (TCVC), S-(1,1,2,2-tetrafluoroethyl)- l-cysteine (TFEC) and S-(2-chloro-1,1-difluorethyl)- l-cysteine (CDFEC), the cysteine conjugates of nephrotoxicants. The cultures were exposed to the conjugates for 12, 24 and 48 h and the toxicity determined using the MTT assay. All four conjugates caused dose-dependent toxicity to RPT cells over the range 50-1,000 microM, the order of toxicity being DCVC>TCVC>TFEC=CDFEC. The inclusion of aminooxyacetic acid (AOAA; 250 microM), an inhibitor of pyridoxal phosphate-dependent enzymes such as C-S lyase, afforded protection, indicating that C-S lyase has a role in the bioactivation of these conjugates. In HPT cultures only DCVC caused significant time- and dose-dependent toxicity. Exposure to DCVC (500 microM) for 48 h decreased cell viability to 7% of control cell values, whereas co-incubation of DCVC (500 microM) with AOAA (250 microM) resulted in cell viability of 71%. Human cultures were also exposed to S-(1,2-dichlorovinyl)-glutathione (DCVG). DCVG was toxic to HPT cells, but the onset of toxicity was delayed compared with the corresponding cysteine conjugate. AOAA afforded almost complete protection from DCVG toxicity. Acivicin (250 microM), an inhibitor of gamma-glutamyl transferase (gamma-GT), partially protected against DCVG (500 microM)-induced toxicity at 48 h (5% viability and 53% viability in the absence and presence of acivicin, respectively). These results suggest that DCVG requires processing by gamma-GT prior to bioactivation by C-S lyase in HPT cells. The activity of C-S lyase, using TFEC as a substrate, and glutamine transaminase K (GTK) was measured in rat and human cells with time in culture. C-S lyase activity in RPT and HPT cells decreased to approximately 30% of fresh cell values by the time the cells reached

Human phenylalanine hydroxylase is activated by H2O2: a novel mechanism for increasing the L-tyrosine supply for melanogenesis in melanocytes

International Nuclear Information System (INIS)

Schallreuter, Karin U.; Wazir, Umar; Kothari, Sonal; Gibbons, Nicholas C.J.; Moore, Jeremy; Wood, John M.

2004-01-01

Epidermal phenylalanine hydroxylase (PAH) produces L-tyrosine from the essential amino acid L-phenylalanine supporting melanogenesis in human melanocytes. Those PAH activities increase linearly in the different skin phototypes I-VI (Fitzpatrick classification) and also increase up to 24 h after UVB light with only one minimal erythemal dose. Since UVB generates also H 2 O 2 , we here asked the question whether this reactive oxygen species could influence the activity of pure recombinant human PAH. Under saturating conditions with the substrate L-phenylalanine (1 x 10 -3 M), the V max for enzyme activity increased 4-fold by H 2 O 2 (>2.0 x 10 -3 M). Lineweaver-Burk analysis identified a mixed activation mechanism involving both the regulatory and catalytic domains of PAH. Hyperchem molecular modelling and Deep View analysis support oxidation of the single Trp 120 residue to 5-OH-Trp 120 by H 2 O 2 causing a conformational change in the regulatory domain. PAH was still activated by H 2 O 2 in the presence of the electron donor/cofactor 6(R)-L-erythro-5,6,7,8-tetrahydrobiopterin despite slow oxidation of this cofactor. In vivo FT-Raman spectroscopy confirmed decreased epidermal phenylalanine in association with increased tyrosine after UVB exposure. Hence, generation of H 2 O 2 by UVB can activate epidermal PAH leading to an increased L-tyrosine pool for melanogenesis

New lupane triterpenoids from Solidago canadensis that inhibit the lyase activity of DNA polymerase beta.

Science.gov (United States)

Chaturvedula, V S Prakash; Zhou, Bing-Nan; Gao, Zhijie; Thomas, Shannon J; Hecht, Sidney M; Kingston, David G I

2004-12-01

Bioassay-directed fractionation of a methyl ethyl ketone extract of Solidago canadensis L. (Asteraceae), using an assay to detect the lyase activity of DNA polymerase beta, resulted in the isolation of the four new lupane triterpenoids 1-4 and the seven known compounds lupeol, lupeyl acetate, ursolic acid, cycloartenol, cycloartenyl palmitate, alpha-amyrin acetate, and stigmasterol. The structures of the new compounds were established as 3beta-(3R-acetoxyhexadecanoyloxy)-lup-20(29)-ene (1), 3beta-(3-ketohexadecanoyloxy)-lup-20(29)-ene (2), 3beta-(3R-acetoxyhexadecanoyloxy)-29-nor-lupan-20-one (3), and 3beta-(3-hetohexadecanoyloxy)-29-nor-lupan-20-one (4), respectively, on the basis of extensive 1D and 2D NMR spectroscopic interpretation and chemical modification studies. All 11 compounds were inhibitory to the lyase activity of DNA polymerase beta.

S1P lyase in thymic perivascular spaces promotes egress of mature thymocytes via up-regulation of S1P receptor 1.

Science.gov (United States)

Maeda, Yasuhiro; Yagi, Hideki; Takemoto, Kana; Utsumi, Hiroyuki; Fukunari, Atsushi; Sugahara, Kunio; Masuko, Takashi; Chiba, Kenji

2014-05-01

Sphingosine 1-phosphate (S1P) and S1P receptor 1 (S1P1) play an important role in the egress of mature CD4 or CD8 single-positive (SP) thymocytes from the thymus. Fingolimod hydrochloride (FTY720), an S1P1 functional antagonist, induced significant accumulation of CD62L(high)CD69(low) mature SP thymocytes in the thymic medulla. Immunohistochemical staining using anti-S1P1 antibody revealed that S1P1 is predominantly expressed on thymocytes in the thymic medulla and is strongly down-regulated even at 3h after FTY720 administration. 2-Acetyl-4-tetrahydroxybutylimidazole (THI), an S1P lyase inhibitor, also induced accumulation of mature SP thymocytes in the thymic medulla with an enlargement of the perivascular spaces (PVS). At 6h after THI administration, S1P1-expressing thymocytes reduced partially as if to form clusters and hardly existed in the proximity of CD31-expressing blood vessels in the thymic medulla, suggesting S1P lyase expression in the cells constructing thymic medullary PVS. To determine the cells expressing S1P lyase in the thymus, we newly established a mAb (YK19-2) specific for mouse S1P lyase. Immunohistochemical staining with YK19-2 revealed that S1P lyase is predominantly expressed in non-lymphoid thymic stromal cells in the thymic medulla. In the thymic medullary PVS, S1P lyase was expressed in ER-TR7-positive cells (reticular fibroblasts and pericytes) and CD31-positive vascular endothelial cells. Our findings suggest that S1P lyase expressed in the thymic medullary PVS keeps the tissue S1P concentration low around the vessels and promotes thymic egress via up-regulation of S1P1.

Development of a new paper based nano-biosensor using the co-catalytic effect of tyrosinase from banana peel tissue (Musa Cavendish) and functionalized silica nanoparticles for voltammetric determination of l-tyrosine.

Science.gov (United States)

Rahimi-Mohseni, Mohadeseh; Raoof, Jahan Bakhsh; Ojani, Reza; Aghajanzadeh, Tahereh A; Bagheri Hashkavayi, Ayemeh

2018-07-01

In this paper, a new and facile method for the electrochemical determination of l-tyrosine was designed. First, 3-mercaptopropyl trimethoxysilane-functionalized silica nanoparticles were added to a paper disc. Then, the banana peel tissue and the mediator potassium hexacyanoferrate were dropped onto the paper, respectively. The modified paper disc was placed on the top of the graphite screen printed electrode and electrochemical characterization of this biosensor was studied by cyclic voltammetry and electrochemical impedance spectroscopy methods. The effective parameters like pH, banana peel tissue percentage, and the amount of mediator loading were optimized. l-tyrosine measurements were done by differential pulse voltammetry with a little sample (3 μL) for analysis. The biosensor showed a linear response for l-tyrosine in the wide concentration range of 0.05-600 μM and a low detection limit about 0.02 μM because of the co-catalytic effect of enzyme and nanoparticles. The stability of the biosensor and its selectivity were evaluated. This biosensor was applied for the voltammetric determination of l-tyrosine in the blood plasma sample. The results of the practical application study were comparable with the standard method (HPLC). In conclusion, a simple, inexpensive, rapid, sensitive and selective technique was successfully applied to the l-tyrosine analysis of the little samples. Copyright © 2018 Elsevier B.V. All rights reserved.

Utilization of Aspergillus oryzae to produce pectin lyase from various agro-industrial residues

OpenAIRE

Koser, Safia; Anwar, Zahid; Iqbal, Zafar; Anjum, Awais; Aqil, Tahir; Mehmood, Sajid; Irshad, Muhammad

2014-01-01

The present study was aimed to investigate the culture influence on pectin lyase production potential of fungal strain Aspergillus oryzae. The enzyme profile of A. oryzae showed highest activity of pectin lyase after 3rd day of incubation on lemon peel waste under solid state fermentation conditions. To induce the pectin lyase synthesis capability of A. oryzae at optimal level various culture variables including physical and nutritional parameters were optimized by adopting classical optimiza...

A novel engineered interchain disulfide bond in the constant region enhances the thermostability of adalimumab Fab.

Science.gov (United States)

Nakamura, Hitomi; Oda-Ueda, Naoko; Ueda, Tadashi; Ohkuri, Takatoshi

2018-01-01

We constructed a system for expressing the Fab of the therapeutic human monoclonal antibody adalimumab at a yield of 20 mg/L in the methylotrophic yeast Pichia pastoris. To examine the contribution of interchain disulfide bonds to conformational stability, we prepared adalimumab Fab from which the interchain disulfide bond at the C-terminal region at both the CH 1 and CL domains was deleted by substitution of Cys with Ala (Fab ΔSS ). DSC measurements showed that the Tm values of Fab ΔSS were approximately 5 °C lower than those of wild-type Fab, suggesting that the interchain disulfide bond contributes to conformational thermostability. Using computer simulations, we designed a novel interchain disulfide bond outside the C-terminal region to increase the stability of Fab ΔSS . The resulting Fab (mutSS Fab ΔSS ) had the mutations H:V177C and L:Q160C in Fab ΔSS , confirming the formation of the disulfide bond between CH 1 and CL. The thermostability of mutSS Fab ΔSS was approximately 5 °C higher than that of Fab ΔSS . Therefore, the introduction of the designed interchain disulfide bond enhanced the thermostability of Fab ΔSS and mitigated the destabilization caused by partial reduction of the interchain disulfide bond at the C-terminal region, which occurs in site-specific modification such as PEGylation. Copyright © 2017 Elsevier Inc. All rights reserved.

Extraction and HPLC analysis of phenolic compounds in leaves, stalks, and textile fibers of Urtica dioica L.

Science.gov (United States)

Pinelli, Patrizia; Ieri, Francesca; Vignolini, Pamela; Bacci, Laura; Baronti, Silvia; Romani, Annalisa

2008-10-08

In the present study the phenolic composition of leaves, stalks, and textile fiber extracts from Urtica dioica L. is described. Taking into account the increasing demand for textile products made from natural fibers and the necessity to create sustainable "local" processing chains, an Italian project was funded to evaluate the cultivation of nettle fibers in the region of Tuscany. The leaves of two nettle samples, cultivated and wild (C and W), contain large amounts of chlorogenic and 2- O-caffeoylmalic acid, which represent 71.5 and 76.5% of total phenolics, respectively. Flavonoids are the main class in the stalks: 54.4% of total phenolics in C and 31.2% in W samples. Anthocyanins are second in quantitative importance and are present only in nettle stalks: 28.6% of total phenolics in C and 24.4% in W extracts. Characterization of phenolic compounds in nettle extracts is an important result with regard to the biological properties (antioxidant and antiradical) of these metabolites for their possible applications in various industrial activities, such as food/feed, cosmetics, phytomedicine, and textiles.

Phenolic composition and antioxidant capacity of pomaces from four grape varieties (Vitis vinifera L.).

Science.gov (United States)

de la Cerda-Carrasco, Aarón; López-Solís, Remigio; Nuñez-Kalasic, Hugo; Peña-Neira, Álvaro; Obreque-Slier, Elías

2015-05-01

Phenolic compounds are widely distributed secondary metabolites in plants usually conferring them with unique taste, flavour and health-promoting properties. In fruits of Vitis vinifera L., phenolic composition is highly dependent on grape variety. Differential extraction of these compounds from grapes during winemaking is critically associated with wine quality. By-products of winemaking, such as grape pomace, can contain significant amounts of polyphenols. However, information concerning the varietal effect on wine grape pomace is scarce. In this study, pomaces from Sauvignon Blanc (SB), Chardonnay (CH), Cabernet Sauvignon (CS) and Carménère (CA) grape varieties were characterized spectroscopically and by HPLC-DAD analysis. White grape pomaces (SB and CH) presented higher antioxidant capacities and higher contents of total phenols and total proanthocyanidins compared with red grape pomaces (CS and CA), whereas the latter showed much higher anthocyanin levels and colour intensities. Concentrations of monomeric proanthocyanidins and low-molecular-weight phenols in the four grape pomace varieties were significantly different. Grape pomaces from four varieties showed high but diverse contents of polyphenols and antioxidant capacities. Thus grape pomaces represent an important potential source of polyphenols, which could be useful for nutritional and/or pharmacological purposes. © 2014 Society of Chemical Industry.

Thermostability promotes the cooperative function of split adenylate kinases.

Science.gov (United States)

Nguyen, Peter Q; Liu, Shirley; Thompson, Jeremy C; Silberg, Jonathan J

2008-05-01

Proteins can often be cleaved to create inactive polypeptides that associate into functional complexes through non-covalent interactions, but little is known about what influences the cooperative function of the ensuing protein fragments. Here, we examine whether protein thermostability affects protein fragment complementation by characterizing the function of split adenylate kinases from the mesophile Bacillus subtilis (AKBs) and the hyperthermophile Thermotoga neapolitana (AKTn). Complementation studies revealed that the split AKTn supported the growth of Escherichia coli with a temperature-sensitive AK, but not the fragmented AKBs. However, weak complementation occurred when the AKBs fragments were fused to polypeptides that strongly associate, and this was enhanced by a Q16L mutation that thermostabilizes the full-length protein. To examine how the split AK homologs differ in structure and function, their catalytic activity, zinc content, and circular dichroism spectra were characterized. The reconstituted AKTn had higher levels of zinc, greater secondary structure, and >10(3)-fold more activity than the AKBs pair, albeit 17-fold less active than full-length AKTn. These findings provide evidence that the design of protein fragments that cooperatively function can be improved by choosing proteins with the greatest thermostability for bisection, and they suggest that this arises because hyperthermophilic protein fragments exhibit greater residual structure compared to their mesophilic counterparts.

Thermostability of biological systems: fundamentals, challenges, and quantification.

Science.gov (United States)

He, Xiaoming

2011-01-01

This review examines the fundamentals and challenges in engineering/understanding the thermostability of biological systems over a wide temperature range (from the cryogenic to hyperthermic regimen). Applications of the bio-thermostability engineering to either destroy unwanted or stabilize useful biologicals for the treatment of diseases in modern medicine are first introduced. Studies on the biological responses to cryogenic and hyperthermic temperatures for the various applications are reviewed to understand the mechanism of thermal (both cryo and hyperthermic) injury and its quantification at the molecular, cellular and tissue/organ levels. Methods for quantifying the thermophysical processes of the various applications are then summarized accounting for the effect of blood perfusion, metabolism, water transport across cell plasma membrane, and phase transition (both equilibrium and non-equilibrium such as ice formation and glass transition) of water. The review concludes with a summary of the status quo and future perspectives in engineering the thermostability of biological systems.

Physiological and functional diversity of phenol degraders isolated from phenol-grown aerobic granules: Phenol degradation kinetics and trichloroethylene co-metabolic activities.

Science.gov (United States)

Zhang, Yi; Tay, Joo Hwa

2016-03-15

Aerobic granule is a novel form of microbial aggregate capable of degrading toxic and recalcitrant substances. Aerobic granules have been formed on phenol as the growth substrate, and used to co-metabolically degrade trichloroethylene (TCE), a synthetic solvent not supporting aerobic microbial growth. Granule formation process, rate limiting factors and the comprehensive toxic effects of phenol and TCE had been systematically studied. To further explore their potential at the level of microbial population and functions, phenol degraders were isolated and purified from mature granules in this study. Phenol and TCE degradation kinetics of 15 strains were determined, together with their TCE transformation capacities and other physiological characteristics. Isolation in the presence of phenol and TCE exerted stress on microbial populations, but the procedure was able to preserve their diversity. Wide variation was found with the isolates' kinetic behaviors, with the parameters often spanning 3 orders of magnitude. Haldane kinetics described phenol degradation well, and the isolates exhibited actual maximum phenol-dependent oxygen utilization rates of 9-449 mg DO g DW(-1) h(-1), in phenol concentration range of 4.8-406 mg L(-1). Both Michaelis-Menten and Haldane types were observed for TCE transformation, with the actual maximum rate of 1.04-21.1 mg TCE g DW(-1) h(-1) occurring between TCE concentrations of 0.42-4.90 mg L(-1). The TCE transformation capacities and growth yields on phenol ranged from 20-115 mg TCE g DW(-1) and 0.46-1.22 g DW g phenol(-1), respectively, resulting in TCE transformation yields of 10-70 mg TCE g phenol(-1). Contact angles of the isolates were between 34° and 82°, suggesting both hydrophobic and hydrophilic cell surface. The diversity in the isolates is a great advantage, as it enables granules to be versatile and adaptive under different operational conditions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Site-directed Mutagenesis Switching a Dimethylallyl Tryptophan Synthase to a Specific Tyrosine C3-Prenylating Enzyme*

Science.gov (United States)

Fan, Aili; Zocher, Georg; Stec, Edyta; Stehle, Thilo; Li, Shu-Ming

2015-01-01

The tryptophan prenyltransferases FgaPT2 and 7-DMATS (7-dimethylallyl tryptophan synthase) from Aspergillus fumigatus catalyze C4- and C7-prenylation of the indole ring, respectively. 7-DMATS was found to accept l-tyrosine as substrate as well and converted it to an O-prenylated derivative. An acceptance of l-tyrosine by FgaPT2 was also observed in this study. Interestingly, isolation and structure elucidation revealed the identification of a C3-prenylated l-tyrosine as enzyme product. Molecular modeling and site-directed mutagenesis led to creation of a mutant FgaPT2_K174F, which showed much higher specificity toward l-tyrosine than l-tryptophan. Its catalytic efficiency toward l-tyrosine was found to be 4.9-fold in comparison with that of non-mutated FgaPT2, whereas the activity toward l-tryptophan was less than 0.4% of that of the wild-type. To the best of our knowledge, this is the first report on an enzymatic C-prenylation of l-tyrosine as free amino acid and altering the substrate preference of a prenyltransferase by mutagenesis. PMID:25477507

[F-18]fluoro-meta-L-tyrosine is a better PET tracer than [F-18]fluoro-L-dopa for the delineation of dopaminergic structures in the human brain

International Nuclear Information System (INIS)

Firnau, G.; Chirakal, R.; Nahmias, C.; Garnett, E.S.

1990-01-01

Fluorine-18 labelled fluoro-m-L-tyrosine (FmLtyr) and fluoro-L-Dopa (F-Dopa) have been synthesized, and the utility of FmLtyr for PET investigations of dopaminergic brain regions has been compared to that of F-dopa. Experimental results from both monkey and human studies indicate that FmLtyr gives better delineation of striatum, and is a better PET tracer than F-dopa

Glycosylation of phenolic compounds by the site-mutated β-galactosidase from Lactobacillus bulgaricus L3.

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Lu, Lili; Xu, Lijuan; Guo, Yuchuan; Zhang, Dayu; Qi, Tingting; Jin, Lan; Gu, Guofeng; Xu, Li; Xiao, Min

2015-01-01

β-Galactosidases can transfer the galactosyl from lactose or galactoside donors to various acceptors and thus are especially useful for the synthesis of important glycosides. However, these enzymes have limitations in the glycosylation of phenolic compounds that have many physiological functions. In this work, the β-galactosidase from Lactobacillus bulgaricus L3 was subjected to site-saturation mutagenesis at the W980 residue. The recombinant pET-21b plasmid carrying the enzyme gene was used as the template for mutation. The mutant plasmids were transformed into Escherichia coli cells for screening. One recombinant mutant, W980F, exhibited increased yield of glycoside when using hydroquinone as the screening acceptor. The enzyme was purified and the effects of the mutation on enzyme properties were determined in detail. It showed improved transglycosylation activity on novel phenolic acceptors besides hydroquinone. The yields of the glycosides produced from phenol, hydroquinone, and catechol were increased by 7.6% to 53.1%. Moreover, it generated 32.3% glycosides from the pyrogallol that could not be glycosylated by the wild-type enzyme. Chemical structures of these glycoside products were further determined by MS and NMR analysis. Thus, a series of novel phenolic galactosides were achieved by β-galactosidase for the first time. This was a breakthrough in the enzymatic galactosylation of the challenging phenolic compounds of great values.

Glycosylation of phenolic compounds by the site-mutated β-galactosidase from Lactobacillus bulgaricus L3.

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Lili Lu

Full Text Available β-Galactosidases can transfer the galactosyl from lactose or galactoside donors to various acceptors and thus are especially useful for the synthesis of important glycosides. However, these enzymes have limitations in the glycosylation of phenolic compounds that have many physiological functions. In this work, the β-galactosidase from Lactobacillus bulgaricus L3 was subjected to site-saturation mutagenesis at the W980 residue. The recombinant pET-21b plasmid carrying the enzyme gene was used as the template for mutation. The mutant plasmids were transformed into Escherichia coli cells for screening. One recombinant mutant, W980F, exhibited increased yield of glycoside when using hydroquinone as the screening acceptor. The enzyme was purified and the effects of the mutation on enzyme properties were determined in detail. It showed improved transglycosylation activity on novel phenolic acceptors besides hydroquinone. The yields of the glycosides produced from phenol, hydroquinone, and catechol were increased by 7.6% to 53.1%. Moreover, it generated 32.3% glycosides from the pyrogallol that could not be glycosylated by the wild-type enzyme. Chemical structures of these glycoside products were further determined by MS and NMR analysis. Thus, a series of novel phenolic galactosides were achieved by β-galactosidase for the first time. This was a breakthrough in the enzymatic galactosylation of the challenging phenolic compounds of great values.

Plant growth and phenolic compounds in the rhizosphere soil of wild oat (Avena fatua L.

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Anna eIannucci

2013-12-01

Full Text Available The objectives of this study were to determine the pattern of dry matter (DM accumulation and the evolution of phenolic compounds in the rhizosphere soil from tillering to the ripe seed stages of wild oat (Avena fatua L., a widespread annual grassy weed. Plants were grown under controlled conditions and harvested 13 times during the growing season. At each harvest, shoot and root DM and phenolic compounds in the rhizosphere soil were determined. The maximum DM production (12.6 g/plant was recorded at 122 days after sowing (DAS; kernel hard stage. The increase in total aerial DM with age coincided with reductions in the leaf/stem and source/sink ratios, and an increase in the shoot/root ratio. HPLC analysis shows production of seven phenolic compounds in the rhizosphere soil of wild oat, in order of their decreasing levels: syringic acid, vanillin, 4-hydroxybenzoic acid, syringaldehyde, ferulic acid, p-cumaric acid and vanillic acid. The seasonal distribution for the total phenolic compounds showed two peaks of maximum concentrations, at the stem elongation stage (0.71 μg/kg; 82 DAS and at the heading stage (0.70 μg/kg; 98 DAS. Thus wild oat roots exude allelopathic compounds, and the levels of these phenolics in the rhizosphere soil vary according to plant maturity.

The intensity of tyrosine nitration is associated with selenite and selenate toxicity in Brassica juncea L.

Science.gov (United States)

Molnár, Árpád; Feigl, Gábor; Trifán, Vanda; Ördög, Attila; Szőllősi, Réka; Erdei, László; Kolbert, Zsuzsanna

2018-01-01

Selenium phytotoxicity involves processes like reactive nitrogen species overproduction and nitrosative protein modifications. This study evaluates the toxicity of two selenium forms (selenite and selenate at 0µM, 20µM, 50µM and 100µM concentrations) and its correlation with protein tyrosine nitration in the organs of hydroponically grown Indian mustard (Brassica juncea L.). Selenate treatment resulted in large selenium accumulation in both Brassica organs, while selenite showed slight root-to-shoot translocation resulting in a much lower selenium accumulation in the shoot. Shoot and root growth inhibition and cell viability loss revealed that Brassica tolerates selenate better than selenite. Results also show that relative high amounts of selenium are able to accumulate in Brassica leaves without obvious visible symptoms such as chlorosis or necrosis. The more severe phytotoxicity of selenite was accompanied by more intense protein tyrosine nitration as well as alterations in nitration pattern suggesting a correlation between the degree of Se forms-induced toxicities and nitroproteome size, composition in Brassica organs. These results imply the possibility of considering protein tyrosine nitration as novel biomarker of selenium phytotoxicity, which could help the evaluation of asymptomatic selenium stress of plants. Copyright © 2017 Elsevier Inc. All rights reserved.

Chemical composition and antioxidant activity of phenolic compounds and essential oils from Calamintha nepeta L.

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Khodja, Nabyla Khaled; Boulekbache, Lila; Chegdani, Fatima; Dahmani, Karima; Bennis, Faiza; Madani, Khodir

2018-05-24

Background Essential oils, infusion and decoction extracts of Calamintha nepeta L. were evaluated for their bioactive substances (polyphenols and essential oils) and antioxidant activities. Methods The amounts of phenolic compounds were determined by colorimetric assays and identified by high performance and liquid chromatography coupled with ultraviolet detector (HPLC-UV) method. The chemical composition of essential oils was determined by gas-chromatography coupled with mass spectrometry (GC/MS) method. For the evaluation of the antioxidant activity of essential oils and extracts, two different assays (reducing power and DPPH radical scavenging activity) were used. Results Infusion extract presented the highest phenolic content, followed by the decoction one, while the lowest amount was observed in essential oils. The amount of flavonoids of the decocted extract was higher than that of the infused one. The phenolic profile of C. nepeta infusion and decoction extracts revealed the presence of 28 and 13 peaks, respectively. Four phenolics compounds were identified in infusion (gallic acid (GA), rosmarinic acid (RA), caffeine (C) and caffeic acid (CA)) and two were identified in decoction (GA and RA). The chemical composition of essential oils revealed the presence of 29 compounds, accounting for the 99.7% of the total oils. Major compounds of essential oil (EO) were trans-menthone (50.06%) and pulegone (33.46%). Infusion and decoction extracts revealed an interesting antioxidant activity which correlates positively with their total phenolic contents. Conclusions These results showed that Calamintha nepeta could be considered as a valuable source of phenolics and essential oils with potent antioxidant activity.

123I-Iodomethyl tyrosine radiochemical synthesis and quantification of residual impurities after SepPak purification

International Nuclear Information System (INIS)

Matte, G.; Abrams, D.; Kumar, P.; Mercer, J.

2002-01-01

[123-I]-Iodomethyl tyrosine, an analog of tyrosine, is used as a radiopharmaceutical to detect malignant tissue in vivo. Initial synthesis report removal of the starting material using HPLC reversed phase chromatography as well as a simple method using a C18-SepPak cartridge when an HPLC system is not available. Small amounts of residual starting material have not been reported to interfere with tumor uptake following biodistribution in vivo. However, in vitro tissue culture studies do require the final product to be free of un-reacted methyl tyrosine. Our goal was to quantify the amount of residual methyl tyrosine after C18-SepPak purification to confirm that 123 I methyl tyrosine purified in this manner would be suitable tissue culture studies. A preconditioned (rinsed with 2 ml Ethanol and 8 ml PBS) C18-SepPak cartridge is loaded with the 123 I-iodomethyl tyrosine reaction mixture and washed with 8 mL of PBS to remove the un-reacted methyl tyrosine and free 123 I-iodide. The cartridge is then eluted with a 20% alcohol/PBS mixture to recover the 123 I-iodomethyl tyrosine. Paper chromatography confirmed the removal of un-reacted 123 I-iodide. A parallel study with a methyl tyrosine standard was used to confirm the removal of the methyl tyrosine from the SepPak cartridge during the washing with 8 mL of PBS. Fractions were collected and UV absorbance was recorded. A standard curve was prepared using the UV absorbance of serial dilutions of methyl tyrosine. The detection limit was in the order of ng/mL. An elution profile of both 123 I methyl tyrosine and methyl tyrosine was obtained and shows that traces of methyl tyrosine can still be present after an 8 mL PBS wash

Profiling of phenolic compounds and antioxidant properties of European varieties and cultivars of Vicia faba L. pods.

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Valente, Inês M; Maia, Margarida R G; Malushi, Nertila; Oliveira, Hugo M; Papa, Lumturi; Rodrigues, José A; Fonseca, António J M; Cabrita, Ana R J

2018-08-01

Vicia faba L. pods are a by-product generated from the industrial processing of beans for human and animal consumption. As phenolic compounds may play important roles in health, the present work envisaged the phenolic characterization of seven European varieties and cultivars of V. faba (major and minor) pods and the assessment of their antioxidant activity. The V. faba methanolic extracts were characterized by HPLC-DAD-MS/MS for identification of polyphenolic compounds. The total phenolic content and antioxidant capacity of the extracts were evaluated by colorimetric methods (Folin-Ciocalteu, DPPH scavenging capacity assay, and FRAP assay). Main compounds identified by HPLC-DAD-MS/MS were derivatives of caffeic acid, coumaric acid and kaempferol. The broad bean Jögeva variety presented the highest content of free and esterified phenolics (26.3 and 26.7 mg 100 g -1 dry weight, respectively), followed by the horse bean varieties Bauska and Lielplatones. These results were corroborated by the analysis of total phenolic content, DPPH scavenging capacity and FRAP. This study confirmed the rich phenolic content of V. faba pods suggesting to be an interesting novel source for animal nutrition, promoting product quality and consumers' health. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effects of Mutations and Ligands on the Thermostability of the l-Arginine/Agmatine Antiporter AdiC and Deduced Insights into Ligand-Binding of Human l-Type Amino Acid Transporters

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Hüseyin Ilgü

2018-03-01

Full Text Available The l-arginine/agmatine transporter AdiC is a prokaryotic member of the SLC7 family, which enables pathogenic enterobacteria to survive the extremely acidic gastric environment. Wild-type AdiC from Escherichia coli, as well as its previously reported point mutants N22A and S26A, were overexpressed homologously and purified to homogeneity. A size-exclusion chromatography-based thermostability assay was used to determine the melting temperatures (Tms of the purified AdiC variants in the absence and presence of the selected ligands l-arginine (Arg, agmatine, l-arginine methyl ester, and l-arginine amide. The resulting Tms indicated stabilization of AdiC variants upon ligand binding, in which Tms and ligand binding affinities correlated positively. Considering results from this and previous studies, we revisited the role of AdiC residue S26 in Arg binding and proposed interactions of the α-carboxylate group of Arg exclusively with amide groups of the AdiC backbone. In the context of substrate binding in the human SLC7 family member l-type amino acid transporter-1 (LAT1; SLC7A5, an analogous role of S66 in LAT1 to S26 in AdiC is discussed based on homology modeling and amino acid sequence analysis. Finally, we propose a binding mechanism for l-amino acid substrates to LATs from the SLC7 family.

A novel gene encoding xanthan lyase of Paenibacillus alginolyticus strain XL-1

NARCIS (Netherlands)

Ruijssenaars, H.J.; Hartmans, S.; Verdoes, J.C.

2000-01-01

Xanthan-modifying enzymes are powerful tools in studying structure-function relationships of this polysaccharide. One of these modifying enzymes is xanthan lyase, which removes the terminal side chain residue of xanthan. In this paper, the cloning and sequencing of the first xanthan lyase-encoding

A simple and sensitive fluorescent sensor for methyl parathion based on L-tyrosine methyl ester functionalized carbon dots.

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Hou, Juying; Dong, Jing; Zhu, Haishuang; Teng, Xue; Ai, Shiyun; Mang, Minglin

2015-06-15

In this paper, a simple and sensitive fluorescent sensor for methyl parathion is developed based on L-tyrosine methyl ester functionalized carbon dots (Tyr-CDs) and tyrosinase system. The carbon dots are obtained by simple hydrothermal reaction using citric acid as carbon resource and L-tyrosine methyl ester as modification reagent. The carbon dots are characterized by transmission electron microscope, high resolution transmission electron microscopy, X-ray diffraction spectrum, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The carbon dots show strong and stable photoluminescence with a quantum yield of 3.8%. Tyrosinase can catalyze the oxidation of tyrosine methyl ester on the surface of carbon dots to corresponding quinone products, which can quench the fluorescence of carbon dots. When organophosphorus pesticides (OPs) are introduced in system, they can decrease the enzyme activity, thus decrease the fluorescence quenching rate. Methyl parathion, as a model of OPs, was detected. Experimental results show that the enzyme inhibition rate is proportional to the logarithm of the methyl parathion concentration in the range 1.0×10(-10)-1.0×10(-4) M with the detection limit (S/N=3) of 4.8×10(-11) M. This determination method shows a low detection limit, wide linear range, good selectivity and high reproducibility. This sensing system has been successfully used for the analysis of cabbage, milk and fruit juice samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Characterization and quantification of phenolic compounds in four tomato (Lycopersicon esculentum L.) farmers' varieties in northeastern Portugal homegardens.

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Barros, Lillian; Dueñas, Montserrat; Pinela, José; Carvalho, Ana Maria; Buelga, Celestino Santos; Ferreira, Isabel C F R

2012-09-01

Tomato (Lycopersicon esculentum L.) is one of the most widely consumed fresh and processed vegetables in the world, and contains bioactive key components. Phenolic compounds are one of those components and, according to the present study, farmers' varieties of tomato cultivated in homegardens from the northeastern Portuguese region are a source of phenolic compounds, mainly phenolic acid derivatives. Using HPLC-DAD-ESI/MS, it was concluded that a cis p-coumaric acid derivative was the most abundant compound in yellow (Amarelo) and round (Batateiro) tomato varieties, while 4-O-caffeolyquinic acid was the most abundant in long (Comprido) and heart (Coração) varieties. The most abundant flavonoid was quercetin pentosylrutinoside in the four tomato varieties. Yellow tomato presented the highest levels of phenolic compounds (54.23 μg/g fw), including phenolic acids (43.30 μg/g fw) and flavonoids (10.93 μg/g fw). The phenolic compounds profile obtained for the studied varieties is different from other tomato varieties available in different countries, which is certainly related to genetic features, cultivation conditions, and handling and storage methods associated to each sample.

Euglena mitochondria and chloroplasts form tyrosine-O-sulfate

Energy Technology Data Exchange (ETDEWEB)

Saidha, T.; Hanfstingl, U.; Schiff, J.A. (Brandeis Univ., Waltham, MA (USA))

1989-04-01

Mitochondria from light-grown wild-type Euglena gracilis var. bacillaris Cori or dark-grown mutant W{sub 10}BSmL incubated with {sup 35}SO{sub 4}{sup 2{minus}} and ATP, or with {sup 14}C-tyrosine, non-radioactive sulfate and ATP accumulate a labeled compound in the medium. Since this compound shows exact coelectrophoresis with tyrosine-O-sulfate (TOS) at pH 2.0, 5.8 or 8.0., yields sulfate and tyrosine on acid hydrolysis, and treatment with aryl sulfatase from Aerobacter aerogenes yields sulfate and tyrosine but no tyrosine methyl ester, it is identified as TOS. No TOS is found outside purified developing chloroplasts incubated with {sup 35}SO{sub 4}{sup 2{minus}} and ATP, but both chloroplasts and mitochondria form to {sup 35}S externally when incubated with adenosine 3{prime} phosphate 5{prime}phospho({sup 35}S) sulfate (PAP{sup 35}S). Since no tyrosine need be added, tyrosine is provided from endogenous sources. Although TOS is found in the free pool of Euglena cells it cannot be detected in proteins of cells or mucus ruling our sulfation of tyrosine of protein or incorporation of TOS into proteins. The system forming TOS is membrane-bound and may be involved in tyrosine transport.

Cytochrome c and c1 heme lyases are essential in Plasmodium berghei.

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Posayapisit, Navaporn; Songsungthong, Warangkhana; Koonyosying, Pongpisid; Falade, Mofolusho O; Uthaipibull, Chairat; Yuthavong, Yongyuth; Shaw, Philip J; Kamchonwongpaisan, Sumalee

Malaria parasites possess a de novo heme synthetic pathway. Interestingly, this pathway is dispensable during the blood stages of development in mammalian hosts. The assembly of the two most important hemeproteins, cytochromes c and c1, is mediated by cytochrome heme lyase enzymes. Plasmodium spp. possess two cytochrome heme lyases encoded by separate genes. Given the redundancy of heme synthesis, we sought to determine if heme lyase function also exhibits redundancy. To answer this question, we performed gene knockout experiments. We found that the PBANKA_143950 and PBANKA_0602600 Plasmodium berghei genes encoding cytochrome c (Pbcchl) and cytochrome c1 (Pbcc 1 hl) heme lyases, respectively, can only be disrupted when a complementary gene is present. In contrast, four genes in the de novo heme synthesis pathway can be disrupted without complementation. This work provides evidence that Pbcchl and Pbcc 1 hl are both essential and thus may be antimalarial targets. Copyright © 2016 Elsevier B.V. All rights reserved.

Spectroscopic analyses on interaction of o-Vanillin- D-Phenylalanine, o-Vanillin- L-Tyrosine and o-Vanillin- L-Levodopa Schiff Bases with bovine serum albumin (BSA)

Science.gov (United States)

Gao, Jingqun; Guo, Yuwei; Wang, Jun; Wang, Zhiqiu; Jin, Xudong; Cheng, Chunping; Li, Ying; Li, Kai

2011-04-01

In this work, three o-Vanillin Schiff Bases (o-VSB: o-Vanillin- D-Phenylalanine (o-VDP), o-Vanillin- L-Tyrosine (o-VLT) and o-Vanillin- L-Levodopa (o-VLL)) with alanine constituent were synthesized by direct reflux method in ethanol solution, and then were used to study the interaction to bovine serum albumin (BSA) molecules by fluorescence spectroscopy. Based on the fluorescence quenching calculation, the bimolecular quenching constant ( Kq), apparent quenching constant ( Ksv), effective binding constant ( KA) and corresponding dissociation constant ( KD) as well as binding site number ( n) were obtained. In addition, the binding distance ( r) was also calculated according to Foster's non-radioactive energy transfer theory. The results show that these three o-VSB can efficiently bind to BSA molecules, but the binding array order is o-VDP-BSA > o-VLT-BSA > o-VLL-BSA. Synchronous fluorescence spectroscopy indicates that the o-VDP is more accessibility to tryptophan (Trp) residues of BSA molecules than to tyrosine (Tyr) residues. Nevertheless, the o-VLT and o-VLL are more accessibility to Tyr residues than to Trp residues.

Study on the presence and influence of phenolic compounds in callogenesis and somatic embryo development of cocoa (Theobroma cacao L..

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Sulistyani Pancaningtyas

2015-03-01

Full Text Available Cocoa (Theobroma cacao L. like most tropical trees is recalcitrant in tissue culture. Somatic embryogenesis is generally efficient micropropagation technique to multiply elite material. However, Somatic embryogenesis in cocoa is difficult and this species is considered as recalcitrant. One of the factors often considered as a component of in vitro recalsitrance is a high phenolic content and oxidation of these compounds. In cocoa tissue culture accumulate large amounts of poliphenolics compounds which probably impair further development. This study was conducted to investigate the composition of phenolic compounds in cocoa flower and leaves, and their changes troughout the somatic embryogenesis process. Calli were induced in cacao floral and leaves explants on a half-strenght Murashige and Skoog medium containing 30 g/L Glucose and combination of 2,4 dichlorophenoxyacetic acid (2,4 D with kinetin (kin. Total polyphenol content was observed on Sulawesi 1 cocoa clone. Embryogenic and non-embryogenic callus were also compared. The percentage of callus production from flower tissue is 85%, percentage of embryogenic callus 40 %, although  the percentage of somatic embryo production from embryogenic callus callus is 70%. The conservation of callus into somatic embryos followed by decline in phenol content and an increase in peroxidase. The synthesis kinetics for these compounds in calli, under different somatic embryogenesis conditions, revealed a higher concentration under non-embryogenic conditions. So that, phenolic compound can influence the production of calli and an absence the phenolic compound can enhance production of somatic embryo.Kata kunci: Theobroma cacao L., polifenol, embrio somatik, kalus, flavonoid, katekin, in vitro recalcitance

Developmental role of phenylalanine-ammonia-lyase (PAL) and cinnamate 4-hydroxylase (C4H) genes during adventitious rooting of Juglans regia L. microshoots.

Science.gov (United States)

Cheniany, Monireh; Ganjeali, Ali

2016-12-01

Phenylalanine-ammonia-lyase and cinnamate-4-hydroxylase play important role in the phenylpropanoid pathway, which produces many biologically important secondary metabolites participating in normal plant development. Flavonol quercetin is the main representant of these compounds that has been identified in numerous Juglans spp. In this survey, the developmental expression patterns of PAL and C4H genes during in vitro rooting of two walnut cultivars 'Sunland' and 'Howard' was examined by RT-PCR. To understand the potential role in rooting, the changing pattern of endogenous content of quercetin was also analyzed by HPLC. The 'Sunland' with better capacity to root had more quercetin content during the "inductive phase" of rooting than 'Howard'. In each cultivar, the level of PAL transcripts showed the same behavior with the changing patterns of quercetin during root formation of microshoots. The positive correlation between the changes of quercetin and PAL-mRNA indicated that PAL gene may have an immediate effect on flavonoid pathway metabolites including quercetin. Although the behavioral change of C4H expression was similar in both cultivars during root formation (with significantly more level for 'Howard'), it was not coincide with the changes of quercerin concentrations. Our results showed that C4H function is important for the normal development, but its transcriptional regulation does not correlate with quercetin as an efficient phenolic compound for walnut rhizogenesis.

Methyl jasmonate affects phenolic metabolism and gene expression in blueberry (Vaccinium corymbosum).

Science.gov (United States)

Cocetta, Giacomo; Rossoni, Mara; Gardana, Claudio; Mignani, Ilaria; Ferrante, Antonio; Spinardi, Anna

2015-02-01

Blueberry (Vaccinium corymbosum) is a fruit very much appreciated by consumers for its antioxidant potential and health-promoting traits. Its beneficial potential properties are mainly due to a high content of anthocyanins and their amount can change after elicitation with methyl jasmonate. The aim of this work is to evaluate the changes in expression of several genes, accumulation of phenolic compounds and alterations in antioxidant potential in two different blueberry cultivars ('Duke' and 'Blueray') in response to methyl jasmonate (0.1 mM). Results showed that 9 h after treatment, the expression of phenylalanine ammonium lyase, chalcone synthase and anthocyanidin synthase genes was stimulated more in the 'Blueray' variety. Among the phenols measured an increase was recorded also for epicatechin and anthocyanin concentrations. 'Duke' is a richer sourche of anthocyanins compared to 'Blueray', treatment with methyl jasmonate promoted in 'Blueray' an increase in pigments as well as in the antioxidant potential, especially in fully ripe berries, but treated 'Duke' berries had greater levels, which were not induced by methyl jasmonate treatment. In conclusion, methyl jasmonate was, in some cases, an effective elicitor of phenolic metabolism and gene expression in blueberry, though with different intensity between cultivars. © 2014 Scandinavian Plant Physiology Society.

Uptake of 3-[125I]iodo-α-methyl-L-tyrosine into colon cancer DLD-1 cells: characterization and inhibitory effect of natural amino acids and amino acid-like drugs

International Nuclear Information System (INIS)

Shikano, Naoto; Ogura, Masato; Okudaira, Hiroyuki; Nakajima, Syuichi; Kotani, Takashi; Kobayashi, Masato; Nakazawa, Shinya; Baba, Takeshi; Yamaguchi, Naoto; Kubota, Nobuo; Iwamura, Yukio; Kawai, Keiichi

2010-01-01

Introduction: We examined 3-[ 123 I]iodo-α-methyl-L-tyrosine ([ 123 I]IMT) uptake and inhibition by amino acids and amino acid-like drugs in the human DLD-1 colon cancer cell line, to discuss correlation between the inhibition effect and structure. Methods: Expression of relevant neutral amino acid transporters was examined by real-time PCR with DLD-1 cells. The time course of [ 125 I]IMT uptake, contributions of transport systems, concentration dependence and inhibition effects by amino acids and amino acid-like drugs (1 mM) on [ 125 I]IMT uptake were examined. Results: Expression of system L (4F2hc, LAT1 and LAT2), system A (ATA1, ATA2) and system ASC (ASCT1) was strongly detected; system L (LAT3, LAT4) and MCT8 were weakly detected; and B 0 AT was not detected. [ 125 I]IMT uptake in DLD-1 cells involved Na + -independent system L primarily and Na + -dependent system(s). Uptake of [ 125 I]IMT in Na + -free buffer followed Michaelis-Menten kinetics, with a K m of 78 μM and V max of 333 pmol/10 6 cells per minute. Neutral D- and L-amino acids with branched or aromatic large side chains inhibited [ 125 I]IMT uptake. Tyrosine analogues, tryptophan analogues, L-phenylalanine and p-halogeno-L-phenylalanines, and gamma amino acids [including 3,4-dihydroxy-L-phenylalanine (L-DOPA), DL-threo-β-(3,4-dihydroxyphenyl)serine (DOPS), 4-[bis(2-chloroethyl)amino]-L-phenylalanine and 1-(aminomethyl)-cyclohexaneacetic acid] strongly inhibited [ 125 I]IMT uptake, but L-tyrosine methyl ester and R(+)/S(-)-baclofen weakly inhibited uptake. The substrates of system ASC and A did not inhibit [ 125 I]IMT uptake except L-serine and D/L-cysteine. Conclusions: [ 125 I]IMT uptake in DLD-1 cells involves mostly LAT1 and its substrates' (including amino acid-like drugs derived from tyrosine, tryptophan and phenylalanine) affinity to transport via LAT1. Whether transport of gamma amino acid analogues is involved in LAT1 depends on the structure of the group corresponding to the amino acid

Shade and Drought Stress-Induced Changes in Phenolic Content of Wild Oat (Avena fatua L. Seeds

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Gallagher Robert S.

2010-11-01

Full Text Available Plants develop under a wide range of maternal environments, depending on the time of emergence, prevailing competition from other plants, and presence or absence of other biotic or abiotic stress factors. Stress factors, such as light limitation and drought, during plant development typically reduces the reproductive allocation to seeds, resulting in fewer and often smaller seeds. Such stress factors may also influence seed quality traits associated with persistence in the soil, such as seed dormancy and chemical defense. For this research, we hypothesized that light limitation and drought during wild oat (Avena fatua L. seed development would result in reduced allocation to seed phenolics and other aliphatic organic acids previously identified in the seeds of this species. Wild oat isolines (M73 and SH430 were grown in the greenhouse under cyclic drought conditions (2005 only or two levels of shade (50 and 70%; 2005 and 2006 achieved with standard black shade cloth. The soluble and cellular bound chemical constituents were identified and quantified using gas chromatography - mass spectrometry. The shade and drought stress treatments often significantly affected the mass of the caryopsis and hull seed fractions, as well as the phenolic content of these seed fractions, depending upon isoline, seed fraction, phenolic fraction, and specific phenolics analyzed. Phenolic content of the hull was reduced by the stress environments by up to 48%, whereas there was some evidence of an increase in the soluble phenolic content of the caryopsis in response to the stress environments. Ferulic and p-coumaric acids were the most abundant phenolic acids in both soluble and bound fractions, and bound phenolics comprised generally 95% or more of total phenolics. There was no discernable evidence that the aliphatic organic content was affected by the stress environments. Our results indicate that plant stress during seed development can reduce both the physical and

Total phenolic content, antioxidant and antimicrobial activity of Equisetum arvense L.

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Kukrić Zoran

2013-01-01

Full Text Available The antioxidant and antimicrobial activity of Equisetum arvense L. harvested in a polluted urban area were investigated. The total phenolic content determined by a modified Folin-Ciocalteu method was 335.8 mg of GEA/g of the dried ethanol extract. Antioxidant activity determined by FRAP method was 28.7 mM Fe(II/g of extract, whereas antioxidant activity index for stable DPPH free radicals was 3.86. The results were compared with control antioxidants (gallic acid, vitamin C, BHA and BHT. Antimicrobial activity was tested by monitoring the impact of different extract concentrations through measuring the change in optical density of bacterial suspension over time and by determining MIC and MBC using macrodilution method. E. arvense extract has been effective on the tested microorganisms depending on the concentration and exposure time. The extract had the strongest antibacterial activity on Staphylococcus aureus, with MIC and MBC of 11.14 mg/mL and 22.28 mg/mL respectively, and the weakest effect on Bacillus cereus, with MIC of 89.10 mg/mL.

Treatment of wastewater containing phenol using a tubular ceramic membrane bioreactor.

Science.gov (United States)

Ersu, C B; Ong, S K

2008-02-01

The performance of a membrane bioreactor (MBR) with a tubular ceramic membrane for phenol removal was evaluated under varying hydraulic retention times (HRT) and a fixed sludge residence time (SRT) of 30 days. The tubular ceramic membrane was operated with a mode of 15 minutes of filtration followed by 15 seconds of permeate backwashing at a flux of 250 l m(-2)hr(-1) along with an extended backwashing of 30 seconds every 3 hours of operation, which maintained the transmembrane pressure (TMP) below 100 kPa. Using a simulated municipal wastewater with varying phenol concentrations, the chemical oxygen demand (COD) and phenol removals observed were greater than 88% with excellent suspended solids (SS) removal of 100% at low phenol concentrations (approx. 100 mg l(-1) of phenol). Step increases in phenol concentration showed that inhibition was observed between 600 to 800 mg l(-1) of phenol with decreased sludge production rate, mixed liquor suspended solids (MLSS) concentration, and removal performance. The sludge volume index (SVI) of the biomass increased to about 450 ml g(-1) for a phenol input concentration of 800 mg l(-1). When the phenol concentration was decreased to 100 mg l(-1), the ceramic tubular MBR was found to recover rapidly indicating that the MBR is a robust system retaining most of the biomass. Experimental runs using wastewater containing phenol indicated that the MBR can be operated safely without upsets for concentrations up to 600 mg l(-1) of phenol at 2-4 hours HRT and 30 days SRT.

Biosynthesis of caffeic acid in Escherichia coli using its endogenous hydroxylase complex

Directory of Open Access Journals (Sweden)

Lin Yuheng

2012-04-01

Full Text Available Abstract Background Caffeic acid (3,4-dihydroxycinnamic acid is a natural phenolic compound derived from the plant phenylpropanoid pathway. Caffeic acid and its phenethyl ester (CAPE have attracted increasing attention for their various pharmaceutical properties and health-promoting effects. Nowadays, large-scale production of drugs or drug precursors via microbial approaches provides a promising alternative to chemical synthesis and extraction from plant sources. Results We first identified that an Escherichia coli native hydroxylase complex previously characterized as the 4-hydroxyphenylacetate 3-hydroxylase (4HPA3H was able to convert p-coumaric acid to caffeic acid efficiently. This critical enzymatic step catalyzed in plants by a membrane-associated cytochrome P450 enzyme, p-coumarate 3-hydroxylase (C3H, is difficult to be functionally expressed in prokaryotic systems. Moreover, the performances of two tyrosine ammonia lyases (TALs from Rhodobacter species were compared after overexpression in E. coli. The results indicated that the TAL from R. capsulatus (Rc possesses higher activity towards both tyrosine and L-dopa. Based on these findings, we further designed a dual pathway leading from tyrosine to caffeic acid consisting of the enzymes 4HPA3H and RcTAL. This heterologous pathway extended E. coli native tyrosine biosynthesis machinery and was able to produce caffeic acid (12.1 mg/L in minimal salt medium. Further improvement in production was accomplished by boosting tyrosine biosynthesis in E. coli, which involved the alleviation of tyrosine-induced feedback inhibition and carbon flux redirection. Finally, the titer of caffeic acid reached 50.2 mg/L in shake flasks after 48-hour cultivation. Conclusion We have successfully established a novel pathway and constructed an E. coli strain for the production of caffeic acid. This work forms a basis for further improvement in production, as well as opens the possibility of microbial synthesis

Stress responses of duckweed (Lemna minor L.) and water velvet (Azolla filiculoides Lam.) to anionic surfactant sodium-dodecyl-sulphate (SDS).

Science.gov (United States)

Forni, C; Braglia, R; Harren, F J M; Cristescu, S M

2012-04-01

Surfactants are used for several purposes and recently they have attracted the attention for their ability to modify the behavior of other preexistent or co-disposed contaminants, although their use or discharge in wastewaters can represent a real or potential risk for the environment. Lemna minor L. and Azolla filiculoides Lam. are floating aquatic macrophytes, very effective in accumulating several pollutants including sodium dodecyl sulphate (SDS). In this work we evaluated the effects of SDS on these species by determining the stress ethylene production via laser-based trace gas detection, and the activities of enzymes involved in stress response, such as guaiacol peroxidase (G-POD), phenylalanine ammonia-lyase (PAL) and polyphenol-oxidase (PPO). Phenolics content was also determined. The macrophytes were treated with different concentrations of SDS for one week. SDS affected duckweed enzymatic activities and phenol content. While in the fern phenolics amount, PAL, G-POD and PPO activities were not affected by SDS except for 100 ppm SDS, the only concentration that was taken up and not completely degraded. Stress ethylene production was induced only in the fern treated with 50 and 100 ppm SDS. Copyright © 2011 Elsevier B.V. All rights reserved.

Purification and Characterization of Thermostable Cellulase from ...

African Journals Online (AJOL)

Available online at http://www.tjpr.org ... Methods: Molecular community structure of the newly selected thermophilic bacterial ... Keywords: Thermostable cellulase, Sugarcane bagasse, Purification, Characterization, Hot spring ... Currently, one.

Thermostability in rubredoxin and its relationship to mechanical rigidity

Science.gov (United States)

Rader, A. J.

2010-03-01

The source of increased stability in proteins from organisms that thrive in extreme thermal environments is not well understood. Previous experimental and theoretical studies have suggested many different features possibly responsible for such thermostability. Many of these thermostabilizing mechanisms can be accounted for in terms of structural rigidity. Thus a plausible hypothesis accounting for this remarkable stability in thermophilic enzymes states that these enzymes have enhanced conformational rigidity at temperatures below their native, functioning temperature. Experimental evidence exists to both support and contradict this supposition. We computationally investigate the relationship between thermostability and rigidity using rubredoxin as a case study. The mechanical rigidity is calculated using atomic models of homologous rubredoxin structures from the hyperthermophile Pyrococcus furiosus and mesophile Clostridium pasteurianum using the FIRST software. A global increase in structural rigidity (equivalently a decrease in flexibility) corresponds to an increase in thermostability. Locally, rigidity differences (between mesophilic and thermophilic structures) agree with differences in protection factors.

Thermostability in rubredoxin and its relationship to mechanical rigidity

International Nuclear Information System (INIS)

Rader, A J

2010-01-01

The source of increased stability in proteins from organisms that thrive in extreme thermal environments is not well understood. Previous experimental and theoretical studies have suggested many different features possibly responsible for such thermostability. Many of these thermostabilizing mechanisms can be accounted for in terms of structural rigidity. Thus a plausible hypothesis accounting for this remarkable stability in thermophilic enzymes states that these enzymes have enhanced conformational rigidity at temperatures below their native, functioning temperature. Experimental evidence exists to both support and contradict this supposition. We computationally investigate the relationship between thermostability and rigidity using rubredoxin as a case study. The mechanical rigidity is calculated using atomic models of homologous rubredoxin structures from the hyperthermophile Pyrococcus furiosus and mesophile Clostridium pasteurianum using the FIRST software. A global increase in structural rigidity (equivalently a decrease in flexibility) corresponds to an increase in thermostability. Locally, rigidity differences (between mesophilic and thermophilic structures) agree with differences in protection factors

Effects of Mutations and Ligands on the Thermostability of the l-Arginine/Agmatine Antiporter AdiC and Deduced Insights into Ligand-Binding of Human l-Type Amino Acid Transporters.

Science.gov (United States)

Ilgü, Hüseyin; Jeckelmann, Jean-Marc; Colas, Claire; Ucurum, Zöhre; Schlessinger, Avner; Fotiadis, Dimitrios

2018-03-20

The l-arginine/agmatine transporter AdiC is a prokaryotic member of the SLC7 family, which enables pathogenic enterobacteria to survive the extremely acidic gastric environment. Wild-type AdiC from Escherichia coli, as well as its previously reported point mutants N22A and S26A, were overexpressed homologously and purified to homogeneity. A size-exclusion chromatography-based thermostability assay was used to determine the melting temperatures ( T m s) of the purified AdiC variants in the absence and presence of the selected ligands l-arginine (Arg), agmatine, l-arginine methyl ester, and l-arginine amide. The resulting T m s indicated stabilization of AdiC variants upon ligand binding, in which T m s and ligand binding affinities correlated positively. Considering results from this and previous studies, we revisited the role of AdiC residue S26 in Arg binding and proposed interactions of the α-carboxylate group of Arg exclusively with amide groups of the AdiC backbone. In the context of substrate binding in the human SLC7 family member l-type amino acid transporter-1 (LAT1; SLC7A5), an analogous role of S66 in LAT1 to S26 in AdiC is discussed based on homology modeling and amino acid sequence analysis. Finally, we propose a binding mechanism for l-amino acid substrates to LATs from the SLC7 family.

Urinary excretion of deuterated metabolites in patients with tyrosinemia type I after oral loading with deuterated L-tyrosine

International Nuclear Information System (INIS)

Wadman, S.K.; Duran, M.; Ketting, D.; Bruinvis, L.; Sprang, F.J. van; Berger, R.; Smit, G.P.A.; Divry, P.; Farriaux, J.P.; Cartigny, B.

1983-01-01

The metabolic fate of orally given deuterated L-tyrosine, 50 mg/kg body weight, was investigated in seven patients with tyrosinemia type I in order to obtain evidence that the primary defect is at the level of fumarylacetoacetase. The absence of fumarylacetoacetase could be proved in liver biopsy specimens obtained from four patients. All patients excreted deuterated succinylacetoacetate and deuterated succinylacetone was detected in six out of seven. The total amount of these compounds was rather low; maximal 8.3% of the dose. The peak of the excretion occurred 3-6 h after loading, indicating an endogenous formation of the metabolites. All patients excreted deuterated 4-hydroxyphenyl acids, probably reflecting secondary 4-hydroxyphenylpyruvate dioxygenase deficiency connected with liver damage. 5. No evidence for other secondary routes of tyrosine metabolism was found. (Auth.)

O-(2-[{sup 18}F]Fluorethyl)-L-tyrosine in the diagnostics of brain tumors; O-(2-[{sup 18}F]Fluorethyl)-L-Tyrosin (FET) in der Diagnostik von Hirntumoren

Energy Technology Data Exchange (ETDEWEB)

Langen, K.J.; Stoffels, G. [Forschungszentrum Juelich (Germany). Inst. fuer Neurowissenschaften und Biophysik - Medizin

2009-06-15

Positron emission tomography (PET) using radiolabeled amino acids has shown great potential for a more accurate diagnosis of cerebral gliomas. Magnetic resonance imaging (MRI) is the investigation of choice for diagnosing cerebral glioma, but its capacity to differentiate tumor tissue from non-specific tissue changes is limited. ([{sup 18}F] Fluorethyl)-L-tyrosine (FET) is a new tracer for PET that can be produced with high efficiency and distributed on a wide clinical scale like [{sup 18}F]-Fluorodeoxyglucose (FDG). The use of FET PET allows better delineation of tumor margins and improves targeting of biopsy and radiotherapy, and planning surgery. In addition, amino acid imaging appears useful in distinguishing tumor recurrence from non-specific post-therapeutic scar tissue, predicting prognosis in low grade gliomas, and monitoring metabolic response during treatment. (orig.)

Low-temperature conditioning of "seed" cloves enhances the expression of phenolic metabolism related genes and anthocyanin content in 'Coreano' garlic (Allium sativum) during plant development.

Science.gov (United States)

Dufoo-Hurtado, Miguel D; Zavala-Gutiérrez, Karla G; Cao, Cong-Mei; Cisneros-Zevallos, Luis; Guevara-González, Ramón G; Torres-Pacheco, Irineo; Vázquez-Barrios, M Estela; Rivera-Pastrana, Dulce M; Mercado-Silva, Edmundo M

2013-11-06

Low-temperature conditioning of garlic "seed" cloves accelerated the development of the crop cycle, decreased plant growth, and increased the synthesis of phenolic compounds and anthocyanins in the outer scale leaves of the bulbs at harvest time, leading to 3-fold content increase compared with those conditioned at room temperature. Cold conditioning of "seed" cloves also altered the anthocyanin profile during bulb development and at harvest. Two new anthocyanins are reported for the first time in garlic. The high phenolics and anthocyanin contents in bulbs of plants generated from "seed" cloves conditioned at 5 °C for 5 weeks were preceded by overexpression of some putative genes of the phenolic metabolism [6-fold for phenylalanine ammonia lyase (PAL)] and anthocyanin synthesis [1-fold for UDP-sugar:flavonoid 3-O-glycosyltransferase (UFGT)] compared with those conditioned at room temperature.

Assessing wines based on total phenols, phenolic acids and ...

African Journals Online (AJOL)

The aim of this study was to investigate the phenolic profile of some red wines produced from native Turkish grape varieties (Vitis vinifera Öküzgözü, V. vinifera Boğazkere and V. vinifera Shiraz) and some red fruit wines produced from pomegranate (Punica granatum L.), myrtle (Myrtus communis L.) and black mulberry ...

Chondroitin Sulfate (CS) Lyases: Structure, Function and Application in Therapeutics.

Science.gov (United States)

Rani, Aruna; Patel, Seema; Goyal, Arun

2018-01-01

Glycosaminoglycans (GAGs) such as chondroitin sulfate (CS) are the chief natural polysaccharides which reside in biological tissues mainly in extracellular matrix. These CS along with adhesion molecules and growth factors are involved in central nervous system (CNS) development, cell progression and pathogenesis. The chondroitin lyases are the enzyme that degrade and alter the CS chains and hence modify various signalling pathways involving CS chains. These CS lyases are substrate specific, can precisely manipulate the CS polysaccharides and have various biotechnological, medical and therapeutic applications. These enzymes can be used to produce the unsaturated oligosaccharides, which have immune-modulatory, anti-inflammatory and neuroprotective properties. This review focuses on the major breakthrough of the chondroitin sulfate degrading enzymes, their structures and functioning mechanism. This also provides comprehensive information regarding production, purification, characterization of CS lyases and their major applications, both established as well as emerging ones such as neural development. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Structural Snapshots of an Engineered Cystathionine-γ-lyase Reveal the Critical Role of Electrostatic Interactions in the Active Site

Energy Technology Data Exchange (ETDEWEB)

Yan, Wupeng; Stone, Everett; Zhang, Yan Jessie

2017-02-01

Enzyme therapeutics that can degrade l-methionine (l-Met) are of great interest as numerous malignancies are exquisitely sensitive to l-Met depletion. To exhaust the pool of methionine in human serum, we previously engineered an l-Met-degrading enzyme based on the human cystathionine-γ-lyase scaffold (hCGL-NLV) to circumvent immunogenicity and stability issues observed in the preclinical application of bacterially derived methionine-γ-lyases. To gain further insights into the structure–activity relationships governing the chemistry of the hCGL-NLV lead molecule, we undertook a biophysical characterization campaign that captured crystal structures (2.2 Å) of hCGL-NLV with distinct reaction intermediates, including internal aldimine, substrate-bound, gem-diamine, and external aldimine forms. Curiously, an alternate form of hCGL-NLV that crystallized under higher-salt conditions revealed a locally unfolded active site, correlating with inhibition of activity as a function of ionic strength. Subsequent mutational and kinetic experiments pinpointed that a salt bridge between the phosphate of the essential cofactor pyridoxal 5'-phosphate (PLP) and residue R62 plays an important role in catalyzing β- and γ-eliminations. Our study suggests that solvent ions such as NaCl disrupt electrostatic interactions between R62 and PLP, decreasing catalytic efficiency.

Rapid phenolic O-glycosylation of small molecules and complex unprotected peptides in aqueous solvent

Science.gov (United States)

Wadzinski, Tyler J.; Steinauer, Angela; Hie, Liana; Pelletier, Guillaume; Schepartz, Alanna; Miller, Scott J.

2018-06-01

Glycosylated natural products and synthetic glycopeptides represent a significant and growing source of biochemical probes and therapeutic agents. However, methods that enable the aqueous glycosylation of endogenous amino acid functionality in peptides without the use of protecting groups are scarce. Here, we report a transformation that facilitates the efficient aqueous O-glycosylation of phenolic functionality in a wide range of small molecules, unprotected tyrosine, and tyrosine residues embedded within a range of complex, fully unprotected peptides. The transformation, which uses glycosyl fluoride donors and is promoted by Ca(OH)2, proceeds rapidly at room temperature in water, with good yields and selective formation of unique anomeric products depending on the stereochemistry of the glycosyl donor. High functional group tolerance is observed, and the phenol glycosylation occurs selectively in the presence of virtually all side chains of the proteinogenic amino acids with the singular exception of Cys. This method offers a highly selective, efficient, and operationally simple approach for the protecting-group-free synthesis of O-aryl glycosides and Tyr-O-glycosylated peptides in water.

Thermostable endoglucanases in the liquefaction of hydrothermally pretreated wheat straw

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Siika-aho Matti

2011-01-01

Full Text Available Abstract Background Thermostable enzymes have several benefits in lignocellulose processing. In particular, they potentially allow the use of increased substrate concentrations (because the substrate viscosity decreases as the temperature increases, resulting in improved product yields and reduced capital and processing costs. A short pre-hydrolysis step at an elevated temperature using thermostable enzymes aimed at rapid liquefaction of the feedstock is seen as an attractive way to overcome the technical problems (such as poor mixing and mass transfer properties connected with high initial solid loadings in the lignocellulose to ethanol process. Results The capability of novel thermostable enzymes to reduce the viscosity of high-solid biomass suspensions using a real-time viscometric measurement method was investigated. Heterologously expressed enzymes from various thermophilic organisms were compared for their ability to liquefy the lignocellulosic substrate, hydrothermally pretreated wheat straw. Once the best enzymes were identified, the optimal temperatures for these enzymes to decrease substrate viscosity were compared. The combined hydrolytic properties of the thermostable preparations were tested in hydrolysis experiments. The studied mixtures were primarily designed to have good liquefaction potential, and therefore contained an enhanced proportion of the key liquefying enzyme, EGII/Cel5A. Conclusions Endoglucanases were shown to have a superior ability to rapidly reduce the viscosity of the 15% (w/w; dry matter hydrothermally pretreated wheat straw. Based on temperature profiling studies, Thermoascus aurantiacus EGII/Cel5A was the most promising enzyme for biomass liquefaction. Even though they were not optimized for saccharification, many of the thermostable enzyme mixtures had superior hydrolytic properties compared with the commercial reference enzymes at 55°C.

Thermophilic growth and enzymatic thermostability are polyphyletic traits within Chaetomiaceae.

Science.gov (United States)

van den Brink, Joost; Facun, Kryss; de Vries, Michel; Stielow, J Benjamin

2015-12-01

Thermophilic fungi have the potential to produce industrial-relevant thermostable enzymes, in particular for the degradation of plant biomass. Sordariales is one of the few fungal orders containing several thermophilic taxa, of which many have been associated with the production of thermostable enzymes. The evolutionary affiliation of Sordariales fungi, especially between thermophiles and non-thermophilic relatives, is however poorly understood. Phylogenetic analysis within the current study was based on sequence data, derived from a traditional Sanger and highly multiplexed targeted next generation sequencing approach of 45 isolates. The inferred phylogeny and detailed growth analysis rendered the trait 'thermophily' as polyphyletic within Chaetomiaceae (Sordariales, Sordariomycetes), and characteristic to: Myceliophthora spp., Thielavia terrestris, Chaetomium thermophilum, and Mycothermus thermophilus. Compared to mesophiles, the isolates within thermophilic taxa produced enzyme mixtures with the highest thermostability of known cellulase activities. Temperature profiles of the enzyme activities correlated strongly with the optimal growth temperatures of the isolates but not with their phylogenetic relationships. This strong correlation between growth and enzyme characteristics indicated that detailed analysis of growth does give predictive information on enzyme physiology. The variation in growth and enzyme characteristics reveals these fungi as an excellent platform to better understand fungal thermophily and enzyme thermostability. Copyright © 2015 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

Anaerobic biogranulation in a hybrid reactor treating phenolic waste

International Nuclear Information System (INIS)

Ramakrishnan, Anushyaa; Gupta, S.K.

2006-01-01

Granulation was examined in four similar anaerobic hybrid reactors 15.5 L volume (with an effective volume of 13.5 L) during the treatment of synthetic coal wastewater at the mesophilic temperature of 27 ± 5 deg. C. The hybrid reactors are a combination of UASB unit at the lower part and an anaerobic filter at the upper end. Synthetic wastewater with an average chemical oxygen demand (COD) of 2240 mg/L, phenolics concentration of 752 mg/L and a mixture of volatile fatty acids was fed to three hybrid reactors. The fourth reactor, control system, was fed with a wastewater containing sodium acetate and mineral nutrients. Coal waste water contained phenol (490 mg/L); m-, o-, p-cresols (123.0, 58.6, 42 mg/L); 2,4-, 2,5-, 3,4- and 3,5-dimethyl phenols (6.3, 6.3, 4.4 and 21.3 mg/L) as major phenolic compounds. A mixture of anaerobic digester sludge and partially granulated sludge (3:1) were used as seed materials for the start up of the reactors. Granules were observed after 45 days of operation of the systems. The granules ranged from 0.4 to 1.2 mm in diameter with good settling characteristics with an SVI of 12 mL/g SS. After granulation, the hybrid reactor performed steadily with phenolics and COD removal efficiencies of 93% and 88%, respectively at volumetric loading rate of 2.24 g COD/L d and hydraulic retention time of 24 h. The removal efficiencies for phenol and m/p-cresols reached 92% and 93% (corresponding to 450.8 and 153 mg/L), while o-cresol was degraded to 88% (corresponding to 51.04 mg/L). Dimethyl phenols could be removed completely at all the organic loadings and did not contribute much to the residual organics. Biodegradation of o-cresol was obtained in the hybrid-UASB reactors

Influence of high temperature and ethanol on thermostable lignocellulolytic enzymes

DEFF Research Database (Denmark)

Skovgaard, Pernille Anastasia; Jørgensen, Henning

2013-01-01

the influence of temperature and ethanol on enzyme activity and stability in the distillation step, where most enzymes are inactivated due to high temperatures. Two enzyme mixtures, a mesophilic and a thermostable mixture, were exposed to typical process conditions [temperatures from 55 to 65 °C and up to 5...... % ethanol (w/v)] followed by specific enzyme activity analyses and SDS-PAGE. The thermostable and mesophilic mixture remained active at up to 65 and 55 °C, respectively. When the enzyme mixtures reached their maximum temperature limit, ethanol had a remarkable influence on enzyme activity, e.g., the more...... ethanol, the faster the inactivation. The reason could be the hydrophobic interaction of ethanol on the tertiary structure of the enzyme protein. The thermostable mixture was more tolerant to temperature and ethanol and could therefore be a potential candidate for recycling after distillation....

Rapid enzymatic analysis of plasma for tyrosine.

Science.gov (United States)

Shimizu, H; Taniguchi, K; Sugiyama, M; Kanno, T

1990-01-01

In this rapid, simple, and convenient enzymatic method for measurement of tyrosine in plasma, tyrosine is converted to tyramine by action of tyrosine decarboxylase (EC 4.1.1.25) and the tyramine produced is oxidized to p-hydroxybenzyl aldehyde and hydrogen peroxide by action of tyramine oxidase (EC 1.4.3.9). The hydrogen peroxide is reacted with 4-aminoantipyrine and N-ethyl-N-(2-hydroxy-3-sulfopropyl)-m-toluidine in the presence of peroxidase (EC 1.11.1.7) to obtain quinoneimine dye, the absorbance of which is measured at 570 nm. Thus tyrosine is measured in the visible range. The CV was 4.6% or less, and the measurement was unaffected by other amino acids, except for phenylalanine. The values obtained (y) correlated well with those obtained with an amino acid analyzer (x): y = 0.902x + 3.92 mumol/L (Syx = 12.3; r = 0.985; n = 54).

An automated synthesis module for preparation of L-3-[123I]iodo-alpha-methyl tyrosine

International Nuclear Information System (INIS)

Luurtsema, Gert; Jager, Pieter L.; Piers, Albertus; Hooge, Marjolijn N. de

2001-01-01

L-3-[ 123 I]iodo-alpha-methyl tyrosine (IMT) is an artificial amino acid suitable for SPECT imaging of various tumours. Manual synthesis of this radiopharmaceutical is reliable, but time-consuming and may require handling of large quantities of radioactivity. We developed an automated IMT synthesis module, which prepares a ready-to-inject product that meets radiopharmaceutical requirements and is identical to the manually synthesised equivalent. Current advantages include decreased operator assistance time and reduced radiation exposure. Application may be extended to other radiopharmaceuticals, including high-dose preparations for therapeutic use

Effect of 60Co gamma radiation on the levels of phenolic compounds from crude extracts of bark of Spondias luta L

International Nuclear Information System (INIS)

Santos, Gustavo H.F.; Silva, Hianna A.M.F.; Melo, Mychely S.; Silva, Edvane B.

2013-01-01

Spondias luta L. (Anacardiaceae), popularly known as cajazeira, is a plant widespread in several regions of Brazil, famous for containing phenolic compounds, which are responsible for your characteristic astringent. Ionizing radiations have the ability to cross the material, ionizing atoms and molecules, causing changes in atoms and molecules important. It is known ionizing radiation promotes quantitative and qualitative changes in plant materials, increasing, decreasing or inactivating secondary substances. The objective of this work was to evaluate the effect of gamma radiation as a modifier of the activity of the phenolic compounds of the bark extract of S. luta L. Methods: For the dosage of phenol extracts (control, irradiated with 5 kGy, 10 kGy, 15 kGy and 20 kGy) were diluted in methanol to a final concentration of 200 mg / L. In test tubes were added 50 μL of extract plus 1 ml of distilled water and 500 μl of Folin (diluted 1:10). After 10 minutes in a dark chamber was added 2.5 ml of calcium carbonate to 20% and the content of the tube was homogenized. After 20 minutes was performed with a spectrophotometer at 735 nm. The assay was performed in triplicate and calculated from a standard curve solution of gallic acid and expressed in μEAG (GAE/mg extract). Results: The control extracts, irradiated to 5 kGy, 10 kGy, 15 kGy and 20 kGy, had, respectively, 6.25, 6.70, 6.25, 6.85, 6.45 μEAG/mg of extract. Conclusion: The results showed no significant change in the amount of phenolic compounds, showing that these compounds are radioresistant extract these doses. (author)

New tyrosinase inhibitory decapeptide: Molecular insights into the role of tyrosine residues.

Science.gov (United States)

Ochiai, Akihito; Tanaka, Seiya; Imai, Yuta; Yoshida, Hisashi; Kanaoka, Takumi; Tanaka, Takaaki; Taniguchi, Masayuki

2016-06-01

Tyrosinase, a rate-limiting enzyme in melanin biosynthesis, catalyzes the hydroxylation of l-tyrosine to 3,4-dihydroxy-l-phenylalanine (l-dopa) (monophenolase reaction) and the subsequent oxidation of l-dopa to l-dopaquinone (diphenolase reaction). Thus, tyrosinase inhibitors have been proposed as skin-lightening agents; however, many of the existing inhibitors cannot be widely used in the cosmetic industry due to their high cytotoxicity and instability. On the other hand, some tyrosinase inhibitory peptides have been reported as safe. In this study, we found that the peptide TH10, which has a similar sequence to the characterized inhibitory peptide P4, strongly inhibits the monophenolase reaction with a half-maximal inhibitory concentration of 102 μM. Seven of the ten amino acid residues in TH10 were identical to P4; however, TH10 possesses one N-terminal tyrosine, whereas P4 contains three tyrosine residues located at its N-terminus, center, and C-terminus. Subsequent analysis using sequence-shuffled variants indicated that the tyrosine residues located at the N-terminus and center of P4 have little to no contribution to its inhibitory activity. Furthermore, docking simulation analysis of these peptides with mushroom tyrosinase demonstrated that the active tyrosine residue was positioned close to copper ions, suggesting that TH10 and P4 bind to tyrosinase as a substrate analogue. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Expression and properties of the highly alkalophilic phenylalanine ammonia-lyase of thermophilic Rubrobacter xylanophilus.

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Klaudia Kovács

Full Text Available The sequence of a phenylalanine ammonia-lyase (PAL; EC: 4.3.1.24 of the thermophilic and radiotolerant bacterium Rubrobacter xylanophilus (RxPAL was identified by screening the genomes of bacteria for members of the phenylalanine ammonia-lyase family. A synthetic gene encoding the RxPAL protein was cloned and overexpressed in Escherichia coli TOP 10 in a soluble form with an N-terminal His6-tag and the recombinant RxPAL protein was purified by Ni-NTA affinity chromatography. The activity assay of RxPAL with l-phenylalanine at various pH values exhibited a local maximum at pH 8.5 and a global maximum at pH 11.5. Circular dichroism (CD studies showed that RxPAL is associated with an extensive α-helical character (far UV CD and two distinctive near-UV CD peaks. These structural characteristics were well preserved up to pH 11.0. The extremely high pH optimum of RxPAL can be rationalized by a three-dimensional homology model indicating possible disulfide bridges, extensive salt-bridge formation and an excess of negative electrostatic potential on the surface. Due to these properties, RxPAL may be a candidate as biocatalyst in synthetic biotransformations leading to unnatural l- or d-amino acids or as therapeutic enzyme in treatment of phenylketonuria or leukemia.

Dosimetric estimation of O-(3-18F-fluoropropyl)-L-tyrosine in human based on mice biodistribution data

International Nuclear Information System (INIS)

Tang Ganghua; Wang Mingfang; Luo Lei; Gan Manquan; Tang Xiaolan

2002-01-01

Objective: To estimate the radiation absorbed doses in humans due to intravenous administration of O-(3- 18 F-fluoropropyl)-L-tyrosine (FPT) based on mice biodistribution data and appraise the security of FPT in humans. Methods: FPT was injected into mice through a tail vein. At 10, 30, 60, 120 and 180 min after injection, the mice were killed by cervical fracture and biodistribution in mice were determined. Human dosimetric estimation was performed from the biodistribution of FPT in mice and the standard MIRD method using fractional radioactivity-time curves for humans. Results: The bone in human was the organ receiving highest dose of 4.29 x 10 -3 mGy/MBq, the brain received lowest dose of 1.57 x 10 -3 mGy/MBq, and other organs received doses between 1.8 x 10 -3 and 2.4 x 10 -3 mGy/MBq. The effective dose was estimated to be 9.15 x 10 -3 mSv/MBq. These results were comparable to values reported by foreign authors on the radiation dosimetry of O-(2- 18 F-fluoroethyl)-L-tyrosine. Conclusion: Human dosimetric estimation can be performed based on mice biodistribution data. The study provides an important data for clinical safety of FPT

Comparative study between phenol and imidazole derivatives in radiolabeling of some steroid hormones

International Nuclear Information System (INIS)

Sallam, Kh.M.

2010-01-01

A phenol or imidazole ring is rarely present in steroid hormones, So, the molecule of steroid hormone requires chemical modification by addition of an iodinable residue like phenol or imedazole. So that the comparative study between phenol derivatives, include tyrosine methyl ester (TME) and tyramine, and imidazole derivatives, like histamine and histedine methyl ester (HME), for radiolabeling of some steroid hormones include estradiol and testosterone is the aim of the present study. The conjugation step was carried using mixed anhydride method and followed by radioiodination using iodogen as an oxidizing agent. Purification step was carried out using high performance liquid chromatography (HPLC). Optimization and validation of the tracer were carried out. Immunoreactivity of the all obtained tracers was check by using specific polyclonal antibodies. The results indicated that imidazols derivatives are more suitable from immunoreactivity view and storage period.

Radical Scavenging Capacity of Methanolic Phillyrea latifolia L. Extract: Anthocyanin and Phenolic Acids Composition of Fruits

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Naciye Erkan

2013-01-01

Full Text Available Radical scavenging capacity of a crude methanolic extract from the fruits of Phillyrea latifolia L., commonly known as green olive tree or mock privet, was investigated with reference to anthocyanin standards, as flavonoids, and phenolic acid standards, as phenylpropanoids. Characterization with high performance liquid chromatography-diode array detection (HPLC-DAD indicated the presence of keracyanin, kuromanin, cyanidin, ferulic acid, caffeic acid and rosmarinic acid at amounts of 289.1, 90.4, 191.4, 225.2, 221.2 and 190.1 mg/100 g fresh weight (FW of fruits, respectively. Chlorogenic and p-coumaric acids were found to exist in lower amounts. Trolox equivalent antioxidant capacity (TEAC and IC50 values of the plant extract were found to be 1.8 mM Trolox equivalents (TE/g FW of fruits and 69.4 µg/mL, respectively, indicating the close radical scavenging activity of the extract to those of keracyanin and p-coumaric acid. The crude methanolic P. latifolia L. fruit extract was seen to be fairly potent in radical scavenging. Total phenolic content (TPC of the plant extract was found to be 1652.9 mg gallic acid equivalent (GAE/100 g FW of fruits.

Feeding-induced phenol production in Capsicum annuum L. influences Spodoptera litura F. larval growth and physiology.

Science.gov (United States)

Movva, Vijaya; Pathipati, Usha Rani

2017-05-01

We studied the role of induced plant phenols as a defense response to insect herbivory. Phenolic compounds were induced in Capsicum annuum L., the source of many culinary peppers, after feeding by different stages of the insect pest, Spodoptera litura F. The phenols were identified and quantified using high performance liquid chromatography (HPLC) and effects produced by these phenols on larval development were studied. Vanillic acid was identified in plants challenged by second, fourth, and fifth instar larvae, but not in plants challenged by third instar nor unchallenged plants. Syringic acid production was induced in chili plants infested with second (0.429 ± 0.003 μg/g fresh weight, fourth (0.396 ± 0.01 μg/g fresh weight), and fifth instar (5.5 ± 0.06 μg/g fresh weight) larvae, compared to untreated plants (0.303 ± 0.01 μg/g fresh weight) plants. Leaves surface treated with the rutin deterred oviposition. Dietary exposure to chlorogenic acid, vanillic acid, syringic acid, sinapic acid, and rutin led to enhanced activities of detoxifying enzymes, β-glucosidase, carboxyl esterase, glutathione S-transferase, and glutathione reductase in the midgut tissues of all the larval instars, indicating the toxic nature of these compounds. Protein carbonyl content and acetylcholinesterase activity was analyzed to appreciate the role of induced plant phenols in insect protein oxidation and terminating nerve impulses. © 2017 Wiley Periodicals, Inc.

Autophosphorylation of JAK2 on tyrosines 221 and 570 regulates its activity

DEFF Research Database (Denmark)

Argetsinger, Lawrence S; Kouadio, Jean-Louis K; Steen, Hanno

2004-01-01

or which of the 49 tyrosines in JAK2 are autophosphorylated. In this study, mass spectrometry and two-dimensional peptide mapping were used to determine that tyrosines 221, 570, and 1007 in JAK2 are autophosphorylated. Phosphorylation of tyrosine 570 is particularly robust. In response to growth hormone......, JAK2 was rapidly and transiently phosphorylated at tyrosines 221 and 570, returning to basal levels by 60 min. Analysis of the sequences surrounding tyrosines 221 and 570 in JAK2 and tyrosines in other proteins that are phosphorylated in response to ligands that activate JAK2 suggests that the YXX......[L/I/V] motif is one of the motifs recognized by JAK2. Experiments using JAK2 with tyrosines 221 and 570 mutated to phenylalanine suggest that tyrosines 221 and 570 in JAK2 may serve as regulatory sites in JAK2, with phosphorylation of tyrosine 221 increasing kinase activity and phosphorylation of tyrosine 570...

The diagnostic accuracy of detecting malignant transformation of low-grade glioma using O-(2-[F]fluoroethyl)-l-tyrosine positron emission tomography

DEFF Research Database (Denmark)

Bashir, Asma; Brennum, Jannick; Broholm, Helle

2018-01-01

OBJECTIVE The diagnostic accuracy of O-(2-[18F]fluoroethyl)-l-tyrosine (FET) PET scanning in detecting the malignant transformation of low-grade gliomas (LGGs) is controversial. In this study, the authors retrospectively assessed the diagnostic potential of FET PET in patients with MRI-suspected ...

Study on the presence and influence of phenolic compounds in callogenesis and somatic embryo development of cocoa (Theobroma cacao L..

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Sulistyani Pancaningtyas

2015-04-01

Full Text Available Cocoa (Theobroma cacao L. like most tropical trees is recalcitrant in tissue culture. Somatic embryogenesis is generally efficient micropropagation technique to multiply elite material. However, Somatic embryogenesis in cocoa is difficult and this species is considered as recalcitrant. One of the factors often considered as a component of in vitro recalsitrance is a high phenolic content and oxidation of these compounds. In cocoa tissue culture accumulate large amounts of poliphenolics compounds which probably impair further development. This study was conducted to investigate the composition of phenolic compounds in cocoa flower and leaves, and their changes troughout the somatic embryogenesis process. Calli were induced in cacao floral and leaves explants on a half-strenght Murashige and Skoog medium containing 30 g/L Glucose and combination of 2,4 dichlorophenoxyacetic acid (2,4 D with kinetin (kin. Total polyphenol content was observed on Sulawesi 1 cocoa clone. Embryogenic and non-embryogenic callus were also compared. The percentage of callus production from flower tissue is 85%, percentage of embryogenic callus 40 %, although the percentage of somatic embryo production from embryogenic callus callus is 70%. The conservation of callus into somatic embryos followed by decline in phenol content and an increase in peroxidase. The synthesis kinetics for these compounds in calli, under different somatic embryogenesis conditions, revealed a higher concentration under non-embryogenic conditions. So that, phenolic compound can influence the production of calli and an absence the phenolic compound can enhance production of somatic embryo.

Optimization of medium composition for thermostable protease ...

African Journals Online (AJOL)

SERVER

2008-04-17

Apr 17, 2008 ... Optimization of the fermentation medium for maximization of thermostable neutral protease production by Bacillus sp. ..... Each contour curve represented an infinite number of combinations of two ..... Production in sea-water of.

Exogenous cellulases of thermophilic micromycetes. Pt. 2. Thermostability of enzyme preparations

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Kvesitadze, G; Gogilashvili, L; Svanidze, R; Buachidze, T; Chirgadze, L; Nizharadze, D

1986-01-01

The ability of a large number of higher fungi to form extracellular cellulases is investigated. Some representatives of these fungi grow at 40-50/sup 0/C, and form extracellular cellulases exceeding cellulases of mesophilic fungi in thermostability. It is shown that cellulases of higher thermophilic fungi differ by their thermostability. The temperature optimum of cellulase action of higher fungi occurs within 60-62/sup 0/C.

Improved thermostability and enzyme activity of a recombinant phyA mutant phytase from Aspergillus niger N25 by directed evolution and site-directed mutagenesis.

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Tang, Zizhong; Jin, Weiqiong; Sun, Rong; Liao, Yan; Zhen, Tianrun; Chen, Hui; Wu, Qi; Gou, Lin; Li, Chenlei

2018-01-01

We previously constructed three recombinant phyA mutant strains (PP-NP m -8, PP-NP ep -6A and I44E/T252R-PhyA), showing improved catalytic efficiency or thermostability of Aspergillus niger N25 phytase, by error-prone PCR or site-directed mutagenesis. In this study, directed evolution and site-directed mutagenesis were further applied to improve the modified phytase properties. After one-round error-prone PCR for phytase gene of PP-NP ep -6A, a single transformant, T195L/Q368E/F376Y, was obtained with the significant improvements in catalytic efficiency and thermostability. The phytase gene of T195L/Q368E/F376Y, combined with the previous mutant phytase genes of PP-NP ep -6A, PP-NP m -8 and I44E/T252R-PhyA, was then sequentially modified by DNA shuffling. Three genetically engineered strains with desirable properties were then obtained, namedQ172R, Q172R/K432R andQ368E/K432R. Among them, Q172R/K432R showed the highest thermostability with the longest half-life and the greatest remaining phytase activity after heat treatment, while Q368E/K432R showed the highest catalytic activity. Five substitutions (Q172R, T195L, Q368E, F376Y, K432R) identified from random mutagenesis were added sequentially to the phytase gene of PP-NP ep -6A to investigate how the mutant sites influence the properties of phytase. Characterization and structural analysis demonstrated that these mutations could produce cumulative or synergistic improvements in thermostability or catalytic efficiency of phytase. Copyright © 2017 Elsevier Inc. All rights reserved.

Development of novel techniques to extract phenolic compounds from Romanian cultivars of Prunus domestica L. and their biological properties.

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Mocan, Andrei; Diuzheva, Alina; Carradori, Simone; Andruch, Vasil; Massafra, Chiara; Moldovan, Cadmiel; Sisea, Cristian; Petzer, Jacobus P; Petzer, Anél; Zara, Susi; Marconi, Guya Diletta; Zengin, Gokhan; Crișan, Gianina; Locatelli, Marcello

2018-04-21

In the present work, fourteen cultivars of Prunus domestica were analysed to investigate their phenolic pattern with the purpose of using the leaves as potential resources of bioactive compounds in the pharmaceutical and food industry. Microwave-assisted extraction (MAE), dispersive liquid-liquid microextraction and sugaring-out liquid-liquid extraction techniques were optimized in order to obtain an exhaustive multi-component panel of phenolic compounds. The best phenolic-enriched recovery was achieved using MAE in water:methanol (30:70), and this procedure was further applied for quantitative analysis of phenolic compounds in real samples. In order to prove the safeness of these extracts, the biological potential of the Prunus cultivars was tested by several in vitro antioxidant and enzyme inhibitory assays. Moreover, their cytotoxicity was evaluated on human gingival fibroblasts (HGFs), and in most of the cases the treatment with different concentrations of extracts didn't show cytotoxicity up to 500 μg/mL. Only 'Carpatin' and 'Minerva' cultivars, at 250 and 500 μg/mL, reduced partially cell viability of HGFs population. Noteworthy, Centenar cultivar was the most active for the α-glucosidase inhibition (6.77 mmolACAE/g extract), whereas Ialomița cultivar showed the best antityrosinase activity (23.07 mgKAE/g extract). Overall, leaves of P. domestica represent a rich alternative source of bioactive compounds. Copyright © 2018. Published by Elsevier Ltd.

Evaluation of thermostable enzymes for bioethanol processing

DEFF Research Database (Denmark)

Skovgaard, Pernille Anastasia

of fermentable sugars (glucose) as cellulose is tightly linked to hemicellulose and lignin. Lignocellulose is disrupted during pretreatment, but to degrade cellulose to single sugars, lignocellulolytic enzymes such as cellulases and hemicellulases are needed. Lignocellulolytic enzymes are costly...... for the ioethanol production, but the expenses can be reduced by using thermostable enzymes, which are known for their increased stability and inhibitor olerance. However, the advantage of using thermostable enzymes has not been studied thoroughly and more knowledge is needed for development of bioethanol processes....... Enzymes are added to the bioethanol process after pretreatment. For an efficient sugar and ethanol yield, the solids content of biomass is normally increased, which results in highly viscous slurries that are difficult to mix. Therefore, the first enzymatic challenge is to ensure rapid reduction...

Phenol oxidation with hydrogen peroxide

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Ramiez Cortina, R.C.; Hernadez Perez, I. [Univ. Autonoma Metropolitana - Azcapotzalco, Div. de CBI, Dept. de Energia, Azcapotzalco (Mexico); Ortiz Lozoya, C.E. [Univ. Autonoma Metropolitana - Azcapotzalco, Div. de CBI, Dept. de Energia, Azcapotzalco (Mexico)]|[Inst. Mexicano del Petroleo (Mexico); Alonso Gutierrez, M.S. [Inst. National Polytechnique, ENSCT, Lab. of Chimie Agro-Industrielle, Toulouse (France)

2003-07-01

In this work the process application of advanced oxidation is investigated with hydrogen peroxide, for the phenol destruction. The experiments were carried out in a glass reactor of 750 mL. Three phenol concentrations were studied (2000, 1000 and 500 ppm) being oxidized with H{sub 2}O{sub 2} (1, 2 and 3 M). The tests of oxidation had a reaction time of 48 h at ambient temperature and pressure. The phenol degradation was determined as COD at different reaction times and intermediate oxidation products were analyzed by chromatography. The results of this study show that it is possible to degrade phenol (1000 ppm) until 90% with H{sub 2}O{sub 2} 2M. Being achieved the best efficiency with a good molar relationship of H{sub 2}O{sub 2}/phenol. Intends a reaction outline in the degradation of the phenol. (orig.)

DPPH RADICAL SCAVENGING ACTIVITY, TOTAL PHENOLICS AND FLAVONOIDS OF WATER SOLUBLE EXTRACTS DERIVED FROM LEAVES AND FRUIT OF Ficus carica L. AND Ficus parietalis Bl.

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Oktavia Tri Wahyuni

2016-08-01

Full Text Available Ficus carica L and Ficus parietalis Bl. (Moraceae are closely related plants which also known in Indonesia as Figs L. Considering the wide therapeutic value of Figs, this research was aimed to evaluate the DPPH-radical scavenging activity of both plants as well as their total phenolic and flavonoids. Extracts were produced by using boiled water and diluted to gain the desired concentration. Analyses were performed by using UV-vis spectrophotometer. Radical scavenging activity testing was done by using radical of DPPH (2,2-diphenyl-1-pycrylhydrazyl to determine the IC50s. The determination of total phenolic was conducted by using Folin-Ciocalteau method and calculated as Gallic Acid Equivalence (GAE. The total flavonoid was measured by using AlCl3-reagents, and calculated as Rutin Equivalence (RE. Afterwards, the radical scavenging activity was correlated to the total phenolic and flavonoids contents. The results showed that the water soluble extract of F. carica fruit had the best IC50 value of 33.38 mg/mL, followed successively by the F. parietalis fruit (35.69 mg/mL, F. parietalis leaves (44.01 mg/mL and the F. carica leaves (76.38 mg/mL. The highest content of total phenolic was shown by the leaves of F. parietalis (1.46% w/w GAE and the lowest was in the fruit or F. carica (0.36% w/w GAE. The highest flavonoid content was detected in the leaves of F. carica (1.42% w/w RE and the lowest was in the F. parietalis fruit (0.20% w/w RE. Correlation analyses of the IC50 values vs. the total phenolic and the flavonoids contents resulted in a positive slope having R2 values as 0.5362 and 0.9895, respectively. As a conclusion, the total flavonoid content influenced the DPPH radical scavenging activity by 98.95%, while the total phenolic content influence was only 53.62%.

Peroxidase, phenolics, and antioxidative capacity of common mullein (Verbascum thapsus L. grown in a zinc excess

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Morina Filis

2008-01-01

Full Text Available Common mullein (Verbascum thapsus L. is the dominant plant species at a disposal site polluted with metal from the hydrometallurgical jarosite zinc production process. Seeds collected at the site were germinated and plants were grown hydroponically under controlled conditions in a excess of Zn. Induction of total soluble POD activity in the root occurred at 1, 5, and 10 mM Zn, indicating Zn accumulation within the root. Accumulation of Zn in leaves was not accompanied by changes in POD activity, but resulted in gradual increase of total antioxidative capacity, which could be partly attributed to accumulation of soluble phenolics. The role of the phenolics/POD system in defense of V. thapsus against zinc is discussed.

Phenolic profiles in leaves of chicory cultivars (Cichorium intybus L.) as influenced by organic and mineral fertilizers.

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Sinkovič, Lovro; Demšar, Lea; Žnidarčič, Dragan; Vidrih, Rajko; Hribar, Janez; Treutter, Dieter

2015-01-01

Chicory (Cichorium intybus L.) is a typical Mediterranean vegetable, and it shows great morphological diversity, including different leaf colours. Five cultivars commonly produced in Slovenia ('Treviso', 'Verona', 'Anivip', 'Castelfranco', 'Monivip') were grown in pots under controlled conditions in a glasshouse, with organic and/or mineral fertilizers administered to meet nitrogen requirements. HPLC analysis was carried out to study the phenolic compositions of the leaves. A total of 33 phenolic compounds were extracted from these chicory leaves and were quantitatively evaluated in an HPLC-DAD-based metabolomics study. Among the cultivars, the highest TPC was seen for 'Treviso' (300.1 mg/100 g FW), and the lowest, for 'Castelfranco' (124.9 mg/100g FW). Across the different treatments, the highest TPC was in the control samples (254.3 mg/100 g FW), and the lowest for the organic (128.6 mg/100 g FW) and mineral fertilizer (125.5 mg/100 g FW) treatments. The predominant phenolic compounds in all of the samples were hydroxycinnamic acids, including chlorogenic and cichoric acid. Fertilizer administration provides a discriminant classification of the chicory cultivars according to their phenolic compounds. Copyright © 2014 Elsevier Ltd. All rights reserved.

Identification and Quantification of Avenanthramides and Free and Bound Phenolic Acids in Eight Cultivars of Husked Oat ( Avena sativa L) from Finland.

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Multari, Salvatore; Pihlava, Juha-Matti; Ollennu-Chuasam, Priscilla; Hietaniemi, Veli; Yang, Baoru; Suomela, Jukka-Pekka

2018-03-21

Finland is the second largest oat producer in Europe. Despite the existing knowledge of phenolics in oat, there is little information on the phenolic composition of oats from Finland. The aim of the study was to investigate the concentrations of free and bound phenolic acids, as well as avenanthramides in eight Finnish cultivars of husked oat ( Avena sativa L.). Seven phenolic acids and one phenolic aldehyde were identified, including, in decreasing order of abundance: p-coumaric, ferulic, cinnamic, syringic, vanillic, 2,4-dihydroxybenzoic, and o-coumaric acids and syringaldehyde. Phenolic acids were mostly found as bound compounds. Significant varietal differences ( p phenolic acids, with the lowest level found in cv. 'Viviana' (1202 ± 52.9 mg kg -1 ) and the highest in cv. 'Akseli' (1687 ± 80.2 mg kg -1 ). Avenanthramides (AVNs) 2a, 2p, and 2f were the most abundant. Total AVNs levels ranged from 26.7 ± 1.44 to 185 ± 12.5 mg kg -1 in cv. 'Avetron' and 'Viviana', respectively.

Improving phenolic bioactive-linked anti-hyperglycemic functions of dark germinated barley sprouts (Hordeum vulgare L.) using seed elicitation strategy.

Science.gov (United States)

Ramakrishna, Ramnarain; Sarkar, Dipayan; Manduri, Avani; Iyer, Shreyas Ganesan; Shetty, Kalidas

2017-10-01

Sprouts of cereal grains, such as barley ( Hordeum vulgare L.), are a good source of beneficial phenolic bioactives. Such health relevant phenolic bioactives of cereal sprouts can be targeted to manage chronic hyperglycemia and oxidative stress commonly associated with type 2 diabetes (T2D). Therefore improving phenolic bioactives by stimulating plant endogenous defense responses such as protective pentose phosphate pathway (PPP) during sprouting has significant merit. Based on this metabolic rationale, this study aimed to enhance phenolic bioactives and associated antioxidant and anti-hyperglycemic functions in dark germinated barley sprouts using exogenous elicitor treatments. Dark-germinated sprouts of two malting barley cultivars (Pinnacle and Celebration), treated with chitosan oligosaccharide (COS) and marine protein hydrolysate (GP), were evaluated. Total soluble phenolic content (TSP), phenolic acid profiles, total antioxidant activity (TA) and in vitro inhibitory activities of hyperglycemia relevant α-amylase and α-glucosidase enzymes of the dark germinated barley sprouts were evaluated at day 2, 4, and 6 post elicitor treatments. Overall, TSP content, TA, and α-amylase inhibitory activity of dark germinated barley sprouts decreased, while α-glucosidase inhibitory activity and gallic acid content increased from day 2 to day 6. Among barley cultivars, high phenolic antioxidant-linked anti-hyperglycemic bioactives were observed in Celebration. Furthermore, GP and COS seed elicitor treatments in selective doses improved T2D relevant phenolic-linked anti-hyperglycemic bioactives of barley spouts at day 6. Therefore, such seed elicitation approach can be strategically used to develop bioactive enriched functional food ingredients from cereal sprouts targeting chronic hyperglycemia and oxidative stress linked to T2D.

Production of cinnamic and p-hydroxycinnamic acids in engineered microbes

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Alejandra eVargas-Tah

2015-08-01

Full Text Available The aromatic compounds cinnamic and p-hydroxycinnamic acids are phenylpropanoids having applications as precursors for the synthesis of thermoplastics, flavoring, cosmetic and health products. These two aromatic acids can be obtained by chemical synthesis or extraction from plant tissues. However, both manufacturing processes have shortcomings such as the generation of toxic subproducts or a low concentration in plant material. Alternative production methods are being developed to enable the biotechnological production of cinnamic and p-hydroxycinnamic acids by genetically engineering various microbial hosts, including Escherichia coli, Saccharomyces cerevisiae, Pseudomonas putida and Streptomyces lividans. The natural capacity to synthesize these aromatic acids is not existent in these microbial species. Therefore, genetic modification have been performed that include the heterologous expression of genes encoding phenylalanine ammonia-lyase and tyrosine ammonia-lyase activities, which catalyze the conversion of L-phenylalanine and L-tyrosine to cinnamic acid and p-hydroxycinnamic acid, respectively. Additional host modifications include the metabolic engineering to increase carbon flow from central metabolism to the L-phenylalanine or L-tyrosine biosynthetic pathways. These strategies include the expression of feedback insensitive mutant versions of enzymes from the aromatic pathways, as well as genetic modifications to central carbon metabolism to increase biosynthetic availability of precursors phosphoenolpyruvate and erythrose-4-phosphate. These efforts have been complemented with strain optimization for the utilization of raw material, including various simple carbon sources, as well as sugar polymers and sugar mixtures derived from plant biomass. A systems biology approach to production strains characterization has been limited so far and should yield important data for future strain improvement.

Effect of maceration duration on physicochemical characteristics, organic acid, phenolic compounds and antioxidant activity of red wine from Vitis vinifera L. Karaoglan.

Science.gov (United States)

Kocabey, N; Yilmaztekin, M; Hayaloglu, A A

2016-09-01

Effects of different maceration times (5, 10 and 15 days) on composition, phenolic compounds and antioxidant activities of red wines made from the Vitis vinifera L. Karaoglan grown in Malatya were investigated. Maceration duration changed some chemical constituents and color of Karaoglan red wines. A linear relationship was observed between antioxidant activity of wine and maceration duration. Major organic acid was tartaric acid which was at the highest concentration in wine macerated for 10 days. A total of 25 phenolic compounds was determined in wine samples. Within these phenolics; procyanidin B2, trans -caftaric acid, gallic acid, trans -caffeic acid, (+) catechin, (-) epicatechin and quercetin-3- O -glucoside were the most abundant phenolics regardless of maceration duration. In general, extended maceration duration resulted in increase in the concentration of phenolic compounds, reflecting the antioxidant activities of wine. In conclusion, the highest concentrations of total and individual phenolic compounds as well as antioxidant activities were found in wines macerated for 15 days.

INVESTIGATION OF PHENOLIC COMPOUNDS IN EXTRACTS FROM THE LEAVES OF LAURUS NOBILIS L.

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N. M. Nasuhova

2017-01-01

Full Text Available Laurus nobilis L. is an evergreen dioecious, rarely monecious plant up to 15 m high. Its natural area includes Mediterranean countries. For a long time this plant has been actively cultivated as a decorative plant in (Europe, Russia, USA and others as well as in Turkey, Algeria, Morocco, Spain, France, Italy, Portugal, Mexico and Russia. Chemical composition of the Laurus leaves include essential oil components, sesquiterpenic lactones and phenolic compounds as the principal active groups of compounds.The aim of the study was the identification of phenolic compounds in water and water alcohol extracts from leaves of Laurus nobilis.Materials and methods. Examinations of qualitative composition of phenolic complex in extracts from Laurus samples under study were carried out using «Hitachi Chromaster» high-performance liquid chromatographer with «Column Oven 5310», «Pump 5110» and «UV-detector 5410».Results and discussion. The samples of Laurus nobilis leaves gathered in outskirts of Alushta (Republic of Crimea in July 2016 were the objects if the study. We identified caffeic, gallic, and chicoric acids, epigallocatechin gallate, luteolin-7-glycoside in the extracts obtained using ethanol 70%. And caffeic, gallic, isoferulic acids, dicoumarin, epicatechin, kaempferol, and isoquercitrin in ethanol 40% extracts. In water extracts we found the presence of ascorbic, gallic, and vanillic acids, epicatechin, quercetin-3-glycoside and kaempferol-3-galactoside.Conclusion. As the result of the Laurus nobilis leaves samples study, gathered in Alushta outskirts, ascorbic acid and 13 phenolic compounds were identified in water and water-alcohol (40% and 70% extracts using high performance liquid chromatography. Isoferulic and chicoric acids, epigallocatechin gallate, dicoumarin, kaempferol, isoquercitrin, kaempferol-3-galactoside and luteolin-7-glycoside were identified in Laurus nobilis leaves for the first time. 

Effects of γ-Irradiation of Wild Thyme (Thymus serpyllum L. on the Phenolic Compounds Profile of Its Ethanolic Extract

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Janiak Michał A.

2017-12-01

Full Text Available The presented study revealed that there were changes in the phenolic compounds profile of extract of wild thyme (Thymus serpyllum L. after γ-irradiation at the dose of 5 kGy. Ethanolic extracts of irradiated and non-irradiated herb were prepared and their compounds were analyzed by RP-HPLC-DAD technique. Between thirty two detected constituents, twelve phenolic compounds classified as hydroxybenzoic and hydroxycinnamic acids derivatives, flavones and flavanones were identified. Among them, caffeic acid derivatives and flavones predominated with the highest content of rosmarinic acid and luteolin-7-O-glucoside, respectively. Additionally, thymol was recognized in the analyzed extracts. γ-Irradiation slightly affected the quantitative profile of phenolic compounds of a wild thyme ethanolic extract. Only four constituents differed significantly (P<0.05 in terms of their content in the irradiated and non-irradiated samples. The content of phenolic acids (p-coumaric and caffeic acids decreased and that of flavonoid aglycons (luteolin and eriodictyol increased after the γ-ray treatment.

Vanillin production by biotransformation of phenolic compounds in fungus, Aspergillus luchuensis.

Science.gov (United States)

Taira, Junsei; Toyoshima, Rin; Ameku, Nana; Iguchi, Akira; Tamaki, Yasutomo

2018-03-13

Vanillin is valuable and popular flavor used in foods and cosmetics. Many bacteria species have the ability to decarboxylate substituted cinnamic acids in order to form vanillin. However, the phenolic biotransformation including vanillin production in a common fungus, the Aspergillus luchuensis, which is used in distilled beverages, has not yet been clarified. This study focused on elucidating the vanillin production due to phenolic biotransformation in A. luchuensis during fermentation. The phenolic metabolites were extracted by a solid phase column and they were determined using on LC/MS and LC/MS/MS in a selective ion mode. As a result, ferulic acid, vanillin and vanillic acid, were detected in the rice koji fermentationed by A. luchuensis and also fermentated with yeast. In addition, the accurate molecular formula of vanillin glucoside (C 14 H 17 O 8 , 313.0927, (M-H) - and its production ions was also determined by HRESI-mass spectrometry. Based on the results including the phenolic metabolites and related genes found in A. luchuensis genome, this study proposed the vanillin production mechanism due to the side chain cleavage of ferulic acid through Coenzyme A (CoA) and feruloyl-CoA hydratase/lyase, to form vanillin and acetyl-COA. In this study, another possible vanillin production pathway also was proposed due to the neutral hexose hydrolysis of vanillin glucoside. The subsequent dehydrogenation of vanillin produced vanillic acid. In addition, vanillin was detected in the distilled alcohol indicating its contribution to the aroma profile of beverages. It has been unknown that the vanillin in the distilled solution is derived from the vanillin produced during rice-koji and/or moromi mash fermentations.

Phenolic acids as bioindicators of fly ash deposit revegetation.

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Djurdjević, L; Mitrović, M; Pavlović, P; Gajić, G; Kostić, O

2006-05-01

The floristic composition, the abundance, and the cover of pioneer plant species of spontaneously formed plant communities and the content of total phenolics and phenolic acids, as humus constituents, of an ash deposit after 7 years of recultivation were studied. The restoration of both the soil and the vegetation on the ash deposits of the "Nikola Tesla-A" thermoelectric power plant in Obrenovac (Serbia) is an extremely slow process. Unfavorable physical and chemical characteristics, the toxicity of fly ash, and extreme microclimatic conditions prevented the development of compact plant cover. The abundance and cover of plants increased from the central part of the deposit towards its edges (ranging from 1-80%). Festuca rubra L., Crepis setosa Hall., Erigeron canadensis L., Cirsium arvense (L.) Scop., Calamagrostis epigeios (L.) Roth., and Tamarix gallica L. were the most abundant species, thus giving the highest cover. Humus generated during the decomposition process of plant remains represents a completely new product absent in the ash as the starting material. The amount of total phenolics and phenolic acids (38.07-185.16 microg/g of total phenolics and 4.12-27.28 microg/g of phenolic acids) in fly ash increased from the center of the deposit towards its edges in correlation with the increase in plant abundance and cover. Ash samples contained high amounts of ferulic, vanillic, and p-coumaric acid, while the content of both p-hydroxybenzoic and syringic acid was relatively low. The presence of phenolic acids indicates the ongoing process of humus formation in the ash, in which the most abundant pioneer plants of spontaneously formed plant communities play the main role. Phenolic compounds can serve as reliable bioindicators in an assessment of the success of the recultivation process of thermoelectric power plants' ash deposits.

Effect of {sup 60}Co gamma radiation on the levels of phenolic compounds from crude extracts of bark of Spondias luta L

Energy Technology Data Exchange (ETDEWEB)

Santos, Gustavo H.F.; Silva, Hianna A.M.F.; Melo, Mychely S., E-mail: santosghf@hotmail.com, E-mail: hiannaamfs@gmail.com, E-mail: mychely.melo@gmail.com [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil); Silva, Edvane B., E-mail: edvborges@yahoo.com [Universidade Federal de Pernambuco (UFPE), Vitoria de Santo Antao, PE (Brazil). Centro Academinco de Vitoria

2013-07-01

Spondias luta L. (Anacardiaceae), popularly known as cajazeira, is a plant widespread in several regions of Brazil, famous for containing phenolic compounds, which are responsible for your characteristic astringent. Ionizing radiations have the ability to cross the material, ionizing atoms and molecules, causing changes in atoms and molecules important. It is known ionizing radiation promotes quantitative and qualitative changes in plant materials, increasing, decreasing or inactivating secondary substances. The objective of this work was to evaluate the effect of gamma radiation as a modifier of the activity of the phenolic compounds of the bark extract of S. luta L. Methods: For the dosage of phenol extracts (control, irradiated with 5 kGy, 10 kGy, 15 kGy and 20 kGy) were diluted in methanol to a final concentration of 200 mg / L. In test tubes were added 50 μL of extract plus 1 ml of distilled water and 500 μl of Folin (diluted 1:10). After 10 minutes in a dark chamber was added 2.5 ml of calcium carbonate to 20% and the content of the tube was homogenized. After 20 minutes was performed with a spectrophotometer at 735 nm. The assay was performed in triplicate and calculated from a standard curve solution of gallic acid and expressed in μEAG (GAE/mg extract). Results: The control extracts, irradiated to 5 kGy, 10 kGy, 15 kGy and 20 kGy, had, respectively, 6.25, 6.70, 6.25, 6.85, 6.45 μEAG/mg of extract. Conclusion: The results showed no significant change in the amount of phenolic compounds, showing that these compounds are radioresistant extract these doses. (author)

In vitro antimicrobial activity of Pistacia lentiscus L. edible oil and phenolic extract.

Science.gov (United States)

Mezni, F; Aouadhi, C; Khouja, M L; Khaldi, A; Maaroufi, A

2015-01-01

Pistacia lentiscus L. is known in some Tunisian forest area by its fixed oil used in traditional medicine as an antiseptic product. This investigation is the first to study the antimicrobial activity of P.lentiscus edible oil and its phenolic extract. Oil was extracted from fruits harvested from six provenances located in Tunisia. The antimicrobial activity was tested using disc diffusion assay and the broth dilution method. Kbouch and Sidi Zid oils were most efficient (p oil and extract.

Standardized uptake value and quantification of metabolism for breast cancer imaging with FDG and L-[1-C-11]tyrosine PET

NARCIS (Netherlands)

Kole, AC; Nieweg, OE; Pruim, J; Paans, AMJ; Plukker, JTM; Hoekstra, HJ; Vaalburg, W; Schraffordt Koops, H.

The aims of the study were to compare the value of L-[1-C-11]tyrosine (TYR) and [F-18]fluoro-2-deoxy-D-glucose (FDG) as tumor tracers in patients with breast cancer, to investigate the correlation between quantitative values and standardized uptake values (SUVs) and to estimate the value of SUVs for

Uptake of Tyrosine Amino Acid on Nano-Graphene Oxide

Directory of Open Access Journals (Sweden)

Hossam M. Nassef

2018-01-01

Full Text Available Graphene oxide (GO is emerging as a promising nanomaterial with potential application in the detection and analysis of amino acids, DNA, enzymes, and proteins in biological fluid samples. So, the reaction of GO with amino acids should be characterized and determined before using it in biosensing methods and devices. In this study, the reaction of tyrosine amino acid (Tyr with GO was characterized using FT-IR, UV-vis spectrophotometry, and scanning electron microscopy (SEM before its use. The optimum conditions for GO’s interaction with Tyr amino acid have been studied under variable conditions. The optimum conditions of pH, temperature, shaking time, and GO and tyrosine concentrations for the uptaking of tyrosine amino acid onto the GO’s surface from aqueous solution were determined. The SEM analysis showed that the GO supplied was in a particle size range between 5.4 and 8.1 nm. A pH of 8.4–9.4 at 25 °C and 5 min of shaking time were the optimum conditions for a maximum uptake of 1.4 μg/mL of tyrosine amino acid onto 0.2 mg/mL of GO.

Fully automated one-pot radiosynthesis of O-(2-[{sup 18}F]fluoroethyl)-L-tyrosine on the TracerLab FX{sub FN} module

Energy Technology Data Exchange (ETDEWEB)

Bourdier, Thomas, E-mail: bts@ansto.gov.au [LifeSciences, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC NSW 2232, Sydney (Australia); Greguric, Ivan [LifeSciences, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC NSW 2232, Sydney (Australia); Roselt, Peter [Centre for Molecular Imaging, Peter MacCallum Cancer Centre, 12 St Andrew' s Place, East Melbourne, VIC, 3002 (Australia); Jackson, Tim; Faragalla, Jane; Katsifis, Andrew [LifeSciences, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC NSW 2232, Sydney (Australia)

2011-07-15

Introduction: An efficient fully automated method for the radiosynthesis of enantiomerically pure O-(2-[{sup 18}F]fluoroethyl)-L-tyrosine ([{sup 18}F]FET) using the GE TracerLab FX{sub FN} synthesis module via the O-(2-tosyloxyethyl)-N-trityl-L-tyrosine tert-butylester precursor has been developed. Methods: The radiolabelling of [{sup 18}F]FET involved a classical [{sup 18}F]fluoride nucleophilic substitution performed in acetonitrile using potassium carbonate and Kryptofix 222, followed by acid hydrolysis using 2N hydrochloric acid. Results: [{sup 18}F]FET was produced in 35{+-}5% (n=22) yield non-decay-corrected (55{+-}5% decay-corrected) and with radiochemical and enantiomeric purity of >99% with a specific activity of >90 GBq/{mu}mol after 63 min of radiosynthesis including HPLC purification and formulation. Conclusion: The automated radiosynthesis provides high and reproducible yields suitable for routine clinical use.

In vitro bioaccessibility, transepithelial transport and antioxidant activity of Urtica dioica L. phenolic compounds in nettle based food products.

Science.gov (United States)

Bonetti, Gianpiero; Tedeschi, Paola; Meca, Giuseppe; Bertelli, Davide; Mañes, Jordi; Brandolini, Vincenzo; Maietti, Annalisa

2016-10-12

Nettle (Urtica dioica L.) is a well-known plant with a wide historical background use of stems, roots and leaves. Nettle leaves are an excellent source of phenolic compounds, principally 3-caffeoylquinic acid (3-CQA), caffeoylmalic acid (CMA) and rutin. The aim of this work was to evaluate the bioaccessibility (BAC), the bioavailability (BAV) and the antioxidant activity of nettle phenolic compounds present in foods and supplements. The BAC of nettle phenolics was evaluated with an in vitro dynamic digestion of real food matrices: the type of food matrix and chemical characteristic affected the kinetics of release and solubilization, with the highest BAC after duodenal digestion. A study of duodenal trans epithelial transport evidenced low bioavailability of native forms of 3-CQA, CMA and rutin. Simulation of colonic metabolism confirmed that phenolic compounds are fermented by gut microflora, confirming the need for further investigations on the impact of phenolic compounds at the large intestine level. Photochemiluminescence assay of the simulated digestion fluids demonstrated that ingestion of Urtica based foods contributes to create an antioxidant environment against superoxide anion radicals in the entire gastrointestinal tract (GIT).

Schizosaccharomyces pombe and Saccharomyces cerevisiae yeasts in sequential fermentations: Effect on phenolic acids of fermented Kei-apple (Dovyalis caffra L.) juice.

Science.gov (United States)

Minnaar, P P; Jolly, N P; Paulsen, V; Du Plessis, H W; Van Der Rijst, M

2017-09-18

Kei-apple (Dovyalis caffra) is an evergreen tree indigenous to Southern Africa. The fruit contains high concentrations of l-malic acid, ascorbic acid, and phenolic acids. Kei-apple juice was sequentially inoculated with Schizosaccharomyces pombe and Saccharomyces cerevisiae yeasts. A reference fermentation using only S. cerevisiae was included. The fermentation was monitored by recording mass loss. At the end of fermentation, twelve untrained judges conducted free choice aroma profiling on the fruit wines. The Kei-apple juice and wines were analysed for total titratable acidity, total soluble solids, pH, alcohol, l-malic acid, and phenolic acids. Total titratable acidity was ca. 70% lower in Kei-apple wines produced with S. pombe+S. cerevisiae than in Kei-apple juice. Kei-apple wines produced with S. pombe+S. cerevisiae showed substantially lower concentrations of l-malic acid than Kei-apple wines produced with S. cerevisiae only. Wines produced with S. cerevisiae only proved higher in phenolic acid concentrations than wines produced with S. pombe+S. cerevisiae. Chlorogenic acid was the most abundant phenolic acid measured in the Kei-apple wines, followed by protocatechuic acid. Judges described the Kei-apple wines produced with S. pombe+S. cerevisiae as having noticeable off-odours, while wines produced with S. cerevisiae were described as fresh and fruity. Kei-apple wines (S. pombe+S. cerevisiae and S. cerevisiae) were of comparable vegetative and organic character. Saccharomyces cerevisiae produced Kei-apple wine with increased caffeic, chlorogenic, protocatechuic, and sinapic acids, whereas S. pombe+S. cerevisiae produced Kei-apple wines with increased ferulic, and p-coumaric acids and low l-malic acid. Copyright © 2017 Elsevier B.V. All rights reserved.

Xylella fastidiosa esterase rather than hydroxynitrile lyase.

Science.gov (United States)

Torrelo, Guzman; Ribeiro de Souza, Fayene Zeferino; Carrilho, Emanuel; Hanefeld, Ulf

2015-03-02

In 2009, we reported that the product of the gene SCJ21.16 (XFa0032) from Xylella fastidiosa, a xylem-restricted plant pathogen that causes a range of diseases in several important crops, encodes a protein (XfHNL) with putative hydroxynitrile lyase activity. Sequence analysis and activity tests indicated that XfHNL exhibits an α/β-hydrolase fold and could be classified as a member of the family of FAD-independent HNLs. Here we provide a more detailed sequence analysis and new experimental data. Using pure heterologously expressed XfHNL we show that this enzyme cannot catalyse the cleavage/synthesis of mandelonitrile and that this protein is in fact a non-enantioselective esterase. Homology modelling and ligand docking simulations were used to study the active site and support these results. This finding could help elucidate the common ancestor of esterases and hydroxynitrile lyases with an α/β -hydrolase fold. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Formation of brominated phenolic contaminants from natural manganese oxides-catalyzed oxidation of phenol in the presence of Br(.).

Science.gov (United States)

Lin, Kunde; Song, Lianghui; Zhou, Shiyang; Chen, Da; Gan, Jay

2016-07-01

Brominated phenolic compounds (BPCs) are a class of persistent and potentially toxic compounds ubiquitously present in the aquatic environment. However, the origin of BPCs is not clearly understood. In this study, we investigated the formation of BPCs from natural manganese oxides (MnOx)-catalyzed oxidation of phenol in the presence of Br(-). Experiments at ambient temperature clearly demonstrated that BPCs were readily produced via the oxidation of phenol by MnOx in the presence of Br(-). In the reaction of MnOx sand with 0.213 μmol/L phenol and 0.34 mmol/L Br(-) for 10 min, more than 60% of phenol and 56% of Br(-) were consumed to form BPCs. The yield of BPCs increased with increasing concentrations of phenol and Br(-). Overall, a total of 14 BPCs including simple bromophenols (4-bromophenol, 2,4-dibromophenol, and 2,4,6-tribromophenol), hydroxylated polybrominated diphenyl ethers (OH-PBDEs), and hydroxylated polybrominated biphenyls (OH-PBBs) were identified. The production of BPCs increased with increasing concentrations of Br(-) or phenol. It was deduced that Br(-) was first oxidized to form active bromine, leading to the subsequent bromination of phenol to form bromophenols. The further oxidation of bromophenols by MnOx resulted in the formation of OH-PBDEs and OH-PBBs. In view of the ubiquity of phenol, Br(-), and MnOx in the environment, MnOx-mediated oxidation may play a role on the natural production of BPCs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Phosphate and arsenate removal efficiency by thermostable ferritin enzyme from Pyrococcus furiosus using radioisotopes

KAUST Repository

Sevcenco, Ana-Maria

2015-03-13

Oxo-anion binding properties of the thermostable enzyme ferritin from Pyrococcus furiosus were characterized with radiography. Radioisotopes 32P and 76As present as oxoanions were used to measure the extent and the rate of their absorption by the ferritin. Thermostable ferritin proved to be an excellent system for rapid phosphate and arsenate removal from aqueous solutions down to residual concentrations at the picomolar level. These very low concentrations make thermostable ferritin a potential tool to considerably mitigate industrial biofouling by phosphate limitation or to remove arsenate from drinking water.

Catalytically important amino-acid residues of abalone alginate lyase HdAly assessed by site-directed mutagenesis

OpenAIRE

Yamamoto, Sayo; Sahara, Takehiko; Sato, Daisuke; Kawasaki, Kosei; Ohgiya, Satoru; Inoue, Akira; Ojima, Takao

2008-01-01

Alginate lyase is an enzyme that degrades alginate chains via β-elimination and has been used for the production of alginate oligosaccharides and protoplasts from brown algae. Previously, we deduced the amino-acid sequence of an abalone alginate lyase, HdAly, from its cDNA sequence and, through multiple amino-acid sequence alignment, found that several basic amino-acid residues were highly conserved among the polysaccharide-lyase family 14 (PL-14) enzymes including HdAly. In the present study...

Synthesis and characterization of L-tyrosine hydrochloride crystals submitted to high and low temperatures

Energy Technology Data Exchange (ETDEWEB)

Santos, C.A.A.S.; Facanha Filho, P.F.; Ribeiro, L.H.L.; Victor, F.M.S.; Abreu, D.C.; Santos, A.O. dos; Carvalho, J.O.; Soares, R.A.; Sousa, J.C.F.; Lima, R.C.; Cavaignac, A.O. [Universidade Federal do Maranhao (UFMA), MA (Brazil)

2016-07-01

Full text: New materials are emerging and generate advances in nonlinear optics that studies the phenomena related to changes in optical properties when occurs interaction of light with the matter. Semi organic crystals present such properties. The goal is this work is to produce semi organic single crystal of L-tyrosine hydrochloride (LTHCl) and verify their thermal stability when subjected to high and low temperatures. The single crystals of LTHCl were produced for solubilization of amino acid L-tyrosine in hydrochloric acid using slow solvent evaporation technique at a constant temperature of 25 deg C. The X-ray diffraction (XRD) and refining by the Rietveld method were used to confirm the structure of the material. The thermal stability was investigated using DSC, TGA-DTA. The LTHCl crystal belongs to the monoclinic system, with two molecules per unit cell. The refinement by the Rietveld method showed good results with Rwp= 8.49% and Rp= 6.29% with S=1.13. Thermal analysis shown an endothermic event at about 160°C, which can be associated with phase transition occurred in LTHCl crystal. It was also observed that the crystal melting point occurs at a temperature of 230°C. No water of crystallization was found in the crystal structure, which was confirmed by Raman spectroscopy and thermal analysis. From the Raman spectroscopy experiments in function of temperature, no significant changes was observe in the behavior of vibrational normal modes between temperatures of -253 and 170 deg C. Finally, a monoclinic crystal system LTHCl is stable up to 160°C at high temperatures and -253°C at low temperatures. Therefore, our investigation has proved that LTHCl crystals can be used in this range of temperature without the lost of their nonlinear optical properties. (author)

Enhancing activity and thermostability of lipase A from Serratia marcescens by site-directed mutagenesis.

Science.gov (United States)

Mohammadi, Mohsen; Sepehrizadeh, Zargham; Ebrahim-Habibi, Azadeh; Shahverdi, Ahmad Reza; Faramarzi, Mohammad Ali; Setayesh, Neda

2016-11-01

Lipases as significant biocatalysts had been widely employed to catalyze various chemical reactions such as ester hydrolysis, ester synthesis, and transesterification. Improving the activity and thermostability of enzymes is desirable for industrial applications. The lipase of Serratia marcescens belonging to family I.3 lipase has a very important pharmaceutical application in production of chiral precursors. In the present study, to achieve improved lipase activity and thermostability, using computational predictions of protein, four mutant lipases of SML (MutG2P, MutG59P, Mut H279K and MutL613WA614P) were constructed by site-directed mutagenesis. The recombinant mutant proteins were over-expressed in E. coli and purified by affinity chromatography on the Ni-NTA system. Circular dichroism spectroscopy, differential scanning calorimetry and kinetic parameters (Km and kcat) were determined. Our results have shown that the secondary structure of all lipases was approximately similar to one another. The MutG2P and MutG59P were more stable than wild type by approximately 2.3 and 2.9 in T 1/2 , respectively. The catalytic efficiency (kcat/Km) of MutH279K was enhanced by 2-fold as compared with the wild type (p<0.05). These results indicate that using protein modeling program and creating mutation, can enhance lipase activity and/or thermostability of SML and it also could be used for improving other properties of enzyme to the desired requirements as well as further mutations. Copyright © 2016 Elsevier Inc. All rights reserved.

Protein Tyrosine Nitration: Biochemical Mechanisms and Structural Basis of its Functional Effects

Science.gov (United States)

Radi, Rafael

2012-01-01

CONSPECTUS The nitration of protein tyrosine residues to 3-nitrotyrosine represents an oxidative postranslational modification that unveils the disruption of nitric oxide (•NO) signaling and metabolism towards pro-oxidant processes. Indeed, excess levels of reactive oxygen species in the presence of •NO or •NO-derived metabolites lead to the formation of nitrating species such as peroxynitrite. Thus, protein 3-nitrotyrosine has been established as a biomarker of cell, tissue and systemic “nitroxidative stress”. Moreover, tyrosine nitration modifies key properties of the amino acid (i.e. phenol group pKa, redox potential, hydrophobicity and volume). Thus, the incorporation of a nitro group (−NO2) to protein tyrosines can lead to profound structural and functional changes, some of which contribute to altered cell and tissue homeostasis. In this Account, I describe our current efforts to define 1) biologically-relevant mechanisms of protein tyrosine nitration and 2) how this modification can cause changes in protein structure and function at the molecular level. First, the relevance of protein tyrosine nitration via free radical-mediated reactions (in both peroxynitrite-dependent or independent pathways) involving the intermediacy of tyrosyl radical (Tyr•) will be underscored. This feature of the nitration process becomes critical as Tyr• can take variable fates, including the formation of 3-nitrotyrosine. Fast kinetic techniques, electron paramagnetic resonance (EPR) studies, bioanalytical methods and kinetic simulations have altogether assisted to characterize and fingerprint the reactions of tyrosine with peroxynitrite and one-electron oxidants and its further evolution to 3-nitrotyrosine. Recent findings show that nitration of tyrosines in proteins associated to biomembranes is linked to the lipid peroxidation process via a connecting reaction that involves the one-electron oxidation of tyrosine by lipid peroxyl radicals (LOO•). Second

Thermostable crude endoglucanase produced by Aspergillus ...

African Journals Online (AJOL)

Cellulases are used in many industries worldwide and there is an ever increasing need to isolate, produce or develop thermostable cellulases. Manipulation of fermentation techniques in order to obtain desirable product(s) can be one line of action. In this study Aspergillus fumigatus was grown on chopped wheat straw in a ...

Comparison of the thermostability of cellulases from various thermophilic fungi

Energy Technology Data Exchange (ETDEWEB)

Wojtczak, G; Breuil, C; Yamada, J; Saddler, J N

1987-10-01

The cellulase activities of six thermophilic fungi were compared. Although the thermophilic fungi grew at relatively high temperatures (> 45/sup 0/C) the optimum temperatures for assaying the various cellulase activities were only slightly higher than the optimum temperatures for the mesophilic fungi, Trichoderma harzianum. Over prolonged incubation (> 24 h) the thermophilic strains demonstrated a higher hydrolytic potential as a result of the greater thermostability of the cellulase components. Although the extracellular cellulase activities had similar pH and temperature optima, in some cases the thermostability of the extracellular components were considerably lower.

Do the metabolites of 6-[F-18]fluoro-L-dopa and of [F-18]fluoro-meta-L-tyrosine contribute to the F-18 accumulation in the human brain?

International Nuclear Information System (INIS)

Firnau, G.; Chirakal, R.; Nahmias, C.; Garnett, E.S.

1990-01-01

The purpose of this study was to determine if the metabolites of 6-[F-18]fluoro-L-dopa (F-dopa) and of [F-18]fluoro-meta-L-tyrosine (FmLtyr) contribute to the accumulation of fluorine-18 in the brain through unspecific retention. PET studies were conducted on a healthy human subject who was treated with both of the radiopharmaceuticals and their labelled metabolites. Results indicated that in contrast to F-dopa, the metabolite of FmLtyr does not 'contaminate' the brain with extraneous fluorine-18

Effect of cadmium on phenolic compounds, antioxidant enzyme activity and oxidative stress in blueberry (Vaccinium corymbosum L.) plantlets grown in vitro.

Science.gov (United States)

Manquián-Cerda, K; Escudey, M; Zúñiga, G; Arancibia-Miranda, N; Molina, M; Cruces, E

2016-11-01

Cadmium (Cd(2+)) can affect plant growth due to its mobility and toxicity. We evaluated the effects of Cd(2+) on the production of phenolic compounds and antioxidant response of Vaccinium corymbosum L. Plantlets were exposed to Cd(2+) at 50 and 100µM for 7, 14 and 21 days. Accumulation of malondialdehyde (MDA), hydrogen peroxide (H2O2) and the antioxidant enzyme SOD was determined. The profile of phenolic compounds was evaluated using LC-MS. The antioxidant activity was measured using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and the ferric reducing antioxidant power test (FRAP). Cd(2+) increased the content of MDA, with the highest increase at 14 days. The presence of Cd(2+) resulted in changes in phenolic compounds. The main phenolic compound found in blueberry plantlets was chlorogenic acid, whose abundance increased with the addition of Cd(2+) to the medium. The changes in the composition of phenolic compounds showed a positive correlation with the antioxidant activity measured using FRAP. Our results suggest that blueberry plantlets produced phenolic compounds with reducing capacity as a selective mechanism triggered by the highest activity of Cd(2+). Copyright © 2016 Elsevier Inc. All rights reserved.

First principles calculations for interaction of tyrosine with (ZnO)3 cluster

Science.gov (United States)

Singh, Satvinder; Singh, Gurinder; Kaura, Aman; Tripathi, S. K.

2018-04-01

First Principles Calculations have been performed to study interactions of Phenol ring of Tyrosine (C6H5OH) with (ZnO)3 atomic cluster. All the calculations have been performed under the Density Functional Theory (DFT) framework. Structural and electronic properties of (ZnO)3/C6H5OH have been studied. Gaussian basis set approach has been adopted for the calculations. A ring type most stable (ZnO)3 atomic cluster has been modeled, analyzed and used for the calculations. The compatibility of the results with previous studies has been presented here.

Overeating Behavior and Striatal Dopamine with 6-[18F]-Fluoro-L--Tyrosine PET

Directory of Open Access Journals (Sweden)

Claire E. Wilcox

2010-01-01

Full Text Available Eating behavior may be affected by dopamine synthesis capacity. In this study, 6-[18F]-fluoro-L--tyrosine (FMT positron emission tomography (PET uptake in striatal subregions was correlated with BMI (kg/m2 and an estimate of the frequency of prior weight loss attempts in 15 healthy subjects. BMI was negatively correlated with FMT uptake in the dorsal caudate. Although the association between BMI and FMT uptake in the dorsal caudate was not significant upon correction for age and sex, the association fell within the range of a statistical trend. Weight loss attempts divided by years trying was also negatively correlated with FMT uptake in the dorsal putamen (=.05. These results suggest an association between low dorsal striatal presynaptic dopamine synthesis capacity and overeating behavior.

EFFECTS OF CHANGING THE INTERACTION BETWEEN SUBDOMAINS ON THE THERMOSTABILITY OF BACILLUS NEUTRAL PROTEASES

NARCIS (Netherlands)

EIJSINK, VGH; VRIEND, G; VANDERVINNE, B; HAZES, B; VANDENBURG, B; VENEMA, G

1992-01-01

Variants of the thermolabile neutral protease (Npr) of B. subtilis (Npr-sub) and the thermostable neutral protease of B. stearothermophilus (Npr-ste) were produced by means of site-directed mutagenesis and the effects of the mutations on thermostability were determined. Mutations were designed to

[Phenolic acid derivatives from Bauhinia glauca subsp. pernervosa].

Science.gov (United States)

Zhao, Qiao-Li; Wu, Zeng-Bao; Zheng, Zhi-Hui; Lu, Xin-Hua; Liang, Hong; Cheng, Wei; Zhang, Qing-Ying; Zhao, Yu-Ying

2011-08-01

To study the chemical constituents of Bauhinia glauca subsp. pernervosa, eleven phenolic acids were isolated from a 95% ethanol extract by using a combination of various chromatographic techniques including column chromatography over silica gel, ODS, MCI, Sephadex LH-20, and semi-preparative HPLC. By spectroscopic techniques including 1H NMR, 13C NMR, 2D NMR, and HR-ESI-MS, these compounds were identified as isopropyl O-beta-(6'-O-galloyl)-glucopyranoside (1), ethyl O-beta-(6'-O-galloyl)-glucopyranoside (2), 3, 4, 5-trimethoxyphenyl-(6'-O-galloyl)-O-beta-D-glucopyranoside (3), 3, 4, 5-trimethoxyphenyl-beta-D-glucopyranoside (4), gallic acid (5), methyl gallate (6), ethyl gallate (7), protocatechuic acid (8), 3, 5-dimethoxy-4-hydroxybenzoic acid (9), erigeside C (10) and glucosyringic acid (11). Among them, compound 1 is a new polyhydroxyl compound; compounds 2, 10, and 11 were isolated from the genus Bauhinia for the first time, and the other compounds were isolated from the plant for the first time. Compounds 6 and 8 showed significant protein tyrosine phosphatase1B (PTP1B) inhibitory activity in vitro with the IC50 values of 72.3 and 54.1 micromol x L(-1), respectively.

Thermostability in endoglucanases is fold-specific

Science.gov (United States)

2011-01-01

Background Endoglucanases are usually considered to be synergistically involved in the initial stages of cellulose breakdown-an essential step in the bioprocessing of lignocellulosic plant materials into bioethanol. Despite their economic importance, we currently lack a basic understanding of how some endoglucanases can sustain their ability to function at elevated temperatures required for bioprocessing, while others cannot. In this study, we present a detailed comparative analysis of both thermophilic and mesophilic endoglucanases in order to gain insights into origins of thermostability. We analyzed the sequences and structures for sets of endoglucanase proteins drawn from the Carbohydrate-Active enZymes (CAZy) database. Results Our results demonstrate that thermophilic endoglucanases and their mesophilic counterparts differ significantly in their amino acid compositions. Strikingly, these compositional differences are specific to protein folds and enzyme families, and lead to differences in intramolecular interactions in a fold-dependent fashion. Conclusions Here, we provide fold-specific guidelines to control thermostability in endoglucanases that will aid in making production of biofuels from plant biomass more efficient. PMID:21291533

Thermostability in endoglucanases is fold-specific

Directory of Open Access Journals (Sweden)

Wolt Jeffrey D

2011-02-01

Full Text Available Abstract Background Endoglucanases are usually considered to be synergistically involved in the initial stages of cellulose breakdown-an essential step in the bioprocessing of lignocellulosic plant materials into bioethanol. Despite their economic importance, we currently lack a basic understanding of how some endoglucanases can sustain their ability to function at elevated temperatures required for bioprocessing, while others cannot. In this study, we present a detailed comparative analysis of both thermophilic and mesophilic endoglucanases in order to gain insights into origins of thermostability. We analyzed the sequences and structures for sets of endoglucanase proteins drawn from the Carbohydrate-Active enZymes (CAZy database. Results Our results demonstrate that thermophilic endoglucanases and their mesophilic counterparts differ significantly in their amino acid compositions. Strikingly, these compositional differences are specific to protein folds and enzyme families, and lead to differences in intramolecular interactions in a fold-dependent fashion. Conclusions Here, we provide fold-specific guidelines to control thermostability in endoglucanases that will aid in making production of biofuels from plant biomass more efficient.

Phenolic acids as bioindicators of fly ash deposit revegetation

Energy Technology Data Exchange (ETDEWEB)

L. Djurdjevic; M. Mitrovic; P. Pavlovic; G. Gajic; O. Kostic [Institute for Biological Research ' Sinisa Stankovic,' Belgrade (Serbia and Montenegro). Department of Ecology

2006-05-15

The floristic composition, the abundance, and the cover of pioneer plant species of spontaneously formed plant communities and the content of total phenolics and phenolic acids, as humus constituents, of an ash deposit after 7 years of recultivation were studied. The restoration of both the soil and the vegetation on the ash deposits of the 'Nikola Tesla-A' thermoelectric power plant in Obrenovac (Serbia) is an extremely slow process. Unfavorable physical and chemical characteristics, the toxicity of fly ash, and extreme microclimatic conditions prevented the development of compact plant cover. The abundance and cover of plants increased from the central part of the deposit towards its edges. Festuca rubra L., Crepis setosa Hall., Erigeron canadensis L., Cirsium arvense (L.) Scop., Calamagrostis epigeios (L.) Roth., and Tamarix gallica L. were the most abundant species, thus giving the highest cover. Humus generated during the decomposition process of plant remains represents a completely new product absent in the ash as the starting material. The amount of total phenolics and phenolic acids in fly ash increased from the center of the deposit towards its edges in correlation with the increase in plant abundance and cover. The presence of phenolic acids indicates the ongoing process of humus formation in the ash, in which the most abundant pioneer plants of spontaneously formed plant communities play the main role. Phenolic compounds can serve as reliable bioindicators in an assessment of the success of the recultivation process of thermoelectric power plants' ash deposits.

Osmotic membrane bioreactor for phenol biodegradation under continuous operation

Energy Technology Data Exchange (ETDEWEB)

Praveen, Prashant; Loh, Kai-Chee, E-mail: chelohkc@nus.edu.sg

2016-03-15

Highlights: • Osmotic membrane bioreactor was used for phenol biodegradation in continuous mode. • Extractant impregnated membranes were used to alleviate substrate inhibition. • Phenol removal was achieved through both biodegradation and membrane rejection. • Phenol concentrations up to 2500 mg/L were treated at HRT varying in 2.8–14 h. • A biofilm removal strategy was formulated to improve bioreactor sustainability. - Abstract: Continuous phenol biodegradation was accomplished in a two-phase partitioning osmotic membrane bioreactor (TPPOMBR) system, using extractant impregnated membranes (EIM) as the partitioning phase. The EIMs alleviated substrate inhibition during prolonged operation at influent phenol concentrations of 600–2000 mg/L, and also at spiked concentrations of 2500 mg/L phenol restricted to 2 days. Filtration of the effluent through forward osmosis maintained high biomass concentration in the bioreactor and improved effluent quality. Steady state was reached in 5–6 days at removal rates varying between 2000 and 5500 mg/L-day under various conditions. Due to biofouling and salt accumulation, the permeate flux varied from 1.2–7.2 LMH during 54 days of operation, while maintaining an average hydraulic retention time of 7.4 h. A washing cycle, comprising 1 h osmotic backwashing using 0.5 M NaCl and 2 h washing with water, facilitated biofilm removal from the membranes. Characterization of the extracellular polymeric substances (EPS) through FTIR showed peaks between 1700 and 1500 cm{sup −1}, 1450–1450 cm{sup −1} and 1200–1000 cm{sup −1}, indicating the presence of proteins, phenols and polysaccharides, respectively. The carbohydrate to protein ratio in the EPS was estimated to be 0.3. These results indicate that TPPOMBR can be promising in continuous treatment of phenolic wastewater.

Single-dose, subcutaneous recombinant phenylalanine ammonia lyase conjugated with polyethylene glycol in adult patients with phenylketonuria: an open-label, multicentre, phase 1 dose-escalation trial.

Science.gov (United States)

Longo, Nicola; Harding, Cary O; Burton, Barbara K; Grange, Dorothy K; Vockley, Jerry; Wasserstein, Melissa; Rice, Gregory M; Dorenbaum, Alejandro; Neuenburg, Jutta K; Musson, Donald G; Gu, Zhonghua; Sile, Saba

2014-07-05

Phenylketonuria is an inherited disease caused by impaired activity of phenylalanine hydroxylase, the enzyme that converts phenylalanine to tyrosine, leading to accumulation of phenylalanine and subsequent neurocognitive dysfunction. Phenylalanine ammonia lyase is a prokaryotic enzyme that converts phenylalanine to ammonia and trans-cinnamic acid. We aimed to assess the safety, tolerability, pharmacokinetic characteristics, and efficacy of recombinant Anabaena variabilis phenylalanine ammonia lyase (produced in Escherichia coli) conjugated with polyethylene glycol (rAvPAL-PEG) in reducing phenylalanine concentrations in adult patients with phenylketonuria. In this open-label, phase 1, multicentre trial, single subcutaneous injections of rAvPAL-PEG were given in escalating doses (0·001, 0·003, 0·010, 0·030, and 0·100 mg/kg) to adults with phenylketonuria. Participants aged 18 years or older with blood phenylalanine concentrations of 600 μmol/L or higher were recruited from among patients attending metabolic disease clinics in the USA. The primary endpoints were safety and tolerability of rAvPAL-PEG. Secondary endpoints were the pharmacokinetic characteristics of the drug and its effect on concentrations of phenylalanine. Participants and investigators were not masked to assigned dose group. This study is registered with ClinicalTrials.gov, number NCT00925054. 25 participants were recruited from seven centres between May 6, 2008, and April 15, 2009, with five participants assigned to each escalating dose group. All participants were included in the safety population. The most frequently reported adverse events were injection-site reactions and dizziness, which were self-limited and without sequelae. Two participants had serious adverse reactions to intramuscular medroxyprogesterone acetate, a drug that contains polyethylene glycol as an excipient. Three of five participants given the highest dose of rAvPAL-PEG (0·100 mg/kg) developed a generalised skin rash

Catalytic Ozonation of Phenolic Wastewater: Identification and Toxicity of Intermediates

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Mahdi Farzadkia

2014-01-01

Full Text Available A new strategy in catalytic ozonation removal method for degradation and detoxification of phenol from industrial wastewater was investigated. Magnetic carbon nanocomposite, as a novel catalyst, was synthesized and then used in the catalytic ozonation process (COP and the effects of operational conditions such as initial pH, reaction time, and initial concentration of phenol on the degradation efficiency and the toxicity assay have been investigated. The results showed that the highest catalytic potential was achieved at optimal neutral pH and the removal efficiency of phenol and COD is 98.5% and 69.8%, respectively. First-order modeling demonstrated that the reactions were dependent on the initial concentration of phenol, with kinetic constants varying from 0.038 min−1  ([phenol]o = 1500 mg/L to 1.273 min−1 ([phenol]o = 50 mg/L. Bioassay analysis showed that phenol was highly toxic to Daphnia magna (LC50 96 h=5.6 mg/L. Comparison of toxicity units (TU of row wastewater (36.01 and the treated effluent showed that TU value, after slightly increasing in the first steps of ozonation for construction of more toxic intermediates, severely reduced at the end of reaction (2.23. Thus, COP was able to effectively remove the toxicity of intermediates which were formed during the chemical oxidation of phenolic wastewaters.

Toxicities of triclosan, phenol, and copper sulfate in activated sludge.

Science.gov (United States)

Neumegen, Rosalind A; Fernández-Alba, Amadeo R; Chisti, Yusuf

2005-04-01

The effect of toxicants on the BOD degradation rate constant was used to quantitatively establish the toxicity of triclosan, phenol, and copper (II) against activated sludge microorganisms. Toxicities were tested over the following ranges of concentrations: 0-450 mg/L for phenol, 0-2 mg/L for triclosan, and 0-35 mg/L for copper sulfate (pentahydrate). According to the EC(50) values, triclosan was the most toxic compound tested (EC(50) = 1.82 +/- 0.1 mg/L), copper (II) had intermediate toxicity (EC(50) = 18.3 +/- 0.37 mg/L), and phenol was the least toxic (EC(50) = 270 +/- 0.26 mg/L). The presence of 0.2% DMSO had no toxic effect on the activated sludge. The toxicity evaluation method used was simple, reproducible, and directly relevant to activated sludge wastewater treatment processes.

Recovery of UAPB from high organic load during startup for phenolic wastewater treatment

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Bakhshi Zeinab

2011-01-01

Full Text Available Biodegradation of synthetic wastewater containing phenol by upflow anaerobic packed bed reactor (UAPB was studied in this work. The reactor was operated at a hydraulic retention time (HRT of 24 h and under mesophilic (30±1ºC conditions. The startup operation was conducted for 150 days; split into 4 phases. The phenol concentration was stepwise increased. The concentration of phenol in phases 1, 2, 3 and 4 were 100, 400, 700 and 1000 mg/l, respectively. In phase 1, the reactor reached steady state conditions on the 8th day with a phenol removal efficiency and biogas production rate of 96.8% and 1.42 l/d, respectively. For an increase of the initial phenol concentration in phase 2, a slight decrease in phenol removal efficiency was observed. Similar trends were observed in phases 3 and 4 of startup. Due to the high phenol concentration a sudden decrease in removal efficiency and biogas production was observed. The surviving microorganisms were gradually adapted and acclimated to high phenol concentrations. In phases 3 and 4, the phenol removal efficiency at steady state conditions were 98.4 and 98%, respectively. The maximum biogas production was observed at day 130 with a value of 3.57 l/d that corresponds to phenol concentration of 1000 mg/l.

Hematopoietic Sphingosine 1-Phosphate Lyase Deficiency Decreases Atherosclerotic Lesion Development in LDL-Receptor Deficient Mice

NARCIS (Netherlands)

Bot, Martine; Van Veldhoven, Paul P.; de Jager, Saskia C. A.; Johnson, Jason; Nijstad, Niels; Van Santbrink, Peter J.; Westra, Marijke M.; Van Der Hoeven, Gerd; Gijbels, Marion J.; Mueller-Tidow, Carsten; Varga, Georg; Tietge, Uwe J. F.; Kuiper, Johan; Van Berkel, Theo J. C.; Nofer, Jerzy-Roch; Bot, Ilze; Biessen, Erik A. L.

2013-01-01

Aims: Altered sphingosine 1-phosphate (S1P) homeostasis and signaling is implicated in various inflammatory diseases including atherosclerosis. As S1P levels are tightly controlled by S1P lyase, we investigated the impact of hematopoietic S1P lyase (Sgpl1(-/-)) deficiency on leukocyte subsets

Hematopoietic sphingosine 1-phosphate lyase deficiency decreases atherosclerotic lesion development in LDL-receptor deficient mice

NARCIS (Netherlands)

Bot, Martine; van Veldhoven, Paul P.; de Jager, Saskia C. A.; Johnson, Jason; Nijstad, Niels; van Santbrink, Peter J.; Westra, Marijke M.; van der Hoeven, Gerd; Gijbels, Marion J.; Müller-Tidow, Carsten; Varga, Georg; Tietge, Uwe J. F.; Kuiper, Johan; van Berkel, Theo J. C.; Nofer, Jerzy-Roch; Bot, Ilze; Biessen, Erik A. L.

2013-01-01

Altered sphingosine 1-phosphate (S1P) homeostasis and signaling is implicated in various inflammatory diseases including atherosclerosis. As S1P levels are tightly controlled by S1P lyase, we investigated the impact of hematopoietic S1P lyase (Sgpl1(-/-)) deficiency on leukocyte subsets relevant to

Electrochemical catalytic treatment of phenol wastewater

International Nuclear Information System (INIS)

Ma Hongzhu; Zhang Xinhai; Ma Qingliang; Wang Bo

2009-01-01

The slurry bed catalytic treatment of contaminated water appears to be a promising alternative for the oxidation of aqueous organic pollutants. In this paper, the electrochemical oxidation of phenol in synthetic wastewater catalyzed by ferric sulfate and potassium permanganate adsorbed onto active bentonite in slurry bed electrolytic reactor with graphite electrode has been investigated. In order to determine the optimum operating condition, the orthogonal experiments were devised and the results revealed that the system of ferric sulfate, potassium permanganate and active bentonite showed a high catalytic efficiency on the process of electrochemical oxidation phenol in initial pH 5. When the initial concentration of phenol was 0.52 g/L (the initial COD 1214 mg/L), up to 99% chemical oxygen demand (COD) removal was obtained in 40 min. According to the experimental results, a possible mechanism of catalytic degradation of phenol was proposed. Environmental estimation was also done and the results showed that the treated wastewater have little impact on plant growth and could totally be applied to irrigation.

Electrochemical catalytic treatment of phenol wastewater

Energy Technology Data Exchange (ETDEWEB)

Ma Hongzhu, E-mail: hzmachem@snnu.edu.cn [Institute of Energy Chemistry, School of Chemistry and Materials Science, Shaanxi Normal University, Xi' an 710062 (China); Zhang Xinhai [Institute of Energy Chemistry, School of Chemistry and Materials Science, Shaanxi Normal University, Xi' an 710062 (China); Ma Qingliang [Department of Applied Physics, College of Sciences, Taiyuan University of Technology, 030024 Taiyuan (China); Wang Bo [Institute of Energy Chemistry, School of Chemistry and Materials Science, Shaanxi Normal University, Xi' an 710062 (China)

2009-06-15

The slurry bed catalytic treatment of contaminated water appears to be a promising alternative for the oxidation of aqueous organic pollutants. In this paper, the electrochemical oxidation of phenol in synthetic wastewater catalyzed by ferric sulfate and potassium permanganate adsorbed onto active bentonite in slurry bed electrolytic reactor with graphite electrode has been investigated. In order to determine the optimum operating condition, the orthogonal experiments were devised and the results revealed that the system of ferric sulfate, potassium permanganate and active bentonite showed a high catalytic efficiency on the process of electrochemical oxidation phenol in initial pH 5. When the initial concentration of phenol was 0.52 g/L (the initial COD 1214 mg/L), up to 99% chemical oxygen demand (COD) removal was obtained in 40 min. According to the experimental results, a possible mechanism of catalytic degradation of phenol was proposed. Environmental estimation was also done and the results showed that the treated wastewater have little impact on plant growth and could totally be applied to irrigation.

Metabolism of Fructophilic Lactic Acid Bacteria Isolated from the Apis mellifera L. Bee Gut: Phenolic Acids as External Electron Acceptors

Science.gov (United States)

Filannino, Pasquale; Addante, Rocco; Pontonio, Erica; Gobbetti, Marco

2016-01-01

ABSTRACT Fructophilic lactic acid bacteria (FLAB) are strongly associated with the gastrointestinal tracts (GITs) of Apis mellifera L. worker bees due to the consumption of fructose as a major carbohydrate. Seventy-seven presumptive lactic acid bacteria (LAB) were isolated from GITs of healthy A. mellifera L. adults, which were collected from 5 different geographical locations of the Apulia region of Italy. Almost all of the isolates showed fructophilic tendencies: these isolates were identified as Lactobacillus kunkeei (69%) or Fructobacillus fructosus (31%). A high-throughput phenotypic microarray targeting 190 carbon sources was used to determine that 83 compounds were differentially consumed. Phenotyping grouped the strains into two clusters, reflecting growth performance. The utilization of phenolic acids, such as p-coumaric, caffeic, syringic, or gallic acids, as electron acceptors was investigated in fructose-based medium. Almost all FLAB strains showed tolerance to high phenolic acid concentrations. p-Coumaric acid and caffeic acid were consumed by all FLAB strains through reductases or decarboxylases. Syringic and gallic acids were partially metabolized. The data collected suggest that FLAB require external electron acceptors to regenerate NADH. The use of phenolic acids as external electron acceptors by the 4 FLAB showing the highest phenolic acid reductase activity was investigated in glucose-based medium supplemented with p-coumaric acid. Metabolic responses observed through a phenotypic microarray suggested that FLAB may use p-coumaric acid as an external electron acceptor, enhancing glucose dissimilation but less efficiently than other external acceptors such as fructose or pyruvic acid. IMPORTANCE Fructophilic lactic acid bacteria (FLAB) remain to be fully explored. This study intends to link unique biochemical features of FLAB with their habitat. The quite unique FLAB phenome within the group lactic acid bacteria (LAB) may have practical relevance

Antioxidant Activities of Total Phenols of Prunella vulgaris L. in Vitro and in Tumor-bearing Mice

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Feng Shi

2010-12-01

Full Text Available Prunella vulgaris L. (PV, Labiatae is known as a self-heal herb. The different extracts of dried spikes were studied for the best antioxidant active compounds. The 60% ethanol extract (P-60 showed strong antioxidant activity based on the results of 2,2’-azino-di(3-ethylbenzthiazoline-6-sulfonic acid (ABTS˙+, 2,2-diphenyl-1-picrylhydrazyl (DPPH and ferric reducing antioxidant power (FRAP assay methods. High performance liquid chromatography (HPLC and LC/MS analysis showed that the main active compounds in P-60 were phenols, such as caffeic acid, rosmarinic acid, rutin and quercetin. Total phenols were highly correlated with the antioxidant activity (R2 = 0.9988 in ABTS˙+; 0.6284 in DPPH and 0.9673 FRAP tests. P-60 could inhibit significantly the tumor growth in C57BL/6 mice. It can also been showed that increased superoxide dismutase (SOD activity and decreased malondialdehyde (MDA content in serum of tumor-bearing mice. These results suggested that P-60 extract had high antioxidant activity in vitro and in vivo and total phenols played an important role in antioxidant activity for inhibition of tumor growth.

Lag phase and biomass determination of Rhodococcus pyridinivorans GM3 for degradation of phenol

Science.gov (United States)

Al-Defiery, M. E. J.; Reddy, G.

2018-05-01

Among various techniques available for removal of phenol, biodegradation is an eco-friendly and cost effective method. Thus, it is required to understand the process of biodegradation of phenol, such as investigate on lag phase and biomass concentration. Phenol degrading bacteria were isolated from soil samples of industrial sites in enriched mineral salts medium (MSM) with phenol as a sole source of energy and carbon. One isolate of potential phenol degradation from consortium for phenol degrading studies was identified as Rhodococcus pyridinivorans GM3. Lag phase and biomass determination of R. pyridinivorans GM3 was studied with different phenol concentrations under pH 8.5 at temperature 32 Co and 200 rpm. Microbial biomass was directly proportional to increasing phenol concentration between 1.0 to 2.0 g/L with a maximum dry biomass of 1.745 g/L was noted after complete degradation of 2.0 g/L phenol in 48 hours.

Influence of Different Fermentation Strategies on the Phenolic Profile of Bilberry Wine (Vaccinium myrtillus L.).

Science.gov (United States)

Behrends, Annika; Weber, Fabian

2017-08-30

Polyphenol rich and especially anthocyanin rich berries like bilberries (Vaccinium myrtillus L.) and derived products such as wine have enjoyed increasing popularity. During winemaking and aging, the phenolic profile undergoes distinct changes, a phenomenon that has been well investigated in grape wine but not in bilberry wine. The present study determined the influence of different fermentation strategies including various pre- and postfermentative heating and cooling concepts on the phenolic profile of bilberry wine. Besides significant differences in total anthocyanin and tannin concentrations, the different fermentation strategies resulted in distinguishable anthocyanin profiles. A very fast aging manifested by a rapid decrease in monomeric anthocyanins of up to 98% during a 12 week storage and a coincident formation of polymeric pigments and pyranoanthocyanins was observed. Several well-known processes associated with production and aging of wine were much more pronounced in bilberry wine compared to grape wine.

Purification and Characterization of Thermostable Cellulase from ...

African Journals Online (AJOL)

The thermostable CMCase was purified with ion-exchange and gel filtration chromatography. Results: ... Conclusion: Due to its high temperature stability, the purified XM70-CMCase may be useful for industrial application such as biofuel, animal feed industry, paper industry and clarification of fruit juices. Keywords: ...

Phenolic compounds from the leaf extract of artichoke (Cynara scolymus L.) and their antimicrobial activities.

Science.gov (United States)

Zhu, Xianfeng; Zhang, Hongxun; Lo, Raymond

2004-12-01

A preliminary antimicrobial disk assay of chloroform, ethyl acetate, and n-butanol extracts of artichoke (Cynara scolymus L.) leaf extracts showed that the n-butanol fraction exhibited the most significant antimicrobial activities against seven bacteria species, four yeasts, and four molds. Eight phenolic compounds were isolated from the n-butanol soluble fraction of artichoke leaf extracts. On the basis of high-performance liquid chromatography/electrospray ionization mass spectrometry, tandem mass spectrometry, and nuclear magnetic resonance techniques, the structures of the isolated compounds were determined as the four caffeoylquinic acid derivatives, chlorogenic acid (1), cynarin (2), 3,5-di-O-caffeoylquinic acid (3), and 4,5-di-O-caffeoylquinic acid (4), and the four flavonoids, luteolin-7-rutinoside (5), cynaroside (6), apigenin-7-rutinoside (7), and apigenin-7-O-beta-D-glucopyranoside (8), respectively. The isolated compounds were examined for their antimicrobial activities on the above microorganisms, indicating that all eight phenolic compounds showed activity against most of the tested organisms. Among them, chlorogenic acid, cynarin, luteolin-7-rutinoside, and cynaroside exhibited a relatively higher activity than other compounds; in addition, they were more effective against fungi than bacteria. The minimum inhibitory concentrations of these compounds were between 50 and 200 microg/mL.

Hematopoietic Sphingosine 1-Phosphate Lyase Deficiency Decreases Atherosclerotic Lesion Development in LDL-Receptor Deficient Mice

NARCIS (Netherlands)

Bot, M.; Veldhoven, van P.P.; Jager, de S.C.; Johnson, J.; Nijstad, N.; van, Santbrink P.J.; Westra, M.M.; Hoeven, van der G.; Gijbels, M.J.; Muller-Tidow, C.; Varga, G.; Tietge, U.J.; Kuiper, J.; Berkel, van T.J.; Nofer, J.R.; Bot, I.; Biessen, E.A.

2013-01-01

Abstract Aims Altered sphingosine 1-phosphate (S1P) homeostasis and signaling is implicated in various inflammatory diseases including atherosclerosis. As S1P levels are tightly controlled by S1P lyase, we investigated the impact of hematopoietic S1P lyase (Sgpl1−/−) deficiency on leukocyte

Production of tyrosine through phenylalanine hydroxylation bypasses the intrinsic feedback inhibition in Escherichia coli.

Science.gov (United States)

Huang, Jin; Lin, Yuheng; Yuan, Qipeng; Yan, Yajun

2015-04-01

Tyrosine is a proteinogenic aromatic amino acid that is often used as a supplement of food and animal feed, as well as a (bio-)synthetic precursor to various pharmaceutically or industrially important molecules. Extensive metabolic engineering efforts have been made towards the efficient and cost-effective microbial production of tyrosine. Conventional strategies usually focus on eliminating intrinsic feedback inhibition and redirecting carbon flux into the shikimate pathway. In this study, we found that continuous conversion of phenylalanine into tyrosine by the action of tetrahydromonapterin (MH4)-utilizing phenylalanine 4-hydroxylase (P4H) can bypass the feedback inhibition in Escherichia coli, leading to tyrosine accumulation in the cultures. First, expression of the P4H from Xanthomonas campestris in combination with an MH4 recycling system in wild-type E. coli allowed the strain to accumulate tyrosine at 262 mg/L. On this basis, enhanced expression of the key enzymes associated with the shikimate pathway and the MH4 biosynthetic pathway resulted in the elevation of tyrosine production up to 401 mg/L in shake flasks. This work demonstrated a novel approach to tyrosine production and verified the possibility to alleviate feedback inhibition by creating a phenylalanine sink.

PHYTOCHEMICAL STUDY AND EVALUATION OF THE ANTIMICROBIAL AND ANTIOXIDANT ACTIVITY OF ESSENTIAL OILS AND PHENOLIC COMPOUNDS OF PISTACIA LENTISCUS L

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K. Arab

2014-06-01

Full Text Available This work aims for the phytochemical study and evaluation of the antioxidant activity of phenolic compounds and essential oils of medicinal plant Pistacia lentiscus L. quantitatively and qualitatively. Through the results obtained, it appears that the leaves and fruits are rich in substances with a high antioxidant power. The yield of the phenolic compounds obtained from 10g to powder of plant is for leaves 116.49 % and 61.34 % for fruit . For essential oils, it is 0.253 ± 0.131 % for 100 g of plant material. The chromatographic profile of the essential oil of Pistacia lentiscus L. shows that monoterpenes are the major compound (9.675 % of identified molecules. The strong antioxidant activity of extracts obtained only confirms the traditional use of this plant by the local population.

Phenolic compounds of ethanol extracts of Lemna minor L., Lemna trisulca L. and Lemna polyrrhiza L. Schleid and their immunomodulating activity

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Sergazy M. Adekenov

2017-01-01

Full Text Available The purpose of the study is to determine the composition of the phenolic compounds of ethanol extracts isolated from three species of duckweed: Lemna minor L., Lemna trisulca L. and Lemna polyrrhiza L. (the synonym is Spirodella polyrrhiza Schleid. and to study its effect on immune system activation.Materials and methods. The objects of the study are: air-dried grass samples of Lemna minor L., Lemna trisuica L. and Lemna polyrrhiza L. collected during their growing season in 2010–2011 in low-flow and stagnant ponds of Kozhevnikovsky and Tomsk districts of Tomsk region. Isolation of polyphenolic complexes (PFC was carried out by extraction of air-dried raw material with ethyl alcohol. In qualitative and quantitative analysis of the samples studied the method of reversed-phase high-performance liquid chromatography on an Agilent 1100 Series instrument (USA was used in isocratic mode. In the experiments, 200 male C57BL / 6 and BALB / C mice aged 8–12 weeks were used to determine immunomodulatory activity. Cell proliferation was assessed by a colorimetric method. The absorption of the obtained solutions was measured with a multi-channel spectrophotometer at the wavelength of 540 nm. The determination of antibody-forming cells in the spleen was performed by local hemolysis. The titer of antibodies in serum was evaluated in the hemagglutination reaction. The local hypersensitivity reaction of immediate type was assessed by the author’s modification.Results. For the first time the study of the qualitative composition and quantitative content of PFC of Lemna minor L. (LM , Lemna trisulca L. (LT trisulkas, and Lemna polyrrhiza L. (LP : (4,7 ± 0,4%, (3,3 ± 0,3%, (12,8 ± 0,7% was carried out. The highest content of phenolic acids (10,76% and the sum of flavonoids, isoflavonoids and coumarins (14,7% were found in the LP sample. The content of chlorogenic and 3,5-dihydroxybenzoic acids was 2–9 times higher in LP than in other species of duckweed

Chromatographic analysis of phenol compounds in six natural populations of Anthyllis vulneraria (L.

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Andzrej Kalinowski

2015-01-01

Full Text Available Thin-layer chromatography was used to study the phenol composition in individual plants from six natural populations of Anthyllis collected from three distinct geographic regions of Poland. The results showed a variability of the phenols in the examined populations. The populations from Wielkopolska region proved to be most variable, showing the greatest number of phenols. The lowest number of the phenols studies was found in the Tatry populations. Each population showed its own particular spectrum of phenolic compounds. It was found that the populations originating from similar habitats showed more common spots than those from different regions. Populations from the Tatra region were found to differ most from the rest.

Evaluation of antioxidant properties, elemental and phenolic contents composition of wild nettle (Urtica dioica L.) from Tunceli in Turkey.

Science.gov (United States)

Yildirim, N C; Turkoglu, S; Ince, O K; Ince, M

2013-11-03

Wild nettle (Urtica dioica L.) types were sampled from different geographical regions in Tunceli (Turkey) to determine their mineral, vitamin, phenolic contents and their antioxidant properties. The total phenol varied from 37.419 ± 0.380 to 19.182 ± 1.00 mg of GAEs g(-1) of dry nettle. The highest radical scavenging effect was observed in Mazgirt parting of the ways 7.5 km with 33.70 ± 0.849 mg mL(-1). The highest reducing power was observed in the nettles from Mazgirt parting of the ways 7.5 km. Among the various macronutrients estimated in the plant samples, potassium was present in the highest quantity followed by calcium and phosphate. Kaempferol and resveratrol were not determined in some nettle samples but rutin levels were determined in all samples. Vitamin A concentrations were ranged between 13.64 ± 1.90 and 5.74 ± 1.00 (mg kg(-1) dry weight). These results show that Urtica dioica L. collected from Tunceli in Turkey could be considered as a natural alternative source for food, pharmacology and medicine sectors.

High-performance liquid chromatography-fluorescence assay of pyruvic acid to determine cysteine conjugate beta-lyase activity : application to S-1,2-dichlorovinyl-L-cysteine and S-2-benzothiazolyl-L-cysteine

NARCIS (Netherlands)

Stijntjes, G.J.; te Koppele, J.M.; Vermeulen, N P

1992-01-01

An HPLC-fluorescence assay has been developed for the determination of the activity of rat renal cytosolic cysteine conjugate beta-lyase. The method is based on isocratic HPLC separation and fluorescence detection of pyruvic acid, derivatized with o-phenylenediamine (OPD), and is shown to be rapid,

Changes of phenolic profiles and antioxidant activity in canaryseed (Phalaris canariensis L.) during germination.

Science.gov (United States)

Chen, Zhijie; Yu, Lilei; Wang, Xinkun; Gu, Zhenxin; Beta, Trust

2016-03-01

Canaryseed is an important cereal crop in western Canada. The changes of the total phenolic content (TPC), antioxidant activities, phenolic acid profiles (free and bound) of canaryseed during germination were investigated in the present study. The growth properties also were investigated. Fresh weight, shoot length and root length increased, whereas dry mass of canaryseed decreased during germination. A 22.3% loss of dry matter was observed at 120h of germination. The total phenolic content and antioxidant activities of free and bound extracts showed a general trend of germinated seeds>raw seeds>soaked seeds. Free, bound and total phenolic content significantly increased 1042%, 120% and 741% at the end of germination as compared to raw seeds (pphenolic content and antioxidant activities. TPC and ORAC values showed the highest correlation (r=0.9984). Six phenolic acids in free phenolic extracts and seven phenolic acids in bound phenolic extracts were detected, respectively. Bound ferulic acid, the dominant phenolic acid in canaryseed, significantly increased during germination (p<0.05). Study showed that germination provided a new approach to further develop canaryseed as a functional food for human consumption. Copyright © 2015 Elsevier Ltd. All rights reserved.

Molecular cloning, purification, and characterization of a novel polyMG-specific alginate lyase responsible for alginate MG block degradation in Stenotrophomas maltophilia KJ-2

Energy Technology Data Exchange (ETDEWEB)

Lee, Su In; Kim, Hee Sook [Kyungsung Univ., Busan (Korea, Republic of). Dept. of Food Science and Biotechnology; Choi, Sung Hee; Lee, Eun Yeol [Kyung Hee Univ., Gyeonggi-do (Korea, Republic of). Dept. of Chemical Engineering

2012-09-15

A gene for a polyMG-specific alginate lyase possessing a novel structure was identified and cloned from Stenotrophomas maltophilia KJ-2 by using PCR with homologous nucleotide sequences-based primers. The recombinant alginate lyase consisting of 475 amino acids was purified on Ni-Sepharose column and exhibited the highest activity at pH 8 and 40 C. Interestingly, the recombinant alginate lyase was expected to have a similar catalytic active site of chondroitin B lyase but did not show chondroitin lyase activity. In the test of substrate specificity, the recombinant alginate lyase preferentially degraded the glycosidic bond of polyMG-block than polyM-block and polyG-block. The chemical structures of the degraded alginate oligosaccharides were elucidated to have mannuronate (M) at the reducing end on the basis of NMR analysis, supporting that KJ-2 polyMG-specific alginate lyase preferably degraded the glycosidic bond in M-G linkage than that in G-M linkage. The KJ-2 polyMG-specific alginate lyase can be used in combination with other alginate lyases for a synergistic saccharification of alginate. (orig.)

Agrimonia eupatoria L. and Cynara cardunculus L. Water Infusions: Phenolic Profile and Comparison of Antioxidant Activities

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Anika Kuczmannová

2015-11-01

Full Text Available Reactive oxygen species (ROS are highly considered in the ethiopathogenesis of different pathological conditions because they may cause significant damage to cells and tissues. In this paper, we focused on potential antioxidant properties of two medical plants such as the Agrimonia eupatoria L. and Cynara cardunculus L. Both plants have previously been studied for their pharmacological activities, especially as hepatoprotective and hypoglycemic activities. It has been suggested, that their effects are related to the antioxidant properties of polyphenols, which are dominant compounds of the plants’ extracts. In the present study HPLC-MS analysis of water infusion was performed allowing the identification of several phenolic constituents. Furthermore, antioxidant effects of the two extracts were compared showing higher effects for agrimony extract compared to artichoke. Thus, agrimony was selected for the in vivo study using the skin flap viability model. In conclusion, our results provide evidence that the A. eupatoria extract may be a valuable source of polyphenols to be studied for the future development of supplements useful in the prevention of diseases linked to oxidative stress.

Box-Behnken factorial design to obtain a phenolic-rich extract from the aerial parts of Chelidonium majus L.

Science.gov (United States)

Grosso, Clara; Ferreres, Federico; Gil-Izquierdo, Angel; Valentão, Patrícia; Sampaio, Maria; Lima, Júlio; Andrade, Paula B

2014-12-01

A Box-Behnken design (BBD) was developed to study the influence of four parameters (X1: % methanol; X2: extraction time; X3: extraction temperature; X4: solid/solvent ratio) on two responses, namely extraction yield and phenolics content of the aerial parts of Chelidonium majus L. The model presented a good fit to the experimental results for the extraction yield, being significantly influenced by X1 and X4. On the other hand a parameter reduction was necessary to run the model for phenolics content, showing that only X1 and X2 had great influence on the response. Two best extraction conditions were defined: X1=76.8% MeOH, X2=150.0 min, X3=60.0°C and X4=1:100 and X1=69.2%, X2=150 min, X3=42.5°C and X4=1:100. Moreover, the HPLC-DAD-ESI/MS(n) analysis conducted with the center point sample revealed the presence of 15 alkaloids and 15 phenolic compounds, from which the 9 flavonoids and 3 hydroxycinnamic acids are described for the first time. Only phenolic compounds were quantified by a validated HPLC-DAD method, the pair quercetin-3-O-rutinoside+quercetin-3-O-glucoside dominating all the 29 extracts. This study is of great importance for future works that seek to apply the phenolic profile to the quality control of C. majus samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Brain catecholamine depletion and motor impairment in a Th knock-in mouse with type B tyrosine hydroxylase deficiency.

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Korner, Germaine; Noain, Daniela; Ying, Ming; Hole, Magnus; Flydal, Marte I; Scherer, Tanja; Allegri, Gabriella; Rassi, Anahita; Fingerhut, Ralph; Becu-Villalobos, Damasia; Pillai, Samyuktha; Wueest, Stephan; Konrad, Daniel; Lauber-Biason, Anna; Baumann, Christian R; Bindoff, Laurence A; Martinez, Aurora; Thöny, Beat

2015-10-01

Tyrosine hydroxylase catalyses the hydroxylation of L-tyrosine to l-DOPA, the rate-limiting step in the synthesis of catecholamines. Mutations in the TH gene encoding tyrosine hydroxylase are associated with the autosomal recessive disorder tyrosine hydroxylase deficiency, which manifests phenotypes varying from infantile parkinsonism and DOPA-responsive dystonia, also termed type A, to complex encephalopathy with perinatal onset, termed type B. We generated homozygous Th knock-in mice with the mutation Th-p.R203H, equivalent to the most recurrent human mutation associated with type B tyrosine hydroxylase deficiency (TH-p.R233H), often unresponsive to l-DOPA treatment. The Th knock-in mice showed normal survival and food intake, but hypotension, hypokinesia, reduced motor coordination, wide-based gate and catalepsy. This phenotype was associated with a gradual loss of central catecholamines and the serious manifestations of motor impairment presented diurnal fluctuation but did not improve with standard l-DOPA treatment. The mutant tyrosine hydroxylase enzyme was unstable and exhibited deficient stabilization by catecholamines, leading to decline of brain tyrosine hydroxylase-immunoreactivity in the Th knock-in mice. In fact the substantia nigra presented an almost normal level of mutant tyrosine hydroxylase protein but distinct absence of the enzyme was observed in the striatum, indicating a mutation-associated mislocalization of tyrosine hydroxylase in the nigrostriatal pathway. This hypomorphic mouse model thus provides understanding on pathomechanisms in type B tyrosine hydroxylase deficiency and a platform for the evaluation of novel therapeutics for movement disorders with loss of dopaminergic input to the striatum. © The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Phytochemical Profiling of Flavonoids, Phenolic Acids, Terpenoids, and Volatile Fraction of a Rosemary (Rosmarinus officinalis L.) Extract.

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Mena, Pedro; Cirlini, Martina; Tassotti, Michele; Herrlinger, Kelli A; Dall'Asta, Chiara; Del Rio, Daniele

2016-11-19

This paper presents a comprehensive analysis of the phytochemical profile of a proprietary rosemary ( Rosmarinus officinalis L.) extract rich in carnosic acid. A characterization of the (poly)phenolic and volatile fractions of the extract was carried out using mass spectrometric techniques. The (poly)phenolic composition was assessed by ultra-high performance liquid chromatography-electrospray ionization-mass spectrometry (UHPLC-ESI-MS n ) and a total of 57 compounds were tentatively identified and quantified, 14 of these being detected in rosemary extract for the first time. The rosemary extract contained 24 flavonoids (mainly flavones, although flavonols and flavanones were also detected), 5 phenolic acids, 24 diterpenoids (carnosic acid, carnosol, and rosmanol derivatives), 1 triterpenoid (betulinic acid), and 3 lignans (medioresinol derivatives). Carnosic acid was the predominant phenolic compound. The volatile profile of the rosemary extract was evaluated by head space solid-phase microextraction (HS-SPME) linked to gas chromatography-mass spectrometry (GC-MS). Sixty-three volatile molecules (mainly terpenes, alcohols, esters, aldehydes, and ketones) were identified. This characterization extends the current knowledge on the phytochemistry of Rosmarinus officinalis and is, to our knowledge, the broadest profiling of its secondary metabolites to date. It can assist in the authentication of rosemary extracts or rosemary-containing products or in testing its bioactivity. Moreover, this methodological approach could be applied to the study of other plant-based food ingredients.

Antioxidant capacity, polyphenolic content and tandem HPLC-DAD-ESI/MS profiling of phenolic compounds from the South American berries Luma apiculata and L. chequén.

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Simirgiotis, Mario J; Bórquez, Jorge; Schmeda-Hirschmann, Guillermo

2013-08-15

Native Myrtaceae fruits were gathered by South American Amerindians as a food source. At present, there is still some regional consume of the small berries from trees belonging to genus Luma that occurs in southern Chile and Argentina. The aerial parts and berries from Luma apiculata and Luma chequen were investigated for phenolic constituents and antioxidant capacity. A high performance electrospray ionisation mass spectrometry method was developed for the rapid identification of phenolics in polar extracts from both species. Thirty-one phenolic compounds were detected and 27 were identified or tentatively characterised based on photodiode array UV-vis spectra (DAD), ESI-MS-MS spectrometric data and spiking experiments with authentic standards. Twelve phenolic compounds were detected in L. apiculata fruits and 12 in the aerial parts while L. chequen yielded 10 compounds in fruits and 16 in aerial parts, respectively. From the compounds occurring in both Luma species, seven were identified as tannins or their monomers, 15 were flavonol derivatives and five were anthocyanins. The whole berry and aerial parts extracts presented high antioxidant capacity in the DPPH assay (IC50 of 10.41±0.02 and 2.44±0.03 μg/mL for L. apiculata, 12.89±0.05 and 3.22±0.05 for L. chequen, respectively), which can be related to the diverse range of phenolics detected. The antioxidant capacity together with the high polyphenolic contents and compounds identified can support at least in part, their use as botanical drugs. From the compounds identified in both species, 3-O-(6″-O-galloyl)-hexose derivatives of myricetin, quercetin, laricitrin and isorhamnetin are reported for the first time for the genus Luma. Copyright © 2013 Elsevier Ltd. All rights reserved.

Sequence analysis and overexpression of a pectin lyase gene (pel1) from Aspergillus oryzae KBN616.

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Kitamoto, N; Yoshino-Yasuda, S; Ohmiya, K; Tsukagoshi, N

2001-01-01

A gene (pel1) encoding pectin lyase (Pel1) was isolated from a shoyu koji mold, Aspergillus oryzae KBN616, and characterized. The structural gene comprised 1,196 bp with a single intron. The ORF encoded 381 amino acids with a signal peptide of 20 amino acids. The deduced amino acid sequence showed high similarity to those of Aspergillus niger pectin lyases and Glomerella cingulata PnlA. The pel1 gene was successfully overexpressed under the promoter of the A. oryzae TEF1 gene. The molecular mass of the recombinant pectin lyase substantially coincided with that calculated based on nucleotide sequence.

Autophosphorylation of JAK2 on tyrosines 221 and 570 regulates its activity.

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Argetsinger, Lawrence S; Kouadio, Jean-Louis K; Steen, Hanno; Stensballe, Allan; Jensen, Ole N; Carter-Su, Christin

2004-06-01

The tyrosine kinase JAK2 is a key signaling protein for at least 20 receptors in the cytokine/hematopoietin receptor superfamily and is a component of signaling by insulin receptor and several G-protein-coupled receptors. However, there is only limited knowledge of the physical structure of JAK2 or which of the 49 tyrosines in JAK2 are autophosphorylated. In this study, mass spectrometry and two-dimensional peptide mapping were used to determine that tyrosines 221, 570, and 1007 in JAK2 are autophosphorylated. Phosphorylation of tyrosine 570 is particularly robust. In response to growth hormone, JAK2 was rapidly and transiently phosphorylated at tyrosines 221 and 570, returning to basal levels by 60 min. Analysis of the sequences surrounding tyrosines 221 and 570 in JAK2 and tyrosines in other proteins that are phosphorylated in response to ligands that activate JAK2 suggests that the YXX[L/I/V] motif is one of the motifs recognized by JAK2. Experiments using JAK2 with tyrosines 221 and 570 mutated to phenylalanine suggest that tyrosines 221 and 570 in JAK2 may serve as regulatory sites in JAK2, with phosphorylation of tyrosine 221 increasing kinase activity and phosphorylation of tyrosine 570 decreasing kinase activity and thereby contributing to rapid termination of ligand activation of JAK2.

Characterization of phenolic compounds and antinociceptive activity of Sempervivum tectorum L. leaf juice.

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Alberti, Ágnes; Béni, Szabolcs; Lackó, Erzsébet; Riba, Pál; Al-Khrasani, Mahmoud; Kéry, Ágnes

2012-11-01

Sempervivum tectorum L. (houseleek) leaf juice has been known as a traditional herbal remedy. The aim of the present study was the chemical characterization of its phenolic compounds and to develop quantitation methods for its main flavonol glycoside, as well as to evaluate its antinociceptive activity. Lyophilized houseleek leaf juice was studied by HPLC-DAD coupled to electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) to identify flavonol glycosides, hydroxy-benzoic and hydroxy-cinnamic acids. Ten flavonol glycosides and sixteen phenolic acid compounds were identified or tentatively characterized. Structure of the main flavonol compound was identified by nuclear magnetic resonance spectroscopy. Three characteristic kaempferol glycosides were isolated and determined by LC-ESI-MS/MS with external calibration method, using the isolated compounds as standard. The main flavonol glycoside was also determined by HPLC-DAD. Validated HPLC-DAD and LC-ESI-MS/MS methods were developed to quantify kaempferol-3-O-rhamnosyl-glucoside-7-O-rhamnoside and two other kaempferol glycosides. Antinociceptive activity of houseleek leaf juice was investigated by writhing test of mice. Sempervivum extract significantly reduced pain in the mouse writhing test. Copyright © 2012 Elsevier B.V. All rights reserved.

Structure-based functional annotation of putative conserved proteins having lyase activity from Haemophilus influenzae.

Science.gov (United States)

Shahbaaz, Mohd; Ahmad, Faizan; Imtaiyaz Hassan, Md

2015-06-01

Haemophilus influenzae is a small pleomorphic Gram-negative bacteria which causes several chronic diseases, including bacteremia, meningitis, cellulitis, epiglottitis, septic arthritis, pneumonia, and empyema. Here we extensively analyzed the sequenced genome of H. influenzae strain Rd KW20 using protein family databases, protein structure prediction, pathways and genome context methods to assign a precise function to proteins whose functions are unknown. These proteins are termed as hypothetical proteins (HPs), for which no experimental information is available. Function prediction of these proteins would surely be supportive to precisely understand the biochemical pathways and mechanism of pathogenesis of Haemophilus influenzae. During the extensive analysis of H. influenzae genome, we found the presence of eight HPs showing lyase activity. Subsequently, we modeled and analyzed three-dimensional structure of all these HPs to determine their functions more precisely. We found these HPs possess cystathionine-β-synthase, cyclase, carboxymuconolactone decarboxylase, pseudouridine synthase A and C, D-tagatose-1,6-bisphosphate aldolase and aminodeoxychorismate lyase-like features, indicating their corresponding functions in the H. influenzae. Lyases are actively involved in the regulation of biosynthesis of various hormones, metabolic pathways, signal transduction, and DNA repair. Lyases are also considered as a key player for various biological processes. These enzymes are critically essential for the survival and pathogenesis of H. influenzae and, therefore, these enzymes may be considered as a potential target for structure-based rational drug design. Our structure-function relationship analysis will be useful to search and design potential lead molecules based on the structure of these lyases, for drug design and discovery.

Phenolic Content, and Antioxidant and Antimicrobial Activities of ...

African Journals Online (AJOL)

Erah

Methods: The content of total phenols, flavonoids and anthocyanins of the alcohol, hydroalcohol and aqueous extracts of ... Keywords: Crataegus oxyacantha L.; Natural phenolic compounds; Antioxidant and antimicrobial activity, Southeast Serbia. ..... Antioxidant activities of Sechium edule (Jacq.) Swart extracts, Food ...

Determination of the Phenolic Profile and Antioxidant Properties of Salvia viridis L. Shoots: A Comparison of Aqueous and Hydroethanolic Extracts

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Izabela Grzegorczyk-Karolak

2018-06-01

Full Text Available Salvia viridis L. is an annual herb used in Mediterranean medicine. The purpose of this study was to determine the polyphenol profile of aqueous (decoction and infusion and hydroethanolic extracts of aerial parts of field-grown S.viridis and to evaluate their antioxidant activity. The polyphenol profiling was performed via UPLC-DAD/ESI-MS. Additionally, the total polyphenol content in extracts tested were determined by UV-Vis spectrophotometry using the Folin-Ciocalteu assay. The antioxidant effect was evaluated by the FRAP, DPPH, ABTS, O2•− scavenging and TBARS methods. The hydroethanolic extract gave the highest content of total phenolic compounds, followed by the infusion. The UPLC-DAD/ESI-MS analysis of extracts showed a total of 19 phenolic compounds identified as flavonoids (four compounds, phenylethanoids (eight compounds and phenolic acids (seven compounds. Rosmarinic acid was the predominant phenolic acid, verbascoside was the predominant phenylethanoid, while apigenin glucuronide or methylluteolin glucuronide, depending on the sample, were the predominant flavonoids in the analyzed extracts. The presence of a high polyphenol level indicated a high antioxidant activity of both the infusion and the hydroalcoholic extract. These results indicate that S. viridis is a rich resource of phenolic compounds and can be used in dietary applications with the potential to reduce oxidative stress.

Biodegradation of high strength phenolic wastewater in a modified external loop inversed fluidized bed airlift bioreactor (EIFBAB)

Energy Technology Data Exchange (ETDEWEB)

Aye, T. T.; Loh, K-C. [National University of Singapore, Dept. of Chemical and Environmental Engineering, (Singapore)

2003-12-01

Phenol degradation at high concentrations was investigated in both batch and continuous mode, using a modified external loop inversed fluidized bed airlift bioreactor (EIFBAB). It was found that the modified EIFBAB, when operated at five litres/hour was capable of degrading 3,000 mg/L phenol. Under continuous operation the bioreactor was capable of degrading up to 5,000 mg/L phenol, with gradual acclimatization of the biofilm on the expanded polystyrene beads. Response of the system under shock loading was also evaluated. Results showed that the system was able to absorb the shock well up to 5,000 mg/L phenol. Although phenol breakthrough was evident in the effluent beyond 4,500 mg/L., the increase in effluent phenol concentration was gradual, and the effluent concentration did not increase beyond 1,000 mg/L phenol. 6 refs., 3 tabs., 3 figs.

Cloning and study of the pectate lyase gene of Erwinia carotovora

International Nuclear Information System (INIS)

Bukanov, N.O.; Fonshtein, M.Yu.; Evtushenkov, A.N.; Syarinskii, M.A.; Strel'chenko, P.P.; Yankovski, N.K.; Alikhanyan, S.I.; Fomichev, Yu.K.; Debabov, V.G.

1986-01-01

The cloning of the gene of a secretable protein of Erwinia carotovora, pectate lyase, in Escherichia coli was described. Primary cloning was conducted using the phage vector λ 47.1. In the gene library of E. carotovora obtained, eight phages carrying the gene sought were identified according to the appearance of enzymatic activity of the gene product, pectate lyase, in situ. The BamHI fragment of DNA, common to all these phages, was recloned on the plasmid pUC19. It was shown that the cloned pectate lyase gene is represented on the E. carotovora chromosome in one copy. Methods of production of representative gene libraries on phage vectors from no less than 1 μg of cloned DNA even for the genomes of eukaryotes have now been developed. Vectors have been created, for example, λ 47.1, permitting the selection only of hybrid molecules. A number of methods have been developed for the search for a required gene in the library, depending on whether the cloned gene can be expressed or not, and if it can, what properties it will impart to the hybrid clone containing it

pH dependent antioxidant activity of lettuce (L. sativa) and synergism with added phenolic antioxidants.

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Altunkaya, Arzu; Gökmen, Vural; Skibsted, Leif H

2016-01-01

Influence of pH on the antioxidant activities of combinations of lettuce extract (LE) with quercetin (QC), green tea extract (GTE) or grape seed extract (GSE) was investigated for both reduction of Fremy's salt in aqueous solution using direct electron spin resonance (ESR) spectroscopy and in L-α-phosphatidylcholine liposome peroxidation assay measured following formation of conjugated dienes. All examined phenolic antioxidants showed increasing radical scavenging effect with increasing pH values by using both methods. QC, GTE and GSE acted synergistically in combination with LE against oxidation of peroxidating liposomes and with QC showing the largest effect. The pH dependent increase of the antioxidant activity of the phenols is due to an increase of their electron-donating ability upon deprotonation and to their stabilization in alkaline solutions leading to polymerization reaction. Such polymerization reactions of polyphenolic antioxidants can form new oxidizable -OH moieties in their polymeric products resulting in a higher radical scavenging activity. Copyright © 2015 Elsevier Ltd. All rights reserved.

Physiochemical and Phytochemical Properties of Wax Apple (Syzygium samarangense [Blume] Merrill & L. M. Perry var. Jambu Madu as Affected by Growth Regulator Application

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Mohammad Moneruzzaman Khandaker

2012-01-01

Full Text Available This study represents the first paper of the effects of growth regulators on the physiochemical and phytochemical properties of the wax apple fruit, a widely cultivated fruit tree in southeast Asia. Net photosynthesis, sucrose phosphate synthase (SPS activity, peel color, fruit firmness, juice content, pH value, total soluble solids (TSSs, and the sugar acid ratio were all significantly increased in growth regulators (PGRs treated fruits. The application of gibberellin (GA3, naphthalene acetic acid (NAA, and 2,4-dichlorophenoxy acetic acid (2,4-D significantly reduced titratable acidity and increased total sugar and carbohydrate content compared to the control. The 50 mg/L GA3, 10 mg/L NAA, and 5 mg/L 2,4-D treatments produced the greatest increases in phenol and flavonoid content; vitamin C content was also higher for these treatments. PGR treatment significantly affected chlorophyll, anthocyanin, and carotene content and produced higher phenylalanine ammonia lyase (PAL and antioxidant activity levels. There was a positive correlation between peel color and TSS and antioxidant activity and both phenol and flavonoid content and PAL activity and anthocyanin formation. A taste panel assessment was also performed, and the highest scores were given to fruits that had been treated with GA3 or auxin. The study showed that application of 50 mg/L GA3, 10 mg/L NAA, and 5 mg/L 2,4-D once a week from bud development to fruit maturation increased the physiochemical and phytochemical properties of wax apple fruits.

Sulfur mobilization in cyanobacteria: the catalytic mechanism of L-cystine C-S lyase (C-DES) from synechocystis.

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Campanini, Barbara; Schiaretti, Francesca; Abbruzzetti, Stefania; Kessler, Dorothea; Mozzarelli, Andrea

2006-12-15

Sulfur mobilization represents one of the key steps in ubiquitous Fe-S clusters assembly and is performed by a recently characterized set of proteins encompassing cysteine desulfurases, assembly factors, and shuttle proteins. Despite the evolutionary conservation of these proteins, some degree of variability among organisms was observed, which might reflect functional specialization. L-Cyst(e)ine lyase (C-DES), a pyridoxal 5'-phosphatedependent enzyme identified in the cyanobacterium Synechocystis, was reported to use preferentially cystine over cysteine with production of cysteine persulfide, pyruvate, and ammonia. In this study, we demonstrate that C-DES sequences are present in all cyanobacterial genomes and constitute a new family of sulfur-mobilizing enzymes, distinct from cysteine desulfurases. The functional properties of C-DES from Synechocystis sp. PCC 6714 were investigated under pre-steady-state and steady-state conditions. Single wavelength and rapid scanning stopped-flow kinetic data indicate that the internal aldimine reacts with cystine forming an external aldimine that rapidly decays to a transient quinonoid species and stable tautomers of the alpha-aminoacrylate Schiff base. In the presence of cysteine, the transient formation of a dipolar species precedes the selective and stable accumulation of the enolimine tautomer of the external aldimine, with no formation of the alpha-aminoacrylate Schiff base under reducing conditions. Effective sulfur mobilization from cystine might represent a mechanism that allows adaptation of cyanobacteria to different environmental conditions and to light-dark cycles.

Evaluating the value proposition for improving vaccine thermostability to increase vaccine impact in low and middle-income countries.

Science.gov (United States)

Karp, Christopher L; Lans, Deborah; Esparza, José; Edson, Eleanore B; Owen, Katey E; Wilson, Christopher B; Heaton, Penny M; Levine, Orin S; Rao, Raja

2015-07-09

The need to keep vaccines cold in the face of high ambient temperatures and unreliable access to electricity is a challenge that limits vaccine coverage in low and middle-income countries (LMICs). Greater vaccine thermostability is generally touted as the obvious solution. Despite conventional wisdom, comprehensive analysis of the value proposition for increasing vaccine thermostability has been lacking. Further, while significant investments have been made in increasing vaccine thermostability in recent years, no vaccine products have been commercialized as a result. We analyzed the value proposition for increasing vaccine thermostability, grounding the analysis in specific vaccine use cases (e.g., use in routine immunization [RI] programs, or in campaigns) and in the broader context of cold chain technology and country level supply chain system design. The results were often surprising. For example, cold chain costs actually represent a relatively small fraction of total vaccine delivery system costs. Further, there are critical, vaccine use case-specific temporal thresholds that need to be overcome for significant benefits to be reaped from increasing vaccine thermostability. We present a number of recommendations deriving from this analysis that suggest a rational path toward unlocking the value (maximizing coverage, minimizing total system costs) of increased vaccine thermostability, including: (1) the full range of thermostability of existing vaccines should be defined and included in their labels; (2) for new vaccines, thermostability goals should be addressed up-front at the level of the target product profile; (3) improving cold chain infrastructure and supply chain system design is likely to have the largest impact on total system costs and coverage in the short term-and will influence the degree of thermostability required in the future; (4) in the long term, there remains value in monitoring the emergence of disruptive technologies that could remove the

Structure Based Thermostability Prediction Models for Protein Single Point Mutations with Machine Learning Tools.

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Lei Jia

Full Text Available Thermostability issue of protein point mutations is a common occurrence in protein engineering. An application which predicts the thermostability of mutants can be helpful for guiding decision making process in protein design via mutagenesis. An in silico point mutation scanning method is frequently used to find "hot spots" in proteins for focused mutagenesis. ProTherm (http://gibk26.bio.kyutech.ac.jp/jouhou/Protherm/protherm.html is a public database that consists of thousands of protein mutants' experimentally measured thermostability. Two data sets based on two differently measured thermostability properties of protein single point mutations, namely the unfolding free energy change (ddG and melting temperature change (dTm were obtained from this database. Folding free energy change calculation from Rosetta, structural information of the point mutations as well as amino acid physical properties were obtained for building thermostability prediction models with informatics modeling tools. Five supervised machine learning methods (support vector machine, random forests, artificial neural network, naïve Bayes classifier, K nearest neighbor and partial least squares regression are used for building the prediction models. Binary and ternary classifications as well as regression models were built and evaluated. Data set redundancy and balancing, the reverse mutations technique, feature selection, and comparison to other published methods were discussed. Rosetta calculated folding free energy change ranked as the most influential features in all prediction models. Other descriptors also made significant contributions to increasing the accuracy of the prediction models.

Role of hydroperoxide lyase in white-backed planthopper (Sogatella furcifera Horváth)-induced resistance to bacterial blight in rice, Oryza sativa L.

Science.gov (United States)

Gomi, Kenji; Satoh, Masaru; Ozawa, Rika; Shinonaga, Yumi; Sanada, Sachiyo; Sasaki, Katsutomo; Matsumura, Masaya; Ohashi, Yuko; Kanno, Hiroo; Akimitsu, Kazuya; Takabayashi, Junji

2010-01-01

A pre-infestation of the white-backed planthopper (WBPH), Sogatella furcifera Horváth, conferred resistance to bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo) in rice (Oryza sativa L.) under both laboratory and field conditions. The infestation of another planthopper species, the brown planthopper (BPH) Nilaparvata lugens Stål, did not significantly reduce the incidence of bacterial blight symptoms. A large-scale screening using a rice DNA microarray and quantitative RT-PCR revealed that WBPH infestation caused the upregulation of more defence-related genes than did BPH infestation. Hydroperoxide lyase 2 (OsHPL2), an enzyme for producing C(6) volatiles, was upregulated by WBPH infestation, but not by BPH infestation. One C(6) volatile, (E)-2-hexenal, accumulated in rice after WBPH infestation, but not after BPH infestation. A direct application of (E)-2-hexenal to a liquid culture of Xoo inhibited the growth of the bacterium. Furthermore, a vapour treatment of rice plants with (E)-2-hexenal induced resistance to bacterial blight. OsHPL2-overexpressing transgenic rice plants exhibited increased resistance to bacterial blight. Based on these data, we conclude that OsHPL2 and its derived (E)-2-hexenal play some role in WBPH-induced resistance in rice.

Biochemical markers assisted screening of Fusarium wilt resistant Musa paradisiaca (L.) cv. puttabale micropropagated clones.

Science.gov (United States)

Venkatesh; Krishna, V; Kumar, K Girish; Pradeepa, K; Kumar, S R Santosh; Kumar, R Shashi

2013-07-01

An efficient protocol was standardized for screening of panama wilt resistant Musa paradisiaca cv. Puttabale clones, an endemic cultivar of Karnataka, India. The synergistic effect of 6-benzyleaminopurine (2 to 6 mg/L) and thidiazuron (0.1 to 0.5 mg/L) on MS medium provoked multiple shoot induction from the excised meristem. An average of 30.10 +/- 5.95 shoots was produced per propagule at 4 mg/L 6-benzyleaminopurine and 0.3 mg/L thidiazuron concentrations. Elongation of shoots observed on 5 mg/L BAP augmented medium with a mean length of 8.38 +/- 0.30 shoots per propagule. For screening of disease resistant clones, multiple shoot buds were mutated with 0.4% ethyl-methane-sulfonate and cultured on MS medium supplemented with Fusarium oxysporum f. sp. cubense (FOC) culture filtrate (5-15%). Two month old co-cultivated secondary hardened plants were used for screening of disease resistance against FOC by the determination of biochemical markers such as total phenol, phenylalanine ammonia lyase, oxidative enzymes like peroxidase, polyphenol oxidase, catalase and PR-proteins like chitinase, beta-1-3 glucanase activities. The mutated clones of M. paradisiaca cv. Puttabale cultured on FOC culture filtrate showed significant increase in the levels of biochemical markers as an indicative of acquiring disease resistant characteristics to FOC wilt.

Effects of nitrogen fertilization on the phenolic composition and antioxidant properties of basil (Ocimum basilicum L.).

Science.gov (United States)

Nguyen, Phuong M; Niemeyer, Emily D

2008-09-24

Many herbs and spices have been shown to contain high levels of polyphenolic compounds with potent antioxidant properties. In the present study, we explore how nutrient availability, specifically nitrogen fertilization, affects the production of polyphenolic compounds in three cultivars (Dark Opal, Genovese, and Sweet Thai) of the culinary herb, basil ( Ocimum basilicum L.). Nitrogen fertilization was found to have a significant effect on total phenolic levels in Dark Opal ( p basil with statistically higher phenolic contents observed when nutrient availability was limited at the lowest (0.1 mM) applied nitrogen treatment. Similarly, basil treated at the lowest nitrogen fertilization level generally contained significantly higher rosmarinic ( p = 0.001) and caffeic ( p = 0.001) acid concentrations than basil treated at other nitrogen levels. Nitrogen fertilization also affected antioxidant activity ( p = 0.002) with basil treated at the highest applied nitrogen level, 5.0 mM, exhibiting lower antioxidant activity than all other nitrogen treatments. The anthocyanin content of Dark Opal basil was not affected by applied nitrogen level, but anthocyanin concentrations were significantly impacted by growing season ( p = 0.001). Basil cultivar was also determined to have a statistically significant effect on total phenolic levels, rosmarinic and caffeic acid concentrations, and antioxidant activities.

The metabolism of L-phenylalanine and L-tyrosine by liver cells isolated from adrenalectomized rats and from streptozotocin-diabetic rats.

OpenAIRE

Stanley, J C; Fisher, M J; Pogson, C I

1985-01-01

Flux through, and maximal activities of, key enzymes of phenylalanine and tyrosine degradation were measured in liver cells prepared from adrenalectomized rats and from streptozotocin-diabetic rats. Adrenalectomy decreased the phenylalanine hydroxylase flux/activity ratio; this was restored by steroid treatment in vivo. Changes in the phosphorylation state of the hydroxylase may mediate these effects; there was no significant change in the maximal activity of the hydroxylase. Tyrosine metabol...

Effects of 20 standard amino acids on the growth, total fatty acids production, and γ-linolenic acid yield in Mucor circinelloides.

Science.gov (United States)

Tang, Xin; Zhang, Huaiyuan; Chen, Haiqin; Chen, Yong Q; Chen, Wei; Song, Yuanda

2014-12-01

Twenty standard amino acids were examined as single nitrogen source on the growth, total fatty acids production, and yield of γ-linolenic acid (GLA) in Mucor circinelloides. Of the amino acids, tyrosine gave the highest biomass and lipid accumulation and thus resulted in a high GLA yield with respective values of 17.8 g/L, 23 % (w/w, dry cell weight, DCW), and 0.81 g/L, which were 36, 25, and 72 % higher than when the fungus was grown with ammonium tartrate. To find out the potential mechanism underlying the increased lipid accumulation of M. circinelloides when grown on tyrosine, the activity of lipogenic enzymes of the fungus during lipid accumulation phase was measured. The enzyme activities of glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and ATP-citrate lyase were up-regulated, while NADP-isocitrate dehydrogenase was down-regulated by tyrosine during the lipid accumulation phase of the fungus which suggested that these enzymes may be involved in the increased lipid biosynthesis by tyrosine in this fungus.

Evaluation of phenolic profile, enzyme inhibitory and antimicrobial activities of Nigella sativa L. seed extracts

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Anela Topcagic

2017-11-01

Full Text Available Black cumin (Nigella sativa L. [N.sativa] seed extracts demonstrated numerous beneficial biological effects including, among others, antidiabetic, anticancer, immunomodulatory, antimicrobial, anti-inflammatory, antihypertensive, and antioxidant activity. To better understand the phytochemical composition of N. sativa seeds, methanol seed extracts were analyzed for phenolic acid and flavonoid content. Furthermore, we tested N. sativa methanol, n-hexane, and aqueous seed extracts for their inhibitory activity against butyrylcholinesterase (BChE and catalase (CAT as well as for antimicrobial activity against several bacterial and a yeast strains. The phenolic content of N. sativa was analyzed using ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS. The inhibition of BChE was assessed by modified Ellman’s method, and the inhibition of CAT was determined by monitoring hydrogen peroxide consumption. The extracts were tested against Bacillus subtilis, Staphylococcus aureus, Salmonella enterica, and Escherichia coli using the agar diffusion method. The UHPLC-MS/MS method allowed the identification and quantification of 23 phenolic compounds within 15 minutes. The major components found in N. sativa seed extract were sinapinic acid (7.22 ± 0.73 µg/mg as a phenolic acid and kaempferol (11.74 ± 0.92 µg/mg as a flavonoid. All extracts showed inhibitory activity against BChE, with methanol seed extract demonstrating the highest inhibitory activity (inhibitory concentration 50% [IC50] 79.11 ± 6.06 µg/ml. The methanol seed extract also showed strong inhibitory activity against CAT with an IC50 value of 6.61 ± 0.27 µg/ml. Finally, the methanol extract exhibited considerable inhibitory activity against the tested microbial strains. Overall, this is the first study to investigate the ability of black cumin seed extracts to inhibit CAT. Our results indicate that N. sativa seed can be considered as an effective inhibitor

Development of thermostable Peste des Petits Ruminants (PPR) virus vaccine and assessment of molecular changes in the F gene

International Nuclear Information System (INIS)

Palaniswami, K.S.; Thangavelu, A.; Velmurugan, R.

2005-01-01

Two Indian PPRV isolates were subjected to thermal hardening procedures to increase the proportion of temperature-resistant virions. Initial infectivity loss was compensated by titre increases on subsequent cell passages at 37 deg C. The immunogenicity of 'thermostable' viruses was assessed by virulent PPRV challenge and for safety by host animal inoculation and antibodies assessment. Vaccine viruses were not found using PCR on ocular and nasal swabs, although virus nucleic acid and antigens were demonstrated in spleen and lymph nodes by FAT and PCR. One vaccine strain (MIB187(T)) giving 100% protection (tested on only a few animals) was freeze dried and the minimum protective dose calculated. Changes in the virus genome after thermo-adaptation were examined using RT-PCR to amplify portions of the F gene, and three base changes were observed in the thermostable PPR strain (compared with the F gene sequence of the Nigerian PPRV strain). At room temperature, the titre and potency of the thermo-adapted vaccine remained constant up to one month at the10 5.5 TCID 50 level, and was 10 4.5 TCID 50 /100 μl after two months. Field trials with over 40 000 doses of the thermostable vaccine under various environmental conditions have given serum neutralization titres exceeding 2 3 and are assumed protective. (author)

Bioconversion of D-galactose to D-tagatose: continuous packed bed reaction with an immobilized thermostable L-arabinose isomerase and efficient purification by selective microbial degradation.

Science.gov (United States)

Liang, Min; Chen, Min; Liu, Xinying; Zhai, Yafei; Liu, Xian-wei; Zhang, Houcheng; Xiao, Min; Wang, Peng

2012-02-01

The continuous enzymatic conversion of D-galactose to D-tagatose with an immobilized thermostable L-arabinose isomerase in packed-bed reactor and a novel method for D-tagatose purification were studied. L-arabinose isomerase from Thermoanaerobacter mathranii (TMAI) was recombinantly overexpressed and immobilized in calcium alginate. The effects of pH and temperature on D-tagatose production reaction catalyzed by free and immobilized TMAI were investigated. The optimal condition for free enzyme was pH 8.0, 60°C, 5 mM MnCl(2). However, that for immobilized enzyme was pH 7.5, 75°C, 5 mM MnCl(2). In addition, the catalytic activity of immobilized enzyme at high temperature and low pH was significantly improved compared with free enzyme. The optimum reaction yield with immobilized TMAI increased by four percentage points to 43.9% compared with that of free TMAI. The highest productivity of 10 g/L h was achieved with the yield of 23.3%. Continuous production was performed at 70°C; after 168 h, the reaction yield was still above 30%. The resultant syrup was then incubated with Saccharomyces cerevisiae L1 cells. The selective degradation of D-galactose was achieved, obtaining D-tagatose with the purity above 95%. The established production and separation methods further potentiate the industrial production of D-tagatose via bioconversion and biopurification processes.

Production of thermostable and organic solvent-tolerant alkaline ...

African Journals Online (AJOL)

An alkaliphilic bacterium producing organic solvent-tolerant and thermostable alkaline protease was isolated from poultry litter site and identified as Bacillus coagulans PSB-07. Protease production under different submerged fermentation conditions were investigated with the aim of optimizing yield of enzyme. B. coagulans ...

Role of the L-citrulline/L-arginine cycle in iNANC nerve-mediated nitric oxide production and airway smooth muscle relaxation in allergic asthma

NARCIS (Netherlands)

Maarsingh, Ham; Leusink, John; Zaagsma, Johan; Meurs, Herman

2006-01-01

Nitric oxide synthase (NOS) converts L-arginine into nitric oxide (NO) and L-Citrulline. In NO-producing cells, L-citrulline can be recycled to L-arginine in a two-step reaction involving argininosuccinate synthase (ASS) and -lyase (ASL). In guinea pig trachea, L-arginine is a limiting factor in

The Tyrosine Aminomutase TAM1 Is Required for β-Tyrosine Biosynthesis in Rice

Science.gov (United States)

Yan, Jian; Aboshi, Takako; Teraishi, Masayoshi; Strickler, Susan R.; Spindel, Jennifer E.; Tung, Chih-Wei; Takata, Ryo; Matsumoto, Fuka; Maesaka, Yoshihiro; McCouch, Susan R.; Okumoto, Yutaka; Mori, Naoki; Jander, Georg

2015-01-01

Non-protein amino acids, often isomers of the standard 20 protein amino acids, have defense-related functions in many plant species. A targeted search for jasmonate-induced metabolites in cultivated rice (Oryza sativa) identified (R)-β-tyrosine, an isomer of the common amino acid (S)-α-tyrosine in the seeds, leaves, roots, and root exudates of the Nipponbare cultivar. Assays with 119 diverse cultivars showed a distinct presence/absence polymorphism, with β-tyrosine being most prevalent in temperate japonica cultivars. Genetic mapping identified a candidate gene on chromosome 12, which was confirmed to encode a tyrosine aminomutase (TAM1) by transient expression in Nicotiana benthamiana and in vitro enzyme assays. A point mutation in TAM1 eliminated β-tyrosine production in Nipponbare. Rice cultivars that do not produce β-tyrosine have a chromosome 12 deletion that encompasses TAM1. Although β-tyrosine accumulation was induced by the plant defense signaling molecule jasmonic acid, bioassays with hemipteran and lepidopteran herbivores showed no negative effects at physiologically relevant β-tyrosine concentrations. In contrast, root growth of Arabidopsis thaliana and other tested dicot plants was inhibited by concentrations as low as 1 μM. As β-tyrosine is exuded into hydroponic medium at higher concentrations, it may contribute to the allelopathic potential of rice. PMID:25901084

L-tyrosine immobilized on multiwalled carbon nanotubes: a new substrate for thallium separation and speciation using stabilized temperature platform furnace-electrothermal atomic absorption spectrometry.

Science.gov (United States)

Pacheco, Pablo H; Gil, Raúl A; Smichowski, Patricia; Polla, Griselda; Martinez, Luis D

2009-12-10

An approach for the separation and determination of inorganic thallium species is described. A new sorbent, L-tyrosine-carbon nanotubes (L-tyr-CNTs), was used and applied to the analysis of tap water samples. At pH 5.0, L-tyr was selective only towards Tl(III), while total thallium was determined directly by stabilized temperature platform furnace-electrothermal atomic absorption spectrometry (STPF-ETAAS). The Tl(III) specie, which was retained by L-tyrosine, was quantitatively eluted from the column with 10% of nitric acid. An on-line breakthrough curve was used to determine the column capacity, which resulted to be 9.00 micromol of Tl(III) g(-1) of L-tyr-CNTs with a molar ratio of 0.14 (moles of Tl bound to moles of L-tyr at pH 5). Transient peak areas revealed that Tl stripping from the column occurred instantaneously. Effects of sample flow rate, concentration and flow rate of the eluent, and interfering ions on the recovery of the analyte were systematically investigated. The detection limit for the determination of total thallium (3sigma) by STPF-ETAAS was 150 ng L(-1). The detection limit (3sigma) for Tl(III) employing the separation system was 3 ng L(-1), with an enrichment factor of 40. The precision of the method expressed as the relative standard deviation (RSD) resulted to be 3.4%. The proposed method was applied to the speciation and determination of inorganic thallium in tap water samples. The found concentrations were in the range of 0.88-0.91 microg L(-1) of Tl(III), and 3.69-3.91 microg L(-1) of total thallium.

L-Tyrosine immobilized on multiwalled carbon nanotubes: A new substrate for thallium separation and speciation using stabilized temperature platform furnace-electrothermal atomic absorption spectrometry

International Nuclear Information System (INIS)

Pacheco, Pablo H.; Gil, Raul A.; Smichowski, Patricia; Polla, Griselda; Martinez, Luis D.

2009-01-01

An approach for the separation and determination of inorganic thallium species is described. A new sorbent, L-tyrosine-carbon nanotubes (L-tyr-CNTs), was used and applied to the analysis of tap water samples. At pH 5.0, L-tyr was selective only towards Tl(III), while total thallium was determined directly by stabilized temperature platform furnace-electrothermal atomic absorption spectrometry (STPF-ETAAS). The Tl(III) specie, which was retained by L-tyrosine, was quantitatively eluted from the column with 10% of nitric acid. An on-line breakthrough curve was used to determine the column capacity, which resulted to be 9.00 μmol of Tl(III) g -1 of L-tyr-CNTs with a molar ratio of 0.14 (moles of Tl bound to moles of L-tyr at pH 5). Transient peak areas revealed that Tl stripping from the column occurred instantaneously. Effects of sample flow rate, concentration and flow rate of the eluent, and interfering ions on the recovery of the analyte were systematically investigated. The detection limit for the determination of total thallium (3σ) by STPF-ETAAS was 150 ng L -1 . The detection limit (3σ) for Tl(III) employing the separation system was 3 ng L -1 , with an enrichment factor of 40. The precision of the method expressed as the relative standard deviation (RSD) resulted to be 3.4%. The proposed method was applied to the speciation and determination of inorganic thallium in tap water samples. The found concentrations were in the range of 0.88-0.91 μg L -1 of Tl(III), and 3.69-3.91 μg L -1 of total thallium.

Bioremoval Capacity Of Phenol By Green Micro-Algal And Fungal Species Isolated From Dry Environment

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Abdullah T. Al-fawwaz

2015-08-01

Full Text Available Phenol is an organic hazardous pollutant that exerts toxic effects on living cells at relatively at low concentrations. Moreover accumulation of phenol exhibit toxicity towards the biotic components of the environment. Phenol bioremoval is a very useful approach to clean up the residual phenol from the environment. This study aims at isolating green microalgae and fungi from local dry environment to test their ability to remove phenol. Subsequently two green microalgal species have been isolated and identified as Desmodesmus sp. and Chlamydomonas sp.. Also two fungal species have been isolated and identified as Rhizopus sp. and Mucor sp. Phenol bioremoval capacity as well as the effects of some physicochemical factors on the bioremoval process were then studied. These factors include initial phenol concentration contact time and the synergistic effect Desmodesmus sp. and Rhizopus sp. on the bioremoval process. Both microalgae and fungi showed phenol bioremoval capacity. The highest phenol removal percentage among algae was found 75 by Desmodesmus sp. after 25 days at 25 mgL while the highest phenol removal percentage among fungi was found 86 by Rhizopus sp. after 25 days at 100 mgL. Bioremoval of phenol by the consortium Desmodesmus sp. and Rhizopus sp. was found to be 95 at the phenol concentration 25 mgL.

Quantification of Phenolic Compounds and In Vitro Radical Scavenging Abilities with Leaf Extracts from Two Varieties of Psidium guajava L.

Science.gov (United States)

Camarena-Tello, Julio César; Martínez-Flores, Héctor Eduardo; Garnica-Romo, Ma Guadalupe; Padilla-Ramírez, José Saúl; Saavedra-Molina, Alfredo; Alvarez-Cortes, Osvaldo; Bartolomé-Camacho, María Carmen; Rodiles-López, José Octavio

2018-02-27

Guava leaf ( Psidium guajava L.) extracts are used in both traditional medicine and the pharmaceutical industry. The antioxidant compounds in P. guajava leaves can have positive effects including anti-inflammatory, anti-hyperglycemic, hepatoprotective, analgesic, anti-cancer effects, as well as protecting against cardiovascular diseases. In the present study, phenolic compounds and in vitro antioxidant capacity were measured in extracts obtained with polar and non-polar solvents from leaves of two varieties of guava, Calvillo Siglo XXI and Hidrozac. The quantity of total phenolics and total flavonoids were expressed as equivalents of gallic acid and quercetin, respectively. Hydroxyl radical, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and Oxygen Radical Absorbance Capacity using fluorescein (ORAC-FL) in vitro tests were used to assess the radical scavenging abilities of the extracts. The total phenolics were higher in the aqueous fraction of the variety Calvillo Siglo XXI, while in the Hidrozac variety total phenolics were higher in the acetone and chloroform fractions. Total flavonoids were higher in all fractions in the variety Calvillo Siglo XXI. Total phenolics showed a highly positive correlation for ORAC-FL, and a moderately positive correlation with hydroxyl radicals. Finally, total flavonoids showed a slightly positive correlation for ORAC-FL and hydroxyl radicals. Both varieties of guava leaf extract showed excellent antioxidant properties.

Quantification of Phenolic Compounds and In Vitro Radical Scavenging Abilities with Leaf Extracts from Two Varieties of Psidium guajava L.

Directory of Open Access Journals (Sweden)

Julio César Camarena-Tello

2018-02-01

Full Text Available Guava leaf (Psidium guajava L. extracts are used in both traditional medicine and the pharmaceutical industry. The antioxidant compounds in P. guajava leaves can have positive effects including anti-inflammatory, anti-hyperglycemic, hepatoprotective, analgesic, anti-cancer effects, as well as protecting against cardiovascular diseases. In the present study, phenolic compounds and in vitro antioxidant capacity were measured in extracts obtained with polar and non-polar solvents from leaves of two varieties of guava, Calvillo Siglo XXI and Hidrozac. The quantity of total phenolics and total flavonoids were expressed as equivalents of gallic acid and quercetin, respectively. Hydroxyl radical, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS, 2,2-diphenyl-1-picrylhydrazyl (DPPH, and Oxygen Radical Absorbance Capacity using fluorescein (ORAC-FL in vitro tests were used to assess the radical scavenging abilities of the extracts. The total phenolics were higher in the aqueous fraction of the variety Calvillo Siglo XXI, while in the Hidrozac variety total phenolics were higher in the acetone and chloroform fractions. Total flavonoids were higher in all fractions in the variety Calvillo Siglo XXI. Total phenolics showed a highly positive correlation for ORAC-FL, and a moderately positive correlation with hydroxyl radicals. Finally, total flavonoids showed a slightly positive correlation for ORAC-FL and hydroxyl radicals. Both varieties of guava leaf extract showed excellent antioxidant properties.

Quantification of Phenolic Compounds and In Vitro Radical Scavenging Abilities with Leaf Extracts from Two Varieties of Psidium guajava L.

Science.gov (United States)

Martínez-Flores, Héctor Eduardo; Garnica-Romo, Ma. Guadalupe; Padilla-Ramírez, José Saúl; Saavedra-Molina, Alfredo; Alvarez-Cortes, Osvaldo; Bartolomé-Camacho, María Carmen; Rodiles-López, José Octavio

2018-01-01

Guava leaf (Psidium guajava L.) extracts are used in both traditional medicine and the pharmaceutical industry. The antioxidant compounds in P. guajava leaves can have positive effects including anti-inflammatory, anti-hyperglycemic, hepatoprotective, analgesic, anti-cancer effects, as well as protecting against cardiovascular diseases. In the present study, phenolic compounds and in vitro antioxidant capacity were measured in extracts obtained with polar and non-polar solvents from leaves of two varieties of guava, Calvillo Siglo XXI and Hidrozac. The quantity of total phenolics and total flavonoids were expressed as equivalents of gallic acid and quercetin, respectively. Hydroxyl radical, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and Oxygen Radical Absorbance Capacity using fluorescein (ORAC-FL) in vitro tests were used to assess the radical scavenging abilities of the extracts. The total phenolics were higher in the aqueous fraction of the variety Calvillo Siglo XXI, while in the Hidrozac variety total phenolics were higher in the acetone and chloroform fractions. Total flavonoids were higher in all fractions in the variety Calvillo Siglo XXI. Total phenolics showed a highly positive correlation for ORAC-FL, and a moderately positive correlation with hydroxyl radicals. Finally, total flavonoids showed a slightly positive correlation for ORAC-FL and hydroxyl radicals. Both varieties of guava leaf extract showed excellent antioxidant properties. PMID:29495514

Changes in antioxidant activity, total phenolic and abscisic acid constituents in the aquatic plants Myriophyllum spicatum L. and Myriophyllum triphyllum Orchard exposed to cadmium.

Science.gov (United States)

Sivaci, Aysel; Sivaci, E Ridvan; Sökmen, Münevver

2007-07-01

Changes in antioxidant activity, total phenolic and abscisic acid (ABA) constituents of Myriophyllum spicatum L. and Myriophyllum triphyllum Orchard, cadmium (Cd) aqueous macrophytes, were investigated exposed to 0, 2, 4, 6, 8, 16 mg l(-1) Cd concentrations. M. triphyllum exhibited strong antioxidant activity but not M. spicatum before and after exposure. Free radical scavenging activity of M. triphyllum was significantly affected from the Cd concentrations and a significant increase was observed at 6 mgl(-1) Cd concentration. Total phenolic constituent and ABA concentration of M. triphyllum is higher than that of M. spicatum with or without heavy metal exposure (P macrophytes that grown in polluted aqueous ecosystem.

Variations of total phenol, carotenoid, in vitro antioxidant contents, and phenolic profiles of the pulp of five commercial varieties of mango

Science.gov (United States)

Mango (Mangifera indica L.) is a tropical fruit crop grown worldwide with widely attributed nutritional and health-promoting properties. Extensive studies have been made of the high concentrations of phenolic antioxidants in the peel, seeds, and leaves of mango, yet less is known about the phenolic ...

Assessment of (poly)phenols in grape (Vitis vinifera L.) stems by using food/pharma industry compatible solvents and Response Surface Methodology.

Science.gov (United States)

Domínguez-Perles, R; Teixeira, A I; Rosa, E; Barros, A I

2014-12-01

A Box-Behnken design of Response Surface Methodology (RSM) was conducted to analyse the effect of time (10-30 min), temperature (25-95°C), and solvents concentration (5-90%) on the extraction of total phenolics, flavonoids, ortho-diphenols, and anthocyanins as well as to assess the ABTS(+) scavenging capacity, which were considered as response variables. Values coefficients of determination (R(2)), ranging from 0.903 to 0.996, fitted for describing efficient extraction of bioactive (poly)phenols and antioxidant activity. The recorded data allowed to establish the optimal extraction conditions at 23.0 min, 95.0°C, and 57.9% of food-quality ethanol/water for Vitis vinifera L. var. 'Viosinho' (white variety), and 23.4 min, 84.2°C, and 63.8% for var. 'Touriga Nacional' (red variety). The achievement of optimal extraction conditions of phenolics from grape stems using solvents compatible with further uses in food/pharma industries demonstrated that RSM constitutes a powerful tool for deriving optimal conditions for extraction of antioxidant phenolic compounds from grape stems. Copyright © 2014 Elsevier Ltd. All rights reserved.

Changes in the concentrations of phenolics and photosynthates in Scots pine (Pinus sylvestris L.) seedlings exposed to nickel and copper

Energy Technology Data Exchange (ETDEWEB)

Roitto, M. [MTT Agrifood Research Finland, Environmental Research, Karilantie 2A, FIN-50600 Mikkeli (Finland) and Department of Ecological and Environmental Sciences, University of Helsinki, Niemenkatu 73, FIN-15140 Lahti (Finland)]. E-mail: marja.roitto@mtt.fi; Rautio, P. [Finnish Forest Research Institute, Parkano Research Station, Kaironiementie 54, FIN-39700 Parkano (Finland); Julkunen-Tiitto, R. [Department of Biology, University of Joensuu, PO Box 111, FIN-80101 Joensuu (Finland); Kukkola, E. [University of Helsinki, Department of Biosciences, Division of Plant Physiology, PO Box 56, FIN-00014, Helsinki (Finland); Huttunen, S. [Department of Biology, University of Oulu, PO Box 3000, FIN-90014 Oulu (Finland)

2005-10-15

Studies were done on the effects of elevated soil concentrations of copper (Cu) and (Ni) on foliar carbohydrates and phenolics in Scots pine (Pinus sylvestris L.). Four year-old seedlings were planted in pots filled with metal-treated mineral forest soil in early June. The experimental design included all combinations of four levels of Cu (0, 25, 40 and 50 mg kg{sup -1} soil dw) and Ni (0, 5, 15 and 25 mg kg{sup -1} soil dw). Current year needles were sampled for soluble sugar, starch and phenolics at the end of September. Ni increased sucrose concentration in the needles, indicating disturbances in carbohydrate metabolism. Trees exposed to Ni had higher concentrations of condensed tannins compared with controls. In contrast, concentrations of several other phenolic compounds decreased when seedlings were exposed to high levels of Cu or to a combination of Ni and Cu. The results suggest that concentrations of phenolics in Scots pine needles vary in their responses to Ni and Cu in the forest soil. - Excess nickel in soil interferes with carbohydrate metabolism and induces an increase in concentration of condensed tannins in Scots pine needles.

Changes in the concentrations of phenolics and photosynthates in Scots pine (Pinus sylvestris L.) seedlings exposed to nickel and copper

International Nuclear Information System (INIS)

Roitto, M.; Rautio, P.; Julkunen-Tiitto, R.; Kukkola, E.; Huttunen, S.

2005-01-01

Studies were done on the effects of elevated soil concentrations of copper (Cu) and (Ni) on foliar carbohydrates and phenolics in Scots pine (Pinus sylvestris L.). Four year-old seedlings were planted in pots filled with metal-treated mineral forest soil in early June. The experimental design included all combinations of four levels of Cu (0, 25, 40 and 50 mg kg -1 soil dw) and Ni (0, 5, 15 and 25 mg kg -1 soil dw). Current year needles were sampled for soluble sugar, starch and phenolics at the end of September. Ni increased sucrose concentration in the needles, indicating disturbances in carbohydrate metabolism. Trees exposed to Ni had higher concentrations of condensed tannins compared with controls. In contrast, concentrations of several other phenolic compounds decreased when seedlings were exposed to high levels of Cu or to a combination of Ni and Cu. The results suggest that concentrations of phenolics in Scots pine needles vary in their responses to Ni and Cu in the forest soil. - Excess nickel in soil interferes with carbohydrate metabolism and induces an increase in concentration of condensed tannins in Scots pine needles

Exploring oxidative modifications of tyrosine

DEFF Research Database (Denmark)

Houée-Lévin, C; Bobrowski, K; Horakova, L

2015-01-01

residues are oxidised in vivo with impact on cellular homeostasis and redox signalling pathways. A notable example is tyrosine, which can undergo a number of oxidative post-translational modifications to form 3-hydroxy-tyrosine, tyrosine crosslinks, 3-nitrotyrosine and halogenated tyrosine, with different...... effects on cellular functions. Tyrosine oxidation has been studied extensively in vitro, and this has generated detailed information about the molecular mechanisms that may occur in vivo. An important aspect of studying tyrosine oxidation both in vitro and in biological systems is the ability to monitor...... residues modified and the nature of the modification. These approaches have helped understanding of the consequences of tyrosine oxidation in biological systems, especially its effects on cell signalling and cell dysfunction, linking to roles in disease. There is mounting evidence that tyrosine oxidation...

A novel non-thermostable deuterolysin from Aspergillus oryzae.

Science.gov (United States)

Maeda, Hiroshi; Katase, Toru; Sakai, Daisuke; Takeuchi, Michio; Kusumoto, Ken-Ichi; Amano, Hitoshi; Ishida, Hiroki; Abe, Keietsu; Yamagata, Youhei

2016-09-01

Three putative deuterolysin (EC 3.4.24.29) genes (deuA, deuB, and deuC) were found in the Aspergillus oryzae genome database ( http://www.bio.nite.go.jp/dogan/project/view/AO ). One of these genes, deuA, was corresponding to NpII gene, previously reported. DeuA and DeuB were overexpressed by recombinant A. oryzae and were purified. The degradation profiles against protein substrates of both enzymes were similar, but DeuB showed wider substrate specificity against peptidyl MCA-substrates compared with DeuA. Enzymatic profiles of DeuB except for thermostability also resembled those of DeuA. DeuB was inactivated by heat treatment above 80° C, different from thermostable DeuA. Transcription analysis in wild type A. oryzae showed only deuB was expressed in liquid culture, and the addition of the proteinous substrate upregulated the transcription. Furthermore, the NaNO3 addition seems to eliminate the effect of proteinous substrate for the transcription of deuB.

AKTIVITAS ANTIOKSIDAN DAN KADAR FENOLIK TOTAL DARI GANGGANG MERAH (Gracilaria verrucosa L. [Antioxidant Activity and Total Phenolic Content of Red Sea Weed (Gracilaria verrucosa L.

Directory of Open Access Journals (Sweden)

Lydia Ninan Lestario*

2008-12-01

Full Text Available The aims of this study were to compare the antioxidant activity and the total phenolic content of red sea weed (Gracilaria verrucosa L. from extract of methanol, ethanol, acetone, chloroform and hexane; and the correlation between total phenolic content and the antioxidant activity of each extract; then to determine the chlorophyll a, chlorophyll b, and carotene content of each extract and their correlation with the free radical scavenging activity as well. The antioxidant activity were measured by free radical scavenging method with DPPH and by reducing power method with K4Fe(CN6 as standard, whereas the total phenolic content was measured by Folin Ciocalteu method with gallic acid as standard. Chlorophyll a, chlorophyll b, and carotene were determined by spectrophotometric method based on Lambert-Beer law. The data of antioxidant activity and total phenolic content were statistically analyzed by Randomized Completely Block Design (RCBD with five kinds of solvents as treatments and five replications. Honestly Significant Difference Test (HSDT was used to compare the difference of treatments; whereas the chlorophyll a, chlorophyll b, and carotene content were not statistically analyzed since they were only supplement data. The results showed that the highest of the antioxidant activity by free radical scavenging method was found in acetone extract : 43.43% (BHT: 84.15%; whereas by reducing power method was found in chloroform extract : 0.1756 meq K4Fe(CN6/g extract (BHT : 6.1767 meq K4Fe(CN6/g extract; and the highest of the total phenolic content was also found in acetone extract : 45.29 mg /g extract. There were close correlation between phenolic content and antioxidant activity both by free radical scavenging method and by reducing power method with r (coefficient correlation respectivelly 0.89 and 0.91.Chlorophyll a and carotene had also close correlation with the free radical scaveging activity, but not for chlorophyll b.

Structure of a thermostable serralysin from Serratia sp. FS14 at 1.1 Å resolution.

Science.gov (United States)

Wu, Dongxia; Ran, Tinting; Wang, Weiwu; Xu, Dongqing

2016-01-01

Serralysin is a well studied metalloprotease, and typical serralysins are not thermostable. The serralysin isolated from Serratia sp. FS14 was found to be thermostable, and in order to reveal the mechanism responsible for its thermostability, the crystal structure of serralysin from Serratia sp. FS14 was solved to a crystallographic R factor of 0.1619 at 1.10 Å resolution. Similar to its homologues, it mainly consists of two domains: an N-terminal catalytic domain and a `parallel β-roll' C-terminal domain. Comparative studies show that the shape of the catalytic active-site cavity is more open owing to the 189-198 loop, with a short 310-helix protruding further from the molecular surface, and that the β-sheets comprising the `parallel β-roll' are longer than those in its homologues. The formation of hydrogen bonds from one of the nonconserved residues (Asn200) to Lys27 may contribute to the thermostability.

Determination of contents and antioxidant activity of free and bound phenolics compounds and in vitro digestibility of commercial black and red rice (Oryza sativa L.) varieties.

Science.gov (United States)

Sumczynski, Daniela; Kotásková, Eva; Družbíková, Helena; Mlček, Jiří

2016-11-15

Black and red rices (Oryza sativa L.) were analysed for total flavonoids and phenolics and the HPLC profile including both free and bound phenolic fractions. Moreover, antioxidant activity and in vitro digestibility was determined. Content of flavonoids and polyphenols as well as antioxidant activity was higher in free phenolic fractions. Bound flavonoids in black rices were not significant contributors to antioxidant activity. The main free phenolics in black rices were ferulic, protocatechuic and trans-p-coumaric acids, while the major free phenolics in red rices were catechin, protocatechuic and caffeic acids. The main bound phenolics in black rices were ferulic and vanillic acids and quercetin, in red rice types, they were ferulic, syringic, trans-p-coumaric acids and quercetin. Newly, the presence of m-coumaric acid in red rices was detected. Steam cooked rices showed very high levels of organic matter digestibility, whereas red rices were significantly more digestible than black rices (p<0.05). Copyright © 2016 Elsevier Ltd. All rights reserved.

Highly thermostable fluorescent proteins

Science.gov (United States)

Bradbury, Andrew M [Santa Fe, NM; Waldo, Geoffrey S [Santa Fe, NM; Kiss, Csaba [Los Alamos, NM

2011-03-22

Thermostable fluorescent proteins (TSFPs), methods for generating these and other stability-enhanced proteins, polynucleotides encoding such proteins, and assays and method for using the TSFPs and TSFP-encoding nucleic acid molecules are provided. The TSFPs of the invention show extremely enhanced levels of stability and thermotolerance. In one case, for example, a TSFP of the invention is so stable it can be heated to 99.degree. C. for short periods of time without denaturing, and retains 85% of its fluorescence when heated to 80.degree. C. for several minutes. The invention also provides a method for generating stability-enhanced variants of a protein, including but not limited to fluorescent proteins.

Effect of solvent on the extraction of phenolic compounds and antioxidant capacity of hazelnut kernel.

Science.gov (United States)

Fanali, Chiara; Tripodo, Giusy; Russo, Marina; Della Posta, Susanna; Pasqualetti, Valentina; De Gara, Laura

2018-03-22

Hazelnut kernel phenolic compounds were recovered applying two different extraction approaches, namely ultrasound-assisted solid/liquid extraction (UA-SLE) and solid-phase extraction (SPE). Different solvents were tested evaluating total phenolic compounds and total flavonoids contents together to antioxidant activity. The optimum extraction conditions, in terms of the highest value of total phenolic compounds extracted together to other parameters like simplicity and cost were selected for method validation and individual phenolic compounds analysis. The UA-SLE protocol performed using 0.1 g of defatted sample and 15 mL of extraction solvent (1 mL methanol/1 mL water/8 mL methanol 0.1% formic acid/5 mL acetonitrile) was selected. The analysis of hazelnut kernel individual phenolic compounds was obtained by HPLC coupled with DAD and MS detections. Quantitative analysis was performed using a mixture of six phenolic compounds belonging to phenolic classes' representative of hazelnut. Then, the method was fully validated and the resulting RSD% values for retention time repeatability were below 1%. A good linearity was obtained giving R 2 no lower than 0.997.The accuracy of the extraction method was also assessed. Finally, the method was applied to the analysis of phenolic compounds in three different hazelnut kernel varieties observing a similar qualitative profile with differences in the quantity of detected compounds. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrochemical removal of phenol from oil refinery wastewater.

Science.gov (United States)

Abdelwahab, O; Amin, N K; El-Ashtoukhy, E-S Z

2009-04-30

This study explores the possibility of using electrocoagulation to remove phenol from oil refinery waste effluent using a cell with horizontally oriented aluminum cathode and a horizontal aluminum screen anode. The removal of phenol was investigated in terms of various parameters namely: pH, operating time, current density, initial phenol concentration and addition of NaCl. Removal of phenol during electrocoagulation was due to combined effect of sweep coagulation and adsorption. The results showed that, at high current density and solution pH 7, remarkable removal of 97% of phenol after 2h can be achieved. The rate of electrocoagulation was observed to increase as the phenol concentration decreases; the maximum removal rate was attained at 30 mg L(-1) phenol concentration. For a given current density using an array of closely packed Al screens as anode was found to be more effective than single screen anode, the percentage phenol removal was found to increase with increasing the number of screens per array. After 2h of electrocoagulation, 94.5% of initial phenol concentration was removed from the petroleum refinery wastewater. Energy consumption and aluminum Electrode consumption were calculated per gram of phenol removed. The present study shows that, electrocoagulation of phenol using aluminum electrodes is a promising process.

Wine phenolic compounds influence the production of volatile phenols by wine-related lactic acid bacteria.

Science.gov (United States)

Silva, I; Campos, F M; Hogg, T; Couto, J A

2011-08-01

To evaluate the effect of wine phenolic compounds on the production of volatile phenols (4-vinylphenol [4VP] and 4-ethylphenol [4EP]) from the metabolism of p-coumaric acid by lactic acid bacteria (LAB). Lactobacillus plantarum, Lactobacillus collinoides and Pediococcus pentosaceus were grown in MRS medium supplemented with p-coumaric acid, in the presence of different phenolic compounds: nonflavonoids (hydroxycinnamic and benzoic acids) and flavonoids (flavonols and flavanols). The inducibility of the enzymes involved in the p-coumaric acid metabolism was studied in resting cells. The hydroxycinnamic acids tested stimulated the capacity of LAB to synthesize volatile phenols. Growth in the presence of hydroxycinnamic acids, especially caffeic acid, induced the production of 4VP by resting cells. The hydroxybenzoic acids did not significantly affect the behaviour of the studied strains. Some of the flavonoids showed an effect on the production of volatile phenols, although strongly dependent on the bacterial species. Relatively high concentrations (1 g l(-1) ) of tannins inhibited the synthesis of 4VP by Lact. plantarum. Hydroxycinnamic acids were the main compounds stimulating the production of volatile phenols by LAB. The results suggest that caffeic and ferulic acids induce the synthesis of the cinnamate decarboxylase involved in the metabolism of p-coumaric acid. On the other hand, tannins exert an inhibitory effect. This study highlights the capacity of LAB to produce volatile phenols and that this activity is markedly influenced by the phenolic composition of the medium. © 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology.

Seasonal variation in the phenol content of Eugenia uniflora L. leaves

OpenAIRE

Santos, R.M; Oliveira, M.S; Ferri, P.H; Santos, S.C

2011-01-01

Hydrolysable tannins, total phenols and flavonoids in Eugenia uniflora leaves were monthly analysed for one year. The results were correlated with climate conditions (rainfall, humidity, cloudiness and mean temperature) through chemometric methods. Principal component analysis revealed high levels of hydrolysable tannins in the rainy season, whereas flavonoids were mainly produced in the dry season. These facts suggest that climatic changes may be one of the factors affecting phenol levels in...

Extracellular laccase production and phenolic degradation by an olive mill wastewater isolate

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R. Kumar

2018-03-01

Full Text Available Olive mill wastewater (OMWW presents a challenge to the control of effluents due to the presence of a high organic load, antimicrobial agents (monomeric-polymeric phenols, volatile acids, polyalcohols, and tannins, salinity and acidity. In this study, the production of extracellular laccase, monomeric or polymeric phenol, from an OMWW isolate based on its ability to biodegrade phenols and gallic acid as a model of phenolic compounds in OMWW was investigated. Phylogenetic analysis of the 16S RNA gene sequences identified the bacterial isolate (Acinetobacter REY as being closest to Acinetobacter pittii. This isolate exhibited a constitutive production of extracellular laccase with an activity of 1.5 and 1.3 U ml/L when supplemented with the inducers CuSO4 and CuSO4+phenols, respectively. Batch experiments containing minimal media supplemented with phenols or gallic acid as the sole carbon and energy source were performed in order to characterize their phenolic biodegradability. Acinetobacter REY was capable of biodegrading up to 200 mg/L of phenols and gallic acid both after 10 h and 72 h, respectively.

[Branch-specific detection of phenols and assessment of ground water solubility].

Science.gov (United States)

Fischer, F; Kerndorff, H; Kühn, S

2000-01-01

compounds are known. Poisoning due to oral uptake of phenol contaminated ground- or drinking water have not been reported, which might be due to the pungent odor and taste phenolic compounds have even at very low concentrations (mg/L). Because of the taste problem, the German drinking water standard for phenols is 0.5 microgram/L. In Berlin, groundwater with phenol concentrations higher than 30 micrograms/L of alkylphenols or 2 micrograms/L of chlorophenols is considered contaminated.

Cystathionine .gamma.-lyase: Clinical, metabolic, genetic, and structural studies

Czech Academy of Sciences Publication Activity Database

Kraus, J. P.; Hašek, Jindřich; Kožich, V.; Collard, R.; Venezia, S.; Janošíková, B.; Wang, J.; Stabler, S. P.; Allen, R. H.; Jakobs, C.; Finn, C. T.; Chien, Y. H.; Hwu, W. L.; Hegele, R. A.; Mudd, S. H.

2009-01-01

Roč. 97, č. 4 (2009), s. 250-259 ISSN 1096-7192 R&D Projects: GA ČR GA305/07/1073 Institutional research plan: CEZ:AV0Z40500505 Keywords : cystathionine gamma-lyase * cystathioninuria * hypercystathioninemia Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.897, year: 2009

Effect of tyrosine administration on duodenal ulcer induced by cysteamine in the rat

International Nuclear Information System (INIS)

Oishi, T.; Szabo, S.

1987-01-01

Duodenal ulcers were produced by administering cysteamine to rats. Pretreatment with the catecholamine precursor, L-tyrosine (40 mg/100 g i.p. for 5 days), decreased the intensity of duodenal ulcers induced by cysteamine. Equimolar doses of tyrosine methyl ester (51.2 mg/100 g i.p. or s.c.) were equally effective in reducing ulcer intensity. Other amino acids (i.e., alanine, aspartic acid, glutamic acid, glycine, leucine, lysine, tryptophan and valine) did not prevent experimental duodenal ulcers. Coadministration of other large neutral amino acids (e.g., leucine and valine) that compete with tyrosine for uptake into the brain did not inhibit the effect of tyrosine on duodenal ulcers induced by cysteamine. Gastric, duodenal and brain dopamine concentrations were increased 1 hr after the injection of tyrosine methyl ester (25.6 mg/100 g s.c.). These results suggest that the effect of tyrosine on duodenal ulcer induced by cysteamine may be mediated by changes in gastrointestinal dopamine metabolism

Drying Methods Alter Angiotensin-I Converting Enzyme Inhibitory Activity, Antioxidant Properties, and Phenolic Constituents of African Mistletoe (Loranthus bengwensis L) Leaves.

Science.gov (United States)

Oboh, Ganiyu; Omojokun, Olasunkanmi Seun; Ademiluyi, Adedayo Oluwaseun

2016-10-01

This study investigated the most appropriate drying method (sun drying, oven drying, or air drying) for mistletoe leaves obtained from almond tree. The phenolic constituents were characterized using high-performance liquid chromatography-diode array detector, while the inhibitory effect of the aqueous extracts of the leaves on angiotensin-I converting enzyme (ACE) was determined in vitro as also the antioxidant properties. Oven-dried extract (kidney [276.09 μg/mL] and lungs [303.41 μg/mL]) had the highest inhibitory effect on ACE, while air-dried mistletoe extract (kidney [304.47 μg/mL] and lungs [438.72 μg/mL]) had the least. Furthermore, the extracts dose-dependently inhibited Fe(2+) and sodium nitroprusside-induced lipid peroxidation in rat's heart and kidney. Also, all extracts exhibited antioxidative properties as typified by their radical scavenging and Fe-chelating ability. Findings from this study revealed that oven drying is the best of the 3 drying methods used for mistletoe obtained from almond host tree, thus confirming that diversity in drying methods leads to variation in phenolic constituents and biological activity of plants. © The Author(s) 2015.

Variability of Virgin Olive Oil Phenolic Compounds in a Segregating Progeny from a Single Cross in Olea europaea L. and Sensory and Nutritional Quality Implications

Science.gov (United States)

Pérez, Ana G.; León, Lorenzo; Pascual, Mar; Romero-Segura, Carmen; Sánchez-Ortiz, Araceli; de la Rosa, Raúl; Sanz, Carlos

2014-01-01

Virgin olive oil phenolic compounds are responsible for its nutritional and sensory quality. The synthesis of phenolic compounds occurs when enzymes and substrates meet as olive fruit is crushed during the industrial process to obtain the oil. The genetic variability of the major phenolic compounds of virgin olive oil was studied in a progeny of the cross of Picual x Arbequina olive cultivars (Olea europaea L.). They belong to four different groups: compounds that included tyrosol or hydroxytyrosol in their molecules, lignans, flavonoids, and phenolic acids. Data of phenolics in the oils showed that the progeny displayed a large degree of variability, widely transgressing the genitor levels. This high variability can be of interest on breeding programs. Thus, multivariate analysis allowed to identify genotypes within the progeny particularly interesting in terms of phenolic composition and deduced organoleptic and nutritional quality. The present study has demonstrated that it is possible to obtain enough degree of variability with a single cross of olive cultivars for compounds related to the nutritional and organoleptic properties of virgin olive oil. PMID:24651694

Variability of virgin olive oil phenolic compounds in a segregating progeny from a single cross in Olea europaea L. and sensory and nutritional quality implications.

Science.gov (United States)

Pérez, Ana G; León, Lorenzo; Pascual, Mar; Romero-Segura, Carmen; Sánchez-Ortiz, Araceli; de la Rosa, Raúl; Sanz, Carlos

2014-01-01

Virgin olive oil phenolic compounds are responsible for its nutritional and sensory quality. The synthesis of phenolic compounds occurs when enzymes and substrates meet as olive fruit is crushed during the industrial process to obtain the oil. The genetic variability of the major phenolic compounds of virgin olive oil was studied in a progeny of the cross of Picual x Arbequina olive cultivars (Olea europaea L.). They belong to four different groups: compounds that included tyrosol or hydroxytyrosol in their molecules, lignans, flavonoids, and phenolic acids. Data of phenolics in the oils showed that the progeny displayed a large degree of variability, widely transgressing the genitor levels. This high variability can be of interest on breeding programs. Thus, multivariate analysis allowed to identify genotypes within the progeny particularly interesting in terms of phenolic composition and deduced organoleptic and nutritional quality. The present study has demonstrated that it is possible to obtain enough degree of variability with a single cross of olive cultivars for compounds related to the nutritional and organoleptic properties of virgin olive oil.

Highly thermostable xylanase production from a thermophilic Geobacillus sp. strain WSUCF1 utilizing lignocellulosic biomass

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Aditya eBhalla

2015-06-01

Full Text Available AbstractEfficient enzymatic hydrolysis of lignocellulose to fermentable sugars requires a complete repertoire of biomass deconstruction enzymes. Hemicellulases play an important role in hydrolyzing hemicellulose component of lignocellulose to xylo-oligosaccharides and xylose. Thermostable xylanases have been a focus of attention as industrially important enzymes due to their long shelf life at high temperatures. Geobacillus sp. strain WSUCF1 produced thermostable xylanase activity (crude xylanase cocktail when grown on xylan or various inexpensive untreated and pretreated lignocellulosic biomasses such as prairie cord grass and corn stover. The optimum pH and temperature for the crude xylanase cocktail were 6.5 and 70ºC, respectively. The WSUCF1 crude xylanase was found to be highly thermostable with half-lives of 18 and 12 days at 60 and 70ºC, respectively. At 70ºC, rates of xylan hydrolysis were also found to be better with the WSUCF1 secretome than those with commercial enzymes, i.e., for WSUCF1 crude xylanase, CellicHTec2, and AccelleraseXY, the percent xylan conversions were 68.9, 49.4, and 28.92, respectively. To the best of our knowledge, WSUCF1 crude xylanase cocktail is among the most thermostable xylanases produced by thermophilic Geobacillus spp. and other thermophilic microbes (optimum growth temperature ≤70ºC. High thermostability, activity over wide range of temperatures, and better xylan hydrolysis than commercial enzymes make WSUCF1 crude xylanase suitable for thermophilic lignocellulose bioconversion processes.

Optimization of phenol biodegradation by efficient bacteria isolated from petrochemical effluents

Directory of Open Access Journals (Sweden)

M. Shahriari Moghadam

2016-05-01

Full Text Available Phenol is an environmental pollutant present in industrial wastewaters such as refineries, coal processing and petrochemicals products. In this study three phenol degrading bacteria from Arak Petrochemical Complex effluent were isolated which consume phenol. Molecular analysis was used to identify bacteria and isolated bacteria were identified as Rhodococcus pyridinivorans (NS1, Advenella faeciporci (NS2 and Pseudomonas aeroginosa (NS3. Among the isolated strains, NS1 had the highest ability to degrade phenol. In order to observe the best yield in phenol biodegradation using NS1, optimization was performed using one factor at a time of experimental design to investigate the effect of four factors, including pH, temperature, phosphate and urea concentration. The optimal biodegradation condition through or tho pathway was pH = 8, urea = 1 g/L, temperature = 30°C and K2HPO4 = 0.5 g/L. Under the suggested condition, a biodegradation efficiency of 100% was achieved. Moreover, NS1 has shown growth and phenol degradation in concentrations between 250 to 2000 mg/L. In a nutshell, the results revealed thatphenol efficiently consumed by NS1 as the sole carbon source. Obviously, the isolate strain may be seen as an important tool in the bioremediation of wastewater effluent, petrochemical complex.

Enzymatic liquefaction of agarose above the sol-gel transition temperature using a thermostable endo-type β-agarase, Aga16B.

Science.gov (United States)

Kim, Jung Hyun; Yun, Eun Ju; Seo, Nari; Yu, Sora; Kim, Dong Hyun; Cho, Kyung Mun; An, Hyun Joo; Kim, Jae-Han; Choi, In-Geol; Kim, Kyoung Heon

2017-02-01

The main carbohydrate of red macroalgae is agarose, a heterogeneous polysaccharide composed of D-galactose and 3,6-anhydro-L-galactose. When saccharifying agarose by enzymes, the unique physical properties of agarose, namely the sol-gel transition and the near-insolubility of agarose in water, limit the accessibility of agarose to the enzymes. Due to the lower accessibility of agarose to enzymes in the gel state than to the sol state, it is important to prevent the sol-gel transition by performing the enzymatic liquefaction of agarose at a temperature higher than the sol-gel transition temperature of agarose. In this study, a thermostable endo-type β-agarase, Aga16B, originating from Saccharophagus degradans 2-40 T , was characterized and introduced in the liquefaction process. Aga16B was thermostable up to 50 °C and depolymerized agarose mainly into neoagarooligosaccharides with degrees of polymerization 4 and 6. Aga16B was applied to enzymatic liquefaction of agarose at 45 °C, which was above the sol-gel transition temperature of 1 % (w/v) agarose (∼35 °C) when cooling agarose. This is the first systematic demonstration of enzymatic liquefaction of agarose, enabled by determining the sol-gel temperature of agarose under specific conditions and by characterizing the thermostability of an endo-type β-agarase.

Thermostable Subunit Vaccines for Pulmonary Delivery: How Close Are We?

DEFF Research Database (Denmark)

Foged, Camilla

2016-01-01

, such as influenza, tuberculosis, and Ebola, for which no good universal vaccines exist. At least two pharmaceutical improvements are expected to help filling this gap: i) The development of thermostable vaccine dosage forms, and ii) the full exploitation of the adjuvant technology for subunit vaccines to potentiate...... strong immune responses. This review highlights the status and recent advances in formulation and pulmonary delivery of thermostable human subunit vaccines. Such vaccines are very appealing from compliance, distribution and immunological point of view: Being non-invasive, inhalable vaccines are self...... immunity. Here, I review state of the art and perspectives in formulation design and processing methods for powder-based subunit vaccines intended for pulmonary administration, and present dry powder inhaler technologies suitable for translating these vaccines into clinical trials....

Alkylperoxyl radical scavenging activity of red leaf lettuce (Lactuca sativa L.) phenolics.

Science.gov (United States)

Caldwell, Charles R

2003-07-30

Although lettuce may provide relatively low levels of antioxidative phytochemicals which may contribute to human health, lettuce leaf extracts in fact contained compounds with high specific peroxyl radical scavenging activities. After determining the extraction conditions that minimized phenolic oxidation and produced the highest oxygen radical absorbance capacity (ORAC) values, the phenolic compounds from red leaf lettuce were separated by reverse-phase high-performance liquid chromatography (HPLC). The primary phenolic compounds in the leaf tissue extracts were mono- and dicaffeoyltartaric acid (CTA and DCTA), mono- and dicaffeoylquinic acid (CQA and DCQA), quercetin 3-malonylglucoside (QMG), quercetin 3-glucoside (QG), cyanidin 3-malonylglucoside (CMG), and an unknown phenolic ester (UPE). Significant levels of DCQA were only found after wounding. Using the new fluorescein-based ORAC assay procedures, fractions from the HPLC analyses were assayed for peroxyl radical absorbance capacity. Using absorbance to estimate concentration, the decreasing order of contribution to the total ORAC value of an extract from wounded tissue was QMG > DCQA > CMG > DCTA > UPE > QG > CTA. The decreasing order of the specific peroxyl radical scavenging activities was CMG > QG > DCTA > DCQA > QMG > UPE > CQA > CTA. Since the concentrations of plant flavonoid and phenolic acid esters are sensitive to environmental factors, this information may be used to develop pre- and postharvest conditions which increase the dietary benefits of leaf lettuce.

Hematopoietic sphingosine 1-phosphate lyase deficiency decreases atherosclerotic lesion development in LDL-receptor deficient mice.

Directory of Open Access Journals (Sweden)

Martine Bot