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1

Comparison of Growth Performance and Whole-body Amino Acid Composition in Red Seabream (Pagrus major) Fed Free or Dipeptide Form of Phenylalanine  

PubMed Central

This study was conducted to evaluate the efficacy of the dipeptide form of phenylalanine as a new source of amino acid in terms of growth performance and whole-body amino acid composition in comparison to the free form for red seabream (Pagrus major). Fish (1.46±0.001 g) were fed four isonitrogenous and isocaloric experimental diets containing 0.7 or 1.4% phenylalanine either in free or dipeptide form. A feeding trial was carried out in three replicates and the fish were fed to apparent satiation for six weeks. At the end of the feeding trial, feed intake of fish was influenced by both phenylalanine form and level and significantly higher values were obtained at an inclusion level of 0.7% and by the use of dipeptide form. However, the other growth parameters did not significantly differ among treatments. Whole-body amino acid compositions revealed no significant changes in concentrations of both essential and non-essential amino acids regardless of the increase in phenylalanine levels or the use of its different forms. The finding in this study indicates that juvenile red seabream can utilize dipeptide phenylalanine as efficiently as free form without any undesirable effects on growth performance or whole-body amino acid composition.

Kim, Sung-Sam; Rahimnejad, Samad; Song, Jin-Woo; Lee, Kyeong-Jun

2012-01-01

2

Cyclopropane amino acid ester dipeptide sweeteners.  

PubMed

A series of esters of L-aspartyl-1-aminocyclopropane carboxylic acid has been prepared and their sweet tastes determined. The sweetest ester prepared was about 300 times sweeter than sucrose. An attempt to use basic conditions during preparation of the dipeptide allyl ester led to succinimide formation of the aspartyl peptide even though the beta-carboxyl group was protected by a t-butyl ester function. The X-ray structure of the propyl ester (1c) was determined and its conformation is discussed. PMID:3429129

Mapelli, C; Newton, M G; Ringold, C E; Stammer, C H

1987-10-01

3

iHyd-PseAAC: predicting hydroxyproline and hydroxylysine in proteins by incorporating dipeptide position-specific propensity into pseudo amino acid composition.  

PubMed

Post-translational modifications (PTMs) play crucial roles in various cell functions and biological processes. Protein hydroxylation is one type of PTM that usually occurs at the sites of proline and lysine. Given an uncharacterized protein sequence, which site of its Pro (or Lys) can be hydroxylated and which site cannot? This is a challenging problem, not only for in-depth understanding of the hydroxylation mechanism, but also for drug development, because protein hydroxylation is closely relevant to major diseases, such as stomach and lung cancers. With the avalanche of protein sequences generated in the post-genomic age, it is highly desired to develop computational methods to address this problem. In view of this, a new predictor called "iHyd-PseAAC" (identify hydroxylation by pseudo amino acid composition) was proposed by incorporating the dipeptide position-specific propensity into the general form of pseudo amino acid composition. It was demonstrated by rigorous cross-validation tests on stringent benchmark datasets that the new predictor is quite promising and may become a useful high throughput tool in this area. A user-friendly web-server for iHyd-PseAAC is accessible at http://app.aporc.org/iHyd-PseAAC/. Furthermore, for the convenience of the majority of experimental scientists, a step-by-step guide on how to use the web-server is given. Users can easily obtain their desired results by following these steps without the need of understanding the complicated mathematical equations presented in this paper just for its integrity. PMID:24857907

Xu, Yan; Wen, Xin; Shao, Xiao-Jian; Deng, Nai-Yang; Chou, Kuo-Chen

2014-01-01

4

iHyd-PseAAC: Predicting Hydroxyproline and Hydroxylysine in Proteins by Incorporating Dipeptide Position-Specific Propensity into Pseudo Amino Acid Composition  

PubMed Central

Post-translational modifications (PTMs) play crucial roles in various cell functions and biological processes. Protein hydroxylation is one type of PTM that usually occurs at the sites of proline and lysine. Given an uncharacterized protein sequence, which site of its Pro (or Lys) can be hydroxylated and which site cannot? This is a challenging problem, not only for in-depth understanding of the hydroxylation mechanism, but also for drug development, because protein hydroxylation is closely relevant to major diseases, such as stomach and lung cancers. With the avalanche of protein sequences generated in the post-genomic age, it is highly desired to develop computational methods to address this problem. In view of this, a new predictor called “iHyd-PseAAC” (identify hydroxylation by pseudo amino acid composition) was proposed by incorporating the dipeptide position-specific propensity into the general form of pseudo amino acid composition. It was demonstrated by rigorous cross-validation tests on stringent benchmark datasets that the new predictor is quite promising and may become a useful high throughput tool in this area. A user-friendly web-server for iHyd-PseAAC is accessible at http://app.aporc.org/iHyd-PseAAC/. Furthermore, for the convenience of the majority of experimental scientists, a step-by-step guide on how to use the web-server is given. Users can easily obtain their desired results by following these steps without the need of understanding the complicated mathematical equations presented in this paper just for its integrity.

Xu, Yan; Wen, Xin; Shao, Xiao-Jian; Deng, Nai-Yang; Chou, Kuo-Chen

2014-01-01

5

Current topics in the biotechnological production of essential amino acids, functional amino acids, and dipeptides.  

PubMed

Amino acids play important roles in both human and animal nutrition and in the maintenance of health. Here, amino acids are classified into three groups: first, essential amino acids, which are essential to nutrition; second, functional amino acids, recently found to be important in the promotion of physiological functions; and third, dipeptides, which are used to resolve problematic features of specific free amino acids, such as their instability or insolubility. This review focusses on recent researches concerning the microbial production of essential amino acids (lysine and methionine), functional amino acids (histidine and ornithine), and a dipeptide (L-alanyl-L-glutamine). PMID:24679256

Mitsuhashi, Satoshi

2014-04-01

6

Diketopiperazine Formation during Investigations of Amino Acid Racemization in Dipeptides  

Microsoft Academic Search

The formation of diketopiperazines from the dipeptides isoleucylglycine and glycylisoleucine was investigated at 132circC over the pH range ~ 2 to 10. At pH 6.2, ~ 50 percent of the original dipeptides were converted to the diketopiperazines during the heating experiments. Hydrolysis of the diketopiperazines can yield either the original dipetide or an inverted dipeptide product. The isoleucine in the

Spencer Steinberg; Jeffrey L. Bada

1981-01-01

7

[Synthesis and biological activity of new glycyrrhizic acid conjugates with amino acids and dipeptides].  

PubMed

New glycyrrhizic acid (GA) conjugates were synthesized with the use of tert-butyl esters of amino acids or benzyl esters of dipeptides; they contained two residues of L-amino acids (Met, Phe, Pro, and Ile or dipeptides Gly-Leu and Gly-Phe). Activation of GA carboxy groups was carried out with the help of N-hydroxysuccinimide, N,N'-dicyclohexylcarbodiimide, or N-hydroxybenzotriazole with dicyclohexylcarbodiimide. A proline-containing GA derivative is a low-toxic substance; it raises the level of agglutinins by 3.7 times in the blood of mice and 3 times that of hemolysins compared with the control. Dipeptide GA derivatives possess an expressed anti-HIV-1 activity in cultures of MT-4 cells and are 90-70 times less cytotoxic than azidothymidine. The selectivity index of the compounds exceeds those of GA by 110 and 34 times, respectively. PMID:19928060

Baltina, L A; Kondratenko, R M; Baltina, L A; Baschenko, N Zh; Pliasunova, O A

2009-01-01

8

N-( p-Ethynylbenzoyl) derivatives of amino acid and dipeptide methyl esters – Synthesis and structural study  

Microsoft Academic Search

A series of N-(p-ethynylbenzoyl) derivatives (1–4) of the amino acids glycine and l-alanine as well as the dipeptides glycylglycine and l-alanylglycine has been synthesized via a two-step reaction sequence including the reaction of an appropriate N-(p-bromobenzoyl) precursor with trimethylsilylacetylene followed by deprotection of the trimethylsilyl protecting group, respectively. X-ray crystal structures of the amino acid and dipeptide methyl esters 1–4

Frank Eißmann; Edwin Weber

2011-01-01

9

Absorption of glucose, amino acids, and dipeptides by the intestines of Atlantic salmon (Salmo salar L.)  

Microsoft Academic Search

Rates of glucose, amino acid and dipeptide absorption by the intestine of Atlantic salmon (Salmo salar L.) were measured in vitro at 10 °C as functions of concentration and region using intact tissues (everted sleeve method). Salmon (weight range 300–1300 g) fed a commercial, extruded salmon feed, were kept at 12–13 °C in freshwater. Maximum rates (Vmax) of glucose and dipeptide transport were low

A. M. Bakke-McKellep; S. Nordrum; Å Krogdahl; R. K. Buddington

2000-01-01

10

The Synthesis of a Dipeptide from its Component Amino Acids: Protecting Groups in the Elementary Organic Laboratory.  

ERIC Educational Resources Information Center

A simple, three-step procedure for synthesizing a dipeptide from its component amino acids is described. The dipeptide synthesized uses inexpensive amino acids having hydrocarbon side-chains and can be observed in E/Z forms by nuclear magnetic resonance spectroscopy. Each step in the synthesis produces white crystalline products using standard…

Young, Paul E.; Campbell, Andrew

1982-01-01

11

Populations of the three major backbone conformations in 19 amino acid dipeptides  

PubMed Central

The amide III region of the peptide infrared and Raman spectra has been used to determine the relative populations of the three major backbone conformations (PII, ?, and ?R) in 19 amino acid dipeptides. The results provide a benchmark for force field or other methods of predicting backbone conformations in flexible peptides. There are three resolvable backbone bands in the amide III region. The major population is either PII or ? for all dipeptides except Gly, whereas the ?R population is measurable but always minor (? 10%) for 18 dipeptides. (The Gly ?,? map is complex and so is the interpretation of the amide III bands of Gly.) There are substantial differences in the relative ? and PII populations among the 19 dipeptides. The band frequencies have been assigned as PII, 1,317–1,306 cm-1; ?R, 1,304–1,294 cm-1; and ?, 1,294–1,270 cm-1. The three bands were measured by both attenuated total reflection spectroscopy and by Raman spectroscopy. Consistent results, both for band frequency and relative population, were obtained by both spectroscopic methods. The ? and PII bands were assigned from the dependence of the 3J(HN,H?) coupling constant (known for all 19 dipeptides) on the relative ? population. The PII band assignment agrees with one made earlier from Raman optical activity data. The temperature dependences of the relative ? and PII populations fit the standard model with Boltzmann-weighted energies for alanine and leucine between 30 and 60?°C.

Grdadolnik, Joze; Mohacek-Grosev, Vlasta; Baldwin, Robert L.; Avbelj, Franc

2011-01-01

12

Reactions of An Aromatic ?,?-Biradical with Amino Acids and Dipeptides in the Gas Phase  

PubMed Central

Gas-phase reactivity of a positively charged aromatic ?,?-biradical (N-methyl-6,8-didehydroquinolinium) was examined toward six aliphatic amino acids and fifteen dipeptides by using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR) and laser-induced acoustic desorption (LIAD). While previous studies have revealed that H-atom and NH2 abstractions dominate the reactions of related monoradicals with aliphatic amino acids and small peptides, several additional, unprecedented reaction pathways were observed for the reactions of the biradical. For amino acids, these are 2H-atom abstraction, H2O abstraction, addition – CO2, addition – HCOOH and formation of a stable adduct. The biradical reacts with aliphatic dipeptides similarly as with aliphatic amino acids, but undergoes also one additional reaction pathway, addition/C-terminal amino acid elimination (addition – CO – NHCHRC). These reactions are initiated by H-atom abstraction by the biradical from the amino acid or peptide, or nucleophilic addition of an NH2 or a HO group of the amino acid or peptide at the radical site at C-6 in the biradical. Reactions of the unquenched C-8 radical site then yield the products not observed for related monoradicals. The biradical reacts with aromatic dipeptides with an aromatic ring in N-terminus (i.e., Tyr-Leu, Phe-Val and Phe-Pro) similarly as with aliphatic dipeptides. However, for those aromatic dipeptides that contain an aromatic ring in the C-terminus (i.e., Leu-Tyr and Ala-Phe), one additional pathway, addition/N-terminal amino acid elimination (addition – CO – NHCHRN), was observed. This reaction is likely initiated by radical addition of the biradical at the aromatic ring in the C-terminus. Related monoradicals add to aromatic amino acids and small peptides, which is followed by C?-C? bond cleavage, resulting in side-chain abstraction by the radical. For biradicals, with one unquenched radical site after the initial addition, the reaction ultimately results in the loss of the N-terminal amino acid. Similar to monoradicals, the C-S bond in amino acids and dipeptides was found to be especially susceptible to biradical attack.

Fu, Mingkun; Li, Sen; Archibold, Enada; Yurkovich, Michael J.; Nash, John J.; Kenttamaa, Hilkka I.

2010-01-01

13

Small intestinal absorption of amino acids and a dipeptide in pancreatic insufficiency  

Microsoft Academic Search

In this study a perfusion technique has been used to investigate in vivo jejunal absorption and transmural potential difference evoked by the neutral amino acids phenylalanine (56 or 20 mmol\\/l) and glycine (20 mmol\\/l), the dibasic amino acid lysine (56 or 5 mmol\\/l), and a dipeptide glycyl-l-phenylalanine (20 mmol\\/l) in 11 children with pancreatic insufficiency due to cystic fibrosis and

P J Milla; A Kilby; U B Rassam; R Ersser; J T Harries

1983-01-01

14

N-( p-Ethynylbenzoyl) derivatives of amino acid and dipeptide methyl esters - Synthesis and structural study  

NASA Astrophysics Data System (ADS)

A series of N-( p-ethynylbenzoyl) derivatives ( 1-4) of the amino acids glycine and L-alanine as well as the dipeptides glycylglycine and L-alanylglycine has been synthesized via a two-step reaction sequence including the reaction of an appropriate N-( p-bromobenzoyl) precursor with trimethylsilylacetylene followed by deprotection of the trimethylsilyl protecting group, respectively. X-ray crystal structures of the amino acid and dipeptide methyl esters 1-4 are reported. The amide and peptide bonds within each molecular structure are planar and adopt the trans-configuration. The packing structures are governed by N sbnd H⋯O interactions leading to the formation of characteristic strand motifs. Further stabilization results from weaker C sbnd H⋯O and C sbnd H⋯? contacts.

Eißmann, Frank; Weber, Edwin

2011-11-01

15

Cyclic dipeptides from lactic acid bacteria inhibit proliferation of the influenza A virus.  

PubMed

We isolated Lactobacillus plantarum LBP-K10 from the traditional Korean fermented food kimchi. When organic acids were removed, the culture filtrate of this isolate showed high antiviral activity (measured using a plaque-forming assay) against the influenza A (H3N2) virus. Two fractions that were active against influenza A virus were purified from the culture filtrate using a C18 column with high-performance liquid chromatography. These active fractions were crystallized and identified to be the cyclic dipeptides cis-cyclo (L-Leu-L-Pro) and cis-cyclo(L-Phe-L-Pro) using gas chromatography-mass spectrometry; this identification was confirmed by X-ray crystallography. These cyclic dipeptides were identified in the culture filtrate of other lactic acid bacteria, including Lactobacillus spp., Leuconostoc spp., Weissella spp., and Lactococcus lactis. PMID:24385362

Kwak, Min-Kyu; Liu, Rui; Kwon, Jun-Oh; Kim, Min-Kyu; Kim, Andrew HyoungJin; Kang, Sa-Ouk

2013-12-01

16

Synthesis and Antibacterial Activity of Amino Acid and Dipeptide Prodrugs of IMB-070593, a Fluoroquinolone Candidate.  

PubMed

A series of amino acid and dipeptide prodrugs of IMB-070593, a fluoroquinolone candidate discovered in our lab, were synthesized and evaluated for their water solubility and then antibacterial activity. Our results reveal that four amino acid prodrugs 4a,b,e,f and two dipeptide prodrugs 4k,l have much greater solubility (>85 mg/mL) than IMB-070593 mesylate (22.5 mg/mL). Compounds 4a and 4k show good in vivo efficacy against MSSA 12-1 (p.o./i.v., 5.32-7.68 mg/kg) and S. pneumoniae12-10 (p.o., 18.39-23.13 mg/kg) which is 1.19-1.50 fold more active than the parent drug. PMID:24858269

Zhang, Tingting; Wu, Jinwei; Chen, Shihong; Liu, Kaixiang; Lin, Yabin; Guo, Huiyuan; Liu, Mingliang

2014-01-01

17

Inhibition of dipeptidyl peptidase IV and xanthine oxidase by amino acids and dipeptides.  

PubMed

Xanthine oxidase (XO) and dipeptidyl peptidase IV (DPP-IV) inhibition by amino acids and dipeptides was studied. Trp and Trp-containing dipeptides (Arg-Trp, Trp-Val, Val-Trp, Lys-Trp and Ile-Trp) inhibited XO. Three amino acids (Met, Leu and Trp) and eight dipeptides (Phe-Leu, Trp-Val, His-Leu, Glu-Lys, Ala-Leu, Val-Ala, Ser-Leu and Gly-Leu) inhibited DPP-IV. Trp and Trp-Val were multifunctional inhibitors of XO and DPP-IV. Lineweaver and Burk analysis showed that Trp was a non-competitive inhibitor of XO and a competitive inhibitor of DPP-IV. Molecular docking with Autodock Vina was used to better understand the interaction of the peptides with the active site of the enzyme. Because of the non-competitive inhibition observed, docking of Trp-Val to the secondary binding sites of XO and DPP-IV is required. Trp-Val was predicted to be intestinally neutral (between 25% and 75% peptide remaining after 60 min simulated intestinal digestion). These results are of significance for the reduction of reactive oxygen species (ROS) and the increase of the half-life of incretins by food-derived peptides. PMID:23768405

Nongonierma, Alice B; Mooney, Catherine; Shields, Denis C; Fitzgerald, Richard J

2013-11-01

18

Some Novel Sulfanilyl Amino Acids and Dipeptides Derivatives  

Microsoft Academic Search

3-(N-phenylcarboxamido)-coumarin 1 reacted with chlorosulfonic acid to give the corresponding sulfaniyl chloride 2. However, isonicotinic acid anilide 14, and nicotinic acid anilide 33, reacted with chlorosulfonic acid in a 1:6 molar ratio, only for conversion into sulfanilyl chlorides 15 and 34. Treatment with nucleophilic reagents afforded amino acid derivatives 3–6, 16–20, and 35–37. Some of the corresponding methyl esters 7–9,

Ragab A. El-Sayed

2007-01-01

19

Photochemical reaction of 2-(3-benzoylphenyl)propionic acid (ketoprofen) with basic amino acids and dipeptides.  

PubMed

Photoreaction of 2-(3-benzoylphenyl)propionic acid (ketoprofen, KP) with basic amino acids (histidine, lysine, and arginine) and dipeptides (carnosine and anserine) including a histidine moiety in phosphate buffer solution (pH 7.4) has been investigated with transient absorption spectroscopy. With UV irradiation KP(-) gave rise to a carbanion through a decarboxylation reaction, and the carbanion easily abstracted a proton from the surrounding molecule to yield a 3-ethylbenzophenone ketyl biradical (EBPH). The dipeptides as well as the basic amino acids were found to accelerate the proton transfer reaction whereas alanine and glycine had no effect on the reaction, revealing that these amino acids having a protonated side chain act as a proton donor. The formation quantum yield of EBPH was estimated to be fairly large by means of an actinometrical method with benzophenone, and the bimolecular reaction rate constant for the proton transfer between the carbanion and the protonated basic amino acids or the protonated dipeptides was successfully determined. It has become apparent that the bimolecular reaction rate constant for the proton transfer depended on the acid dissociation constant for the side chain of the amino acids for the first time. This reaction mechanism was interpreted by difference of the heat of reaction for each basic amino acid based on the thermodynamical consideration. These results strongly suggest that the side chain of the basic amino acid residue in protein should play an important role for photochemistry of KP in vivo. PMID:23879666

Suzuki, Tadashi; Shinoda, Mio; Osanai, Yohei; Isozaki, Tasuku

2013-08-22

20

Reactions of an aromatic ?,?-biradical with amino acids and dipeptides in the gas phase  

Microsoft Academic Search

Gas-phase reactivity of a positively charged aromatic ?,?-biradical (N-methyl-6,8-didehydroquinolinium) was examined toward six aliphatic amino acids and 15 dipeptides by using Fourier transform\\u000a ion cyclotron resonance mass spectrometry (FT-ICR) and laser-induced acoustic desorption (LIAD). While previous studies have\\u000a revealed that H-atom and NH2 abstractions dominate the reactions of related monoradicals with aliphatic amino acids and small peptides, several additional,\\u000a unprecedented

Mingkun Fu; Sen Li; Enada Archibold; Michael J. Yurkovich; John J. Nash; Hilkka I. Kenttämaa

2010-01-01

21

A concept of dietary dipeptides: a step to resolve the problem of amino acid availability in the early life of vertebrates  

Microsoft Academic Search

The premise that a dietary dipeptide approach will improve the understanding of amino acid utilization in the fastest-growing vertebrate, the teleost fish, was tested by examining the muscle free amino acid (FAA) pool and enzyme activities, in concert with growth response, when dietary amino acids were provided in free, dipeptide or protein molecular forms. We present the first evidence in

Konrad Dabrowski; Bendik F. Terjesen; Yongfang Zhang; James M. Phang; Kyeong-Jun Lee

2005-01-01

22

Phenylalanine-containing cyclic dipeptides--the lowest molecular weight hydrogelators based on unmodified proteinogenic amino acids.  

PubMed

Cyclic dipeptides (diketopiperazines - DKPs) that are based on the proteinogenic amino acid phenylalanine in combination with serine, cysteine, glutamate, histidine and lysine are described as simple and remarkable low molecular weight hydrogelators. Blends of selected DKPs show remarkable pH-dependent properties and can be applied as easy to tune materials in drug delivery. PMID:23884374

Kleinsmann, Alexander J; Nachtsheim, Boris J

2013-09-14

23

Application of protein N-terminal amidase in enzymatic synthesis of dipeptides containing acidic amino acids specifically at the N-terminus.  

PubMed

Dipeptides exhibit unique physiological functions and physical properties, e.g., l-aspartyl-l-phenylalanine-methyl ester (Asp-Phe-OMe, aspartame) as an artificial sweetener, and functional studies of peptides have been carried out in various fields. Therefore, to establish a manufacturing process for the useful dipeptides, we investigated its enzymatic synthesis by utilizing an l-amino acid ligase (Lal), which catalyzes dipeptide synthesis in an ATP-dependent manner. Many Lals were obtained, but the Lals recognizing acidic amino acids as N-terminal substrates have not been identified. To increase the variety of dipeptides that are enzymatically synthesized, we proposed a two-step synthesis: Asn-Xaa and Gln-Xaa (Asn, l-asparagine; Gln, l-glutamine; and Xaa, arbitrary amino acids) synthesized by Lals were continuously deamidated by a novel amidase, yielding Asp-Xaa and Glu-Xaa (Asp, l-aspartic acid; and Glu, l-glutamic acid). We searched for amidases that specifically deamidate the N-terminus of Asn or Gln in dipeptides since none have been previously reported. We focused on the protein N-terminal amidase from Saccharomyces cerevisiae (NTA1), and assayed its activity toward dipeptides. Our findings showed that NTA1 deamidated l-asparaginyl-l-valine (Asn-Val) and l-glutaminyl-glycine (Gln-Gly), but did not deamidate l-valyl-l-asparagine and l-alanyl-l-glutamine, suggesting that this deamidation activity is N-terminus specific. The specific activity toward Asn-Val and Gln-Gly were 190 ± 30 nmol min(-1) mg(-1)·protein and 136 ± 6 nmol min(-1) mg(-1)·protein. Additionally, we examined some characteristics of NTA1. Acidic dipeptide synthesis was examined by a combination of Lals and NTA1, resulting in the synthesis of 12 kinds of Asp-Xaa, including Asp-Phe, a precursor of aspartame, and 11 kinds of Glu-Xaa. PMID:23218487

Arai, Toshinobu; Noguchi, Atsushi; Takano, Eriko; Kino, Kuniki

2013-04-01

24

D-Amino acid dipeptide production utilizing D-alanine-D-alanine ligases with novel substrate specificity.  

PubMed

D-Alanine-D-alanine ligase (Ddl) is an important enzyme in the synthesis of bacterial peptidoglycan. The genes encoding Ddls from Escherichia coli K12 (EcDdlB), Oceanobacillus iheyensis JCM 11309 (OiDdl), Synechocystis sp. PCC 6803 (SsDdl) and Thermotoga maritima ATCC 43589 (TmDdl), the genomic DNA sequences of which have been determined, were cloned and the substrate specificities of these recombinant Ddls were investigated. Although OiDdl had a high substrate specificity for D-alanine; EcDdlB, SsDdl and TmDdl showed broad substrate specificities for D-serine, D-threonine, D-cysteine and glycine, in addition to D-alanine. Four D-amino acid dipeptides were produced using EcDdlB, and D-amino acid homo-dipeptides were successfully produced at high yields except for D-threonyl-D-threonine. PMID:16233841

Sato, Masaru; Kirimura, Kohtaro; Kino, Kuniki

2005-06-01

25

Lipoteichoic acid and muramyl dipeptide synergistically induce maturation of human dendritic cells and concurrent expression of proinflammatory cytokines  

Microsoft Academic Search

Maturation is an important process by which dendritic cells (DC) develop the potent anti- gen-presentation capacity necessary for efficient activation of adaptive immunity. Here, we have investigated the ability of lipoteichoic acid (LTA) and muramyl dipeptide (MDP; the minimal struc- tural unit of peptidoglycan with immunostimulating activity) to induce maturation of human immature DC (iDC), derived from peripheral blood CD14-

Hye Jin Kim; Jae Seung Yang; Sang Su Woo; Sun Kyung Kim; Cheol-Heui Yun; Kack Kyun Kim; Seung Hyun Han

2007-01-01

26

Synthesis of functional dipeptide carnosine from nonprotected amino acids using carnosinase-displaying yeast cells.  

PubMed

Carnosine (beta-alanyl-L-histidine) is one of the bioactive dipeptides and has antioxidant, antiglycation, and cytoplasmic buffering properties. In this study, to synthesize carnosine from nonprotected amino acids as substrates, we cloned the carnosinase (CN1) gene and constructed a whole-cell biocatalyst displaying CN1 on the yeast cell surface with alpha-agglutinin as the anchor protein. The display of CN1 was confirmed by immunofluorescent labeling, and CN1-displaying yeast cells showed hydrolytic activity for carnosine. When carnosine was synthesized by the reverse reaction of CN1, organic solvents were added to the reaction mixture to reduce the water content. The CN1-displaying yeast cells were lyophilized and examined for organic solvent tolerance. Results showed that the CN1-displaying yeast cells retained their original hydrolytic activity in hydrophobic organic solvents. In the hydrophobic organic solvents and hydrophobic ionic liquids, the CN1-displaying yeast cells catalyzed carnosine synthesis, and carnosine was synthesized from nonprotected amino acids in only one step. The results of this research suggest that the whole-cell biocatalyst displaying CN1 on the yeast cell surface can be used to synthesize carnosine with ease and convenience. PMID:20082075

Inaba, Chiaki; Higuchi, Shinsuke; Morisaka, Hironobu; Kuroda, Kouichi; Ueda, Mitsuyoshi

2010-05-01

27

A concept of dietary dipeptides: a step to resolve the problem of amino acid availability in the early life of vertebrates.  

PubMed

The premise that a dietary dipeptide approach will improve the understanding of amino acid utilization in the fastest-growing vertebrate, the teleost fish, was tested by examining the muscle free amino acid (FAA) pool and enzyme activities, in concert with growth response, when dietary amino acids were provided in free, dipeptide or protein molecular forms. We present the first evidence in fish that, in response to a synthetic dipeptide diet, muscle FAA varies as a result of both growth rate and amino acid availability of specific peptides. We demonstrate significantly diminished muscle indispensable FAA (3-10-fold) in rainbow trout alevins fed a dipeptide-based diet compared with a protein-based diet. The dipeptide-based diet did not contain proline, resulting in 10-27-fold less muscle free proline and hydroxyproline in alevins. The response of alevins fed FAA-based or peptide-based diets can be indicative of collagen turnover (Hyp/Pro ratio) and showed significant differences between dietary treatments. Pyrroline-5-carboxylate (P5C) reductase activity was detected, suggesting that P5C may ameliorate proline deficiency, but synthesis from glutamate could not maintain free proline levels in muscle. This finding will provide an impetus to test whether proline is conditionally indispensable in young fish, as in mammals and birds. This study shows that amino acids given entirely as dipeptides can sustain fish growth, result in muscle FAA and enzyme responses in line with dietary levels and identify growth-limiting amino acids. The understanding of these factors necessitates a diet formulation that will improve the accuracy of determining amino acid requirements in the early life stages of vertebrates. PMID:16043593

Dabrowski, Konrad; Terjesen, Bendik F; Zhang, Yongfang; Phang, James M; Lee, Kyeong-Jun

2005-08-01

28

Cyclic dipeptides from lactic acid bacteria inhibit the proliferation of pathogenic fungi.  

PubMed

Lactobacillus plantarum LBP-K10 was identified to be the most potent antifungal strain from Korean traditional fermented vegetables. The culture filtrate of this strain showed remarkable antifungal activity against Ganoderma boninense. Five fractions from the culture filtrate were observed to have an inhibitory effect against G. boninense. Also, the electron ionization and chemical ionization indicated that these compounds might be cyclic dipeptides. Of the five active fractions, two fractions showed the most significant anti-Ganoderma activity, and one of these fractions inhibited the growth of Candida albicans. These compounds were identified to be cis-cyclo(L-Val-L-Pro) and cis-cyclo(L-Phe-L-Pro), as confirmed by X-ray crystallography. PMID:24390839

Kwak, Min-Kyu; Liu, Rui; Kim, Min-Kyu; Moon, Dohyun; Kim, Andrew Hyoungjin; Song, Sung-Hyun; Kang, Sa-Ouk

2014-01-01

29

Synthesis and application of dipeptides; current status and perspectives  

Microsoft Academic Search

The functions and applications of l-?-dipeptides (dipeptides) have been poorly studied compared with proteins or amino acids. Only a few dipeptides, such as\\u000a aspartame (l-aspartyl-l-phenylalanine methyl ester) and l-alanyl-l-glutamine (Ala-Gln), are commercially used. This can be attributed to the lack of an efficient process for dipeptide production\\u000a though various chemical or chemoenzymatic method have been reported. Recently, however, novel methods

Makoto Yagasaki; Shin-ichi Hashimoto

2008-01-01

30

Microscale Synthesis and Analysis of a Dipeptide.  

ERIC Educational Resources Information Center

Described is a microscale chemistry laboratory in which a dipeptide is synthesized from its component amino acids and analyzed using chiral-phase thin-layer chromatography. Experimental procedures, and materials are discussed. Twelve references are listed. (CW)

Blatchly, Richard A.; And Others

1989-01-01

31

The Synthesis of an Amino Acid Derivative and Spectroscopic Monitoring of Dipeptide Formation.  

ERIC Educational Resources Information Center

Described are experiments to give students experience in the synthesis of peptides from amino acids and to use visible spectroscopy to measure a rate of reaction. The activities were designed for undergraduate courses. (RH)

Simmonds, Richard J.

1987-01-01

32

Utilization of dipeptide/protein based diets in larval and juvenile Koi carp--post-prandial free amino acid levels.  

PubMed

We have shown previously that diets in which the nitrogen portion is based on synthetic dipeptides (PP) resulted in weight gain by rainbow trout alevins when free amino acid (FAA) based diets did not. However, the protein-based diet used as a control in the previous study resulted in a significantly better performance of fish than peptide- or FAA based diet fed fish. Therefore, the objectives of our study were (i) to test how stomachless fish respond to peptide-based diets, (ii) to evaluate PP and protein-PP mixture diets and (iii) to examine if post-prandial response to FAA concentrations in the fish body can be used as an indicator of the availability of dietary amino acid sources. The first experiment was conducted with a 4-day old Koi carp (Cyprinus carpio) larvae and included groups fed a casein-gelatin (CG) based diet, a commercial diet and live Artemia nauplii. In the second experiment, fish fed live Artemia for 3 weeks (69 +/- 12 mg) were placed in glass aquaria in triplicate per dietary treatment. Four diets provided equivalent amounts of nitrogen in the form of a CG, a PP, a 50% PP and 50% CG (PP50) mix and as FAA. Fish were fed at 1 and 3 h intervals, and the survival and growth were monitored during the second and third weeks of experiments 1 and 2 respectively. Following the completion of feeding, juvenile carp were sampled prior to feeding and 3 h after a meal. Whole body FAA analyses were carried out. We observed marginal suitability of the CG diet for larval Koi carp, as earlier indicated in common carp. Juvenile Koi carp fed the CG diet achieved 236 +/- 19 mg, whereas PP50, PP and FAA diet fed fish grew to 140 +/- 37, 70 +/- 8 and 73 +/- 5 mg respectively. Free amino acids in the fish body, and in particular indispensable amino acids (IDAA), were excellent indicators of dietary availability. The present experiment shows that a dietary 1:1 ratio of protein to synthetic PPs results in better growth, survival and whole body IDAA concentrations in relation to FAA- and PP-based diets confirming earlier reports on the use of synthetic PP-based diets, although this diet does not match the performance of complete protein, CG-based diet. PMID:19906146

Kwasek, K; Zhang, Y; Dabrowski, K

2010-02-01

33

Dipeptide-assisted growth of uniform gallium oxohydroxide spindles  

NASA Astrophysics Data System (ADS)

The catalytic dipeptide His-Ser was used as an additive in mineralizing gallium ions to form GaOOH, a solid precursor of Ga 2O 3. This dipeptide was chosen to mimic the enzyme structure of silicatein, similar to the well-known catalytic triad of chymotrypsin. The dipeptide promoted formation of spindle-structured GaOOH under acidic conditions by behaving as a heterogeneous nucleation seed. In contrast, no well-defined, structured gallium species were produced in the absence of dipeptide. The catalytic function of the dipeptide was most pronounced at pH values in the range 3-5, which are lower than the pKa of imidazole in the His side chain. These results suggest that the catalytic role of dipeptide influences the gallium hydroxide conversion and growth. This study suggests that a designed peptide with active functionality can be further exploited to produce inorganic compounds with controlled nucleation and growth.

Lee, Inho; Kwak, Jinyoung; Haam, Seungjoo; Lee, Sang-Yup

2010-07-01

34

The amino-acid substituents of dipeptide substrates of cathepsin C can determine the rate-limiting steps of catalysis.  

PubMed

We examined the cathepsin C-catalyzed hydrolysis of dipeptide substrates of the form Yaa-Xaa-AMC, using steady-state and pre-steady-state kinetic methods. The substrates group into three kinetic profiles based upon the broad range observed for k(cat)/K(a) and k(cat) values, pre-steady-state time courses, and solvent kinetic isotope effects (sKIEs). The dipeptide substrate Gly-Arg-AMC displayed large values for k(cat)/K(a) (1.6 ± 0.09 ?M(-1) s(-1)) and k(cat) (255 ± 6 s(-1)), an inverse sKIE on k(cat)/K(a) ((D)(k(cat)/K(a)) = 0.6 ± 0.15), a modest, normal sKIE on k(cat) ((D)k(cat) = 1.6 ± 0.2), and immeasurable pre-steady-state kinetics, indicating an extremely fast pre-steady-state rate (>400 s(-1)). (Errors on fitted values are omitted in the text for clarity but may be found in Table 2.) These results conformed to a kinetic model where the acylation (k(ac)) and deacylation (k(dac)) half-reactions are very fast and similar in value. The second substrate type, Gly-Tyr-AMC and Ser-Tyr-AMC, the latter the subject of a comprehensive kinetic study (Schneck et al. (2008) Biochemistry 47, 8697-8710), were found to be less active substrates compared to Gly-Arg-AMC, with respective k(cat)/K(a) values of 0.49 ± 0.07 ?M(-1 )s(-1) and 5.3 ± 0.5 ?M(-1 )s(-1), and k(cat) values of 28 ± 1 s(-1) and 25 ± 0.5 s(-1). Solvent kinetic isotope effects for Ser-Tyr-AMC were found to be inverse for k(cat)/K(a) ((D)(k(cat)/K(a)) = 0.74 ± 0.05) and normal for k(cat) ((D)k(cat) = 2.3 ± 0.1) but unlike Gly-Arg-AMC, pre-steady-state kinetics of Gly-Tyr-AMC and Ser-Tyr-AMC were measurable and characterized by a single-exponential burst, with fast transient rates (490 s(-1) and 390 s(-1), respectively), from which it was determined that k(ac) ? k(dac) ? k(cat). The third substrate type, Gly-Ile-AMC, gave very low values of k(cat)/K(a) (0.0015 ± 0.0001 ?M(-1) s(-1)) and k(cat) (0.33 ± 0.02 s(-1)), no sKIEs, ((D)(k(cat)/K(a)) = 1.05 ± 0.5 and (D)k(cat) = 1.06 ± 0.4), and pre-steady-state kinetics exhibited a discernible, but negligible, transient phase. For this third class of substrate, kinetic modeling was consistent with a mechanism in which k(dac) > k(ac) ? k(cat), and for which an isotope-insensitive step in the acylation half-reaction is the slowest. The combined results of these studies suggested that the identity of the amino acid at the P(1) position of the substrate is the main determinant of catalysis. On the basis of these kinetic data, together with crystallographic studies of substrate analogues and molecular dynamics analysis with models of acyl-enzyme intermediates, we present a catalytic model derived from the relative rates of the acylation vs deacylation half-reactions of cathepsin C. The chemical steps of catalysis are proposed to be dependent upon the conformational freedom of the amino acid substituents for optimal alignment for thiolation (acylation) or hydrolysis (deacylation). These studies suggest ideas for inhibitor design for papain-family cysteine proteases and strategies to progress drug discovery for other classes of disease-relevant cysteine proteases. PMID:22928782

Rubach, Jon K; Cui, Guanglei; Schneck, Jessica L; Taylor, Amy N; Zhao, Baoguang; Smallwood, Angela; Nevins, Neysa; Wisnoski, David; Thrall, Sara H; Meek, Thomas D

2012-09-25

35

Dietary cyclic dipeptides, apoptosis and psychiatric disorders: A hypothesis.  

PubMed

Cyclic dipeptides from food and intestinal yeast cyclic dipeptides may play a role in causing psychiatric disorders such as schizophrenia. From cancer research, cyclic dipeptides such as cyclo (proline-phenylalanine) have been found to activate the pathways of apoptosis and to cause programmed cell death. Activation of such pathways is also thought to be important in causing the neurodevelopmental abnormalities seen in disorders such as schizophrenia and autistic disorder, and also may be important in Alzheimer's. Cyclic dipeptides are found in foods such as malt and cocoa and beer. The intestinal yeast Candida albicans also synthesizes cyclic dipeptides. These dipeptides may be activating apoptosis pathways throughout fetal development and postnatal development, leading to some of the changes seen in brain in schizophrenia and in other psychiatric disorders. These compounds should be researched further to see if they play a role in causing these brain changes. In addition, these cyclic dipeptides are considered within the larger context of research on amino acids and other cyclic dipeptides in neurotransmission and neurophysiology. A better understanding of the role of these cyclic dipeptides in psychiatric disorders could lead to strategies for prevention and treatment of these disorders. PMID:24717821

Semon, Bruce A

2014-06-01

36

Peptide transporter isoforms are discriminated by the fluorophore-conjugated dipeptides ?-Ala- and d-Ala-Lys-N-7-amino-4-methylcoumarin-3-acetic acid  

PubMed Central

Abstract Peptide transporters of the SLC15 family are classified by structure and function into PEPT1 (low?affinity/high?capacity) and PEPT2 (high?affinity/low?capacity) isoforms. Despite the differences in kinetics, both transporter isoforms are reckoned to transport essentially all possible di? and tripeptides. We here report that the fluorophore?conjugated dipeptide derivatives ??Ala?Lys?N?7?amino?4?methylcoumarin?3?acetic acid (??AK?AMCA) and d?Ala?Lys?N?7?amino?4?methylcoumarin?3?acetic acid (d?AK?AMCA) are transported by distinct PEPT isoforms in a species?specific manner. Transport of the fluorophore peptides was studied (1) in vitro after heterologous expression in Xenopus oocytes of PEPT1 and PEPT2 isoforms from different vertebrate species and of PEPT1 and PEPT2 transporters from Caenorhabditis elegans by using electrophysiological and fluorescence methods and (2) in vivo in C. elegans by using fluorescence methods. Our results indicate that both substrates are transported by the vertebrate “renal?type” and the C. elegans “intestinal?type” peptide transporter only. A systematic analysis among species finds four predicted amino acid residues along the sequence that may account for the substrate uptake differences observed between the vertebrate PEPT1/nematode PEPT2 and the vertebrate PEPT2/nematode PEPT1 subtype. This selectivity on basis of isoforms and species may be helpful in better defining the structure–function determinants of the proteins of the SLC15 family.

Kottra, Gabor; Spanier, Britta; Verri, Tiziano; Daniel, Hannelore

2013-01-01

37

Peptide transporter isoforms are discriminated by the fluorophore-conjugated dipeptides ?-Ala- and d-Ala-Lys-N-7-amino-4-methylcoumarin-3-acetic acid.  

PubMed

Peptide transporters of the SLC15 family are classified by structure and function into PEPT1 (low-affinity/high-capacity) and PEPT2 (high-affinity/low-capacity) isoforms. Despite the differences in kinetics, both transporter isoforms are reckoned to transport essentially all possible di- and tripeptides. We here report that the fluorophore-conjugated dipeptide derivatives ?-Ala-Lys-N-7-amino-4-methylcoumarin-3-acetic acid (?-AK-AMCA) and d-Ala-Lys-N-7-amino-4-methylcoumarin-3-acetic acid (d-AK-AMCA) are transported by distinct PEPT isoforms in a species-specific manner. Transport of the fluorophore peptides was studied (1) in vitro after heterologous expression in Xenopus oocytes of PEPT1 and PEPT2 isoforms from different vertebrate species and of PEPT1 and PEPT2 transporters from Caenorhabditis elegans by using electrophysiological and fluorescence methods and (2) in vivo in C. elegans by using fluorescence methods. Our results indicate that both substrates are transported by the vertebrate "renal-type" and the C. elegans "intestinal-type" peptide transporter only. A systematic analysis among species finds four predicted amino acid residues along the sequence that may account for the substrate uptake differences observed between the vertebrate PEPT1/nematode PEPT2 and the vertebrate PEPT2/nematode PEPT1 subtype. This selectivity on basis of isoforms and species may be helpful in better defining the structure-function determinants of the proteins of the SLC15 family. PMID:24744852

Kottra, Gabor; Spanier, Britta; Verri, Tiziano; Daniel, Hannelore

2013-12-01

38

Three-dimensional quantitative structure-activity relationship and comparative molecular field analysis of dipeptide hydroxamic acid Helicobacter pylori urease inhibitors.  

PubMed

A homology model of Helicobacter pylori urease was developed by using the crystal structure of urease from Klebsiella aerogenes (EC 3.5.1.5) as a template. The acetohydroxamic acid moiety was docked into the active pocket of the enzyme model, followed by relaxation of the complex by use of molecular dynamics. The resulting conformation was used as a template to construct 24 potential dipeptide hydroxamic acid inhibitors with which comparative molecular field analysis (CoMFA) was performed. The resulting model provided a cross-validation correlation coefficient (q(2)(L00)) of 0.610, a conventional r(2) value of 0.988, and an F (Fisher indication of statistical significance) value of 294.88. We were able to validate the CoMFA model by using the 50% inhibitory concentrations of six compounds that were not included in the construction of the model. A very good structural correlation was observed between the amino acids in the model urease's active pocket and the contour maps derived from the CoMFA model. This correlation, accompanied by the validation supplied by use of the CoMFA data, illustrates that the model can aid in the prediction and design of novel H. pylori urease inhibitors. PMID:12121941

Mishra, Hetal; Parrill, Abby L; Williamson, John S

2002-08-01

39

Dipeptides in nutrition and therapy: cyanophycin-derived dipeptides as natural alternatives and their biotechnological production  

Microsoft Academic Search

The numerous physiological functions of the nonessential amino acid L-aspartate, the semi-essential amino acid L-arginine,\\u000a and the essential amino acid L-lysine, made them attractive for a wide range of nutritional and\\/or therapeutic applications.\\u000a Furthermore, the administration of these amino acids as mixtures or as dipeptides for higher bioavailability is scientifically\\u000a approved, and various commercial products of these forms are already

Ahmed Sallam; Alexander Steinbüchel

2010-01-01

40

Bradykinin antagonists modified with dipeptide mimetic beta-turn inducers.  

PubMed

Bradykinin (BK) is involved in a wide variety of pathophysiological processes. Potent BK peptide antagonists can be developed introducing constrained unnatural amino acids, necessary to force the secondary structure of the molecule. In this paper, we report a structure-activity relationship study of two peptide analogues of the potent B2 antagonist HOE 140 by replacing the D-Tic-Oic dipeptide with conformationally constrained dipeptide mimetic beta-turn inducers. PMID:16504505

Alcaro, Maria C; Vinci, Valerio; D'Ursi, Anna M; Scrima, Mario; Chelli, Mario; Giuliani, Sandro; Meini, Stefania; Di Giacomo, Marcello; Colombo, Lino; Papini, Anna Maria

2006-05-01

41

Characteristics of a New Enantioselective Thermostable Dipeptidase from Brevibacillus borstelensis BCS-1 and Its Application to Synthesis of a d-Amino-Acid-Containing Dipeptide  

PubMed Central

A new thermostable dipeptidase gene was cloned from the thermophile Brevibacillus borstelensis BCS-1 by genetic complementation of the d-Glu auxotroph Escherichia coli WM335 on a plate containing d-Ala-d-Glu. Nucleotide sequence analysis revealed that the gene included an open reading frame coding for a 307-amino-acid sequence with an Mr of 35,000. The deduced amino acid sequence of the dipeptidase exhibited 52% similarity with the dipeptidase from Listeria monocytogenes. The enzyme was purified to homogeneity from recombinant E. coli WM335 harboring the dipeptidase gene from B. borstelensis BCS-1. Investigation of the enantioselectivity (E) to the P1 and P1? site of Ala-Ala revealed that the ratio of the specificity constant (kcat/Km) for l-enantioselectivity to the P1 site of Ala-Ala was 23.4 ± 2.2 [E = (kcat/Km)l,d/(kcat/Km)d,d], while the d-enantioselectivity to the P1? site of Ala-Ala was 16.4 ± 0.5 [E = (kcat/Km)l,d/(kcat/Km)l,l] at 55°C. The enzyme was stable up to 55°C, and the optimal pH and temperature were 8.5 and 65°C, respectively. The enzyme was able to hydrolyze l-Asp-d-Ala, l-Asp-d-AlaOMe, Z-d-Ala-d-AlaOBzl, and Z-l-Asp-d-AlaOBzl, yet it could not hydrolyze d-Ala-l-Asp, d-Ala-l-Ala, d-AlaNH2, and l-AlaNH2. The enzyme also exhibited ?-lactamase activity similar to that of a human renal dipeptidase. The dipeptidase successfully synthesized the precursor of the dipeptide sweetener Z-l-Asp-d-AlaOBzl.

Baek, Dae Heoun; Song, Jae Jun; Kwon, Seok-Joon; Park, Chung; Jung, Chang-Min; Sung, Moon-Hee

2004-01-01

42

Biological functions of histidine-dipeptides and metabolic syndrome.  

PubMed

The rapid increase in the prevalence of metabolic syndrome, which is associated with a state of elevated systemic oxidative stress and inflammation, is expected to cause future increases in the prevalence of diabetes and cardiovascular diseases. Oxidation of polyunsaturated fatty acids and sugars produces reactive carbonyl species, which, due to their electrophilic nature, react with the nucleophilic sites of certain amino acids. This leads to formation of protein adducts such as advanced glycoxidation/lipoxidation end products (AGEs/ALEs), resulting in cellular dysfunction. Therefore, an effective reactive carbonyl species and AGEs/ALEs sequestering agent may be able to prevent such cellular dysfunction. There is accumulating evidence that histidine containing dipeptides such as carnosine (?-alanyl-L-histidine) and anserine (?-alanyl-methyl-L-histidine) detoxify cytotoxic reactive carbonyls by forming unreactive adducts and are able to reverse glycated protein. In this review, 1) reaction mechanism of oxidative stress and certain chronic diseases, 2) interrelation between oxidative stress and inflammation, 3) effective reactive carbonyl species and AGEs/ALEs sequestering actions of histidine-dipeptides and their metabolism, 4) effects of carnosinase encoding gene on the effectiveness of histidine-dipeptides, and 5) protective effects of histidine-dipeptides against progression of metabolic syndrome are discussed. Overall, this review highlights the potential beneficial effects of histidine-dipeptides against metabolic syndrome. Randomized controlled human studies may provide essential information regarding whether histidine-dipeptides attenuate metabolic syndrome in humans. PMID:24611099

Song, Byeng Chun; Joo, Nam-Seok; Aldini, Giancarlo; Yeum, Kyung-Jin

2014-02-01

43

Inhibition of LiCl-induced conditioning of anticipatory nausea in rats following immune system stimulation: comparing the immunogens lipopolysaccharide, muramyl dipeptide, and polyinosinic: polycytidylic acid.  

PubMed

The effects of the bacterial endotoxins, lipopolysaccharide (LPS) and muramyl dipeptide (MDP; Experiment 1), and the viral mimetic, polyinosinic: polycytidylic acid (poly I:C; Experiment 2), on the acquisition of "conditioned gaping" behavior in the rodent model of LiCl-induced anticipatory nausea were examined. Experimentally naïve adult male Long-Evans rats were injected (intraperitoneal, i.p.) with either 200 ?g/kg LPS, 1.6 mg/kg MDP, or 0.9% saline (Experiment 1), or 4.0 mg/kg poly I:C or 0.9% saline (Experiment 2), 90 min prior to treatment with 127 mg/kg LiCl or saline control and immediately placed into a distinctive context for 30 min (repeated over 4 conditioning days, spaced 72 h apart). On a drug-free test day (72 h following conditioning day 4), each animal was re-exposed to the context for 10 min, and orofacial and aversive behavioral responses were video recorded and analyzed. The results showed that pre-treatment with LPS, MDP (Experiment 1), or poly I:C (Experiment 2) prior to LiCl+context conditioning significantly impaired the establishment of conditioned gaping behavior, thus blocking the acquisition of anticipatory nausea. Results varied in regards to peripheral acute-phase response sickness behaviors, with significantly reduced weight loss in LPS-treated animals, less robust weight loss in poly I:C-treated animals, and no significant reductions in body weight in MDP-treated animals. The learning impairments observed in the current study suggest that endotoxin treatment with bacterial and viral endotoxin may have stronger central effects on learning and memory behavior, relative to peripheral effects on body weight and other sickness-related responses. PMID:22342813

Cloutier, Caylen J; Rodowa, Melinda-Sue; Cross-Mellor, Shelley K; Chan, Melissa Y T; Kavaliers, Martin; Ossenkopp, Klaus-Peter

2012-05-15

44

Nucleic acid detection compositions  

DOEpatents

The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

Prudent, James R. (Madison, WI) [Madison, WI; Hall, Jeff G. (Madison, WI) [Madison, WI; Lyamichev, Victor I. (Madison, WI) [Madison, WI; Brow, Mary Ann (Madison, WI) [Madison, WI; Dahlberg, James L. (Madison, WI) [Madison, WI

2008-08-05

45

A combined simulation with ab initio MO and classical vibrational analysis on the specific interactions between thermolysin and dipeptide ligands  

NASA Astrophysics Data System (ADS)

Thermolysin (TLN) is a metalloprotease widely used for elaborating peptides of amino acid residues. Its enzyme activity is inhibited by the binding of dipeptide molecules. We here investigate specific interactions and binding free energies between TLN and two dipeptides by molecular simulations based on ab initio fragment molecular orbital and classical vibrational analysis methods. The results elucidate that binding free energies between TLN and dipeptides can explain experimentally observed inhibition of TLN activity by dipeptide binding, indicating the importance of entropic effect on the binding affinity between TLN and dipeptides.

Dedachi, Kenichi; Khan, Mahmud Tareq Hassan; Sylte, Ingebrigt; Kurita, Noriyuki

2009-09-01

46

ON THE FORMATION OF DIPEPTIDES IN INTERSTELLAR MODEL ICES  

SciTech Connect

The hypothesis of an exogenous origin and delivery of biologically important molecules to early Earth presents an alternative route to their terrestrial in situ formation. Dipeptides like Gly-Gly detected in the Murchison meteorite are considered as key molecules in prebiotic chemistry because biofunctional dipeptides present the vital link in the evolutionary transition from prebiotic amino acids to early proteins. However, the processes that could lead to the exogenous abiotic synthesis of dipeptides are unknown. Here, we report the identification of two proteinogenic dipeptides-Gly-Gly and Leu-Ala-formed via electron-irradiation of interstellar model ices followed by annealing the irradiated samples to 300 K. Our results indicate that the radiation-induced, non-enzymatic formation of proteinogenic dipeptides in interstellar ice analogs is facile. Once synthesized and incorporated into the ''building material'' of solar systems, biomolecules at least as complex as dipeptides could have been delivered to habitable planets such as early Earth by meteorites and comets, thus seeding the beginning of life as we know it.

Kaiser, R. I.; Kim, Y. S. [Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822 (United States); Stockton, A. M.; Jensen, E. C.; Mathies, R. A. [Department of Chemistry, University of California, Berkeley, CA 94720 (United States)

2013-03-10

47

Copper(II)-binding ability of stereoisomeric cis- and trans-2-aminocyclohexanecarboxylic acid-L-phenylalanine dipeptides. A combined CW/pulsed EPR and DFT study.  

PubMed

With the aim of an improved understanding of the metal-complexation properties of alicyclic ?-amino acid stereoisomers, and their peptides, the complex equilibria and modes of coordination with copper(II) of L-phenylalanine (F) derivatives of cis/trans-2-aminocyclohexanecarboxylic acid (c/tACHC), i.e. the dipeptides F-c/tACHC and c/tACHC-F, were investigated by a combination of CW and pulsed EPR methods. For the interpretation of the experimental data, DFT quantum-chemical calculations were carried out. Simulation of a pH-dependent series of room-temperature CW-EPR spectra revealed the presence of EPR-active complexes ([Cu(aqua)](2+), [CuL](+), [CuLH(-1)], [CuLH(-2)](-), and [CuL(2)H(-1)](-)), and an EPR-inactive species ([Cu(2)L(2)H(-3)](-)) in aqueous solutions for all studied cases. [CuLH](2+) was included in the equilibrium model for the c/tACHC-F-copper(II) systems, and [CuL(2)], together with two coordination isomers of [CuL(2)H(-1)](-), were also identified in the F-tACHC-copper(II) system. Comparison of the complexation properties of the diastereomeric ligand pair F-(1S,2R)-ACHC and F-(1R,2S)-ACHC did not reveal significant differences. Considerably lower formation constants were obtained for the trans than for the cis isomers for both the F-c/tACHC and the c/tACHC-F pairs in the case of [CuLH(-1)] involving tridentate coordination by the amino, the deprotonated peptide, and the carboxylate groups. A detailed structural analysis by pulsed EPR methods and DFT calculations indicated that there was no significant destabilization for the complexes of the trans isomers. The lower stability of their complexes was explained by the limitation that only the conformer with donor groups in equatorial-equatorial ring positions can bind to copper(II), whereas both equatorial-axial conformers of the cis isomers are capable of binding. From a consideration of the proton couplings obtained with X-band (1)H HYSCORE, (2)H exchange experiments, and DFT, the thermodynamically most stable cyclohexane ring conformer was assigned for all four [CuLH(-1)] complexes. For the F-cACHC case, the conformer did not match the most stable conformer of the free ligand. PMID:22225497

Nagy, Nóra V; Van Doorslaer, Sabine; Szabó-Plánka, Terézia; Van Rompaey, Senne; Hamza, Andrea; Fülöp, Ferenc; Tóth, Gábor K; Rockenbauer, Antal

2012-02-01

48

Synthesis of the host-selective phytotoxin destruxin B. Avoiding diketopiperazine formation from an N-methyl amino acid dipeptide by use of the Boc-hydrazide derivative  

Microsoft Academic Search

An efficient synthesis of the cyclic hexdepsipeptide destruxin B from its component residues is described that involves a [3+3] fragment coupling followed by cyclization via the azide method. A novel feature of the synthesis is the use of the Boc-hydrazide protecting group for the C-terminal N-methylalanine residue. This group serves both to inhibit facile diketopiperazine formation from the N-methylvalyl-N-methylalanine dipeptide

Dale E. Ward; Ryszard Lazny; M. Soledade C. Pedras

1997-01-01

49

Pseudopeptidic cages as receptors for N-protected dipeptides.  

PubMed

The molecular recognition of short peptides is a challenge in supramolecular chemistry, and the use of peptide-like cage receptors represents a promising approach. Here we report the synthesis and characterization of a diverse family of pseudopeptidic macrobicycles, as well as their binding abilities toward N-protected dipeptides using a combination of different techniques (NMR, ESI-MS, and fluorescence spectroscopy). The cage hosts were assayed for dipeptide binding using competition ESI-MS experiments as high-throughput screening to obtain general trends for the recognition phenomena. Selected hosts were additionally studied by NMR spectroscopy ((1)H NMR titration and diffusion-ordered spectroscopy experiments) in different solvents. The results unambiguously demonstrated the formation of the [cage·dipeptide] supramolecular complexes and rendered quantitative information about the strength of the interaction (Kass). The structural variables within the pseudopeptidic cage framework that produced a stronger and more selective recognition were thus identified. The cages showed a remarkable selectivity for N-protected dipeptides with an aromatic amino acid at the carboxylic terminus, which prompted us to propose a mode of binding based on polar and nonpolar noncovalent interactions. Accordingly, we faced the molecular recognition of a target dipeptide (Ac-EY-OH) mimicking a biologically relevant sequence by NMR and fluorescence spectroscopy in highly competitive media. PMID:24749998

Faggi, Enrico; Moure, Alejandra; Bolte, Michael; Vicent, Cristian; Luis, Santiago V; Alfonso, Ignacio

2014-05-16

50

Synthesis and Conformational Analysis of Bicyclic Extended Dipeptide Surrogates  

PubMed Central

Regio- and diastereoselective reactions of a homoproline enolate enable the synthesis of novel extended dipeptide surrogates. Bicyclic carbamate 9 and fused ?-lactam scaffold 11 were prepared from L-pyroglutamic acid via substrate-controlled electrophilic azidation. Synthesis of orthogonally-protected hexahydropyrrolizine, hexahydropyrrolizinone, and hexahydropyrroloazepinone dipeptide surrogates relied on allylation of proline derivative 5, followed by Curtius rearrangement to introduce the N-terminal carbamate group. A total of six azabicycloalkane derivatives were evaluated for conformational mimicry of extended dipeptides by a combination of x-ray diffraction and molecular modeling. Analysis of putative backbone dihedral angles and N- to C-terminal dipeptide distances indicate that compounds (??S)-14b and 21 approximate the conformation of dipeptides found in ?-sheets, while tripeptide mimic 28 is also highly extended in the solid state. Structural data suggest that ring size and relative stereochemistry have a profound effect on the ability of these scaffolds to act as ?-strand mimetics and should inform the design of related conformational probes.

Ranatunga, Sujeewa; Liyanage, Wathsala; Del Valle, Juan R.

2010-01-01

51

A tandem mass spectrometric investigation of N-(3-ferrocenyl-2-naphthoyl) dipeptide ethyl esters and N-(6-ferrocenyl-2-naphthoyl) dipeptide ethyl esters.  

PubMed

N-(3-Ferrocenyl-2-naphthoyl) dipeptide ethyl esters 1-4 and N-(6-ferrocenyl-2-naphthoyl) dipeptide ethyl esters 5-8 were prepared by coupling either 3-ferrocenylnaphthalene-2-carboxylic acid or 6-ferrocenylnaphthalene-2-carboxylic acid to the dipeptide ethyl esters GlyGly(OEt) (1, 5), AlaGly(OEt) (2, 6), GlyPhe(OEt) (3, 7) and GlyLeu(OEt) (4, 8), using the standard N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride, 1-hydroxybenzotriazole protocol. Electrospray ionization mass spectrometry (ESI-MS) and laser desorption ionization mass spectrometry (LDI-MS) were employed in conjunction with tandem mass spectrometry in the analysis of N-(3-ferrocenyl-2-naphthoyl) dipeptide ethyl esters 1-4 and N-(6-ferrocenyl-2-naphthoyl) dipeptide ethyl esters 5-8. Radical cations, [M](+•) and [M + H](+) species were both observed in the mass spectra. Intense sodium [M + Na](+) and potassium [M + K](+) adducts were also present. An important diagnostic ion at m/z [M-65](+) was observed in both the MS and MS/MS spectra of the N-(3-ferrocenyl-2-naphthoyl) dipeptide derivatives. Sequence-specific ions were generally not observed in the MS/MS spectra of the N-(3-ferrocenyl-2-naphthoyl) series due to formation of the diagnostic [M-65](+) ion. Sequence-specific ions were observed in the MS/MS spectra of the N-(6-ferrocenyl-2-naphthoyl) dipeptide esters with charge retention on the derivatized N-terminal of the dipeptide. Both series of compounds could be successfully analyzed by MALDI without the use of a matrix (LDI). PMID:21913269

Rai, Dilip K; Mooney, Áine; Kenny, Peter T M

2011-10-15

52

Gelled acidic well treating composition and process  

SciTech Connect

Gelled acidic compositions suitable for either matrix-acidizing or fracture-acidizing of subterranean formations comprising water , a water-dispersible polymer selected from cellulose ethers and polymers of acrylamides, an acid, an aldehyde, and a phenolic compound capable of causing gelation of an aqueous dispersion of the polymer, acid, aldehyde, and phenolic compound are provided. In another embodiment, guar gum, polyvinylpyrrolidone and biopolysaccharides can also be used as the polymeric component in said compositions.

Swanson, B.L.

1981-01-13

53

Frequency of dipeptides and antidipeptides  

PubMed Central

Although it is reasonable to expect that the frequency of a generic dipeptide XY in proteins is the same of its counterpart YX, on the basis of an accurate statistical analysis of a large number of protein sequences, it appears that some dipeptides XY are considerably more frequent than their mirror images YX, referred to as antidipeptides. Given that it has been verified that this unexpected anisotropic frequency of occurrence is unbiased by the type of protein sequences that are analyzed, it is possible to conclude that this is a genuine phenomenon. Nevertheless, it was impossible to find the mechanism underlying this unexpected phenomenon, which does not seem to be related to diverse conformational propensities, to the different conformational flexibility of the peptide/antidipeptide pair, to dissimilar accessibility to the solvent or to gene random mutations.

Carugo, Oliviero

2013-01-01

54

Optimization of dipeptide–protein mixtures in experimental diet formulations for rainbow trout ( Oncorhynchus mykiss) alevins  

Microsoft Academic Search

It has previously been shown that diets in which the amino acid portion is based on synthetic dipeptides result in positive growth of rainbow trout alevins. However, the protein-based diets used as a control performed significantly better. One objective of the present study was to identify a protein–dipeptide mixture ratio that results in comparable growth to a protein-based control, in

Bendik F. Terjesen; Kyeong-Jun Lee; Yongfang Zhang; Mark Failla; Konrad Dabrowski

2006-01-01

55

[Interstrain differences in the content of excitatory and inhibitory amino acids in the brain of DBA/2J, Balb/c and C57BL/6 mice: characteristics of the effect of a dipeptide antipsychotic drug dilept].  

PubMed

We have performed a comparative study of the content of glutamate (Glu), aspartate (Asp), taurine (Tau), glycine (Gly) and gamma-amino-butyric acid (GABA) in the cortex, hippocampus, and striatum of the DBA/2J, Balb/c and C57BL/6 mice brain. The levels of Glu, Tau and GABA in DBA/2J hippocampus was lower than those in other experimental strains. These findings are consistent with published data on the specific neurophysiological properties of DBA/2J (neuroleptic sensitive prepulse inhibition, deficit), thus allowing this strain to be used in modeling schizophrenia. Taking into account these facts, in the next step we investigated the effects of dilept, the new neurotensine-derived dipeptide with antipsychotic activity (GZR-123, methyl ester of N-caproyl-L-prolyltyrosine), on the content of neurotransmitter acids in DBA/2J mice brain structures. In a dose of 0.8 mg/kg (i.p.) dilept induced a statistically significant increase in the levels of Glu, Tau and GABA in striatum of DBA/2J, as well as insignificant increase in the levels of these amino acids in the cortex. These effects are quite similar to those described for the parent peptide neurotensine, in case of its intracerebral administration. The results of our study prove the necessity of the further development of dilept as a potential antipsychotic drug. PMID:18819433

Shubenina, E B; Kudrin, V S; Klodt, P M; Pokrovski?, A A; Gudasheva, T A; Voronina, T A; Ostrovskaia, R U

2008-01-01

56

Bradykinin antagonists modified with dipeptide mimetic ?-turn inducers  

Microsoft Academic Search

Bradykinin (BK) is involved in a wide variety of pathophysiological processes. Potent BK peptide antagonists can be developed introducing constrained unnatural amino acids, necessary to force the secondary structure of the molecule. In this paper, we report a structure–activity relationship study of two peptide analogues of the potent B2 antagonist HOE 140 by replacing the D-Tic-Oic dipeptide with conformationally constrained

Maria C. Alcaro; Valerio Vinci; Anna M. D’Ursi; Mario Scrima; Mario Chelli; Sandro Giuliani; Stefania Meini; Marcello Di Giacomo; Lino Colombo; Anna Maria Papini

2006-01-01

57

Synthesis and properties of N ? -lauroyl-L-arginine dipeptides from collagen-lauroyl-L-arginine dipeptides from collagen  

Microsoft Academic Search

In order to obtain protein-based amphoteric surfactants with antimicrobial properties, N\\u000a ?\\u000a -lauroyl arginine dipeptides have been prepared by condensation between N\\u000a ?\\u000a -lauroyl arginine and amino acids which come from a collagen hydrolysate. Some surfactant properties and the minimum inhibitory\\u000a concentration against Gram positive and Gram negative bacteria have been evaluated. All types of compounds presented a surfactant-like\\u000a behavior.

J. Molineroa; M. R. Juliao; P. Erraa; M. Roberlb; M. R. Infante

1988-01-01

58

Composition for nucleic acid sequencing  

DOEpatents

The present invention is directed to a method of sequencing a target nucleic acid molecule having a plurality of bases. In its principle, the temporal order of base additions during the polymerization reaction is measured on a molecule of nucleic acid, i.e. the activity of a nucleic acid polymerizing enzyme on the template nucleic acid molecule to be sequenced is followed in real time. The sequence is deduced by identifying which base is being incorporated into the growing complementary strand of the target nucleic acid by the catalytic activity of the nucleic acid polymerizing enzyme at each step in the sequence of base additions. A polymerase on the target nucleic acid molecule complex is provided in a position suitable to move along the target nucleic acid molecule and extend the oligonucleotide primer at an active site. A plurality of labelled types of nucleotide analogs are provided proximate to the active site, with each distinguishable type of nucleotide analog being complementary to a different nucleotide in the target nucleic acid sequence. The growing nucleic acid strand is extended by using the polymerase to add a nucleotide analog to the nucleic acid strand at the active site, where the nucleotide analog being added is complementary to the nucleotide of the target nucleic acid at the active site. The nucleotide analog added to the oligonucleotide primer as a result of the polymerizing step is identified. The steps of providing labelled nucleotide analogs, polymerizing the growing nucleic acid strand, and identifying the added nucleotide analog are repeated so that the nucleic acid strand is further extended and the sequence of the target nucleic acid is determined.

Korlach, Jonas (Ithaca, NY) [Ithaca, NY; Webb, Watt W. (Ithaca, NY) [Ithaca, NY; Levene, Michael (Ithaca, NY) [Ithaca, NY; Turner, Stephen (Ithaca, NY) [Ithaca, NY; Craighead, Harold G. (Ithaca, NY) [Ithaca, NY; Foquet, Mathieu (Ithaca, NY) [Ithaca, NY

2008-08-26

59

Gasoline composition containing acid anhydrides  

SciTech Connect

A composition is described comprising a major amount of a liquid hydrocarbon base fuel and an anti-knock enhancing amount of a compound selected from the group consisting of pivalic anhydride and acetic anhydride. The composition is essentially free of organo-lead compounds.

Jessup, P.J.; Brass, S.G.; Croudace, M.C.

1987-03-03

60

Aqueous highly acidic hard surface cleaning compositions  

US Patent & Trademark Office Database

Provided are highly aqueous liquid acidic hard surface cleaning compositions having a pH of about 3 or less which comprise: an acid constituent, preferably comprising a ternary acid system consisting formic acid, sulfamic acid and oxalic acid, optionally at least one or more further co-acids; at least one nonionic surfactant based on monobranched alkoxylated C10/C11-fatty alcohols; an organic solvent constituent which comprises at least one glycol ether solvent, preferably a glycol ether solvent which desirably mitigates or masks malodors of the acid constituent, especially when the acid constituent comprises formic acid; optionally a cosurfactant constituent, including one or more nonionic, cationic, amphoteric or zwitterionic surfactants but preferably one or more nonionic surfactants and excluding cationic, amphoteric or zwitterionic surfactants; optionally one or more further constituents selected coloring agents, fragrances and fragrance solubilizers, viscosity modifying agents including one or more thickeners, pH adjusting agents and pH buffers including organic and inorganic salts, optical brighteners, opacifying agents, hydrotropes, abrasives, and preservatives, as well as other optional constituents known to the art; and the balance, water, wherein water comprises at least 80% wt. of the composition.

2012-06-05

61

Dipeptides promote folding and peptide binding of MHC class I molecules  

PubMed Central

MHC class I molecules bind only those peptides with high affinity that conform to stringent length and sequence requirements. We have now investigated which peptides can aid the in vitro folding of class I molecules, and we find that the dipeptide glycyl-leucine efficiently supports the folding of HLA-A*02:01 and H-2Kb into a peptide-receptive conformation that rapidly binds high-affinity peptides. Treatment of cells with glycyl-leucine induces accumulation of peptide-receptive H-2Kb and HLA-A*02:01 at the surface of cells. Other dipeptides with a hydrophobic second amino acid show similar enhancement effects. Our data suggest that the dipeptides bind into the F pocket like the C-terminal amino acids of a high-affinity peptide.

Saini, Sunil Kumar; Ostermeir, Katja; Ramnarayan, Venkat Raman; Schuster, Heiko; Zacharias, Martin; Springer, Sebastian

2013-01-01

62

Dipeptides promote folding and peptide binding of MHC class I molecules.  

PubMed

MHC class I molecules bind only those peptides with high affinity that conform to stringent length and sequence requirements. We have now investigated which peptides can aid the in vitro folding of class I molecules, and we find that the dipeptide glycyl-leucine efficiently supports the folding of HLA-A*02:01 and H-2K(b) into a peptide-receptive conformation that rapidly binds high-affinity peptides. Treatment of cells with glycyl-leucine induces accumulation of peptide-receptive H-2K(b) and HLA-A*02:01 at the surface of cells. Other dipeptides with a hydrophobic second amino acid show similar enhancement effects. Our data suggest that the dipeptides bind into the F pocket like the C-terminal amino acids of a high-affinity peptide. PMID:24003162

Saini, Sunil Kumar; Ostermeir, Katja; Ramnarayan, Venkat Raman; Schuster, Heiko; Zacharias, Martin; Springer, Sebastian

2013-09-17

63

Nucleotide Composition of Nucleic Acids of Fungi II. Deoxyribonucleic Acids  

PubMed Central

Storck, Roger (The University of Texas, Austin). Nucleotide composition of nucleic acids from fungi. II. Deoxyribonucleic acids. J. Bacteriol. 91:227–230. 1966.—The nucleotide composition of the deoxyribonucleic acids (DNA) present in extracts of 30 species of fungi was determined. The results were analyzed, together with those in the literature. It was found that the content, in moles per cent of guanine plus cytosine (GC content), varied from 38 to 63% in a distribution composed of 9 species of zygomycetes, 14 of ascomycetes, and 9 each of deuteromycetes and basidiomycetes. The GC content ranges were: 38 to 48% for the zygomycetes, 38 to 54% for the ascomycetes, 47 to 62% for the deuteromycetes, and 44 to 63% for the basidiomycetes. The GC content ranged from 38 to 40% for four Mucor species. The base composition of fungal DNA appears, therefore, to have a taxonomic and phylogenetic significance.

Storck, Roger

1966-01-01

64

Structural characterization of a dipeptide compound with immunostimulant activity: 3-(5-thioxo-L-prolyl)-L-thiazolidine-4-carboxylic acid.  

PubMed

The structural characteristics of an immunostimulating agent (3-(5-thioxo-L-prolyl)-L-thiazolidine-4-carboxylic acid) have been established using a combination of 1H and 13C NMR spectroscopy, molecular mechanic calculations (in vacuo and in solution) and X-ray crystallographic analyses. Conformational calculations and NMR spectra identify two classes of conformers, cis and trans, around the peptide bond between the rings, while in the solid state only the cis form has been found. PMID:13679183

Artali, R; Bombieri, G; Meneghetti, F; Nava, D; Ragg, E; Stradi, R

2003-09-01

65

Relative stability of major types of beta-turns as a function of amino acid composition: a study based on Ab initio energetic and natural abundance data.  

PubMed

Folding properties of small globular proteins are determined by their amino acid sequence (primary structure). This holds both for local (secondary structure) and for global conformational features of linear polypeptides and proteins composed from natural amino acid derivatives. It thus provides the rational basis of structure prediction algorithms. The shortest secondary structure element, the beta-turn, most typically adopts either a type I or a type II form, depending on the amino acid composition. Herein we investigate the sequence-dependent folding stability of both major types of beta-turns using simple dipeptide models (-Xxx-Yyy-). Gas-phase ab initio properties of 16 carefully selected and suitably protected dipeptide models (for example Val-Ser, Ala-Gly, Ser-Ser) were studied. For each backbone fold most probable side-chain conformers were considered. Fully optimized 321G RHF molecular structures were employed in medium level [B3LYP/6-311++G(d,p)//RHF/3-21G] energy calculations to estimate relative populations of the different backbone conformers. Our results show that the preference for beta-turn forms as calculated by quantum mechanics and observed in Xray determined proteins correlates significantly. PMID:12794897

Perczel, András; Jákli, Imre; McAllister, Michael A; Csizmadia, Imre G

2003-06-01

66

157 nm Photodissociation of a Complete Set of Dipeptide Ions Containing C-Terminal Arginine  

NASA Astrophysics Data System (ADS)

Twenty singly-charged dipeptide ions with C-terminal arginine were photodissociated with 157 nm light and their tandem mass spectra recorded. Many of the small product ions that were observed are standard peptide fragments that have been commonly seen in VUV photodissociation studies. However, the study of a library of dipeptides containing all 20 N-terminal amino acids enabled the recognition of trends associated with the occurrence of w-, v-, and immonium ions, the observation of competition between forming N- and C-terminal fragments in dipeptide RR, and the identification of some unusual fragment ions appearing at masses of 183, 187, 196, and 197 Da. A highly accurate internal calibration of the photodissociation TOF-TOF data enabled molecular formulae for these four product ions to be derived. Their proposed structures reflect the rather high-energy nature of this fragmentation phenomenon.

He, Yi; Webber, Nathaniel; Reilly, James P.

2013-05-01

67

Abnormal fatty acid composition and human atherosclerosis  

PubMed Central

Eighty patients with aorto-iliac / femoro-popliteal atherosclerosis were collected to examine in detail their plasma cholesteryl ester fatty acid compositions and to compare them with the incidence of ischaemic heart disease through a 4-year follow-up. Various other biochemical and rheological parameters were also measured to see if these might explain any association between the abnormal fatty acid pattern and ischaemic heart disease. The abnormal fatty acid pattern was specifically and generally similar to that found in essential fatty acid (EFA) deficient animals and children as shown by the increase of the specific trienoic acid (C.20: 3?9) by reduced linoleic acid concentrations, and by an increase of C.18 and C.16 monoenoic acids (oleic and palmitoleic), but not of their corresponding saturated forms, stearic and palmitic. The results suggest that the abnormal fatty acid composition resulted from an increased synthesis of monoenoic acids and monounsaturase activity, coupled with a relative inadequacy of linoleic acid. The patients with a reduced concentration of linoleic acid (<35%) subsequently had a higher incidence of myocardial infarction. No significant correlations were found between the fatty acid concentration and various other biochemical or rheological parameters except marginally between linoleic acid and platelet adhesiveness. Only the linoleic acid concentration distinguished between the patients with and without myocardial infarction. A marked inverse correlation was found, however, between the monoenoic and linoleic acid concentration, without parallel changes in other fatty acids. It seems that as in animals, a balance exists between EFA and monoenoic pathways which are known to compete for the same desaturase systems and acyl sites. It appears that human EFA requirements and effects need to be considered not only by their intake and metabolism, but also through individual factors which vary the monoenoic concentrations and monounsaturase activity. Since these factors include several currently associated with human atherosclerosis the question arises of whether the EFA-monoenoic balance is one link between them and the pathology of the arterial occlusions and myocardial infarction.

Kingsbury, K. J.; Brett, C.; Stovold, R.; Chapman, A.; Anderson, J.; Morgan, D. M.

1974-01-01

68

Cellular fatty acid composition of Plesiomonas shigelloides.  

PubMed Central

The cellular fatty acid compositions of 29 strains of Plesiomonas shigelloides and 5 strains of Aeromonas hydrophila were studied. The cellular fatty acid compositions of all the Plesiomonas strains were identical and characterized by the presence of hexadecanoate (16:0) (33%), hexadecenoate (16:1) (28%), octadecenoate (18:1) (9%), and octadecanoate (18:0) (6%). The cellular fatty acid composition of A. hydrophila was similar to that of the Plesiomonas strains, except that the former contained an average of 25% 16:0, 29% 16:1, 12% 18:1, and 2% 18:0 acids compared with 33, 28, 9, and 6%, respectively, for the latter. The percentage ratios of 16:1 to 16:0 and 18:1 to 18:0 could be used to differentiate P. shigelloides from A. hydrophila. These ratios were 0.8 and 1.5 for the former and 1.2 and 6.0 for the latter.

Chou, S; Aldova, E; Kasatiya, S

1991-01-01

69

Effect of thermal treatment on the structure and the biomedical properties of polyetherurethane film containing dipeptides of L-serine.  

PubMed

Prepolymers which were obtained by the reaction of 4,4'-diphenylmethane diisocyanate (MDI) with polytetramethylene glycol (PTMG) and polyethylene glycol (PEG) were chain-extended by the reaction with the linear or cyclic dipeptide of L-serine to yield a novel polyetherurethane containing dipeptide segments. In these polyetherurethanes, spherulites, fibrous structures, and needle-like crystals were formed according to the conditions used. Polyetherurethanes containing the cyclic dipeptide segments exhibit a thermally stable conformation when cast from solution at room temperature. On the other hand, polyetherurethanes containing the linear dipeptide segments exhibit a thermally stable conformation only after annealing. The properties of polyetherurethanes were elucidated by investigation of their morphology by electron microscopy, surface composition by electron spectroscopy for chemical analysis, hydrogen-bonding properties by i.r. spectroscopy, and degree of crystallinity by differential scanning calorimetry. The antithrombogenicity of polyetherurethane films containing linear dipeptides was increased by annealing. Their oxygen permeability was controlled by the linear or cyclic dipeptide segments or by annealing. The urea permeability of hydrophilic polyetherurethane film was easily controlled by the casting conditions and molecular weight of the polyether component. The relationship between the morphology and biomedical properties of these polyetherurethane films is discussed. PMID:3931716

Mori, A; Imanishi, Y; Ito, T; Sakaoku, K

1985-09-01

70

Enzymatical and microbial degradation of cyclic dipeptides (diketopiperazines).  

PubMed

Diketopiperazines (DKPs) are cyclic dipeptides, representing an abundant class of biologically active natural compounds. Despite their widespread occurrence in nature, little is known about their degradation. In this study, the enzymatical and microbial cleavage of DKPs was investigated. Peptidase catalyzed hydrolysis of certain DKPs was formerly reported, but could not be confirmed in this study. While testing additional peptidases and DKPs no degradation was detected, indicating peptidase stability of the peptide bond in cyclic dipeptides. Besides confirmation of the reported degradation of cyclo(l-Asp-l-Phe) by Paenibacillus chibensis (DSM 329) and Streptomyces flavovirens (DSM 40062), cleavage of cyclo(l-Asp-l-Asp) by DSM 329 was detected. Other DKPs were not hydrolyzed by both strains, demonstrating high substrate specificity. The degradation of cyclo(l-Asp-l-Phe) by DSM 40062 was shown to be inducible. Three strains, which are able to hydrolyze hydantoins and dihydropyrimidines, were identified for the degradation of DKPs: Leifsonia sp. K3 (DSM 27212) and Bacillus sp. A16 (DSM 25052) cleaved cyclo(dl-Ala-dl-Ala) and cyclo(l-Gly-l-Phe), and Rhizobium sp. NA04-01 (DSM 24917) degraded cyclo(l-Asp-l-Phe), cyclo(l-Gly-l-Phe) and cyclo(l-Asp-l-Asp). The first enantioselective cleavage of cyclo(dl-Ala-dl-Ala) was detected with the newly isolated strains Paenibacillus sp. 32A (DSM 27214) and Microbacterium sp. 40A (DSM 27211). Cyclo(l-Ala-d-Ala) and cyclo(l-Ala-l-Ala) were completely degraded, whereas the enantiomer cyclo(d-Ala-d-Ala) was not attacked. Altogether, five bacterial strains were newly identified for the cleavage of DKPs. These bacteria may be of value for industrial purposes, such as degradation of undesirable DKPs in food and drugs and production of (enantiopure) dipeptides and amino acids. PMID:24001323

Perzborn, Mareike; Syldatk, Christoph; Rudat, Jens

2013-01-01

71

Enzymatical and microbial degradation of cyclic dipeptides (diketopiperazines)  

PubMed Central

Diketopiperazines (DKPs) are cyclic dipeptides, representing an abundant class of biologically active natural compounds. Despite their widespread occurrence in nature, little is known about their degradation. In this study, the enzymatical and microbial cleavage of DKPs was investigated. Peptidase catalyzed hydrolysis of certain DKPs was formerly reported, but could not be confirmed in this study. While testing additional peptidases and DKPs no degradation was detected, indicating peptidase stability of the peptide bond in cyclic dipeptides. Besides confirmation of the reported degradation of cyclo(l-Asp-l-Phe) by Paenibacillus chibensis (DSM 329) and Streptomyces flavovirens (DSM 40062), cleavage of cyclo(l-Asp-l-Asp) by DSM 329 was detected. Other DKPs were not hydrolyzed by both strains, demonstrating high substrate specificity. The degradation of cyclo(l-Asp-l-Phe) by DSM 40062 was shown to be inducible. Three strains, which are able to hydrolyze hydantoins and dihydropyrimidines, were identified for the degradation of DKPs: Leifsonia sp. K3 (DSM 27212) and Bacillus sp. A16 (DSM 25052) cleaved cyclo(dl-Ala-dl-Ala) and cyclo(l-Gly-l-Phe), and Rhizobium sp. NA04-01 (DSM 24917) degraded cyclo(l-Asp-l-Phe), cyclo(l-Gly-l-Phe) and cyclo(l-Asp-l-Asp). The first enantioselective cleavage of cyclo(dl-Ala-dl-Ala) was detected with the newly isolated strains Paenibacillus sp. 32A (DSM 27214) and Microbacterium sp. 40A (DSM 27211). Cyclo(l-Ala-d-Ala) and cyclo(l-Ala-l-Ala) were completely degraded, whereas the enantiomer cyclo(d-Ala-d-Ala) was not attacked. Altogether, five bacterial strains were newly identified for the cleavage of DKPs. These bacteria may be of value for industrial purposes, such as degradation of undesirable DKPs in food and drugs and production of (enantiopure) dipeptides and amino acids.

2013-01-01

72

Ocular Sustained Release Nanoparticles Containing Stereoisomeric Dipeptide Prodrugs of Acyclovir  

PubMed Central

Abstract Purpose The objective of this study was to develop and characterize polymeric nanoparticles of appropriate stereoisomeric dipeptide prodrugs of acyclovir (L-valine-L-valine-ACV, L-valine-D-valine-ACV, D-valine-L-valine-ACV, and D-valine-D-valine-ACV) for the treatment of ocular herpes keratitis. Methods Stereoisomeric dipeptide prodrugs of acyclovir (ACV) were screened for bioreversion in various ocular tissues, cell proliferation, and uptake across the rabbit primary corneal epithelial cell line. Docking studies were carried out to examine the affinity of prodrugs to the peptide transporter protein. Prodrugs with optimum characteristics were selected for the preparation of nanoparticles using various grades of poly (lactic-co-glycolic acid) (PLGA). Nanoparticles were characterized for the entrapment efficiency, surface morphology, size distribution, and in vitro release. Further, the effect of thermosensitive gels on the release of prodrugs from nanoparticles was also studied. Results L-valine-L-valine-ACV and L-valine-D-valine-ACV were considered to be optimum in terms of enzymatic stability, uptake, and cytotoxicity. Docking results indicated that L-valine in the terminal position increases the affinity of the prodrugs to the peptide transporter protein. Entrapment efficiency values of L-valine-L-valine-ACV and L-valine-D-valine-ACV were found to be optimal with PLGA 75:25 and PLGA 65:35 polymers, respectively. In vitro release of prodrugs from nanoparticles exhibited a biphasic release behavior with initial burst phase followed by sustained release. Dispersion of nanoparticles in thermosensitive gels completely eliminated the burst release phase. Conclusion Novel nanoparticulate systems of dipeptide prodrugs of ACV suspended in thermosensitive gels may provide sustained delivery after topical administration.

Jwala, Jwala; Boddu, Sai H.S.; Shah, Sujay; Sirimulla, Suman; Pal, Dhananjay

2011-01-01

73

Nucleotide Composition of Nucleic Acids of Fungi I. Ribonucleic Acids  

PubMed Central

Storck, Roger (The University of Texas, Austin). Nucleotide composition of nucleic acids from fungi. I. Ribonucleic acids. J. Bacteriol. 90:1260–1264. 1965.—The nucleotide composition of the ribonucleic acids (RNA) present in extracts of 26 species of fungi was determined. The results were analyzed, together with those in the literature. It was found that the content in moles per cent of guanine plus cytosine (GC content) varied from 44.1 to 60.5 in a distribution composed of 8 species of zygomycetes, 10 of ascomycetes, 11 of deuteromycetes, and 8 of basidiomycetes. The GC-content range and average were, respectively, 44.1 to 49.3 and 46.4 for the zygomycetes, 47.4 to 54.4 and 50.2 for the ascomycetes, 48.2 to 54.5 and 51.6 for the deuteromycetes, and 50.4 to 60.5 and 52.4 for the basidiomycetes. The GC content averaged 45.6 and ranged from 44.1 to 46.3 for four Mucor species. In addition, GC contents significantly lower than 50 were also encountered in some species of Hemiascomycetidae, suggesting that AT type RNA is not uncommon in fungi. It was proposed that the base composition of fungal RNA might have a taxonomic and phylogenetic significance.

Storck, Roger

1965-01-01

74

Effects of dipeptides administered to a perfused area of the skin in Angora goats.  

PubMed

The effect of dipeptide infusion on mohair growth of Angora goats was investigated using a skin perfusion technique. Six Angora wethers (average BW 32 +/- 2 kg) were implanted bilaterally with silicon catheters into the superficial branches of the deep circumflex iliac artery and to the deep circumflex iliac vein. For the first 14 d of the experiment, animals received infusions into the deep circumflex iliac arteries of either a mixture of Met-Leu and Lys-Leu (one side) or saline (other side). Infusion rates of amino acids were .72 mg/h Met-Leu and .72 mg/h Lys-Leu. The area of skin supplied by the deep circumflex iliac artery was approximately 300 cm2. An area of 150 cm2 within the perfused region was used to determine mohair growth. Two weeks after the cessation of infusions, perfused areas were shorn, and greasy and clean mohair production, staple length, and diameter were determined. Greasy and clean mohair production from the perfused region were increased by dipeptide infusion compared to the side infused with saline (1.91 vs 1.66 g, P < .05 and 1.56 vs 1.31 g, P < .04, respectively). No significant changes were observed in mohair diameter; however, staple length tended to increase as a result of dipeptide infusion (18.0 vs 16.1, P < .1). Decreased concentrations of Met, Cys, Lys, Phe, Val, Ileu, Leu, and Arg were observed in the venous blood taken from the deep circumflex iliac vein on the side infused with the amino acid mixture compared with blood taken from the saline side (P < .05). There were no treatment differences in triiodothyronine, thyroxine, or insulin concentrations in venous blood taken from the deep circumflex iliac vein. Direct skin infusion with dipeptide may have resulted in mobilization of amino acids for increased protein synthesis, or the infused dipeptides may have acted as growth promoters stimulating skin amino acid uptake and protein synthesis. PMID:9374322

Pierzynowski, S G; Puchala, R; Sahlu, T

1997-11-01

75

Dietary fat and the fatty acid composition of tissue lipids  

Microsoft Academic Search

Some characteristics of the fatty acid composition of animal tissue lipids are described and the origins of tissue fatty acids\\u000a are discussed briefly. The effect of dietary fat on composition of tissue lipids is discussed. Types of dietary fatty acids\\u000a for which experimental work is described include polyunsaturated fatty acids, short-chain fatty acids, fatty acids with chain\\u000a length greater than

K. K. Carroll

1965-01-01

76

[Chiral separation of dipeptides by capillary electrophoresis].  

PubMed

Peptides are increasingly used as pharmaceutical agents. Many small peptides are the essential compounds in biological systems. Direct chiral separation of dipeptide derivatives using 9-(2-carbazole) ethyl chloroformate (CEOC) as the derivatizing agent by capillary electrophoresis (CE) with beta-cyclodextrin (beta-CD) and sodium deoxycholate (SDC) as chiral selectors has been developed. It has been well recognized that the combination of the binary selectors can enhance the selectivity and resolution instead of either beta-CD or SDC alone. The molar ratio of the binary chiral selectors, the buffer concentration and pH of Tris-H3PO4, organic modifier were studied and optimized. Complete chiral separations for 14 dipeptide derivatives using beta-CD and SDC as binary chiral selectors were obtained. The results indicated that each pair of D/L chiral resolution was more than 3.63, and the highest resolution for Gly-Ala was 43.14. PMID:16830473

Cheng, Yan; Bai, Min; Wang, Xinmei; Ming, Yongfei; You, Jinmao

2006-03-01

77

Characterization of N?-Fmoc-protected dipeptide isomers by electrospray ionization tandem mass spectrometry (ESI-MS(n)): effect of protecting group on fragmentation of dipeptides.  

PubMed

A series of positional isomeric pairs of Fmoc-protected dipeptides, Fmoc-Gly-Xxx-OY/Fmoc-Xxx-Gly-OY (Xxx=Ala, Val, Leu, Phe) and Fmoc-Ala-Xxx-OY/Fmoc-Xxx-Ala-OY (Xxx=Leu, Phe) (Fmoc=[(9-fluorenylmethyl)oxy]carbonyl) and Y=CH(3)/H), have been characterized and differentiated by both positive and negative ion electrospray ionization ion-trap tandem mass spectrometry (ESI-IT-MS(n)). In contrast to the behavior of reported unprotected dipeptide isomers which mainly produce y(1)(+) and/or a(1)(+) ions, the protonated Fmoc-Xxx-Gly-OY, Fmoc-Ala-Xxx-OY and Fmoc-Xxx-Ala-OY yield significant b(1)(+) ions. These ions are formed, presumably with stable protonated aziridinone structures. However, the peptides with Gly- at the N-terminus do not form b(1)(+) ions. The [M+H](+) ions of all the peptides undergo a McLafferty-type rearrangement followed by loss of CO(2) to form [M+H-Fmoc+H](+). The MS(3) collision-induced dissociation (CID) of these ions helps distinguish the pairs of isomeric dipeptides studied in this work. Further, negative ion MS(3) CID has also been found to be useful for differentiating these isomeric peptide acids. The MS(3) of [M-H-Fmoc+H](-) of isomeric peptide acids produce c(1)(-), z(1)(-) and y(1)(-) ions. Thus the present study of Fmoc-protected peptides provides additional information on mass spectral characterization of the dipeptides and distinguishes the positional isomers. PMID:21698678

Ramesh, M; Raju, B; Srinivas, R; Sureshbabu, V V; Vishwanatha, T M; Hemantha, H P

2011-07-30

78

Amino Acid Composition of Crystalline Botulinum Toxin, Type A.  

National Technical Information Service (NTIS)

The amino acid composition of botulinum toxin, type A, was determined with the aid of the automatic amino acid analyzer. The results are compared with an earlier largely microbiological analysis. (Author)

D. Stefanye

1965-01-01

79

The effect of plant protein-based diet supplemented with dipeptide or free amino acids on digestive tract morphology and PepT1 and PepT2 expressions in common carp (Cyprinus carpio L.).  

PubMed

Common carp (Cyprinus carpio) of average body mass 0.07+/-0.02 g were fed three formulated diets: wheat gluten protein-based diet supplemented with Lys-Gly dipeptide (PP), wheat gluten protein-based diet supplemented with free lysine and glycine (AA), and a wheat gluten protein-based control diet without lysine supplementation (CON), frozen zooplankton (Z) (restricted diet), and a commercial starter food Aglo Norse (AN). After 4 weeks of experimental feeding, fish fed AN diet showed the highest body mass and length. Significantly lower mass occurred in groups fed PP, AA, CON, and Z. Fish fed CON diet showed the lowest intestinal folds and the highest number of mucous cells. Fish fed PP diet showed a significantly higher number of gastrin/cholecystokinin (CCK) positive cells. The diameter of lipid vacuoles in hepatocyte cytoplasm of fish fed formulated diets (PP, AA and CON) was significantly higher than in fish fed zooplankton (Z) and the commercial diet (AN). Hepatocytes of fish fed AA and CON showed a higher nucleus proliferation rate than in the other experimental groups. The quantitative analysis of the number of proliferating cell nuclear antigen (PCNA) and caspase-3(rabbit polyclonal antibody CPP-32)-positive cells showed that the highest proliferation rate was accompanied by the high apoptosis in the intestine of fish fed AA and CON. After 4 weeks of experimental feeding the highest relative expression of PepT1 gene was observed in fish fed PP diet, while the lowest expression occurred in fish fed CON. Feeding carp plant protein-based diet supplemented with Lys-Gly dipeptide (PP) had a beneficial influence on fish growth and metabolism in the digestive tract as compared to fish fed control diet without lysine supplementation (CON). PMID:20542130

Ostaszewska, Teresa; Dabrowski, Konrad; Kamaszewski, Maciej; Grochowski, Piotr; Verri, Tiziano; Rzepkowska, Ma?gorzata; Wolnicki, Jacek

2010-10-01

80

Total cellular fatty acid composition of cultured Pneumocystis carinii.  

PubMed Central

Oleic acid makes up > 50% of the total fatty acids of Pneumocystis carinii grown on WI-38 cells. Oleic acid levels increased in parallel with increasing trophozoites over 7 days in culture. The fatty acid composition of P. carinii resembles that of certain fungi but differs from those of lung surfactant lipid, host cells, and fetal bovine serum.

Paulsrud, J R; Queener, S F; Bartlett, M S; Smith, J W

1993-01-01

81

Kinetics of degradation and oil solubility of ester prodrugs of a model dipeptide (Gly-Phe)  

Microsoft Academic Search

Oil-based depot formulations may constitute a future delivery method for small peptides. Thus, a requirement is attainment of sufficient oil solubility for such active compounds. A model dipeptide (Gly-Phe) has been converted into lipophilic prodrugs by esterification at the C-terminal carboxylic acid group. The decomposition kinetics of octyl ester of Gly-Phe (IV) has been investigated at pH 7.4 (37°C) and

Susan Weng Larsen; Michael Ankersen; Claus Larsen

2004-01-01

82

Intramolecular condensation reactions in protonated dipeptides: Carbon monoxide, water, and ammonia losses in competition  

Microsoft Academic Search

The elimination of carbon monoxide and water from a series of protonated dipeptides, [XxxYyy + H]+, is investigated by tandem mass spectrometry experiments and density functional theory. The combined results show that CO\\u000a loss occurs on the a1-y1 pathway, which begins by rearrangement of the added proton to the amide N-atom and creates the proton-bound dimer of an amino\\u000a acid

Francesco Pingitore; Michael J. Polce; Ping Wang; Chrys Wesdemiotis; Béla Paizs

2004-01-01

83

Discriminability of tryptophan containing dipeptides using quantum control  

NASA Astrophysics Data System (ADS)

We show that the coherent manipulation of molecular wavepackets in the excited states of trp-containing dipeptides allows efficient discrimination among them. Optimal dynamic discrimination fails, however, for some dipeptide couples. When considering the limited spectral resources at play (3 nm bandwidth at 266 nm), we discuss the concept of discriminability, which appears uncorrelated to both static spectra and relaxation lifetimes.

Afonina, S.; Nenadl, O.; Rondi, A.; Bonacina, L.; Extermann, J.; Kiselev, D.; Dolamic, I.; Burgi, T.; Wolf, J. P.

2013-06-01

84

Fatty Acid Composition and Trans Fatty Acids in Crisps and Cakes in Turkey's Markets  

Microsoft Academic Search

In this study, trans fatty acid and fatty acid composition of 57 crisps and 50 cakes sold in the markets in Turkey were determined. C 18:1, oleic acid, was the major fatty acid in all crisps and cake samples. The percentages of saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), and polyunsaturated fatty acids (PUFAs) ranged between 27.98–46.57, 35.73–47.57, and

Yavuz S. Cakmak; Gokalp O. Guler; Sakir Yigit; Gokhan Caglav; Abdurrahman Aktumsek

2011-01-01

85

Self-assembly and gelation properties of glycine/leucine Fmoc-dipeptides.  

PubMed

Self-assembly of aromatic peptide amphiphiles is known to be driven by a combination of ?-? stacking of the aromatic moieties and hydrogen bonding between the peptide backbones, with possible stabilisation from the amino acid side chains. Phenylalanine-based Fmoc-dipeptides have previously been reported for their characteristic apparent pKa transitions, which were shown to coincide with significant structural and morphological changes that were peptide sequence dependent. Here, phenylalanine was replaced by leucine and the effect on the self-assembling behaviour of Fmoc-dipeptides was measured using potentiometry, fluorescence and infrared spectroscopy, transmission electron microscopy, X-ray scattering and shear rheometry. This study provides additional cues towards the elucidation of the sequence-structure relationship in self-assembling aromatic peptide amphiphiles. PMID:24085660

Tang, Claire; Ulijn, Rein V; Saiani, Alberto

2013-10-01

86

Dipeptides and diketopiperazines in the Yamato-791198 and Murchison carbonaceous chondrites.  

PubMed

The Yamato-791198 and Murchison carbonaceous chondrites were analyzed for dipeptides and diketopiperazines as well as amino acids and hydantoins by gas chromatography combined with mass spectrometry. Glycylglycine (gly-gly) and cyclo(gly-gly) were detected at the concentrations of 11 and 18 pmol g-1, respectively, in Yamato-791198, and 4 and 23 pmol g-1, respectively, in Murchison. No other dipeptide and diketopiperazine were detected. Five hydantoins were detected at 8 to 65 pmol g-1 in Yamato-791198 and seven in Murchison at 6 to 104 pmol g-1. Total concentration of the glycine (gly) dimers is approximately four orders of magnitude less than the concentration of free gly in Yamato-791198, and three orders of magnitude less than that in Murchison. The absence of L- and LL-stereoisomers of dipeptides consisting of protein amino acids indicates that gly-gly and cyclo(gly-gly) detected are native to the chondries and not from terrestrial contaminants. A possibility was discussed that the gly dimers might have been formed by condensation of gly monomers but not formed through N-carboxyanhydrides of gly. PMID:12185674

Shimoyama, Akira; Ogasawara, Ryo

2002-04-01

87

Polarizable molecular dynamics simulations of aqueous dipeptides.  

PubMed

Molecular dynamics simulations were carried out for concentrated aqueous solutions of three dipeptides: Gly-Ala, Gly-Pro, and Ala-Pro. The simulations were performed using both polarizable and nonpolarizable force fields, as a method of assessing the effects of polarization in a well-characterized biomolecular system, and to determine whether the models are adequate to reproduce observed aggregation behavior. The structure and dynamics of both solute and solvent were analyzed and the results compared to experiment, including neutron diffraction measurements of peptide aggregation. The polarizable water is depolarized in concentrated peptide solutions, reflecting its ability to adapt to heterogeneous electrostatic environments. Significant differences between the polarizable and nonpolarizable models are found in terms of both the structure and the dynamics of water as a solvent. Although the water shows more realistic structure and dynamics in the polarizable simulations, consistent with enhanced peptide-water interaction, the peptide aggregation behavior agrees less well with the experiment. Neither model successfully reproduces the experimentally observed dipeptide aggregation behavior. PMID:22747103

Kucukkal, Tugba G; Stuart, Steven J

2012-08-01

88

Amino acid composition of proteins reduces deleterious impact of mutations.  

PubMed

The evolutionary origin of amino acid occurrence frequencies in proteins (composition) is not yet fully understood. We suggest that protein composition works alongside the genetic code to minimize impact of mutations on protein structure. First, we propose a novel method for estimating thermodynamic stability of proteins whose sequence is constrained to a fixed composition. Second, we quantify the average deleterious impact of substituting one amino acid with another. Natural proteome compositions are special in at least two ways: 1) Natural compositions do not generate more stable proteins than the average random composition, however, they result in proteins that are less susceptible to damage from mutations. 2) Natural proteome compositions that result in more stable proteins (i.e. those of thermophiles) are also tuned to have a higher tolerance for mutations. This is consistent with the observation that environmental factors selecting for more stable proteins also enhance the deleterious impact of mutations. PMID:24108121

Hormoz, Sahand

2013-01-01

89

Amino acid composition of proteins reduces deleterious impact of mutations  

PubMed Central

The evolutionary origin of amino acid occurrence frequencies in proteins (composition) is not yet fully understood. We suggest that protein composition works alongside the genetic code to minimize impact of mutations on protein structure. First, we propose a novel method for estimating thermodynamic stability of proteins whose sequence is constrained to a fixed composition. Second, we quantify the average deleterious impact of substituting one amino acid with another. Natural proteome compositions are special in at least two ways: 1) Natural compositions do not generate more stable proteins than the average random composition, however, they result in proteins that are less susceptible to damage from mutations. 2) Natural proteome compositions that result in more stable proteins (i.e. those of thermophiles) are also tuned to have a higher tolerance for mutations. This is consistent with the observation that environmental factors selecting for more stable proteins also enhance the deleterious impact of mutations.

Hormoz, Sahand

2013-01-01

90

Fatty Acid Composition and Volatile Constituents of Protaetia brevitarsis Larvae  

PubMed Central

A total of 48 different volatile oils were identified form P. brevitarsis larvae by gas chromatography/mass spectrometry (GC/MS). Acids (48.67%) were detected as the major group in P. brevitarsis larvae comprising the largest proportion of the volatile compounds, followed by esters (19.84%), hydrocarbons (18.90%), alcohols (8.37%), miscellaneous (1.71%), aldehydes (1.35%) and terpenes (1.16%). The major volatile constituents were 9-hexadecenoic acid (16.75%), 6-octadecenoic acid (14.88%) and n-hexadecanoic acid (11.06%). The composition of fatty acid was also determined by GC analysis and 16 fatty acids were identified. The predominant fatty acids were oleic acid (C18:1, 64.24%) followed by palmitic acid (C16:0, 15.89%), palmitoleic acid (C16:1, 10.43%) and linoleic acid (C18:2, 4.69%) constituting more than 95% of total fatty acids. The distinguished characteristic of the fatty acid profile of P. brevitarsis larvae was the high proportion of unsaturated fatty acid (80.54% of total fatty acids) versus saturated fatty acids (19.46% of total fatty acids). Furthermore, small but significant amounts of linoleic, linolenic and ?-linolenic acids bestow P. brevitarsis larvae with considerable nutritional value. The novel findings of the present study provide a scientific basis for the comprehensive utilization of the insect as a nutritionally promising food source and a possibility for more effective utilization.

Yeo, Hyelim; Youn, Kumju; Kim, Minji; Yun, Eun-Young; Hwang, Jae-Sam; Jeong, Woo-Sik; Jun, Mira

2013-01-01

91

Tryptophan-containing dipeptides are C-domain selective inhibitors of angiotensin converting enzyme.  

PubMed

Somatic angiotensin-converting enzyme (ACE) contains two active sites, the C- and N-domain, from which the C-domain is supposed to play a major role in blood pressure regulation and is therefore a promising pharmacological target to reduce blood pressure without side-effects. We report for the first time that tryptophan-containing dipeptides such as Ile-Trp or Val-Trp, which were recently found in food protein hydrolysates, are selective and competitive inhibitors for the C-domain with a selectivity factor of 40 and 70, respectively. Structure-activity studies showed that an N-terminal aliphatic amino acid and a tryptophan moiety in the P2' position are favourable structures for C-domain inhibition in dipeptides. In contrast, the lactotripeptides Ile-Pro-Pro and Val-Pro-Pro, which were widely used as ingredients for hypotensive food, showed a slight selectivity for the N-domain. Hence, tryptophan containing dipeptides are interesting ingredients for functional foods as a natural prevention for hypertension with reduced side effects due to its selective inhibition of the C-domain. PMID:25053098

Lunow, Diana; Kaiser, Susanne; Rückriemen, Jana; Pohl, Christoph; Henle, Thomas

2015-01-01

92

Kinetics of degradation and oil solubility of ester prodrugs of a model dipeptide (Gly-Phe).  

PubMed

Oil-based depot formulations may constitute a future delivery method for small peptides. Thus, a requirement is attainment of sufficient oil solubility for such active compounds. A model dipeptide (Gly-Phe) has been converted into lipophilic prodrugs by esterification at the C-terminal carboxylic acid group. The decomposition kinetics of octyl ester of Gly-Phe (IV) has been investigated at pH 7.4 (37 degrees C) and IV was shown to degrade by first-order kinetics via two parallel pathways (1) intramolecular aminolysis resulting in formation of a 2,5-diketopiperazine and (2) hydrolysis of the ester bond producing the dipeptide. The cyclisation reaction was dominating in the decomposition of methyl (II) butyl (III) octyl (IV) decyl (V) and dodecyl (VI) esters of Gly-Phe at pH 7.4. However, this degradation pathway was almost negligible for pH below 6. During degradation of the dipeptide esters in 80% human plasma pH 7.4 (37 degrees C) a minimal amount of cyclo(-Gly-Phe) was formed. A faster degradation of the esters in 80% human plasma pH 7.4 compared to those in aqueous solution pH 7.4 was suggested to be due to fast cleavage of the peptide bond. Low oil solubilities for Gly-Phe and the hydrochlorides of the dipeptide esters III and VI were observed. Although the solubility of Gly-Phe in oil solutions was enhanced by hydrophobic ion pairing with sodium decyl sulfonate the oil solubility was still less than 1 mg Gly-Phe/ml. By addition of a solubiliser, 10% N,N-dimethylacetamide (DMA), to Viscoleo the solubility of the HIP complexes increased significantly. The present study indicates that sufficient oil solubility might only be obtained for relatively small peptides by using the prodrug approach in combination with solubility enhancing organic solvents like DMA. PMID:15265509

Larsen, Susan Weng; Ankersen, Michael; Larsen, Claus

2004-08-01

93

A molecular dynamics study of the dielectric properties of aqueous solutions of alanine and alanine dipeptide  

NASA Astrophysics Data System (ADS)

Molecular dynamics simulations were used to compute the frequency-dependent dielectric susceptibility of aqueous solutions of alanine and alanine dipeptide. We studied four alanine solutions, ranging in concentration from 0.13-0.55 mol/liter, and two solutions of alanine dipeptide (0.13 and 0.27 mol/liter). In accord with experiment we find a strong dielectric increment for both solutes, whose molecular origin is shown to be the zwitterionic nature of the solutes. The dynamic properties were analyzed based on a dielectric component analysis into solute, a first hydration shell, and all remaining (bulk) waters. The results of this three component decomposition were interpreted directly, as well as by uniting the solute and hydration shell component to a ``suprasolute'' component. In both approaches three contributions to the frequency-dependent dielectric properties can be discerned. The quantitatively largest and fastest component arises from bulk water [i.e., water not influenced by the solute(s)]. The interaction between waters surrounding the solute(s) (the hydration shell) and bulk water molecules leads to a relaxation process occurring on an intermediate time scale. The slowest relaxation process originates from the solute(s) and the interaction of the solute(s) with the first hydration shell and bulk water. The primary importance of the hydration shell is the exchange of shell and bulk waters; the self-contribution from bound water molecules is comparatively small. While in the alanine solutions the solute-water cross-terms are more important than the solute self-term, the solute contribution is larger in the dipeptide solutions. In the latter systems a much clearer separation of time scales between water and alanine dipeptide related properties is observed. The similarities and differences of the dielectric properties of the amino acid/peptide solutions studied in this work and of solutions of mono- and disaccharides and of the protein ubiquitin are discussed.

Boresch, Stefan; Willensdorfer, Martin; Steinhauser, Othmar

2004-02-01

94

Qualitative mapping of structurally different dipeptide nanotubes.  

PubMed

Biological self-assembled structures are receiving increasing focus within micro- and nanotechnology, for example, as sensing devices, due to the fact that they are cheap to produce and easy to functionalize. Therefore, methods for the characterization of these structures are much needed. In this paper, electrostatic force microscopy (EFM) was used to distinguish between hollow nanotubes formed by self-assembly by a simple aromatic dipeptide, L-phenylalanine, silver-filled peptide-based nanotubes, and silver wires placed on prefabricated SiO2 surfaces with a backgate. The investigation shows that it is possible to distinguish between these three types of structures using this method. Further, an agreement between the detected signal and the structure of the hollow peptide was demonstrated; however only qualitative agreement with the mathematical expressing of the tubes is shown. PMID:18837544

Clausen, Casper Hyttel; Jensen, Jason; Castillo, Jaime; Dimaki, Maria; Svendsen, Winnie Edith

2008-11-01

95

Synthesis and modifications of phosphinic dipeptide analogues.  

PubMed

Pseudopeptides containing the phosphinate moiety (-P(O)(OH)CH(2)-) have been studied extensively, mainly as transition state analogue inhibitors of metalloproteases. The key synthetic aspect of their chemistry is construction of phosphinic dipeptide derivatives bearing appropriate side-chain substituents. Typically, this synthesis involves a multistep preparation of two individual building blocks, which are combined in the final step. As this methodology does not allow simple variation of the side-chain structure, many efforts have been dedicated to the development of alternative approaches. Recent achievements in this field are summarized in this review. Improved methods for the formation of the phosphinic peptide backbone, including stereoselective and multicomponent reactions, are presented. Parallel modifications leading to the structurally diversified substituents are also described. Finally, selected examples of the biomedical applications of the title compounds are given. PMID:23154272

Mucha, Artur

2012-01-01

96

Fatty Acid and Volatile Oil Compositions of Allomyrina dichotoma Larvae  

PubMed Central

Thirty-two different volatile oils were identified from Allomyrina dichotoma (A. dichotoma) larvae by gas chromatography/mass spectrometry (GC/MS). The major volatile components were 2,2,4-trimethyl-3-carboxyisopropyl pentanoic acid isobutyl ester (5.83%), phenol,2,6-bis(a,a-dimethyl ethyl)-4-(1-methyl-1-phenylethyl) (5.72%), heptacosane (5.49%) and phenol,2,4-bis(1-methyl-1-phenylethyl) (5.47%). The composition of the fatty acids in A. dichotoma larvae was also determined by gas chromatography (GC) and fourteen constituents were identified. Oleic acid (19.13%) was the most abundant fatty acid followed by palmitic acid (12.52%), palmitoleic acid (3.71%) and linoleic acid (2.08%) in 100 g of A. dichotoma larvae on a dry weight basis. The quantity of unsaturated fatty acids (64.00%) were higher than that of saturated ones (36.00%). The predominant fatty acids in A. dichotoma consist of monounsaturated fatty acid (MUFA, 57.70%) such as oleic acid, myristoleic acid and palmitoleic acid, followed by saturated fatty acids (36.00%) and polyunsaturated fatty acids (PUFA, 6.50%). In particular, the presence of essential fatty acids, such as linoleic (5.30%) and linolenic acid (0.40%) give A. dichotoma larvae considerable nutritional and functional value and it may be a useful source for food and/or industrial utilization.

Youn, Kumju; Kim, Ji-Young; Yeo, Hyelim; Yun, Eun-Young; Hwang, Jae-Sam; Jun, Mira

2012-01-01

97

Fatty Acid and Volatile Oil Compositions of Allomyrina dichotoma Larvae.  

PubMed

Thirty-two different volatile oils were identified from Allomyrina dichotoma (A. dichotoma) larvae by gas chromatography/mass spectrometry (GC/MS). The major volatile components were 2,2,4-trimethyl-3-carboxyisopropyl pentanoic acid isobutyl ester (5.83%), phenol,2,6-bis(a,a-dimethyl ethyl)-4-(1-methyl-1-phenylethyl) (5.72%), heptacosane (5.49%) and phenol,2,4-bis(1-methyl-1-phenylethyl) (5.47%). The composition of the fatty acids in A. dichotoma larvae was also determined by gas chromatography (GC) and fourteen constituents were identified. Oleic acid (19.13%) was the most abundant fatty acid followed by palmitic acid (12.52%), palmitoleic acid (3.71%) and linoleic acid (2.08%) in 100 g of A. dichotoma larvae on a dry weight basis. The quantity of unsaturated fatty acids (64.00%) were higher than that of saturated ones (36.00%). The predominant fatty acids in A. dichotoma consist of monounsaturated fatty acid (MUFA, 57.70%) such as oleic acid, myristoleic acid and palmitoleic acid, followed by saturated fatty acids (36.00%) and polyunsaturated fatty acids (PUFA, 6.50%). In particular, the presence of essential fatty acids, such as linoleic (5.30%) and linolenic acid (0.40%) give A. dichotoma larvae considerable nutritional and functional value and it may be a useful source for food and/or industrial utilization. PMID:24471102

Youn, Kumju; Kim, Ji-Young; Yeo, Hyelim; Yun, Eun-Young; Hwang, Jae-Sam; Jun, Mira

2012-12-01

98

An efficient method for the synthesis of phenacyl ester-protected dipeptides using neutral alumina-supported sodium carbonate 'Na2 CO3 /n-Al2 O3 '.  

PubMed

In the synthesis of dipeptides (Boc-AA(1)-AA(2)-OPac: AA(1) and AA(2) represent amino acids) protected by phenacyl (Pac) ester, amines and solid bases as the base for the conversion of the trifluoroacetic acid (TFA) salt of the amino component (TFA·H-AA(2)-OPac) into the corresponding free amino component (H-AA(2)-OPac) were examined. The synthesis of a dipeptide (Boc-Ala-Gly-OPac) using amines for the conversion afforded an unsatisfactory yield with by-products. On the other hand, the use of neutral alumina-supported Na(2) CO(3) (Na(2)CO(3) /n-Al(2)O(3)) as a solid base for the conversion provided the dipeptide in a quantitative yield without by-products. The application of Na(2)CO(3) /n-Al2 O3 to the synthesis of some dipeptides protected by Pac ester gave the desired peptides in excellent yields. PMID:23982992

Hashimoto, Chikao; Sugimoto, Kazuhiro; Takahashi, Youhei; Kodomari, Mitsuo

2013-10-01

99

Quantification of cyclic dipeptides from cultures of Lactobacillus brevis R2? by HRGC/MS using stable isotope dilution assay.  

PubMed

Lactic acid bacteria (LAB) play an important role as natural preservatives in fermented food and beverage systems, reducing the application of chemical additives. Thus, investigating their antifungal compounds, such as cyclic dipeptides, has gained prominence. Previous research has primarily focussed on isolation of these compounds. However, their precise quantification will provide further information regarding their antifungal performance in a complex system. To address this, deuterated labelled standards of the cyclic dipeptides cyclo(Leu-Pro), cyclo(Pro-Pro), cyclo(Met-Pro) and cyclo(Phe-Pro) were synthesized, and stable isotope dilution assays were developed, enabling an accurate quantification of cyclo(Leu-Pro), cyclo(Pro-Pro), cyclo(Met-Pro) and cyclo(Phe-Pro) in MRS-broth and wort. Quantitative results showed that, in the Lactobacillus brevis R2? fermented MRS-broth, the concentrations of cyclo(Leu-Pro), cyclo(Pro-Pro) and cyclo(Phe-Pro) were significantly higher (P?dipeptides is related to L. brevis R2? metabolism. Furthermore, this represents the first report of cyclic dipeptides quantification using stable isotope dilution assays in LAB cultures both in vitro and in a food system. PMID:24477717

Axel, Claudia; Zannini, Emanuele; Arendt, Elke K; Waters, Deborah M; Czerny, Michael

2014-04-01

100

Systems, compositions and methods for nucleic acid detection  

US Patent & Trademark Office Database

The invention relates to stretch measurements of nucleic acids and correlating those measurements to the extent of double- and single-stranded content of a nucleic acid of interest, and to compositions, systems, and devices related thereto. In preferred embodiments, one performs the stretch or elasticity measurements under conditions such that one can determine a nucleic acid sequence or the presence of an oligonucleotide in a sample.

2011-02-22

101

Variability for oil and fatty acid composition in castorbean varieties  

Microsoft Academic Search

Thirty-six castorbean varieties were surveyed for oil and fatty acid composition, in order to determine variability of these\\u000a seed compounds. A large variability of seed oil percentage was observed, ranging from 39.6 to 59.5%. Concerning the fatty\\u000a acids, little variability was observed for ricinoleic acid, which was the most abundant in the oil, ranging from 83.65 to\\u000a 90.00%. The other

Luis Carlos da Silva Ramos; Joao Shogiro Tango; Angelo Savi; Nilson Roberto Leal

1984-01-01

102

Conjugated linoleic acid modulates hepatic lipid composition in mice  

Microsoft Academic Search

Conjugated linoleic acid (CLA) is a chemoprotective fatty acid that inhibits mammary, colon, forestomach, and skin carcinogenesis\\u000a in experimental animals. We hypothesize that the ubiquitous chemoprotective actions of dietary CLA in extrahepatic tissues\\u000a are dependent upon its role in modulating fatty acid composition and metabolism in liver, the major organ for lipid metabolism.\\u000a This study begins to evaluate the role

Martha A. Belury; Anna Kempa-Steczko

1997-01-01

103

Quantitative structure-activity relationship modeling of renin-inhibiting dipeptides.  

PubMed

Partial least squares regression method was used to analyze a peptide dataset and construct inhibitory models for renin-inhibitory natural dipeptides. The models were computed with the renin-inhibitory activity as dependent variable (Y) and the peptide structural properties as predictors (X); validation was conducted using cross-validation and permutation tests. The amino acid descriptors were based on the 3- and 5-z scales of 20 coded amino acids to produce models that explained 71.6% of Y with a 33.8% predictive ability and 75.2% of Y with a predictive power of 50.8%, respectively. In both models, low molecular size amino acids with hydrophobic side chains were preferred at the N-terminus, while amino acids with bulky side chains were preferred at the C-terminus for potency. Based on the 5-z model, four Trp (W)-containing antihypertensive dipeptides (IW, LW, VW and AW) were predicted as the most potent renin inhibitors. The peptides were synthesized and in vitro inhibition assay showed that IW and LW inhibited 70% (IC(50), 2.3 mM) and 37% renin activity at 3.2 mM, respectively, whereas VW and AW were inactive. There was no correlation between the observed renin-inhibitory activities and angiotensin-converting enzyme inhibitory activities of the dipeptides. We concluded that the structural similarities between isoleucine and leucine could have contributed to their distinct inhibitory activity when compared to alanine and valine. Therefore, IW may be a useful template for the development of advanced forms of highly active low molecular size antihypertensive peptides and peptidomimetics. PMID:21246225

Udenigwe, Chibuike C; Li, Huan; Aluko, Rotimi E

2012-04-01

104

Effect of sulfuric acid in wood plastic composite  

NASA Astrophysics Data System (ADS)

Wood plastic composite was prepared with simul and MMA in the presence of methanol used as swelling agent at different proportions. Sulfuric acid was incorporated into the impregnating solution to investigate its effect on the polymer loading and tensile strength of the composite. 1% Acid solution induces the highest polymer loading. Effect of additives like NVP, TPGDA and TMPTA was also investigated. Corrosion or leaching effect of the acid on the wood samples was studied. Uptake of the impregnating solution by the samples over a period of time was determined.

Husain, M. M.; Khan, Mubarak A.; Ali, K. M. Idriss; Mustafa, A. I.

1996-01-01

105

Apple juice composition: sugar, nonvolatile acid, and phenolic profiles.  

PubMed

Apples from Michigan, Washington, Argentina, Mexico, and New Zealand were processed into juice; the 8 samples included Golden Delicious, Jonathan, Granny Smith, and McIntosh varieties. Liquid chromatography was used for quantitation of sugars (glucose, fructose, sucrose, and sorbitol), nonvolatile acids (malic, quinic, citric, shikimic, and fumaric), and phenolics (chlorogenic acid and hydroxymethylfurfural [HMF]). Other determinations included pH, 0Brix, and L-malic acid. A number of compositional indices for these authentic juices, e.g., chlorogenic acid content, total malic - L-malic difference, and the HMF:chlorogenic ratio, were at variance with recommended standards. The phenolic profile was shown to be particularly influenced by gelatin fining, with peak areas decreasing by as much as 50%. The L-malic:total malic ratio serves as a better index for presence of synthetic malic acid than does the difference between the 2 determinations. No apparent differences in chemical composition could be attributed to geographic origin. PMID:3417603

Lee, H S; Wrolstad, R E

1988-01-01

106

Analysis of fatty acid content and composition in microalgae.  

PubMed

A method to determine the content and composition of total fatty acids present in microalgae is described. Fatty acids are a major constituent of microalgal biomass. These fatty acids can be present in different acyl-lipid classes. Especially the fatty acids present in triacylglycerol (TAG) are of commercial interest, because they can be used for production of transportation fuels, bulk chemicals, nutraceuticals (?-3 fatty acids), and food commodities. To develop commercial applications, reliable analytical methods for quantification of fatty acid content and composition are needed. Microalgae are single cells surrounded by a rigid cell wall. A fatty acid analysis method should provide sufficient cell disruption to liberate all acyl lipids and the extraction procedure used should be able to extract all acyl lipid classes. With the method presented here all fatty acids present in microalgae can be accurately and reproducibly identified and quantified using small amounts of sample (5 mg) independent of their chain length, degree of unsaturation, or the lipid class they are part of. This method does not provide information about the relative abundance of different lipid classes, but can be extended to separate lipid classes from each other. The method is based on a sequence of mechanical cell disruption, solvent based lipid extraction, transesterification of fatty acids to fatty acid methyl esters (FAMEs), and quantification and identification of FAMEs using gas chromatography (GC-FID). A TAG internal standard (tripentadecanoin) is added prior to the analytical procedure to correct for losses during extraction and incomplete transesterification. PMID:24121679

Breuer, Guido; Evers, Wendy A C; de Vree, Jeroen H; Kleinegris, Dorinde M M; Martens, Dirk E; Wijffels, René H; Lamers, Packo P

2013-01-01

107

Fatty Acid Composition of Bifidobacterium and Lactobacillus Strains  

PubMed Central

Normal C14, C16, and C18 saturated acids and C16 and C18 monoenoic acids are the main fatty acids of nine strains of Bifidobacterium. Their lactobacillic acid content was less than 5%. Lactobacillus strains contained the same fatty acids as main compounds except for octadecanoic acid, which was present only in very low amounts. Eight of nine Lactobacillus strains contained in the stationary phase more than 15% lactobacillic acid. No correlation was observed between the fatty acid composition and other physiological characteristics used in the literature for classification of strains of one genus. Aging of the culture, which involved a decrease of the pH, caused a lengthening of the chain length of the fatty acids of B. bifidum var. pennsylvanicus but only a conversion of octadecenoic to lactobacillic acid in the lactobacilli. Lowering of the temperature of cultivation decreased the chain length of the fatty acids of B. bifidum var. pennsylvanicus. L. lactis did not show any influence of the temperature on the chain length of the fatty acids. The percentage of unsaturated acids was temperature independent in both organisms.

Veerkamp, J. H.

1971-01-01

108

Deoxyribonucleic acid base composition of Micrococcus roseus  

Microsoft Academic Search

The percentage guanine + cytosine (GC) in the DNA of 13 strains ofMicrococcus roseus has been determined. Two methods were used to analyse the base composition, namely determination of Tm value and determination of the ratio E260\\/E280 at pH 3. The percentage GC in the strains ofM. roseus ranged from 66.2 to 73.8 and was in agreement with their present

J. Bohá?ek; M. Kocur; T. Martinec

1969-01-01

109

Polyunsaturated fatty acid saturation by gut lactic acid bacteria affecting host lipid composition.  

PubMed

In the representative gut bacterium Lactobacillus plantarum, we identified genes encoding the enzymes involved in a saturation metabolism of polyunsaturated fatty acids and revealed in detail the metabolic pathway that generates hydroxy fatty acids, oxo fatty acids, conjugated fatty acids, and partially saturated trans-fatty acids as intermediates. Furthermore, we observed these intermediates, especially hydroxy fatty acids, in host organs. Levels of hydroxy fatty acids were much higher in specific pathogen-free mice than in germ-free mice, indicating that these fatty acids are generated through polyunsaturated fatty acids metabolism of gastrointestinal microorganisms. These findings suggested that lipid metabolism by gastrointestinal microbes affects the health of the host by modifying fatty acid composition. PMID:24127592

Kishino, Shigenobu; Takeuchi, Michiki; Park, Si-Bum; Hirata, Akiko; Kitamura, Nahoko; Kunisawa, Jun; Kiyono, Hiroshi; Iwamoto, Ryo; Isobe, Yosuke; Arita, Makoto; Arai, Hiroyuki; Ueda, Kazumitsu; Shima, Jun; Takahashi, Satomi; Yokozeki, Kenzo; Shimizu, Sakayu; Ogawa, Jun

2013-10-29

110

Polyunsaturated fatty acid saturation by gut lactic acid bacteria affecting host lipid composition  

PubMed Central

In the representative gut bacterium Lactobacillus plantarum, we identified genes encoding the enzymes involved in a saturation metabolism of polyunsaturated fatty acids and revealed in detail the metabolic pathway that generates hydroxy fatty acids, oxo fatty acids, conjugated fatty acids, and partially saturated trans-fatty acids as intermediates. Furthermore, we observed these intermediates, especially hydroxy fatty acids, in host organs. Levels of hydroxy fatty acids were much higher in specific pathogen-free mice than in germ-free mice, indicating that these fatty acids are generated through polyunsaturated fatty acids metabolism of gastrointestinal microorganisms. These findings suggested that lipid metabolism by gastrointestinal microbes affects the health of the host by modifying fatty acid composition.

Kishino, Shigenobu; Takeuchi, Michiki; Park, Si-Bum; Hirata, Akiko; Kitamura, Nahoko; Kunisawa, Jun; Kiyono, Hiroshi; Iwamoto, Ryo; Isobe, Yosuke; Arita, Makoto; Arai, Hiroyuki; Ueda, Kazumitsu; Shima, Jun; Takahashi, Satomi; Yokozeki, Kenzo; Shimizu, Sakayu; Ogawa, Jun

2013-01-01

111

Amino acid composition in parenteral nutrition: what is the evidence?  

PubMed Central

Purpose of review Complete parenteral nutrition solutions contain mixed amino acid products providing all nine essential amino acids and a varying composition of nonessential amino acids. Relatively little rigorous comparative efficacy research on altered parenteral nutrition amino acid composition has been published in recent years. Recent findings Limited data from randomized, double-blind, adequately powered clinical trials to define optimal doses of total or individual amino acids in parenteral nutrition are available. An exception is the growing number of studies on the efficacy of glutamine supplementation of parenteral nutrition or given as a single parenteral agent. Parenteral glutamine appears to confer benefit in selected patients; however, additional data to define optimal glutamine dosing and the patient subgroups who may most benefit from this amino acid are needed. Although some promising studies have been published, little data are available in the current era of nutrition support on the clinical efficacy of altered doses of arginine, branched chain amino acids, cysteine, or taurine supplementation of parenteral nutrition. Summary Despite routine use of parenteral nutrition, surprisingly little clinical efficacy data are available to guide total or specific amino acid dosing in adult and pediatric patients requiring this therapy. This warrants increased attention by the research community and funding agencies to better define optimal amino acid administration strategies in patient subgroups requiring parenteral nutrition.

Yarandi, Shadi S.; Zhao, Vivian M.; Hebbar, Gautam; Ziegler, Thomas R.

2011-01-01

112

U373MG cells express PepT2 and accumulate the fluorescently tagged dipeptide-derivative ?-Ala-Lys-N ?-AMCA  

Microsoft Academic Search

Aim of this study was to examine the dipeptide transport of ?-Ala-Lys-N?-AMCA in the human glioma cell line U373-MG and its potential regulation by diverse hormones and culture media. A mixed glial primary cell culture of the newborn rat served as reference cell system. ?-Ala-Lys-N?-AMCA (?-Ala-Lys-N?-7-amino-4-methyl-coumarin-3-acetic acid) is a highly specific reporter substrate to investigate the dipeptide transport system PepT2.

Mathias Zimmermann; Kai Kappert; Alexandru Constantin Stan

2010-01-01

113

Analogues of both Leu- and Met-enkephalin containing a constrained dipeptide isostere prepared from a Baylis-Hillman adduct.  

PubMed

An efficient route was developed for the synthesis of the Fmoc-protected dipeptide 4, isostere of Gly-Gly containing an alpha-methylene beta-amino acid; the conformationally restricted analogues of Leu-enkephalin, 3a, and Met-enkephalin, 3b, respectively, were prepared by changing 4 for Gly(2)-Gly(3) in the native compounds 3a and 3b whose biological activities were significantly lower than the parent compounds. PMID:19585218

Galeazzi, Roberta; Martelli, Gianluca; Marcucci, Eleonora; Orena, Mario; Rinaldi, Samuele; Lattanzi, Roberta; Negri, Lucia

2010-04-01

114

A note on the amino acid composition of the turkey.  

PubMed

1. The amino acid composition of the whole body protein of 28- and 56-day-old turkeys is reported. 2. There were some differences between the two ages; these could largely be reconciled by considering the likely differences in the proportion of feather protein. 3. The results were compared with similar values for the chicken and goose; overall there is a striking similarity, both in absolute concentrations and relative proportions of amino acids. PMID:7104783

Fisher, C; Scougall, R K

1982-05-01

115

Bile acid composition of rainbow trout, Salmo gairdneri  

Microsoft Academic Search

The bile acid composition and metabolism of rainbow troutSalmo gairdneri has been investigated by thin layer chromatography, gas liquid chromatography, and radio gas liquid chromatography methods.\\u000a For this purpose gallbladder bile was collected from fed fish at 6 and 13 months and from starved fish at 12 months of age.\\u000a Cholic acid was found to be the main component and

J. E. Denton; M. K. Yousef; I. M. Yousef; A. Kuksis

1974-01-01

116

Discriminating bioluminescent proteins by incorporating average chemical shift and evolutionary information into the general form of Chou's pseudo amino acid composition.  

PubMed

Bioluminescent proteins are highly sensitive optical reporters for imaging in live animals; they have been extensively used in analytical applications in intracellular monitoring, genetic regulation and detection, and immune and binding assays. In this work, we systematically analyzed the sequence and structure information of 199 bioluminescent and nonbioluminescent proteins, respectively. Based on the results, we presented a novel method called auto covariance of averaged chemical shift (acACS) for extracting structure features from a sequence. A classifier of support vector machine (SVM) fusing increment of diversity (ID) was used to distinguish bioluminescent proteins from nonbioluminescent proteins by combining dipeptide composition, reduced amino acid composition, evolutionary information, and acACS. The overall prediction accuracy evaluated by jackknife validation reached 82.16%. This result was better than that obtained by other existing methods. Improvement of the overall prediction accuracy reached up to 5.33% higher than those of the SVM and auto covariance of sequential evolution information by 10-fold cross-validation. The acACS algorithm also outperformed other feature extraction methods, indicating that our approach is better than other existing methods in the literature. PMID:23770403

Fan, Guo-Liang; Li, Qian-Zhong

2013-10-01

117

Fatty acid composition of wild anthropoid primate milks.  

PubMed

Fatty acids in milk reflect the interplay between species-specific physiological mechanisms and maternal diet. Anthropoid primates (apes, Old and New World monkeys) vary in patterns of growth and development and dietary strategies. Milk fatty acid profiles also are predicted to vary widely. This study investigates milk fatty acid composition of five wild anthropoids (Alouatta palliata, Callithrix jacchus, Gorilla beringei beringei, Leontopithecus rosalia, Macaca sinica) to test the null hypothesis of a generalized anthropoid milk fatty acid composition. Milk from New and Old World monkeys had significantly more 8:0 and 10:0 than milk from apes. The leaf eating species G. b. beringei and A. paliatta had a significantly higher proportion of milk 18:3n-3, a fatty acid found primarily in plant lipids. Mean percent composition of 22:6n-3 was significantly different among monkeys and apes, but was similar to the lowest reported values for human milk. Mountain gorillas were unique among anthropoids in the high proportion of milk 20:4n-6. This seems to be unrelated to requirements of a larger brain and may instead reflect species-specific metabolic processes or an unknown source of this fatty acid in the mountain gorilla diet. PMID:17916436

Milligan, Lauren A; Rapoport, Stanley I; Cranfield, Michael R; Dittus, Wolfgang; Glander, Kenneth E; Oftedal, Olav T; Power, Michael L; Whittier, Christopher A; Bazinet, Richard P

2008-01-01

118

Proximate, amino acid, fatty acid and mineral composition of raw and cooked camel (Camelus dromedarius) meat  

Microsoft Academic Search

Purpose – The purpose of the paper is to study the effects of cooking on proximate composition, amino acids, fatty acids, minerals and total, heme and non-heme iron content of camel meat. Design\\/methodology\\/approach – A total of ten longissimus thoracis muscles (500 grams) were collected between the tenth and twelfth ribs of the left side. Samples were randomly collected from

I. T. Kadim; M. R. Al-Ani; R. S. Al-Maqbaly; M. H. Mansour; O. Mahgoub; E. H. Johnson

2011-01-01

119

An Index to Deoxyribonucleic Acid Base Compositions of Bacterial Species  

Microsoft Academic Search

SUMMARY This paper consists of a reference list of bacterial species for which deoxyribonucleic acid base compositions are known. Culture-collection strain numbers have been included wherever possible. The compilation may also provide a basis for the inclusion of these data into species descriptions. the authors are given in parenthesis. The only exceptions are: 'Diplococcus' is included in Streptococcus; ' Coxiella'

L. R. Hill

1966-01-01

120

Oleuropein on lipid and fatty acid composition of rat heart  

Microsoft Academic Search

Male rats of the Wistar strain were given oleuropein for 3 weeks at a dose of 25 or 50 mg\\/kg of body weight. Heart samples were analyzed for the lipid composition by the Iatroscan TLCFID technique and for the fatty acid profile of neutral and polar lipids by the capillary gas chromatography. In addition, the oleuropein, ?- and ?-tocopherol content

Valentina Ruíz-Gutiérrez; Francisco J. G. Muriana; Roberto Maestro; Enrique Graciani

1995-01-01

121

Conjugated linoleic acid: health implications and effects on body composition  

Microsoft Academic Search

Conjugated linoleic acid (CLA) is attracting interest because of its purported effects on body composition, specifically a reduction in body fat mass and an increase in lean body mass. Other reported beneficial health-related effects of CLA include anticarcinogenic, antiatherogenic, antidiabetogenic, and immune modulating properties. Because research on CLA has been almost exclusively in animals and the mechanism(s) by which CLA

Lisa Rainer; Cynthia J. Heiss

2004-01-01

122

Corrosion of graphite composites in phosphoric acid fuel cells  

NASA Technical Reports Server (NTRS)

Polymers, polymer-graphite composites and different carbon materials are being considered for many of the fuel cell stack components. Exposure to concentrated phosphoric acid in the fuel cell environment and to high anodic potential results in corrosion. Relative corrosion rates of these materials, failure modes, plausible mechanisms of corrosion and methods for improvement of these materials are investigated.

Christner, L. G.; Dhar, H. P.; Farooque, M.; Kush, A. K.

1986-01-01

123

Fatty acid and carotenoid composition of Rhodotorula strains.  

PubMed

Lipid content and composition of fatty acids with 6-25 carbon atoms were studied on strains of the 13 pink or red yeast species belonging to the genus Rhodotorula. The total amount of lipid represented an average of 13% of the dry weight. The neutral and polar lipid fractions were analyzed separately. For all the strains studied, the major fatty acids in both fractions were oleic, linoleic and palmitic acids, which formed 80% of the total number of fatty acids. A notable amount of arachidonic acid, a precursor of eicosanoid hormones, was found in R. acheniorum, R. aurantiaca and R. bacarum. Depending on the strain, 1-10 carotenoid pigments were detected; beta-carotene was always the major carotenoid present. PMID:7668929

Perrier, V; Dubreucq, E; Galzy, P

1995-09-01

124

Modification of fetal plasma amino acid composition by placental amino acid exchangers in vitro  

PubMed Central

Fetal growth is dependent on both the quantity and relative composition of amino acids delivered to the fetal circulation, and impaired placental amino acid supply is associated with restricted fetal growth. Amino acid exchangers can alter the composition, but not the quantity, of amino acids in the intra- and extracellular amino acid pools. In the placenta, exchangers may be important determinants of the amino acid composition in the fetal circulation. This study investigates the substrate specificity of exchange between the placenta and the feto-placental circulation. Maternal–fetal transfer of radiolabelled amino acids and creatinine were measured in the isolated perfused human placental cotyledon. Transfer of l-[14C]serine or l-[14C]leucine, and [3H]glycine, were measured in the absence of amino acids in the fetal circulation (transfer by non-exchange mechanisms) and following 10–20 ?mol boluses of unlabelled amino acids into the fetal circulation to provide substrates for exchange (transfer by exchange and non-exchange mechanisms). The ability of fetal arterial boluses of l-alanine and l-leucine to stimulate release of amino acids from the placenta was also determined using HPLC in order to demonstrate the overall pattern of amino acid release. Experiments with radiolabelled amino acids demonstrated increased maternal–fetal transfer of l-serine and l-leucine, but not glycine, following boluses of specific amino acids into the fetal circulation. l-[14C]Leucine, but not l-[14C]serine or [3H]glycine, was transferred from the maternal to the fetal circulation by non-exchange mechanisms also (P < 0.01). HPLC analysis demonstrated that fetal amino acid boluses stimulated increased transport of a range of different amino acids by 4–7 ?mol l?1 (P < 0.05). Amino acid exchange provides a mechanism to supply the fetus with amino acids that it requires for fetal growth. This study demonstrates that these transporters have the capacity to exchange micromolar amounts of specific amino acids, and suggests that they play an important role in regulating fetal plasma amino acid composition.

Cleal, Jane K; Brownbill, Paul; Godfrey, Keith M; Jackson, John M; Jackson, Alan A; Sibley, Colin P; Hanson, Mark A; Lewis, Rohan M

2007-01-01

125

Tissue fatty acid composition in human urothelial carcinoma.  

PubMed

Bladder cancer cells appear to have an altered lipid metabolism as evidenced by modulated lipogenic enzymes. The aim of this study is to investigate differences in tissue fat composition between malignant and adjacent normal urinary bladder tissue. Normal-appearing and malignant bladder tissues were collected from 31 patients with high-grade (Ta) urothelial carcinoma during transurethral resection (TUR). The fatty acid composition in the tissue was determined by gas liquid chromatography. In the bladder cancer tissue, levels of stearic acid (18:0; P = 0.01) and oleic acid (18:1n-9; P = 0.03) were higher, and the level of arachidonic aid (20:4n-6; P < 0.001) was lower than that in the normal-appearing bladder. Overall, bladder cancer tissue showed a significant reduction in total n-6 polyunsaturated fatty acid (-15.1%; P < 0.001). The change in the fatty acid composition may be regarded as an indicator of altered lipid metabolism occurring in vivo during human bladder tumourigenesis. PMID:23617090

Miryaghoubzadeh, J; Darabi, M; Madaen, K; Shaaker, M; Mehdizadeh, A; Hajihosseini, R

2013-01-01

126

Perfluoroalkyl Acid contamination and polyunsaturated Fatty Acid composition of French freshwater and marine fishes.  

PubMed

In this study, French marine and freshwater fish perfluoroalkyl acid (PFAA) contamination are presented along with their fatty acid (FA) composition to provide further elements for a risk/benefit balance of fish consumption to be assessed. The 29 most consumed marine fish species were collected in four metropolitan French coastal areas in 2004 to constitute composite samples. Geographical differences in terms of consumed species and contamination level were taken into account. Three hundred and eighty-seven composite samples corresponding to 16 freshwater fish species collected between 2008 and 2010 in the six major French rivers or their tributaries were selected among the French national agency for water and aquatic environments freshwater fish sample library. The raw edible parts were analyzed for FA composition and PFAA contamination. Results show that freshwater fishes are more contaminated by PFAAs than marine fishes and do not share the same contamination profile. Freshwater fish contamination is mostly driven by perfluorooctane sulfonate (PFOS) (75%), whereas marine fish contamination is split between perfluorooctanoic acid (PFOA) (24%), PFOS (20%), perfluorohexanoic acid (PFHxA) (15%), perfluoropentanoic acid (PFHpA) (11%), and perfluorobutanoic acid (PFBA) (11%). Common carp, pike-perch, European perch, thicklip grey mullet, and common roach presented the most unfavorable balance profile due to their high level of PFAAs and low level of n-3 long-chain polyunsaturated fatty acids (LC-PUFAs). These data could be used, if needed, in an updated opinion on fish consumption that takes into account PFAA contamination. PMID:25004121

Yamada, Ami; Bemrah, Nawel; Veyrand, Bruno; Pollono, Charles; Merlo, Mathilde; Desvignes, Virginie; Sirot, Véronique; Oseredczuk, Marine; Marchand, Philippe; Cariou, Ronan; Antignac, Jean-Phillippe; Le Bizec, Bruno; Leblanc, Jean-Charles

2014-07-30

127

Effect of Dipeptides on In vitro Maturation, Fertilization and Subsequent Embryonic Development of Porcine Oocytes  

PubMed Central

The effects of amino acids and dipeptides on in vitro production of porcine embryos and accumulation of ammonia in culture medium during developmental stages were examined in this study. The maturation, fertilization and development of embryonic cultures were performed in modified Tissue culture medium (mTCM)-199 supplemented with 10% (v/v) porcine follicular fluid, modified Tyrode’s albumin lactate pyruvate (mTALP) medium, and modified North Carolina State University (mNCSU)-23 medium, respectively. In addition, amino acids and dipeptides of different concentrations and combinations were used to treat the embryos. The addition of L-alanyl-L-glutamine (AlnGln)+L-glycyl-L-glutamine (GlyGln) significantly (p<0.05) improved oocyte maturation, fertilization and the incorporation and oxidation of 14C(U)-glucose when compared to the control group and other treatment groups. Additionally, 2–4 cell, 8–16 cell, morula and blastocyst development increased significantly (p<0.05) following treatment with AlnGln+GlyGln when compared to the control group and other treatment groups, while this treatment reduced the accumulation of ammonia. Taken together, these findings suggest that treatment with AlnGln+GlyGln may play an important role in increasing the rate of porcine oocyte maturation, fertilization and embryonic development by reducing the level of accumulated ammonia measured in the culture media.

Tareq, K. M. A.; Akter, Quzi Sharmin; Tsujii, Hirotada; Khandoker, M. A. M. Yahia; Choi, Inho

2013-01-01

128

Biotechnological Process for Production of ?-Dipeptides from Cyanophycin on a Technical Scale and Its Optimization ?  

PubMed Central

A triphasic process was developed for the production of ? dipeptides from cyanophycin (CGP) on a large scale. Phase I comprises an optimized acid extraction method for technical isolation of CGP from biomass. It yielded highly purified CGP consisting of aspartate, arginine, and a little lysine. Phase II comprises the fermentative production of an extracellular CGPase (CphEal) from Pseudomonas alcaligenes strain DIP1 on a 500-liter scale in mineral salts medium, with citrate as the sole carbon source and CGP as an inductor. During optimization, it was shown that 2 g liter?1 citrate, pH 6.5, and 37°C are ideal parameters for CphEal production. Maximum enzyme yields were obtained after induction in the presence of 50 mg liter?1 CGP or CGP dipeptides for 5 or 3 h, respectively. Aspartate at a concentration of 4 g liter?1 induced CphEal production with only about 30% efficiency in comparison to that with CGP. CphEal was purified utilizing its affinity for the substrate and its specific binding to CGP. CphEal turned out to be a serine protease with maximum activity at 50°C and at pH 7 to 8.5. Phase III comprises degradation of CGP to ?-aspartate-arginine and ?-aspartate-lysine dipeptides with a purity of over 99% (by thin-layer chromatography and high-performance liquid chromatography), employing a crude CphEal preparation. Optimum degradation parameters were 100 g liter?1 CGP, 10 g liter?1 crude CphEal powder, and 4 h of incubation at 50°C. The overall efficiency of phase III was 91%, while 78% (wt/wt) of the used CphEal powder with sustained activity toward CGP was recovered. The optimized process was performed with industrial materials and equipment and is applicable to any desired scale.

Sallam, Ahmed; Kast, Alene; Przybilla, Simon; Meiswinkel, Tobias; Steinbuchel, Alexander

2009-01-01

129

Engineered polymer nanoparticles containing hydrophobic dipeptide for inhibition of amyloid-? fibrillation.  

PubMed

Protein aggregation into amyloid fibrils is implicated in the pathogenesis of many neurodegenerative diseases. Engineered nanoparticles have emerged as a potential approach to alter the kinetics of protein fibrillation process. Yet, there are only a few reports describing the use of nanoparticles for inhibition of amyloid-? 40 (A?(40)) peptide aggregation, involved in Alzheimer's disease (AD). In the present study, we designed new uniform biocompatible amino-acid-based polymer nanoparticles containing hydrophobic dipeptides in the polymer side chains. The dipeptide residues were designed similarly to the hydrophobic core sequence of A?. Poly(N-acryloyl-L-phenylalanyl-L-phenylalanine methyl ester) (polyA-FF-ME) nanoparticles of 57 ± 6 nm were synthesized by dispersion polymerization of the monomer A-FF-ME in 2-methoxy ethanol, followed by precipitation of the obtained polymer in aqueous solution. Cell viability assay confirmed that no significant cytotoxic effect of the polyA-FF-ME nanoparticles on different human cell lines, e.g., PC-12 and SH-SY5Y, was observed. A significantly slow secondary structure transition from random coil to ?-sheets during A?(40) fibril formation was observed in the presence of these nanoparticles, resulting in significant inhibition of A?(40) fibrillation kinetics. However, the polyA-FF-ME analogous nanoparticles containing the L-alanyl-L-alanine (AA) dipeptide in the polymer side groups, polyA-AA-ME nanoparticles, accelerate the A?(40) fibrillation kinetics. The polyA-FF-ME nanoparticles and the polyA-AA-ME nanoparticles may therefore contribute to a mechanistic understanding of the fibrillation process, leading to the development of therapeutic strategies against amyloid-related diseases. PMID:22897679

Skaat, Hadas; Chen, Ravit; Grinberg, Igor; Margel, Shlomo

2012-09-10

130

Deoxyribonucleic Acid Base Composition of Some Members of the Micrococcaceae  

PubMed Central

Auletta, Angela E. (Catholic University, Washington, D.C.), and E. R. Kennedy. Deoxyribonucleic acid base composition of some members of the Micrococcaceae. J. Bacteriol. 92:28–34. 1966.—Thirty-seven strains from the genera Micrococcus, Staphylococcus, Gaffkya, and Sarcina were examined for deoxyribonucleic acid base composition and biochemical activity. Organisms were tested for production of catalase, coagulase, deoxyribonuclease, oxidase, phosphatase, hydrogen sulfide, indole, and acetoin; nitrate reduction; gelatin, starch, and urea hydrolysis; citrate and ammonium phosphate utilization; NaCl tolerance; growth at 10 and 45 C, and growth in litmus milk. They were tested for production of acid from dextrose and mannitol under anaerobic conditions, and for aerobic production of acid from dextrose, mannitol, lactose, sucrose, raffinose, maltose, xylose, and glycerol. Organisms could be divided into two groups on the basis of guanine-cytosine (GC) content. Group I had an average GC content of 32%, and included all organisms which produced acid from dextrose. Group II had an average GC content of 62%, and included those organisms incapable of producing acid from dextrose under anaerobic conditions. Sarcina ureae had a GC content of 43%.

Auletta, Angela E.; Kennedy, E. R.

1966-01-01

131

Self-assembly of azide containing dipeptides.  

PubMed

Functional structures and materials are formed spontaneously in nature through the process of self-assembly. Mimicking this process in vitro will lead to the formation of new substances that would impact many areas including energy production and storage, biomaterials and implants, and drug delivery. The considerable structural diversity of peptides makes them appealing building blocks for self-assembly in vitro. This paper describes the self-assembly of three aromatic dipeptides containing an azide moiety: H-Phe(4-azido)-Phe(4-azido)-OH, H-Phe(4-azido)-Phe-OH, and H-Phe-Phe(4-azido)-OH. The peptide H-Phe(4-azido)-Phe(4-azido)-OH self-assembled into porous spherical structures, whereas the peptides H-Phe(4-azido)-Phe-OH and H-Phe-Phe(4-azido)-OH did not form any ordered structures under the examined experimental conditions. The azido group of the peptide can serve as a photo cross-linking agent upon irradiation with UV light. To examine the effect of this group and its activity on the self-assembled structures, we irradiated the assemblies in solution for different time periods. Using electron microscopy, we determined that the porous spherical assemblies formed by the peptide H-Phe(4-azido)-Phe(4-azido)-OH underwent a structural change upon irradiation. In addition, using FT-IR, we detected the chemical change of the peptide azido group. Moreover, using indentation experiments with atomic force microscopy, we showed that the Young's modulus of the spherical assemblies increased after 20?min of irradiation with UV light. Overall, irradiating the solution of the peptide assemblies containing the azido group resulted in a change both in the morphology and mechanical properties of the peptide-based structures. These ordered assemblies or their peptide monomer building blocks can potentially be incorporated into other peptide assemblies to generate stiffer and more stable materials. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd. PMID:24889029

Yuran, Sivan; Razvag, Yair; Das, Priyadip; Reches, Meital

2014-07-01

132

Fatty acid composition of fat depots in wintering Canada geese  

USGS Publications Warehouse

I determined the fatty acid composition of subcutaneous, abdominal, visceral, and leg saddle depots in adult female Canada Geese (Branta canadensis) wintering in north-central Missouri during October 1984-March 1985. Mean levels of C14:0, C16:0, C16:1, C18:0, C18:1, C18:2, and C18:3 generally were highest in the subcutaneous and abdominal depots. The ratio of saturated to unsaturated fats was highest in the leg saddle depot and lowest in the abdominal depot. I also assessed the differences among sexes, seasons, and years in fatty acid composition of abdominal fat depots in adult geese collected during October-March, 1985-1987. Adult females had consistently higher levels of C14:0 in abdominal depots than males. Fatty acid composition of the abdominal depot differed among years but not by season. In the abdominal depot, C14:0, C16:0, C16:1, and C18:1 were higher in 1986-1987 compared with the previous two years, whereas C18:3 was highest in 1984-1985. Differences among years reflected changes in winter diet. Fatty acids of wintering geese were similar to those previously found in breeding Canada Geese.

Austin, J. E.

1993-01-01

133

Polypeptide Amino Acid Composition and Isoelectric Point II. Comparison between Experiment and Theory  

Microsoft Academic Search

Experimental isoelectric points and amino acid compositional data for 58 proteins were compiled and organized. The experimental isoelectric points correlated well with the acidic to basic amino acid molar ratio. This agreement proved the usefulness of a recently presented analytical expression correlating explicitly protein isoelectric point to acid-base composition. Regressed acidic and basic dissociation constants were determined to be pKa

C. S. Patrickios; E. N. Yamasaki

1995-01-01

134

Effects of fasting on bile acid metabolism and and biliary lipid composition in man  

Microsoft Academic Search

The effects of a four to six day fast on gall- bladder bile lipid composition, bile acid pool size, bile acid composition, and cholic acid metabolism have been determined in normal human subjects. Total bile acid pool size and cholic acid poor size were measured before and after fasting by a one-sample technique previously validated in our laboratory. The rate

William C. Duane; Ronald L. Ginsberg; Lynn J. Bennion

135

Beta-aminopeptidase-catalyzed biotransformations of beta(2)-dipeptides: kinetic resolution and enzymatic coupling.  

PubMed

We have previously shown that the beta-aminopeptidases BapA from Sphingosinicella xenopeptidilytica and DmpA from Ochrobactrum anthropi can catalyze reactions with non-natural beta(3)-peptides and beta(3)-amino acid amides. Here we report that these exceptional enzymes are also able to utilize synthetic dipeptides with N-terminal beta(2)-amino acid residues as substrates under aqueous conditions. The suitability of a beta(2)-peptide as a substrate for BapA or DmpA was strongly dependent on the size of the C(alpha) substituent of the N-terminal beta(2)-amino acid. BapA was shown to convert a diastereomeric mixture of the beta(2)-peptide H-beta(2)hPhe-beta(2)hAla-OH, but did not act on diastereomerically pure beta(2),beta(3)-dipeptides containing an N-terminal beta(2)-homoalanine. In contrast, DmpA was only active with the latter dipeptides as substrates. BapA-catalyzed transformation of the diastereomeric mixture of H-beta(2)hPhe-beta(2)hAla-OH proceeded along two highly S-enantioselective reaction routes, one leading to substrate hydrolysis and the other to the synthesis of coupling products. The synthetic route predominated even at neutral pH. A rise in pH of three log units shifted the synthesis-to-hydrolysis ratio (v(S)/v(H)) further towards peptide formation. Because the equilibrium of the reaction lies on the side of hydrolysis, prolonged incubation resulted in the cleavage of all peptides that carried an N-terminal beta-amino acid of S configuration. After completion of the enzymatic reaction, only the S enantiomer of beta(2)-homophenylalanine was detected (ee>99 % for H-(S)-beta(2)-hPhe-OH, E>500); this confirmed the high enantioselectivity of the reaction. Our findings suggest interesting new applications of the enzymes BapA and DmpA for the production of enantiopure beta(2)-amino acids and the enantioselective coupling of N-terminal beta(2)-amino acids to peptides. PMID:20340152

Heck, Tobias; Reimer, Artur; Seebach, Dieter; Gardiner, James; Deniau, Gildas; Lukaszuk, Aneta; Kohler, Hans-Peter E; Geueke, Birgit

2010-05-17

136

Prebiotically plausible mechanisms increase compositional diversity of nucleic acid sequences  

PubMed Central

During the origin of life, the biological information of nucleic acid polymers must have increased to encode functional molecules (the RNA world). Ribozymes tend to be compositionally unbiased, as is the vast majority of possible sequence space. However, ribonucleotides vary greatly in synthetic yield, reactivity and degradation rate, and their non-enzymatic polymerization results in compositionally biased sequences. While natural selection could lead to complex sequences, molecules with some activity are required to begin this process. Was the emergence of compositionally diverse sequences a matter of chance, or could prebiotically plausible reactions counter chemical biases to increase the probability of finding a ribozyme? Our in silico simulations using a two-letter alphabet show that template-directed ligation and high concatenation rates counter compositional bias and shift the pool toward longer sequences, permitting greater exploration of sequence space and stable folding. We verified experimentally that unbiased DNA sequences are more efficient templates for ligation, thus increasing the compositional diversity of the pool. Our work suggests that prebiotically plausible chemical mechanisms of nucleic acid polymerization and ligation could predispose toward a diverse pool of longer, potentially structured molecules. Such mechanisms could have set the stage for the appearance of functional activity very early in the emergence of life.

Derr, Julien; Manapat, Michael L.; Rajamani, Sudha; Leu, Kevin; Xulvi-Brunet, Ramon; Joseph, Isaac; Nowak, Martin A.; Chen, Irene A.

2012-01-01

137

Prebiotically plausible mechanisms increase compositional diversity of nucleic acid sequences.  

PubMed

During the origin of life, the biological information of nucleic acid polymers must have increased to encode functional molecules (the RNA world). Ribozymes tend to be compositionally unbiased, as is the vast majority of possible sequence space. However, ribonucleotides vary greatly in synthetic yield, reactivity and degradation rate, and their non-enzymatic polymerization results in compositionally biased sequences. While natural selection could lead to complex sequences, molecules with some activity are required to begin this process. Was the emergence of compositionally diverse sequences a matter of chance, or could prebiotically plausible reactions counter chemical biases to increase the probability of finding a ribozyme? Our in silico simulations using a two-letter alphabet show that template-directed ligation and high concatenation rates counter compositional bias and shift the pool toward longer sequences, permitting greater exploration of sequence space and stable folding. We verified experimentally that unbiased DNA sequences are more efficient templates for ligation, thus increasing the compositional diversity of the pool. Our work suggests that prebiotically plausible chemical mechanisms of nucleic acid polymerization and ligation could predispose toward a diverse pool of longer, potentially structured molecules. Such mechanisms could have set the stage for the appearance of functional activity very early in the emergence of life. PMID:22319215

Derr, Julien; Manapat, Michael L; Rajamani, Sudha; Leu, Kevin; Xulvi-Brunet, Ramon; Joseph, Isaac; Nowak, Martin A; Chen, Irene A

2012-05-01

138

Cultural Characteristics and Fatty Acid Composition of Corynebacterium acnes  

PubMed Central

A detailed study of the cultural characteristics and cellular fatty acid composition of 27 isolates of Corynebacterium acnes was performed to establish the properties by which this organism may be identified and characterized. The fatty acids were extracted directly from whole cells and examined as methyl esters by gas-liquid chromatography. Each strain possessed a similar fatty acid profile which was characterized by a large percentage of C15 branched-chain acid. Uniformity in certain biochemical reactions and cultural characteristics was also observed. All strains were catalase-positive, nonmotile, and urease-negative, reduced nitrate, liquefied gelatin, failed to hydrolyze esculin and starch, and gave a positive methyl red test. Glucose, fructose, and glycerol were fermented, but not lactose, salicin, sucrose, maltose, xylose, or arabinose. Production of hydrogen sulfide and indole, fermentation of mannitol, and hemolytic activity were variable characteristics. Two species of the genus Propionibacterium were also tested and found to be similar to C. acnes both in cultural characteristics and fatty acid composition. The results strengthen previous suggestions that C. acnes should be classified in the genus Propionibacterium.

Moss, C. Wayne; Dowell, V. R.; Lewis, V. J.; Schekter, M. A.

1967-01-01

139

Fatty acid profile of fish following a change in dietary fatty acid source: model of fatty acid composition with a dilution hypothesis  

Microsoft Academic Search

The fatty acid (FA) content of fish is generally said to reflect fatty acid composition of the diet. In fact, incorporation of FA into tissues is modulated by various metabolic factors, and final composition will depend upon the initial FA content, cumulative intake of dietary fatty acids, growth rate and duration. Analysis of time course of changes in FA composition

J. H. Robin; C. Regost; J. Arzel; S. J Kaushik

2003-01-01

140

Fatty acid composition of some medicinally useful seeds.  

PubMed

Fatty acid composition of seeds from the fruits of Butea monosperma, Jatropha glandulifera and Portulaca oleracea of three different families, namely Papilionaceae, Euphorbiaceae and Portulaceae were determined through Gas Liquid Chromatography to find novel natural sources of essential fatty acids for human health and of economic interest. Comparative studies were also performed to ascertain the utilization of each species for domestic as well as industrial purpose and the quality parameters developed can be utilized as marker characters for the aforesaid seeds used by the pharmaceutical industries. PMID:17135159

Srivastava, Manjoosha; Banerji, Ranjan; Rawat, A K S; Mehrotra, Shanta

2006-01-01

141

Genetic Regulation of Unsaturated Fatty Acid Composition in C. elegans  

Microsoft Academic Search

Delta-9 desaturases, also known as stearoyl-CoA desaturases, are lipogenic enzymes responsible for the generation of vital components of membranes and energy storage molecules. We have identified a novel nuclear hormone receptor, NHR-80, that regulates delta-9 desaturase gene expression in Caenorhabditis elegans. Here we describe fatty acid compositions, lifespans, and gene expression studies of strains carrying mutations in nhr-80 and in

Trisha J Brock; John Browse; Jennifer L Watts

2006-01-01

142

A note on the amino acid composition of the Turkey  

Microsoft Academic Search

1. The amino acid composition of the whole body protein of 28? and 56?d?old turkeys is reported.2. There were some differences between the two ages; these could largely be reconciled by considering the likely differences in the proportion of feather protein.3. The results were compared with similar values for the chicken and goose; overall there is a striking similarity, both

C. Fisher; R. K. Scougall

1982-01-01

143

Synthesis and binding studies of two new macrocyclic receptors for the stereoselective recognition of dipeptides  

PubMed Central

Summary We present here the design, synthesis, and analysis of a series of receptors for peptide ligands inspired by the hydrogen-bonding pattern of protein ?-sheets. The receptors themselves can be regarded as strands 1 and 3 of a three-stranded ?-sheet, with cross-linking between the chains through the 4-position of adjacent phenylalanine residues. We also report on the conformational equilibria of these receptors in solution as well as on their tendency to dimerize. 1H NMR titration experiments are used to quantify the dimerization constants, as well as the association constant values of the 1:1 complexes formed between the receptors and a series of diamides and dipeptides. The receptors show moderate levels of selectivity in the molecular recognition of the hydrogen-bonding pattern present in the diamide series, selecting the ?-amino acid-related hydrogen-bonding functionality. Only one of the two cyclic receptors shows modest signs of enantioselectivity and moderate diastereoselectivity in the recognition of the enantiomers and diastereoisomers of the Ala-Ala dipeptide (??G 0 1 (DD-DL) = ?1.08 kcal/mol and ??G 0 1 (DD-LD) = ?0.89 kcal/mol). Surprisingly, the linear synthetic precursors show higher levels of stereoselectivity than their cyclic counterparts.

Castilla, Ana Maria; Morgan Conn, M

2010-01-01

144

Analysing the substrate multispecificity of a proton-coupled oligopeptide transporter using a dipeptide library  

PubMed Central

Peptide uptake systems that involve members of the proton-coupled oligopeptide transporter (POT) family are conserved across all organisms. POT proteins have characteristic substrate multispecificity, with which one transporter can recognize as many as 8,400 types of di/tripeptides and certain peptide-like drugs. Here we characterize the substrate multispecificity of Ptr2p, a major peptide transporter of Saccharomyces cerevisiae, using a dipeptide library. The affinities (Ki) of di/tripeptides toward Ptr2p show a wide distribution range from 48?mM to 0.020?mM. This substrate multispecificity indicates that POT family members have an important role in the preferential uptake of vital amino acids. In addition, we successfully establish high performance ligand affinity prediction models (97% accuracy) using our comprehensive dipeptide screening data in conjunction with simple property indices for describing ligand molecules. Our results provide an important clue to the development of highly absorbable peptides and their derivatives including peptide-like drugs.

Ito, Keisuke; Hikida, Aya; Kawai, Shun; Lan, Vu Thi Tuyet; Motoyama, Takayasu; Kitagawa, Sayuri; Yoshikawa, Yuko; Kato, Ryuji; Kawarasaki, Yasuaki

2013-01-01

145

The effect of conjugated linoleic acid on plasma lipoproteins and tissue fatty acid composition in humans  

Microsoft Academic Search

Conjugated linoleic acid (CLA) has been suggested by some animal studies to possess antiatherogenic properties. To determine,\\u000a in humans, the effect of dietary CLA on blood lipids, lipoproteins, and tissue fatty acid composition, we conducted a 93-d\\u000a study with 17 healthy female volunteers at the Metabolic Research Unit of the Western Human Nutrition Research Center. Throughout\\u000a the study, subjects were

P. Benito; G. J. Nelson; D. S. Kelley; G. Bartolini; P. C. Schmidt; V. Simon

2001-01-01

146

Amino Acid Composition-Dependent Elasticity of SPIDER Silk  

NASA Astrophysics Data System (ADS)

Spider silk exhibits excellent mechanical features in both toughness and extensibility. In recent years considerable investigations have focused on it. The understanding of spider silk protein is important for the development bionic silk. In this paper, we study by Monte Carlo simulation the force-of-extension property of spider silk proteins as a function of the residue composition for major and minor ampullate glands of typical Araneid orb weaver as well as that for one artificial spider silk. The results are also compared with those from a designed protein whose amino acid composition is uniform. The results clearly show that the major and minor ampullate gland proteins are much tougher than the designed protein, whereas the artificial protein, as a model of a nature spider silk, does have good mechanical properties. Our simulation reveals that mechanical property of a spider silk protein is dependent on its amino acid composition and that an excellent result of natural evolution is manifest in the composition of the spider silk protein.

Zhang, Yong; Dai, Luru; Ou-Yang, Zhong-Can

147

Comparison of the fatty acid compositions in intraepithelial and infiltrating lesions of the cervix: part I, total fatty acid profiles  

Microsoft Academic Search

In the first part of this study, the possible role of essential total fatty acids and their metabolites during cervical carcinogenesis was investigated. Since membrane lipids play a key role in cell proliferation and differentiation, disturbances in the fatty acid compositions of cell membranes and the modulation of membrane fatty acid compositions received attention in several in vitro studies. There

L. Louw; A. M. Engelbrecht; F. Cloete

1998-01-01

148

Formulated nucleic acid compositions and methods of administering the same for gene therapy  

US Patent & Trademark Office Database

Compositions and methods for administering nucleic acid compositions in vitro to cells in culture or in vivo to an organism whereby the uptake of nucleic acids is enhanced are provided. Various compositions, including those incorporating protective, interactive, non-condensing compounds, are utilized to protect and administered nucleic acid formulation, thereby prolonging the localized bioavailability of the administered nucleic acid and enhancing expression from the nucleic acid.

2003-02-04

149

Postnatal changes in fatty acids composition of brown adipose tissue  

NASA Astrophysics Data System (ADS)

It has been demonstrated that thermogenic activity of brown adipose tissue (BAT) is higher during the early postnatal period, decreasing towards a low adult level. The present study examined postnatal changes in the lipid composition of BAT. BAT from pre-weaning rats at 4 and 14 days old showed the following differences in lipid composition compared to that from adults of 12 weeks old. (i) Relative weight of interscapular BAT to body weight was markedly greater. (ii) BAT-triglyceride (TG) level was lower, while BAT-phospholipid (PL)level was higher. (iii) In TG fatty acids (FA) polyunsaturated fatty acids (PU; mol %), arachidonate index (AI), unsaturation index (UI) and PU/saturated FA (SA) were higher; rare FA such as eicosadienoate, bishomo- ?-linolenic acid and lignoceric acid in mol % were also higher. (iv) In PL-FA monounsaturated FA (MU) in mol % was lower; PU mol %, AI and UI were higher. These features in BAT of pre-weaning rats resembled those in the cold-acclimated adults, suggesting a close relationship of the PL-FA profile to high activity of BAT.

Ohno, T.; Ogawa, K.; Kuroshima, A.

1992-03-01

150

Amino acid compositional shifts during streptophyte transitions to terrestrial habitats.  

PubMed

Across the streptophyte lineage, which includes charophycean algae and embryophytic plants, there have been at least four independent transitions to the terrestrial habitat. One of these involved the evolution of embryophytes (bryophytes and tracheophytes) from a charophycean ancestor, while others involved the earliest branching lineages, containing the monotypic genera Mesostigma and Chlorokybus, and within the Klebsormidiales and Zygnematales lineages. To overcome heat, water stress, and increased exposure to ultraviolet radiation, which must have accompanied these transitions, adaptive mechanisms would have been required. During periods of dehydration and/or desiccation, proteomes struggle to maintain adequate cytoplasmic solute concentrations. The increased usage of charged amino acids (DEHKR) may be one way of maintaining protein hydration, while increased use of aromatic residues (FHWY) protects proteins and nucleic acids by absorbing damaging UV, with both groups of residues thought to be important for the stabilization of protein structures. To test these hypotheses we examined amino acid sequences of orthologous proteins representing both mitochondrion- and plastid-encoded proteomes across streptophytic lineages. We compared relative differences within categories of amino acid residues and found consistent patterns of amino acid compositional fluxuation in extra-membranous regions that correspond with episodes of terrestrialization: positive change in usage frequency for residues with charged side-chains, and aromatic residues of the light-capturing chloroplast proteomes. We also found a general decrease in the usage frequency of hydrophobic, aliphatic, and small residues. These results suggest that amino acid compositional shifts in extra-membrane regions of plastid and mitochondrial proteins may represent biochemical adaptations that allowed green plants to colonize the land. PMID:21153633

Jobson, Richard W; Qiu, Yin-Long

2011-02-01

151

Fatty acid composition of the amphipod Dikerogammarus villosus: Feeding strategies and trophic links  

Microsoft Academic Search

Fatty acid (FA) compositions were determined for the invader amphipod Dikerogammarus villosus collected from July to September 2002, in an overheated, high-conductivity dammed reservoir in north-eastern France. Predominant fatty acids were the polyunsaturated fatty acids (PUFA): eicosapentaenoic acid (EPA), linoleic acid (LA), arachidonic acid (ARA), linolenic acid (LNA) together with the monounsaturated fatty acid 18:1?9 and the saturated fatty acid

Chafik Maazouzi; Gérard Masson; Maria Soledad Izquierdo; Jean-Claude Pihan

2007-01-01

152

Fatty acid composition of mature human milk of Egyptian and American women14  

Microsoft Academic Search

Fatty acid composition of mature human milk of rural Egyptian and American women was determined by gas-liquid chromatography. Milk of Egyptian women contained significantly higher percentages of capric, lauric, myristic, linoleic and arachidonic acids, saturated fatty acids (SFA), and polyunsaturated fatty acids (PUFA). Conversely, milk of American women contained higher percentages of stearic and oleic acids, total unsaturated fatty acids,

Marlene W Borschel; Robert G Elkin; Avanelle Kirksey; Osman Galal; Norge W Jerome

153

Polylactic acid composites incorporating casein functionalized cellulose nanowhiskers  

PubMed Central

Background Polylactic acid (PLA) is considered to be a sustainable alternative to petroleum-based polymers for many applications. Using cellulose fiber to reinforce PLA is of great interest recently due to its complete biodegradability and potential improvement of the mechanical performance. However, the dispersion of hydrophilic cellulose fibers in the hydrophobic polymer matrix is usually poor without using hazardous surfactants. The goal of this study was to develop homogenously dispersed cellulose nanowhisker (CNW) reinforced PLA composites using whole milk casein protein, which is an environmentally compatible dispersant. Results In this study, whole milk casein was chosen as a dispersant in the PLA-CNW system because of its potential to interact with the PLA matrix and cellulose. The affinity of casein to PLA was studied by surface plasmon resonance (SPR) imaging. CNWs were functionalized with casein and used as reinforcements to make PLA composites. Fluorescent staining of CNWs in the PLA matrix was implemented as a novel and simple way to analyze the dispersion of the reinforcements. The dispersion of CNWs in PLA was improved when casein was present. The mechanical properties of the composites were studied experimentally. Compared to pure PLA, the PLA composites had higher Young’s modulus. Casein (CS) functionalized CNW reinforced PLA (PLA-CS-CNW) at 2 wt% filler content maintained higher strain at break compared to normal CNW reinforced PLA (PLA-CNW). The Young’s modulus of PLA-CS-CNW composites was also higher than that of PLA-CNW composites at higher filler content. However, all composites exhibited lower strain at break and tensile strength at high filler content. Conclusions The presence of whole milk casein improved the dispersion of CNWs in the PLA matrix. The improved dispersion of CNWs provided higher modulus of the PLA composites at higher reinforcement loading and maintained the strain and stress at break of the composites at relatively low reinforcement loading. The affinity of the dispersant to PLA is important for the ultimate strength and stiffness of the composites.

2013-01-01

154

Three-dimensional assembly of Au nanoparticles using dipeptides  

NASA Astrophysics Data System (ADS)

An assembly of Au nanoparticles is fabricated by the condensation of peptide bonds between L-lysine molecules attached to the surface of 13 nm Au nanoparticles. The formation of peptide bonds between the L-lysine molecules is confirmed by Raman spectra. It is found that L-lysine molecules are absorbed onto the Au colloid surface via the interactions between the ?-amino group of L-lysine and the Au colloid. UV-visible spectral measurements show there are strong interactions between the Au nanoparticles linked by dipeptides (lysine-lysine) in the self-assembly. Transmission electron microscopy observations show that the distance between two adjacent nanoparticles is about 1.5 nm, which is consistent with the calculated length of the dipeptide.

Xu, Li; Guo, Yi; Xie, Renguo; Zhuang, Jiaqi; Yang, Wensheng; Li, Tiejin

2002-12-01

155

An amino acid composition criterion for membrane active antimicrobials  

NASA Astrophysics Data System (ADS)

Membrane active antimicrobials (AMPs) are short amphipathic peptides with broad spectrum anti microbial activity. While it is believed that their hydrophobic and cationic moieties are responsible for membrane-based mechanisms of action, membrane disruption by AMPs is manifested in a diversity of outcomes, such as pore formation, blebbing, and budding. This complication, along with others, have made a detailed, molecular understanding of AMPs difficult. We use synchrotron small angle xray scattering to investigate the interaction of model bacterial and eukaryotic cell membranes with archetypes from beta-sheet AMPs (e.g. defensins) and alpha-helical AMPs (e.g. magainins). The relationship between membrane composition and peptide induced changes in membrane curvature and topology is examined. By comparing the membrane rearrangement and phase behavior induced by these different peptides we will discuss the importance of amino acid composition on AMP design.

Schmidt, Nathan; Hwee Lai, Ghee; Mishra, Abhijit; Bong, Dennis; McCray, Paul, Jr.; Selsted, Michael; Ouellette, Andre; Wong, Gerard

2011-03-01

156

“Click dipeptide”: A novel stationary phase applied in two-dimensional liquid chromatography  

Microsoft Academic Search

2D-HPLC is an important technique for the separation of complex samples. Developing new types of stationary phases is of great interest to construct 2D-LC systems with high orthogonality. In this study, a novel stationary phase-Click dipeptide (l-phenylglycine dipeptide) was prepared by immobilization of ?-azido l-phenylglycine dipeptide on alkyne-silica via click chemistry. In the preparation of this new material, an efficient,

Meiyun Xue; Hongxue Huang; Yanxiong Ke; Changhu Chu; Yu jin; Xinmiao Liang

2009-01-01

157

Oxidative degradation of dipeptide (glycyl-glycine) by water-soluble colloidal manganese dioxide in the aqueous and micellar media.  

PubMed

The kinetics of the oxidative degradation of dipeptide glycyl-glycine (Gly-Gly) by water-soluble colloidal MnO(2) in acidic medium has been studied by employing visible spectrophotometer in the aqueous and micellar media at 35°C. To obtain the rate constants as functions of [Gly-Gly], [MnO(2)] and [HClO(4)], pseudo-first-order conditions were maintained in each kinetic run. The first-order-rate is observed with respect to [MnO(2)], whereas fractional-order-rates are determined in both [Gly-Gly] and [HClO(4)]. The addition of sodium pyrophosphate and sodium fluoride has composite effects (catalytic and inhibition). The reaction proceeds through the fast adsorption of Gly-Gly on the surface of the colloidal MnO(2). The observed results are discussed in terms of Michaelis-Menten/Langmuir-Hinshelwood model. The Arrhenius and Eyring equations are found valid for the reaction over a range of temperatures and different activation parameters have been evaluated. A probable reaction mechanism, in agreement with the observed kinetic results, has been proposed and discussed. The influence of changes in the surfactant concentrations on the observed rate constant is also investigated and the reaction followed the same type of kinetic behavior in micellar media. The pseudo-first-order rate constant (k(?)) is found to increase about two-fold with increase in [TX-100]. The catalytic effect of nonionic surfactant TX-100 is explained in terms of the mathematical model proposed by Tuncay et al. PMID:20870395

Akram, Mohd; Altaf, Mohammad; Kabir-ud-Din

2011-01-01

158

Quantitative effects of dietary polyunsaturated fats on the composition of fatty acids in rat tissues  

Microsoft Academic Search

A method combining data on fatty acid composition into subsets is used to illustrate general relative competitive selectivities\\u000a in the metabolic and transport events that maintain fatty acid compositions in tissue lipids and to minimize differences among\\u000a tissues or species in the amount of individual fatty acids. Fatty acid compositions of triglycerides and phospholipids in\\u000a several tissues of the rat

William E. M. Lands; Anna Morris; Bozena Libelt

1990-01-01

159

Cellular fatty acid compositions of "Achromobacter groups B and E".  

PubMed Central

Strains of "Achromobacter groups B and E" were examined for cellular fatty acid (CFA) composition to evaluate their chemical relatedness to known bacterial species and groups. The CFAs were liberated from whole cells by base hydrolysis, methylated, and analyzed by capillary gas-liquid chromatography. The CFA profiles of the two groups were identical and were distinct from CFA profiles of all other bacteria we have previously tested. These data provide support for results from whole-cell protein pattern analysis and DNA-DNA and rRNA-DNA hybridization studies, which show that "Achromobacter groups B and E" are biotypes of a single new genus and species.

Holmes, B; Moss, C W; Daneshvar, M I

1993-01-01

160

Acid gas scrubbing by composite solvent-swollen membranes  

DOEpatents

A composite immobilized liquid membrane suitable for acid gas scrubbing is disclosed. The membrane is a solvent-swollen polymer and a microporous polymeric support, the solvent being selected from a class of highly polar solvents containing at least one atom selected from nitrogen, oxygen, phosphorus and sulfur, and having a boiling point of at least 100 C and a solubility parameter of from about 7.5 to about 13.5 (cal/cm[sup 3]-atm)[sup 1/2]. Such solvents are homogeneously distributed through the solvent-swollen polymer from 20% to 95% by weight. Also disclosed are methods of acid gas scrubbing of high- and low-Btu gas effluents with such solvent-swollen membranes. 3 figs.

Matson, S.L.; Lee, E.K.L.; Friesen, D.T.; Kelly, D.J.

1988-04-12

161

Acid gas scrubbing by composite solvent-swollen membranes  

DOEpatents

A composite immobilized liquid membrane suitable for acid gas scrubbing is disclosed. The membrane is a solvent-swollen polymer and a microporous polymeric support, the solvent being selected from a class of highly polar solvents containing at least one atom selected from nitrogen, oxygen, phosphorous and sulfur, and having a boiling point of at least 100.degree. C. and a solubility parameter of from about 7.5 to about 13.5 (cal/cm.sup.3 -atm).sup.1/2. Such solvents are homogeneously distributed through the solvent-swollen polymer from 20% to 95% by weight. Also disclosed are methods of acid gas scrubbing of high- and low-Btu gas effluents with such solvent-swollen membranes.

Matson, Stephen L. (Harvard, MA) [Harvard, MA; Lee, Eric K. L. (Acton, MA) [Acton, MA; Friesen, Dwayne T. (Bend, OR) [Bend, OR; Kelly, Donald J. (Bend, OR) [Bend, OR

1988-01-01

162

Supervised learning method for the prediction of subcellular localization of proteins using amino acid and amino acid pair composition  

PubMed Central

Background Occurrence of protein in the cell is an important step in understanding its function. It is highly desirable to predict a protein's subcellular locations automatically from its sequence. Most studied methods for prediction of subcellular localization of proteins are signal peptides, the location by sequence homology, and the correlation between the total amino acid compositions of proteins. Taking amino-acid composition and amino acid pair composition into consideration helps improving the prediction accuracy. Results We constructed a dataset of protein sequences from SWISS-PROT database and segmented them into 12 classes based on their subcellular locations. SVM modules were trained to predict the subcellular location based on amino acid composition and amino acid pair composition. Results were calculated after 10-fold cross validation. Radial Basis Function (RBF) outperformed polynomial and linear kernel functions. Total prediction accuracy reached to 71.8% for amino acid composition and 77.0% for amino acid pair composition. In order to observe the impact of number of subcellular locations we constructed two more datasets of nine and five subcellular locations. Total accuracy was further improved to 79.9% and 85.66%. Conclusions A new SVM based approach is presented based on amino acid and amino acid pair composition. Result shows that data simulation and taking more protein features into consideration improves the accuracy to a great extent. It was also noticed that the data set needs to be crafted to take account of the distribution of data in all the classes.

Habib, Tanwir; Zhang, Chaoyang; Yang, Jack Y; Yang, Mary Qu; Deng, Youping

2008-01-01

163

Novel dipeptide macrocycles from 4-oxo, -thio, and -amino-substituted proline derivatives.  

PubMed

Dipeptide macrocycles of type A have been constructed in a versatile manner from the corresponding 4-heteroatom-substituted proline derivatives using an intramolecular Mitsunobu strategy. PMID:12027716

Arasappan, Ashok; Chen, Kevin X; Njoroge, F George; Parekh, Tejal N; Girijavallabhan, Viyyoor

2002-05-31

164

Evaluation of Fatty Acid and Amino Acid Compositions in Okra (Abelmoschus esculentus) Grown in Different Geographical Locations  

PubMed Central

Okra has different uses as a food and a remedy in traditional medicine. Since it produces many seeds, distribution of the plant is also quite easy. Although seed oil yield is low (4.7%), since the linoleic acid composition of the seed oil is quiet high (67.5%), it can still be used as a source of (UNSAT) unsaturated fatty acids. In this study, samples of okra grown in four different locations were analyzed to measure fatty acid and amino acid compositions. The content of the lipid extraction ranged from 4.34% to 4.52% on a dry weight basis. Quantitatively, the main okra fatty acids were palmitic acid (29.18–43.26%), linoleic acid (32.22–43.07%), linolenic acid (6.79–12.34%), stearic acid (6.36–7.73%), oleic acid (4.31–6.98%), arachidic acid (ND–3.48%), margaric acid (1.44–2.16%), pentadecylic acid (0.63–0.92%), and myristic acid (0.21–0.49%). Aspartic acid, proline, and glutamic acids were the main amino acids in okra pods, while cysteine and tyrosine were the minor amino acids. Statistical methods revealed how the fatty acid and amino acid contents in okra may be affected by the sampling location.

Sami, Rokayya; Lianzhou, Jiang; Yang, Li; Ma, Ying; Jing, Jing

2013-01-01

165

Trifluoromethyl-modified dipeptides by ZrCl4-promoted aza-Henry reactions.  

PubMed

Chiral (R)-1-phenylethylamine was successfully employed in a tandem aza-Henry addition-reduction reaction to give chiral ?-nitro ?-trifluoromethyl amines. A subsequent coupling reaction with N-Boc-protected amino acids leads to obtain optically pure CF3-modified dipeptides carrying two different N-protecting groups. These peptidomimetic units are characterized by the presence of the [CH(CF3)NH] group as mimetic of the natural [CONH] peptidic bond and can be used for the synthesis of more complex CF3-modified peptides after selective deprotection of one of the two amine functions. 2D NMR spectral analyses were employed to determine the absolute configurations of all newly synthesized chiral compounds. PMID:24802246

Fioravanti, Stefania; Pelagalli, Alessia; Pellacani, Lucio; Sciubba, Fabio; Vergari, Maria Cecilia

2014-08-01

166

Changes in fatty acid composition of Chlorella vulgaris by hypochlorous acid.  

PubMed

Hypochlorous acid treatment of a microalga, Chlorella vulgaris, was investigated to improve the quality of microalgal lipid and to obtain high biodiesel-conversion yield. Because chlorophyll deactivates the catalyst for biodiesel conversion, its removal in the lipid-extraction step enhances biodiesel productivity. When microalgae contacted the hypochlorous acid, chlorophyll was removed, and resultant changes in fatty acid composition of microalgal lipid were observed. The lipid-extraction yield after activated clay treatment was 32.7 mg lipid/g cell; after NaClO treatment at 0.8% available chlorine concentration, it was 95.2 mg lipid/g cell; and after NaCl electrolysis treatment at the 1 g/L cell concentration, it was 102.4 mg lipid/g cell. While the contents of all of the unsaturated fatty acids except oleic acid, in the microalgal lipid, decreased as the result of NaClO treatment, the contents of all of the unsaturated fatty acids including oleic acid decreased as the result of NaCl electrolysis treatment. PMID:24785789

Park, Ji-Yeon; Choi, Sun-A; Jeong, Min-Ji; Nam, Bora; Oh, You-Kwan; Lee, Jin-Suk

2014-06-01

167

Acid Rain Affecting the Electrical Properties of Outdoor Composite Dielectric Materials  

Microsoft Academic Search

Acid rain is precipitation with acidity, i.e., pH, below 5.6. There is an increasing interest in the degradation of the electrical properties of outdoor composite dielectric materials under severe contaminant conditions such as acid rain. In this study, the degradation effects of acid rain on the outdoor composite dielectrics are investigated by accelerated aging due to artificial acid rain. Based

Xinsheng Wang; Seiji Kumagai; Noboru Yoshimura

1998-01-01

168

Amino acid composition of processed fish silage using different raw materials  

Microsoft Academic Search

The objective was to evaluate amino acid composition of silages produced from three raw materials. Commercial marine fish waste, commercial freshwater fish waste, and tilapia filleting residue were used to produce fish silage by acid digestion (20ml\\/kg formic acid and 20ml\\/kg sulfuric acid) and anaerobic fermentation (50g\\/kg Lactobacillus plantarum, 150g\\/kg sugar cane molasses). Protein content and amino acid composition were

Rose Meire Vidotti; Elisabete Maria Macedo Viegas; Dalton José Carneiro

2003-01-01

169

Whole-genome association study for fatty acid composition of oleic acid in Japanese Black cattle.  

PubMed

Fatty acid composition, especially oleic acid (C18:1), plays an important role in the eating quality of meat in Japanese Black cattle. Therefore, the objective of this study was to identify loci associated with C18:1 in the intramuscular fat of the trapezius muscles in Japanese Black cattle using the Illumina BovineSNP50 BeadChip whole genome single nucleotide polymorphism (SNP) assay. We also evaluated the relationship between C18:1 and three fatty acid synthesis genes, fatty acid synthase (FASN), stearoyl-CoA desaturase and sterol regulatory element-binding protein-1. In this experiment, we applied a mixed model and Genomic Control approach using selective genotyping to perform a genome-wide association study. A total of 160 animals (80 animals with higher values and 80 animals with lower values), selected from 3356 animals based on corrected phenotype, were genotyped using the Illumina BovineSNP50 BeadChip and three fatty acid synthesis genes, and the quality of these SNPs was assessed. In this study, a total of 38?955 SNPs, which included SNPs in the three fatty acid synthesis genes, were used, and the estimated inflation factor was 1.06. In the studied population, a total of 32 SNPs, including the FASN gene, had significant effects, and in particular 30 SNPs of all significant SNPs were located between 49 and 55?Mbp on chromosome 19. This study is one of the first genome-wide association studies for fatty acid composition in a cattle population using the recently released Illumina BovineSNP50 BeadChip. PMID:20590532

Uemoto, Y; Abe, T; Tameoka, N; Hasebe, H; Inoue, K; Nakajima, H; Shoji, N; Kobayashi, M; Kobayashi, E

2011-04-01

170

Fatty acid composition of Ruditapes decussatus spat fed on different microalgae diets  

Microsoft Academic Search

The fatty acid composition of the Ruditapes decussatus spat fed on three different microalgal diets during 4 weeks was determined. The fatty acid pattern of each diet was also analysed. The diets used were Isochrysis galbana, clone T-ISO, Tetraselmis suecica, and Phaeodactylum tricornutum. The fatty acid composition of the spat was usually well correlated with that of the diet supplied.

M. Albentosa; U. Labarta; M. J. Fernández-Reiriz; A. Pérez-Camacho

1996-01-01

171

Xenon isotopic composition in acid residues of EL Taco inclusions  

NASA Astrophysics Data System (ADS)

The IAB and IIICD groups of iron meteorites contain silicate inclusions of nearly unequilbrated chondritic type, and models have been proposed to explain the origin of these groups, which are different from the magmatic group of iron meteorites. We analyzed acid residues of IAB Campo del Cielo (El Taco) for their noble gases; the Xe isotopic composition in the C phase of these residues is discussed. About 12-15 g of the meteorite, which also contained parts of several macro inclusions were treated with 4M HNO3 and the residue separated into different parts according to their density. These separates were analyzed for noble gases following standard mass spectrometric procedures. In the major silicates there are correlated excesses at Kr-80 and Kr-82 due to (n, gamma) capture reactions on Br-79 and Br-81 respectively. For the Xe isotopes, there are correlated excesses at Xe-128 and Xe-129 showing that these inclusions have incorporated live I-129 in them. The Xe isotopic composition obtained in the graphite phase of these inclusions is discussed. The measured Xe amounts in these graphic samples are in the range of 10-20 x 10-10/cu cm/STP, which is much larger than those in the silicates. The low-temperature runs of the stepwise heating experiments have a Xe isotopic composition similar to atmospheric, probably due to adsorption. The temperature steps above 1000 C, where the contribution from atmospheric adsorbed Xe should be minimal, have isotopic compositions distinctly different from the low-temperature steps and are significantly different from the terrestrial values. The heavier Xe isotopes are clearly enhanced by about 2.5% per amu relative to solar Xe, which is the same tendency, although not quite as pronounced, as is observed for terrestrial Xe.

Mathew, K. J.; Begemann, F.

1994-07-01

172

Fatty acid and sn-2 fatty acid composition in human milk from Granada (Spain) and in infant formulas  

Microsoft Academic Search

Objective: To investigate differences in fatty acid and sn-2 fatty acid composition in colostrum, transitional and mature human milk, and in term infant formulas.Setting: Departament de Nutrició i Bromatologia, University of Barcelona, Spain and University Hospital of Granada, Spain.Subjects: One-hundred and twenty mothers and 11 available types of infant formulas for term infants.Design: We analysed the fatty acid composition of

A López-López; MC López-Sabater; C Campoy-Folgoso; M Rivero-Urgell; AI Castellote-Bargalló

2002-01-01

173

The major metabolite of dipeptide piracetam analogue GVS-111 in rat brain and its similarity to endogenous neuropeptide cyclo- l -prolylglycine  

Microsoft Academic Search

Summary  The metabolism of a new piracetam analogue, the dipeptide cognitive enhancer N-phenylacetyl-l-prolylglycine ethyl ester (GVS-111) was studied in vivo. GVS-111 itself was not found in rat brain 1 h after 5 mg\\/kg i.p.\\u000a administration up to limit of detection (LOD) under high performance liquid chromatography (HPLC) conditions. Three substances\\u000a corresponding to the three possible GVS-111 metabolites, namely phenylacetic acid, prolylglycine

T. A. Gudasheva; S. S. Boyko; R. U. Ostrovskaya; T. A. Voronina; V. K. Akparov; S. S. Trofimov; G. G. Rozantsev; A. P. Skoldinov; V. P. Zherdev; S. B. Seredenin

1997-01-01

174

The inactivation of bovine cathepsin B by novel N-chloro-acetyl-dipeptides: Application of the Houghten ‘tea bag’ methodology to inhibitor synthesis  

Microsoft Academic Search

In this study, a series of N-chloro-acetylated dipeptides were synthesised by the application of Houghten’s methodology of multiple analog peptide syntheses (MAPS). The peptides, all of which contain a C-terminal free acid, were tested as inactivators of bovine cathepsin B, in an attempt at exploiting the known and, amongst the cysteine proteinases, unique carboxy dipeptidyl peptidase activity of the protease.

B. F. Gilmore; P. Harriott; B. Walker

2005-01-01

175

The dipeptide H-Trp-Glu-OH (WE) shows agonistic activity to peroxisome proliferator-activated protein-? and reduces hepatic lipid accumulation in lipid-loaded H4IIE cells.  

PubMed

Dipeptides digested from dietary proteins can be directly absorbed by the intestine and delivered to the circulatory system. However, the dipeptides' metabolic roles and biological activities are largely unknown. Lipid-loaded HII4E cells stimulated with H-Trp-Glu-OH (WE) exhibited reduced lipid accumulation, of which the effect was abolished by peroxisome proliferator-activated receptor (PPAR) ? gene knock down. A luciferase assay showed that the WE dipeptide induced PPAR? transactivation in a dose-dependent manner. Surface plasmon resonance and time-resolved fluorescence resonance energy transfer analyses demonstrated that WE interacts directly with the PPAR? ligand binding domain (KD, 120?M; EC50, 83?M). Cells stimulated with WE induced PPAR? and its responsive genes and increased cellular fatty acid uptake. In conclusion, WE reduces hepatic lipid accumulation in lipid-loaded hepatocytes via the activation of PPAR? by a direct interaction. PMID:24821375

Jia, Yaoyao; Kim, Jong-Ho; Nam, Bora; Kim, Jiyoung; Lee, Ji Hae; Hwang, Kwang-Yeon; Lee, Sung-Joon

2014-07-01

176

Effects of feeding bile acids and a bile acid sequestrant on hepatic bile acid composition in mice[S  

PubMed Central

An improved ultra performance liquid chromatography-tandem mass spectrometry (UPLC/MS/MS) method was established for the simultaneous analysis of various bile acids (BA) and applied to investigate liver BA content in C57BL/6 mice fed 1% cholic acid (CA), 0.3% deoxycholic acid (DCA), 0.3% chenodeoxycholic acid (CDCA), 0.3% lithocholic acid (LCA), 3% ursodeoxycholic acid (UDCA), or 2% cholestyramine (resin). Results indicate that mice have a remarkable ability to maintain liver BA concentrations. The BA profiles in mouse livers were similar between CA and DCA feedings, as well as between CDCA and LCA feedings. The mRNA expression of Cytochrome P450 7a1 (Cyp7a1) was suppressed by all BA feedings, whereas Cyp7b1 was suppressed only by CA and UDCA feedings. Gender differences in liver BA composition were observed after feeding CA, DCA, CDCA, and LCA, but they were not prominent after feeding UDCA. Sulfation of CA and CDCA was found at the 7-OH position, and it was increased by feeding CA or CDCA more in male than female mice. In contrast, sulfation of LCA and taurolithocholic acid (TLCA) was female-predominant, and it was increased by feeding UDCA and LCA. In summary, the present systematic study on BA metabolism in mice will aid in interpreting BA-mediated gene regulation and hepatotoxicity.

Zhang, Youcai; Klaassen, Curtis D.

2010-01-01

177

Efficacy of Parenteral Nutrition Supplemented With Glutamine Dipeptide to Decrease Hospital Infections in Critically Ill Surgical Patients  

PubMed Central

Background Nosocomial infections are an important cause of morbidity and mortality in the surgical intensive care unit (SICU). Clinical benefits of glutamine-supplemented parenteral nutrition may occur in hospitalized surgical patients, but efficacy data in different surgical subgroups are lacking. The objective was to determine whether glutamine-supplemented parenteral nutrition differentially affects nosocomial infection rates in selected subgroups of SICU patients. Methods This was a double-blind, randomized, controlled study of alanyl-glutamine dipeptide-supplemented parenteral nutrition in SICU patients requiring parenteral nutrition and SICU care after surgery for pancreatic necrosis, cardiac, vascular, or colonic surgery. Subjects (n = 59) received isocaloric/isonitrogenous parenteral nutrition, providing 1.5 g/kg/d standard glutamine-free amino acids (STD-PN) or 1.0 g/kg/d standard amino acids + 0.5 g/kg/d glutamine dipeptide (GLN-PN). Enteral feedings were advanced as tolerated. Nosocomial infections were determined until hospital discharge. Results Baseline clinical/metabolic data were similar between groups. Plasma glutamine concentrations were low in all groups and were increased by GLN-PN. GLN-PN did not alter infection rates after pancreatic necrosis surgery (17 STD-PN and 15 GLN-PN patients). In nonpancreatic surgery patients (12 STD-PN and 15 GLN-PN), GLN-PN was associated with significantly decreased total nosocomial infections (STD-PN 36 vs GLN-PN 13, P < .030), bloodstream infections (7 vs 0, P < .01), pneumonias (16 vs 6, P < .05), and infections attributed to Staphylococcus aureus (P < .01), fungi, and enteric Gram-negative bacteria (each P < .05). Conclusions Glutamine dipeptide-supplemented parenteral nutrition did not alter infection rates following pancreatic necrosis surgery but significantly decreased infections in SICU patients after cardiac, vascular, and colonic surgery.

Estivariz, Concepcion F.; Griffith, Daniel P.; Luo, Menghua; Szeszycki, Elaina E.; Bazargan, Niloofar; Dave, Nisha; Daignault, Nicole M.; Bergman, Glen F.; McNally, Therese; Battey, Cindy H.; Furr, Celeste E.; Hao, Li; Ramsay, James G.; Accardi, Carolyn R.; Cotsonis, George A.; Jones, Dean P.; Galloway, John R.; Ziegler, Thomas R.

2011-01-01

178

Protonated Dipeptide Losses from b 5 and b 4 Ions of Side Chain Hydroxyl Group Containing Pentapeptides  

NASA Astrophysics Data System (ADS)

In this study, C-terminal protonated dipeptide eliminations were reported for both b 5 and b 4 ions of side chain hydroxyl group (-OH) containing pentapeptides. The study utilized the model C-terminal amidated pentapeptides having sequences of XGGFL and AXVYI, where X represents serine (S), threonine (T), glutamic acid (E), aspartic acid (D), or tyrosine (Y) residue. Upon low-energy collision-induced dissociation (CID) of XGGFL (where X = S, T, E, D, and Y) model peptide series, the ions at m/z 279 and 223 were observed as common fragments in all b 5 and b 4 ion (except b 4 ion of YGGFL) mass spectra, respectively. By contrast, peptides, namely SMeGGFL-NH2 and EOMeGGFL-NH2, did not show either the ion at m/z 279 or the ion at m/z 223. It is shown that the side chain hydroxyl group is required for the possible mechanism to take place that furnishes the protonated dipeptide loss from b 5 and b 4 ions. In addition, the ions at m/z 295 and 281 were detected as common fragments in all b 5 and b 4 ion (except b 4 ion of AYVYI) mass spectra, respectively, for AXVYI model peptide series. The MS4 experiments exhibited that the fragment ions at m/z 279, 223, 295, and 281 entirely reflect the same fragmentation behavior of [M + H]+ ion generated from commercial dipeptides FL-OH, GF-OH, YI-OH, and VY-OH. These novel eliminations reported here for b 5 and b 4 ions can be useful in assigning the correct and reliable peptide sequences for high-throughput proteomic studies.

Atik, A. Emin; Yalcin, Talat

2013-10-01

179

Nanophase Alumina/Poly(L-Lactic Acid) Composite Scaffolds for Biomedical Applications.  

National Technical Information Service (NTIS)

Three-dimensional composites of nanophase alumina and poly(L-lactic acid) with an interconnected porous network and an overall porosity in excess of 90% are cytocompatible. Osteoblast proliferation on the nanophase ceramic/ polymer composites is a functio...

A. J. Tulloch R. Bizios R. W. Siegel

2003-01-01

180

Mechanism of a model dipeptide transport across blood-ocular barriers following systemic administration  

Microsoft Academic Search

The purposes of this study were to provide functional evidence for the presence of a peptide transporter on blood-ocular barriers and to elucidate the mechanism of a dipeptide transport across these barriers following systemic administration. Glycylsarcosine was chosen as a model dipeptide and [3H] glycylsarcosine was administered through the marginal ear vein of New Zealand white rabbits. At the end

Harisha Atluri; Banmeet S Anand; Jignesh Patel; Ashim K Mitra

2004-01-01

181

Amino Acid Composition of Grain Protein of Maize from Matched Pairs of Organic and Conventional Fields.  

National Technical Information Service (NTIS)

Measurements are reported of the amino acid composition of protein from maize (Zea mays L.) grain raised on fourteen pairs of organic and conventional fields which were matched for location, cultivar, planting date, and soil type. The amino acid compositi...

J. L. Wolfson G. Shearer

1979-01-01

182

Intramolecular condensation reactions in protonated dipeptides: carbon monoxide, water, and ammonia losses in competition.  

PubMed

The elimination of carbon monoxide and water from a series of protonated dipeptides, [XxxYyy + H](+), is investigated by tandem mass spectrometry experiments and density functional theory. The combined results show that CO loss occurs on the a(1)-y(1) pathway, which begins by rearrangement of the added proton to the amide N-atom and creates the proton-bound dimer of an amino acid (Yyy) and an imine (that from Xxx residue). The loss of H(2)O is initiated from a tautomer in which the added proton has migrated to the hydroxyl group of the C-terminus, thereby promoting the formation of an ion with protonated oxazolone structure (a nominal b(2) ion). The highest yields of [XxxYyy + H - CO](+) and [XxxYyy + H - H(2)O](+) are observed at threshold energies. As the internal energy of the protonated dipeptides increases, these primary products are depleted by consecutive dissociations yielding mostly backbone fragments. Specifically, [XxxYyy + H - CO](+) decomposes to y(1) (protonated Yyy) and a(1) (immonium ion of Xxx residue), while [XxxYyy + H - H(2)O](+) produces a(2) and the immonium ions of residues Xxx (a(1)) and Yyy ("internal" immonium ion). Water loss takes place more efficiently when the more basic residue is at the C-terminal position. Increasing the basicity of the N-terminal residue enhances the extent of CO versus H(2)O loss and introduces the competitive elimination of NH(3). The dissociations leading to eliminations of small neutrals (CO, H(2)O, etc.) generally proceed over transition states that lie higher in energy than the corresponding dissociation products. The excess energy is disposed of either in translational or rovibrational modes of the products, depending on the stability of the incipient noncovalent assemblies emerging during the cleavage of the small neutrals. PMID:15234362

Pingitore, Francesco; Polce, Michael J; Wang, Ping; Wesdemiotis, Chrys; Paizs, Béla

2004-07-01

183

Effect of dietary fatty acids on antibody production and fatty acid composition of lymphoid organs in broiler chicks.  

PubMed

This study examined the effect of increasing amounts of dietary polyunsaturated fatty acids on antibody production in vivo and fatty acid composition of plasma and lymphoid tissues in the broiler. Chicks were fed four diets containing 12% added fat made up of different proportions of palm oil and soybean oil and immunized against bovine serum albumin at 14 to 16 d of age. Blood samples were taken every 4 to 5 d for 30 d; then the chicks were killed and liver, spleen, thymus, bursa of Fabricius, and bone marrow were sampled. Fatty acid composition in serum and tissues reflected the composition of the diets, although amounts of saturated fatty acids were tissue-specific. Arachidonic acid concentration was not changed by dietary fatty acid content. Antibody production developed more rapidly, reached a higher level, and was more persistent in the chicks fed lower levels of linoleic acid. A quadratic relationship was found between tissue linoleic acid or total polyunsaturated fatty acid concentrations and antibody production at 11 and 14 d after challenge. No correlation was found with arachidonic acid. It is concluded that dietary fatty acid composition can influence immune response in broilers. PMID:7501591

Friedman, A; Sklan, D

1995-09-01

184

Proton conductivity of phosphoric acid doped polybenzimidazole and its composites with inorganic proton conductors  

Microsoft Academic Search

Phosphoric acid doped polybenzimidazole (PBI) and PBI composite membranes have been prepared in the present work. The PBI composites contain inorganic proton conductors including zirconium phosphate (ZrP), (Zr(HPO4)2·nH2O), phosphotungstic acid (PWA), (H3PW12O40·nH2O) and silicotungstic acid (SiWA), (H4SiW12O40·nH2O). The conductivity of phosphoric acid doped PBI and PBI composite membranes was found to be dependent on the acid doping level, relative humidity

Ronghuan He; Qingfeng Li; Gang Xiao; Niels J. Bjerrum

2003-01-01

185

Unusual fatty acid compositions of the hyperthermophilic archaeon Pyrococcus furiosus and the bacterium Thermotoga maritima.  

PubMed Central

The fatty acid compositions of the hyperthermophilic microorganisms Thermotoga maritima and Pyrococcus furiosus were studied and compared. A total of 37 different fatty acids were identified in T. maritima, including the novel 13,14-dimethyloctacosanedioic acid. In contrast, a total of 18 different fatty acids were characterized, as minor components, in P. furiosus, and these included saturated, monounsaturated, and dicarboxylic acids. This is the first report of fatty acids from an archaeon.

Carballeira, N M; Reyes, M; Sostre, A; Huang, H; Verhagen, M F; Adams, M W

1997-01-01

186

The fatty acid composition of milk fat as influenced by feeding oilseeds  

Microsoft Academic Search

The fatty acid composition of bovine milk fat can be substantially altered by feeding lipid sources which alter the fatty acid profile of lipid entering the intestine from the rumen. As long-chain fatty acids of dietary origin can be incorporated directly into milk fat the opportunity exists to alter the ratio of short and long-chain fatty acids as well as

John J. Kennelly

1996-01-01

187

Identification of thermophilic species by the amino acid compositions deduced from their genomes.  

PubMed

The global amino acid compositions as deduced from the complete genomic sequences of six thermophilic archaea, two thermophilic bacteria, 17 mesophilic bacteria and two eukaryotic species were analysed by hierarchical clustering and principal components analysis. Both methods showed an influence of several factors on amino acid composition. Although GC content has a dominant effect, thermophilic species can be identified by their global amino acid compositions alone. This study presents a careful statistical analysis of factors that affect amino acid composition and also yielded specific features of the average amino acid composition of thermophilic species. Moreover, we introduce the first example of a 'compositional tree' of species that takes into account not only homologous proteins, but also proteins unique to particular species. We expect this simple yet novel approach to be a useful additional tool for the study of phylogeny at the genome level. PMID:11266564

Kreil, D P; Ouzounis, C A

2001-04-01

188

Effects of Polyunsaturated Fatty Acids in Growth Medium on Lipid Composition and on Physicochemical Surface Properties of Lactobacilli  

Microsoft Academic Search

Most probiotic lactobacilli adhere to intestinal surfaces, a phenomenon influenced by free polyunsaturated fatty acids (PUFA). The present study investigated whether free linoleic acid, -linolenic acid, arachidonic acid, -linolenic acid, or docosahexaenoic acid in the growth medium alters the fatty acid composition of lactobacilli and their physical characteristics. The most abundant bacterial fatty acids identified were oleic, vaccenic, and dihydrosterculic

P. Kankaanpaa; B. Yang; H. Kallio; E. Isolauri; S. Salminen

2004-01-01

189

Trans fatty acids and fatty acid composition of mature breast milk in turkish women and their association with maternal diet's.  

PubMed

The aim of this study was to determine the fatty acid composition and trans fatty acid and fatty acid contents of breast milk in Turkish women and to find the effect of breastfeeding mothers' diet on trans fatty acid and fatty acid composition. Mature milk samples obtained from 50 Turkish nursing women were analyzed. Total milk lipids extracts were transmethylated and analyzed by using gas liquid chromatography to determine fatty acids contents. A questionnaire was applied to observe eating habits and 3 days dietary records from mothers were obtained. Daily dietary intake of total energy and nutrients were estimated by using nutrient database. The mean total trans fatty acids contents was 2.13 +/- 1.03%. The major sources of trans fatty acids in mothers' diets were margarines-butter (37.0%), bakery products and confectionery (29.6%). Mothers who had high level of trans isomers in their milk consumed significantly higher amounts of these products. Saturated fatty acids, polyunsaturated fatty acids and monounsaturated fatty acids of human milk constituted 40.7 +/- 4.7%, 26.9 +/- 4.2% and 30.8 +/- 0.6% of the total fatty acids, respectively. The levels of fatty acids in human milk may reflect the current diet of the mother as well as the diet consumed early in pregnancy. Margarines, bakery products and confectionery are a major source of trans fatty acids in maternal diet in Turkey. PMID:19280240

Samur, Gülhan; Topcu, Ali; Turan, Semra

2009-05-01

190

Seasonal Variations in Fatty Acid Composition and the N-6\\/N-3 Fatty Acid Ratio of Pikeperch (Sander LUCIOPERCA) Muscle Lipids  

Microsoft Academic Search

Total lipid, fatty acid composition and the N-6\\/N-3 fatty acid ratios of muscle of pikeperch (Sander lucioperca) was determined once every two months. The ratio of unsaturated fatty acids (UFA) was higher than half of the total fatty acid content, and the monounsaturated fatty acid (MUFA) was higher than the polyunsaturated fatty acid (PUFA) ratio. The n-3 fatty acids were

Kazim Uysal; M. Yasar Aksoylar

2005-01-01

191

Continuous microcellular foaming of polylactic acid/natural fiber composites  

NASA Astrophysics Data System (ADS)

Poly(lactic acid) (PLA), a biodegradable thermoplastic derived from renewable resources, stands out as a substitute to petroleum-based plastics. In spite of its excellent properties, commercial applications are limited because PLA is more expensive and more brittle than traditional petroleum-based resins. PLA can be blended with cellulosic fibers to reduce material cost. However, the lowered cost comes at the expense of flexibility and impact strength, which can be enhanced through the production of microcellular structures in the composite. Microcellular foaming uses inert gases (e.g., carbon dioxide) as physical blowing agents to make cellular structures with bubble sizes of less than 10 microm and cell-population densities (number of bubbles per unit volume) greater than 109 cells/cm³. These unique characteristics result in a significant increase in toughness and elongation at break (ductility) compared with unfoamed parts because the presence of small bubbles can blunt the crack-tips increasing the energy needed to propagate the crack. Microcellular foams have been produced through a two step batch process. First, large amounts of gas are dissolved in the solid plastic under high pressure (sorption process) to form a single-phase solution. Second, a thermodynamic instability (sudden drop in solubility) triggers cell nucleation and growth as the gas diffuses out of the plastic. Batch production of microcellular PLA has addressed some of the drawbacks of PLA. Unfortunately, the batch foaming process is not likely to be implemented in the industrial production of foams because it is not cost-effective. This study investigated the continuous microcellular foaming process of PLA and PLA/wood-fiber composites. The effects of the processing temperature and material compositions on the melt viscosity, pressure drop rate, and cell-population density were examined in order to understand the nucleation mechanisms in neat and filled PLA foams. The results indicated that the processing temperature had a strong effect of the rheology of the melt and cell morphology. Processing at a lower temperature significantly increased the cell nucleation rate of neat PLA (amorphous and semi-crystalline) because of the fact that a high melt viscosity induced a high pressure drop rate in the polymer/gas solution. The presence of nanoclay did not affect the homogeneous nucleation but increased the heterogeneous nucleation, allowing both nucleation mechanisms to occur during the foaming process. The effect of wood-flour (0-30 wt.%) and rheology modifier contents on the melt viscosity and cell morphology of microcellular foamed composites was investigated. The viscosity of the melt increased with wood-flour content and decreased with rheology modifier content, affecting the processing conditions (i.e., pressure drop and pressure drop rate) and foamability of the composites. Matching the viscosity of the composites with that of neat PLA resulted in the best cell morphologies. Physico-mechanical characterization of microcellular foamed PLA as a function of cell morphology was performed to establish process-morphology-property relationships. The processing variables, i.e., amount of gas injected, flow rate, and processing temperature affected the development of the cellular structure and mechanical properties of the foams.

Diaz-Acosta, Carlos A.

192

Intercepted solar radiation affects oil fatty acid composition in crop species  

Microsoft Academic Search

Solar radiation intercepted during grain filling affects growth of grain crops. Its effects on oil fatty acid composition have not been investigated. The objective of this work was to investigate the effect of intercepted solar radiation per plant on oil fatty acid composition in four crops. An experiment including a cultivar of soybean, maize and sunflower was sown at Balcarce,

N. G. Izquierdo; L. A. N. Aguirrezábal; F. H. Andrade; C. Geroudet; O. Valentinuz; M. Pereyra Iraola

2009-01-01

193

Effects of n-3 polyunsaturated fatty acid supplementation in pregnancy on maternal and fetal erythrocyte fatty acid composition  

Microsoft Academic Search

Objective: The aim of this study was to assess the effects of fish oil supplementation in pregnancy on maternal erythrocyte fatty acid composition at different stages of pregnancy and in the post-partum period, and on neonatal erythrocyte fatty acid composition.Design: A double-blind, randomised, placebo-controlled study.Setting: Subiaco, Western Australia.Subjects: In all, 98 women booked for delivery at St John of God

J A Dunstan; T A Mori; A Barden; L J Beilin; P G Holt; P C Calder; A L Taylor; S L Prescott

2004-01-01

194

Amino acid nitrogen isotopic composition patterns in lacustrine sedimenting matter  

NASA Astrophysics Data System (ADS)

Amino acids (AAs) comprise a large fraction of organic nitrogen (N) in plankton and sedimenting matter. Aquatic studies of organic N compounds in general and of AAs in particular, mostly concentrate on marine environments. In order to study the cycling and fate of organic N and AAs in lakes, we measured the N isotopic composition (?15N) of bulk organic matter (OM) and of single hydrolysable AAs in sediment trap and sediment samples from two Swiss lakes with contrasting trophic state: Lake Brienz, an oligotrophic lake with an oxic water column, and Lake Zug a eutrophic, meromictic lake. We also measured the N isotopic composition of water column nitrate, the likely inorganic N source during biosynthesis in both lakes. The ?15N-AA patterns found for the sediment trap material were consistent with published ?15N-AA data for marine plankton. The AA composition and primary ?15N-AA signatures are preserved until burial in the sediments. During early sedimentary diagenesis, the ?15N values of single AAs appear to increase, exceeding those of the bulk OM. This increase in ?15N-AA is paralleled by a decreased contribution of AAs to the total OM pool with progressed degradation, suggesting preferential AA degradation associated with a significant N isotope fractionation. Indicators for trophic level based on ?15N-AAs were determined, for the first time in lacustrine systems. In our samples, the trophic AAs were generally enriched in 15N compared to source AAs and higher trophic ?15N-AA values in Lake Zug were consistent with a higher trophic level of the bulk biomass compared to Lake Brienz. Especially the difference between average trophic ?15N-AAs and average source ?15N-AAs was sensitive to the trophic states of the two lakes. A proxy for total heterotrophic AA re-synthesis (?V), which is strongly associated with heterotrophic microbial reworking of the OM, was calculated based on ?15N values of trophic AAs. Higher ?V in Lake Brienz indicate enhanced heterotrophic bacterial reworking of AAs under oligotrophic conditions. Despite changes in the ?15N-AA values within the sediments, the proxies based on these values were consistent over the studied sediment profile, indicating the preservation of trophic signatures; therefore, our results underscore that ?15N-AA analysis of sedimentary records represents a promising tool to assess trophic levels and bacterial re-synthesis in lakes.

Carstens, Dörte; Lehmann, Moritz F.; Hofstetter, Thomas B.; Schubert, Carsten J.

2013-11-01

195

Effect of Waste Polymer Additives on the Properties of Acid Resistant Composites  

Microsoft Academic Search

The present work describes preparation of acid resistant composites from porphyrite and wollastonite by adding wastes of furfurol (PA1) and furfuryl alcohol (PA2) production as the polymer additives. The effects of waste polymer additives on the compressive strength, chemical resistance and adhesive ability of the composites were examined. The mechanism of the hydration process and phase evaluation of the composites

Zamira MUHAMEDBAEVA; Yunhua XU; Fazhan Wang

2008-01-01

196

Fabrication and Mechanical Properties of Completely Biodegradable Hemp Fiber Reinforced Polylactic Acid Composites  

Microsoft Academic Search

Biodegradable composite materials can be produced by the combination of biodegradable polymers and natural fibers. In this study, a new biodegradable composite of hemp fiber reinforced polylactic acid (PLA) was fabricated using the hot press method. Mechanical properties of composites with different fiber volume fractions were tested. The optimum fiber content was determined according to the test results. Effects of

Ruihua Hu; Jae-Kyoo Lim

2007-01-01

197

Preparation and characterization of polyaniline\\/manganese dioxide composites via oxidative polymerization: Effect of acids  

Microsoft Academic Search

Polyaniline\\/manganese dioxide (PANI\\/MnO2) composites have been chemically prepared by oxidative polymerization of aniline in acidic medium containing MnO2 as an oxidant. The acids used were; H2SO4, HNO3, HCl, and H3PO4 The prepared composites were characterized by SEM, elemental analysis, FT-IR, XRD, TGA, and magnetic susceptibility. XRD measurements of the composites revealed that the crystal structure of incorporated MnO2 undergone a

Ali H. Gemeay; Ikhlas A. Mansour; Rehab G. El-Sharkawy; Ahmed B. Zaki

2005-01-01

198

Amino acid composition of dynein and comparison with myosin.  

PubMed

A comparison is made between dynein [flagellar ATPase; EC 3.6.1.3], purified from sea urchin sperm flagella, and muscle myosin. The amino acid composition of dynein was found to be statistically different from that of myosin. The same was true of their tryptic fragments retaining ATPase activity, i.e., Fragment A of dynein and heavy meromyosin. At low ionic strength, no superprecipitation took place when ATP was added to a mixture of dynein and actin, and stimulation of the Mg2+-ATPase activity of dynein remained below 50% even when a one-hundred-fold excess of actin was present. No viscosity drop was caused by adding ATP to a solution containing dynein and actin. Anti-myosin antiserum did not react with dynein, while anti-Fragment A antiserum formed no precipit-n line against myosin. Furthermore, the amount of dynein that combined with F-actin was less than one-fifth of the amount of dynein that fully combined with microtubules. These results are consistent with the dissimilarity in enzymatic and other physiocochemical properties of these two proteins. PMID:129468

Ogawa, K; Okuno, M; Mohri, H

1975-10-01

199

Hydrofluoric acid-resistant composite window and method for its fabrication  

DOEpatents

A hydrofluoric acid-resistant composite window and method for its fabrication are disclosed. The composite window comprises a window having first and second sides. The first side is oriented towards an environment containing hydrofluoric acid. An adhesive is applied to the first side. A layer of transparent hydrofluoric acid-resistant material, such as Mylar, is applied to the adhesive and completely covers the first side. The adhesive is then cured.

Ostenak, C.A.; Mackay, H.A.

1985-07-18

200

Effects of conjugated linoleic acid on the belly firmness and fatty acid composition of genetically lean pigs1,2  

Microsoft Academic Search

A study of the effects of conjugated lino- leic acid (CLA) on the belly firmness and fatty acid composition of genetically lean pigs was conducted. From 75 to 120 kg live weight, 30 gilts were allowed ad libitum access to a corn-soybean meal diet supple- mented with either 1% CLA oil (CLA-60) or 1% sun- flower oil (SFO) or were

J. M. Eggert; M. A. Belury; A. Kempa-Steczko; S. E. Mills; A. P. Schinckel

201

The changes of fatty acid and amino acid compositions in sea bream ( Sparus aurata) during irradiation process  

NASA Astrophysics Data System (ADS)

Aqua cultured fish (sea bream) were irradiated by Cobalt-60 at commercial irradiation facility at dose of 2.5 and 5 kGy at 2-4 °C. The proximate composition, fatty acid and amino acid composition changes of irradiated aqua cultured sea bream ( Sparus aurata) of Aegean Sea were investigated. Total saturated (28.01%) and total monounsaturated (28.42%) fatty acid contents of non-irradiated decreased content of 27.69-27.97% for 2.5 kGy irradiated groups and increased content of 28.33-28.56% for 5 kGy irradiated groups after irradiation process. Total polyunsaturated fatty acid content for irradiated samples was lower than that of non-irradiated samples. Aspartic acid, glutamic acid, serine, glycine, arginine, alanine, tyrosine, cystine, tryptophan, lysine and proline contents for 2.5 and 5 kGy irradiated sea bream are significantly different ( p<0.05).

Erkan, Nuray; Özden, Özkan

2007-10-01

202

Effects of benzoic and cinnamic acids on growth, mineral composition, and chlorophyll content of soybean  

Microsoft Academic Search

Organic acids are major water-soluble allelochemicals found in soil infested with quackgrass and are involved in several processes that are important in plant growth and development. This study was carried out to gain more information on the effects of benzoic acid (BEN) andtrans-cinnamic acid (CIN) on growth, mineral composition, and chlorophyll content of soybean [Glycine max (L.) Merr. cv. Maple

R. Baziramakenga; R. R. Simard; G. D. Leroux

1994-01-01

203

Influence of growth conditions on fatty acid composition of a polyunsaturated-fatty-acid-producing Vibrio species  

Microsoft Academic Search

The influence on fatty acid composition of growth medium composition and phase of growth during batch culture and of dilution\\u000a rate and growth temperature during continuous culture was studied in the eicosapentaenoic-acid (20:5 n-3)-producing Vibrio CCUG 35308. In glucose-mineral medium, even-numbered normal fatty acyl residues, primarily 16:0, 16:1, 18:1, and 20:5, strongly\\u000a dominated (ca. 90%), and the fatty acid profile

Jens-Petter Jøstensen; Bjarne Landfald

1996-01-01

204

One-Pot Synthesis of Diverse dl-Configuration Dipeptides by a Streptomyces d-Stereospecific Amidohydrolase ? †  

PubMed Central

The synthesis of diverse dl-configuration dipeptides in a one-pot reaction was demonstrated by using a function of the aminolysis reaction of a d-stereospecific amidohydrolase from Streptomyces sp., a clan SE, S12 family peptidase categorized as a peptidase with d-stereospecificity. The enzyme was able to use various aminoacyl derivatives, including l-aminoacyl derivatives, as acyl donors and acceptors. Investigations of the specificity of the peptide synthetic activity revealed that the enzyme preferentially used d-aminoacyl derivatives as acyl donors. In contrast, l-amino acids and their derivatives were preferentially used as acyl acceptors. Consequently, the synthesized dipeptides had a dl-configuration when d- and l-aminoacyl derivatives were mixed in a one-pot reaction. This report also describes that the enzyme produced cyclo(d–Pro-l-Arg), a specific inhibitor of family 18 chitinase, with a conversion rate for d-Pro benzyl ester and l-Arg methyl ester to cyclo(d-Pro–l-Arg) of greater than 65%. Furthermore, based on results of cyclo(d-Pro–l-Arg) synthesis, we propose a reaction mechanism for cyclo(d-Pro–l-Arg) production.

Arima, Jiro; Usuki, Hirokazu; Hatanaka, Tadashi; Mori, Nobuhiro

2011-01-01

205

Serum Paraoxonase 1 Activity Is Associated with Fatty Acid Composition of High Density Lipoprotein  

PubMed Central

Introduction. Cardioprotective effect of high density lipoprotein (HDL) is, in part, dependent on its related enzyme, paraoxonase 1 (PON1). Fatty acid composition of HDL could affect its size and structure. On the other hand, PON1 activity is directly related to the structure of HDL. This study was designed to investigate the association between serum PON1 activity and fatty acid composition of HDL in healthy men. Methods. One hundred and forty healthy men participated in this research. HDL was separated by sequential ultracentrifugation, and its fatty acid composition was analyzed by gas chromatography. PON1 activity was measured spectrophotometrically using paraxon as substrate. Results. Serum PON1 activity was directly correlated with the amount of stearic acid and dihomo-gamma-linolenic acid (DGLA). PON1/HDL-C was directly correlated with the amount of miristic acid, stearic acid, and DGLA and was inversely correlated with total amount of ?6 fatty acids of HDL. Conclusion. The fatty acid composition of HDL could affect the activity of its associated enzyme, PON1. As dietary fats are the major determinants of serum lipids and lipoprotein composition, consuming some special dietary fatty acids may improve the activity of PON1 and thereby have beneficial effects on health.

Boshtam, Maryam; Pourfarzam, Morteza; Ani, Mohsen; Naderi, Gholam Ali; Basati, Gholam; Mansourian, Marjan; Dinani, Narges Jafari; Asgary, Seddigheh; Abdi, Soheila

2013-01-01

206

Ligands for the tyrosine kinase p56lck SH2 domain: discovery of potent dipeptide derivatives with monocharged, nonhydrolyzable phosphate replacements.  

PubMed

p56lck is a member of the src family of tyrosine kinases. Through modular binding units called SH2 domains, p56lck promotes phosphotyrosine-dependent protein-protein interactions and plays a critical role in signal transduction events that lead to T-cell activation. Starting from the phosphorylated dipeptide (2), a high-affinity ligand for the p56lck SH2 domain, we have designed novel dipeptides that contain monocharged, nonhydrolyzable phosphate group replacements and bind to the protein with KD's in the low micromolar range. Replacement of the phosphate group in phosphotyrosine-containing sequences by a (R/S)-hydroxyacetic (compound 8) or an oxamic acid (compound 10) moiety leads to hydrolytically stable, monocharged ligands, with 83- and 233-fold decreases in potency, respectively. This loss in binding affinity can be partially compensated for by incorporating large lipophilic groups at the inhibitor N-terminus. These groups provide up to 13-fold increases in potency depending on the nature of the phosphate replacement. The discovery of potent (2-3 microM), hydrolytically stable dipeptide derivatives, bearing only two charges at physiological pH, represents a significant step toward the discovery of compounds with cellular activity and the development of novel therapeutics for conditions associated with undesired T-cell proliferation. PMID:10346928

Beaulieu, P L; Cameron, D R; Ferland, J M; Gauthier, J; Ghiro, E; Gillard, J; Gorys, V; Poirier, M; Rancourt, J; Wernic, D; Llinas-Brunet, M; Betageri, R; Cardozo, M; Hickey, E R; Ingraham, R; Jakes, S; Kabcenell, A; Kirrane, T; Lukas, S; Patel, U; Proudfoot, J; Sharma, R; Tong, L; Moss, N

1999-05-20

207

Effects of the phi[NHCO] retromodification on dehydroalanine dipeptide.  

PubMed

The potential energy surface of the phi [NHCO] delta Ala dipeptide has been computed using ab initio quantum mechanical calculations at different theoretical levels. Three degenerate minima were found and characterized. The most favoured conformation is stabilized by an intramolecular hydrogen bonding interaction. The other two minima correspond to helical and malonamide-like conformations, being 4.6 kcal/mol and 6.9 kcal/mol less stable than the lowest energy conformation, respectively. Influence of solvent effects on the relative stabilities of the different conformations have been accounted using SCRF calculations. Two implicit solvent models have been considered: water and CCl4. The results indicate that in the both cases the conformation with an intramolecular hydrogen bonding interaction retains its lowest energy. PMID:8913855

Alemán, C

1996-10-01

208

Inhibition of the growth of transformed and neoplastic cells by the dipeptide carnosine.  

PubMed

Human diploid fibroblasts growth normally in medium containing physiological concentrations of the naturally occurring dipeptide carnosine (beta-alanyl-L-histidine). These concentrations are cytotoxic to transformed and neoplastic cells lines in modified Eagle medium (MEM), whereas these cells grow vigorously in Dulbecco's modified Eagle medium (DMEM) containing carnosine. This difference is due to the presence of 1 mM sodium pyruvate in DMEM. Seven human cell lines and two rodent cell lines were tested and all are strongly inhibited by carnosine in the absence of pyruvate. Experiments with HeLa cells show that anserine is similar to carnosine, but D-carnosine and homocarnosine are without effect. Also, the non-essential amino acids alanine and glutamic acid contribute to the effect of pyruvate in preventing carnosine toxicity, and oxaloacetate and alpha-ketoglutarate can substitute for pyruvate. We have used mixtures of normal MRC-5 fibroblasts and HeLa cells to demonstrate that 20 mM carnosine can selectively eliminate the tumour cells. This has obvious implications which might be exploited in in vivo and in vitro studies. Carnosine is known to react strongly with aldehyde and keto groups of sugars by Amadori reaction, and we propose that it depletes certain glycolysis intermediates. It is well known that tumour cells are more dependent on glycolysis than normal cells. A reduction of glycolysis intermediates by carnosine may deplete their energy supply, but this effect is totally reversed by pyruvate. PMID:8611433

Holliday, R; McFarland, G A

1996-04-01

209

Composition of amino acids in feed ingredients for animal diets.  

PubMed

Dietary amino acids (AA) are crucial for animal growth, development, reproduction, lactation, and health. However, there is a scarcity of information regarding complete composition of "nutritionally nonessential AA" (NEAA; those AA which can be synthesized by animals) in diets. To provide a much-needed database, we quantified NEAA (including glutamate, glutamine, aspartate, and asparagine) in feed ingredients for comparison with "nutritionally essential AA" (EAA; those AA whose carbon skeletons cannot be formed by animals). Except for gelatin and feather meal, animal and plant ingredients contained high percentages of glutamate plus glutamine, branched-chain AA, and aspartate plus asparagine, which were 10-32, 15-25, and 8-14% of total protein, respectively. In particular, leucine and glutamine were most abundant in blood meal and casein (13% of total protein), respectively. Notably, gelatin, feather meal, fish meal, meat and bone meal, and poultry byproduct had high percentages of glycine, proline plus hydroxyproline, and arginine, which were 10-35, 9.6-35, and 7.2-7.9% of total protein, respectively. Among plant products, arginine was most abundant in peanut meal and cottonseed meal (14-16% of total protein), whereas corn and sorghum had low percentages of cysteine, lysine, methionine, and tryptophan (0.9-3% of total protein). Overall, feed ingredients of animal origin (except for gelatin) are excellent sources of NEAA and EAA for livestock, avian, and aquatic species, whereas gelatin provides highest amounts of arginine, glycine, and proline plus hydroxyproline. Because casein, corn, soybean, peanut, fish, and gelatin are consumed by children and adults, our findings also have important implications for human nutrition. PMID:20842395

Li, Xilong; Rezaei, Reza; Li, Peng; Wu, Guoyao

2011-04-01

210

[The cellular fatty acid composition of bacteria in the family Vibrionaceae].  

PubMed

It is shown that strains of Vibrio cholerae of serovar O1, biovar eltor, subtype Ogawa, museum strains V. cholerae of serovar O1 and NAG-vibrios (isolated from various sources: sea, river and sewage water, canal water and people) possess identical composition of cell fatty acids with prevailing hexadecenoic, hexadecanoic and octadecenoic acids. Being identical, fatty acid profiles of V. parahaemolyticus and V. alginolyticus, are close to that of V. cholerae differing from the latter mainly by the higher content of dodecanoic acid. Similarity of Aeromonas sp. and Vibrio strains in the fatty acid composition proves phylogenetic relation-ship of these bacteria. Fatty acid composition of Plesiomonas shigelloides cells characterized by the presence of methylenhexadecanoic acid as well as by similarity with Vibrio and Aeromonas by the content of most fatty acids confirms a supposition of R. R. Colwell on the intermediate status of genus Plesiomonas between the families Enterobacteriaceae and Vibrionaceae. Independent of the growth medium, the strains Vibrio. Aeromonas and Plesiomonas preserved a fatty-acid profile, inherent in them, with variations mainly in the content of fatty acids with the odd number of carbon atoms. Allowing for relative stability of fatty acid composition and its peculiarity in certain taxonomic groups of the studied bacteria, the above test may be used as additional objective criterion to identify the representatives of Vibrionaceae family. PMID:9044701

Vasiurenko, Z P; Padchenko, A G; Ruban, N M; Alekseenko, V V; Dobroshtan, E V; Gurleva, G G; Opanasenko, I S

1996-01-01

211

Effect of acute nitrogen dioxide exposure on the composition of fatty acid associated with phospholipids in alveolar lavage  

SciTech Connect

In vivo exposure of rats to 10 ppm nitrogen dioxide (NO/sub 2/) for 12 h caused changes in fatty acids composition of alveolar lavage phospholipids. Among the fatty acid species, the relative ratio of palmitic acid, myristic acid and palmitoleic acid increased significantly. While the relative ratio of stearic acid, oleic acid, linoleic acid and arachidonic acid decreased significantly. Both the increase in the incorporation of palmitic acid in phosphatidylcholine which would be released into the alveoli and the increase in the release of phosphatidylcholine into the alveoli may account for the changes in the fatty acid composition of the present findings.

Kobayashi, T.; Noguchi, T.; Kikuno, M.; Kubota, K.

1984-01-01

212

A comparative study of the fatty acid composition of prochloron lipids  

NASA Technical Reports Server (NTRS)

The chemical analysis of lipids of Prochloron isolated from several hosts is discussed. The object was to determine whether differences in lipid composition could be used to characterize organisms from different sources. Major lipid components are given. An analysis of fatty acid composition of individual lipids slowed a distinctive disstribution of fatty acids. While present results do not justify the use of fatty acid content in the taxonomy of Prochlon, the variations found in the lipids of cells from the same host harvested from different areas, or at different times in the same area, suggest that a study of the effects of temperature and light intensity on lipid composition would be rewarding.

Kenrick, J. R.; Deane, E. M.; Bishop, D. G.

1983-01-01

213

Compositions and Methods Relating to Nucleic Acid Reference Standards.  

National Technical Information Service (NTIS)

The invention relates to novel nucleic acid reference standards comprising a nucleic acid comprising a known target sequence bound with a microparticulate binding agent where the binding agent includes liposomes, polyamines (e.g., nylon), siliceous compou...

C. A. Rundell J. Gordon

2004-01-01

214

Compositions and Methods for Systemic Nucleic Acid Sequence Delivery.  

National Technical Information Service (NTIS)

The present invention provides systemic nucleic acid sequence delivery without conventional systemic administration aids (SAAs). In certain embodiments, vascular permeability agents (VPAs), such as VEGF, are used in conjunction with nucleic acid viral vec...

J. M. Allen J. S. Chamberlain M. J. Blankinship P. Gregorevic

2004-01-01

215

Site-specific differences in the fatty acid composition of human adipose tissue  

Microsoft Academic Search

The fatty acid composition of triacylglycerols from fifteen distinct adipose depots taken from each of seven adult male human\\u000a subjects was compared. Oleic, palmitic, linoleic, stearic, myristic, palmitoleic and vaccenic acids accounted for more than\\u000a 90% of the triacylglycerol fatty acids in all sites from all subjects; a number of other fatty acids were also identified\\u000a and quantified. There were

P. C. Calder; D. J. Harvey; C. M. Pond; E. A. Newsholme

1992-01-01

216

Organic acid, tocopherol, and phenolic compositions of some Turkish grape cultivars  

Microsoft Academic Search

The organic acid, tocopherol, and phenolic compositions of three different grape cultivars, Emir, Kalecik karasi, and Narince\\u000a were studied in order to evaluate their nutritive values and the contents of natural antioxidants. Organic acids, tocopherols,\\u000a phenolic acids, flavonoids, and trans-resveratrol contents were analyzed by high-performance liquid chromatography (HPLC). In addition, pH, soluble solid, titratable\\u000a acidity, and total phenolic contents were

Nilgun Gokturk Baydar

2006-01-01

217

Sulfonated mesoporous silica-carbon composites and their use as solid acid catalysts  

NASA Astrophysics Data System (ADS)

The synthesis of highly functionalized porous silica-carbon composites made up of sulfonic groups attached to a carbon layer coating the pores of three types of mesostructured silica (i.e. SBA-15, KIT-6 and mesocellular silica) is presented. The synthesis procedure involves the following steps: (a) removal of the surfactant, (b) impregnation of the silica pores with a carbon precursor, (c) carbonization and (d) sulfonation. The resulting silica-carbon composites contain ˜30 wt % of carbonaceous matter with a high density of acidic groups attached to the deposited carbon (i.e.sbnd SO3H, sbnd COOH and sbnd OH). The structural characteristics of the parent silica are retained in the composite materials, which exhibit a high surface area, a large pore volume and a well-ordered porosity made up uniform mesopores. The high density of the sulfonic groups in combination with the mesoporous structure of the composites ensures that a large number of active sites are easily accessible to reactants. These sulfonated silica-carbon composites behave as eco-friendly, active, selective, water tolerant and recyclable solid acids. In this study we demonstrate the usefulness of these composites as solid acid catalysts for the esterification of maleic anhydride, succinic acid and oleic acid with ethanol. These composites exhibit a superior intrinsic catalytic activity to other commercial solid acids such as Amberlyst-15.

Valle-Vigón, Patricia; Sevilla, Marta; Fuertes, Antonio B.

2012-11-01

218

Some applications of deoxyribonucleic acid base composition in bacterial taxonomy  

Microsoft Academic Search

The “melting point”Tm, the mean molar (guanine+cytosine) composition and the compositional distribution of purified DNA from several strains ofXanthomonas, Chromobacterium and yellow-pigmented marine bacteria have been determined. These groups were selected because they had been analyzed adansonially. Ten strains ofXanthomonas had an average molar (guanine+cytosine) composition within the range 66.0–68.2%, which was very close to that ofPseudomonas (60–68%), as expected.

J. De Ley; J. Van Muylem

1963-01-01

219

"Click dipeptide": a novel stationary phase applied in two-dimensional liquid chromatography.  

PubMed

2D-HPLC is an important technique for the separation of complex samples. Developing new types of stationary phases is of great interest to construct 2D-LC systems with high orthogonality. In this study, a novel stationary phase-Click dipeptide (l-phenylglycine dipeptide) was prepared by immobilization of alpha-azido l-phenylglycine dipeptide on alkyne-silica via click chemistry. In the preparation of this new material, an efficient, inexpensive and shelf-stable diazo transfer reagent (imidazole-1-sulfonyl azide hydrochloride) was utilized to transfer the amino group of l-phenylglycine to corresponding azido group under mild conditions. The Click dipeptide thus prepared was confirmed by FT-IR, solid state CP/MAS (13)C NMR and elemental analysis. The Click dipeptide packing showed high orthogonality with C18, which reached 63.5%. An off-line 2D-RP/RPLC system was developed to analyze a traditional Chinese medicine (TCM)-Rheum Palmatum L. The results showed high orthogonality between Click dipeptide and C18 as well as great separating power in the practical separation of complex samples. PMID:19863966

Xue, Meiyun; Huang, Hongxue; Ke, Yanxiong; Chu, Changhu; Jin, Yu; Liang, Xinmiao

2009-12-01

220

Conformational characteristics of the N-acetyl-N'-methylamides of the four (Lys, Tyr) dipeptides.  

PubMed

The conformational properties of the N-acetyl-N'-methylamides of the dipeptides lysyl-lysine, lysyl-tyrosine, tyrosyl-lysine, and tyrosyl-tyrosine were studied by means of conformational energy calculations, by n.m.r. measurements in deuterated dimethylsulfoxide, and by circular dichroism in water, methanol, dioxane-water, and trifluoroethanol. Since these four dipeptides occur occasionally as bends in proteins, it was of interest to see whether short-range interactions, acting within the terminally blocked dipeptides, are sufficient to stabilize bend conformations significantly over other conformations. It was found that the four dipeptides exist as ensembles of conformations in solution. Therefore, it appears that longer-range interactions, such as those present in proteins, are required if bend conformations of these dipeptide sequences are to exist as stable conformations. Three of the dipeptides behave rather similarly. Both the CD and the n.m.r. experiments and computations indicate that the fourth (Lys-Tyr) differs from the others. It has a preference for compact conformations that appear to be stabilized by strong favorable interactions, primarily hydrogen bonds, between the tyrosyl and the lysyl side chains. The computations suggest that the presence of these interactions, and hence the existence of preferred conformations, is strongly solvent-dependent, and that these interactions are weakened in aqueous solution. PMID:7309363

Rae, I D; Leach, S J; Minasian, E; Smith, J A; Zimmerman, S S; Weigold, J A; Hodes, Z I; Némethy, G; Woody, R W; Scheraga, H A

1981-05-01

221

Changes in lipid composition, fatty acid profile and lipid oxidative stability during Cantonese sausage processing.  

PubMed

Lipid composition, fatty acid profile and lipid oxidative stability were evaluated during Cantonese sausage processing. Free fatty acids increased with concomitant decrease of phospholipids. Total content of free fatty acids at 72 h in muscle and adipose tissue was 7.341 mg/g and 3.067 mg/g, respectively. Total amount of saturated, monounsaturated and polyunsaturated fatty acids (SFA, MUFA, and PUFA) in neutral lipid exhibited a little change during processing, while the proportion of PUFA significantly decreased in the PL fraction. The main triacylglycerols were POO+SLO+OOO, PSO (P = palmitic acid, O = oleic acid, L = linoleic acid, S = stearic acid), and a preferential hydrolysis of palmitic, oleic and linoleic acid was observed. Phosphatidylcholines (PC) and phosphatidylethanolamines (PE) were the main components of phospholipids and PE exhibited the most significant degradation during processing. Thiobarbituric acid values (TBARS) increased while peroxide values and hexanal contents varied during processing. PMID:23273460

Qiu, Chaoying; Zhao, Mouming; Sun, Weizheng; Zhou, Feibai; Cui, Chun

2013-03-01

222

Effects of thermal acclimation on tissue fatty acid composition of freshwater alewives (Alosa pseudoharengus).  

PubMed

In this study, we examine changes in fatty acid composition of polar and neutral lipids in gill, liver, and muscle of freshwater alewives (Alosa pseudoharengus) after temperature challenges in the laboratory. Alewives experienced either a warm or cold challenge in which temperatures were raised or lowered 0.5°C day(-1) over 4-6 weeks. In alewives experiencing the cold challenge, gill polar lipids showed evidence of significant remodeling, including decreases in palmitic acid and saturated fatty acids and increases in n-3 and n-6 highly unsaturated fatty acids including docosahexaenoic acid (DHA) and arachidonic acid. In alewives experiencing the warm challenge, we observed significant increases in saturated fatty acids (due mainly to increased palmitic acid) and decreases in polyunsaturated fatty acids in polar lipids of muscle and liver tissue. Fish that died during the cold challenge had significantly higher levels of palmitic acid in muscle polar lipids compared to fish that survived; fish that died during the warm challenge displayed complex changes in fatty acid composition. Based on theoretical considerations, the changes in polar lipids we observed during thermal acclimation are likely to promote appropriate membrane fluidity under each thermal regime. The increased incorporation of highly unsaturated fatty acids during cold acclimation could have significant physiological and ecological implications. In particular, since highly unsaturated fatty acids are typically scarce in freshwater food webs, dietary deficiencies in these essential fatty acids may be a significant factor in winter mortality of freshwater alewives. PMID:21638009

Snyder, Randal J; Schregel, William D; Wei, Yuanhong

2012-04-01

223

Amino Acid Composition and C-Terminal Residues of Algal Biliproteins.  

National Technical Information Service (NTIS)

R-phycoerythrin from Ceramium rubrum and C-phycocyanin from Nostoc nuscorum were obtained in purified form by fractional crystallization, followed by chromatography and gel-filtration. The amino acid composition of both chromoproteins was determined; 85% ...

M. A. Raftery C. O. hEocha

1964-01-01

224

Process for Preserving Raw Fruits and Vegetables Using Ascorbic Acid Esters and Compositions Thereof.  

National Technical Information Service (NTIS)

The invention relates to the preservation of raw fruits, vegetables and their juices. More particularly, the invention relates to the use of certain ascorbic acid esters, and compositions thereof, to control enzymatic browning in raw fruit and vegetable p...

G. M. Sapers K. B. Hicks P. A. Seib

1987-01-01

225

Process for Preserving Raw Fruits and Vegetables Using Ascorbic Acid Esters and Compositions Thereof.  

National Technical Information Service (NTIS)

The present invention relates to the preservation of raw fruits, vegetables and their juices. More particularly, the present invention relates to the use of certain ascorbic acid esters, and compositions thereof, to control enzymatic browning in raw fruit...

G. M. Sapers K. B. Hicks P. A. Seib

1987-01-01

226

Superabsorbent hydrogel composite made of cellulose nanofibrils and chitosan- graft-poly(acrylic acid)  

Microsoft Academic Search

Superabsorbent hydrogel composites based on cellulose nanofibrils and chitosan-graft-poly(acrylic acid) copolymer were developed in this work. The FTIR data showed that the copolymerization and the composite formation reaction were successfully performed. In addition, the XRD pattern indicated that the nanofibrils crystallinity was as high as 90%. A 24?1 fractional factorial design was employed to evaluate the effect of acrylic acid\\/chitosan

Cristiane Spagnol; Francisco H. A. Rodrigues; Antonio G. B. Pereira; André R. Fajardo; Adley F. Rubira; Edvani C. Muniz

227

Biopolymer produced by fermenting the extract of soybean with folic acid and a composition containing thereof  

US Patent & Trademark Office Database

Provided are a folyl extract of fermented soybean (EFS) produced by fermenting a culture including a folic acid and soybean extract by using a microorganism, and a composition including the folyl EFS. The folyl EFS has an anti-histamine effect, an anti-allergic effect, a calcium-absorption-promotion effect, a bone-growth-promotion effect, a cell growth promotion effect, a collagen biosynthesis promotion effect, a wrinkle improvement effect, and an UV-induced cell damage inhibition effect. Accordingly, the folyl EFS can be used in a skin external application or cosmetic composition, a health supplement food composition, a feed composition, and a pharmaceutical composition.

2013-04-30

228

Risk of Colorectal Cancer Is Linked to Erythrocyte Compositions of Fatty Acids as Biomarkers for Dietary Intakes of Fish, Fat, and Fatty Acids  

Microsoft Academic Search

Consumption of fish rich in n-3 polyunsaturated fatty acids (PUFAs), such as docosahexaenoic acid, is suggested to reduce colorectal cancer risk through inhibition ofthe arachidonic acid (AA) cascade related to tumorigenesis and cell prolifer- ation. High intake ofsaturated fatty acids (SFAs) may increase the risk. To examine associations between colorectal cancer risk and fatty acid compositions in erythrocyte membranes, as

Kiyonori Kuriki; Kenji Wakai; Kaoru Hirose; Keitaro Matsuo; Hidemi Ito; Takeshi Suzuki; Toshiko Saito; Yukihide Kanemitsu; Takashi Hirai; Tomoyuki Kato; Masae Tatematsu; Kazuo Tajima

229

The pyrogenicity of the synthetic adjuvant muramyl dipeptide and two structural analogues.  

PubMed

The pyrogenic efect of the synthetic adjuvant N-acetylmuramyl-L-alanine-D-isoglutamine, also known as muramyl dipeptide (MDP), was studied in rabbits. MDP induced biphasic fevers in rabbits, but two structural analogues, N-acetylmuramyl-L-alanine-D-glutamic acid (MDPA) and the dimethylester of MDPA, were 10 times less pyrogenic. This finding was supported by studies in which MDP and its analogues released leukocytic pyrogen (LP) from rabbit phagocytic cells in vitro. In addition, MDP released LP from human phagocytes. Human phagocytes, however, required a 10-fold greater concentration of MDP than did rabbit cells. The structural analogues were similarly less effective than the parent molecule in releasing LP from human cells. All preparations of MDP were negative in the limulus amebocyte lysate test and failed to show pyrogenic cross-tolerance with bacterial endotoxin. Thus MDP, which is a pyrogenic molecule, is also able to release LP from rabbit phagocytes and to a lesser degree from human phagocytes, but does not cause gelation of limulus amebocyte lysate. PMID:368262

Dinarello, C A; Elin, R J; Chedid, L; Wolff, S M

1978-12-01

230

Biosynthesis of poly(?-glutamic acid) in Bacillus subtilis NX-2: Regulation of stereochemical composition of poly(?-glutamic acid)  

Microsoft Academic Search

The stereochemical composition of poly(?-glutamic acid), ?-PGA, produced by Bacillus subtilis NX-2 could be effected by Mn2+ in the culture medium. When the concentration of Mn2+ varied from 0 to 0.09g\\/l, the proportion of d-glutamate increased from 18 to 77%. The d-amino acid aminotransferase and the glutamate racemase activity were also analyzed with Mn2+ concentration changing in this range, the

Qun Wu; Hong Xu; Lin Xu; Pingkai Ouyang

2006-01-01

231

Influence of Fatty Acid Profile of Total Parenteral Nutrition Emulsions on the Fatty Acid Composition of Different Tissues of Piglets  

Microsoft Academic Search

Total parenteral nutrition (TPN) studies in human babies of very-low-birth-weight suggest that the lipid emulsions currently\\u000a available are not optimum for neonatal nutrition. Since fatty acid metabolism in human and pigs is very similar, the present\\u000a study examines how lipid emulsions used in clinical TPN (i.e. ClinOleic, Intralipid, Lipofundin or Omegaven), with different\\u000a fatty acid compositions, administered to neonatal piglets

E. Amusquivar; M. Sánchez; M. J. Hyde; J. Laws; L. Clarke; E. Herrera

2008-01-01

232

Graphene-carbon nanotube composite aerogel for selective detection of uric acid  

NASA Astrophysics Data System (ADS)

Graphene and single-walled carbon nanotube (SWNT) composite aerogel has been prepared by hydrothermal synthesis. The restacking of graphene is effectively reduced by SWNTs inserted in between graphene layers in order to make available more active sites and reactive surface area. Electrochemical experiments show that the graphene-SWNT composite electrode has superior catalytic performance in selective detection of uric acid (UA).

Zhang, Feifei; Tang, Jie; Wang, Zonghua; Qin, Lu-Chang

2013-12-01

233

Investigation of PEMFC operation above 100 °C employing perfluorosulfonic acid silicon oxide composite membranes  

Microsoft Academic Search

Various perfluorosulfonic acid membranes (PFSAs) were studied as pure and silicon oxide composite membranes for operation in hydrogen\\/oxygen proton-exchange membrane fuel cells (PEMFCs) from 80 to 140°C. The composite membranes were prepared either by impregnation of pre-formed PFSAs via sol–gel processing of a polymeric silicon oxide, recasting a film using solubilized PFSAs and a silicon oxide polymer\\/gel. All composite membranes

K. T Adjemian; S Srinivasan; J Benziger; A. B Bocarsly

2002-01-01

234

Viscoelastic and thermal behavior of woven hemp fiber reinforced poly(lactic acid) composites  

Microsoft Academic Search

This study examined the physical behavior of hemp\\/poly(lactic acid) (PLA) composites, particularly the thermal properties and viscoelastic behavior. Twill and plain woven hemp fabrics were used as reinforcements and hemp fabrics-reinforced PLA composites were produced using a film stacking method. The coefficient of thermal expansion of the composites decreased sharply with increasing the volume fraction of fiber. The twill structure

Young Seok Song; Jung Tae Lee; Ji Dong Sun; Myung Wook Kim; Seung Hwan Lee; Jae Ryoun Youn

235

Amino Acid Composition and In Vitro Protein Digestibility of Selected Ancient Wheats and their End Products  

Microsoft Academic Search

The total protein, amino acid composition and in vitro protein digestibility of selected ancient wheats and their pasta, breakfast cereal and bread products were determined and compared with those produced from durum and common wheat. The protein values in the whole meals varied among wheats with einkorn and hard spelt having the highest content (17.7%). Slight differences in amino acid

E.-S. M. Abdel-Aal; P. Hucl

2002-01-01

236

Cesium sorption from concentrated acidic tank wastes using ammonium molybdophosphate-polyacrylonitrile composite sorbents  

Microsoft Academic Search

Ammonium molybdophosphate-polyacrylonitrile (AMP-PAN) composite sorbents have been evaluated for the removal of cesium from Idaho National Engineering and Environmental Laboratory (INEEL) concentrated acidic tank waste. Batch contacts were performed to qualitatively evaluate the effects of increased nitric acid, sodium and potassium. An equilibrium isotherm was generated with simulated concentrated tank waste solutions and fit to the Langmuir equation. Additional batch

T. A. Todd; N. R. Mann; T. J. Tranter; F. Šebesta; J. John; A. Motl

2002-01-01

237

Membrane Lipid Composition of Pancreatic AR42J Cells: Modification by Exposure to Different Fatty Acids  

Microsoft Academic Search

Dietary fat type influences fatty acids in rat pancreatic membranes, in association with modulation of secretory activity and cell signalling in viable acini. We aimed to confirm whether AR42J cells are a valid model to study the interactions between lipids and pancreatic acinar cell function. For this purpose we have (i) compared the baseline fatty acid composition of AR42J cells

NAMA' A AUDI; MARIA D. MESA; MARIA A. MARTINEZ; EMILIO MARTINEZ-VICTORIA; MARIANO MANAS; MARIA D. YAGO

2007-01-01

238

Removal of gases by thermal-acid leached kaolinitic clays: Influence of mineralogical composition  

Microsoft Academic Search

Natural and modified kaolinitic clays were used as retention for gas adsorptions. The kaolinitic clays containing different mineralogical compositions were used. The modifications were carried out by heating the clays at 600 °C and then by acid treatment with 2.5 mol\\/L sulphuric acid solution at boiling temperature for 180 min. Equilibrium adsorption was measured using a volumetric apparatus, at 25

Cristina Volzone; José Ortiga

2006-01-01

239

Fatty acid composition of the tropical lichen Teloschistes flavicans and its cultivated symbionts.  

PubMed

Fatty acid components, in both the free and combined form of the intact tropical lichen Teloschistes flavicans, and its isolated photobiont and mycobiont, were analyzed by GC-MS of derived methyl esters. Its rDNA analysis confirmed that the isolated cultured symbionts belong to the genera Trebouxia and Teloschistes, respectively. The fatty acid composition of the lichen did not correspond to those found in the isolated symbionts, suggesting that the fatty acid metabolism is markedly influenced by the symbiosis. Differences in the fatty acid composition in the lichen were observed during the summer (27 degrees C), when the main fatty acids were saturated and in the winter (22 degrees C) when an increase of unsaturated fatty acids occurred. Similar differences of composition were also observed for the cultured mycobiont at different temperatures. The increase in the unsaturation level at low temperatures would maintain the membrane fluidity. Our results are the first on the fatty acids of a tropical lichen and suggest that it is sensitive to small temperature variations, which influences its saturated and unsaturated fatty acid composition. PMID:15927741

Reis, Rodrigo Arantes; Iacomini, Marcello; Gorin, Philip Albert James; de Souza, Lauro Mera; Grube, Martin; Cordeiro, Lucimara Mach Cortes; Sassaki, Guilherme Lanzi

2005-06-01

240

Effect of Plant Nutrition on the Amino-Acid Composition of Wheat Proteins.  

National Technical Information Service (NTIS)

Conditions of nitrogen and potassium-phosphorus nutrition of plants have a substantial effect on the amino-acid composition of protein substances in wheat. With a nitrate source of nitrogen, the content of the aromatic amino acids tryptophan and tyrosine ...

I. A. Poltavskaya

1965-01-01

241

[The study of biologically active conformation of cholecystokinin-4 dipeptide analog GB-115].  

PubMed

The conformational analysis with 1H NMR spectroscopy method in solution and the structure-activity relationship study of a series sterically restricted analogs allowed to detect the possible biologically active conformation of N-(6-phenylhexanoyl)glycyl-tryptophan amide (GB-115), a highly active dipeptide cholecystokinin-4 analog with anxiolytic activity. The structure-activity relationship study of GB-115 and the series of its' glycine- and proline-containing analogs with different C-terminal substitute detected the anxiolytic activity of compounds with beta-turn like conformation and inactivity of compounds with gamma-turn like conformation. So, the GB-115 biologically active conformation is beta-turn. The results of nuclear Overhauser effect study permitted to qualify the betaII-turn conformation as GB-115 biologically active conformation. The following synthesis of sterically restricted GB-115 analogs (2S)-2-{(3R)-3-[(6-phenylhexanoyl)amino]-2-oxopyrrolidin-1-yl}-3-(1H-indol-3-yl)propionic acid ethyl ester, N-(6-phenylhexanoyl)glycyl-N(alpha)(methyl)-tryptophan ethyl ester, (2S)-2-[10,11-dihydro-5H-dibenzo[b,f] azepin-5-carbonyl)-amino]-3-(1H-indol-3-yl)propionic acid methyl ester and (2S)-2-[({3-[(ethoxycarbonyl)amino]-10,11-dihydro-5H-dibenzo[b,f]azepin-5-yl}carbonyl)amino]-3-(1H-indol-3-yl)propionic acid methyl ester confirmed the estimated type of GB-115 biologically active conformation. PMID:24397028

Gudasheva, T A; Lezina, V P; Kir'ianova, E P; Deeva, O A; Kolik, L G; Seredenin, S B

2013-01-01

242

The Amino Acid Composition of the Sutter's Mill Carbonaceous Chondrite  

NASA Technical Reports Server (NTRS)

In contrast to the Murchison meteorite which had a complex distribution of amino acids with a total C2 to Cs amino acid abundance of approx.14,000 parts-per-billion (ppb) [2], the Sutters Mill meteorite was found to be highly depleted in amino acids. Much lower abundances (approx.30 to 180 ppb) of glycine, beta-alanine, L-alanine and L-serine were detected in SM2 above procedural blank levels indicating that this meteorite sample experienced only minimal terrestrial amino acid contamination after its fall to Earth. Carbon isotope measurements will be necessary to establish the origin of glycine and beta-alanine in SM2. Other non-protein amino acids that are rare on Earth, yet commonly found in other CM meteorites such as aaminoisobutyric acid (alpha-AIB) and isovaline, were not identified in SM2. However, traces of beta-AIB (approx.1 ppb) were detected in SM2 and could be" extraterrestrial in origin. The low abundances of amino acids in the Sutter's Mill meteorite is consistent with mineralogical evidence that at least some parts of the Sutter's Mill meteorite parent body experienced extensive aqueous and/or thermal alteration.

Glavin, D. P.; Burton, A. S.; Elsila, J. E.; Dworkin, J. P.; Yin, Q. Z.; Cooper, G.; Jenniskens, P.

2012-01-01

243

Sensitive Amino Acid Composition and Chirality Analysis with the Mars Organic Analyzer (MOA)  

NASA Technical Reports Server (NTRS)

Detection of life on Mars requires definition of a suitable biomarker and development of sensitive yet compact instrumentation capable of performing in situ analyses. Our studies are focused on amino acid analysis because amino acids are more resistant to decomposition than other biomolecules, and because amino acid chirality is a well-defined biomarker. Amino acid composition and chirality analysis has been previously demonstrated in the lab using microfabricated capillary electrophoresis (CE) chips. To analyze amino acids in the field, we have developed the Mars Organic Analyzer (MOA), a portable analysis system that consists of a compact instrument and a novel multi-layer CE microchip.

Skelley, Alison M.; Scherer, James R.; Aubrey, Andrew D.; Grover, William H.; Ivester, Robin H. C.; Ehrenfreund, Pascale; Grunthaner, Frank J.; Bada, Jeffrey L.; Mathies, Richard A.

2005-01-01

244

Is the Fatty Acid Composition of Freshwater Zoobenthic Invertebrates Controlled by Phylogenetic or Trophic Factors?  

Microsoft Academic Search

We studied the fatty acid (FA) content and composition of ten zoobenthic species of several taxonomic groups from different\\u000a freshwater bodies. Special attention was paid to essential polyunsaturated fatty acids, eicosapentaenoic acid (EPA, 20:5n-3),\\u000a docosahexaenoic acid (DHA, 22:6n-3), and arachidonic acid (ARA, 20:4n-6); and the n-3\\/n-6 and DHA\\/ARA ratios, which are important\\u000a for consumers of higher trophic levels, i.e., fish.

Olesia N. MakhutovaNadezhda; Nadezhda N. Sushchik; Michail I. Gladyshev; Alexander V. Ageev; Ekaterina G. Pryanichnikova; Galina S. Kalachova

245

Differentiation of some positional and diastereomeric isomers of Boc-carbo-[beta]3 dipeptides containing galactose, xylose and mannose sugars by electrospray ionization tandem mass spectrometry (ESI MS/MS)  

NASA Astrophysics Data System (ADS)

Electrospray ionization (ESI) tandem mass spectrometry has been used to distinguish the positional and diastereomeric isomers of Boc-C-linked carbo-[beta]3 dipeptides (1-38) synthesized from glycine (Gly), [beta]-h-glycine ([beta]-hGly), [beta]-h-alanine ([beta]-hAla) and C-linked carbo-[beta]3-amino acid (Caa) that contain galactose, xylose and mannose sugars as side chains with "R" and "S" configurations at the amine center. The major fragmentation of [M + H]+ of the dipeptides (1-38) yields mainly two ions: (i) [M + H-C(CH3)3 + H]+ ([`]a') and (ii) [M + H-Boc + H]+ ([`]b') corresponding to losses of 2-methyl-prop-1-ene and -Boc moiety from [M + H]+ ions, respectively. The diastereomeric dipeptide isomers with Caa (R) and (S) configurations at the N-terminus can easily be distinguished by the difference in the abundance of ion [`]a' and [`]b'. The isomeric peptides with Caa (R) at the N-terminus gives prominent [M + H-C(CH3)3 + H]+ ([`]a') where as it is insignificant or totally absent for peptides which have Caa (S) at the N-terminus. This is presumably due to the different steric crowdings around the Boc-group in the different diastereomers. The positional isomers of dipeptides can also be differentiated by the difference in the abundance of ion [`]a' and [`]b' in the CID of [M + H]+ ions. The CID of [M + H-Boc + H]+ ions of the isomeric peptides also show y1+ ions at different m/z values. All these results suggest that the CID of [M + H]+ ions is highly useful for distinguishing the Boc-NH-Caa-[beta]3 dipeptide isomers with Caa of "S" configuration from the isomers with Caa of "R" configuration and the positional isomers.

Reddy, P. Nagi; Ramesh, V.; Srinivas, R.; Sharma, G. V. M.; Nagendar, Pendem; Subash, V.

2006-02-01

246

Protein Content and Amino Acid Composition in Grains of Wheat-Related Species  

Microsoft Academic Search

The protein content and amino acid composition for 17 wheat-related species (WRS) and three common wheats (control) were determined and analyzed, and the essential amino acids (EAAs) in WRS were evaluated according to FAO\\/WHO amino acid recommendations. The results showed that the mean protein content for WRS was 16.67%, which was 23.21% higher than that for the control. The mean

Xiao-ling JIANG; Ji-chun TIAN; Zhi HAO; Wei-dong ZHANG

2008-01-01

247

Amino Acid and Vitamin Composition of Raw and Cooked Horse Mackerel  

Microsoft Academic Search

Amino acid, vitamin (A, E, B1, B2, B3 and B6), and proximate composition were determined in raw and cooked horse mackerel. The changes in amino acid, vitamin, and proximate\\u000a content were found to be significant for all cooking methods (frying, grilling, and steaming). Cooking did in general significantly\\u000a increase the contents of essential, semi-essential, and other amino acids compared to

Nuray Erkan; Arif Selçuk; Özkan Özden

2010-01-01

248

Isolation and Amino Acid Composition of Ribosomal Proteins from Bacillus stearothermophilus  

PubMed Central

Twelve of the proteins from the 30S ribosome of Bacillus stearothermophilus were isolated by preparative disc electrophoresis. Amino acid analyses of these proteins showed them to be different from each other. The gross amino acid composition of 30S ribosomal protein from B. stearothermophilus and Escherichia coli are virtually identical. A number of the proteins of B. stearothermophilus had electrophoretic mobilities similar or identical to 30S ribosomal proteins of E. coli. However, there was little similarity between the two organisms in amino acid composition of individual proteins. There were no unusual chemical features of the B. stearothermophilus proteins which could explain the relative thermal stability of this organism's ribosomes. Images

Ansley, Steven B.; Campbell, L. Leon; Sypherd, Paul S.

1969-01-01

249

Dietary conjugated linoleic acid and body composition1-3  

Microsoft Academic Search

Conjugated linoleic acid (CLA) is a group of positional and geomet- ric isomers of conjugated dienoic derivatives of linoleic acid. The major dietary source of CLA for humans is ruminant meats, such as beef and lamb, and dairy products, such as milk and cheese. The major isomer of CLA in natural food is cis-9,trans-11 (c9,t11). The commercial preparations contain approximately

Yanwen Wang; Peter JH Jones

250

Composition and properties of acid tar and asphalt produced from acid tar  

Microsoft Academic Search

Acid tar is a waste material that is produced in large volumes in treating petroleum oils with concentrated sulfuric acid. The acid tar contains up to 80% petroleum oils and tars and resins. In current practice, the acid tar Ss dumped into holding ponds that take up large areas of land; this practice leads to pollution of the ground, water,

A. F. Frolov; A. N. Aminov; S. D. Timrot

1981-01-01

251

Amino acid composition of cadmium-binding protein induced in a marine diatom  

SciTech Connect

Organisms living in environments polluted with heavy metals develop tolerance against these contaminants. The tolerance has been attributed to the ability to synthesize metal binding substances. These recent findings imply metal binding complexes from animals and plants, although having very similar functional properties, may have entirely different amino acid compositions. Researchers reported that cadystin from fission yeast, Schizosaccharomyces pombe was composed of only glutamic acid, cysteine, and glycine. A year later, a heavy metal binding substance was isolated from Rauwolfia serpetina which contains only Glu, Cys, and Gly. Heavy metal binding complexes isolated from the water hyacinth and morning glory Datura innoxia also showed an amino acid composition similar to cadystin or phytochelatin. In this study, the cadmium binding protein induced in the marine diatom, Phaeodactylum tricornutum, was isolated and purified and its amino acid composition determined.

Maita, Y.; Kawaguchi, S. (Hokkaido Univ. (Japan))

1989-09-01

252

Soft glass rheology in liquid crystalline gels formed by a monodisperse dipeptide.  

PubMed

Thermal and extensive rheological characterization of a nematic liquid crystal gelated with a novel monodisperse dipeptide, also a liquid crystal, has been carried out. For certain concentrations, the calorimetric scans display a two-peak profile across the chiral nematic-isotropic (N*-I) transition, a feature reminiscent of the random-dilution to random-field crossover observed in liquid crystal gels formed with aerosil particles. All samples show shear thinning behavior without a Newtonian plateau region at lower shear rates. Small deformation oscillatory data at lower frequencies exhibit a frequency dependence of the storage (G') and loss (G'') moduli that can be described by a weak power-law, characteristic of soft glassy rheological systems. At higher frequencies, while lower concentration composites have a strong frequency dependence with a trend for possible crossover from viscoelastic solid to viscoelastic liquid behavior, the higher-concentration gels show frequency-independent rheograms of entirely elastic nature G' > G''. The plateau modulus of G' is described by a power-law with an exponent again common to soft materials, such as foams, slurries, etc. Other features which are a hallmark of such materials observed in the present study are: (i) above a critical strain, a strain softening of the moduli with a peak in the loss modulus, (ii) power-law variation of the storage modulus in the nonlinear viscoelastic regime, and (iii) absence of Cox-Merz superposition for the complex viscosity. An attractive feature of these gels is the fast recovery upon removal of large strain and qualitatively different temporal behavior of the recovery between the low and high concentration composites, with the latter indicating the presence of two characteristic time scales. PMID:20028007

Nair, Geetha G; Krishna Prasad, S; Bhargavi, R; Jayalakshmi, V; Shanker, G; Yelamaggad, C V

2010-01-21

253

Evolutionary modifications of human milk composition: evidence from long-chain polyunsaturated fatty acid composition of anthropoid milks.  

PubMed

Brain growth in mammals is associated with increased accretion of long-chain polyunsaturated fatty acids (LCPUFA) in brain phospholipids. The period of maximum accumulation is during the brain growth spurt. Humans have a perinatal brain growth spurt, selectively accumulating docosahexaenoic acid (DHA) and other LCPUFA from the third trimester through the second year of life. The emphasis on rapid postnatal brain growth and LCPUFA transfer during lactation has led to the suggestion that human milk LCPUFA composition may be unique. Our study tests this hypothesis by determining fatty acid composition for 11 species of captive anthropoids (n=53; Callithrix jacchus, Cebus apella, Gorilla gorilla, Hylobates lar, Leontopithecus rosalia, Macaca mulatta, Pan troglodytes, Pan paniscus, Pongo pygmaeus, Saimiri boliviensis, and Symphalangus syndactylus). Results are compared to previously published data on five species of wild anthropoids (n=28; Alouatta paliatta, Callithrix jacchus, Gorilla beringei, Leontopithecus rosalia, and Macaca sinica) and human milk fatty acid profiles. Milk LCPUFA profiles of captive anthropoids (consuming diets with a preformed source of DHA) are similar to milk from women on a Western diet, and those of wild anthropoids are similar to milk from vegan women. Collectively, the range of DHA percent composition values from nonhuman anthropoid milks (0.03-1.1) is nearly identical to that from a cross-cultural analysis of human milk (0.06-1.4). Humans do not appear to be unique in their ability to secrete LCPUFA in milk but may be unique in their access to dietary LCPUFA. PMID:18809203

Milligan, Lauren A; Bazinet, Richard P

2008-12-01

254

Composition of antioxidants and amino acids in Stevia leaf infusions.  

PubMed

Stevia, a non-caloric natural sweetener with beneficial properties and considerable antioxidants and amino acids, is increasingly consumed as an infusion. This work evaluates the influence of the conditions (temperature: 50, 70 or 90 °C and time: 1, 5, 20 or 40 min) applied to obtain Stevia infusions, on antioxidants (total phenols, flavonoids and antioxidant activity) and amino acids. The total concentration of the eleven amino acids found was 11.70 mg/g in dried leaves and from 6.84 to 9.11 mg/g per gram of Stevia in infusions. However, infusions showed higher levels of certain amino acids (alanine, asparagine, leucine and proline), and greater values of the three antioxidant parameters in comparison with dry leaves. Temperature had more influence (minimum values at 50 °C and maximum at 90 °C) than time in the case of antioxidants. At 90 °C there were no important increases in the extraction of antioxidant compounds after 5 min; each gram of Stevia had 117 mg trolox (total antioxidant activity), 90 mg gallic acid (total phenols) and 56 mg catechin equivalents (flavonoids). Varying the temperature and time conditions no notable differences were observed in the concentrations of the majority of amino acids. However, the infusion treatment at 90 °C for 5 min was the best, as it gave the highest yield of 8 of the 11 amino acids. Therefore, with respect to the compounds analyzed in this study, the best way to obtain Stevia leaf infusions is the same as the domestic process, almost boiling water for a short time. PMID:24293005

Periche, Angela; Koutsidis, Georgios; Escriche, Isabel

2014-03-01

255

In Vitro Antibacterial Screening of Six Proline-Based Cyclic Dipeptides in Combination with ?-Lactam Antibiotics Against Medically Important Bacteria.  

PubMed

The in vitro synergistic antibacterial activity of six proline-based cyclic dipeptides [cyclo(D-Pro-L-Leu), cyclo(L-Pro-L-Met), cyclo(D-Pro-L-Phe), cyclo(L-Pro-L-Phe), cyclo(L-Pro-L-Tyr), and cyclo(L-Pro-D-Tyr)] in combination imipenem and ceftazidime was investigated in the present manuscript. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the cyclic dipeptides were compared with those of the standard antibiotics (imipenem and ceftazidime). The synergistic antibacterial activities of cyclic dipeptides with imipenem or ceftazidime were assessed using the checkerboard and time-kill methods. The results of the present study showed that the combined effect of six cyclic dipeptides with imipenem predominantly recorded synergistic interaction (FIC index <0.5), whereas combination of certain cyclic dipeptides with ceftazidime recorded additive. The time-kill curve showed that the growth of the test bacteria was completely attenuated after 12-24 h of treatment with a 50:50 ratio of proline-based cyclic dipeptides and antibiotics. These synergistic effects have a potential role in delaying the development of resistance as the antibacterial activity is achieved with the very low concentrations of cyclic dipeptides and antibiotics. The cytotoxicity of cyclic dipeptides was tested against VERO cell line (African green monkey kidney cell line), and no cytotoxicity was recorded for cyclic dipeptides up to 100 ?g/mL. These findings suggest that combination of cyclic dipeptides and antibiotics might be a good strategy for the individualization of novel templates for the development of new antimicrobial agents or combinations of drugs for antimicrobial chemotherapy. Moreover, these combinations may lead to the development of a new and vital antimicrobial combination against the infections caused by pathogenic bacteria. The in vitro synergistic activity of cyclic dipeptides with antibiotics against medically important bacteria is reported here for the first time. PMID:24622848

Kumar, S Nishanth; Lankalapalli, Ravi S; Kumar, B S Dileep

2014-05-01

256

Amino acid composition of bulk protein and salt relationships of selected enzymes of Salinibacter ruber , an extremely halophilic bacterium  

Microsoft Academic Search

The extremely halophilic bacterium Salinibacter ruber was previously shown to have a high intracellular potassium content, comparable to that of halophilic Archaea of the family Halobacteriaceae. The amino acid composition of its bulk protein showed a high content of acidic amino acids, a low abundance of basic amino acids, a low content of hydrophobic amino acids, and a high abundance

Aharon Oren; Lili Mana

2002-01-01

257

Electrophoretic deposition of hyaluronic acid and composite films for biomedical applications  

NASA Astrophysics Data System (ADS)

Hyaluronic acid (HYH) is a natural biopolymer, which has tremendous potential for various biomedical applications. Electrophoretic deposition (EPD) methods have been developed for the fabrication of HYH films and composites. New methods for the immobilization of drugs and proteins have been utilized for the fabrication of organic composites. Electrophoretic deposition enabled the fabrication of organic-inorganic composites containing bioceramics and bioglass in the HYH matrix. It was shown that the deposition yield, microstructure, and composition of the films can be controlled. Potential applications of EPD for the surface modification of biomedical implants and fabrication of biosensors are highlighted.

Ma, R.; Li, Y.; Zhitomirsky, I.

2010-06-01

258

Synthesis and swelling behavior of Protein-g-poly Methacrylic acid/kaolin superabsorbent hydrogel composites  

NASA Astrophysics Data System (ADS)

A novel superabsorbent hydrogel composite based on Collagen have been prepared via graft copolymerization of Methacrylic acid (MAA) in the presence of kaolin powder using methylenebisacrylamide (MBA) as a crosslinking agent and ammonium persulfate (APS) as an initiator. The composite structure was confirmed using FTIR spectroscopy. A new absorption band at 1728 cm-1 in the composite spectrum confirmed kaolin-organic polymer linkage. The effect of kaolin amount and MBA concentration showed that with increasing of these parameters, the water absorbency of the superabsorbent composite was decreased. The swelling measurements of the hydrogels were conducted in aqueous salt solutions.

Sadeghi, Mohammad

2008-08-01

259

Composition of quince (Cydonia oblonga Miller) seeds: phenolics, organic acids and free amino acids.  

PubMed

Phenolic compounds, organic acids and free amino acids of quince seeds were determined by HPLC/DAD, HPLC/UV and GC/FID, respectively. Quince seeds presented a phenolic profile composed of 3-O-caffeoylquinic, 4-O-caffeoylquinic, 5-O-caffeoylquinic and 3,5-dicaffeoylquinic acids, lucenin-2, vicenin-2, stellarin-2, isoschaftoside, schaftoside, 6-C-pentosyl-8-C-glucosyl chrysoeriol and 6-C-glucosyl-8-C-pentosyl chrysoeriol. Six identified organic acids constituted the organic acid profile of quince seeds: citric, ascorbic, malic, quinic, shikimic and fumaric acids. The free amino acid profile was composed of 21 identified free amino acids and the three most abundant were glutamic and aspartic acids and asparagine. PMID:15702641

Silva, Branca M; Andrade, Paula B; Ferreres, Federico; Seabra, Rosa M; Oliveira, M Beatriz P P; Ferreira, Margarida A

2005-04-01

260

Molecular interactions between dipeptides, drugs and the human intestinal H+-oligopeptide cotransporter hPEPT1  

PubMed Central

The human intestinal proton-coupled oligopeptide transporter hPEPT1 has been implicated in the absorption of pharmacologically active compounds. We have investigated the interactions between a comprehensive selection of drugs, and wild-type and variant hPEPT1s expressed in Xenopus oocytes, using radiotracer uptake and electrophysiological methods. The ?-lactam antibiotics ampicillin, amoxicillin, cephalexin and cefadroxil, the antineoplastics ?-aminolevulinic acid (?-ALA) and bestatin, and the neuropeptide N-acetyl-Asp-Glu (NAAG), were transported, as judged by their ability to evoke inward currents. When the drugs were added in the presence of the typical substrate glycylsarcosine (Gly-Sar), the inward currents were equal or less than that induced by Gly-Sar alone. This suggests that the drugs are transported at a lower turnover rate than Gly-Sar, but may also point towards complex interactions between dipeptides, drugs and the transporter. Gly-Sar and the drugs also modified the kinetics of hPEPT1 presteady-state charge movement, by causing a reduction in maximum charge (Qmax) and a shift of the midpoint voltage (V0.5) to more negative potentials. Our results indicate that the substrate selectivity of hPEPT1 is: Gly-Sar > NAAG, ?-ALA, bestatin > cefadroxil, cephalexin > ampicillin, amoxicillin. Based on steady-state and presteady-state analysis of Gly-Sar and cefadroxil transport, we proposed an extension of the 6-state kinetic model for hPEPT1 function that globally accounts for the observed presteady-state and steady-state kinetics of neutral dipeptide and drug transport. Our model suggests that, under saturating conditions, the rate-limiting step of the hPEPT1 transport cycle is the reorientation of the empty carrier within the membrane. Variations in rates of drug cotransport are predicted to be due to differences in affinity and turnover rate. Oral availability of drugs may be reduced in the presence of physiological concentrations of dietary dipeptides in the gut, suggesting that oral delivery drugs should be taken on an empty stomach. The common hPEPT1 single-nucleotide polymorphisms Ser117Asn and Gly419Ala retained the essential kinetic and drug recognition characteristics of the wild type, suggesting that neither variant is likely to have a major impact on oral absorption of drugs.

Sala-Rabanal, Monica; Loo, Donald D F; Hirayama, Bruce A; Turk, Eric; Wright, Ernest M

2006-01-01

261

Phospholipid fatty acid composition of hepatopancreatic brush-border membrane vesicles from the prawn Penaeus japonicus.  

PubMed

Brush-border membrane vesicles (BBMV) were isolated from prawn hepatopancreas as we previously described (Muriana et al (1993) J Biochem 113, 625-629). The characterization of hepatopancreatic BBMV (hBBMV) by monitoring the activity of marker enzymes indicated a relatively pure apical membrane preparation reduced in basolateral contamination. Phospholipid composition of hBBMV was examined by the Iatroscan TLC/FID technique, whereas the fatty acid profile of phospholipids was examined by capillary gas chromatography. Phosphatidylcholine and phosphatidylethanolamine are the principal phospholipids of these membranes. The major fatty acids of phospholipids are palmitic (16:0), palmitoleic (16:1n-7), stearic (18:0), oleic (18:1n-9), eicosapentaenoic (20:5n-3) and docosapentaenoic (22:5n-3) acids. Individual phospholipids are characterized by distinct fatty acid compositions, but display a similar ratio of unsaturated-to-saturated fatty acids and a similar unsaturation index. PMID:7647111

Muriana, F J; Ruiz-Gutierrez, V; Blaya, J A; Bolufer, J

1995-01-01

262

Rapid Procedure for the Approximate Determination of the Deoxyribonucleic Acid Base Composition of Micrococci, Staphylococci, and Other Bacteria  

Microsoft Academic Search

A simple and rapid procedure for the isolation of bacterial deoxyribonucleic acid is described. The deoxyribonucleic acid preparations are pure enough to determine the base composition by ultraviolet spectroscopy. Currently the most reliable test for the sepa- ration of staphylococci and micrococci is either an analysis of their deoxyribonucleic acid (DNA) base composition or the determination of their cell wall

SOLTI A. MEYER; KARL H. SCHLEIFER

263

Phospholipid and triacylglycerol fatty acid composition of major life stages of sunn pest, Eurygaster integriceps (Heteroptera: Scutelleridae)  

Microsoft Academic Search

Phospholipid and triacylglycerol fatty acid compositions of whole animals from all life stages of Eurygaster integriceps, including eggs, nymphs, pre-diapausing adults and diapausing adults, were determined. The fatty acid composition of total lipids of their food, wheat, was also determined. The major components of the insects and their food were the expected C16 and C18 saturated and unsaturated fatty acids.

Mehmet Bashan; Halit Akbas; Kadir Yurdakoc

2002-01-01

264

Regulation of Triacylglucose Fatty Acid Composition (Uridine Diphosphate Glucose:Fatty Acid Glucosyltransferases with Overlapping Chain-Length Specificity).  

PubMed Central

UDP-glucose (UDP-Glc):fatty acid glucosyltransferases catalyze the UDP-Glc-dependent activation of fatty acids as 1-O-acyl-[beta]-glucoses. 1-O-Acyl-[beta]-glucoses act as acyl donors in the biosynthesis of 2,3,4-tri-O-acylglucoses secreted by wild tomato (Lycopersicon pennellii) glandular trichomes. The acyl composition of L. pennellii 2,3,4-tri-O-acylglucoses is dominated by branched short-chain acids (4:0 and 5:0; approximately 65%) and straight and branched medium-chain-length fatty acids (10:0 and 12:0; approximately 35%). Two operationally soluble UDP-Glc:fatty acid glucosyltransferases (I and II) were separated and partially purified from L. pennellii (LA1376) leaves by polyethylene glycol precipitation followed by DEAE-Sepharose and Cibacron Blue 3GA-agarose chromatography. Whereas both transferases possessed similar affinity for UDP-Glc, glucosyltransferase I showed higher specificity toward short-chain fatty acids (4:0) and glucosyltransferase II showed higher specificity toward medium-chain fatty acids (8:0 and 12:0). The overlapping specificity of UDP-Glc:fatty acid glucosyltransferases for 4:0 to 12:0 fatty acid chain lengths suggests that the mechanism of 6:0 to 9:0 exclusion from acyl substituents of 2,3,4-tri-O-acylglucoses is unlikely to be controlled at the level of fatty acid activation. UDP-Glc:fatty acid glucosyltransferases are also present in cultivated tomato (Lycopersicon esculentum), and activities toward 4:0, 8:0, and 12:0 fatty acids do not appear to be primarily epidermal when assayed in interspecific periclinal chimeras.

Kuai, J. P.; Ghangas, G. S.; Steffens, J. C.

1997-01-01

265

Effect of dietary conjugated linoleic acid in combination with monounsaturated fatty acids on the meat composition and quality traits of dry-cured loin  

Microsoft Academic Search

Three levels (0%, 1% and 2%) of an enriched conjugated linoleic acid oil (CLA) were combined with two levels of monounsaturated fatty acids (MUFA) (low ?19% average and high ?39% average) for pig feeding. Composition, weight losses, lipid oxidation (thiobarbituric acid test, TBARs), change in the fatty acid content of the lipid fractions and sensory analysis of dry-cured loin as

Diana Martin; Teresa Antequera; Elena Muriel; Trinidad Perez-Palacios; Jorge Ruiz

2008-01-01

266

Fatty Acid Composition of Myelin Proteolipid Protein During Vertebrate Evolution  

Microsoft Academic Search

The hydrophobic myelin proteolipid protein (PLP) contains covalently bound long-chain fatty acids which are attached to intracellular cysteine residues via thioester linkages. To gain insight into the role of acylation in the structure and function of myelin PLP, the amount and pattern of acyl groups attached to the protein during vertebrate evolution was determined. PLP isolated from brain myelin of

Oscar A. Bizzozero; Marjorie B. Lees

1999-01-01

267

A Novel ?-Peptidyl Aminopeptidase (BapA) from Strain 3-2W4 Cleaves Peptide Bonds of Synthetic ?-Tri- and ?-Dipeptides  

PubMed Central

A novel bacterial strain that was capable of growing on the ?-tripeptide H-?hVal-?hAla-?hLeu-OH as the sole carbon and nitrogen source was isolated from an enrichment culture. On the basis of physiological characterization, partial 16S rRNA sequencing, and fatty acid analysis, strain 3-2W4 was identified as a member of the family Sphingomonadaceae. Growth on the ?-tripeptide and the ?-dipeptide H-?hAla-?hLeu-OH was observed, and emerging metabolites were characterized. Small amounts of a persisting metabolite, the N-acetylated ?-dipeptide, were identified in both media. According to dissolved organic carbon measurements, 74 to 80% of the available carbon was dissimilated. The ?-peptide-degrading enzyme was purified from the crude cell extract of cells from strain 3-2W4 grown on complex medium. The enzyme was composed of two subunits, and the N-terminal sequences of both were determined. With this information, it was possible to identify the complete nucleotide sequence and to deduce the primary structure of the gene bapA. The gene encoded a ?-peptidyl aminopeptidase (BapA) of 402 amino acids that was synthesized as preprotein with a signal sequence of 29 amino acids. The enzyme was cleaved into two subunits (residues 30 to 278 and 279 to 402). It belonged to the N-terminal nucleophile (Ntn) hydrolase superfamily.

Geueke, Birgit; Namoto, Kenji; Seebach, Dieter; Kohler, Hans-Peter E.

2005-01-01

268

Phenolic acid composition and antioxidant capacity of acid and alkali hydrolysed wheat bran fractions  

Microsoft Academic Search

Phenolic acid concentrations, profiles and antioxidant capacity of acid and alkali hydrolysates from the bran of six wheat cultivars representing six Canadian market classes were determined. Aqueous ethanol was used to extract the free phenolics (FP) and diethyl ether to extract the insoluble bound phenolics released after acid and alkaline hydrolysis of the bran. Folin–Ciocalteu (FC) reagent was used to

B. Verma; P. Hucl; R. N. Chibbar

2009-01-01

269

Genome-wide association study for fatty acid composition in Japanese Black cattle.  

PubMed

Fatty acid composition is one of the important traits in beef. The aim of this study was to identify candidate genomic regions for fatty acid composition by genome-wide association study with 50?K single nucleotide polymorphism (SNP) array in Japanese Black cattle. A total of 461 individuals and 40?657 SNPs were used in this study. We applied genome-wide rapid association using mixed model and regression (GRAMMAR) and genomic control approaches to estimate the associations between genotypes and fatty acid composition. In addition, two SNPs in fatty acid synthase (FASN) (T1952A) and stearoyl-CoA desaturase (SCD) (V293A) genes were also genotyped. Association analysis revealed that 30 significant SNPs for several fatty acids (C14:0, C14:1, C16:1 and C18:1) were located in the BTA19?FASN gene located within this region but the FASN mutation had no significant effect on any traits. We also detected one significant SNP for C18:1 on BTA23 and two SNPs for C16:0 on BTA25. The region around 17?Mb on BTA26 harbored two significant SNPs for C14:1 and SNP in SCD in this region showed the strongest association with C14:1. This study demonstrated novel candidate regions in BTA19, 23 and 25 for fatty acid composition. PMID:23607548

Ishii, Atsushi; Yamaji, Keita; Uemoto, Yoshinobu; Sasago, Nanae; Kobayashi, Eiji; Kobayashi, Naohiko; Matsuhashi, Tamako; Maruyama, Shin; Matsumoto, Hirokazu; Sasazaki, Shinji; Mannen, Hideyuki

2013-10-01

270

Radiation Resistance and Deoxyribonucleic Acid Base Composition of Micrococcus radiodurans  

Microsoft Academic Search

Micrococcus radiodurans is a red-pigmented, non-sporing bacterium which is extremely resistant to both ionizing1 and ultra-violet radiations2. The mechanisms of resistance are not known. In 1962 Kaplan and Zavarine3 examined the relationship between the base composition of DNA in eight species of bacteria and their resistance to X-radiation. On plotting the X-ray dose which reduced the surviving bacteria to 10

B. E. B. Moseley; ARNOLD H. SCHEIN

1964-01-01

271

Composition of mares' colostrum and milk. Protein content, amino acid composition and contents of macro and micro-elements  

Microsoft Academic Search

Changes in the protein content, protein fractions and amino acid composition of mare's colostrum and milk, and the biological value of milk protein during the first 45 days of lactation were studied. Milk samples (averaging 300–800 cm3) from 29 lactating mares were collected daily at the beginning of lactation and weekly from the 5th to 45th days post-partum. Colostrum samples

Zs. Csapó-Kiss; J. Stefler; T. G. Martin; S. Makray; J. Csapó

1995-01-01

272

Chiral separations using a polypeptide and polymeric dipeptide surfactant polyelectrolyte multilayer coating in open-tubular capillary electrochromatography.  

PubMed

A polyelectrolyte multilayer (PEM) coating consisting of the polypeptide, poly(l-lysine) hydrobromide, poly(l-lysine) and the polymeric dipeptide surfactant, poly(sodium undecanoyl-l-leucyl-alaninate), poly(l-SULA), is investigated as a new medium for the separation of chiral analytes in open-tubular capillary electrochromatography (OT-CEC). In this approach, a stable PEM is constructed in situ by alternative rinses of the cationic polymer poly(l-lysine) and the anionic polymer poly(l-SULA). In previous studies, the PEM coating has been constructed by use of the cationic polyelectrolyte poly (diallydimethylammonium chloride), PDADMAC. In this study, we investigate the use of a biopolymer as the cationic polyelectrolyte. The results reported here indicate an increase in selectivity and resolution when poly(l-lysine) is used as the cationic polymer in place of PDADMAC. To evaluate the chromatographic performance of the PEM coating as a chiral stationary phase, the separation of the beta-blockers, labetalol and sotalol, and the binaphthyl derivatives, 1,1'-bi-2-naphthyl-2,2'-dihydrogen phosphate, 1,1'-bi-2-naphthol, and 1,1-binaphthyl-2,2'-diamine, are investigated. In addition, the effect of varying the amino acid order of the polymeric dipeptide surfactant on resolution is investigated. The number of bilayers also significantly influences the separation efficiency and resolution of enantiomers. The run-to-run and capillary-to-capillary reproducibilities are evaluated by calculating the relative standard deviations (RSDs) of the electroosmotic flow. These RSD values were found to be less than 1%. The coating is also stable and allows more than 290 runs to be performed in the same capillary. In addition, coupling of this chiral OT-CEC column with mass spectrometry is investigated. PMID:15538792

Kamande, Mary W; Zhu, Xiaofeng; Kapnissi-Christodoulou, Constantina; Warner, Isiah M

2004-11-15

273

MACAIBA PALM: FATTY AND AMINO ACIDS COMPOSITION OF FRUITS  

Microsoft Academic Search

The lipid content of dried pulp and kernels of Acrocomia intumescens palm fruits grown in the Northeast region of Brazil was determined to be about 34.6 and 49.2.6%, respectively. The hexane extracted oils from these parts showed refractive indices - 1.4427 and 1.4310, specific gravity - 0.9012 and 0.9213, peroxide - 2.96 and 1.37, acid - 1.5 and 2.1, iodine

P. S. Bora

2004-01-01

274

Hormone-sensitive lipase deficiency disturbs the fatty acid composition of mouse testis.  

PubMed

Hormone-sensitive lipase (HSL) is a key enzyme in the mobilization of fatty acids from intracellular stores. In mice, HSL deficiency results in male sterility caused by a major defect in spermatogenesis. The testes contain high concentrations of PUFA and specific PUFA are essential for spermatogenesis. We investigated the fatty acid composition and the mRNA levels of key enzymes involved in fatty acid metabolism in testis of HSL-knockout mice. HSL deficiency altered fatty acid composition in the testis but not in plasma. The most important changes were decreases in the essential n-6 PUFA LNA and the n-3 PUFA ALA, and an increase in the corresponding synthesis intermediates C22:4n-6 and C22:5n-3 without changes in DPAn-6 or DHA acids. Mead acid, which has been associated with an essential fatty acid deficit leading to male infertility, was increased in the testis from HSL-knockout mice. Moreover, the expression of SCD-1, FADS1, and FADS2 was increased while expression of ELOVL2, an essential enzyme for the formation of very-long PUFA in testis, was decreased. Given the indispensability of these fatty acids for spermatogenesis, the changes in fatty acid metabolism observed in testes from HSL-knockout male mice may underlie the infertility of these animals. PMID:23369366

Casado, M E; Pastor, O; Mariscal, P; Canfrán-Duque, A; Martínez-Botas, J; Kraemer, F B; Lasunción, M A; Martín-Hidalgo, A; Busto, R

2013-03-01

275

Fatty acid composition of adipose tissue triglycerides after weight loss and weight maintenance: the DIOGENES study.  

PubMed

Fatty acid composition of adipose tissue changes with weight loss. Palmitoleic acid as a possible marker of endogenous lipogenesis or its functions as a lipokine are under debate. Objective was to assess the predictive role of adipose triglycerides fatty acids in weight maintenance in participants of the DIOGENES dietary intervention study. After an 8-week low calorie diet (LCD) subjects with > 8 % weight loss were randomized to 5 ad libitum weight maintenance diets for 6 months: low protein (P)/low glycemic index (GI) (LP/LGI), low P/high GI (LP/HGI), high P/low GI (HP/LGI), high P/high GI (HP/HGI), and a control diet. Fatty acid composition in adipose tissue triglycerides was determined by gas chromatography in 195 subjects before the LCD (baseline), after LCD and weight maintenance. Weight change after the maintenance phase was positively correlated with baseline adipose palmitoleic (16:1n-7), myristoleic (14:1n-5) and trans-palmitoleic acid (16:1n-7t). Negative correlation was found with baseline oleic acid (18:1n-9). Lower baseline monounsaturated fatty acids (14:1n-5, 16:1n-7 and trans 16:1n-7) in adipose tissue triglycerides predict better weight maintenance. Lower oleic acid predicts lower weight decrease. These findings suggest a specific role of monounsaturated fatty acids in weight management and as weight change predictors. PMID:23098653

Kunešová, M; Hlavatý, P; Tvrzická, E; Sta?ková, B; Kalousková, P; Viguerie, N; Larsen, T M; van Baak, M A; Jebb, S A; Martinez, J A; Pfeiffer, A F H; Kafatos, A; Handjieva-Darlenska, T; Hill, M; Langin, D; Zák, A; Astrup, A; Saris, W H M

2012-01-01

276

Fatty Acid Composition of Adipose Tissue Triglycerides After Weight Loss and Weight Maintenance: the DIOGENES Study  

PubMed Central

Summary Fatty acid composition of adipose tissue changes with weight loss. Palmitoleic acid as a possible marker of endogenous lipogenesis or its functions as a lipokine are under debate. Objective was to assess the predictive role of adipose triglycerides fatty acids in weight maintenance in participants of the DIOGENES dietary intervention study. After an 8-week low calorie diet (LCD) subjects with > 8 % weight loss were randomized to 5 ad libitum weight maintenance diets for 6 months: low protein (P)/low glycemic index (GI) (LP/LGI), low P/high GI (LP/HGI), high P/low GI (HP/LGI), high P/high GI (HP/HGI), and a control diet. Fatty acid composition in adipose tissue triglycerides was determined by gas chromatography in 195 subjects before the LCD (baseline), after LCD and weight maintenance. Weight change after the maintenance phase was positively correlated with baseline adipose palmitoleic (16:1n-7), myristoleic (14:1n-5) and trans-palmitoleic acid (16:1n-7t). Negative correlation was found with baseline oleic acid (18:1n-9). Lower baseline monounsaturated fatty acids (14:1n-5, 16:1n-7 and trans 16:1n-7) in adipose tissue triglycerides predict better weight maintenance. Lower oleic acid predicts lower weight decrease. These findings suggest a specific role of monounsaturated fatty acids in weight management and as weight change predictors.

KUNESOVA, M.; HLAVATY, P.; TVRZICKA, E.; STANKOVA, B.; KALOUSKOVA, P.; VIGUERIE, N.; LARSEN, T. M.; VAN BAAK, M. A.; JEBB, S. A.; MARTINEZ, J. A.; PFEIFFER, A. F. H.; KAFATOS, A.; HANDJIEVA-DARLENSKA, T.; HILL, M.; LANGIN, D.; ZAK, A.; ASTRUP, A.; SARIS, W. H. M.

2013-01-01

277

Phenolic acid induced growth of gold nanoshells precursor composites and their application in antioxidant capacity assay.  

PubMed

In the present work, the gold nanoshells (GNSs) precursor composites were preadsorbed onto the surface of ITO substrates. With the treatment of modified electrodes immersed in the gold nanoparticles (GNPs) growth solution containing different phenolic acids, the GNSs precursor composites were enlarged to varying degrees. Phenolic acids with one or more phenolic hydroxyl groups served as reductants for the growth of GNPs. The enlargement conditions varied with the different reducing capacity of phenolic acids, exhibiting specific morphologies differ from the complete GNSs. Consequently, the UV-vis-NIR spectra and cyclic voltammetry curves for the phenolic acid-treated ITO electrode were gradually changed. Results showed that the higher reducing capacity for phenolic acid to reduce AuCl(4)(-) to Au(0) resulted in the intensified localized surface plasmon resonance features and reduced cathodic currents. The spectral wavelength peaks red shifted hundreds of nanometers across the visible region. Moreover, the antioxidant capacity of phenolic acids correlates well with their reducing activity, both of which reflect their tendency to donate electrons. Thus, the optical and electrochemical results could be used to evaluate the antioxidant capacity of phenolic acids by utilizing GNSs precursor composites as nanoprobes. The method is simple, rapid and could be used in visual analysis to a certain extent. PMID:20863682

Ma, Xiaoyuan; Qian, Weiping

2010-11-15

278

Solid Sulfonic Acid Catalysts Based on Porous Carbons and Carbon-Silica Composites  

NASA Astrophysics Data System (ADS)

Mesoporous carbons prepared using a templating method under different carbonization temperatures are sulfonated with concentrated H2SO4. Without the moving of silica template carbon-silica composites were prepared, which can maintain the pore structure well during sulfonation reaction process. The resultant samples are characterized using nitrogen adsorption, transmission electron microscope, field-emission scanning electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy, and elemental analysis techniques. The catalytic performances of the sulfonated carbons and composites are evaluated by esterification reaction of methanol with acetic acid. The results show that a low-temperature carbonization process is favorable for improving the reaction conversion of acetic acid. In addition, the sulfonated carbon-silica composites show a higher acetic acid conversion than the sulfonated mesoporous carbons.

Tian, Xiao Ning; Luo, Lijuan; Jiang, Zhongqing; Zhao, X. S.

279

Method for Detection of Thiol-containing Amino Acids Using Gold-Polystyrene Composites  

PubMed Central

This paper reports the preparation of PS-PEI-Au composite colloids via the utilization of a facile method involving poly(ethylenimine) (PEI). The PEI used in the reaction scheme served the role of a linker between Au and PS and additionally as a reducing agent in the conversion of Au ions to Au NPs. The PS-PEI-Au colloids thus prepared were characterized by scanning electron microscopy, UV-Vis and IR spectroscopy and cyclic voltammetry. The PS-PEI-Au composites were further used for the detection of the thiol-containing amino acids, cysteine and homocysteine, via Attenuated Total Reflection (ATR) spectroscopy. Experimental results revealed interfacial binding of the amino acids to the composites, and correlated with successive additions of the respective amino acids.

Murray, Davoy

2009-01-01

280

Dietary Supplementation with Docosahexaenoic Acid, but Not Eicosapentanoic Acid, Dramatically Alters Cardiac Mitochondrial Phospholipid Fatty Acid Composition and Prevents Permeability Transition  

PubMed Central

Treatment with the ?-3 polyunsaturated fatty acids (PUFAs) docosahexanoic acid (DHA) and eicosapentanoic acid (EPA) exerts cardioprotective effects, and suppresses Ca2+-induced opening of the mitochondrial permeability transition pore (MPTP). These effects are associated with increased DHA and EPA, and lower arachidonic acid (ARA) in cardiac phospholipids. While clinical studies suggest the triglyceride lowering effects of DHA and EPA are equivalent, little is known about the independent effects of DHA and EPA on mitochondria function. We compared the effects of dietary supplementation with the ?-3 PUFAs DHA and EPA on cardiac mitochondrial phospholipid fatty acid composition and Ca2+-induced MPTP opening. Rats were fed a standard lab diet with either normal low levels of ?-3 PUFA, or DHA or EPA at 2.5% of energy intake for 8 weeks, and cardiac mitochondria were isolated and analyzed for Ca2+-induced MPTP opening and phospholipid fatty acyl composition. DHA supplementation increased both DHA and EPA and decreased ARA in mitochondrial phospholipid, and significantly delayed MPTP opening as assessed by increased Ca2+ retention capacity and decreased Ca2+-induced mitochondria swelling. EPA supplementation increased EPA in mitochondrial phospholipids, but did not affect DHA, only modestly lowered ARA, and did not affect MPTP opening. In summary, dietary supplementation with DHA but not EPA, profoundly altered mitochondrial phospholipid fatty acid composition and delayed Ca2+-induced MPTP opening.

Khairallah, Ramzi J.; Sparagna, Genevieve C.; Khanna, Nishanth; O'Shea, Karen M.; Hecker, Peter A.; Kristian, Tibor; Fiskum, Gary; Rosiers, Christine Des; Polster, Brian M.; Stanley, William C.

2010-01-01

281

Comparison of the Morphology and Deoxyribonucleic Acid Composition of 27 Strains of Nitrifying Bacteria1  

PubMed Central

The gross morphology, fine structure, and per cent guanine plus cytosine (GC) composition of deoxyribonucleic acid of 27 strains of nitrifying bacteria were compared. Based on morphological differences, the ammonia-oxidizing bacteria were separated into four genera. Nitrosomonas species and Nitrosocystis species formed one homogenous group, and Nitrosolobus species and Nitrosospira species formed a second homogenous group in respect to their deoxyribonucleic acid GC compositions. Similarly, the nitrite-oxidizing bacteria were separated into three genera based on their morphology. The members of two of these nitrite-oxidizing genera, Nitrobacter and Nitrococcus, had similar GC compositions, but Nitrospina gracilis had a significantly lower GC composition than the members of the other two genera. Images

Watson, Stanley W.; Mandel, Manley

1971-01-01

282

The effect of diet on the fatty acid compositions of serum, brain, brain mitochondria and myelin in the rat  

PubMed Central

1. Three groups of female rats (8–12 weeks old) were maintained respectively on a linoleic acid-rich diet, a linoleic acid-poor predominantly saturated-fatty acid diet and a normal diet. Changes in the fatty acid compositions of serum, brain, brain mitochondria-rich fraction and myelin were observed. 2. Of the serum fatty acids, linoleic acid showed the greatest change in the percentage of the total acids in response to diet; the change in the proportion of oleic acid was considerable. The percentages of arachidonic acid in serum fatty acids in the groups on the linoleic acid-rich and linoleic acid-poor diets were similar, but higher than those in the normal group. 3. Changes in the proportions of linoleic acid, arachidonic acid and docosahexaenoic acid occurred in brain fatty acids that to some extent paralleled those occurring in the serum. Changes in the proportions of most other acids in the serum fatty acids were not accompanied by corresponding changes in the brain fatty acids. 4. The percentage fatty acid compositions of a mitochondria-rich fraction and myelin are given, and changes in the relative proportions of linoleic acid, arachidonic acid and possibly some docosapolyenoic acids were demonstrated to occur as a result of diet. 5. The results are discussed in relation to the possible aetiology of multiple sclerosis.

Rathbone, L.

1965-01-01

283

Prebiotic syntheses of vitamin coenzymes: II. Pantoic acid, pantothenic acid, and the composition of coenzyme A  

NASA Technical Reports Server (NTRS)

Pantoic acid can by synthesized in good prebiotic yield from isobutyraldehyde or alpha-ketoisovaleric acid + H2CO + HCN. Isobutyraldehyde is the Strecker precursor to valine and alpha-ketoisovaleric acid is the valine transamination product. Mg2+ and Ca2+ as well as several transition metals are catalysts for the alpha-ketoisovaleric acid reaction. Pantothenic acid is produced from pantoyl lactone (easily formed from pantoic acid) and the relatively high concentrations of beta-alanine that would be formed on drying prebiotic amino acid mixtures. There is no selectivity for this reaction over glycine, alanine, or gamma-amino butyric acid. The components of coenzyme A are discussed in terms of ease of prebiotic formation and stability and are shown to be plausible choices, but many other compounds are possible. The gamma-OH of pantoic acid needs to be capped to prevent decomposition of pantothenic acid. These results suggest that coenzyme A function was important in the earliest metabolic pathways and that the coenzyme A precursor contained most of the components of the present coenzyme.

Miller, S. L.; Schlesinger, G.

1993-01-01

284

Lipid and fatty acid composition and energy partitioning during embryo development in the shrimp Macrobrachium borellii  

Microsoft Academic Search

Energy partitioning, composition of lipids and fatty acids, and their utilization by embryos were determined in the lecithotrophic\\u000a shrimp Macrobrachium borellii during seven development stages. The biochemical composition at stage I is represented by lipids, proteins, and carbohydrates,\\u000a with 29.3, 28.7, and 0.2% dry weight, respectively. The former two were identified as the major energy-providing components,\\u000a contributing 131 and 60

Horacio Heras; M. R. Gonzalez-Baró; Ricardo J. Pollero

2000-01-01

285

Molecular relaxations in the composites of liquid crystalline cellulose derivatives with poly(acrylic acid)  

Microsoft Academic Search

The molecular relaxation phenomena of the specific polymer composites obtained by photopolymerisation of the oriented lyotropic\\u000a liquid-crystalline systems composed of cellulose derivatives dissolved in photopolymerisable acrylic acid are studied. We\\u000a have investigated the composites based on two cellulose derivatives, which differ by the length of their side-chains and consequently\\u000a by their physical properties.\\u000a \\u000a In this work, the molecular relaxations of

Lidia Okrasa; G. Boiteux; J. Ulanski; G. Seytre

2001-01-01

286

Seasonal distribution and fatty acid composition of littoral microalgae in the Yenisei River  

Microsoft Academic Search

We studied fatty acid (FA) composition of littoral microalgae in the fast-flowing oligotrophic river, the Yenisei, Siberia,\\u000a monthly for 3 years. Seasonal dynamics of species composition had similar patterns in all the studied years. In springs, a\\u000a pronounced dominance of filamentous green algae occurred, in summer and autumn diatoms were abundant, and in late autumn and\\u000a winter epilithic biofilms consisted primarily

Nadezhda N. Sushchik; Michail I. Gladyshev; Elena A. Ivanova; Elena S. Kravchuk

2010-01-01

287

Biocompatibility of Electrospun Halloysite Nanotube-Doped Poly(Lactic-co-Glycolic Acid) Composite Nanofibers  

Microsoft Academic Search

Organic\\/inorganic hybrid nanofiber systems have generated great interest in the area of tissue engineering and drug delivery. In this study, halloysite nanotube (HNT)-doped poly(lactic-co-glycolic acid) (PLGA) composite nanofibers were fabricated via electrospinning and the influence of the incorporation of HNTs within PLGA nanofibers on their in vitro biocompatibility was investigated. The morphology, mechanical and thermal properties of the composite nanofibers

Ruiling Qi; Xueyan Cao; Mingwu Shen; Rui Guo; Jianyong Yu; Xiangyang Shi

2012-01-01

288

Variability in the fatty acid composition of rapeseed oil: Classical breeding and biotechnology  

Microsoft Academic Search

This paper analyzes the problems of and achievements in rapeseed (Brassica napus L. var. oleifera) breeding directed at the change of the fatty acid composition in seed oil using the approaches of traditional selection\\u000a and genetic engineering. It is noted that the combination of biotechnological developments and methods of classical breeding\\u000a is optimal for the further improvement of the composition

L. O. Sakhno

2010-01-01

289

A novel basalt fiber-reinforced polylactic acid composite for hard tissue repair  

Microsoft Academic Search

A basalt fiber (BF) was, for the first time, introduced into a poly(l-lactic acid) (PLLA) matrix as innovative reinforcement to fabricate composite materials for hard tissue repair. Firstly, BF\\/PLLA composites and pure PLLA were produced by the methods of solution blending and freeze drying. The results showed that basalt fibers can be uniformly dispersed in the PLLA matrix and significantly

Xi Chen; Yan Li; Ning Gu

2010-01-01

290

Mutants of Arabidopsis with alterations in seed lipid fatty acid composition  

Microsoft Academic Search

A diverse collection of mutants of Arabidopsis with altered seed lipid compositions was isolated by determining the fatty acid composition of samples of seed from 3,000 mutagenized lines. A series of mutations was identified that caused deficiencies in the elongation of 18:1 to 20:1, desaturation of 18:1 to 18:2, and desaturation of 18:2 to 18:3. In each of these cases

B. Lemieux; M. Miquel; C. Somerville; J. Browse

1990-01-01

291

Preparation of mesoporous polyoxometalate–tantalum pentoxide composite catalyst for efficient esterification of fatty acid  

Microsoft Academic Search

Mesoporous polyoxometalate–tantalum pentoxide composite catalyst, H3PW12O40\\/Ta2O5, was prepared by a one-step sol–gel-hydrothermal method in the presence of triblock copolymer surfactant. Structure, morphology and surface textural property of the composite were characterized. As-prepared H3PW12O40\\/Ta2O5 was applied as a solid acid catalyst for esterification reaction of lauric acid with ethanol, an important pretreatment step in the production of biodiesel from renewable feedstocks.

Leilei Xu; Xia Yang; Xiaodan Yu; Yihang Guo; Maynurkader

2008-01-01

292

Dependence of fatty-acid composition of edible oils on their enrichment in olive phenols.  

PubMed

Olive phenol extracts from waste from olive-oil production (alperujo) have been obtained by microwave-assisted extraction and used for edible oil enrichment. The extracts as such or after extractant removal were used to enrich edible oils of different fatty acid composition by liquid-liquid or solid-liquid extraction, respectively. The distribution ratios of the phenols in the different oils [olive-orujo (the waste of milled olives from which low-quality oil is obtained), sunflower, high oleic-acid content sunflower, coconut, and linseed] showed a given order as a function of phenol polarity and molecular weight, with higher distribution factors for more polar and lower molecular-weight phenols. Concerning oil composition, those oils with higher concentration of polyunsaturated fatty acids yielded higher phenol distribution factors; oils with higher concentrations of saturated fatty acids yielded lower distribution factors. PMID:19253972

Girón, María Victoria; Ruiz-Jiménez, José; Luque de Castro, María Dolores

2009-04-01

293

Correlations between nucleotide frequencies and amino acid composition in 115 bacterial species.  

PubMed

We studied the correlations between amino acid composition and mononucleotide and dinucleotide frequencies in 115 bacterial genomes of varying G+C content. Observed amino acid frequencies were compared with those expected from the actual mononucleotide and dinucleotide frequencies. Both mononucleotide and dinucleotide frequencies correlate well with the amino acid frequency, with dinucleotide frequencies doing so better. Despite the strong correlations, some of the observed amino acid frequencies, in particular for Arg, Val, Asp, Glu, Ser, and Cys, were consistently different from predicted values in all genomes. We suggest that this variation from predicted values is a consequence of selection pressure at the level of amino acids, while the close correspondence to the predictions in residues such as Thr, Phe, Lys, and Asn arises only from mutation and selection pressure at the level of the nucleic acid sequences. PMID:14985126

Bharanidharan, D; Bhargavi, G Ramya; Uthanumallian, Kavitha; Gautham, N

2004-03-19

294

[Pancreatic exocrine secretion to the introduction into the blood of amino acid mixtures of varying composition].  

PubMed

Tests conducted on dogs with a fistula of the pancreatic duct evidenced that various amino acids mixtures containing all the essential amino acids and differing mainly in the replaceable nitrogen dissimilarly act on the external secretion of the pancreas after their introduction into the blood. The most intensive secretion produces a mixture in which the replaceable nitrogen is represented by glycine alone. The mixture, one of its constituent is one of the dicarboxylic acids (glutamic) very poorly stimulates this function. At the same time, the action of all the studied amino acids mixtures is less pronounced than is the effect of the caseine hydrolysate. The commercial agent aminofusin L-600, containing all the essential amino acids with addition of polyols (xylitol and sorbitol) with no dicarboxylic amino acids in its composition, produces an intensive pancreatic secretion close to that caused by the caseine hydrolysate. PMID:28607

Sysoev, Iu A; Kremer, Iu N; Shlygin, G K

1978-01-01

295

Dynamics of fatty-acid composition of neutral acylglycerols in maturing euonymus fruits.  

PubMed

The dynamics of the fatty-acid (FA) composition of neutral acylglycerols (NAGs) composed of 1,2,3-triacyl-sn-glycerols (TAGs) and 3-acetyl-1,2-diacyl-sn-glycerols (acDAGs) was determined in the fruit seeds and arils of three Euonymus L. species at three stages of their maturity. The NAG composition comprised 29 FAs, linoleic, oleic, palmitic, and ?-linolenic acids being predominant. Noticeable amounts of other FAs, such as lauric, myristic, hexadec-9-enoic, stearic, (Z)-vaccenic, and arachidic acid, etc., could also be present. In the course of maturation, the qualitative composition of major FAs remained nearly unchanged, while the unsaturation index of FAs in seeds and in TAGs, as well as, but to a lesser extent, in arils and in acDAGs, respectively, always decreased. This decline was brought about by a sharp fall of the ?-linolenate level, a decrease of the linoleate content, and a corresponding rise in the oleate content. It is suggested that, in both seeds and arils, both classes of NAGs were formed at the expense of the same FA pool; the quantitative composition of this pool was characteristic of a given fruit part and strongly changed during maturation. The accumulation of TAGs in E. europaeus fruits was accompanied by a conversion of hexadec-9-enoic acid into (Z)-vaccenic acid via the C2 -elongation reaction. PMID:24706628

Sidorov, Roman A; Zhukov, Anatoly V; Pchelkin, Vasily P; Vereshchagin, Andrei G; Tsydendambaev, Vladimir D

2014-04-01

296

Copper toxicity towards Saccharomyces cerevisiae: dependence on plasma membrane fatty acid composition.  

PubMed Central

One major mechanism of copper toxicity towards microorganisms is disruption of plasma membrane integrity. In this study, the influence of plasma membrane fatty acid composition on the susceptibility of Saccharomyces cerevisiae to Cu2+ toxicity was investigated. Microbial fatty acid composition is highly variable, depending on both intrinsic and environmental factors. Manipulation was achieved in this study by growth in fatty acid-supplemented medium. Whereas cells grown under standard conditions contained only saturated and monounsaturated fatty acids, considerable incorporation of the diunsaturated fatty acid linoleate (18:2) (to more than 65% of the total fatty acids) was observed in both whole-cell homogenates and plasma membrane-enriched fractions from cells grown in linoleate-supplemented medium. Linoleate enrichment had no discernible effect on the growth of S. cerevisiae. However, linoleate-enriched cells were markedly more susceptible to copper-induced plasma membrane permeabilization. Thus, after addition of Cu(NO3)2, rates of cellular K+ release (loss of membrane integrity) were at least twofold higher from linoleate-supplemented cells than from unsupplemented cells; this difference increased with reductions in the Cu2+ concentration supplied. Levels of cellular Cu accumulation were also higher in linoleate-supplemented cells. These results were correlated with a very marked dependence of whole-cell Cu2+ toxicity on cellular fatty acid unsaturation. For example, within 10 min of exposure to 5 microM Cu2+, only 3% of linoleate-enriched cells remained viable (capable of colony formation). In contrast, 100% viability was maintained in cells previously grown in the absence of a fatty acid supplement. Cells displaying intermediate levels of linoleate incorporation showed intermediate Cu2+ sensitivity, while cells enriched with the triunsaturated fatty acid linolenate (18:3) were most sensitive to Cu2+. These results demonstrate for the first time that changes in cellular and plasma membrane fatty acid compositions can dramatically alter microbial sensitivity to copper.

Avery, S V; Howlett, N G; Radice, S

1996-01-01

297

Amino acid composition, including key derivatives of eccrine sweat: potential biomarkers of certain atopic skin conditions.  

PubMed

The free amino acid (AA) composition of eccrine sweat is different from other biological fluids, for reasons which are not properly understood. We undertook the detailed analysis of the AA composition of freshly isolated pure human eccrine sweat, including some of the key derivatives of AA metabolism, to better understand the key biological mechanisms governing its composition. Eccrine sweat was collected from the axillae of 12 healthy subjects immediately upon formation. Free AA analysis was performed using an automatic AA analyser after ninhydrin derivatization. Pyrrolidine-5-carboxylic acid (PCA) and urocanic acid (UCA) levels were determined using GC/MS. The free AA composition of sweat was dominated by the presence of serine accounting for just over one-fifth of the total free AA composition. Glycine was the next most abundant followed by PCA, alanine, citrulline and threonine, respectively. The data obtained indicate that the AA content of sweat bears a remarkable similarity to the AA composition of the epidermal protein profilaggrin. This protein is the key source of free AAs and their derivatives that form a major part of the natural moisturizing factor (NMF) within the stratum corneum (SC) and plays a major role in maintaining the barrier integrity of human skin. As perturbations in the production of NMF can lead to abnormal barrier function and can arise as a consequence of filaggrin genotype, we propose the quantification of AAs in sweat may serve as a non-invasive diagnostic biomarker for certain atopic skin conditions, that is, atopic dermatitis (AD). PMID:23075272

Mark, Harker; Harding, Clive R

2013-04-01

298

Enzymatically cross-linked alginic-hyaluronic acid composite hydrogels as cell delivery vehicles.  

PubMed

An injectable composite gel was developed from alginic and hyaluronic acid. The enzymatically cross-linked injectable gels were prepared via the oxidative coupling of tyramine modified sodium algiante and sodium hyaluronate in the presence of horse radish peroxidase (HRP) and hydrogen peroxide (H2O2). The composite gels were prepared by mixing equal parts of the two tyraminated polymer solutions in 10U HRP and treating with 1.0% H2O2. The properties of the alginate gels were significantly affected by the addition of hyaluronic acid. The percentage water absorption and storage modulus of the composite gels were found to be lower than the alginate gels. The alginate and composite gels showed lower protein release compared to hyaluronate gels in the absence of hyaluronidase. Even hyaluronate gels showed only approximately 10% protein release after 14 days incubation in phosphate buffer solution. ATDC-5 cells encapsulated in the injectable gels showed high cell viability. The composite gels showed the presence of enlarged spherical cells with significantly higher metabolic activity compared to cells in hyaluronic and alginic acid gels. The results suggest the potential of the composite approach to develop covalently cross-linked hydrogels with tuneable physical, mechanical, and biological properties. PMID:23357799

Ganesh, Nitya; Hanna, Craig; Nair, Shantikumar V; Nair, Lakshmi S

2013-04-01

299

Enzymatically Cross-linked Alginic-Hyaluronic acid Composite Hydrogels As Cell Delivery Vehicles  

PubMed Central

An injectable composite gel was developed from alginic and hyaluronic acid. The ezymatically cross-linked injectable gels were prepared via the oxidative coupling of tyramine modified sodium algiante and sodium hyaluronate in the presence of horse radish peroxidase (HRP) and hydrogen peroxide (H2O2). The composite gels were prepared by mixing equal parts of the two tryaminated polymer solutions in 10U HRP and treating with 1.0% H2O2. The properties of the alginate gels were significanly affected by the addition of hyaluronic acid. The percentage water absorption and storage modulus of the composite gels were found to be lower than the alginate gels. The alginate and composite gels showed lower protein release compared to hyaluronate gels in the absence of hyaluronidase. Even hyaluronate gels showed only approximately 10% protein release after 14 days incubation in phosphate buffer solution. ATDC-5 cells encapsulated in the injectable gels showed high cell viability. The composite gels showed the presence of enlarged spherical cells with significantly higher metabolic activity compared to cells in hyaluronic and alginic acid gels. The results suggest the potential of the composite approach to develop covalently cross-linked hydrogels with tuneable physical, mechanical, and biological properties.

Ganesh, Nitya; Hanna, Craig; Nair, Shantikumar V.; Nair, Lakshmi S.

2013-01-01

300

Lipid content and fatty acid composition of 11 species of Queensland (Australia) fish.  

PubMed

The fatty acid composition of 11 species of fish caught of the northeast coast of Australia was determined. No fatty acid profiles have been previously published for fish from this area nor for nine of these species. Although the percentage of polyunsaturated fatty acid (PUFA) was the same as the calculated average for Australian fish (42.3%), the percentage of n-3 fatty acids was lower (24.4 +/- 5.4% vs. 30.7 +/- 10.1%) and the n-6 fatty acids higher (16.5 +/- 4.5% vs. 11.2 +/- 5.9%), P < 0.001 in each case. The major n-3 PUFA were docosahexaenoic (15.6 +/- 6.3%) and eicosapentaenoic acid (4.3 +/- 1.1%) while the major n-6 PUFA were arachidonic (8.3 +/- 3.2%) and n-6 docosatetraenoic acid (3.1 +/- 1.3%). The second-most abundant class of fatty acid was the saturates (31.6 +/- 3.5%) while the monounsaturates accounted for 17.4 +/- 4.3% of the total fatty acids. The monounsaturate with the highest concentration was octadecenoic acid (11.8 +/- 2.6%). There was a positive correlation between the total lipid content and saturated and monounsaturated fatty acids (r = 0.675 and 0.567, respectively) and a negative correlation between the total lipid content and PUFA (r = 0.774). PMID:9208391

Belling, G B; Abbey, M; Campbell, J H; Campbell, G R

1997-06-01

301

Effects of CO2 Concentration during Growth on Fatty Acid Composition in Microalgae 1  

PubMed Central

The degree of unsaturation of fatty acids was higher in Chlorella vulgaris 11h cells grown with air (low-CO2 cells) than in the cells grown with air enriched with 2% CO2 (high-CO2 cells). The change in the ratio of linoleic acid to ?-linolenic acid was particularly significant. This change of the ratio was observed in four major lipids (monogalactosyldiacylglycerol, digalactosyldiacylglycerol, phosphatidylcholine, and phosphatidylethanolamine). The relative contents of lipid classes were essentially the same both in high-CO2 and low-CO2 cells. After high-CO2 cells were transferred to low CO2 condition, total amount of fatty acids remained constant but the relative content of ?-linolenic acid increased during a 6-hour lag phase in growth with concomitant decreases in linoleic and oleic acids. When low-CO2 cells were transferred to high CO2 condition, total amount of fatty acids and relative content of oleic acid increased significantly. The amount of ?-linolenic acid remained almost constant, while the amounts of palmitic, oleic, and linoleic acids increased. Similar, but smaller, changes in fatty acid compositions were observed in two species of green algae Chlamydomonas reinhardtii and Dunaliella tertiolecta. However, no difference was found in Euglena gracilis, Porphyridium cruentum, Anabaena variabilis, and Anacystis nidulans.

Tsuzuki, Mikio; Ohnuma, Eriko; Sato, Norihiro; Takaku, Tadashi; Kawaguchi, Akihiko

1990-01-01

302

Dietary sandalwood seed oil modifies fatty acid composition of mouse adipose tissue, brain, and liver  

Microsoft Academic Search

Sandalwood (Santalum spicatum) seed oil, which occurs to about 50% of the weight of the seed kernels, contains 30–35% of total fatty acids (FA) as ximenynic\\u000a acid (XMYA). This study was designed to obtain basic information on changes in tissue FA composition and on the metabolic\\u000a fate of XMYA in mice fed a sandalwood seed oil (SWSO)-enriched diet. Female mice

Yandi Liu; Robert B. Longmore

1997-01-01

303

Microstructure and Mechanical Properties of Carboxylated Carbon Nanotubes\\/Poly(L-lactic acid) Composite  

Microsoft Academic Search

Poly(L-lactic acid) (PLLA)\\/MWNTs composites were prepared by mixing solubilized PLLA with solutions of MWNTs treated by four kind of acids. Fourier transform infrared (FT-IR) spectra revealed that carboxyl groups were grafted to the surface of MWNTs. The water solubility showed that the MWNTs treated by HNO 3\\/H2O2 and HNO3\\/H2SO 4 could suspend in the air at room temperature for more

Jiangtao Feng; Jiehe Sui; Wei Cai; Zhiyong Gao

2008-01-01

304

Radionuclide Leaching from Residual Solids Remaining after Acid Dissolution of Composite K East Canister Sludge  

Microsoft Academic Search

Laboratory tests were performed to examine mixed nitric\\/hydrofluoric acid leach treatments for decontaminating dissolver residual solids (KECDVSR24H-2) produced during a 20- to 24-hr dissolution of a composite K East (KE) Basin canister sludge in 95 C 6 M nitric acid (HNOâ). The scope of this testing has been described in Section 4.5 of ''Testing Strategy to Support the Development of

C. H. Delegard; D. E. Rinehart; C. Z. Soderquist; S. K. Fadeff

1999-01-01

305

Growth response and fatty acid composition of juvenile Penaeus vannamei fed different sources of dietary lipid  

Microsoft Academic Search

A study was conducted to evaluate the effects of feeding various sources of dietary lipid on weight gain, feed conversion, survival and fatty acid composition of juvenile Penaeus vannamei. Seven semi-purified diets (35% protein and 3400 kcal of metabolizable energy kg?1) containing defatted, freeze-dried shrimp meal, 1.0% soybean lecithin and 0.5% cholesterol were supplemented with 6.5% of either stearic acid,

Chhorn Lim; Harry Ako; Christopher L. Brown; Kirk Hahn

1997-01-01

306

Characterization of stearic acid modified soy protein isolate resin and ramie fiber reinforced ‘green’ composites  

Microsoft Academic Search

The effects of stearic acid on the physical, tensile, moisture, thermal and micro-structural properties of the soy protein isolate (SPI)-based resin have been investigated. Fully biodegradable, environment-friendly, unidirectional, ramie fiber reinforced ‘green’ composites were also successfully fabricated using SPI and stearic acid modified SPI (MSPI) resins and characterized for their tensile and flexural properties. The fiber\\/resin interfacial shear strength was

Preeti Lodha; Anil N. Netravali

2005-01-01

307

Fatty acid composition of erythrocyte, platelet, and serum lipids in strict vegans  

Microsoft Academic Search

The fatty acid composition of erythrocytes, platelets, and serum lipids was compared between subjects who had been eating\\u000a a strict uncooked vegan diet (“living food”) for years and omnivore controls. The vegan diet contains equal amounts of fat\\u000a but more monounsaturated and polyunsaturated and less saturated fatty acids than the mixed diet of the control group. In vegans,\\u000a the proportion

Jyrki J. Ågren; Marja-Leena Törmälä; Mikko T. Nenonen; Osmo O. Hänninen

1995-01-01

308

Stearoyl-Coenzyme A Desaturase Gene Polymorphism and Milk Fatty Acid Composition in Italian Holsteins  

Microsoft Academic Search

Milk fatty acid composition is a parameter of great interest for evaluation of nutritional quality of milk. Stearoyl-CoA desaturase (SCD) is a key enzyme in mammary lipid metabolism because it is able to add a double bond in the cis ?9-position in a large spectrum of medium- and long-chain fatty acids. A polymorphism with 2 alleles (A and V) in

M. Mele; G. Conte; B. Castiglioni; S. Chessa; N. P. P. Macciotta; A. Serra; A. Buccioni; G. Pagnacco; P. Secchiari

2007-01-01

309

Lithium insertion into the composites of acid-oxidized carbon nanotubes and tin oxide  

Microsoft Academic Search

Lithium intercalation into the composites of acid-oxidized carbon nanotubes and tin oxide was studied in an electrolyte system, 1 M solution of LiPF6 dissolved in a 50:50 mixture by volume of ethylene carbonate (EC) and dimethyl carbonate (DMC). The electrochemical method that is constant current charge–discharge test was used for electrochemical properties of the acid-oxidized carbon nanotubes and tin oxide. The

Zhanhong Yang; Qingwei Wang; Jianli Wang; Zaifeng Li; Shangbin Sang

2007-01-01

310

Effect of Deep-Fat Frying on Phytosterol Content in Oils with Differing Fatty Acid Composition  

Microsoft Academic Search

The objective of this study was to determine the fate of phytosterols in vegetable oils with varying fatty acid composition\\u000a used for frying. High oleic sunflower (HOSun), corn (Corn), hydrogenated soybean (HSBO), expeller pressed soybean (ESBO),\\u000a and expeller pressed low-linolenic acid soybean oil (ELLSBO) were used for frying potato chips in a pilot plant-scale continuous\\u000a fryer. The same oils, and

Jill K. Winkler; K. Warner; Martin T. Glynn

2007-01-01

311

Influence of Tween 80 on the Mycolic Acid Composition of Three Cutaneous Corynebacteria  

Microsoft Academic Search

~~~ ~ ~~~~~~~~~~ Changes in the mycolic acid composition of three cutaneous strains of corynebacteria were caused by the addition of Tween 80 to the culture medium. Gas chromatography-mass spectrometry showed that the carbon chain length and the degree of unsaturation had been affected : the levels of corynomycolic acid with 36 carbon atoms and two double bonds increased significantly.

JACQUELINE CHEVALIER; MARIE-THERESE POMMIER; ANDREE CREMIEUX; GEORGES MICHEL

1988-01-01

312

Seasonal dynamics of fatty acid composition in female northern pike ( Esox lucius L.)  

Microsoft Academic Search

Seasonal changes in the fatty acid composition of neutral and polar lipids were measured in the ovary, liver, white muscle, and adipopancreatic tissue of northern pike. The role of environmental and physiological factors underlying these changes was evaluated. From late summer (August–September) to winter (January–March), the weight percentage of n-3 polyunsaturated fatty acids (especially 22:6n3) declined significantly in the neutral

K. Schwalme; W. C. Mackay; M. T. Clandinin

1993-01-01

313

Chronic Administration of Ursodeoxycholic and Tauroursodeoxycholic Acid Changes Microsomal Membrane Lipid Content and Fatty Acid Composition in Rats  

Microsoft Academic Search

We studied the effect of oral supplementation with ursodeoxycholate (UDCA) or tauroursodeoxycholate (TUDCA) on the lipid content and fatty acid composition of rat hepatic microsomes. UDCA and TUDCA significantly increased the total amount of lipids with the exception of cholesteryl-esters. UDCA significantly increased the triglycerides and phosphatidylethanolamine (PE) microsomal content, and decreased the cholesterol\\/phospholipids and the phosphatidylcholine (PC)\\/PE ratio. Both

Stefano Bellentani; Yan Chong Chao; Ilva Ferretti; Rossana Panini; Claudio Tiribelli

1996-01-01

314

Multifaceted chitin/poly(lactic-co-glycolic) acid composite nanogels.  

PubMed

Cyto-compatible, 80nm sized chitin/PLGA composite nanogels (chit/PLGA-comp NGs) were prepared by regeneration method and characterized. The multifaceted chit/PLGA-comp NGs were surface modified with Au, Fe3O4, CdTe/ZnTe-QDs and umbelliferone, respectively. 185nm sized Au-chit/PLGA-comp NGs, 170nm sized QD-chit/PLGA-comp-NGs and 160nm sized Fe3O4-chit/PLGA-comp-NGs showed RF heating. The QD-chit/PLGA-comp-NGs and 180nm sized umb-chit/PLGA-comp-NGs were well uptaken by Escherichia coli, Staphylococcus aureus and Candida albicans. The chit/PLGA-comp NGs could be useful for microbial monitoring and RF application for cancer therapy. The preliminary data showed that multifaceted chit/PLGA-comp-NGs could be useful for hyperthermia for cancer treatment and microbial labelling and imaging. PMID:24685461

Rejinold, N Sanoj; Biswas, Raja; Chellan, Gopi; Jayakumar, R

2014-06-01

315

Ultrahigh dielectric constant composites based on the oleic acid modified ferroferric oxide nanoparticles and polyvinylidene fluoride  

NASA Astrophysics Data System (ADS)

We studied the dielectric properties of the percolative composites based on polyvinylidene fluoride and oleic acid modified ferroferric oxide nanoparticles. It demonstrates that surface modification not only can prevent the aggregation of the nanoparticles but also can greatly increase the dielectric constant of the composites. The space charge polarization at the interfaces between modified nanoparticles and polymers results in huge enhancement of dielectric constant. The maximum of dielectric constant is up to 24 105 at 100 Hz and the dielectric loss is still controlled in the range of 0-2.5. These composites can be used as the dielectric materials of super-capacitors.

Wang, Tingting; Li, Weiping; Luo, Laihui; Zhu, Yuejin

2013-03-01

316

Lactic acid/wood-based composite material. Part 2: Physical and mechanical performance.  

PubMed

The synthesis of an innovative bio-composite material based on wood and lactic acid oligomers has been reported in Part 1. As a continuation of this previous work, this paper examines the bio-composite material's physical and mechanical performance. Properties were assessed in terms of dimensional stability, decay resistance, leaching, bending, shearing, compression and hardness testing. It has been shown that physical performance of the bio-composite was highly improved, in spite of high leaching mass loss. The mechanical structural properties were not strongly affected, except in decrease of shearing resistance due to the middle lamella degradation. An increase in hardness properties was also noticed. PMID:19473834

Noël, Marion; Mougel, Eric; Fredon, Emmanuel; Masson, Daniel; Masson, Eric

2009-10-01

317

Amino acid composition and antioxidant activities of hydrolysates and peptide fractions from porcine collagen.  

PubMed

The amino acid composition and antioxidant activities of different hydrolysates from porcine collagen were analyzed. The gelatin was hydrolyzed for antioxidative peptides with various proteases, namely papain, protease from bovine pancreas, protease from Streptomyces, and cocktail mixture of protease from bovine pancreas and protease from Streptomyces. The hydrolysates were assessed using methods of DPPH radical-scavenging ability, metal-chelating ability and lipid peroxidation inhibition activity. It was found that the collagen hydrolysates by different protease treatments had different amino acid compositions and antioxidant properties. However, the contents of Hyp and Pro were improved and the content of Gly was decreased in each collagen hydrolysate compared with collagen. The hydrolysate prepared with the cocktail mixture of proteases, which exhibited the highest antioxidant activity, was separated into 6 fractions by gel filtration chromatography. Fraction 2 was further separated by ion exchange chromatography. Fraction 2b with abundant basic amino acids and Fraction 2d which was slightly acidic fractions had higher radical-scavenging and metal-chelating activities, and both Fraction 2b and 2d contained more hydrophobic amino acids. The results confirmed that the antioxidative peptides were rich in Hyp, Pro and Gly, which accounted for half of amino acid composition. This article added further support to the preparation of natural antioxidative peptides from porcine skin collagen. PMID:23064526

Ao, Jing; Li, Bo

2012-10-01

318

Composition of acid tars from sulfuric acid treatment of petroleum oils  

Microsoft Academic Search

In the production of distillate and residual lube oils, the lube stocks may be treated with concentrated sulfuric acid or oleum. This removes unsaturates, aromatics, sulfur compounds, nitrogen compounds and resinous substances, all of which are materials that lower the stability and have a detrimental effect on the service indexes of commercial petroleum oils. Acid tar is formed as a

A. F. Frolov; T. S. Titova; I. V. Karpova; T. L. Denisova

1985-01-01

319

Composite scaffolds of nano calcium deficient hydroxyapatite/multi-(amino acid) copolymer for bone tissue regeneration.  

PubMed

In this study, nano calcium deficient hydroxyapatite (n-DA)/multi-(amino acid) copolymer composite scaffolds were prepared by injection molding foaming method using calcium sulphate dihydrate as a foaming agent. The composite scaffolds showed well interconnected macropores with the pore size of ranging from 100 to 600 ?m, porosity of 81 % and compressive strength of 12 MPa, and the compressive strength obviously affected by the porosity. The composite scaffolds could be slowly degraded in phosphate buffered solution (PBS), which lost its initial weight of 61 w % after immersion into PBS for 12 weeks, and the porosity significantly affected the degradability of the scaffolds. Moreover, it was found that the composite scaffolds could promote the MG-63 cells growth and proliferation, and enhance its alkaline phosphatase activity. The implantation of the scaffolds into the femoral bone of rabbits confirmed that the composite scaffolds were biocompatibitive, degradable, and osteoconductive in vivo. PMID:24488438

Li, Hong; Yang, Lili; Dong, Xieping; Gu, Yifei; Lv, Guoyu; Yan, Yonggang

2014-05-01

320

Thermochromic Organoaminomodified Silica Composite Films Containing Phosphomolybdic Acid  

NASA Astrophysics Data System (ADS)

A novel thermochromic sol-gel film has been prepared for the first time through entrapping phosphomolybdic acid into a kind of inorganic-organic matrix co-hydrolyzed from tetraethylorthosilicate and 3-aminopropyltriethoxysilane. The thus-obtained amorphous nanocomposite film was characterized by IR spectra, UV-vis absorption spectra, XRD, TG-DTA, and ESR. Results show that phosphomolybdate polyanions interact with R-NH +3 cations strongly and disperse homogeneously in the sol-gel matrix. The sol-gel film exhibits thermochromic properties. Annealed from 120 to 180°C, the transparent film changes from pale-yellow to blue. A possible charge-transfer process has been suggested to explain the thermochromism.

Rui Zhang, Tie; Feng, Wei; Lu, Ran; Yan Bao, Chun; Jin Li, Tie; Ying Zhao, Ying; Nian Yao, Jian

2002-06-01

321

Isolation of Arabidopsis mutants with altered seed fatty acid composition  

SciTech Connect

By direct screening of Arabidopsis seed fatty acid methyl esters, we have isolated mutants which are deficient in the elongation of 18:1 to 20:1 and the desaturation of 18:2 to 18:3. Both the elongation and the desaturation mutants, designated MB14 and BL1 respectively, have only 10% of the wild-type levels of 20:1 and 18:3 in their seeds. The intermediate levels of 20:1 and 18:3 in F1 seeds of crosses to the wild type indicate that the level of enzyme is regulating the amount of 20:1 and 18:3 in seeds. Consistent with this observation, the mutations were found to segregate 1:2:1 in F2 seeds. We have found that the 18:2 desaturase mutation is clearly expressed in root phosphatidylcholine.

Lemieux, B.; Browse, J.; Somerville, C. (Dept. of Energy, East Lansing, MI (USA) Washington State Univ., Pullman (USA))

1989-04-01

322

Genome-wide association analyses for fatty acid composition in porcine muscle and abdominal fat tissues.  

PubMed

Fatty acid composition is an important phenotypic trait in pigs as it affects nutritional, technical and sensory quality of pork. Here, we reported a genome-wide association study (GWAS) for fatty acid composition in the longissimus muscle and abdominal fat tissues of 591 White Duroc×Erhualian F2 animals and in muscle samples of 282 Chinese Sutai pigs. A total of 46 loci surpassing the suggestive significance level were identified on 15 pig chromosomes (SSC) for 12 fatty acids, revealing the complex genetic architecture of fatty acid composition in pigs. Of the 46 loci, 15 on SSC5, 7, 14 and 16 reached the genome-wide significance level. The two most significant SNPs were ss131535508 (P?=?2.48×10(-25)) at 41.39 Mb on SSC16 for C20?0 in abdominal fat and ss478935891 (P?=?3.29×10(-13)) at 121.31 Mb on SSC14 for muscle C18?0. A meta-analysis of GWAS identified 4 novel loci and enhanced the association strength at 6 loci compared to those evidenced in a single population, suggesting the presence of common underlying variants. The longissimus muscle and abdominal fat showed consistent association profiles at most of the identified loci and distinct association signals at several loci. All loci have specific effects on fatty acid composition, except for two loci on SSC4 and SSC7 affecting multiple fatness traits. Several promising candidate genes were found in the neighboring regions of the lead SNPs at the genome-wide significant loci, such as SCD for C18?0 and C16?1 on SSC14 and ELOVL7 for C20?0 on SSC16. The findings provide insights into the molecular basis of fatty acid composition in pigs, and would benefit the final identification of the underlying mutations. PMID:23762394

Yang, Bin; Zhang, Wanchang; Zhang, Zhiyan; Fan, Yin; Xie, Xianhua; Ai, Huashui; Ma, Junwu; Xiao, Shijun; Huang, Lusheng; Ren, Jun

2013-01-01

323

Effect of essential and nonessential fatty acids in complex mixture on fatty acid composition of liver lipids.  

PubMed

Linoleate, linolenate, arachidonate, docosahexenoate and six other fatty acids were major components of 24 ester preparations fed as 5% of the diet for 60 days to groups of male white rats. The experiment was designed so as to provide that all major fatty acid components were independent of each other in the sense that the intake of each was poorly correlated with the intake of any of the others. Fatty acid compositions of liver lipids were determined and were related to the composition of the diet lipids. Linolenate and docosahexaenoate contents of diet and tissue revealed the same relationships reported previously from experiments in which individual pure acid esters were added to a fat-free diet. Linoleate, when fed in lipid mixtures, was more effective in raising the linoleate concentration in liver lipids than when fed alone, but this increase did not change the shape of the dose-response curve or the estimated nutritional requirement. Large amounts of fish oil in the diet tended to depress the arachidonate concentration in tissue lipids. PMID:993861

Caster, W O; Andrews, J W; Mohrhauer, H; Holman, R T

1976-12-01

324

Fatty acid compositions of seed oils of Haematostaphis barteri and Ximenia americana.  

PubMed

The fatty acid compositions of the seed oils of Haematostaphis barteri (blood plum) and Ximenia americana (Wild olive) plants were determined by the Gas Chromatography Mass Spectroscopy (GC-MS) technique. H. barteri contained six fatty acids with oleic (69.35%) and stearic (15.40%) the most abundant unsaturated and saturated fatty acids, respectively. Unsaturated higher fatty acids, namely Eicosadienoic (6.92%) and Erucic acid (2.74%) were detected and the total unsaturation for the oil was 79.01%. For X. americana, 10 fatty acids were identified of which seven were unsaturated yielding a total unsaturation of 92.42%. The oil contained essential fatty acids that is, Linoleic (1.34%), Linolenic (10.31%), Arachidonic (0.60%) and varying levels of unsaturated higher fatty acids, namely, Eicosatrienoic (3.39%), Erucic (3.46%) and Nervonic (1.23%) acids. The level of Oleic acid (72.09%) in the oil was close to the value for H. barteri. PMID:11991081

Eromosele, C O; Eromosele, I C

2002-05-01

325

Tetradecylthioacetic acid increases hepatic mitochondrial ?-oxidation and alters fatty acid composition in a mouse model of chronic inflammation.  

PubMed

The administration of tetradecylthioacetic acid (TTA), a hypolipidemic and anti-inflammatory modified bioactive fatty acid, has in several experiments based on high fat diets been shown to improve lipid transport and utilization. It was suggested that increased mitochondrial and peroxisomal fatty acid oxidation in the liver of Wistar rats results in reduced plasma triacylglycerol (TAG) levels. Here we assessed the potential of TTA to prevent tumor necrosis factor (TNF) ?-induced lipid modifications in human TNF? (hTNF?) transgenic mice. These mice are characterized by reduced ?-oxidation and changed fatty acid composition in the liver. The effect of dietary treatment with TTA on persistent, low-grade hTNF? overexpression in mice showed a beneficial effect through decreasing TAG plasma concentrations and positively affecting saturated and monounsaturated fatty acid proportions in the liver, leading to an increased anti-inflammatory fatty acid index in this group. We also observed an increase of mitochondrial ?-oxidation in the livers of TTA treated mice. Concomitantly, there were enhanced plasma levels of carnitine, acetyl carnitine, propionyl carnitine, and octanoyl carnitine, no changed levels in trimethyllysine and palmitoyl carnitine, and a decreased level of the precursor for carnitine, called ?-butyrobetaine. Nevertheless, TTA administration led to increased hepatic TAG levels that warrant further investigations to ascertain that TTA may be a promising candidate for use in the amelioration of inflammatory disorders characterized by changed lipid metabolism due to raised TNF? levels. PMID:21479675

Burri, Lena; Bjørndal, Bodil; Wergedahl, Hege; Berge, Kjetil; Bohov, Pavol; Svardal, Asbjørn; Berge, Rolf K

2011-08-01

326

Dietary n-3 polyunsaturated fatty acids modify fatty acid composition in hepatic and abdominal adipose tissue of sucrose-induced obese rats  

Microsoft Academic Search

The fatty acid profile of hepatocytes and adipocytes is determined by the composition of the dietary lipids. It remains unclear\\u000a which fatty acid components contribute to the development or reduction of insulin resistance. The present work examined the\\u000a fatty acid composition of both tissues in sucrose-induced obese rats receiving fish oil to determine whether the effect of\\u000a dietary (n-3) polyunsaturated

Alfonso Alexander-Aguilera; Silvia Berruezo; Guillermo Hernández-Diaz; Ofelia Angulo; Rosamaria Oliart-Ros

327

General characteristics of Pinus spp. Seed fatty acid compositions, and importance of ?5-olefinic acids in the taxonomy and phylogeny of the genus  

Microsoft Academic Search

The ?5-unsaturated polymethylene-interrupted fatty acid (?5-UPIFA) contents and profiles of gymnosperm seeds are useful chemometric\\u000a data for the taxonomy and phylogeny of that division, and these acids may also have some biomedical or nutritional applications.\\u000a We recapitulate here all data available on pine (Pinus; the largest genus in the family Pinaceae) seed fatty acid (SFA) compositions, including 28 unpublished compositions.

Robert L. Wolff; Frédérique Pédrono; Elodie Pasquier; Anne M. Marpeau

2000-01-01

328

Fatty acid composition and productive traits of broiler fed diets containing conjugated linoleic acid.  

PubMed

An experiment was carried out to evaluate the transfer of dietary CLA to broiler chicken tissues (breast, drumstick meat, skin, and abdominal fat) and its effect on productive traits and on carcass yields of birds. Cobb 500 females (n=360), divided into three groups, received from 22 d to slaughtering age (47 d) a grower diet supplemented with 2% conjugated linoleic acid (CLA) source containing 60% CLA methyl esters (CLA2) or 4% CLA source (CLA4). The control group had no supplementation. The addition of CLA source to chicken diet decreased the content of monounsaturated fatty acid (MUFA) (oleic and palmitoleic acids) in breast and drumstick meat. The deposition of CLA in muscles significantly increased as the dietary CLA increased, whereas only little amounts of CLA were detected in the control group. Arachidonic acid (ARA) content was significantly depressed and linearly related to the addition of CLA to the chicken diet. Other non-CLA polyunsaturated fatty acids (PUFA) were little affected by the dietary CLA supplementation. Saturated fatty acids (myristic and stearic acids) significantly increased about 30% in abdominal fat pad of both treated groups enhancing the firmness of abdominal fat. Productive performances--as well as carcass yields--were similar across dietary treatment of birds. PMID:12943310

Sirri, F; Tallarico, N; Meluzzi, A; Franchini, A

2003-08-01

329

Effects of dietary fatty acid composition on plasma cholesterol.  

PubMed

It should be clear from the preceding sections that the effects of dietary fatty acids on plasma lipids get more complicated the more we try to simplify them! We have presented one argument as to how different fatty acids may interact to impact human plasma lipids. This is by no means an endorsement that ours is the only argument. Nevertheless, a strong case can be made for 14:0 and 18:2 as being the key players in this scenario. The role of palmitic acid seems to be the most controversial. While clearly certain studies do indeed reveal 16:0 to be hypercholesterolemic relative to 18:1, the data from studies suggesting that it behaves similarly to 18:1 are equally compelling. What is certain is that it is erroneous to assume that 16:0 is the major cholesterol-raising SFA simply because it is the most abundant SFA in the diet. Clearly, 18:0 cannot be considered cholesterol-elevating. One is therefore left with the 12-16C SFA. However, 12:0 and 14:0 are only of concern if diets contain palm-kernel, coconut oil or dairy products as major dietary constituents. Accordingly one is left with 16:0 and its response is highly dependent on the metabolic status as well as the age of the subjects being used. While "elderly" hypercholesterolemic humans clearly benefit from decreased 16:0 (and all SFA) consumption, "younger" normocholesterolemic subjects fail to show such clear-cut effects. Additionally, the concomitant levels of dietary cholesterol and 18:2 also have a major bearing on the cholesterolemic response of 16:0 As far as guidelines for the general public are concerned, clearly for people with TC > 225 and LDL-C > 130 mg/dl and/or those who are overweight (i.e. those percieved to be at high risk), the primary emphasis should clearly be on reducing total fat consumption. Decreasing saturated fat consumption will invariably also lower dietary cholesterol consumption. The latter manouver will generally lower TC and LDL-C. Whether the reduction occurs because of the removal of 14:0, or 16:0 and/or dietary cholesterol is a mute point, since most dietary guidelines advocate curtailing intake of animal and dairy products, which will result in reductions of all the SFA. It remains to be established whether life-long adherence to the above dietary guidelines in those subjects with normal cholesterol levels and an absence of the other conventional risk factors for CHD, will result in a subsequent decrease in CHD risk. In the latest NCEP report 39 million Americans were targeted as those who would benefit from reductions in LDL-C, principally by dietary means. This is indeed a very high number. But that leaves almost 220 million Americans! For them the age old recommendation to consume a moderate fat load, maintain ideal body weight and eat a varied and balanced diet would still appear to be the most powerful advice. PMID:8944223

Khosla, P; Sundram, K

1996-01-01

330

Gene transfer of Chlorella vulgaris n-3 fatty acid desaturase optimizes the fatty acid composition of human breast cancer cells  

PubMed Central

Chlorella vulgaris has the gene of n-3 fatty acid desaturase (CvFad3), which can synthesize the precursor of n-3 polyunsaturated fatty acids (PUFAs) or convert n-6 to n-3 PUFAs. The objective of the present study was to examine whether the CvFad3 gene from C. vulgaris can be functionally and efficiently expressed in human breast cancer cells and whether its expression can exert a significant effect on cell fatty acid composition. We inserted the CvFad3 gene into the plasmid pEGFP-C3 to construct the eukaryotic expression vector pEGFP-C3-n-3 and to express the n-3 Fad gene in human breast cancer cells (MCF-7 cells). Transfection of MCF-7 cells with the recombinant vector resulted in a high expression of n-3 fatty acid desaturase. Lipid analysis indicated that the ratio of n-6/n-3 PUFAs was decreased from 6:1 in the control cells to about 1:1 in the cells expressing the n-3 fatty acid desaturase. Accordingly, the CvFad3 gene significantly decreased the ratio of n-6/n-3 PUFAs of the MCF-7 cell membrane. The expression of the CvFad3 gene can decrease cell proliferation and promote cell apoptosis. This study demonstrates that the CvFad3 gene can dramatically balance the ratio of n-6/n-3 PUFAs and may provide an effective approach to the modification of the fatty acid composition of mammalian cells, also providing a basis for potential applications of its transfer in experimental and clinical settings.

Xue, Meilan; Ge, Yinlin; Zhang, Jinyu; Wang, Qing; Hou, Lin

2012-01-01

331

Mapping quantitative trait loci (QTLs) for fatty acid composition in an interspecific cross of oil palm  

PubMed Central

Background Marker Assisted Selection (MAS) is well suited to a perennial crop like oil palm, in which the economic products are not produced until several years after planting. The use of DNA markers for selection in such crops can greatly reduce the number of breeding cycles needed. With the use of DNA markers, informed decisions can be made at the nursery stage, regarding which individuals should be retained as breeding stock, which are satisfactory for agricultural production, and which should be culled. The trait associated with oil quality, measured in terms of its fatty acid composition, is an important agronomic trait that can eventually be tracked using molecular markers. This will speed up the production of new and improved oil palm planting materials. Results A map was constructed using AFLP, RFLP and SSR markers for an interspecific cross involving a Colombian Elaeis oleifera (UP1026) and a Nigerian E. guinneensis (T128). A framework map was generated for the male parent, T128, using Joinmap ver. 4.0. In the paternal (E. guineensis) map, 252 markers (199 AFLP, 38 RFLP and 15 SSR) could be ordered in 21 linkage groups (1815 cM). Interval mapping and multiple-QTL model (MQM) mapping (also known as composite interval mapping, CIM) were used to detect quantitative trait loci (QTLs) controlling oil quality (measured in terms of iodine value and fatty acid composition). At a 5% genome-wide significance threshold level, QTLs associated with iodine value (IV), myristic acid (C14:0), palmitic acid (C16:0), palmitoleic acid (C16:1), stearic acid (C18:0), oleic acid (C18:1) and linoleic acid (C18:2) content were detected. One genomic region on Group 1 appears to be influencing IV, C14:0, C16:0, C18:0 and C18:1 content. Significant QTL for C14:0, C16:1, C18:0 and C18:1 content was detected around the same locus on Group 15, thus revealing another major locus influencing fatty acid composition in oil palm. Additional QTL for C18:0 was detected on Group 3. A minor QTL for C18:2 was detected on Group 2. Conclusion This study describes the first successful detection of QTLs for fatty acid composition in oil palm. These QTLs constitute useful tools for application in breeding programmes.

Singh, Rajinder; Tan, Soon G; Panandam, Jothi M; Rahman, Rahimah Abdul; Ooi, Leslie CL; Low, Eng-Ti L; Sharma, Mukesh; Jansen, Johannes; Cheah, Suan-Choo

2009-01-01

332

Total lipid and fatty acid composition of eight strains of marine diatoms  

NASA Astrophysics Data System (ADS)

Fatty acid composition and total lipid content of 8 strains of marine diatoms ( Nitzschia frustrula, Nitzschia closterium, Nitzschia incerta, Navicula pelliculosa, Phaeodactylum tricornutum, Synedra fragilaroides) were examined. The microalgae were grown under defined conditions and harvested at the late exponential phase. The major fatty acids in most strains were 14?0 (1.0% 6.3%), 16?0 (13.5 26.4%), 16?1n-7 (21.1% 46.3%) and 20?5n-3 (6.5% 19.5%). The polyunsaturated fatty acids 16?2n-4, 16?3n-4, 16?4n-1 and 20?4n-6 also comprised a significant proportion of the total fatty acids in some strains. The characteristic fatty acid composition of diatoms is readily distinguishable from those of other microalgal groups. Significant concentration of the polyunsaturated fatty acid 20?5n-3 (eicosapentaenoic acid) was present in each strain, with the highest proportion in B222 (19.5%).

Liang, Ying; Mai, Kang-Sen; Sun, Shi-Chun

2000-12-01

333

Content and composition of Fatty acids in marine oil omega-3 supplements.  

PubMed

Marine oil omega-3 supplements are among the most frequently consumed dietary supplements in the United States. However, few studies have evaluated the overall fatty acid composition of these products. We investigated the content and composition of fatty acids in 46 commercially available marine oil omega-3 supplements by gas chromatography with flame ionization detection using the 200 m SLB-IL111 ionic liquid column. Seventy-three fatty acid isomers were quantified, including n-6, n-4, n-3, and n-1 polyunsaturated fatty acids and trans isomers of eicosapentaenoic acid (EPA; C20:5n-3) and docosahexaenoic acid (DHA; C22:6n-3), the chromatographic separations of which we report for the first time on the 200 m SLB-IL111 column. Contents of EPA and DHA met their respective label declarations in more than 80% of the products examined. Eleven of the products (24%) carried the Food and Drug Administration's qualified health claim for EPA and DHA omega-3 fatty acids. PMID:25003526

Srigley, Cynthia Tyburczy; Rader, Jeanne I

2014-07-23

334

Fatty acid composition and eating quality of lamb types derived from four diverse breed × production systems  

Microsoft Academic Search

Carcass composition, muscle fatty acids and eating quality of loin chops were examined in ram lambs from four diverse breed × production system groups: pure Welsh Mountain off upland flora, pure Soays off lowland grass, Suffolk crosses off lowland grass and Suffolk crosses off concentrates. The two Suffolk groups had heavier and better muscled carcasses than the others and Soays

A. V. Fisher; M. Enser; R. I. Richardson; J. D. Wood; G. R. Nute; E. Kurt; L. A. Sinclair; R. G. Wilkinson

2000-01-01

335

Influence of clover species in mixtures with grasses on fatty acid composition of mixtures  

Microsoft Academic Search

White clover (WC, Trifolium repens L.) or red clover (RC, Trifolium pratense L.) was grown in mixture with grasses. Samples of the mixtures and pure clovers were taken during three cuts, and the fatty acids (FA) compositions were determined. The clover species had no significant effect on the individual FA contents of the leys (g kg -1 dry matter (DM)),

Langeland Å

336

Apparent longevity-related adaptation of mitochondrial amino acid content is due to nucleotide compositional shifts  

Microsoft Academic Search

Recent studies across animal phyla have suggested a possible link between amino acid compositional shifts and adaptive evolution across mitochondrial proteomes enabling longer lifespans. These studies examined associations of a gradual loss of cysteine (Cys) residues, increased usage of methionine (Met), and increased usage of threonine (Thr), with the evolution of longevity. Here, we examine all three hypotheses in a

Richard W. Jobson; Alexandre Dehne-Garcia; Nicolas Galtier

2010-01-01

337

Carbon isotope composition of low molecular weight hydrocarbons and monocarboxylic acids from Murchison meteorite  

Microsoft Academic Search

Carbon isotopic compositions have been measured for individual hydrocarbons and monocarboxylic acids from the Murchison meteorite, a C2 carbonaceous chondrite which fell in Australia in 1969. With few exceptions, notably benzene, the volatile products are substantially isotopically heavier than their terrestrial counterparts, signifying their extraterrestrial origin. For both classes of compounds, the ratio of C-13 to C-12 decreases with increasing

George Yuen; Neal Blair; D. J. Des Marais; Sherwood Chang

1984-01-01

338

Unexpected amino acid composition of modern Reptilia and its implications in molecular mechanisms of dinosaur extinction  

Microsoft Academic Search

Dinosaur extinction is a great challenge to evolutionary biology. Although accumulating evidence suggests that an abrupt change of environment, such as a long period of low temperature induced by asteroid hit or other disasters, may be responsible for dinosaur extinction, little is known about the underlying molecular mechanisms. By analyzing the amino acid compositions of 13 biological classes, we found

Guang-Zhong Wang; Bin-Guang Ma; Yan Yang; Hong-Yu Zhang

2005-01-01

339

Influence of manganese on morphology and cell wall composition of Aspergillus niger during citric acid fermentation  

Microsoft Academic Search

Morphology and cell wall composition of Aspergillus niger were studied under conditions of manganese sufficient or deficient cultivation in an otherwise citric acid producing medium. Omission of Mn2+ (less than 10-7 M) from the nutrient medium of Aspergillus niger results in abnormal morphological development which is characterized by increased spore swelling, and squat, bulbeous hyphae. Fractionation and analysis of manganese

Monika Kisser; C. P. Kubicek; M. Röhr

1980-01-01

340

FT NIR Raman studies of alginic acid-benzimidazole polymer composite.  

PubMed

New bio-inspired polymer composites of alginic acid and benzimidazole were created and characterized by FT NIR Raman spectroscopy. The obtained films with 1:0.5, 1:1 and 1:1.5 molar ratio are homogeneous, with good mechanical properties. Raman spectra recorded at room temperature revealed that the obtained films are a new compound with a different molecular structure and physical properties compared with pure substrates: alginic acid and benzimidazole. Raman band related to vibration of COOH entity at 1740 cm(-1) of alginic acid disappears in the alginic acid:benzimidazole composites, in which new Raman band related to COO(-) was found. Additionally, characteristic lines observed in polymer composites which may be associated with vibrations of NH groups, can be attributed to the linking of proton to deprotonated N atom in benzimidazole group. Possibility of such proton exchange is a promising property which might facilitate the application of obtained composites to anhydrous proton conducting electrolytes in fuel cells. PMID:20961802

Po?omska, M; Pogorzelec-Glaser, K; Pawlaczyk, C; Pietraszko, A

2011-08-15

341

Fatty acid composition of human milk in atopic Danish mothers1-3  

Microsoft Academic Search

Background: Atopic dermatitis has been related to a disturbed metabolism of polyunsaturated fatty acids (PUFAs). Objective: We tested whether the PUFA composition of breast milk differs significantly between mothers with atopic dermatitis, moth- ers with other types of atopy, and nonatopic mothers. We also in- vestigated whether differences in diet can explain possible observed differences. Design: Mothers with current or

Lotte Lauritzen; Liselotte Brydensholt Halkjær; Tina B Mikkelsen; Sjurdur F Olsen; Kim F Michaelsen; Lotte Loland; Hans Bisgaard

342

Method and composition for neutralizing acidic components in petroleum refining units  

Microsoft Academic Search

Methods and compositions are disclosed for neutralizing acidic components in petroleum refining units. The neutralizing agent comprises a member selected from the group of dimethylaminoethanol and dimethylisopropanolamine. The neutralizing agent may be added directly to the charge, in a reflux line, or directly to the overhead line of the refining unit. In those instances in which sour crude is to

Niu; J. H. Y

1984-01-01

343

Protective effect of Umbelliferone on membranous fatty acid composition in streptozotocin-induced diabetic rats  

Microsoft Academic Search

Umbelliferone (UMB), a natural antioxidant, is benzopyrone in nature, and it is present in the fruits of golden apple and bitter orange. Earlier we evaluated and reported the effect of Umbelliferone on antidiabetic, antioxidant and antihyperlipidemic properties, and this study was designed to evaluate the effect of Umbelliferone on membrane fatty acid composition and histopathology of liver and kidney of

Balakrishnan Ramesh; Periyasamy Viswanathan; Kodukkur Viswanathan Pugalendi

2007-01-01

344

Effect of anion composition of simulated acid rain on nutrient behavior in reclaimed saline soils  

Microsoft Academic Search

The purpose of this study is to demonstrate the relative influence of the anion composition of simulated acid rain on the behavior of nutrients in three reclaimed saline soils. Reclaimed saline soil samples used for this study were collected from surface soils of the Saemangeum and Koheung soils in Korea and the Hachirogata soil in Japan. The Hachirogata soil behaved

Jae-Young Cho; Masaya Nishiyama; Satoshi Matsumoto

2002-01-01

345

Classification of scorpion toxins according to amino acid composition and sequence.  

PubMed

Scorpion venom toxins were systematically classified according to amino acid composition, insertion/deletion events and sequence. The significance of each comparison method and its outcome is discussed in relation to known immunological and structural properties. A general classification of the toxins is proposed that accounts for both the immunological groupings and the differences in mode of action. PMID:6433030

Dufton, M J; Rochat, H

1984-01-01

346

Changes in acyl-coenzyme A pools in sunflower seeds with modified fatty acid composition.  

PubMed

Triacylglycerols (TAGs) are the main reserve product accumulated by oilseeds and they are synthesized by the successive esterification of acyl-CoA derivatives to glycerol molecules through a series of reactions occurring in the endoplasmic reticulum. Acyl-CoA derivatives produced in developing seeds are derived from the de novo plastidial synthesis of fatty acids. This pool of metabolites is also implicated in the elongation of acyl chains due to the action of extraplastidial fatty acid elongases and the incorporation of polyunsaturated fatty acids into TAGs by reticular transacylase enzymes. Analyzing the composition of this pool of metabolites could help us better understand how plant lipid metabolism is regulated. In the present study, we analyzed the size and composition of the acyl-CoA pools in tissues from three sunflower mutants that accumulate oils with modified fatty acid composition. Acyl-CoAs were transformed into their corresponding acyl-etheno-CoA derivatives and analyzed by high performance liquid chromatography with fluorescence detection. We studied developing seeds, germinating cotyledons and leaf tissue to determine how mutations responsible for these traits alter the acyl-CoA pool and hence, the glycerolipid composition of the seeds. Likewise, we analyzed the metabolism of modified TAGs by cotyledons during germination. The metabolic responses of the plant and the effects of the modifications in lipid metabolism that occurred in these mutants are also discussed. PMID:23280039

Aznar-Moreno, Jose A; Martínez-Force, Enrique; Venegas-Calerón, Mónica; Garcés, Rafael; Salas, Joaquín J

2013-03-01

347

Role of Pantothenic Acid as a Modifier of Body Composition in Pigs  

Microsoft Academic Search

Pigs were fed one of four dietary additions of pantothenic acid (PA, 0, 30, 60, and 120 ppm) to determine the effect of PA additions on growth, body composition, and meat quality of pigs fed from 10 to 115 kg of body weight (BW). Fifteen sets (7 barrows, 8 gilts) of four littermate pigs from a high lean strain were

Tim S. Stahly; T. R. Lutz

2001-01-01

348

Ingestion rates and dietary lipids affect growth and fatty acid composition of Dendraster excentricus larvae  

Microsoft Academic Search

This study investigated the effect of single and mixed algal diets on growth, fatty acid composition and ingestion rates for Dendraster excentricus larvae. Larvae were assigned to three single algal diet treatments Isochrysis galbana, Dunaliella tertiolecta or Rhodomonas sp. and four mixed algal diet treatments D. tertiolecta and Rhodomonas, I. galbana and D. tertiolecta, I. galbana and Rhodomonas, D. tertiolecta,

Daniela Schiopu; Sophie B. George; John Castell

2006-01-01

349

Introducing a traditional dairy product Ke?: Chemical, microbiological, and sensorial properties and fatty acid composition  

Microsoft Academic Search

In this study, it was aimed to determine the chemical, biochemical, microbiological and sensorial characteristics and fatty acid composition of Ke?, traditionally produced in Bolu province in Turkey. The information on production of 'Ke?' was collected from Bolu province in Turkey. Moreover, 20 samples were taken from the local bazaars in different periods in Bolu. These samples were taken to

Hayri Co?kun; T. Ako?lu; M. Fatih; Mustafa Kiralan; Ali Bayrak

2009-01-01

350

[Analysis of fatty acid composition of sweat lipids in children and adults with skin disease].  

PubMed

Gas-chromatographic analysis of fatty acid composition of sweat lipids in children and adults with neurodermatitis, atopic dermatitis, and eczema showed that sweat can be used as a new noninvasive biological object for evaluation of lipid metabolism disorders. PMID:11855332

Andrashko, Iu V; Koliadenko, V G; Briuzgina, T S; Prokhorova, M P

2002-01-01

351

Effect of lincomycin treatment on intestinal microflora composition and its bile-acid-metabolizing activity  

Microsoft Academic Search

We have attempted to determine the influence of lincomycin treatment by oral route on the qualitative and quantitative composition of intestinal microflora and on its activity in deconjugating and 7a-dehydroxylating bile acids. Fresh feces from ten patients without preexisting bowel disease were analyzed before and after antibiotic therapy. Our results show that, after antibiotic therapy, the number of microorganisms that

Enrica Canzi; Anna Ceccarelli; Annamaria Ferrari; Edoardo Fesce; Novella Pacini I

1985-01-01

352

Fatty Acid Composition of Mixed-Rumen Bacteria: Effect of Concentration and Type of Forage  

Microsoft Academic Search

The effects of concentration and type of forage in the diet on lipid content and fatty acid (FA) composition of rumen bacteria were studied in 14 goats fitted with duodenal cannulas. The goats were fed a complete maintenance diet containing 40, 70, or 100% chopped forage (dry matter basis) in two equal meals. Forage was either corn stover or alfalfa

P. Bas; H. Archimède; A. Rouzeau; D. Sauvant

2003-01-01

353

Polyaniline/poly acid acrylic thin film composites: a new gamma radiation detector  

SciTech Connect

In this paper, we present a new and straightforward route to prepare polyaniline/poly acid acrylic (PAA) thin film composites in large areas and on almost any surface. This method was developed to improve the mechanical and adherence properties of polyaniline devices used as ionization radiation sensors. The route consists of the combination of the metal oxidant with polymer acid to form a highly homogeneous and viscous paste, which can be easily spread over any surface. In the second step, an aniline acid solution is brought in contact with the dried paste where polymerization occurs, yielding a high homogeneous and conducting polymer composite. The UV-visible absorption and infrared analysis confirm that a polyaniline/PAA complex is obtained. The four-point conductivity measurements show that the composite conductivity {rho} is the order of 5 {omega}{sup -1} cm{sup -1}. Preliminary gamma radiation interaction with the composite shows that the doped composite exhibits a linear response that can be used in the development of real-time radiation sensors for the dose range from 0 to 5000 Gy.

Lima Pacheco, Ana P.; Araujo, Elmo S.; Azevedo, Walter M. de

2003-03-15

354

Use of super acids to digest chrysotile and amosite asbestos in simple mixtures or matrices found in building materials compositions  

SciTech Connect

A composition for converting asbestos-containing material to environmentally benign components is provided. The composition comprises a fluoro acid decomposing agent which can be applied to either amosite-containing thermal insulation or chrysotile-containing fire-proof material or to any asbestos-containing material which includes of chrysotile and amosite asbestos. The fluoro acid decomposing agent includes FP{sub 0}(OH){sub 2}, hexafluorophosphoric acid, a mixture of hydrofluoric and phosphoric acid and a mixture of hexafluorophosphoric acid and phosphoric acid. A method for converting asbestos-containing material to environmentally benign components is also provided.

Sugama, T.; Petrakis, L.; Webster, R.P.

1999-12-21

355

Dipeptidyl peptidase IV inhibitory and antioxidative properties of milk protein-derived dipeptides and hydrolysates.  

PubMed

Selected synthetic dipeptides and milk protein hydrolysates were evaluated for their dipeptidyl peptidase IV (DPP-IV) inhibitory properties, and their superoxide (SO) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities. DPP-IV inhibition was seen with eight out of the twelve dipeptides and 5 of the twelve hydrolysates studied. Trp-Val inhibited DPP-IV, however, inhibition was not observed with the reverse peptide Val-Trp. The most potent hydrolysate inhibitors were generated from casein (CasH2) and lactoferrin (LFH1). Two Trp containing dipeptides, Trp-Val and Val-Trp, and three lactoferrin hydrolysates scavenged DPPH. The dipeptides had higher SO EC(50) values compared to the milk protein hydrolysates (arising from three lactoferrin and one whey protein hydrolysates). Higher molecular mass fractions of the milk protein hydrolysates were associated with the SO scavenging activity. Trp-Val and one lactoferrin hydrolysate (LFH1) were multifunctional displaying both DPP-IV inhibitory and antioxidant (SO and DPPH scavenging) activities. These compounds may have potential as dietary ingredients in the management of type 2 diabetes by virtue of their ability to scavenge reactive oxygen species and to extend the half-life of incretin molecules. PMID:23219487

Nongonierma, Alice B; FitzGerald, Richard J

2013-01-01

356

Iodine?Azide Detection System for Dipeptides in Thin?Layer Chromatography  

Microsoft Academic Search

Dipeptides were derivatized with phenyl thiocarbamyl (PITC) to sulfur?containing compounds. The reaction was performed directly on the chromatographic plate in normal phase chromatography. The detection system was based on an iodine?azide reaction that was induced by sulfur compounds. The procedure involved spraying the developed plate with sodium azide and starch solution and, subsequently, exposing the plate to iodine vapor. Due

Dorota Ka?mierczak; Witold Ciesielski; Katarzyna Dy?ska; Robert Zakrzewski

2008-01-01

357

Conformational preferences, experimental and theoretical vibrational spectra of cyclo(Gly-Val) dipeptide  

NASA Astrophysics Data System (ADS)

The theoretical conformational analysis of cyclic dipeptide, cyclo(glycine-valine), which has anticancer activity, has been performed by molecular mechanics method, in order to examine the energetically optimal conformational states. The relative positions of the side chain residues of the stable conformations of dipeptide were obtained. The obtained geometry of the most stable conformation of the cyclo(Gly-Val) was optimized using DFT method at B3LYP/6-31++G(d,p) level of theory. Afterwards dimeric forms of the dipeptide were formed and energetically preferred conformations of dimers were investigated using the same method and the same level of theory. The experimental IR and micro-Raman spectra of solid cyclo(Gly-Val) were reported for the first time. The vibrational normal modes and associated wavenumbers, IR intensities and Raman activities of the monomeric and dimeric forms of the dipeptide were calculated using DFT method at B3LYP/6-31++G(d,p) level of theory and the results were compared with the experimental data. The total energy distributions (TED) of the vibrational modes were calculated by using Scaled Quantum Mechanical (SQM) analysis. Vibrational assignment was performed on the basis of calculated total energy distribution (TED) of the modes.

Celik, S.; Ozel, A. E.; Akyuz, S.; Kecel, S.; Agaeva, G.

2011-05-01

358

Synthesis of a versatile constrained analogue of dipeptide DG (Asp-Gly).  

PubMed

The synthesis of an orthogonally protected constrained analogue of dipeptide DG (Asp-Gly) is reported exploiting alkylation of a chiral lactam. The versatility of this analogue was proven by removal of t-Boc protecting group, followed by coupling under homogeneous conditions with t-Boc-Arg(Z(2))-Gly, to give a conformationally restricted analogue of RGDG tetrapeptide. PMID:17136507

Galeazzi, R; Marcucci, E; Martelli, G; Natali, D; Orena, M; Rinaldi, S

2008-02-01

359

Plasma and erythrocyte phospholipid fatty acids composition in Serbian hemodialyzed patients.  

PubMed

Dyslipidemia is one of the possible risk factors for advanced atherosclerosis in patients with chronic renal failure. Abnormal phospholipid metabolism may play an important role in the progression of atherosclerosis in patients with renal failure. The aim of this study was to determine specific characteristics of plasma and erythrocyte phospholipid content and fatty acid composition in 37 patients with chronic renal failure on hemodialysis (HD). The results were compared with the characteristics of healthy subjects. Briefly, plasma triglyceride (p < 0.001), total cholesterol (p < 0.05), and total phospholipids (p < 0.01) levels were significantly higher and HDL-cholesterol level significantly lower (p < 0.01) in HD patients. Plasma phosphatidylcholine and phosphatidylethanolamine concentration were significantly higher (p < 0.001) in HD patients. The plasma phospholipid fatty acids composition indicated significantly (p < 0.01) higher level of oleic (18:1 n-9) and lower levels of eicopentaenoic (20:5 n-3 EPA) and docosahexaenoic (22:6 n-3 DHA) acids (p < 0.05). However, in HD patients, the relative concentration of plasma phospholipid n-6 polyunsaturated fatty acid (PUFA) was significantly lower (p < 0.05). The fatty acid composition of erythrocyte phospholipid in HD patients was modified with EPA and DHA levels significantly lowered (p < 0.05). Our results demonstrate an abnormal phospholipid metabolism and deficiency of n-3 PUFA in plasma and erythrocyte phospholipids in hemodialyzed patients. PMID:16703792

Risti?, Vanja; Tepsi?, Vesna; Risti?-Medié, Danijela; Perunici?, Gordana; Rasi?, Zorica; Posti?, Marija; Arsi?, Aleksandra; Blazenci?-Mladenovi?, Vera; Risti?, Gordana

2006-01-01

360

The amino acid composition of the Sutter's Mill CM2 carbonaceous chondrite  

NASA Astrophysics Data System (ADS)

We determined the abundances and enantiomeric compositions of amino acids in Sutter's Mill fragment #2 (designated SM2) recovered prior to heavy rains that fell April 25-26, 2012, and two other meteorite fragments, SM12 and SM51, that were recovered postrain. We also determined the abundance, enantiomeric, and isotopic compositions of amino acids in soil from the recovery site of fragment SM51. The three meteorite stones experienced terrestrial amino acid contamination, as evidenced by the low D/L ratios of several proteinogenic amino acids. The D/L ratios were higher in SM2 than in SM12 and SM51, consistent with rain introducing additional L-amino acid contaminants to SM12 and SM51. Higher percentages of glycine, ?-alanine, and ?-amino-n-butyric acid were observed in free form in SM2 and SM51 compared with the soil, suggesting that these free amino acids may be indigenous. Trace levels of D+L-?-aminoisobutyric acid (?-AIB) observed in all three meteorites are not easily explained as terrestrial contamination, as ?-AIB is rare on Earth and was not detected in the soil. Bulk carbon and nitrogen and isotopic ratios of the SM samples and the soil also indicate terrestrial contamination, as does compound-specific isotopic analysis of the amino acids in the soil. The amino acid abundances in SM2, the most pristine SM meteorite analyzed here, are approximately 20-fold lower than in the Murchison CM2 carbonaceous chondrite. This may be due to thermal metamorphism in the Sutter's Mill parent body at temperatures greater than observed for other aqueously altered CM2 meteorites.

Burton, Aaron S.; Glavin, Daniel P.; Elsila, Jamie E.; Dworkin, Jason P.; Jenniskens, Peter; Yin, Qing-Zhu

2014-03-01

361

Regional background acidity and chemical composition of precipitation in Thailand  

NASA Astrophysics Data System (ADS)

In a joint Thai-Swedish project, within the framework of the IGAC/DEBITS project, precipitation has been collected for chemical analysis on a daily basis since mid-1991 at two sites in the countryside of Thailand. The quality assurance plan includes investigation of the effect of different sampling equipment (including wet-only collectors), sampling time and stability of samples collected in tropical conditions. Consistent results, unbiased by local conditions, have been obtained. The data show striking day-to-day fluctuations, reflecting changes in transport direction and an inhomogeneous distribution of sources. For days with little precipitation the concentration of the components ranges from low to high values while the range is smaller and concentration generally lower during days of high precipitation amount. Mean concentrations are similar at the two stations but the correlation between daily samples is low as can be expected for a distance between the stations of 500 km. A seasonal variation could not be significantly determined. The best correlation between components is found for H + and SO 42- , mutually between Na + Cl -, Mg 2+ and Ca 2+ and between NH 4+ and NO 3-. Absence of correlation between Ca 2+ and SO 42- suggests that SO 42- is not soil derived. The samples are generally slightly acidic which, stochiometrically, can be explained as an imbalance between acidifying components in modest to low concentration and neutralizing components in somewhat lower concentration. The concentrations are lower than those previously reported from stations in eastern and southern Asia, except for some very remote locations.

Granat, L.; Suksomsankh, K.; Simachaya, S.; Tabucanon, M.; Rodhe, H.

362

[The study of fatty acid composition of terpug during preserve's production].  

PubMed

The results of research of fatty acids composition of Terpug, during the producing of preserves in souses and aspics, which are got using the method of gas liquid chromatography. It is known that during the marinating process of Terpug there is no the oxidizing destruction of lipids of muscular tissue of fish. The kind of aspic influences on fatty acids composition of preserves of Terpug. The process of ripening and storing of preserves of fish leads to the diffusion, in particular the sorption of components of aspic with fish. This process increases nutrient density, proportion W3 cem/W6 cem acids it is close to optimal meaning, testifies to high biological value of preserves. PMID:12872659

Cherevan, E I; Tsybul'ko, E I

2003-01-01

363

Effect of nitrogen concentration on lipid productivity and fatty acid composition of Monoraphidium sp.  

PubMed

Green algae, Monoraphidium sp. T4X, was isolated locally, in New Delhi, India and identified as a potential source of biofuel. The study focuses on the effect of nutritional amendments and their uptake rates with respect to growth and change in fatty acid composition of the species. The lipid productivity and fatty acid profile were investigated and compared under six different nitrogen concentrations. Of the tested concentrations, cultures with nitrate concentration 0.36 g/l exhibited higher lipid productivity (0.18 g/l/day) with optimum content of all fatty acid compositions (SFA=37.22, MUFA=39.19, PUFA=23.60) with appropriate biodiesel properties. The right phase for harvesting microalgae was also investigated on the basis of the growth curve. PMID:24360518

Dhup, Saumya; Dhawan, Vibha

2014-01-01

364

Acid-functionalized polysilsesquioxane-nafion composite membranes with high proton conductivity and enhanced selectivity.  

PubMed

A series of new Nafion-based composite membranes have been prepared via an in situ sol-gel reaction of 3-(trihydroxylsilyl)propane-1-sulfonic acid and solution casting method. The morphological structure, ion-exchange capacity, water uptake, proton conductivity, and methanol permeability of the resulting composite membranes have been extensively investigated as functions of the content of sulfopropylated polysilsesquioxane filler, temperature, and relative humidity. Unlike the conventional Nafion/silica composites, the prepared membranes exhibit an increased water uptake and associated enhancement in proton conductivity compared to unmodified Nafion. In particular, considerably high proton conductivities at 80 and 120 degrees C under 30% relative humidity have been demonstrated in the composite membranes, which are over 2 times greater than that of Nafion. In addition to a remarkable improvement in proton conductivity, the composite membranes display lower methanol permeability and superior electrochemical selectivities in comparison to the pure Nafion membrane. These unique properties could be exclusively credited to the presence of pendant sulfonic acid groups in the filler, which provides fairly continuous proton-conducting pathways between filler and matrix in the composite membranes and thus facilitates the proton transport without the anticipated trade-off between conductivity and selectivity. This work opens new opportunities of tailoring the properties of Nafion-the benchmark fuel cell membrane-to obviate its limitations and enhance the conductive properties at high temperature/low humidity and in direct methanol fuel cells. PMID:20356129

Xu, Kui; Chanthad, Chalatorn; Gadinski, Matthew R; Hickner, Michael A; Wang, Qing

2009-11-01

365

Analysis of the correlation between dipeptides and taste differences among soy sauces by using metabolomics-based component profiling.  

PubMed

Characterizing the relationships between the components and taste differences among soy sauces can help evaluate and improve the quality of soy sauces. Although previous studies have reported that certain taste-active dipeptides, the relationships between taste differences and dipeptides of soy sauces are unknown. Therefore, our objective in this study was to investigate the correlations between the dipeptides and the taste differences among soy sauces. To analyze the dipeptides, we constructed an analytical method using liquid chromatography/tandem mass spectrometry (LC/MS/MS) in multiple reaction monitoring mode. Based on this method, we detected 237 dipeptides, the largest number ever detected in soy sauce research. Next, orthogonal projections to latent structures regressions were performed. The data matrix of components, including dipeptides and other low-molecular-weight hydrophilic components obtained from gas chromatography/mass spectrometry (GC/MS), served as explanatory variables (366 in total), whereas a sensory data matrix obtained using quantitative descriptive analysis served as the response variable. The accuracy of models for the sweetness and saltiness differences constructed using the LC/MS/MS and GC/MS data matrix were higher than did models constructed using only the GC/MS data matrix. As a result of investigation of the correlation between the dipeptides and taste differences among soy sauces by using variable importance in the projection (VIP) score, many dipeptides showed the high correlation with taste differences. Specifically, Ile-Gln, Pro-Lys, Ile-Glu, Thr-Phe, and Leu-Gln showed the high VIP score on sweet differences. This study is the first report that reveals the correlations between the dipeptides and taste differences among soy sauces. PMID:24491915

Yamamoto, Shinya; Shiga, Kazuki; Kodama, Yukako; Imamura, Miho; Uchida, Riichiro; Obata, Akio; Bamba, Takeshi; Fukusaki, Eiichiro

2014-07-01

366

Fatty acid and hydrocarbon composition in tropical marine Shewanella amazonensis strain SB2B(T).  

PubMed

Shewanella amazonensis strain SB2B(T) is an isolate from shallow-water marine sediments derived from the Amazon River delta. This bacterium contained a long-chain polyunsaturated hydrocarbon, all-cis -3,6,9,12,16,19,22,25,28 hentriacontanonaene (C31:9), constituting 1-2% of the total fatty acid methyl ester and hydrocarbon fraction, which was produced dependently of decreased growth temperature. Analysis of its cellular fatty acid composition demonstrated that isopentadecanoic acid was the major fatty acid component and that all the main monounsaturated fatty acids had straight chains with a cis configuration. However, monoenoic cyclopropyl fatty acids, which were previously reported to be present in this bacterium, were not detected by mass spectrometric analysis. The growth temperature affected the content of ?9-cis -hexadecenoic [16:1(?9c)], palmitic, and heptadecanoic acids. These results suggest that C31:9, as well as 16:1(?9c) might be involved in adaptation to low temperature in S. amazonensis strain SB2B(T) . Our result suggests that polyunsaturated fatty acid synthase protein complex may be involved in synthesis of C31:9 but not in production of eicosapentaenoic acid. PMID:21656813

Motoigi, Taro; Okuyama, Hidetoshi

2011-10-01

367

Elevated hepatic fatty acid elongase-5 activity affects multiple pathways controlling hepatic lipid and carbohydrate composition*s?  

PubMed Central

Hepatic fatty acid elongase-5 (Elovl-5) plays an important role in long chain monounsaturated and polyunsaturated fatty acid synthesis. Elovl-5 activity is regulated during development, by diet, hormones, and drugs, and in chronic disease. This report examines the impact of elevated Elovl-5 activity on hepatic function. Adenovirus-mediated induction of Elovl5 activity in livers of C57BL/6 mice increased hepatic and plasma levels of dihomo-?-linolenic acid (20:3,n-6) while suppressing hepatic arachidonic acid (20:4,n-6) and docosahexaenoic acid (22:6,n-3) content. The fasting-refeeding response of peroxisome proliferator-activated receptor ?-regulated genes was attenuated in mice with elevated Elovl5 activity. In contrast, the fasting-refeeding response of hepatic sterol-regulatory element binding protein-1 (SREBP-1)-regulated and carbohydrate-regulatory element binding protein/Max-like factor X-regulated genes, Akt and glycogen synthase kinase (Gsk)-3? phosphorylation, and the accumulation of hepatic glycogen content and nuclear SREBP-1 were not impaired by elevated Elovl5 activity. Hepatic triglyceride content and the phosphorylation of AMP-activated kinase ? and Jun kinase 1/2 were reduced by elevated Elovl5 activity. Hepatic phosphoenolpyruvate carboxykinase expression was suppressed, while hepatic glycogen content and phosphorylated Gsk-3? were significantly increased, in livers of fasted mice with increased Elovl5 activity. As such, hepatic Elovl5 activity may affect hepatic glucose production during fasting. In summary, Elovl5-induced changes in hepatic fatty acid content affect multiple pathways regulating hepatic lipid and carbohydrate composition.

Wang, Yun; Torres-Gonzalez, Moises; Tripathy, Sasmita; Botolin, Daniela; Christian, Barbara; Jump, Donald B.

2008-01-01

368

Fatty acid composition in matrix vesicles and in microvilli from femurs of chicken embryos revealed selective recruitment of fatty acids.  

PubMed

Hypertrophic chondrocytes participate in matrix mineralization by releasing matrix vesicles (MVs). These MVs, by accumulating Ca(2+) and phosphate initiate the formation of hydroxyapatite. To determine the types of lipids essential for mineralization, we analyzed fatty acids (FAs) in MVs, microvilli and in membrane fractions of chondrocytes isolated from femurs of chicken embryos. The FA composition in the MVs was almost identical to that in microvilli, indicating that the MVs originated from microvilli. These fractions contained more monounsaturated FAs especially oleic acid than in membrane homogenates of chondrocytes. They were enriched in 5,8,11-eicosatrienoic acid (20:3n-9), in eicosadienoic acid (20:2n-6), and in arachidonic acid (20:4n-6). In contrast, membrane homogenates from chondrocytes were enriched in 20:1n-9, 18:3n-3, 22:5n-3 and 22:5n-6. Due to their relatively high content in MVs and to their selective recruitment within microvilli from where MV originate, we concluded that 20:2n-6 and 20:3n-9 (pooled values), 18:1n-9 and 20:4n-6 are essential for the biogenesis of MVs and for bone mineralization. PMID:24685481

Abdallah, Dina; Hamade, Eva; Merhi, Raghida Abou; Bassam, Badran; Buchet, René; Mebarek, Saida

2014-04-18

369

Lactic acid fermentation by cells immobilised on various porous cellulosic materials and their alginate/poly-lactic acid composites.  

PubMed

Porous delignified cellulose (or tubular cellulose, abbr. TC) from Indian Mango (Mangifera indica) and Sal (Shorea robusta) wood and Rice husk, and TC/Ca-alginate/polylactic acid composites, were used as Lactobacillus bulgaricus immobilisation carriers leading to improvements in lactic acid fermentation of cheese whey and synthetic lactose media, compared to free cells. Specifically, shorter fermentation rates, higher lactic acid yields (g/g sugar utilised) and productivities (g/Ld), and higher amounts of volatile by-products were achieved, while no significant differences were observed on the performance of the different immobilised biocatalysts. The proposed biocatalysts are of food grade purity, cheap and easy to prepare, and they are attractive for bioprocess development based on immobilised cells. Such composite biocatalysts may be used for the co-immobilisation of different microorganisms or enzymes (in separate layers of the biocatalyst), to efficiently conduct different types of fermentations in the same bioreactor, avoiding inhibition problems of chemical or biological (competition) nature. PMID:24690466

Kumar, Mrinal Nishant; Gialleli, Angelika-Ioanna; Masson, Jean Bernard; Kandylis, Panagiotis; Bekatorou, Argyro; Koutinas, Athanasios A; Kanellaki, Maria

2014-08-01

370

The characterization and photochromism of copolymer composite films containing phosphotungstic acid  

NASA Astrophysics Data System (ADS)

The composite film (PWA/VPMA) was synthesized by introduced phosphotungstic acid (PWA) into the poly(vinylpyrrolidone and methyl acrylate) (VPMA), which was copolymerized with vinylpyrrolidone (VP) and methyl acrylate (MA) monomer. The microstructure, thermal stability, photochromic properties and mechanism were investigated via atomic force microscopy, Fourier transform infrared spectroscopy, differential thermal analysis, differential scanning calorimetry, ultraviolet-visible spectra and electron resonance spectra. The results indicated that the Keggin geometry of PWA and the basic structure of VPMA were not destroyed in the composite process. After PWA particles were introduced into the VPMA, the thermal stability of composite film was lowered due to the interaction between PWA and VPMA. Irradiated with UV light, PWA/VPMA composite film changed from colorless to blue and showed reversible photochromism. The appearance of W5+ in ESR spectra indicated that the photo-reduction process between PWA and copolymer matrix occurred according to the proton transfer mechanism.

Peng, Xin-Jing; Zhang, Yu; Feng, Wei; Ai, Li-Mei; Chen, Jie; Zhang, Feng-jun

2013-06-01

371

Egg fatty acid composition from lake trout fed two Lake Michigan prey fish species.  

PubMed

We previously demonstrated that there were significant differences in the egg thiamine content in lake trout Salvelinus namaycush fed two Lake Michigan prey fish (alewife Alosa pseudoharengus and bloater Coregonus hoyi). Lake trout fed alewives produced eggs low in thiamine, but it was unknown whether the consumption of alewives affected other nutritionally important components. In this study we investigated the fatty acid composition of lake trout eggs when females were fed diets that resulted in different egg thiamine concentrations. For 2 years, adult lake trout were fed diets consisting of four combinations of captured alewives and bloaters (100% alewives; 65% alewives, 35% bloaters; 35% alewives, 65% bloaters; and 100% bloaters). The alewife fatty acid profile had higher concentrations of arachidonic acid and total omega-6 fatty acids than the bloater profile. The concentrations of four fatty acids (cis-13, 16-docosadienoic, eicosapentaenoic, docosapentaenoic, and docosahexaenoic acids) were higher in bloaters than in alewives. Although six fatty acid components were higher in lake trout eggs in 2001 than in 2000 and eight fatty acids were lower, diet had no effect on any fatty acid concentration measured in lake trout eggs in this study. Based on these results, it appears that egg fatty acid concentrations differ between years but that the egg fatty acid profile does not reflect the alewife-bloater mix in the diet of adults. The essential fatty acid content of lake trout eggs from females fed alewives and bloaters appears to be physiologically regulated and adequate to meet the requirements of developing embryos. PMID:20218501

Honeyfield, Dale C; Fitzsimons, John D; Tillitt, Donald E; Brown, Scott B

2009-12-01

372

Protective effect of Umbelliferone on membranous fatty acid composition in streptozotocin-induced diabetic rats.  

PubMed

Umbelliferone (UMB), a natural antioxidant, is benzopyrone in nature, and it is present in the fruits of golden apple and bitter orange. Earlier we evaluated and reported the effect of Umbelliferone on antidiabetic, antioxidant and antihyperlipidemic properties, and this study was designed to evaluate the effect of Umbelliferone on membrane fatty acid composition and histopathology of liver and kidney of control and streptozotocin (STZ) diabetic rats. Male albino Wistar rats (180-200 g) were made diabetic by an intraperitonial administration of STZ (40 mg/kg). The control and diabetic rats were treated with Umbelliferone and glibenclamide dissolved in 10% dimethyl sulfoxide for 45 days. Diabetic rats had decreased insulin and increased glucose, and increased levels of thiobarbituric acid reactive substances, lipid hydroperoxides and conjugated dienes. The levels of palmitic, stearic and oleic acids increased and the levels of linolenic and arachidonic acids decreased in diabetic rats as compared with control rats. Thus, the saturated fatty acids and monounsaturated fatty acids increased and the polyunsaturated fatty acids decreased in diabetic rats. Diabetic rats had decreased liver weight and increased activities of alanine transaminase and aspartate transaminase; increased kidney weight and urine albumin, and decreased levels of urea, uric acid and creatinine in the urine. Histopathological studies of liver and kidney in diabetic rats showed fatty changes surrounding portal triad; enlargement of lining cells of tubules, fatty infiltration, large area of hemorrhage and lymphocyte infiltration. Treatment with Umbelliferone and glibenclamide reversed these changes to near normalcy. Our results showed that Umbelliferone has a protective effect on membrane fatty acid composition of liver and kidney as supported by antioxidant and antihyperlipidemic effects of Umbelliferone reported earlier as evidenced by improved histopathological changes, hepatic and nephritic markers, indicating recovery from the risk of diabetic complications. PMID:17477917

Ramesh, Balakrishnan; Viswanathan, Periyasamy; Pugalendi, Kodukkur Viswanathan

2007-07-01

373

Effects of feeding camelina (seeds or meal) on milk fatty acid composition and butter spreadability.  

PubMed

The nutritional and rheological properties of butter depend on the fatty acid composition of milk. Therefore, feeding oilseeds rich in unsaturated fatty acids is likely to affect butter properties. The aim of this trial was to examine to what extent feeding the linolenic acid-rich cruciferous plant camelina can affect the fatty acid composition of dairy products and the properties of butter. A control diet composed of 60% corn silage-based ration and completed with high-energy and nitrogenous concentrates was compared with 2 experimental diets designed to provide the same amount of polyunsaturated fatty acids via either camelina seed (630 g/d, CS diet) or camelina meal (2 kg/d, CM diet). The diets were isoenergetic and isonitrogenous. The trial followed a double 3 x 3 Latin-square design with 4-wk periods on 6 Holstein dairy cows. The camelina diets tended to decrease dry matter intake but did not have a significant effect on milk production. They generated a slight decrease in milk protein and a strong decrease in milk fat yield and content. The CM diet led to a stronger decrease in fat content. Camelina generated a greater proportion of monounsaturated fatty acids, notably C18:1 trans isomers, including trans-10 and trans-11 C18:1, which increased by 11.0- and 2.6-fold, respectively, with the CM diet. Camelina also led to an increase in conjugated linoleic acids, particularly rumenic acid, cis-9, trans-11 C18:2. Camelina did not affect parameters of buttermaking except churning time with milk from CM fed cows, which was longer. The butters of camelina diets were softer at all temperatures tested, especially with the CM diet. In conclusion, feeding camelina can modify milk fatty acid profile and butter spreadability. PMID:17954754

Hurtaud, C; Peyraud, J L

2007-11-01

374

New insight into the SSC8 genetic determination of fatty acid composition in pigs  

PubMed Central

Background Fat content and fatty acid composition in swine are becoming increasingly studied because of their effect on sensory and nutritional quality of meat. A QTL (quantitative trait locus) for fatty acid composition in backfat was previously detected on porcine chromosome 8 (SSC8) in an Iberian x Landrace F2 intercross. More recently, a genome-wide association study detected the same genomic region for muscle fatty acid composition in an Iberian x Landrace backcross population. ELOVL6, a strong positional candidate gene for this QTL, contains a polymorphism in its promoter region (ELOVL6:c.-533C?acids in muscle and adipose tissues. Here, a combination of single-marker association and the haplotype-based approach was used to analyze backfat fatty acid composition in 470 animals of an Iberian x Landrace F2 intercross genotyped with 144 SNPs (single nucleotide polymorphisms) distributed along SSC8. Results Two trait-associated SNP regions were identified at 93 Mb and 119 Mb on SSC8. The strongest statistical signals of both regions were observed for palmitoleic acid (C16:1(n-7)) content and C18:0/C16:0 and C18:1(n-7)/C16:1(n-7) elongation ratios. MAML3 and SETD7 are positional candidate genes in the 93 Mb region and two novel microsatellites in MAML3 and nine SNPs in SETD7 were identified. No significant association for the MAML3 microsatellite genotypes was detected. The SETD7:c.700G?>?T SNP, although statistically significant, was not the strongest signal in this region. In addition, the expression of MAML3 and SETD7 in liver and adipose tissue varied among animals, but no association was detected with the polymorphisms in these genes. In the 119 Mb region, the ELOVL6:c.-533C?>?T polymorphism showed a strong association with percentage of palmitic and palmitoleic fatty acids and elongation ratios in backfat. Conclusions Our results suggest that the polymorphisms studied in MAML3 and SETD7 are not the causal mutations for the QTL in the 93 Mb region. However, the results for ELOVL6 support the hypothesis that the ELOVL6:c.-533C?>?T polymorphism has a pleiotropic effect on backfat and intramuscular fatty acid composition and that it has a role in the determination of the QTL in the 119 Mb region.

2014-01-01

375

Chronic Risperidone Treatment Preferentially Increases Rat Erythrocyte and Prefrontal Cortex Omega-3 Fatty Acid Composition: Evidence for Augmented Biosynthesis  

PubMed Central

Prior clinical studies suggest that chronic treatment with atypical antipsychotic medications increase erythrocyte and postmortem prefrontal cortex (PFC) omega-3 fatty acid composition in patients with schizophrenia (SZ). However, because human tissue phospholipid omega-3 fatty acid composition is potentially influenced by multiple extraneous variables, definitive evaluation of this putative mechanism of action requires an animal model. In the present study, we determined the effects of chronic treatment with the atypical antipsychotic risperidone (RISP, 3.0 mg/kg/d) on erythrocyte and PFC omega-3 fatty acid composition in rats maintained on a diet with or without the dietary omega-3 fatty acid precursor, alpha-linolenic acid (ALA, 18:3n-3). Chronic RISP treatment resulted in therapeutically-relevant plasma RISP and 9-OH-RISP concentrations (18±2.6 ng/ml), and significantly increased erythrocyte docosahexaenoic acid (DHA, 22:6n-3, +22%, p=0.0003) and docosapentaenoic acid (22:5n-3, +18%, p=0.01) composition, and increased PFC DHA composition (+7%, p=0.03) in rats maintained on the ALA+ diet. In contrast, chronic RISP did not alter erythrocyte or PFC omega-3 fatty acid composition in rats maintained on the ALA? diet. Chronic RISP treatment did not alter erythrocyte or PFC arachidonic acid (AA, 20:4n-6) composition. These data demonstrate that chronic RISP treatment significantly augments ALA-DHA biosynthesis, and preferentially increases peripheral and central membrane omega-3 fatty acid composition. Augmented omega-3 fatty acid biosynthesis and membrane composition represents a novel mechanism of action that may contribute in part to the efficacy of RISP in the treatment of SZ.

McNamara, Robert K.; Able, Jessica A.; Jandacek, Ronald; Rider, Therese; Tso, Patrick

2009-01-01

376

Preparation and characterization of dry method esterified starch/polylactic acid composite materials.  

PubMed

Corn starch and maleic anhydride were synthesized from a maleic anhydride esterified starch by dry method. Fourier transform infrared spectroscopy (FTIR) was used for the qualitative analysis of the esterified starches. The reaction efficiency of dry method esterified starch reached 92.34%. The dry method esterified starch was blended with polylactic acid (PLA), and the mixture was melted and extruded to produce the esterified starch/polylactic acid (ES/PLA) composites. The degree of crystallinity of the ES/PLA was lower than that of the NS/PLA, indicating that the relative dependence between these two components of starch and polylactic acid was enhanced. Scanning electron microscopy (SEM) indicated that the dry method esterified starch increased the two-phase interface compatibility of the composites, thereby improving the tensile strength, bending strength, and elongation at break of the ES/PLA composite. The introduction of a hydrophobic ester bond and increase in interface compatibility led to an increase in ES/PLA water resistance. Melt index determination results showed that starch esterification modification had improved the melt flow properties of starch/PLA composite material. Strain scanning also showed that the compatibility of ES/PLA was increased. While frequency scanning showed that the storage modulus and complex viscosity of ES/PLA was less than that of NS/PLA. PMID:24315947

Zuo, Yingfeng; Gu, Jiyou; Yang, Long; Qiao, Zhibang; Tan, Haiyan; Zhang, Yanhua

2014-03-01

377

Fatty Acid Composition of Human Follicular Fluid Phospholipids and Fertilization Rate in Assisted Reproductive Techniques  

PubMed Central

Background: Fatty acids are known to be critically important in multiple biological functions. Phospholipid fatty acids of follicular fluid, an important microenvironment for the development of oocytes, may contribute to the women’s fertility and the efficacy of assisted reproduction techniques. The aim of this study was to investigate the effect of fatty acid composition of follicular fluid phospholipids on women undergoing assisted reproductive techniques. Methods: Follicular fluid samples were obtained from 100 patients, referred to Tabriz Alzahra Hospital. Seventy-nine subjects underwent in vitro fertilization (IVF) and the remaining 21 underwent intracytoplasmic sperm injection (ICSI). Total lipid of follicular fluid was extracted and fatty acids were analyzed by gas-liquid chromatography. Results: Saturated fatty acids (SFA, P = 0.002) and the ratio of SFA to polyunsaturated fatty acids (P = 0.001) were correlated negatively with a number of mature oocytes after age adjustment. Linoleic acid (P = 0.006) was positively correlated, while the level of arachidonic acid was negatively correlated with fertility percentage after adjustment for body mass index, sperm count, sperm motility. Conclusion: Since phospholipids are one of the major components of lipid metabolism, the results of this study highlight the importance of this component in follicular fluid lipid metabolism. Consequently, it is proposed as an index in determination of the rate of success in assisted reproductive techniques such as IVF/ICSI.

Shaaker, Maghsod; Rahimipour, Ali; Nouri, Mohammad; Khanaki, Korosh; Darabi, Masoud; Farzadi, Laya; Shahnazi, Vahideh; Mehdizadeh, Amir

2012-01-01

378

Metabolic efficiency and amino acid composition in the proteomes of Escherichia coli and Bacillus subtilis  

PubMed Central

Biosynthesis of an Escherichia coli cell, with organic compounds as sources of energy and carbon, requires approximately 20 to 60 billion high-energy phosphate bonds [Stouthamer, A. H. (1973) Antonie van Leeuwenhoek 39, 545–565]. A substantial fraction of this energy budget is devoted to biosynthesis of amino acids, the building blocks of proteins. The fueling reactions of central metabolism provide precursor metabolites for synthesis of the 20 amino acids incorporated into proteins. Thus, synthesis of an amino acid entails a dual cost: energy is lost by diverting chemical intermediates from fueling reactions and additional energy is required to convert precursor metabolites to amino acids. Among amino acids, costs of synthesis vary from 12 to 74 high-energy phosphate bonds per molecule. The energetic advantage to encoding a less costly amino acid in a highly expressed gene can be greater than 0.025% of the total energy budget. Here, we provide evidence that amino acid composition in the proteomes of E. coli and Bacillus subtilis reflects the action of natural selection to enhance metabolic efficiency. We employ synonymous codon usage bias as a measure of translation rates and show increases in the abundance of less energetically costly amino acids in highly expressed proteins.

Akashi, Hiroshi; Gojobori, Takashi

2002-01-01

379

Comparative study on free amino acid composition of wild edible mushroom species.  

PubMed

A comparative study on the amino acid composition of 11 wild edible mushroom species (Suillus bellini, Suillus luteus, Suillus granulatus, Tricholomopsis rutilans, Hygrophorus agathosmus, Amanita rubescens, Russula cyanoxantha, Boletus edulis, Tricholoma equestre, Fistulina hepatica, and Cantharellus cibarius) was developed. To define the qualitative and quantitative profiles, a derivatization procedure with dabsyl chloride was performed, followed by HPLC-UV-vis analysis. Twenty free amino acids (aspartic acid, glutamic acid, asparagine, glutamine, serine, threonine, glycine, alanine, valine, proline, arginine, isoleucine, leucine, tryptophan, phenylalanine, cysteine, ornithine, lysine, histidine, and tyrosine) were determined. B. edulis and T. equestre were revealed to be the most nutritional species, whereas F. hepatica was the poorest. The different species exhibited distinct free amino acid profiles. The quantification of the identified compounds indicated that, in a general way, alanine was the major amino acid. The results show that the analyzed mushroom species possess moderate amino acid contents, which may be relevant from a nutritional point of view because these compounds are indispensable for human health. A combination of different mushroom species in the diet would offer good amounts of amino acids and a great diversity of palatable sensations. PMID:18942845

Ribeiro, Bárbara; Andrade, Paula B; Silva, Branca M; Baptista, Paula; Seabra, Rosa M; Valentão, Patrícia

2008-11-26

380

The lipid composition of highly differentiated human hepatomas, with special reference to fatty acids.  

PubMed Central

The lipid compositions of homogenates and microsomal fractions derived from surgical samples of highly differentiated human hepatoma, morphologically normal regions outside the tumours and from normal livers were analysed. A few enzyme activities were also assayed. Hepatoma microsomes demonstrated considerably lowered levels of cytochromes P-450 and b5. Hepatoma homogenates exhibited increased levels of cholesterol, normal amounts of dolichyl-P and slightly lowered levels of total phospholipid. The levels of dolichol, dolichol ester and ubiquinone in hepatoma homogenates were prominently decreased. In tumour microsomes the levels of cholesterol and dolichyl phosphate were increased considerably while the levels of phospholipid and dolichol were lowered. The phospholipid composition of tumour homogenates was roughly similar to that of control tissue. In tumour microsomes the relative amounts of phosphatidylserine and phosphatidylinositol were about 30% decreased, whereas the major phospholipids showed minor increases in amount. The rate and pattern of incorporation of [3H]glycerol into individual phospholipids in liver slices from control and hepatoma tissue did not differ to any larger extent. The fatty acid composition of tumour homogenates exhibited minor differences in comparison to the control with the greatest changes in the sphingomyelin fraction. In hepatoma microsomes the fatty acid compositions of the major phospholipids were altered moderately, with evident decreases in the relative amounts of the long-chain polyunsaturated fatty acids. In hepatoma homogenates the fatty acid composition of dolichol esters differed only slightly from the control pattern. These results indicate that the major disturbance in the lipid metabolism of highly differentiated hepatomas is localized to the mevalonate pathway, thus affecting mainly the levels of cholesterol, dolichol and ubiquinone.

Eggens, I.; Backman, L.; Jakobsson, A.; Valtersson, C.

1988-01-01

381

The influence of feeding linoleic, gamma-linolenic and docosahexaenoic acid rich oils on rat brain tumor fatty acids composition and fatty acid binding protein 7 mRNA expression  

Microsoft Academic Search

BACKGROUND: Experimental studies indicate that gamma linolenic acid (GLA) and docosahexaenoic acid (DHA) may inhibit glioma cells growth but effects of oral consumption of these fatty acids on brain tumor fatty acid composition have not been determined in vivo. METHODS: GLA oil (GLAO; 72% GLA), DHA oil (DHAO; 73% DHA) were fed to adult wistar rats (1 mL\\/rat\\/day) starting one

Javad Nasrollahzadeh; Fereydoun Siassi; Mahmood Doosti; Mohammad Reza Eshraghian; Fazel Shokri; Mohammad Hossein Modarressi; Javad Mohammadi-Asl; Khosro Abdi; Arash Nikmanesh; Seyed Morteza Karimian

2008-01-01

382

Lipid and fatty acid composition of parasitic caligid copepods belonging to the genus Lepeophtheirus.  

PubMed

Sea lice are copepod ectoparasites that constitute a major barrier to the sustainability and economic viability of marine finfish aquaculture operations worldwide. In particular, the salmon louse, Lepeophtheirus salmonis, poses a considerable problem for salmoniculture in the northern hemisphere. The free-swimming nauplii and infective copepodids of L. salmonis are lecithotrophic, subsisting principally on maternally-derived lipid reserves. However, the lipids and fatty acids of sea lice have been sparsely studied and therefore the present project aimed to investigate the lipid and fatty acid composition of sea lice of the genus Lepeophtheirus obtained from a variety of fish hosts. Total lipid was extracted from eggs and adult female L. salmonis obtained from both wild and farmed Atlantic salmon (Salmo salar L.) sampled at two time points, in the mid 1990s and in 2009. In addition, L. salmonis from wild sea trout (Salmo trutta L.) and L. hippoglossi from wild Atlantic halibut (Hippoglossus hippoglossus L.) were sampled and analyzed. The lipids of both females and egg strings of Lepeophtheirus were characterized by triacylglycerol (TAG) as the major neutral (storage) lipid with phosphatidylcholine and phosphatidylethanolamine as the major polar (membrane) lipids. The major fatty acids were 22:6n-3 (DHA), 18:1n-9 and 16:0, with lesser amounts of 20:5n-3, 22:5n-3 and 18:0. L. salmonis sourced from farmed salmon was characterized by higher levels of 18:2n-6 and 18:3n-3 than lice from wild salmon. Egg strings had higher levels of TAG and lower DHA compared to females, whereas L. hippoglossi had lower levels of TAG and higher DHA than L. salmonis. The results demonstrate that the fatty acid compositions of lice obtained from wild and farmed salmon differ and that changes to the lipid and fatty acid composition of feeds for farmed salmon influence the louse compositions. PMID:20206710

Tocher, J A; Dick, J R; Bron, J E; Shinn, A P; Tocher, D R

2010-06-01

383

Fatty acid composition analyses of the DCMU resistant mutants of Nannochloropsis oculata (eustigmatophyceae)  

NASA Astrophysics Data System (ADS)

Ultraviolet mutagenesis was applied to Nannochloropsis oculata and three mutants resistant to 3-(3, 4-dichlorophenyl)-1,1-dimethylurea (DCMU) were isolated. The cellular chlorophyll a and total lipid content of the wild are higher in the medium supplemented with DCMU than in the control without DCMU. Without DCMU, the growth rates and chlorophyll a contents of the mutants are similar to those of the wild. Significant changes of fatty acid content and composition have occurred in DCMU-resistant mutants growing in the medium supplemented with DCMU. The total lipid, palmitic acid (16:0), palmitoleic acid (16:1?9) and oleic (18:1?9) contents decrease significantly, while the vaccenic acid (18:1?11) increases significantly and the EPA content of dried powder increases slightly in the mutants. The study may provide a basis to improve EPA content in Nannochloropsis oculata in the future.

Jimin, Zhang; Shuang, Liu; Xue, Sun; Guanpin, Yang; Xuecheng, Zhang; Zhenhui, Gao

2003-04-01

384

A novel basalt fiber-reinforced polylactic acid composite for hard tissue repair.  

PubMed

A basalt fiber (BF) was, for the first time, introduced into a poly(l-lactic acid) (PLLA) matrix as innovative reinforcement to fabricate composite materials for hard tissue repair. Firstly, BF/PLLA composites and pure PLLA were produced by the methods of solution blending and freeze drying. The results showed that basalt fibers can be uniformly dispersed in the PLLA matrix and significantly improve the mechanical properties and hydrophilicity of the PLLA matrix. The presence of basalt fibers may retard the polymer degradation rate and neutralize the acid degradation from PLLA. Osteoblasts were cultured in vitro to evaluate the cytocompatibility of the composite. An MTT assay revealed that osteoblasts proliferated well for 7 days and there was little difference found in their viability on both PLLA and BF/PLLA films, which was consistent with the alkaline phosphatase (ALP) activity results. A fluorescent staining observation showed that osteoblasts grew well on the composites. SEM images displayed that osteoblasts tended to grow along the fiber axis. The formation of mineralized nodules was observed on the films by Alizarin red S staining. These results suggest that the presence of basalt fibers does not noticeably affect osteoblastic behavior and the designed composites are osteoblast compatible. It is concluded that basalt fibers, as reinforcing fibers, may have promising applications in hard tissue repair. PMID:20683132

Chen, Xi; Li, Yan; Gu, Ning

2010-08-01

385

Prediction protein structural classes with pseudo-amino acid composition: approximate entropy and hydrophobicity pattern.  

PubMed

Compared with the conventional amino acid (AA) composition, the pseudo-amino acid (PseAA) composition as originally introduced for protein subcellular location prediction can incorporate much more information of a protein sequence, so as to remarkably enhance the power of using a discrete model to predict various attributes of a protein. In this study, based on the concept of PseAA composition, the approximate entropy and hydrophobicity pattern of a protein sequence are used to characterize the PseAA components. Also, the immune genetic algorithm (IGA) is applied to search the optimal weight factors in generating the PseAA composition. Thus, for a given protein sequence sample, a 27-D (dimensional) PseAA composition is generated as its descriptor. The fuzzy K nearest neighbors (FKNN) classifier is adopted as the prediction engine. The results thus obtained in predicting protein structural classification are quite encouraging, indicating that the current approach may also be used to improve the prediction quality of other protein attributes, or at least can play a complimentary role to the existing methods in the relevant areas. Our algorithm is written in Matlab that is available by contacting the corresponding author. PMID:17959199

Zhang, Tong-Liang; Ding, Yong-Sheng; Chou, Kuo-Chen

2008-01-01

386

Molecular dynamics simulations of trans- and cis- N-acetyl- N'-methylamides of Xaa?Pro dipeptides  

NASA Astrophysics Data System (ADS)

The occurrence of cis imide bonds in proteins is much higher than that of cis amide bonds due to the unique properties of proline. In order to examine the relationship between the high occurrence of these cis imide bonds and the residues preceding the proline, we perform molecular dynamics simulations of trans- and cis- N-acetyl- N'-methylamides of Xaa?Pro dipeptides (Ac?Xaa?Pro?NHMe). We investigate the conformational energies and structures of trans- and cis-Ac?Xaa? where Xaa has 12 amino acids in the vacuum state and 5 amino acids in the solution state. It is found that the occurrence of the cis imide bonds is strongly affected by the residue preceding the proline, and the dihedral angles (?,?) of the backbone in Ac?Xaa?Pro?NHMe are influenced by the configuration of the imide bond. We also find that the equilibrium properties of Xaa?Pro in solution simulations are more similar to the statistics of X-ray crystallographic data than are those in vacuum simulations and solvation causes a remarkable change in the conformation of the pyrrolidine ring from the endo to the exo form.

Hoon Choi, Seung; Yun Yu, Jeong; Kwang Shin, Jae; Shik Jhon, Mu

1994-07-01

387

GC constituents and relative codon expressed amino acid composition in cyanobacterial phycobiliproteins.  

PubMed

The genomic as well as structural relationship of phycobiliproteins (PBPs) in different cyanobacterial species are determined by nucleotides as well as amino acid composition. The genomic GC constituents influence the amino acid variability and codon usage of particular subunit of PBPs. We have analyzed 11 cyanobacterial species to explore the variation of amino acids and causal relationship between GC constituents and codon usage. The study at the first, second and third levels of GC content showed relatively more amino acid variability on the levels of G3+C3 position in comparison to the first and second positions. The amino acid encoded GC rich level including G rich and C rich or both correlate the codon variability and amino acid availability. The fluctuation in amino acids such as Arg, Ala, His, Asp, Gly, Leu and Glu in ? and ? subunits was observed at G1C1 position; however, fluctuation in other amino acids such as Ser, Thr, Cys and Trp was observed at G2C2 position. The coding selection pressure of amino acids such as Ala, Thr, Tyr, Asp, Gly, Ile, Leu, Asn, and Ser in ? and ? subunits of PBPs was more elaborated at G3C3 position. In this study, we observed that each subunit of PBPs is codon specific for particular amino acid. These results suggest that genomic constraint linked with GC constituents selects the codon for particular amino acids and furthermore, the codon level study may be a novel approach to explore many problems associated with genomics and proteomics of cyanobacteria. PMID:24933001

Kannaujiya, Vinod K; Rastogi, Rajesh P; Sinha, Rajeshwar P

2014-08-10

388

Exploring the Phe-Gly dipeptide-derived piperazinone scaffold in the search for antagonists of the thrombin receptor PAR1.  

PubMed

A series of Phe-Gly dipeptide-derived piperazinones containing an aromatic urea moiety and a basic amino acid has been synthesized and evaluated as inhibitors of human platelet aggregation induced by the PAR1 agonist SFLLRN and as cytotoxic agents in human cancer cells. The synthetic strategy involves coupling of a protected basic amino acid benzyl amide to 1,2- and 1,2,4-substituted-piperazinone derivatives, through a carbonylmethyl group at the N1-position, followed by formation of an aromatic urea at the exocyclic moiety linked at the C2 position of the piperazine ring and removal of protecting groups. None of the compounds showed activity in the biological evaluation. PMID:24743938

Valdivielso, Ángel M; García-López, M Teresa; Gutiérrez-Rodríguez, Marta; Herranz, Rosario

2014-01-01

389

Fatty acid composition of lipids in pot marigold (Calendula officinalis L.) seed genotypes  

PubMed Central

Background Calendula officinalis L. (pot marigold) is an annual aromatic herb with yellow or golden-orange flowers, native to the Mediterranean climate areas. Their seeds contain significant amounts of oil (around 20%), of which about 60% is calendic acid. For these reasons, in Europe concentrated research efforts have been directed towards the development of pot marigold as an oilseed crop for industrial purposes. Results The oil content and fatty acid composition of major lipid fractions in seeds from eleven genotypes of pot marigold (Calendula officinalis L.) were determined. The lipid content of seeds varied between 13.6 and 21.7 g oil/100 g seeds. The calendic and linoleic acids were the two dominant fatty acids in total lipid (51.4 to 57.6% and 28.5 to 31.9%) and triacylglycerol (45.7 to 54.7% and 22.6 to 29.2%) fractions. Polar lipids were also characterised by higher unsaturation ratios (with the PUFAs content between 60.4 and 66.4%), while saturates (consisted mainly of palmitic and very long-chain saturated fatty acids) were found in higher amounts in sterol esters (ranging between 49.3 and 55.7% of total fatty acids). Conclusions All the pot marigold seed oils investigated contain high levels of calendic acid (more than 50% of total fatty acids), making them favorable for industrial use. The compositional differences between the genotypes should be considered when breeding and exploiting the pot marigold seeds for nutraceutical and pharmacological purposes.

2013-01-01

390

Diets rich in eicosapentaenoic acid and ?-linolenic acid affect phospholipid fatty acid composition and production of prostaglandins E 1, E 2 and E 3 in turbot ( Scophthalmus maximus), a species deficient in ?5 fatty acid desaturase  

Microsoft Academic Search

Duplicate groups of juvenile turbot, (Scophthalmus maximus), were fed diets containing either Marinol K (MO), a marine fish oil rich in eicosapentaenoic acid (EPA; 20:5, n-3) or borage oil (BO), rich in ?-linolenic acid (GLA; 18:3, n-6), for a period of 12 weeks. Individual phospholipid fatty acid compositions from hearts of fish fed BO had significantly more 18:2, n-6, GLA,

J. G. Bell; D. R. Tocher; F. M. MacDonald; J. R. Sargent

1995-01-01

391

Changes in membrane fatty acid composition of Pseudomonas aeruginosa in response to UV-C radiations.  

PubMed

The changes in lipid composition enable the micro-organisms to maintain membrane functions in the face of environmental fluctuations. The relationship between membrane fatty acid composition and UV-C stress was determined for mid-exponential phase and stationary phase Pseudomonas aeruginosa. The total lipids were obtained by dichloromethane/methanol (3:1) and were quantified by GC. The TLC analysis of phospholipids showed the presence of three major fractions phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin. Significant modifications, as manifested by an increase of UFA, were obtained. Interestingly, this microorganism showed a remarkable capacity for recovery from the stressful effects of UV-C. PMID:23463516

Ghorbal, Salma Kloula Ben; Chatti, Abdelwaheb; Sethom, Mohamed Marwan; Maalej, Lobna; Mihoub, Mouadh; Kefacha, Sana; Feki, Moncef; Landoulsi, Ahmed; Hassen, Abdennaceur

2013-07-01

392

Fouling of reverse osmosis and nanofiltration membranes by humic acid—Effects of solution composition and hydrodynamic conditions  

Microsoft Academic Search

Fouling of reverse osmosis (RO) and nanofiltration (NF) membranes by humic acid, a recalcitrant natural organic matter (NOM), was systematically investigated. The membrane flux performance depended on both hydrodynamic conditions (flux and cross-flow velocity) and solution composition (humic acid concentration, pH, ionic strength, and calcium concentration), and was largely independent of virgin membrane properties. While increasing humic acid concentration and

Chuyang Y. Tang; Young-Nam Kwon; James O. Leckie

2007-01-01

393

Adrenic acid delta4 desaturation and fatty acid composition in the liver of marine-oil fed streptozotocin diabetic rats.  

PubMed

The aim of the present study was to assess the effect of streptozotocin diabetes and insulin treatment on adrenic acid delta4 desaturation and fatty acid composition of liver microsomes in Wistar rats fed a fat free semi-synthetic basal diet supplemented with 10% EPA-rich marine oil. Results showed that, in liver microsomes of hyperglycemic rats, the 22:6n-3/22:5n-3 ratio in total lipids was elevated and desaturation of adrenic acid to n-6 docosapentaenoic acid was enhanced. Insulin treatment with 2.0 I.U./100 g body weight-1 twice a day for 3 days resulted in hypoglycemia and suppressed both the increased delta4 n-6 desaturation and 22:6n-3/22:5n-3 ratio. It is concluded that the delta4 desaturation enzyme system, which is activated by experimental diabetes, is regulated by mechanisms different from those regulating delta6 and delta5 desaturations. PMID:9431819

Chanussot, B; Asdrubal, P; Huang, Y S; Poisson, J P

1997-12-01

394

Lipid and fatty acid compositions of cod ( Gadus morhua), haddock ( Melanogrammus aeglefinus) and halibut ( Hippoglossus hippoglossus)  

NASA Astrophysics Data System (ADS)

This study was conducted to compare lipid and fatty acid composition of cod, haddock and halibut. Three groups of cod (276 g ± 61 g), haddock (538 g ± 83 g) and halibut (3704 g ± 221 g) were maintained with commercial feeds mainly based on fish meal and marine fish oil for 12 weeks prior to sampling. The fatty acid compositions of muscle and liver were determined by GC/FID after derivatization of extracted lipids into fatty acid methyl esters (FAME). Lipids were also fractionated into neutral and polar lipids using Waters silica Sep-Pak?. The phospholipid fraction was further separated by high-performance thin-layer chromatography (HPTLC) and the FAME profile was obtained. Results of the present study showed that cod and haddock were lean fish and their total muscle lipid contents were 0.8% and 0.7%, respectively, with phospholipid constituting 83.6% and 87.5% of the total muscle lipid, respectively. Halibut was a medium-fat fish and its muscle lipid content was 8%, with 84% of the total muscle lipid being neutral lipid. Total liver lipid contents of cod, haddock and halibut were 36.9%, 67.2% and 30.7%, respectively, of which the neutral lipids accounted for the major fraction (88.1%-97.1%). Polyunsaturated fatty acids were the most abundant in cod and haddock muscle neutral lipid. Monounsaturated fatty acid level was the highest in halibut muscle neutral lipid. Fatty acid compositions of phospholipid were relatively constant. In summary, the liver of cod and haddock as lean fish was the main lipid reserve organ, and structural phospholipid is the major lipid form in flesh. However, as a medium-fat fish, halibut stored lipid in both their liver and muscle.

Zeng, Duan; Mai, Kangsen; Ai, Qinghui; Milley, Joyce E.; Lall, Santosh P.

2010-12-01

395

The effect of dietary docosahexaenoic acid on plasma lipoproteins and tissue fatty acid composition in humans  

Microsoft Academic Search

Normal, healthy male volunteers (n=6) were fed diets [high docosahexaenoic acid-DHA] containing 6 g\\/d of DHA for 90 d. The stabilization (low-DHA) diet contained\\u000a less than 50 mg\\/d of DHA. A control group (n=4) remained on the low-DHA diet for the duration of the study (120 d). Blood samples were drawn on study days 30 (end of\\u000a the stabilization period),

G. J. Nelson; P. C. Schmidt; G. L. Bartolini; D. S. Kelley; David Kyle

1997-01-01

396

Studies on the structure of sphingomyelinase. Amino acid composition and heterogeneity on isoelectric focusing.  

PubMed Central

Sphingomyelinase, purified to apparent homogeneity from human placenta, is an acidic protein, as judged from its amino acid composition and by isoelectric focusing of the carboxymethylated protein. The amino acid composition is characterized by an approximately equal content of hydrophobic and polar amino acid residues. The reduced-alkylated polypeptides were separated into two groups. Most of the polypeptides were heterogeneous with pI values of 4.4-5.0, but an additional more minor component was observed at pI 5.4. Liquid isoelectric focusing resolved the purified enzyme into a single major component (pI 4.7-4.8), a minor component (pI 5.0-5.4) and a plateau region of activity (pI 6-7). On thin-layer isoelectric focusing, the protein profile obtained from each of these regions was the same. In addition, the substrate specificity, Km values and effect of inhibitory substances were identical. We conclude that sphingomyelinase is an acidic, microheterogeneous protein that likely exists as a holopolymer of a single major polypeptide chain. the heterogeneity of the intact protein on isoelectric focusing appears to reflect this microheterogeneity, which is influenced by a tendency to associate with itself and with detergents such as Triton X-100. Images Fig. 1. Fig. 2. Fig. 4.

Jones, C S; Shankaran, P; Davidson, D J; Poulos, A; Callahan, J W

1983-01-01

397

A Preliminary Study of 13C-Phenylalanine and 13C-Dipeptide Breath Tests in Horses  

PubMed Central

This study aimed to establish a standard dose and sample collection time for 13C phenylalanine and 13C-Dipeptide breath test in horses. To evaluate dose-dependent effects, healthy horses received 2.5 mg/kg, 5 mg/kg, and 10 mg/kg 13C phenylalanine dissolved in 1 ml/kg distilled water and 1.25 mg/kg, 2.5 mg/kg, and 5 mg/kg 13C dipeptide dissolved in 2 ml/ kg distilled water. Tmax was observed during the sample collection time. For 13C phenylalanine, the standard deviation of Cmax at 5 mg/kg was lower than that of 10 mg/kg. For 13C dipeptide, the standard deviation of Tmax was the lowest at 5 mg/kg. This study revealed that an optimal dose for breath tests with 13C phenylalanine and 13C dipeptide may be 5 mg/kg in horses.

SASAKI, Naoki; TSUZUKI, Nao; YAMADA, Michiaki; MINAMI, Takuto; YAMADA, Haruo

2009-01-01

398

Annulated Diketopiperazines from Dipeptides or Sch?llkopf Reagents via Tandem Cyclization-Intramolecular N-Arylation  

PubMed Central

Facile CuI-mediated N-arylation of diketopiperazine using the Fukuyama modification of the Ullmann-Goldberg reaction can be exploited in new approaches to enantio-pure polycyclic diketopiperazines from easily assembled dipeptides or functionalized Schöllkopf reagents.

Lim, Hwan Jung; Gallucci, Judith C.; RajanBabu, T. V.

2010-01-01

399

Lipid and fatty acid composition of brush border membrane of rat intestine during starvation  

Microsoft Academic Search

Alterations in the lipid and fatty acid composition of brush border membrane (BBM) of small intestine were studied in well-fed,\\u000a starved, and refed rats. The ratios of cholesterol\\/phospholipid (mol\\/mol), sphingomyelin\\/phosphatidylcholine (mol\\/mol), protein\\/lipid\\u000a (w\\/w), and free fatty acids (w\\/w) decreased whereas the total phospholipid (w\\/w) ratio and the double-bond index increased\\u000a in BBM of the intestine of the starved rat compared

A. A. Waheed; F. Yasuzumi; P. D. Gupta

1998-01-01

400

Fatty acid, triglyceride and tocopherol composition of Algerian Argan ( Argania spinosa ) fruit seed lipids  

Microsoft Academic Search

The main focus of the present work is the analytical study of the fatty acid, triglyceride (TAG) and tocopherol composition\\u000a of oil extract from the fruit of Algerian tree Argania spinosa. The four dominant fatty acids (FA) found in the oil are: oleic C18:1 (52.86%), linoleic C18:2 (25.0%), palmitic C16:0 (14.65%)\\u000a and stearic C18:0 (7.06%). The distribution of FA between

Mohamed Yousfi; Isabelle Bombarda; Chahrazed Hamia; Amar Djeridane; Pierre Stocker; Emile Gaydou

2009-01-01

401

Recent developments in altering the fatty acid composition of ruminant-derived foods.  

PubMed

There is increasing evidence to indicate that nutrition is an important factor involved in the onset and development of several chronic human diseases including cancer, cardiovascular disease (CVD), type II diabetes and obesity. Clinical studies implicate excessive consumption of medium-chain saturated fatty acids (SFA) and trans-fatty acids (TFA) as risk factors for CVD, and in the aetiology of other chronic conditions. Ruminant-derived foods are significant sources of medium-chain SFA and TFA in the human diet, but also provide high-quality protein, essential micronutrients and several bioactive lipids. Altering the fatty acid composition of ruminant-derived foods offers the opportunity to align the consumption of fatty acids in human populations with public health policies without the need for substantial changes in eating habits. Replacing conserved forages with fresh grass or dietary plant oil and oilseed supplements can be used to lower medium-chain and total SFA content and increase cis-9 18:1, total conjugated linoleic acid (CLA), n-3 and n-6 polyunsaturated fatty acids (PUFA) to a variable extent in ruminant milk. However, inclusion of fish oil or marine algae in the ruminant diet results in marginal enrichment of 20- or 22-carbon PUFA in milk. Studies in growing ruminants have confirmed that the same nutritional strategies improve the balance of n-6/n-3 PUFA, and increase CLA and long-chain n-3 PUFA in ruminant meat, but the potential to lower medium-chain and total SFA is limited. Attempts to alter meat and milk fatty acid composition through changes in the diet fed to ruminants are often accompanied by several-fold increases in TFA concentrations. In extreme cases, the distribution of trans 18:1 and 18:2 isomers in ruminant foods may resemble that of partially hydrogenated plant oils. Changes in milk fat or muscle lipid composition in response to diet are now known to be accompanied by tissue-specific alterations in the expression of one or more lipogenic genes. Breed influences both milk and muscle fat content, although recent studies have confirmed the occurrence of genetic variability in transcript abundance and activity of enzymes involved in lipid synthesis and identified polymorphisms for several key lipogenic genes in lactating and growing cattle. Although nutrition is the major factor influencing the fatty acid composition of ruminant-derived foods, further progress can be expected through the use of genomic or marker-assisted selection to increase the frequency of favourable genotypes and the formulation of diets to exploit this genetic potential. PMID:23031638

Shingfield, K J; Bonnet, M; Scollan, N D

2013-03-01

402

Phospholipid Analyses for Microbial Community Composition in Alpine Acid Rock Drainage  

NASA Astrophysics Data System (ADS)

This project is examining factors of non-anthropogenic acid rock drainage that influence microbial community composition in the Peekaboo Gulch drainage basin (Sawatch Range, Colorado). At this site, natural acid rock drainage outflows from acidic springs (pH=2.6) on Red Mountain. The acid drainage converges with South Fork Lake Creek (pH ~ 7.0, prior to convergence) two miles down gradient. Sediment samples were collected across confluences with gradient of pH, temperature, conductivity and metal concentration. In-situ parameter measurements ranged from 2.3 to 7.9 of pH, 3.8 to 16.6 degree Celsius for temperature, and 34.9 to 1820 for conductivity. Biomass as measured by phospholipids ranged from 280 to 95,900 pmol/g sediment. The only relationship between the in situ parameters and the phospholipid profiles is a weak positive correlation between pH and branched monounsaturated fatty acid methyl esters in that at a pH greater than 5.0 these fatty acid methyl esters were detected. The phospholipid profiles were diverse across the samples. These profiles changed with respect to the spatial relationship within the drainage pattern. The highest alpine samples contained greater relative abundances of monounsaturated fatty acid methyl esters compared to the lower alpine samples. Microbial community profiles shifted at each confluence depending on water source chemistry. Continuing research is needed to determine other biogeochemical factors that may influence these community shifts.

Webster, C. E.; Tapp, J. B.; Pfiffner, S. M.

2008-12-01

403

Influence of Aerosol Acidity on the Chemical Composition of Secondary Organic Aerosol from ?-caryophyllene  

NASA Astrophysics Data System (ADS)

The secondary organic aerosol (SOA) yield of ?-caryophyllene photooxidation is enhanced by aerosol acidity. In the present study, the influence of aerosol acidity on the chemical composition of ?-caryophyllene SOA is investigated using ultra performance liquid chromatography/electrospray ionization-time-of-flight mass spectrometry (UPLC/ESI- TOFMS). A number of first- , second- and higher-generation gas-phase products having carbonyl and carboxylic acid functional groups are detected in the particle phase. Particle-phase reaction products formed via hydration and organosulfate formation processes are also detected. Increased acidity leads to different effects on the abundance of individual products; significantly, abundances of organosulfates are correlated with aerosol acidity. The increase of certain particle-phase reaction products with increased acidity provides chemical evidence to support the acid-enhanced SOA yields. Based on the agreement between the chromatographic retention times and accurate mass measurements of chamber and field samples, three ?-caryophyllene products (i.e., ?-nocaryophyllon aldehyde, ?-hydroxynocaryophyllon aldehyde, and ?-dihydroxynocaryophyllon aldehyde) are suggested as chemical tracers for ?-caryophyllene SOA. These compounds are detected in both day and night ambient samples collected in downtown Atlanta, GA and rural Yorkville, GA during the 2008 August Mini-Intensive Gas and Aerosol Study (AMIGAS).

Chan, M.; Surratt, J. D.; Chan, A. W.; Schlling, K.; Offenberg, J. H.; Lewandowski, M.; Edney, E.; Kleindienst, T. E.; Jaoui, M.; Edgerton, E. S.; Tanner, R. L.; Shaw, S. L.; Zheng, M.; Knipping, E. M.; Seinfeld, J.

2011-12-01

404

Influence of aerosol acidity on the chemical composition of secondary organic aerosol from ?-caryophyllene  

NASA Astrophysics Data System (ADS)

The secondary organic aerosol (SOA) yield of ?-caryophyllene photooxidation is enhanced by aerosol acidity. In the present study, the influence of aerosol acidity on the chemical composition of ?-caryophyllene SOA is investigated using ultra performance liquid chromatography/electrospray ionization-time-of-flight mass spectrometry (UPLC/ESI-TOFMS). A number of first-, second- and higher-generation gas-phase products having carbonyl and carboxylic acid functional groups are detected in the particle phase. Particle-phase reaction products formed via hydration and organosulfate formation processes are also detected. Increased acidity leads to different effects on the abundance of individual products; significantly, abundances of organosulfates are correlated with aerosol acidity. To our knowledge, this is the first detection of organosulfates and nitrated organosulfates derived from a sesquiterpene. The increase of certain particle-phase reaction products with increased acidity provides chemical evidence to support the acid-enhanced SOA yields. Based on the agreement between the chromatographic retention times and accurate mass measurements of chamber and field samples, three ?-caryophyllene products (i.e., ?-nocaryophyllon aldehyde, ?-hydroxynocaryophyllon aldehyde, and ?-dihydroxynocaryophyllon aldehyde) are suggested as chemical tracers for ?-caryophyllene SOA. These compounds are detected in both day and night ambient samples collected in downtown Atlanta, GA and rural Yorkville, GA during the 2008 August Mini-Intensive Gas and Aerosol Study (AMIGAS).

Chan, M. N.; Surratt, J. D.; Chan, A. W. H.; Schilling, K.; Offenberg, J. H.; Lewandowski, M.; Edney, E. O.; Kleindienst, T. E.; Jaoui, M.; Edgerton, E. S.; Tanner, R. L.; Shaw, S. L.; Zheng, M.; Knipping, E. M.; Seinfeld, J. H.

2011-02-01

405

Influence of aerosol acidity on the chemical composition of Secondary Organic Aerosol from ?-caryophyllene  

NASA Astrophysics Data System (ADS)

The secondary organic aerosol (SOA) yield of ?-caryophyllene photooxidation is enhanced by aerosol acidity. In the present study, the influence of aerosol acidity on the chemical composition of ?-caryophyllene SOA is investigated using ultra performance liquid chromatography/electrospray ionization-time-of-flight mass spectrometry (UPLC/ESI-TOFMS). A number of first-, second- and higher-generation gas-phase products having carbonyl and carboxylic acid functional groups are detected in the particle phase. Particle-phase reaction products formed via hydration and organosulfate formation processes are also detected. Increase of acidity leads to different effects on the abundance of individual products; significantly, abundances of organosulfates are correlated with aerosol acidity. To our knowledge, this is the first detection of organosulfates and nitrated organosulfates derived from a sesquiterpene. The increase of certain particle-phase reaction products with increased acidity provides chemical evidence to support the acid-enhanced SOA yields. Based on the agreement between the chromatographic retention times and accurate mass measurements of chamber and field samples, three ?-caryophyllene products (i.e., ?-nocaryophyllon aldehyde, ?-hydroxynocaryophyllon aldehyde, and ?-dihydroxynocaryophyllon aldehyde) are identified as chemical tracers for ?-caryophyllene SOA. These compounds are detected in both day and night ambient samples collected in downtown Atlanta, GA and rural Yorkville, GA during the 2008 August Mini-Intensive Gas and Aerosol Study (AMIGAS).

Chan, M. N.; Surratt, J. D.; Chan, A. W. H.; Schilling, K.; Offenberg, J. H.; Lewandowski, M.; Edney, E. O.; Kleindienst, T. E.; Jaoui, M.; Edgerton, E. S.; Tanner, R. L.; Shaw, S. L.; Zheng, M.; Knipping, E. M.; Seinfeld, J. H.

2010-11-01

406

Whole-genome association study of fatty acid composition in a diverse range of beef cattle breeds.  

PubMed

Fatty acid composition of adipose tissue associated with meat is an important factor for the beef industry because of its implications for human health, processing, meat quality, and palatability. Individual fatty acid composition is a trait under genetic control, so improvement via selective breeding of cattle is possible. The objective of this study was to investigate the genetic architecture of fatty acid composition and identify genes associated with this trait in 3 breed types: Bos indicus (Brahman), Bos taurus (4 breeds), and tropically adapted composites (2 breeds). Using high-density data, regions on chromosomes 1, 9, 14, 16, 19, 23, 26, 29, and X were associated with fat composition and quantity traits. Known candidate genes, such as fatty acid synthase (FASN; chromosome 19) and stearoyl-CoA desaturase (SCD; chromosome 26), were confirmed in our results. Other candidate genes and regions represent novel association results, requiring further validation. PMID:24782392

Kelly, M J; Tume, R K; Fortes, M; Thompson, J M

2014-05-01

407

Capsid Polypeptides of Mouse Elberfeld Virus I. Amino Acid Compositions and Molar Ratios in the Virion  

PubMed Central

The four major polypeptide chains (alpha, beta, gamma, delta) constituting the capsid protein of mouse Elberfeld (ME) virus were isolated by preparative electrophoresis on polyacrylamide gels, and the amino acid composition of each chain was determined. In addition, the molecular weights of the smallest chains of ME virus, mengovirus, and poliovirus, which had previously been determined by gel electrophoretic methods, were redetermined by gel filtration chromatography in 6 m guanidine hydrochloride. Each was found to have a molecular weight about 7,300. Using the reevaluated molecular weights and the known amino acid compositions of the chains, the molar ratio of each chain in the ME virion was determined by quantitative analysis of the distribution of radioactivity in the electrophoretically separated chains of virus which had been specifically radiolabeled with leucine or with methionine. Equimolar proportions of all four chains were found in the virion.

Stoltzfus, C. Martin; Rueckert, Roland

1972-01-01

408

Melamine/Stearic Acid Composite Nanowires and Vesicles with an Intercalated Nanostructure Prepared through NCCM Method  

NASA Astrophysics Data System (ADS)

A solvent-non-solvent method invented in our laboratory for preparing non-covalently connected micelles (NCCM) was used to intercalate melamine (MA) molecules into stearic acid (SA) bilayers to form the composite nanoparticles with an intercalated nanostructure in which a melamine bilayer is sandwiched between two stearic acid bilayers, NCCM method helps to sufficiently mix the two components in nanospace and meanwhile inhibits the strong tendency of self-crystallization of MA, leading to the intercalation. Although the nanoparticles have a regular inner structure, the primary MA/SA nanoparticles have an irregular morphology. Regular nanoparticles were obtained through annealing the suspension of the primary nanoparticles. Through annealing at different temperatures, the MA/SA composite nanowires and vesicles with an intercalated structure were prepared respectively. It is proposed that the morphological change results from the change in the intercalated structure.

Guo, Juan; Chen, Dao-yong

2012-12-01

409

Using casein and oxidized hyaluronic acid to form biocompatible composite hydrogels for controlled drug release.  

PubMed

To develop biocompatible polymeric hydrogels for the in-situ encapsulation and controlled release of hydrophilic drugs, the oxidized hyaluronic acid containing aldehyde groups was prepared by the reaction between hyaluronic acid and sodium periodate, and then used for the first time to crosslink casein protein in aqueous system. By changing its aldehyde group content or amount, we found that the gelation kinetics and the properties of resultant composite hydrogel could be modulated. Particularly, an increase of its aldehyde group content or amount was found to result in a shorten gelation time, an enhanced gel strength, a reduced swelling ratio and a prolonged drug release. In addition, the as obtained composite hydrogel was also evaluated for its in vitro cytotoxicity on L929 mouse fibroblast cells and was confirmed to have a good biocompatibility. PMID:24433914

Li, Nan-Nan; Fu, Chao-Ping; Zhang, Li-Ming

2014-03-01

410

Lactic acid/wood-based composite material. Part 1: Synthesis and characterization.  

PubMed

As biomass feedstock, wood and lactic acid biopolymers have been used as constituents of an innovative biocomposite material possessing remarkable properties. Three different systems were made by soaking lactic acid oligomers into solid wood and then oven heating to induce in situ polymerisation, confirmed by Fourier transformed infrared spectroscopy (FTIR) and gel permeation chromatography (GPC) analysis. Combinations of treatment systems and heating durations, implying structural wood modification, led to different physical behaviours of the composites. The first obtained material was in the form of softened and easily bendable wood. Subjected to an extended heating period, this softened material could then regain its initial hardness. Another treatment parameter combination directly led to densified wood with improved properties. These two main composite materials are expected to be useable for bending, stamping or flooring industrial uses, depending on their physical condition. PMID:19473836

Noël, Marion; Fredon, Emmanuel; Mougel, Eric; Masson, Daniel; Masson, Eric; Delmotte, Luc

2009-10-01

411

Solvation structure, thermodynamics, and conformational dependence of alanine dipeptide in aqueous solution analyzed with reference interaction site model theory  

Microsoft Academic Search

With the CHARMM22 (Chemistry at Harvard Macromolecular Mechanics) all-atom nonbonded potential parameters for alanine dipeptide solute and the transferable intermolecular potential model water for the solvent, the reference interaction site model (RISM) integral equations with the hypernetted chain closure are solved to obtain all the atomic solvent-solute radial distribution functions. The solvation structures of alanine dipeptide in its seven conformations:

Qizhi Cui; Vedene H. Smith

2003-01-01

412

Effects of chlorinated benzenes on diatom fatty acid composition and quantitative morphology. III. 1,2,3-Trichlorobenzene.  

PubMed

Cells of the diatom Cyclotella meneghiniana were exposed in a closed system to 0.245 ppm 1,2,3-trichlorobenzene. Response of the diatom was measured by quantitative ultrastructure and fatty acid percent composition over a 5-day period. During that time, 35 significant morphological and 12 fatty acid percent composition changes occurred. The most pronounced morphological change that occurred was a significant increase in lipid volume. In addition, changes were observed in vacuolar relative volume, suggesting that the tonoplast became more permeable. Fewer significant changes were observed in fatty acid percent composition upon exposure to this isomer. However, there was a consistent increase in oleic acid (C18:1). The observed changes in morphological and fatty acid percent composition were uniformly distributed with time after the first hour of exposure. Results support the hypothesis that increased lipid stores may alter the timing of response to lipophilic toxicants. PMID:2802669

Sicko-Goad, L; Hall, J; Lazinsky, D; Simmons, M S

1989-09-01

413

Milk Composition and Apparent Digestibilities of Dietary Fatty Acids in Lactating Dairy Cows Abomasally Infused with Cis or Trans Fatty Acids[1], [2] and [3  

Microsoft Academic Search

Fat supplementation of diets for dairy cows produces changes in nutrient supply and milk composition. The effect of abomasal infusion of either cis-C18:1 or trans- C18:1 fatty acid isomers on the digestibility of fatty acids and milk composition was determined in lactating dairy cows. Six multiparous midlactation Holstein cows were used and fed a control diet containing 50% forage and

G. A. Romo; R. A. Erdman; B. B. Teter; J. Sampugna; D. P. Casper

2000-01-01

414

Synthesis of Some Novel Benzylidenehydantoins: Amino Acids Derivatives  

Microsoft Academic Search

5-Benzylidenehydantoin reacts with chlorosulfonic acid to give the corresponding p-sulfonyl chloride. Condensation of the latter with amino acids leads to sulfonylamino acid derivatives, which on coupling with glycine methyl ester hydrochloride in THF-Et3N using the dicyclohexylcarbodiimide method furnish the desired dipeptide methyl esters. The spectral data of the compounds are briefly discussed.

Ragab A. El-Sayed

2001-01-01

415

Investigation of PEMFC operation above 100 °C employing perfluorosulfonic acid silicon oxide composite membranes  

NASA Astrophysics Data System (ADS)

Various perfluorosulfonic acid membranes (PFSAs) were studied as pure and silicon oxide composite membranes for operation in hydrogen/oxygen proton-exchange membrane fuel cells (PEMFCs) from 80 to 140 °C. The composite membranes were prepared either by impregnation of pre-formed PFSAs via sol-gel processing of a polymeric silicon oxide, recasting a film using solubilized PFSAs and a silicon oxide polymer/gel. All composite membranes had a silicon oxide content of less than or equal to 10% by weight. Decreasing the equivalent weight and thickness of the PFSAs, in addition to the incorporation of silicon oxide helped improve water management in a PEMFC at elevated temperatures. Fourier transform-infrared spectroscopy-attenuated total reflectance (FT-IR-ATR), and scanning electron microscopy (SEM) experiments indicated an evenly distributed siloxane polymer in all of the composite membranes. At a potential of 0.4 V the Aciplex 1004/silicon oxide composite membrane in a humidified H 2/O