Wyniki wyszukiwania

1

The interaction of tryptophan and ANS with PAMAM dendrimers

100%

Klajnert B., Bryszewska M.

Cellular and Molecular Biology Letters

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2002

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tom 07

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nr 4

Dendrimers are globular, hyperbranched polymers possessing a high concentration of surface functional groups and internal cavities. These unique features make them very useful in many biomedical applications, especially as carrier molecules. In this study, the interaction of tryptophan and 1-anilinonaphthalene-8-sulfonic acid with three types of polyamidoamine dendrimers was examined. It was observed that the type of dendrimer surface group has a strong impact on the interactions between the dendrimers and fluorescent molecules.

2

The effect of immobilization in the PVA films on the fluorescence and phosphorescence lifetime of indole and its derivatives

100%

Kowalska-Baron A., Choudhary P., Montes D.

Biotechnology and Food Science

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2011

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tom 75

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nr 2

3

Optimum ratio of standardized ileal digestible tryptophan to lysine for piglets

100%

Borgesa G., Woyengo T. A., Nyachoti C. M.

Journal of Animal and Feed Sciences

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2013

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tom 22

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nr 4

Two experiments were conducted to determine optimal standardized ileal digestible (SID) tryptophan:lysine ratio for piglets using growth performance and plasma urea N as response criteria. In Experiment 1, piglets were fed 6 diets with 8.5, 9.5, 10.5, 11.5, 12.5 or 13.5 g · kg–1 SID lysine to estimate lysine requirement. In Experiment 2, piglets were fed 6 diets with 9.2 g · kg–1 SID lysine, and 0.178, 0.182, 0.196, 0.216, 0.227 or 0.236 SID trytophan:lysine to estimate optimal tryptophan:lysine ratio. The SID lysine requirement was estimated to be 10.2 g · kg–1. Response criteria measured were unaffected by SID tryptophan:lysine ratio, implying that the diets fed were not deficient in tryptophan. In conclusion, the SID lysine requirement for the piglets was close to the recommendation by NRC (1998; 10.1 g · kg–1), but not NRC (2012; 12.3 g · kg–1). The optimal SID tryptophan:lysine ratio of the piglets was either equal to or less than 0.178.

4

Spectroscopic studies of naproxen and tryptophan immobilized in polyvinyl alcohol

100%

Sabara D.M. D. M., Dunne J.S. J. S., Pedro A.Q.H. A. Q. H., Trifunovic J. J., Balogun I.I.O. I. I. O., Kotlicic O. O., Serrano A. A., Kertesz I. I.

Biotechnology and Food Science

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2011

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tom 75

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nr 1

5

Plasma kynurenic acid concentration in patients undergoing cardiac surgery: effect of anaesthesia

84%

Kotlinska-Hasiec E., Nowicka-Stazka P., Parada-Turska J., Stazka K., Stazka J., Zadora P., Dabrowski W.

Archivum Immunologiae et Therapiae Experimentalis

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2015

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tom 63

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nr 2

6

Chemical composition and amino acid profile of Sardinella longiceps collected from Western coastal areas of Kerala, India

84%

Shaji S. A., Hindumathy C. K.

Journal of Biology and Earth Sciences

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2013

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tom 03

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nr 1

7

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Secondary metabolites in the response of model Brassicaceae species to Plectosphaerella cucumerina

84%

Kulak K., Bednarek P.

BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology

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2013

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tom 94

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nr 3

8

Fatigue development mechanisms during increased intensity exertion

84%

Klich S.

Central European Journal of Sport Sciences and Medicine

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2013

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tom 01

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nr 1

During motor preparation, the attention is paid more and more frequently to the complex significance of fatigue in the case of the achieved sport outcome. The complexity of this process has not been utterly explained so far. It is important to acquire the profound knowledge about the central and peripheral fatigue while explaining this mechanism, because they remain in the background of the human body malfunction. It needs to be emphasized that both fatigue mechanisms should not be analyzed separately, because they are subordinated to one another. The changes mechanism in central nervous system (CNS) influenced by physical exertion leads to reticular formation impairment. This in turn results in analytic and decision making process malfunction. The proper functioning of these centers depends on appropriate neurotransmitters concentration. The short tryptophan to serotonin metabolic pathway plays a significant role in the central fatigue development. The concentration increase of this hormone leads to CNS malfunction, which causes the above mentioned changes. The purpose of this paper was to show, based on the current literature data, the predisposing mechanisms and factors in the development of fatigue.

9

Intramolecular electron transfer between tryptophan radical and tyrosine in oligoproline-bridged model peptides and hen egg-white lysozyme

84%

Wierzchowski K. L.

Acta Biochimica Polonica

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1997

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tom 44

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nr 4

Long range electron transfer (LRET) across protein matrix underlies all one-electron cellular redox reactions. Elucidation of molecular electron transfer pathways and parametrization of their relative efficiency is one of the most challenging problems in the studies on LRET in proteins. In this paper results of pulse radiolysis investigations on kinetics of LRET accompanying intramolecular radical transformation Trp. --> TyrO. in model peptides built of tryptophan and tyrosine bridged by an oligoproline fragment are reviewed, along with an interpretation of the observed distance dependence of the rate of LRET in terms of conformational properties of the peptides, and partitioning of LRET between electron transfer pathways through space and through peptide backbone. This review on model peptide systems is supplemented with recapitulation of similar studies on the same intramolecular transformation in hen egg-white lysozyme, which allowed to identify Trp./Tyr redox pairs and associated electron transfer pathways involved in LRET in this protein.

10

Comparison of meat quality characteristics between commercial pigs and snails

84%

Zymantiene J., Jukna V., Jukna C., Zelvyte R., Oberauskas V.

Polish Journal of Food and Nutrition Sciences

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2008

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tom 58

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nr 1

Nowadays traditional pork is still remaining the most popular meat in many European countries. In contrast, presently there is a growing interest in the production and marketing of non traditional snail meat. The aim of the present study was to compare the quality characteristics of pork and snails’ meat, to determine an impact of animal species on meat quality and to analyse the correlation coefficients of some parameters of meat quality. The meat quality characteristics, as chemical composition and some physical properties, were evaluated after deep-freezing. It was determined that snail meat contained by 11.50% higher amount of water, by 14.60% higher amount of mineral substances and by 77.04% higher amount of amino acid hydroxyproline, but by 77.38% less fat, by 37.94% less protein and by 43.28% tryptophan if to compare to the pork meat. Besides, pH in snail meat tended to be alkaline while in pork meat – acid. Moreover, snail meat was darker, pale red and its yellowness was more intensive than that of the pork meat. The correlation between fat and protein in pork and snail meat, pH with tryptophan and hydroxyproline was negative, whereas pH with fat, and dry matter with ash – positive. However, in pork meat tryptophan and hydroxyproline correlated negatively, while in snail meat – positively. Meat chemical composition and physical properties were effected by animal species.

11

Effect of cadmium on the peripheral kynurenine pathway in rats

84%

Pawlak D., Brzoska M., Moniuszko-Jakoniuk J., Stypulkowska A., Zwierz K.

Polish Journal of Environmental Studies

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2005

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tom 14

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nr 4

This study investigated the kynurenine metabolism in rats treated with cadmium. We used an animal model at the levels of Cd corresponding to human environmental and occupational exposure to this metal which allows the assessment of its early effect on the structure and function of kidneys. We observed significant decrease in the serum concentration of tryptophan (TRP) and its metabolites: kynurenine (KYN), kynurenic acid (KYNA), and 3-hydroxykynurenine (3-HKYN), which was accompanied by a decrease in KYN derivatives in kidney and liver tissues. This effect was dependent on the level of Cd exposure. Regression analysis showed negative correlations between blood concentrations of Cd and TRP derivatives in serum, kidney and liver tissues. Conversely, the urinary concentration of KYN and KYNA increased. Changes in product degradation of TRP after Cd treatment were proportional to the severity of renal damage and correlated with the concentration of proximal tubular injury marker — urinary isoenzyme B of N-acetyl-D-glucosaminidase (NAG-B). Our results seem to indicate that intoxication with Cd induced significant disturbances in the peripheral kynurenine pathway.

12

Covalent modification and site-directed mutagenesis of an active site tryptophan of human prostatic acid phosphatase

84%

Zhang Z., Ostanin K., Van Etten R. L.

Acta Biochimica Polonica

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1997

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tom 44

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nr 4

Because tryptophans are found as part of the phosphate binding sites in a number of proteins, human prostatic acid phosphatase (hPAP) was examined for the presence and the role of essential tryptophan residues. The pH dependence of the intrinsic fluorescence of hPAP resembled the kinetic pH dependence. Chemical modification by N-bromosuccinimide (NBS) resulted in an inactivation of the enzyme and produced a characteristic reduction of the protein absorbance at 280 nm. Two tryptophans per subunit were modified, and this was accompanied by an apparently complete loss of enzymatic activity. In the presence of the competitive inhibitor L-(+)-tartrate, the loss of enzyme activity was significantly reduced as compared to the rate of tryptophan modification. After labeling the protein with 2,4-dinitrophenylsulfenyl chloride (DNPS-Cl), two tryptic peptides containing DNPS-labeled tryptophans were isolated and the sequences were identified by amino acid sequence analysis and mass spectroscopy. One peptide corresponded to residues 172-176, and included Trp174. The other corresponded to the C-terminal sequence, including Trp336. It was concluded that Trp174 was at the active site of the human enzyme because it was protected by the competitive inhibitor tartrate in the DNPS-Cl modification studies. This is also consistent with the location of a homologous residue in the structure of the rat enzyme. Using site-directed mutagenesis, Trp174 was replaced by Phe or Leu. Both mutants showed altered kinetic properties, including lower Km values with several aromatic substrates, and also exhibited reduced stability towards urea denaturation.

13

Can kynurenine pathway tryptophan metabolites be used to monitor cadmium exposure?

84%

Pawlak D., Brzoska M., Zwierz K., Stypulkowska A., Moniuszko-Jakoniuk J.

Polish Journal of Environmental Studies

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2005

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tom 14

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nr 2

We evaluated the possibility of using the urinary concentrations of tryptophan metabolites such as kynurenine (KYN) and kynurenic acid (KYNA) for monitoring cadmium (Cd) exposure and detecting early effects of its action in the kidney. For this purpose, we analyzed correlations between urinary excretion of both metabolites, Cd concentration and the activity of isoenzyme B of N-acetyl-β-D-glucosaminidase (NAG-B), recognized as one of the most sensitive markers of Cd nephrotoxicity. The study was conducted on rats using an experimental model, corresponding to human environmental and occupational exposure to Cd. The rats were administered 5 and 50 mg Cd/l of drinking water for 24 weeks. The administration of Cd resulted in a marked dose-dependent increase in KYN and KYNA elimination. Regression analysis revealed a linear correlation between urinary Cd concentration and KYN or KYNA excretion as well as between urinary NAG-B activity and KYN or KYNA elimination. We hypothesize that metabolites of tryptophan via kynurenine pathway such as KYN and especially KYNA can be used to monitor chronic exposure to Cd.

14

The concentration of kynurenine in rat model of asthma

67%

Kucharewicz I., Kasacka I., Pawlak D., Tankiewicz-Kwedlo A., Mroczko B., Buczko W., Bodzenta-Lukaszyk A.

Folia Histochemica et Cytobiologica

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2008

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tom 46

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nr 2

199-203

15

Ciemnienie i moc redukcyjna roztworów aminokwasów z cukrami

67%

Markuze Z.

Roczniki Państwowego Zakładu Higieny

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1959

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tom 10

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nr 1

16

Modulation of IAA production in Cyanobacteria by tryptophan and light

67%

Prasanna R., Joshi M., Rana A., Nain L.

Polish Journal of Microbiology

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2010

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tom 59

|

nr 2

99-105

Cyanobacteria represent less a investigated group of prokaryote, in terms of their plant growth promoting potential, especially in relation to the production of phytohormones. The present investigation was aimed towards analyzing growth kinetics, indole acetic acid (IAA) production and acetylene reduction activity (ARA) as an index of nitrogen fixation in two selected cyanobacteria) strains belonging to the genus Anahaena, as influenced by tryptophan supplementation and lighkdark conditions. Interesting observations were recorded in terms of enhancement of IAA production accompanied by protein and chlorophyll accumulation in the two cyanobacterial strains grown in media without tryptophan and incubated under lightidark or continuous light conditions. Colorimetric and chromatographic analyses supported the observations that tryptophan is not essential as a precursor for IAA biosynthesis in these cyanobacteria. Further study is in progress to identify genes involved in the tryptophan independent pathway for IAA biosynthesis.

17

The valproic acid-induced effects on kynurenine pathway correlate with the changes in the central and peripheral concentration of amino acids

67%

Maciejak P., Szyndler J., Turzynska D., Sobolewska A., Kolosowska K., Lehner M., Wislowska-Stanek A., Skorzewska A., Hamed A., Plaznik A.

Acta Neurobiologiae Experimentalis

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2013

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tom 73

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nr 1

Despite its widespread use, the mechanisms of valproic acid (VPA) action are not fully understood. In the current study, we have examined the peripheral and central effects of VPA administration on the metabolic pathway of tryptophan (TRP): concentration of its centrally active metabolites, kynurenine (KYN) and kynurenic acid (KYNA). Moreover, the role of a displacement of TRP from serum albumin binding sites, and changes in the peripheral and central concentration of amino acid including glutamate (GLU), GABA, alanine (ALA), glutamine (GLTM), glycine (GLY), aspartate (ASP), were also studied. We found that VPA administration produced a progressive and strong increase in the central concentration of KYNA, KYN and TRP. Simultaneously, TRP concentration in plasma declined while the peripheral increase of KYNA in plasma was weaker and occurred earlier than in the hippocampus. We also observed that administration of ibuprofen to rats, a prototypic drug used to study drug binding to serum albumin, strongly increased the amount of a free serum and hippocampal TRP concentration, to a degree similar to the effect of VPA. Moreover, we found that the most pronounced changes in the concentration of amino acids caused by administration of VPA include an increase of GLU and a decrease of ALA in the plasma as well as a decrease of ASP and an increase of GABA in the brain. The factor analysis revealed that the changes in the concentrations of TRP, determined both in the plasma and in the hippocampus grouped strongly with the changes in the plasma concentrations of GLU and the central concentration of ASP. Our results showed that administration of VPA strongly modifies the activity of the kynurenine pathway with significant changes in TRP, KYN and KYNA levels in the CNS. The reason for this may be a strong VPA-induced displacement of TRP from its binding sites to plasma albumin. It appears also that the changes in TRP evoked by VPA administration due to competition for transport into the brain, may result in a shift in the central and peripheral balance between branched-chain (BCAA) and aromatic amino acids (AAA). This may lead to a decrease in BCAA transport to the brain, leading to a deficit of BCAAs as a donor of amino groups to the process of GLU resynthesis from pyruvate. Changes in the BCAA/ AAA ratio, arising as a consequence of changes in the TRP level, could explain an observed increase in the plasma concentrations of GLU and a decrease in the ASP concentrations in the brain that occurred after administration of VPA. In sum, given the neuroprotective role of KYNA, the current study suggests that stimulation of the kynurenine pathway may also apply to the central and peripheral concentration of amino acids. The modification of the activity of the kynurenine pathway may at least in part contribute to the related antiepileptic and neuroprotective mechanisms of VPA action.

18

Effects of treatment with melatonin and tryptophan on liver enzymes, parameters of fat metabolism and plasma levels of cytokines in patients with non-alcoholic fatty liver disease – 14 months follow up

67%

Celinski K., Konturek P. C., Slomka M., Cichoz-Lach H., Brzozowski T., Konturek S. J., Korolczuk A.

Journal of Physiology and Pharmacology

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2014

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tom 65

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nr 1

19

Stezenie tryptofanu w surowicy kobiet narazonych na przewlekle dzialanie dwusiarczku wegla

67%

Kuligowski D., Stanosz S., Kuligowska E.

Bromatologia i Chemia Toksykologiczna

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1994

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tom 27

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nr 4

343-346

U 140 kobiet, z prawidłowymi cyklami miesięcznymi, oznaczono stężenie tryptofanu całkowitego, związanego i wolnego w surowicy. Stwierdzono, że u kobiet narażonych na przewlekłe działanie CS2 występuje znamienne podwyższenie stężeń wszystkich frakcji tryptofanu.

20

Effects of acidifier added to diets containing graded levels of crystalline tryptophan on growth performance, protein digestibility, and on brain serotonin level in broiler chickens

67%

Smulikowska S., Pastuszewska B., Tomaszewska-Zaremba D., Buraczewska L., Nguyen C. V., Mieczkowska A.

Journal of Animal and Feed Sciences

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2004

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tom 13

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nr 2

289-300

Ograniczanie wyników

The interaction of tryptophan and ANS with PAMAM dendrimers

The effect of immobilization in the PVA films on the fluorescence and phosphorescence lifetime of indole and its derivatives

Optimum ratio of standardized ileal digestible tryptophan to lysine for piglets

Spectroscopic studies of naproxen and tryptophan immobilized in polyvinyl alcohol

Plasma kynurenic acid concentration in patients undergoing cardiac surgery: effect of anaesthesia

Chemical composition and amino acid profile of Sardinella longiceps collected from Western coastal areas of Kerala, India

Secondary metabolites in the response of model Brassicaceae species to Plectosphaerella cucumerina

Fatigue development mechanisms during increased intensity exertion

Intramolecular electron transfer between tryptophan radical and tyrosine in oligoproline-bridged model peptides and hen egg-white lysozyme

Comparison of meat quality characteristics between commercial pigs and snails

Effect of cadmium on the peripheral kynurenine pathway in rats

Covalent modification and site-directed mutagenesis of an active site tryptophan of human prostatic acid phosphatase